JPH10133472A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which maintains the distance between a photoreceptor and a developing roller highly accurately. SOLUTION: In the image forming device having a developing device which can be attached/detached to/from the main body of the image forming device, the developing device is divided into a developing roller part 20 having the developing roller 21 for rendering an electrostatic latent image on the surface of the photoreceptor 10 visible, and a developing tank part 30 having a paddle 31 for stirring and carrying developer. The shafts 212b and 231 of the developing roller 21 are supported by first side plates 60a and 60b supporting the photoreceptor 10, the developing roller part 20 is also supported by the first side plates 60a and 60b, and the developing tank part 30 are supported by second side plates 70a and 70b which are independent of the first side plates 60a and 60b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus to which an electrophotographic system such as an electrostatic copying machine, a printer, a facsimile and the like is applied. The present invention relates to an image forming apparatus having the apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile apparatus using an electrophotographic process, a developing device supplies toner from an electrostatic latent image formed on a photosensitive member. The electrostatic latent image is visualized, and the visible image is transferred and fixed on recording paper to form an image.

As a developing method using a developing device, a two-component developing method is predominant from the viewpoint of improving image quality. In this developing method, the distance between the photosensitive member and the developing roller, that is, the developing gap, The quality of the product was greatly affected, and great care was taken to control the development gap. In particular, it has been confirmed that the image quality can be improved by making the development gap as narrow as possible. From the demand for improving the image quality, it is required to make the development gap narrower than ever. Also, when the developing gap is narrowed,
The development gap must be managed with high precision.

Japanese Patent Laid-Open Publication No. Hei 5-323795 discloses a structure for supporting a developing roller for controlling the developing gap with high accuracy. According to this publication, the developing device
A developing tank having a developing roller, a paddle, a pair of first developing roller side plates respectively supporting both ends of the developing tank, and supporting both ends of the developing roller, respectively, and engaging with the first developing roller side plate; It mainly comprises a pair of second developing roller side plates. The developing device is supported on the main body side plate by supporting both ends of the shaft of the developing roller on a pair of main body side plates supporting the photoconductor. By supporting both ends of the shaft of the developing roller on the main body side plate, the developing gap between the photoconductor and the developing roller is maintained with high accuracy.

[0005]

However, in the developing roller support structure disclosed in the above-mentioned publication, the entire developing device, that is, both the developing roller and the developing tank are mounted on the main body side plate supporting the developing roller. Because of the support, the weight of the developing device is added to the main body side plate. For this reason, there is a possibility that deformation such as distortion or bending may occur on the main body side plate due to the weight of the developing device. However, there is a problem that the accuracy of the developing gap is reduced due to the deformation of the main body side plate.

In order to prevent deformation of the main body side plate,
Although it is conceivable to improve the rigidity of the main body side plate by drawing the main body side plate or increasing the thickness of the main body side plate, new problems such as an increase in cost and an increase in weight occur.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus capable of maintaining a high precision between a photosensitive member and a developing roller.

[0008]

According to the first aspect of the present invention,
In an image forming apparatus having a developing device detachable from a main body of the image forming apparatus, the developing device includes a developing roller unit having a developing roller for visualizing an electrostatic latent image on a surface of a photoreceptor; And a developing tank portion having a paddle for stirring and transporting the developer, a developing roller shaft is supported on a first side plate supporting a photoconductor, and a developing roller portion is supported on the first side plate. In this configuration, the tank is supported by a second side plate different from the first side plate.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the developing roller portion includes a blade for regulating a spike height, which is disposed at a predetermined distance from the developing roller, and each of the developing roller and the blade. This is a configuration having a pair of developing roller side plates that respectively connect both ends.

[0010] The third aspect of the present invention is the first or second aspect.
In the image forming apparatus described above, the developing tank unit has a paddle driving gear that rotationally drives the paddle, and the developing roller unit includes a roller driving gear that rotationally drives the developing roller, and a gear that meshes with the roller driving gear. The developing roller unit is swingably connected to the developing tank unit around the gear shaft in a state where the gear meshes with the paddle driving gear.

According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect, the gear is driven to drive the roller driving gear and the paddle driving gear.

