JP3355472B2 - Image forming machine process unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process unit of an image forming machine which is detachably mounted on a body housing of an image forming machine such as an electrostatic copying machine or a laser printer.

[0002]

2. Description of the Related Art A typical example of the above process unit is a photosensitive unit having a photosensitive drum on the surface of which an electrostatic latent image is formed by exposure means, a developing housing containing a developer, and a developing unit. A developing unit provided in the housing and having a developing roller for applying a developer to the photosensitive drum on which the electrostatic latent image is formed, and swingably supporting the developing unit with respect to the photosensitive unit; A support shaft, and spring means interposed between the photoreceptor unit and the developing unit for biasing the developing unit toward the photoreceptor unit about the support shaft, and is detachable from the machine housing. It is configured to be attached to. An input gear for transmitting a driving force to the developing roller is provided in the developing unit of the process unit having the above-described configuration, and the input gear is configured to mesh with a driving gear provided on the machine housing. Have been.

[0003]

In the above-described process unit, when a drive force acts on the input gear from the drive gear, a reaction force acts on the support shaft, and the support shaft is bent. Occurs. When the support shaft is bent in this way, the side of the developing unit supported by the support shaft on which the input gear is disposed is displaced, so that the developing roller disposed in the developing unit and the photosensitive drum are parallel. The degree changes. For this reason, the pressing force of the developing roller against the photosensitive drum becomes non-uniform, and a phenomenon occurs in which a gray image is whitened out at an end. In order to solve such a problem, the rigidity of the support shaft that swingably supports the photoreceptor unit and the developing unit may be increased to prevent the support shaft from bending. In order to provide a support shaft having the above, the diameter must be increased, and there is a problem that the entire process unit becomes large and the weight increases.

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 is formed without increasing the diameter of a support shaft for swingably supporting a photosensitive unit and a developing unit. An object of the present invention is to provide a process unit of an image forming apparatus capable of securing a parallelism between a photosensitive drum and a developing roller during formation.

[0005]

According to the present invention, there is provided a photoreceptor unit having a photoreceptor drum on which an electrostatic latent image is formed, and a developing device containing a developer. A developing unit including a housing, a developing roller disposed in the developing housing, the developing roller for applying a developer to the photosensitive drum on which the electrostatic latent image is formed, and an input gear for transmitting a driving force to the developing roller; A support shaft for swingably supporting the developing unit with respect to the photoconductor unit; and a developing shaft interposed between the photoconductor unit and the developing unit, the developing unit being attached to the photoconductor unit around the support shaft. A spring means for biasing the image forming apparatus, wherein the input gear is detachably mounted on the body housing, and the input gear is configured to mesh with a drive gear provided on the body housing. A direction in which the axis of the developing roller is bent with respect to the axis of the photosensitive drum in accordance with the amount of deflection of the support shaft due to a drive torque acting on the input gear from the drive gear. A process unit of the image forming machine, wherein the process unit is inclined in a direction opposite to the above.

Further, according to the present invention, an image forming machine is configured such that a direction of a drive pressure angle of the drive gear with respect to an input gear or a direction directly opposite to the direction is directed to the support shaft in a driving state. Are provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a process unit of an image forming machine constituted 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 equipped with a process unit configured according to the present invention.

FIG. 1 schematically shows a printer 2 equipped with an embodiment of a process unit constructed according to the present invention. In this embodiment, the printer 2 is a small and low-speed laser printer used as a printing device such as a word processor, and has a body housing 20 formed of a synthetic resin. 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 process unit 4 is detachably mounted at a substantially central portion of the body housing 20 configured as described above.

As shown in FIG. 2, the process unit 4 includes a photosensitive unit 40 and an electrostatic latent image developing device supported by the photosensitive unit 40 via a support shaft 5 so as to be swingable. Developing unit 50. The photoreceptor unit 40 includes a photoreceptor support means 41, and the photoreceptor support means 41 is provided with a pair of side wall members 411 spaced apart in the front-rear direction (only the rear side wall member is shown in FIG. 2). Shown) and the pair of side wall members 4
11 connecting members 412a, 412b connecting the lower portions
It has. The connecting members 412a and 412b are
The inner surfaces facing each other are arranged in parallel to form a charging means mounting space 412c in which a charging means described later is arranged between the two. 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. A pair of side wall members 411 and 411 constituting the photoconductor supporting means 41 are provided at upper ends on the developing unit 50 side with support side walls 4 having support holes 414a and 414b.
13a and 413b are provided integrally with each other.
(See FIG. 4) By inserting a support shaft 5 made of a metal bar disposed in a later-described developing housing of the developing unit 50 into the supporting holes 414a and 414b provided in the supporting side walls 413a and 413b, the photosensitive is formed. The body unit 40 and the developing unit 50 are supported so as to be swingable with each other. This support structure will be described later in detail.

