JP2001134088A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of positioning a developing unit and a photoreceptor unit with much higher positioning accuracy. SOLUTION: A developing unit 11 holding a specified number of developing devices is supported to be rocked around a rocking fulcrum shaft 19 in a holding unit 12 provided to be drawn out/inserted into the front direction of a main body. Developing unit right-and-left and up-and-down directions positioning parts 11x and 11y accurately positioned and provided with respect to the shaft 19 in the unit 11 abut on photoreceptor unit right-and-left and up-and-down directions positioning parts 5x and 5y accurately positioned and provided in the photoreceptor unit 5 accurately positioned and fixed in the main body, whereby the unit 11 and the unit 5 are more accurately and more easily positioned in up-and-down and right-and-left directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller having a thin toner layer formed on a surface thereof at a certain distance from a photoreceptor at the time of non-development. It belongs to the technical field of an image forming apparatus in which a developing device is controlled so that a toner image is formed on a photoconductor in close proximity.In particular, a developing unit that holds a developing device and a photoconductor unit that holds a photoconductor are included. It belongs to the technical field of an image forming apparatus which is provided so as to be individually positioned.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrostatic copying machine or a printer, a thin toner layer is formed on the surface of a developing roller held by a developing device, and the developing roller is used as a photosensitive member when not developing. 2. Description of the Related Art There is known an image forming apparatus which forms a toner image on a photosensitive member by setting the developing position to a non-developing position separated from the photosensitive member by a certain distance or more and setting the developing position to be in contact with or close to the photosensitive member during development. ing. In such an image forming apparatus, the developing unit is slidably or rotatably held in a developing unit which is a housing, and the above-described separation / contact operation of the developing roller with respect to the photoconductor is performed using a power transmission control mechanism such as a clutch. ing. When performing a predetermined operation on the developing device such as replacement of the developing device or replacement of the toner cartridge held in the developing device, the developing unit holding the developing device is pulled out of the main body of the image forming apparatus. Working.

[0003]

In recent years, there has been a strong demand for an image forming apparatus to have a high speed image formation.
One of the ways to speed up image formation is, for example, to increase the image formation speed. For that purpose, it is necessary to reduce the time required for switching the developing roller between the non-development position and the development position. Therefore, the separation distance between the developing roller and the photoconductor at the non-development position of the developing roller is set to a minimum necessary distance that the toner on the surface of the developing roller is not attracted by the electric field applied to the surface of the photoconductor. are doing. However, if the separation distance between the developing roller and the photoconductor is set to a minimum as described above, when the developing unit is pulled out of the main body, the developing roller interferes with the photoconductor unit, and the developing unit is pulled out of the main body. In some cases, it is not possible.

Therefore, the developing unit is held by the holding unit so as to be swingable (rotatable) about a swing fulcrum shaft, and the developing unit is swung to bring the developing roller sufficiently away from the photosensitive member. It is conceivable that the holding unit is pulled out of the main body. However, when the developing unit is swung in this manner, it is difficult to position the developing unit with respect to the photoconductor, and the positioning accuracy between the photoconductor and the developing unit is reduced, and it is difficult to perform stable and good development. Become. In order to improve the positioning accuracy between the photoconductor and the developing unit, the accuracy of each component such as the developing device and the photoconductor is made as high as possible, and the mounting of the components to the main body frame such as the photoconductor unit, the developing unit and the holding unit is performed. It is conceivable to make the accuracy as high as possible.

For this purpose, (1) the developing roller is positioned on the developing device with a predetermined positioning accuracy, (2) the developing device is positioned on the developing unit with a predetermined positioning accuracy, and (3) the developing unit is mounted on the holding unit with a predetermined positioning accuracy. (4) Positioning the holding unit on the main body of the device with a predetermined positioning accuracy, (5) Positioning the photoconductor on the photoconductor unit with a predetermined positioning accuracy, (6) Mounting the photoconductor unit on the device It is necessary to position the main body with a predetermined positioning accuracy.

However, when positioning is performed in this manner, there are a wide variety of positioning members, and the accuracy of these positioning members and the mounting accuracy of the positioning members vary.
Since the developing unit and the photoconductor unit are individually positioned, it is extremely difficult to position the developing roller and the photoconductor with high positioning accuracy.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image forming apparatus capable of positioning a developing unit and a photoreceptor unit with higher positioning accuracy. It is to be.

[0008]

In order to solve this problem, the invention according to claim 1 is directed to a method of determining a position of a main body between a mounting position which is positioned and mounted in the main body and a pulling position which is pulled out of the main body. A holding unit provided so as to be able to be pulled out and inserted in the front-rear direction of the main body, a developing unit positioned so as to be swingable and held by the holding unit, and holding a predetermined number of developing units; and a positioning unit attached to the main body. And a photoreceptor unit for holding a photoreceptor, wherein a photoreceptor unit side positioning portion is positioned and provided on the photoreceptor unit, and a developing unit side positioning portion is positioned and provided on the developing unit. And the developing unit swings,
The positioning between the developing unit and the photoconductor unit is performed by bringing the positioning unit on the developing unit side into contact with the positioning unit on the photoconductor unit side.

Further, in the invention according to claim 2, the photoconductor unit side positioning section and the photoconductor unit side left / right positioning section for positioning the main body left and right and the photoconductor unit for vertical positioning of the main body. And a developing unit side positioning portion that abuts the photoconductor unit side left / right positioning portion to perform the main body left / right positioning of the developing unit and the photoconductor unit. A developing unit side left / right positioning unit; and a developing unit side vertical positioning unit that abuts on the photoconductor unit side vertical positioning unit and performs positioning of the developing unit and the photoconductor unit in the main body vertical direction. It is characterized by:

Further, according to a third aspect of the present invention, a predetermined play is provided between the holding unit and the developing unit at a swinging fulcrum of the developing unit. The contact of the left-right positioning portion with the left-right positioning portion on the photoconductor unit side and the contact of the vertical positioning portion on the developing unit side with the vertical positioning portion on the photoconductor unit are performed simultaneously or almost simultaneously. It is characterized by being.
Further, the invention according to claim 4 is provided with a developing unit swing lock means for holding the developing unit in a proper position when positioning the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body. The unit is held at a regular position by the developing unit swing lock means and is positioned relative to the photoreceptor unit in the vertical and horizontal directions of the main body.

Further, according to a fifth aspect of the present invention, the developing unit swing lock means is provided in the developing unit so as to be positioned with respect to the developing unit side left / right positioning unit and the developing unit side vertical positioning unit. The positioning member and the pivoting fulcrum pin, which is provided to be positioned on the holding unit, is rotatably provided, and rotates around the oscillating fulcrum pin in conjunction with the swinging of the developing unit. A swing lock member that holds the developing unit in a proper position by engaging with the positioning member when positioning the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body; When mounted in the mounting position, the swing fulcrum pin,
The holding unit is positioned with respect to the photoconductor unit by being fitted into a positioning hole provided in the main body so as to be positioned with respect to a mounting position of the photoconductor unit. The invention of claim 6 is
A swing fulcrum pin of the swing lock member is provided on one side before and after the holding unit, and the positioning hole is provided with the swing fulcrum pin of the holding unit before and after the main body. It is characterized in that it is provided on the same side as the side where it is located.

