JP2002072647A - Developing means, process cartridge and electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a detection error of a developer concentration detecting means by stabilizing developer concentration by limiting replenishing position of toner inside a developing container. SOLUTION: In the device, a guide member (29b) is provided in a lower part of a toner replenishing opening of a developing container (10a) and replenishing is carried out only to one row 10g between two rows of agitating screws 10g and 10h. The toner replenishing position is positioned on a downstream side of the carrying direction against the developer concentration detecting means 150.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a developing means, a process cartridge having the same, and an electrophotographic image forming apparatus having the process cartridge detachably provided.

Here, an electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming method, and includes, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.). ) Facsimile machine, word processor, etc.

A process cartridge generally comprises a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum integrally formed as a cartridge, and this cartridge is detachably mountable to an image forming apparatus main body. Or at least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive drum are integrally formed into a cartridge so that the cartridge can be attached to and detached from an image forming apparatus main body. Are integrated into a cartridge so as to be detachable from the apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is mounted on the main body of the image forming apparatus. A process cartridge system which can be attached to and detached from is used. 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.

[0005]

SUMMARY OF THE INVENTION The present invention is a further development of the above-mentioned prior art, in which a developing means capable of stabilizing a developer concentration by limiting a developer replenishing position in a developing container, It is an object to provide a process cartridge and an electrophotographic image forming apparatus.

[0006]

The main aspects of the present invention are as follows, if they are indicated by the numbers corresponding to the claims.

According to a first aspect of the present invention, there is provided a developing container to which a developer is supplied, a plurality of stirring and conveying members for stirring and conveying the developer in the developing container, and a developer in the developing container. And a developer carrying member for holding a predetermined amount of the developer carrying member, wherein any of the stirring and carrying members of the plurality of stirring and carrying members except for the one disposed at a position closest to the developer carrying member. And a guide member for replenishing the developer.

This guide member is preferably provided below a supply port provided above the developing means.

A second invention according to the present application is characterized in that the guide member is integrated with a developing container lid.

According to a third aspect of the present invention, in the developing means, a first stirring / transporting member provided at a position close to the developer carrier, and a first stirring / transporting member provided at a position remote from the developer carrier. Wherein the guide member replenishes the developer to the second stirring and conveying member.

According to a fourth aspect of the present invention, a developer concentration detecting means is provided on a conveying path of a stirring member to which a developer carrier is supplied, and a developer conveying direction viewed from the developer concentration detecting means. A developer replenishing position by the guide member is arranged on the downstream side of the developing device.

According to a fifth aspect of the invention, there is provided at least an image carrier, and at least one of the first to fourth developing means arranged around the image carrier. Features.

According to a sixth aspect of the present invention, there is provided an image forming apparatus main body and a process cartridge according to claim 5 which is detachably mountable to the image forming apparatus main body. It is characterized in that the formed developer image is transferred to a recording medium to form an image.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention;

In the following description, the longitudinal direction refers to a direction crossing the recording medium transport direction and parallel to the recording medium. The left and right are the left and right as viewed in the transport direction of the recording medium. Further, "above the process cartridge" means above the process cartridge in the mounted state.

FIG. 1 is a drawing showing an image forming apparatus to which the present invention is applied.

The image forming apparatus includes image forming units 31Y and 31Y for forming a toner image on a photosensitive drum as an image carrier.
1M, 31C, 31Bk, a transfer belt 4a for temporarily transferring the toner image, and a secondary transfer roller 4 serving as a transfer unit for transferring the toner image on the belt 4a to the recording medium 2.
0, the recording medium 2 is transferred to the transfer belt 4a and the secondary transfer roller 40
A feeding unit, a fixing unit, and a discharging unit that convey the recording medium 2 to a feeding unit that transfers the recording medium 2 to the transfer unit are provided.

Hereinafter, the image formation will be described.

As shown in FIG. 1, a plurality of recording media (for example, recording paper, OHP sheet, cloth, etc.)
Is mounted detachably. Feeding cassette 3 by pickup roller 3b
The recording medium 2 fed from a is separated one by one by a pair of retard rollers 3c, and is conveyed to a pair of registration rollers 3g by conveyance rollers 3d and 3f.

When the recording medium 2 is conveyed, the registration roller pair 3g stops rotating, and the recording medium 2 is skewed by being hit against the nip.

