JPH1020746A - Process cartridge and electrophotographic image forming apparatus - Google Patents

Abstract

(57) Abstract: In order to reduce the size of a process cartridge, cleaning means is eliminated, and a toner chamber (12) is arranged above a developing chamber (11) having a developing roller (13). In the above configuration, it is an object to realize a configuration in which a small amount of toner is supplied from the toner chamber 12 to the developing chamber 11 in a constant amount. SOLUTION: A process cartridge developing chamber 11 has a developing roller 13 and a coating roller 14, and a toner chamber 12 is disposed on the developing chamber. The toner chamber has a shutter mechanism 43 for supplying a small amount of toner to the developing chamber at a constant rate. The shutter mechanism opens and closes the opening by reciprocating the shutter member 43c connected to the arm member 43b through the opening 18a on the bottom surface of the toner chamber. A small amount of toner is sent from the toner chamber to the developing chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge used for an image forming apparatus such as a laser beam printer and a copying machine, and an image forming apparatus having this process cartridge detachably mounted.

[0002]

The present invention is a further development of the prior art described below.

According to the present invention, the toner is not applied to the developing roller and the coating roller as the developing members, the toner can be continuously circulated, and the toner tribo (charge amount per unit weight) is constant even after repeated use. As a result, it is an object of the present invention to provide a process cartridge having a constant development density.

[0004]

According to a first aspect of the present invention, an electrophotographic photosensitive member and a developing device for developing a latent image formed on the electrophotographic photosensitive member in a process cartridge detachable from an image forming apparatus main body. Means, wherein the developing means is provided with a toner chamber for storing toner adjacent to a developing chamber provided with a developing member, and has a shutter member for opening and closing an opening between the developing chamber and the toner chamber. A process cartridge characterized by the above-mentioned.

According to a second aspect of the present invention, the shutter member can be slid to at least a position to close an opening at the bottom of the developer accommodating portion and to a position to open the opening, and the sliding range includes an opening of the toner chamber. The process cartridge according to the first aspect, wherein the process cartridge covers the entire area of the bottom of the toner chamber.

According to a third aspect of the present invention, there is provided a process cartridge according to the first or second aspect, wherein one or more openings are provided, and one or more shutter members corresponding to each opening are provided. It is.

According to a fourth aspect of the present invention, in the process cartridge, the charging means, the developing means, and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachably mountable to an image forming apparatus main body. A process cartridge according to the first aspect of the invention.

According to a fifth aspect of the present invention, there is provided a prosthesis as set forth in the first aspect, wherein the developing chamber has a developing roller disposed close to an electrophotographic photosensitive member and a developing blade in contact with the developing roller. Ridge.

A sixth invention of the present invention is the process cartridge according to the fifth invention, wherein an application roller in contact with said developing roller is disposed in a developing chamber.

A seventh aspect of the present invention is the process cartridge according to the first aspect, wherein the opening between the developing chamber and the toner chamber is provided on a partition wall provided between the developing chamber and the toner chamber.

An eighth invention of the present invention is the process cartridge according to the first invention, wherein an opening between the developing chamber and the toner chamber is provided at a position far from the developing roller.

A ninth invention of the present invention is the process cartridge according to the seventh invention, wherein said partition wall is horizontal.

According to a tenth aspect of the present invention, in the process cartridge mounted on the image forming apparatus main body, the opening between the developing chamber and the toner chamber is disposed at a position different from a position directly above the developing roller. It is a process cartridge according to the invention.

An eleventh aspect of the present invention is the process cartridge according to the seventh aspect, wherein the width of the opening between the developing chamber and the toner chamber is equal to or less than half the width of the partition wall in the lateral direction.

In a twelfth aspect of the present invention, the shutter member is opened and closed by a driving device interlocked with a developing roller.
It is a process cartridge according to the invention.

