JPH10186983A - Image forming machine and process unit for image forming machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming machine capable of preventing the occurrence of what is called, the toner filming by effectively scraping the toner which is heaped in a foreign matter recovering brush disposed between a transferring area and an electrifying area and restuck to the periphery of a photoreceptor drum. SOLUTION: This image forming machine is provided with the photoreceptor drum 42 which is freely rotatably disposed and passes through the electrifying area 422, an electrostatic latent image area 423, a developing area 424 and the transferring area 425 in order, an electrifier arranged in the electrifying area 422, a developing device arranged in the developing area 424, a transfer means arranged in the transferring area 425 and a foreign matter recovering means 44 which is disposed in contact with the periphery of the drum 42, between the transferring area 425 and the electrifying area 422, so as to remove foreign matter stuck to the periphery of the drum 42. In such a case, the image forming machine is further provided with a melted toner scraping member 47 which is disposed in contact with the outer periphery of the drum 42 between the foreign matter recovering means 44 and the electrifying area 422 and constituted of a foamed body with consecutive air bubbles.

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 and a process unit used in the 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 apparatus includes an apparatus and a transfer 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. Further, between the charging area and the transfer area, there is provided a foreign matter collecting brush which comes into contact with the peripheral surface of the photosensitive drum and removes foreign matter such as paper dust adhered to the peripheral surface of the photosensitive drum.

[0003]

Thus, the foreign matter collecting brush only needs to reliably remove foreign matter such as paper dust adhering to the peripheral surface of the photosensitive drum. Has residual toner adhered thereto after transfer, and a part of the residual toner is removed by a foreign matter collecting brush. The residual toner removed by the foreign matter collecting brush accumulates in the foreign matter collecting brush, and the accumulated toner rubs against the peripheral surface of the photosensitive drum. As a result, the silica component as a surface treatment agent for the toner powder particles is reattached to the peripheral surface of the photosensitive drum. Particularly, in recent years, since the fixing unit for heating and fixing the toner image transferred onto the transfer paper is arranged close to the foreign matter collecting brush due to the miniaturization of the apparatus, the foreign matter collecting brush rubs the peripheral surface of the photosensitive drum. The resulting toner tends to fuse with the heat from the fixing means. The toner fused to the peripheral surface of the photosensitive drum is not removed in the next developing step, and the fused toner becomes a starting point and gradually grows by repeating the image forming operation to form a so-called streak-like toner filter. This results in the occurrence of ming, which adversely affects the subsequent transferred image.

[0004] The present invention has been made in view of the above-mentioned facts, and its main technical problem is to effectively remove toner deposited in the foreign matter collecting brush and re-adhered to the peripheral surface of the photosensitive drum. An object of the present invention is to provide an image forming apparatus and a process unit of the image forming apparatus which can prevent scraping, that is, occurrence of so-called toner filming.

[0005]

According to the present invention, in order to attain the above-mentioned main technical problems, the present invention is arranged rotatably and sequentially passes through a charging area, an electrostatic latent image forming area, a developing area and a transfer area. A photosensitive drum, a charger disposed in the charging area and charging the peripheral surface of the photosensitive drum to a specific polarity, and a peripheral surface of the photosensitive drum disposed in the developing area and in an electrostatic latent image forming area A developing device that develops the electrostatic latent image formed on the photosensitive drum into a toner image, a transfer unit that is provided in the transfer area, and transfers the toner image formed on the peripheral surface of the photosensitive drum to transfer paper; A foreign matter collecting means for removing foreign matter attached to the peripheral surface of the photosensitive drum disposed in contact with the peripheral surface of the photosensitive drum between the charging area and the charging area, A peripheral surface of the photosensitive drum between the foreign matter collecting means and the charged area; Contact is disposed, comprises a fused toner scraping member is constituted by open-cell foam, the image forming apparatus is provided, characterized in that.

Further, according to the present invention, a photosensitive drum rotatably disposed and sequentially passing through a charging area, an electrostatic latent image forming area, a developing area and a transfer area, and the photosensitive drum disposed in the charging area and A charger for charging the peripheral surface of the body drum to a specific polarity; and a developing device provided in the developing area for developing an electrostatic latent image formed on the peripheral surface of the photosensitive drum in a latent image forming area into a toner image A developing device and a foreign matter collecting means disposed between the transfer area and the charged area in contact with the peripheral surface of the photosensitive drum and removing foreign matter attached to the peripheral surface of the photosensitive drum are unitized. And a fusing toner scraping member formed of an open-cell foam and disposed in contact with the peripheral surface of the photosensitive drum between the foreign matter collecting means and the charging area. An image forming machine comprising: Seth unit is provided. Other features of the present invention will become apparent from the following description.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image forming machine constituted according to the present invention and a process unit used in the image forming machine 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 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. At the upper end of the pair of side wall members 411 constituting the photoconductor supporting means 41 on the developing unit 50 side, mounting holes 4 are provided.
14 are provided. 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. The photosensitive drum 42 has a rotating shaft 421. The rotating shaft 421 is rotatably supported by a pair of side wall members 411 constituting the photosensitive member supporting means 41. That is, it is driven to rotate so as to sequentially pass through the charging area 422, the electrostatic latent image forming area 423, the developing area 424, and the transfer area 425. Charge area 422
The charging means 43 is disposed in the charging means mounting space 412c, which is located at a position opposite to the lower peripheral surface of the photosensitive drum 42. The charging means 43 includes a charging corona discharger 431 serving as a charger disposed in parallel with the photoreceptor drum 42 along the axial direction, and a charger holding member made of synthetic resin for mounting and holding the charging corona discharger. Member 43
The charging device holding member 432 is fitted in the charging means mounting space 412c and is positioned at a predetermined position. The charging unit 43 configured as described above 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 its front and back surfaces are bonded to the conductive sheet member 442 and the ground member 444 with an appropriate adhesive. Have been. The conductive sheet member 4
A tongue is provided on the front end of the tongue 42, and 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 444 a of the ground member 444 is connected to the brush supporting member 44.
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 conductive sheet member 442, the ground member 444, and the conductive plate 447 form a body. 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 to obtain the desired quality. Therefore, 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.

At the upper end of the charger holding member 432, a fused toner scraping member 47 having substantially the same length as the length of the photosensitive drum 42 in the axial direction is mounted with an appropriate adhesive. The fused toner scraping member 47 is brought into contact with the peripheral surface of the photosensitive drum 42 between the foreign matter collecting brush 441 and the charging area 442, and removes the toner that has re-adhered to the peripheral surface of the photosensitive drum 42. It has a function of scraping and storing a part of the scraped toner. That is, the foreign matter collection brush 441 allows the photosensitive drum 4
Foreign matter such as paper powder attached to the peripheral surface of No. 2 is removed,
At this time, the foreign matter collecting brush 441 also removes a part of the residual toner attached to the peripheral surface of the photosensitive drum 42.
The toner removed by the foreign matter collecting brush 441 is accumulated in the foreign matter collecting brush 441, and the accumulated toner is rubbed on the peripheral surface of the photosensitive drum 42.
As a result, a silica component as a surface treatment agent for toner powder particles is fused to the peripheral surface of the photosensitive drum 42 in particular.
The toner fused to the peripheral surface of the photosensitive drum 42 is not removed in the next developing step, and the fused toner becomes a starting point and gradually grows by repeating the image forming operation.
So-called toner filming having a streak shape occurs, which adversely affects a transferred image thereafter. For this reason, it is desirable that the toner deposited on the foreign matter collecting brush 441 be scraped off at the time of the first fusion to the peripheral surface of the photosensitive drum 42 so as not to grow as toner filming. Therefore, it is important for the fused toner scraping member 47 to immediately scrape off the toner re-adhered to the peripheral surface of the photosensitive drum 42 on the downstream side, and that a part of the scraped-off toner adheres. Therefore, it is important to have a function of accommodating the attached toner.

In the illustrated embodiment, the fused toner scraping member 47 is formed of an open-cell foam (a so-called sponge) such as an open-cell polyurethane foam. It is important that the hardness of the fused toner scraping member 47 formed of the open-cell foam is within a predetermined range. That is, if the hardness of the open-cell foam constituting the fused toner scraping member 47 is low, the photosensitive drum 4
When the toner fused to the peripheral surface of No. 2 cannot be sufficiently scraped off and the hardness of the open-cell foam is increased, the scraping ability of the toner is improved, but the hardness of the open-cell foam is too high. Thus, there is a problem that the peripheral surface of the photosensitive drum 42 is damaged. According to experiments conducted by the present inventors, as shown in FIG. 3, when the hardness of the open-cell foam constituting the fused toner scraping member 47 is 100 kgf, a considerably large streak-like toner film is formed on the peripheral surface of the photosensitive drum 42. Occurs,
It was also found that even when the hardness of the open-cell foam was 120 kgf, dot-like toner filming occurred. And
It was found that when the hardness of the open-cell foam was 130 kgf or more, toner filming did not occur. On the other hand, when the hardness of the open-cell foam is 250 kgf,
No scratch was generated on the peripheral surface of No. 2, but it was also found that when the hardness of the open-cell foam was 260 kgf or more, a scratch was generated on the peripheral surface of the photosensitive drum 42. Therefore, the hardness of the open-cell foam constituting the fused toner scraping member 47 is desirably set to 130 kgf to 250 kgf. As the open-cell foam suitable for the fusing toner scraping member 47, "Everlite MP" (trade name) manufactured by Bridgestone Corp. having a hardness of 190 kgf can be used.

Further, since a part of the scraped toner adheres to the fused toner scraping member 47, it is important to have a function of accommodating the scraped toner in order to prevent the attached toner from scattering. is there. Fused toner scraping member 47
When the toner is caught beyond the toner storage capacity of the photosensitive drum 42, the scraping function is reduced, and the toner re-adhered to the peripheral surface of the photosensitive drum 42 cannot be scraped. The toner accommodating capacity of the fusing toner scraping member 47 increases as the porosity of the open-cell foam constituting the fusing toner scraping member 47 increases. Since the hardness of the open-cell foam decreases as the porosity increases, it is desirable to set the porosity within the above-mentioned usable hardness range.

The fusing toner scraping member 47 is made of an insulating material in the illustrated embodiment. Since the distance between the processes around the photosensitive drum 42 has been reduced due to the miniaturization of the apparatus, the fusion toner scraping member 47 is disposed at a position close to the charging corona discharger 431. . For this reason, if the fused toner scraping member 47 is formed of a conductive member, the charged charges may leak from the charging corona discharger 431, causing charging failure. Therefore, it is desirable that the fusing toner scraping member 47 be made of an insulating material.

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 photoreceptor support 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 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) and a left side wall 513, which are integrally formed of a synthetic resin and define a stirring chamber 514 and a developing chamber 515. A stirring chamber 51 is provided on a bottom wall 511 of the developing housing 51.
A partition wall 516 provided in the front-rear direction (the direction perpendicular to the paper surface in FIG. 2) between the developing chamber 4 and the developing chamber 515 is integrally formed. Both left and right surfaces of the partition wall 516 are formed on arcuate guide surfaces 516a and 516b. 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.
8 is fitted with a cap 519. At the upper end of the developing housing 51 on the side of the developing chamber 515, the support shaft 5 is provided so as to penetrate the front and rear side walls 512. The photosensitive unit 4 is provided at both ends of the support shaft 5.
A pair of side wall members 41 constituting the photosensitive member supporting means 41
By fitting the mounting holes 414 provided in the first support portion 413, the photoconductor unit 40 and the developing unit 50 are supported so as to be able to swing mutually. The photoconductor unit 4
0 and the developing housing 51
A coil spring 52 serving as a spring means is interposed between the front end and the rear end of the photosensitive member supporting means 41 and the developing housing 5.
Numerals 1 are urged to draw 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 replenishing 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 driven to rotate from the lower side to the upper side in a direction indicated by an arrow by a driving unit (not shown), that is, in a developing area which is a contact portion between the roller 532 and the photosensitive drum 42. The rotation of the rotation shaft 531 causes the roller 532 to rotate.
The roller 532 is also driven to rotate in the direction indicated 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 forming 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. The rotating shaft 541 of the replenishing roller 54 is rotated from the upper side to the lower side in a direction indicated by an arrow by a driving unit (not shown), that is, in a developer holding area 533 which is a nip portion between the roller 542 and the roller 532 of the developing roller 53. I'm sullen. Rotary axis 5
Due to the above rotation of the roller 41, the roller 542 is also driven to rotate in the direction shown by the arrow. In the illustrated embodiment,
The rotation shaft 541 of the supply roller 54 has the developing roller 53
A constant voltage of 450 V, which is higher than the applied voltage, is applied.