Further, according to a seventh aspect of the present invention, the developing unit swing lock means is provided on the developing unit so as to be positioned with respect to the developing unit side left / right positioning unit and the developing unit side vertical positioning unit. The positioning member, and is provided rotatably on a swing fulcrum shaft provided to be positioned in the holding unit, and rotates around the swing fulcrum shaft in conjunction with the swing of the developing unit, A swing lock member that holds the developing unit in a proper position by engaging with the positioning member when positioning the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body; When mounted at the mounting position, the swing fulcrum shaft is positioned on the main body so as to be positioned with respect to the mounting position of the photoconductor unit. By being fitted into the hole, and wherein the holding unit is positioned with respect to the photosensitive member unit. Further, in the invention according to claim 8, the positioning hole is provided on one of the front and rear sides of the main body, and the pivot shaft of the rocking lock member is provided with the positioning hole of the holding unit. It is characterized in that the end on the same side as the side on which it is set is fitted into this positioning hole.

Further, according to a ninth aspect of the present invention, the swing lock member comprises a swing lock lever, and the swing lock lever is connected to a swing fulcrum shaft of the developing unit via a predetermined number of link levers. Holding the developing unit in a proper position by engaging with the positioning member when the developing unit and the photoreceptor unit are positioned in the vertical and horizontal directions of the main body by interlocking with the swing of the developing unit. It is characterized by being adapted to.

[0014]

In the image forming apparatus according to the present invention, the developing unit is directly positioned on the photosensitive unit without the intervention of the main body, so that the positioning between the developing unit and the photosensitive unit can be performed with high accuracy. You will be

In particular, in the second aspect of the present invention, the developing unit is directly positioned in the upper, lower, left and right directions of the main body without interposing the main body on the photoreceptor unit. Positioning is performed with high accuracy. According to the third aspect of the present invention, since the developing unit is directly positioned on the photoreceptor unit simultaneously in both the upper, lower, left and right directions, the positioning of the developing unit and the photoreceptor unit in the upper, lower, left and right directions can be performed with higher accuracy. You will be Furthermore, in the invention of claim 4, since the developing unit is held in the proper position and positioned in the vertical and horizontal directions of the main body with respect to the photoreceptor unit, the positioning of the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body can be performed. It will be performed with even higher precision.

Further, according to the fifth aspect of the present invention, a swing fulcrum pin of a swing lock member, which is positioned and provided with high precision in the holding unit, is fitted into a positioning hole formed in the main body with high precision. Therefore, the holding unit is accurately positioned with respect to the photoconductor unit. As a result, the developing unit is positioned with higher accuracy with respect to the photoconductor unit. Further, in the invention according to claim 6, the swing fulcrum pins of the swing lock member provided on one side of the front and rear of the holding unit are the front and rear sides of the main body, on the side where the swing fulcrum pins of the holding unit are provided. Is positioned on the same side with high precision with respect to the mounting position of the photosensitive unit, and is fitted into a positioning hole drilled to position one side before and after the holding unit, and the other side before and after the holding unit. The side is freed. Accordingly, when the developing rollers of the respective developing units are set to the developing positions, the positioning is performed so as to follow the photosensitive member without affecting the positional accuracy in the front-rear direction of the main body. By such a combination of the positioning of the holding unit before and after, each developing roller is positioned with high precision in parallel with the photosensitive member.

Further, in the invention according to claim 7, the swing fulcrum shaft of the swing lock member, which is positioned and provided with high precision in the holding unit, is fitted into the positioning hole formed in the main body with high precision. Therefore, the holding unit is accurately positioned with respect to the photoconductor unit. As a result, the developing unit is positioned with higher accuracy with respect to the photoconductor unit. Further, in the invention according to claim 8, the positioning of the swinging fulcrum shaft of the swinging lock member is carried out in a positioning hole formed in one of the front and rear sides of the main body, which is positioned with high precision with respect to the mounting position of the photosensitive unit. The end on the same side as the side on which the positioning holes are provided is fitted to position one of the front and rear sides of the holding unit, and the other side of the front and back of the holding unit is free. Thus, when the developing rollers of each developing device are set to the developing position without affecting the position accuracy in the front-rear direction of the main body,
It is positioned so as to follow the photoconductor. By such a combination of the positioning of the holding unit before and after, each developing roller is positioned with high precision in parallel with the photosensitive member.

Further, according to the ninth aspect of the present invention, the swing lock member comprises a swing lock lever.
The swing lock lever rotates in association with the swing of the developing unit via a predetermined number of link levers. In this case, the structure is simplified because a predetermined number of levers are simply connected in a link shape.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing an entire full-color image forming apparatus to which an example of an embodiment of the image forming apparatus of the present invention is applied, and FIG.
It is sectional drawing which follows a line.

As shown in FIGS. 1 and 2, a full-color image forming apparatus 1 of this embodiment is positioned and fixed on a main body 2 of the image forming apparatus 1 and has a photosensitive member (hereinafter referred to as an OPC).
An optical scanning system for exposing an image to be formed to a photoconductor unit 5 having a photoconductor cleaner 3 and an OPC 3 charged by a charging roller (not shown) disposed in the photoconductor unit 5. Exposure unit (hereinafter LSU)
6), a developing unit 11 for holding yellow, magenta, cyan, and black developing units 7, 8, 9, 10; and a developing unit 11 positioned on the main body 2 and in front of the main body 2 (see FIG. 1). And a developing unit 7, which is attached to the developing unit 11 so as to be swingable, and a developing unit 7, 8, 9, 10
Intermediate transfer body 13 on which toner image on PC 3 is intermediately transferred
A transfer unit 14 for transferring an intermediate transfer image on the intermediate transfer body 13 to transfer paper, a fixing unit 15 for fixing a transfer image transferred to the transfer paper, and a transfer unit 14 which is set in the main body 2 and accommodates the transfer paper. A paper feed cassette 16, a manual paper feed tray 17 that is provided on the front side of the main body 2 (that is, the right side in FIG. 1) and stores transfer paper when the transfer paper is supplied manually, and a paper feed tray 17 that is provided above the main body 2 And a discharge tray 18 for storing transfer paper on which an image is formed.

The OPC 3 is positioned with high precision between the front and rear frames 5a and 5b of the photoconductor unit 5, and is rotatably provided in a counterclockwise direction in FIG. On the surface of the OPC 3, a latent image of an image to be formed is formed by the LSU 6, and yellow, magenta, and magenta are respectively formed by the developing units 7, 8, 9, and 10.
Cyan and black toner images are formed. The photoconductor cleaner 4 removes and stores the residual toner on the OPC 3 after the intermediate transfer. Further, the photosensitive member unit 5 includes a positioning pin 5c.
, Is positioned and fixed to the front frame 2a of the main body 2 with high precision, and is positioned and fixed to the rear frame 2b of the main body 2 with high precision by the positioning pins 5d and 5e. Therefore, the OPC 3 is positioned with high precision with respect to the main body 2.

