JP2002341728A - Process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably keep a gap between a photoreceptor drum 7 and a processing means acting on the drum 7. SOLUTION: In this process cartridge attachable to/detachable from the image forming device having a drum frame for supporting the photoreceptor drum 7 and an electrifying frame 13 for supporting an electrifying means acting on the drum 7, a compression coil spring 30b energizing the electrifying means in a direction where it gets away from the drum 7 is provided between the drum frame and the electrifying frame 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge detachable from a main body of an electrophotographic image forming apparatus and an image forming apparatus having the same.

Here, an electrophotographic image forming apparatus (hereinafter simply referred to as an image forming apparatus) forms an image on a recording medium by using an electrophotographic image forming method. Examples of the image forming apparatus include a copying machine, a laser printer, an LED printer, a facsimile machine, a word processor, and the like.

Further, a process cartridge includes an image bearing member and process means (charging means,
(Developing means or cleaning means) are integrally formed as a cartridge, and this cartridge is made detachable from the image forming apparatus main body. Alternatively, the image bearing member and at least one of the process means acting on the image bearing member are integrally formed as a cartridge so as to be detachable from the image forming apparatus main body. Further, the image carrier and at least the developing means are integrally formed as a cartridge so as to be detachable from the image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image process, a cartridge is integrally formed with an image carrier and process means acting on the image carrier, and this cartridge is attached to and detached from the main body of the image forming apparatus. A process cartridge system that makes it possible is employed. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a serviceman, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

As a charging method, a contact charging method has hitherto been put to practical use. Among them, a roller charging method using a conductive roller as a charging member is particularly used. In the roller charging, a conductive elastic roller is brought into pressure contact with the photosensitive drum, and a voltage is applied thereto to charge the photosensitive drum.

[0006] However, in the contact charging method,
Since the essential charging mechanism uses a discharge phenomenon from the charging member to the photosensitive drum, the voltage required for charging needs to be a value equal to or higher than the surface potential of the photosensitive drum,
When AC charging is performed for uniform charging, problems such as vibration of the charging member and the photosensitive drum due to the electric field of the AC voltage, generation of noise (AC charging noise), and deterioration of the surface of the photosensitive drum due to electric discharge. Etc. became remarkable, and it became a new problem.

In view of this, a magnetic brush method has been devised in which a charge injection layer is provided on the surface of the photosensitive drum and charges are injected by a contact charging member. For this reason, sufficient charging can be performed in a short charging time, and the problems caused by the discharge have been solved. Specifically, it has a magnetic brush portion formed by magnetically restraining conductive magnetic particles as a charging member. The magnetic brush member for bringing the magnetic brush part into contact with the photoreceptor drum allows a large contact nip with the photoreceptor drum and uniform contact with the photoreceptor drum surface with no microscopic charging failure It is preferably used.

In the magnetic brush system, in order to make uniform contact of the magnetic brush with the photosensitive drum, a minute gap between the carrying member and the photosensitive drum is formed at both ends of the carrying member having the magnetic brush portion formed on the surface. A small gap holding member is provided. The small gap holding member is rotatably engaged with the magnetic brush holding member, and urges the charging means with an elastic member such as a compression coil spring to abut against the surface of the photosensitive drum with a predetermined load to make contact therewith. To stably maintain the minute gap.

As described above, as a configuration of a process cartridge utilizing a charging method of an object to be charged by direct injection of electric charge (injection charging method), a developing frame incorporating a developing roller and a developing blade and a toner as a developer are used. A type in which a frame supporting a charging unit is rotatably connected to a frame that integrally stores a stored toner frame and a photosensitive drum has been awarded.

The driving of the charging means of the magnetic brush type is transmitted from the driving means of the main body of the image forming apparatus to a drive receiving portion of the charging means provided at one end in the longitudinal direction. At this time, the input driving rotation direction is such that the magnetic brush holding member of the charging means is urged toward the photoreceptor drum around the support center rotatably engaging the frame supporting the charging means. The direction is set.

[0011]

However, in the above construction, both ends of the magnetic brush holding member of the charging means are actuated by the urging force of both the elastic member such as a compression coil spring and the driving rotational force from inside the image forming apparatus main body. Is urged to the photosensitive drum via the minute gap holding member disposed in the section, but the urging force due to the driving rotational force is not evenly distributed to the minute gap holding members at both ends, and receives the drive input. Many are added to the end side. For this reason, the balance of the urging force to the photosensitive drum at both ends in the longitudinal direction of the minute gap holding member is not uniform because one end receiving the drive input becomes large.

Further, the urging force at one end on the drive input side exerts an urging force more than necessary to stably maintain the minute gap, and the minute gap holding member is deformed to change the minute gap, or the magnetic brush holding There is a possibility that a fine gap may be changed by abrasion of a rotary sliding portion with the member or a contact portion with the photosensitive drum, and good charging may not be performed. In addition, the driving torque of the magnetic brush holding member and the photosensitive drum may be increased due to the shaving of the rotary sliding portion, and the load on the driving portion may increase.

Accordingly, an object of the present invention is to stably maintain a gap between an image carrier and a process means acting on the image carrier.

[0014]

To achieve the above object, a typical configuration of the present invention is a first configuration for supporting an image bearing member.
In a process cartridge detachable from an image forming apparatus having a frame and a second frame supporting a process unit acting on the image carrier, the process unit is provided between the first frame and the second frame. The image forming apparatus further includes an urging unit that urges the image carrier away from the image carrier.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings. In the following description, the longitudinal direction refers to a direction that intersects the transport direction of the recording medium and is parallel to the recording medium. In addition, the left and right refer to the left and right in the transport direction of the recording medium. Further, “above the process cartridge” means above the process cartridge in the mounted state.

