JP2000330358A - Color electrtophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-quality color image without causing positional deviation at the time of superimposing colors by allowing a photoreceptor belt to come in contact with an intermediate transfer body belt by specified pressing force and allowing the intermediate transfer body belt to be rotated by following the driving of the photoreceptor belt. SOLUTION: The photoreceptor belt 2 is horizontally stretched and laid by a driving roller 22 driven by a driving means and a driven roller 21 functioning also as a tension roller giving tension to the belt 2, and is rotated in a direction shown by an arrow at constant speed. The intermediate transfer body belt 3 coming in contact with the belt 2 is stretched and laid vertically to the horizontal surface of the belt 2 by a driven roller 31 and a driven roller 32 functioning also as a tension roller giving the tension to the belt 3. The belt 3 is arranged so that its one part may come in contact with the belt 2 at the position (contact part 7) of the belt 2 opposed to the roller 22, and rotated by following the driving of the belt 2.

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 electrophotographic apparatus for recording a color image, and more particularly to a color electrophotographic apparatus utilizing an electrophotographic process.

[0002]

2. Description of the Related Art There are many known methods for recording a color image in accordance with image information from a computer or the like.
Among these, a method using electrophotography is effective as a method capable of recording a high-quality color image at a relatively high speed. In color image recording using electrophotography, yellow, magenta, cyan, and black toner images are formed on a recording material that is a photoreceptor, and the formed toner images are printed on paper or an intermediate transfer member. The color image is formed by superimposing and synthesizing.

However, an electrophotographic color image forming apparatus requires a plurality of developing machines or an intermediate transfer member around a photosensitive drum in order to develop a plurality of color toners. In addition, the handling properties of the developing machine and the like are deteriorated. In addition, there is a drawback that the entire apparatus becomes large and the handling of the apparatus is poor.

In a color image forming apparatus, it is important to superpose toner images of each color on paper or on an intermediate transfer member for high image quality. For this reason, it is also necessary to drive the photoconductor, paper, or intermediate transfer member with high accuracy at the same time as the size of the apparatus is reduced.

[0005] As a conventional device for solving these problems,
Although there is a drum-shaped intermediate transfer member, there is a problem that the occupation ratio of the intermediate transfer member in the apparatus is high and it is difficult to reduce the size.

Japanese Patent Application Laid-Open No. Hei 9-211926 discloses a known technique in which an intermediate transfer member is formed into a belt shape from a drum shape. This known technique discloses an apparatus in which four developing machines are arranged on a photoreceptor belt having a horizontal surface, and an image is transferred by being superimposed on an intermediate transfer belt.

However, since each of the photoreceptor belt and the intermediate transfer belt which are stretched over the two rollers is driven via a separate drive source or a gear or the like, a mechanical dimensional error of each roller is required. It is difficult to drive with high accuracy due to the above factors. In addition, there is a disadvantage that the alignment accuracy of each color toner image is reduced. Further, since the photoreceptor belt and the intermediate transfer member belt are arranged in a triangular manner, the size of the apparatus has been increased.

Further, Japanese Patent Application Laid-Open Nos. 5-53406 and 7-1
In Japanese Patent No. 04546, the photoconductor belt is stretched in the horizontal direction, the intermediate transfer belt is stretched in the vertical direction with respect to the photoconductor belt,
An example in which a plurality of developing devices are arranged on the upper surface of the photoreceptor belt to reduce the size is shown.

[0009]

However, these prior arts do not consider a driving method. When an intermediate transfer member using a film-shaped belt is stretched in the vertical direction and driven directly by a driving unit, the belt is conveyed against gravity, and unstable behavior such as vibration is likely to occur. . Then, the winding angle between the drive roller of the intermediate transfer belt and the intermediate transfer belt changes slightly, and the conveyance force from the drive roller also becomes unstable. Then, this becomes a factor for slightly changing the transport speed of the film-like intermediate transfer body.