The yellow, magenta, cyan, and black developing units 7, 8, 9, and 10 are arranged along the outer periphery of the OPC 3 and in order from the rotation upstream side of the OPC 3.
The order in which the developing units 7, 8, 9, and 10 are arranged is not limited to the order described above, but may be set arbitrarily. Also, in the following description, for convenience of explanation, the order of the aforementioned colors, that is,
It is assumed that the developing units 7, 8, 9, and 10 are arranged in the order of yellow, magenta, cyan, and black. Each of the developing units 7, 8, 9, and 10 is positioned with high precision in the developing unit 11 and is slidably or rotatably held. Each of these developing units 7, 8, 9, 10
Each is provided to be detachable from the OPC3, and
The developing rollers 7a, 8a, 9a, and 10a that transport toner for developing the latent image on the OPC 3 to the OPC 3 are provided. FIG. 1 shows the developing rollers 7a, 8 of the respective developing units 7, 8, 9, 10.
a, 9a, and 10a are shown in contact with the OPC 3, but these developing rollers 7a, 8a, 9a, 1
0a is held at a non-development position separated from the OPC 3 at the time of non-development, and at an appropriate order during development.
OP is set at the developing position in contact with or close to C3,
The latent image on C3 is developed.

Each developing roller 7a, 8a,
The contact or proximity operation and separation operation of 9a and 10a are as follows.
Each developing unit 7, 8, 9, 10 is connected to a mechanism such as a clutch (not shown).
Is performed by a driving means (not shown) such as a motor. In this case, the separation distance from the OPC 3 to the non-development position of each of the developing rollers 7a, 8a, 9a, and 10a at the time of non-development is determined by each developing roller in order to correspond to the reduction of the switching time for increasing the printing speed. 7a, 8a, 9a, 10a
The distance is set to a necessary minimum distance such that the toner on the surface of the OPC 3 is not attracted by the electric field applied to the surface of the OPC 3.

As shown in FIGS. 2 and 3, the developing unit 11 includes front and rear frames 11a and 11b and upper and lower stays 11a.
From c and 11d, a casing having a predetermined strength is formed. The developing unit 11 has an upper end and a side end on the side of the yellow developing device 7 that are the holding unit 12.
In addition, it is held by a swing fulcrum shaft 19 so as to be able to swing (rotate) around the swing fulcrum shaft 19. In this case, the swing fulcrum shaft 19 is connected to the front and rear frames 12a, 1 of the holding unit 12.
2b, these frames 12a, 12b are rotatably supported through the frames 12a, 12b, and the front and rear frames 11a, 11b of the developing unit 11 have through holes each having a diameter slightly larger than the diameter of the pivot shaft 19. 11e, 11f
Are formed, and penetrate through these through holes 11e and 11f in a state where the swing fulcrum shaft 19 is loosely fitted. Therefore, the developing unit 11 can swing independently of the rotation of the swing fulcrum shaft 19. By the swing of the developing unit 11, each of the developing rollers 7a, 8a, 9a, and 10a is set to be in contact with or close to the OPC 3 so as to be capable of developing, and any of the developing rollers 7a, 8a, 9a, 1
0a is also set to be sufficiently evacuable from the OPC3.

Similarly to the developing unit 11, the holding unit 12 has front and rear frames 12a and 12b and upper and lower stays 12c and 12c.
12d, it is formed as a housing having a predetermined strength. As shown in FIG. 3, the holding unit 12 is guided by a pair of guide rails 20 and 21 provided between the holding unit 12 and the main body 2 to move the developing rollers 7 a, 8 a, 9 a and 10 a from the OPC 3. It can be inserted into the main body 2 and can be pulled out from the main body 2 in a state of being sufficiently retracted.

The one guide rail 20 is disposed between the side end of the holding unit 12 on the fulcrum shaft 19 side and the main body 2, and the other guide rail 20 is provided for the black developing device of the holding unit 12. It is arranged between the lower end on the 10 side and the main body 2. Each of the pair of guide rails 20 and 21 has the same configuration, respectively, as shown in FIG.
As shown in (b), a holding unit side rail 22 fixed to the holding unit 12 side, a main body side rail 23 fixed to the main body 2 side, and a middle provided between these two rails 22, 23. It consists of a rail 24.

The holding unit side rail 22 has both side ends 22a and 22b bent downward at substantially right angles to have a substantially U-shaped cross section, and both side ends 22a and 22b are respectively inwardly circular. It is curved in an arc. Also, the main body side rail 23 has both side end portions 23.
a, 23b are bent upward at substantially right angles to form a substantially U-shaped cross section, and both side ends 23a, 23b are each curved outward in an arc shape. Further, the intermediate rail 24 is formed in a substantially U-shaped cross-section by bending both side ends 24a and 24b upward at substantially right angles in the same manner as the main body side rail 23, but these side ends 24a and 24b are formed. Are further bent by 180 ° to form inner and outer ends 24a ₁ , 24a ₂ ; 24b ₁ ,
24b ₂ is formed as a double layer. Inside end 2
4a ₁ and 24b ₁ are each curved outwardly in an arc shape, and the outer side ends 24a ₂ and 24b ₂ are each curved inwardly in an arc shape.

Then, the holding unit side rail 22 is inserted into the intermediate rail 24 and the arcuate curved portions of both side ends 22a and 22b of the holding unit side rail 22 and both inner side ends 24a ₁ and 24b ₁ of the intermediate rail 24 are provided. The arc-shaped curved portions are disposed so as to face each other with a predetermined gap, and the intermediate rail 24 is provided in the main body-side rail 23 with the arc-shaped curved portions of both side ends 23 a and 23 b of the main body-side rail 23. The portion and the arc-shaped curved portions of both outer end portions 24a ₂ and 24b ₂ of the intermediate rail 24 are disposed so as to face each other with a predetermined gap.

Further, a substantially U-shaped first wire 25 is disposed on the upper surface of the intermediate rail 24 in a direction orthogonal to the longitudinal direction of the intermediate rail 24. The first wire 25 has a central portion 25c fixed to the upper surface of the central portion 24c of the intermediate rail 24, and has both end portions 25a, 25b.
Are both end portions 22 of the holding unit side rail 22.
a, which is to be located in the center of the gap between the arc-shaped curved portion and two inner end 24a _1, 24b arc-shaped curved portion of the _first intermediate rail 24 of 22b. Balls 26 and 27 are supported at both end portions 25a and 25b of the first wire rod 25 so as to be rotatable around both end portions 25a and 25b, respectively. These balls 26, 27 are provided at both ends 22a, 22.
b, the curved surface and both inner side ends 24a ₁ , 24b ₁
And rolls between these curved surfaces in contact with the curved surfaces. A set of first wires 25 and balls 26 and 27 is provided on a predetermined number of intermediate rails 24 at predetermined intervals along the longitudinal direction.

Similarly, on the lower surface of the intermediate rail 24,
A substantially U-shaped second wire 28 is arranged in a direction orthogonal to the longitudinal direction of the intermediate rail 24. This second wire rod 28
The center part 28c is the center part 24c of the intermediate rail 24.
And is fixed to the lower surface of the
a and 28b are both end portions 23 of the main body side rail 23, respectively.
a, which is to be located in the center of the gap between the arc-shaped curved portion and the arcuate curved portions of the outer side end portion 24a _2, 24b ₂ of the intermediate rail 24 for 23b. Then, the second wire rod 28
Balls 29, 3 are attached to both side ends 28a, 28b, respectively.
0 is supported so as to be rotatable around both side ends 28a and 28b. These balls 29 and 30 are
a, 28b and both outer side end portions 24a ₂ ,
So that the roll between these curved surfaces in contact with the arcuate curved surface of 24b _2. A set of the second wire rod 28 and the balls 29, 30 is provided on the intermediate rails 24 of a predetermined number of sets at predetermined intervals along the longitudinal direction.

