JPH0413171A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate uneveness in feeding of a carrying belt and to prevent generation of image deviation or color deviation by providing in at least a roll imparting carrying force to the carrying means of the rolls retaining the carrying means with a cleaning means which cleans it. CONSTITUTION:When the developer splattered from developing devices 3a to 3d of image forming parts Pa to Pd is stuck on a transfer material mounting surface of a carrying belt 8, or the developer gathered from the photosensitive body drum 1a to 1d by cleaners 5a to 5d is splattered and stuck on the transfer material mounting surface of the carrying belt 8, cleaning is carried out by the cleaning means 107. Furthermore, when the developer eliminated at the cleaning means 107 of the carrying belt 8 floats and is stuck on the surface of the driving roll 11 driving the carrying belt 8, it is eliminated by the cleaning means 108. Therefore, reduction in frictional resistance between the carrying belt 8 and the driving roll 11 can be evaded. Thus, the uneveness in feeding is eliminated in the carrying belt 8, and the image deviation or the color deviation is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention generally relates to an image forming apparatus such as an electrophotographic method or an electrostatic recording method, but is not limited thereto. Color image formation in electrophotographic color copying machines, color printers, etc., in which a color image is obtained by sequentially transferring a visible image formed in a forming section onto a transfer material conveyed by an endless conveyance means such as a belt. It is suitable for the device.

1. Difficulty and I Color image forming apparatuses of various types have been proposed in the past, but one of them is to provide an image forming section for each color of developer, and an image carrier in each image forming section. An electrophotographic method in which a visible image of each color is formed on a photoreceptor drum using a well-known image forming process, and these visible images are sequentially transferred to a transfer material supplied from the outside and fixed all at once to obtain a color image. There are color image forming devices. In this case, the transfer material is placed on a conveyor belt that circulates endlessly and is sequentially conveyed to each image forming section, and the developed image formed on each photoreceptor drum is sequentially transferred to this transfer material.

In an image forming apparatus having such a configuration, the developer used to visualize the electrostatic latent image formed on the photoreceptor drum is scattered from the developing device that houses the developer. Or, the developer collected by the cleaner that cleans the developer remaining on the photoreceptor drum after transfer scatters from the cleaner and adheres to the transfer material placement surface of the conveyor belt, causing the transfer material placement surface to develop. It had the disadvantage of being contaminated with chemicals. Moreover, when the transfer material is a transfer paper, in addition to the above-mentioned stains, paper dust from the transfer paper further adheres to the transfer material mounting surface of the conveyor belt, making the stains worse. For this reason, various methods have been proposed for removing stains caused by developer, paper dust, etc. from the transfer material mounting surface of the conveyor belt.

If the transfer material mounting surface of the conveyor belt is extremely dirty, the dirt on the transfer material mounting surface can be removed using a cleaning device equipped with a fur brush, for example. However, the removed developer floats and adheres to the surfaces of the drive rollers that stretch and drive the conveyor belt.
It reduces the frictional resistance between the conveyor belt and the drive roller, causing the conveyor belt to slip in the direction perpendicular to the direction of travel. For this reason, there is a drawback that image height deviation and color deviation occur, resulting in deterioration of image quality. Further, an accident may occur in which developer overflows from a developing device or a cleaner for a photoreceptor drum within the apparatus, and the surface of the conveyor belt, drive roller, etc. may become severely contaminated. In this case, the surface on which the transfer material is placed can be cleaned by a cleaning device, but the surface of the drive roller must be cleaned or replaced by taking out the conveyor belt from inside the device, which has the drawback of requiring a great deal of effort and time for maintenance. there were.

Therefore, one object of the present invention is to eliminate the need to take out the conveyor belt from the apparatus and clean or replace it in order to remove dirt from the surface of the drive roller that drives the conveyor belt, thereby facilitating maintenance. An image forming apparatus is provided.

Another object of the present invention is to provide an image forming apparatus that prevents uneven feeding of the conveyor belt caused by providing a roller cleaning means on the drive roller that drives the conveyor belt, and prevents the occurrence of image shift, color shift, etc. caused by this. This is what we provide.

