JPH03140989A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent resonant from occurring by providing a damping device for damping the vibration of an image carrier at the time of rotating. CONSTITUTION:A photosensitive drum 2 functioning as the image carrier is rotatably provided in a main body 1 and an electrostatic charger 3, an exposing part 4, a developing device 5, transfer and separation chargers 6 and 7, a cleaning device 8, and a static eliminator 9 are disposed on the periphery part of the drum 2. A driving gear 31 is attached to one end of the drum 2 and a flange 32 is attached to the other end side. Then, chloroprene rubber 33 as the damping means is stuck to the inner surface part of the flange 32 so that torsional vibration energy of the drum 2 at the time of rotating is made scattered and lost to lower a signal level. Thus, the resonant is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus used as, for example, an electronic copying machine.

(Prior Art) An electronic copying machine forms an electrostatic latent image corresponding to a document image on a freely rotatable photosensitive drum (image carrier), and develops the electrostatic latent image by supplying developer to this electrostatic latent image using a developing device. After this developer image is transferred to paper, the developer remaining on the photosensitive drum is scraped off by a cleaning blade (cleaning member) of a cleaning device.

Incidentally, the photosensitive drum is rotated by receiving a driving force from one end thereof, and at this time, torsional vibration in the direction of rotation having a high natural frequency is generated.

Furthermore, when cleaning the photosensitive drum, vibrations occur due to friction between the photosensitive drum and the cleaning blade.

(Problem to be Solved by the Invention) However, in the past, the frictional vibration between the photosensitive drum and the cleaning blade excites the torsional vibration of the photosensitive drum, and when a certain gain is exceeded, the torsional vibration of the photosensitive drum excites the torsional vibration of the photosensitive drum. Sound with the same frequency as the natural frequency (high frequency)
As a result, noise is generated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus that does not generate noise from an image carrier even if frictional vibrations between the image carrier and a cleaning member act on the image carrier. .

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention forms a developer image on a rotatably provided image carrier, and transfers this developer image to a transfer material. In the image forming apparatus, the developer remaining on the image carrier is scraped off by a cleaning member,
The present invention is characterized in that the image carrier is provided with an allocation means for damping vibrations during rotation of the image carrier.

(Function) The vibration damping means dissipates torsional vibration energy during rotation of the image carrier, lowers the vibration level, and prevents generation of resonance sound.

(Example) The present invention will be described below with reference to an example shown in the drawings.

FIG. 2 shows an electronic copying machine, and numeral 1 in the figure is the main body of the copying machine. A photosensitive drum 2 as an image carrier is rotatably provided in the copying machine main body 1, and a charger 3, an exposure section 4, a developing device are arranged around the photosensitive drum 2 sequentially along the direction of rotation. 5, a transfer/peel charger 6, 7, a cleaning device 8 having a cleaning blade (cleaning member), and a static eliminator 9 are provided.

Further, a conveyance path 10 is provided at the lower side of the copying machine main body 1, and this conveyance path 1o sequentially includes a paper feed roller 11, a registration roller 12, the transfer and peeling chargers along the conveyance direction of the paper P. 6.7, a conveyor belt 13, a fixing device 14, and a paper discharge roller 26 are provided.

Further, an exposure system 15 is provided on the upper side of the copying machine main body 1. This exposure system 15 includes an exposure lamp 16, a first
It is composed of third mirrors 17 to 19, a lens 20, and a fourth mirror 21. The exposure lamp 16 and the first mirror 17 are mounted on a first carriage (not shown), and the second and third mirrors 18 and 19 are mounted on a second carriage (not shown).
mounted on the carriage. The first and second carriages are provided movably along the document table 22,
The second carriage is moved in the same direction at half the speed of the first carriage.

Further, on one side of the copying machine main body 1, there is provided a paper feed force sensor) 2.
3 and 24 are removably attached, and a paper discharge tray 25 is provided on the other side.

Incidentally, a drive gear 31 is attached to one end of the photosensitive drum 2, as shown in FIG. A drive mechanism (not shown) is connected to this drive gear 31, and this drive mechanism rotates the drive gear 31 and rotates the photosensitive drum 2.
is designed to be rotationally driven.

Further, a flange 32 is provided on the other end side of the photosensitive drum 2.
is attached, and chloroprene rubber rubber (hereinafter referred to as CR rubber) 33 is stuck to the inner surface of this flange 32 as an allocation means.

The flange 32 is press-fitted into the photosensitive drum 2 and firmly attached, so that its vibration has no phase difference with the vibration of the photosensitive drum 2.