The holding unit side rail 22, main body side rail 23 and intermediate rail 24 are supported vertically and horizontally in FIG. 4 (b) by the balls 26 and 27 inside the intermediate rail 24. In addition, the intermediate rail 24 is incorporated so as to be relatively movable in the longitudinal direction, and the intermediate rail 24 is
In FIG. 4B, the balls 29 and 30 are supported by the balls 29 and 30 in the up, down, left and right directions, and are incorporated so as to be relatively movable in the longitudinal direction with respect to the main body side rail 23.

In order to stop and position the holding unit 12 when the holding unit 12 is mounted on the main body 2, one end of the intermediate rail 24 is brought into contact with a stopper 31 provided at one end of the main body side rail 23. 4, the direction in which the holding unit 12 is pushed into the main body 2,
2A, the downward movement of the intermediate rail 24 is restricted, and one end of the holding unit side rail 22 abuts against a stopper 32 provided at one end of the intermediate rail 24, whereby the main body of the holding unit 12 is formed. The movement of the holding unit side rail 22 in the pushing direction toward the second unit 2 is restricted. Further, in order to stop and position the holding unit 12 when the holding unit 12 is pulled out from the main body 2 to the maximum, the intermediate rail 24 is positioned at a position shown in FIG. 4 (a), the holding unit side rail 22 is positioned relative to the intermediate rail 24 in the position shown in FIG. 4 (a). Further, relative movement in the pull-out direction is prevented.
In this manner, the holding unit side rail 22, the main body side rail 23, and the intermediate rail 24 are positioned at the maximum pulled-out position shown in FIG. It is telescopically expandable and contractible between positions abutting 31 and 32.

Further, as shown in FIG.
X of the developing unit 11 with respect to the photoconductor unit 5
3, a developing unit X-direction positioning portion 11 x for positioning in the left and right directions in FIG.
3, that is, a developing unit Y-direction positioning portion 11y for positioning in the vertical direction in FIG. Although these positioning portions 11x and 11y are formed by protrusions in the illustrated example, they can be formed by other appropriate means such as a surface.

On the other hand, the photoconductor unit 5 also has a photoconductor unit X-direction positioning portion 5x which can position the developing unit X-direction positioning portion 11x in contact with the developing unit 11 in the X direction. A photoconductor unit Y-direction positioning portion 5y is provided, which is capable of abutting the developing unit Y-direction positioning portion 11y, by which the photoconductor unit 5 is positioned in the Y direction by abutting the developing unit Y-direction positioning portion 11y. . Although these positioning portions 5x and 5y are formed by surfaces in the illustrated example, they can be formed by other appropriate means such as projections similar to the positioning of the developing unit 11.

Then, as shown in FIG. 3, the developing unit 11 swings about the swing fulcrum shaft 19, and the developing unit X and the Y-direction positioning portions 11x and 11y are respectively moved to the photosensitive unit X and the Y-direction. By contacting the positioning portions 5x and 5y, the photosensitive unit 5 and the developing unit 11
The positioning in the X and Y directions is directly performed with high precision without the intervention of the main body 2. As described above, in a state where the developing unit 11 is positioned in the X and Y directions with respect to the photoconductor unit 5, each of the developing units 7, 8,
The developing rollers 9a, 8a, 9a, 10a 9 and 10 are set with higher precision at the developing positions in contact with or close to the OPC 3, respectively. As described above, the developing unit X and the Y-direction positioning portions 11x and 11y constitute a first positioning portion provided in the developing unit 11.

When positioning the developing unit 11 in the X and Y directions by swinging about the swing fulcrum shaft 19 as described above, the positioning of the developing unit 11 in the X and Y directions with respect to the swing center of the developing unit 11 is performed. Part 11x,
11y, the developing unit X
And the Y-direction positioning portions 11x and 11y are difficult to simultaneously contact the photoconductor unit X and the Y-direction positioning portions 5x and 5y, respectively, and only one of these developing units X and the Y-direction positioning portions 11x and 11y is provided. There is a possibility that the corresponding photoconductor unit X and the Y-direction positioning portions 5x and 5y do not come into contact with each other and the other positioning cannot be performed. For example, when the height from the swing center of the developing unit 11 to the developing unit Y-direction positioning portion 11y is increased due to the variation, the developing unit Y-direction positioning portion 11y contacts the photoconductor unit Y-direction positioning portion 5y. The developing unit 1
1 is held in a state of being lifted upward, and is not held in the original normal state (horizontal state). For this reason,
The developing unit X-direction positioning portion 11x does not come into contact with the photoconductor unit X-direction positioning portion 5x, and the X-direction positioning of the photoconductor unit 5 and the developing unit 11 cannot be performed.

Therefore, in the image forming apparatus 1 of this embodiment, as described above, the developing unit 11
The diameters of the through holes 11e and 11f are set slightly larger than the diameter of the swing fulcrum shaft 19, and the swing fulcrum shaft 19 is
By loosely fitting e and 11f, a predetermined play is provided between the swing fulcrum shaft 19 and the developing unit 11. With this play, the variation in the positions of the developing unit X and the Y-direction positioning portions 11x and 11y with respect to the swing fulcrum of the developing unit 11 is absorbed, so that the developing unit X and the Y-direction positioning portions 11x and 11y respectively become photosensitive member units. It is possible to simultaneously contact the X and Y direction positioning portions 5x and 5y.

However, if there is a backlash between the pivot shaft 19 and the developing unit 11 as described above, when there is no such variation in the positioning portions 11x and 11y of the developing unit 11, or when the variation is large or small. In some cases, as shown in FIG. 5, the developing unit 11 slides down below the normal horizontal state by the difference between the diameter of the pivot 19 and the diameter of the through holes 11e and 11f of the developing unit 11. It is conceivable that the developing unit 11 may be held in a state in which the upper surfaces of the through holes 11 e and 11 f are in one-side contact with the upper surface of the pivot shaft 19. In FIG. 5, reference numerals in parentheses indicate, for convenience, members arranged on the rear side (the back side of the drawing in FIG. 1) of the image forming apparatus 1 in correspondence with members arranged on the front side. .

Therefore, in the image forming apparatus 1 of this example, the developing unit 11 and the developing unit X and the Y-direction positioning units 11x and 11y are further moved to the photosensitive unit X and the Y-direction positioning units 5x and 5y, respectively. To be able to contact at the same time. That is,
As shown in FIGS. 2 and 5, a pair of first swing link levers 33 and 34 are provided between the front frame 11a of the developing unit 11 and the front frame 12a of the holding unit 12 and outside the rear frame 12b of the holding unit 12, respectively. , And one end thereof is connected and fixed to a swing fulcrum shaft 19 so as to be rotatable integrally with the swing fulcrum shaft 19.
One end portions of second swing link levers 35 and 36 are connected to the other end portions of the first swing link levers 33 and 34, respectively, so as to be relatively rotatable. One ends of swing lock levers 37, 38 are connected to the other ends of 35, 36, respectively, so as to be relatively rotatable. The swing lock levers 37 and 38 are formed in the same shape as each other, and the front and rear frames 1 of the swing unit 12 are
The swing fulcrum pins 39, 40 provided in 2a, 12b with their relative positions to the swing fulcrum shaft 19 being held with high precision,
Each is held swingably without backlash. That is, the swing fulcrums of the swing lock levers 37 and 38 are positioned with high precision with respect to the swing fulcrum shaft 19. The first and second swing link levers 33, 34; 35, 36 are interlocked with the rotation of the swing fulcrum shaft 19, and the respective swing lock levers 37, 38 are centered on the swing fulcrum pins 39, 40. And swing and rotate.