Process cartridge B including image carrier
In the case of the four-drum full-color system, four colors of yellow, magenta, cyan, and black are arranged in parallel in Y, BM, BC, and BB as shown in the figure. An optical scanning system 1Y, 1M, 1C, 1Bk is provided for each of the process cartridges BY, BM, BC, BB, and the photosensitive drums 7 (7Y, 7M, 7C, 7C,
7Bk), after the toner image is formed on the transfer roller 4
(4Y, 4M, 4C, 4Bk), the respective color toners 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 40 at a predetermined timing, and is transferred to the transfer belt 4a.
After the upper toner image is transferred onto the recording medium 2 and fixed by the fixing device 5, the toner image is discharged by discharge roller pairs 3h and 3i.
It is loaded on the tray 6 on the apparatus body 14.

The image forming units 31Y, 31M, 31C,
31Bk is a process cartridge BY, BM, BC, BB except for the optical scanning systems 1Y, 1M, 1C, 1Bk.
And toner supply containers TY, TM, TC, and TB. Since the configuration of the process cartridge is the same, the process cartridge BY will be described.

As shown in FIG.
Y is a device in which a charging unit, an exposure unit, a developing device 10 as a developing unit, and a transfer opening are provided around the photosensitive drum 7. In this embodiment, a two-component developer having a magnetic carrier powder is used. Therefore, as the photosensitive drum 7 used in the embodiment of the present invention, a commonly used organic photosensitive member or the like can be used, and preferably, the resistance of the organic photosensitive member is 10 ² to 10 ¹⁴ Ω. When a material having a surface layer having a material of cm or an amorphous silicon photoreceptor is used, charge injection charging can be realized, which is effective in preventing ozone generation and reducing power consumption. Further, the chargeability can be improved.

Therefore, in the present embodiment, a photosensitive drum 7 having a negatively charged organic photosensitive member provided on an aluminum drum base is used.

The charging means is a magnetic brush charger 8 using a magnetic carrier. The charger 8 has a fixed magnet 8b disposed inside 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.

In the present embodiment, the developing device 10 employs a method of developing a two-component developer in a contact state (two-component non-contact development).

FIG. 2 shows a developing device 10 for two-component magnetic brush development used in the present embodiment.

The developing device 10 includes a developing container 10a to which the developer is supplied, a plurality of stirring screws 10g and 10h as a plurality of stirring and conveying members for stirring and conveying the developer in the developing container 10a, and a developing container 10a. Sleeve 10d as a developer carrier for holding a predetermined amount of the developer therein
And a guide member 29b for replenishing the developer with respect to the stirring screw 10g except the one disposed at the position closest to the developing sleeve 10d.

As described above, by supplying the developer to the stirring / transporting member located at a position farther from the developer carrying member except for the stirring / transporting member located near the developer carrying member in the developing container, the developer is provided. Is sufficiently stirred to supply a developer having a constant concentration to the developer carrying member.

Further, by supplying the developer to the downstream of the stirring / conveying member in the conveying direction with respect to the developer concentration detecting means, erroneous detection by the developer concentration detecting means is prevented and the developer concentration is stabilized. In addition, it is possible to prevent the toner from scattering in the developing container.

In this embodiment, a stirring screw 10h as a first stirring and conveying member is located at a position near the developing sleeve 10d, and a stirring screw 10g as a second stirring and conveying member is located at a position far from the developing sleeve 10d. Are provided, and a guide member 2 is attached to a stirring screw 10g as a second stirring and conveying member far from the developing sleeve 10d.
9b replenishes the developer.

The guide member 29b is provided below the replenishing port 29c (see FIG. 24) provided in the upper part of the developing means, and is formed integrally with the lid 29 of the developing container.

Further, a developer concentration detecting means 150 is provided in a conveying path of the stirring screw 10g to which the developer is supplied, and a guide member 29b is provided downstream from the developer concentration detecting means 150 in the developer conveying direction. Is located.

The developing sleeve 10d has a hollow cylindrical shape and is rotatably supported. A fixed magnet 10c is provided in the developing sleeve 10d. The developing sleeve 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 photoconductor drum 7 and the developing sleeve 10d are not in contact with each other and have a gap of about 0.2 to 1.0 mm, and are set so that the developer can be developed while being in contact with the photoconductor drum 7. .

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. The toner supplied from the toner supply container TY has a stirring screw of 10 g.
When viewed from the developer concentration detecting means 150, the stirring screw 10b drops to the downstream side and is agitated while being sent in one longitudinal direction (arrow in the figure) and passes through the portion without the partition wall 10f at the other end. Then, the liquid is moved to one end side, and then passes through a portion without the partition wall 10f on one end side, is stirred while being sent by the stirring screw 10g, and circulates (see FIG. 23).

