JP2002174952A - Supporting mechanism for development unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly and surely conduct the positioning action and set position releasing action of a developing unit 8 to/from a photosensitive drum 2. SOLUTION: A developing unit supporting mechanism is provided with the photoreceptor drum 2, with a developing unit 8 engaged and supported with/by a rail unit 20 and with a cam 40. Axial parts 24, 25 supported by side plates 18, 19 so as to be rotated around an axial line L are formed on one end of the rail unit 20 and the other end, respectively. A supported part 15b coaxially supported by being engaged with the axial part 24 formed on one end part of the unit 20 so as to be freely separated in the axial line L direction is formed on one end part of a development housing 10. A positioning means for locking the other end part of the housing 10 on the other end part of the unit 20 so as to be freely separated in the axial line direction is arranged between the other end part of the unit 20 and the other end part of the housing 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a laser printer,
An image provided such that a paper transport path passing through a transfer unit (transfer area) of a photosensitive drum, particularly a support mechanism of a developing unit provided in an image forming machine such as a facsimile or an electrostatic copying machine extends in a vertical direction. The present invention relates to a developing unit support mechanism applied to a forming machine.

[0002]

2. Description of the Related Art A typical example of an image forming machine, for example, an electrostatic copying machine, includes a photosensitive drum, a main charger, an LSU (laser scanning unit), a developing unit including a developing roller, a transfer roller, a cleaning device, and a charge removing device. It has a device and the like. Of these, in a copying machine in which a paper conveyance path passing through a transfer section formed between a photosensitive drum and a transfer roller is arranged to extend in a vertical direction, the copier is provided with a developing unit due to its layout. The developed developing roller is disposed so as to contact the lowermost position on the outer peripheral surface of the photosensitive drum. The developing unit provided in such a copying machine is slidably supported by a rail unit rotatably supported about an axis parallel to the axis of the photosensitive drum. A cam is provided on the frame of the copier body, and the developing unit is supported by the rail unit so that the developing roller contacts the rail unit and the surface of the photosensitive drum around the rotation axis of the rail unit. The developing roller is configured to be rotatable between a contacted operating position and a non-operating position in which the developing roller is separated downward from the surface of the photosensitive drum.

[0003]

Generally, the developing unit is designed so that it is slidably supported with some play without any particular positioning with respect to the rail unit. is there. For this reason, when the developing roller is rotated around the rotation axis of the rail unit together with the rail unit and positioned at the operating position as described above, the developing roller is moved to the photosensitive drum due to the play. There is a risk of hitting against the surface,
It is relatively difficult to ensure the positioning accuracy of the developing unit with respect to the photosensitive drum as desired. In order to solve this problem, it is conceivable to provide a rotating shaft for the developing unit separately from the rotating shaft of the rail unit, and to rotate the developing unit around the rotating shaft. However, in this means, since the developing unit and the rail unit are rotated around separate rotation axes, the rotation of the developing unit and the rail unit, that is, the positioning operation of the developing unit with respect to the photosensitive drum and the setting position releasing operation May not be performed smoothly and reliably, and the positioning accuracy of the developing unit with respect to the photosensitive drum may not be secured as desired. In addition, the structure of the support mechanism of the developing unit becomes complicated, which increases the cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel developing unit support mechanism which facilitates smooth and reliable operation of positioning the developing unit with respect to the photosensitive drum and releasing the set position. is there.

Another object of the present invention is to provide a novel developing unit support mechanism which can easily ensure the positioning accuracy of the developing unit with respect to the photosensitive drum as desired.

Still another object of the present invention is to provide a novel developing unit support mechanism which has a simple structure as a whole and enables cost reduction, in addition to the above objects.

[0007]

According to the present invention, a frame means provided in an image forming machine including a photosensitive drum includes:
A rail unit rotatably supported about an axis parallel to the drum; a developing housing; and a developing roller disposed in the housing, and fitted to the rail unit so as to be detachable from one end of the rail unit in the axial direction. The developing unit supported and supported is selected between an operating position in which the developing roller is brought into contact with the surface of the drum and a non-operating position in which the developing roller is separated substantially downward from the surface of the drum. And a cam unit that can be moved in a moving direction. A shaft unit is formed at one end and the other end of the rail unit so as to be rotatably supported on the frame unit around the axis. A supported portion is formed at one end of the housing and is coaxially supported by a shaft formed at one end of the rail unit so as to be detachably fitted in the axial direction. Positioning means is provided between the other end of the developing unit and the other end of the developing housing for locking the other end of the developing housing to the other end of the rail unit so as to be detachable in the axial direction. When the unit is fitted to the rail unit and moved toward the other end, the supported portion at one end of the developing housing is fitted and supported by the shaft at one end of the rail unit, and the other end of the developing housing is supported. Is fixed to the other end of the rail unit via a positioning means, is mounted on the rail unit, and can rotate around the common axis with the rail unit. Is done.

