JP2003122120A - Developing device, process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of reducing adverse influence exerted on image formation even when the amount of toner in a toner storage part is fluctuated, and making the driving torque small and reducing the adverse influence exerted on the image formation even in the case of using a large- capacity toner cartridge, and a process cartridge or an image forming device having the developing device. SOLUTION: In a typical constitution of the developing device, the process cartridge and the image forming device to solve the problem is characterized in that the developing device can be attached to/detached from the image forming device and has a toner carrier for performing developing on an electrophotographic photoreceptor with toner, a regulation means for forming a toner layer on the toner carrier, the toner storage part, a 1st frame body holding the toner carrier and the regulation means, and a 2nd frame body integrated with or fixed in the toner storage part and pressuring the toner carrier to the electrophotographic photoreceptor, then the 1st frame body is held to slide to move linearly with respect to the 2nd frame body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic image forming apparatus, and a process cartridge or image forming apparatus having the developing device.

[0002]

2. Description of the Related Art FIG. 13 shows a typical example of a process cartridge using a conventional developing device. In the figure, on the photosensitive unit B of the process cartridge, the photosensitive drum 10 that forms an electrostatic latent image, the charging unit 11 that uniformly charges the surface of the photosensitive layer, and the photosensitive drum 10 that is not transferred to the recording medium.
A cleaning unit 14 for scraping off the residual toner adhering on the surface of the photosensitive drum 10 and storing it in the waste toner container 12 is provided. Further, the developing device unit A includes a toner container 21 containing toner, a developing roller 20 for supplying toner to the electrostatic latent image formed on the photoconductor drum 10 to form a visible image, and a toner. A developing blade 22 that forms a toner layer on the surface of the developing roller 20 by applying a triboelectric charge to the developing roller 20, a jetting prevention sheet 25 that prevents toner leakage in the radial direction of the developing roller 20, and the like are arranged. The developing device unit A and the photoconductor unit B are engaging pins.
It is rotatably connected at 31. A biasing spring 32 is provided between the developing device unit A and the photoconductor unit B.

In FIG. 13, the photosensitive drum 10 is rotating clockwise. A constant voltage is applied to the charging means 11, and when the photoconductor drum 10 comes into contact, the surface of the photoconductive layer of the photoconductor drum 10 with which the photoconductor drum 10 comes into contact is uniformly charged. Then optical means 1
By irradiating the photoconductor drum 10 with the laser beam L corresponding to the image information from the photoconductor drum 10 through the exposure opening 2, an electrostatic latent image is formed on the photoconductor drum 10. After that, a toner image is formed on the photosensitive drum 10 by the developing means.

The developing means sends the toner in the toner container 21 to the developing roller 20 by rotating the toner feeding member 23. Then, the developing roller 20 having the fixed magnet 29 built therein is rotated, and at the same time, a toner layer to which a triboelectric charge is applied by the developing blade 22 is formed on the surface of the developing roller 20. The developing roller 20 maintains a constant clearance via a spacer roller 26, and is biased by a biasing spring 32 to a photosensitive drum.
The toner that is pressed by the surface 10 and is formed on the surface is supplied to the developing area of the photosensitive drum 10. A toner image is formed by transferring the toner to the photosensitive drum 10 according to the electrostatic latent image. Here, the developing blade 22 defines the amount of toner on the peripheral surface of the developing roller 20 and imparts triboelectric charge. Further, in the vicinity of the developing roller 20, a toner stirring member for circulating the toner in the developing chamber.
24 is attached so that it can rotate.

A voltage having a polarity opposite to that of the toner image is applied to the transfer roller 3 provided in the main body of the image forming apparatus to transfer the toner image formed on the photosensitive drum 10 to the recording medium 4, and then the cleaning means 14 is used. The residual toner on the photoconductor drum 10 is removed by. Here, the cleaning means 14 scrapes off the toner remaining on the photosensitive drum 10 by an elastic cleaning blade 14a provided in contact with the photosensitive drum 10 and collects it in the waste toner container 12.

[0006]

However, in the above-described conventional developing device, since the weight of the toner in the toner container 21 is overlaid on the pressure that presses the developing roller 20 against the photosensitive drum 10, image formation is performed. Due to the consumption of the toner inside, the pressure for pressing the developing roller 20 against the photosensitive drum 10 changes, and the driving torque of the developing device also changes accordingly. Then, these variations may cause variations in the image density.

Further, when a large capacity toner cartridge is constructed, a larger amount of toner weight is applied to the pressure for pressing the developing roller 20 against the photosensitive drum 10, so that the driving torque is further increased. Further, a large load is applied to the bearing supporting the developing roller 20 and the spacer roller, so that the bearing and the spacer roller may be worn or deformed to affect the life.

The present invention has been made in view of the above circumstances, and even if the amount of toner in the toner storage portion fluctuates, it does not have a bad influence on image formation, and the driving torque is small even in a large capacity toner cartridge. Further, it is an object of the present invention to provide a developing device capable of reducing adverse effects on image formation and a process cartridge or an image forming device having the developing device.

[0009]

In order to solve the above-mentioned problems, a developing device, a process cartridge, and an image forming apparatus according to the present invention typically have a developing device detachable from the image forming apparatus. Holding a toner carrier for developing on the electrophotographic photosensitive member with toner, a regulation unit for forming a toner layer on the toner carrier, a toner accommodating portion, and the toner carrier and the regulation unit. A first frame body and a second frame body that is integrally or fixed to the toner storage unit and presses the toner carrier against the electrophotographic photosensitive member, and the first frame body is the second frame body. It is characterized in that it is held so as to be linearly slidable with respect to.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a developing device, a process cartridge and an image forming apparatus according to the present invention will be described with reference to the drawings.

(Overall Configuration of Image Forming Apparatus) First, the overall configuration of the image forming apparatus will be described with reference to FIG. Figure 12
FIG. 1 is an overall configuration diagram of an image forming apparatus according to this embodiment.
The laser beam printer P shown in the figure uses a recording medium 4 (for example, recording paper, OH, etc.) by an electrophotographic image forming process.
An image is formed on a P sheet, cloth, etc.).

The surface of the photosensitive drum 10, which is a drum-shaped electrophotographic photosensitive member, is uniformly charged by the charging means 11. The photoconductor drum 10 is irradiated with laser light L corresponding to image information from the optical means 1 to form a latent image on the photoconductor drum 10 according to the image information. The toner image is formed by developing the latent image on the photosensitive drum 10 formed here by a developing device described later.

On the other hand, in synchronization with the formation of the toner image, the recording medium 4 set in the feeding cassette 6a is reversely conveyed by the pickup roller 6b, the conveyance guide 6c, and the registration roller pair 6e. Then, it passes through a nip portion formed by the photosensitive drum 10 and the transfer roller 3 to which a constant voltage is applied. At this time, the toner image developed on the photosensitive drum 10 is transferred to the recording medium 4. The recording medium 4 to which the toner image has been transferred is conveyed to the fixing unit 5 by the conveyance guide 6f.
The fixing unit 5 has a driving roller 5c and a fixing roller 5b containing a heater 5a therein, and applies heat and pressure to the recording medium 4 passing through the nip portion to fix the transferred toner image. Then, the recording medium 4 is ejected by a pair of discharge rollers
It is conveyed by i and discharged to the discharge tray 7.

(Process Cartridge) Next, the process cartridge C will be described with reference to FIG. In the figure, a photosensitive drum B for forming an electrostatic latent image on a photosensitive drum unit B of a cartridge, a charging means 11 for uniformly charging the surface of a photosensitive layer, and a photosensitive drum 10 without being transferred to a recording medium. Residual toner on top of the photoconductor drum
A cleaning unit 14 for scraping off from the surface and storing in a waste toner container 12 is arranged.

In the developing device unit A, a toner container 21 containing toner, a developing roller 20 for supplying toner to the electrostatic latent image formed on the photosensitive drum 10 to form a visible image, A developing blade 22 for applying a triboelectric charge to the toner and forming a toner layer on the surface of the developing roller 20 is arranged. A jetting prevention sheet 25 that seals the developing roller 20 and the first frame body 40 and the second frame body 50 is provided in the lower opening between the developing roller 20 and the developing roller 20 to prevent toner leakage in the radial direction. It has a function to do.

In FIG. 1, the photosensitive drum 10 is rotating clockwise. A constant voltage is applied to the charging means 11, and when the photoconductor drum 10 comes into contact, the surface of the photoconductive layer of the photoconductor drum 10 with which the photoconductor drum 10 comes into contact is uniformly charged. Then optical means 1
By irradiating the photoconductor drum 10 with the laser beam L corresponding to the image information from the photoconductor drum 10 through the exposure opening 2, an electrostatic latent image is formed on the photoconductor drum 10. After that, a toner image is formed on the photosensitive drum 10 by the developing means.

The developing means sends the toner in the toner container 21 to the developing roller 20 by rotating the toner feeding member 23. Then, the developing roller 20 having the fixed magnet 29 built therein is rotated, and at the same time, a toner layer to which a triboelectric charge is applied by the developing blade 22 is formed on the surface of the developing roller 20. The developing roller 20 is pressed against the photoconductor drum 10 by an urging spring 32 (see FIG. 4) while maintaining a certain clearance via the spacer roller 26, and the toner formed on the surface is developed on the photoconductor drum 10. Supply to the area. And
A toner image is formed by transferring the toner to the photosensitive drum 10 according to the electrostatic latent image. Here, the developing blade 22 defines the amount of toner on the peripheral surface of the developing roller 20 and imparts triboelectric charge. Further, a toner stirring member 24 for circulating the toner in the developing chamber is rotatably attached near the developing roller 20.

A voltage having a polarity opposite to that of the toner image is applied to the transfer roller 3 provided in the main body of the image forming apparatus to transfer the toner image formed on the photosensitive drum 10 to the recording medium 4, and then the cleaning means 14 is used. The residual toner on the photoconductor drum 10 is removed by. Here, the cleaning means 14 scrapes off the toner remaining on the photosensitive drum 10 by an elastic cleaning blade 14a provided in contact with the photosensitive drum 10 and collects it in the waste toner container 12.

As shown in FIG. 1, the developing device unit A comprises a first frame body 40 and a second frame body 50. As shown in FIGS. 2 and 3, the first frame body 40 is composed of a moving frame body 41, a swing frame body 42 and slide frame bodies 43 arranged at both ends thereof, and each member is integrally formed. It is fixed and holds the developing roller 20 and the developing blade 22. The developing roller 20 has a bearing 27
Both ends of the swing frame 42 and the slide frame via the
It is rotatably supported by 43. At both ends of the developing roller 20, spacer rollers 26 which are substantially concentric with the developing roller 20 and whose outer diameter is larger than the outer diameter of the developing roller 20 by a specified gap are slidably provided. The developing blade 22 as a regulating means for regulating the thickness of the toner layer on the developing roller 20 is integrally molded or adhered to the developing blade sheet metal 28. The developing blade sheet metal 28 is fixed to the moving frame body 41, and the tip of the developing blade 22 is in contact with the developing roller 20.

As shown in FIG. 2, the first frame body 40 comprises a slide frame body 41, a right slide frame body 42, and a left slide frame body 43, and the respective members are integrally fixed. See also FIG.
As shown in FIG. 2, the cylindrical developing roller 20 has flange members 20a and 20b press-fitted at both ends, and is rotatably supported by the right slide frame body 42 and the left slide frame body 43 via bearings 27, respectively. . A fixed magnet 29 is provided inside the developing roller 20. Further, spacer rollers 26, which are substantially concentric with the developing roller 20 and have a larger outer diameter by a specified gap than the outer diameter of the developing roller 20, are slidably provided at both ends of the developing roller 20.

As shown in FIG. 4, the developing blade 22 for regulating the toner layer thickness on the developing roller 20 is a developing blade metal plate 28.
Is integrally molded or adhered to. Development blade sheet metal
28 is fixed to the slide frame 41, and the developing blade 22
The leading end of the roller contacts the developing roller 20. The first frame body 40 holding the developing roller 20 and the developing blade 22 is installed in the second frame body 50. Here, the second frame body 50 is fixed to the toner container 21. A biasing spring 32 is provided between the first frame body 40 and the second frame body 50, and the developing roller 20 provided on the first frame body 40 is fixed by the spacer roller 26 with a certain clearance. Is pressed against. In this embodiment, the second frame 50 is fixed to the toner container 21, but it may be formed integrally with the toner container 21.

As shown in FIG. 5 (a), slide planes 42a and 42b that define the sliding direction of the first frame 40 are provided in parallel on the substantially upper and lower surfaces of the right slide frame 42. On the other hand, when the first frame 40 is installed in the second frame 50, the right slide frame 42 has a portion facing the slide planes 42a and 42b,
Guide planes 51a and 51b are provided with a minute clearance. Further, similar slide planes and guide planes facing the slide planes are provided on substantially the upper and lower surfaces of the left slide frame body 43. Further, in order to position the second frame body 50 and the first frame body 40 in the longitudinal direction, the second frame body 50 is provided with a positioning boss 52, and the slide frame body 41 is provided with a positioning slot 41a for determining only the longitudinal direction. Is provided. With these configurations, the first frame 40 can linearly slide with respect to the second frame 50.

As another configuration, as shown in FIG. 5 (b), slide rail protrusions 42c, 42d for defining the sliding direction of the first frame 40 are provided on substantially the upper and lower surfaces of the right slide frame 42. , The slide rail recess 51 in the opposing portion of the second frame 50.
It is also possible to provide c and 51d. Also, the left slide frame
Similar slide rail projections and slide rail recesses facing the slide rail projections are also provided on substantially the upper and lower surfaces of 43. In the right slide frame 42, the slide contact portions are the tip portions 42e and 42f of the slide rail convex portions and the bottom portions of the slide rail concave portions.
51e and 51f (see FIG. 8). With this configuration, the areas of the slide surface and the guide surface can be reduced, and it becomes easy to form a highly accurate surface. It should be noted that the short width fitting portion of the rail of either the right slide frame 42 or the left slide frame 43 is used to position the first frame 40 and the second frame 50 in the longitudinal direction, and the short width of the other rail is set. The fitting portion may have a play in the longitudinal direction of the process cartridge.

FIG. 6 shows a toner seal structure of the first frame body 40 and the second frame body 50. Elastic seal members 44 are fixed to the short sides of both ends of the first frame 40 and elastic seal members 45 are fixed to the upper long sides with double-sided tape, and the receiving surface of the second frame 50 shown in FIG.
It is compressed at 57 and 58 to give a sealing effect. In FIG. 9, arrows s and t are elastic seal members on the short sides of both ends.
44, the compression direction of the elastic seal member 45 at the upper long side is shown. In the figure, the compression direction of the elastic seal member 45 is set to be substantially perpendicular to the sliding direction of the first frame body 40. This makes it possible to reduce the influence of the repulsive force of the elastic seal member 45 having a large compression area on the pressing force for pressing the developing roller 20 against the photoconductor drum 10 and stabilize the pressing force.

Further, the ejection preventing sheet 25 is fixed to the lower long side portion 54 of the second frame 50 by a double-sided tape so as to contact the developing roller 20, so that the toner leakage in the radial direction below the developing roller 20 is prevented. To prevent. By doing this, the first frame 40
Since it is not necessary to provide the elastic seal member on the lower surface in the longitudinal direction, the device can be downsized.

FIG. 10 shows toner seals on both ends of the developing roller 20. The magnetic seal 60 is provided with a plurality of magnetic poles on the surface 60a facing the surface of the developing roller 20.
It is a sealing means for adsorbing the toner by a magnetic curtain between and. The magnetic seal 60 is inserted and positioned in a recess (not shown) provided in the slide frame 41, and the developing blade sheet metal
It is pressed and fixed by 28. Since the developing roller 20 and the magnetic seal 60 are fixed to the same first frame body 40, even if the developing roller 20 follows the outer periphery of the photoconductor drum 10 and the first frame body 40 moves, The clearance between the magnetic seals 60 can be accurately set to a constant value. For this reason,
It is possible to favorably seal the toner on both ends of the developing roller 20 by the magnetic seal 60.

FIG. 11 shows a schematic diagram of the drive system of the developing roller 20. Drum gear 71 provided at the end of the photosensitive drum 10
The driving force is transmitted from an image forming apparatus (not shown) via the driving gear 70, and the photosensitive drum 10 is rotationally driven. On the other hand, the drum gear 71 rotationally drives the developing roller gear 72 provided coaxially with the developing roller 20. The arrow a in the figure indicates the direction of the acting force that acts on the developing roller gear 72 when the drive is transmitted from the drum gear 71 to the developing roller gear 72. At this time, when the angles of the slide planes 42a and 42b of the right slide frame body 42 and the left slide frame body 43 described above are perpendicular to the direction of the acting force, or when the acting force acts on the sliding plane, the first frame The angle is set so as to press the body 40 toward the photosensitive drum 10. In the figure, F is a force generated by the acting force acting on the developing roller gear 72, Fy is a component force of the reaction force F in the direction perpendicular to the guide plane 51b, and similarly Fx is a direction parallel to the guide plane 51b of the reaction force F. Is the component force of. The direction of this Fx is toward the photoconductor drum 10. By doing so, the pressing force between the developing roller 20 and the photoconductor drum 10 does not decrease due to the effect of the action force from the gear when driving the developing roller 20, and the spacer roller is acted by the action of a slight external force.
26 is not separated from the photoconductor drum 10.

In the above structure, the right slide frame body
42, all angles of the slide planes 42a, 42b, etc. of the left slide frame 43 are perpendicular to the direction of the acting force, or when the acting force acts on the sliding plane, the first frame 40 is moved to the photosensitive drum 10 The angle is set to push in the direction. As another configuration, the non-driving side left slide frame body 43, which is relatively less affected by the acting force, may be slid toward the photoconductor drum 10.

[0029]

As described above, the developing device, the process cartridge, and the image forming apparatus according to the present invention are integrally or fixed to the first frame for holding the toner carrier and the regulating means, and the toner storage portion. And a second frame for pressing the toner carrier against the electrophotographic photosensitive member, and by holding the first frame linearly slidably with respect to the second frame, It is possible to prevent the weight of the toner storage portion from being applied, and it is possible to prevent an excessive load from being applied to the bearing portion of the toner carrier and the contact portion between the toner carrier and the photoconductor. As a result, even if the amount of toner in the toner chamber fluctuates, there is little adverse effect on image formation, and even with a large capacity toner cartridge, the driving torque is small and the adverse effect on image formation can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a process cartridge.

FIG. 2 is a perspective view illustrating a first frame body.

FIG. 3 is a cross-sectional view illustrating a first frame body.

FIG. 4 is a perspective view illustrating a process cartridge.

FIG. 5 is an enlarged view of a main part for explaining a slide frame body.

FIG. 6 is a diagram of a first frame for explaining a toner seal configuration.

FIG. 7 is a diagram of a second frame for explaining the toner seal configuration.

FIG. 8 is a diagram of a second frame for explaining another toner seal structure.

FIG. 9 is a cross-sectional view illustrating a compression direction of a toner seal.

FIG. 10 is a diagram illustrating a configuration of toner seals at both ends of the developing roller.

FIG. 11 is a schematic diagram of a drive system of a developing roller.

FIG. 12 is an overall configuration diagram of an image forming apparatus according to the present embodiment.

FIG. 13 is a diagram showing a representative example of a process cartridge using a conventional developing device.

[Explanation of symbols]

A ... Developer unit B: Photoconductor unit C ... Process cartridge L ... Laser light 1 ... Optical means 2 ... Exposure opening 3 ... Transfer roller 4 ... Recording medium 5 ... Fixing means 5a ... heater 5b ... Fixing roller 5c ... Drive roller 6a ... Feed cassette 6b ... Pickup roller 6c ... Conveyance guide 6e ... Pair of registration rollers 6f ... Conveyance guide 6i ... Ejection roller pair 7 ... Ejection tray 10 ... Photosensitive drum 11 ... Charging means 12… Waste toner container 14… Cleaning means 14a ... Elastic cleaning blade 20 ... Developing roller 20a, 20b ... Flange member 21… Toner container 22… Development blade 23 ... Toner feeding member 24 Toner stirring member 25… Blowout prevention sheet 26… Spacer roller 27… Bearings 28… Development blade sheet metal 29… Fixed magnet 31… Engagement pin 32 ... bias spring 40… First frame 41… Slide frame 41a ... Slot 42 ... Right slide frame 42a, 42b ... Slide plane 42c, 42d ... Slide rail protrusion 42e, 42f ... Tip 43… Left slide frame 44, 45 ... Elastic seal member 50… Second frame 51a, 51b ... Guide plane 51c, 51d ... Slide rail recess 51e, 52f ... Bottom part 52… Positioning boss 54… Lower long side 57, 58… Receiving surface 60… Magnetic seal 60a: surface facing the developing roller 70… Drive gear 71… Drum gear 72 ... Developing roller gear

Continued front page    (72) Inventor Kazushi Watanabe             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H077 AA02 AA12 AA35 AB04 AB14                       AC03 AD06 AD13 AD17 AE03                       BA03 BA07 BA08 BA09 CA12                       CA15 EA11

Claims (8)

[Claims] 1. A developing device detachable from an image forming apparatus, comprising a toner carrier for developing an electrophotographic photosensitive member with toner, and a regulation for forming a toner layer on the toner carrier. A toner storage unit, a first frame body that holds the toner carrier and the regulating unit, and a unit that is integrally or fixed to the toner storage unit and that presses the toner carrier onto the electrophotographic photosensitive member. A developing device, comprising: two frame bodies, and the first frame body being held so as to be linearly slidable relative to the second frame body. 2. A seal member for preventing toner leakage is provided between the first frame body and the second frame body, and the seal member compresses in a direction substantially perpendicular to a moving direction of the first frame body. The developing device according to claim 1, wherein 3. A seal member for preventing toner leakage is provided between the first frame member and the second frame member, and the seal member has the first frame member at both longitudinal ends of the toner carrier. The developing device according to claim 1, which is fixed to a body. 4. A lower opening is provided between the toner carrier and the first frame and the second frame, and the seal member closing the lower opening is a sheet-like member, and one end thereof is 4. The developing device according to claim 1, wherein the developing device is attached to a second frame body, and the other end is in contact with the toner carrier. 5. An urging means for urging the first frame member toward the electrophotographic photosensitive member is provided between the first frame member and the second frame member. 5. The developing device according to any one of 1 to 4. 6. The moving direction of the first frame is perpendicular to the direction of the acting force when the driving force is transmitted to the toner carrier, or the acting force or its reaction force is the first frame. 6. The developing device according to claim 1, wherein the developing device is in a direction in which the body is pressed toward the electrophotographic photosensitive member. 7. A process cartridge comprising an electrophotographic photosensitive member carrying a latent image, and the developing device according to claim 1 for developing the latent image. 8. An electrophotographic photosensitive member carrying a latent image, a developing device according to claim 1 for developing the latent image, and a carrying unit for carrying a recording medium. A characteristic image forming apparatus.