JPH1063167A - Image forming machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the fitting of a photoreceptor unit to a machine frame by making both end parts of the supporting shaft of a photoreceptor drum possible to be positioned in the upper parts of pivotally supporting parts provided in the machine frame, when parts to be guided provided in the photoreceptor unit are abutted on guiding parts provided in a fixing unit. SOLUTION: First, the parts to be guided 411a provided in a pair of sidewall members constituting the photoreceptor supporting means of the photoreceptor unit are abutted on the guiding parts 601c which are provided in both end parts of a fixing housing 601 constituting the fixing unit 60, respectively. Thus, in a state where the parts to be guided 411a are abutted on the guiding parts 601c, both end parts of the supporting shaft of the photoreceptor drum 42 are positioned in the pivotally supporting parts provided on the front and rear sidewalls constituting the machine frame 3 respectively and guiding groove parts 351 constituting the pivotally supporting parts. When a process unit is lowered, both end parts of the supporting shaft of the drum 42 are guided to the guiding groove parts 351 of the pivotally supporting parts, to be fitted into fitting grooves 352.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention develops an electrostatic latent image formed on a photosensitive layer of a photosensitive drum such as an electrostatic copying machine or a laser printer into a toner image and transfers the toner image to a transfer paper. The present invention relates to an image forming machine.

[0002]

2. Description of the Related Art An image forming machine of this type is provided rotatably and sequentially passes through a charging area, an electrostatic latent image forming area, a developing area and a transfer area. A charger for charging the peripheral surface of the photosensitive drum to a specific polarity; and a developing device disposed in the developing area and developing the electrostatic latent image formed on the peripheral surface of the photosensitive drum in the electrostatic latent image forming area into a toner image. The image forming apparatus includes an apparatus and a fixing unit that is provided in the transfer area and transfers a toner image formed on the peripheral surface of the photosensitive drum to transfer paper. In an image forming apparatus of this type, the photosensitive drum is constituted by a photosensitive member supporting means for rotatably supporting the photosensitive drum in order to easily replace the photosensitive drum. It is configured to be detachably attached to the body frame from above.

[0003]

In an image forming machine in which the photosensitive unit is removably mounted on the machine frame from above as described above, both ends of the support shaft of the photosensitive drum are provided on the machine frame. Are provided, and when the photoconductor unit is mounted on the body frame, both ends of the support shaft are positioned above the shaft support section, and the photoconductor unit is mounted on the body frame. I try to put it down. However, in the case where the photoconductor unit and the fixing unit are laid out close to each other in order to make the image forming machine compact, when the photoconductor unit is lowered onto the machine frame from above,
There is a problem that the photoreceptor unit interferes with the fixing unit and deteriorates its mounting property.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a main technical problem thereof is that an image forming apparatus capable of easily mounting the photosensitive member unit when the photosensitive unit is mounted on a body frame. And a photoreceptor unit of the image forming machine.

[0005]

According to the present invention, there is provided a photoreceptor unit including a photoreceptor drum and a photoreceptor supporting means for supporting a support shaft of the photoreceptor drum. An image forming apparatus having a fixing unit including a fixing roller pair and a fixing housing accommodating the fixing roller pair on the downstream side of the photoconductor unit in the transfer paper transport direction. At
The machine frame is provided with shaft support portions for supporting both end portions of the support shaft of the photoconductor drum, and the photoconductor support means has a guided portion at a lower portion facing the fixing unit. The fixing unit is provided with a guide portion for guiding the guided portion on a side surface facing the photoreceptor unit, and a fixing portion provided on the photoreceptor support means of the photoreceptor unit. When the guide portion is brought into contact with the guide portion provided on the fixing unit, both ends of the support shaft of the photosensitive drum are positioned above the shaft support portion provided on the body frame. An image forming apparatus is provided.

Further, according to the present invention, the shaft support portion provided on the body frame is formed so as to extend upward and is connected to a lower end of the guide groove portion which is formed upward and open. An image forming machine is provided which is constituted by a fitting groove formed and having a width corresponding to the diameter of the support shaft.

Further, according to the present invention, the photosensitive member supporting means includes a pair of side wall members for respectively supporting both ends of a support shaft of the photosensitive drum, and the pair of side wall members face the fixing unit. An image forming machine is provided, in which a guided portion is provided at a lower portion of an end surface of the image forming device.

Further, according to the present invention, there is provided a photosensitive drum and a photosensitive member supporting means for supporting a support shaft of the photosensitive drum, and from above a machine frame mounted on a machine housing provided with a fixing unit. A photoconductor unit of an image forming machine configured to be detachable, wherein the photoconductor support unit includes:
A guided portion is provided at a lower portion facing the fixing unit, and when a guided portion provided on the photoreceptor support means of the photoreceptor unit comes into contact with a guide portion provided on the fixing unit, A photoreceptor unit of an image forming machine is provided, wherein both end portions of a support shaft of the photoreceptor drum are positioned above a shaft support portion provided on the body frame.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image forming machine constructed according to the present invention will be described in detail with reference to the accompanying drawings. In the illustrated embodiment, a printer will be described as an example of an image forming apparatus configured according to the present invention.

FIG. 1 schematically shows an embodiment of a printer constructed according to the present invention. Printer 2
Is a small and low-speed laser printer used as a printing device such as a word processor in this embodiment, and includes a body housing 20 made of synthetic resin.
Is provided. The body housing 20 includes a box-shaped housing main body 21 whose upper part is open, and a cover 23 pivotally mounted on a shaft 22 provided on the upper part of the housing main body 21. The body frame 3 is disposed on the housing body 21 of the body housing 20 configured as described above. The process unit 4 is detachably mounted on the machine frame 3.

