JPS62201465A - Process unit for copying machine - Google Patents

Abstract

PURPOSE:To prevent a copy image from reduction in quality by forming a recording paper carrier penetrated into a housing and passed through a gap between a photosensitive body and a transfer device. CONSTITUTION:The recording paper carrier 27 formed in the gap between the photosensitive drum 21 and the transfer device 24 is penetrated through the housing 26 and recording paper can be passed from the lower area of a developing device 23 to the lower area of a cleaning device 25. The upper side end part of the recording paper carrier 27 is connected to a carry-in port 26a formed on the housing 26 and the lower side end part of the carrier 27 is connected to a carry-out port 26b formed on the housing 26. In order to transfer a toner image to the recording paper carried from the outside of the housing 26 into the housing through the carry-in port 26a and carry the recording paper smoothly to the outside of the housing 26 through the carry-out port 26b, the carry-in port 26a is arranged adjacently to a position, i.e. a photosensitive drum 21, properly higher than the carry-out port 26b. Consequently, the copy image can be prevented from reduction in quality.

Description

Detailed Description of the Invention 3. Narrow-toned U of II (Field of Industrial Application) The present invention relates to a process unit that is used in a small, lightweight copying machine and is detachable from the copying machine main body.

(Prior art) Recently, electrophotographic copying machines have been subject to deterioration due to use.
Alternatively, a copying machine has been developed in which a photoreceptor, a developing device, etc., which wear out with use, are integrated and configured to be detachable from the main body of the copying machine, thereby making it easy to replace consumables and the like. for example,
Japanese Unexamined Patent Publication No. 59-61850 discloses a process unit 1'A in which a photoreceptor, a charging device, a developing device, and a cleaning device are integrated. The process unit does not include a transfer device, and the transfer device is attached to the main body of the copying machine. The lower part of the unit is defined by a recording paper transport path formed by a gap between a transfer device attached to the copying machine main body and a photoreceptor housed in the unit.

In such a process unit, when the process unit is installed in a copying machine main body, the surface of the photoreceptor and the transfer device must be opposed to each other via the recording paper conveyance path. On the other hand, when the process unit is removed from the copying machine main body, the photoconductor is placed inside the process unit housing in order to protect the surface of the photoconductor or to prevent the toner inside the process unit from scattering outside. The process unit needs to be hermetically sealed so that it is housed inside. For this reason, the above-mentioned Japanese Patent Application Laid-Open No. 59-61
In the process unit disclosed in Publication No. 850, a special drum cover is provided to cover the photoreceptor, and when installed in the main body of the copying machine, the cover is opened to expose the surface of the photoreceptor and face the transfer device. 3. Conversely, when the unit is removed from the main body of the copying machine, the surface of the photoreceptor is covered with this cover. Such a drum cover requires a complicated mechanism because it is opened and closed in a narrow space.

Also, the drum cover can be opened easily.

A user of the copying machine may accidentally touch the surface of the photoreceptor. When the drum cover is opened, toner may be scattered around.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to provide a simple structure that prevents the user from accidentally touching the surface of the photoreceptor. Therefore, it is an object of the present invention to provide a process unit for a copying machine that does not pose a risk of degrading the quality of copied images.

(Means for Solving the Problems) The present invention is a process unit that can be attached to and detached from a main body of a copying machine, and includes a photoconductor that is integrally fixed in the housing of the process unit, and
It has a charging device, a developing device, a cleaning device, a transfer device, and a recording paper conveyance path passing through the housing and between the photoreceptor and the transfer device, thereby achieving the above object. is achieved.

(Example) Examples of the present invention will be described below.

As shown in FIG. 1, a process unit 20 of the present invention is detachably attached to, for example, an electrophotographic copying machine main body 10. As shown in FIG. In the process unit 20.

The equipment necessary for the copying process is integrally housed within the housing 26. The devices necessary for the copying process include a photoconductor drum 21 as a photoconductor rotatably disposed in the center of the housing 26, and a charging device 22 disposed around the photoconductor drum 21. Developing device 23. Transfer device 2
4 and a cleaning device 25. The charging device 22 is located above the photosensitive drum 21. Developing device 23. Transfer device 24. The cleaning device 25 and the cleaning device 25 are sequentially arranged downstream from the charging device 22 in the rotational direction of the photoreceptor drum 21 . The transfer device 24 is located below the photoreceptor drum 21. A slit 26c is formed in the upper surface of the housing 26.

The slit 26c is located between the charging device 22 and the developing device 23. The life of the photosensitive drum 21 in the process unit 20 is approximately equal to the period required for the amount of toner in the developing device W23 to be completely consumed. Furthermore, the lifespan of the charging device 22 and the transfer device ff24 is approximately equal to the lifespan of the photosensitive drum 21. Furthermore, the capacity of the discharge toner tank in the cleaning device 25 is also
Stray toner generated during the above period can be accommodated.

A recording paper conveyance path 27 is formed in the gap between the photosensitive drum 21 and the transfer device 24 . The recording paper conveyance path 27 is
It passes through the housing 26 and allows the recording paper to pass from a lower area of the developing device 23 to a lower area of the cleaning device 25 . The upstream end of the recording paper conveyance path 27 is connected to an entrance 26a formed in the housing 26.

