JPH06242643A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate the positioning and attaching of a process cartridge and to improve the accuracy of positioning to an exposure device. CONSTITUTION:The device is provided with an opening/closing part 10 that can be opened/closed with respect to the device main body 1, and a positioning groove 37 whose one end is open almost horizontally is formed on the side plate 12 of the opening/closing part. The process cartridge 20 can be held by the opening/closing part and the position of the photosensitive drum 26 is restricted by inserting the shafts 26a at both ends of the photosensitive drum 26 of the process cartridge 20 into the positioning groove and positioning them in the innermost part of the groove. Further, the position of the porocess cartridge 20 in the turning direction is controlled and positioned, by butting the positioning pin 40 of the upper surface of the process cartridge 20 against the bottom plate 13 of the opening/closing part. In addition, the exposure device 46 is attached to the opening/closing part 10 after positioned. Thus, the accuracy of the positioning between the exposure device and the process cartridge is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a facsimile machine.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, in order to facilitate cleaning, maintenance, etc., a photosensitive drum,
A charger, a developing unit, a cleaner, etc. arranged around it are unitized into a process cartridge, which can be taken in and out in the axial direction of the photosensitive drum with respect to the apparatus main body.
It is known that an exposure device provided with a beam scanning means for forming an electrostatic latent image on the photosensitive drum is also unitized so that it can be put in and taken out from the apparatus main body in a direction parallel to the axis of the photosensitive drum (for example, , Japanese Patent Publication No. 4-73591).

In order to form a good image in this type of image forming apparatus, it is necessary to accurately position the process cartridge incorporated in the apparatus main body and the exposure apparatus, and in the apparatus described in the above publication. The process cartridge is provided with positioning pins parallel to the axis of the photosensitive drum near both ends of the process cartridge, and a pin insertion hole for inserting the positioning pin on the exposure device side. Was inserted into the main body of the apparatus, and the positioning pin was inserted into a pin fitting hole on the exposure apparatus side, thereby performing positioning between the exposure apparatus and the process cartridge.

[0004]

However, in such a conventional apparatus, since the process cartridge is inserted in the axial direction of the photosensitive drum, it has to be inserted in a narrow space,
In addition, at that time, it is necessary to insert a positioning pin, which is in an invisible position, into the pin fitting hole, which makes it difficult to insert the process cartridge. In addition, when the process cartridge is taken in and out, it is necessary to retract a part of the member provided on the apparatus main body side, which requires a mechanism for that and complicates the apparatus structure. Further, there is a problem that the positioning between the process cartridge and the exposure device is unstable only by fitting the positioning pin and the pin fitting hole.

The present invention has been made in view of the above-described problems, and provides an image forming apparatus having a simple structure and a reliable positioning with respect to an exposure device, although the process cartridge can be easily attached. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, is provided with an opening / closing portion that can be opened and closed with respect to an apparatus main body, and a process cartridge and an exposure device are attached to the opening / closing portion. The process cartridge is provided with first positioning means on both sides of the process cartridge so as to project on the same axis, and on the other hand, the opening / closing part is provided with an engaging portion for engaging the first positioning means for positioning. And a second positioning means for positioning the process cartridge and the opening / closing part in the rotational direction with respect to the opening / closing part of the process cartridge centering on the first positioning means inserted in the positioning groove. Be prepared.

Here, it is preferable that the first positioning means provided in the process cartridge is constituted by a shaft of the photosensitive drum.

Further, it is preferable that the second positioning means comprises a positioning pin provided on the upper surface of the process cartridge and an abutment surface provided at a position of the opening / closing portion which abuts on the positioning pin.

Further, when the process cartridge has a photoconductor unit having a photoconductor drum and a developing unit rotatably connected to the photoconductor unit and having a developing roll, the first positioning means. And it is preferable to provide the second positioning means on the photoconductor unit.

In the above apparatus, the direction of the positioning groove formed in the opening / closing portion is such that the opening / closing portion is closed and a drum gear drivingly connected to the photosensitive drum of the process cartridge is engaged with the driving gear provided in the apparatus main body. It is preferable that the direction of the force acting on the process cartridge via the drum gear when the gear is rotationally driven by the gear is determined so as to be the direction in which the first positioning means is engaged.

