JPH0217114B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field of the Invention> The present invention relates to an improvement in an electrophotographic copying apparatus using an endless sheet-like photoreceptor, and more particularly, the present invention relates to an improvement in an electrophotographic copying apparatus using an endless sheet-like photoreceptor, and more particularly, the present invention relates to an improvement in an electrophotographic copying apparatus using an endless sheet-like photoreceptor, and more particularly, The present invention relates to an electrophotographic copying apparatus in which a covering means covering an opening into which a photoreceptor is inserted is automatically closed.

<Technical Background of the Invention and its Problems> A conventional electrophotographic copying apparatus using an endless sheet-like photoreceptor is disclosed in, for example, Japanese Patent Laid-Open No. 55-93184. In such conventional electrophotographic copying apparatuses that use endless sheet-like photoreceptors, copying quality deteriorates due to deterioration of the characteristics of the sheet-like photoreceptor used, lifespan, etc. The sheet-like photoreceptor is replaced each time the process is performed. In addition, the photoreceptor is normally replaced through an opening provided on the side of the main body of the device, and in this case, care must be taken to cover this opening with a pre-exposure prevention cover during copying operations, etc. There is.

On the other hand, in order to easily deal with problems such as copy paper jams, the copying device is
For example, an electrophotographic copying device with a structure that can be divided into two parts and opened to face each other was published in Japanese Patent Publication No. 56-40827.
has been shown and put into practical use.

Therefore, when the endless sheet-like photoreceptor described above is used in such an electrophotographic copying machine that is divided into upper and lower halves, the sheet-like photoreceptor must be replaced by opening the pre-exposure prevention cover. However, it is common to forget to close the exposure prevention cover after replacing the photoconductor, and in such a situation, it is necessary to perform a later operation, such as closing the upper and lower bodies that are open, to prevent the previous exposure. There is a risk of damaging the exposure prevention cover, and even if it is not damaged, the copying operation may be performed with the pre-exposure prevention cover incompletely closed, resulting in incorrect copies being obtained. There was a risk of problems occurring.

<Object of the Invention> The present invention has been made for the purpose of providing a new electrophotographic copying apparatus that eliminates the above-mentioned conventional problems. The device has a structure in which the main body of the device is divided into a first main body and a second main body that can be relatively opened, and an endless sheet-like photoreceptor can be moved along a predetermined path on one main body side. A supporting drum unit, an opening for inserting the sheet-like photoreceptor into the drum unit, and cover means that can be opened and closed to cover this opening are provided, and an operating member is provided on the other main body side. Accordingly, the covering means is automatically closed by the operating member in response to the closing operation of the first body and the second body.

Further, according to an embodiment of the present invention, the covering means is a pre-exposure prevention cover, and this pre-exposure prevention cover is provided with two
It is configured to be automatically closed in response to the closing operation of the divided device body.

<Embodiment of the Invention> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing the entirety of an embodiment of an electrophotographic copying apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a document table which is movably provided on the main body of the copying machine and holds the document, 2 is an illumination device that illuminates the document on the document table 1, and 3 is a rotary conveyance device for transmitting reflected light from the document. This optical means includes a self-occurring lens and the like that projects the image onto the photoreceptor 4. The photoreceptor 4 is formed into an endless sheet, as will be described later, and before the image projection (exposure) step by the optical means 3, a corona discharger 5 is provided facing the photoreceptor 4. The photoreceptor 4 is uniformly charged with a specific polarity, and by imagewise exposure to the photoreceptor 4, an electrostatic latent image corresponding to the original to be copied is formed on the photoreceptor 4. This latent image is then developed in a developing/cleaning device 6 provided, and toner is attached thereto. Note that the developing/cleaning device 6
A cartridge 7 for replenishing toner is attached to the cartridge.

