JP2003035981A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which forms a good image stable the lapse of time by enhancing the strength of the drive output gear of a main body in the drive part of a rotary type developing device. SOLUTION: When a stepping motor 9 is driven and one development unit 11Y is rotated and moved toward a development position 3, an input gear 23 meshes with the output gear 22, a driving shaft 15Y transmits the rotation of a driving motor 26 through a sleeve gear 21 to rotate a developing sleeve 12Y, and a latent image formed on a photoreceptor 2 is developed. The output gear 22 of a drive unit and the input gear 23 with which the output gear 22 meshes have sharp tips of teeth in order to facilitate mesh. Accordingly, each of both gears is tempered using a metallic sintered material for enhancing durability, although it is disadvantageous for the strength of the tips of teeth.

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 having a rotary developing device.

[0002]

2. Description of the Related Art In an image forming apparatus having a rotary developing device such as a color copying machine, the drive means of the rotary developing device relates to a main body drive output gear and its input gear. To the inventors of the present application, there is no study for optimizing hardness and shape.

The present invention has been made in view of this point, and in the drive section of the rotary developing device, the strength of the main body drive output gear is increased to form an image capable of forming a stable and good image over time. An object is to provide a forming device.

It is another object of the present invention to provide an image forming apparatus capable of preventing wear of input / output gears and forming a good image in a driving portion of a rotary developing device.

[0005]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention is an image forming apparatus having a rotary developing device, wherein the rotary developing device is driven. Part, the tooth surface hardness of the main body drive output gear of the rotary developing device is set to be 30 or more harder in Vickers hardness than the tooth surface hardness of the input gear of the rotary developing device. To do.

According to a second aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to the first aspect, the tooth surface hardness of the input gear of the rotary developing device is a Vickers hardness. It is characterized by being set to 300 or more.

According to a third aspect of the present invention, in order to achieve the above object, there is provided an image forming apparatus having a rotary developing device, wherein a drive portion of the rotary developing device drives a main body of the rotary developing device. Among the output gear and the input gear of the rotary developing device, at least the shape of the tip of the input gear of the rotary developing device is sharpened so as to easily enter between the tips of the main body drive output gear, and the main body drive output It is characterized in that the tooth surface hardness of the gear is made harder than the tooth surface hardness of the input gear of the rotary developing device.

According to a fourth aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to the third aspect, the tooth surface hardness of the main body drive output gear of the rotary developing device is changed to the rotary developing device. It is characterized in that it is harder than the tooth surface hardness of the input gear of the apparatus by 30 or more in Vickers hardness.

According to a fifth aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to the fourth aspect, the tooth surface hardness of the input gear of the rotary developing device is a Vickers hardness. It is characterized by becoming 300 or more

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a main part of an image forming apparatus having a rotary developing device. In the figure, 1 is a developing device and 2 is a photoconductor. The developing device 1 includes a yellow developing unit 11Y for developing an electrostatic latent image on the photoreceptor 2 into a yellow toner image, a cyan toner image, a magenta toner image, and an image black toner image, as shown in the drawing, and a cyan developing unit 11Y. Developing unit 11C, magenta developing unit 11
The developing unit 11K for M and black is provided.

These developing units 11Y, 11M, 11
C and 11K are rotationally moved toward the developing position 3 facing the photoconductor 2 by the revolver rotation driving unit shown in FIG. Further, the developing units 11Y, 11M, 11C, 11K
Is a well-known developing sleeve 12Y, 12 as a developer carrying member that rotates by bringing the brush of the developer into contact with the surface of the photoconductor in order to visualize the electrostatic latent image formed on the photoconductor 2.
M, 12C, 12K and the developer in each developing unit are pumped up and supplied to each developing sleeve while stirring 2
Book transport screws 13Y, 13M, 13C, 13K
And doctor blades 14Y, 14M, 14 for making the height of the developing brush formed by each developing sleeve constant.
It is equipped with C and 14K.

