Image processing apparatus.

Background of the Invention

Field of the Invention

The present invention relates to an image forming apparatus and, more particularly, to an image forming apparatus which can be used in a color copying machine which is capable of making color copies of an image of an original.

Related state of the art

Conventionally, an image forming apparatus reads an image of an original placed on an original platen or the like and performs a lifelike recording (copying) operation as instructed by an operator.

Advances in copying technology in recent years, together with color image recording technology, have made it possible to produce an image copy that is very close to the image of an original.

Accordingly, when banknotes or a certificate such as a security whose copying is prohibited is placed on the original edition and the machine is used for copying abusive or for "fun" or the like, copying is instructed with a conventional machine as instructed by the operator carried out. As a result, there is a possibility of forging documents, which is a major social problem.

US Patent No. 4,723,149 discloses an image forming apparatus for checking the copying of secret documents and includes a function for selecting an image forming area. A magnetic sensor sweeps a magnetic tape on the document and effects a switch to prevent a copy from being made or to obscure parts of the document by transmitting light to certain areas.

A method for preventing true-color reproduction of a colored pattern is known from US Pat. No. 4,325,981, in which a specially prepared photographic material is used which has a spectral reflection outside a certain wavelength range in such a way that part or all of the reproduction of the original takes place in a color that cannot be perceived by a direct human viewer.

These known methods of preventing copying have the disadvantage that they depend on the special physical properties of the original to be copied.

It is therefore an object of the present invention to provide an image forming apparatus with which it is possible to prevent counterfeiting of banknotes, securities or the like in advance, thereby solving the problem of the prior art described above.

According to the invention, an apparatus for image production is created, with a feed device for feeding electrical image data representing an original to be processed, a processing device for processing the electrical image data supplied by the feed device, and an output device controlled by the processing device, characterized by a determination device, the storage device contains in which an image or a spectral color range of the object of at least one specific original is stored in advance in the form of electrical data, for determining on the basis of the electrical image data of the feed device whether the image or the spectral color range, the or represented by this data, from which specific original is derived or not, and a control device for controlling a processing function within the device in dependence on the determination result of the determination device.

Furthermore, an image processing method according to the invention is provided with the steps of supplying electrical image signals representing an original, processing the electrical image data supplied in the supply step and outputting a processed image, characterized by determining, based on the electrical image data supplied in the supply step and an image or spectral color range of the object stored in the form of electrical data in a memory, of at least one specific original, whether the image or the spectral color range, the or represented by the supplied image data, derived or not derived from a specific original, and controlling a processing function of the method depending on the determination result of the determination step.

In addition, an image processing method according to the invention is created with the steps of supplying electrical image data representing an original, processing the electrical image data supplied in the supply step and outputting a reproduced image, characterized by determining, based on the electrical image data supplied in the supply step and an image or spectral color range of the object stored in the form of electrical data in a memory, of at least one specific original, whether the image or the spectral color range, the or which is represented by the supplied image data, is derived from a specific original or not, and controlling a processing function of the method depending on the determination result of the determination step.

If the original to be copied is a banknote or a security, the determination is made in this way and either the image production is controlled or the copy is destroyed.

Another object of the present invention is to provide an image forming apparatus which performs appropriate processing not only when an image is completely identical to a predetermined image, but also when an image similar to the particular image is input, which prevents counterfeiting.

For this purpose, in one example of the invention, a device for image production can be created, with an input device for inputting image information in the form of electrical data; determining means for determining, based on the electrical data and a specific original, to what extent an input image is similar to a predetermined image; conversion processing means for performing predetermined conversion processing of the input electric image data in accordance with the determination of the determination means. For example, if an image of a security, such as a bill of exchange or a stock, which may not be copied, is to be generated, the generated image changes according to the degree of similarity to such a security.

Another object of the invention is to provide an image forming apparatus with which it is possible to improve the accuracy of determining whether an input image is a predetermined image or not and to minimize the error rate due to incorrect determinations.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the drawings. Show it:

Figure 1 is a block diagram of a copier according to a first embodiment of the invention.

Fig. 2 is a schematic side sectional view of an example of the arrangement of an image reading device shown in Fig. 1;

3 is a schematic sectional side view of an example of the arrangement of an image output device;

4 is a flowchart showing an example of a control program according to the first embodiment;

Fig. 5 is a schematic view of an essential part of an apparatus for preventing copy output according to a second embodiment;

6 is a flowchart showing an example of a control method according to a third embodiment of the invention;

7 is a view of an image forming apparatus according to a fourth embodiment of the invention;

8 is a block diagram showing an example of the arrangement of a control unit included in a reading unit of this embodiment;

FIGS. 9A to 9C signal sequences of the timing control, which represent the functioning of the control unit;

Fig. 10 is a block diagram showing an example of an arrangement of a banknote stock detection circuit;

11 is a flowchart of an example of an image change processing method based on the result of the recognition;

12 is a block diagram of an arrangement of a banknote stock detection circuit according to a fifth embodiment;

Fig. 13 is a diagram illustrating the type of image change based on the arrangement shown in Fig. 12;

14 is a block diagram showing an example of an arrangement of a banknote stock detection circuit according to a sixth embodiment;

Fig. 15 is a diagram showing the kind of image change based on the arrangement shown in Fig. 14;

16 is a flowchart showing an example of an image change processing method based on the result of recognition according to a seventh embodiment;

17 is a block diagram of an example of an arrangement of a banknote stock detection circuit according to an eighth embodiment;

18 is a diagram showing the type of image change based on the result of recognition according to a seventh embodiment;

19 is a block diagram showing an example of an arrangement of a banknote stock detection circuit according to a ninth embodiment;

Fig. 20 is a diagram showing the kind of image change based on the arrangement shown in Fig. 19;

21 is a view of an image forming apparatus according to a tenth embodiment of the invention;

Fig. 22 is a block diagram showing an example of an arrangement of a video conversion circuit shown in Fig. 21;

Fig. 23 is a block diagram of another example of an arrangement of the video conversion circuit shown in Fig. 21;

24 is a view of an image forming apparatus according to an eleventh embodiment of the invention;

Fig. 25 is a block diagram showing an example of an arrangement of the video conversion circuit shown in Fig. 24;

26 is a block diagram of a circuit structure according to a twelfth embodiment;

Fig. 27 is a block diagram showing a construction of a detection circuit shown in Fig. 26; and

Fig. 28 is a plan view illustrating a state at the time of reading and scanning an input original.

Description of the preferred embodiments

Referring now to the drawing, there follows a detailed description of the preferred embodiments of the present invention.

1 shows a first exemplary embodiment of a device for image production according to the invention.