Further, the downstream end of the recording paper conveyance path 27 is connected to the housing 26.
The outlet 26b is connected to the outlet 26b formed in the outlet 26b. In order for the recording paper carried into the housing 26 from outside the housing 26 through the carry-in port 26a to be smoothly carried out from the carry-out port 26b to the outside of the housing 26 after the toner image has been transferred, the carry-in port 26a is used as a carry-out port. It is preferable that it be provided at a position appropriately higher than 26b (a position close to the photoreceptor drum 21).

An introduction plate 28 is provided on the upstream side of the recording paper conveyance path 27 . Further, on the downstream side of the recording paper transport path 27.

A derivation plate 29 is provided. The introduction plate 28 extends downstream from the lower edge of the loading bay 26a of the housing 26. The downstream end of the introduction plate 28 is connected to the photoreceptor drum 21.
It is slanted so that it approaches. The lead-out plate 29 extends upstream from the lower edge of the outlet 26b. The derivation plate 2
Similarly, the upstream end of the photoreceptor 9 is inclined so as to approach the photoreceptor drum 21 . A transfer device 24 is disposed between the introduction plate 28 and the extraction plate 29 so as to face the photosensitive drum 21 .

The copying machine main body 10 can be equipped with the process unit 20 having such a configuration. At the top of the copying machine main body 10.

A sliding document table 11 is provided. The document table 11 can slide in a direction perpendicular to the axis of the photoreceptor drum 210 mounted thereon. Below the document table 11.

An optical system 12 is provided. The optical system 12 scans the image of the original placed on the original table 11 onto the photosensitive drum 21 in the process unit 20 as the original table 11 moves.
is exposed to light through the slit 26c of the housing 26.

A recording paper conveyance path 13 is formed in the lower part of the copying machine main body 10 . The conveyance path 13 carries recording paper in a paper holder 14 mounted on the copying machine main body 10.

The paper is to be delivered onto the tray 15 via the recording paper transport path 27 of the process unit 2o mounted on the copying machine main body 10.

It is formed longitudinally through the copying machine main body 10. A fixing device 3o is provided on the downstream side of the recording paper conveyance path 13, and fixes the toner image on the conveyed recording paper to the recording paper.

(Operation) The copying operation of the copying machine in which the process unit 20 is attached to the copying machine main body 10 is similar to the copying operation of a conventional electrophotographic copying machine, and is as follows. Process unit 1-2
The surface of the photoreceptor drum 21 is uniformly charged by the charging device 22 at zero. Next, the image of the document 312 placed on the document table 11 is exposed by the optical system 12, and an electrostatic latent image corresponding to the document image is formed on the surface of the photoreceptor drum 21. The electrostatic latent image is developed with toner by the developing device 23. On the other hand, recording paper.

The paper passes through the transport path 13 and is introduced into the recording paper transport path 27 of the process unit 20 . At this time, the recording paper.

It is guided by the introduction plate 28 and comes into contact with the photosensitive drum 21 reliably. The toner image on the photosensitive drum 21 is
The image is transferred onto recording paper by the transfer device 24. The recording paper on which the toner image has been transferred is guided by a guide plate 29 and passed through an exit port 26.
b is carried out of the housing 26.

Then, it is sent to the fixing device 30 through the transport path 13.

Here, the toner image is fixed on the recording paper. The recording paper with the toner image fixed thereon is discharged onto the tray 15.

After the toner image is transferred to the recording paper, residual toner is removed from the photosensitive drum 21 by a cleaning device 25 .

The lifespans of the photosensitive drum 21, the charging device 22, and the transfer device 24 in the process unit 20 are determined to be approximately equal, and the amount of toner in the developing device 23 and the amount of discharged toner in the cleaning device 25 also correspond to the above-mentioned lifespan. Therefore, when the photoreceptor drum 21 reaches its service life limit, the entire process unit 20 is pulled out along the axial direction of the photoreceptor drum 21 and separated from the copying machine main body 10, and replaced with a new process unit 20. Can be replaced.

(Effect of the invention) The process unit of the present invention is thus constructed.

In addition to the photoreceptor, charging device, developing device, and cleaning device, the transfer device is also fixed in the housing as one unit.
Moreover, since the recording paper conveyance path is formed in the gap between the photoreceptor and the transfer device, there is no risk of the photoreceptor being exposed outside the housing. Therefore, when replacing the process unit, there is no risk of accidentally touching the surface of the photosensitive drum, and there is no risk of degrading the quality of the copied image. Further, there is no fear that the toner will be scattered around.

4. 'The P'Development'■ Fig. 1 is a longitudinal sectional view of a copying machine equipped with three process units of the present invention.

10... Copying machine main body, 12... Optical system, 13...
・Transport route.

20... Process unit, 21... Photosensitive drum, 22... Charging device, 23... Developing device, 24...
・Transfer device, 25...Cleaning device, 26...
Housing, 27...recording paper conveyance path.

that's all

Claims (1)

[Claims] 1. A photoreceptor which is a process unit that is detachable from the main body of the copying machine and is integrally fixed within the housing. A process unit for a copying machine, comprising: a charging device, a developing device, a cleaning device, a transfer device, and a recording paper transport path passing through a housing and between the photoreceptor and the transfer device.