In view of the above circumstances, the present invention provides a color electrophotographic apparatus using a belt-shaped photoreceptor and a belt-shaped intermediate transfer member, and can obtain a high-quality color image without any displacement during color superposition. An object is to provide a color electrophotographic apparatus.

[0011]

In order to achieve the above object, at least a photosensitive belt and an intermediate transfer belt are provided.
The intermediate transfer belt is stretched by two rollers, and the intermediate transfer belt is stretched in the vertical direction by at least two rollers, and comes into contact with the photosensitive belt on the surface stretched in the vertical direction. The photoreceptor belt supports a driving roller for driving the photoreceptor belt such that the photoreceptor belt can contact the intermediate transfer member belt with a predetermined pressing force.
The intermediate transfer belt was rotated by receiving a driving force from the photosensitive belt.

In the above configuration, since the intermediate transfer member belt rotates by obtaining a driving force from a contact portion with the photosensitive member belt,
Even when placed vertically, the intermediate transfer belt can always rotate at the same speed as the photoreceptor belt with high accuracy.
The alignment of each color toner image can be reliably realized, and a high quality image can be obtained.

Further, in the above construction, the supporting member for supporting the shaft of the roller for driving the photosensitive belt is provided with a shaft of the driving roller so that the photosensitive belt can contact the intermediate transfer belt with a predetermined pressing force. To support. In the present invention,
By positioning the photoreceptor belt at an appropriate position by the support member, a predetermined pressing force is obtained, and the intermediate transfer member belt can always rotate with high precision with respect to the photoreceptor belt.

In the present invention, the photoreceptor belt and the intermediate transfer belt are in contact with a predetermined pressing force, and the pressing force between the photoreceptor belt and the intermediate transfer belt is twice or more the dynamic friction force. It is desirable to be configured as follows.

Further, it is easy to secure the pressing force by coating a rubber-based material for increasing the frictional force on both ends in the width direction in the non-image forming area of the photosensitive belt or the intermediate transfer belt. become.

Further, a sensor for detecting the rotational speed of the intermediate transfer belt is provided, and the photosensitive belt is driven and controlled based on the output of the sensor so that the intermediate transfer belt rotates at a predetermined cycle, thereby further increasing the speed. The intermediate transfer member belt and the photosensitive member belt can be rotationally driven with high precision.

Further, the photoreceptor belt is stretched in a horizontal direction, a plurality of developing machines and exposure devices are arranged above a horizontal plane of the photoreceptor belt, and a paper cassette is arranged below the photoreceptor belt. Since the fixing device is arranged on the opposite side of the photoreceptor belt across the bridged intermediate transfer member belt, the overall size of the apparatus can be reduced.

Further, since the photoreceptor belt and the paper cassette can be attached and detached in the horizontal direction, and the developing device and the fixing device can be attached and detached in the vertical direction, a compact color electrophotographic apparatus can be realized with high maintainability.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view for explaining the schematic arrangement of a color laser printer which is a color electrophotographic apparatus to which the present invention is applied.

A photosensitive belt 2 provided in the color laser printer 1 shown in FIG. 1 has a driving roller 22 driven by driving means (not shown) and a driven roller which also serves as a tension roller for applying tension to the photosensitive belt 2. It is stretched horizontally by 21 and rotates at a constant speed in the direction of the arrow.

The intermediate transfer belt 3 in contact with the photoreceptor belt 2 is perpendicular to the horizontal plane of the photoreceptor belt 2 by a driven roller 31 and a driven roller 32 which also serves as a tension roller for applying tension to the intermediate transfer belt 3. It is stretched over. A part of the intermediate transfer belt 3 is arranged so as to be in contact with the photoreceptor belt 2 at a position opposing the driven roller 22 of the photoreceptor belt 2 (contact portion 7).

