JPH11202586A - Method for driving photoreceptor and transfer medium in image forming device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high image quality in multicolor or full color printing by toothing both surfaces of a timing belt linkedly arranged between driving sources. SOLUTION: Peak and trough parts are formed on both surfaces of the timing belt 47. When the double-toothed timing belt 47 is rotated through a motor pulley 44 by rotating a driving motor 11, a photoreceptor pulley 42 and the motor pulley 44 are rotated in the same direction because the pulleys 42 and 44 are meshed with the same surface of the belt 47. Meanwhile, an intermediate transfer body pulley 43 is meshed with a surface different from the pulley 44, so that it is rotated in a reverse direction to the pulleys 44 and 42. Then, a photoreceptor belt driving roller 2 coaxial with the pulley 42 and an intermediate transfer body belt driving roller 7 coaxial with the pulley 43 are rotated 10 the different directions. As a result, a photoreceptor belt 1 is rotated in a direction shown by an arrow A and an intermediate transfer body belt 6 is rotated in a direction shown by an arrow B differently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copying machine, a laser beam printer, and a facsimile, and more particularly to an image forming apparatus which develops an electrostatic latent image carried on a photoreceptor into a toner image. The present invention relates to a driving method capable of transferring a recording medium or an intermediate transfer member with high accuracy.

[0002]

2. Description of the Related Art As a color image forming apparatus, a plurality of developing units of different colors are sequentially developed on a photosensitive member, and a toner image on the photosensitive member is synthesized on an intermediate transfer member and then transferred collectively to paper. Is generally known. In addition, there is another type in which a plurality of developing units having different colors are sequentially developed on a photoconductor, and a toner image on the photoconductor is synthesized on a recording medium, that is, a recording sheet held on a rotating body. These color image forming apparatuses generally include a drive system that drives the photosensitive member and the intermediate transfer member to rotate from a power source such as a motor via a gear.

FIG. 3 is a structural view of a color image forming apparatus in which a photosensitive member and an intermediate transfer body are constituted by endless belts, and FIG. 4 is a structural view of a driving system of a conventional color image forming apparatus.

In FIG. 3, a photosensitive belt 1 is arranged in a closed loop inside the image forming apparatus. The photosensitive belt 1 is formed by applying a photosensitive receiving layer such as an organic photoconductor (OPC) in a thin film shape. A tension is applied to the support so that the vehicle can travel in the direction of arrow A. The photosensitive belt driving roller 2 includes:
As shown in FIG. 4B, the gear 5 is mounted coaxially.

An intermediate transfer belt 6 made of a conductive resin or the like is provided separately from the closed loop of the photosensitive belt 1 in FIG.
It is provided so that it can run in the direction of arrow B in the middle. The intermediate transfer member belt 6 is supported by an intermediate transfer member belt driving roller 7 and intermediate transfer member belt supporting / conveying rollers 8 and 9, and the driving roller 7 has a gear as shown in FIG. 10 are integrally provided.

A drive motor 11 for driving the photoreceptor belt 1 and the intermediate transfer member belt 6 is disposed at the shaft end of the drive rolls 2 and 7 for the photoreceptor and the intermediate transfer member as shown in FIG. I have. A small gear 12 attached to the output shaft of the drive motor 11 meshes with the gear 5, and the gear 5
The driving rollers 2 and 7 of the photoreceptor belt 1 and the intermediate transfer belt 6 are rotationally driven. That is, the photosensitive belt 1 is rotated by the drive motor 11 along the photosensitive belt driving roller 2 and the photosensitive belt supporting and conveying rollers 3 and 4 in the direction of arrow A. The intermediate transfer belt 6 is rotated by the drive motor 11 along the intermediate transfer belt driving roller 7 and the intermediate transfer belt support rollers 8 and 9 in the direction of arrow B.