As shown in FIG. 2, the process unit 4 includes a photosensitive unit 40 and a developing unit 50 swingably supported by the photosensitive unit 40 via a support shaft 5.
And The photoreceptor unit 40 includes a photoreceptor support means 41. The photoreceptor support means 41 is provided with a pair of side wall members 411 spaced apart in the front-rear direction as shown in FIG. (Only one side wall member is shown), and connecting members 412a and 412b connecting the lower portions of the pair of side wall members 411. In the drawing of the pair of side wall members 411, guided portions 411a which are substantially perpendicular to each other are provided below a transfer unit side end surface described later. The connecting members 412a and 412b are arranged such that inner surfaces facing each other are parallel to each other, and form a charging means mounting space 412c between which the charging means described later is disposed. As shown in FIG. 5, the connecting members 412a and 412b do not have the front end (the right side in FIG. 7) reaching the side wall member 411 on the front side. 411 is connected by the side connection member 412d. The charging means mounting space 412c is located to face a charging area described later. The photoconductor supporting means 41 thus configured is integrally formed of a synthetic resin. Support portions 413 each having a mounting hole 414 are provided at the upper end of the pair of side wall members 411 constituting the photosensitive member support means 41 on the developing unit 50 side.
By inserting a support shaft 5 made of a metal bar disposed in a later-described developing housing of the developing unit 50 into a mounting hole 414 provided in the supporting portion 413, the photosensitive unit 40 and the developing unit 50 can be connected to each other. Is swingably supported.

The photoreceptor unit 40 includes a photoreceptor drum 42 having a photosensitive layer formed on a peripheral surface. Hereinafter, the structure of the photosensitive drum 42 and the support structure of the photosensitive drum 42 will be described with reference to FIG. In the illustrated embodiment, the photosensitive drum 42 has a photosensitive layer mounted on the peripheral surface of an aluminum cylinder, and is rotatably supported by a support shaft 43 in a state where axial movement is restricted at a predetermined position. ing. A driven gear 70 is mounted on one end (right end in FIG. 7) of the photosensitive drum 42. The driven gear 70 is made of a conductive synthetic resin,
The mounting portion 701 includes a helical gear 702 and a shaft insertion hole 703. The mounting portion 701 is press-fitted into one end of the photosensitive drum 42. The helical gear 702 is formed in an inclined direction such that a thrust generated during driving acts on the other end. A flange 71 is attached to the other end (left end in FIG. 7) of the photosensitive drum 42. The flange 71 is made of a conductive synthetic resin, and has a mounting portion 711, a locking claw portion 712, and a shaft insertion hole 713.
The mounting portion 711 is pressed into the other end of the photosensitive drum 42. The driven gear 70 attached to both ends of the photosensitive drum 42 thus configured
The support shaft 420 is inserted through the shaft insertion holes 703 and 713 provided in the flange 71. This support shaft 420
An annular groove 421 is provided at a predetermined position, and the locking claw portion 712 of the flange 71 is engaged with the annular groove 421. Therefore, the photosensitive drum 42 is rotatably supported by the support shaft 420 in a state where the movement in the axial direction is restricted at a predetermined position. Thus, the photosensitive drum 4
The support shaft 420 supporting the support member 2 is supported by a pair of side wall members 411 constituting the photoconductor support means 41 so as to be slidable in the axial direction. The end face of the flange 71 attached to the other end of the photosensitive drum 42 and the side wall member 411
A packing 72 made of felt or the like is provided between the photosensitive drum 42 and the end face of the driven gear 70 attached to one end of the photosensitive drum 42 to the side wall member 411 constituting the photosensitive member supporting means 41. They are in contact. As described above, the driven gear 70 attached to one end of the photosensitive drum 42 by the packing 72 is assembled with the end face of the driven gear 70 in contact with the side wall member 411. They will be assembled in a positional relationship. The driven gear 70 is moved in a direction indicated by an arrow in FIG.
22, the electrostatic latent image forming area 423, the developing area 424, and the transfer area 425 are sequentially driven to rotate.

In the charging means mounting space 412c located in the charging area 422, a charging means 43 is provided, which is disposed to face the lower peripheral surface of the photosensitive drum 42.
The charging unit 43 includes a charging corona discharger 43 serving as a charger disposed along the axial direction in parallel with the photosensitive drum 42.
1 and a charger holding member 432 made of a synthetic resin for mounting and holding the charging corona discharger. The charger holding member 432 is fitted in the charging means mounting space 412c and positioned at a predetermined position. I have. The charging area 42
A foreign matter collecting brush 44 that is in contact with the peripheral surface of the photoconductor drum 42 is disposed between the photoconductor drum 42 and the transfer area 425 along the axial direction of the photoconductor drum 42. The paper dust collecting brush 44 is made of acrylic fiber or the like and has substantially the same length as the length of the photosensitive drum 42 in the axial direction. It is attached to a brush support member 440 disposed along the same. The upper end of the charger holding member 432 is formed between the charging corona discharger 431 disposed in the charging area 422 and the foreign matter collecting brush 44 so as to protrude so as to be close to the peripheral surface of the photosensitive drum 42. And forms a toner intrusion prevention wall 47. This toner intrusion prevention wall 47
When the residual toner adhered to the peripheral surface of the photosensitive drum 42 and removed by the foreign matter collecting brush 44 together with foreign matter such as paper dust falls without being reliably captured by the foreign matter collecting brush 44, the charging corona It has a function of preventing intrusion on the discharger 431.

The transfer paper fed from diagonally upper left in FIG. 2 is directed to a transfer area 425 on the peripheral surface of the photosensitive drum 42 between a pair of side wall members 411 constituting the photosensitive member support means 41. A lower guide plate 451 that constitutes one of the pre-transfer guide plate pair 45 that guides the lower guide plate 451 is provided, and the lower guide plate 451 is integrally formed with the pair of side wall members 411. A plurality of guide ribs 451a are integrally formed on the upper surface of the lower guide plate 451 at intervals in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 2). The lower guide plate 451 is also provided with a plurality of reinforcing ribs 45 on the lower surface at intervals in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 2).
1 b is integrally formed, and the reinforcing rib 451 b is configured to abut on the support shaft 5. Therefore,
Even if the lower guide plate 451 is pressed by the upper surface thereof and bends, the reinforcing ribs 451b abut on the support shaft 5 to prevent the lower guide plate 451 from bending. Also, the lower guide plate 451
Is a pair of side wall members 41 constituting the photoreceptor support means 41.
1 serves as a connecting member for connecting the upper portions to each other, and the rigidity of the photosensitive member supporting means 41 can be improved. Further, in the illustrated embodiment, since the lower guide plate 451 is integrally formed with the pair of side wall members 411, the positional relationship with respect to the photosensitive drum 42 rotatably supported by the pair of side wall members 411 can be determined with high precision. Can be maintained. Note that the lower guide plate 4 in the illustrated embodiment is used.
Numeral 51 functions as a member for preventing the photosensitive drum 42 from contacting the photosensitive layer when the process unit 4 is attached and detached, and also functions as a member for preventing the developing unit 50 from touching a later-described developing roller. It also has a function of preventing toner scattered from the surface of the roller from adhering to the transfer paper or the transfer path of the transfer paper.