The charger 4 uniformly charges the surface of the photosensitive belt 2. The exposure device 5 exposes the surface of the photoreceptor belt 2 uniformly charged by the charger 4 with a laser to form an electrostatic latent image on the surface of the photoreceptor belt 2.

The developing device 6 is arranged on a horizontal plane above the photoreceptor belt 2, and develops the electrostatic latent image to form a toner image. In this embodiment, the developing device 61 uses a yellow toner, the developing device 62 uses a magenta toner, the developing device 63 uses a cyan toner, and the developing device 64. Is a developing device using black toner. The developing function is given or eliminated by controlling the bias voltage in each developing device.

The blade 8 removes toner remaining on the surface of the photosensitive belt 2. The removed toner is mainly the toner remaining after the toner image formed on the photosensitive belt 2 is transferred to the intermediate transfer belt 3.

The erase lamp 9 removes the charge remaining on the surface of the photoreceptor belt 2 after transferring the toner image.

A transfer material such as a sheet stored in the cassette 10 is fed by a feed roller 11. Paper feed roller 11
The transfer material such as the paper fed by the registration roller 1
The toner image formed on the intermediate transfer belt 3 is transferred by the transfer roller 13 by correcting the conveyance posture by the transfer roller 13.

The transfer material onto which the toner image has been transferred is supplied to a fixing device 14.
As a result, the toner image is welded (fixed). After the toner image is fixed, the transfer material such as the sheet discharged outside the machine is transferred to a sheet discharging unit 1.
7 is stored. The cleaner 15 is used for the intermediate transfer belt 3.
The toner remaining on the surface is removed.

Next, a method of forming a color image by the present apparatus will be described. When a print signal is sent from an information processing device (not shown) to the printer 1 in a print standby state after the power is supplied to the printer 1, the printer 1 forms a toner image corresponding to each toner color from the print signal. Prepare to do. The exposing device 5 irradiates a laser beam corresponding to each color toner image onto the photosensitive belt 2 uniformly charged by the charger 4. On the photoreceptor belt 2, an electrostatic latent image corresponding to the color of the toner to be developed is formed.

First, an electrostatic latent image corresponding to a yellow toner image is formed on the photoreceptor belt 2 by the exposure device 5, and is developed by the yellow developing device 61 to form a toner image. The toner image formed on the photoreceptor belt 2 is transferred to the surface of the intermediate transfer belt 3 by contacting the contact portion 7 with the intermediate transfer belt 3 and is held on the surface of the intermediate transfer belt 3. When the toner image is transferred to the intermediate transfer belt 3, the toner image is transferred from the photosensitive belt 2 to the intermediate transfer belt 3.
A bias voltage for transfer to the recording medium is applied by a transfer voltage applying unit (not shown). This bias voltage is controlled so as to be able to be appropriately changed according to the lamination state of the superposed toner images.

On the other hand, after the toner remaining on the photosensitive belt 2 after the transfer of the toner image is removed by the blade 8 without being transferred, the charge remaining on the surface of the photosensitive belt 2 is removed by an erase lamp 9. It has become.

After the step of returning the surface of the photosensitive belt 2 to the initial state is completed, a magenta toner image of the next color is formed on the surface of the photosensitive belt 2 in the same manner as the yellow toner image. The image is transferred onto the surface of the intermediate transfer belt 3. The yellow toner image held on the surface of the intermediate transfer belt 3 is superimposed on the magenta toner image and held on the intermediate transfer belt 3.

The same process is repeated for the cyan and black colors, so that the four color toner images are superimposed on the intermediate transfer belt 3 and simultaneously held on the surface of the intermediate transfer belt 3.