[0011]

According to the present invention, with the above-described structure, with the opening / closing portion opened, the positioning grooves formed on both sides of the opening / closing portion are
From the open end side, the first positioning means on both sides of the process cartridge is inserted, positioned at the engaging portion, and the process cartridge is rotated around the first positioning means, and the position determined by the second positioning means is reached. By doing so, the process cartridge can be accurately positioned with respect to the opening / closing portion, and can be accurately positioned with respect to the exposure device attached to the opening / closing portion. After attaching the process cartridge to the opening / closing part,
Only by closing the opening / closing portion, the process cartridge and the exposure device can be brought to a predetermined position with respect to the recording paper conveying means provided in the main body of the apparatus, and the process cartridge can be removed by the reverse operation. For this reason, the mounting work and the positioning work of the process cartridge are extremely easy.

Here, as described above, it is preferable that the first positioning means provided in the process cartridge is constituted by the shaft of the photosensitive drum because the positioning accuracy of the most important photosensitive drum is increased.

Further, if the second positioning means is composed of the positioning pin provided on the upper surface of the process cartridge and the contact surface provided at the position of the opening / closing portion that abuts against the positioning pin, the positioning can be performed only by the contact between them. , Easy to position.

Further, when the photoconductor unit and the developing unit constituting the process cartridge are rotatably connected, if the first positioning means and the second positioning means are provided in the photoconductor unit, the positioning accuracy is improved. It is possible to accurately position the photoconductor unit on the side required.

Further, the direction of the force acting on the process cartridge via the drum gear when the drum gear provided in the process cartridge is rotationally driven by the drive gear on the apparatus main body side is the direction in which the first positioning means engages. According to the above, the drive gear rotationally drives the drum gear during operation of the apparatus, and acts so as to press the first positioning means of the process cartridge against the engaging portion.
Therefore, the position of the process cartridge does not change and the positioning accuracy can be maintained at all times.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention shown in the drawings will be described below.

FIG. 1 is a schematic sectional view showing an image forming apparatus according to an embodiment in which the present invention is applied to a facsimile machine.
In FIG. 1, reference numeral 1 denotes a main body of the apparatus, a paper feed cassette 3 that accommodates a large number of recording papers 2 therein, a paper feed roller 4 that feeds the recording papers out of the paper feed cassette 3, and a recording paper to a photosensitive drum described later. Register roller 5 for feeding the toner image onto the recording sheet from the photosensitive drum, fixing roller 7 for fixing the toner image on the recording sheet, discharge roller 8 for discharging the recorded recording sheet, recording A paper guide 9 and the like are provided. The paper feed roller 4, the registration roller 5, the fixing roller 7, the discharge roller 8, and the recording paper guide 9
And the like constitute a conveying unit that conveys the recording paper along a predetermined path.

Reference numeral 10 denotes an opening / closing section which is provided above the conveyance path of the recording paper and which can be opened / closed with respect to the apparatus main body 1 around the support shaft 11. As shown in FIGS. 2 to 4, the opening / closing section 10 includes side plates 12 on both sides and the side plates 12, 12.
A bottom plate 13 provided between and a cover 1 provided on the upper surface
4 and a latch claw 1 rotatably attached to the side plate 12.
5 and a latch spring 16 and the like.
By hooking 5 on the latch pin 17 provided in the apparatus body 1, the apparatus body 1 is positioned at a predetermined position. An opening / closing spring 18 is provided on the support shaft 11 to urge the opening / closing portion 10 in the opening direction.

A process cartridge 20 is attached to the lower surface of the bottom plate 13 of the opening / closing section 10 while being positioned at a predetermined position. FIG. 5 shows this process cartridge 20.
FIG. 6 is a schematic side view showing the process cartridge 20 with the process cover removed. Figure 1
5 and 6, the process cartridge 20
Includes a photoconductor unit 21, a developing unit 22, a process cover 23, and the like. Photoconductor unit 21
Includes a photoconductor unit housing 25 and a photoconductor drum 26, a charger 27, a cleaner 28 and the like held by the photoconductor unit housing 25. On the other hand, the developing unit 22 holds a developing unit housing 31 in which a toner storage portion 30 is formed and the developer unit housing 31. The developing roller 32 and the like are provided.

