JP2001109358A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing means which can fix and remove a process unit with small force linked with the loading/removing of the process unit. SOLUTION: A fixing means installed in a device main body fixing the pins of the process unit, which are inserted into the long holes of a pair of side walls, is arranged. The fixing means has a fixing member and an tension coil spring. The fixing member has first and second levers that can freely rock. The first lever presses the pin from outside when the pin of the process unit is engaged with the long hole. The second lever is pressed and rocked by the pin inserted into the long hole and makes the first lever rocks to a position where the pin is pressed. The tension coil spring is supported by a supporting body positioned on the side wall and a supporting body positioned in the first lever. When the first lever is in the pressing position along a direction where a line connecting the supporting body on the side wall and an axle crosses the longitudinal direction line of the long hole, a line connecting the supporting bodies is positioned on a side inner than the line connecting the supporting body on the side wall and the axcle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which a process unit is detachably provided.

[0002]

2. Description of the Related Art In an image forming apparatus such as a facsimile machine or a copying machine which adopts an electrophotographic system, after a latent image is formed by a photoreceptor in an image recording section, a charging device for stopping the surface of the photoreceptor, and an exposing device. Equipped with a process unit that integrates a developing device that forms a toner image on the surface of the photoconductor and a cleaning device that removes toner remaining on the photoconductor after transferring the toner image on the photoconductor to recording paper, as an integrated structure. The process unit is detachably mounted inside the apparatus main body, so that toner can be replenished or the photosensitive member that has reached its replacement time can be replaced, thereby improving the workability of maintenance and inspection.

Conventionally, in order to removably mount a process unit in an image forming apparatus in this image forming apparatus, a pair of side walls for inserting and removing the process unit from the upper side in the apparatus main body are provided with a gap therebetween. Elongated holes each having an open upper end are formed along the up-down direction, and pins are provided on both sides of the process unit so as to be engaged with and removed from the elongated holes of the pair of side walls. Some adopt a configuration in which fixing means for fixing the pin of the process unit engaged with the hole from above is provided.

That is, when the process unit is moved downward and inserted between the pair of side walls from above, the pins on both sides are engaged with the long holes of the pair of side walls from above and the entire process unit is supported and fixed. The means holds the process unit by pressing it so that it does not come out of the pin. Further, from this state, the process unit is moved upward and taken out from between the pair of side walls, and at this time, the pressing of the pins by the fixing means is released, and the pins on both sides thereof are pulled out from the long holes of the pair of side walls.

In such a conventional structure, as a fixing means, a pin engaged with the elongated hole is pressed in conjunction with an operation of inserting the process unit between the pair of side walls, and the process unit is held between the pair of side walls. A method is adopted in which the pin is removed from the elongated hole in conjunction with the operation of removing the pin from the slot. This is characterized in that the operation of inserting and removing the process unit and the pressing and releasing of the pin can be performed simultaneously, so that the operation can be performed efficiently. Conventionally, the fixing means adopting this method has the structure shown in FIG. I have. FIG. 7 is an explanatory view showing the operation of a fixing means for fixing a process unit in a conventional image forming apparatus.

In FIG. 7, reference numeral 1 denotes a side wall provided on the apparatus main body;
2 is a long hole formed in the side wall 1, 3 is a process unit,
Reference numeral 4 denotes a pin protruding from the process unit 3. Reference numeral 5 denotes a fixing member provided on the outer surface of the side wall 1, and reference numeral 6 denotes a tension coil spring. The fixing member 5 and the tension coil spring 6 constitute fixing means.