The four color toner images formed on the surface of the intermediate transfer belt 3 in this manner are transferred onto the paper 16.
The rotation driven paper feed roller 11 separates the paper 16 stored in the cassette 10 one by one, and
The paper 16 is transported up to that point. After correcting the skew of the sheet 16 by the registration roller 12, the sheet feeding roller 11 stops. The registration roller 12 starts the rotation of the registration roller 12 at a timing matching with the toner image on the intermediate transfer belt 3. At the timing when the leading end of the conveyed paper 16 comes into contact with the intermediate transfer belt 3, the transfer roller 13 is pressed from the back of the paper 16, and the toner image on the surface of the intermediate transfer belt 3 is transcribed on the paper 16. Electrotransfer.
To perform electrostatic transfer, an appropriate bias voltage is applied to the transfer roller 13.

As described above, the toner image provided on the intermediate transfer belt 3 is transferred, and the paper 16 on which the toner image has been transferred passes between the heating roller and the pressure roller of the fixing device 14, and An image instructed to be printed is fixed on 16. The paper 16 on which the image has been fixed is discharged to the paper discharge unit 17 on the upper part of the printer 1 to stop the printing operation, and the printer 1 is again in the print standby state.

In FIG. 1, the number of rollers for bridging the photoreceptor belt 2 and the intermediate transfer belt 3 is two, so that the driven roller 21 for the photoreceptor belt and the driven roller 32 for the intermediate transfer belt are tensioned to the belt. Also serves as a tension roller. As shown in FIG. 2, instead of the driven rollers 21 and 32, a tension roller 24 is separately provided on the photoreceptor belt 2 and a tension roller 34 is provided on the intermediate transfer belt 3 to distribute functions given to the driven rollers 21 and 32. You may.

Next, a description will be given of a method of aligning the overlapping positions of the toner images of the respective colors according to the present invention. In a color printer, the registration accuracy of each color toner image is one of the important factors that determine the image quality. If the overlapping position of each color is shifted, the hue changes or the color becomes uneven, thereby deteriorating the image quality. In the method using the photoreceptor and the intermediate transfer member, the overlapping position of each color is realized by synchronizing the speeds of both with high accuracy or driving each of them at a predetermined speed with high accuracy. For this reason, it is a commonly used means to provide a drive source such as a motor for each of the photoreceptor and the intermediate transfer body, or to connect and drive both using a gear or the like.

However, it has been extremely difficult to stably realize a predetermined speed due to the mechanical dimensional accuracy of the photosensitive member and the intermediate transfer member, dimensional change due to the environment, and the like. Also,
At the contact portion between the photosensitive member and the intermediate transfer member, an electric field is formed between the photosensitive member belt 2 and the intermediate transfer member belt 3 by the mechanical frictional force and the bias voltage applied to the intermediate transfer member belt 3 so that the electric field is generated between the two members. Therefore, even if there is a slight speed difference, a shear force acts on a contact portion between the two, and each speed fluctuates minutely, causing a color overlay position shift. In particular, when a belt is used for both belts, each belt speed is determined by a change in the outer dimensional accuracy of the roller that drives the belt, a change in the coefficient of friction between the belt and the drive roller, a change in the belt winding angle around the drive roller due to belt vibration, and the like. Is very difficult to drive at a predetermined value.

Further, when the film-shaped belt is driven over the vertical direction, the belt must be conveyed against gravity, so that a small vibration mode appears on the belt, and the driving roller is driven at a predetermined speed. However, there has also been a problem that the winding angle of the belt around the drive roller is slightly changed, and the speed of the belt deviates from a predetermined value.

When an attempt is made to reduce the size of the apparatus by using the photoreceptor belt 2 and the intermediate transfer belt 3 as shown in FIG. 1, one of the belts has to be stretched in the vertical direction, so that the above problem is encountered. .

Therefore, in the present invention, a drive source (not shown) is provided on the photosensitive belt 2 side in which the belts are arranged in a horizontal direction, and the drive belt 22 is driven to drive the photosensitive belt 2, and the intermediate transfer belt is driven. 3 is a photoreceptor belt 2
It is configured to be driven by the frictional force generated at the contact portion 7 with the electric power and the electric attraction force. Thus, even when the intermediate transfer belt is arranged so as to extend in the vertical direction, the conveyance speed of the intermediate transfer belt 3 is stabilized according to the speed of the photosensitive belt, and synchronization with the photosensitive belt 2 is ensured. Will be able to do it. Therefore, the registration accuracy of each color is improved, and high image quality can be achieved.