The developer of each color of black (B), yellow (Y), magenta (M), and cyan (C) is stored at a position along the running surface of the photosensitive belt 1 and on the upper side of the path. Developing units 13B, 13Y, 13M, and 13C are provided. In addition, a photoconductor cleaning device 14, a static eliminator 15, and a charger 16 are disposed below the path of the photoconductor belt 1, respectively. Further, a laser beam generator 17 is provided above the photoreceptor belt supporting and conveying roller 4.
The laser beam generator 17 emits a laser beam 21 of image data.

The charger 16 includes a charging wire 18 made of a tungsten wire or the like, a shield plate 19 made of a metal plate, and a grid plate 20. And the charging wire 1
When a high voltage is applied to the photosensitive belt 1, the charged wire 18 causes a corona discharge and the photosensitive belt 1 via the grid plate 20.
Is uniformly charged.

In the case of a laser printer, the laser beam 21 is controlled by a signal from a host computer (not shown), and is applied to a specific component among a plurality of predetermined color components on the photosensitive belt 1 respectively. A corresponding plurality of electrostatic latent images are formed. Developing units 13B, 13Y, 13 for each color
M and 13C are detachably arranged in a vertical line at equal intervals in a vertical direction in a predetermined storage portion provided in the body of the body,
The inside of each developing unit has the same configuration except for the toner.

When developing an electrostatic latent image of a predetermined color, the developing devices 13B, 22Y, 22M and 22C respectively
B, 13Y, 13M, and 13C are contact cams for contacting the photosensitive belt 1. These contact cams 22B,
Reference numerals 22Y, 22M, and 22C are provided on a developing unit detachable cover 24 on the side of the apparatus main body. The developing unit detachable cover 24 is supported by a fixed developing unit detachable cover shaft 25 so as to be freely opened and closed. 23B, 23Y, 23M, and 23C are separation springs that separate the developing units 13B, 13Y, 13M, and 13C to the standby position.

An intermediate transfer roller 26 for transferring the toner image on the photosensitive belt 1 onto the intermediate transfer belt 6 is disposed at a position facing the photosensitive belt 1 with the intermediate transfer belt 6 interposed therebetween. I have. The surface circumference of the intermediate transfer belt 6 is set to be equal to the surface circumference of the photoreceptor belt 1. Reference numeral 27 denotes an intermediate transfer body belt cleaning device for scraping off residual toner on the intermediate transfer body belt 6, and is separated from the intermediate transfer body belt 6 while a synthetic image is formed on the intermediate transfer body belt 6. Contact only when used for cleaning.

On the lower side of the intermediate transfer belt 6, a sheet 2
9, a paper cassette 28 for storing the paper cassette 9 is provided. The paper 29 is transferred from the paper cassette 28 to the paper feed roller 30 and the separation unit 3.
1 feeds the paper one by one to the paper transport path 32. Further, in order to match the position of the sheet 29 with the composite image formed on the intermediate transfer belt 6, a registration roller 33 for temporarily stopping and waiting the sheet 29 and a driven roller 34 pressed against the registration roller 33 are respectively provided. Are located.

Reference numeral 35 denotes a paper transfer roller for transferring the composite image formed on the intermediate transfer belt 6 to the paper 29, and comes into contact with the intermediate transfer belt 6 only when the composite image is transferred to the paper 29. Rotate. Further, the fixing device 36 includes a heat roller 37 having a heat source therein and a pressure roller 38.
Is disposed on the exit side of the sheet 29, and the composite image transferred to the sheet 29 is fixed on the sheet 29 by pressure and heat with the nipping rotation of the heat roller 37 and the pressure roller 38 to form a color image. Reference numerals 39 and 40 denote a pair of paper discharge rollers provided downstream of the fixing device 36, and reference numeral 41 denotes a paper discharge tray provided on the upper portion of the machine body for storing the paper 29.

The operation of the conventional image forming apparatus configured as described above will be described below.

First, the drive motor 11 is rotated so that the gear 1
The photosensitive belt 1 is moved in the direction of arrow A, and the intermediate transfer belt 6 is moved in direction of arrow B by the photosensitive belt driving roller 2 and the intermediate transfer belt driving roller 7 which are connected by rows 2, 5, and 10.
To rotate in the direction.