The photoreceptor unit 40 includes a photoreceptor drum 42 having a photosensitive layer formed on a peripheral surface. The photoconductor drum 42 is rotatably supported by a support shaft 421, and the support shaft 421 is supported by a pair of side wall members 411 constituting the photoconductor support unit 41. A driven gear 420 is mounted on the front end of the photosensitive drum 42 (see FIG. 3). The driven gear 420 meshes with a driving gear to be described later, and a direction indicated by an arrow, that is, a charging area 4 is provided.
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 412 c 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. Charging means 43
A charging corona discharger 431 as a charger disposed in parallel with the photosensitive drum 42 along the axial direction; and a charger holding member 432 made of 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 is positioned at a predetermined position. Charging means 43 thus configured
Charges the peripheral surface of the photosensitive drum 42 to 800 to 850V. Further, between the transfer area 425 and the charging area 422, a foreign matter collecting means 44 for removing foreign matter such as paper dust adhering to the peripheral surface of the photosensitive drum 42 is provided.

The foreign matter collecting means 44 includes a photosensitive drum 4
A foreign matter collecting brush 441 having substantially the same length as the second axial length and being brought into contact with the peripheral surface of the photosensitive drum 42 is provided. In the illustrated embodiment, the foreign matter collecting brush 441 is made of a conductive material such as rayon resin containing carbon particles to have a length of about 2 mm.
It is attached to a conductive sheet member 442 having flexibility. The conductive sheet member 442 is made of, for example, a woven fabric in which metal fibers are blended, and the above-described foreign matter collecting brush 441 is implanted in the conductive sheet member 442 made of the woven fabric. This conductive sheet member 442
Is mounted on the ground member 444 via the elastic holding member 443. In the illustrated embodiment, the elastic holding member 443 is made of an elastic material such as a sponge material and has a thickness of about 3 mm, and the front and back surfaces thereof are bonded to the conductive sheet member 442 and the ground member 444 with an appropriate adhesive. Have been. The conductive sheet member 4
The tongue 42 is provided with a tongue at the front end thereof. The tongue is sandwiched between the grounding member 444 and the elastic holding member 443, and is adhered to the grounding member 444 by a conductive adhesive. The grounding member 444 is made of, for example, a metal plate such as a stainless steel plate, and a part thereof is provided with a connecting portion 444a formed to protrude downward. The ground member 444 thus configured is attached to a brush supporting member 445 integrally formed with the charger holding member 432 and disposed along the axial direction of the photosensitive drum 42 by, for example, a double-sided adhesive tape. The connecting portion 444a of the ground member 444 is
5, is inserted into the charging means mounting space 412c of the photosensitive member support means 41 through the opening 445a, and is brought into contact with the conductive plate 447 provided in the charging means mounting space 412c. Therefore, the peripheral surface of the photosensitive drum 42 has a foreign matter collecting brush 44 made of a conductive material.
1. The body is laid via the conductive sheet member 442, the ground member 444, and the conductive plate 447. The foreign matter means 44 in the illustrated embodiment is configured as described above, and the pressing force of the foreign matter collecting brush 441 against the peripheral surface of the photosensitive drum 42 can be obtained by compressing the elastic holding member 443. There is no need to bend the foreign matter collection brush in order to obtain. Accordingly, the length of the foreign matter collecting brush 441 can be reduced, so that the so-called brush becomes stiff and the performance of removing paper dust and the like is improved. Further, since the foreign matter collecting brush 441 is connected to the ground member 444 by the tongue piece 442a of the conductive sheet member 442, there is no possibility that a member having high hardness contacts the peripheral surface of the photosensitive drum 42. No damage to the surrounding surface.

Returning to FIG. 2, the upper end of the charger holding member 432 is located between the charging corona discharger 431 disposed in the charging area 422 and the foreign matter collecting brush 44. And is formed so as to protrude so as to be close to the peripheral surface of the toner, and forms a toner intrusion prevention wall 47. The toner intrusion prevention wall 47 is attached to the peripheral surface of the photosensitive drum 42 and the residual toner removed by the foreign matter collecting brush 441 together with foreign matter such as paper dust falls without being reliably captured by the foreign matter collecting brush 441. To
It has a function of preventing intrusion on the charging corona discharger 431. As a result, the toner intrusion prevention wall 47
The toner whose movement has been blocked by this is accumulated on the horizontal piece near the toner intrusion prevention wall 47 of the brush support member 440.