The fixing member 5 is located on one side of the elongated hole 2, supported by a pivot 7 parallel to the pin 4 so as to swing in a vertical plane, and engaged with the elongated hole 2. 4 is pressed, a triangular portion 5a protruding toward the elongated hole 2 is formed at the end serving as the upper end, and a tension coil spring 6 is connected to the end also serving as the lower end. Part 5a
Is applied to the long hole 2). The fixing member 5 comes into contact with a stopper (not shown) and stops in a state where the triangular portion 5a overlaps the elongated hole 2. Then, the process unit 3 is moved downward from above to move the pair of side walls 1.
When the pin 4 is inserted into the gap, the pin 4 also moves downward integrally and collides with the upper side 5b of the triangular portion 5a located at a position overlapping the slot 2. As the pin 4 moves downward along the vertical direction, the fixing member 5 swings counterclockwise due to a horizontal component force generated by the action of the inclined upper side 5b of the triangular portion 5a subjected to the downward moving force. Then, the triangular portion 5a is displaced in a direction away from the elongated hole 2. Pin 4 is triangular part 5a
When the fixing member 5 is inserted to the lower end of the long hole 2 over the top of the triangle, the fixing member 5 swings clockwise again and the lower side 5c of the triangular portion 5a presses the pin 4 from above. The pressing force in this case is a vertical component force acting downward by the action of the lower side 5c of the triangular portion 5a to which the spring force of the tension coil spring 6 is applied. When the process unit 3 is moved upward and taken out from between the side walls 1, the pins 4 move up integrally and press the lower side 5 c of the triangular portion 5 a located at a position overlapping the slot 2. As the pin 4 rises in the vertical direction, the fixing member 5 swings counterclockwise due to the horizontal component force generated by the action of the inclined lower side 5c of the triangular portion 5a receiving the rising force. As a result, the triangular portion 5a is displaced away from the long hole 2. When the pin 4 gets over the top of the triangular portion 5a and reaches the upper end opening of the long hole 2, the fixing member 5 swings clockwise again.

[0008]

The fixing means for pressing the pins of the conventional process unit has the following problems. When the process unit is loaded, the triangular portion 5a is caused by a horizontal component force generated by the action of the inclined upper side 5b of the triangular portion 5a which receives the downward moving force in the vertical direction by the process unit 3 and causes the triangular portion 5a to move. The fixing member 5 is swung in a direction away from the long hole 2. As described above, the vertical component of the force of the process unit 3 moving downward along the vertical direction is used as the force for swinging the fixing member. 3 utilizes only a small part of the downward moving force and cannot utilize many parts effectively. For this reason, the tension coil spring 6
In order to swing the fixing member 5 having received the spring force against the spring force, it is necessary to move the process unit 3 downward with a large force. Requires labor.

Similarly, when the process unit 3 is taken out, similarly, the vertical component of the force that the process unit 3 rises along the vertical direction is used as the force for swinging the fixing member. In order for the process unit 3 to swing in the release direction, only a small part of the rising force of the process unit 3 is used, and many parts cannot be effectively used. Therefore, in order to swing the fixing member 5 having received the spring force of the tension coil spring 6 against the spring force, it is necessary to raise the process unit 3 with a large force. Requires great power and effort.

Further, in order to press the pin 4 of the process unit 3 engaged with the long hole 2 of the side wall 1 with the fixing member 5,
Triangular portion 5a to which spring force of tension coil spring 6 is applied
The vertical component force acting downward by the action of the lower side 5c is used. Therefore, only a small part of the spring force of the tension coil spring 6 is used to press the pin, and many parts are not effectively used. For this reason, in order to securely press the pin 4 with the fixing member 5, the spring force of the tension coil spring 6 must be increased.
Then, a larger force is required when moving the process unit 3 upward.

As described above, in addition to the method of fixing and removing the pins in conjunction with the loading and unloading operations of the process unit, a fixing means for manually fixing and releasing the pins independently of the process unit. And fixing means for fixing and releasing the pin in conjunction with the opening and closing operation of the opening and closing cover provided on the device body have been proposed, but these fixing means require a large force for operation, and the configuration and operation are complicated. There is a problem that is.

Since the present invention has been made based on the above circumstances, an image forming apparatus having a fixing means having a simple structure capable of fixing and removing pins of a process unit with a small force in conjunction with loading and unloading of a process unit. The purpose is to provide.

[0013]

According to the first aspect of the present invention, there is provided an image forming apparatus having a pair of side walls arranged with a gap therebetween, and formed on the pair of side walls along a vertical direction, and the upper end is opened. An apparatus main body having a long hole, a case and a photoconductor supported by the unit, wherein the pair of side walls are moved in and out of a gap between a pair of side walls of the apparatus main body from above and below and moved downward. When inserted into the gap between the pair of side walls, a pin is engaged with the elongated hole of the pair of side walls from above and moves upward to escape from the elongated hole when the pin is removed from the gap between the pair of side walls. Process unit, and fixing means provided on the apparatus main body for fixing the pins of the process unit engaged with the elongated holes of the pair of side walls from above, and the fixing means includes a fixing member and A tension coil spring, wherein the fixing member has a first lever and a second lever, and the first lever has a base end pivotally supported on the side wall by a pivot to be vertically movable, and When the pins of the process unit are engaged with the long holes of the pair of side walls, the pressing position is located across the long holes of the pair of side walls and presses the pins from above, and the upper side of the pair of side walls. Swinging between a release position deviated from the elongated hole, the second lever is supported by the same pivot as the first lever so as to be swingable in the vertical direction, and the first lever is supported by the holding member. A standby position for waiting under the pair of side walls when in the first position;
When the lever is in the release position, it swings integrally with the first lever between an operating position that traverses the slot, and the tension coil spring is connected to the support member located on the side wall and the first lever. And a line connecting the support of the side wall and the pivot axis intersects a direction intersecting a length direction line of the long hole of the pair of side walls, and the first lever is A line connecting the supports is located below the line connecting the support of the side wall and the pivot when in the holding position, and the supports are separated when the first lever is in the release position. A connecting line is located above a line connecting the support of the side wall and the pivot.