A post-transfer guide plate 46 for guiding the transfer paper transferred in the transfer area 425 to a fixing means described later is disposed between the pair of side wall members 411 constituting the photosensitive member supporting means 41. The post-transfer guide plate 46 is formed integrally with the pair of side wall members 411. Therefore, the post-transfer guide plate 46 functions as a connecting member for connecting the pair of side wall members 411 constituting the photoconductor supporting unit 41 to each other, and can improve the rigidity of the photoconductor supporting unit 41. The post-transfer guide plate 4 in the illustrated embodiment.
6 can also function as a contact preventing member for the photosensitive layer of the photosensitive drum 42 when the process unit 4 is attached or detached.

Next, the developing unit 50 as an electrostatic latent image developing device will be described. The developing unit 50 in the illustrated embodiment includes a developing housing 51 in which a developer composed of one-component toner is stored. The developing housing 51 has a bottom wall 511, a front wall 512 a (see FIG. 3) formed upright from the front and rear ends of the bottom wall 511 (ends in a direction perpendicular to the paper surface in FIG. 2), and It comprises a rear side wall 512b and a left side wall 513,
These are integrally formed of a synthetic resin, and the
And the developing chamber 515. A stirring chamber 514 and a developing chamber 515 are provided on a bottom wall 511 of the developing housing 51.
And a partition wall 516 provided in the front-rear direction (the direction perpendicular to the paper surface in FIG. 2) is integrally formed. Both left and right sides of the partition wall 516 have an arc-shaped guide surface 516a.
And 516b. Development housing 51
A connecting member 517 is provided between the front and rear side walls 512, which is disposed above the developing chamber 515.
2 are integrally formed. A toner supply hole 518 is formed in the rear side wall 512 of the developing housing 51.
9 are fitted. The front and rear side walls 512 are provided at the upper end of the developing housing 51 on the side of the developing chamber 515 configured as described above.
The support shaft 5 is provided so as to pass through the support shaft 5, and provided at both ends of the support shaft 5 in the support portions 413 of the pair of side wall members 411 constituting the photoconductor support means 41 of the photoconductor unit 40. By fitting the mounting holes 414, the photoconductor unit 40 and the developing unit 50 are supported so as to be able to swing each other. A coil spring 5 serving as a spring means is provided between the lower end of the photoconductor support means 41 of the photoconductor unit 40 and the lower end of the developing housing 51.
The photosensitive member supporting means 41 and the developing housing 51 are urged by the coil spring 52 so as to be attracted to each other with the support shaft 5 as a fulcrum. The developing housing 51 is open above and to the right, that is, on the photoconductor unit 40 side.

In the developing housing 51, a developing roller 53, a supply roller 54, a stirring means 55 and a developer regulating means 56 are provided. The developing roller 53 is
A rotating shaft 531 provided in the developing chamber 515 of the developing housing 51 and rotatably mounted on the front and rear side walls 512 constituting the developing housing 51, and a solid synthetic rubber roller fixed to the outer peripheral surface of the rotating shaft 531 532. The rotating shaft 531 can be formed from an appropriate metal material such as stainless steel. Solid synthetic rubber roller 53
2 is made of a relatively flexible and conductive material, for example, a conductive solid synthetic rubber such as urethane rubber. In the illustrated embodiment, a solid synthetic rubber roller 5 is used.
The surface roughness of the peripheral surface of No. 32, that is, the ten-point average roughness Rz specified in JIS B 0601 is set to 5.0 to 12.0. The volume resistance of the solid synthetic rubber roller 532 is set to about 10 ⁴ to 10 ⁹ Ω · cm. The roller hardness of the solid synthetic rubber roller 532 is set to 60 to 80 in Asker C hardness in the illustrated embodiment. The roller 532 of the developing roller 53 configured as described above is exposed through a right opening formed in the developing housing 51, and is exposed to the photosensitive drum 42.
Is positioned opposite to. The peripheral surface of the roller 532 constituting the developing roller 53 is pressed against the peripheral surface of the photosensitive drum 42 in the developing region, and the peripheral surface of the roller 532 is slightly elastically compressed at the pressed nip. ing. Rotating shaft 53 of developing roller 53
1 is a developing housing 51 as shown in FIG.
The driven gear 501 is mounted on the end of the roller 532, and is driven by a driving gear to be described later in a direction indicated by an arrow in FIG.
In the developing area, which is a contact portion between the photosensitive drum 42 and the photosensitive drum 42, the photosensitive drum 42 is driven to rotate upward from the lower side. In addition,
The driven gear 501 is formed by a helical gear. A transmission spur gear 502 is integrally formed inside the driven gear 501. The rotation of the rotation shaft 531 also drives the roller 532 to rotate in the direction shown by the arrow, and the peripheral surface of the roller 532
3. The developer regulating area 534 and the developing area 424 are sequentially moved. In the illustrated embodiment, a constant voltage of 300 V is applied to the rotating shaft 531 of the developing roller 53.