The swing fulcrum pin 40 provided on the rear frame 12b of the holding unit 12 has an extension 40a formed with high precision at the center thereof. When set to the mounting position, as shown in FIG. 2, the rear frame 2b of the main body 2 on the same side as the swing fulcrum pin 40 having the extension 40a.
In addition, the positioning pins 2d and 5e of the photoconductor unit 5 are fitted into the positioning holes 2c formed with high precision without rattling.

In addition, instead of the swing fulcrum pins 39 and 40,
Although not shown, one swing fulcrum shaft may be bridged between the front and rear frames 12a and 12b of the swing unit 12 and similarly positioned with high accuracy with respect to the swing fulcrum shaft 19. In this case, the end of the pivot shaft on the side where the positioning hole 2c is provided is fitted into the positioning hole 2c without play.

The other end portions of the swing lock levers 37 and 38 are engaged with positioning pins 41 and 42 of a second positioning portion, which will be described later, so that the developing unit 11 is brought into a proper position. The guide surfaces 37b, 38 for guiding the developing unit normal position setting portions 37a, 38a and the positioning pins 41, 42 of the arcuate concave portions set and held in the developing unit normal position setting portions 37a, 38a.
b is formed. Developing unit regular position setting unit 37
Both a and 38a are positioned with high precision with respect to their pivot points. Positioning pins 41, 42 are held on the front and rear frames 11a, 11b of the developing unit 11 with high precision relative to the developing unit X and the Y-direction positioning units 11x, 11y as the first positioning unit.
Is provided. These positioning pins 41, 42
Constitutes a second positioning section provided in the developing unit 11 for positioning the developing unit 11 and the photoconductor unit 5 with high accuracy.

As shown in FIG. 6, an operation lever 43 is provided on the front frame 12a of the holding unit
4 rotatably supported. The rotation fulcrum pin 44 is fitted to the operation lever 43 and can rotate integrally with the operation lever 43. The rotation fulcrum pin 44
Is fitted with an operation drive gear 45, and this rotation fulcrum pin 4
The swing fulcrum shaft 19 is provided with a swing fulcrum shaft driving gear 46 so as to be rotatable integrally with the swing fulcrum shaft 19. I have. These two drive gears 45 are connected to the front frame 2.
a through an intermediate gear 47 rotatably supported. Thus, when the operation lever 43 is rotated, the rotation of the operation lever 43 is transmitted to the swing fulcrum shaft 19 via the rotation fulcrum pin 44, the operation drive gear 45, the intermediate gear 47, and the swing fulcrum shaft drive gear 46. And the swing fulcrum shaft 19 rotates. Accordingly, the rotation of the operation lever 43 causes the pivot shaft 19 to rotate, and furthermore, the first and second pivot link levers 33, 34;
38 pivotally rotates about pivot pins 39 and 40.

Further, a cam 48 is located on the rotation fulcrum pin 44 on the front frame 12a side of the operation drive gear 45 so as to be able to rotate integrally with the rotation fulcrum pin 44, ie, to be able to rotate integrally with the rotation of the operation lever 43. Is provided. The cam 48 has a convex control surface 48 a for controlling the cam control pin 50, which will be described later, by the rotation of the operation lever 43 to control the swing of the developing unit 11, and the developing unit 1.
And a lock portion 48b formed of an arcuate concave portion for holding the photoreceptor 1 at a position separated from the photoreceptor unit 5. A developing unit swing drive lever 49 is provided between the swing support shaft 19 and the positioning pin 41 so as to be rotatable relative to the swing support shaft 19 and the positioning pin 41. This developing unit swing drive lever 4
9 includes a cam control pin 50 controlled by the cam 48.
Is provided.

Therefore, when the operation lever 43 is rotated, the rotation of the operation lever 43 causes the developing unit swing drive lever 49 to rotate through the swing control surface 48 a of the cam 48 and the cam control pin 50. The developing unit 11 swings about the swing fulcrum shaft 19 relative to the swing fulcrum shaft 19 around the swing fulcrum shaft 19. I have. When the cam control pin 50 is fitted into the lock portion 48b of the cam 48 as shown in FIG. 7, the developing unit swing drive lever 49 is locked, and the developing unit 11 is separated from the photosensitive unit 5 by a sufficient distance. Is to be held.

Next, in the thus formed image forming apparatus 1 of this embodiment, the operation of pulling out and inserting the holding unit 12 into the main body 2 and the operation of contacting and separating the developing unit 11 from the photosensitive unit 5 are described. explain.

The description of these operations begins with the operation of pulling out the holding unit 12 from the mounting position on the main body 2 at the separated position of the developing unit 11 shown in FIG. At the separated position of the developing unit 11, each of the developing rollers 7a, 8a, 9
a, 10a are located far away from the OPC3. The operation lever 43 is set in the vertical direction, the cam control pin 50 is fitted in the lock portion 48b of the cam 48, and the developing unit 11 is locked at the separated position. Swing rock lever 37,
The developing unit regular position setting portions 37a and 38a and the guide surfaces 37b and 38b of the developing unit
Are greatly separated from the positioning pins 41 and 42 of the first embodiment. When the holding unit 12 is pulled in front of the main body 2 in this state, the holding unit side rail 22 extends to the intermediate rail 24, and the intermediate rail 24 extends to the main body side rail 23. , 24 are extended to the maximum, the holding unit 12 is set to the predetermined withdrawal position where the holding unit 12 is fully withdrawn from the main body 2.

At the pulled-out position of the holding unit 12, for example, the toner cartridges 7b, 8 of the developing units 7, 8, 9, 10
When the holding unit 12 is pushed into the main body 2 in order to mount the holding unit 12 at the mounting position of the main body 2, the holding unit side rail 22 is moved into the intermediate rail 24. Approach, and intermediate rail 24
Enters the main body side rail 23, and the ends of the rails 22, 24 abut against the corresponding stoppers 32, 32 to enter the respective rails 24, 23 to the maximum extent. It is set to the mounting position. When the holding unit 12 is pulled out and inserted, the relative positions of the developing unit 11 in the X and Y directions with respect to the photosensitive unit 5 do not change, and the developing unit 11 and the photosensitive unit 5 are in the state shown in FIG. ing.

When the holding unit 12 is set at a predetermined mounting position on the main body 2, the swing fulcrum pin 40 is fitted into the positioning hole 2c of the rear frame 2b without rattling. As a result, the holding unit 12 to which the swing fulcrum pin 40 is fixed is positioned with high precision with respect to the photoconductor unit 5 which is positioned and fixed to the main body 2 with high precision. Therefore, both the developing unit 11 and the photoconductor unit 5 are accurately positioned.