A coaxial support hole is formed in a shaft formed at one end of the rail unit, and a supported pin formed at one end of the developing housing is a locked pin which can be fitted into the support hole. A positioning hole formed at the other end of the rail unit, and a positioning locked formed at the other end of the developing housing and detachably locked to the locking hole. And a pin portion. The position of the axis is defined so that the developing unit mounted on the rail unit can rotate downward by its own weight together with the rail unit from the operating position to the non-operating position according to the action of the cam means. Is preferred. The cam means includes a cam which can be selectively rotated between an operating position where the developing housing is directly pressed and pushed upward and a non-operating position which is separated downward from the bottom surface. The developing housing is rotatable from a non-operating position to an operating position so as to push up the developing housing while moving relative to the bottom surface of the developing housing in a direction away from the axis L in the radial direction. When the cam is rotated from the non-operation position to the operation position, the bottom surface of the developing housing is pushed up by the cam, and the developing unit rotates together with the rail unit around the axis from the non-operation position upward. Preferably, it is moved to the operating position. The cam means
A shaft rotatably supported on an axis parallel to the axis of the photosensitive drum, a case member disposed at both ends of the shaft, and a frame member mounted on the frame means via spring means. And each of the cams is biased radially outwardly of the shaft by spring means such that when each of the cams is positioned in the operative position, each of the cams comprises:
Preferably, the bottom surface of the developing housing is elastically pressed. The rail unit includes a flat plate-shaped rail main body extending linearly in the axial direction with a predetermined width, and one end in the width direction at both ends in the longitudinal direction of the rail main body, and A through hole is formed at one end of the developing unit. When the developing unit is mounted on the rail unit, a part of the bottom surface of the developing housing is exposed downward through each of the through holes of the rail unit. Preferably, each of the cams presses directly against a corresponding bottom surface of the developer housing through a corresponding through hole in the rail unit as each is pivoted toward the operative position. The frame means is composed of a pair of side plates arranged at intervals in the axial direction, each of the side plates is formed with a support hole having an axis common to the axis, and the rail unit has a predetermined width. A flat plate-shaped rail body extending linearly in the axial direction; and one end in the width direction at both ends in the longitudinal direction of the rail body, extending outward from one end opposite to the photosensitive drum. And a supported wall which stands upright at a distance from each other and is opposed to each other, and the shaft portion is provided on each of the supported walls, from one end of the rail unit in the axial direction from each of the supported walls. The shaft portion in the supported wall at one end of the rail unit is formed so as to extend in the direction toward the other end, and the support hole of one side plate is
In addition, the shaft unit in the supported wall at the other end of the rail unit is detachably and rotatably inserted into the support hole of the other side plate, so that the rail unit is rotatable on each of the side plates. Is preferably supported. Rotation restricting means for restricting the rotation of the rail unit is provided between the rail unit and one of the side plates so that the developing unit rotates from the operating position and stops at the non-operating position. Is preferred. The rotation restricting means includes at least one mounting hole formed at a position radially outward of the support hole in one side plate, and a radially outer position of the shaft portion in one of the supported walls of the rail unit. At least one elongated hole formed at a position and extending in a tangential direction or a circumferential direction of an imaginary circle centered on the axis of the shaft portion, and a rotation restricting member fixed to the mounting hole through the elongated hole. In the state where the developing unit is located at the operating position together with the rail unit, one end in the longitudinal direction of the long hole of the rail unit is positioned with a gap with respect to the outer peripheral surface of the rotation regulating pin of one of the side plates. When the developing unit is rotated about the axis integrally with the rail unit in a direction in which the developing roller is substantially separated downward from the surface of the photosensitive drum, the longitudinal direction of the long hole of the rail unit is changed. The end surface is regulated the pivoting of the rail unit is brought into contact with the outer peripheral surface of the rotation restriction pin, the developing unit is positioned at the inoperative position with the rail unit, it is preferable. A support hole having a common axis with the axis is formed in the shaft of one of the supported walls of the rail unit, and at one end in the longitudinal direction of the developing housing, the photosensitive drum in the width direction of the developing housing is formed. A protruding wall is formed extending on the opposite side, and a locked pin portion is formed on the protruding wall and extends in a direction from the one end of the developing housing toward the other end in the axial direction. When fitted to the unit and moved from one end to the other end, the locked pin portion is removably fitted to a support hole formed in the shaft portion of one of the supported walls of the rail unit. ,
Is preferred. At least one locking hole extending in the axial direction is formed in the other supported wall of the rail unit, and one end of the axial direction and the other end of the developing housing is formed at the other longitudinal end of the developing housing. At least one positioning locked pin portion extending from the first to the other end is formed, and when the developing unit is fitted to the rail unit and moved from one end to the other end, the positioning locked pin is formed. Preferably, the portion is detachably locked in the locking hole.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a support mechanism for a developing unit constituted according to the present invention will be described below in more detail with reference to the accompanying drawings.

Referring to FIG. 1, a photosensitive drum 2 is provided in a copying machine main body of a copying machine (not shown) which is an image forming machine, and a cleaning device 4 is provided around the photosensitive drum 2.
The main charger 6 provided in the housing of the cleaning device 4 and the developing housing 10 of the developing unit 8 (see FIG. 9).
The image forming elements such as the developing roller 12 and the transfer roller 14 are disposed. FIG. 1 of the developing unit 8
, An LSU (laser scanning unit) is disposed on the right side, and a toner container 15 is disposed above the LSU. Numeral 16 indicates a paper transport path, and the paper transport path 16 is provided so as to extend in a vertical direction at a transfer portion formed between the photosensitive drum 2 and the transfer roller 14. Number 17 indicates a registration roller,
The registration roller 17 is disposed on the paper transport path 16 upstream of the transfer section. In FIG. 1, 2
The dashed line indicates the irradiation path of the laser light emitted from the LSU to the surface of the photosensitive drum 2, and the laser light passes through the developing unit 8, the toner container 15, the housing of the cleaning device 4 and the main charger 6. Are laid out so as to irradiate the surface of the photosensitive drum 2 through a gap between the two. An unillustrated paper feed cassette or the like is arranged at a position upstream of the transfer section of the paper transport path 16 and below the copier main body.
A fixing device, a discharge roller, a discharge tray, and the like (not shown) are disposed downstream of the transfer unit and above the main body of the copying machine. At the top of the main body of the copying machine, a document transport device, a document reading device, and the like (not shown) are provided.