Next, a high voltage is applied to the charging line 18 in the charger 16 connected to the high-voltage power supply to cause corona discharge to uniformly charge the surface of the photoreceptor belt 1 to about -500V to -650V. . When a laser beam 21 corresponding to a predetermined color of a plurality of color components, for example, a black (B) image is irradiated on the uniformly charged surface of the photoreceptor belt 1, the irradiation on the photoreceptor belt 1 is performed. The charge disappears in the portion where the electrostatic latent image is formed.

On the other hand, in the developing device 13B in which the black developer contributing to the development is stored, the contact cam 22B is rotated by a half turn in response to a color selection signal from a host computer (not shown). Abut. In the developing device 13B where the development is completed, the contact cam 22B is further rotated by half, and the developing device 13B is moved from the contact position with the photosensitive belt 1 to the standby position by the spring force of the separation spring 23B. While the developing device 13B is developing, the other developing devices 13Y, 13M, and 13C are separated from the photoconductor 1.

Next, when the color of, for example, cyan (C) is selected, the developing unit 13C is brought into contact with the photosensitive belt 1 to start the development of cyan. In the case of a copying machine or a printer using four colors, the developing operation is sequentially repeated four times to superimpose the four color toner images on the intermediate transfer belt 6 to form a composite image. The composite image thus formed is transferred to the paper transfer roller 3
5 is applied to the sheet 29 sent from the sheet cassette 28 along the sheet conveying path 32 by the pressure, and the fixing device 3
6, where it is fixed by the heat and the clamping force between the heat roller 37 and the pressure roller 38 to form a color image. The sheet 29 that has passed through the fixing device 36 is
The paper passes through 9, 40 and is discharged to the paper discharge tray 41.

[0019]

In recent years, in the field of image forming apparatuses, the need for higher image quality has been increasing year by year. This is due to the spread of CD-ROMs, etc., which has increased the opportunities for outputting photographic images than computers, and the fact that digital copiers configured by combining an image forming apparatus with an image reading apparatus have become popular. . High image quality in a color image includes high resolution, high color reproducibility, high gradation, and the like.

On the other hand, in the conventional image forming apparatus, as is apparent from FIG. 3, the photosensitive belt 1 and the intermediate transfer belt 6
Since the rotation directions are different from each other, it is necessary to change the rotation direction of one of the photoreceptor and the belts 1 and 6 of the intermediate transfer body by a gear or the like. That is, in the conventional example shown in the drawing, the photosensitive belt 1 is rotated in a direction different from that of the drive motor 11, and the intermediate transfer belt 6 is rotated in the same direction as the drive motor 11 by using gears.

However, gears are generally and widely used as mechanical drive transmission means as mechanical elements which are very excellent in terms of efficiency, design freedom and cost, but play (backlash) occurs between meshing gears. Is inevitable.

That is, for example, when a pair of gears such as spur gears are meshed and arranged, if they are mounted at the standard center distance, theoretically correct meshing rotation should occur. However, actually, in addition to the manufacturing tolerance of the gears, the deviation of the mesh due to the deformation of the tooth surface and the deflection of the shaft, etc., the teeth are squeezed due to the thermal expansion and contraction of the members supporting the gears and the gear train. Rotation may not be possible. For this reason, in order for the gears to transmit power smoothly, it is necessary to provide an appropriate amount of play between the tooth surfaces when the pair of gears mesh with each other, and this play is backlash.

In the case of a conventional image forming apparatus using the intermediate transfer belt 6 as shown in FIG.
Since the upper image is sequentially superimposed on the intermediate transfer belt 6, the photoreceptor belt 1 and the intermediate transfer belt 6 need to rotate accurately and in synchronization.

By rotating in synchronization with high precision in this manner, it is possible to form all colors without deviation.