When the intermediate transfer belt 3 is driven by the photoreceptor belt 2, the color registration is performed in such a manner that the photoreceptor belt 2 and the intermediate transfer belt 3 rotate at the same speed, and the outer peripheral length of the intermediate transfer belt 3. Is a length that can print one page of paper, and is achieved by forming a toner image of each color on the photosensitive belt 2 every rotation cycle of the intermediate transfer belt 3.
Therefore, it is important that the intermediate transfer belt 3 be rotated at a predetermined speed.

When the main body of the printer 1 is activated by turning on the power, the photosensitive belt 2 is rotated by a driving force applied from a drive source (not shown) to the drive roller 22, and the intermediate transfer belt 3 is brought into contact with the photosensitive belt 2. The driving force is transmitted from the frictional force of the contact and the electrostatic attraction force from the contact member 7 to rotate. At this time,
A sensor (not shown) is provided on the intermediate transfer belt 3 to detect the rotation speed of the intermediate transfer belt 3 and to determine the speed of a drive source for driving the photosensitive belt 2 so that the intermediate transfer belt rotates at a predetermined cycle. adjust.

Since the speed of the intermediate transfer belt 3 varies due to the dimensional error of the drive roller 22 of the photosensitive belt 2, environmental change, temperature rise in the printer body 1, etc., the intermediate transfer belt 3 moves at a predetermined speed. The speed of the intermediate transfer belt 3 is corrected when the power of the printer body is turned on, when printing is started, and during printing. As a result, a good image without color misregistration can be obtained.

Here, in order for the photoreceptor belt 3 to reliably convey the intermediate transfer belt 3 at a predetermined speed, the driving force at the contact portion 7 between the two acts on the intermediate transfer belt 3.
For example, the bearing sliding portions of the rollers 31 and 32, the cleaner 1
5. It must be sufficiently large with respect to the load received from the transfer roller 11. FIG. 3 shows the relationship between the driving force of the intermediate transfer member belt 3 generated at the contact portion 7 of the photosensitive member belt 2 and the load acting on the intermediate transfer member belt with respect to the pressing force of the drive roller 22 against the intermediate transfer member belt 3. FIG. 7 is a diagram showing a result obtained by experiment. In FIG. 3, the pressing force of the photosensitive belt is set to 1 when the driving force and the load of the intermediate transfer belt are equal, that is, when the photosensitive belt cannot drive the intermediate transfer belt. That is, the pressing force of the photosensitive belt is a dynamic friction force between the photosensitive belt 2 and the intermediate transfer belt 3. In FIG. 3, the black circles indicate the case where the photosensitive belt 2 is pressed against the roller 31 of the intermediate transfer belt 3 (the state shown in FIG. 4).

In the state shown in FIG. 4, even if the photosensitive belt 2 is slightly pushed into the intermediate transfer belt 3, a large pressing force acts, and the photosensitive belt 2 and the rollers 31 hold the intermediate transfer belt 3 therebetween. Since the intermediate transfer belt 3 is driven, a large transport force is generated on the intermediate transfer belt 3 linearly against the load.

On the other hand, in FIG.
Is pressed against the surface of the intermediate transfer belt 3 where the roller 31 does not face (the state shown in FIG. 5).

In the state shown in FIG. 5, the photosensitive belt 2 receives a reaction force from the intermediate transfer belt 3 to obtain a mechanical frictional force. While the driving force of the belt 3 is increased, the bearing load of the roller over the intermediate transfer belt 3 is also increased, and the driving force of the intermediate transfer belt 3 is smaller than that in the state of FIG.