While a predetermined number of documents are moved by the document feeder, the image of each document is read by the document reading device and stored as image information. The stored image information is irradiated by the LSU onto the surface of the photosensitive drum 2 uniformly charged by the main charger 6, and an electrostatic latent image is formed on the surface of the photosensitive drum 2. This electrostatic latent image is developed by the developing unit 8 with the developer carried on the developing roller 12. On the other hand, the sheet conveyed from the sheet cassette is conveyed toward the transfer unit at a predetermined timing by the registration roller 17. While the sheet passes through the transfer section, the transfer roller 14 transfers the toner image formed on the surface of the photosensitive drum 2 to one side of the sheet. The sheet having the toner image transferred on one side is conveyed to a fixing device, and the image is fixed on one side of the sheet while passing through the fixing device. The sheet having the toner image fixed on one side is discharged onto a discharge tray by a discharge roller. As described above, a toner image is formed on one side of the sheet while the sheet is transported through the sheet transport path 16. The above-described basic configuration and copying operation of the copying machine may use a well-known form, and do not form a feature of the present invention, so that further detailed description will be omitted.

Next, a support mechanism of the developing unit 8 according to the present invention will be described. With reference to FIG. 1 and FIGS.
The copier main body is spaced apart in the front-rear direction of the copier main body (the front and back direction in FIG. 1, the left-right direction in FIG. 4), and in the left-right direction of the copier main body (the left-right direction in FIG. 1, the up-down direction in FIG. 4). Front plate 18 and rear plate 1 extending in parallel
9 are provided. The photosensitive drum 2 has a front plate 18 and a rear plate 19 (see FIG. 4) constituting frame means.
It is rotatably arranged between them. The support mechanism of the developing unit 8 includes a front plate 18 and a rear plate
And a rail unit 20 rotatably supported about an axis L parallel to the rotation axis of the rail unit 20. The rail unit 20 has an axis extending from the front end in the front-rear direction at one end to the rear end in the front-rear direction at the other end. And a developing unit 8 which is fitted and supported so as to be detachable in the L direction. FIG.
3, the symbol O indicates the axis L viewed in the axial direction,
The rotation axis of the rail unit 20 is shown. In the following description, the front-rear direction and the longitudinal direction generally indicate the front-rear direction of the copying machine body described above, and the width direction generally indicates the left-right direction of the copying machine body described above. Direction shall be indicated. The front side and one end side are shown in FIG.
4, the right side in FIG. 4, the rear side and the other end side refer to the back side (rear side) in FIG. 1 and the left side in FIG. 4. The rotation axis direction and the axis L direction of the photoreceptor drum 2 coincide with the front-back direction and the longitudinal direction.

Referring mainly to FIGS. 5, 7 and 8,
The rail unit 20 is connected to the front side plate 1 as described later.
8 and a state supported by the rear side plate 19, a flat plate-like rail body 21 extending linearly in the direction of the axis L with a certain width, and both ends in the longitudinal direction of the rail body 21 At the end extending in the width direction at one end, and extending outward and outward from one end opposite to the photosensitive drum 2, the front supported wall 22 and the rear supported wall 22 facing each other at an interval in the longitudinal direction. And a supported wall 23. A rail main body 21 formed of a steel plate has a flat bottom wall 21 a having a constant width and linearly extending in the longitudinal direction, and a linearly extending bottom wall 21 a along both widthwise ends of the bottom wall 21 a. A side wall 21b which is present and stands up to the same height from the upper surface of the bottom wall 21a, and a flange 2 which extends at a right angle from the upper end of each of the side walls 21b by a certain width in a direction approaching each other.
1c. With the above configuration, the rail body 2
A pair of guide grooves are formed at both ends in the width direction of the bottom wall 21a so as to extend linearly along both ends in the width direction. A pair of guide grooves are formed so as to face each other. An upright flange 21d is formed at the other longitudinal end of the rail body 21. A rectangular through hole 21e is formed at one end in the width direction at both ends in the longitudinal direction of the rail main body 21 and at one end on the photosensitive drum 2 side.

The front supported wall 22, which can be integrally formed of a suitable synthetic resin, is provided on the rail body 2 from its bottom.
1 is provided with a base 22a extending in the width direction of the photosensitive drum 2 and in the direction toward the photosensitive drum 2. The portion of the base 22a on the photosensitive drum 2 side is fixed to the lower surface of the front end (one end) of the rail main body 21 with screws (not shown). The front supported wall 22 is formed in a vertically elongated rectangular shape as viewed in the longitudinal direction of the rail main body 21. The rear supported wall 23, which can be integrally formed from an appropriate synthetic resin,
A base wall portion 23a is provided to extend from the side in the width direction of the rail body 21 in the direction toward the photosensitive drum 2. The front upright surface of the base wall portion 23a on the front side of the photosensitive drum 2 side portion is fixed to an upright flange 21d of the rail main body 21 with screws (not shown). Rear supported wall 23
In the base wall portion 23a, at least one locking hole 23b extending in the direction of the axis L, in the embodiment, two locking holes 23b are formed at intervals in the width direction. In the embodiment, each of the locking holes 23 b is formed on a positioning boss formed on the rear supported wall 23. At a position near the upper end of the front supported wall 22, a front shaft portion 24 extends from the front supported wall 23 in the direction of the axis L and in the direction from the front end of the rail body 21 to the rear end of the rail unit 20. It is formed so that it comes out. The front shaft portion 24 has a cylindrical shape with a coaxial support hole 24a formed therein.
a is formed so as to penetrate the front supported wall 23 in the front-rear direction. At a position near the upper end of the rear supported wall portion 23, a rear shaft portion 25 is provided in the direction of the axis L from the rear supported wall portion and in the direction from the one end of the rail body 21 to the other end of the rail unit 20. It is formed to extend. The rear shaft portion 25 has a cylindrical shape. Support holes 18a and 19a having a common axis L are formed in the front side plate 18 as one side plate and the rear side plate 19 as the other side plate (see FIG. 4).