The replenishing roller 54 is disposed in the developing chamber 515 of the developing housing 51 in parallel with the developing roller 53, and is rotatably mounted on the front and rear side walls 512 constituting the developing housing 51. A shaft 541;
And a roller 542 fixed to the outer peripheral surface of the rotating shaft 541. The rotating shaft 541 can be formed of an appropriate metal material such as stainless steel, similarly to the rotating shaft 531 of the developing roller 53. The roller 542 is made of foam such as foamed silicone or foamed urethane. The roller 542 is a roller 5 of the developing roller 53 in a developer holding region 533 which is a nip portion with the developing roller 53
32. Roller 54 of supply roller 54
The hardness of the foam constituting the developing roller 2 is considerably smaller than the hardness of the roller 532 constituting the developing roller 53 (for example, about 35 in Asker C hardness), and the roller 542 is pressed against the roller 532 of the developing roller 53. It is desirable that the roller 542 be elastically compressed by about 0.1 to 0.6 mm in the nip area. Roller 5
42 also has conductivity, and its volume resistance is 10 ² to 1
It is set to about 0 ⁶ Ω · cm. As shown in FIG. 3, a front end of the rotation shaft 541 of the supply roller 54 projects from the front wall 512a of the developing housing 51, and a driven gear 503 is mounted on this end. The gear 503 is configured to mesh with the transmission spur gear 502. Accordingly, the rotation shaft 541 of the supply roller 54 is moved in the direction indicated by the arrow in FIG.
In the developing area, which is the contact portion between the photoconductor drum 2 and the photosensitive drum 42, the photoconductor drum 42 is driven to rotate upward from below. The direction indicated by the arrow by the driving means (not shown),
In the developer holding area 533 which is a nip portion between the roller 42 and the roller 532 of the developing roller 53, the developer is rotated from the upper side to the lower side. By the rotation of the rotating shaft 541, the roller 542 is also driven to rotate in the direction shown by the arrow.
In the illustrated embodiment, a constant voltage of 450 V higher than the voltage applied to the developing roller 53 is applied to the rotation shaft 541 of the supply roller 54.

The peripheral speed V1 of the photosensitive drum 42, the peripheral speed V2 of the developing roller 53, and the peripheral speed V3 of the replenishing roller 54 are set in a relationship of V1 <V2 <V3.
In the illustrated embodiment, the relationship between the peripheral speed V1 of the photosensitive drum 42 and the peripheral speed V2 of the developing roller 53 is as follows.
1.2V1 ≦ V2 ≦ 2.5V1, the peripheral speed V2 of the developing roller 53 and the peripheral speed V3 of the replenishment roller 54 are set.
Is set to be 1.0V2 ≦ V3 ≦ 2.0V2. When the peripheral speed V2 of the developing roller 53 becomes 1.2 V1 or less, the supply of the developer to the photosensitive drum 42 becomes insufficient, and the image density is reduced. When the peripheral speed V2 of the developing roller 53 becomes 1.2 V1 or less, the scraping action of the developing roller 53 against the non-transferred developer attached to the photosensitive drum 42 after the transfer is reduced. This causes a so-called offset fog to occur because the photoreceptor drum 42 cannot be removed. On the other hand, when the peripheral speed V2 of the developing roller 53 becomes 2.5 V1 or more, the driving torque of the developing roller 53 increases, and the developer is scattered by centrifugal force. Further, when the peripheral speed V3 of the supply roller 54 becomes 1.0 V2 or less, the supply of the developer to the developing roller 53 becomes insufficient, which causes a decrease in image density. Also, the peripheral speed V of the supply roller 54
When 3 is 1.0 V2 or less, the action of scraping the peripheral surface of the developing roller 53 by the replenishing roller 54 is weak. Therefore, if the non-transferred developer adhered to the photosensitive drum 42 adheres to the developing roller 53 after the transfer, It becomes difficult to remove the adhered developer, and the adhered developer causes a so-called ghost phenomenon that appears during the next development. On the other hand, when the peripheral speed V3 of the supply roller 54 becomes 2.0 V2 or more, the supply roller 54
, The developer tends to stay above the nip portion between the supply roller 54 and the developing roller 53, which causes a shortage of the developer supply to the developing roller 53.

In the stirring chamber 514 of the developing housing 51, a stirring means 55 is provided. The stirring means 55
A rotating shaft 551 rotatably mounted on the front and rear side walls 512 constituting the developing housing 51, a stirring member 552 fixed to the rotating shaft 551, and An elastic stirring sheet member 553 attached to the stirring member 552 is included.
The stirring member 552 is formed of a synthetic resin,
A plurality of openings are provided in a longitudinal direction (a direction perpendicular to the paper surface in FIG. 2). The stirring sheet member 553 is made of, for example, polyethylene terephthalate (PET) having flexibility and elasticity.
P) It is formed of resin, and is fixed to the edge of the tip of the stirring member 552 by an adhesive or the like. As shown in FIG. 3, the end of the agitating means 55 having the above-described configuration is provided so as to protrude from the front side wall 512a of the developing housing 51, and the driven gear 504 is attached to the end. I have. The driven spur gear 504 is a driven spur gear 503 mounted on the rotation shaft 541 of the supply roller 54.
And transmission gears 505, 506 and 507 rotatably mounted on the front side wall 512a of the developing housing 51. Accordingly, the stirring means 55 is continuously driven to rotate in the direction indicated by the arrow in FIG.

The developer regulating means 56 includes a flexible elastic blade 561 pressed against the peripheral surface of the roller 532 constituting the developing roller 32.
The blade 561 has a thickness of, for example, 0.1 to 0.2 mm.
The length of the roller 532 constituting the developing roller 53 is substantially the same as the length in the longitudinal direction. Blade 561
Is a bottom wall 5 whose base end constitutes the developing housing 51.
11 is attached to the blade mounting portion 511a provided at the open end of the photoconductor unit 40 side. That is, the blade 561
The base end of the blade mounting portion 511a and the holding plate 562
And fixed by screws 563. The distal end of the blade 561 is bent, and the bent portion is configured to be pressed against the peripheral surface of the roller 532 constituting the developing roller 53 in the developer regulating region 534.