However, it has been clarified by experiments by the present inventors that in both states, a driving force twice as large as the load is required to stably drive the intermediate transfer belt. That is, in order to drive the intermediate transfer belt with the photosensitive belt 2, it is essential that the photosensitive belt pressing force be at least twice the dynamic friction force.

Accordingly, in order to ensure the driving force of the intermediate transfer belt 3, it is necessary to always apply a predetermined pressing force even if the mounting of the photosensitive belt 2 is repeated, as described later. 6, a holder 101 is provided at a predetermined position on the printer body side to support the driven roller shaft end 33 of the intermediate transfer belt 3 and the drive roller shaft end 23 of the photoreceptor belt 2, so that the horizontal Direction position Lh,
This is effective because the vertical position Lv can always be maintained with high accuracy.

Alternatively, as shown in FIG. 2, an auxiliary roller 33 is provided on the back surface of the intermediate transfer belt 3 on the upstream side of the contact portion 7.
Between the roller 33 and the driven roller 31, the photosensitive belt 2
A similar effect can be obtained even if the contact is made.

Further, as shown in FIG. 7, by providing a portion 25 coated with a rubber material along the circumferential direction in the non-image forming area on the surface of the photoreceptor belt 2, the A method of securing the frictional force of the intermediate transfer belt 3 and stabilizing the driving force of the intermediate transfer belt 3 is also an effective means. Since the coat portion 25 is located outside the image forming area W1, there is no need to worry about a change in the frictional force due to the entry of the toner.

Alternatively, as shown in FIG. 8, a similar effect can be obtained by providing a portion 35 coated with a rubber-based material in the non-image forming area on the surface of the intermediate transfer belt 3 along the circumferential direction.

Arranging the photosensitive member and the intermediate transfer member in a belt shape as described above can reduce the occupancy of each in the apparatus, and is an essential configuration for realizing a compact color laser printer. is there. For example, when the intermediate transfer body is constituted by a drum, the outer circumference of the intermediate transfer body needs to be 300 mm or more in order to form an image on A4 size paper. On the other hand, assuming that the intermediate transfer member is constituted by a belt having the same circumference and is stretched over by two rollers of φ30, the occupation ratio in the apparatus can be reduced to about 1/2 of that in the case of the drum. . In addition, if the belt is constituted by a belt, it is possible to use a wasteful space in the apparatus by bridging over a plurality of rollers, which is a very effective configuration for downsizing.

As shown in FIG. 1, the photoreceptor belt 2 and the intermediate transfer belt 3 are each stretched by two rollers, and the photoreceptor belt 2 is horizontally arranged, and the intermediate transfer belt 3 is connected to the photoreceptor belt. Is arranged in a direction perpendicular to the horizontal plane, and one of the rollers for bridging the photosensitive belt 2 is
And the developing device 6 and the exposure device 5 can be arranged on the upper surface of the photoreceptor belt 2 substantially in parallel with the vertical surface of the intermediate transfer belt 3. . Therefore, useless space generated when the photosensitive belt 2 and the intermediate transfer belt 3 are arranged can be minimized. The mounting density of each printing process is further increased by arranging the cleaning blade 8, the erase lamp 9, the charger 4 and the like substantially below the horizontal surface of the photoreceptor belt 2 in parallel.

On the other hand, since the developing device needs to be periodically replaced when the toner is consumed, it is desirable that the developing device be configured to be easily taken out from the apparatus main body and to be mounted. As described above, in this embodiment, since the developing device 6 is disposed on the upper surface of the photoreceptor belt 2 and substantially parallel to the vertical surface of the intermediate transfer belt 3, when the developing device 6 is removed from the apparatus main body, the upper portion of the main body is not shown. Is opened, and as shown in FIG.
It can be easily removed by pulling it out.
Further, when mounting, the cover can be easily mounted simply by opening the cover at the upper part of the main body and inserting the developing device 6 from above.