(Schematic Configuration of Image Forming Apparatus) As shown in FIG. 1, this image forming apparatus uses an image forming a toner image on a photosensitive drum 7 (7Y, 7M, 7C, 7Bk) as an image carrier. Forming part 31 (31Y, 31M, 31C, 31Bk);
A transfer belt 4a for temporarily transferring the toner image, a secondary transfer roller 15 as a secondary transfer means for transferring the toner image on the belt 4a to the recording medium 2, and a transfer belt 4a and the secondary transfer roller 15 for transferring the recording medium 2 to the transfer belt 4a. Feeding means 3 for feeding the recording medium 2 to the transfer portion of the intermediate transfer means 4, fixing means 5 for fixing the transferred toner image on the recording medium, and discharging means for discharging the recording medium outside the machine Is provided.

(Operation of Image Forming Apparatus) As shown in FIG. 1, a feed cassette 3a for loading and storing a plurality of recording media (for example, recording paper, OHP sheet, cloth, etc.) 2 is attached to and detached from the image forming apparatus. It is freely attached. The recording medium 2 fed from the feeding cassette 3a by the pickup roller 3b is separated one by one by a pair of retard rollers 3c, and the registration roller pair 3 is separated by conveyance rollers 3d and 3f.
g.

When the recording medium 2 is conveyed, the registration roller pair 3g stops rotating, and the recording medium 2 is corrected for skew by hitting the nip.

In the case of the four-drum full-color system, the process cartridge B (BY, BM, BC, BB) including the photosensitive drum 7 has yellow Y, magenta M,
Four of cyan C and black Bk are arranged in parallel.
The optical scanning system 1 (1Y, 1M, 1C, 1B) is provided for each process cartridge BY, BM, BC, BB.
k) is provided, and after a toner image is formed on the photosensitive drum 7 (7Y, 7M, 7C, 7Bk) for each color by an image signal, the transfer roller 4 (4Y, 4M, 4C, 4B) is formed.
By k), the toners of the respective colors are superimposedly transferred onto the transfer belt 4a running in the direction of the arrow shown in the figure.

Thereafter, the recording medium 2 is sent out to the secondary transfer roller 15 at a predetermined timing, the toner image on the transfer belt 4a is transferred onto the recording medium, and is fixed by the fixing unit 5, and then is discharged. The sheets are discharged by pairs 3h and 3i and stacked on the tray 6 on the apparatus main body 14.

The image forming unit 31 (31Y, 31M, 31C, 31
Bk is the process cartridge B (BY, BM, B) except for the optical scanning system 1 (1Y, 1M, 1C, 1Bk).
C, BB).

(Overall Configuration of Process Cartridge) FIG.
As shown in (1), the process cartridge B includes a photosensitive drum 7, and process means (charging means, exposure unit, developing means) acting on the photosensitive drum 7 around the photosensitive drum 7.
A transfer opening is provided.

(Photosensitive Drum) In this embodiment, a two-component developer (toner) having a magnetic carrier powder is used as a developer. Therefore, as the photoconductor drum 7 used in the embodiment of the present invention, a commonly used organic photoconductor can be used. However, preferably,
When an organic photoreceptor having a surface layer having a material having a resistance of 10 ² to 10 ¹⁴ Ω · cm or an amorphous silicon photoreceptor is used, charge injection charging can be realized, and ozone generation can be prevented and consumption can be reduced. It is effective in reducing power.
Further, the chargeability can be improved.
Therefore, in the present embodiment, the photosensitive drum 7 in which a negatively charged organic photosensitive body is provided on an aluminum drum base is used.
Was used.

(Charging Means) The charging means is a magnetic brush charger 8 using a magnetic carrier. The charger 8 has a fixed magnet 8b and a regulating blade 8c arranged in a hollow cylindrical charging roller 8a rotatably supported.
After the transfer, the toner remaining on the photosensitive drum 7 is taken into the charger 8 which rotates in the direction of the arrow shown in the figure.

(Developing Means) In the present embodiment, the developing means 10 employs a method of developing a two-component developer in a contact state (two-component non-contact development). FIG. 2 shows the developing means 10 for two-component magnetic brush development used in the present embodiment.

The developing means 10 includes a developing container 10a to which toner is supplied, and a plurality of agitating screws 10 as a plurality of agitating and conveying members for agitating and conveying the toner in the developing container 10a.
g and 10h, and a developing roller 10d as a developer carrier for holding a predetermined amount of toner in the developing container 10a.

The developing roller 10d has a hollow cylindrical shape and is rotatably supported. A fixed magnet 10c is provided in the developing roller 10d. The developing roller 10d rotates in the same direction as the photosensitive drum 7, and the peripheral surface moves in a direction opposite to the moving direction of the peripheral surface of the photosensitive drum 7. The photosensitive drum 7 and the developing roller 10d are in non-contact with each other and have a thickness of 0.2 to 1.0 mm.
Gap is provided, and the toner is
It is set so that development can be performed in a state of contact with.

The toner mixed with the carrier is supplied by stirring screws 10g and 10h in a casing partitioned by a longitudinal partition wall 10f excluding both ends. A toner supply container TO (TOY, TOY, TO
M, TOC, TOB) (see FIG. 1), while being fed in one direction in the longitudinal direction of the stirring screw 10g, is stirred and passes through the portion without the partition wall 10f at the other end, and the stirring screw 10h. After being moved to one end side, it is then stirred and circulated by a stirring screw 10g while passing through a portion without the partition wall 10f on one end side.

(Operation of Process Cartridge at the Time of Image Forming) Here, a developing step of visualizing the electrostatic latent image formed on the photosensitive drum 7 by a two-component magnetic brush method using a developing means, and toner The impact ring system will be described below.