The developing housing 51 is provided with a lid 57 for covering the opened upper part. The lid 57 is made of a synthetic resin, and is fixed to an upper surface of the front and rear side walls 512, the left side wall 513, and the upper surface of the connecting member 517 constituting the developing housing 51 by an adhesive. A regulating portion 571 that extends in the front-rear direction (a direction perpendicular to the paper surface in FIG. 2) and protrudes toward the developing chamber 515 is integrally formed on the inner surface of the lid 57 at a position facing the supply roller 54. A predetermined interval is provided between the lower end of the regulating portion 571 and the outer peripheral surface of the roller 542 constituting the supply roller 54. In the illustrated embodiment, a sheet-shaped seal member 58 is attached to the connecting member 517 constituting the developing housing 51. The sheet-shaped sealing member 58 is made of, for example, polyethylene terephthalate (P
It is made of a sheet member having flexibility and elasticity, such as ETP) resin, and has substantially the same length as the axial length of the roller 532 constituting the developing roller 53. One end of the sheet-shaped sealing member 58 is connected to the connecting member 517.
Is fixed to the developing roller 53 by a fixing means such as an adhesive.
2 is elastically brought into contact with the peripheral surface. The sheet-shaped sealing member 58 thus configured is provided together with the blade 561 of the developer regulating means 56 on the developing housing 5.
The developer is prevented from scattering from the opening on the side of the photoconductor unit 40.

The process unit 4 configured as described above is detachably mounted on the body frame 3 provided on the housing body 21 of the body housing 20 as shown in FIG. The body frame 3 will be described later in detail. A fixing unit 60 is disposed on the housing body 21 of the machine housing 20 on the downstream side (the right side in FIG. 1) of the process unit 4 in the transfer paper transport direction. The fixing unit 60 includes a fixing housing 60 disposed in a front-rear direction of the housing main body 21 (a direction perpendicular to the plane of FIG. 1) and parallel to the process unit 4.
1 is provided. The fixing housing 601 has a transfer paper introduction opening 601a on the process unit 4 side (upstream side in the transfer paper transport direction), and a transfer paper discharge opening 601b on the downstream side in the transfer paper transport direction. As shown in FIG. 5, a pair of side wall members 411 constituting the photoconductor support means 41 are provided at both ends of the side surface of the fixing housing 601 facing the photoconductor unit 40.
Are provided with guide portions 601c formed substantially vertically corresponding to the guided portions 411a provided respectively. Note that a plurality of openings 601d for releasing residual heat inside the fixing housing 601 are provided on the upper surface of the fixing housing 601. In the fixing housing 601 thus configured, a pair of fixing rollers 602 is disposed so as to face the transfer paper introduction opening 601a, and a pair of discharge rollers 603 is opposed to the transfer paper discharge opening 601b. It is arranged. The fixing roller pair 602 and the discharge roller pair 6
Numeral 03 is driven to rotate in a direction indicated by an arrow in FIG. In the transfer housing 601, a fixing roller pair 602 and a discharge roller pair 6 are provided.
The transfer paper guide plate pair 604 is disposed between the transfer paper guide plate 03 and the transfer paper guide plate 604.
A discharge tray 61 is provided downstream of the transfer unit 60 configured as described above in the transfer sheet transport direction.

Next, the machine frame 3 on which the process unit 4 is detachably mounted will be described with reference to FIGS. 1, 6, and 7. FIG. The body frame 3 is disposed on the housing body 21 of the body housing 20 at a position where the process unit 4 is provided. The body frame 3 is formed of a synthetic resin, and includes a bottom wall 31, a front side wall 32, and a rear side wall 33 as shown in FIG. One shaft support portion 34 for supporting one end of the support shaft 420 of the photosensitive drum 42 is provided on the front side wall 32 of the body frame 3, and the other end of the support shaft 420 is provided on the back side wall 33. Shaft supporting portion 35 for supporting
Is provided. One of the shaft support portions 34 provided on the front side wall 32 of the body frame 3 is formed so as to be connected to the guide groove 341 that is formed so as to extend upward and is open or open, and the lower end of the guide groove 341. A fitting groove 342 having a width corresponding to the diameter of the support shaft 420 is provided.
A guide surface 341a that slopes inward from the upper end is formed on the outer wall that forms the guide groove 341.
The fitting groove 342 is provided with a pressing member 343 formed by bending a conductive plate material such as a spring steel plate or a stainless steel plate. The pressing member 343 is connected to the photosensitive drum 42
Function as a ground for the metal plate 34.
4 is attached to the front side wall 32. The lower end of the metal plate 344 is connected to a frame base 345 made of a metal plate mounted on the bottom wall 31 constituting the body frame 3, and accordingly, the photosensitive drum 42
Is a driven gear 44 and a flange 45 made of a conductive synthetic resin, a support shaft 420 made of a metal bar,
43, body earthed to the frame base 345 via the metal plate 344. The rear side wall 33 of the body frame 3
The other shaft supporting portion 35 provided at the front side wall 3
A guide groove 351 that is provided to face the one shaft support portion 34 provided on the second member 2, and that is formed to extend upward similarly to the shaft support portion 34 and is open at the top; And a fitting groove 352 having a width corresponding to the diameter of the support shaft 420 and connected to the lower end of the support shaft 420.
A guide surface 351a inclined inward from the upper end is formed on an outer wall constituting the guide groove 351. The outer wall constituting the fitting groove 352 is continuous from a lower end of the guide surface 351a. Bearing portion 352a formed as
Function as

A driven gear 70 mounted on one end of the photosensitive drum 42 when the support shaft 420 of the photosensitive drum 42 is mounted on the shaft support portions 34 and 35 on the front side wall 32 of the body frame 3. Drive gear 3 that meshes with
6 are provided. A drive gear 37 that meshes with a driven gear 501 mounted on the rotation shaft 531 of the developing roller 53 is provided on the front side wall 32 of the body frame 3. The drive gear 36 and the drive gear 37 are formed by helical gears. In addition,
The driving gear 36 and the driving gear 37 are configured to be driven by a driving force of an electric motor (not shown) via an appropriate gear transmission mechanism.