The device shown in FIG. 1 contains the following components: a central arithmetic processing device or CPU 1 in the form of a microcomputer; a read only memory (ROM) 2 in which a processing program and the like to be executed by the CPU 1 described later with reference to Fig. 4 are stored; a random access memory used in control processing by the CPU 1 for registration or the like, or RAM 3; a keyboard 4 with a known arrangement of input keys such as a key for commanding the start of copying and a key for setting the number of copies to be made; a keyboard interface 5 for connecting the keyboard 4 to a system multiple line or a system bus 10; an image reading device 6 for reading an image displayed on an original placed thereon; an image memory 7 for storing read image data; and an image output device 8 for outputting the stored image data; a banknote recognizer 9 for recognizing whether image data of a certificate such as money (hereinafter referred to as a banknote) or a security (hereinafter referred to as a share) whose copying is prohibited is present in the image memory; and an image data multi-line or an image data bus 11 for transmitting the image data between the respective components 6 to 9 at high speed.

Fig. 2 shows an example of an arrangement of the image reading device. As shown in this figure, the surface of the original is illuminated by a lamp 61 illuminating the original, a focal length adjustable lens 62 forms an image of the original on a reader and the image in electrical signals converting CCD element 63, and an original support surface 64 consists of a transparent plate. Reference numerals 65, 66 and 67 denote mirrors.

The lamp 61 illuminating the original and the mirror 65 shown in FIG. 2 scan an original 69 arranged with the surface to be read facing downward on the original support surface 64. The light reflected from the surface of the original is directed to the focal length adjustable lens 62 by the mirror assembly, and then an image is formed on the CCD element 63 converting this image into electrical signals.

3 shows an example of an arrangement of the image output device 8.

In Fig. 3, reference numerals 81Y, 81M, 81C and 81K each denote a primary charger for yellow, a primary charger for magenta, a primary charger for cyan and a primary charger for black. It should be noted that the letters Y, M, C and K added below accordingly indicate that the components designated with these letters are used for yellow, magenta, cyan and black, respectively.

A regular arrangement of luminescent diodes or an LED array 82 is switched on and off in response to image data, and a developing device 83 is used to apply a developer (toner or the like) of a corresponding color. Numeral 84 denotes a transfer charger, 85 a cleaner, and 86 a photoconductive drum.

A pick roller 87 picks up a recording medium 810 (hereinafter referred to as copy paper) contained in a paper feed cassette 811 by separating sheets of the copy paper piece by piece. Pairs of transport rollers 812-815 are arranged one behind the other for transporting the copy paper. A conveyor belt 816 is used for discharging the copy paper described, fixing rollers 88 are arranged in the vicinity of the discharge opening, and a tray 89 for discharged paper is used for stacking the copied paper on it.

FIG. 4 shows an example of a control method according to this embodiment, and the function of the arrangement described above will be described with reference to this figure.

First, a power switch (not shown) is turned on, the CPU 1 executes a predetermined initialization subroutine (step S1) and is set in the standby state to receive a command from the keyboard 4 after the temperature of the fixing roller 88 has a predetermined value has reached (step S3).

When an operator instructs copying using the keyboard 4, the CPU 1 drives the image reader 6 to read an image of the original (step S5). This image is read four times, changing one color filter at a time, and it is developed into the image memory 7 for each color (yellow, magenta, cyan, black).

The banknote recognition device 9 is then put into operation and a determination is made as to whether the image data in the image memory 7 is that of a banknote or a share (step S7). In this embodiment, if the address of a readable area of ​​the original platen 64 corresponds to that of a storage area of ​​the image memory 7, the determination can be made, for example, by recognizing the size of the original based on the size of a data development area of ​​the image memory 7 and this Result is compared with the size of banknotes and the like previously stored in the ROM 2 and the like. In addition, this determination can also be carried out by comparing the distribution of color spectra of the original with previously stored data.

If the size of the original is the size of a bill or the like, the bill recognizer 9 outputs "1", and if not, it outputs "0". If this output signal is "0", the CPU 1 outputs the image of the image memory 7 as a color image by means of the image output device 8 (step S11). On the other hand, when the output signal is "1", the CPU 1 prevents an image from being output (step S13).

In the image output processing (step S11), the image formation is carried out based on a known electrostatic method. In other words, after the photoconductive drum 86 is charged by the primary charger 81, the LED array 82 is turned on and off in accordance with the image data in synchronism with the rotation of the photoconductive drum 86, thereby forming a latent electrostatic image. This latent electrostatic image is developed by the developing device 83 by means of a developer (toner or the like) and transferred to the copy paper 810 fed by the pickup roller 87 by the transfer charger 84. The output of a color image is achieved by performing the processing described above for each of the colors yellow, magenta, cyan and black. Upon completion of the development of the specified colors, the copy paper 810 is transported to the fixing rollers 88 by the conveyor belt 816 for thermal fixing and then discharged to the paper tray 89.

On the other hand, the CPU 1 does not activate the image output device 8 in the processing in step S13, so that copying is prevented and no output is generated. In other words, when the original is a banknote or the like, an image is prevented from being output. In addition, there may be such an arrangement that a predetermined error message or a warning signal using a voice is output in connection with this processing.

In order to surely prevent the output of an image of a bank note or the like, in addition to preventing the operation of the image output device 8 described above, the prevention can be carried out beforehand. For example, if the feature of the original, such as the size of the original, becomes clear when the surface of the original is scanned four times, that is, for each color, the subsequent reading can be prevented at this time, thereby preventing the image from being output.

In addition, there may alternatively be an arrangement such that the output after the copying process is prevented by means of the image output device 8.

According to this embodiment, when a determination is made that the image is a particular image, the image is prevented from being output as described above in detail, so that it is possible to prevent counterfeiting of a banknote or the like.

Fig. 5 shows a second embodiment of the present invention for preventing the discharge after a copying operation. In this embodiment, the copy paper on which an image has already been formed is not discharged to the outside and is internally removed by cutting or the like.

Fig. 5 shows schematically an arrangement of the essential parts of this embodiment. In this embodiment, regardless of the type of the original, the process proceeds to the transfer of the image shown in Fig. 4 to the copy paper. If the output signal of the image recognition device 9 is "0", the conveyor belt 816 is converted to the one shown in FIG. 5 position indicated by a solid line, and the copy paper 810 is transported by the conveyor belt 816 to the fixing rollers 88, where the copy paper 810 is subjected to thermal fixing and is then discharged onto the paper tray 89. On the other hand, if the output signal of the image recognition device 9 is "1", that is to say that the original was a bank note or the like, the conveyor belt 816 is meanwhile moved into the position shown in FIG. 5 position indicated by a broken line. Then, the supplied copy paper 810 is passed through a guide 100 and transported to a cutter 101, where it is removed by cutting it into fine pieces, making it impossible to obtain a copy output.