The above-mentioned object is achieved by an image forming apparatus according to the present invention. In summary, one aspect of the present invention includes an image carrier, and an endless moving unit that transports the transfer material to the image carrier in order to transfer the developed image formed on the image carrier to the transfer material. In an image forming apparatus having a conveyance means and a roller that holds the conveyance means, a cleaning means is provided for cleaning at least a roller that applies conveyance force to the conveyance means among the rollers that hold the conveyance means. An image forming apparatus with features is provided. According to another aspect of the present invention, an image carrier and an endlessly moving unit that transports the transfer material to the image carrier in order to transfer the developed image formed on the image carrier to the transfer material. An image forming apparatus having a conveyance means and a roller that holds the conveyance means, a cleaning means that cleans at least a roller that applies conveyance force to the conveyance means among the rollers that hold the conveyance means; a contacting/separating means capable of approaching and separating from the roller, and when the transfer material is carried by the conveying means, the contacting/separating means is controlled to cause the cleaning means to separate from the roller as well. An image forming apparatus is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view in which the present invention is applied to an electrophotographic color copying machine. In this embodiment, there are four image forming units Pa, P, first, second, third, and fourth in the copying machine main body 10.
b, Pc, and Pd, the present invention can be applied to an image forming apparatus including one or more image forming sections. A paper feed mechanism 13 is provided on one side of the copying machine main body 10, that is, on the right side in FIG. 1, and a transfer material discharge port 14 is provided on the opposite side, that is, on the left side in FIG. A fixing device 7 is disposed adjacent to and inside the discharge port 14 . In addition, below the path from the paper feed mechanism 13 to the fixing device 7 in the copying machine main body 1O, there is a driven roller means, that is, an idler roller 12 close to the paper feed mechanism 13; Drive side roller means, that is, drive rollers 11 are provided adjacent to the containers 7, respectively.
An endless conveyor member, for example a conveyor belt 8, is stretched between these rollers 11,12. Note that the drive roller 1
An adjustment roller 76 is provided below the conveyor belt 1 to freely adjust the tensile force of the conveyor belt 8 by coming into contact with the conveyor belt 8 from the inner peripheral side of the conveyor belt 8 . On the other hand, above the path from the idler roller 12 to the drive roller 11, the above-mentioned first, second, third, and fourth image forming sections are arranged in order from the paper feed mechanism 13 side close to the conveyance belt 8. Pa
, Pb, Pc and Pd are arranged in parallel.

The conveyor belt 8 is driven by a drive roller 11 in the direction indicated by the arrow in FIG.
b, Pc, and Pd. The paper feed mechanism 13 includes a paper feed cassette 51 that can be freely attached to and removed from the copying machine main body 10, a rotatable paper feed roller 52 provided in the section where the paper feed cassette 51 of the copy machine main body 10 is attached, and this paper feed roller. Transfer material 6 fed into the copying machine main body 10 by 52
a pair of registration rollers 80 that receive the transfer material 6 guided by the paper feed guide 53 and send it to the idler roller 12 at a predetermined timing; It is composed of a sensor (not shown) that outputs a predetermined signal when the leading end of the transfer material 6 is detected. This paper feeding mechanism 13 performs the function of placing the transfer material 6 onto the conveyor belt 8 from the idler roller 12 side. The fixing device 7 receives the transfer material 6 fed from the drive roller 11 side and fixes the image forming portions Pa, Pb,
The visual images transferred onto the transfer material 6 in Pc and Pd are fixed all at once to form a permanent image. A paper discharge tray 117 is attached to the transfer material discharge port 14 and is detachable from the copying machine main body 10 .

Each of the image forming units Pa, Pb%Pc and Pd has substantially the same configuration, and includes photoreceptor drums 1a, 1b, IC and 1d which are image bearing members that are rotationally driven in the direction of the arrow in the figure as usual. Chargers 15a, 15b, 15c, and 15 are provided around each photoreceptor drum to uniformly charge the photoreceptor drum.
d, developing devices 3a, 3b, 3c and 3d for developing the electrostatic latent image formed on the photosensitive drum; transfer dischargers 4a, 4b, 4C and 4 for transferring the developed visible image onto the transfer material 6;
d. Cleaning means 5a, 5b, 5c, and 5d for removing toner remaining on the photoreceptor drum are sequentially arranged in the drum rotation direction. In addition, each photoreceptor drum 1a, 1
Above the IC and 1d are imaging lenses 17a and 17b.
, 17c and 17d and laser beam scanner 16a
, 16b% 16c and 16d are provided, respectively.