First, toner conveyed by the magnet 10c with the rotation of the developing roller 10d is regulated by a regulating blade 10e arranged perpendicular to the developing roller 10d in the process of being conveyed. A thin layer is formed thereon. When the thin-layered toner is conveyed to the main developing pole, ears are formed by magnetic force. The electrostatic latent image on the photosensitive drum 7 is developed by the spike-shaped toner, and then the toner on the developing sleeve 10d is returned to the developing container 10a by the repulsive magnetic field.

A DC voltage and an AC voltage are applied to the developing roller 10d from a power source (not shown). In general, in the two-component developing method, when an AC voltage is applied, the developing efficiency is increased, and the quality of an image is high. On the contrary, fogging is liable to occur. For this reason, usually, by providing a potential difference between the DC voltage applied to the developing roller 10d and the surface potential of the photosensitive drum 7, it is possible to prevent toner from adhering to the non-image area during development.

This toner image is then transferred to the transfer belt 4a by the intermediate transfer means 40. The intermediate transfer means 40 transfers the endless transfer belt 4a to the driving roller 4b and the driven roller 4b.
c and the secondary transfer facing roller 4d, and is rotated in the direction of the arrow in FIG. Further, transfer rollers 4 (4Y, 4M, 4C, 4Bk) are provided in the transfer belt 4a, and each transfer roller is supplied with power from a high-voltage power supply while generating a pressing force from the inside of the belt 4a toward the photosensitive drum 7. As a result, the toner image on the photosensitive drum 7 is sequentially transferred to the upper surface of the transfer belt 4a by performing charging of the opposite polarity to the toner from the back side of the transfer belt 4a.

As the transfer belt 4a, a belt made of a polyimide resin can be used. The material of the transfer belt 4a is not limited to a polyimide resin, but may be a dielectric such as a polycarbonate resin, a polyethylene terephthalate resin, a polyvinylidene fluoride resin, a polyethylene naphthalate resin, a polyether ether ketone resin, a polyether sulfone resin, A plastic such as a polyurethane resin or a fluorine-based or silicon-based rubber can be suitably used.

Transfer residual toner remains on the surface of the photosensitive drum 7 after the transfer of the toner image. When the transfer residual toner is passed through the magnetic brush charger 8 as it is, the charging potential of only the remaining image portion decreases, or the previous image portion becomes thin or dark on the next image (hereinafter, referred to as ghost). Will occur. Even if the transfer residual toner passes under the charged magnetic brush in contact with the photosensitive drum 7, the shape of the previous image remains in most cases. Therefore, it is necessary to take in the transfer residual toner that has reached the charged area into the magnetic brush charger 8 with the rotation of the photosensitive drum 7 and erase the history of the pre-image. Here, the transfer residual toner on the photosensitive drum 7 often has both positive and negative polarities due to peeling discharge at the time of transfer, but the toner is easily taken into the magnetic brush charger 8. In consideration of this, it is desirable that the transfer residual toner is positively charged.

In this embodiment, the photosensitive drum 7 between the intermediate transfer means 40 and the magnetic brush charger 8 is provided with a conductive brush.
11 are brought into contact with each other, and a bias having a polarity opposite to that of the charging bias is applied. Positive transfer residual toner passes through the magnetic brush charger 8, and negative transfer residual toner is temporarily transferred to the conductive brush 11.
And is sent out onto the photosensitive drum 7 again after the charge is removed. Thereby, the transfer residual toner is more easily taken in the direction of the magnetic brush.

(Structure of Process Cartridge Frame) This process cartridge B uses the electrophotographic photosensitive drum 7 and developing means as a developing frame as a second frame.
A charging roller 8a, a regulating blade 8c, a conductive brush 11 and the like are attached to a developing unit D integrally formed by
Each unit is assembled as an integral charging unit C with the charging frame 13 as a frame. Further, the developing unit D and the charging unit C are positioned and coupled by a front cover 16 and a rear cover 17 (see FIG. 4) from both ends in the longitudinal direction.

A shutter may be provided between the developing frame 12 and the charging frame 13 to protect the photosensitive drum 7 from external light or the like by closing the process cartridge B when the process cartridge B is removed outside the machine. .

FIGS. 3 to 7 are projection views of the process cartridge B. FIG. 3 is a front view, FIG. 4 is a right side view,
5 is a left side view, FIG. 6 is a plan view, and FIG. 7 is a rear view.
8 to 10 are external perspective views of the process cartridge B. Here, FIG. 8 is a perspective view as viewed obliquely from the front, and FIG.
Is a perspective view seen from the rear oblique direction, and FIG. 10 is a perspective view seen from the rear oblique direction with the side serving as the bottom view facing upward.

As shown in FIG. 2, the charging unit C comprises a charging roller 8a, a regulating blade 8c, and a conductive brush 11 integrally formed by a charging frame 13. 2, 4,
As shown in FIGS. 8, 9, and 10, the charging frame 13 forms a part of the exterior of the process cartridge B. The lower edge 13a of the charging frame 13 is parallel to the photosensitive drum 7 in the longitudinal direction at a distance close to the photosensitive drum 7 as shown in FIGS. The upper and lower walls 13b are substantially vertical so as to form the exterior of the process cartridge B from the lower edge 13a.
It has a top plate 13d in a direction substantially horizontal from the corner 13c, and is substantially key-shaped in cross section. A space below the top plate 13d is a space, and member mounting portions 13e and 13f are integrally formed at both ends in the longitudinal direction. Is molded.