As can be seen from FIG. 6, the photoconductor unit 21 and the developing unit 22 are rotatably connected to each other about a support shaft 34, and a spring 35 connects the two units 21 and 22 to the photoconductive drum. It is assembled by urging it to a position where it abuts against the developing roller.
Further, as can be seen from FIG. 5, the process cover 23
Is fixed to the developing unit 22 by screws 36.
The process cartridge 20 has this configuration in order to easily divide the process cartridge 20 so that the photosensitive drum can be replaced and the developing roller can be cleaned. Note that the process cartridge used in the present invention is not limited to this configuration, and may be one in which the photoconductor unit housing, the developing unit housing, and the process cover are integrated.

The shaft 26a of the photosensitive drum 26 attached to the process cartridge 20 is provided with the photosensitive unit housing 2
5, which protrudes outward from the wall surfaces on both sides of 5, and constitutes a first positioning means for positioning the process cartridge with respect to the opening / closing portion. On the other hand, as can be seen from FIGS. 2 to 4, the shafts 26 are provided on the side plates 12 on both sides of the opening / closing section 10.
A, that is, an engaging portion for inserting and positioning the first positioning means, that is, a positioning groove 37 whose one end is open is formed. When the shaft 26a is inserted into the innermost part of the positioning groove 37, the process cartridge 20 is closed by the opening / closing part 10.
The position is determined to be a predetermined position with respect to. Thus, as shown in FIG. 3, with the opening / closing portion 10 opened, the process cartridge 20 is moved in the direction indicated by the arrow A or in the opposite direction to move the shaft 26a into the positioning groove 3
Process cartridge 2
0 can be attached / detached to / from the opening / closing part 10, and the shaft 26a of the process cartridge 20 and thus the photosensitive drum 2 can be set by setting the shaft 26a at the innermost position of the positioning groove 37.
6 can be positioned in place. It should be noted that the positioning groove 37 is arranged such that the shaft 26a inserted therein is always positioned at the innermost position of the positioning groove 37 even when the opening / closing part 10 is closed at a predetermined position with respect to the apparatus body 1 as shown in FIG.
It is preferable to provide a slight inclination so that the inner side becomes lower. Further, instead of this, a spring for urging the shaft 26a toward the inner side of the positioning groove 37 may be provided.

As described above, the process cartridge 2
No. 0 is attached by inserting the shaft 26a into the positioning groove 37 of the opening / closing part 10, but the process cartridge 20 can be mounted on the shaft 26 only by engaging the shaft 26a and the positioning groove 37.
It can rotate around a, and its position in the direction of rotation cannot be regulated. Therefore, in order to regulate this position, as shown in FIG. 1, the positioning pin 4 is provided on the upper surface of the process cartridge 20 (strictly speaking, the upper surface of the photoconductor unit housing 25).
0 is provided so that when the process cartridge 20 rotates clockwise about the shaft 26a due to its own weight, it abuts against the lower surface of the bottom plate 13 of the opening / closing section 10 and stops at a predetermined position. Therefore, the positioning pin 40 and the contact surface (the lower surface of the bottom plate 13) with which the positioning pin 40 abuts are the second positioning for performing the positioning in the rotational direction with respect to the opening / closing part of the process cartridge centering on the first positioning means inserted in the positioning groove. Constitutes a means. Instead of providing the positioning pin 40 on the photoconductor unit housing 25, the process cover 23 is directly abutted on the bottom plate 13 or the process cover 23 is provided with a positioning pin and the positioning pin is abutted on the bottom plate 13 for positioning. However, the configuration of the embodiment is preferable because the positioning accuracy is high. Further, if necessary, a spring for urging the process cartridge 20 in the clockwise direction may be provided to ensure that the positioning pin 40 abuts the bottom surface 13.