According to a fifth aspect of the present invention, in the image forming apparatus of the fourth aspect, the drive input to the gear is a coupling input.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, an image forming apparatus suitable for carrying out the present invention will be described. In FIG. 1, reference numeral 10 denotes a photoconductor as an image carrier. Around the photoreceptor 10, a charge removing lamp 11 for erasing the charge remaining on the photoreceptor 10 and setting its surface potential to a reference potential, a charging charger 12 for charging the surface of the photoreceptor 11 to a certain potential, An exposure unit 13 for forming an electrostatic latent image on the photoreceptor 10 based on image information obtained by a reading unit (not shown); and a developing device 14 for attaching toner to the electrostatic latent image to visualize the image. A transfer unit 15 that transfers a visual image to transfer paper and conveys the transfer paper, and a cleaning device 16 that removes toner remaining on the photoconductor 10 after transfer and cleans the photoconductor 10 are arranged. . The transfer paper is sent to the vicinity of the transfer means 15 so that the leading end of the visible image on the photoconductor 10 and the leading end of the transfer paper coincide. A registration roller pair 17 is provided.

The photoreceptor 10, the charging charger 12, the cleaning device 16 and the like are integrally formed as a unit to form a unit, and these members form a photoreceptor unit. The photoconductor 10 is supported by side plates 60a and 60b (see FIG. 2) of the photoconductor unit as a first side plate. Side plates 60a, 60b of photoconductor unit
Are provided with a pair of positioning holes 61 and 62 for positioning and supporting a developing roller unit 30 described later. Positioning hole 61 provided in side plate 60a of photoconductor unit
Is provided with a bearing 63, and the side plate 60 of the photoreceptor unit is provided.
The positioning hole 62 provided in b is D-shaped.

The photoreceptor unit is supported by main body side plates 70a and 70b (see FIG. 2) of the image forming apparatus as a second side plate. The main body side plates 70a, 70b are provided with a pair of positioning support portions 71, 71, respectively, for positioning and supporting a developing tank portion 30 described later. The positioning support portions 71, 71 are attached to the main body side plates 70a, 70b by screws 72, and include a support holder 73 in which a later-described main reference pin 37 is fitted and a positioning hole 74 in which a later-described secondary reference pin 38 is fitted. It is configured.

The operation of the image forming apparatus will be briefly described.
First, the surface of the photoconductor 10 is charged to a certain potential by the charging charger 12. The image data is processed by the image processing unit, and the exposure unit 13 controls the photoconductor 1 according to the data.
0, an electrostatic latent image is formed on the surface. The electrostatic latent image on the photoreceptor 10 is made visible by attaching toner by the developing device 14. One transfer sheet is fed from a sheet feeding device (not shown), and the transfer sheet is sent to a pair of registration rollers 17. The registration roller pair 17 sends out the transfer paper at a timing such that the leading end of the visible image on the photoconductor 10 coincides with the leading end of the transfer paper. The transfer paper onto which the visible image has been transferred by the transfer means 15 is heated and fixed by a fixing device (not shown), and then is discharged to a discharge tray. The toner remaining on the photoreceptor 10 is removed by the cleaning device 16, while the potential remaining on the photoreceptor 10 is discharged by the discharge lamp 11 to prepare for the next image formation.

As shown in FIGS. 1 and 2, the developing device 14
It mainly comprises a developing roller section 20 for visualizing an electrostatic latent image on the surface of the photoconductor 10 and a developing tank section 30 for stirring the developer and transporting the developer to the developing roller section 20. I have. As shown in FIGS.
Is detachable from the developing tank unit 30. The structure for attaching and detaching the developing roller unit 20 to and from the developing tank unit 30 will be described later.

As shown in FIG. 3, the developing roller unit 20
A developing roller 21 for carrying the developer conveyed by the developing tank unit 30; a doctor blade 22 for regulating the height of the developer formed on the developing roller 21;
1 and a pair of developing roller side plates 23a and 23b connecting both ends of the doctor blade 22 respectively.

The developing roller 21 comprises a cylindrical developing sleeve 210 and a magnet roller 211 housed in the developing sleeve 210. One end 212a of the magnet roller shaft 212 slightly protrudes from one end surface of the magnet roller 211, and the other end 212b of the magnet roller shaft 212 is
11 protrudes longer than the one end 212a. A notch 212c is formed in a part of the peripheral surface of the other end 212b so as to have a substantially D-shaped cross section corresponding to the shape of the positioning hole 62. The other end 212b is fixed to the developing roller side plate 23b.