The mixture ratio of the toner and the carrier circulating while being stirred is detected by the developer concentration detecting means 150.
The mixture ratio of the carrier and the toner is always detected, and the toner is supplied from the toner supply container TY in accordance with the consumption of the toner so that the mixture ratio becomes constant. Developer concentration detecting means 150
Is disposed near the stirring screw 10g in the developing container 10a (see FIG. 2).

Here, the developing step of visualizing the electrostatic latent image formed on the photosensitive drum 7 by the two-component magnetic brush method using the developing device 10 and the collision system of the developer will be described.

First, in the process of being transported, the developer pumped up by the poles of the magnet 10c with the rotation of the developing sleeve 10d is regulated by the regulating blade 10e arranged perpendicular to the developing sleeve 10d, ie, by the developing blade. It is regulated and a thin layer is formed on the developing sleeve 10d. Here, when the thin layer-formed developer is conveyed to the developing main pole, ears are formed by magnetic force. The electrostatic latent image on the photosensitive drum 7 is developed with the developer formed in the spike shape, and thereafter, the developing sleeve 1 is developed by the repulsive magnetic field.
The developer on 0d is returned into the developing container 10a.

A DC voltage and an AC voltage are applied to the developing sleeve 10d from a power source (not shown). Generally, in the two-component developing method, when an AC voltage is applied, the developing efficiency increases,
Although the image has high quality, fogging tends to occur easily. For this reason, usually, the developing sleeve 1
By providing a potential difference between the DC voltage applied to 0d 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 device 4. The intermediate transfer device 4 drives the endless transfer belt 4a with a driving roller 4b and a 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 4Y, 4M, 4C, and 4Bk are provided in the transfer belt 4a.
Power is supplied from a high-voltage power supply while generating a pressing force from the inside of the belt 4a toward the photoconductor drum 7, so that the toner on the photoconductor drum 7 is charged from the back side of the transfer belt 4a with the opposite polarity to the toner. The images are sequentially transferred onto the upper surface 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 conductive brush 11 is brought into contact with the photosensitive drum 7 between the intermediate transfer device 4 and the magnetic brush charger 8, and a bias having a polarity opposite to the charging bias is applied. The transfer residual toner of the positive polarity passes through the magnetic brush charger 8, and the transfer residual toner of the negative polarity is temporarily captured by the conductive brush 11, and is discharged 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 (BY, BM, BC,
BB) is a developing unit D in which the electrophotographic photosensitive drum 7 and the developing device 10 are integrally formed by a developing frame 12, and a charging roller 8a, a regulating blade 8c, a charging brush 11 and the like are integrally formed by a charging frame 13. The charging unit C is assembled for each unit. Further, the developing unit D and the charging unit C are positioned and connected by a front cover 16 and a rear cover 17 (see FIG. 4) from both ends in the longitudinal direction.

FIGS. 3 to 7 show the process cartridge B.
It is a projection view of (BY, BM, BC, BB). 3 is a front view, FIG. 4 is a right side view, FIG. 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.
9 is a perspective view seen from the front diagonal, FIG. 9 is a perspective view seen from the rear oblique, and FIG. 10 is a perspective view seen from the rear oblique with the bottom view side 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. As shown in FIG. 2, FIG. 4, FIG. 8, FIG.
Constitutes a part of the exterior of the process cartridge B. The lower edge 13a of the charging frame 13 is parallel to the photoconductor drum 7 in the longitudinal direction at a distance close to the photoconductor drum 7 as shown in FIGS. The lower edge 13a has substantially vertical upper and lower walls 13b so as to form the exterior of the process cartridge B.
3c is provided. The top plate 13d has a top plate 13d in a direction substantially horizontal from the corner 13c, and has a substantially key-shaped cross section.
Is a space, and a member mounting portion 1 is provided at both ends in the longitudinal direction.
3e and 13f are integrally formed.

FIG. 11 is a side view of the charging unit C viewed from the inside.

