JP2004037599A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of always forming a stable good image by increasing the strength of a main body drive output gear in a driving part for a rotary developing device. <P>SOLUTION: When a stepping motor 9 is driven and one developing unit 11Y is moved with rotation toward a developing position 3, an input gear 23 is engaged with an output gear 22, then, the rotation of a driving motor 26 is transmitted to a driving shaft 15Y through a sleeve gear 21, then, a developing sleeve 12Y is rotated so as to develop a latent image formed on a photoreceptor 2. As for the output gear 22 of the driving device and the input gear 23 engaged with the output gear 22, the tooth tips of them are sharpened so that the engagement is facilitated, and in order to increase the durability, they are respectively hardened by using metal sintering material. The hardness difference between the tooth parts of both gears 22 and 23 is made ≥300 and ≤600 as for Vickers hardness. The hardness specifying area is from the outside diameter surface of each gear 22 and 23 to the gear center or from the outside diameter surface to 2.5 modules. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus having a rotary developing device.
[0002]
Problems to be solved by the prior art and the invention
In an image forming apparatus having a rotary developing device such as a color copier, the present invention has been studied to optimize the hardness and shape of the main body drive output gear and its input gear in the driving means of the rotary developing device. Does not exist to the best of our knowledge.
[0003]
The present invention has been made in view of this point, and has an image forming apparatus capable of increasing the strength of a main body drive output gear in a driving unit of a rotary developing device and forming a stable and good image over time. The purpose is to provide.
[0004]
Another object of the present invention is to provide an image forming apparatus capable of preventing abrasion of an input / output gear and forming a good image in a driving section of a rotary developing device.
[0005]
Still another object of the present invention is to provide an image forming apparatus capable of preventing abrasion and improving secondary workability of a gear in a driving portion of a rotary developing device.
[0006]
[Means for Solving the Problems]
An image forming apparatus according to claim 1 of the present invention is an image forming apparatus having a rotary developing device, wherein a driving unit of the rotary developing device includes a main body of the rotary developing device. The tooth hardness of the drive output gear is made harder than the tooth hardness of the input gear of the rotary developing device, and the tooth hardness difference between the main body drive output gear and the input gear is set to 600 or less in Vickers hardness. It is characterized by the following.
[0007]
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 hardness designation areas of the main body drive output gear and the input gear are shifted from the outer diameter surface of these gears to the center of the gear. It is characterized by becoming up to.
[0008]
According to a third aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to the first aspect, the hardness designation areas of the main body drive output gear and the input gear are set at 2. It is characterized by having up to 5 modules.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating 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 photoreceptor. The developing device 1 includes a yellow developing unit 11Y for developing an electrostatic latent image on the photoconductor 2 into a yellow toner image, a cyan toner image, a magenta toner image, and an image black toner image, as shown in FIG. , A developing unit 11M for magenta, and a developing unit 11K for black.
[0010]
These developing units 11Y, 11M, 11C, and 11K are rotated by a revolver rotation drive unit shown in FIG. 2 toward a developing position 3 facing the photoconductor 2. The developing units 11Y, 11M, 11C, and 11K are provided with a developer carrier that rotates by contacting the ears of the developer with the surface of the photoconductor in order to visualize the electrostatic latent image formed on the photoconductor 2. A well-known developing sleeve 12Y, 12M, 12C, 12K as a body, and two conveying screws 13Y, 13M, 13C, 13K for pumping up and agitating the developer in each developing unit and supplying it to each developing sleeve while stirring. And doctor blades 14Y, 14M, 14C and 14K for keeping the height of the developing brush formed by each developing sleeve constant.
[0011]
Each developing sleeve is provided so as to be integrally rotatable with the drive shafts 15Y, 15M, 15C, and 15K. In the present embodiment, the home position of the developing device 1 is such that the developing unit 11K is at the developing position as shown in FIG. As shown in FIG. 2, the developing device 1 is 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 side plate 4 of the revolver. A drive gear 10 rotated by a stepping motor 9 serving as a drive source of a revolver rotation drive unit meshes with the ring gear 8.