Accordingly, according to this embodiment, before a fake reproduced image is output from the device, the copy paper is removed, thereby making it possible to prevent counterfeiting of a banknote or the like.

In the above embodiments, as a means for controlling the output of the copy, the operation of the image output device 8 is prevented or the copy is prevented from being discharged. Nevertheless, an arrangement can also be provided such that the operation of the image output device 8 itself is controlled in such a way that the copy of a banknote or the like is unusable.

6 illustrates an example of a control method according to a third embodiment of the present invention for rendering a copy of a banknote or the like unusable.

In this exemplary embodiment, the processing is carried out by means of steps S23 and S25 instead of step S13 according to FIG. 4.

In other words, when the banknote recognizer 9 recognizes a banknote, a stock or the like and outputs "1", the CPU 1 calculates a logical sum of the yellow, magenta and cyan images and a black image, and then converts the yellow, magenta and cyan Pictures into a black picture (step S23). Then, the CPU 1 outputs an image as a monochromatic image by the image output device 8 (step S25).

By outputting a monochromatic image, it becomes impossible for an operator attempting to make a counterfeit to accomplish this by simply using a copying machine.

In this embodiment, although it is assumed that the black copy is output as a monochromatic image, it is also possible to perform yellow, magenta, or cyan monochromatic copy. In particular, control of an image output device 8 of any kind is possible insofar as it is ensured that, from the point of view of making the forgery more difficult, at least no true-to-life full-color copy is produced. If a bill or the like is recognized before the completion of the above-described reading scan, if the copying is performed on the contents stored in the memory 7 up to this point, the full-color copying is not affected, so this method is equally effective.

In the above embodiments, although the determination of whether or not a copied original is a banknote or the like is made based on the document size, it is a matter of course that such determination can be made using any kind of means.

For example, there may be means used in automatic vending machines or the like to read a magnetic pattern of part or all of a banknote to compare the pattern with a previously stored pattern. In this case, it is possible to provide an arrangement in which a magnetic head is formed in the original cover arranged on the original supporting surface 64 for covering the end of the original 69. Alternatively, in a device with an automatic document feeder for originals (ADF), it is possible to use an arrangement in which a magnetic head is formed in the transport passage thereof.

In addition, it is also possible to use an arrangement in which part or all of the image pattern of a bank note or the like is read and the read pattern is compared with a previously stored pattern. For this reading process, in the case of a device with the construction of a digital copier as described above, the reading process of the image reading device 6 in the existing manner can be used. In the case of other types of devices, the reading head can be formed on the original cover or the transport passage of an ADF or the like. Alternatively, the lighting device can be formed on the original cover, and a comparison can be carried out by reading a watermark pattern.

Furthermore, it goes without saying that the present invention can be used regardless of the type of image output device 8. For example, although an arrangement using an LED array is used in the above-described embodiments for forming a latent electrostatic image on the photoconductive drum, an arrangement using a laser beam or the like may alternatively be used. In addition, the means for forming a latent electrostatic image on the photoconductive drum is not limited to such an electrophotographic type, but various other types can be used.

According to the third embodiment of the present invention, when an attempt is made to copy an object whose copying is prohibited, such as a banknote or a stock, the recognition is performed as described above and an output of the copying is controlled, which makes it possible to to carry out a desired lifelike copying. There is thus the advantage of being able to prevent counterfeiting in advance.

In this embodiment, when the color original is output by converting it to a monochrome image, it is possible to determine what the original looked like. In other words, if the stock is not copied for the purpose of forgery, but rather as a document, for example, a copy can be made.

7 schematically shows an example of an internal structure of a digital color copying system according to a fourth embodiment. As shown in the figure, this system includes a digital color image reading unit 401 (hereinafter referred to as a color reading device) arranged in the upper area and one in the lower area Area digital color image printing unit 402 (hereinafter referred to as a color printer). This color reading device 401 is used to read the color picture information of an original for each color by means of a color separation device and a photoelectric conversion element, for example a CCD element, described later, and to convert it into electrical, digital image signals. The color printer 402 is a laser beam color printer for recording by reproducing a color image for each color on the digital image signals and transferring them multiple times as digital pixels on a recording medium.

First, the representation of the color reader 401 will be described. An original is designated by reference numeral 403 and a glass plate 404 is used to place the original on it. A regular arrangement of rod lenses or a rod lens array 405 is used to concentrate an image reflected from the original scanned during the exposure and to image this image on a full-scale sensor 406 to scale, components 405, 406, 407 and 410 are used for scanning during the exposure in the direction of an arrow A1 displayed direction and together form an original scanning unit 411. Color separated image signals read for each line during scanning during exposure are amplified to a predetermined voltage by a sensor output signal amplifier circuit 407 and then supplied via a signal line 501 to a video processing device 412 to be described later to be subjected to signal processing , A detailed description of this arrangement will be given later. It should be noted that the signal line 501 is designed as a coaxial cable, in order to ensure a natural signal transmission.

A signal line 502 is used to supply a drive pulse for driving the full-color sensor 406 to scale, and all necessary drive pulses are generated by the video processing device 412. A white plate 408 and a black plate 409 are used to correct the white level and black level of video signals. When the white plate 408 and the black plate 409 are illuminated with a halogen exposure lamp 410, signal levels of the predetermined densities are obtained accordingly and can be used to correct the white level and the black level of the video signals.

A control device 413 containing a microcomputer carries out all of the following controls of the color reading device 401: displays on an operating console 420 by means of a collecting line or a bus 508; Controlling keyboard input, video processing means, and banknote stock feature extraction circuitry; Detecting the position of the original scanner 411 by means of position sensors S1, S2 via signal lines 509, 510; Controlling a stepper motor drive circuit 415 via a signal line 503 for gradually driving a stepper motor 414 to move the scanner 411; Switching the halogen exposure lamp 410 on / off by means of an exposure lamp drive circuit 421 via a signal line 504; Controlling the amount of light, and controlling a digitizer 416 via a signal line 505, an internal key and a display, etc.

A color image signal read by the above-mentioned exposure scanner 411 during scanning while exposing the original is supplied to the video processor 412 from the amplifier circuit 407 via the signal line 501. The color image signal is then subjected to various types of processing described later within the video signal processing device 412 and transmitted to the color printer 402 via an interface 456.