A charging roller bearing 22 and an end cover 23 are screwed together at one end on the front side of the charging frame 13 in the mounting direction of the process cartridge B (mounted in the longitudinal direction from the front of the apparatus body 14). Have been. 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. The seat 13g for mounting the blade with the side surfaces of the member mounting portions 13e and 13f raised in steps is a regulating blade 8c.
A female screw 13h and a dowel 13i are provided on a plane at both ends in contact with each other. A sealing material 21g, such as a sponge, is attached in the longitudinal direction to the flat surface retreated from the seat 13g. Further, the sealing portions 8 at both ends of the charging roller 8a are provided.
In order to prevent the developer from leaking outward in the axial direction along the circumferential direction of a1, a sealing material 21b such as felt is attached. Therefore, the 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 is fitted into the dowel 13i of the seat 13g of the charging frame 13 and screwed into the female screw 13b of the seat 13g by inserting a small screw 8k into a hole of the support metal 8d. While the seat 13g abuts, the sealing material 21a is compressed by the supporting metal plate 8d. Also, the seat 1 of the sealing material 21b is formed by the supporting metal plate 8d.
Nearly 3 g is compressed. 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 21.

As shown in FIG. 2, the developing frame 12 accommodates the stirring screws 10g and 10h on both sides of the partition wall 10f, and has a lower portion 12f having a seat 12e for mounting a regulating blade 10e, and a process cartridge B. Side 1 that forms the left exterior part when viewed from the mounting direction
2g, and at both ends in the longitudinal direction, FIG. 11, FIG. 13, FIG.
As shown in FIG. 7, the end plate 12h (rear side) and 12i (front side) are provided.

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. A hole 12m having the same diameter as the hole 23a of the charging frame 13 is provided in the other end plate portion 12i.

Therefore, the end plate 12h of the developing frame 12
With the cylindrical shaft portion 26a of the charging unit C inserted into the hole 12j, the cylindrical fitting hole 23 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 13, a hollow cylindrical shaft protruding in the longitudinal direction on the inner side of the rear cover 17. 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 portion 26a of the charging unit C.

A support shaft 27 which fits and protrudes into the hole 12m provided in the end plate portion 12i of the developing frame 12 (FIG. 1)
1, see FIG. 14), and fits into the hole 23a of the charging unit C. As a result, 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 rotatably supported by the developing frame 12.

As shown in FIG. 2, FIG. 6, and FIG. 8, in the upper part of the developing frame 12, the inner periphery of the guide part 12a above the side plate 12g and the peripheral edges abut the end plate parts 12h and 12i, and the developing container is ultrasonically welded. The lid 29 is fixed.

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 pressed against the image area of the photosensitive drum 7 by the spring force of the compression coil spring 30. 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.
The direction of movement of the peripheral surface a 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 sleeve 10d is attached to the developing frame 12 so as to be able to swing around the SLV pressing center. As shown in FIG. 17, the reduced diameter journal portions 10 on both sides of the developing sleeve 10d are used.
A spacer roller 10j having a radius larger by a developing gap than the developing sleeve 10d is fitted into d1. 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 sleeve 10d showing the vicinity of the side surface of the swing arm 32.

Both end plates 12h, 12 of the developing frame 12
The root of a swing arm 32 is swingably supported by a support shaft 33 press-fitted in the longitudinal direction with respect to i. A bearing hole 32 is located almost directly above the swing arm 32 when viewed from the support shaft 33.
a, and a stopper 32b is provided above it. 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 sleeve 10d are rotatably supported. Spring seat 32c and developing frame 12
A compression coil spring 35 is contracted between the end plate portions 12h and 12i and the spring seat 12n. As a result, the developing sleeve 10d is turned around the pressing center SLv toward the photosensitive drum 7 and is pressed, so that the spacer roller 1d is pressed.
0j is pressed against the end of the photosensitive drum 7 outside the image area,
A predetermined gap (0.2 to 1.0 mm) is maintained between the developing sleeve 10d and the photosensitive drum 7.

The stopper portion 32b contacts the developing sleeve cover 36 during assembly and disassembly, thereby preventing the swing arm 31 from turning outward in FIG. Therefore, in the assembled process cartridge B, the stopper 31b and the developing sleeve cover 36 do not abut. The developing sleeve 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 when viewed from the mounting direction. The guide portions 12 a and 29 b are provided in the cartridge mounting portion 14.
a and engages with a guide 14c of a guide rail 14b provided on the image forming apparatus main body 14 (see FIG. 22).

Further, the process cartridge B is provided with contacts which are respectively connected to respective contacts on the apparatus main body side which communicate with 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, the conductive brush 1 is located on the back side when viewed from the mounting direction of the process cartridge B.
1, a conductive brush contact 102 leading to the charging roller 8a, and a developing bias contact 104 leading to the developing sleeve 10d are provided.