FIG. 11 is a side view of the charging unit C viewed from the inside. Process cartridge B of charging frame 13
A charging roller bearing 22 and an end cover 23 are screwed together at one end on the near side in the mounting direction (to be mounted from the front of the apparatus body 14 in the longitudinal direction). A gear unit 24 is screwed and fixed to the other end.

FIG. 12 shows the regulating blade 8 of the charging unit C.
It is a side view which removes c and its supporting metal plate 8d, and is seen from the inside. A seat 13g for mounting a blade with the side surfaces of the member mounting portions 13e and 13f raised in steps is provided with a female screw 13h and a dowel 13i on a plane contacting both ends of the regulating blade 8c.
A sealing material 21g, such as a sponge, is attached in the longitudinal direction to a plane retreated from the seat 13g.

In order to prevent toner from leaking to the outside in the axial direction along the circumferential direction of the seal portions 8a1 at both ends of the charging roller 8a, a seal material 21b such as felt is attached. Therefore, portions of the charging frame 13 opposite to the seal portions 8a1 at both ends of the charging roller 8a are arc-shaped with the same center as the charging roller 8a.

The metal regulating blade 8c is spaced from the charging roller 8a as shown in FIG.
Is fixed to the supporting metal plate 8d. Support sheet metal 8d
Has a groove-shaped cross section and has a dowel 13 on a seat 13g of the charging frame 13.
i, and the small screw 8k is screwed into the female screw 13h of the seat 13g by passing through the hole of the support metal 8d so that the support metal 8d and the seat 13g come into contact with each other and the sealing material
21a is compressed by the supporting metal plate 8d. In addition, the vicinity of the seat 13g of the sealing material 21b is compressed by the supporting metal plate 8d. The supporting metal plate 8 d has extremely high rigidity, and the charging frame 13 is stiffened by fixing both ends to the charging frame 13. The member mounting portions 13e and 13f are provided on the back side of the support plate 8d.
A back member 25 (see FIG. 12) extending in the longitudinal direction is disposed therebetween, and is fixed to the supporting metal plate 8d.

(Mounting of Charging Unit) Charging Unit C
Is a developing frame which can swing the swing center SC shown in FIG.
Supported by 12. For this reason, as shown in FIG.
In the gear case 26 of the gear unit 24 fixed to one end on the far side in the longitudinal direction of the charging frame 13, a cylindrical shaft portion 26a is provided on the swing center SC, and the end cover 23 at the other end in the longitudinal direction is provided. Is provided with a cylindrical hole 23a on the swing center SC.

As shown in FIG. 2, the developing frame 12 accommodates the stirring screws 10g and 10h on both sides of the partition 10f, and also has a seat 12 for mounting the regulating blade 10e.
e, a side portion 12g forming an exterior portion on the left side when viewed from the mounting direction of the process cartridge B, and an end plate portion 12h at both ends in the longitudinal direction as shown in FIGS.
(Rear side) and 12i (front side).

The one end plate portion 12h has a hole 12j for allowing the cylindrical shaft portion 26a of the charging unit C to be rotatable via a bearing. The other end plate 12i has a charging frame
A hole 12m having the same diameter as the thirteen holes 23a is provided.

Therefore, a hole in the end plate 12h of the developing frame 12 is provided.
With the cylindrical shaft portion 26a of the charging unit C inserted into 12j, the cylindrical fitting hole of the charging unit C is aligned with the hole 12m of the end plate portion 12i of the developing frame 12. When the rear cover 17 on the rear side when viewed from the mounting direction of the process cartridge B is aligned with the end of the developing frame 12, a hollow cylindrical shaft protruding in the longitudinal direction on the inner side of the rear cover 17. The outer circumference of the support 17a (see FIGS. 11 and 15) fits into the hole 12j of the developing frame 12, and the inner circumference fits into the cylindrical shaft 26a of the charging unit C.

A support shaft 27 which fits and protrudes into a hole 12m provided in the end plate portion 12i of the developing frame 12 (FIGS. 11 and 1).
4), and fits into the hole 23a of the charging unit C. Thus, the charging unit C has a cylindrical shaft portion 26a on one end side rotatably supported by the rear cover 17 and a hole 23a on the other end side.
Are rotatably supported by the developing frame 12.

As shown in FIG. 2, FIG. 6, and FIG. 8, the upper part of the developing frame 12 is inside the guide part 12a on the side plate 12g.
The developing container lid 29 is fixed by ultrasonic welding while the peripheral edges are in contact with the end plates 12h and 12i.

As shown in FIG. 11, the end of the charging roller 8a is reduced in diameter and a journal 8a2 is provided around the center of rotation.
Is rotatably fitted with a spacer roller 8n. The spacer roller 8n is in pressure contact with the photosensitive drum 7 outside the image area by the elastic force of a compression coil spring (not shown).

With such a configuration, a gap is provided between the photosensitive drum 7 and the charging roller 8a, and the transfer residual toner that is going to pass through the opposing portion between the charging roller 8a and the photosensitive drum 7 is charged by the charging roller 8a. The direction of movement of the peripheral surface is opposite to the direction of movement of the peripheral surface of the photosensitive drum 7, and a charging bias is applied to capture the image.

In the above description, as shown in FIG. 2, the line connecting the swing center SC to the center of the charging roller 8a and the line connecting the charging roller 8a to the center of the photosensitive drum 7 are substantially perpendicular.

As shown in FIG. 2, the developing roller 10d is attached to the developing frame 12 so as to be swingable about the center of pressure. As shown in FIG.
The developing roller is attached to the reduced diameter journal portion 10d1 on both sides of
A spacer roller 10j having a radius larger by a development gap than 10d is fitted. A swing arm 32 fitted with the journal portion 10d1 is provided outside the spacer roller 10j.

FIG. 18 is a cross-sectional view perpendicular to the developing roller 10d showing the vicinity of the side surface of the swing arm 32. The root of a swing arm 32 is swingably supported by a support shaft 33 press-fitted in the longitudinal direction into both end plates 12h and 12i of the developing frame 12. A bearing hole 32a is provided almost directly above the swing arm 32 when viewed from the support shaft 33, and a stopper portion is provided above the bearing hole 32a.
32b is provided. The spring seat 32c is provided on a line substantially perpendicular to a line connecting the center of pressure of the support shaft 33 and the center of the bearing hole 32a.

In the bearing hole 32a of the swing arm 32, journal portions 10d1 at both ends of the developing roller 10d are rotatably supported. A spring seat 32c and an end plate 12h of the developing frame 12,
A compression coil spring 35 as a process urging means is contracted between the spring seat 12n provided on 12i. As a result, the developing roller 10d rotates around the pressing center SLv toward the photosensitive drum 7 and is pressed, and the spacer roller 10j presses against the end of the photosensitive drum 7 outside the image area, and the developing roller 10d is pressed. A predetermined gap (0.2
１．０1.0 mm) is maintained.

The stopper portion 32b contacts the developing roller cover 36 during disassembly, thereby preventing the swing arm 32 from turning outward in FIG. Therefore, in the assembled process cartridge B, the stopper 31b and the developing roller cover 36 do not abut.
The developing roller cover 36 extends between the swing arms 32 on both sides in the longitudinal direction, and is screwed to the developing frame 12.

(Removable Configuration of Process Cartridge to Image Forming Apparatus Main Body) As shown in FIGS. 3 and 7, flange-like guide portions 12a and 29b are provided on the left and right sides of the upper portion of the process cartridge B as viewed in the mounting and dismounting direction. The guide portions 12a and 29b are engaged with guides 14c of guide rails 14b provided on the cartridge mounting portion 14a, and are attached to and detached from the image forming apparatus main body 14.

Further, the process cartridge B is provided with contacts which are respectively connected to respective contacts on the apparatus main body side which are connected to a high-voltage power supply (not shown) provided on the apparatus main body 14 when the process cartridge B is mounted on the apparatus main body 14.

As shown in FIGS. 3 and 8, a drum ground contact 101 communicating with the photosensitive drum 7 is provided on the front side when viewed from the mounting direction of the process cartridge B. As shown in FIGS. 7, 9 and 10, on the back side when viewed from the mounting direction of the process cartridge B, a conductive brush contact 102 communicating with the conductive brush 11, a charging bias contact 103 communicating with the charging roller 8a, A developing bias contact 104 communicating with the developing roller 10d is provided.

A connector 105 with an IC is provided on the back side when viewed from the mounting direction of the same process cartridge B as the side on which the conductive brush contact 102, the charging bias contact 103 and the developing bias contact 104 are provided. When the cartridge B is mounted on the apparatus main body 14, the cartridge B is connected to a connector (not shown) on the apparatus main body side.
Write or read 5 to control.

On the end face on the far side when viewed from the mounting direction of the process cartridge B, there are provided three driving force receiving portions serving as shaft couplings which rotate about a longitudinal axis. When the process cartridge B is mounted on the apparatus main body, the three driving force receiving portions are connected to the driving members of the apparatus main body 14.

As shown in FIG. 7, the three end faces of the process cartridge B, which are shaft joints that rotate around the longitudinal axis, are located at positions away from the end faces as viewed in the mounting direction of the process cartridge B. A photoreceptor drum coupling 37, a charging unit coupling 38, and a developing unit coupling 39, which are driving force receiving units, are provided externally.

(Driving of Charging Roller) As shown in FIGS. 11, 20, and 21, the gear unit 24 fixed to the rear end portion of the charging unit C in the longitudinal direction is divided into two divided gear cases 6.
A gear train 24G is housed in 1, 62.

The gear cases 61 and 62 are divided in two in the longitudinal direction. The gear case 61 abuts on the rear end side of the charging frame 13 in the longitudinal direction, and the gear cases 61 and 62 are fixed to the charging frame 13 together with small screws 58. ing.

FIG. 19 is a front view of the charging unit C as viewed from the longitudinal direction at the rear end in the longitudinal direction. FIG. 20 is a cross-sectional view taken along ABCDE of FIG. Charger coupling
The two-stage gear 24a is provided integrally with 38. Two-stage gear
The center hole 24a3 is rotatably fitted to a support shaft 61a which is fixed to the gear case 61 with a small screw 63 and protrudes in the longitudinal direction. The support shaft 61a may be formed integrally with the gear case 61. The charging roller 8a is a member mounting portion 13f of the charging frame 13.
Is rotatably supported by a rear end charging roller bearing 20 fitted to the rear end.

The large gear 24a1 of the two-stage gear 24a meshes with a charging roller gear 24b fixed to one end of the charging roller 8a. The hole 62a of the gear case 62 has a magnet 8b.
Is supported at one end. Large gear 24a1 of two-stage gear 24a
And the small gear 24a2 are fitted and fixed. However, they may be integrally formed.

(Pressing Force Acting Between Charging Roller and Photosensitive Drum) FIG. 22 is a diagram showing a load relationship when a rotational force is transmitted from the charging unit coupling 38 to the charging unit C having the charging roller 8a.

Between the photosensitive drum 7 and the charging roller 8a, the charging roller 8a and the photosensitive drum 7 are charged, and the transfer residual toner on the photosensitive drum 7 after the transfer is transferred to the back side of the charging roller 8a. A gap for charging the magnetic brush is provided so that the charge can be adjusted and then sent out.

To provide this gap, a spacer roller 8n is rotatably fitted to the journal portion 8a2 of the charging roller 8a. The radius of the spacer roller 8n is larger than the radius of the charging roller 8a by the gap between the charging roller 8a and the photosensitive drum 7. The spacer rollers 8n are in pressure contact with the photosensitive drum 7 at both ends outside the charging area in the longitudinal direction of the photosensitive drum 7. Photoconductor drum 7 and charging roller 8
a rotates in the same direction, and the peripheral surfaces of the photosensitive drum 7 and the charging roller 8a move in opposite directions to each other in the charging area and both sides in the longitudinal direction.

Assuming that the center of the charging roller 8a is O3 and the center of the charging portion coupling 38 is O4, a line connecting the center O1 of the photosensitive drum 7 and the center O3 of the charging roller 8a and the center of the charging roller 8a are charged. The angle θ formed by a line connecting the center O4 of the partial coupling 38 to the center O4 is substantially a right angle.

As the angle θ approaches 180 degrees, the charging roller 8a is attached to the charging unit coupling 38 except for a range in which the charging roller 8a receives a force toward the photosensitive drum 7 by a wedge action.
It is sufficient that the torque T applied from the coupling of the fourteen drive units presses the charging roller 8a against the photosensitive drum 7. In FIG. 22, the center O3 of the charging roller 8a needs to be located on the left side of a line connecting the center O4 of the charging portion coupling 38 and the center O1 of the photosensitive drum 7.

The torque T received by the charging unit coupling 38 causes the cylindrical shaft portion 26 a supporting the charging unit C and the hole 23
The charging unit C tries to rotate counterclockwise around the center of a (see FIG. 11). Therefore, the charging roller 8
Assuming that the distance between the center O3 of a and the center O4 of the charging portion coupling 38 is J, a T / J pressing force is generated between the spacer roller 8n of the charging roller 8a and the photosensitive drum 7.

The pressure contact force generated by the torque T is such that the rear spacer roller 8n1 receiving the drive input of the spacer rollers 8n provided at both ends in the longitudinal direction of the charging roller 8a receives a larger pressure contact force as a ratio than the front spacer roller 8n2. .

On the other hand, as shown in FIG. 23, on the front side in the longitudinal direction, a compression coil spring 30a as a process urging means presses in the same direction as the rotation direction of the torque T above the charging portion coupling 38. It is contracted between the developing unit D and the charging unit C. The distance between the center line of the compression coil spring 30a and the center O4 of the charging portion coupling 38 is L1.
Assuming that the elastic force of the compression coil spring 30a is Fs1, a torque of Fs1 · L1 acts around the cylindrical shaft portion 26a and the hole 23a, and this torque causes a space between the spacer roller 8n1 of the charging roller 8a and the photosensitive drum 7 by this torque. Is Fs1 · L1 /
A pressing force of J occurs.

As shown in FIG. 24, a compression coil spring 30b as an urging means is provided on the far side in the longitudinal direction so as to apply pressure in a direction opposite to the rotation direction of the torque T below the charging portion coupling 38. When the distance between the center line of the compression coil 30b and the center O4 of the charging unit coupling 38 is L2, the compression is performed around the cylindrical shaft portion 26a and the hole 23a. The elastic force of the coil spring 30a is Fs2, and a torque of Fs2 · L2 acts. By this torque, a pressure reducing force of Fs2 / L2 / J is generated between the spacer roller 8n2 of the charging roller 8a and the photosensitive drum 7.

Since the charging unit C is configured as described above, the charging unit C receives the pressing force by the driving torque T and the pressing force by the compression coil spring 30a on the front side in the longitudinal direction. On the far side in the longitudinal direction, 10 to 15 N by the driving torque T
(1.0 to 1.5 kgf) while a compression coil spring 30b generates 5 to 10 N (0.5 to 1.0 kgf).
It receives the pressure reduction force of f). Thereby, the spacer roller 8n
1 and the spacer roller 8n2 are almost equivalent to 5 to 10N (0.
Under the pressure of 5 to 1.0 kgf), a necessary and sufficient pressure is generated between the charging roller 8a and the photosensitive drum 7 in a balanced manner at both ends in the longitudinal direction.

As a result, the pressing force against the spacer roller 8n2 on the back side in the longitudinal direction can be reduced, and the pressing force on the spacer roller 8n2 on the front side can be made substantially the same as that of the spacer roller 8n1 on the front side without receiving excessive pressing force. Can be prevented from being deformed or scraped, and the distance between the charging roller 8a and the photosensitive drum 7 can be reduced.

As described above, according to the first embodiment, the charging is performed between the drum frame as the first frame supporting the photosensitive drum 7 and the frame detachably mounted on the drum frame and supporting the charging roller 8a. By biasing the roller 8a with an elastic body that biases the photosensitive drum 7 in the opposite direction, the spacer roller 8n on the back side in the longitudinal direction can reduce the influence of excessive pressing force due to the rotational driving torque, It is possible to make the pressure contact force substantially equal to that of the front spacer roller 8n, and it is possible to prevent the spacer roller 8n from being deformed and scraped due to creep, and the gap between the charging roller 8a and the photosensitive drum 7 from being reduced. Therefore, the pressing force in the longitudinal direction between the photosensitive drum 7 and the charging roller 8a acting on the photosensitive drum 7 can be kept uniform, and the gap can be kept stable.

(Second Embodiment) A second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and a description thereof is partially omitted.

The developing roller 10d is attached to the developing frame 12 so as to be able to swing about a pressing center SLv. As shown in FIG. 17, spacer rollers 10j having a radius larger by a developing gap than the developing roller 10d are fitted into the reduced journal portions 10d1 on both sides of the developing roller 10d. Journal part outside spacer roller 10j
A swing arm 32 fitted with 10d1 is provided.