Referring to FIG. 4, the front shaft portion 24 of the front supported wall 22 is inserted into the support hole 18a of the front side plate 18 so as to be detachable and rotatable from the front side. The rail unit 20 is rotatably supported by the front plate 18 and the rear plate 19 by the rear shaft portion 25 being rotatably inserted into the support hole 19a of the rear plate 19 from the front side. The front plate 18 and the rear plate 19 have through holes (not shown) that allow the rail unit 20 to be inserted and supported from the front side to the rear side for the support. These through holes are also formed in a size that allows the developing unit 8 to be removably fitted and mounted on the rail unit 20 as described later, and the developing unit 8 is mounted on the rail unit 20. It is formed in such a size that it is allowed to rotate integrally within a predetermined angle range in the state of being moved.

As will be apparent from the following description, the developing unit 8 is detachably mounted on the rail unit 20 and the developing roller 1 is moved by a cam means 30 described later.
2 is selectively moved to an operating position where the developing roller 12 is in contact with the surface of the photosensitive drum 2 and a non-operating position where the developing roller 12 is separated substantially downward from the surface of the photosensitive drum 2. The position of the axis L is defined so that the developing unit 8 mounted on the rail unit 20 can rotate downward by its own weight together with the rail unit 20 from the operation position to the non-operation position according to the action of the cam means 30. ing. This configuration ensures that the rotation of the developing unit 8 from the operating position to the non-operating position is smooth and reliable together with the rail unit 20 without applying any special means. In order to allow the above operation, the rotation of the rail unit 20 is provided between the rail unit 20 and the front side plate 18 so that the developing unit 8 is rotated from the operation position and stopped at the non-operation position. Rotation restricting means for restricting is provided.

Referring to FIG. 5 to FIG. 8, the rotation restricting means
At least one attachment hole formed in the front side plate 18 at a position radially outward of the support hole 18a, and in the embodiment, two attachment holes 18b (only one of them is shown in FIG. 6). ), In the front supported wall 22 of the rail unit 20, in a tangential direction or a circumferential direction of an imaginary circle formed radially outside the front shaft portion 24 and centered on the axis O of the front shaft portion 24. At least one extending
It comprises a plurality of long holes, in the embodiment, two long holes 22b, and a rotation regulating pin 26 fixed to the corresponding mounting hole 18b through each of the long holes 22b. Each of the mounting holes 18b is formed at an interval in the vertical direction of the front side plate 18 and at an angle of 180 ° from each other.
Are substantially positioned on a virtual circle having the same diameter and the same diameter as the virtual circle. Each of the long holes 22b is formed at intervals in the vertical direction of the front supported wall 22 and at an angular interval of substantially 180 ° from each other. On the front surface of the front supported wall 22 where each of the mounting holes 18b is formed,
A recess 22c having a depth such that the head of the rotation regulating pin 26 does not project from the front surface is formed. In a state where the developing unit 8 is positioned at the operating position together with the rail unit 20 as described later (see FIG. 1), one end face of each of the long holes 22b of the rail unit 20 in the longitudinal direction (the upper side in FIG. 1). The right end face in the hole 22b and the left end face in the lower long hole 22b) are positioned with a gap from the outer peripheral surface of the rotation regulating pin 26.
When the developing unit 8 is rotated about the axis L together with the rail unit 20 in a direction in which the developing roller 12 is separated substantially downward from the surface of the photosensitive drum 2 as described later, The one end surface of each of the long holes 22b in the longitudinal direction is brought into contact with the outer peripheral surface of the rotation restricting pin 26 to restrict the rotation of the rail unit 20, and the developing unit 8 is moved together with the rail unit 20 to the non-operation position. (See FIG. 2).

Referring to FIG. 3 to FIG. 5 and FIG. 9, a developing unit 8 includes a developing housing 10 which can be integrally formed of an appropriate synthetic resin, and a developing roller 12 provided in the developing housing 10. It has. In the developing housing 10, a developer composed of toner and carrier particles is stored, and a stirring and conveying mechanism (not shown) is provided. On both sides of the developing roller 12 in the axial direction, a gap setting roller 12a which comes into contact with the surface of the photosensitive drum 2 (see FIG. 9).
Are arranged coaxially. Flanges 13 are formed on both sides in the width direction at the lower end of the developing housing 10 so as to extend linearly outward by a certain width outward in the width direction.
Each of the flange portions 13 is formed to have a rectangular cross section. At the front end in the longitudinal direction of the developing housing 10, a protruding wall 15 is formed which extends in the width direction of the developing housing 10 on the opposite side to the photosensitive drum. At the upper end of the protruding wall 15, a toner supply port 15a is formed (see FIG. 9). The protruding wall 15 is formed with a locked pin portion 15b extending in the longitudinal direction (the direction of the axis L) of the developing housing 10 and extending from the front end to the rear end of the developing housing 10. At the rear end in the longitudinal direction of the developing housing 10, at least one positioning locked pin portion 17b extending in the direction of the axis L from one end of the developing housing toward the other end, and in the embodiment, two positioning locked pin portions 17b are provided. The positioning locked pin portions 17b are formed at intervals in the width direction. Other configurations of the developing unit 8 may use a known configuration, and further description will be omitted.