As shown in FIG. 7, the three end faces of the process cartridge B, which are shaft joints that rotate about the longitudinal axis, are located at positions away from the end faces as viewed in the mounting direction of the process cartridge B. A drum coupling convex portion 37d, a charging portion coupling 38, and a developing portion coupling 39, which are driving force receiving portions, are provided to be viewed outside.

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. 19, one end of a drum ground contact 101 attached to the end plate 12i of the developing frame 12 is in elastic contact with the drum shaft 42. The drum ground contact 101 is provided on the developing frame 12, and the other end thereof is exposed to an external surface of the process cartridge B and serves as an external contact.

For assembly, the pin 43 can pass through the groove 12c provided in the radial direction from the drum shaft support hole 12b of the end plate portion 12i in the axial direction.

The driving-side drum flange 37 is connected to the drum cylinder 7a.
The flange 37b, which is in contact with the end of the drum cylinder 7a, and the journal 37 whose diameter is reduced from the flange 37b.
c, these are arranged in the axial direction in the order of the coupling convex portion 37d which is convex in the axial direction from the center of the end face of the journal portion 37c. The driving-side drum flange 37 is a molded plastic body.

The journal 37c is rotatably fitted via a collar 56 to a shaft support 17a provided integrally with the rear cover 17 which fits into the hole 12d of the end slope 12h of the developing frame 12.

The drum coupling convex portion 37d is provided as shown in FIG.
As shown in the figure, the triangular prism twisted around the drum shaft 42. The circumscribed circle diameter of this triangular prism is
The diameter is smaller than c.

As shown in FIG. 19, the driving device provided on the apparatus main body 14 is rotatably engaged with a fixed motor 45, a pinion 46 fixed to the motor shaft of the motor 45, and the pinion 46 and the large gear 48. Gear 47 supported by
A large gear 48, a large gear shaft 49 fixed to the large gear 48 and having a centering portion 57 rigidly connected to an end thereof, and a large gear shaft 4
9 and a coupling concave shaft 52. However, the intermediate gear 47 may be a two-stage gear having a plurality of stages.

The bearing 51 supports the large gear shaft 49 so as not to move in the axial direction. The coupling concave portion 52a has a hole serving as a twisted regular triangular prism, and the coupling convex portion 37
d is axially disengaged. When the coupling convex portion 37d and the coupling concave portion 52a are fitted, the coupling convex portion 3d
The ridge of the twisted regular triangular prism of 7d is the coupling recess 52.
By contacting the surface of the twisted triangular prism a, the coupling convex portion 37d and the coupling concave portion 52a are aligned, and their rotation centers coincide with each other. The centering portion 57 and the coupling concave portion 52 are provided with circumferential play that can be moved to a small extent. In the above description, the position of the coupling concave shaft 52 is determined at the position most moved to the process cartridge B side, and the coupling concave shaft 52 is supported so as to be able to retreat against the spring force (detailed description is omitted).

The support portion on the non-drive side of the drum shaft 42 is configured so that the drum shaft 42 does not move to the side opposite to the drive portion.
As shown in the drawing, a shaft retaining ring 53 is fitted into the drum shaft 42. The bearing 55 accommodated in the bearing case 54 fixed to the front cover 16 fixed to the end plate portion 12i of the developing frame 12 is inserted into the drum shaft 42 and the shaft retaining ring 53 and the bearing case 54 are moved in the axial direction. The movement of the drum shaft 42 toward the non-drive side is stopped by contacting the inner and outer wheel end faces on the opposite side. On the other hand, the movement of the photosensitive drum 7 to the drive side is restricted via the collar 56 in which the drum flange 37 fits into the journal portion 37c. In the above configuration, the distance between the shaft support 17a and the bearing 55 is set so that the photosensitive drum 7 is allowed to move in the axial direction with limited movement.
6 are larger than the distance between the surfaces facing the shaft support portion 17a and the bearing 55, respectively.