The developing device 3a contains magenta toner, and the developing device 3b contains magenta toner.
contains cyan toner, developer 3C contains yellow toner, and developer 3d contains black toner. The laser beam scanners 16a, 16b
, 16c and 16d are composed of a semiconductor laser, a polygon mirror, an fθ lens, etc., and upon receiving an input of an electric digital pixel signal, a laser beam modulated in accordance with this signal is transmitted to the imaging lenses 17a, 17b, 17C and 17d, respectively. The drum surface is exposed by scanning in the drum generatrix direction between the chargers 15a, 15b, 15c, and 15d and the developing devices 3a, 3b, 3c, and 3d via the drum. The laser beam scanner 16a receives a pixel signal corresponding to a magenta component image of a color image, the laser beam scanner 16b receives a pixel signal corresponding to a cyan component image, and the laser beam scanner 16C receives a pixel signal corresponding to a yellow component image. , and pixel signals corresponding to the black component image are respectively input to the laser beam scanner 16d. Further, an adsorption charger (not shown) is provided between the first image forming section Pa and the paper feed mechanism 13, and this adsorption charger is used to charge the transfer material supplied from the paper feed mechanism 13. On the other hand, a static eliminator (not shown) is installed almost directly above the drive roller 11 between the fourth image forming section Pd and the fixing device 7. ) is provided, and an alternating current voltage is applied to this static eliminator in order to separate the transfer material 6 attracted to the conveyor belt 8. Sensors 60a, 60b, 60c, and 60d are disposed on the upstream side of each image forming section Pa, Pb, Pc, and Pd in the conveying direction, and these sensors are connected to the conveying belt 8.
When the leading edge of the transfer material 6 that has been conveyed by passes through, it is detected and the respective image forming portions Pa, Pb,
It is configured to output a signal for starting the image forming process in Pc and Pd to an electronic circuit control means, that is, a control unit.

In the color copying machine having the above configuration, a cut sheet-like material is used as the transfer material 6 as shown in the figure, and this transfer material 6 is sent out from the paper feed cassette 51 and sent to the paper feed mechanism 13.
When the paper moves within the paper feeding guide 53, its leading end is detected by the sensor (not shown), and a detection signal output from this sensor causes the photosensitive drums 1a, lb of each image forming section Pa, Pb%Pc, and Pd to be moved. , lc and Id start rotating. The drive roller 11 is also driven at the same time, and the conveyor belt 8 is driven in the direction of the arrow in FIG. Transfer material 6
When the sheet is guided by the paper feed guide 53 and placed on the conveyor belt 8, it is reliably attracted onto the conveyor belt 8 by corona discharge from the attraction charger (not shown). As the conveyor belt 8 moves in the direction of the arrow in FIG.
Each time the leading end of the photoreceptor drum passes through the detection area of each sensor 60a, 60b, 60c, and 6od, the image forming process for the corresponding photoreceptor drum 1a, 1b, 1c, and 1d is sequentially started. , a magenta image on the photoreceptor drum 1a of the first image forming section Pa, a cyan image on the photoreceptor drum 1b of the second image forming section pb, a photoreceptor drum 1 of the third image forming section Pc, c has a yellow image,
Black images are formed on the photosensitive drums 1d of the fourth image forming section Pd, respectively. These image forming portions Pa.

The principle of image formation in Pb, Pc, and Pd is already known as the Carlson process, so its explanation will be omitted. As the conveyor belt 8 moves, the transfer material 6 is transferred to the first
~Photosensitive drum 1a of fourth image forming section P a -Pd
~1d sequentially and transported toward the fixing device 7, and is formed on the transfer material 6 by the transfer dischargers 4a, 4b, 4c, and 4d of each image forming section. The developed images of each color are sequentially superimposed and transferred to form a color image. After passing through the fourth image forming section Pd, the transfer material 6 is neutralized by the unillustrated static eliminator to which an alternating current voltage is applied, and is separated from the conveyor belt 8 . The transfer material 6 separated from the conveyor belt 8 is sent to the fixing device 7, and after the transferred visual image is fixed in the fixing device 7, it is ejected from the transfer material ejection port 14 to the paper ejection tray 117, where it is removed. One copy cycle ends.

In this embodiment, a cleaning means 107 is provided for cleaning dirt adhering to the transfer material mounting surface of the conveyor belt 8, which is the means for conveying the transfer material. A cleaning means 108 is also provided for cleaning the surface of the belt drive roller 11. These cleaning means 107 and 108 both have fur brushes 107a and 108a in frames 107b and 108b, and these fur brushes 107a and 108a are arranged in a direction substantially perpendicular to the moving direction of the conveyor belt 8 (the axis of the drive roller 11). The shaft center is set in a direction parallel to the shaft, and is rotated by a motor (not shown) connected to these shafts, so as to contact the conveyor belt 8 and the drive roller 11, respectively.

Since the present invention is configured as described above, each image forming section P
Even if the developer scattered from the developing devices 3a, 3b, 3c, and 3d of a, Pb, Pc, and Pd adheres to the transfer material placement surface of the conveyor belt 8, or is collected from the photoreceptor drum by each cleaner. Even if the developer scatters and adheres to the transfer material placement surface of the conveyor belt, the developer is cleaned by the cleaning means 107, so the disadvantage that the image is smudged by the developer adhering to the transfer material placement surface is avoided. Can be removed. Further, even if the developer removed by the conveyor belt cleaning means 107 floats and adheres to the surface of the drive roller 11 that drives the conveyor belt 8, the cleaning means 108 removes this adhered developer. The frictional resistance between the belt 8 and the driving roller 11 does not decrease, and therefore, slippage occurring in the conveyor belt 8 in the traveling direction or in a direction perpendicular to the traveling direction can be prevented. Furthermore, even if the developer overflows from the developing device or the photosensitive drum cleaner inside the machine and the surface of the conveyor belt or drive roller is significantly contaminated, it can be easily cleaned by the cleaning means 107 and 108, so that There is no need to take pressure off the belt and clean or replace the drive roller, making maintenance easier.

In the above embodiments, a fur brush type cleaning means is disclosed, but it goes without saying that other types of cleaning means, such as a blade type cleaning means, can be used and similar effects can be obtained.

By the way, when the roller cleaning means 108 is attached to the drive roller 11 that drives the conveyor belt 8 as shown in this embodiment, the conveyor belt 8 is caused by friction between the roller cleaning means 108 and the drive roller 11, vibration of the roller cleaning means 108, etc.
There is a possibility that new feeding unevenness may occur, which may cause new image shift or color shift. For this reason, in the present invention, the cleaning means 108 for the drive roller 11 is configured to be able to approach and separate from the drive roller 11.

2 and 3 show an example of the contact state of the cleaning means 108. FIG. 2 shows the fur brush 108a in contact with the drive roller 11, and FIG. 3 shows the fur brush 108a in contact with the drive roller 11.
08a is shown separated from the drive roller 11. The frame body 108b and the fur brush 108a are attached to be able to swing integrally around a swing shaft 81, and the fur brush 108a is rotated by swinging the frame body 108b when a solenoid 84, which is a driving source, is turned on and off. swings between a position in which it contacts the surface of the drive roller 11 shown in FIG. 2 and a position away from the drive roller 11 shown in FIG. That is, when no energizing voltage is applied to the solenoid 84, the plunger 84a of the solenoid 84 is in a freely movable state, so the frame body 108b is pivoted in the direction of the drive roller 11 by the return spring 83, as shown in FIG. The fur brush 10 is moved and held at a position in contact with the stopper shaft 82.
8a comes into contact with the surface of the drive roller 11. At this time, the plunger 84a is at the most protruding position. When the fur brush 108a rotates in this state, the surface of the drive roller 11 will be cleaned. On the other hand, when an energizing voltage is applied to the solenoid 84, the plunger 84a is driven and withdraws into the solenoid against the tensile force of the return spring 83, so that the frame 108b moves toward the solenoid as shown in FIG. The fur brush 108a pivots to the drive roller 1.
Move away from the surface of 1. As a result, the roller cleaning means 10
8 and the drive roller 11, which would cause a load on the belt drive motor, and vibrations of the roller cleaning means 108 are not transmitted to the drive roller 11.
There is no possibility that rotational unevenness will occur in the conveyor belt 8, and the possibility that new feeding unevenness will occur in the conveyor belt 8 can be eliminated.