The photoreceptor belt 2 is also an element that needs to be periodically replaced, and it is desirable that the photoreceptor belt 2 be configured so that it can be easily taken out of the apparatus main body and mounted. In particular, it is essential to mount the photoreceptor belt so as not to damage the surface in order to form an image. In this embodiment, since the developing device 6 and the exposure device 4 are arranged on the upper surface of the photosensitive belt 2, the photosensitive belt 2
Is moved in the horizontal direction, which is a direction perpendicular to the mounting / removing direction of the developing machine 6, the mounting becomes possible without damaging the surface. Therefore, as shown in FIG. 9, the photoreceptor belt 2 has a cartridge structure, the cover (not shown) is opened, and the photoreceptor belt cartridge is mounted / removed in a horizontal direction, so that the photoreceptor belt can be easily replaced without damaging the surface. It is possible to do.

Here, the photosensitive member belt cartridge is mounted by setting the shaft end 23 of the drive roller 22 to the support member 100 of FIG. 5 or the support member 101 of FIG.
, And can be securely attached to the intermediate transfer belt 3 with a predetermined pushing amount.

When each unit is arranged as described above, the fed paper 16 is conveyed in the direction of the intermediate transfer belt 3 to transfer the toner image, and
Has to be brought into contact with the surface of the intermediate transfer belt 3 on the surface facing one of the rollers 31 over which the roller is bridged. Therefore, if the transfer roller 12 is disposed at this position, the paper 16
Then, the toner image can be reliably transferred to the sheet 16 without disturbing the toner image due to the contact between the toner image and the intermediate transfer belt 3.
That is, since the transfer roller 13 can be disposed by using the roller 31 that bridges the intermediate transfer belt 3, it is not necessary to newly provide a member facing the transfer roller 13, and the configuration can be simplified.

The sheet on which the toner image has been transferred is placed on the back side of the intermediate transfer belt 3 (here, the intermediate transfer belt 3).
(The side opposite to the side on which the photoreceptor belt 2 is disposed) across the intermediate transfer body belt 3
Is fixed by a fixing device 14 also arranged on the back side and discharged outside the device. With such a structure, the paper 1
Reference numeral 6 denotes a transport path that draws a large arc. For this reason,
The cassette 10 can be used for various types of paper such as thick paper, postcards, etc., even if a commonly used manual paper feed is not provided.
, And can be conveyed.

With the above configuration, it is possible to always achieve good color registration in a color laser printer. In addition, the color laser printer can be reduced in size and the handleability can be improved.

[0062]

As described above, since the intermediate transfer belt and the photosensitive belt can be driven with high precision, it is possible to reliably realize the superposition of the toner images of each color, and to obtain a high quality image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the structure of one embodiment of a color electrophotographic apparatus according to the present invention.

FIG. 2 is a schematic diagram illustrating another embodiment of the color electrophotographic apparatus of the present invention.

FIG. 3 is a diagram illustrating an experimental result of a driving force of an intermediate transfer belt by a photosensitive belt.

FIG. 4 is a diagram illustrating a contact portion between a photosensitive belt and an intermediate transfer belt.

FIG. 5 is a diagram illustrating a contact portion between the photosensitive belt and the intermediate transfer belt.

FIG. 6 is a view for explaining a joint portion of a photoreceptor belt and an intermediate transfer member belt in the present invention.

FIG. 7 is a diagram for explaining a contact portion between a photoreceptor belt and an intermediate transfer member belt in the present invention.

FIG. 8 is a view for explaining a contact portion between the photoreceptor belt and the intermediate transfer member belt in the present invention.

