JPH0560588B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (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 body.

(Prior Art) In recent years, electrophotographic copying machines have integrated photoreceptors, developing devices, etc. that tend to deteriorate or wear out with use, and are configured to be removable from the copying machine body to prevent wear and tear. Products have been developed that make it easier to exchange items. For example, Japanese Patent Application Laid-Open No. 59-61850 discloses a process unit that integrates a photoreceptor, a charging device, a developing device, and a cleaning device. The process unit does not include a transfer device, and the transfer device is attached to the copying body. 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 main body of the copying machine and a photoreceptor housed in the unit.

In such a process unit, when the process unit is installed in the main body of a copying machine, 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 main body of the copying machine, the photoconductor is removed from the housing of the process unit in order to protect the surface of the photoconductor or to prevent the toner inside the process unit from scattering to the outside. The process unit must be hermetically closed so that it is housed within the For this reason, the process unit disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 59-61850 is provided with a special drum cover to cover the photoreceptor, and when installed in the main body of the copying machine, this cover is opened and the photoreceptor is removed. The surface of the photoreceptor is exposed to face the transfer device, and 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.
In addition, the drum cover can be easily opened, so
The 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 conventional problems, and its purpose is to prevent the transfer device from being replaced at the same time and to protect the photoreceptor surface with a simple structure. It is an object of the present invention to provide a process unit for a copying machine that can be used without causing any risk of deteriorating the quality of copied images.

(Means for Solving the Problems) The present invention is a process unit that is removably attached to a copying machine body equipped with a transfer device, and includes a photoreceptor, a charging device, and a charging device that are integrally fixed in the housing.
A developing device, a cleaning device, a transfer chamber formed in an area below the photoconductor in the housing so that the transfer device is located inside when installed in the copying machine main body, and between the photoconductor and the transfer chamber. a recording paper conveyance path passing through the housing;
This achieves the above objective.

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

As shown in FIGS. 1 and 2, a process unit 20 of the present invention is attached to, for example, an electrophotographic copying machine main body 10. As shown in FIGS. The copying machine main body 10 is
The upper half 16 and the lower half 17 are rotatably supported by a pivot 19 with the upstream section 13a and downstream section 13b of the recording paper conveyance path as boundaries. The process unit 20 of the present invention is slid and attached to the upper half 16 from the side thereof.

The process unit 20 includes a photoreceptor drum 21 as a photoreceptor rotatably disposed in the center of a housing 26, a charging device 22, a developing device 23,
and a cleaning 25, which are integrally fixed to the housing 26. Charging device 2
2 is located above the photoreceptor drum 21. The developing device 23 is disposed downstream of the charging device 22 in the rotational direction of the photosensitive drum 21 . The cleaning device 25 is disposed upstream of the charging device 22 in the rotational direction of 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.

A transfer chamber 24 is formed in the lower part of the housing 26 . The transfer chamber 24 is located below the photosensitive drum 21. Photosensitive drum 2 in the transfer chamber 24
A recording paper conveyance path 27 is formed near the housing 26 so as to pass through the housing 26 . Therefore, the upstream side of the recording paper conveyance path 27 is connected to an inlet 26a formed in the housing 26, and the downstream side of the recording paper conveyance path 27 is connected to an outlet 26b formed in the housing 26. There is. The recording paper enters the housing 26 from the lower area of the developing device 23 along the recording paper conveyance path 27, receives a toner image there, and then heads from the housing 26 to the lower area of the cleaning device 25. transported. In order for the recording paper carried into the housing 26 from outside the housing 26 through the carry-in port 26a to have a toner image transferred thereon, the paper is smoothly carried out of the housing 26 from the carry-in port 26b.
It is preferable that it is provided at a position appropriately higher than the outlet 26b (a position close to the photoreceptor drum 21).

An introduction plate 28 is disposed on the upstream side of the recording paper conveyance path 27, and a lead-out plate 29 is disposed on the downstream side of the recording paper conveyance path 27. Introduction plate 28
extends downstream from the lower edge of the entrance 26 a of the housing 26 , and its downstream end is inclined upward so as to approach the photosensitive drum 21 .
The lead-out plate 29 extends upstream from the lower edge of the outlet 26b. The upstream end of the guide plate 29 is also inclined upward so as to approach the photosensitive drum 21 .

Photosensitive drum 2 in process unit 20
1 and the charging device 22 are approximately equal to the period required to consume the amount of toner stored in the developing device 23. Similarly, the capacity of the waste toner tank in the cleaning device 25 is such that it can accommodate the waste toner generated during the above period.