However, in the conventional system, as shown in FIG. 4, the space between the photosensitive belt 1 and the intermediate transfer belt 6 is driven by the gears 5 and 10, so that the photosensitive body and the intermediate transfer body are respectively driven. There is a possibility that a phase shift corresponding to the backlash may occur between the belts 1 and 6, and a problem arises that a shift occurs between the colors due to the influence of the phase shift.

In a color image forming apparatus, superimposition of images of a plurality of colors with high accuracy is an important factor for achieving high image quality. The overlay accuracy of a color image is 100 μm for a general multi-color image, and at least 50 μm or less for a full-color image. For example, when forming a green line, yellow and cyan are superimposed,
In the case of a resolution of 600 DPI (dots / inch), which has become popular in recent years, the line width is 42 μm (1/600).
Inches), and if the line is shifted by 50 μm, the formed line becomes two lines of yellow and cyan, the color is changed, and the line becomes thicker, and the actual resolution is reduced.

The problem to be solved in the present invention is to realize high image quality of multi-color or full-color printing in an image forming method.

[0028]

SUMMARY OF THE INVENTION The present invention relates to an image forming apparatus for driving a photosensitive member, an intermediate transfer member, and a recording medium which are driven to rotate or travel in the respective rotational and traveling directions. This is basically based on a configuration in which belt driving is performed by a timing belt connected and arranged between the belts. In the case of reproducing a color image, the timing belt has teeth formed on both surfaces thereof, and even if there are a plurality of driven shafts on the driven side, all of these driving shafts are rotated in synchronization with each other. However, it is possible to form an image without color shift. That is, since there is no backlash caused by interposing the gears in the drive mechanism, it is possible to obtain an image in which the image quality does not deteriorate.

[0029]

According to the first aspect of the present invention, a photoreceptor capable of carrying an electrostatic latent image on its surface and the electrostatic latent image carried on the photoreceptor are sequentially developed with toners of different colors. An image having a plurality of developing units, superimposing a toner image developed on the surface of the photoreceptor on an intermediate transfer member, and transferring the toner image from the intermediate transfer member to a sheet to obtain a multi-color or full-color image In the forming apparatus, the photoconductor and the intermediate transfer body are converted into rotation or running motion through belt drive by a timing belt driven and driven by a drive system and having tooth profiles formed on both surfaces. Driving can be performed without a phase shift from the transfer member.

According to a second aspect of the present invention, there is provided a photosensitive member capable of carrying an electrostatic latent image on a surface thereof, and a plurality of developing members for sequentially developing the electrostatic latent image carried on the photosensitive member with a plurality of toners of different colors. A toner image developed on the surface of the photoreceptor is superimposed on an intermediate transfer body, the toner composite image is transferred from the intermediate transfer body to paper to form a multi-color or full-color image, and In an image forming apparatus for driving the photosensitive member and the intermediate transfer member by a single drive source, a belt formed by a timing belt having the photosensitive member and the intermediate transfer member traveled and driven by a drive system and having tooth profiles formed on both surfaces. This is converted into rotation or running motion through driving, and can be driven without a phase shift between the photosensitive member and the intermediate transfer member.

According to a third aspect of the present invention, there is provided a photoreceptor capable of forming an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photoreceptor with a plurality of toners of different colors. An image forming apparatus for forming a color toner image by sequentially superimposing and transferring a plurality of color toner images developed on the surface of the photoreceptor onto a recording medium held on a rotating body. The body and the rotating body are converted into rotation or running motion through belt drive by a timing belt driven and driven by a drive system and having tooth profiles formed on both surfaces, and the phase shift between the photosensitive body and the intermediate transfer body is performed. Can be driven without the occurrence of.

