Image forming device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an image forming apparatus that forms an image by electrophotographic technology.

【0002】

[Conventional technology]

Conventionally, in an image forming apparatus using electrophotographic technology such as a printer, a facsimile, and a copier, a photoconductor roller as an image carrier and a developing roller for developing an electrostatic latent image formed on the photoconductor roller are images. It is provided in the forming part. And especially in recent years, accurate color superimposition of toner images of each color is required for color print output, and in order to obtain a stable image, it is accurate so that there is no speed fluctuation such as rotation unevenness of the developing roller. Drive transmission is becoming more important.

【0003】

One of the causes of uneven drive rotation of the developing roller is that there is a gap between the meshing gears and the tooth surfaces of the gears. That is, it is usual to provide a gap (backlash) between the meshing gears so that a smooth meshing motion can be performed, and there is a fluctuation in the drive transmission torque or a sudden change in the rotation speed of the motor. If this happens, the tooth surface and the tooth surface that are engaged and contacted to transmit power will temporarily separate from each other in the backlash space, and power will not be transmitted temporarily. For this reason, intermittent fluctuations in the transmission rotation speed occur, and as a result, the rotation speed of the developing roller fluctuates, causing rotation unevenness.

【0004】

In order to suppress such rotational unevenness of the developing roller, it is very important in design that the gear, which is a power transmission means, is not used more than necessary. Furthermore, it is especially important not to use intermediate gears just to fill the distance between the shafts.

【0005】

The image forming apparatus is also provided with, for example, a transmission system for feeding paper. When rotation unevenness occurs in this rotation transmission system, accurate paper feed cannot be reproduced and the feed direction pitch expands and contracts. Especially in an image forming apparatus that performs color printing, color shift occurs and color reproducibility occurs. Becomes worse.

【0006】

Next, the drive transmission technology of the conventional photoconductor roller and the developing roller will be described with reference to FIGS. 4 and 5.

【0007】

FIG. 4 is a perspective view showing the main parts of the power transmission mechanism in the conventional photoconductor roller and the developing roller, and FIG. 5 is a front view showing the main parts of the power transmission mechanism in the conventional photoconductor roller and the developing roller.

【0008】

The power transmission means are an array of drive transmission means using several gears, pulleys, and other drive transmission means from the development roller drive motor 28 called the development roller drive series to the development roller (second roller) 11, and the photosensitivity. It consists of two drive sequences called a body roller drive sequence, which is an array of drive transmission means from the photoconductor drive motor 29 to the photoconductor roller (first roller) 7.

【0009】

As shown in the figure, a developing roller drive motor 28 and a photoconductor drive motor 29 are attached to the plate 30. The rotating shaft of the developing roller drive motor 28 penetrates a hole formed in the plate 30, and a developing motor gear 32 is fixed to the tip of the rotating shaft. Further, a developing roller drive gear 33 is rotatably attached to the plate 30. Further, the intermediate gear 35A is rotatably attached to the plate 30 so as to mesh with the developing motor gear 32 and the developing roller drive gear 33. The developing roller 11 that develops the electrostatic latent image of the photoconductor roller 7 is connected to the developing roller drive gear 33 via a transmission connection device (not shown).

【0010】

On the other hand, the rotation shaft of the photoconductor drive motor 29 is also arranged so as to penetrate the hole formed in the plate 30, and the photoconductor motor gear 34A is fixed to the tip thereof. Further, a photoconductor drive gear 36A is rotatably attached to the plate 30, and an intermediate gear 35B is rotatably attached to the plate 30 so as to mesh with the photoconductor motor gear 34A and the photoconductor drive gear 36A. The photoconductor roller 7, which is an image carrier, is connected to the photoconductor drive gear 36A via a transmission connection device (not shown).

【0011】

Here, the outer diameters of the developing roller 11 and the photoconductor roller 7 are reduced in order to reduce the size of the image forming apparatus, and the diameters of the developing roller drive gear 33 and the photoconductor drive gear 36A are also reduced accordingly.

【0012】

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional technique, there is a limit to compactly arranging two drive series on the same plane, and it is not possible to arrange a shaft that supports the gear on a rotating gear. For this reason, the developing roller drive series and the photoconductor roller drive series are driven separately by the high-cost developing roller drive motor 28 and the photoconductor drive motor 29.