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 mainly with reference to FIGS. 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 and a front wall and a rear wall 512 (FIG. 2) formed to stand upright from front and rear ends (ends in a direction perpendicular to the paper surface in FIG. 2) of the bottom wall 511. Only the rear side wall is shown) and a left side wall 513, which are integrally formed of a synthetic resin, and a stirring chamber 514 and a developing chamber 5 are formed.
15 are specified. A partition wall 516 provided in the front-rear direction (the direction perpendicular to the paper surface in FIG. 2) between the stirring chamber 514 and the developing chamber 515 is integrally formed with the bottom wall 511 constituting the developing housing 51. This partition wall 5
The left and right sides of the guide 16 are arc-shaped guide surfaces 516a and 516a.
6b. Between the front and rear side walls 512 constituting the developing housing 51, a connecting member 517 provided at the upper part on the side of the developing chamber 515 is provided, and is formed integrally with the front and rear side walls 512. A toner supply hole 518 is formed in the rear side wall 512 of the developing housing 51, and a cap 519 is fitted in the toner supply hole 518. Support side walls 591a and 591b having support holes 592a and 592b are provided integrally at the upper ends of the front and rear side walls 512 and 512 of the thus configured developing housing 51 on the side of the developing chamber 515, respectively. The support shaft 5 is inserted into the support holes 592a and 592b formed in the support side walls 591a and 591b, and the photosensitive unit 40 and the developing unit 50 are supported so as to be able to oscillate with each other. This will be described in detail. A coil spring 52 as a spring means is interposed between the lower end of the photoconductor support means 41 of the photoconductor unit 40 and the lower end of the developing housing 51 at the front end and the rear end, respectively. The photoreceptor support means 41 and the developing housing 51 are urged by a 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,
In the illustrated embodiment, the driven gear 501 functions as an input gear for inputting a driving force from a driving gear described later to the developing unit 50 side. A transmission gear 502 is integrally formed behind the driven gear 501. By the rotation of the rotation shaft 531, the roller 532 is also driven to rotate in the direction shown by the arrow, and the peripheral surface of the roller 532 is sequentially moved through the developer holding area 533, the developer regulating area 534, and the developing area 424. 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 area 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 gear 502. Therefore, the rotation shaft 5 of the supply roller 54
41 is the direction indicated by the 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. 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 2 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 is a regulating blade 5 made of a flexible and elastic thin steel plate which is pressed against the peripheral surface of the roller 532 constituting the developing roller 32.
61 are provided. The regulating blade 561 is, for example,
It is made of a stainless steel plate or a spring steel plate having a thickness of about 0.1 to 0.2 mm, and has a longitudinal dimension substantially the same as the length of the roller 532 constituting the developing roller 53. The regulating blade 561 has a mounting portion 561a and a regulating portion 561b. A regulating member 562 made of urethane rubber is mounted on the surface (on the side facing the developing roller 32) of the regulating portion 561b constituting the regulating blade 561. In the illustrated embodiment, the restricting member 562 has a semicircular cross section with a radius of about 1 mm, has substantially the same length as the longitudinal dimension of the restricting blade 561, and has a flat surface on the surface of the restricting portion 561b. Mounted with adhesive. Mounting part 561 of regulating blade 561
a is a blade mounting portion 5 provided at an open end of the bottom wall 511 of the developing housing 51 on the photoconductor unit 40 side.
11a, it is clamped and attached by the holding plate 563. Mounting part 561a of regulating blade 561 and holding plate 5
63 and between the mounting portion 561a and the developing housing 51.
In the illustrated embodiment, elastic members 564 and 564 made of a sheet material of urethane rubber having a thickness of about 0.2 to 0.3 mm are arranged between the blade mounting portions 511a. The blade mounting portion 511a of the developing housing 51, the mounting portion 561a of the regulating blade 561, and the elastic member 56
4, 564 and the holding plate 563 are provided with a plurality of screw insertion holes at predetermined positions at positions corresponding to each other in the longitudinal direction. A plurality of screws 565 are inserted into the plurality of screw insertion holes provided in each of the above members from the blade mounting portion 511a side of the developing housing 51, and a screw portion 565a formed at the tip of the screw 565 is pressed. By screwing into a female screw 563a formed in a screw insertion hole provided in the plate 563, the mounting portion 561a of the regulating blade 561 is pressed onto the blade mounting portion 511a of the developing housing 51 via the elastic members 564 and 564. 563 and clamped and fixed. As described above, the mounting portion 561a of the regulating blade 561 is
Since the screw 565 is attached to the blade attachment portion 511a of the developing housing 51 via the intermediate members 64, 564, the tightening force of the screw 565 is dispersed by the elastic members 564, 564. Accordingly, deformation of the holding plate 563 can be suppressed even if its rigidity is not very high, and deformation of the regulating blade 561 due to deformation of the holding plate 563 by the tightening force of the screw 565 can be reduced. In the illustrated embodiment, an example is shown in which the elastic members 564 and 564 are provided on both sides of the mounting portion 561a of the regulating blade 561, but only between the mounting portion 561a of the regulating blade 561 and the pressing plate 563. Even when the elastic member 564 is provided, the dispersion of the tightening force is slightly reduced as compared with the case where the elastic members are provided on both sides, but a sufficient effect of reducing the deformation of the regulating blade 561 can be obtained.