According to the present invention, the pins of the process unit are fixed in conjunction with the loading and unloading of the process unit.
The fixing means to be removed has a simple configuration having only the fixing member having the first and second levers and the tension coil spring, but when inserting and removing the process unit, the pin fixes each lever of the fixing member. With the operation, the tension coil spring moves over the pivot point of the fixing member, and the pin can be pressed by operating the fixing member with a small force.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing an image forming apparatus according to the embodiment, FIG. 2 is a side view showing a state where a process unit is loaded in the image forming apparatus, and FIG. 3 is a side view showing a state where the process unit is removed. 4 to 6 are explanatory views showing the operation of the fixing means for fixing the process unit.

FIG. 1 illustrates the entire image forming apparatus. This embodiment is directed to an image forming apparatus used as a laser printer.

In the drawing, reference numeral 51 denotes an apparatus main body of an image forming apparatus;
Is a process unit 52 removably mounted inside the apparatus main body 51. The configuration of the process unit 52 will be described later. Although not shown, the apparatus main body 51 includes a main body case having an open upper surface, and an opening / closing cover for opening and closing the upper surface opening of the main body case. The process unit 52 moves downward from the upper side of the main body case and is provided inside the main body case through the upper surface open portion when the process unit 52 is loaded in a state in which the upper opening portion of the main body case is opened by opening the opening / closing cover. When inserting or removing between the pair of side walls, the member is lifted from the inside of the main body case and moves upward to the upper side of the main body case via the upper surface opening.

Reference numeral 53 denotes a laser optical system for irradiating an image to form an electrostatic latent image on the photosensitive drum 11 constituting the process unit 52, and 54 is provided below the process unit 52 in the apparatus main body 51. This is a recording paper cassette in which recording papers P are stacked and stored. Reference numeral 55 denotes a pickup roller for feeding out the recording paper P stacked on the recording paper cassette 54, reference numeral 56 denotes a feed roller for feeding the recording paper P fed by the pickup roller 55, and reference numeral 57 denotes a process for processing the recording paper P sent by the feed roller 56. A guide that guides toward the unit 52, 58 is a guide 57
A feed roller 59 for feeding between the photosensitive drum 11 of the process unit 52 guided by the printer and a transfer device 19 described later; 59, a heat fixing device provided downstream of the process unit 52 in the recording paper conveyance direction; A discharge roller for discharging the recording paper P that has passed through the heat fixing device 59.

Next, the configuration of the process unit 52 will be described. In the figure, reference numeral 11 denotes a photosensitive drum, which is an example of a photosensitive member, which is rotated in a direction indicated by an arrow by a rotation driving device (not shown). Reference numeral 12 denotes a case having a waste toner accommodating portion 13, which is disposed on the downstream side in the recording paper transport direction with respect to the axis of the photosensitive drum 11, and supports the photosensitive drum 11. The case 12 includes, for example, a contact charging device that is located above the photoconductor drum 11 and contacts and charges the surface of the photoconductor drum 11, that is, a charging brush roller 14 which is an example of a photoconductor charging device. A collection roller 15 for collecting the adhered toner particles and a charging blade 16 for charging the toner particles collected by the collection roller 15 are provided. A collection roller 15 is provided in the case 12.
Is located upstream of the photosensitive member in the rotation direction with respect to the photosensitive drum.
7 are provided.

A developing device 18 is provided on the side facing the case 12 with the photosensitive drum 11 interposed therebetween. The developing device 18 includes a toner hopper 21 for storing the toner T, a supply roller 22, a developing roller 23, a developing blade 24 for pressing the developing roller 23 and a stirrer 25 for stirring the toner T. Roller 23,
The developing blade 24 and the stirrer 25 are
It is supported by. Supply roller 22 and developing roller 2
3 is rotated in the illustrated arrow direction by a rotation driving device (not illustrated).