【0013】

Further, since it is necessary to attach these two developing roller drive motors 28 and the photoconductor drive motor 29 so as not to interfere with each other, a driving force is applied to the developing roller 11 and the photoconductor roller 7 from the output shafts of the respective motors. Each drive series cannot be placed in the shortest position for transmission. For this reason, it was necessary to use intermediate gears 35A and 35B, which are prone to uneven rotation, to make a detour.

【0014】

As described above, in the conventional image forming apparatus, it is necessary to provide a developing roller driving motor 28 for driving the developing roller 11 and a photoconductor driving motor 29 for driving the photoconductor roller 7, which increases the cost. Was there. Further, since the developing roller drive motor 28 and the photoconductor drive motor 29 must be mounted so as not to interfere with each other to drive the developing roller 11 and the photoconductor roller 7, rotation unevenness is likely to occur and space is required. It was necessary to use intermediate gears 35A and 35B, which deteriorate in efficiency.

【0015】

Therefore, the present invention makes it possible to drive both the developing roller and the photoconductor roller with a single motor without using an intermediate gear, improving space efficiency and suppressing the occurrence of rotational unevenness, and obtaining optimum development. The purpose is to provide an image forming apparatus to be used.

【0016】

[Means for solving problems]

The present invention relates to an image forming apparatus including a drive mechanism for synchronously rotating a first roller and a second roller paired with the first roller, wherein the drive mechanism includes a common motor having a motor pulley on an output shaft and the above. An endless first belt wound around a motor pulley, a first relay pulley and a second relay pulley rotatably arranged including a driven peripheral surface in a loop of the first belt, and the above. The first relay pulley includes a second belt for transmitting the rotation of the first relay pulley to the first roller, and the first relay pulley includes a drive pulley for transmitting the rotation to the first roller. The relay pulley 2 includes a drive gear for transmitting rotation to the second roller, and the first roller includes a drive pulley around which the second belt rotates and drives the rotation, and the first relay The pulley and the first roller are connected by the first belt, the second roller is provided with a drive gear, and the second relay pulley and the second roller are connected by a gear train. It is characterized by.

【0017】

In such a configuration, for example, a developing roller and a photoconductor roller can be driven by a single motor, and since an intermediate gear does not intervene, it is possible to prevent uneven rotation of each roller.

【0018】

BEST MODE FOR CARRYING OUT THE INVENTION

The invention according to claim 1 is an image forming apparatus including a drive mechanism for synchronously rotating a first roller and a second roller paired with the first roller, wherein the drive mechanism is shared with a motor pulley on an output shaft. Motor, an endless first belt wound around the motor pulley, and a first relay pulley and a second relay pulley rotatably arranged so as to include a driven peripheral surface in a loop of the first belt. The relay pulley includes a relay pulley and a second belt for transmitting the rotation of the first relay pulley to the first roller, and the first relay pulley is a drive pulley that transmits the rotation to the first roller. The second relay pulley is provided with a drive gear for transmitting rotation to the second roller, and the first roller is provided with a drive pulley for rotating and driving the second belt. The first relay pulley and the first roller are connected by the first belt, and the second roller includes a drive gear and gears between the second relay pulley and the second roller. There is an image forming device characterized by being connected by rows, and it has an effect that, for example, two rollers can be driven by a single motor and rotation unevenness of each roller can be prevented.

【0019】

In the invention according to claim 2, the first roller is a photoconductor roller that is an image carrier, and the second roller is a developing roller that develops an electrostatic latent image formed on the photoconductor roller. The image forming apparatus according to claim 1, wherein the image forming apparatus has an action of optimizing toner development on a photoconductor roller without causing uneven rotation of the developing roller.

【0020】

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.

【0021】

FIG. 1 is a schematic view showing the configuration of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing a drive transmission mechanism between a photoconductor roller and a developing roller in the image forming apparatus of FIG. 1, and FIG. 3 is a perspective view. It is a front view which shows the drive transmission mechanism between a photoconductor roller and a developing roller in the image forming apparatus of FIG.