Further, a cassette 8 containing a large number of sheets of paper is removably installed in the main body of the copying apparatus, and a paper feed roller 9 is provided facing the sheets of the cassette. The paper feed roller 9 is driven in response to a paper feed signal from a control means (not shown) for controlling copying of the copying apparatus, and the paper in the cassette 8 is fed one by one. This paper feed is sent to a conveyance roller 10 and a conveyance timing control board 11,
The transport timing control plate 11 transports the paper to the transfer process in synchronization with the rotational position of the photoreceptor 4 so that the leading edge of the image on the photoreceptor 4 and the leading edge of the paper coincide in the transfer process. A corona discharger 12 that performs corona discharge from the back side of the paper is disposed facing the photoreceptor 4 at a position where the paper is fed (transfer position) coinciding with the image forming tip on the photoreceptor 4. Through this transfer process, the toner image formed on the photoreceptor 4 is transferred onto the paper, and the paper supporting the toner image is peeled off from the photoreceptor 4 and moved to a fixing roller disposed in a direction away from the photoreceptor 4. 13
After the toner image is fixed, the paper is discharged from the apparatus.

On the other hand, a static eliminator 14 and a static eliminator 15 are provided behind the transfer process position to face the photoreceptor 4, and the photoreceptor 4 is charged at the second stage after the transfer process after the static electricity is removed.
At the rotation point, the toner remaining on the surface is cleaned by facing the developing/cleaning device 6 and prepared for the next image formation.

This photoreceptor 4 is different from a normal cylindrical drum formed or supported by a large-diameter drive roller (large-diameter drum) 1 that constitutes a drum unit.
An endless sheet-like photoreceptor is held between the roller 6 and a small-diameter roller (small-diameter drum) 17 under tension. The drive roller 16 is fixed at a fixed position with respect to the main body of the copying apparatus, and is rotated by the rotational force of the drive means (main motor 18). Further, although the roller 17 provided opposite to the drive roller 16 is usually rotatably held at the position shown in the figure, when replacing the photoreceptor 4, as will be described later, the roller 17 is provided facing the drive roller 16. 16). Therefore, if the roller 17 is moved in the direction of the arrow, the rollers 16,
The tension state of the photoreceptor 4 held between the photoreceptors 17 and 17 is released, and the photoreceptor 4 can be replaced easily.

In particular, the photoreceptor 4 is formed into an endless shape by fixing the front and rear ends of the sheet-like photoreceptor with fixtures 19, as shown in FIG. Such a photoreceptor is deformable to some extent, and since the photoreceptor 4 has an endless shape, it is very easy to take out the photoreceptor 4 or insert it between the rollers 16 and 17, and after insertion, When the roller 17 is returned to its normal position, a suitable tension is applied to the photoreceptor 4 itself.
For example, the photoreceptor 4 is brought into close contact with the drive roller 16 without being lifted up. It goes without saying that the photoreceptor 4 may have an endless structure without connecting its front and rear ends as shown in FIG.

FIG. 3 is an external perspective view showing the open state of the copying apparatus embodying the present invention, which is structured to be able to be divided into a first main body and a second main body, and is configured to be openable and closable.

In FIG. 3, an upper frame unit 21 constituting the first main body is rotatable about a shaft 22.
It is pivotally supported by a lower frame unit 23 constituting the main body, and is held in the open position shown in FIG. 3 by a spring (not shown) or the like.

On the first main body side, there is a drum unit equipped with a document table 1, an illumination device 2, an optical means 3, a corona discharger 5, a developing/cleaning device 6, a cartridge 7, a static eliminator 14, a static eliminator 15, and a photoreceptor 4. A cassette 8, a paper feed roller 9, a transport roller 10, a transport timing control plate 11, a corona discharger 12, a fixing roller 13, and a paper discharge tray 25 are provided on the second main body side. The first main body and the second main body are configured to be openable along the paper conveyance path.

Reference numeral 26 designates a protective cover for the drum unit 24. The drum unit protective cover 26 is rotatably supported by a protrusion provided at the lower part of the opening 28 of the upper frame unit 21. It is adapted to be covered to act as a covering means for preventing pre-exposure. 27 again
is the front cabinet opening/closing lid of the main body of the copying machine;
This opening/closing lid 27 is rotatably supported on the upper part of the lower frame unit 23.

According to the embodiment of the present invention, when replacing the endless sheet-like photoreceptor 4 (master M), first open/close the front cabinet cover 2 of the main body of the copying apparatus.
7, open the upper frame unit 21 and lower frame unit 23 vertically, rotate the tension release lever 31 clockwise about the shaft 32 as shown in FIG. Move it to position b.

By this operation, the tension state of the photoreceptor 4 is released, as will be described later. Next, grasp the lock release lever 33 provided on the upper outer side of the drum unit protective cover 26 and pull it toward you to release the photoreceptor 4.
Open the drum unit protective cover 26 for preventing pre-exposure of (Master M) (at this time, the apparatus is in the state shown in FIG. 3).

The drum unit protective cover 26 also protects the photoconductor 4.
The structure is such that it cannot be opened unless the tension state is released. That is, photoreceptor 4 (master M)
If the tension acting on is not released,
The tension release lever 31 is in the state a (see FIG. 4), and in this state, the tip 31-a of the tension release lever 31 is in the state shown in FIG. As shown in FIG. 4 (I--I cross-sectional view), the drum unit protective cover 26 is engaged to prevent the drum unit protection cover 26 from opening.

Therefore, when the drum unit protective cover 26 is opened, the tension state of the photoreceptor 4 is released, and the old photoreceptor 4 (master M) is pulled out from the opening 28 of the upper frame unit 21 and inserted into the new endless shape. The photoreceptor 4 (master M) is inserted and the photoreceptor 4 is replaced.

In addition, when the cover 26 at the bottom of the back surface of the drum unit protection cover 26 is closed, the photoreceptor 4
A photoreceptor positioning member 35 is provided at a position facing the side end portion of the photoreceptor. Therefore, when the drum unit protective cover 26 that has been opened after replacing the old and new photoconductor 4 is closed, the drum unit protective cover 26 will be closed even if the new photoconductor 4 is not inserted into the normal position. The photoreceptor 4 is pushed in the insertion direction by the photoreceptor positioning member 35 provided on the back surface, and the photoreceptor 4 is inserted into a fixed position. That is, when the drum unit protective cover 26 is closed by rotating it around the shaft 36 in the direction of arrow D as shown in FIG. The photoreceptor positioning members 35 provided to face each other move in the direction of arrow C, and even if the photoreceptor 4 is not inserted into the normal position, the photoreceptor 4 is moved by the photoreceptor positioning members 35. The photoreceptor 4 is inserted and positioned at a predetermined position by being pushed in the direction of arrow C.

Note that if the tension release lever 31 is returned from position b to position a before closing the drum unit protective cover 26, the drum unit protective cover 26
is in a state where it cannot be closed. That is, before closing the drum unit protective cover 26, rotate the tension release lever 31 counterclockwise from position b to position a.
When the drum unit protective cover 26 is closed after being moved to the position, the tip 31-a of the tension release lever 31 comes into contact with the stop member 34, as shown in FIG.
This configuration prevents the photoreceptor 4 from being closed.
5, if tension is applied to the photoreceptor 4, the photoreceptor 4 will not be inserted into the regular position, but will remain in that position with the insertion position shifted, and the photoreceptor 4 will remain in that position and will not appear on the copied image. The inconvenience of a malfunction occurring can be prevented. In particular, when the tension release lever 31 is in the b position, the drum protection cover 26 can be closed, and in other words, the photoconductor 4 with no tension acting on the photoconductor 4 can move in the insertion direction. Only in this state can the drum protection cover 26 be closed, and then the tension release lever 31 is returned to position a to apply tension to the photoreceptor 4.

Further, as the photoreceptor positioning member 35 that functions as described above, it is suitable to use, for example, polyethylene terephthalate (PET) with a thickness of about 0.2 mm.

With the tension release lever 31 in position b, the drum unit protective cover 26 is closed, and then the tension release lever 31 is rotated back from position b to position a to apply tension to the photoreceptor 4.
Next, the upper frame unit 21 is pushed down to integrate with the lower frame unit 23, and the front cabinet opening/closing lid 27 is closed to complete the replacement of the photoconductor 4. According to the embodiment of the present invention, the drum unit is protected. Even if you forget to close the cover 26 or forget to apply tension to the photoreceptor 4 using the tension release lever 31, the upper frame unit 21 can be automatically removed by pushing down and combining it with the lower frame unit 23. Drum unit protective cover 2
6 is closed, and then the tension release lever 31 is rotated back from position b (tension release state) to position a (tension action state).

The specific structure will be explained below.

As shown in FIG. 8, a pressing member 41 is provided upright on the lower frame unit 23, corresponding to the drum unit protective cover 26, and serving as an operating member for the drum unit protective cover 26, which is a covering means. An inclined portion 41-a is formed at the upper end portion of the pressing member 41.

When the upper frame unit 21 is pushed down in the direction of the arrow and closed with the drum unit protective cover 26 open (FIG. 8), the inclined portion 26 of the drum unit protective cover 26 will open as shown in FIGS. 8 to 10. The drum unit protective cover 26 is closed while the inclined part 41-a of the pressing member 41 first comes into contact with the vertical part 41-a of the pressing member 41 (FIG. 9).
b, the upper frame unit 21 is firmly pressed in the direction of the arrow E, and the upper frame unit 21 is completely attached to the frame unit 23.
It is closed as shown in FIG. 10 before joining. At this time, the lock portion 33-a of the lock release lever 33 provided on the protective cover 26 is fitted into the lock hole 42 provided on the drum unit 24 and locked, as shown in FIG. The lock release lever 33 is rotatably attached to the drum unit protective cover 26 about a shaft 43.
Further, a force is applied in the direction of arrow F by the spring pressing member 33-b.

In this way, the drum unit protective cover 26 is always locked by the lock release lever 33 as shown in FIG.
The lock is locked in the closed state by the lock release lever 33, and the lock is not released unless the lock release lever 33 is pushed down and rotated counterclockwise. Therefore, the drum unit protective cover 26 is opened by pushing down the lock release lever 33 to remove the lock hole 42 formed in the drum unit 24 and pulling it toward the front.

Next, a configuration for applying and releasing tension to the photoreceptor 4 will be described with reference to FIGS. 12 and 13.

In this example, as a method for applying and releasing tension on the photoreceptor 4, a large diameter drum (large diameter drive roller) 16 is used.
This is done by changing the distance between the axes of the small diameter drum (small diameter roller) 17, and FIG. 12 is a perspective view showing an example thereof.

The large diameter drum 16 is held at a fixed position on the upper frame unit 21, as will be described later. On the other hand, the other end of the rotating shaft 51 (not shown) of the small diameter roller 17 is slidably supported through an elongated hole as will be described later. Further, the tip of a rotating shaft 51 shown in FIG. 12 is rotatably attached to a tension plate 52. The tension plate 52 has an L-shaped deformed elongated hole 53 as shown in the figure.
is formed, and one end of a shaft 54 passes through this elongated hole 53. Also, the tension plate 52
is provided with a pin 55, and a spring 57 is installed between the pin 55 and a hook plate 56 attached to the side plate of the drum unit 24 to apply tension from the small diameter drum 17. This spring 57 urges the tension plate 52 in the direction of arrow G in the state shown in FIG.
The small diameter drum 17 serves to provide tension. A connecting plate 5 is attached to the tip of the shaft 54 passing through the deformed elongated hole 53 of the tension plate 52.
8 is fixed, and the tension release lever 31 is
They are attached to the tip of the shaft 54 in the relationship shown in the figure. Further, a guide pin 59 passing through the L-shaped hole 53 of the tension plate 52 is fixed to the connecting plate 58.

Also, the tension release lever 31 of the above-mentioned members
A configuration other than this is provided on the other end side of the drum 17.

In the structure as described above, when removing the endless photoreceptor 4 from between the drums 16 and 17, as shown in FIG.
When rotated in the direction of arrow H, the connecting plate 58 fixed to the shaft 54 rotates around the shaft 54. At this time, the tension plate 52 is attached to the guide pin 59.
14, the L-shaped hole 53 moves to the right in the figure while being guided by the shaft 54, and is held in the state shown in FIG. Note that the amount of movement of the small diameter drum 17 at this time is the distance x between the shaft 54 and the guide pin 59. In this way, the tension plate 52 is
moves to the right using the guide pin 59 and the deformed elongated hole 53 as guides, and the large diameter drum 16 and the small diameter drum 1
The distance between the axes 7 and 7 is reduced, and the tension on the photoreceptor 4 is released.

The endless photoreceptor 4 inserted between the drums 16 and 17 in the state shown in FIG. 14 above can be easily taken out, and a new endless photoreceptor 4
is inserted between the drums 16 and 17 to replace the photoreceptor 4. After the insertion of the new photoconductor 4 is completed, if the tension release lever 31 is rotated counterclockwise in the opposite direction to that described above, the tension plate 52 will be guided to the left by the shaft 54 as the connecting plate 58 is rotated. and moves to the state shown in Fig. 13, and the drum 1
An endless photoreceptor 4 inserted between 6 and 17
Appropriate tension is applied to bring the photoreceptor 4 into close contact with each drum.

Next, with the tension release lever 31 forgetting to apply tension to the photoreceptor 4, the upper frame unit 21 is pushed down and combined with the lower frame unit 23, thereby automatically releasing the tension release lever 3.
1 will be explained. As explained above, this is an explanation of the automatic return of the tension release lever 31 when the drum unit protective cover 26 is closed.

As shown in FIG. 15, the lower frame unit 23 is provided with a projection member 60 at a position facing the tension release lever 31. Therefore, if the upper frame unit 21 is pushed down before applying tension to the photoreceptor 4, the protruding member 60 provided on the lower frame unit 23 will prevent the upper frame unit 21 from moving during the closing process. Therefore, the tip of the projection member 60 comes into contact with the right end of the tension release lever 31, and the tension release lever 31 rotates in the direction of arrow I as shown in FIG. 16, and the small diameter drum 17 moves from the C position to the D position. Then, remove the upper frame unit 21.
Tension is automatically applied to the photoreceptor 4 in response to the closing operation.

The above description is based on the state in which the drum unit protective cover 26 is closed, but it is possible that both forgetting to close the protective cover 26 and forgetting to apply tension to the photoreceptor 2 using the tension release lever 31 occur at the same time. Even if the upper frame unit 21 is assembled, the protective cover 26 is automatically closed, and the tension release lever 31 is then returned to its original position.
In other words, as is clear from the previous explanation, the tension release lever 31 is returned to its original position after the protective cover 26 is closed. The timing of the contact is with the upper frame unit 21.
The height of the projection member 60 is appropriately determined so that the protective cover 26 is in a closed state immediately before it is assembled into the completed frame unit 23.

Further, according to this specific example, one end (rear side) of the drum unit in the direction of the rotational axis is supported by the main body of the apparatus as a fixed end, and the other end (front side) is either a free end or a fixed end depending on whether the drum unit protective cover 26 is opened or closed. It is configured to be the end.

A specific example of the method for supporting the drum unit 24 will be described below.

As shown in FIG. 17, the drum unit 24 has a large-diameter drum 16 and a drum support body consisting of a drum unit support frame 61, a drum unit front cover 62, and a top plate 63 that connects and fixes both at a constant interval. The large diameter drum 17 is rotatably supported, and the drum unit 24
On the rear side, a small drum 17 is installed as shown in FIG.
In order to be able to move laterally, the support shaft 51 is inserted into a long hole 64 formed in the drum unit support frame 61 and rotatably attached to the rear tension plate 65, and guided through the long hole 64. It is configured to slide as An L-shaped deformed elongated hole 66 is formed in the rear tension plate 65, and the other end of the shaft 54 passing through the drum unit support frame 61 is inserted into this elongated hole 66. Also, the rear tension plate 6
A spring (not shown) is installed between the drum unit support frame 61 of the drum unit 24 and the drum unit 24 to apply tension to the small diameter drum 17. Further, one end of a connecting plate 67 is fixed to the tip of the shaft 54 passing through the deformed elongated hole 66 of the rear tension plate 65, and the rear tension plate 61 is fixed to the other end of the connecting plate 67. A guide pin 68 passing through the L-shaped hole 66 is fixed.

One end of the shaft 69 for supporting the large diameter drum 16 is connected to a bearing 7 provided on the drum unit support frame 61.
0, and the other end of the shaft 69 is supported by the drum unit front cover 6 as shown in FIG.
2 is rotatably supported.

Each member related to the rear tension plate 65 is located outside the drum unit support frame 61, and an opening 72 is formed in the rear frame 71 of the upper frame unit 21 to correspond to this protrusion. ing.

The bearing 70 that pivotally supports the shaft 69 for supporting the large diameter drum 16 is fixed to the drum unit support frame 61 as described above.
0 is the upper frame unit 2 as shown in FIG.
1, and the shaft 69 is supported by the rear frame 71. In this state, the drum unit 24 is cantilever-supported by the rear frame 71 via the shaft 69, but since it is unstable to hold it in the hand with only this shaft 69, the drum unit support frame 61 is supported by the rear frame 71. The drum unit 24 is fixed by screwing in multiple places with screws 73, and the entire drum unit 24 is attached to the rear frame 71 of the upper frame unit 21 on the rear side.
It will be supported on a cantilever.