The developing unit 8 configured as described above
Each of the flange portions 13 of the developing housing 10 is fitted into the pair of guide grooves formed in the rail main body 21 of the rail unit 20, and is guided by each of the guide grooves to move from the front end of the rail main body 21 to the rear end. Moved towards the edge.
When the developing unit 8 is moved from the front end to the rear end of the rail unit 20, the locked pin portion 15 b of the projecting wall 15 of the developing housing 10 is moved to the front shaft portion 24 of the front supported wall 22 of the rail unit 20. It is removably fitted into the formed support hole 24a. Further, each of the positioning locked pin portions 17b formed at the rear end of the developing housing 10 is detachable from each of the locking holes 23b formed in the base wall portion 23a of the rear supported wall 23 of the rail unit 20. Is locked.
With the developing unit 8 mounted on the rail unit 20, a part of the bottom surface of the developing housing 10 is exposed downward through each of the through holes 21 e formed in the bottom wall 21 a of the rail main body 21 of the rail unit 20. Is done. Each of the exposed bottom surfaces defines a contact surface of a cam 40 described later.

As described above, the developing unit 8 is detachably mounted on the rail unit 20. The mounting is performed in a state where the rail unit 20 is positioned at the non-operation position. The mounting is easily and reliably performed by a simple operation of moving the developing unit 8 from the front end to the rear end of the rail unit 20. The detaching operation of the developing unit 8 from the rail unit 20 is easily and reliably performed by a simple operation of pulling out the developing unit 8 from the rail unit 20 in the opposite direction. In a state where the developing unit 8 is mounted on the rail unit 20, the upper surface of each of the flange portions 13 of the developing housing 10 has a downward surface in the corresponding guide groove (a flange 21c formed at both ends in the width direction of the rail body 21). With such a configuration, the backlash between the developing unit 8 and the rail unit 20 can be minimized. As a result, the operation of positioning the developing unit 8 with respect to the photosensitive drum 2 and the operation of releasing the set position can be performed smoothly and reliably. Also,
The positioning accuracy of the developing unit 8 with respect to the photosensitive drum can be easily secured as desired. As described above, in a state where the developing unit 8 is mounted on the rail unit 20, the upper surface of each of the flange portions 13 of the developing housing 10 is formed with the downward surface of the corresponding guide groove (formed at both ends in the width direction of the rail body 21). The lower surface (lower surface) of the developing housing 10 in the mounted state.
A slight clearance (for example, about 1.5 mm) is formed between the rail body 21 and the upper surface of the bottom wall 21a of the rail main body 21. Due to the formation of the clearance, the rail unit 2 of the developing unit 8 when the developing unit 8 is pulled out from the rail unit 20 in the opposite direction and when the developing unit 8 is mounted.
The slide movement with respect to 0 is easy and smooth. In addition,
Each of the locking holes 23b formed in the base wall portion 23a of the rear supported wall 23 of the rail unit 20 and the developing housing 10
Each of the positioning locked pin portions 17b formed at the rear end of the developing unit 10
Positioning means is provided at the rear end portion of the carriage 0 so as to be detachable in the direction of the axis L.

The support mechanism for the developing unit according to the present invention also includes a developing unit 8 and an operating position where a developing roller 12 (more precisely, a gap setting roller 12a) is brought into contact with the surface of the photosensitive drum 2; A cam means 30 is provided which can be selectively moved to a non-operating position where 12 is substantially separated downward from the surface of the photosensitive drum 2.
Referring to FIGS. 10 to 12, the cam means 30 is connected to the front side plate 1.
A shaft 32 (see also FIG. 4) whose both ends are rotatably supported between the shaft 8 and the rear side plate 19, and at least one cam mechanism provided on the shaft 32. In the embodiment, both ends of the shaft 32 Is provided with a pair of cam mechanisms 34 disposed at the same position. Shaft 32
Are arranged so as to have an axis parallel to the axis of the photosensitive drum (therefore, an axis parallel to the axis L). Since each of the cam mechanisms 34 has the same configuration as that of the embodiment, only one of them will be described.

The cam mechanism 34 has a case member 36 provided on the shaft 32 and a cam 40 mounted on the case member 36 via a compression coil spring 38 as a spring means. In FIG. 11, the illustration of the compression coil spring 38 is omitted. The case member 36 includes a pair of side walls 36a extending in the radial direction of the shaft 32 at intervals in the axial direction of the shaft 32, and a bridging wall 36b connecting one end of each of the side walls 36a in the width direction. One end of each of the side walls 36a is mounted so as to be able to rotate integrally with the shaft 32. Side wall 3
Each of the grooves 6a has a locking groove 36c extending from the other end in the width direction in a tangential direction of the shaft 32 and further extending outward in the radial direction of the shaft 32. The cam 40 is a block having a curved cam surface formed at the upper end, and has a support pin 42 projecting outward on both sides on both sides. In the center of the lower end of the cam 40, a cylindrical portion 4 extending downward
4 are formed. A guide pin 46 is fastened to the shaft 32 at a position between each of the side walls 36 a by a nut 48. The guide pin 46 is disposed so as to penetrate the axis of the shaft 32 at right angles and to extend radially outward between the respective side walls 36a. The cam 40 is formed such that each of the support pin portions 42 corresponds to the corresponding locking groove 3 of the case member 36.
6c, the cylindrical portion 44 is fitted to the guide pin 45 so as to be relatively movable. A compression coil spring 38 is interposed between the nut 46 and the lower end surface of the cam 40. Cam 4
0 is constantly urged radially outward of the shaft 32 by the compression coil spring 38. When the cam 40 receives a predetermined force or more inward in the radial direction against the spring force of the compression coil spring 38, the cam 40 is moved inward in the radial direction according to the force. The movement of the cam 40 is caused by the support pin 4
2 can move radially inward along the corresponding locking groove 36c, and the cylindrical portion 44
That can move radially inward along the