Since the driving device is configured as described above,
When the process cartridge B is mounted on the image forming apparatus main body 14, the positions of the cartridge frames (the developing frame 12, the front cover 16, and the rear cover 17) in the longitudinal direction with respect to the apparatus main body 14 are determined. Then, the tip end portion 42a of the drum shaft 42 is fitted into the center hole 57a of the centering portion 57, and the coupling convex portion 37d is fitted into the coupling concave portion 52a.
Fits. When the motor 45 rotates, the pinion 46, the intermediate gear 47, and the large gear 48 rotate to rotate the large gear shaft 4
From 9, the coupling concave shaft 52 rotates via the centering portion 57. Due to this rotation, the coupling convex portion 37d and the coupling concave portion 52a are twisted with each other, and the triangular prism is easily screwed in. The drum flange 37 and the coupling concave shaft 52 are attracted to each other, so that the tip of the coupling convex portion 37d becomes the bottom surface of the coupling concave portion 52a. Touch Thus, the axial position of the photosensitive drum 7 is determined to be constant with respect to the coupling concave shaft 52 positioned.

In the above, even if the process cartridge B is mounted on the apparatus main body 14, the coupling protrusion 3
When 7d and the coupling recess 52a do not fit,
The end face of the coupling convex portion 37d is the coupling concave shaft 52.
Push the edge of the mouth of the concave portion 52a of the
Is retracted against the spring force urging toward the process cartridge B. Therefore, after the process cartridge B is mounted, the fitting is instantaneous when the phases of the coupling convex portion 37d and the concave portion 52a match during pre-rotation. In the above description, the end face of the coupling convex portion 37d does not abut on the bottom of the coupling concave portion 52a, and the flange 37b of the drum flange 37 is directed toward the shaft support portion 17a of the rear cover 17 via a collar (not shown). In the embodiment described above, the developing unit and the charging unit capable of collecting the toner can be brought together by using the photosensitive drum as an integral cartridge. The supporting structure and the structure for engaging and disengaging the driving force receiving portion of the photosensitive drum and the driving member of the image forming apparatus main body are applicable to process cartridges in general.

Here, the process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed into a cartridge, and this cartridge is made detachable from the main body of the image forming apparatus. In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive drum are physically formed into a cartridge so as to be detachably mountable to the image forming apparatus main body. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrally formed into a cartridge so as to be detachable from the image forming apparatus main body.

(Driving of Developing Sleeve) Developing Sleeve 10
As shown in FIG. 17, a developing sleeve gear 15b is fixed to d at a position outside the journal portion 10d1 in the longitudinal direction. The developing sleeve gear 15b is shown in FIGS.
3. As shown in FIG. 21, it is engaged with the developing unit drive gear 15a. The developing unit drive gear 15a is formed integrally with the developing unit coupling 39, which is a rotational driving force receiving member of the developing unit, and has a cylindrical hole at the center of the rear side of the developing unit coupling 39. The cylindrical hole of the developing unit coupling 39 with the developing butterbur drive gear 15a is rotatably fitted to a shaft (not shown) provided in the end plate portion 12b of the developing frame 12 in the longitudinal direction.

The developing unit drive gear 15a has a two-stage gear 15c.
Are engaged with each other. The two-stage gear 15c is rotatably fitted to a shaft portion 12p provided integrally with the end plate portion 12h in the longitudinal direction. Large gear 15c of two-stage gear 15c
2 meshes with the stirring gear 15d connected to the rear shaft end of the stirring screw 10g shown in FIG. Stirring gear 15d
Meshes with a stirring gear 15e connected to the rear shaft end of the stirring screw 10b. The stirring gears 15d and 15e have a journal (not shown) at the middle in the axial direction, and have integrally connected unillustrated joints with the stirring screws 10g and 10b at the axial ends, respectively. The journal is rotatably supported by a bearing hole (not shown), and the connecting portion is provided with stirring screws 10h and 10h.
g and is supported so as to drive the stirring screws 10g and 10h by engaging with the rear end.

The front shaft ends of the stirring screws 10g and 10h have a center hole, and as shown in FIG. 14, the end plate portion 12i of the developing frame 12 at the end opposite to the above-mentioned end plate portion 12h in the longitudinal direction. The center holes of the shaft ends are rotatably fitted and supported on support shafts 19g and 19h, which are press-fitted into the longitudinal holes and whose tips project into the developing frame 12.

When the driving force is transmitted from the apparatus main body 14 while the process cartridge B is mounted on the apparatus main body 14, the developing unit coupling 39 rotates. The developing unit drive gear 15a integrated with the developing unit coupling 39 rotates the developing sleeve gear 15b, and the developing sleeve 10d rotates. The developing unit driving gear 15a is a two-stage gear 15c.
The stirring gear 15d is driven via the, and the rotation of the stirring gear 15d is transmitted to the stirring gear 15e. Then stirring screw 1
0 g and 10 h rotate, and agitate while circulating the toner.