When the transfer material 6 is not placed on the conveyor belt 8, the drive roller cleaning means 108 having the above-described structure cleans the surface of the drive roller 11 with a fur brush 108a as shown in FIG.
Clean it by touching it. Then, in the image forming process, when the transfer material 6 is placed on the conveyor belt, a voltage is applied to the solenoid 84 to move the fur brush 108a of the cleaning means 108 to the driving roller 1 as shown in FIG.
1 and stop cleaning. As a result, while the surface of the drive roller 11 is cleaned, there is no need to apply an extra load to the drive motor of the conveyor belt 8 during image formation, so that new uneven feeding of the conveyor belt 8 is prevented.

In the above embodiment, a solenoid was used as the drive source for the approach and separation mechanism of the drive roller cleaning means, but for example, a motor and a cam □
The same operation can be performed using . Accordingly, various means known in the art can be used. Further, in the above embodiment, the present invention was applied to an electrophotographic color copying machine using four image forming sections, but the present invention can also be applied to an electrophotographic color copying machine having an arbitrary number of image forming sections, an electrostatic recording method, etc. It goes without saying that the present invention can be applied to various image forming apparatuses including copying machines and printers. Further, the structure and arrangement of the conveyor belt cleaning means, drive roller cleaning means, etc., and the structure and arrangement of the cleaning means approaching and separating mechanism, etc. can be variously changed as necessary.

As explained above, the image forming apparatus according to the present invention does not prevent the developer from being exposed to light by the cleaner even if the developer scattered from the developing device of the first image forming section adheres to the transfer material mounting surface of the conveyor belt. Even if the developer collected from the body drum scatters and adheres to the transfer material placement surface of the conveyor belt, the developer that has adhered to the transfer material placement surface will be cleaned by the conveyor belt cleaning means. The drawback of smudging the image can be eliminated. Furthermore, even if the developer removed by the conveyor belt cleaning means floats and adheres to the surface of the drive roller that drives the conveyor belt, the attached developer is removed by the drive roller cleaning means, so that the conveyor belt and the drive roller are removed. The frictional resistance between the rollers does not decrease, and therefore the conveyor belt can be prevented from slipping in the direction of travel or in a direction perpendicular to the direction of travel. Furthermore, even if the developer overflows from the developing device or photoconductor drum cleaner in the device and the surface of the conveyor belt or drive roller is significantly contaminated, it can be easily cleaned by both of the cleaning means described above. There is no need to take out the belt and clean or replace the drive roller (this makes maintenance easier. Furthermore, since the drive roller cleaning means is configured to be able to come into contact with and separate from the drive roller, it is not necessary to remove the belt and clean or replace the drive roller. Since there is no friction between the drive rollers that would cause a load on the belt drive motor, and vibrations from the roller cleaning means are not transmitted to the drive rollers, there is no risk of uneven rotation of the drive rollers, and the conveyor belt has a new feed. It is possible to prevent unevenness from occurring.Therefore, it is possible to prevent deterioration of image quality such as image shift and color shift, resulting in high quality,
There are many remarkable effects such as the ability to obtain high-quality images.

Pa～Pd Copy machine body : Drive roller :solenoid :Transport belt cleaning means : Drive roller cleaning means : Image forming section

Claims (1)

[Scope of Claims] 1) an image carrier, and an endlessly movable conveying means for conveying the transfer material to the image carrier in order to transfer the visible image formed on the image carrier to the transfer material; An image forming apparatus having a roller that holds the conveying means, further comprising a cleaning means that cleans at least a roller that applies a conveying force to the conveying means, of the rollers that hold the conveying means. Device. 2) An image carrier, an endlessly movable conveying means for conveying the transfer material to the image carrier in order to transfer the visible image formed on the image carrier to the transfer material, and holding the conveying means. an image forming apparatus having a roller, a cleaning means for cleaning at least a roller that applies a conveyance force to the conveyance means among the rollers holding the conveyance means; and a cleaning means capable of moving toward and away from the roller. and a contact/separation means,
An image forming apparatus characterized in that when the transfer material is carried by the conveying means, the cleaning means is separated from the roller by controlling the approaching and separating means.