A fulcrum member mounting portion 511b is provided above the blade mounting portion 511a in the developing housing 51.
Are formed in the front-rear direction (the direction perpendicular to the plane of FIG. 2). The fulcrum member mounting portion 511b is formed by an arc-shaped groove in the illustrated embodiment. A fulcrum member 566 is provided at the fulcrum member attachment portion 511b. The fulcrum member mounting portion 511b is made of, for example, a 2 mm metal round bar in the illustrated embodiment, and has substantially the same length as the longitudinal dimension of the regulating blade 561. The fulcrum member 566 is placed on the fulcrum member attachment portion 511b, and the back surface between the mounting portion 561a and the restriction portion 561b of the restriction blade 561 (the surface opposite to the surface on which the restriction member 562 is mounted).
It is configured to abut against. The fulcrum member 56
6 is desirably disposed at such a position that the contact position of the regulating blade 561 is as far as possible from the regulating member 562 in order to achieve downsizing of the regulating blade 561. The developer regulating means 56 thus configured is such that the regulating blade 561 is flexed with the fulcrum member 566 as a fulcrum, and the regulating member 562 mounted on the surface of the regulating portion 561b moves the developing roller 53 in the developer regulating area 534. Constituting roller 5
32 is pressed against the peripheral surface. Developer regulating means 56
Is configured as described above, and since the fulcrum member 566 serving as the fulcrum of the deflection of the regulating blade 561 is made of a round bar, a relatively accurate fulcrum can be obtained at low cost. In the illustrated embodiment, the fulcrum member 5
Although an example in which a round bar is used as 66 is shown, a square bar may be used.

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.

Next, a support (connection) structure between the photosensitive unit 40 and the developing unit 50 constructed according to the present invention will be described with reference to FIGS. Support holes 414a and 414b having a common axis are formed in a pair of support side walls 413a and 413b provided on a pair of side wall members 411 and 411 constituting the photoreceptor support means 41 of the photoreceptor unit 40, respectively. . The portion of the support side wall 413a on the near side (the right side in FIG. 4) where the support hole 414a is formed protrudes toward the near side (the right side in FIG. 4) to form a support boss portion 415. On the other hand, support holes 592a and 592b having a common axis are formed in a pair of support side walls 591a and 591b provided at upper ends of the front and rear side walls 512 and 512 of the development housing 51 on the side of the development chamber 515, respectively. . The pair of support side walls 591a and 591b has an outer width (the maximum width in the left-right direction in FIG. 4) of the pair of support side walls 41.
A pair of inner support side walls smaller than the inner width of 3a and 413b (the minimum width in the left-right direction in FIG. 4) is defined. Accordingly, the pair of supporting side walls 413a and 413b define a pair of outer supporting side walls.

The support shaft 5 is made of a metal rod member having a circular cross section, and has a large diameter portion 5a and a step 5c formed on the large diameter portion 5a.
At the one end (right end). A bearing member 593 is detachably mounted on the support side wall 413b. The bearing member 593 is a cylindrical portion 593
a, and a support hole 593b is formed in the cylindrical portion 593a. The support hole 593b has an open end 593c and a closed end 5
93d. The open end 593c is a cylindrical portion 593a.
Defines the inside edge of A mounting flange 593e extending radially outward is formed substantially at the center of the cylindrical portion 593a in the axial direction, and the mounting flange 593e is formed on the outer support side wall 413b.
The receiving concave portion 413c in which is received is formed.
The bearing member 593 has its cylindrical portion 593a fitted into the support hole 414b of the outer support side wall 413b, and the mounting flange 5
93e is fitted into the receiving recess 413c, and the mounting flange 5
93e is fixed to the outer support side wall 413b with the bolt B so as to be detachably attached to the outer support side wall 413b (the state of FIG. 4).

As described above, with the bearing member 593 mounted on the outer supporting side wall 413b, the inner supporting side wall 5
Support holes 592a and 5a of respective 91a and 591b
92b is rotatably fitted to the large diameter portion 5a of the support shaft 5. The support hole 414a of the outer support side wall 413a is
Is rotatably fitted to the small diameter portion 5b. Bearing member 593
Is rotatably fitted to the other end (left end) of the support shaft 5. The outer side surface (right side surface) of the inner support side wall 591a is in contact with the inner side surface (left side surface) of the outer support side wall 413a. Outer side surface (left side surface) of inner support side wall 591b
Is in contact with the open end 593c of the bearing member 593. The step 5c of the support shaft 5 is in contact with the inner side surface (left side surface) of the outer side wall 413a. The end surface of the other end (left end) of the support shaft 5 is positioned at a distance from the closed end 593d of the bearing member 593. The outer side surface (left side surface) of the inner support side wall 591b is configured to directly contact the inner side surface (right side surface) of the outer support side wall 413b instead of abutting on the open end 593c of the bearing member 593. Good. The other end of the support shaft 5 is positioned in the support hole 414b of the outer support side wall 413b via the cylindrical portion 593a of the bearing member 593.

The support shaft 5 is moved from the small diameter portion 5b side to the support hole 414b of the outer support side wall 413b, the inner support side wall 591b.
Support hole 592b, support hole hole 9 in the inner support side wall 591a.
After inserting from the left to the right in FIG. 4 in the order of 2a and the support hole 414a of the outer support side wall 413a, while inserting the cylindrical portion 593a of the bearing member 593 into the support hole 414b of the outer support side wall 413b, The photosensitive member unit 40 and the developing unit 50 are connected to the support shaft 5 by a simple assembling operation in which the other end of the support shaft 5 is fitted into the support hole 593b and the bearing member 593 is mounted on the outer support side wall 413b. Can be swingably supported via each other.

Further, the bearing member 593 is connected to the outer support side wall 41.
3b, the support holes 592a and 592b of the inner support side walls 591a and 591b are fitted into the large-diameter portion 5a of the support shaft 5, and the outer support side wall 413 is mounted.
The support hole 414a of the support shaft 5a is fitted into the small-diameter portion 5b of the support shaft 5, the support hole 593b of the bearing member 593 is fitted into the other end of the support shaft 5, and the outer side surface of the inner support side wall 591a is 413a, the inner supporting side wall 5
Since the outer surface of 91b is in contact with the open end 593c of the bearing member 593 or the inner surface of the outer support side wall 413b,
The axial movement of the support shaft 5 in the inner support side walls 591a and 591b with respect to each of the outer support side walls 413a and 413b is reliably restricted. Also, in the assembled state in which the bearing member 593 is mounted on the outer support side wall 413b, the step portion 5c of the support shaft 5 abuts on the inner side surface of the outer support side wall 413a, and the end surface at the other end of the support shaft 5 is a bearing. Since the support shaft 5 is positioned at an interval at the closed end 593d of the member 593, the support shaft 5 is reliably prevented from coming off in the axial direction.

Further, the bearing member 593 is connected to the outer support side wall 41.
3b, the other end of the support shaft 5 is connected to the outer support side wall 4 via the cylindrical portion 593a of the bearing member 593.
By being positioned in the support hole 414b of the support shaft 13b, the outer support side wall 413b is supported by the other end of the support shaft 5 via the support hole 414b and the cylindrical portion 593a of the bearing member 593. The applied load is firmly and securely supported by the other end of the support shaft 5. Also, an excessive load on the cylindrical portion 593a of the bearing member 593 is prevented, and the deformation is prevented.

The process unit 4 configured as described above is removably mounted on the body frame 3 provided on the housing body 21 of the body housing 20. Next, the body frame 3 will be described with reference to FIGS. 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 as shown in FIG.
1 and a front side wall 32 and a rear side wall 33. One shaft support portion 34 for supporting one end of the support shaft 421 of the photosensitive drum 42 is provided on the front side wall 32 of the body frame 3, and the support shaft 4 is provided on the back side wall 33.
The other shaft support 35 that supports the other end of the shaft 21 is provided. One of the shaft support portions 34 provided on the front side wall 32 of the body frame 3 is formed with a guide groove 341 that is formed so as to expand upward and is open at the top, and the guide groove 341.
And a fitting groove 342 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 341a that slopes inward from the upper end is formed on the outer wall that forms the guide groove 341. A support recess 344 is formed at the upper end of the front side wall 32, and a support side wall provided on the front side wall member 411 that constitutes the photoconductor support unit 41 of the photoconductor unit 40 in the support recess 344. Support boss 4 formed at 413a
15 are placed. The other shaft support 35 provided on the rear side wall 33 of the body frame 3 is
A guide groove 351 that is provided to face the one shaft support portion 34 provided on the front side wall 32 and that is formed so as to extend upward and is open at the top similarly to the shaft support portion 34; The fitting groove 35 formed to be connected to the lower end of the guide groove 351 and having a width corresponding to the diameter of the support shaft 420.
2 is provided. 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. And functions as the shaft contact portion 352a. Also, the rear side wall 32
A support concave portion 354 is formed at the upper end of the photoconductor unit 40. A bearing mounted on a support side wall 413a provided on a rear side wall member 411 constituting the photoconductor support means 41 of the photoconductor unit 40 in the support concave portion 354. The member 593 is mounted.

A driven gear 420 mounted on one end of the photosensitive drum 42 when the support shaft 420 of the photosensitive drum 42 is mounted on the shaft supports 34 and 35 on the front side wall 32 of the body frame 3. A drive gear 36 is provided which meshes with the drive gear 36. A drive gear 37 meshingly engaged with a driven gear 501 mounted on a rotation shaft 531 of the developing roller 53 is provided on the front side wall 32 of the body frame 3.
Are arranged. 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 body 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, the support shaft 4 of the photosensitive drum 42
3 are guide groove portions 341 of shaft support portions 34 and 35
And 351 guided by the fitting grooves 342 and 352
, The driven gear 420 mounted on one end of the photosensitive drum 42 meshes with the driving gear 36, and the driven gear 501 mounted on the rotating shaft 531 of the developing roller 53 connects with the driving gear 37. Engage with each other. A support side wall 413a provided on the front side wall member 411 constituting the photoreceptor support means 41 of the photoreceptor unit 40
Support boss 415 formed at the upper end of the front side wall 32 constituting the body frame 3
And a bearing member 593 mounted on a support side wall 413a provided on a back side wall member 411 constituting the photoreceptor support means 41 of the photoreceptor unit 40, the back side wall 32 constituting the body frame 3 Is placed on a support recess 354 formed at the upper end of the. The body 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. When the process unit 4 is mounted on the body frame 3 as described above, the cover 23 is rotated around the shaft 22 in FIG.
By turning clockwise in, the upper part is closed.

Next, the drive gear 37 and the developing roller 53
The relationship between the driven gear 501 mounted on the rotary shaft 531 and the support shaft 5 will be described with reference to FIG. As described above, in a state where the process unit 4 is mounted on the body frame 3, the driven gear 501 mounted on the rotating shaft 531 of the developing roller 53 is engaged with the driving gear 37 and rotates in the direction indicated by the arrow. The driven gear 501 is driven to rotate in the direction indicated by the arrow by the driving gear 37. In the illustrated embodiment, the driven gear 501 is the driving gear 3
7, the direction F of the drive pressure angle of the drive gear 37 with respect to the driven gear 501 in the state of meshing engagement with the support shaft 5 is configured to be directed in the opposite direction to the support shaft 5. When the support shaft 5 is disposed below the meshing position between the drive gear 37 and the driven gear 501, the direction F of the drive pressure angle of the drive gear 37 with respect to the driven gear 501 is It is configured to be directed to In the state shown in the figure, when the driven gear 501 is driven to rotate in the direction indicated by the arrow by the driving gear 37, the driving pressure angle direction F
Is applied to the support shaft 5 via a pair of support side walls 591a and 591b provided on the front and rear side walls 512 and 512 constituting the developing housing 51, respectively. The force acting on the support shaft 5 based on the drive torque is mainly applied downward (in the direction F of the drive pressure angle) from the support side wall 591a on the near side where the driven gear 501 is provided. For this reason, the support shaft 5 is
Support side wall 591a closer to the front than the portion supporting 91b
Because the portion supporting the developing housing 51 is largely bent, the front side of the developing housing 51 supported by the support shaft 5 is displaced downward. Accordingly, the developing roller 53 provided in the developing housing 51 has a front side where the driven gear 501 is provided.
Since it is displaced downward as indicated by the dotted line, the parallelism with the photosensitive drum 42 changes. According to experiments by the present inventors, when the support shaft 5 having a diameter of 5 mm and a length of 276.5 mm is used (the interval between the pair of support side walls 413a and 413b is 259.5 mm), the lower side of the front side of the developing roller 53 is used. Was about 0.3 mm.

According to the present invention, the driving gear 37 to the driven gear 5
01 caused by transmission of the driving torque to the developing roller 5
7, the axis 53a of the developing roller 53 is inclined upward on the driven gear 501 side (the right side in FIG. 7) with respect to the axis 42a of the photosensitive drum 42 as shown in the actual battle in FIG. It is arranged. That is, the axis 53a of the developing roller 53 is inclined with respect to the axis 42a of the photosensitive drum 42 in a direction opposite to the direction in which the support shaft 5 bends. With this configuration, the driving force is transmitted from the driving gear 37 to the driven gear 501, and the support shaft 5 is bent, and as shown by a two-dot chain line in FIG. In the state of being displaced downward, the axis 53a of the developing roller 53 is
Is parallel to the axis 42a. Therefore, during image formation in which the driving torque is transmitted from the driving gear 37 to the driven gear 501, the parallelism between the developing roller 53 and the photosensitive drum 42 is ensured.

When the driven gear 501 is driven from the driving gear 37 to the driven gear 501 as described above, the front side of the developing roller 53 where the driven gear 501 is disposed is displaced downward. Are slightly displaced as shown by the two-dot line in FIG. Therefore, the axis 5 of the support shaft 5
00 so that the driving gear 37 and the driven gear 5 are positioned on a line exactly opposite to the driving pressure angle direction F indicated by a two-dot line in advance.
By setting the positional relationship between 01 and the support shaft 5,
No driving torque is generated around the support shaft 5 with respect to the developing housing 51. Therefore, the pressure contact force between the developing roller 53 and the photosensitive drum 42 can be stably maintained.

Returning to FIG. 1, a description will be given of the housing body 21 of the body housing 20 of the printer 2.
The laser unit 24 is provided below the. The laser unit 24 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 addition, the post-transfer guide plate 46 is provided on the housing main body 21 constituting the body housing 20 of the printer 2.
A fixing roller pair 25 is disposed downstream of the fixing roller pair 25, and a discharge roller pair 26 is disposed downstream of the fixing roller pair 25. Further, the discharge tray 2 is located downstream of the discharge roller pair 26.
7 are provided.

In a cover 23 constituting the body housing 20 of the printer 2, a paper feed tray 28 on which transfer paper is placed is disposed at an upper left side in FIG. A paper feed roller 29 is provided downstream of the paper feed tray 28,
The paper feed roller 29 is driven to rotate in a direction indicated by an arrow in FIG. A friction pad 30 for separating sheets is provided opposite to the sheet feeding roller 29. Further, a non-contact type transfer roller 31 is provided in the transfer area 422 so as to face the photosensitive drum 42. The transfer roller 31 is formed of conductive urethane foam, and is rotatably supported by the cover 23. The transfer roller 31 is provided with collars (not shown) made of an insulating material such as a synthetic resin having an outer diameter larger than that of the transfer roller 31 at both ends thereof, and the collars are arranged in contact with the peripheral surface of the photosensitive drum 42. Has been
Accordingly, the transfer roller 31 is driven to slide while the photosensitive drum 42 rotates. The gap between the peripheral surface of the transfer roller 31 and the peripheral surface of the photosensitive drum 42 is 0.5 m.
m. A constant current of, for example, 10 μA is applied to the transfer roller 31 configured as described above.
An upper guide plate 452 constituting the other of the pre-transfer guide plate pair 45 is disposed on the cover 23.

The printer 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 on which the toner image has been transferred is guided by the guide plate 46 after the transfer, and is conveyed to the fixing roller pair 25. The transfer paper on which the toner image has been heated and fixed by the fixing roller pair 25 is discharged onto a discharge tray 27 by the discharge roller pair 26. On the other hand, when the peripheral surface of the photosensitive drum 42 that has passed through the transfer area 425 passes through the foreign matter collecting brush 441 of the foreign matter collecting means 44, foreign matter such as paper dust adhered to the peripheral surface is removed by the foreign matter collecting brush 441.
Removed by At this time, residual toner adhering to the peripheral surface of the photosensitive drum 42 is removed together with foreign matter such as paper dust. 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, the toner intrusion prevention wall 47 causes the dropped toner to move toward the charging corona discharger 431. Intrusion is prevented.

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 conveyed to the developer holding area 533, which is a nip portion between the supply roller 54 and the developing roller 53, is supplied 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, a regulating member 562 mounted on the surface of the blade 561 constituting the developer regulating means 56 acts on the developer held on the peripheral surface of the roller 532 of the developing roller 53. And the roller 532
The developer held on the peripheral surface is regulated to a required amount to form a thin layer. In the developer regulation area 534, the bottom wall 51 of the development housing 51 is regulated by the regulation member 562 attached to the blade 561 of the developer regulation means 56.
The developer scraped off onto 1 is conveyed along the guide surface 516b of the partition wall 516 without stopping because the supply roller 54 is rotated in the direction shown by the arrow.

As described above, the regulating member held on the peripheral surface of the roller 532 constituting the developing roller 53 in the developer retaining area 533 and the regulating member mounted on the regulating blade 561 of the developer regulating means 56 in the developer regulating area 534. 562
The developer formed in a thin layer by the action of is transported to the developing area 424 with rotation in the direction of the arrow. In the developing area 424, a developer is applied to the electrostatic latent image on the electrostatic photosensitive member disposed on the peripheral surface of the photosensitive drum 42,
The electrostatic latent image is developed into a toner image. For example, the electrostatic latent image has a non-image area charged to about +600 V and + 12V.
It has an image area charged to about 0 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 a direction indicated by an arrow in FIG.
In the developing area 535, the peripheral surface of the photosensitive drum 42 and the peripheral surface of the roller 532 constituting the developing roller 53 are both moved upward from below in the same direction. Roller 532
And the peripheral speed V1 of the photosensitive drum 42 are as follows.
Since 2V1 ≦ V2 ≦ 2.5V1, a sufficient amount of developer is conveyed to the developing area 535 by the roller 532 of the developing roller 53, and the peripheral surface of the roller 532 slides on the peripheral surface of the photosensitive drum 42. The developer that has once adhered to the non-image portion of the electrostatic latent image is appropriately peeled off by the rubbing action, so that a good toner image having an appropriate development density and no fog can be obtained. On the other hand, the used developer held on the peripheral surface of the roller 532 constituting the developing roller 53 and passing through the developing area 424 is transferred to the surface of the replenishing roller 54 at the nip portion between the developing roller 53 and the replenishing roller 54. It is. 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.

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, and can be applied to, for example, an electrostatic copying machine. Various changes or modifications can be made without departing from the scope of the technical idea of the present invention.

[0043]

The process unit of the image forming apparatus according to the present invention is configured as described above, and has the following effects.