A description of the representation of the color printer 402 now follows. A scanning device is denoted by 711 and has a laser output section for converting a video signal of the color reading device 401 into an optical signal, a polygon mirror 712 of a polyhedron (eg octahedron) and a motor for Rotating this mirror 712, an f / o lens (imaging lens) 713, etc. A reflection mirror 714 is used to change the optical path of a laser beam, and a photoconductive drum is denoted by 715. A laser beam emerging from a laser output section is reflected by the polygon mirror 712 and transmitted through the lens 713 and the mirror 714 so that it linearly scans the surface of the photoconductive drum 715 (raster scan), thereby forming a latent image corresponding to the image of the original becomes.

In addition, reference numeral 717 denotes a primary charger; 718 a lamp that exposes the entire image; 723 cleaning means for recovering residual toner not transferred; and 724 a pre-transfer charger, all of which components are located near the photoconductive drum 715.

A developing device 726 serves to develop an electrostatic latent image formed on the surface of the photoconductive drum 715 by the exposure of the laser. Development cylinders 731Y, 731M, 731C, 731Bk contacting the photoconductive drum 715 directly effect development. Toner funnels 730Y, 730M, 730C, 730Bk are used to retain excess toner. Screws 732 are used to transfer the developer. These cylinders 731Y-731Bk, toner hopper 730Y-730Bk, and screws 732 constitute the developing device 726, and these components are arranged around a rotating shaft P of the developing device 726. For example, if a yellow toner image is formed, the development of the yellow toner is carried out in the position shown in the figure. At the time when a magenta toner image is formed, the developing device 726 is rotated around the shaft P as the center, and the developing cylinder 731M within a magenta developing device is placed in a position where it contacts the photoconductive drum 715. The development for cyan and black is carried out in a similar manner.

In addition, a transfer drum 716 serves to transfer a toner image formed on the photoconductive drum 715 to the copy paper. An actuator plate 719 serves to detect the movement position of the transfer drum 716. An origin position sensor 720 serves to detect the movement of the transmission drum 716 to an origin position when the transmission drum 716 is brought close to the actuator plate 719. Reference numeral 725 denotes a transfer drum cleaner; 728 an electrical discharge device; and 729 a transfer charger. These components 719, 720, 725, 729 are arranged around the transfer roller 716.

Paper feed cassettes 735, 736 are used to hold copy paper serving as a recording medium. Paper feed rollers 737, 738 are used to feed copy paper from the cassettes 735, 736. Synchronization rollers 739, 740, 741 are used to schedule the feeding and transportation of the paper. The paper fed and transported by means of these components is fed into a paper guide 749, wound around the transfer drum 716 with its end held by a gripper, and is then fed to the image formation.

Further, a drum drive motor 550 serves to synchronously rotate the photoconductive drum 715 and the transfer drum 716. A release gripper 750 serves to remove the paper from the transfer drum 716 after the image formation is completed. A conveyor belt 742 is used to convey the detached paper. An image fixing device 743 fixes the paper conveyed by the conveyor belt 742 and has a pair of heat pressure rollers 744, 745.

In addition, a printer control device serves to control the various parts of the printer 402 and has a PWM circuit 778 in order to subject the image information transmitted by the reading device 401 to pulse width modulation and then to supply it to the scanning device 711.

8, a detailed description of the controller 413 of the reader 401 according to the present invention follows.

(Control means)

The controller 413 includes a CPU 422 in the form of a microcomputer and controls both the video signal processing and the lamp drive circuit 421 for exposure and scanning, the stepping motor, in accordance with the contents stored in a program ROM 423, a RAM 424 and a RAM 425 Control circuit 415, digitizer 416 and control panel 420 via signal lines 508 (bus), 504, 503 and 505, etc. Incidentally, it is assumed for the RAM 425 that the non-volatility is ensured with the aid of a battery 431. A commonly used data line 505 is used for serial data transfer and the operator inputs necessary data based on a protocol between the CPU 422 and digitizer 416. Namely, the signal line 505 is a data line for inputting data for post-processing of the original, such as coordinates for the movement time, synthesis and the like, determination of area, determination of a copy mode or an enlargement, etc. Via the data line 503, the CPU 422 transmits commands to the motor drive circuit 415 which the scanning speed, distance, forward movement, backward movement, etc. Upon receiving a command from the CPU 422, the motor drive circuit 415 generates predetermined pulses that are supplied to the stepper motor 414, thereby driving the motor 414. Serial interfaces (I / Fs) 429, 430 are of a commonly used type consisting of LSI devices for serial interfaces, such as the 8251 device from Intel Corporation. The digitizer 416 and the motor drive circuit 415 are provided with similar circuits (not shown).

In addition, sensors S1, S2 are used to detect the position of the original exposure scanner (designated 411 in FIG. 7), S1 representing the original position in which the white level correction of the image signals takes place. The sensor S2 detects the fact that the original exposure scanner is located at the edge of the image, and this position serves as a reference position for the original.

(Printer Interface)

Signals ITOP, BD, VCLK, VIDEO, HSYNC, SCROM (511-516) are corresponding interface signals between the color printer 402 and the reader 401 shown in FIG. 7. All video signals VIDEO 514 read by the reader 401 are transmitted to the color printer 402 based on the signals mentioned above. ITOP 511 is a synchronization signal in the image feeding direction (hereinafter referred to as the sub-scanning direction). This synchronization signal is generated once each time the four colors (yellow, magenta, cyan, black) are transmitted, that is, four times in total on each such occasion. This signal is synchronized with the rotation of the transfer drum 716 and the photoconductive drum 715 so that it is aligned with the image on the edge of the original when the toner image starts to touch the copy paper wrapped around the transfer drum 716 of the color printer 402 with the photoconductive Drum 715 is transferred to the copy paper. This signal 511 is transmitted to the video processing device formed in the reading device 401 and is output by the control device 413 as an interrupt signal for the CPU 422.

The CPU 422 controls images in the sub-scanning direction for post-processing or the like by using the ITOP interrupt as a reference. BD 512 is a raster scan direction synchronization signal (hereinafter referred to as the main scan direction) which is generated once during each revolution of the polygon mirror 712, that is, once during each raster scan. The image signals read by the reader 401 are transmitted line by line to the printer 402 in the main scanning direction in synchronism with the signal BD 512. VCLK 513 is a synchronization clock signal for transmitting the 8-bit digital VIDEO signal 514 to the color printer 402 and enables the VIDEO signal 514 to be transmitted by means of bistable flip-flops 332, 335, as shown in FIG. 9B.