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. The stirring means 55 thus configured is continuously driven to rotate in a direction indicated by an arrow in FIG. 2 by a driving means (not shown).

The developer regulating means 56 is a regulating blade 5 made of a thin flexible 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 a 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 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 disposed 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 it is possible to obtain a sufficient operation and effect of alleviating the deformation of the regulating blade 561.

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.

The process unit 4 configured as described above is detachably mounted on the body housing 20 of the printer 2 as shown in FIG. That is, the upper part of the housing main body 21 constituting the body housing 20 is opened by turning the cover 23 constituting the body housing 20 of the printer 2 around the axis 22 counterclockwise in FIG. Next, the process unit 4 is mounted in the housing body 21 from above. The housing body 21
Inside, a positioning means (not shown) capable of mounting the photoconductor unit 40 of the process unit 4 at a predetermined position is provided. The process unit 4 is connected to the body housing 20.
When the cover 22 is attached to the housing body 21 of the
By turning clockwise in FIG. 1 around two directions, the upper part is closed.

As shown in FIG. 1, a lower part of a housing body 21 constituting a body housing 20 of the printer 2 is provided with:
A laser unit 24 is provided. 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. A fixing roller pair 25 is disposed on the downstream side of the post-transfer guide plate 46 on the housing body 21 constituting the body housing 20 of the printer 2, and a discharge roller pair 26 is disposed on the downstream side of the fixing roller pair 25. Are arranged. Further, a discharge tray 27 is provided downstream of the discharge roller pair 26.

A cover 23 constituting the body housing 20 of the printer 2 is provided with a paper feed tray 28 on which transfer paper is placed on the 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. When the removed residual toner accumulates on the foreign matter collecting brush 44, the accumulated toner rubs against the peripheral surface of the photosensitive drum 42, and as a result, is reattached to the peripheral surface of the photosensitive drum 42. When the toner re-adhered to the peripheral surface of the photosensitive drum 42 reaches the fusion toner scraping member 47, the fusion toner scraping member 4
7, and a part of the scraped toner adheres to the fused toner scraping member 47. However, most of the scraped toner adheres to the peripheral surface of the photosensitive drum 42 in a state where the fused state is removed. And is removed by the developing roller 53 in the developing process. On the other hand, a part of the toner attached to the fused toner scraping member 47 is stored in the pores of the open-cell foam constituting the fused toner scraping member 47.

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, 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. 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]

Since the image forming apparatus and the process unit used in the image forming apparatus according to the present invention are constructed as described above, the following operational effects can be obtained.

That is, according to the present invention, between the foreign matter collecting means provided between the transfer area and the charging area and the charging area, the foreign matter collecting means is disposed in contact with the peripheral surface of the photosensitive drum, and Since a fusing toner scraping member made of foam is provided, residual toner removed together with paper dust and the like adhered to the peripheral surface of the photosensitive drum by the foreign matter collecting means is rubbed against the peripheral surface of the photosensitive drum. Even if the toner is reattached, the reattached toner is immediately scraped off by the fusing toner scraping member, and is prevented from growing as toner filming. Therefore, it is possible to prevent the transfer image from being adversely affected by toner filming generated on the peripheral surface of the photosensitive drum.

[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 cross-sectional view of the image forming apparatus configured according to the present invention shown in FIG.

FIG. 3 is a diagram showing the hardness of an open-cell foam constituting a fused toner scraping member and the state of occurrence of toner filming and drum flaws.

[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: Ejection roller pair 27: Ejection ray 28: Feeding ray 29: Feeding roller Reference Signs List 30: friction pad 31: transfer roller 40: photoreceptor unit 41: photoreceptor support means 42: photoreceptor drum 43: charging means 44: foreign matter collecting means 45: guide plate pair before transfer 46: guide plate after transfer 47: fusion Toner scraping member 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: photosensitive member supporting means Side wall member 412: Connecting member of photoconductor supporting means 422: Charging area 423: Electrostatic latent image forming area 424: Developing area 4 5: transfer area 431: charging corona discharger 441: foreign matter collecting brush 442: conductive sealing member 443: elastic holding member 444: grounding member 445: brush supporting member 470: toner intrusion prevention wall 514: stirring chamber 515: developing chamber 517: connecting member of developing housing 533: developer holding area 534: developer controlling area 561: regulating blade 562: regulating member 566: fulcrum member

Claims (8)

[Claims] 1. A photosensitive drum rotatably disposed to sequentially pass through a charging area, an electrostatic latent image forming area, a developing area, and a transfer area, and a peripheral surface of the photosensitive drum disposed in the charging area. A charger for charging to a specific polarity; a developing device disposed in the developing area for developing an electrostatic latent image formed on the peripheral surface of the photosensitive drum in the electrostatic latent image forming area into a toner image; Transfer means disposed on the transfer area for transferring the toner image formed on the peripheral surface of the photosensitive drum to transfer paper; and contacting the peripheral surface of the photosensitive drum between the transfer area and the charging area. And a foreign matter collecting means for removing foreign matter attached to the peripheral surface of the photosensitive drum, wherein the foreign matter collecting means is disposed between the foreign matter collecting means and the charged area. Fused toner scraper arranged in contact and composed of open-cell foam Ri member equipped with a image forming apparatus, characterized in that. 2. The fusing toner scraping member made of an open-cell foam has a hardness of 130 to 250 k.
The image forming apparatus according to claim 1, wherein the value is set to gf. 3. The fusing toner scraping member made of an open-cell foam is made of an insulating material.
The image forming apparatus according to claim 1. 4. The image forming apparatus according to claim 1, wherein the fusing toner scraping member formed of an open-cell foam is made of a urethane foam. 5. A photosensitive drum rotatably disposed to sequentially pass through a charging area, an electrostatic latent image forming area, a developing area and a transfer area, and a peripheral surface of the photosensitive drum disposed in the charging area. A charger for charging to a specific polarity; a developing device disposed in the developing area for developing an electrostatic latent image formed on the peripheral surface of the photosensitive drum in the electrostatic latent image forming area into a toner image; Forming apparatus united with a foreign matter collecting means disposed between the charging area and the charging area in contact with the peripheral surface of the photosensitive drum and removing foreign matter attached to the peripheral surface of the photosensitive drum A unit that is provided between the foreign matter collecting means and the charged area in contact with the peripheral surface of the photoconductor drum, and is provided with a fusing toner scraping member made of an open-cell foam. Characteristic process unit of image forming machine. 6. The fusing toner scraping member formed of an open-cell foam has a hardness of 130 to 250 k.
The process unit of the image forming apparatus according to claim 5, wherein the process unit is set to gf. 7. The fusing toner scraping member made of an open-cell foam is made of an insulating material.
A process unit for the image forming apparatus according to claim 5. 8. The process unit of an image forming apparatus according to claim 5, wherein said fusing toner scraping member formed of an open-cell foam is made of a urethane foam.