The process unit 4 is mounted on the machine frame 3 configured as described above as follows. That is,
Cover 23 Constituting Body Housing 20 of Printer 2
1 is rotated counterclockwise in FIG. 1 around the axis 22, thereby opening the upper part of the housing body 21 constituting the body housing 20 and exposing the body frame 3. Next, the process unit 4 is mounted on the body frame 3 from above. At this time, first, the guided portions 411a provided on the pair of side wall members 411 constituting the photoreceptor support means 41 of the photoreceptor unit 40 are connected to both ends of the fixing housing 601 which constitutes the fixing unit 60 as shown in FIG. In contact with the guide portions 601c provided respectively. In this manner, the support shaft 420 of the photosensitive drum 42 is kept in a state where the guided portion 411a is in contact with the guide portion 601c.
Are positioned on the guide grooves 341 and 351 forming the shaft support 34 and the shaft support 35 provided on the front side wall 32 and the rear side wall 33 constituting the body frame 3 respectively. When the process unit 4 is lowered, both ends of the support shaft 43 of the photosensitive drum 42 are guided by the guide grooves 341 and 351 of the shaft supports 34 and 35 and fitted into the fitting grooves 342 and 352. At this time, the driven gear 70 mounted on one end of the photosensitive drum 42 meshes with and engages with the driving gear 36, and the driven gear 501 mounted on the rotating shaft 531 of the developing roller 53.
Are engaged with the driving gear 37. Then, the support shaft 421 of the photoconductor drum 42 is maintained in a state in which one end is in contact with the pressing member 343 and is pressed leftward, and the other end is in contact with the shaft contact portion 352a, as shown in FIG. Is done.
Therefore, the photosensitive drum 42 rotatably supported by the support shaft 421 in a state where the axial movement is restricted at a predetermined position,
It is securely mounted at a predetermined position on the body frame 3. For this reason, the photosensitive member support means 41 assembled to the support shaft 421 in a predetermined positional relationship with the photosensitive drum 42 is also reliably positioned at a predetermined position of the body frame 3. The machine frame 3 is provided with positioning means (not shown) for mounting the process unit 4 at a predetermined position with the photosensitive drum 42 positioned at a predetermined position. Reference numeral 4 is attached to a predetermined position of the body frame 3. Thus, the process unit 4
When mounting the fixing unit 60 on the body frame 3 from above, first, the guided units 411a provided on the pair of side wall members 411 constituting the photoconductor supporting means 41 of the photoconductor unit are attached to the fixing unit 60 as shown in FIG. The support shaft 4 of the photosensitive drum 42 is brought into contact with the guide portions 601 c provided at both ends of the fixing housing 601.
The front side wall 3 in which both ends of 20 constitute the body frame 3
2 and the guide grooves 341 and 35 forming the shaft support portion 35 and the shaft support portion 35 provided on the rear side wall 33, respectively.
Therefore, by lowering the process unit 4 thereafter, both ends of the support shaft 43 are guided by the guide grooves 341 and 351 of the shaft support portions 34 and 35, and are securely fitted into the fitting grooves 342 and 352. I can do it. Therefore, even when the photoconductor unit 40 and the fixing unit 60 are laid out at a position close to each other, the photoconductor unit 40 does not interfere with the fixing unit 60 when the process unit 4 is lowered onto the machine frame from above. Can be easily mounted. When the process unit 4 is mounted on the body frame 3 as described above, the upper part is closed by turning the cover 23 clockwise in FIG.

As shown in FIG. 1, a laser unit 63 is provided on the bottom wall 31 of the body frame 1 provided on the housing body 21 constituting the body housing 20 of the printer 2.
Are arranged. The laser unit 63 irradiates the photosensitive layer of the photosensitive drum 42 with a laser beam corresponding to print data from, for example, a word processor connected to the printer 2 in the electrostatic latent image forming area 423 of the process unit 4, Form a latent image.

In the cover 23 constituting the body housing 20 of the printer 2, a paper feed tray 64 on which transfer paper is placed is disposed at the upper left side in FIG. A paper feed roller 65 is provided downstream of the paper feed tray 64,
The paper feed roller 65 is driven to rotate in a direction indicated by an arrow in FIG. 1 by driving means (not shown). A friction pad 66 for separating sheets is disposed opposite the sheet supply roller 65. In addition, a non-contact type transfer roller 67 is provided in the transfer area 422 so as to face the photosensitive drum 42. The transfer roller 67 is formed of conductive urethane in the illustrated embodiment, and is rotatably supported by the cover 23. The transfer roller 67 is provided with collars (not shown) made of an insulating material such as a synthetic resin having an outer diameter larger than the transfer roller 67 at both ends thereof, and the collars are arranged in contact with the peripheral surface of the photosensitive drum 42. Accordingly, the transfer roller 67 is driven to slide while the photosensitive drum 42 rotates. The peripheral surface of the transfer roller 67 and the photosensitive drum 42
Is set to about 0.5 mm.
For example, 10
A constant current of μA is applied. An upper guide plate 45 constituting the other of the pre-transfer guide plate pair 45 is provided on the cover 23.
2 are provided.