An opening 24 a is formed in the lower surface of the transfer chamber 24 formed in the lower part of the housing 26 .
The opening 24a connects the inside of the transfer chamber 24 and the housing 26.
communicate with the outside. The opening 24a has a size that allows a transfer device 18, which will be described later, to enter therein. For example, the opening 24a has two sealing members 24.
b, 24b can be opened and closed. The proximal end of each seal member 24b and 24b is connected to the opening 2.
They are each fixed to the opposing peripheral edges of 4a in a single-supported state. Each seal member 24b and 2
The tip portions of the openings 4b overlap at the center of the opening 24a. As the sealing member 24b, a material having light-shielding properties and flexibility, such as a plastic film, is used.

As described above, the process unit 20 can be attached to the upper half 16 of the copying machine main body 10, which rotates around the pivot shaft 19. A sliding document table 11 is disposed above the upper half 16.
The document table 11 can slide in a direction perpendicular to the axis of the photoreceptor drum 21 mounted thereon. Original table 11
An optical system 12 is disposed below. The optical system 12 exposes the image of the document placed on the document table 11 onto the surface of the photosensitive drum 21 in the process unit 20 through the slit 26c of the housing 26 as the document table 11 moves.

A transfer device 18 is attached to the lower half 17 of the copying machine main body 10 at a position facing the photosensitive drum 21. The transfer device 18 is connected to the copying machine main body 1
When the upper half 16 and lower half 17 of 0 are connected, the transfer chamber 24 in the process unit 20
Therein, sealing members 24b and 24 of opening 24a.
The seal members 24b and 24b enter the transfer device 18 while pushing it open, and the seal members 24b and 24b come into contact with the side surface of the transfer device 18. Therefore, the transfer device 18 and the opening 24a
The gaps between the transfer chamber 24 and the transfer chamber 24 are closed by the seal members 24b, and there is no possibility that external dust or the like will enter the transfer chamber 24 through the opening 24a.

Upper half 16 and lower half 17 of the copying machine main body 10
are separated by an upstream portion 13a and a downstream portion 13b of the recording paper conveyance path. When the upper half 16 and lower half 17 of the copying machine main body 10 are connected,
These transport paths 13a and 13b communicate with an inlet 26a and an outlet 26b of the housing 26 of the process unit 20, respectively. As a result, the upstream portion 13a of the recording paper conveyance path, the recording paper conveyance path 27, and the downstream portion 13b of the recording paper conveyance path communicate with each other. Therefore, the recording paper in the paper holder 14 of the copying machine main body 10 passes from the transport path 13a, through the recording paper transport path 27 of the transfer chamber 24, to the downstream part 13b of the transport path, and then passes through the tray 15 of the copying machine main body 10. It can be discharged upwards. During this time, the toner image is transferred onto the recording paper in the transfer chamber 24 of the housing 26. This transferred toner image is reflected on the reflection path 1.
The image is fixed on the recording by the fixing device 13c provided in the image forming apparatus 3b.

The process unit 20 is attached to the copying machine main body 10 in the following manner. First, the upper half 16 of the copying machine main body 10 is rotated upward and separated from the lower half 17. In this state, the process unit 20 is attached to the upper half 16. Then,
This upper half body 16 is rotated downward, and the lower half body 1
Connect to 7. In this case, the process unit 20
Seal members 24b, 24b close the transfer chamber 24 of
is pressed by the transfer device 18 attached to the lower half 17 of the copying machine main body 10 to open the opening 24a. The transfer device 18 has each seal member 24b, 2
It enters into the transfer chamber 24 while slidingly contacting the transfer chamber 4b. When the upper half 16 and the lower half 17 are connected, the transfer device 18 faces a predetermined position of the photoreceptor drum 21 across the recording paper conveyance path 27.

The copying operation of this copying machine is similar to that of a conventional electrophotographic copying machine, and is as follows.
A charging device 22 in the process unit 20 uniformly charges the surface of the photosensitive drum 21. Next, the image of the original placed on the original platen 11 is exposed by the optical system 12, and an electrostatic latent 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, the recording paper is introduced into the recording paper conveyance path 27 of the process unit 20 through the upstream portion 13a of the conveyance path. At this time, the recording paper is guided by the introduction plate 28 and brought into contact with the photosensitive drum 21. Photosensitive drum 21
The upper toner image is transferred onto the recording paper by the transfer device 24. The recording paper on which the toner image has been transferred is guided by the guide plate 29 and is carried out of the housing 26 from the outlet 26b. The toner image is then sent to the fixing device 13c through the downstream portion 13b of the conveyance path, where the toner image is fixed onto the recording paper. The recording paper with the toner image fixed thereon is discharged onto the tray 15.
When the toner image is transferred to the recording paper, the photosensitive drum 21 is cleaned by a cleaning device 25 to remove residual toner from the surface thereof.