A gear 50 is mounted on one end of the shaft 32 so as to be able to rotate integrally. When the shaft 32 is supported between the front plate 18 and the rear plate 19, the gear 50 is positioned on the front side of the front plate 18 close to the front plate 18 (see FIG. 4). Although the mounted state is not shown, the cam 4 is located on the left side of the front side plate 18 adjacent to the gear 50.
The operation levers 52 are rotatably supported via shafts (not shown). A gear 54 is mounted on the shaft of the operation lever 52 so as to be able to rotate integrally. Gear 50
And 54 are meshed with each other.

FIG. 1 shows a case where the developing unit 8 is mounted on the rail unit 20 and each of the cams 40 is connected to the developing housing 10.
(The bottom surface exposed through each of the through holes 21 e of the bottom wall 21 a of the rail body 21) is positioned at an operation position where the bottom surface is directly pressed and pushed upward through the through holes 21 e, and the developing roller 12 (more specifically, Has a gap setting roller 1
2a) is set to an operation position where the photosensitive drum 2 is brought into contact with the surface of the photosensitive drum 2. Each of the cams 40 and the operation lever 52 are positioned substantially upright. When each of the cams 40 is positioned in the operative position, each of the cams 40 is forcibly moved inward in the radial direction against a spring force of the compression coil spring 38 by a predetermined stroke to elastically move the bottom surface of the developing housing 10. Pressure. By this elastic action, each of the gap setting rollers 12a is uniformly pressed against the surface of the photosensitive drum 2 with a predetermined pressure. This function makes it possible to easily secure the positioning accuracy of the developing unit 8 with respect to the photosensitive drum 2 as desired. A rib 10a is formed on the bottom surface of the developing housing 10 to which each of the cams 40 is pressed, in proximity to the front side of the cam 40 (the front side in the front-rear direction) (see a two-dot chain line in FIG. 12). Each of the ribs 10a functions to prevent the longitudinal movement of the developing housing 10 from moving backward. The cam 40 and the operation lever 52 are positioned in an upright state. A through hole 52a is formed in the operation lever 52 (see FIG. 10), and a screw hole (not shown) is formed at a corresponding position of the front side plate 18 so that the operation lever 52 is aligned in the upright state. Through hole 52
The operation lever 52 can be releasably fastened to the front side plate 18 by a screw (not shown) through a. Thereby, the rotation of the operation lever 52 is locked, and the set position of the developing unit 8 is securely held.

To release the set position of the developing unit 8, first, the toner container 15 is removed from the copier body in a known manner. Development housing 10
The toner supply port (not shown) of the toner container 15 connected to the toner supply port 15a (see FIG. 9) is automatically closed by a well-known shutter mechanism by the removal operation. Next, after unlocking the operation lever 52 with respect to the front side plate 18, the operation lever 52 is rotated counterclockwise in FIG. Each of the cams 40 has a gear 5
It is rotated clockwise integrally with the shaft 32 via 4 and 50, and is positioned in a non-operation position separated downward from the bottom surface (see FIG. 2). Stoppers 56 are provided on the front side plate 18 and the rear side plate 19, and each of the stoppers 56 is configured to abut on the case member 36 of the corresponding cam 40 to prevent clockwise rotation at a predetermined position. ing. Each of the cams 40 is positioned substantially horizontally, and a control lever 52
Are located at approximately 45 ° angular positions. The developing unit 8 moves downward along with the rail unit 20 by its own weight in a counterclockwise direction from the operation position shown in FIG. 1 to the non-operation position shown in FIG. Is rotated around the axis O (the axis L). Since the developing unit 8 is rotated around the common axis L together with the rail unit 20, the rotation is smoothly and reliably performed. The restraint of the developing unit 8 to the inoperative position is surely performed by the rotation restricting means described above. Next, by pulling the developing unit 8 forward with respect to the rail unit 20, the locked pin portion 15 b of the projecting wall 15 of the developing housing 10 is formed on the front shaft portion 24 of the front supported wall 22 of the rail unit 20. Support hole 24a
Each of the positioning locked pin portions 17b formed at the rear end of the developing housing 10 is separated from the locking hole 23b formed in the base wall portion 23a of the rear supported wall 23 of the rail unit 20. We are separated from each other. By the withdrawal,
The developing housing 10 of the developing unit 8 has the structure described above.
The bottom surface of the developing housing 10 and the bottom wall 2 of the rail body 21
Due to the clearance formed between the rail 1 and the upper surface of the rail 1a, the rail is relatively slightly dropped in the guide groove of the rail main body 21 to facilitate sliding. The developing unit 8 is easily pulled out from the rail unit 20. Rail unit 2
The movement toward zero is prevented by each of the long holes 22b formed in the front supported wall 22 interfering with the head of the rotation restricting pin 26 mounted on the front side plate 18 (rotation). The head of the restriction pin 26 is formed to have a larger diameter than the width of the corresponding elongated hole 22b).