The photosensitive drum 11, the case 12, the charging brush roller 14, the collection roller 15, and the charging blade 1
A process unit 52 is composed of the discharge lamp 6, the discharge lamp 17, and the developing device 18, and the entire process unit 52 is detachably attached to the apparatus main body 51. Note that a corona transfer device 19, which is an example of the above-described charging device, is provided below the photosensitive drum 11.

A case where an image is recorded on the recording paper P in the image forming apparatus having such a configuration will be described. The recording papers P stacked and accommodated in the cassette 54 are sequentially fed out by a rotating pickup roller 55, then sent out by a feed roller 56, and conveyed along a guide 57. Further, the recording paper P is fed by the rotating feed roller 58 and is supplied to the photosensitive drum 1 of the process unit 52.
And the corona transfer device 19.

The operation of the process unit 52 will be described. The photosensitive drum 11 is rotated. Photoconductor drum 1
The surface 1 is first uniformly charged by a charging brush roller 14, then exposed by an exposure device (not shown) based on image information, the potential of the exposed portion is discharged to form an electrostatic latent image, and then developed. Developed along the electrostatic latent image by the device 18 to form an image with toner particles. In the developing device 18, the supply roller 22 made of foam is used.
The toner T stored in the toner hopper 21 is sent to the surface of the developing roller 13 by the rotation of the developing roller 13, and the toner T passes through the developing blade 14 by the rotation of the developing roller 13. Here, the toner T is negatively charged and spread uniformly on the surface of the developing roller 13 to form a thin layer. The toner image formed on the surface of the photoconductor drum 11 by the corona transfer device 19 is transferred to a recording sheet P passing between the photoconductor drum 11 and the corona transfer device 19. Further, the recording paper P to which the toner image has been transferred passes through the heat fixing device 59, where the toner image is fixed, and is then discharged to the outside of the apparatus main body 51 by the discharge roller 60.

Next, a fixing means for loading and fixing the process unit 52 will be described with reference to FIGS. In this embodiment, two sets of fixing means are arranged side by side at intervals in the length direction of the side wall, and two sets of pins combined with the fixing means are arranged in the process unit. Here, one set will be described.

In the figure, reference numeral 31 denotes a pair of side walls formed integrally with the inside of the main body case of the apparatus main body 51, which has a height at which the process unit 52 can be loaded at a position where the process unit 52 can be loaded. It is formed upright in a flat plate shape. These paired side walls 31
At the upper end of each of the long holes 3 along the vertical direction at the position facing each other
2 are formed. The upper ends of these long holes 32 are the side walls 31.
Is open at the upper edge and closed at the lower end, and has a length such that a pin 33 provided on the process unit 52 can be inserted to the lower end when the process unit 52 is loaded as described later.

In the process unit 52, for example, on both side walls of the case 12, a pair of long holes 32
The pin 33 is provided so as to protrude outward along a direction perpendicular to the surface of the side wall 31.
The pin 33 can be engaged with the elongated hole 32 when the process unit 52 is moved downward and inserted between the pair of side walls 31, and when the process unit 52 is moved downward to a predetermined loading position, the pin 33 reaches the lower end of the elongated hole 32. The position is set to reach and stop. The pins 33 combined with one set of fixing means also serve as a rotating shaft for supporting the photosensitive drum 11 provided in the process unit 52 on the case 12 as shown in FIGS. Stop pins 43 projecting from both side surfaces of the case 12 to the upper edges of the pair of side walls 31 and supporting the process unit 52 in a state where the pins 33 reach the lower ends of the long holes 32 and stop. .

Numeral 34 denotes fixing means provided on the outer side surfaces of the pair of side walls 31, respectively, which presses the pins 33 of the process unit 51 engaged with the elongated holes 32 of the pair of side walls 31 from above. A fixing member 35 provided on the outer surface of the side wall 31 and a tension coil spring 36 provided on the outer surface of the side wall 31 are provided. Further, the fixing member 35 has a V-shape having a first lever 37 and a second lever 38.

The first lever 37 is swingably supported on the side wall 31 by a pivot 39 projecting at right angles to the side wall and projecting horizontally. That is, when the pin 33 of the process unit 52 is engaged with the long hole 32 of the pair of side walls 31, the first lever 37 is positioned so as to cross the long hole 32 of the pair of side walls 31 and moves the pin 33 from above. It swings between a holding position C for holding and a releasing position D which is separated from the elongated hole 32 above the pair of side walls 31.