Photosensitive drum 2 in process unit 20
1 and the charging device 22 are set 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 are also set to correspond to the above-mentioned lifespan. Therefore, the photoreceptor drum 2
When the first class reaches its service life limit, the upper half 16 of the copying machine main body 10 is rotated upward, and the process unit 2
0 is slid in the axial direction of the photoreceptor drum 21 and removed from the upper half 16. Then, a new process unit 20 is added to the upper half 1.
6. The process unit 20 separated from the upper half 16 is attached to the seal members 24b and 24.
Due to their own flexibility, the tips of the tips of the tips b are in an initial overlapping state, and the opening 24a of the housing 26 is opened.
occlude.

The process unit 20 of the present invention can also be applied to a copying machine whose main body 10 cannot be separated into an upper half 16 and a lower half 17. For a copying machine main body that cannot be separated into an upper half and a lower half, the process unit is attached to and removed from the copying machine main body by sliding in a direction perpendicular to the recording paper conveyance path in the copying machine main body. 3 to 5 show a process unit 20' of the present invention that can be attached to and detached from such a copying machine main body. In the process unit 20', an opening 24a' is formed on one side of a transfer chamber 24' in the sliding direction, which is formed in a region below the photosensitive drum 21' in the housing 26'. In the opening 24a', sealing members 24b' and 24b' made of the same material as in the previous embodiment are supported on opposite sides of the opening 24a, respectively. The tip of each seal member 24b' and 24b' is connected to the opening 24
They overlap at the center of a' and close the opening 24a'. An engaging portion 24d' that can engage with a locking portion 18b' (described later) of the transfer device 18' is provided on the inner surface of the transfer chamber 24' facing the opening 24a'.

The transfer device 18' is fixed to the copying machine main body 10' by a support member 18a'. The support member 18
a' supports one longitudinal end of the transfer device 18'. A locking portion 18b' is formed at the other longitudinal end of the transfer device 18'. The locking portion 18
b' can engage with an engaging portion 24d' within the transfer chamber 24'. Due to their engagement, the process unit 20'
is fixed at a predetermined position relative to the copying machine main body 10'. The other configurations are the same as those of the previous embodiment, so the explanation will be omitted.

The process unit 20' is attached to the main body of the copying machine in the following manner. The locking portion 1 of the transfer device 18' is inserted from the opening 24a' of the housing 26'.
8b' is inserted into process unit 2.
0' is moved into the main body 10' of the copying machine. As a result, the sealing member 24b' covering the opening 24a' is pushed open by the locking part 18b', and the transfer device 18'
enters the transfer chamber 24'. At this time, the seal members 24b' and 24b' are in contact with the outer surface of the transfer device 18' due to their own flexibility.
Then, the locking part 18a' of the transfer device 18' engages with the engaging part 24b' on the inner surface of the transfer chamber 24'.
The process unit 20' is mounted at a predetermined position with respect to the main body 10' of the copying machine.

Note that a member for guiding the transfer device 18' to a predetermined position may be provided in the transfer chamber 24' of such a process unit 20'.

(Effects of the Invention) As described above, in the process unit of the present invention, the transfer chamber in which the transfer device is located is formed below the photoreceptor fixed in the housing, with the recording paper conveyance path in between. Therefore, when the process unit is replaced, the photoreceptor is protected by the transfer chamber in which the transfer device that does not require replacement is located.
Therefore, even when the process unit is separated from the transfer machine main body, there is no risk of accidentally touching the surface of the photoreceptor, and the quality of the resulting copy image will not deteriorate. Further, the toner scattered from the photoreceptor is suppressed from scattering around the process unit by the transfer chamber.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the process unit of the present invention installed in the copying machine main body, FIG. 2 is a longitudinal cross-sectional view of the copying machine main body with the upper half rotated upward, and FIG. 4 is a front view of a process unit according to another embodiment of the present invention, FIG. 4 is a sectional view thereof, and FIG. 5 is a sectional view taken along the - line in FIG. 4. 10, 10'... Copy machine body, 18, 18'...
Transfer device, 20, 20'...process unit,
21, 21'...photosensitive drum, 22...charging device, 23...developing device, 24, 24'...transfer chamber,
24a, 24a'...opening, 24b, 24b'...sealing member, 25...cleaning device, 26,2
6'... Housing, 27... Recording paper conveyance path.

Claims (1)

[Scope of Claims] 1. A process unit that is removably attached to a copying machine body equipped with a transfer device, comprising: a photoreceptor, a charging device, a developing device, and a cleaning device that are integrally fixed within the housing; and the copying machine body. a transfer chamber formed in an area below the photoreceptor in the housing so that the transfer device is positioned therein when installed in the housing; and a recording paper conveyance that passes through the housing and passes between the photoreceptor and the transfer chamber. A process unit of a copying machine, comprising: a path;