The photosensitive drum 26 includes a drum gear 42 (see FIG. 6).
(See) is provided. On the other hand, as shown in FIG. 2, in the apparatus main body 1, a drive gear 44 arranged at a position where it meshes with the drum gear 42 when the opening / closing part 10 is closed and a drive device such as a drive motor for driving the drive gear 44 (not shown). ) Is provided. Thus, when the opening / closing part 10 is closed, the drive gear 44 meshes with the drum gear 42 and the photosensitive drum 2
6 can be rotationally driven. Here, as shown in FIG. 2, the drive gear 44 rotates in the direction of the arrow to rotate the drum gear 4
The shaft 2 that holds the drum gear 42 when the shaft 2 is rotated
A force in the direction indicated by arrow B acts on 6a. The positioning groove 37 for accommodating the shaft 26a is formed such that the acting direction of this force is the direction toward the back of the groove. Therefore, when the drive gear 44 rotates the drum gear 42, the shaft 2
A force in the direction of arrow B is applied to 6a to push the shaft 26a into the innermost position of the positioning groove 37. From this point as well, it is possible to prevent the shaft 26a from being held at the innermost position of the positioning groove 37 during the recording operation and changing the position of the photosensitive drum 26 to disturb the image. Incidentally, the developing roll 32 is also provided with a gear 45 (see FIG. 6) for driving the developing roll 32, so that when the opening / closing part 10 is closed, the developing roll 32 meshes with a driving gear (not shown) provided on the apparatus main body side. Has become. The rotation direction of this drive gear is also set so that a force in the direction of arrow B in FIG.

In FIG. 1, on the bottom plate 13 of the opening / closing section 10, an exposure device 46 for exposing the surface of the photosensitive drum 26 to form an electrostatic latent image on the photosensitive drum 26 is positioned at a predetermined position by a positioning pin or the like. Installed.
As the exposure device 46, for example, a scanning means using a laser beam can be used. The mounting position of the process cartridge 20 attached to the opening / closing section 10 is
When the opening / closing part 10 is closed at a predetermined position with respect to the apparatus main body 1 at a position where the exposure device 46 attached at a predetermined position can expose the photosensitive drum 26 satisfactorily, the photosensitive drum 26 is correctly positioned on the conveyance path of the recording paper. It is set to be the position to do.

In FIG. 1, the cover 14 covering the upper surface of the opening / closing section 10 also serves as a document placing table for the transmitting section, and a transmitting section (not shown) is provided beside the opening / closing section 10. Has been.

Regarding the image forming apparatus having the above configuration,
The operation will be described below. In FIG. 1, the cover 14 of the opening / closing part 10 is removed, and the exposure device 46 is attached to the bottom plate 13 from above.
It is placed on top and positioned at a predetermined position on the bottom plate 13 using the positioning pins. Thereby, the exposure device 46 can be easily and accurately attached to the predetermined position of the opening / closing part 10.

Next, the opening / closing section 10 is set to the open position as shown in FIG. 3, the process cartridge 20 is moved in the direction of arrow A, and the shafts 26a on both sides thereof are opened in the positioning grooves 37 of the side plate of the opening / closing section 10. Insert it from the end, slide it as it is to feed it to the innermost position, and then release the process cartridge 20. As a result, the process cartridge 20 slightly rotates in the clockwise direction about the shaft 26a under its own weight, and the positioning pin 40 (see FIG. 1) is opened / closed.
It stops at the position where it hits the lower surface of the bottom plate 13. Thus, the process cartridge 20 can be positioned and attached to the opening / closing portion 10 at a predetermined position by an extremely simple operation. As described above, the exposure device 46
Is positioned at a predetermined position with respect to the opening / closing section 10, so that it means that the process cartridge 20 and the exposure device 46 are finally attached in a predetermined positional relationship.

After that, the opening / closing portion 10 is set to the closed position with respect to the apparatus main body 1 as shown in FIGS. 1 and 2, and the latch claw 15 is engaged with the latch pin 17 and fixed. As a result, the process cartridge 20 is positioned at a predetermined position with respect to the recording paper conveyance path provided in the apparatus main body 1. At this time, since the process cartridge 20 moves from above with respect to the transport path, it is not necessary to evacuate the parts provided on the main device side, and therefore the process cartridge 20 can be opened only by the operation of closing the opening / closing unit 10. It can be positioned and fixed in place. Even in this state, the process cartridge 20 and the exposure device 4
6 is maintained in a predetermined positional relationship with high accuracy.

After that, a normal electrophotographic recording operation is performed. That is, the photosensitive drum 26 rotates, the exposure device 46 forms an electrostatic latent image on the surface thereof according to the received information, and the developing roller 32 applies toner to make the electrostatic latent image visible and supply it. The paper roller 4 and the registration roller 5 supply the recording paper to the photosensitive drum 26 at a predetermined timing, and the transfer device 6 transfers the toner image from the photosensitive drum 26 to the recording paper.
After that, the fixing roller fixes the toner image on the recording paper, and the discharge roller 8 discharges the recorded recording paper. During this operation, as described above, the process cartridge 20 and the exposure device 46.
Since a predetermined positional accuracy is maintained by the opening / closing section 10, a high-quality electrostatic latent image can be formed on the photosensitive drum 26, and high-quality recording can be performed.

When a jam or the like occurs in the recording paper conveyance path, the upper part of the conveyance path can be opened greatly by opening the opening / closing section 10 upward as shown in FIG. It can be done easily. Further, the process cartridge 20 can be removed by simply pulling out the process cartridge 20 in the direction opposite to the arrow A in the state of FIG. 3, and the work is extremely easy.

Although the shafts 26a at both ends of the photosensitive drum are used as the first positioning means in the above embodiment, instead of this,
A pin may be provided so as to project at both ends of the process cartridge 20 and be located on the same axis parallel to the photosensitive drum 26, and the pin may be inserted into the positioning groove 37 as the first positioning means.

[0032]

As is apparent from the above description, according to the present invention, the process cartridge and the exposure apparatus are positioned and attached to the opening / closing portion which can be opened and closed with respect to the apparatus main body, and the process cartridge is positioned. In order to attach the first cartridge, the first positioning means is provided on both sides of the process cartridge so as to project on the same axis, and the first positioning means is inserted into the opening / closing part and engaged so as to be positioned. Further, the process cartridge and the opening / closing part are provided with second positioning means for positioning in the rotational direction with respect to the opening / closing part of the process cartridge centering on the first positioning means inserted in the positioning groove. Therefore, with the opening / closing part open, insert the process into the positioning groove formed on both sides of the opening / closing part from the open end side. Yuki by inserting the first positioning means of the cartridge on both sides, is located innermost of the engaging portion,
And, by rotating the process cartridge about the first positioning means and setting it to the position determined by the second positioning means, the process cartridge can be accurately positioned in the insertion direction and the rotation direction with respect to the opening / closing part, Therefore, the process cartridge and the exposure apparatus can be accurately positioned with respect to the exposure apparatus attached to the opening / closing section, and after the process cartridge is attached to the opening / closing section, the process cartridge and the exposure apparatus are simply closed by closing the opening / closing section. Can be set to a predetermined position with respect to the recording paper transporting means, and the process cartridge can be removed by the reverse operation, and the process cartridge can be attached and positioned by a simple operation. Moreover, the space between the process cartridge and the exposure device is always Can be kept in order accuracy, it has the effect that it is possible to perform high-quality image formation.

Here, if the first positioning means provided in the process cartridge is constituted by the shaft of the photosensitive drum, the positioning accuracy of the most important photosensitive drum becomes high, and it is possible to form an image of higher quality. Is obtained.

Further, if the second positioning means is composed of the positioning pin provided on the upper surface of the process cartridge and the contact surface provided at the position of the opening / closing portion that abuts against the positioning pin, the positioning can be performed only by the contact between them. The advantages that the positioning is easy and the structure is simple can be obtained. .

Further, when the photoconductor unit and the developing unit constituting the process cartridge are rotatably connected, if the first positioning means and the second positioning means are provided in the photoconductor unit, the positioning accuracy is improved. Therefore, it is possible to accurately position the photoconductor unit on the side required to perform high-quality image formation, and it is possible to form a high-quality image.