That is, the present invention relates to a process unit of an image forming machine which supports a photoreceptor unit and a developing unit so as to be swingable by a support shaft and is detachably mounted on the machine housing. The axis of the developing roller provided in the developing unit is arranged in the photosensitive unit in accordance with the amount of deflection of the support shaft due to the driving torque acting on the input gear provided in the developing unit from the provided driving gear. The support roller is inclined in the direction opposite to the direction of deflection of the support shaft with respect to the axis of the photosensitive drum, so that when the drive torque is transmitted from the drive gear to the input gear, the parallelism between the developing roller and the photosensitive drum is secured. Is done. As described above, the parallelism between the developing roller and the photosensitive drum can be ensured without increasing the rigidity of the support shaft. Therefore, it is not necessary to use a large-diameter support shaft to secure the rigidity. The size and weight of the entire unit can be reduced.

Further, according to the present invention, since the direction of the drive pressure angle of the drive gear with respect to the input gear or the direction opposite to the direction is directed to the support shaft in the driven state, the developing No drive torque is generated around the support shaft for the unit. Therefore, the pressure contact force between the developing roller and the photosensitive drum can be stably maintained.

[Brief description of the drawings]

FIG. 1 is a front view schematically illustrating an image forming apparatus equipped with an embodiment of a process unit configured according to the present invention.

FIG. 2 is a cross-sectional view of the process unit of FIG.

FIG. 3 is a schematic view of a mounting state of a photoconductor unit and a developing unit in the process unit of FIG. 2 as viewed from a side.

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

FIG. 5 is a perspective view of a main part of a body frame of the image forming machine shown in FIG. 1;

FIG. 6 is an explanatory diagram showing a relationship between a driving gear provided on a machine frame, a driven gear (input gear) mounted on a rotating shaft of a developing roller, and a support shaft.

FIG. 7 is an enlarged explanatory diagram illustrating a relationship between a photosensitive drum and an axis of a developing roller.

[Explanation of symbols]

 2: printer 4: process unit 5: support shaft 20: body housing 21: housing body 23: cover 24: laser unit 25: fixing roller pair 26: discharge roller pair 27: discharge tray 28: paper feed tray 29: paper feed tray 29: paper feed Roller 30: Friction pad 31: Transfer roller 40: Photoconductor unit 41: Photoconductor support means 42: Photoconductor drum 43: Charging means 44: Foreign matter recovery means 45: Guide plate 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 seal member 411: side wall of photosensitive member supporting means Member 412: Connecting member of photoconductor supporting means 422: Charging area 423: Electrostatic latent image forming area 424: Current Area 425: Transfer area 431: Corona discharger for charging 441: Foreign matter collecting brush 442: Conductive sheet member 443: Elastic holding member 444: Ground member 445: Brush support member 470: Toner intrusion prevention wall 514: Stirring chamber 515: Development Chamber 517: connecting member of developing housing 533: developer holding area 534: developer regulating area 561: regulating blade 562: regulating member 566: fulcrum member 593: bearing member 413a, 413b: supporting side wall 414a, 414b: supporting hole 591a, 591b: Support side wall 592a, 592b: Support hole 593a: Cylindrical portion 593b: Support hole 593c: Open end 593d: Closed end

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuki Miyaji 1-2-28 Tamazo, Chuo-ku, Osaka-shi Mita Kogyo Co., Ltd. (56) References JP-A-5-66662 (JP, A) JP-A-Hei JP-A-8-286453 (JP, A) JP-A-3-149580 (JP, A) JP-A-5-72826 (JP, A) JP-A-8-30174 (JP, A) A) JP-A-9-160435 (JP, A) JP-A 61-203756 (JP, U) JP-A 60-115271 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) G03G 15/00 550 G03G 21/16-21/18

Claims (2)

(57) [Claims] 1. A photoreceptor unit having a photoreceptor drum on which an electrostatic latent image is formed, a developing housing containing a developer, and a photoreceptor disposed in the developing housing and on which an electrostatic latent image is formed. A developing unit including a developing roller for applying a developer to the body drum and an input gear for transmitting a driving force to the developing roller; and a support shaft for swingably supporting the developing unit with respect to the photosensitive unit. Spring means interposed between the photoreceptor unit and the developing unit for urging the developing unit toward the photoreceptor unit about the support shaft, and is detachably mounted on the body housing. A process unit of an image forming machine, wherein the input gear is configured to mesh with a drive gear provided in the body housing, wherein a drive torque acting on the input gear from the drive gear is provided. Wherein the axis of the developing roller is inclined with respect to the axis of the photosensitive drum in a direction opposite to the direction of bending of the support shaft in accordance with the amount of deflection of the support shaft. unit. 2. A driving pressure angle of the driving gear with respect to the input gear or a direction directly opposite to the driving pressure angle is directed to the support shaft in a driving state.
The process unit of the image forming machine described in the above.