When the operating lever 43 is rotated clockwise in FIG. 7 after the holding unit 12 is set to the mounting position of the main body 2, the cam 48 rotates in the same direction, and the cam control pin 50 is moved from the lock portion 48b. Escape and swing control surface 48
It is gradually moved downward by being guided by a. Then, the developing unit 11 can swing counterclockwise around the swing fulcrum shaft 19 by its own weight. As the operation lever 43 rotates clockwise, the developing unit 11 swings counterclockwise. The developing unit swing drive lever 49 also integrally rotates counterclockwise about the swing fulcrum shaft 19.

On the other hand, simultaneously with the clockwise rotation of the operation lever 43, the swing fulcrum shaft 19 rotates clockwise in FIG. 7 via the operation drive gear 45, the intermediate gear 47 and the swing fulcrum shaft drive gear 46. The clockwise rotation of the pivot shaft 19 causes the first swing link levers 33 and 34 and the second
The swing lock levers 37, 38 rotate counterclockwise in FIG. 5 around the swing fulcrum pins 39, 40 via the swing link levers 35, 36. At this time, the first swing link levers 33, 34 rotate in the same direction as the swing fulcrum shaft 19, and the second swing link levers 35, 36 center on the connection point with the swing lock levers 37, 38. 5, it revolves in the counterclockwise direction and revolves in the counterclockwise direction about the swing fulcrum pins 39 and 40.

The rotation of the operation lever 43 causes the developing unit 11 to swing counterclockwise, thereby causing the developing unit 11 to rotate.
The developing unit X-direction positioning portion 11x and the developing unit Y-direction positioning portion 11y of the photoconductor unit 5 of the photoconductor unit 5 are simultaneously or almost simultaneously formed by the difference in diameter between the swing fulcrum shaft 19 and the through holes 11e and 11f. It contacts the unit X direction positioning section 5x and the photoconductor unit Y direction positioning section 5y. As a result, the developing unit 11 is directly positioned with respect to the photoconductor unit 5 in the X direction and the Y direction.

In this way, the developing unit 11 is positioned directly on the photoconductor unit 5 without the intervention of the main body 2, and the photoconductor unit 5 is positioned on the main body 2 with high accuracy. And the Y-direction positioning portions 5x and 5y are both positioned with high precision with respect to the OPC 3, and the holding unit 12 is accurately positioned with respect to the main body 2 and the photoconductor unit 5,
Further, since the developing units 11x and 11y are precisely positioned with respect to the pivot shaft 19, the positioning of the developing unit 11 and the photoreceptor unit 5 in the X and Y directions is performed with high accuracy. become. Note that in this state, as shown in FIG.
No. 8 guide surfaces 37b and 38b are both positioning pins 4
1,42 are in contact. In this state, even if the operation lever 43 is further rotated clockwise and the cam 48 is further rotated clockwise, the cam control pin 50 is not rotated.
Is not controlled at all by the swing control surface 48a.

Incidentally, even if the developing unit 11 is positioned in the X direction and the Y direction with respect to the photoreceptor unit 5 as described above, there is a gap between the swing fulcrum shaft 19 and the through holes 11e and 11f. As shown in FIG.
There is a possibility that the developing unit 11 is slightly depressed when the oblique upper right surface of 1f hits the oblique upper right surface of the swing fulcrum shaft 19. Therefore, when the operation lever 43 is further rotated clockwise to set the horizontal direction shown in FIG. 6, the swing lock levers 37, 38 are further rotated counterclockwise, so that the positioning pins 41, 42 are respectively set on the guide surfaces. It is slightly lifted by 37b and 38b and fits into the developing unit normal position setting portions 37a and 38a as shown in FIG. As a result, the developing unit 11 is pressed by the swing lock levers 37 and 38 and is firmly locked,
It is set and held at the regular horizontal position. Further, the developing unit X-direction positioning unit 11x and the developing unit Y-direction positioning unit 11y abut on the photoconductor unit X-direction positioning unit 5x and the photoconductor unit Y-direction positioning unit 5y, respectively. X
And the positioning in the Y direction is performed. In addition,
Further rotation of the operation lever 43 in the clockwise direction causes the cam 4 to rotate.
8 also rotates clockwise, at this time
Since the swing control surface 48a of the cam 48 does not control the cam control pin 50 at all, the developing unit 11 is not affected by the rotation of the cam 48.

In this manner, the swing fulcrum pins 39, 40
Are provided on the holding unit 12 so as to be positioned with high precision with respect to the pivot 19, and the positioning pins 4
Reference numerals 1 and 42 denote a developing unit X and a Y-direction positioning unit 11.
6 and 9, the developing unit 1 is positioned as shown in FIGS.
Numeral 1 indicates that the photoreceptor unit 5 is directly and more accurately positioned in both the X direction and the Y direction without the intervention of the main body 2 while being held at a regular horizontal position with high precision. Become.

In the state where the developing unit 11 shown in FIGS. 6 and 9 is positioned at the regular position with respect to the photosensitive unit 5 in the X and Y directions, the toner cartridges 7b, 8
To pull out the holding unit 12 from the main body for exchanging b, 9b, 10b, etc., first, the operation lever 43 is rotated counterclockwise in FIG. Then, each gear 45,
Since the swing fulcrum shaft 19 rotates in the same direction via 47 and 46, the swing lock levers 37 and 38 rotate clockwise, and the developing unit normal position setting units 37 a and 38 a move from the positioning pins 41 and 42 respectively. Come off. At this time, the cam 43 also rotates counterclockwise integrally with the operation lever 43, but the swing control surface 48 a of the cam 48 does not control the cam control pin 50, so that the developing unit 11 is not affected by the rotation of the cam 48. .

When the operation lever 43 is further rotated in the counterclockwise direction, the swing control surface 48a of the cam 48 controls the cam control pin 50, and the cam control pin 50 moves upward, so that the developing unit The swing drive lever 49 rotates clockwise around the swing fulcrum shaft 19. Then, the developing unit 11 is similarly rotated clockwise around the swing fulcrum shaft 19 and moves from the contact position with the photosensitive unit 5, so that the developing unit X direction positioning portion 11x and the developing unit Y direction Each of the positioning portions 11y is a photoconductor unit X-direction positioning portion 5x of the photoconductor unit 5.
And it is separated from the photoconductor unit Y-direction positioning portion 5y. Further, the swing lock levers 37, 38 are further rotated clockwise, and the developing unit regular position setting units 37a, 38
a largely deviates from the positioning pins 41 and 42, respectively.

When the operation lever 43 is rotated in the vertical direction shown in FIG. 7, the cam control pin 50 is engaged with the lock portion 48b of the cam 48, and the developing unit 11 is set and held at the separated position. At this time, when the cam control pin 50 moves from the swing control surface 48a of the cam 48 to the lock portion 48b, a click motion occurs in the operation of the operation lever 43.
The click feeling of the operation lever 43 at this time indicates that the developing unit 11 has been set and held at the separated position.
Thereafter, the holding unit 12 is pulled out of the main body 2 as described above. In this manner, the operation of pulling out and inserting the holding unit 12 into the main body 2 and the operation of contacting and separating the developing unit 11 from the photoconductor unit 5 are performed.