HSYNC 515 is a synchronization signal in the main scanning direction, which is generated in synchronism with VCLK 513 and has the same period as the signal BD 512. Specifically, the video signal 514 is transmitted in synchronism with HSYNC 515. This arrangement is used because the signal BD 512 generated in synchronism with the rotation of the polygon mirror 712 contains the flicker of the motor for rotating the polygon mirror 712 in large quantities, and if the VIDEO signal 514 were synchronized with the BD signal of this type, the flicker also would occur in the image, so that the signal HSYNC 515 is required, which is generated in synchronism with the flicker-free VCLK on the basis of the BD signal.

SRCOM is a data line for serial data transmission in half-duplex operation. As shown in FIG. 9C, a command CM is transmitted in synchronism with an 8-bit serial clock signal SCLK during the transmission of a synchronization signal CBUSY ("command busy") sent by the reading device. A status signal ST is then transmitted back in synchronism with a serial 8-bit clock signal occurring during the transmission of the SBUSY ("status busy") signal sent by the printer. All information transfers, including commands from the reading device to the printer, for example color mode and selection of a cassette, information about the printer status, for example paper jam, paper shortage, waiting, etc., take place via this transmission line SRCOM.

9A shows a timing diagram for transmitting a four-color (full-color) image based on the ITOP and HSYNC signals. ITOP 511 is generated once during one or two rotations of transfer drum 716. At a time 1, data of a "yellow image" is transferred from the reading device 401 to the printer 402. Accordingly, data of a "magenta image" are transmitted at a time 2, data 3 of a "cyan image" at a time 3 and data 4 of a "black image" at a time 4. A full color image with four colors superimposed on one another is thus produced on the copy paper. For example, if an image density of 16 picture elements / mm in relation to 420 mm in the longitudinal direction of an A3 size image is assumed in the feeding direction, HSYNC 420 * 16 = 6720 times is transmitted. At the same time, this signal is output to a clock input of a clock circuit 428 contained in the control device 413 and is used to supply an interrupt signal HINT 517 to the CPU 422 after a predetermined number of counting pulses has elapsed. Thus, the CPU 422 effects image control in the feeding direction, such as removal and movement.

(Bill-stock-feature extracting circuit)

10, a description will now be given of the function of a banknote stock feature extraction circuit 452.

Fig. 10 is a block diagram showing an example of the construction of the video processing device 412 including the banknote stock feature extraction circuit 452. The color image signal read by means of the exposure scanner 411 shown in FIG. 7 is fed to the video processing device 412 via the signal line 501 from the amplifier circuit 407. In this video processing device 412, this input signal is received by a video receiver circuit 460 and the false color coverage of each color and the mixed color are corrected by means of a video preprocessing device 461 in order to output RGB signals.

The preprocessed video signal is supplied to the banknote stock feature extraction circuit 452, and after being converted from a luminance signal to a density signal by a LOG conversion circuit 462, the signal is masked by a color withdrawal masking circuit 463 and subjected to color recovery (UCR = "under-color removal"). Then, the signal is processed by a slant image / mirror image processing circuit 464, a color matching circuit 465, a color conversion circuit 466, an enlargement circuit 467, a texture processing circuit 468, an edge emphasis smoothing circuit 469, a video signal - Synthesizing circuit 470 and a video driver circuit 471 and finally transmitted to the color printer 402 via the signal line VIDEO 8.

All processing circuits contained in the video processing device 412 are connected to one another by means of an internal bus VUBUS and also by means of a CPU bus transceiver 472 and to the CPU 422 via a signal line 508.

Based on the RGB signals supplied to the banknote stock feature extraction circuit 452, it is determined whether the input data matches the features of a predetermined bill or stock, and this determination result is supplied to the CPU 422 via the VUBUS.

Based on a determination result related to a number of features, the CPU 422 makes a final decision as to whether the examined original is a banknote or a stock or not. If the answer is YES, the CPU 422 sets a conversion parameter for a particular processing circuit via the VUBUS, the parameter being such that a lifelike picture of the original cannot be reproduced.

Processing for determining the match performed by the banknote stock feature extraction circuit 452 can be performed with respect to the RGB input signals by comparing with spectral color distribution data of the original previously stored in ROM or the like by a pattern of part or all of the image of the original is compared with previously stored pattern data, or by performing a combination of such processing. In addition to extracting features related to the content of the read image data, it is possible to provide other suitable processing such as adding circuitry or the like for determining the size, magnetic pattern, watermark pattern or the like of the original and supplying such data to the CPU 422.

11 shows an example of parameter change processing performed by the CPU 422 based on a determination based on the number of features obtained from the feature extraction circuit 452 described above. This processing can be stored in the ROM 423.

First, in step S101, various determination results from the aforementioned circuit 452 and others are input. Then, based on the entered results, a valid determination is made as to whether the examined original is a banknote or a share. According to this calculated result, a changing parameter in the processing circuit 463 or the like is set in step S105.

There now follows a description of examples for implementing the details of the parameter change.

The following formulas (a) to (d) are examples of a color change when it is determined that the original under examination is a banknote or a stock, and this processing is carried out by applying the color withdrawal mask circuit 463 related parameters of masking and UCR processing can be changed.

Formula (a) is an example of conventional masking, while when the matrix [mij] is changed to that shown in formula (b), the color is fundamentally different from that of the original, so that the recorded image is not a circulating banknote or share can be used. Nevertheless, the content of the share can be recorded.

Formula (c) also gives an example in which the image is printed in a specific color, while formula (d) is an example in which the image is printed in monochrome.

As described above, according to this embodiment, even in a case where it is determined that the original is a banknote or a stock, it is possible to make a copy, although not true to the original but sufficient, that described therein Determine content. It is therefore possible to keep the content of the share as a record.

Fig. 12 illustrates a fifth embodiment of the present invention. In this figure, reference numeral 450-2 denotes a banknote stock determination circuit, and in this example, a CPU is provided to perform control in accordance with the determination of a banknote or the like.

A signal 480 output to the masking / UCR processing circuit is used to control a color. The other functions are identical to those shown in FIG. 10.

In the event that conventional copying is to be performed as shown in Fig. 13 in (a), the masking / UCR processing circuit 463 is controlled so that the VIDEO 8 signal is synchronous with the ITOP signal output from the printer 402 in the Order of yellow, magenta, cyan and black is switched. When it is determined by the bill-stock determination circuit 450-2 that the original is a bill or a stock, the color of the printed image is changed by changing the order of the color sequence as shown in Fig. 13 in (b). will be changed.

Thus, since the masking / UCR processing circuit is directly controlled by the banknote stock determination circuit 450-2, it is possible to perform color changing processing independently of the CPU 422 so that the program of the CPU 422 is not complicated and even if the program of the CPU 422 is changed, the prevention of counterfeiting is ensured.

14 shows a sixth embodiment of the present invention.

A bus changeover signal 481 shown in this drawing is used to control a bus transceiver 472 associated with the CPU bus 508, and a banknote share determination circuit 450-3 operates independently of the CPU 422, constantly monitoring the RGB video signals. When it is determined that the original is a bill or a stock, the CPU bus transceiver 472 is locked to use the VUBUS only, and when, for example, a parameter is written into the slant / mirror processing circuit 464, it is possible to print an oblique image as shown in (a) in Fig. 15 or a mirror image as shown in (b) in Fig. 15.

When such conversion is forced, a printed image clearly distinguishable from an authentic printed image is output, thereby making it possible to prevent counterfeiting.

Figs. 15 (c) - (e) show other examples in which mirror images are output by controlling the slant / mirror processing circuit 464, where (c) is an example in which an output is output reduced by the magnification Circuit 467 is controlled, (d) is an example in which an output in the longitudinal transverse direction is independently enlarged by controlling the enlargement circuit 467, and (e) is an example in which an output with the addition of the characters "COPY" is output by controlling the video signal synthesizing circuit 470 and a character pattern generator 473.

In addition, the color matching can be changed significantly by controlling the color matching processing circuit 465. Alternatively, an image in a particular color (monochrome) can be output by controlling the color conversion circuit 466, or a black and white image can be output by controlling the color conversion circuit 466.

Further, an image in the form of a mosaic texture can be output by controlling the texture processing circuit, or fine lines can be deleted by filtering or blurring by controlling the edge highlight smoothing circuit 469. In addition, an image can be output by being subjected to a negative-positive conversion by means of the control of the LOG conversion circuit 462.

Since the arrangement is such that the anti-counterfeiting processing is performed in the video processing circuit 412, it is possible to prevent counterfeiting more securely.

Fig. 16 is a flowchart showing a seventh embodiment of the present invention.

In this embodiment, the CPU 422 calculates the degree of "similarity to a bill or stock" in the feature extraction circuit 452 and sets a conversion parameter for a particular processing circuit according to the level of "similarity to a bill or stock".

Since the processing of a match determination made by the feature extraction circuit 452 is identical to that shown in Fig. 7, the description thereof is omitted.

In particular, FIG. 16 shows an example of a parameter conversion processing program executed by the CPU 422 based on a number of evaluations obtained by the feature extraction circuit 452 described above. This program can be stored in the ROM 423.

First, in step S111, various evaluations (determination results) are input from the aforementioned circuit 452 and others. In step S113, a suitable calculation is then carried out on the basis of the evaluations, and a decision is made regarding the degree of "similarity to a banknote or share". In step S115, conversion parameters are determined according to the calculated result and set in the processing circuit 463 or the like. Incidentally, the above-mentioned degree and the conversion parameters can be stored in tables in the ROM 423 in advance.

An example of the content of parameters to be converted is now described.

The following formulas (e) and (f) are examples in which the color is changed according to the degree of similarity to a banknote or a stock. This processing is performed by changing masking / UCR parameters of masking / UCR processing circuit 463. Formula (e) is an example of conventional masking, and when the matrix [mij] is changed to the matrix shown in formula (f), the color is output by changing it according to the value α given by the Degree of similarity to a banknote or stock is determined. Accordingly, when α is large, the reproduced color is completely different from that of the original, so that the reproduced copy cannot be used as a circulable banknote or stock. Nevertheless, the content of the share (number or the like) can be retained as a record. With respect to an original whose degree of similarity to a banknote or a stock is small, the color change is suppressed to a small level by making α small. Incidentally, it goes without saying that methods other than the color changing method can be used

As described above, according to the seventh embodiment, since the image conversion is made according to the degree of similarity to a banknote or a stock, even for an original for which it is difficult to determine, it is possible to produce an image with a certain degree of image quality , Therefore, the number of copies for which a "defective copy" is determined can be reduced.

17 illustrates an eighth embodiment of the present invention.

In the figure, a banknote stock determination circuit is designated 450-2, and in this embodiment, the arrangement is such that the CPU is arranged to perform control according to the degree of "similarity to a banknote or stock". A signal line 488 is used to control the degree of a skew with respect to a skew / mirror image processing circuit 464.

When converted into an oblique image, the image structure is deformed as shown in FIG. 18. Due to the processing by means of the circuit 450-2, control can be carried out by means of a signal 488 in such a way that the degree of similarity with a banknote or share Θ is set from 90 ° to near 0 °.

Accordingly, in this embodiment, since the oblique / mirror image processing circuit 464 is directly controlled by the bill stock determination circuit 450-2 to a degree corresponding to the degree of similarity to a bill or stock, the counterfeiting prevention processing can be performed independently by the CPU 422. Thus, the program of the CPU 422 does not become complicated and it becomes more difficult for a potential counterfeiter to remove the counterfeit prevention processing.

19 illustrates a ninth embodiment of the present invention.

In the figure, a bus switch signal 481 is used to control a bus transceiver 472 with respect to the CPU bus 508 and a banknote stock determination circuit 450-5 continuously monitors the RGB video signals, being independent of the CPU 422 is working. If it is determined1 that the original is likely to be a banknote or stock, the CPU bus transceiver 472 is locked to use only the VUBUS. For example, when certain parameters are written into the bevel / mirror image processing circuit 464, it is possible to print an bevel image as shown in FIG.

Since such a conversion occurs to a degree corresponding to the degree of similarity to a banknote or stock when a determination is made that the original is obviously a banknote or stock (if the degree is large), it becomes clearly distinguishable from an authentic picture Printed image output, which makes it possible to prevent counterfeiting. On the other hand, if the determination is not clear (the degree is small), the conversion is carried out with a small degree, with the result that the possibility of unexpected difficulties for the operator is small.

Figs. 20 (a) - (c) show other examples in which the output processing is forcibly performed according to the degree.

Fig. 20 (a) is an example in which the image is outputted by reducing it according to the degree of similarity to a bill or a stock by the control of the enlargement circuit 467. In addition, Fig. 20 (b) also shows an example in which an image is outputted by being subjected to an independent longitudinal longitudinal enlargement according to the degree of similarity to a banknote or a stock. Furthermore, Fig. 20 (c) an example in which the characters "COPY" having a size or density corresponding to the degree of similarity to a bill or stock are added to an image by the video signal synthesizing circuit 470 and the character pattern generator 473 to be controlled.

In addition, the color matching can be changed by controlling the color matching circuit 465, or an image can be output according to the degree of its similarity in the manner of a mosaic texture by controlling the texture processing circuit. Alternatively, an image can be output by blurring processing according to the degree of its similarity by filtering by controlling the edge emphasis smoothing circuit 469.

Since the arrangement is such that the anti-counterfeiting processing is performed in the video processing circuit 412, it is possible to prevent counterfeiting more securely.