Each developing sleeve has a drive shaft 15Y, 15
It is provided so as to be integrally rotatable with M, 15C and 15K.
In the present embodiment, the developing device 1 has a home position when the developing unit 11K is in the developing position as shown in FIG. Further, as shown in FIG.
Are rotatably supported by bearings 6 and 7 mounted on the front and rear side plates 4 and 5, respectively, so that each developing unit can be moved to the developing position 3. A ring gear 8 is mounted on the rear plate 4 of the revolver. The ring gear 8 meshes with a drive gear 10 that is rotated by a stepping motor 9 that serves as a drive source for the revolver rotation drive unit.

Then, each developing unit sequentially rotates and moves toward the developing position 3 when the stepping motor 9 is driven, and the electrostatic latent image formed corresponding to the color image on the photoconductor 2 is made to correspond to the electrostatic latent image. Develop with color toner.

The structure of the driving device of the developing device 1 will be described. The driving device rotates the developing sleeves by transmitting the driving force to the developing sleeves 12Y, 12M, 12C and 12K of the developing units shown in FIG.

FIG. 3 is a plan view showing a state where the driving device of the developing device 1 drives the developing unit 11Y having yellow toner. Since the developing units have the same configuration except for the color of toner, only the developing unit 11Y having yellow toner will be described with reference to FIG. 3, and the configurations relating to the remaining units will be omitted.

On the drive shaft 15Y of the developing sleeve 12Y,
A sleeve gear 21 that constantly meshes with the relay gear 20 is mounted so as to rotate integrally with the drive shaft 15Y. In the present embodiment, the drive output unit 24 is a portion where the output gear 22 and the input gear 23 mesh with each other. As described above, the gear train having the input gear 23 as the first stage and the sleeve gear 21 as the final stage is also provided in another developing unit.

The drive means 25 shown in FIG. 3 has a drive pulley 27 which is directly connected to a drive motor 26 as a drive source, a driven pulley 29 which is fixed to an end of a support shaft 28, and a pulley which is wound between both pulleys. The connecting belt 30 is provided. Support shaft 2
The reference numeral 8 is rotatably supported by being inserted into slide bearings 33, 33 on a frame 31 of the apparatus and a bracket 32 having a U-shaped cross section which is fastened to the frame 31 with screws. The support shaft 28 is arranged so that its rotation center line O1 is parallel to the rotation center line O2 of the shaft 38 of the input gear 23.

At the center of the support shaft 28 located in the bracket 32, a relay gear 34 is mounted so as to rotate integrally with the support shaft 28. A clutch gear 35 mounted on a drive transmission shaft 37 meshes with the relay gear 34. The relay gear 34 and the clutch gear 35 constitute a drive input section for transmitting the drive force from the drive means 25 to the drive transmission shaft 37.

The clutch gear 35 is under the control of a clutch 36 which connects and disconnects the driving force from the drive means 25 to the drive transmission shaft 37. An electromagnetic clutch is used as the clutch 36, and when the developing sleeve 12Y is rotated, its operation is controlled by a control unit (not shown). The clutch gear 35 serves to drive the drive transmission shaft 3 when the clutch 36 operates.
When the clutch 36 rotates integrally with the clutch 7 and the operation of the clutch 36 stops, the rotation of the clutch 36 is controlled by the clutch 36 so as to idle with respect to the drive transmission shaft 37.

The drive device is a drive transmission shaft 37 rotated by the drive means 25 shown in FIG. 3, and an input gear 2 provided at one end of the drive transmission shaft 37 and provided in each developing unit.
3 is meshed with the output gear 22 that meshes with each other in the vicinity of the developing position 3 to rotate each developing sleeve, so that the rotational drive force from the drive transmission shaft 37 can be transmitted.

According to the driving device having such a structure, as shown in FIG.
When one of the developing units, for example, the developing unit 11Y as shown in FIG. 3, rotates toward the developing position 3 by driving the stepping motor 9 shown in FIG. 3, the input gear 23 meshes with the output gear 22. When the drive motor 26 is driven and the clutch 36 is in the operating state, the drive motor 26
Is transmitted to the drive shaft 15Y via the sleeve gear 21 to rotate the developing sleeve 12Y, and the latent image formed on the photoconductor 2 is developed.