When the developing unit 8 is rotated from the non-operating position to the operating position (set position), first, the developing unit 8 is fitted and mounted on the rail unit 20 as described above. Next, the operation lever 52 is
Is rotated clockwise. Each of the cams 40 is rotated counterclockwise from the non-operating position to the operating position integrally with the shaft 32 via the gears 54 and 50. The above bottom surface of the developing housing 10 corresponds to the cam 4 through each of the through holes 21 e (see FIG. 7) of the rail unit 20.
Directly pushed up by 0. The developing unit 8 is rotated clockwise upward together with the rail unit 20 around the common axis L, and is positioned at an operating position where the developing roller 12 is brought into contact with the surface of the photosensitive drum 2 (FIG. 1). The developing roller 12 is a photosensitive drum 2
Is pressed almost toward the axis of the photosensitive drum 2 at the lowermost position of the surface of the photosensitive drum 2. Since the developing unit 8 is rotated around the common axis L together with the rail unit 20, the rotation is smoothly and reliably performed, and the positioning of the developing unit 8 with respect to the photosensitive drum 2 is smoothly and reliably performed. Also, each of the cams 40 pushes the developing housing 10 upward while each of the cams 40 abuts against the bottom surface of the developing housing 10 and moves relative to the bottom surface radially outward from the axis L. It is configured to be able to rotate from the non-working position to the working position,
As described above, when each of the cams 40 is rotated from the non-operating position to the operating position, the bottom surface of the developing housing 10 is pushed up by each of the cams 40, and the developing unit 8 and the rail unit 20 are rotated around the axis L. Since the cam 40 is configured to be rotated upward from the non-operation position and positioned at the operation position, the upward movement of the developing unit 8 (and the rail unit 20) by each of the cams 40 is easy and smooth. And the developing unit 8
The positioning operation with respect to the photosensitive drum 2 is easily, smoothly and reliably performed. Next, the operation lever 52 is locked to the front side plate 18 as described above. Thereafter, the toner container 15 is mounted on the copier body in a known manner. The toner supply port (not shown) of the toner container 15 is automatically opened by a well-known shutter mechanism by the mounting operation, and is connected to the toner supply port 15a of the developing housing 10 (see FIG. 9). The above-described developing unit support mechanism according to the present invention, in addition to the above-described effects, further has a simple overall configuration and enables cost reduction.

[0027]

According to the developing unit support mechanism of the present invention, the operation of positioning the developing unit with respect to the photosensitive drum and the operation of releasing the set position can be easily and reliably performed. Further, it is possible to easily secure the positioning accuracy of the developing unit with respect to the photosensitive drum as desired. Furthermore, the overall configuration is simple, which enables cost reduction.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a main part of a copying machine having an embodiment of a developing unit support mechanism according to the present invention.

FIG. 2 is a configuration diagram showing another operation mode of the support mechanism of the developing unit shown in FIG.

FIG. 3 is a schematic side view of a more specific embodiment of the support mechanism of the developing unit shown in FIG. 1 as viewed from the front side of the copying machine main body.

FIG. 4 is a schematic sectional view taken along the line AA of FIG. 3;

FIG. 5 is an exploded schematic perspective view of the developing unit and the rail unit shown in FIG.

FIG. 6 is a sectional view taken along the line BB of FIG. 3;

FIG. 7 is a perspective view of the rail unit shown in FIG. 3;

FIG. 8 is a perspective view of the rail unit shown in FIG. 7 viewed from another direction.

FIG. 9 is a perspective view of the developing unit shown in FIG. 3;

FIG. 10 is a schematic perspective view of a cam unit provided in a support mechanism of the developing unit shown in FIG.

FIG. 11 is an enlarged schematic perspective view showing a part of a cam mechanism included in the cam means shown in FIG. 10;

FIG. 12 is a front reduced view of the cam mechanism shown in FIG. 11;

[Explanation of symbols]

 2 Photosensitive drum 8 Developing unit 10 Developing housing 12 Developing roller 20 Rail unit 40 Cam

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H071 BA03 BA13 BA14 BA16 BA19 BA29 DA08 EA04 EA06 2H077 BA07 BA08 BA09 GA04

Claims (11)