【0022】

The image forming apparatus according to the embodiment of the present invention is a printer for printing on the fed paper. As shown in FIG. 1, the printer 1 constituting the image forming apparatus in the present embodiment feeds the supply cassette 2 for storing the output paper 3 and the output paper 3 in the supply cassette 2 one by one. A roller 4 and a transport roller 5 for transporting the output paper 3 fed by the paper feed roller 4 to the printing unit on the downstream side in the transport direction are provided. A process unit 6 is arranged downstream of the transport roller 5 to facilitate replacement of consumable parts by integrally configuring main parts for image formation and detachably supporting the printer 1. The process unit 6 includes a fixed shaft 8 as a first conductive member provided on the side wall thereof and a photoconductor roller 7 rotatably supported around the fixed shaft 8 as an image carrier.

【0023】

Around the photoconductor roller 7, a high voltage is applied from a high-voltage power source (not shown) to uniformly charge the peripheral surface of the photoconductor roller 7, a charger 9, and a laser beam corresponding to image data. A laser scanning unit 10 that irradiates an exposure beam to form an electrostatic latent image on the peripheral surface of the photoconductor roller 7, a developing roller 11 that develops the electrostatic latent image with toner, and a developing toner image that is transferred to the surface of the output paper 3. A transfer roller 16 to be transferred, a cleaning blade 17 for removing the toner 13 remaining on the photoconductor roller 7 that could not be transferred to the output paper 3, and a toner storage chamber 18 for storing the toner 13 are arranged.

【0024】

The developing roller 11 is rotatably supported on the side wall of the process unit 6, and pushes the toner 13 supplied by the replenishing roller 12 to the developing blade 15 fixed to the blade mounting plate 14 of the process unit 6. Triboelectrically charged to a uniform thin layer state by pressure. Then, by applying a negative potential to apply a negative charge to the toner 13 on the surface in advance, the toner 13 is attached only to the portion where the exposure light is applied to the photoconductor roller 7 and the charge is lost, and the toner image is displayed. Perform negative-positive process development to form.

【0025】

The transfer roller 16 is rotatably arranged in the printer 1 and transfers the developed toner image on the peripheral surface of the photoconductor roller 7 on the surface of the output paper 3 conveyed by the transfer roller 5. Further, the toner storage chamber 18 is provided with an agitator 19 that agitates the built-in toner 13 by rotating and conveys it to the replenishment roller 12.

【0026】

Further, downstream of the process unit 6, a fixing device 20 provided with a heat roller 21 and a pressure roller 22 for heat fixing, and a paper ejection roller 23 for discharging the output paper 3 from the fixing device 20 to the outside of the machine. , A paper ejection tray 25 for loading the printed paper 24 is provided. Reference numeral 26 denotes a display unit provided on the surface of the main body of the printer 1 to convey information such as the operating status of the printer 1 to the user.

【0027】

Here, the drive transmission mechanism between the photoconductor roller 7 and the developing roller 11 will be described with reference to FIGS. 2 and 3.

【0028】

As shown in the figure, a shared motor 37 is attached to the plate 30, and the rotating shaft of the shared motor 37 penetrates a hole formed in the plate 30 and protrudes from the plate 30, and a motor pulley 34 is fixed to the tip thereof. Further, the plate 30 holds one end side of the photoconductor roller 7 and the developing roller 11 in the axial direction by a bearing (not shown), and the photoconductor roller 7 and the developing roller 11 have a photoconductor roller drive pulley 36 and a photoconductor roller drive pulley 36. The developing roller drive gear 33 is integrally attached. Further, the first relay pulley 38A and the second relay pulley 38B are rotatably arranged on the plate 30.

【0029】

The first relay pulley 38A is a so-called stepped type with a large pulley 38A-1 and a small pulley 38B-2 coaxially arranged therein, and the second relay pulley 38B is also a gear 38B-1 and a pulley 38B-. It is a stepped type with 2. Then, the belt 39A is wound around the motor pulley 34, the large pulley 38A-1 of the first relay pulley 38A, and the pulley 38B-2 of the second relay pulley 38B.

【0030】

The gear 38B-1 of the second relay pulley 38B is arranged so as to mesh with the developing roller drive gear 33, and the developing roller 11 is rotationally driven by the rotation of the second relay pulley 38B. Further, the belt 39B is circulated between the small pulley 38A-2 of the first relay pulley 38A and the photoconductor roller drive pulley 36 provided on the photoconductor roller 7, and the rotation from the first relay pulley 38A is the photoconductor roller. It is transmitted to 7.