The second lever 38 is supported by the same pivot 39 as the first lever 37 so as to be vertically swingable. When the first lever 27 is at the holding position C, the pair of side walls 31 is disposed.
Swings integrally with the first lever 37 between a standby position E at which the first lever 37 is in a release position D and an operation position F crossing the long hole 32 of the side wall 31 when the first lever 37 is at the release position D. Things.

The tension coil spring 36 includes a support member 40 located on the side wall 31 and a support member 4 located on the first lever 37.
1, and a line B connecting the support 40 of the side wall 31 and the pivot 39 extends along a direction intersecting the length direction line of the long hole 32 of the pair of side walls 31. Then, the tension coil spring 36
When the first lever 37 is at the holding position C, the line A connecting the supports 40 and 41 is connected to the support 40 of the side wall 31 and the pivot 3.
9, a line A connecting the supports 40 and 41 when the first lever 37 is at the release position D is a line B connecting the support 40 of the side wall 31 and the pivot 39. It is located above.

Thus, loading of the process unit 52,
The pin of the process unit 52 is fixed in conjunction with the removal,
The fixing means 34 to be removed includes the first and second levers 3.
Fixing member 35 having tension members 7 and 38 and tension coil spring 36
This is a simple configuration having only the following. In this embodiment, two sets of fixing means 34 and long holes 32 are provided for each pair of side walls 3131.

The case where the process unit 52 is inserted will be described. As shown in FIG. 3 and FIG.
The first lever 37 in 5 is a long hole 3 of the pair of side walls 31.
The second lever 38 is located at the release position D, which is above the upper end of the second lever 2, and is in the operating position F in which the first lever 37 is inclined and traverses the long hole 32 when the first lever 37 is at the release position C.

When the process unit 52 is moved downward from above and inserted between the pair of side walls 31, the pin 33 is also moved downward integrally and the second lever 38 of the fixing member 35 located at a position overlapping the elongated hole 32. Hit the upper edge. The second lever 38 is pushed by the pin 33 and swings downward about the pivot 39 from the operating position F, and swings to the standby position E where the second lever 38 waits below the pair of side walls 31. The pin 33 moves downward from the upper end opening of the elongated hole 32 in contact with the inside. As shown in FIGS. 2 and 4, the first lever 37 is integrated with the second lever 38 about the pivot 39 and is integrated with the process unit 52.
When the pin 33 is engaged with the long hole 32 of the pair of side walls 31, the pin 33 swings to the holding position A and is located across the long hole 32 of the pair of side walls 31 and is engaged with the long hole 32. Press from above. When the pin 33 hits the lower end of the elongated hole 32 and stops moving downward, the swing of the first lever 37 stops.

On the other hand, when the first lever 37 of the fixing member 35 is in the release position, the tension coil spring 36 moves the line A connecting the supports 40 and 41 to the support 40 of the side wall 31 as shown in FIG. Is located above the line B connecting the When the first lever 37 swings from the release position D to the holding position C, the line A connecting the supports 40 and 41 moves downward as shown in FIGS.
Over the line B connecting the support member 40 and the pivot 39 to the lower side. Thus, the first member 35
Lever 37 is pulled by the tension coil spring 36 and swings quickly downward from the release position D to the holding position C. Therefore, the pin 33 of the process unit 52 does not apply a large force to the second lever 38, and the fixing member 3
5 is lightly swung from the release position D to the holding position C. The tension coil spring 36 is directed downward with respect to the first lever 37 because the line A connecting the supports 40 and 41 is located below the line B connecting the support 40 of the side wall 31 and the pivot 39. The spring 36 acts strongly. For this reason, the first lever 37 of the fixing member 35 strongly presses the pin 33 of the process unit 52 from above, and presses the pin 33 against the lower end of the long hole 32 of the side wall 31 to securely fix it.

The case where the process unit 52 is removed will be described. When the process unit 52 is moved upward from between the side walls 31 as shown in FIG.
The first lever 37 of the fixing member 35 pressing the third lever 37
Is pressed by the pin 33 and the holding position A about the pivot 39.
Swings upwards from As shown in FIG. 6, the pin 33 of the process unit 52 rises along the length direction of the long hole 32, pulls out from the upper end opening, and pulls out above the side wall 31. First
The lever 37 is separated from the elongated hole 32 and swings to the release position D on the upper side of the side wall 31. The second lever 38 swings upward from the standby position E about the pivot 39 integrally with the first lever 37 and moves to the operation position F crossing the length direction of the long hole 32.