According to a fourth aspect of the present invention, there is provided a photoreceptor capable of forming an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photoreceptor with a plurality of toners of different colors. A multi-color toner image developed on the surface of the photoreceptor is sequentially superimposed and transferred to a recording medium held on a rotating body to form a color toner image, and the photoreceptor and the In an image forming apparatus in which a rotating body is driven by a single drive source, the photosensitive member and the rotating body are driven to rotate by a drive system and rotated or moved by a belt driven by a timing belt having teeth formed on both surfaces. , And can be driven without a phase shift between the photoconductor and the rotating body.

According to a fifth aspect of the present invention, there is provided a photosensitive member capable of carrying an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photosensitive member with toners of different colors. And an image forming apparatus for transferring a toner image developed on the surface of the photosensitive member to an intermediate transfer member, and further transferring the toner image from the intermediate transfer member to a recording medium. This is a device, and a reproduced image without color shift can be obtained even for a color image.

According to a sixth aspect of the present invention, there is provided a photosensitive member capable of carrying an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photosensitive member with toners of different colors. 5. An image forming apparatus for directly transferring a toner image developed on a surface of the photoconductor to a recording medium, comprising: a driving method according to claim 3; Since no deviation occurs,
A color image forming apparatus capable of high color matching accuracy can be realized.

According to a seventh aspect of the present invention, the photoreceptor and the intermediate transfer member are provided with rotary drive shafts for driving the respective photoreceptors and the intermediate transfer member. 6. The image forming apparatus according to claim 5, further comprising a pulley formed on said photosensitive drum and a timing belt, wherein said pulley and said timing belt are wound so as to drive said photosensitive member and said intermediate transfer member in respective rotational directions. Since the phase shift of the intermediate transfer member does not occur, a color image forming apparatus capable of high color matching accuracy can be realized.

According to the present invention, the photoreceptor and the rotator are provided with a rotary drive shaft for driving each of them.
These rotary drive shafts are provided with pulleys formed on the outer periphery with tooth surfaces matching the tooth shape of the timing belt, and the respective pulleys and the timing belt are wound so as to drive the photoconductor and the rotary body in the respective rotation directions. The image forming apparatus according to claim 6, wherein a phase shift between the photoconductor and the rotating body does not occur, so that a color image forming apparatus capable of high color matching accuracy can be realized.

Hereinafter, embodiments of the present invention will be described. In the present invention, the photosensitive belt drive roller 2 and the intermediate transfer body belt drive roller 7 described with reference to FIGS.
A belt drive is applied to the rotary drive of FIG. 5, and a part of a general timing belt is shown in a perspective view in FIG. 5 in order to make the present invention easier to understand.

The timing belt 51 shown in FIG. 5 has uniform peaks 51a and valleys 51 at a constant pitch on one side of its surface.
b is formed. The timing belt 51 having such a shape has various features such as lubrication, synchronous transmission, light weight, and quiet operation, as is well known in the art. The pulley around which the timing belt 51 is wound has a profile matching the peaks 51a and the valleys 51b, so that the peaks 51a and the valleys 51b of the timing belt 51 are aligned with the pulleys and meshed without gaps. be able to. Thereby, the plurality of mountains 51a
Since the valleys 51b mesh with the valleys and the valleys on the pulley side, the backlash is substantially zero, and high rotational accuracy and backlashless driving (no backlash) can be realized.

FIG. 2 is a schematic perspective view showing a part of the timing belt 47 used in the present invention.

As is clear from the figure, the timing belt 47 has peaks 47a and valleys 47b and peaks 4
7c and a valley 47d are formed.
a, 47c and valleys 47b, 47d have the same shape. Thus, the peaks 47a are formed on both sides of the timing belt 47.
And the valley 47b and the valley 47c and the valley 47d, when the timing belt 47 forms a closed loop, one ridge 47a and the valley 47b mesh with the pulley outside the loop, and the other ridge 47c and the valley 47d It can be engaged with a pulley located inside the loop. As in the case of the general timing belt 51 shown in FIG. 5, peaks 47a, 47c and valleys 47b, 4
Even if 7d is formed, rotation can be transmitted to the pulley without backlash.