Next, an image forming operation of the image forming apparatus 1 of this example will be described. Normally, the holding unit 12 is held at a mounting position in the main body 2, and the developing unit 11 is held at a contact position where the developing unit 11 contacts the photoconductor unit 5. When the image forming apparatus 1 is not forming an image, the developing rollers 7a, 8a, 9a, and 10a are set to be separated from the OPC 3. When an image forming operation is performed in this state, the OPC 3 is turned off as shown in FIG. Rotates counterclockwise at
After C3 is charged by the charging roller, an image to be formed by the LSU 6 is exposed on the surface of the OPC 3, and OP
A latent image of this image is formed on the surface of C3. Next, the yellow developing device 7 is operated, and the yellow developing roller 7a is operated.
Is set to a development position by abutting or approaching the OPC 3 to develop a yellow image on the latent image on the OPC 3 to form a yellow toner image. Next, the yellow toner image is intermediate-transferred to the intermediate transfer body 13, and the residual toner on the OPC 3 after the intermediate transfer is removed by the photoconductor cleaner 4 and stored.

Next, after the OPC 3 is neutralized, the OPC 3 is charged and exposed again in the same manner as described above, and a latent image of an image to be formed is formed on the OPC 3. Next, the magenta developing device 8 is driven, magenta development is performed in the same manner as in the case of yellow, a magenta toner image is formed on the OPC 3, and this toner image is intermediately transferred to the intermediate transfer body 13. . Thereafter, development of cyan and black is sequentially performed in the same manner, and these cyan and black toner images are sequentially intermediate-transferred from the OPC 3 to the intermediate transfer body 13 and color-matched. In the transfer unit 14, the toner image color-matched by the intermediate transfer body 13 is taken out from the paper feed cassette 16 or the manual paper feed tray 17 by the paper feed rollers 52 and 53 and is conveyed under the control of the gate roller 54. The image is transferred to a transfer paper (not shown). Thereafter, the toner image on the transfer paper is fixed by the fixing device 15 and is conveyed to and stored in the paper discharge tray 18. Thus, a full-color image is formed by the image forming apparatus 1 of this example.

As described above, according to the image forming apparatus 1 of this embodiment, since the developing unit 11 is directly positioned on the photosensitive unit 5 without passing through the main body 2, the developing unit 11 and the photosensitive unit 5 Can be accurately positioned in the X and Y directions. Further, the holding fulcrum pin 40 provided on the rear frame of the holding frame 12 with high precision is fitted into the positioning hole 2c formed in the rear frame 2b of the main body with high precision.
Since the developing unit 11 is accurately positioned with respect to the photoconductor unit 5 positioned with high accuracy in the main body 2, the developing unit 11 can be positioned with higher accuracy with respect to the photoconductor unit 5. Further, since the front side of the holding unit 12 is free, when each developing roller 7a, 8a, 9a, 10a is set to the developing position without affecting the positional accuracy in the front-back direction, it follows the OPC3. Can be positioned. By the combination of positioning before and after the main body 2, each developing roller 7a, 8a, 9
a, 10a can be positioned in parallel with the OPC 3 with high precision.

Further, even if the positions of the developing unit X and the Y-direction positioning portions 11x and 11y vary with respect to the swing center of the developing unit 11 (that is, the centers of the through holes 11e and 11f), the swing fulcrum shafts 19 and through hole 11e, 1
Since this variation is absorbed by the difference in diameter from 1f, the developing unit X and Y direction positioning portions 11x and 11y of the developing unit 11 are changed to the photoconductor unit X and Y direction positioning portions 5x and 11x of the photoconductor unit 5. 5y at the same time. In addition, even if there is play between the swing fulcrum shaft 19 and the through holes 11e and 11f, the swing lock levers 37 and 38 accurately hold the developing unit 11 at the proper horizontal position. Thus, the positioning of the developing unit 11 and the photoreceptor unit 5 in the X and Y directions can be performed with even higher accuracy.

In the above-described example, the developing unit 11 is held by the holding unit 12 so as to be able to swing around the end on the side of the yellow developing device 7, but as shown in FIG. The end on the side 10 can also be held by the holding unit 12 so as to be swingable about the swing fulcrum shaft 19.

[0064]

As is apparent from the above description, according to the image forming apparatus of the present invention, since the developing unit is directly positioned on the photosensitive unit without interposing the main body,
The positioning between the developing unit and the photoconductor unit can be performed with higher precision and more easily. In this case, as the image formation speeds up, the separation distance between the developing roller and the photoconductor at the non-developing position of the developing roller is set to a minimum necessary distance, and the developing roller is exposed when the developing roller is pulled out from the main body of the developing unit. Even if the developing unit can be withdrawn sufficiently from the body and the developing roller can be pulled out of the main body without causing the developing roller to interfere with the photosensitive member, highly accurate positioning between the developing unit and the photosensitive member unit can be performed more quickly. As a result, the image forming apparatus of the present invention can sufficiently cope with high-speed image formation.

In particular, according to the second aspect of the present invention, since the developing unit is directly positioned in the upper, lower, left, and right directions of the photoconductor unit without interposing the main body, the upper, lower, right, left, and right sides of the developing unit and the photoconductor unit are positioned. Can be easily and accurately performed in two directions. According to the third aspect of the present invention, since the developing unit is directly positioned on the photoreceptor unit simultaneously in two directions, that is, up, down, left, and right, the positioning of the developing unit and the photoreceptor unit in the up, down, left, and right directions is further improved. It is possible to carry out with precision and more quickly. Furthermore, according to the invention of claim 4, since the developing unit is held in the proper position and the main body is positioned vertically and horizontally relative to the photoconductor unit, the developing unit and the photoconductor unit are positioned vertically and horizontally. Positioning can be performed with even higher precision.

Further, according to the fifth aspect of the present invention, the swing fulcrum pin of the swing lock member provided with high precision positioning in the holding unit is provided in the positioning hole formed in the main body with high precision positioning. Since the positioning is performed by fitting, the holding unit can be accurately positioned with respect to the photoconductor unit. As a result, the developing unit can be positioned with higher accuracy with respect to the photoconductor unit. Furthermore, according to the invention of claim 6, the swing fulcrum pins of the swing lock member provided on one side of the front and rear of the holding unit are provided with the swing fulcrum pins of the holding unit before and after the main body. The positioning unit is positioned with high precision with respect to the mounting position of the photosensitive unit on the same side as the side where the photosensitive unit is mounted. Since the other side of the developing device is made free, the positioning can be performed so as to follow the photosensitive member when the developing roller of each developing device is set to the developing position without affecting the positional accuracy in the front-rear direction of the main body. The combination of the positioning of the holding unit before and after the holding unit makes it possible to position each developing roller in parallel with the photoconductor with high accuracy.

According to the seventh aspect of the present invention, the swing fulcrum shaft of the swing lock member provided with high precision positioning in the holding unit is fitted into the positioning hole drilled in the main body with high precision. By doing so, the holding unit can be accurately positioned with respect to the photoconductor unit. As a result, the developing unit can be positioned with higher precision with respect to the photoconductor unit. Furthermore,
According to the invention of claim 8, the pivoting fulcrum shaft of the pivoting lock member is provided in one of the front and rear sides of the main body with the positioning hole drilled with high precision with respect to the mounting position of the photosensitive unit. Since the end on the same side as the side on which the positioning hole is provided is fitted to position one side before and after the holding unit, and the other side before and after the holding unit is free, When the developing rollers of the respective developing units are set to the developing positions, the positioning can be performed so as to follow the photosensitive member without affecting the positional accuracy in the front-rear direction of the main body. The combination of the positioning of the holding unit before and after the holding unit makes it possible to position each developing roller in parallel with the photoconductor with high accuracy.