The developing sleeve 210 is rotatably supported by the magnet roller 211. Flanges 213 and 214 are fitted into both ends of the developing sleeve 210, respectively. A hole 213a into which one end 212a of the magnet roller shaft 212 is fitted is formed inside one flange 213, and a copper-based sintered bearing 213b is provided on the inner peripheral surface of the hole 213a. Outside the flange 213, a bearing 230 is attached to the developing roller side plate 23a.
A developing sleeve shaft 231 rotatably supported via the shaft is integrally formed. A roller drive gear 24 that rotationally drives the developing sleeve 210 is press-fitted and fixed to the developing sleeve shaft 231. A hole 214a through which the other end 212b of the magnet roller shaft 212 is inserted is provided at the center of the other flange 214, and a copper-based sintered bearing 214b is provided on the inner peripheral surface of the hole 214a.

In the vicinity of the developing sleeve 210, a doctor blade 22 is arranged at a predetermined distance from the developing sleeve 210. Both ends of the doctor blade 22 are fixed to the developing roller side plates 23a, 23b by screws 25, respectively. I have. By fixing both ends of the doctor blade 22 to the developing roller side plates 23a and 23b,
The developing roller side plates 23a and 23b are connected to each other.

On each end face of the developing roller side plates 23a, 23b, a projection 26 which engages with a later-described engaged portion 40, 40 is provided.
a and 26b are provided respectively. Projections 26a, 2
6b are provided at mutually symmetric positions. As shown in FIG. 4, the cross-sectional shapes of the protrusions 26a and 26b are both rectangular. Projection 26a of developing roller side plate 23a
A gear 27 meshing with the roller drive gear 24
Are rotatably supported via bearings 28. As shown in FIG. 5, a pair of claws 29 to which the driving force from the main body is transmitted is formed on the outer end surface of the gear 27. Claws 29
, A driving member 50 provided on the main body side is coupled and coupled. The end face of the driving member 50 that is connected to the gear 27 is formed with a recess in which the claw 29 is engaged.

As shown in FIG. 2, the developing tank unit 30
A paddle 31 for stirring and transporting the developer;
And a casing 32 for storing the.
On the outer peripheral surface of the paddle 31, a transport spiral 31a for transporting the developer from right to left in FIG. 2 is formed in a spiral shape. Inside the paddle 31, the developer is transported from left to right in FIG. (Not shown) is stored. The paddle 31 is attached to the bearing 32 with respect to the casing 32.
It is rotatably supported via. One end of the paddle 31 is provided with a paddle drive gear 34 for driving the paddle 31 to rotate, and the other end of the paddle 31 is supplied with a developer containing a two-component developer composed of toner and carrier. A part 35 is provided.

At a predetermined position of the casing 32, a concentration detecting sensor 3 for detecting the concentration of the developer in the developing tank 30 is provided.
6 are provided (see FIG. 1). As shown in FIGS. 4 and 5, both end plates 32a and 32b of the casing 32 have main reference pins 37 fitted into the support holders 73 of the main body side plates 70a and 70b, and positioning holes 74 of the main body side plates 70a and 70b.
, And a secondary reference pin 38 that fits into each other. Notches 39 with which the developing roller side plates 23a and 23b are respectively engaged are formed at upper end edges of both end plates 32a and 32b. In the vicinity of the notch 39 at the upper ends of the end plates 32a and 32b, engaged portions 40 with which the projections 26a and 26b are engaged are provided, respectively.

As shown in FIG. 6, the engaged portion 40 is provided with a hole 41 in which the projections 26a and 26b are rotatable, and a slit 42 continuous from the hole 41 is formed in the engaged portion. It is provided toward the upper end of 40. Hole 41
The gear 27 is provided at a position where the gear 27 meshes with the paddle drive gear 34 when the projections 26 a and 26 b engage with the engaged portion 40.

Next, the developing roller unit 20 and the developing tank unit 3
The connection with 0 will be described with reference to FIGS. The developing roller unit 20 is set up with respect to the developing tank unit 30, that is, in a state where the doctor blade 22 is located below the developing roller 21. While maintaining this state, as shown in FIG. 6, the projection 26 a is inserted into the slit 42 of the engaged portion 40 to engage with the hole 41, and the gear 27 is meshed with the paddle drive gear 34. After the projection 26a engages with the hole 41 and the gear 27 meshes with the paddle drive gear 34, the developing roller unit 20 is turned about 90 degrees in the direction of arrow A in FIGS. The developing roller side plate 23a is engaged with the notch 39 of the casing 32. In this manner, the developing roller unit 20 is attached to the developing tank unit 30, and the developing device 14 is assembled. In FIG. 6,
For convenience of explanation, the illustration of the gear 27 and the paddle drive gear 34 is omitted. Although the connecting operation has been described on one end side of the developing roller unit 20 and the developing tank unit 30, the same connecting operation is performed on the other end side of the developing roller unit 20 and the developing tank unit 30.