FIG. 25 is a cross-sectional view of the vicinity of the side surface of the swing arm 32, which is perpendicular to the developing roller 10d. The root of a swing arm 32 is swingably supported by a support shaft 33 press-fitted in the longitudinal direction into both end plates 12h and 12i of the developing frame 12. A bearing hole 32a is provided almost directly above the support shaft 33 of the swing arm 32, and a stopper 32b is provided for the information. A spring seat 37c is provided for cleaning substantially perpendicular to a line connecting the center of pressure SLv, which is the center of the support shaft 33, and the center of the bearing hole 32a.

When the rotational force is transmitted to the drive gear 15a (see FIG. 7) from the coupling of the drive unit of the image forming apparatus main body 14 to the developing unit coupling 39 on the rear side in the longitudinal direction, the developing roller 10d is moved to the state shown in FIG. 7, the developing unit coupling 39 arranged coaxially with the driving gear 15a rotates clockwise, and the developing roller coupling 15b moves from the driving gear 15a (see FIG. 7).
The rotation is transmitted to. In FIG. 25, the developing roller gear
The developing roller 10d arranged coaxially with 15b rotates counterclockwise. Due to the meshing force of the gear at this time, the developing roller 10d exerts a large urging force on the photosensitive drum 7 via the spacer roller 10j on the rear side in the longitudinal direction.

On the other hand, between the spring seat 37c of the swing arm 32 and the spring seat 12p provided on the end plates 12h and 12i of the developing frame 12, a coil spring 70 as urging means is provided. As a result, an urging force is exerted on the developing roller 10d to swing around the pressing center SLv in the direction opposite to the direction of the photosensitive drum 7.

Thus, the spacer roller on the back side in the longitudinal direction is formed.
10j is the end of the photosensitive drum 7 outside the image area,
The urging force due to the gear meshing force due to the rotation drive transmission,
The pressure reduction force by the coil spring 70 acts, so that the spacer roller 10j on the far side in the longitudinal direction has a smaller pressure contact force, and can have substantially the same pressure contact force as the spacer roller 10j on the front side in the longitudinal direction. The spacer roller 10j is deformed and scraped by creep. It is possible to prevent the gap from becoming too small.

As described above, according to the second embodiment, also in the developing means, the developing roller 10d is urged by the elastic member which urges the photosensitive drum 7 in the opposite direction to the photosensitive drum 7, so that the developing roller 10d is positioned on the rear side in the longitudinal direction. Spacer roller 10j can reduce the influence of excessive pressing force due to rotational driving torque,
The pressure contact force can be made substantially equal to that of the front spacer roller 10j, and it is possible to prevent the spacer roller 10j from being deformed and scraped due to creep, and the gap between the developing roller 10d and the photosensitive drum 7 from being reduced. . Therefore, the pressing force between the photosensitive drum 7 and the developing means acting on the photosensitive drum 7 in the longitudinal direction can be uniformly maintained, so that the gap can be stably maintained.

(Other Embodiments) In the above-described embodiment, the charging means and the developing means are illustrated as the processing means acting on the photosensitive drum 7, but the invention is not limited thereto. It can also be used.

In the above-described embodiment, a four-color laser color printer has been described as an example of an image forming apparatus. However, the present invention is not limited to this. Is also good.

In the above-described embodiment, the developing frame 12 having the developing roller 10d and the drum frame having the photosensitive drum 7 are provided separately. However, the present invention is not limited to this. An image forming frame supporting the roller 10d, a developing roller supporting member rotatably supporting the developing roller 10d and swingably supported by the image forming frame; It may be configured to include a developing roller urging unit that urges in the direction of the carrier.

[0089]

As described above, according to the present invention, the image forming apparatus can be attached to and detached from the image forming apparatus having the first frame supporting the image carrier and the second frame supporting the processing means acting on the image carrier. Process cartridges
An urging means for urging the process means in a direction away from the image carrier between the first frame and the second frame, so as to equalize a pressing force between the image carrier and the process means; , The gap between the image carrier and the process means can be stably maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus.

FIG. 2 is a sectional view of a process cartridge.

FIG. 3 is a front view of the process cartridge.

FIG. 4 is a right side view of the process cartridge.

FIG. 5 is a left side view of the process cartridge.

FIG. 6 is a plan view of the process cartridge.

FIG. 7 is a rear view of the process cartridge.

FIG. 8 is a perspective view of the process cartridge viewed from the front right side.

FIG. 9 is a perspective view of the process cartridge as viewed from a later manner.

FIG. 10 is a perspective view of the process cartridge turned upside down and viewed obliquely from behind.

FIG. 11 is a front view of the charging unit.

FIG. 12 is a front view when the blade is removed from the charging unit.

FIG. 13 is a rear view of the developing unit viewed with a rear cover removed.

FIG. 14 is a front view of the developing unit viewed with a front cover removed.

FIG. 15 is a perspective view showing the inside of the rear cover.

FIG. 16 is a perspective view of the inner side of the front cover.

FIG. 17 is a side view of the developing unit.

FIG. 18 is a front view showing a supporting portion of the developing roller.

FIG. 19 is a front view showing a longitudinal rear end portion of the charging unit.

FIG. 20 is a sectional view of a process cartridge.

FIG. 21 is a perspective view of a charging unit.

FIG. 22 is a rear view showing a driving relationship of the charging roller.

FIG. 23 is a front view showing a process urging unit of the charging unit.

FIG. 24 is a rear view showing the urging means of the charging unit.

FIG. 25 is a rear view showing the urging means of the developing roller.

[Explanation of symbols]

B: Process cartridge (BY, BM, BC, B
B) C: charging unit D: developing unit O1: center O3: center O4: center SC: swing center SLv: pressing center TO: toner supply container (TOY, TOM, TOC, T)
OB) 1 Optical scanning system (1Y, 1M, 1C, 1Bk) 2 Recording medium 3 Feeding means 3a Feeding cassette 3b Pickup roller 3c Retard roller pair 3d Transport roller 3f Transport roller 3g Resist Roller pair 3h discharge roller pair 3i discharge roller pair 4 transfer roller (4Y, 4M, 4C, 4Bk) 4a transfer belt 4b drive roller 4c driven roller 4d secondary transfer facing roller 5 fixing means 6 Tray (6Y, 6M, 6C, 6Bk) 7 ... Photoconductor drum (7Y, 7M, 7C, 7Bk) 8 ... Magnetic brush charger 8a ... Charging roller 8a1 ... Seal part 8a2 ... Journal part 8b ... Magnet 8c ... Regulator blade 8d ... Support metal plate 8j ... Machine screw 8n ... Spacer roller 8n1 ... Spacer roller 8n2 ... Spacer roller 10 ... developing means 10a ... developing container 10c ... magnet 10d ... developing roller 10d1 ... journal part 10e ... regulating blade 10f ... partition wall 10g ... stirring screw 10h ... stirring screw 10j ... spacer roller 11 ... conductive brush 12 ... developing frame 12a ... guide part 12e. ... Seat part 12f ... Lower part 12g ... Side part 12h ... End plate part 12i ... End plate part 12j ... Hole 12m ... Hole 12n ... Spring seat 12p ... Spring seat 13 ... Charging frame 13a ... Bottom edge 13b ... Top and bottom wall 13c ... Square part 13d: Top plate section 13e: Member mounting section 13f: Member mounting section 13g: Seat section 13h: Female thread 13i: Dowel 14: Device body 14a: Cartridge mounting section 14b: Guide rail 14c: Guide 15: Secondary transfer roller 15a: Drive gear 15b Developing roller gear 16 Front cover 17 Rear cover 17a Hollow cylindrical shaft support 20 Rear charging roller bearing 21b Sealing material 21g Roller material 22 ... Charge roller bearing 23 ... End cover 23a ... Hole 24 ... Gear unit 24G ... Gear train 24a ... Two-stage gear 24a1 ... Large gear 24a2 ... Small gear 24a3 ... Center hole 24b ... Charge roller gear 25 ... Back member 26 ... Gear case 26a ... Cylindrical shaft part 29 ... Development container lid 29b ... Guide part 30a ... Compression coil spring 30b ... Compression coil spring 31 ... Image forming part (31Y, 31M, 31C, 31Bk) 31b ... Stopper 32 ... Swing arm 32a … Bearing hole 32b… Stopper part 32c… Spring seat 33… Support shaft 35… Compression coil spring 36… Developing roller cover 37… Photoconductor drum coupling 37c… Spring seat 38… Charging part coupling 39… Developing part coupling 40… Intermediate transfer means 58 ... small screw 61 ... gear case 61a ... support shaft 62 ... gear case 62a ... hole 63 ... small screw 70 ... compression coil spring 101 ... drum earth contact 102 ... conductive brush contact 103: charging bias contact 104: developing bias contact 105: connector with IC

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H071 BA05 BA13 BA15 BA16 BA29 DA06 DA08 DA15 2H077 AD06 AD36 BA07 BA08 BA09 EA03 GA04 2H200 FA12 GA12 GA16 GA18 GA23 GA34 GA47 GA57 GB13 HA02 HB12 HB17 HB22 JC03 JC15 MA02 MA03 MA20

Claims (11)

[Claims] 1. A process cartridge detachable from an image forming apparatus, comprising: a first frame supporting an image carrier; and a second frame supporting process means acting on the image carrier. A process cartridge, comprising: an urging means for urging the process means in a direction away from the image carrier between the second frame and the second frame. 2. The process cartridge according to claim 1, wherein the second frame is swingably supported with respect to the first frame. 3. The process cartridge according to claim 1, wherein the process unit is urged between the first frame and the second frame with respect to the image carrier. A process cartridge comprising means. 4. The process cartridge according to claim 1, wherein said process means is a charging means for charging said image bearing member. 5. The process cartridge according to claim 4, wherein said charging means has a magnetic brush charger using a magnetic carrier. 6. The process cartridge according to claim 1, wherein the process unit is a developing unit that develops the image carrier with a developer. cartridge. 7. The process cartridge according to claim 6, wherein said developing means has a developing roller, and said urging means is provided at one end of a driving means for driving said developing roller in a longitudinal direction of said developing roller. A process cartridge to be provided. 8. The process cartridge according to claim 7, wherein said process urging means is provided at one end side of said developing roller which has no driving means for driving said developing roller in a longitudinal direction of said developing roller. cartridge. 9. A process cartridge detachable from an image forming apparatus having an image forming frame for supporting an image carrier and a developing roller for developing the image carrier with a developer, wherein the developing roller is rotatable. A developing roller supporting member that is pivotally supported by the image forming frame and is supported so as to be swingable on the image forming frame. A process cartridge, further comprising an urging means for urging in a direction away from the image carrier. 10. The process cartridge according to claim 9, wherein said developing roller is urged against said image bearing member at one end side of said developing roller which has no driving means for driving said developing roller in a longitudinal direction of said developing roller. A process cartridge provided with roller biasing means. 11. An image forming apparatus in which a process cartridge for forming an image to be transferred to a recording medium is detachably configured, wherein the process cartridge is configured to be detachable.
An image forming apparatus comprising the process cartridge according to any one of the above.