Further, according to the ninth aspect of the present invention, since the swing lock member and the like are connected in a link by a predetermined number of levers, the swing lock member and the rotation transmission mechanism of the swing lock member are provided. The structure becomes simple.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an entire full-color image forming apparatus to which an embodiment of an image forming apparatus according to the present invention is applied.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 illustrates a photoconductor unit of the image forming apparatus illustrated in FIG.
FIG. 3 is a diagram illustrating a part of a developing unit and a holding unit in a partially enlarged manner.

4A and 4B show rails for pulling out and inserting the holding unit, FIG. 4A is a diagram showing a state in which the rail is pulled out to the maximum, and FIG. 4B is a cross-sectional view in a state where the rail is reduced.

FIG. 5 is a diagram illustrating an operation lock lever and a second positioning portion.

FIG. 6 is a diagram showing a configuration for rotationally swinging a developing unit and an operation lock lever by an operation lever.

FIG. 7 is a diagram illustrating a state in which the developing unit is set to a retract position.

FIG. 8 shows a state in which the developing unit comes into contact with the photoconductor unit;
FIG. 9 is a diagram illustrating a state in which the developing unit has slipped off from a normal position.

FIG. 9 shows the developing unit in a normal position in the X direction and Y direction.
It is a figure showing the state where it was positioned in the direction.

FIG. 10 is a diagram illustrating another example of the swing of the developing unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Main body, 2c ... Positioning hole, 3 ...
Photoconductor (OPC), 5 ... Photoconductor unit, 5d, 5e ...
Positioning pins of photoreceptor unit, 6: light scanning system exposure unit (LSU), 7: yellow developing device, 7a: yellow developing roller, 8: magenta developing device, 8a: magenta developing roller, 9: cyan developing device Developing device, 9a: cyan developing roller, 10: black developing device, 10a: black developing roller, 11: developing unit, 12: holding unit, 19: swing fulcrum shaft, 20, 21: guide rail,
22: holding unit side rail, 23: main body side rail, 2
4: middle rail, 33, 34: first swing link lever,
35, 36: second swing link lever, 37, 38: swing lock lever, 37a, 38a: developing unit regular position setting portion, 37b, 38b: guide surface, 39, 40: swing fulcrum pin, 40a: extension Parts, 41, 42 ... positioning pins, 4
Reference numeral 3 denotes an operation lever, 45 denotes an operation drive gear, 46 denotes a swing fulcrum shaft drive gear, 47 denotes an intermediate gear, 48 denotes a cam, 48a denotes a swing control surface, 48b denotes a lock portion, and 49 denotes a developing unit swing drive lever. 50 ... Cam control pin

Claims (9)

[Claims] 1. A holding unit provided on a main body so as to be able to be pulled out and inserted in a front-rear direction of the main body between a mounting position which is positioned and mounted in the main body and a drawing position which is drawn out of the main body, and A photoreceptor unit, comprising: a developing unit that is positioned and swingably provided on the unit and holds a predetermined number of developing units; and a photoreceptor unit that is positioned and attached to the main body and holds a photoreceptor. The photosensitive unit side positioning section is positioned and provided on the developing unit, and the developing unit side positioning section is positioned and provided on the developing unit, and the developing unit swings, thereby positioning the developing unit side. The portion contacts the photoconductor unit side positioning portion, thereby positioning the developing unit and the photoconductor unit. An image forming apparatus characterized in that it is adapted to be performed. 2. The photoreceptor unit side positioning section includes a photoreceptor unit side left / right positioning section for performing main body left / right positioning and a photoreceptor unit side vertical positioning section for performing vertical positioning of the main body. The developing unit side positioning section is configured to contact the photoconductor unit side left / right positioning section to perform positioning of the developing unit and the photoconductor unit in the main body left / right direction. And a developing unit-side vertical positioning portion that abuts on the photoconductor unit-side vertical positioning portion and performs positioning of the developing unit and the photoconductor unit in the main body vertical direction. 2. The image forming apparatus according to 1. 3. A predetermined play is provided between the holding unit and the developing unit at a swinging fulcrum of the developing unit. The abutment on the body unit side left / right positioning unit and the abutment of the developing unit side vertical positioning unit on the photoconductor unit side vertical positioning unit are performed simultaneously or almost simultaneously. The image forming apparatus according to claim 2, wherein 4. A developing unit swing lock means for holding the developing unit at a proper position when positioning the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body, is provided. 4. The image forming apparatus according to claim 3, wherein the image forming apparatus is held in a proper position by a developing unit swing lock unit and positioned relative to the photoreceptor unit in up, down, left, and right directions. 5. The developing unit swing lock means includes: a positioning member provided on the developing unit, the positioning member being positioned with respect to the developing unit side left / right positioning unit and the developing unit side vertical positioning unit. The developing unit and the photoreceptor unit are rotatably provided on a swing fulcrum pin positioned and provided on the holding unit, and rotate about the swing fulcrum pin in conjunction with the swing of the developing unit. And a swing lock member that holds the developing unit in a proper position by engaging with the positioning member when positioning the main body in the up, down, left, and right directions, and when the holding unit is mounted at a mounting position in the main body. Wherein the swing fulcrum pin is fitted into a positioning hole provided in the main body so as to be positioned with respect to the mounting position of the photoconductor unit. And, the image forming apparatus according to claim 4, characterized in that the holding unit is positioned with respect to the photosensitive member unit. 6. A swing fulcrum pin of the swing lock member is provided on one of the front and rear sides of the holding unit, and the positioning hole is provided on the swing fulcrum of the holding unit before and after the main body. The image forming apparatus according to claim 5, wherein the image forming apparatus is provided on the same side as the side on which the pins are provided. 7. The developing unit swing lock means includes: a positioning member provided on the developing unit, the positioning member being positioned with respect to the developing unit side left / right positioning unit and the developing unit side vertical positioning unit; The developing unit and the photoreceptor unit are rotatably provided on an oscillating fulcrum shaft positioned and provided on the holding unit, and are rotated around the oscillating fulcrum shaft in conjunction with the swing of the developing unit. And a swing lock member that holds the developing unit in a proper position by engaging with the positioning member when positioning the main body in the up, down, left, and right directions, and when the holding unit is mounted at a mounting position in the main body. The swinging fulcrum shaft is fitted into a positioning hole provided on the main body, the positioning shaft being positioned with respect to the mounting position of the photoconductor unit. The image forming apparatus according to claim 4, characterized in that the holding unit is positioned with respect to the photosensitive member unit. 8. The positioning hole is provided on one of the front and rear sides of the main body, and a swing fulcrum shaft of the swing lock member is provided on a side of the holding unit on which the positioning hole is provided. 8. The image forming apparatus according to claim 7, wherein an end on the same side as the end is fitted into the positioning hole. 9. The swing lock member comprises a swing lock lever, and the swing lock lever is connected to a swing fulcrum shaft of the developing unit via a predetermined number of link levers. The developing unit is held in a proper position by engaging with the positioning member at the time of positioning the developing unit and the photoreceptor unit in the vertical and horizontal directions of the main body by interlocking with the swinging. The image forming apparatus according to any one of claims 5 to 8, wherein: