Print control device and its control method

The present invention relates to a print control device and a control method thereof.

A print control device that is connected to a host via a network and is connected to a plurality of printers to transfer print data transmitted from the host to the printer specified by the host is known in Patent Document 1. Has been printed.

In addition, a print system that uses the output function of a resource sharing system such as LAN has been known for a long time. For example, in Patent Document 1, an output command is wrapped in a TCP header or an IP header from a terminal to a print server via LAN. The technique of transmission is known in Patent Document 2 and the like.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 63-163627</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 3-065721</text></patcit>

<p> Recently, networking is progressing, and large-scale networking with LANs all over intelligent buildings is progressing. Furthermore, nationwide networks such as WAN (Wide Area Network) that are directly connected to LAN by public lines, and advanced information networks such as ISDN are being developed. Under such circumstances, via host computers and networks. A more efficient process related to image processing is desired in a print control device capable of communicating with the user. However, as disclosed in Patent Documents 1 and 2, in the conventional print data or print control command, the print control device that receives the data performs a great deal of analysis processing to identify what the received data is. It is necessary, for example, a large amount of analysis processing is required to identify whether the received data is print data or a print control command, and there is a mechanism that enables faster processing of the print control device. desired.</p>

<p> In order to achieve such an object, in the present invention, in a print control device capable of communicating with a host computer via a network, a packet to which the attribute of the packet generated by the host computer is attached includes data of the attribute of print data. When the first packet is received and the second packet containing the attribute that can be identified as the print data to be output is received, the processing of the print data extracted from the received second packet is converted into the data of the first packet. The purpose is to provide a mechanism to carry out based on.</p><p> Alternatively, the packet tagged with the packet generated by the host computer receives the first packet consisting of the data of the attributes of the print data, and further, the processing of the received print data is performed on the print data based on the tag. The purpose is to provide a mechanism based on the data contained in the packet recognized as the first packet consisting of the attribute data.</p>

<p> According to the present invention, the print data itself or the attributes of the print data and various control instructions themselves are generated in a form that can be distinguished as a packet with a tag (attribute), and the tag of the packet is recognized by the print control device. In addition to being able to distinguish between the two, the data in the packet can be interpreted, and processing related to printing and image processing can be performed, so that the processing of the print control device can be speeded up.</p><p> For example, in a network environment, even when data of various formats or uses are transmitted from multiple host computers, when analyzing character combinations in order to identify what the transmitted data is. Compared with this, it is possible to realize a print control device capable of performing faster processing.</p>

Hereinafter, the present invention will be described with reference to preferred examples.

In FIG. 1, 101 is a host computer, 102 is a scanner printer server, 103a to 103b are various scanners, 104a to 104d are various printers, and 105 is Ethernet (R).

106 is the client process, 107 is the server process, 108 is DATA (image data signal), 109 is VSYNC (vertical sync signal), 110 is HSYNC (horizontal sync signal), 111 is CLOCK (clock signal), 112 is S.COM (scanner serial command signal) and 113 represent P.COM (printer serial command signal).

Further, DATA (image data signal) 108, VSYNC (vertical synchronization signal) 109, HSYNC (horizontal synchronization signal) 110, and CLOCK (clock signal) 111 are collectively referred to as Video I / F.

Different scanner printers with different interfaces, such as SCSI for connections with 103b and 104b scanner printers, Centronics I / F for 104c printer connections, and RS232C for 104d connections. The configuration of the connection is shown. Generally, devices connected to SCSI are in the form of both a scanner and a printer, and the Centronics I / F and RS232C are often connected to a printer . Scanners and printers connected to such I / Fs have different built-in functions.

In the case of Video I / F, since it is an interface that mainly exchanges raw image data, many connected scanners and printers do not have a page description language expansion function or compression / decompression function.

Hereinafter, the scanner is generically referred to as 103, the printer is collectively referred to as 104, and the interface will be described by taking Video I / F as an example.

The host computer 101 is made to execute a client process 106 for controlling various scanners 103a to 103b or printers 104a to 104d.

In the scanner printer server 102, the server process 107 that controls the scanner 103 (hereinafter referred to as 103a to 103b) and the printer 104 (hereinafter referred to as 104a to 104d) is executed based on the control of the client process 106. Keep it.

The client process 106 communicates with the server process 107 via Ethernet (R) 105 to read the image from the scanner 103 and print the image to the printer 104. It is also possible to copy independently between the scanner 103 and the printer 104.

FIG. 2 is a configuration diagram of the scanner printer server 102.

201 is CPU, 202 is Ethernet (R) controller, 203 is RAM, 204 is ROM, 205, 206 is dual port ram, 207 is serial interface, 208 is timing control circuit, 209 is main bus, 210 is data bus, 211 is A disk interface, 212 is a hard disk, 213 is an encoding / decoding circuit, and 214 is an interprinter for developing a page description language.

When the scanner printer server 102 is started, the CPU 201 starts the program of the ROM 204 and executes the server process 107 with the RAM 203 as a temporary storage location. At this time, the Ethernet (R) controller 202 can connect to the Ethernet (R) 105 and communicate with the client process 106 of the host computer 101.

The serial interface 207 serially communicates commands between the scanner printer server 102, the scanner 103, and the printer 104.

The dual port rams 205 and 206 can be accessed from both the main bus 209 and the data bus 210. These dual port rams 205 and 206 are controlled by the timing control circuit 208, and transfer data between the scanner 103 and the printer 104 in a dual buffer system. The transfer at this time is performed synchronously, and is synchronized with VSYNC (vertical synchronization signal) 109, HSYNC (horizontal synchronization signal) 110, and CLOCK (clock signal) 111 signals.

The serial interface 207 communicates a command with the scanner 103 by serial transmission using S.COM (scanner serial command signal) 112. Similarly, the command with the printer 104 is communicated by serial transmission with P.COM (printer serial command signal) 113.

As this data, a pre-scan command, a scan command, and the like are sent from the scanner printer server 102 to the scanner 103. Further, the scanner 103 side sends a copy command, status information such as an operation abnormality, and the like. Similarly, a print command or the like is sent from the scanner printer server 102 to the printer 104. In addition, status information such as out of paper and abnormal paper jam operation is sent from the printer 104 side.

The disk interface 211 interfaces with the hard disk 212.

The coding / decoding circuit 213 encodes the data read from the scanner 103. It also decodes the encoded image data sent from Ethernet (R) 105. As this coding method, there is an ADCT method and the like.

The ADCT coding method is a color still image coding method that is being standardized by JPEG (joint Photograpics Expert Group), which is a joint organization of CCITTS GVIII and ISO / TC97 / SC2 / WG8, aiming for the official recommendation of 1991 (Nikkei). Electronics See March 19, 1990).

The interpreter 214 is a means for translating a PDL (Page Description Language), expanding an image on a dual port ram 205 or 206 as a bitmap or a byte map, and printing it on a printer 104. This PDL includes PostScript and CaPSL (CA nonprinting System Language).

FIG. 3 is a configuration diagram of the scanner 103.

301 is a scanner serial interface, 302 is a scanner CPU, 303 is a scanner drive circuit, 304 is a scanner timing control circuit, 305 is an image reader, and 306 is an operation panel.

The operation when scanning an image will be described with reference to FIG.

The scanner serial interface 301 receives a scan command from the scanner printer server 102 and transmits it to the scanner CPU 302.

Next, the scanner CPU 302 sets the image size, the scan start position of the image, and the like from the scan command.

The scanner CPU 302 controls the scanner drive circuit 303, and reads an image from the image reading unit 305 line by line as shown in FIG. 7.

At this time, as shown in FIG. 8, the scanner timing control circuit 304 uses HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111, and DATA (image data) the image data synchronized with these. Signal) Output to 108.

The scanner / printer server 102 reads image data in synchronization with HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111.

FIG. 4 is a configuration diagram of the printer 104.

401 is a printer serial interface, 402 is a printer CPU, 403 is a printer drive circuit, 404 is a printer timing control circuit, and 405 is a print unit.

The operation when printing an image will be described with reference to FIG.

The host computer 101 prepares the data to be printed. The data is in the form of raw image data, compressed image data, page description language, and the like. Then, specify the printer you want to print, and transfer it to the scanner printer server 102 via the network 105. The client process 107 on the server 102 transfers the data in the server 102 if the transferred data is in the form of a page description language and the specified printer does not have the ability to expand the bitmap in the page description language. Expand and send a print command to printer 104 from the interface to which the specified printer is connected. If the connected printer has a page description language expansion function, the server 102 sends data to the printer 104 in the form of page description language data.

The server 102 automatically performs processing in the server based on the relationship between the sent data and the built-in function of the specified printer.

When using the printer built-in function, the server 102 has only the data transfer function. Hereinafter, the case where the printer connected to the server 102 does not have the built-in function will be described.

The printer serial interface 401 receives a print instruction from the scanner printer server 102 and transmits the print instruction to the printer CPU 402.

Next, the printer CPU 402 sets the information sent together with the print data, or in the case of the page description language format, the image size, the print start position of the image, and the like according to the specification.

The printer CPU 402 controls the printer drive circuit 403 and reads out an image line by line as shown in FIG.

At this time, as shown in FIG. 8, the scanner / printer server 102 outputs HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and image data to the printer 104 in synchronization with the HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111. To do.

The printer timing control circuit 404 receives image data in synchronization with HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111 from the scanner printer server 102, and prints the image data on the print unit 405. ..

FIG. 5 is a configuration diagram of an image reading unit 305 that does not have a compression function and outputs raw image data.

FIG. 5 is a configuration diagram of the image reading unit 305.

501 is a level conversion unit, 502 is a scanner gamma conversion unit, 503 is a scanner color conversion unit, 504 is a resolution conversion unit, and 505 is a scan engine.

In FIG. 5, the image reading unit 305 is composed of a level conversion unit 501, a scanner gamma conversion unit 502, a scanner color conversion unit 503, a resolution conversion unit 504, a scanning conversion unit 505, and a scan engine 505. It is connected to (shown) and can convert parameters from the scanner CPU 302.

The scan engine 505 reads an RGB color image, performs shading correction, and outputs image data.

The resolution conversion unit 504 converts the reading resolution of the image. This resolution can be selected from 400dpi (dotperinch), 200dpi, 100dpi and so on. This resolution is specified by the scanner CPU 302.

The scanner color conversion unit 503 performs color conversion of the image. Here, if the desired image data is RGB data of standard color space data, the image data is corrected and output according to the RGB data. In addition, RGB color data is also converted to data in a color space such as YCrCb here. When black-and-white data is desired to be obtained, black-and-white conversion is performed by using Y, which is the brightness data of YCrCb, or by using G (Green) data, which is intermediate wavelength data of RGB color data. The scanner CPU 302 specifies this scanner color conversion.

The level conversion unit 501 converts the number of effective bits of one pixel. For example, the dynamic range of YCrCb of 8 bits for each color after gamma conversion is converted by truncating the lower bits so that Y is 6 bits and Cr and Cb are 4 bits each. This level is specified by the scanner CPU 302 according to the instruction of the host computer 101.

FIG. 6 is a configuration diagram of the print unit 405.

601 is a printer color conversion unit, 602 is a printer gamma conversion unit, 603 is a masking conversion unit, 604 is a black generation and undercolor removal unit, 605 is a binarization unit, and 606 is a print engine.

The printer color conversion unit 601 performs color conversion of the image to RGB. Here, for example, when an image is sent in a color space such as YCrCB, it is converted to RGB.

The printer gamma conversion unit 602 performs gamma conversion of the input image. R'= f (R) G'= f (G) B'= f (B) This conversion is done by a LUT (look-up table). The printer CPU 402 sets this LUT.

The masking conversion unit 603 performs masking conversion of the input image.

Here, the masking conversion is

<maths num="1"><img file="JP2004046899A_D0001.tif" /></maths>

Primary transformation of, or

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It is obtained by the quadratic transformation of.

This conversion is done by a LUT (look-up table) or a gate array. The printer CPU 402 sets the parameters of this LUT or gate array.

In the black generation and undercolor removal section 604, C = 255-R M = 255-G Y = 255-B Bk = a (min (C, M, Y)) C'= C-BkM'= M As shown by -BkY'= Y-Bk, black generation and undercolor removal are performed.

This conversion is performed by a LUT (look-up tape) or a gate array. The printer CPU 402 sets the parameters of this LUT or gate array.

In the binarization unit 605, when the print engine 606 is a binary printer, the image is binarized. As the binarization method, three types of the simple binarization method, the dither method, and the error diffusion method are used by switching. If the print engine 606 is a multi-value printer, the binarization unit 605 is not required. This conversion is done in a gate array. The printer CPU 402 sets the binarization method, the binarization threshold, and so on.

FIG. 7 is an explanatory diagram of scanning or printing an image, and 701 refers to an image to be scanned or printed.

VSYNC represents a vertical sync signal, HSYNC represents a horizontal sync signal, and the image 701 to be scanned or printed is output line by line in synchronization with the vertical sync signal and the horizontal sync signal.

FIG. 8 is an explanatory diagram of timing. VSYNC represents a vertical synchronization signal, HSYNC represents a horizontal synchronization, CLOCK represents a reference clock, and image data is output for each pixel in synchronization with CLOCK.

In FIG. 8, although it is RGB color data, the scanner color conversion unit 503 can convert it into any three primary colors.

FIG. 9 is an explanatory diagram of the operation of the dual port ram during prescan and print. As shown in the figure, one line of the image is read from the dual port ram to the scanner 103 or written from the dual port ram to the printer 104 as shown in the figure. To.

The numbers in FIG. 9 represent the access order of the dual port ram at this time.

10 and 11 are explanations of dual port ram operation during prescan.

When reading an image from the scanner 103, the scanner printer server 102 alternately writes the image data to the dual port ram for each line as shown in FIGS. 10 and 11. That is, as shown in FIG. 10, the first line is read from the scanner 103 and written to the dual port ram 205.

Next, as shown in FIG. 11, the second line is read from the scanner 103 and written to the dual port ram 206. If the host computer 101 wants to obtain the raw image data, it reads the data of the dual port ram 205 as it is and transfers it to the server wrestling 107 via Ethernet (R) 105. If you want to obtain it in the form of compressed image data, use the coding circuit 213 in the server device shown in Fig. 2 to read the data of the dual port ram 205, compress the image, and use Ethernet (R) 105. Transfer to server process 107 via.

Next, as shown in FIG. 10, the third line is read from the scanner 103 and written to the dual port ram 205. At the same time, the data of the second line of the dual port ram 206 is read and similarly transferred to the server process 107 via Ethernet (R) 105 in the form of raw image data or compressed image data.

Similarly, the dual buffer is used to read the images line by line.

By the way, the scan engine 505 reads out images in sequence of RGB points. If the user instructs to read the image in another format such as line sequential or surface sequential, it is necessary to perform scanning conversion. This is done when reading images from the dual port rams 205, 206.

The scanning conversion at the time of scanning will be described below.

First, it is assumed that the scanner color conversion unit 503 converts the point-sequential RGB into a color space such as YCrCb, and alternately writes the point-sequential dual port rams 205 and 206. To convert this point-sequential YCrCb image into line-sequential and transfer it, when reading the image data, shift it by 3 pixels and read it. That is, only Y, which is the first color, is first read from the point-sequential YCrCb image and transferred. Next, only the second color, Cr, is read and transferred. Finally, only the third color, Cb, is read and transferred. As a result, scanning conversion from point-sequential YCrCb to line-sequential YCrCb images is performed.

Next, a case where a point-sequential YCrCb image is converted into a surface-sequential YCrCb and transferred will be described.

As in the case of line sequential, the scanner color conversion unit 503 converts RGB of point sequential into a color space such as YCrCb, and it is assumed that RGB of point sequential is alternately written to dual port rams 205 and 206 in point sequential.

Since the conversion from point-sequential to surface-sequential cannot be performed by one scan, the scan engine 505 scans three times.

Then, at the time of the first scan, only Y of the first color is read and transferred. At the time of the second scan, only Cr is read and transferred, and at the time of the third scan, only Cb is read and transferred. This makes it possible to convert a point-sequential YCrCb image to a surface-sequential YCrCb.

Further, in the case of a point-sequential YCrCb image, the image can be coded by the ADCT method. In this case as well, the images read from the scanner 103 are alternately written to the dual port ram, coded by the coding / decoding circuit 213 at the time of reading, and the encoded image data is written to the RAM 203. The encoded image data is transferred to the server process 107 via Ethernet (R) 105.

As a result, the image can be compressed and transferred, and the amount of communication can be reduced.

12 and 13 are explanatory views of dual port ram operation during printing.

When printing an image on the printer 104, the scanner printer server 102 alternately outputs data to the printer 104 from the dual port ram as shown in FIGS. 12 and 13 for each line.

That is, as shown in FIG. 12, the first line is read from the Ethernet (R) 105 and written to the dual port ram 205.

Next, the second line is read from Ethernet (R) 105 as shown in FIG. 13 and written to dual port ram 206. At the same time, the data of the dual port ram 205 is read out and transferred to the printer 104.

Next, as shown in FIG. 12, the third line is read from the Ethernet (R) 105 and written to the dual port ram 205. At the same time, the data is read to the dual port ram 206 and transferred to the printer 104.

Similarly, the images are transferred line by line using the dual buffer.

By the way, the printer engine 606 prints images in sequence of RGB points. Therefore, when the user instructs to print the image in another format such as line sequential or surface sequential, it is necessary to perform scanning conversion. This is done when reading images from the dual port rams 205, 206.

The scanning conversion at the time of printing will be described below.

First, when the point-sequential YCrCb image data is sent from the server process 107, there is no need to perform scanning conversion. The point-sequential YCrCb image data is sent to the printer 104, converted into a point-sequential PGB by the printer color conversion unit 601 and printed.

Next, when the line-sequential YCrCb image data is sent, when the image data is read, it is read for each image. That is, Y, which is the first color of the first pixel, then Cr, which is the second color of the first pixel, and then Cb, which is the third color of the first pixel, are read out. Next, Y, which is the first color of the second pixel, then Cr, which is the second color of the second angle, is read, and then Cb, which is the third color of the second pixel, is read. By reading out in the same manner, the line-sequential YCrCb can be converted from an image to a point-sequential YCrCb image.

The image data of this point-sequential YCrCb is sent to the printer 104, converted into point-sequential RGB by the printer color conversion unit 601 and printed.

Next, the scanning conversion when the surface-sequential YCrCb image is transferred will be described.

Since it is not possible to convert from a surface-sequential YCrCb image to a point-sequential YCrCb at one time, the image data is temporarily stored in the hard disk 212.

Then, the film stored in the hard disk 212 is seekd, read out in order of points of YCrCb, and written to the dual port rams 205 and 206 to perform scanning conversion. The point-sequential YCrCb image data is sent to the printer 104, converted into a point-sequential PGB by the printer color conversion unit 601 and printed.

When a point-sequential YCrCb image encoded by the ADCT method is sent, the coding / decoding circuit 213 decodes the YCrCb image into a point-sequential YCrCb image. This point-sequential YCrCb image is alternately written to the dual port rams 205 and 206 line by line and transferred to the printer 104.

As a result, the image can be compressed and transferred, and the amount of communication can be reduced.

FIG. 14 is an explanatory diagram during prescan and scan operations. Hereinafter, data exchange between the host computer 101, the scanner printer server 102, and the scanner 103 during prescan and scan will be described.

When reading an image from the scanner 103, image size, image position, resolution, format (point-sequential, line-sequential, surface-sequential) edge enhancement, color space (RGB, YCrCb), color (which color to send) , For example G only), level (number of color gradations), coding method (ADCT, unencoded, etc.), bit rate (bit rate at the time of coding), thinning rate at the time of prescan, which file to read, Etc. must be specified.

The client process 106 then instructs the user to specify these parameters. The user makes these specifications and executes a prescan.

Then, the client process 106 communicates with the server process 107 according to the sequence shown in FIG.

In FIG. 14, first, the client process 106 sends a PRESCAN packet consisting of XSIZE, YSIZE, XSTART, YSTART, XSTEP, YSTEP, etc. of the image to the server process 107.

In the server process 107, in order to perform image coding and thinning out at the time of prescan, when a PRESCAN packet is received, the coding method, the bit rate at the time of coding, and the thinning rate are set. The other information is sent from the serial interface 207 to the scanner 103 as a prescan command.

The scanner 103 sets parameters in the image reading unit 305 according to the information of the prescan instruction. If these parameters are set correctly, send OK back to server process 107.

Upon receiving an OK from the scanner 103, the server process 107 sends an OK packet back to the client process 106. If it is not set correctly, the status information is sent back to the server process 107.

When the scanner 103 receives the prescan command, it reads the image line by line from the Video I / F.

At the time of prescan, the timing control circuit 208 of the scanner printer server 102 sets HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and DATA (image data signal) 108 to high impedance. Data is read from DATA (image data signal) 108 in synchronization with HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111 generated by the scanner 103, and dual port ram 205, 206. Write to.

The image data read line by line from the server process 107 and Video I / F is read from the dual port rams 205 and 206 and written to the hard disk 212.

At this time, the image is thinned out according to the thinning rate of XSTEP and YSTEP specified in the PRESCAN packet, and this data is divided or combined into an appropriate size, and a plurality of data tags, the number of bytes of the packet, and the image data are formed. Composes a DATA packet and sends it to client process 106 on host computer 101.

The client process 106 of the host computer 101 extracts the image data thinned from the image packet received from the server process 107 and displays it on the CRT.

When the scanner 103 successfully sends all the images, it sends an OK from the scanner serial interface 301 to the server process 107. Upon receiving an OK from the scanner 103, the server process 107 sends an OK packet to the client process 106.

When the server process 107 sends an OK packet to the client process 106, the client process 106 waits for the next command packet.

The client process 106 receives all the decimated images, displays them on the CRT, and asks the user which area of the image to actually scan. The user specifies which area to actually scan with a pointing device such as a mouse. Then, the client process 106 is instructed to start scanning.

Then, the client process 106 sends a SCAN packet consisting of XSIZE, YSIZE, XSTART, YSTART, etc. of the image to the server process 107.

Upon receiving the SCAN packet, server process 107 sends an OK to client process 106 if this information is set correctly.

The server process 107 reads the image data already read into the hard disk 212 at the time of prescan according to the parameters specified in the SCAN packet. This image data is divided or combined into appropriate sizes, constitutes a plurality of DATA packets consisting of a DATA tag, doubles and numbers of packets, and image data, and is sent to the client process 106 of the host computer 101.

The client process 106 of the host computer 101 takes out the image data received from the server process 107 and writes them to the disk one after another.

When the server process 107 successfully sends all the images, it sends an OK packet to the client process 106.

When the server process 107 sends an OK packet to the client process 106, it waits for the next command packet from the client.

When the client process 106 receives the OK packet from the server process 107, it waits for an instruction from the next user.

FIG. 15 is an explanatory diagram during the printing operation, and the data exchange between the client process 106 of the host computer 101, the scanner printer server 102, and the printer 104 at the time of printing will be described below.

When a user wants to create a document or picture on the host computer 101 using desktop publishing software (hereinafter, DTP software), create data in the page description language format, which is the output data format, or print it. , When you want to print the image data in the raw image data format or the compressed image format, specify whether the image data to be printed is the page description language format or the image data format. Specify the position of the image to be printed, the file name on the host computer 101 that holds the image to be printed, and so on.

The server process 107 determines the data format and determines whether to use the function in the designated printer or the scanner printer server 102.

In addition, parameters such as gamma conversion and masking conversion at the time of printing are usually set to default values, but these can also be changed.

In this case, in FIG. 15, the client process 106 first sends a GAMMA packet to the server process 107 to set the gamma tail when printing the image. If the gamma table is already set, there is no need to send it.

When the server process 107 receives the GAMMA packet, it sends a gamma setting command to the printer 104 when the second byte of the GAMMA packet indicates the printer, the scanner 103 when indicating the scanner, and the printer 104.

The printer 104 sets the LUT of the printer gamma conversion unit 602 according to the parameters of the gamma setting instruction. If it can be set normally, OK is sent back to the server process 107.

Upon receiving the scanner OK, the server process 107 sends an OK packet back to the client process 106.

The client process 106 then sends a MASKING packet to the server process 107 to set the masking table for image printing. If the masking table is already certified, you do not need to send it.

Upon receiving the MASKING packet, the server process 107 sends a masking authorization instruction to the printer 104.

The printer 104 sets the parameters of the masking conversion unit 603 according to the parameters of the masking certification instruction. If it can be set successfully, send OK back to server process 107.

Upon receiving an OK from the printer 104, the server process 107 sends an OK packet back to the client process 106.

As described above, when the parameters for gamma conversion and masking conversion are set, the client process specifies whether the data to be printed is in the page description language format, raw image format, or compressed image format, specifies the printer, and XSIZE of the image. , YSIZE, XSTART, YSTART, PAGE, etc. Send a PRINT packet to server process 107.

Upon receiving the PRINT packet, server process 107 initiates a connection with the specified printer. If the printer does not have the page description language interpretation function and the data in the page description language format is received, the processing is performed inside the scanner printer server 102. The same applies to compressed data.

Here, as described above, the discussion will proceed in the case of a printer using Video I / F when the printer has no function.

Upon receiving the PRINT packet, the server process 107 sends a print instruction from the serial interface 207 to the printer 104.

The printer 104 sends OK back to the server process 107 when the print instruction information is set correctly.

When the server process 107 receives the OK from the printer, it sends the OK packet back to the client process 106.

Upon receiving the OK packet, the client process 106 reads the image data (including the page description language format, the raw image data format, the compressed image data format, etc.) from the specified file. The client process 106 divides or combines the read image data into appropriate sizes to form a plurality of DATA packets consisting of a DATA tag, the number of bytes of the packet, and image data, and sends the read image data to the server process 107.

The server process 107 extracts image data from the image packet received from the client process 106 of the host computer 101. If the image data is in the page description language format, the page description language interpreter is started and bitmap expansion is performed. In the case of the compressed image data format, the decompression process using the decompression circuit is started to perform bitmap expansion. The bitmap-developed data and the raw image data are sequentially sent from the VIDeo I / F to the printer 104 and printed.

At the time of printing, the timing control circuit 208 of the scanner printer server 102 uses HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and DATA (image data signal) the image data synchronized with these. ) 108 is output, and the printer 104 reads the data to be printed from the DATA (image data signal) 108 signal in synchronization with this and prints the data.

When the printer 104 prints all the images successfully, it sends an OK from the print serial interface 401 to the server process 107. Upon receiving an OK from the printer 104, the server process 107 sends an OK packet to the client process 106.

When the server process 107 sends an OK packet to the client process 106, it waits for the next command packet from the client. When the client process 106 receives the OK packet from the server process 107, it waits for an instruction from the next user.

FIG. 16 is an explanatory diagram when an error occurs during printing, and the exchange of data between the host computer 101, the scanner printer server 102, and the printer 104 at the time of printing will be described below according to the diagram.

Similar to the above printing, the client process 106 sets the gamma table and masking table at the time of image printing.

Next, the client process 106 specifies whether the data to be printed is a page description language format, a raw image format, or a compressed image format, specifies a printer, and a PRINT packet consisting of XSIZE, YSIZE, XSTART, YSTART, PAGE, etc. of the image. To server process 107.

Upon receiving the PRINT packet, server process 107 initiates a connection with the specified printer. If the printer does not have the page description language interpretation function and the data in the page description language format is received, the processing is performed inside the scanner printer server 102. The same applies to compressed data.

Again, as mentioned earlier, we will proceed with the case of a printer using Video I / F when the printer has no function.

Upon receiving the PRINT packet, the server process 107 sends a print instruction from the serial interface 207 to the printer 104.

When the value of the parameter of the print instruction is invalid, an abnormality such as being unable to set, or an error such as a piece of paper occurs, the printer 104 sends back status information indicating the error status to the server process 107.

When the server process 107 receives the status information from the scanner, it converts the status information into a status packet and sends it back to the client process 106.

When the client process 106 receives the STATUS packet, it outputs an appropriate message to the user according to its status to notify that an error has occurred.

If an error such as a paper jam occurs during printing, the printer CPU 402 immediately interrupts the printing operation and transmits the error status information from the printer serial interface 401 to the server process 107.

When the server process 107 receives the status information from the printer 104, it sends this status information as a STATUS packet to the client process 106 and waits for the next command.

When the client process 106 receives the STATUS packet, it outputs an appropriate message to the user according to its status to notify that an error has occurred.

FIG. 17 is an explanatory diagram during operation when printing a plurality of identical images. Hereinafter, data exchange between the host computer 101, the scanner printer server 102, and the printer 104 at the time of printing will be described with reference to the drawings.

On the host computer 101, if the image to be printed is in the page description language format, the user holds the file name, if it is in the raw image data format, compressed image data format, etc., its size, and the image to be printed. Specify the location of, the file name on the host computer 101 that holds the image to be printed, and so on. At this time, it is assumed that parameters such as gamma conversion and masking conversion at the time of printing have already been set.

In FIG. 17, first, the client process 106 specifies whether the page description language format of the data to be printed is the raw image format or the compressed image format, specifies the printer, and prints XSIZE, YSIZE, XSTART, YSTART, and how many images. A PRINT packet consisting of a PAGE indicating the above is sent to the server process 107.

Upon receiving the PRINT packet, server process 107 initiates a connection with the specified printer. If the printer does not have a page description language interpretation function and receives data in the page description language format, the scanner printer server 102 performs expansion processing for the page description language. The same applies to compressed data.

Again, as mentioned earlier, we will proceed with the case of a printer using Video I / F when the printer has no function.

Upon receiving the PRINT packet, the server process 107 sends a print instruction from the serial interface 207 to the printer 104.

The printer 104 sends OK back to the server process 107 if the print instruction information is set correctly.

Upon receiving an OK from the scanner, the server process 107 sends an OK packet back to the client process 106.

When the client process 106 receives the OK packet, it reads the image from the specified file. The client process 106 divides or combines the read image data into appropriate sizes to form a plurality of DATA packets consisting of a DATA tag, the number of bytes of the packet, and image data, and sends the read image data to the server process 107.

The server process 107 extracts image data from the image packet received from the client process 106 of the host computer 101. If the image data is in the page description language format, start the page description language interprinter and perform bitmap expansion. In the case of the compressed image data format, the decompression process using the decompression circuit is started to perform bitmap expansion. The bitmap-developed data and the raw image data are sequentially sent from the Video I / F to the printer 104 for printing. At the same time, the image data is stored in the hard disk 212.

When the printer 104 prints the first image normally, OK is sent from the printer serial interface 401 to the server process 107.

When the server process 107 receives OK from the printer 104, the server process 107 reads the already written image from the hard disk 212 from the second image, and sequentially prints the image from the Video I / F to the printer 104.

When the server process 107 prints the number of PAGEs specified in the PRINT packet, it sends an OK packet to the client process 106 to notify that the print was successful. Also, the image stored at this time is deleted.

When the server process 107 sends an OK packet to the client process 106, it waits for the next command packet from the client.

The client process 106 sends all the images, and when it receives an OK packet from the server process 107, it waits for an instruction from the next user.

Next, another embodiment of the present invention will be described. In FIG. 21, first, the client process 106 sends a SCAN packet including XSIZE, YSEZE, XSTART, YSTART, XSTEP, YSTEP, etc. of the image to the server process 107. In the server process 107, each parameter of the image processing of the server is set by the instruction in the SCAN packet, and the instruction related to the image size is sent from the serial interface 207 to the scanner 103.

The scan 103 sets parameters in the image reading unit 305 according to the information of the scan command. If these parameters are set correctly, send OK back to server process 107.

Upon receiving an OK from the scanner, the server process 107 sends an OK packet back to the client process 106. If it is not set correctly, it will be sent back to the status information server process 107.

When the scanner 103 receives the scan command, it reads the image line by line from the Video I / F.

At the time of scanning, the timing control circuit 208 of the scanner printer server 102 sets HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and DATA (image data signal) 108 to high impedance, and the scanner Data is read from DATA (image data signal) 108 in synchronization with HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111 that generate 103, and to dual port ram 205, 206. Write.

The server process 107 reads the image data read line by line from the Video I / F from the dual port rams 205 and 206 and writes them to the hard disk 212.

At this time, if there is an instruction to transfer the thinned data from the computer, the image is thinned according to the thinning rate of XSTEP and YSTEP specified in the SCAN packet at the same time as writing to the dual port rams 205 and 206, and this data is appropriately extracted. It is divided into sizes or combined to form a plurality of DATA packets consisting of a DATA tag, the number of bytes of the packet, and image data, and sent to the client process 106 of the host computer 101.

The client process 106 of the host computer 101 extracts the image data thinned from the image packet received from the server process 107 and displays it on the CRT.

When the scanner 103 successfully sends all the images, it sends an OK from the scanner serial interface 301 to the server process 107.

Upon receiving an OK from the scanner 103, the server process 107 sends an OK packet to the client process 106.

When the server process 107 sends an OK packet to the client process 106, it waits for the next command packet from the client process 106. The client process 106 receives all the decimated images, displays them on the CRT, and asks the user which area of the image to actually scan. The user specifies which area is actually needed by a pointing device such as a mouse.

Then, the designated area is instructed to the client process 106. Then, the client process 106 sends a CUT packet consisting of XSIZE, YSIZE, XSTART, YSTART, etc. of the image to the server process 107.

When server process 107 receives a CPU packet and this information is set correctly, it sends an OK back to client process 106.

The client process 106 then sends the page description language created by another application program to the server process 107.

Server process 107 expands the page description language with interpreter 214 and creates bitmaps of characters and graphics. Then, the image data read from the scanner and held in the image storage means is read from the designated area of the CUT packet at the location specified in the page description language, and synthesized in the above-mentioned bitmap. Then, the server process 107 transfers the composite image data to the printer side and prints it. If there is an instruction for image processing in the page description language, the processing is added at the same time as reading the image data from the image storage means.

When the server process 107 successfully sends all the images to the printer, it sends an OK packet to the client process 106. If the client process 106 instructs continuous printing, the server process transfers the bitmap-expanded image data to the printer.

When the server process 107 sends an OK packet to the client process 106, it waits for the next command packet from the client.

When the client process 106 receives the OK packet from the server process 107, it waits for an instruction from the next user.

FIG. 18 shows the packet configuration.

(a) is a PRESCAN packet, (b) is an SCAN packet, and (c) is a PRINT packet.

The first byte of each packet is a tag that represents what the packet is. For example, PRESCAN is 1 to indicate prescan. SCAN is 2, indicating to scan.

SCANNERNAME and PRINTERNAME specify the device name for inputting / outputting images.

DATATYPE specifies whether the image data is in the page description language format, the compressed image format, or the raw image data format.

XSIZE indicates the size of the 2-byte image in the X direction, and YSIZE indicates the size of the 2-byte image in the Y direction.

XSTART indicates the X-direction scan and print start position of the 2-byte image, and YSTART indicates the Y-direction scan and print start position of the 2-byte image.

XZOOM indicates the X-direction scan and print resolution of the 1-byte image, and YZOOM indicates the Y-direction scan and print resolution of the 1-byte image.

FORMAT indicates an image scanning method, and is specified as 1 for point sequence, 2 for line sequence, and 3 for surface sequence.

EDGE indicates the degree of edge enhancement and smoothing, 16 to 1 is specified as edge enhancement, and -1 to -16 is specified as smoothing.

COLORTYPE indicates the color space of the image, and is specified as 1 for RGB and 2 for YCrCb. In the case of RGB, the first color is called R, the second color is called G, and the third color is called B. In the case of YCrCb, the first color is Y, the second color is Cr, and the third color is B. Let's call it Cb.

COLOR indicates which of the colors in the image to send. For example, if only the first color is used, the second bit is set, if only the second color is used, the first bit is set, and if only the third color is used, the 0th bit is set to 1. For example, if COLOR and TYPE are RGB and all RGB colors are sent, it will be 7, and if two colors R and B are sent, it will be 5 (1st color = 4, 3rd color = 1). ..

Similarly, if the COLORTYPE is YCrCb and only Y is sent, it will be 4.

LEVEL consists of 2 bytes, the first 4 bits indicate the number of gradations of the first color, the next 4 bits indicate the number of gradations of the second color, and the next 4 bits indicate the number of gradations of the third color. Shown. The last 4 bits are undefined. The number of these gradations is specified by two exponents, such as 256 gradations for 8 and 64 gradations for 6.

CODE indicates the coding method, and is specified as 0 when not coding and 1 when coding by ADCT.

BITRATE indicates the coding rate of coding, 6 indicates that it is encoded at a compression rate of 1/6, and 12 indicates that it is encoded at a compression rate of 1/12.

XSTEP and YSTEP specify how much images are thinned out during prescan. For example, when sending an image every 5 pixels vertically and horizontally, XSTEP = 5 and YSTEP = 5. If it is not thinned out, XSTEP = 0 and YSTEP = 0.

UCR indicates α at the time of black formation.

BI-LEVEL indicates the binarization method, and 0 indicates that the print engine 606 is a multi-value printer and does not perform binarization. 1 is the fatning pattern of the dither method, 2 is the Bayer pattern of the dither method, 3 is the simple binarization method, and 4 is the error diffusion method.

THRESHOLD indicates the binarization threshold (0 to 255) of the simple binarization method.

PAGE shows the number of pages at the time of printing.

(D) in FIG. 18 shows an OK packet. The OK packet is only a 1-byte OK tag.

(E) of FIG. 18 is a GAMMA packet, and the S / P of the second byte indicates whether to set in the gamma table of the scanner 103 or the printer 104. After that, the gamma table consists of 768 bytes for 256 * 3 colors.

(F) in FIG. 18 is a MASKING packet, which consists of a masking tag and a masking parameter consisting of a 2-byte fixed-point number.

Figure 18 (g) is a STATUS packet, which consists of a status tag, a number of statuses, and a status.

(H) in FIG. 18 is a DATA packet, which is composed of a data tag, the number of image data to be followed, and image data.

(I) in FIG. 18 is an ESC packet, which is a sequence in which the first byte starts with ESC, and is expanded to a bitmap or byte map image by the interpreter 214. This is equivalent to the ESC sequence of a normal printer.

The configuration of commands from the scan printer server 102 to the scanner 103 and the printer 104 will be described below.

The command configurations such as the pre-scan command, scan command, status information, gamma setting command, and masking setting command are also communicated in the same format as in FIG.

FIG. 19 shows the configuration of instructions between the scanner printer server and the scanner printer. (a) is a prescan command, (b) is a scan command, and (c) is a print command.

The first byte of each packet is a tag that represents what the packet is. For example, PRESCAN is 1 to indicate prescan. SCAN is 2, indicating to scan.

XSIZE indicates the size of the 2-byte image in the X direction, and YSIZE indicates the size of the 2-byte image in the Y direction.

XSTART indicates the X-direction scan and print start position of the 2-byte image, and YSTART indicates the Y-direction scan and print start position of the 2-byte image.

XZOOM indicates the X-direction scan and print resolution of the 1-byte image, and YZOOM indicates the Y-direction scan and print resolution of the 1-byte image.

FORMAT indicates an image scanning method, and is specified as 1 for point sequence, 2 for line sequence, and 3 for surface sequence.

EDGE indicates the degree of edge enhancement and smoothing, 16 to 1 is specified as edge enhancement, and -1 to -16 is specified as smoothing.

COLORTYPE indicates the color space of the image, and is specified as 1 for RGB and 2 for YCrCb. In the case of RGB, the first color is called R, the second color is called G, and the third color is called B. In the case of YCrCb, the first color is called Y, the second color is called Cr, and the third color is called Cb.

COLOR indicates which of the colors in the image to send. For example, if only the first color is used, the second bit is set, if only the second color is used, the first bit is set, and if only the third color is used, the 0th bit is set to 1. For example, if COLORTYPE is RGB and all RGB colors are sent, it will be 7. Also, when sending two colors R and B, it becomes 5 (1st color = 4, 3rd color = 1). Similarly, if the COLORTYPE is YCrCb and only Y is sent, it will be 4.

LEVEL consists of 2 bytes, the first 4 bits indicate the number of gradations of the first color, the next 4 bits indicate the number of gradations of the second color, and the next 4 bits indicate the number of gradations of the third color. Shown. The last 4 bits are undefined.

The number of these gradations is specified by an exponent of 2, such as 256 gradations for 8 and 64 gradations for 6. CODE indicates the coding method, and is specified as 0 when not coding and 1 when coding by ADCT.

UCR indicates α at the time of black formation.

BI-LEVEL indicates the binarization method, and 0 indicates that the print engine 606 is a multi-value printer and does not perform binarization. 1 is the fatning pattern of the dither method, 2 is the Bayer pattern of the dither method, 3 is the simple binarization method, and 4 is the error diffusion method.

THRESHOLD indicates the binarization threshold (0 to 255) of the simple binarization method.

PAGE shows the number of pages at the time of printing.

(D) in Fig. 19 is a type of status information and indicates OK. OK is just a 1-byte OK tag.

FIG. 19 (e) is a gamma setting instruction, and the S / P of the second byte indicates whether to set the gamma table of the scanner 103 or the printer 104. After that, the gamma table consists of 768 bytes for 256 * 3 colors.

(F) in FIG. 19 is a masking setting instruction, which consists of a masking tag and a masking parameter consisting of a 2-byte fixed point number.

(G) in FIG. 19 is status information, which consists of a status tag, a number of statuses, and a status.

(H) in FIG. 19 is a copy instruction, which is only a 1-byte copy tag.

Next, the copy operation using the scanner 103 and the printer 104 will be described.

In the case of copying, when the user presses the copy button on the scanner 103 operation panel 306, the scanner control circuit sends a copy command from the scanner serial interface 301 to the scanner printer server 102.

Upon receiving the copy instruction, the scanner printer server 102 sends a scan instruction to the scanner 103 and a print instruction to the printer 104. At this time, parameters such as masking suitable for copying are set.

When the scanner / printer server 102 receives the copy command, the scanner / printer server 102 has high impedance of HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, COLOR (clock signal) 111, and DATA (image data signal) 108.

When the scanner 103 receives a scan command, the scanner control circuit of the scan 103 sets the print start position of the operation panel 306, and the scanner control circuit of the scanner 103 sets the print start position of the operation panel 306, the print image size, and the like. Based on this, the image is read, and HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and the image data synchronized with them are output.

In the printer timing control circuit 404, image data is received in synchronization with HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, and CLOCK (clock signal) 111 from the scanner 103, and copying is performed by printing. ..

At the time of copying, the timing control circuit of the scanner / printer server 102 is such that 208 sets each signal line of HSYNC (horizontal synchronization signal) 110, VSYNC (vertical synchronization signal) 109, CLOCK (clock signal) 111, and DATA (image data signal) 108. Make it high impedance.

When copying is performed, the image cannot be scanned or printed remotely. Therefore, when the server process 107 receives the scan packet or print packet from the client process 106, it indicates that the image is being copied. Sends a packet to client process 106 to inform the user that it cannot scan or print.

Also, if a remote image scan or print is being performed, copying cannot be performed. Therefore, the scanner CPU 302 displays on the operation panel 306 that the scanner and the printer are in operation while the scanner and the printer are in operation, and prevents copying from being accepted.

In the embodiment of the present invention, the case where the bus type Ethernet (R) 105 is used for the network has been described, but the network can be easily applied to any network.

Further, in the embodiment of the present invention, the case where serial communication is used to communicate data such as commands, parameters, and errors between the scanner printer server 102, the scanner 103, and the printer 104 has been described. Any two-way communication interface can be used.

Further, in the embodiment of the present invention, serial communication for communicating data such as commands, parameters, and errors between the scanner printer server 102, the scanner 103, and the printer 104 is used, and a video interface is used for communicating image data. It is also possible to communicate information such as commands, parameters, errors, and image data on the same communication path using an interface that enables bidirectional communication such as SCSI and GPIB, regardless of these communication interfaces. ..

Further, in the embodiment of the present invention, when the image is in the point-sequential YCrCb format, the image is encoded by the ADCT coding method and sent, but the image is not bound by the ADCT coding method, and an arbitrary coding method can be used. Can be used. As a result, images other than the point-sequential YCrCb format can be encoded, and the images can be compressed and transmitted.

Further, in the embodiment of the present invention, the dual port ram for one line is used, but the speed is not limited to this, and the memory for a plurality of lines or one screen can be provided to achieve higher speed.

Further, in the embodiment of the present invention, the image is thinned out and sent at the time of prescan, and the image is sent without thinning out at the time of the main scan, but when the color image is prescanned, only (1) a single color component is sent. (2) Thin out and send. (3) Encode and send. It is also possible to send a combination of (4) lowering the number of gradations of the image and sending (5) lowering the resolution of the image.

Further, in the embodiment of the present invention, an image is read at the time of prescan, and the image data is stored in the hard disk 212 and at the same time thinned out and transferred. Then, at the time of this scan, the image on the hard disk 212 was read out and transferred. However, at the time of prescan, the image is not stored in the hard disk, and only (1) monochromatic component is sent directly. (2) Thin out and send. (3) Encode and send. (4) Send by lowering the number of gradations of the image (5) Send by lowering the resolution of the image.

Then, at the time of the main scan, it is possible to scan and transfer the image again.

Further, in the embodiment of the present invention, when the image is read, scanned and converted surface-sequentially and transferred, the scan engine 505 scans the image three times. However, it is also possible to read the image only once, store the image data in the hard disk 212, and read the image of the hard disk 212 three times. As a result, only one mechanical scan is required, and the speed can be increased.

It is also possible to store in the hard disk 212 and at the same time perform scanning conversion of the first color and read the remaining two times from the hard disk.

Further, in the embodiment of the present invention, the binarization unit 605 performs binarization of the image for the binarization print engine. However, it is not limited to the binary print engine, and in the case of the N value print engine, it can be easily dealt with by providing the N value conversion unit.

In addition, the scanner printer server is provided with a storage means for storing the scanned image, and the image is temporarily stored in this storage means at the time of prescan, and the stored image is read out empty at the time of the main scan, so that two conventional scans are required. It was possible to do it once, and it was possible to read images at high speed.

When printing a plurality of sheets, the image is stored in the storage means when the first one is printed, and the image is transferred only once by reading from the storage means and printing from the second sheet. All I had to do was to enable high-speed printing.

Also, at the time of prescan, the color image is sent (1) only the single color component is sent. (2) Thin out and send. (3) Encode and send. By sending a combination of (4) lowering the number of gradations of the image and sending (5) lowering the resolution of the image and sending it, the image can be compressed and sent, which has the great advantage of reducing the amount of communication. ..

In addition, by providing a two-way communication path, it has become possible to prevent copying from being accepted when the scanner printer is being used from the network, and to prevent the scanner printer from being used from the network when copying. ..

<figref num="1">It is a system block diagram which carried out the present invention.</figref><figref num="2">It is a block diagram of a scanner printer server.</figref><figref num="3">It is a block diagram of a scanner.</figref><figref num="4">It is a block diagram of a printer.</figref><figref num="5">It is a block diagram of the image reading part 305.</figref><figref num="6">It is a block diagram of the print part 405.</figref><figref num="7">It is explanatory drawing of image scan and print.</figref><figref num="8">It is a detailed explanatory diagram of the timing. ]</figref><figref num="9">It is an explanatory diagram of the dual port ram operation at the time of scanning and printing.</figref><figref num="10">It is an explanatory diagram of the dual port ram operation at the time of scanning.</figref><figref num="11">It is an explanatory diagram of the dual port ram operation at the time of scanning.</figref><figref num="12">It is an explanatory diagram of dual port ram operation at the time of printing.</figref><figref num="13">It is an explanatory diagram of dual port ram operation at the time of printing.</figref><figref num="14">It is explanatory drawing at the time of a pre-scan and a scan operation.</figref><figref num="15">It is explanatory drawing at the time of printing.</figref><figref num="16">It is explanatory drawing when an error occurs at the time of a print operation.</figref><figref num="17">It is explanatory drawing at the time of operation at the time of printing a plurality of identical images.</figref><figref num="18">It is explanatory drawing of a packet.</figref><figref num="19">It is explanatory drawing of the instruction between a scanner printer server and a scanner printer.</figref><figref num="20">It is explanatory drawing of the communication between a scanner, a printer and a scanner printer server.</figref><figref num="21">It is explanatory drawing of the operation which scans and expands PDL data.</figref>

Code description

101 Host Computer 102 Scanner Printer Server 103 Scanner 104 Printer 105 Ethernet (R) 106 Client Process 107 Server Process