On the other hand, as shown in FIG. 4, when the first lever 37 of the fixing member 35 is at the holding position C, a line A connecting the supports 40 and 41 is And the pivot 39 are located below the line B. As shown in FIG. 5, when the first lever swings from the holding position C to the release position D, the line A connecting the supports 40 and 41 moves downward, and the support 40 of the side wall 31 and the pivot 3
9 and moves to the upper side thereof as shown in FIG. As a result, the second lever 38 of the fixing member 35 is pulled by the tension coil spring 36 and rapidly swings upward from the standby position E to the operation position F. For this reason, the pin 33 of the process unit 52 is
The first lever and the second lever 38 of the fixing member 35 swing lightly without applying a large force to 8. In addition, as shown in FIG.
The swing of the fixing member 35 is stopped by colliding with the stopper provided in 1.

Thus, loading of the process unit 52,
The fixing means 34 for fixing and removing the pin 33 of the process unit 52 in conjunction with the removal includes only the fixing member 35 having the first and second levers 37 and 38 and the tension coil spring 36 as described above. The pin 33 operates the levers 37 and 38 of the fixing member 35 when the process unit 52 is inserted and removed, and the tension coil spring 36 moves over the pivot point of the fixing member 35 with the simple structure of FIG. Operate the fixing member 35 with a small force.
Can be operated to press the pin 33.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications.

[0039]

According to the image forming apparatus of the present invention, the fixing means for fixing and removing the pins of the process unit in conjunction with the loading and unloading of the process unit is a fixing member having first and second levers. The pin operates each lever of the fixed member when loading and unloading the process unit, and the tension coil spring moves over the pivot point of the fixed member. By operating, the pin can be pressed by operating the fixing member with a small force.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a loaded state of a process unit in the image forming apparatus of the embodiment.

FIG. 3 is a side view illustrating a detached state of the process unit in the image forming apparatus according to the embodiment.

FIG. 4 is a diagram showing an operation of a fixing unit for fixing the process unit in the image forming apparatus according to the embodiment.

FIG. 5 is a diagram showing an operation of a fixing unit for fixing the process unit in the image forming apparatus according to the embodiment.

FIG. 6 is a diagram showing an operation of a fixing unit for fixing the process unit in the image forming apparatus according to the embodiment.

FIG. 7 is a view showing a fixing unit for fixing a process unit in a conventional mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Photoreceptor drum 12 ... Case, 31 ... Side wall, 32 ... Long hole, 34 ... Fixing means, 35 ... Fixing member, 36 ... Spring, 37 ... First lever, 38 ... Second lever, 39 ... Axis, 51: apparatus main body, 52: process unit, A: line B: spring action line.

Claims (1)

[Claims] An apparatus main body having a pair of side walls arranged with a gap therebetween, a long hole formed in each of the pair of side walls along a vertical direction, and having an open upper end, a case, and a case supported by the case. When the photosensitive drum is inserted into and removed from the gap between the pair of side walls of the apparatus main body from above and below, and moved downward and inserted into the gap between the pair of side walls, the length of the pair of side walls is increased. A process unit, which is engaged with the hole from the upper side and moves upward and moves out of the gap between the pair of side walls when the pin escapes from the long hole, is provided in the case, Fixing means provided on the apparatus main body for fixing the pins of the process unit engaged from above, the fixing means comprising a fixing member and a tension coil spring; And a second lever, wherein the first lever has a base end pivotally supported on the side wall by a pivot so as to be vertically swingable, and a pin of the process unit has a long hole in the pair of side walls. Swings between a holding position for traversing the long hole of the pair of side walls and pressing the pin from above when engaged with the pair, and a releasing position for disengaging from the long hole above the pair of side walls. The second lever is swingably supported in the vertical direction by the same pivot as the first lever, and waits below the pair of side walls when the first lever is at the holding position. The first position between the standby position and the operating position traversing the slot when the first lever is in the release position.
The tension coil spring is supported by a support positioned on the side wall and a support positioned on the first lever, and a line connecting the support on the side wall and the pivot axis is formed. A line connecting the supports when the first lever is at the holding position extends along a direction intersecting a longitudinal direction line of the long holes of the pair of side walls and connects the support of the side walls and the pivot. A line connecting the supports when the first lever is in the release position, and a line connecting the supports when the first lever is at the release position is positioned above a line connecting the support on the side wall and the pivot. Image forming apparatus.