According to a thirteenth aspect of the present invention, in the driving device for the shutter member, a boss provided at an eccentric position of an output side shutter gear of a gear train meshing with a developing roller gear fixed coaxially with the developing roller is movable. An arm provided with a long hole to be fitted in the radial direction is rotatably supported on a frame constituting the toner chamber, and is attached to a shutter member in a long hole provided at the other arm end coaxially fixed with the arm. The process cartridge according to the twelfth aspect, wherein the round pin is movably fitted.

According to a fourteenth aspect of the present invention, there is provided the process cartridge according to any one of the first to thirteenth aspects of the present invention, wherein the shutter member is provided with an uneven shape on the upper surface thereof so as to scratch the toner. .

According to a fifteenth aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium by detachably attaching a process cartridge, comprising: a. An electrophotographic photoreceptor, and a developing unit for developing a latent image formed on the electrophotographic photoreceptor, wherein the developing unit includes a toner chamber for storing toner adjacent to a developing chamber having a developing member. Mounting means for removably mounting a professional cartridge provided and having a shutter member for opening and closing an opening between the developing chamber and the toner chamber; b. An electrophotographic image forming apparatus having a pre-recording medium conveying means.

[0019]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus for forming an image on a recording medium using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge. A process cartridge system in which the cartridge is detachable from the image forming apparatus main body is employed. According to this process cartridge system, maintenance of the apparatus can be performed by the user himself without relying on a service person, so that operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

In such a process cartridge, there has been proposed a method in which, among the image forming processes, charging, exposure, development, transfer, and cleaning, the cleaning device is omitted and the transfer residual toner is collected by the developing device. By doing so, it is known that the cleaning unit can be omitted from the process cartridge to further reduce the size, and at the same time eliminate waste toner.

[0021]

Next, an embodiment of a process cartridge and an image forming apparatus according to the present invention will be described in detail with reference to the drawings.

(Embodiment) An embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram of a configuration of an image forming apparatus in which a process cartridge is mounted, FIG. 2 is an explanatory diagram of a configuration of a process cartridge, and FIGS.
FIG. 5 is an explanatory diagram of the configuration of the shutter mechanism.

Here, as the order of the description, first, the overall configuration of the image forming apparatus and the process cartridge will be described, and then the configuration of the shutter mechanism will be described.

[Overall Configuration] As shown in FIG. 1, an image forming apparatus A is a laser beam L based on image information from an optical system 1.
To form an electrostatic latent image on the photosensitive drum 7 serving as an image carrier, and an image of a developer (hereinafter referred to as toner) is formed on the photosensitive drum 7 Formed on (visualization). Then, in synchronization with the formation of the toner image, the recording medium 2 is transported from the paper feed cassette 3a by the transport unit 3 including a pickup roller 3b, and the toner image formed on the photosensitive drum 7 is transferred to a transfer roller as a transfer unit. The recording medium 2 is transferred to the fixing unit 5 by applying a voltage to the recording medium 4 and guided by the guide plate 3d.

The fixing means 5 comprises a driving roller 5a and a fixing roller 5b having a built-in heater, and applies heat and pressure to the recording medium 2 passing therethrough to fix the transferred toner image. Then, the recording medium 2 is transported by the transport roller 3e through the reversing path 3f and is discharged to the discharge unit 6.

(Process Cartridge) Next, the process cartridge will be described. The process cartridge has an image bearing member and at least one process means. In this embodiment, a developing means is indispensable. Here, as the process means other than the above, for example, there is a charging means for charging the surface of the image carrier.

As shown in FIGS. 1 and 2, the process cartridge B of this embodiment includes a charging means 8 and a developing means 10 containing toner (developer) around a photosensitive drum 7 as an image carrier. They are arranged and assembled integrally into one frame to form a cartridge, which is configured to be detachable from the apparatus main body 17.

In the present embodiment, since the toner chamber 12 is disposed above the developing section, the pickup roller 3b can be placed at the position shown in the drawing, and the size of the apparatus main body 17 is reduced.

Next, the structure of each part of the process cartridge B will be described.