FIG. 1 shows a driving configuration of an image forming apparatus using a driving method according to an embodiment of the present invention.
The structure of the image forming apparatus is the same as that shown in FIG. 3 except for the drive unit, and the same members are designated by the same reference numerals, and detailed description thereof will be omitted.

A photoreceptor pulley 42 is coaxially mounted on the photoreceptor belt drive roller 2, and an intermediate transfer member pulley 43 is coaxially mounted on the intermediate transfer belt drive roller 7.
And an output shaft of the drive motor 11 is provided with a motor pulley 44. And these pulleys 42 ~
In addition to 44, an idler pulley 45 and a tension pulley 46 are respectively arranged at predetermined positions.
In order to apply an appropriate tension to the timing belt 47, a bracket 48 elastically supported by a coil spring 49 is provided, and the tension pulley 46 is rotatably held by the bracket 48.

The timing belt 47 shown in FIG. 2 is wound around each of the pulleys 42 to 46 in a closed loop. At this time,
A timing belt 47 is provided on the outer peripheral surface of each of the pulleys 42 to 46.
Of the peaks 47a, 47c and the valleys 47b, 47d. The rotation of the output shaft of the drive motor 11 is transmitted from the motor pulley 44 to the photoreceptor pulley 42 and the intermediate transfer pulley 43.

The operation of the embodiment of the image forming apparatus according to the present invention configured as described above will be described below.

In FIG. 1, first, the drive motor 11 is rotated, and the timing belt 47 of both teeth is rotated via the motor pulley 44. As is apparent from the figure, since the photoreceptor pulley 42 and the motor pulley 44 mesh with the same surface of the timing belt 47, these pulleys 4
2, 44 rotate in the same direction. On the other hand, since the intermediate transfer member pulley 43 is engaged with a different surface from the motor pulley 44, the motor pulley 44 and the photosensitive pulley 4
2. Rotate in the opposite direction. Since the photoreceptor pulley 42 is provided coaxially with the photoreceptor belt driving roller 2 and the intermediate transfer member pulley 43 is provided coaxially with the intermediate transfer member belt driving roller 7, the photoreceptor belt driving roller 2 and the intermediate transfer The body belt driving roller 7 rotates in a different direction, and as a result, the photosensitive belt 1
Rotates in different directions in the direction of arrow B.

Next, a high voltage is applied to the charging line 18 in the charger 16 connected to the high-voltage power supply to cause corona discharge to uniformly charge the surface of the photoreceptor belt 1 to about -500 V to -650 V. When a laser beam 21 corresponding to an image of a predetermined color in a plurality of color components, for example, a black (B) image, is irradiated on the surface of the photosensitive belt 1 uniformly charged,
The irradiated portion on the photoreceptor belt 1 loses the charge, and an electrostatic latent image is formed. On the other hand, the developing device 13B in which the black developer contributing to the development is stored is contacted with a contact cam 22B by a color selection signal from a host computer (not shown).
Makes a half turn, and thereby comes into contact with the photoreceptor belt 1. In the developing device 13B where the development is completed, the contact cam 22B is further rotated by a half turn, and is moved from the contact position with the photosensitive belt 1 to the standby position by the spring force of the separation spring 23B. Developing unit 13B
During the development, the other developing units 13Y, 13M, 13C
Is separated from the photoconductor 1. Next, for example, cyan (C)
Is selected, the developing unit 13C is brought into contact with the photoreceptor belt 1 to start developing cyan. In the case of a copier or printer using four colors, the developing operation is sequentially repeated four times, and the four color B, C, M, and Y toner images are superimposed on the intermediate transfer belt 6 to form a composite image. The composite image formed in this manner is applied to the paper transfer roller 35 with a high voltage having a polarity opposite to that of the toner, and the pressure is applied to the paper cassette 2.
8 is transferred collectively to the sheet 29 sent along the sheet transport path 32 and then sent to a fixing device 36, where the color image is fixed by heat and the clamping force of the heat roller 37 and the pressure roller 38. It is formed. The sheet 29 that has passed through the fixing device 36 passes through a pair of discharge rollers 39 and 40 and is discharged to a discharge tray 41.