FIG. 21 illustrates an arrangement in which a counterfeit prevention device according to a tenth embodiment of the present invention is provided on the printer 402 side.

In this example, a banknote stock determination circuit 450-4 is provided in a printer controller 700 and monitors the video signals sequentially input thereto. Upon determining that the original is a bill or a stock in the same manner as described above, the bill stock determination circuit 450-4 controls the video conversion circuit 451. Then a printed image is substantially changed from an original by providing appropriate processing such as thinning the image, reducing or enlarging lines, using gray points, and adding characters.

22 illustrates an example of the video conversion circuit 451 used to effect the thinning out. In the figure, reference numeral 901 denotes a selector, while reference numeral 902 denotes an AND gate. Numeral 903 denotes a JK flip-flop that performs thinning for each selected picture element.

Fig. 23 is an example of a video converting circuit 451 'for reducing (or enlarging) lines. In this figure, reference numerals 910, 911 and 913 denote D flip-flops, while reference numeral 912 denotes a selector. Reference numeral 914 denotes a comparator, and if such an arrangement is provided that a small (or large) value is selected by means of the selector 912, it is possible to make lines in the main scanning direction smaller (or larger).

An example of a processing circuit related to gray scale processing is not shown, however, such an arrangement may be provided that a fine pattern of a bill or the like forms a moiré pattern by subjecting a video image to fine point processing.

In this embodiment, since a counterfeit prevention device is included on the printer side as described above, even in a case where an image is read by a reading device not provided with a counterfeit prevention device, one is possible To effectively prevent counterfeiting.

Note that the circuit for determining a bill or a stock is not limited to that of the above-described embodiments, and it goes without saying that any circuit can be used for the same purpose. In addition, it also applies to the printer that not only the electrophotographic types of the above-described embodiments can be used, but also various other types.

24 illustrates an example according to an eleventh embodiment of the present invention, in which a counterfeit prevention device is provided on the printer 402 side.

In the figure, a banknote share determination circuit provided in the printer control device 700 is designated 450-6 and monitors the video signals which have been sequentially input to it. Upon determining that the original is a bill or a stock in the same manner as described above, the bill stock determination circuit 450-6 controls the video conversion circuit 451 according to the aforementioned degree of "similarity". Then, a printed image is substantially changed from an original by providing appropriate processing according to the degree, such as thinning the image, reducing or enlarging lines, using grayscale dots, and adding characters.

25 illustrates an example of the video conversion circuit 451 used for thinning out. In the figure, reference numeral 1001 denotes a selector, while 1002 denotes an AND gate. An n division counter 1003 outputs "1" for each number of picture elements divisible by n, and the selector 1001 selects 0 by means of the AND gate 1002 instead of the signals once for each number of picture elements divisible by n, thereby reducing the thinning Function is performed.

In this embodiment, since a counterfeit prevention device is included on the printer side as described above, even in a case where an image is read by a reading device not provided with a counterfeit prevention device, one is possible To effectively prevent counterfeiting.

Note that the circuit for determining a bill or a stock is not limited to that of the above-described embodiments, and it goes without saying that each circuit can be used for the same purpose. In addition, it also applies to the printer that not only the electrophotographic types of the above-described embodiments can be used, but also various other types.

Fig. 26 is a block diagram of a twelfth embodiment of the present invention applied to a color image reproduction apparatus using a laser beam printer.

In the figure, a color original 2101 to be reproduced is arranged on a glass original support surface 2102. A light source 2103 serves to illuminate the original 2101, while a bundling rod lens array 2104 (for example Selfock (trade name) lens array) on a CCD line sensor 2105 provides an image of the light reflected by the original illuminated by the light source 2103 (a Image of the original). The CCD line sensor 2105 is arranged such that filters for red (R), green (G) and blue (B) are alternately applied to the line, and converts the image of the original into electrical signals by dividing it into the three Basic colors disassembled. The above-mentioned components 2103-2105 are housed together as a unit in a read head (carriage) and effect a scanning in the direction indicated by the arrow shown in the figure (sub-scanning direction) by means of a scanning device (not shown), whereby the on the Original 2101 displayed image is scanned and read.

In addition, a sample and hold circuit 2106 samples and holds analog electrical signals (video signals) sent by the line sensor 2105 and converts them into time-serial R, G, B signals. An A / D (analog-digital) converter 2107 subjects the signals output by this sample-and-hold circuit 2106 to an analog-digital conversion. A shading correction circuit 2108 corrects changes in sensitivity for a CCD line of the CCD line sensor 2105 and inequality in lighting. A log conversion circuit 2109 converts the R, G and B signals corrected by the shading correction circuit 2108 into complementary color density signals for cyan (C), magenta (H) and yellow (G). Reference numeral 2110 denotes a color application circuit for generating ink signals (K, black) by extracting the minimum value among the C, M and Y signals output from the log conversion circuit 2109, and also denotes a UCR circuit for subtracting one from the K Signal corresponding component of the C, M and Y signals. A masking circuit 2111 corrects unnecessary absorption and the like of an output colorant. A selection circuit 2112 selects the signals to be supplied to the printer (in this embodiment, a laser printer) from the Y, M, C and K signals obtained as described above.

In addition, a gate circuit 2113 switches output signals on and off which are transmitted from the selection circuit 2112 to the printer in response to a control signal from a CPU (central arithmetic processing unit) 2128. A D / A (digital / analog) converter 2144 converts digital signals sent from the reading device via the gate circuit 2113 into analog signals. A comparator 2116 compares the output signals of the D / A converter 2114 with a triangular wave signal of a predetermined period generated by a triangular wave generator 2115, whereby a pulse width modulated (PWM) signal with a pulse width proportional to the image signal is obtained. This PWM signal is fed to a semiconductor laser 2118 by means of a laser drive circuit 2117.

The light beam emanating from the semiconductor laser 2118 is modulated by this PWM signal and reaches a rotating photoconductive drum 2121 by means of a polygon mirror 2119 rotating at high speed and a reflection mirror 2120 (cf. the broken line in the figure).

A latent electrostatic image formed on the photoconductive drum 2121 upon application of the laser beam is sequentially developed in a C, M, Y and K order by a rotating developing device 2122 and recorded as toner images of the corresponding colors. This toner image is transferred sequentially in the order of C, M, Y and K onto copy paper 2124 on the transfer roller 2123. The copy paper 2124 is fed from a paper cassette (not shown) and wound around the transfer roller 2123. After the completion of the transfer of the C, M, Y and K images after four processes, the copy paper 2124 is subjected to thermal fixing by means of a fixing device 2126 and discharged to the outside as a final reproduced image.