The developing sleeve 10d is connected to the photosensitive drum 7
It rotates in the same direction as. Therefore, in the facing portion (developing area) of the peripheral surface of the developing sleeve 10d and the peripheral surface of the photosensitive drum 7, these peripheral surfaces move in opposite directions. Therefore, spacer rollers 10j (see FIG. 17) rotatably provided at both ends of the developing sleeve 10d roll with the photosensitive drum 7 and rotate in the opposite direction to the developing sleeve 10d.

Each of the gears 15a, 15b, 15c, 1
As shown in FIG. 21, 5d and 15e are covered with a rear cover 17 which abuts and is fixed on the end plate 12h of the developing frame 12.

From the above-described embodiments of the present invention, the contents of the present invention are summarized as follows.

The toner supply container TY is the image forming apparatus main body 1
4, the slide member 160 on the upper portion of the developer container lid 29 slides, and the developer container lid 2 is moved.
Nine supply ports 29c (see FIG. 24) are opened and connected to a discharge opening (not shown) for discharging toner from the toner supply container. When the toner supply container TY is not installed, the supply port 29a of the developing container cover 29 is in a closed state. The guide member 29d integrated with the developing container lid 29 is the same as that shown in FIG.
Developer concentration detecting means 1 on a stirring screw 10g shown in FIG.
The opening cross section gradually decreases as approaching the front end so that toner is supplied near 50 (TP in the figure). The replenished toner is conveyed along the arrow shown in FIG. 25 while being stirred with the carrier. The sufficiently stirred developer (toner and carrier) is detected by the developer concentration detecting means 150. The mixture ratio of the carrier and the toner is always detected, and the toner is supplied from the toner supply container TY in accordance with the consumption of the toner so that the mixture ratio becomes constant.

[0088]

As described above, according to the present invention,
By supplying the developer to the stirring / transporting member at a position farther from the developer carrying member except for the stirring / transporting member located near the developer carrying member in the developing container, the developer is sufficiently stirred and the concentration becomes constant. The developer can be supplied to the developer carrier.

Further, by supplying the developer to the downstream of the stirring / conveying member in the conveying direction with respect to the developer concentration detecting means, erroneous detection by the developer concentration detecting means is prevented and the developer concentration is stabilized. In addition, it is possible to prevent the toner from scattering in the developing container.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electrophotographic image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a process cartridge of the apparatus of FIG.

FIG. 3 is a front view of the process cartridge of FIG. 2;

FIG. 4 is a right side view of the process cartridge of FIG. 2;

FIG. 5 is a left side view of the process cartridge of FIG. 2;

FIG. 6 is a plan view of the process cartridge of FIG. 2;

FIG. 7 is a rear view of the process cartridge of FIG. 2;

8 is a perspective view of the process cartridge of FIG. 2 as viewed from the front right side.

FIG. 9 is a perspective view of the process cartridge of FIG. 2 viewed from the rear left.

FIG. 10 is a perspective view of the process cartridge of FIG.

FIG. 11 is a front view of a charging unit of the process cartridge of FIG. 2;

FIG. 12 is a front view of the charging unit of FIG. 11 with a blade removed.

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

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

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

FIG. 16 is a perspective view showing the inside 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 sleeve.

FIG. 19 is a longitudinal sectional view showing a support and a driving device of the electrophotographic photosensitive drum.

FIG. 20 is a perspective view of a driving-side drum flange.

FIG. 21 is a perspective view of the process cartridge viewed from below and obliquely rearward with the rear cover removed.

FIG. 22 is a schematic perspective view illustrating a mounting portion of a process cartridge.

FIG. 23 is a cross-sectional view illustrating a developing unit and a photosensitive drum.

FIG. 24 is a longitudinal sectional view of the developing unit.