In the transfer process on the paper 29 as described above, the rotation from the drive motor 11 drives the photosensitive belt 1 and the intermediate transfer belt 6 to travel via the timing belt 47 instead of the gear train. For this reason, as described with reference to FIG. 1, since the photosensitive belt 1 and the intermediate transfer belt 6 are run in synchronization with high accuracy, the toner image formed on the photosensitive belt 1 is accompanied by a phase shift. The image can be transferred to the intermediate transfer belt 6 without any need. Therefore, in the reproduction of a color image, it is possible to obtain a clear and high-quality image without causing a positional shift of each color toner.

That is, as described in the conventional example, in the image forming apparatus, how to superimpose images of each color with high accuracy is a major factor in pursuing high image quality. The intermediate belt 6 and the intermediate transfer belt 6 can be driven by the timing belt 47 without backlash, so that there is no rotational displacement between them and high color overlay accuracy can be realized.

Further, since the photoreceptor belt 1 is driven by the timing belt 47, the speed fluctuation due to the driving is small. According to the experimental results of the inventor, the rotational speed unevenness on the driven side in the drive by the timing belt 47 was about よ り of that in the drive by the general helical gear. And
Timing belt 4 with low processing cost for transmitting driving force
7, the cost can be reduced. Further, since the irradiation position of the laser beam is set in the vicinity of the photosensitive belt driving roller 2 or on the contact surface between the photosensitive belt driving roller 2 and the photosensitive belt 1, the laser beam is affected by the extension and vibration of the photosensitive belt 1. Hateful. From these facts, it becomes possible to drive the photoreceptor belt 1 with less speed fluctuation.

[0050]

According to the present invention, when an electrostatic latent image formed on a photoreceptor such as a photoreceptor belt is developed and transferred to a transfer target, the drive between the photoreceptor and the transfer target is performed by the timing belt. By using the belt drive, synchronization can be performed with high accuracy. For example, a clear and high-quality image can be formed even with a color image without color shift or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a driving configuration of an image forming apparatus using a driving method according to an embodiment of the present invention;

FIG. 2 is a schematic perspective view showing a part of a timing belt used in the present invention.

FIG. 3 is a structural diagram of a color image forming apparatus in which a photosensitive member and an intermediate transfer member are constituted by endless belts.

FIG. 4 is a configuration diagram of a driving system of a conventional color image forming apparatus.

FIG. 5 is a perspective view of a part of a general timing belt.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoreceptor belt 2 photoreceptor belt drive roller 3, 4 photoreceptor belt support transport roller 5 gear 6 intermediate transfer belt 7 intermediate transfer belt drive roller 8, 9 intermediate transfer belt support transport roller 10 gear 11 drive motor 12 small Gear 13B Developing device (black) 13Y Developing device (yellow) 13M Developing device (magenta) 13C Developing device (cyan) 14 Photoconductor cleaning device 15 Static eliminator 16 Charger 17 Laser beam generator 18 Charging line 19 Shield plate 20 Grid plate Reference Signs List 21 laser beam 22B contact cam (B) 22Y contact cam (Y) 22M contact cam (M) 22C contact cam (C) 23B separation spring (B) 23Y separation spring (Y) 23M separation spring (M) 23C Separating spring (C) 24 Developing unit removable cover 25 Developing unit removable cover shaft 26 Intermediate transfer row 27 Intermediate Transfer Body Belt Cleaning Device 28 Paper Cassette 29 Paper 30 Paper Feed Roller 31 Separation Unit 32 Paper Transport Path 33 Registration Roller 34 Follower Roller 35 Paper Transfer Roller 36 Fixing Unit 37 Heat Roller 38 Pressure Roller 39 Discharge Roller 40 Discharge Roller 41 Discharge tray 42 Photoconductor pulley 43 Intermediate transfer body pulley 44 Motor pulley 45 Idler pulley 46 Tension pulley 47 Timing belt 48 Bracket 49 Elastic member