The printer 2 in the illustrated embodiment is configured as described above, and its operation will be described below. Each of the above members starts to operate based on a print command from a word processor (not shown) or the like, and the charging corona discharger 4
3, the surface photosensitive layer of the photosensitive drum 42 is substantially uniformly charged to a specific polarity. Next, a laser beam corresponding to print data from a word processor or the like is emitted from the laser unit 24 to the charged surface of the photosensitive layer of the photosensitive drum 42, and an electrostatic latent image is formed. The electrostatic latent image thus formed on the photosensitive layer of the photosensitive drum 42 is developed into a toner image by the developing operation of the developing unit 50. The developing operation of the developing unit 50 is described below.
Details will be described later. On the other hand, the transfer paper placed on the paper feed tray 28 is fed one by one by the action of the paper feed roller 29 and the friction pad 30. Then, the transfer paper is guided by the pre-transfer guide plate pair 45 and the photosensitive drum 42 and the transfer roller 3.
1 and the toner image formed on the photosensitive drum 42 is transferred onto the surface thereof. The transfer paper onto which the toner image has been transferred is guided by the post-transfer guide plate 46, introduced into the fixing housing 601 from the transfer paper introduction opening 601a provided in the fixing housing 601 of the fixing unit 60, and conveyed to the fixing roller pair 602. Is done. The transfer paper on which the toner image has been heated and fixed by the action of the fixing roller pair 602 is transferred to the transfer paper discharge opening 601 by the discharge roller pair 603.
b is discharged onto the discharge tray 61. On the other hand, the transfer area 4
When the peripheral surface of the photosensitive drum 42 that has passed through the photosensitive drum 42 passes through the foreign matter collecting brush 44, foreign matter such as paper dust adhered to the peripheral surface is removed by the foreign matter collecting brush 44. At this time, the photosensitive drum 42 together with foreign matter such as paper dust
The residual toner adhering to the peripheral surface is also removed. The removed residual toner may fall without being reliably captured by the foreign matter collecting brush 44. If the dropped toner accumulates on the charging corona discharger 431, it causes charging unevenness. In the illustrated embodiment, however, the toner intrusion preventing wall 47 (470) prevents the charging corona discharger from dropping toner. 431 is prevented from entering.

Next, the developing operation of the developing unit 50 will be described. By starting the operation of the developing unit 50,
The developing roller 53, the supply roller 54, and the stirring means 5
5 are rotationally driven in directions indicated by arrows by drive means (not shown). Stirring member 55 constituting stirring means 55
2 and the stirring sheet member 553 rotate in the direction indicated by the arrow, the developer accommodated in the stirring chamber 514 passes over the partition wall 516 while being stirred, and
Is supplied into the developing chamber 514 from above. At this time, the regulating portion 571 formed on the inner surface of the lid 57 causes
The amount of the developer supplied into the developing chamber 514 is limited so as not to be excessive. The developer supplied by the agitating unit 55 in this manner rides on the roller 542 of the supply roller 54 and is transported to the nip portion which is the developer holding area 533 with the roller 532 of the developing roller 53. Since the supply roller 54 and the developing roller 53 rotate in the same direction from the upper side to the lower side in the developer holding area 533 which is a nip portion as described above, the supply roller 54 and the developing roller 53
The developer is sufficiently supplied to the developer, and the shortage of the developer can be prevented. The replenishing roller 54 and the developing roller 5
3 is a developer holding area 533 which is a nip portion as described above.
, The motor can be driven reliably without requiring a large driving force.

As described above, the developer transported to the developer holding area 533 which is a nip portion between the supply roller 54 and the developing roller 53 is applied to the roller 53 constituting the developing roller 53.
2 and is conveyed toward the developer regulating area 534. At this time, the supply roller 54 and the developing roller 53
Are rotated in the same direction from the upper side to the lower side in the developer holding area 533 which is the nip portion as described above, so that the developer is held by the developing roller 53 through both nip portions, and the developer is regulated. Since they are conveyed to the 534 and the developing zone 535, they are rubbed against each other when passing through the nip portion and are sufficiently charged, so that the occurrence of so-called fog is prevented.

In the developer regulating area 534, the blade 561 of the developer regulating means 56 acts on the developer retained on the peripheral surface of the roller 532 of the developing roller 53, and is retained on the peripheral surface of the roller 532. The developer is regulated to a required amount to form a thin layer. The developer regulated in the developer regulating area 534 by the blade 561 of the developer regulating means 56 and scraped off on the bottom wall 511 of the developing housing 51 is rotated by the supply roller 54 in the direction shown by the arrow. The partition wall 516 without stopping
Along the guide surface 516b.

As described above, the developer is held on the peripheral surface of the roller 532 constituting the developing roller 53 in the developer holding area 533, and is formed in a thin layer by the action of the blade 561 of the developer regulating means 56 in the developer regulating area 534. The urged developer is rotated in the direction of the arrow, and the developing area 424 is rotated.
Transported to In the development area 424, a developer is applied to the electrostatic latent image on the electrostatic photoconductor disposed on the peripheral surface of the photoconductor drum 42, and the electrostatic latent image is developed into a toner image. For example, an electrostatic latent image has a non-image area charged to about +600 V and an image area charged to about +120 V, and toner as a developer is attached to the image area (so-called reversal development). The photosensitive drum 42 and the developing roller 53 are driven to rotate in the direction indicated by the arrow in FIG. 2. Therefore, in the developing area 535, the peripheral surface of the photosensitive drum 42 and the roller
Both of them are moved from the lower side to the upper side in the same direction. The peripheral speed V2 of the roller 532 and the photosensitive drum 4
2 is set to 1.2V1 ≦ V2 ≦ 2.5V1, so that a sufficient amount of developer is conveyed to the developing area 535 by the rollers 532 of the developing roller 53, and the peripheral speed of the photosensitive drum 42 is changed. The developer that once adhered to the non-image portion of the electrostatic latent image is appropriately peeled off by the rubbing action of the peripheral surface of the roller 532 against the surface, so that a good toner image having an appropriate development density and no fogging can be obtained. Obtainable. On the other hand, a roller 532 constituting the developing roller 53
The developer used after passing through the developing area 424 is transferred to the surface of the supply roller 54 at the nip portion between the development roller 53 and the supply roller 54. Since the peripheral speed of the supply roller 54 is set to be higher than the peripheral speed of the developing roller 53, the developer is moved in the nip portion. The adhesive force of the transfer developer can be weakened and collected, so that a so-called ghost caused by the non-transfer developer adhered to the developing roller 53 can be prevented. When the photosensitive drum 42 and the developing roller 53 are operated in pressure contact with each other and the peripheral speed V1 of the photosensitive drum 42 is lower than the peripheral speed V2 of the developing roller 53 as in the illustrated embodiment, When the photosensitive drum 42 and the developing roller 53 are driven, the photosensitive drum 42 performs a braking action. Accordingly, in the direction of the helical teeth of the driven gear 70 mounted on the photosensitive drum 42 and the driven gear 501 mounted on the rotating shaft 531 of the developing roller 53, the thrust generated during driving acts toward the back side. They are formed in directions opposite to each other in such an inclined direction.