The photosensitive drum 7 according to the present embodiment is constructed by applying an organic photoconductive layer to the outer peripheral surface of an aluminum cylinder, and gear flanges fixed to both ends of the photosensitive drum 7 as shown in FIG. By transmitting the drive of a drive motor (not shown) to the gear formed at 7a, the photosensitive drum 7 is rotated in the direction of arrow K1 in FIG. 2 in accordance with the image forming operation.

(Charging Means) The charging means 8 employs a contact charging method, in which a conductive roller is brought into contact with the photosensitive drum 7 and a voltage is applied to the conductive roller to thereby charge the photosensitive drum 7. Surface is uniformly about -600 to -700
V is charged.

The process cartridge B has an exposure window 16 for irradiating the photosensitive drum 7 charged by the charging means 8 with image light from the above-described scanner unit 1 to form a latent image. Is provided.

(Developing Means) Here, the developing means according to the present invention will be described.

In order to visualize the latent image, a developing means 10 for enabling toner development is provided. 2 is a longitudinal sectional view of the process cartridge, FIG. 3 is a sectional view of the toner chamber, FIG. 4 is a sectional view of the shutter member 43c, and FIG. 5 shows a driving mechanism of the shutter mechanism.

The developing means 10 is constituted by a hollow frame, and the inside thereof is divided into a developing chamber 11 and a toner chamber 12,
An opening 12a is provided between the two. This opening 1
2a is a partition wall 12 for separating the developing chamber 11 and the toner chamber 12.
It is provided in a part of c. The partition wall 12c faces in the horizontal direction in the process cartridge B mounted on the apparatus main body 17. Further, a shutter mechanism 43 for supplying toner to the developing chamber 11 is provided in the toner chamber 12. A shutter member 43c for opening and closing the opening 12a is provided at the bottom of the toner chamber 12 so as to be movable in a direction indicated by an arrow C in FIG. The width of the shutter member 43c in the short direction (the direction of arrow C) is the partition wall 12c.
The opening 12a is larger than the width of the opening 12a
Is not more than half the width of the partition wall 12c. This opening 12a is located at a position distant from the developing roller 13,
In the process cartridge B (see FIG. 2) attached to the apparatus main body 17, it is located immediately above the coating roller 14 on the side opposite to the side in contact with the developing roller 13. As shown in FIGS. 2 and 3, the shutter mechanism 43 reciprocates a shutter member 43c connected to an arm member 43b swinging about a shaft 43a in the direction of arrow C along the bottom surface of the toner chamber 12. Thus, the opening 12a between the developing chamber 11 and the toner chamber 12 is opened and closed, the toner is freely dropped from the toner chamber 12, and a small amount of the toner is supplied to the developing chamber 11. The connection between the arm member 43b and the shutter member 43c is such that the round pin 44 fitted into the round hole of the shutter member 43c rotates in the long hole 43b1 in the longitudinal direction of the arm member 43b and moves in the long hole 43b1. I have.

The shutter member 43c and the arm member 4
3b, the shaft 43a is made of a material such as polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (HIPS), polyacetal (POM), and the arm member 43b and the shaft 43a are integrally formed.

Opening / closing member 43 of the shutter member 43c
c1 has a rectangular cross section as shown in FIG. 4 (4-1), a rectangular or triangular shape (not shown) inclined toward the opening as shown in FIG. 4 (4-4). is there. Also, a projection 43c2 perpendicular to the plane of the paper of FIG. 4 (4-2) or a column or a quadrangular prism shown in (4-2) of FIG. 4, (4-3) of FIG.
The shutter member 43c is formed so that the surface facing the inside of the toner chamber 12 has an irregular shape, such as a cone or a pyramid shown in FIG. The toner is scraped.

The arm member 43b integrally formed with the shaft 43a is provided at two locations in the longitudinal direction at a certain distance from the side wall 12b of the toner chamber 12 (see FIG. 3). In the case where the space between the side wall 12b and the arm member 43b is a narrow space, it is prevented from being aggregated.

One end of a shaft 43a serving as a swing center of the arm member 43b is connected to a transmission member 43d rotatably mounted through a side wall 12b of the toner chamber 12 by snap fit. Inner wall 12b
Attached to. The other end is rotatably supported by a concave groove 43e provided in the inner wall 12b of the toner chamber 12.

