JP4745561B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus driven by a motor.
[0002]
[Prior art]
A conventional technique will be described with reference to the drawings.
[0003]
4 is an overall configuration diagram of a conventional image forming apparatus, FIG. 5 is an explanatory diagram of the periphery of a conventional motor, FIG. 6 is an explanatory diagram of a relationship between a motor gear and a developing rotary gear, and in particular, (a) is a motor. (B) is an explanatory view when the motor is stopped.
[0004]
As shown in FIGS. 4 and 5, in an electrophotographic color image forming apparatus for forming a full-color image, the developing rotary 123 rotates every rotation of the intermediate transfer body 109 during the color image formation, and the yellow developing device 120Y, The magenta developing device 120M, the cyan developing device 120C, and then the black developing device 121K are developed in the order of toner of each color as a developer. The developing rotary 123 is rotated around the rotating shaft 122 by the single-axis motor 101, and the developing devices for the respective colors are sequentially moved to positions facing the photosensitive drum 115. The developing rotary 123 is interlocked with the single-axis motor 101 via the developing rotary gear 106 and the motor gear 105.
[0005]
Since the intermediate transfer member 109 receives the toner image on the photosensitive drum 115 visualized by each developing device during the color image forming operation four times (each image of four colors of Y, M, C, and K), The intermediate transfer body 109 that rotates clockwise in the figure in synchronization with the outer peripheral speed of the photosensitive drum 115 and has undergone multiple transfer is transferred by swallowing and transferring the transfer material with the transfer roller 110 to which voltage is applied. The toner images of the respective colors on the intermediate transfer body 109 are simultaneously transferred onto the material.
[0006]
A pulse motor is generally used for driving the developing rotary 123 because rotation accuracy is required. Further, the pulse motor repeatedly starts up and stops repeatedly for switching the developing rotary 123. In order to prevent noise, step-out, and the like due to vibration during the operation, a damper 104, which is an elastic body, is sandwiched between the single-shaft motor 101 and the motor support plate 103 as shown in FIG.
[0007]
[Problems to be solved by the invention]
However, the image forming apparatus is required to rotate the developing rotary 123 at a higher speed as the image quality and speed are increased in recent years. This speeding up necessitates an increase in the size of the motor. The increase in motor torque overlaps with rapid start-up and stop, and when the single-axis motor 101 is operated as shown in FIG. 6, a high load is applied in different directions at the time of motor start-up and stop. When a high load is applied to the gear portion, as shown in FIG. 5, the motor itself via the damper causes rotation, expansion / contraction, and shaft collapse as shown in FIG.
[0008]
Moreover, the shaft collapse is further promoted by the weight of the motor. Due to this tilting of the shaft, the gears are not properly meshed with each other, not only the efficiency of drive transmission is deteriorated but also the cause of motor step-out. In order to suppress the deformation of these dampers themselves, the characteristics and shape of the damper 104 are changed to minimize this phenomenon, but since the damper 104 is an elastic body, this deformation cannot be completely removed. However, this deformation is promoted as the motor load increases. Although the motor shaft can be allowed to deform in the radial and thrust directions, the motor shaft collapse is fatal because it directly leads to motor step-out.
[0009]
Accordingly, an object of the present invention is to prevent vibration, step-out, and noise of the motor by eliminating shaft tilt of the motor and suppressing deformation of the damper.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a typical configuration of the present invention includes an image carrier, developing means for supplying a developer to the latent image formed on the image carrier and developing the image carrier, and the development. An image forming apparatus having a driving gear that rotationally drives the means, and a support plate that fixedly supports a side surface on one end side of the driving means through a damper member made of an elastic body, and the support An image forming apparatus comprising: a bearing that rotatably supports the other end side of the driving unit provided on the opposite side of the developing unit across a plate .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment)
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of the image forming apparatus, and FIG. 2 is an explanatory diagram of the periphery of the motor.
[0012]
(Image forming device)
As shown in FIG. 1, an image forming apparatus 1 forms an electrostatic latent image on an image carrier made of a photoconductor, and develops the latent image and transfers it to a sheet to form a full color image. The color image forming apparatus.
[0013]
The upper part of the apparatus main body 1 has an image reading unit for reading an image on the document S, and the document S placed on the document table glass 30 is exposed and scanned by the exposure lamp 31 to reflect from the document S. The light image is condensed on the full color sensor 14 via the mirrors 12a, 12b, 12c and the lens 13 to obtain a color separation image signal. The color-separated image signal is processed by a video processing unit through an amplifier circuit (not shown) and sent to an image forming unit.
[0014]
When an image formation start signal is input to the image forming unit, first, the photosensitive drum 15 as an image carrier is rotationally driven counterclockwise in the drawing by a driving unit (not shown). Around the photosensitive drum 15, a roller charger 17 for uniformly charging the photosensitive drum 15, a laser exposure optical system 18 as an exposure unit for forming a latent image on the photosensitive drum 15, and developing the latent image A fixed black developing device 21K, three rotatable color developing devices 20Y, 20M, and 20C, a cleaning unit 16, and an intermediate transfer member 9 are disposed.
[0015]