【0031】

The outer peripheral surfaces of the motor pulley 34, the large and small pulleys 38A-1, 38A-2 of the first relay roller 38A, the pulley 38B-2 of the second relay roller 38B, and the photoconductor roller pulley 36 are gear-shaped, respectively. It was formed. The belts 39A and 39B that surround them are rack-shaped that engage with the gear-shaped parts on the peripheral surfaces of these pulleys 38A-1, 38A-2, 38B-2, 36, and are connected as a timing belt mechanism. There is.

【0032】

In the above configuration, when the shared motor 37 operates, the motor pulley 34 attached to the output shaft rotates integrally, and the first and second relay pulleys 38A and 38B rotate synchronously via the belt 39A. As a result, the development roller drive gear 33 is rotationally driven by the gear 38B-1 of the second relay pulley 38B, and the development roller 11 integrated with the development roller drive gear 33 rotates. Further, the first relay pulley 38A rotates the photoconductor roller drive pulley 36 via the belt 39B wound around the pulley 38A-2, and rotationally drives the photoconductor roller 7.

【0033】

As described above, according to the present embodiment, the photoconductor roller 7 and the developing roller 11 are combined with the first and second relay pulleys 38A and 38B and the belts 39A and 39B by using the shared motor 37 as a rotational drive source. Can be rotationally driven in synchronization. Therefore, as compared with the case where the intermediate gears are arranged as in the conventional case, the occurrence of rotational unevenness due to backlash can be prevented, the interference of the positional relationship between the members is reduced, and the size can be reduced.

【0034】

The mounting positions of the developing roller 11 and the photoconductor roller 7 may be reversed from those of the present embodiment. In this case, the developing rollers 11 are rotationally driven by the belts 39A and 39B.

【0035】

[Effect of the invention]

According to the present invention, the motor pulley fixed to the output shaft of the common motor is transmitted to the stepped pulley via the belt, and further transmitted to the photoconductor drive pulley via the stepped pulley, so that a single motor is used. The effective effect of being able to drive the device can be obtained, and the cost of the device can be reduced.

【0036】

Further, according to the present invention, the rotational force of the motor taken out from the motor pulley is transmitted to the first relay pulley by the first belt, and further transmitted to the drive pulley via the second belt to rotate the roller. The driving train and the rotational force of the motor taken out from the motor pulley are transmitted to the second relay pulley by the first belt, and the drive gear is transmitted through the gears arranged on the same rotation axis of the second relay pulley. Since it is composed of a drive row that rotates the rollers by transmitting to, it is possible to drive two rollers, a developing roller and a photoconductor roller, without using an intermediate gear just to fill the space. An effective effect can be obtained.

【0037】

As a result, it is possible to suppress the occurrence of uneven rotation and to save space, which is an effective effect.

【0038】

Further, since the motor pulley, the first relay pulley, and the second relay pulley are driven and transmitted via the first belt, the center position of each axis can be arbitrarily changed by changing the length of the belt. It also has the effect of facilitating specification changes and maintenance.

[Simple explanation of drawings]

[Figure 1]

Schematic diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2]

A perspective view showing a drive transmission mechanism between a photoconductor roller and a developing roller in the image forming apparatus of FIG. [Fig. 3]

Front view showing the drive transmission mechanism between the photoconductor roller and the developing roller in the image forming apparatus of FIG. [Fig. 4]

Perspective view showing the main part of the power transmission mechanism in the conventional photoconductor roller and the developing roller. [Fig. 5]

Front view showing the main parts of the power transmission mechanism in the conventional photoconductor roller and developing roller [Explanation of symbols]

1 Printer 2 supply cassette 3 Output paper 4 Paper feed roller 5 Transport roller 6 process unit 7 Photoreceptor roller (first roller) 8 Fixed shaft 9 Charger 10 Laser scanning unit 11 Develop roller (second roller) 12 Supply roller 13 Toner 14 Blade mounting plate 15 Develop blade 16 Transfer roller 17 Cleaning blade 18 Toner storage room 19 Agitator 20 Fixer 21 Heat roller 22 Pressurized roller 23 Paper ejection roller 24 Printed paper 25 Paper output tray 26 Display 30 plates 33 Develop roller drive gear 34 Motor pulley 36 Photoreceptor roller drive pulley 37 Shared motor 38A 1st relay pulley 38B 2nd relay pulley 39A belt 39B belt