Claims (8)

[Claims] A photosensitive member capable of carrying an electrostatic latent image on a surface thereof; and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photosensitive member with toners of different colors. In an image forming apparatus for superimposing a toner image developed on the surface of a body on an intermediate transfer member and transferring the toner image from the intermediate transfer member to a sheet to obtain a multi-color or full-color image, the photosensitive member and the intermediate transfer member A method for driving a photoconductor and a transfer medium in an image forming apparatus, wherein the body is converted into rotation or running motion through belt driving by a timing belt driven and driven by a drive system and having teeth formed on both surfaces. A photosensitive member capable of carrying an electrostatic latent image on a surface thereof; and a plurality of developing devices for sequentially developing the electrostatic latent image carried by the photosensitive member with a plurality of toners of different colors. The toner image developed on the surface of the photoreceptor is superimposed on an intermediate transfer member, and the toner composite image is transferred from the intermediate transfer member to a sheet to form a multi-color or full-color image. In an image forming apparatus in which a transfer body is driven by a single drive source, the photosensitive body and the intermediate transfer body are driven to run by a drive system and rotated or run through a belt drive by a timing belt having teeth formed on both sides. A method for driving a photosensitive member and a transfer medium in an image forming apparatus, wherein the method converts the movement into motion. 3. A photoreceptor capable of forming an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photoreceptor with a plurality of toners of different colors, In an image forming apparatus that sequentially superimposes and transfers a plurality of color toner images developed on the surface of a photoconductor onto a recording medium held on a rotator to form a color toner image, the photoconductor and the rotator are A method of driving a photosensitive member and a transfer medium in an image forming apparatus, wherein the driving force is converted into rotation or running motion through belt driving by a timing belt driven and driven by a drive system and having tooth profiles formed on both surfaces. 4. A photoreceptor capable of forming an electrostatic latent image on a surface thereof, and a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photoreceptor with a plurality of toners of different colors, A plurality of color toner images developed on the surface of the photoreceptor are successively superimposed and transferred onto a recording medium held on a rotating body to form a color toner image, and the photoreceptor and the rotating body are formed into a single unit. In an image forming apparatus driven by a driving source, the photoconductor and the rotating body are converted into rotation or running motion through belt driving by a timing belt driven and driven by a driving system and having teeth formed on both surfaces. For driving a photoconductor and a transfer medium in an image forming apparatus. 5. A photosensitive member capable of carrying an electrostatic latent image on a surface thereof, a plurality of developing devices for sequentially developing the electrostatic latent image carried by the photosensitive member with toners of different colors, and Transfer the toner image developed on the surface to the intermediate transfer body,
An image forming apparatus for transferring the image from the intermediate transfer member to a recording medium, the image forming apparatus including the driving method according to claim 1. 6. A photosensitive member capable of carrying an electrostatic latent image on its surface, a plurality of developing devices for sequentially developing the electrostatic latent image carried on the photosensitive member with toners of different colors, and An image forming apparatus for directly transferring a toner image developed on a surface to a recording medium, comprising the driving method according to claim 3 or 4. 7. A photoreceptor and an intermediate transfer member are provided with rotary drive shafts for driving the respective photoreceptors, and a pulley having a tooth surface formed on the outer circumference of the rotary drive shaft to match the tooth profile of the timing belt, 6. The image forming apparatus according to claim 5, wherein each pulley and the timing belt are wound so as to drive the photoconductor and the intermediate transfer body in respective rotation directions. 8. The photoreceptor and the rotator are provided with rotary drive shafts for driving the respective photoreceptors, and the rotary drive shafts are provided with pulleys formed on the outer periphery with tooth surfaces matching the tooth profile of the timing belt. 7. The image forming apparatus according to claim 6, wherein the pulley and the timing belt are wound so as to drive the photosensitive member and the rotating member in respective rotating directions.