In the laser exposure optical system 18, the image signal from the image reading unit is converted into an optical signal by a laser output unit (not shown), and the converted laser beam is reflected by the rotary polygon mirror 18a and passes through the lens 18b and the mirror 18c. And projected onto the cylindrical surface of the photosensitive drum 15. At the time of image formation, the photosensitive drum 15 is rotated counterclockwise in the figure, and the photosensitive drum 15 is uniformly charged by the roller charger 17, and an optical image is irradiated for each separated color to form an electrostatic latent image. To do.
[0016]
The three rotating color developing devices 20Y, 20M, and 20C are detachably held by a developing rotary 23 as developing means that rotates about a rotation shaft 22, and each developing device is attached to the developing rotary 23 for image formation. While being held, it is rotated around the rotation shaft 22 so that the predetermined developing device stops at a position facing the photosensitive drum 15 and the developing sleeve faces the photosensitive drum 15 with a minute interval. After the positioning, a visible image is formed (developed) corresponding to the electrostatic latent image on the photosensitive drum 15.
[0017]
At the time of color image formation, the developing rotary 23 rotates every rotation of the intermediate transfer member 9, and the developing process is performed in the order of the yellow developing device 20Y, the magenta developing device 20M, the cyan developing device 20C, and then the black developing device 21K.
[0018]
Since the intermediate transfer member 9 undergoes multiple transfer four times (each image of four colors Y, M, C, and K) on the photosensitive drum 15 visualized by each developing device during a color image forming operation, the intermediate transfer member 9 is photosensitive. The intermediate transfer body 9 that rotates in the clockwise direction in the figure in synchronization with the outer peripheral speed of the body drum 15 and has undergone multiple transfer squeezes and conveys the transfer material 11 with the transfer roller 10 to which a voltage is applied. Each color toner image on the intermediate transfer member is simultaneously transferred to the transfer material 11 and sent to a fixing device which is the next process.
[0019]
The transfer material 11 holding the toner image is conveyed by the fixing roller 26 and the pressure roller 27, and the toner is fixed to the transfer material 11 by applying heat and pressure at the same time. Thereafter, the transfer material 11 is discharged to the outside of the apparatus and loaded on the discharge tray 28.
[0020]
(Configuration of drive motor)
As shown in FIG. 2, the drive motor 2 as a driving means for driving the developing rotary 23 is fixed to the motor support plate 3, abuts on a motor gear 5 as a driving gear coaxial with the driving motor 2, and the developing rotary 23 A driving force is transmitted to the developing rotary 23 via the developing rotary gear 6 as a coaxial reduction gear. A damper 4 that is an elastic body is sandwiched between the drive motor 2 and the motor support plate 3.
[0021]
Here, in this embodiment, the drive motor 2 of the developing rotary 23 is a double-axis motor, and the shaft side opposite to the drive transmission side of the motor shaft is supported by the bearing 8, and the motor support plate 3 supports the motor shaft support plate. 7 to fix. As a result, the shaft of the drive motor 2 is not tilted, the shaft of the motor is not tilted while suppressing vibration and noise, and motor step-out can be prevented.
[0022]
(Other embodiments)
In the above-described embodiment, the drive motor 2 is a double-axis motor. However, the present invention is not limited to this, and as shown in FIG. 3, the drive motor 2 is a uniaxial motor and the shaft on the extension of the motor gear 5 is a bearing. The same effect can be obtained with the configuration supported by 8.
[0023]
In the above-described embodiment, a full-color copying machine has been described as an example of the image forming apparatus. However, the present invention is not limited to this, and any image forming apparatus having a drive motor in the image forming unit may be used. An image forming apparatus such as the above can also be used.
[0024]
In the embodiment described above, the drive motor 2 is used to drive the developing rotary 23, but the present invention is not limited to this, and a drive source other than the developing rotary 23 and similar effects can be obtained.
[0025]
【The invention's effect】
As described above, in the present invention, since the shaft of the driving unit is supported by the bearing on the opposite side of the developing unit with the driving unit interposed therebetween, the shaft of the motor is prevented from being tilted and the deformation of the damper is suppressed. Motor vibration, step-out, and noise can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an image forming apparatus.
FIG. 2 is an explanatory view around a motor.
FIG. 3 is an explanatory view of the periphery of a motor according to another embodiment.
FIG. 4 is an overall configuration diagram of a conventional image forming apparatus.
FIG. 5 is an explanatory view around a conventional motor.
FIG. 6 is an explanatory diagram of a relationship between a motor gear and a development rotary gear.
[Explanation of symbols]
S: Document 2 ... Drive motor 3 ... Motor support plate 4 ... Damper 5 ... Motor gear 6 ... Development rotary gear 7 ... Motor shaft support plate 8 ... Bearing 9 ... Intermediate transfer member
10 Transfer roller
11… Transfer material
12a ... mirror
12b ... mirror
12c Mirror
13… Lens
14… Full color sensor
15… Photoconductor drum
16… Cleaning means
17 Roller charger
18 ... Laser exposure optics
18a ... rotating polygon mirror
18b ... Lens
18c ... mirror
20C: Cyan developer
20M ... Magenta developer
20Y ... Yellow developer
21K Black developer
22… Rotating shaft
23… Development rotary
26… Fixing roller
27… Pressure roller
28… discharge tray
30 ... plate glass
31… Exposure lamp

Claims (1)

Image forming comprising: an image carrier; a developing means for supplying a developer to the latent image formed on the image carrier for development; and a driving means having a drive gear for rotating the developing means. In the device
A support plate for fixing and supporting a side surface on one end side of the drive means via a damper member made of an elastic body so as not to rotate, and the other end of the drive means provided on the opposite side of the development means across the support plate An image forming apparatus comprising: a bearing that rotatably supports the side .

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