FIG. 9 is a schematic diagram for explaining attachment and detachment of a regular replacement product in the color electrophotographic apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Color laser printer, 2 ... Photoreceptor belt, 21
... Driving roller, 22 ... Driving roller, 25 ... Rubber coated part, 3 ... Intermediate transfer belt, 31 ... Driving roller, 32 ... Driving roller, 35 ... Rubber System coat part, 4
... Electric charger, 5 ... Optical device, 6 ... Developing machine, 61 ... Yellow developing machine, 62 ... Magenta developing machine, 63 ...
Cyan developing machine, 64 ... Black developing machine, 7 ...
Contact part between photoreceptor belt and intermediate transfer belt, 8 blade, 9 erase lamp, 10 paper cassette, 1
DESCRIPTION OF SYMBOLS 1 ... Paper feed roller, 12 ... Registration roller, 13 ... Transfer roller, 14 ... Fixing machine, 15 ... Cleaner, 16 ...
Paper, 17: paper discharge unit, 101: holder

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Akira Sasaki 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture F-term (reference) 2H030 AA06 AA07 AB02 AD05 BB23 BB42 BB63 2H032 BA01 BA09 BA23 2H035 CA05 CB06 CD02 CD05 CD11 CD14 2H071 BA03 BA13 BA42 DA08 DA09 DA12 DA16 DA22

Claims (8)

[Claims] 1. A color belt comprising: a photoreceptor belt driven by a driving unit; and an intermediate transfer member belt partially contacting the photoreceptor belt and transferring a toner image on the photoreceptor belt at the contact portion. In the electrophotographic apparatus, the intermediate transfer belt is stretched up and down by at least two rollers, and comes into contact with the photoconductor belt on a surface stretched in a vertical direction. And a support member that supports a shaft of a drive roller that drives the photosensitive belt so that the intermediate transfer belt can contact the photosensitive belt with a predetermined pressing force, and the intermediate transfer belt rotates following the drive of the photosensitive belt. Color electrophotographic apparatus. 2. The color electrophotographic apparatus according to claim 1, wherein the pressing force of said photosensitive belt against said intermediate transfer belt is at least twice the dynamic friction force between said intermediate transfer belt and said photosensitive belt. A color electrophotographic apparatus, wherein the photosensitive belt and the intermediate transfer belt are arranged. 3. The color electrophotographic apparatus according to claim 1, wherein a non-image forming area at both ends in the width direction of said photosensitive belt is coated with a rubber-based high friction material. 4. The color electrophotographic apparatus according to claim 1, wherein a non-image forming area at both ends in the width direction of said intermediate transfer belt is coated with a rubber-based high friction material. 5. The color electrophotographic apparatus according to claim 1, further comprising a transfer means for transferring a toner image to a transfer material, facing a lower roller which passes over said intermediate transfer member belt. Color electrophotographic apparatus. 6. A color electrophotographic apparatus according to claim 1, wherein said exposure means forms an electrostatic latent image on said photosensitive belt substantially parallel to a surface of said intermediate transfer belt that contacts said photosensitive belt. And a transfer material housing for arranging a plurality of developing means for developing the electrostatic latent image into a toner image, and for storing a transfer material such as paper on the opposite side of the developing means and the exposing means with the photosensitive belt therebetween. A color electrophotographic apparatus, wherein a cassette is arranged, and a fixing unit for fixing the toner image on the transfer material is arranged on the opposite side of the developing unit with the intermediate transfer belt therebetween. 7. The color electrophotographic apparatus according to claim 1, wherein said exposure means for forming an electrostatic latent image on said photoreceptor belt and a plurality of developing means for developing said electrostatic latent image into a toner image comprise: A color electrophotographic apparatus, wherein the photoconductor belt is disposed above a horizontal plane formed by being stretched by at least two rollers. 8. A color electrophotographic apparatus according to claim 1, wherein said plurality of developing means can be pulled out in a direction away from one surface of said photoreceptor belt, and said photoreceptor belt is moved in a direction away from one surface of said intermediate transfer member belt. A color electrophotographic apparatus characterized in that it can be pulled out of the apparatus.