[Claims] A rail unit rotatably supported about an axis parallel to the drum, a developing housing, and a frame unit provided in an image forming machine including a photosensitive drum. A developing unit that includes a developing roller and is supported by being fitted to the rail unit so as to be detachable in the axial direction from one end thereof, and a developing unit,
A developing device comprising a cam means capable of selectively moving an operating position in which the developing roller is brought into contact with the surface of the drum and a non-operating position in which the developing roller is spaced substantially downward from the surface of the drum; In the unit support mechanism, a shaft portion is formed at one end and the other end of the rail unit so as to be rotatably supported on the frame means around the axis,
At one end of the developing housing, a supported portion is formed, which is coaxially supported by being axially detachably fitted to a shaft formed at one end of the rail unit, and is supported at the other end of the rail unit. Positioning means for locking the other end of the developing housing to the other end of the rail unit so as to be detachable in the axial direction is provided between the developing unit and the other end of the developing housing. When being moved toward the other end, the supported portion at one end of the developing housing is fitted and supported by the shaft portion at one end of the rail unit, and the other end of the developing housing is connected to the other end of the rail unit. A support mechanism for the developing unit, wherein the supporting mechanism is fixed to an end portion via a positioning means, is mounted on the rail unit, and can rotate around the common axis together with the rail unit. 2. A coaxial support hole is formed at a shaft portion formed at one end of the rail unit, and a supported portion formed at one end of the developing housing is engaged with the support hole. The positioning means includes a locking pin formed at the other end of the rail unit, and a positioning cover formed at the other end of the developing housing and capable of being detachably locked to the locking hole. The support mechanism of the developing unit according to claim 1, further comprising a locking pin portion. 3. The position of the axis of the developing unit mounted on the rail unit is defined such that the developing unit can be rotated downward by its own weight together with the rail unit from an operation position to a non-operation position according to the action of the cam means. The support mechanism of the developing unit according to claim 1, wherein: 4. The cam means includes a cam which can be selectively rotated between an operation position in which the bottom surface of the developing housing is directly pressed and pushed upward, and a non-operation position which is separated downward from the bottom surface. The cam is moved from the non-operation position to the operation position so that the cam abuts on the bottom surface of the developing housing and moves relative to the bottom surface in the radially outward direction from the axis L to push the developing housing upward. When the cam is rotated from the non-operating position to the operating position, the bottom surface of the developing housing is pushed up by the cam, and the developing unit moves upward with the rail unit around the axis from the non-operating position. The support mechanism of the developing unit according to claim 3, wherein the support mechanism is rotated to move toward the operation position. 5. The cam means comprises: a shaft supported by the frame means so as to be rotatable about an axis parallel to the axis of the photosensitive drum; a case member disposed at both ends of the shaft; A cam mounted on each via spring means, each of the cams being biased radially outwardly of the shaft by the spring means, each of the cams being positioned in an operative position, 5. The support mechanism according to claim 4, wherein each of the cams elastically presses a bottom surface of the developing housing. 6. The rail unit includes a flat plate-shaped rail body extending linearly in the axial direction with a predetermined width, and one end in the width direction at both longitudinal ends of the rail body. A through hole is formed at one end on the photosensitive drum side, and a part of the bottom surface of the developing housing is exposed downward through each of the through holes of the rail unit when the developing unit is mounted on the rail unit. And wherein each of said cams presses directly against a corresponding bottom surface of the developer housing through a corresponding through hole of the rail unit when each of said cams is pivoted toward an operative position.
The support mechanism of the developing unit according to the above. 7. The frame means comprises a pair of side plates arranged at intervals in the axial direction, each of the side plates is formed with a support hole having an axis common to the axis, and the rail unit comprises: A flat plate-shaped rail body extending linearly in the axial direction with a predetermined width, and one end in the width direction at both ends in the longitudinal direction of the rail body, from one end opposite to the photosensitive drum. And a supported wall that stands upright at an outwardly extending position and is opposed to each other at a distance from each other, wherein each of the supported walls has the shaft portion in the axial direction from each of the supported walls. It is formed so as to extend from one end of the rail unit toward the other end, and the shaft portion of the supported wall at one end of the rail unit is inserted into the support hole of one of the side plates and the other end of the rail unit is covered with the shaft. The shaft on the support wall is The rail unit is rotatably supported by each of the side plates by being detachably and rotatably inserted into the support holes of the side plates, respectively. 3. The support mechanism of the developing unit according to 1. 8. A rotation restricting means for restricting the rotation of the rail unit between the rail unit and one of the side plates so that the developing unit rotates from the operating position and stops at the non-operating position. The support mechanism of the developing unit according to claim 7, wherein is provided. 9. The rotation restricting means is provided on one side plate.
At least one mounting hole formed at a position radially outward from the support hole, and an axial center of the shaft formed at one of the supported walls of the rail unit at a position radially outward from the shaft. At least one elongated hole extending in a tangential direction or a circumferential direction of an imaginary circle centered at the center, and a rotation restricting pin fixed to the mounting hole through the elongated hole, and the developing unit operates together with the rail unit. In this state, one longitudinal end surface of the long hole of the rail unit is positioned with a gap with respect to the outer peripheral surface of the rotation regulating pin of one of the side plates, and the developing roller is moved from the surface of the photosensitive drum. When the developing unit is rotated about the axis integrally with the rail unit in a direction in which the developing unit is substantially separated downward, the one end surface of the elongated hole of the rail unit in the longitudinal direction becomes the outer peripheral surface of the rotation regulating pin. The pivoting of the rail unit is allowed to contact is restricted, the developing unit is positioned at the inoperative position with the rail unit, the support mechanism of the developing unit according to claim 8. 10. A supporting hole having an axis common to the axis is formed in the shaft of one of the supported walls of the rail unit, and one end in the longitudinal direction of the developing housing is provided at one end in the width direction of the developing housing. A protruding wall extending to the opposite side to the photoreceptor drum, and a locked pin portion extending in the axial direction from one end of the developing housing to the other end is formed on the protruding wall. When the developing unit is fitted to the rail unit and moved from one end to the other end, the locked pin portion is disengaged from a support hole formed in the shaft portion of one of the supported walls of the rail unit. The support mechanism of the developing unit according to claim 7, which is freely fitted. 11. The other supported wall of the rail unit has at least one locking hole extending in the axial direction, and the other end of the developing housing in the longitudinal direction has the same axial direction. At least one positioning locked pin portion extending from one end of the developing housing toward the other end is formed, and when the developing unit is fitted to the rail unit and moved from one end to the other end, 8. The positioning locked pin portion is detachably locked in the locking hole.
A support mechanism for a developing unit according to claim 10.