KR19980018946A - IMAGE-FORMING MACHINE AND PHOTOSENSITIVE DRUM ADAPTED THERETO - Google Patents

Abstract

The image forming apparatus includes a photosensitive member unit 40 including a photosensitive member drum 42 and a photosensitive member supporting means 41 on which the photosensitive member drum is mounted, and the photosensitive member unit is mounted on the base frame 3 in which the optical unit is disposed. It is configured to be detachably mounted.

The photosensitive member unit 40 is configured to be directly supported by the photosensitive drum 42 when mounted on the base frame (3).

Description

Image Forming Machine and Photosensitive Drum

The present invention relates to an image forming apparatus for developing an electrostatic latent image formed on a photosensitive layer of a photosensitive drum such as a laser latent imager and a laser printer to a toner image, and transferring the toner image onto a transfer paper and a photosensitive drum applied thereto.

This type of image forming machine identifies a photosensitive drum that passes through the charging zone, the electrostatic latent image forming zone, the developing zone, and the transfer zone freely rotated, and the peripheral surface of the photosensitive drum disposed at the Daejeon zone. A charging device charged with the polarity of the polarizer, a developing device arranged in the developing zone for developing the electrostatic latent image formed on the peripheral surface of the photosensitive drum in the electrostatic latent image forming zone as a toner image; And transfer means for transferring the toner image onto the transfer paper.

In this type of image forming machine, the photosensitive drum is formed by a photosensitive member supporting means which supports the photosensitive drum freely in rotation so that the photosensitive drum can be easily replaced, and the photosensitive member unit is placed on the base frame where the optical unit is disposed. It is configured to be mounted and detachable.

In the image forming apparatus in which the photosensitive member unit is mounted and detachably mounted on the base frame as described above, the photosensitive drum must be positioned in a predetermined position relative to the optical unit disposed in the base frame when the photosensitive unit is mounted. There is.

Therefore, in order to accurately position the photosensitive drum in a predetermined position with respect to the optical unit installed in the base frame, the accuracy of the photosensitive unit as an assembly and the assembling precision of the photosensitive unit and the base frame are required.

SUMMARY OF THE INVENTION An object of the present invention is to securely position the photosensitive drum at a predetermined position by mounting the photosensitive unit to the base frame without increasing the assembly precision of the photosensitive unit and the assembly precision with the base frame more than necessary. An image forming machine and a photosensitive drum applied thereto are provided.

1 is a front view schematically showing one embodiment of an image forming machine constructed according to the present invention;

FIG. 2 is a sectional view of a process unit equipped with the image forming machine shown in FIG. 1; FIG.

3 is an essential part perspective view of a process unit equipped with the image forming apparatus shown in FIG. 2;

4 is an essential part perspective view of the base frame of the image forming machine shown in FIG. 1;

5 is a cross-sectional view taken along a line A-A in FIG. 1.

FIG. 6 is an enlarged cross-sectional view of the main part showing an engaged state of an annular groove formed in the support shaft of the photosensitive drum in FIG. 5 and an engagement paw1 of a flange attached to the drum body; FIG. .

* Explanation of symbols for the main parts of the drawings

3: Machin grame, 4: Process unit, 40: Photosensitive unit, 41: Photosensitive member support means, 42: Photosensitive drum, 60: Laser unit (optical system unit), 420: Drum body, 421: Photosensitive drum support Shaft, 34, 35: pressing member, 343: pressing member, 352a: shaft contact portion

As described above, in order to solve the main technical problem, in the present invention, the photoconductor unit including the photoconductor drum and the photoconductor support means on which the photoconductor drum is mounted can be attached to or detached from the base frame provided with the optical system unit. An image forming apparatus to be mounted is provided, wherein when the photosensitive member unit is mounted at a predetermined position of the base frame, the photosensitive drum is directly supported by the base frame.

The photosensitive drum includes a drum body and a support shaft which is rotatably supported in a state in which movement of the drum body in a predetermined position in an axial direction is restricted, and the photosensitive member supporting means is mounted. When mounted at a predetermined position of the base frame is configured to support the support shaft directly by the base frame.

The gas frame has a shaft support portion for supporting both ends of the support shaft, respectively, the shaft support portion is provided with a pressing member for pressing one end of the support shaft, and the other shaft support portion has the other end of the support shaft. The shaft contact part which makes the contact | abutment is provided.

One end of the drum body is equipped with a driven gear constituted by a spiral gear, the direction of the spiral tooth of the spiral gear is an inclination in which the thrust generated when driving is directed toward the shaft contact portion. It is formed in the direction.

The pressing member is made of a conductive material and has a grounding function of grounding the photosensitive drum.

In addition, according to the present invention, there is provided a photosensitive drum of an image forming machine constituting a photosensitive unit which is detachably attached to a base frame provided with an optical unit, and includes a drum body and a support shaft freely supporting the drum body. When the photosensitive member unit is mounted at a predetermined position of the base frame, the support shaft is directly supported by the base frame.

The support shaft supports the drum body freely in a state where the movement of the drum body from a predetermined position in the axial direction is restricted. When the photosensitive unit is mounted at a predetermined position of the base frame, the support shaft is directly supported by the base frame. It is configured to be.

At one end of the drum body, a driven gear driven by a helical gear is mounted, and the helical teeth of the helical gear are formed in an inclined direction in which thrust generated during driving acts toward the shaft contact portion.

Embodiment

EMBODIMENT OF THE INVENTION Below, with reference to an accompanying drawing, one Embodiment of the image forming machine comprised by this invention is described in detail.

In the illustrated embodiment, a printer is described as an image forming apparatus constructed in accordance with the present invention.

1 schematically shows an embodiment of a printer constructed in accordance with the present invention.

In this embodiment, the printer 2 is a small, low speed laser printer used as a printing device such as a word processor, and has a gas housing 20 formed of synthetic resin.

The gas housing 20 includes a housing body 21 in the form of a box having an open upper side, and a cover 23 freely mounted on a shaft 22 disposed above the housing body 21. .

The gas frame 3 is disposed in the housing body 21 of the gas housing 20 configured as described above.

The process unit 4 is freely attached to and detached from the base frame 3.

As shown in Fig. 2, the process unit 4 includes a photosensitive member unit 40 and a developing unit 50 supported by the support shaft 5 in the photosensitive member unit 40 so as to be able to swing.

The photoconductor unit 40 has a photoconductor support means 41, and the photoconductor support means 41 has a pair of sidewall members 411 arranged at intervals in the front-rear direction (only the inner sidewall members in FIG. 2). And connecting members 412a and 412b connecting the lower portions of the pair of side wall members 411 to each other.

The connecting members 412a and 412b are arranged in parallel with the inner surfaces facing each other to form a charging means mounting space 412c for arranging the charging means described later.

And, as shown in Fig. 5, the connecting members 412a and 412b do not reach the side wall member 411 immediately preceding the front end (right side in Fig. 5). Side wall member 411 is connected by a side connecting member 412d.

The charging means mounting space 412c described above is located opposite the charging zone, which will be described later.

The photoconductor support means 41 comprised in this way is integrally formed with the synthetic resin.

Support portions 413 provided with mounting holes 414 are provided at the upper ends of the pair of side wall members 411 constituting the photoconductor support means 41 on the developing unit 50 side.

The developing unit 510 is inserted into the mounting hole 414 provided in the supporting part 413 so that the supporting shaft 5 made of a metal rod placed in the developing housing, which will be described later, is inserted into the photosensitive member unit 40. And the developing unit 50 are supported to be able to swing with each other.

The photosensitive member unit 40 includes a photosensitive member drum 42 having a photosensitive layer formed on a circumferential surface thereof.

Hereinafter, the structure of the photosensitive drum 42 and the supporting structure of the photosensitive drum 42 will be described with reference to FIG. 5.

In the illustrated embodiment, the photosensitive member drum 42 includes a dream body 420 having a photosensitive layer mounted on a cylindrical body circumferential surface of aluminum, and a support shaft 421 rotatably supporting the drum body 420. have.

The drum body 420 is freely supported for rotation in a state in which movement in the axial direction is restricted at a predetermined position of the support shaft 421.

A driven gear 70 is attached to one end (right end in FIG. 5) of the drum body 420 constituting the photosensitive drum 42.

The driven gear 70 is made of a conductive synthetic resin, and includes a mounting portion 701, a helical gear portion 702, and an axial insertion hole 703. The mounting portion 701 has an inner end portion of the drum body 420. It is press-inserted into.

The helical gear 702 is formed in the inclined direction so that the thrust generated when driving acts toward the other end.

The flange 71 is attached to the other end (left end of FIG. 5) of the drum body 420 constituting the photosensitive drum 42.

The flange 71 is made of a conductive synthetic resin, and is composed of a mounting portion 711, a locking member 712, and a shaft insertion hole 713, and the mounting portion 711 is press-inserted at the other end of the drum body 420. It is.

In the photosensitive drum 42 configured as described above, the support shaft 421 is inserted through the driven gears 70 and the flange insertion holes 703 and 713 provided in the flange 71 at both ends thereof.

An annular groove 422 is provided at a predetermined position of the support shaft 421, and the engaging member 712 of the flange 71 is engaged with the annular groove 422.

The engagement state of the annular groove 422 and the locking member 712 is shown enlarged in Fig. 6. That is, the locking member 712 is formed in a triangular cross-section, the inclined surface (712a), ( 712b contacts the upper edges of the side surfaces 422a and 422b forming the ring-shaped groove 422, respectively, and the tip 712c of the locking member 712 formed in the triangular shape is the ring-shaped groove 422. It is comprised so that it may contact the bottom surface 422c which forms ().

Therefore, the drum body 420 constituting the photosensitive drum 42 is freely supported on the support shaft 421 in a state in which axial movement is restricted.

In this way, the support shaft 421 supporting the drum body 420 is slidably supported in the axial direction by a pair of side wall members 411 whose both ends constitute the photosensitive member support means 41.

A packing 72 made of felt or the like is disposed between the end face of the flange 71 attached to the other end of the drum body 420 and the side wall member 411 described above.

This packing 72 comes into contact with the end face of the flange 71 and acts as a frictional resistance against the rotation of the photosensitive drum 42.

For this reason, the rotational fluctuation of the photosensitive drum 42 driven by a gear can be suppressed.

In addition, the driven gear 70 is a direction indicated by an arrow in FIG. 2 by a drive gear to be described later, that is, a charging zone 422, an electrostatic latent image forming zone 423, and a developing zone ( 424) and rotationally driven to sequentially pass through the transfer zone 425.

The charging means mounting space 412c located in the charging zone 422 is provided with charging means 43 disposed to be opposed to the lower peripheral surface of the photosensitive drum 42.

The charging means 43 includes a charging corona discharger 431 as a charger that is disposed along the axial direction in parallel with the photosensitive drum 42, and a charger holding member 432 that is a synthetic resin for mounting and mounting the charging corona discharger. And a charger holding member 432 is fitted to the charging means mounting space 412c and positioned at a predetermined position.

Further, a foreign matter recovery brush 44 in contact with the peripheral surface of the photosensitive drum 42 is disposed between the charging zone 422 and the transfer zone 425 along the axial direction of the photosensitive drum 42.

The paper powder collecting brush 44 is made of acrylic fiber and has a length substantially equal to the axial length of the photosensitive drum 42. The paper powder collecting brush 44 is formed integrally with the charger holding member 432 to form the photosensitive drum 42. It is mounted to the brush support member 440 disposed along the axial direction of the.

In addition, an upper end of the charger holding member 432 approaches the peripheral surface of the photosensitive drum 42 between the charging corona discharger 431 disposed in the charging zone 422 and the foreign matter recovery brush 44. It protrudes so that it may be formed, and the toner penetration preventing wall 47 is comprised.

The toner penetration preventing wall 47 is attached to the circumferential surface of the photosensitive drum 42 so that the residual toner removed together with the foreign matter such as paper powder by the foreign matter recovery brush 44 is not caught in the foreign matter recovery brush 44. When falling without, it has a function to prevent the intrusion on the charging corona discharger 431.

Between the pair of side wall members 411 constituting the photoconductor support means 41, a transfer zone 425 on the circumferential surface of the photosensitive drum 42 is transferred between the transfer paper supplied and conveyed from the upper left side in FIG. A lower guide plate 451 constituting one of the pair of pre-transfer guide plates 45 to be guided toward the side is disposed, and the lower axis guide plate 451 is integrally formed on 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 (vertical direction of the paper in FIG. 2).

In addition, the lower guide plate 451 is formed with a plurality of reinforcing ribs 451b integrally spaced apart from each other in the longitudinal direction (vertical direction of the ground in FIG. 2), and this reinforcing rib 451b is described above. It is comprised so that the support shaft 5 may abut.

Accordingly, the lower guide plate 451 can prevent the reinforcing rib 451b from being bent in contact with the support shaft 5 even when the upper surface of the lower guide plate 451 tries to bend due to the pressing force applied thereto.

In addition, the lower guide plate 451 functions as a connecting member for connecting the upper portions of the pair of side wall members 411 constituting the photosensitive member supporting means 41, and the rigidity of the photosensitive member supporting means 41 is increased. It can be improved.

In the illustrated embodiment, since the lower guide plate 451 is integrally formed with the pair of side wall members 411, the pair of side walls is integrally formed with the pair of side wall members 411. The positional relationship with respect to the photosensitive drum 42 by which rotation is freely supported by the member 411 can be maintained with high precision.

Further, the lower guide plate 451 in the illustrated embodiment functions as a contact preventing member of the photosensitive drum 42 to the photosensitive layer when attaching and detaching the process unit 4 and the developing unit 50. It also functions as a contact preventing member to the developing roller, which will be described later, and also has a function of preventing the toner scattering from the surface of the developing roller to be attached to the transfer paper or the transfer path of the transfer paper.

Between the pair of side wall members 411 constituting the photosensitive member support means 41, a post-transfer guide plate 46 for guiding the transfer paper transferred from the transfer zone 425 to the fixing means, which will be described later, is disposed. The transfer plate 46 is integrally formed 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 photosensitive member supporting means 41 to each other, and can improve the rigidity of the photosensitive member supporting means 41. .

The post-transfer guide plate 46 in the illustrated embodiment can also function as a contact preventing member of the photosensitive drum 42 against the photosensitive layer when attaching and detaching the process unit 4.

Next, the above developing unit 50 as the electrostatic latent image developing apparatus will be described.

The developing unit 50 in the illustrated embodiment includes a developing housing 51 in which a developer as a one-component toner is accommodated.

The developing housing 51 has a bottom wall 511 and a front side wall 512a (see Fig. 3) formed by standing upright at the front and rear ends of the bottom wall 511 (the vertical end in the ground in Fig. 2) and the right side. The wall 512b and the left wall 513 are formed integrally with synthetic resins, and define the stirring chamber 514 and the developing chamber 515.

In the bottom wall 511 constituting the developing housing 51, a partition wall 516 provided in the front-back direction (vertical direction to the ground in FIG. 2) is integrally formed between the stirring chamber 514 and the developing chamber 515. It is.

The left and right surfaces of the partition wall 516 are formed of arc-shaped guide surfaces 516a and 516b.

Between the front and rear side walls 512 constituting the developing housing 51, a connecting member 2517 disposed on the upper side of the developing chamber 515 is provided and integrally formed on 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 into the toner supply hole 518.

The above-described support shaft 5 is disposed at the upper end portion of the developing housing 51 on the developing chamber 515 side through the front and rear side walls 512, and the photosensitive member is formed at both ends of the supporting shaft 5. The photoreceptor unit 40 and the developing unit 50 are mutually aligned by fitting the mounting holes 414 provided in the support part 413 of the pair of side wall members 511 constituting the photoreceptor support means 41 of the unit 40. Oscillation is possibly supported.

In addition, between the lower end of the photosensitive member support means 41 of the photosensitive member unit 40 and the lower end of the developing housing 51, a coil spring 52, which is a spring means, is fitted to the front end and the rear end, respectively. By 52, the photosensitive member support means 41 and the developing housing 51 are urged to attract each other with the support shaft 5 as a fulcrum.

The developing housing 51 is open above and to the right, that is, at the photosensitive member 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 disposed.

The developing roller 53 is disposed in the developing chamber 515 of the developing housing 51 and has a rotating shaft 531 freely rotatably mounted on the front and rear side walls 512 of the developing housing 51, and the rotating shaft ( And a solid synthetic rubber roller 532 fixed to the outer circumferential surface of 531.

The rotating shaft 531 may be formed of a suitable rapid material such as stainless steel.

The solid synthetic rubber roller 532 is made of a relatively flexible and conductive material, for example, a conductive solid synthetic rubber such as urethane rubber.

In the illustrated embodiment, the surface roughness of the circumferential surface of the solid synthetic rubber roller 532, 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 at about 10 ⁴ to 10 ⁹ Pa · cm.

Moreover, the roller hardness of the solid synthetic rubber roller 532 is set to 60-80 by Asuka-C hardness in embodiment shown.

The roller 2532 of the developing roller 53 configured as described above is exposed through the opening on the right side formed in the developing housing 51, and is positioned to face the photosensitive drum 42.

The peripheral surface of the roller 532 constituting the developing roller 53 is in pressure contact with the peripheral surface of the photosensitive drum 42 in the developing zone, and the roller 532 is in the pressure contacted nip portion. The peripheral surface of is slightly elastically compressed.

As shown in Fig. 3, the front end of the rotating shaft 531 of the developing roller 53 protrudes from the front wall 512a of the developing housing 251, and the driven gear 501 is mounted at this end. The drive gear, which will be described later, is rotated from the lower side to the upper side in the direction indicated by the arrow in FIG. 2, that is, the developing region which is the contact portion between the roller 532 and the photosensitive drum 42. FIG. .

In addition, the driven gear 501 is formed of a gear of a helical tooth.

Further, a power transmission bevel gear 502 rk is integrally formed inside the driven gear 501.

The roller 532 is also driven to rotate in the direction indicated by the arrow by the rotation of the rotary shaft 531, the peripheral surface of the roller 532 is a developer holding zone 533, a developer regulatory zone 534 and a developing zone Have 424 move one after the other.

In the illustrated embodiment, a constant voltage of 300 V is applied to the developing roller 531.

The replenishment roller 54 is disposed in parallel with the developing roller 53 in the developing chamber 515 of the developing housing 51, and the front and rear side walls 512 forming the developing housing 51 are described above. And a roller 542 fixed to the outer circumferential surface of the rotary shaft 541.

The rotating shaft 541 of the feed roller 54 can be formed of a suitable metal material such as stainless steel, similarly to the rotating shaft 531 of the developing roller 53.

The roller 542 is composed of foam such as foamed silicone or urethane.

The roller 542 is in pressure contact with the roller 532 of the developing roller 53 in the developer holding area 533 which is a nip part with the developing roller 53.

The hardness of the foam constituting the roller 542 of the feed roller 54 is considerably smaller than the hardness of the roller 532 constituting the developing roller 53 (for example, about 35 in Asuka-C hardness), It is preferable that the roller 542 is elastically compressed by about 0.1 to 0.6 mm in the nip region while the roller 542 is in pressure contact with the roller 532 of the developing roller 53.

The roller 542 is also conductive, and its volume resistance is set to about 10 ² to 10 ⁶ Pa · cm.

As shown in FIG. 3, the front end of the rotating shaft 541 of the replenishment roller 54 protrudes from the front wall 512a of the developing housing 51, and the driven gear 503 is attached to this end. The driven gear 503 is configured to engage with the power transmission bevel gear 502 described above.

Accordingly, the rotation shaft 541 of the replenishment roller 54 is driven to rotate from the lower side to the upper side in the direction of arrow direction, that is, in the developing region which is the contact portion between the roller 532 and the photosensitive drum 42. As shown in FIG.

Rotational driving from the upper side to the lower side in the direction indicated by the arrow to the driving means (not shown), that is, the developer holding area 533 which is the nip portion of the roller 542 and the roller 532 of the developing roller 53. do.

The roller 542 is also driven to rotate in the direction indicated by the arrow by the rotation of the rotation shaft 541.

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 replenishment roller 54.

The circumferential speed V1 of the photosensitive drum 42, the circumferential speed v2 of the developing roller 53, and the circumferential speed v3 of the supply roller 54 are set in a relationship of V1V2V3.

In the illustrated embodiment, the relationship between the circumference 슥 degree V1 of the photosensitive drum 42 and the circumference 슥 degree V2 of the developing roller 53 is set to 1.2 V 1 ≦ V 2 ≦ 2.5 V 1. The relationship between the circumferential speed V2 and the circumferential speed V3 of the replenishment roller 54 is set to 1.0 V 2 ≤ V 3 ≤ 2.0 V 2.

When the circumferential speed V2 of the developing roller 53 becomes 1.2 V1 or less, supply of the developer to the photosensitive drum 42 becomes insufficient, which causes a decrease in image density.

In addition, when the peripheral speed V2 of the developing roller 53 becomes 1.2 V1 or less, the scraping effect of the developing roller 53 with respect to the negative transfer developer attached to the photosensitive drum 42 after transfer decreases. This causes the so-called offset fogging caused by failure to remove from the photoreceptor drum 42.

On the other hand, when the circumferential speed V2 of the developing roller 53 becomes 2.5 V1 or more, the driving torque of the developing roller 53 increases, and at the same time, it causes scattering of the developer due to the centrifugal force.

Moreover, when the peripheral speed V3 of the replenishment roller 54 becomes 1.0 V2 or less, supply of the developer to the developing roller 53 will become insufficient, and it will cause a fall of image density.

When the circumferential speed V3 of the replenishment roller 254 becomes 1.0 V2 or less, the scraping action of the peripheral surface of the developing roller 53 by the replenishment roller 54 is weak. Therefore, it is attached to the photosensitive drum 42 after transfer. When the negative transfer developer adheres to the developing roller 53, it becomes difficult to remove the adhesion developer, which causes a so-called ghost phenomenon that appears in the next development.

On the other hand, when the circumferential speed V3 of the replenishment roller 54 becomes 2.0 V2 or more, the driving torque of the replenishment roller 54 increases, and at the same time, the developer is at the upper side of the nipple of the replenishment roller 54 and the developing roller 53. The tendency to stay in the film becomes stronger, which causes a shortage of developer supply to the developing roller 53.

The stirring means 55 is arrange | positioned in the stirring chamber 514 of said image development housing 51.

The stirring means 55 is disposed in parallel with the replenishment roller 54, the rotating shaft 551 is freely rotatably mounted on the front and rear side walls 512 of the developing housing 51, A stirring member 552 fixed to the rotary shaft 551 and an elastic stirring sheet member 553 attached to the stirring member 552 are included.

The stirring member 552 is formed of synthetic resin and has a plurality of openings in the longitudinal direction (the direction perpendicular to the ground in FIG. 2).

The stirring sheet member 553 is formed of, for example, a polyethylene terephthalate (PETP) resin having flexible elasticity and is fixed to the edge of the front end of the stirring member 552 with an adhesive or the like.

The end just in front of the rotating shaft 551 of the stirring means 55 configured as described above protrudes from the front wall 512a of the developing housing 51, and the driven gear 504 is disposed at this end. ) Is installed.

The driven gear 504 is a driven bevel gear 503 mounted to the rotating shaft 541 of the replenishing roller 54 and a power transmission gear freely rotatable to the front wall 512a of the developing housing 51. 505, 506, and 507 are coupled to transmit power.

Therefore, the stirring means 55 is continuously rotated in the direction indicated by the arrow in FIG.

The developer regulating means 56 includes a blade 561 having flexible elasticity that is in pressure contact with the circumferential surface of the roller 532 constituting the developing roller 32.

The blade 561 is made of, for example, a stainless steel sheet or a spring steel sheet having a thickness of about 0.1 to 0.2 mm, and has a lengthwise dimension substantially equal to the length of the roller 532 constituting the developing roller 53. have.

The blade 561 is attached to the blade mounting portion 51la provided at the end of the open portion on the photosensitive unit 40 side of the bottom wall 511 whose base end constitutes the developing housing 51.

In other words, the proximal end of the blade 561 is sandwiched and supported by the blade mounting portion 511a and the pressing plate 562, and is fixed by the biscrew 536.

The front end of the blade 561 is formed to be bent, and the bent part is configured to be in pressure contact with the circumferential surface of the roller 532 constituting the developing roller 53 in the developer regulatory region 534.

The developing housing 51 is equipped with a lid 57 covering the open top.

The lid 57 is made of synthetic resin, and is fixed to the upper surface of the front and rear walls 512 and the left wall 513 and the connecting member 517 constituting the developing housing 51.

On the inner surface of the lid 57, it is provided in the front and rear direction (perpendicular to the ground in FIG. 2) at a position opposite to the replenishment roller 54, and restricting portion 571 protruding toward the developing chamber 515 side. ) Is integrally formed.

Further, a predetermined interval is set between the lower end of the restricting portion 571 and the outer circumferential surface of the roller 542 constituting the above-mentioned supply roller 54.

In the illustrated embodiment, a sheet type sealing member 58 is attached to the connecting member 517 constituting the developing housing 51.

The sheet-type seal member 58 is composed of a sheet member having flexible elasticity, such as polyethylene terephthalate (PETP) resin, and the shaft of the roller 532 constituting the developing roller 53. It has almost the same length as the direction.

One end of the sheet-shaped seal member 58 is fixed to the connecting member 517 by fixing means such as an adhesive, and the other end thereof is bent (curved) of the roller 532 constituting the developing roller 53. Elastic contact with the circumferential surface.

The sheet-like seal member 58 configured as described above, together with the blade 561 of the developer regulating means 56, prevents the developer from scattering from the opening on the photosensitive member 40 side of the developing housing 51. .

The process unit 4 configured as described above is freely attached to or detached from the gas frame 3 disposed on the housing body 21 of the gas housing 20.

Next, the base frame 3 will be described with reference to FIGS. 1, 4 and 5.

The gas frame 3 is disposed in the housing body 21 of the gas housing 20 at the position where the process unit 4 is disposed.

The base frame 3 is made of synthetic resin, and has a bottom wall 31, a front side wall 32, and an inner side wall 33 as shown in FIG.

One side shaft support part 34 supporting one end of the support shaft 421 of the photosensitive drum 42 is provided on the side wall 32 on the front side of the base frame 3, and the inner side wall 33 is provided on the side wall 32. The other shaft support part 35 which supports the other end part of the support shaft 421 is provided.

One shaft support portion 34 provided on the side wall 32 on the front side of the base frame 3 is formed to be wider upward and connected to a guide groove 341 with an open top and a lower end of the guide groove 341. And a fitting groove 342 (bitting groove) having a width corresponding to the diameter of the support shaft 421.

The outer side wall constituting the guide groove 341 is formed with a guide surface 341a inclined from the upper end to the inner side.

In addition, the fitting member 343 formed by bending a conductive plate such as a spring steel sheet or a stainless steel sheet is disposed in the fitting groove portion 342.

The pressing member 343 functions as a grounding device for the photosensitive drum 42 and is provided on the front side wall 32 through the metal plate 344.

Further, the metal plate 344 is connected to a frame base 345 made of a metal plate whose lower end is attached to the bottom wall 31 constituting the base frame 3.

Accordingly, the photosensitive drum 42 has a frame base through a driven gear 70 and a flange 71 made of conductive synthetic resin, a support shaft 421 made of a metal rod material, a pressing member 343, and a metal plate 344. 345) body grounded.

The other shaft support portion 35 provided on the inner sidewall 33 of the base frame 3 is provided to be aligned with the one shaft support portion 34 provided on the side wall 32 of the front side, and the paper sheet is Like the branch portion 34, the guide groove portion 351 is formed to be wider upward and opened upward, and is connected to the lower end of the guide groove portion 351, and has a width corresponding to the diameter of the support shaft 421. The groove part 352 to be fitted is provided.

The outer side wall constituting the guide groove 351 is formed with a guide surface 351a inclined inward from the top, and the outer side wall constituting the fitting groove 352 is the guide surface 351a. It is formed continuously at the lower end of and serves as the shaft contact portion 352a.

On the side wall 32 of the front side of the base frame 3, when the support shaft 421 of the photosensitive drum 42 is mounted on the shaft supporting portions 34 and 35, one of the photosensitive drums 42 is used. The driven gear 70 mounted at the end and the drive gear 36 meshed with the other teeth are arranged.

Moreover, the drive gear 37 which engages with the driven gear 501 attached to the rotating shaft 531 of the said developing roller 53 by the foreign material is arrange | positioned at the side wall 32 of the front side of the base frame 3. .

The drive gears 36 and 37 are formed as spiral gears.

In addition, the drive gear 36 and the drive gear 37 are each configured to be driven through a suitable gear power transmission mechanism by a drive force of an electric motor (not shown).

The process unit 4 is mounted to the base frame 3 configured as described above as follows.

That is, the housing body 21 constituting the gas housing 20 by turning the cover 23 constituting the gas housing 20 of the printer 2 counterclockwise in FIG. 1 by turning the shaft 22. The upper side of is opened to expose the gas frame (3).

Subsequently, the process unit 4 is attached to the base frame 3 from above.

At this time, both ends of the support shaft 421 of the photosensitive drum 42 are inserted into the groove portions 342 and 352 which are guided and fitted into the guide grooves 341 and 351 of the shaft support portions 34 and 35. The support shaft 421 is directly supported by the base frame 3.

In this way, when the support shaft 421 is fitted into the grooves 342 and 352 to be fitted, the driven gear 70 mounted at one end of the drum body 420 constituting the photosensitive drum 42 is driven. The driven gear 501 mounted on the rotary shaft 531 of the developing roller 53 is engaged with the drive gear 37 by a foreign engagement.

Then, the support shaft 421 of the photosensitive drum 42 is pressed left and right in contact with the pressing member 343 as shown in Figure 5, the other end is in contact with the shaft contact portion 352a Stays in the state.

Therefore, the drum body 420 whose rotation is freely supported in the state in which the movement in the axial direction is restricted from the predetermined position on the support shaft 42l is reliably positioned at the predetermined position of the base frame 3.

In this way, when the process unit 4 is attached to the base frame 3 from above, the support shaft 421 of the photosensitive drum 42 is directly supported by the base frame 3, so that the assembly of the photosensitive unit 40 is assembled. The photosensitive drum 42 can be reliably positioned at a predetermined position without increasing the accuracy and the assembling precision of the base frame 3 more than necessary.

The gas 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. By means, the process unit 4 is mounted at a predetermined position of the base frame 3.

As described above, when the process unit 4 is mounted on the base frame 3, the upper part is closed while turning the cover 23 in the clockwise direction in FIG.

As shown in FIG. 1, a laser unit 60 as an optical unit is disposed on the bottom wall 31 of the base frame 3 disposed in the housing main body 21 constituting the base housing 20 of the printer 2. It is arranged.

The laser unit 60 connects the laser light corresponding to the printing data from the word processor, for example, to the printer 2 in the electrostatic latent image forming region 423 of the process unit 4. Irradiate the photosensitive layer to form an electrostatic latent image.

In the photosensitive drum 42 having the electrostatic latent image formed by the laser unit 60, the support shaft 421 is directly supported at a predetermined position of the base frame 3 as described above. Since the positional relationship with the laser unit 60 arranged at the predetermined position is securely maintained, the electrostatic latent image can be reliably formed at the predetermined position of the photosensitive drum 42.

In the housing body 21 constituting the gas housing 20 of the printer 2, a pair of fixing rollers 61 is disposed downstream of the post transfer guide plate 46, and the fixing roller pairs 61 are arranged. On the downstream side of), a pair of discharge rollers 62 is disposed.

Further, a discharge tray 63 is disposed downstream of the discharge roller pair 62.

In the cover 23 constituting the gas housing 20 of the printer 2, a paper feed tray 64 on which a transfer sheet is placed on the upper left side in FIG. 1 is disposed.

A paper feed roller 65 is disposed downstream of the paper feed tray 64, and the paper feed roller 65 is driven by rotation in the direction indicated by the arrow in FIG.

The paper separating friction pad 66 is disposed to face the paper feed roller 65.

In the transfer zone 422 described above, a non-contact transfer roller 67 is disposed facing the photosensitive drum 42.

In the embodiment shown, this transfer roller 67 is formed with electroconductive foam urethane, and rotation is supported by the cover 23 freely.

Transfer rollers 67 are provided at both ends thereof with a color (not shown) made of an insulating material such as a synthetic resin having an outer diameter larger than that of the transfer rollers 67, and these colors are in contact with the circumferential surface of the photosensitive drum 42. It is arranged.

Accordingly, the transfer roller 67 slides along with the rotation of the photosensitive drum 42 to move accordingly.

The clearance between the peripheral surface of the transfer roller 67 and the peripheral surface of the photosensitive drum 42 is set to about 0.5 mm.

For example, a constant current of 100 μA is applied to the transfer roller 67 configured as described above.

Moreover, the upper side guide plate 452 which comprises the other of the said pair before transfer guide plate 45 is arrange | positioned at the cover 23. As shown in FIG.

The printer 2 in the illustrated embodiment is configured as described above, and the operation thereof will be described below.

Each member starts operation by a printing command from a word processor or the like not shown, and the surface photosensitive layer of the photosensitive drum 42 is substantially uniformly uniform with a specific polarity by the charging corona discharger 43. It is charged.

Next, the laser light corresponding to the printing data from the word processor or the like is irradiated to the surface of the photosensitive layer of the charged photosensitive drum 42 by the laser unit 24 to form an electrostatic latent image.

The correction latent image formed on the photosensitive layer of the photosensitive drum 42 in this way is developed into a toner image by the developing action by the developing unit 50 described above.

The developing operation of the developing unit 50 will be described later in detail.

On the other hand, the transfer paper placed on the paper feed tray 64 is fed one by one by the action of the paper feed roller 65 and the friction pad 66.

Then, the transfer sheet is guided to the pre-transfer guide plate 45 and conveyed between the photosensitive drum 42 and the transfer roller 67, and the toner image formed on the photosensitive drum 42 is transferred to the surface thereof.

The transfer sheet on which the toner image has been transferred is guided to the guide plate 46 after transfer and conveyed to the fixing roller pair 61.

The transfer paper on which the toner image is heat-fixed by the fixing roller pair 61 is discharged onto the discharge tray 63 by the discharge roller pair 62.

On the other hand, the circumferential surface of the photosensitive drum 42 passing through the transfer zone 425 has foreign matters such as paper powder attached to the circumferential surface when the foreign matter recovery brush 44 passes through the foreign matter recovery brush 44. Is removed by

At this time, the remaining toner adhering to the peripheral surface of the photosensitive drum 42 together with the foreign matter such as paper powder is also removed.

The removed residual toner may fall without being caught by the foreign matter recovery brush 44 reliably.

If the dropped toner accumulates on the corona discharger 431 described above, it causes a charging failure. In the illustrated embodiment, the toner intrusion prevention wall 47 causes the toner to fall. Intrusion into the corona discharger 431 side is prevented.

Next, the developing operation of the developing unit 50 will be described.

By starting operation of the developing unit 50, the developing roller 53, the replenishing roller 54, and the stirring means 55 are rotated in the directions indicated by the arrows, respectively, to the driving means not shown.

As the stirring member 552 constituting the stirring means 55 and the stirring sheet member 553 rotate in the directions indicated by the arrows, the developer accommodated in the stirring chamber 514 is stirred while crossing the partition wall 516. The feed roller 54 is supplied into the developing chamber 515 from above.

At this time, the limiting portion 571 formed on the inner surface of the lid 57 is limited so that the amount of the developer supplied into the developing chamber 515 does not become excessive.

Thus, the developer supplied by the stirring means 55 rides on the roller 542 of the replenishment roller 54 to the nip portion of the developer holding area 533 of the roller 532 of the developing roller 53. Is returned.

Further, since the feed roller 54 and the developing roller 53 rotate in the same direction from the top to the bottom in the developer holding area 533 which is the nip portion as described above, the feed roller 54 in the feed roller 54 is developed. The supply of the developer to the developer can be sufficiently supplied to prevent the developer shortage.

Further, since the replenishment roller 54 and the developing roller 53 rotate in the same direction in the developer holding area 533 which is the nip portion as described above, it can be surely driven without requiring a large driving force.

As described above, the developer conveyed to the developer holding area 533 which is the nip portion of the supply roller 54 and the developing roller 53 is held on the circumferential surface of the roller 532 constituting the developing roller 53. It is conveyed toward the developer regulatory area 534.

At this time, since the supply roller 54 and the developing roller 53 rotate in the same direction from the upper side to the lower side together in the developer holding area 533 which is the nip portion as described above, the developer passes through both nip portions and the developing roller ( 53, it is conveyed to the shape control area 534 and the developing area 424, and is rubbed with each other when passing through the nip part, so that charging is sufficient.

Thus, the occurrence of so-called fogging is prevented.

In the developer regulating region 534, the blade 561 of the developer regulating means 56 acts on the developer held on the circumferential surface of the roller 532 of the developing roller 53, thereby The developer held on the circumferential surface is regulated by the required amount to form a thin layer.

Further, in the developer control region 534, the developer stipulated by the blade 561 of the developer control means 56, and the developer scraped off the bottom wall 511 of the developing housing 51, the supply roller 54 Since it is rotated in the direction of arrow direction, it does not stay and is conveyed along the guide surface 561 6b of the partition wall 516.

As described above, in the developer holding zone 533, the developer holding means 533 is held on the circumferential surface of the roller 532 constituting the developing roller 53, The developer formed in the thin layer by the action of the blade 561 is conveyed to the developing zone 424 in accordance with the rotation of the arrow direction.

In the developing zone 424, a developer is applied to the electrostatic latent image on the electrostatic photosensitive member disposed on the circumferential surface of the photosensitive member drum 42, and the electrostatic latent image is developed into a toner image.

For example, the electrostatic latent image has a non-image area charged at about +600 V and an image area charged at about +120 V, and causes toner as a developer to adhere to the image area (so-called reverse phenomenon).

The photosensitive drum 42 and the developing roller 53 are rotated and driven in the direction of the arrow in Fig. 2, and thus, the peripheral surface of the photosensitive drum 42 and the developing roller 53 are formed in the developing zone 424. The circumferential surfaces of the rollers 532 are moved together in the same direction from bottom to top.

Since the circumferential speed V2 of the roller 532 and the circumferential speed V1 of the photosensitive drum 42 are set to 1.2 V1 ≤ V2 ≤ 2.5 V1, the development sufficient for the developing zone 424 by the roller 532 of the developing roller 53. The developer once adhered to the non-image portion of the electrostatic latent image is appropriately peeled off by the frictional action of the peripheral surface of the roller 532 against the peripheral surface of the photosensitive drum 42 while being conveyed.

Thus, a good toner image having an appropriate development concentration and no blur can be obtained.

On the other hand, the used developer which is held on the circumferential surface of the roller 532 constituting the developing roller 53 and has passed through the developing zone 424 is supplied from the nipple portion between the developing roller 53 and the supply roller 54. It is moved to the surface of the roller 54.

In addition, since the peripheral speed of the supply roller 54 is set larger than the peripheral speed of the developing roller 53, in order to move the developer in the nip part, it is attached to the developing roller 53 when passing through the developing zone 424. It can weaken the adhesive force of the negative transfer developer and recover it.

Therefore, it is possible to prevent the occurrence of so-called high ghosts caused by the negative transfer developer adhering to the developing roller 53.

In addition, as in the illustrated embodiment, the photosensitive drum 42 and the developing roller 53 are operated under pressure contact so that the peripheral speed V1 of the photosensitive drum 42 is smaller than the peripheral speed V2 of the developing roller 53. In this case, the photosensitive drum 42 has a braking action in driving the photosensitive drum 42 and the developing roller 53.

Therefore, the direction of the helical teeth of the driven gear 70 mounted on the photosensitive drum 42 and the driven gear 501 mounted on the rotation shaft 531 of the developing roller 53 is the driving force generated when driving together. It is formed in the opposite direction to each other in the inclined direction to act inward.

As mentioned above, although this invention was demonstrated by embodiment applied to the printer, this invention is not limited to embodiment shown in figure, For example, it can be applied to an electrostatic copying machine, and various modifications which do not deviate from the technical idea of this invention are carried out. Or modifications are possible.

The image forming apparatus according to the present invention and the photosensitive drum applied thereto have the following effects.

That is, according to the present invention, the photoconductor unit including the photoconductor drum and the photoconductor support means on which the photoconductor drum is mounted is mounted on the base frame, so that the photosensitive drum is directly supported on the base frame, so that the assembly precision of the photosensitive unit and the assembly of the base frame are It is possible to reliably position the photosensitive drum at a predetermined position without increasing the accuracy more than necessary.

Therefore, since the positional relationship of the optical system units arranged at the predetermined position of the base frame can be reliably maintained, the electrostatic latent image can be reliably formed at the predetermined position of the photosensitive drum.

Further, according to the present invention, the photosensitive drum includes a support shaft freely rotatable in a state where the movement of the drum body and the drum body from a predetermined position in an axial direction is restricted and mounted on the photosensitive member supporting means. When the unit is mounted at the predetermined position of the base frame, the support shaft is configured to be directly supported by the base frame, so that the axial positional relationship of the photosensitive drum is maintained.

Further, according to the present invention, the base frame includes shaft support portions for supporting both ends of the support shaft, and one shaft support portion is provided with a pressing member for pressing one end of the support shaft, and the other paper sheet is supported. Since the branch portion is provided with a shaft contact portion for bringing the other end of the support shaft into contact, the support shaft of the photosensitive drum is reliably supported at a predetermined position of the base frame.

According to the present invention, a driven gear composed of a spiral gear is mounted at one end of the photosensitive drum, and the direction of the spiral tooth of the spiral gear is inclined such that the thrust generated during driving is directed toward the shaft contact portion. Since the support shaft supporting the photosensitive drum and the driven gear is pressed in the direction in which the other end is in contact with the shaft contact portion during operation of the photosensitive drum, the other end is in contact with the shaft contact portion. Is definitely maintained.

Further, according to the present invention, since the pressing member is made of a conductive material and has a grounding function for grounding the photosensitive drum, it is not necessary to arrange the grounding member separately, so that the whole apparatus can be manufactured at low cost. .

Claims (8)

The photoreceptor unit 40 including the photoreceptor drum 42 and the photoreceptor support means 41 on which the photoreceptor drum is mounted is mounted on and detached from the base frame 3 on which the optical system unit (laser unit 60) is disposed. And an image forming unit (40) configured to be supported directly on the base frame when the photosensitive unit (40) is mounted at a predetermined position of the base frame (3). The method of claim 1, wherein the photosensitive drum (42) rotatably supports the drum body (420) and the drum body in a state in which movement in a axial direction from a predetermined position is restricted, and the photosensitive member supporting means ( 41 is provided with a support shaft 421, characterized in that the support shaft 421 is configured to be directly supported on the base frame when the photosensitive member unit 40 is mounted at a predetermined position of the base frame (3) Image forming machine. 3. The gas frame (3) according to claim 2, wherein the base frame (3) has shaft supports (34, 35) for supporting both ends of the support shaft, and one shaft support portion has a pressing member for pressing one end of the support shaft ( 343, and the other shaft support portion is provided with a shaft contact portion 352a for abutting the other end of the support shaft. 4. A driven gear composed of a helical tooth gear is mounted at one end of the drum body, and the direction of the helical tooth of the helical tooth gear is driven by the thrust generated when driving. And an inclined direction acting toward 352a. 4. An image forming apparatus according to claim 3, wherein said pressing member (343) is made of a conductive material and has a grounding function for grounding the photosensitive drum (42). A drum body and its drum body, which are photosensitive drums 42 of an image forming machine constituting a photosensitive member unit 40 that can be mounted and detached to a base frame 3 on which an optical system unit (laser unit 60) is disposed. And a support shaft freely rotatable, wherein the support shaft is configured to be directly supported by the body frame when the photosensitive member unit is mounted at a predetermined position of the body frame (3). 7. The support shaft according to claim 6, wherein the support shaft supports the drum body freely in a state in which the movement of the drum body from the predetermined position in the axial direction is restricted, and the photosensitive member unit 40 is mounted at the predetermined position of the base frame 3. And the support shaft 421 is directly supported by the base frame. 8. The driving gear according to claim 7, wherein a driven gear composed of a helical tooth gear is mounted at one end of the drum body, and the direction of the helical tooth of the helical gear gear is an inclined direction in which a thrust generated when driving acts toward the shaft contact portion. The photoconductive drum of the image forming machine, characterized in that formed.