Although the present invention has been described based on the embodiment in which the present invention is applied to a printer, the present invention is not limited to the illustrated embodiment. For example, the present invention can be applied to an electrostatic copying machine. Various changes or modifications can be made without departing from the scope of the technical idea of the present invention.

[0035]

The image forming apparatus and the photoreceptor unit of the image forming apparatus according to the present invention have the following functions and effects because they are constructed as described above.

That is, according to the present invention, when the guided portion provided on the photoconductor unit comes into contact with the guide portion provided on the fixing unit, both ends of the support shaft of the photoconductor drum are provided on the machine frame. When the photoreceptor unit is mounted on the body frame from above, the guided portion provided on the photoreceptor unit must first be guided by the guide provided on the fixing unit. The two ends of the support shaft of the photosensitive drum are positioned above the shaft support portion provided on the body frame by contacting the photosensitive drum. It can be securely attached to the support portion. Therefore, even when the photoconductor unit and the fixing unit are laid out at a position close to each other, the photoconductor unit can be easily mounted without interfering with the fixing unit when the photoconductor unit is lowered onto the machine frame from above. be able to.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing an embodiment of an image forming apparatus configured according to the present invention.

FIG. 2 is a sectional view of a process unit provided in the image forming apparatus shown in FIG.

FIG. 3 is a perspective view of a main part of a photoconductor unit constituting the process unit shown in FIG. 2;

4 is a perspective view of a main part of a process unit provided in the image forming apparatus shown in FIG.

FIG. 5 is a perspective view of a fixing unit provided in the image forming machine shown in FIG.

6 is a perspective view of a main part of a body frame of the image forming machine shown in FIG.

FIG. 7 is a sectional view taken along line AA in FIG. 1;

FIG. 8 is an explanatory diagram showing a state in which the process unit shown in FIG. 2 is mounted on a machine body frame.

FIG. 9 is an explanatory diagram showing a state in which the process unit shown in FIG. 2 is mounted on a body frame.

[Explanation of symbols]

 2: Printer 3: Body frame 4: Process unit 5: Support shaft 20: Body housing 21: Housing body 23: Cover 31: Bottom wall of body frame 32: Front side wall of body frame 31: Back side wall of body frame 34 : Shaft support 35: shaft support 36: drive gear for photosensitive drum 37: drive gear for developing roller 40: photosensitive unit 41: photosensitive support 42: photosensitive drum 43: charging means 44: foreign matter collection brush 45 : Guide plate pair before transfer 46: guide plate after transfer 47: toner intrusion prevention wall 50: developing unit 51: developing housing 52: coil spring 53: developing roller 54: supply roller 55: stirring means 56: developer regulating means 57: Lid 58: Sheet-shaped sealing member 60: Fixing unit 61: Discharge tray 63: Laser unit 64: Paper feed Ray 65: Paper feed roller 66: Friction pad 67: Transfer roller 70: Driven gear of photosensitive drum 72: Packing 71: Flange 341: Guide groove 342: Fitting groove 343: Pressing member 344: Metal plate 345: Frame base 351: Guide groove portion 352: Fitting groove portion 352a: Shaft contact portion 411: Side wall member of photoconductor support means 411a: Guided portion 412a: Connection member of photoconductor support means 412b: Connection member of photoconductor support means 431: Charging Corona discharger 420: photosensitive drum support shaft 422: charging area 423: electrostatic latent image forming area 424: developing area 425: transfer area 470: toner intrusion prevention wall 501: driven gear of developing roller 503: supply roller Driven gear 504: Driven gear of each group means 514: Stirring chamber 515: Development chamber 517: Development housing Connecting member 533: developer holding area 534: developer regulating area 561: blade 601: fixing housing 601a: transfer paper introduction opening 601b: transfer paper discharge opening 601c: guide section 602: fixing roller pair 603: discharge roller pair

Claims (4)

[Claims] 1. A photoconductor unit comprising a photoconductor drum and photoconductor support means for supporting a support shaft of the photoconductor drum is configured to be detachably mounted on a machine frame from above, and a transfer paper of the photoconductor unit is transported. An image forming machine provided with a fixing unit having a fixing roller pair and a fixing housing accommodating the fixing roller pair on the downstream side in the direction, wherein both ends of the support shaft of the photosensitive drum are provided on the machine frame. A shaft support portion for supporting each is provided, and the photoconductor support means is provided with a guided portion at a lower portion facing the fixing unit, and the fixing unit is opposed to the photoconductor unit. A guide portion for guiding the guided portion is provided on a side surface, and when a guided portion provided on the photoconductor supporting means of the photoconductor unit comes into contact with a guide portion provided on the fixing unit, Photoconductor Dora Both ends of the support shaft are configured to be positioned on top of the shaft support portion provided in 該機 body frame, an image forming machine, characterized in that. 2. The shaft support portion provided on the body frame is formed so as to extend upward and open upward or open, and is formed to be connected to a lower end of the guide groove portion to form a support shaft. The image forming apparatus according to claim 1, wherein the image forming apparatus includes a fitting groove having a width corresponding to a diameter. 3. The photosensitive member supporting means includes a pair of side wall members respectively supporting both ends of a support shaft of the photosensitive drum.
The image forming apparatus according to claim 1, wherein a guided portion is provided at a lower portion of an end surface of the pair of side wall members facing the fixing unit. 4. An image comprising a photoconductor drum and photoconductor support means for supporting a support shaft of the photoconductor drum, the image being configured to be detachable from above on a machine frame mounted on a machine housing provided with a fixing unit. A photoconductor unit of the forming machine, wherein the photoconductor support means is provided with a guided portion at a lower portion facing the fixing unit, and a photoconductor unit provided on the photoconductor support means of the photoconductor unit is provided. When the guide portion is brought into contact with the guide portion provided on the fixing unit, both ends of the support shaft of the photosensitive drum are positioned above the shaft support portion provided on the body frame. A photosensitive unit for an image forming machine.