The attachment of the developing device 14 to the main body of the image forming apparatus will be described. First, after assembling the developing device 14, the shaft 212b of the magnet roller 211 is positioned in the positioning hole 62, and the shaft 231 of the developing sleeve 210 is positioned in the positioning hole 6.
1 respectively, the developing roller unit 20
Are positioned and supported on the side plates 60a and 60b of the photoconductor unit. Next, the main reference pin 37 is connected to the support holder 73.
By fitting the secondary reference pins 38 into the positioning holes 74, the developing tank unit 30 is moved to the main body side plate 70a,
It is positioned and supported with respect to 70b. Developing roller section 20
By supporting the developing tank portion 30 on different side plates, the mounting of the developing device 14 to the main body is completed, and after the mounting is completed, the driving member 50 of the main body is coupled to the gear 27 via the claw 29. You.

When the driving member 50 is driven to rotate, this driving force is transmitted to the roller driving gear 24 and the paddle driving gear 34 via the gear 27, and the developing sleeve 210 and the paddle 31 are rotated.

Since the developing roller unit 20 is positioned and supported by the side plates 60a and 60b of the photoconductor unit, the photoconductor 1
The position relative to 0 can be attached with high precision, and the development gap can be managed with high precision. On the other hand, the developing tank 3
Since 0 is positioned and supported by the main body side plates 70a and 70b, it is possible to prevent the weight of the developing tank unit 30 from being added to the side plates 60a and 60b of the photoconductor unit. Therefore, it is possible to prevent the side plates 60a and 60b of the photoconductor unit from being deformed, to maintain the developing gap with high accuracy, and to obtain a high quality image.

The developing roller unit 20 is swingably supported about the projections 26a and 26b, that is, the shaft of the gear 27, with respect to the developing tank unit 30, so that the shaft of the gear 27 and the roller driving gear 24 is rotated. The distance between them does not change. Therefore, the driving force from the main body is transmitted to the roller driving gear 24 via the gear 27.
Can be transmitted efficiently. In addition, since the driving force is also transmitted to the paddle driving gear 34 via the gear 27, the driving load on the developing roller and the paddle is reduced. Therefore, gear 2
7. The durability of the roller drive gear 24, paddle drive gear 34, bearings 28, 33, 230, etc. can be improved. Further, since the connection between the gear 27 and the driving member 50 is a coupling connection, the transmission of the driving force is performed efficiently.

After the developing device 14 is attached to the main body, the positional relationship between the developing roller portion 20 and the developing tank portion 30 in the developing device 14 may be slightly shifted. The agent is adsorbed on the magnet roller 211
Therefore, even if the positional relationship between the developing roller unit 20 and the developing tank unit 30 is misaligned, the suction of the developer is not affected.

Next, the operation of the developing device 14 will be briefly described. The developing device 14 controls the driving member 5 during the developing operation.
0 from the roller driving gear 24 via the gear 27.
The developing roller 21 and the paddle 31 are driven, and the developer in the developing tank unit 30 is stirred by the paddle 31 and transported. The developing sleeve 210 adsorbs and transports the developer conveyed from the paddle 31 by the magnetic force of a magnet roller 211 disposed therein. A part of the developer on the developing sleeve 210 is scraped off by the doctor blade 22, adjusted to a predetermined amount, and transported to a position facing the photoconductor 10 to develop the latent image on the photoconductor 10.

After the completion of the development, the developer is
After falling off the paddle 31, the paddle 31 is stirred again by the paddle 31 and transported. On the other hand, doctor blade 2
The developer scraped off in 2 is also dropped onto the paddle 31 and is again stirred and transported.