FIG. 4 is a sectional view showing a state in which the input gear 23 meshes with the output gear 22. As shown, the output gear 22
The input gear 23 that meshes with has sharpened tips in order to facilitate meshing. For this reason, it is disadvantageous in terms of the strength of the addendum. Therefore, a sintered metal material is used, and both gears are quenched to improve durability. Due to the structure of the machine, which is a rotary developing device, the operating state is output gear 2
Since the ratio of 2 to 4 is 1 for the input gear 23, both gears 22 and 23 are likely to have different degrees of wear. Therefore, when the hardnesses of the two gears 22 and 23 are the same, the output gear 22 is quickly worn, and a gear pitch-like abnormal image is generated over time.

Therefore, in the present invention, a hardness difference is provided between the output gear 22 and the input gear 23, and the output gear 22 is set to the input gear 23.
Further, the Vickers hardness is set to 30 or more, and the input gear 23 is set to 300 or more in Vickers hardness. This balances the wear of both gears 22 and 23 and reduces the wear itself, so that stable mechanical quality can be maintained over time.

[0024]

As described above, the image forming apparatus according to the first aspect, the third aspect, and the fourth aspect of the present invention can increase the strength of the main body drive output gear that is frequently operated in the drive unit of the rotary developing device. There is an effect that the wear balance of the input and output gears can be balanced, one of them can be prevented from being rapidly worn, and a good image that is stable over time can be formed.

As described above, in the image forming apparatus according to the second and fifth aspects, in the drive portion of the rotary developing device, the gear is hardened to prevent wear and form a good image. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an image forming apparatus having a rotary developing device.

FIG. 2 is a perspective view showing a driving device of the rotary developing device of FIG.

FIG. 3 is a plan view showing a state in which a driving device of the developing device of FIG. 2 drives a developing unit having yellow toner.

FIG. 4 is a cross-sectional view of a state where the input gear shown in FIG. 3 meshes with the output gear.

[Explanation of symbols]

1 Development device 2 photoconductor 3 Development position 4, 5 revolver front and rear side plates 6, 7 bearing 8 ring gears 9 Stepping motor 10 drive gear 11Y, 11C, 11M, 11K Development unit 12Y, 12M, 12C, 12K Development sleeve 13Y, 13M, 13C, 13K Transport screw 14Y, 14M, 14C, 14K Doctor blade 15Y, 15M, 15C, 15K drive shaft 20 relay gears 21 sleeve gear 22 Output gear 23 input gear 24 Drive output section 25 Drive means 26 Drive motor 27 Drive pulley 28 spindles 29 Driven pulley 30 connecting belt 31 frames 32 bracket 33 plain bearings 34 relay gears 35 clutch gear 36 clutch 37 Drive transmission shaft 38 Input gear shaft O1 spindle rotation center line O2 input gear shaft axis of rotation

Claims (5)

[Claims] 1. An image forming apparatus having a rotary developing device, wherein in a drive portion of the rotary developing device, a surface hardness of a tooth portion of a main body drive output gear of the rotary developing device is controlled by Due to the hardness of the tooth surface of the input gear,
An image forming apparatus having a hardness of 30 or more. 2. The image forming apparatus according to claim 1, wherein the surface hardness of the tooth portion of the input gear of the rotary developing device is
An image forming apparatus having a hardness of 300 or more. 3. An image forming apparatus having a rotary developing device, wherein at least one of a main body drive output gear of the rotary developing device and an input gear of the rotary developing device is provided in a drive portion of the rotary developing device. The tip shape of the input gear of the rotary developing device is sharpened so as to easily fit between the tips of the main body driving output gear, and the surface hardness of the tooth portion of the main body driving output gear is set to the input of the rotary developing apparatus. An image forming apparatus characterized in that the tooth surface of the gear is harder than the surface hardness. 4. The image forming apparatus according to claim 3, wherein the surface hardness of the tooth portion of the main body drive output gear of the rotary developing device is
An image forming apparatus having a Vickers hardness of 30 or more higher than a tooth surface hardness of an input gear of the rotary developing device. 5. The image forming apparatus according to claim 4, wherein the tooth surface hardness of the input gear of the rotary developing device is
An image forming apparatus having a hardness of 300 or more.