The direction of the force acting on the process cartridge via the drum gear when the drum gear provided on the process cartridge is rotationally driven by the drive gear on the main assembly side of the apparatus is used to determine the direction of the force applied to the process cartridge. If it is determined that the direction goes toward the back of the joint, the drive gear rotates and drives the drum gear during operation of the device.
This acts to press the first positioning means of the process cartridge into the depth of the positioning groove. Therefore, the position of the process cartridge does not change, and the positioning accuracy can be constantly maintained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a part of the embodiment by cutting at a position where an opening / closing part is a side surface.

FIG. 3 is a schematic cross-sectional view showing the same portion as FIG. 2 with an opening / closing portion open.

FIG. 4 is a schematic perspective view of an opening / closing portion of the above embodiment.

FIG. 5 is a schematic perspective view of a process cartridge used in the above embodiment.

FIG. 6 is a schematic side view showing the process cartridge with the process cover removed.

[Explanation of symbols]

 1 Device body 2 Recording paper 3 Paper feed cassette 4 Paper feed roller 5 Registration roller 6 Transfer device 7 Fixing roller 8 Ejection roller 10 Opening / closing part 12 Side plate 13 Bottom plate 15 Latch claw 17 Latch pin 20 Process cartridge 21 Photoconductor unit 22 Developing unit 23 Process Cover 26 Photosensitive drum 26a Shaft (first positioning means) 32 Developing roller 37 Positioning groove 40 Positioning pin 42 Drum gear 44 Drive gear 46 Exposure device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Wataru Sugimoto 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An apparatus main body, and the apparatus main body.
The recording medium is provided with a conveying unit that conveys the recording sheet along a predetermined path, an opening / closing section that is openable / closable with respect to the apparatus main body, and a photosensitive drum. A process cartridge attached to the opening / closing portion so as to be at a predetermined position with respect to the transport path, and an exposure device attached to the opening / closing portion to expose the photosensitive drum to form an electrostatic latent image on the surface thereof. ,
The process cartridge has first positioning means formed on both sides of the process cartridge so as to project on the same axis.
The opening / closing part has an engaging part that engages so as to insert and position the first positioning means, and the process cartridge and the opening / closing part are the first part inserted in the engaging part. An image forming apparatus comprising: second positioning means for positioning the process cartridge in the direction of rotation with respect to the opening / closing part of the process cartridge. 2. The image forming apparatus according to claim 1, wherein the first positioning means is constituted by a shaft of a photosensitive drum provided in the process cartridge. 3. The second positioning means comprises a positioning pin provided on the upper surface of the process cartridge and an abutment surface provided at a position of the opening / closing portion that abuts on the positioning pin. The image forming apparatus according to 1 or 2. 4. The process cartridge has a photoconductor unit having a photoconductor drum, and a developing unit rotatably connected to the photoconductor unit and having a developing roll. 2. The two positioning means are provided on the photoconductor unit.
The image forming apparatus according to any one of items 1 to 3. 5. An apparatus main body, and the apparatus main body,
Conveying means for conveying the recording paper along a predetermined path, an opening / closing part that can be opened and closed with respect to the apparatus main body, a photosensitive drum and a drum gear drivingly connected to the photosensitive drum are provided. A process cartridge attached to the opening / closing section so that the photosensitive drum is located at a predetermined position with respect to the recording paper conveyance path when closed, and an electrostatic latent image is attached to the surface of the photosensitive drum attached to the opening / closing section. The process cartridge has first positioning means formed on both sides thereof so as to project on the same axis, and the opening / closing part inserts the first positioning means. The device body has an engaging portion that engages so as to be positioned, and further, the device body is arranged at a position that meshes with the drum gear when the opening / closing portion is closed. A drive device having a gear, the direction of the force acting on the process cartridge via the drum gear when the drive gear transmits the rotation to the drum gear, and the direction in which the first positioning means engages. The image forming apparatus is characterized in that the engaging portion is defined so that.