On the other hand, as shown in FIG. 5, the drive transmission means is a developing roller gear 13 in which a gear flange 7a fixed to one end of the photosensitive drum 7 is concentrically fixed to one end of the developing roller 13.
a, the developing roller gear 13a meshes with a coating roller gear 14a concentrically fixed to one end of the coating roller 14,
Next, the application roller gear 14 a is moved to the side wall 12 of the toner chamber 12.
The shutter gear 43f, which is also rotatably mounted on the side wall 12b, is driven via a stepped idler gear 14b, which is rotatably mounted outside of b. Further, a boss 43f1 integrally formed with the shutter gear 43f is engaged with a long hole 43d2 provided in an arm portion 43d1 of a transmission member 43d fixed to the shaft 43a with a predetermined radial distance from the rotation center of the shutter gear 43f. It is constituted by that.

The drive transmitting means reciprocates the shutter member 43c connected to the arm member 43b swinging about the shaft 43a in the direction of the arrow C along the bottom surface of the toner chamber 12, thereby developing the developing chamber. The opening 12a between the toner chamber 11 and the toner chamber 12 is opened and closed, the toner is freely dropped from the toner chamber 12, and a small amount of toner is supplied to the developing chamber 1 by a small amount.
1 can be supplied. Also, the shutter member 43
c moves the entire area of the bottom surface of the toner chamber 12 and transfers the toner to the opening 1.
Almost no toner remains in the toner chamber 12 because it is collected near 2a.

The developing chamber 11 is provided with a developing roller 13 which is a developer carrier rotatably driven in the direction of arrow K2, in contact with the developing roller 13, and with respect to the moving direction of the peripheral surface of the developing roller 13. A coating roller 14 that is driven to rotate in the same direction as the developing roller 13 so that the peripheral surface moves in the counter direction (the direction of the arrow K3) is rotatably mounted on the frame of the process cartridge B. The small amount of toner supplied into the developing chamber 11 is conveyed by the rotation of the coating roller 14 and further conveyed to a contact portion between the coating roller 14 and the developing roller 13. Is applied to the developing roller 13. Further, the toner conveyed to the developing roller 13 moves to a latent image portion of the photosensitive drum 7 via a nip portion with the developing blade 15 and is visualized.

In the present embodiment, the coating roller 14 rotates in the same direction as the rotation direction K1 of the developing roller 13, but may rotate in the opposite direction if a difference in peripheral speed is provided. .

[0044]

As described above, the first embodiment according to the present application is described.
According to the invention, in a process cartridge in which an electrophotographic photosensitive member and a developing unit are integrally mounted and a cleaning unit is eliminated, a toner chamber for storing toner is disposed above the developing chamber, and a shutter member is provided in the toner chamber. By opening and closing the opening between the toner chamber and the developing chamber, the toner can be freely dropped from the toner chamber into the developing chamber, and a small amount of toner can be supplied. This makes the tribo applied to the toner constant,
This has the effect of making the image density uniform. Further, since the toner in the toner chamber can be sent out without remaining, the toner chamber can be made smaller, and the process cartridge can be downsized.

According to a second aspect of the present invention, in the first aspect, the shutter member is slidable so that the entire area of the bottom of the toner chamber is slid so that the toner in the toner chamber is supplied to the developing chamber without remaining. The third invention according to the present application, which can take a possible mode, is characterized in that, in the first or the second invention, a plurality of shutter members are provided with a plurality of openings of the toner chamber and the development space, and a longitudinal direction of the development member is provided. Of the toner is measured and the toner is supplied uniformly.

The fourth invention according to the present application is suitable for applying the first invention to a process cartridge having a charging means.

According to a fifth aspect of the present invention, in the first aspect, the developing chamber includes a developing roller disposed close to the electrophotographic photosensitive member, and a developing blade in contact with the developing roller. As a result, a suitable development result is obtained.

According to a sixth aspect of the present invention, in the fifth aspect, the coating roller in contact with the developing roller is disposed in the developing chamber, so that the uniformity of toner application to the developing roller is increased. Thus, the degree of freedom in selecting the positions of the toner chamber and the opening of the developing space increases, and the degree of freedom in designing the shape of the developing chamber increases.

According to a seventh aspect of the present invention, in the first aspect, the opening between the developing chamber and the toner chamber is provided on a partition wall provided between the developing chamber and the toner chamber.
It is easy to select the position of the opening and to arrange the shutter member.

According to an eighth aspect of the present invention, in the first aspect, the opening between the developing chamber and the toner chamber is provided at a position far from the developing roller, so that the amount of toner applied to the developing roller can be reduced. The falling toner does not affect the distribution by pressing.

According to a ninth aspect of the present invention, in the seventh aspect, the partition member is in a horizontal direction, so that the toner in the toner chamber does not move in the horizontal direction due to its own weight, so that the shutter member can be more effectively used. Acts and toner does not block.

According to a tenth aspect of the present invention based on the fifth aspect, in the process cartridge mounted on the image forming apparatus main body, the opening between the developing chamber and the toner chamber is located at a position different from immediately above the developing roller. , The weight of the toner from the toner chamber to the developing chamber is not applied to the developing roller, so that the toner layer on the developing roller can be favorably maintained.

According to an eleventh aspect of the present invention, in the seventh aspect, the width of the opening between the developing chamber and the toner chamber is less than half the width of the partition wall in the lateral direction. Can be easily set, and the shutter member can fully open and fully close the opening.

According to a twelfth aspect of the present invention, in the fifth aspect of the invention, the shutter member is opened and closed by a driving device interlocked with the developing roller, so that the shutter member always moves during the developing process. Therefore, the toner supply from the toner chamber to the developing chamber is always performed continuously.

In a thirteenth aspect of the present invention based on the twelfth aspect, in the twelfth aspect, the drive unit for the shutter member is configured such that the eccentric position of the output-side shutter gear of the gear train meshed with the developing roller gear fixed coaxially with the developing roller. The arm provided with an elongated hole in which the boss provided on the arm is movably fitted is rotatably supported on a frame constituting the toner chamber, and is provided at the other arm end coaxially fixed with the arm. By movably fitting a round pin attached to the shutter member to the hole, the shutter member is a movement similar to a harmonic movement,
Despite the reciprocation, no impact is given to the developing means. Therefore, the image quality is not affected.

According to a fourteenth aspect of the present invention, in the invention according to any one of the first to thirteenth aspects, a toner chamber is provided by forming an uneven shape on the upper surface of the shutter member so as to scratch the toner. The toner is not stirred in the toner chamber.

According to a fifteenth aspect of the present invention, there is provided an electrophotographic image forming apparatus which detachably attaches a process cartridge and forms an image on a recording medium, comprising: a. An electrophotographic photoreceptor, and a developing unit for developing a latent image formed on the electrophotographic photoreceptor, wherein the developing unit includes a toner chamber for storing toner adjacent to a developing chamber having a developing member. Mounting means for removably mounting a professional cartridge provided and having a shutter member for opening and closing an opening between the developing chamber and the toner chamber; b. By using the electrophotographic image forming apparatus having the pre-recording medium conveying means, an image having a uniform image density can be obtained and the process cartridge can be made smaller, so that the image forming apparatus body can be made smaller.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of a process cartridge according to the present invention.

FIG. 3 is a longitudinal sectional view along a longitudinal direction of a developing chamber in the present invention, and is a sectional view taken along line DD of FIG. 2;

FIG. 4 shows (4-1), (4-2), (4-3), (4-
4) are cross-sectional views of the shutter member according to the present invention.

FIG. 5 is a longitudinal sectional view of a driving unit of the process cartridge according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical system 2 ... Recording medium 3 ... Conveying means 3a ... Paper feed cassette 3b ... Pickup roller 3d ... Guide plate 3e ... Conveying roller 3f ...
Reversing path 4 Transfer roller 5 Fixing means 5a Driving roller 5b Fixing roller 7 Photoconductor drum 7a Gear flange 8 Charging means 10 Developing means 11 Developing chamber 12 Toner chamber 12a Opening 12b Side wall 12
c: partition wall 13: developing roller 13a: developing roller gear 14: coating roller 14a: coating roller gear 14b
Idler gear 15 Developing blade 16 Exposure window 17 Device main body 43 Shutter mechanism 43 a Shaft 43 b Arm member 43 c Shutter member 43 b 1 Slotted hole 43 c
DESCRIPTION OF SYMBOLS 1 ... Opening / closing member 43c2 ... Square pillar or protrusion 43c3 ... Cone or pyramid or protrusion 43d ... Transmission member 43d1 ... Arm part 43d2 ... Long hole 43f ...
Shutter gear 43f1 Boss 44 Round pin A Image forming apparatus B Process cartridge L Laser light

Claims (15)

[Claims] 1. A process cartridge detachable from a main body of an image forming apparatus, comprising: an electrophotographic photoreceptor; and a developing unit for developing a latent image formed on the electrophotographic photoreceptor. A process cartridge having a toner chamber for storing toner adjacent to a developing chamber provided with a member, and a shutter member for opening and closing an opening between the developing chamber and the toner chamber. 2. The shutter member is slidable to at least a position to close an opening at the bottom of the developer accommodating portion and to a position to open the opening, and the sliding range extends over the entire area of the bottom of the toner chamber including the opening of the toner chamber. The process cartridge according to claim 1, wherein the process cartridge extends. 3. The process cartridge according to claim 1, wherein said opening is one or more, and one or more shutter members corresponding to each opening are provided. 4. The process according to claim 1, wherein the process cartridge comprises a charging unit, a developing unit, and an electrophotographic photosensitive member integrally formed as a cartridge, and the cartridge is detachably mountable to an image forming apparatus main body. cartridge. 5. The process cartridge according to claim 1, wherein the developing chamber includes a developing roller disposed close to the electrophotographic photosensitive member, and a developing blade in contact with the developing roller. 6. The process cartridge according to claim 5, wherein an application roller in contact with said developing roller is provided in a developing chamber. 7. The process cartridge according to claim 1, wherein the opening between the developing chamber and the toner chamber is provided on a partition wall provided between the developing chamber and the toner chamber. 8. The process cartridge according to claim 1, wherein an opening between the developing chamber and the toner chamber is provided at a position far from the developing roller. 9. The partition wall is horizontal.
The process cartridge described in. 10. The process cartridge according to claim 5, wherein the opening between the developing chamber and the toner chamber is disposed at a position different from immediately above the developing roller in the process cartridge mounted on the image forming apparatus main body. . 11. The process cartridge according to claim 7, wherein the width of the opening between the developing chamber and the toner chamber is equal to or less than one half of the partition wall in the lateral direction. 12. The process cartridge according to claim 5, wherein said shutter member is opened and closed by a driving device interlocked with a developing roller. 13. A shutter driving device according to claim 1, wherein said boss provided at an eccentric position of an output-side shutter gear of a gear train meshing with a developing roller gear fixed coaxially with said developing roller is movably fitted. The arm provided in the radial direction is rotatably supported on the frame constituting the toner chamber, and the round pin attached to the shutter member is freely movable in the long hole provided on the other arm end coaxially fixed with the arm. 13. The process cartridge according to claim 12, which is fitted. 14. The process cartridge according to claim 1, wherein an uneven shape is provided on an upper surface of the shutter member so as to scratch the toner. 15. An electrophotographic image forming apparatus which detachably attaches a process cartridge and forms an image on a recording medium, comprising: a. An electrophotographic photoreceptor; and a developing unit for developing a latent image formed on the electrophotographic photoreceptor, wherein the developing unit is adjacent to a developing chamber provided with a developing member and stores a toner. Mounting means for removably mounting a process cartridge having a shutter member for opening and closing an opening between the developing chamber and the toner chamber; b. An electrophotographic image forming apparatus having a pre-recording medium conveying means.