A determination circuit 2127 determines whether the pattern on the original 2101 is a specific pattern and is controlled by the CPU 2128.

With the arrangement described above, with reference to the original 2101, it is necessary to scan and read four times in synchronism with the C, M, Y and K output signals of the printer, and the selection circuit 2112 switches the output signals and transmits C, M, Y or K corresponding signals to the printer. In this embodiment, therefore, the arrangement is such that the determination circuit 2127 uses a different algorithm according to the number of times the original is scanned, and its determination results are evaluated in a comprehensive manner, thereby improving the accuracy with which a particular pattern is determined becomes.

Referring now to FIG. 27, there follows a detailed description of the operation of the determination circuit 2127 described above. FIG. 27 shows a detailed internal circuit structure of the determination circuit 2127. The R, G and B signals from the shading shown in FIG. 26 Correction circuit 2108 are each subjected to binary processing with reference to predetermined threshold values ​​by means of comparators 2201-2203. An AND circuit 2205 computes a logical product of the results of this binary processing and outputs only at pixel "1" that exceeds the threshold with respect to all components, R, G and B.

A corner point detection circuit 2206 detects a corner point of the image of the original, and when, as shown in Fig. 28, a bill 2302, that is, the original 2101, is placed on the original glass platen 2102, this circuit 2206 detects a corner point one side of banknote 2302 (a point on a straight line 2303). An angle detection circuit 2207 detects an angle of rotation Θ (see FIG. 28) the banknote 2302 based on the detection result obtained by the detection circuit 2206. An affine converting circuit 2208 cuts off a part (for example, a hatched part shown in Fig. 28 with 2304 in Fig. 28) of an input image of the original based on the detection result Θ of the angle detecting circuit 2207 and rotates it by (-Θ) around it store in a memory 2209.

Due to the arrangement described above, an image is saved in a memory 2209 in a state in which the cut portion 2304 is not rotated. Meanwhile, a normal image pattern corresponding to the cut image pattern 2304 mentioned above is stored in a memory 2210 by the CPU 2128. Then, the content of the memory 2209 and the content of the memory 2210 are superimposed on each other in a matching circuit 2211 and a value of their correlation is determined. The correlation value determined by the matching circuit 2211 is again output to the CPU 2128, from which, based on the value of the correlation, a determination is made as to whether the input image matches a normal image pattern (hereinafter referred to as a normal pattern).

With the procedure described above, there is obviously an uncertainty of ± 180 ° in the angle detection with the angle detection circuit 2207, so that a single calculation of the match does not lead to a correct determination with respect to an image inverted by 180 °. For this reason, in this embodiment, if an erected correct pattern is stored in the memory 2210 the first time the original is scanned, while an inverted (180 ° inverted) correct pattern is stored therein the second time the original is scanned, the 180 ° uncertainty can be saved with two scans - and determination processes are overcome. In Fig. 26 namely, the first scan and determination are made to obtain an output signal corresponding to a cyan image, while the second scan and determination are carried out to obtain an output signal corresponding to a magenta image, and if a determination is based on one of the two determination results if the entered image matches the correct pattern, the CPU 2128 immediately switches off the gate circuit 2113, thereby preventing the image signal from being output to the printer. Because of this arrangement, since at least the yellow image and the black image are not written on the photoconductive drum 2121, the reproduced image output on the copy paper can be clearly distinguished from the input original, making it impossible to use them for the purpose of To use fake.

A modification of this embodiment will be described with reference to FIG. 27. With this modification, the above-described 180 degree uncertainty can be overcome at once by providing two copies of the circuit having a structure as shown in FIG. Furthermore, the reading density for the first scan and the second scan is changed. Namely, during the first read scan, an image thinned for each picture element is stored in the affine converting circuit 2208 in the memory 2209, while the image during the second read scan is not thinned and in the memory 2209 as it is, with the density read, is saved. Correct patterns corresponding to corresponding densities are stored in memory 2210 in advance. With this arrangement, even in cases where it is impossible to obtain a value of sufficient correlation during the first match processing, the CPU 2128 can determine that the input image matches the correct pattern if a value of high correlation during the second match processing can be obtained.

It is conceivable that the following different types are assumed as other exemplary embodiments:

The threshold values ​​supplied to the comparators 2201 and 2203 shown in FIG. 27 are changed during the first and second sampling.

An image to be written into the memory 2209 shown in FIG. 27 is shifted by the portion of a number of picture elements during the first and second scanning, thereby absorbing the misrecord between the input pattern and the correct pattern.

The image to be written into the memory 2210 shown in FIG. 27 is changed during the first and second scanning. For example, the pattern of a ten thousand yen banknote is used during the first scan, while the pattern is changed to the pattern of a thousand yen banknote during the second scan.

It is a matter of course that in the above embodiment, the number of scans is not limited to two. In addition, the number of scans is not limited to four or less. For example, the following processing is possible: If, during four or fewer scans, a determination is made that the input image is close to a correct pattern, the determination processing is continued by merely scanning the original without discharging the copy paper from the transfer roller 2123, and the fifth transfer is performed if the input image matches the correct pattern, and then the entire surface of the duplicated copy is erased.

The following is a description of another modification of the twelfth embodiment of the present invention.

With this modification, an image is not output during the determination processing of the first scan, and if it is determined in this processing that the original is close to the correct pattern of a bill or the like, the scanning is stopped at that time. If it is not determined that the original is close to the correct pattern, four image reads corresponding to C, M, Y and K images are continuously performed and video signals are supplied to the printer, thereby outputting a duplicated image.

When the scanning is temporarily stopped, a message is issued from the CPU 2128 to a liquid crystal display device 2130 or the like to cause the operator to rearrange the original or take other appropriate measures, thereby encouraging restarting. When a resume is determined by a key 2131, the determination and duplication processing are restarted as described above.

Because of this arrangement, it is possible to overcome errors in the determination caused by a slight mispositioning of the original, angular errors thereof, etc.

The method described above for determining a specific image by abstracting a specific pattern can be applied to all of the exemplary embodiments described above.

As described above, according to the twelfth embodiment of the present invention, the function of making a determination by extracting a certain pattern from an image of the original is repeated several times, and the results of the repeated determinations are evaluated in a comprehensive manner, thereby making a final determination of whether a certain pattern is included in an image of the original or not. Thus, it is possible to achieve the following advantages: the accuracy with which the determination is made is significantly improved, and the counterfeit prevention function in the color image copying machine is improved. At the same time, the possibility of hindering normal copying is reduced by a remarkable degree.

The present invention is not limited to the exemplary embodiments described above and various other modifications are possible without leaving the scope of the patent claims.