On the other hand, the drum unit protective cover 26 attached to the upper frame unit 21 so as to be openable and closable is provided with bearings 74 and 75 corresponding to the shafts 69 and 54 for supporting the large diameter drum 16, respectively. When the unit protective cover 26 is closed, the shaft 69 and shaft 54 for supporting the large diameter drum 16 are
are fitted into bearings 74 and 75 provided on the drum unit protective cover 26, respectively.

Therefore, during the copying operation, that is, when the drum unit protective cover 26 is closed, the drum unit 2
4, the upper frame unit 21 securely supports the upper frame unit 21 on both sides. Further, when the drum unit protection cover 26 is open, the rear side of the drum unit 24 is supported in a cantilever manner by the upper frame unit 21, and the front side becomes a free end, making it possible to smoothly replace the photoreceptor 4.

Note that the bearing portions 74, 75 and the shafts 69, 54 are tapered as shown in FIG. 19 so that they can be easily fitted together.

<Effects of the Invention> As described above, according to the electrophotographic copying device of the present invention, in an electrophotographic copying device using an endless sheet-like photoreceptor, the device main body is divided into a first main body and a second main body. The drum unit has a structure that can be relatively opened, and has a drum unit that supports an endless sheet-like photoreceptor so as to be movable along a predetermined path on one main body side, and an opening into which the sheet-like photoreceptor is inserted. and a covering means that can be opened and closed to cover the opening, and an operating member is provided on the other main body side, and the operating member is configured to act in response to the closing operation of the first and second bodies. Therefore, since the cover means is configured to close, even if the cover means is forgotten to be closed at the end of the photoconductor replacement operation, the closing operation of the first body and the second body will close the cover means. The covering means is automatically closed and the covering means is not damaged. In addition, since the covering means is automatically and reliably closed in accordance with the closing operation of the first body and the second main body, troubles caused by forgetting to close the covering means can be prevented, and reliability can be improved. A high quality electrophotographic copying device can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the internal structure of an embodiment of an electrophotographic copying apparatus embodying the present invention, FIG. 2 is a sectional view depicting a specific example of an endless photoreceptor, and FIG. FIG. 4 is a plan view showing the operating position of the tension release lever; FIG. 5 is a cross-sectional view taken along line II in FIG. 4; FIG. 7 is a diagram showing the positioning operation of the photoconductor by the drum unit protective cover, FIG. 7 is a diagram showing the mechanism for inhibiting the closing of the drum unit protective cover, and FIGS. Diagram showing each process of closing operation of unit protective cover, 1st
1 is a diagram showing a locking mechanism of a drum unit protective cover, FIG. 12 is a perspective view showing a specific example of a mounting mechanism for an endless photoreceptor, and FIGS. 13 and 14 are
15 and 16 are side views for explaining the movement of the tension release lever in conjunction with the closing operation of the upper frame unit of the main body of the apparatus, respectively. FIG. 17 is a perspective view showing a specific example of a photosensitive drum unit, FIG. 18 is a side view showing a mounting mechanism of the drum unit, and FIG. 19 is a side view showing an example of a tapered shaft and bearing part. be. 4...Photoconductor, 16...Large diameter drum, 17...Small diameter drum, 21...Upper frame unit, 23...Lower frame unit, 24...Drum unit, 26...Drum unit protective cover, 31...Tension release lever, 33...Lock release Lever, 34...stopping member,
35... Photoreceptor positioning member, 41... Pressing member, 6
0... Projection member, 69, 74, 75... Bearing portion.

Claims (1)

[Scope of Claims] 1. An electrophotographic copying device using an endless sheet-like photoreceptor, wherein the device main body is divided into a first main body and a second main body and has a structure that can be opened relative to each other, A drum unit for supporting the endless sheet-like photoreceptor so as to be movable along a predetermined path on one main body side, an opening for inserting the sheet-like photoreceptor into the drum unit, and a device for covering the opening. a covering means that can be opened and closed; an operating member is provided on the other main body side; and the operating member closes the covering means in response to a closing operation of the first and second bodies. An electrophotographic copying device characterized by the following.