[Explanation of symbols]

B (BY, BM, BC, BB) process cartridge C charging unit D developing unit E driving unit SC swing center SLv pressing center TP toner supply position 1Y, 1M, 1C, 1Bk scanning optics System 2: recording medium 3a: feeding cassette, 3b: pickup roller, 3
d, 3f: conveyance roller, 3g: registration roller pair, 3c
... Retard roller pair, 3h, 3i ... Discharge roller pair, 4 ...
Intermediate transfer device, 4a ... intermediate transfer belt, 4b ... drive roller, 4c # driven roller, 4d ... secondary transfer opposing roller,
4Y, 4M, 4C, 4Bk Transfer roller 5 Fixing device 6 Tray 7 Photoconductor drum, 7a Drum cylinder 8 Magnetic bran charger, 8a Charging roller, 8a1 Seal portion, 8a2 Journal portion, 8b … Magnet, 8
c: regulating blade, 8d: supporting metal plate, 8j, 8k: small screw, 8n: spacer roller 10: developing means, 10a: developing container, 10c: magnet, 10d: developing sleeve, 10d1: journal part 1
0e: regulating blade 10f: partition wall, 10g, 10h: stirring screw, 10j: spacer roller, 11: conductive brush 12, developing frame, 12a: guide portion, 12b: drum shaft support hole, 12c: groove, 12d: hole, 12e ... the seat,
12f lower part, 12g side part, 12i end plate part, 12 ...
Hole, 12k: Hole, 12m: Hole, 12n: Spring seat, 12p
... Shaft, 12q ... Hole 13 ... Charging frame, 13a ... Lower edge, 13b ... Upper and lower walls,
13c: corner portion, 13d: top plate portion, 13e, 13f: member mounting portion, 13g: blade mounting seat portion, 13h: female screw hole, 13i: dowel, 13j: hole, 13n: transfer opening, 1
3p: hole 14: device body, 14a: cartridge mounting portion, 14b
... Cartridge member, 14c Guide 15a ... Drive gear, 15b ... Development sleeve gear, 15c
... 2nd gear, 15c1 ... small gear, 15c2 ... large gear, 1
5d, 15e: Stirring gear 16: Front cover, 17: Rear cover, 17a: Shaft support 19g, 19h: Support shaft 20: Charging roller bearing, 21b, 21g: Seal material 22: Charging roller bearing 23: End cover, 23a: Hole 24: Gear unit 26a: Cylindrical shaft 27: Support shaft 29: Developer container lid, 29b: Guide, 29c: Supply port, 29d: Guide member 31: Image forming unit, 31Y, 31M, 31C, 31Bk
... Image forming unit 32 ... Swing arm, 32a ... Bearing hole, 32b ... Stopper unit, 32c ... Spring seat 33 ... Support shaft 35 ... Compression coil spring 36 ... Development sleeve cover 37 ... Drum flange, 37a ... Mounting part, 37b ... Collar 37c Journal part 37d Coupling convex part 39 Developing part coupling 40 Secondary transfer roller 42 Drum shaft 42a Tip part 43 Pin 45 Motor 46 Pinion 47 Intermediate gear 48 Large Gear 49 ... Large gear shaft 51 ... Bearing 52 ... Coupling concave shaft, 52a ... Coupling recess 53 ... Shaft retaining ring 54 ... Bearing case 55 ... Shaft support 56 ... Collar 57 ... Centering portion 101 ... Drum ground contact 102 ... Conductive bran contact 103: charging bias contact 104: developing bias contact 150: developer concentration detecting means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naofumi Horikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H077 AA01 AA11 AB02 AB12 AB13 AB15 AB18 AC02 AD06 BA09 DA10 DA42 DA51

Claims (6)

[Claims] 1. A developer container to which a developer is supplied, a plurality of agitating and conveying members for agitating and transporting the developer in the developing container, and a developer carrier for holding a predetermined amount of the developer in the developing container. Wherein the developer is supplied to any one of the plurality of agitating and conveying members except for the one arranged at a position closest to the developer carrier among the plurality of agitating and conveying members. Developing means provided with a guide member that performs the following operations. 2. The developing means according to claim 1, wherein said guide member is integrated with a developing container lid. 3. The developing means includes a first stirring / transporting member disposed at a position near the developer carrier and a second stirring / transporting member disposed at a position remote from the development carrier. The developing unit according to claim 1, wherein the guide member replenishes the developer to the second stirring and conveying member. 4. A developer concentration detecting means is provided on a conveying path of the stirring member to which the developer carrying member is supplied, and the guide member is provided on the downstream side in the developer conveying direction as viewed from the developer concentration detecting means. 2. The developing means according to claim 1, wherein a developer supply position is provided. 5. A process cartridge comprising: at least an image carrier; and a developing unit according to claim 1, which is disposed around the image carrier. 6. An image forming apparatus main body, and a process cartridge according to claim 5, which is detachable from the image forming apparatus main body, and records a developer image formed on an image carrier of the process cartridge. An electrophotographic image forming apparatus, which forms an image by transferring the image to a medium.