Another method of attaching the developing device 14 to the main body of the image forming apparatus will be described. First, the developing roller unit 2
0 is positioned and supported on the side plates 60a and 60b of the photoconductor unit. Thereafter, the developing roller unit 20 is moved to the developing tank unit 30.
And the developing tank portion 30 is positioned and supported on the main body side plates 70a and 70b. As described above, the developing roller unit 20 and the developing tank unit 30 are separately provided to the side plates 60a and 60b of the photosensitive unit and the main body side plate 70.
a and 70b may be positioned and supported. At this time, as described above, the developing tank unit 30 is connected to the main body side plate 7.
At the same time, the developing roller unit 20 and the developing tank unit 30 are connected to each other.

[0035]

As described above, according to the first aspect of the present invention, the developing device is divided at least into the developing roller section and the developing tank section, and the developing roller section supports the first photosensitive member. Since the developing tank is supported by the side plate and the developing tank portion is supported by the second side plate different from the first side plate, deformation such as distortion or bending of the first side plate due to the weight of the developing tank portion is prevented, The effect of the developing tank on the first side plate can be prevented. Therefore, the developing gap between the photosensitive member and the developing roller can be maintained with high accuracy. Further, it is not necessary to improve the rigidity such as drawing or increasing the thickness of the first side plate to prevent the deformation of the first side plate, and it is possible to prevent the problems of cost increase and weight increase.

According to the second aspect of the present invention, the developing roller section includes a pair of developing blades that are arranged at a predetermined distance from the developing roller, and that connects the respective ends of the developing roller and the blade. Since it has a roller side plate, the developing roller and the blade are integrally formed with each other, and it is possible to prevent a change in the interval between the developing roller and the blade,
The distance between the developing roller and the blade can be maintained with high accuracy.

According to the third aspect of the present invention, the developing roller is supported by the developing tank so as to be swingable about the gear shaft in a state where the gear meshes with the paddle drive gear. Even if the roller part swings, a change in the center distance between the gear and the roller driving gear can be prevented, and the driving force can be efficiently transmitted between the gear and the roller driving gear.

According to the fourth aspect of the present invention, since the gears are driven to drive the roller drive gear and the paddle drive gear, the driving load on the developing roller and the paddle is reduced, and the durability can be improved.

According to the fifth aspect of the present invention, since the drive input to the gear is a coupling input, the drive input to the gear is efficiently performed, and the durability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus suitable for carrying out the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partially broken plan view of a developing roller unit.

FIG. 4 is a diagram for explaining connection between a developing roller unit and a developing tank unit, and is an exploded perspective view of one end of a developing device.

FIG. 5 is a diagram for explaining connection between the developing roller unit and the developing tank unit, and is an exploded perspective view of the other end of the developing device.

FIG. 6 is a diagram for explaining an engagement operation of a projection with an engaged portion, and is an enlarged front view of the engaged portion.

FIG. 7 is a side view of the other end of the developing device for explaining a connecting operation between the developing roller unit and the developing tank unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photoconductor 14 Developing device 20 Developing roller part 21 Developing roller 22 Doctor blade 23a, 23b Developing roller side plate 24 Roller drive gear 26a, 26b Projection 27 Gear 29 Claw 30 Developing tank part 31 Paddle 32 Casing 34 Paddle drive gear 37 Main reference pin 38 Secondary reference pin 40 Engaged part 50 Drive member 60a, 60b Side plate 61, 62 Positioning hole 70a, 70b Main body side plate 71 Positioning support part

Claims (5)

[Claims] 1. An image forming apparatus having a developing device detachable from a main body of the image forming apparatus, wherein the developing device has a developing roller for visualizing an electrostatic latent image on a surface of a photoreceptor. Stir the developer and developer
A developing tank portion having a paddle to be conveyed; a first side plate supporting the photoconductor; a shaft of the developing roller supported; a developing roller portion supported by the first side plate; An image forming apparatus, wherein the developing tank portion is supported on a second side plate different from the first side plate. And a pair of developing roller side plates for connecting the both ends of the developing roller and the blade, wherein the developing roller portion is provided at a predetermined distance from the developing roller. The image forming apparatus according to claim 1, further comprising: 3. The developing tank section has a paddle driving gear for driving the paddle to rotate. The developing roller section has a roller driving gear for driving the developing roller to rotate, and a gear meshing with the roller driving gear. Wherein the gear is meshed with the paddle drive gear, and the developing roller unit is swingably connected to the developing tank unit around the axis of the gear. The image forming apparatus according to claim 1. 4. An image forming apparatus according to claim 3, wherein said gear is driven to drive said paddle drive gear and said roller drive gear. 5. The image forming apparatus according to claim 4, wherein the drive input to the gear is a coupling input.