During image formation, the exposure lamp 16 irradiates light onto the original on the original platen 22, and the light reflected from the original is reflected from the original.
The third reflecting mirrors 17 to 19, and the lens 20
An image is formed on the surface of the photosensitive drum 2 via the fourth reflecting mirror 21. The surface of the photosensitive drum 2 is charged by a charger 3, and an electrostatic latent image of the original is formed thereon. This electrostatic latent image is sent to the developing device 5 by the rotation of the photosensitive drum 2.
Developing is performed by supplying toner from the developing device 5.

On the other hand, at this time, the paper P is taken out by the paper feed roller 1 from the paper feed cassette 23 or 24 and sent between the photosensitive drum 2 and the transfer charger 6 via the registration roller 2, and the image is transferred thereto. The paper P to which this image has been transferred is peeled off from the photosensitive drum 2 by the action of the peeling charger 7. Then, this peeled paper P is sent to the fixing device 14, where the image is fixed, and then the paper is discharged onto the paper discharge tray 25.

Furthermore, the toner t remaining on the photosensitive drum 2 after the image transfer to the paper P is scraped off and removed by the cleaning blade 8a of the cleaning device 8. Thereafter, the electric charge on the photosensitive drum 2 is removed by the static eliminator 9, and the photosensitive drum 2 is brought to a uniform potential in preparation for the next process.

By the way, when the photosensitive drum 2 rotates, torsional vibration in a mode having a certain natural frequency is generated in the photosensitive drum 2.

Further, at this time, frictional vibrations are generated due to friction between the cleaning blade 8a and the photosensitive drum 2.

This frictional vibration attempts to excite the natural frequency of the photosensitive drum 2. However, since the CR rubber 33 is attached to the flange 32 of the photosensitive drum 2 as described above,
Due to the internal loss of the CR rubber 33, the torsional vibration energy of the photosensitive drum 2 is dissipated, and the vibration level at the resonance point is suppressed.

Therefore, self-excited vibration of the photosensitive drum is regulated, and generation of resonance noise is prevented.

Note that FIG. 3(a) shows the frequency analysis results of the torsional vibration of the conventional photosensitive drum 2, and FIG. 3(b) shows the frequency analysis results of the torsional vibration of the photosensitive drum 2 of the present invention. The vibration level is lower than before.

Furthermore, the present invention is not limited to the above-mentioned example,
As shown in FIG. 4, a weight 42 made of sheet metal may be attached to the inner surface of the flange 32 with a double-sided tape 41.

The double-sided tape 41 itself has internal loss, and the weight 42 vibrates with a phase difference from the photosensitive drum 2. This cancels out the vibration of the photosensitive drum 2 itself and prevents self-excited vibration.

Further, as shown in FIG. 5, foamed CR rubber (hardness 150) is attached to the inner surface of the flange 32 by screws 51 with washers.
52 may be attached.

In this case, the basic operation is the same as in the first embodiment, but by adjusting the tightening torque of the washer-equipped screw 51, the frequency range in which the damping effect is exerted can be tuned.

Note that the damping means may be any member as long as it can provide appropriate positive damping to the vibration system.

Typical damping materials include butyl and NBR.

There are anti-vibration rubbers such as, but the present invention can also be effective with materials that have a certain degree of internal loss, such as CR rubber, foamed CR rubber, and ordinary double-sided tape.

[Effects of the Invention] As described above, according to the present invention, it is possible to control the self-excited vibration of the image carrier, prevent the generation of resonance sound, and reduce noise.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is an exploded perspective view of a photosensitive drum, Fig. 2 is a schematic configuration diagram showing an electronic copying machine, and Fig. 3 shows the vibration level of the photosensitive drum. FIG. 4 is a perspective view showing a first alternative embodiment of the present invention, and FIG. 5 is a perspective view showing a second alternative embodiment of the present invention. 2... Image carrier (photosensitive drum), 8a... Cleaning blade (cleaning member), P... Paper (transferring material)
33.52... CR rubber (vibration damping means) 41... Double-sided tape (vibration damping means), 42... Weight (distribution means), 5
1...Screw with washer (vibration damping means).

Claims (1)

[Claims] Image formation in which a developer image is formed on a rotatably provided image carrier, the developer image is transferred to a transfer material, and then the developer remaining on the image carrier is scraped off with a cleaning member. An image forming apparatus characterized in that the image bearing member is provided with a vibration damping means for damping vibrations during rotation of the image bearing member.