[0012]
Each developing unit sequentially rotates and moves toward the developing position 3 when the stepping motor 9 is driven, and transfers the electrostatic latent image formed on the photosensitive member 2 corresponding to the color image to the corresponding color toner. And develop.
[0013]
The configuration of the driving device of the developing device 1 will be described. The driving device transmits a driving force to the developing sleeves 12Y, 12M, 12C, and 12K of the respective developing units shown in FIG. 1 to rotate the respective developing sleeves.
[0014]
FIG. 3 is a plan view showing a state where the driving device of the developing device 1 drives the developing unit 11Y having the yellow toner. Since the configuration of each developing unit is the same except for the color of the toner, only the developing unit 11Y having the yellow toner will be described with reference to FIG. 3, and the configuration of the remaining units will be omitted.
[0015]
A sleeve gear 21 that constantly meshes with the relay gear 20 is mounted on the drive shaft 15Y of the developing sleeve 12Y so as to be integrally rotatable with the drive shaft 15Y. In the present embodiment, a portion where the output gear 22 and the input gear 23 mesh with each other is defined as a drive output section 24. As described above, the gear train having the input gear 23 as the first stage and the sleeve gear 21 as the last stage is also provided in another developing unit.
[0016]
The drive means 25 shown in FIG. 3 includes a drive pulley 27 directly connected to a drive motor 26 as a drive source, a driven pulley 29 fixed to an end of a support shaft 28, and a connection bridged between the two pulleys. The belt 30 is provided. The support shaft 28 is rotatably supported by being inserted into sliding bearings 33, 33 in a frame 31 of the device and a bracket 32 having a U-shaped cross section fastened to the frame 31 with screws. The support shaft 28 is disposed such that its rotation center line O1 is parallel to the rotation center line O2 of the shaft 38 of the input gear 23.
[0017]
At the center of the support shaft 28 located inside the bracket 32, a relay gear 34 is mounted so as to be able 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 unit for transmitting the drive force from the drive means 25 to the drive transmission shaft 37.
[0018]
The clutch gear 35 is under the control of a clutch 36 that disconnects the driving force from the driving means 25 to the driving transmission shaft 37. An electromagnetic clutch is used as the clutch 36, and when the developing sleeve 12Y is rotated, the operation thereof is controlled by control means (not shown). The rotation of the clutch gear 35 is controlled by the clutch 36 so that the clutch gear 35 rotates integrally with the drive transmission shaft 37 when the clutch 36 operates, and idles with respect to the drive transmission shaft 37 when the operation of the clutch 36 stops.
[0019]
The drive unit is provided at one end of the drive transmission shaft 37, which is rotated by the drive means 25 shown in FIG. The transmission of the rotational driving force from the drive transmission shaft 37 is enabled by meshing with the output gear 22 that rotates the developing sleeve.
[0020]
According to the driving device having such a configuration, when the stepping motor 9 shown in FIG. 2 is driven to rotate one of the developing units, for example, the developing unit 11Y toward the developing position 3 as shown in FIG. The gear 23 meshes with the output gear 22. When the drive motor 26 is driven to operate the clutch 36, the rotation of the drive motor 26 is transmitted to the drive shaft 15Y via the sleeve gear 21 to rotate the developing sleeve 12Y, thereby forming the photosensitive member 2. The latent image is developed.
[0021]
FIG. 4 is a sectional view showing a state where the input gear 23 meshes with the output gear 22. As shown in the figure, the input gear 23 meshing with the output gear 22 has a pointed tip to facilitate the meshing. For this reason, it is disadvantageous in terms of the tooth tip strength. Therefore, a sintered metal material is used, and both gears are quenched to increase durability. In FIG. 4, the quenched portions are indicated by oblique lines. In the operating state, the ratio of the output gear 22 to the input gear 23 is 1 and the input gear 23 is 1 in the operating state due to the configuration of the machine that is a rotary developing device. . Therefore, if the hardness of the two gears 22 and 23 is the same, the output gear 22 will wear out quickly, and a gear pitch-shaped abnormal image will be generated over time.
[0022]
For this reason, a hardness difference is provided between the output gear 22 and the input gear 23, the output gear 22 is set to be 300 or more Vickers harder than the input gear 23, and the maximum hardness difference between the two gears 22, 23 is reduced. 600 or less. As a result, the wear itself due to the engagement of the two gears 22 and 23 is reduced, the wear balance is maintained, and stable mechanical quality can be maintained over time. If the hardening of the gears 22 and 23 is performed over the entire area of the gears, the quality can be maintained without wear over time. Also, by defining the quenched area from the tooth tips of the two gears 22 and 23 to be 2.5 times the module m, quenching is not performed in a range other than the tooth form of the gear requiring wear resistance. Secondary processing is easy, and the accuracy of the shape of the mounting portion (hole diameter, D-shape like shaft hole 23a of input gear 23, parallel pin fitting shape like shaft hole 22a of output gear 22) is improved. The driving vibration of the gears 22 and 23 is reduced, and a good image can be formed.
[0023]
【The invention's effect】
As described above, in the image forming apparatus according to the first aspect, in the driving unit of the rotary developing device, the wear of the input and output gears can be balanced by increasing the strength of the main body driving output gear that is frequently operated. In addition, there is an effect that one can be prevented from being abruptly abraded and a stable and good image can be formed over time.
[0024]
In the image forming apparatus according to the second aspect, in addition to the same effects as the first aspect, in the driving portion of the rotary developing device, the gear is quenched to prevent abrasion with time and to form a good image. There is an effect that can be.
[0025]
In the image forming apparatus according to the third aspect, in addition to the same effects as those of the first aspect, in the drive unit of the rotary developing device, wear is prevented by defining the hardened area of the input and output gears, The secondary workability of the gear is improved, the assembling accuracy of the gear can be improved, and the vibration of the gear can be reduced, so that a good image can be formed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating 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 showing a state where the input gear shown in FIG. 3 meshes with the output gear.
[Explanation of symbols]
Reference Signs List 1 developing device 2 photoreceptor 3 developing position 4, 5 revolver front and rear side plate 6, 7 bearing 8 ring gear 9 stepping motor 10 drive gear 11Y, 11C, 11M, 11K developing unit 12Y, 12M, 12C, 12K developing sleeve 13Y, 13M, 13C , 13K transfer screw
14Y, 14M, 14C, 14K Doctor blades 15Y, 15M, 15C, 15K Drive shaft 20 Relay gear 21 Sleeve gear 22 Output gear 23 Input gear 24 Drive output unit 25 Drive means 26 Drive motor 27 Drive pulley 28 Support shaft 29 Follower pulley 30 Connection belt 31 Frame 32 Bracket 33 Slide bearing 34 Relay gear 35 Clutch gear 36 Clutch 37 Drive transmission shaft 38 Input gear shaft O1 Support shaft rotation center line O2 Input gear shaft rotation center line

Claims (3)

An image forming apparatus having a rotary developing device, wherein in the driving section of the rotary developing device, the tooth hardness of the main body drive output gear of the rotary developing device is determined by the tooth hardness of the input gear of the rotary developing device. An image forming apparatus, wherein the difference in tooth hardness between the main body drive output gear and the input gear is set to be 600 or less in Vickers hardness. 2. The image forming apparatus according to claim 1, wherein the specified range of hardness of the main body drive output gear and the input gear is from the outer surface of the gear to the center of the gear. 2. The image forming apparatus according to claim 1, wherein the specified hardness range of the main body drive output gear and the input gear is set to 2.5 modules from the outer diameter surface of the gear.

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