JP3673735B2 - Cleaning device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning device that abuts a blade on the surface of an image carrier and removes toner adhering to the image carrier.
[0002]
[Prior art]
Conventionally, in an image forming apparatus such as a copying machine or a printer, an image is formed using a photosensitive drum as an image carrier as a means for forming a latent image. After the surface potential is applied by the primary charger and the latent image is formed by the writing optical system, the photosensitive drum is made visible by attaching toner as a developer to the latent image by the developing unit. It is transferred to the sheet material by the transfer means.
[0003]
At this time, the toner transferred to the sheet material by the transfer means is not 100%, and a small amount of toner remains on the surface of the photosensitive drum. Therefore, a cleaning device is used to clean and remove the residual toner from the surface of the photosensitive drum.
[0004]
As shown in FIG. 6, the residual toner removal structure is generally a method in which the edge portion 51 a of the elastic blade 51 is brought into contact with the surface of the photosensitive drum 50 and the residual toner on the surface of the photosensitive drum is scraped off. Used in many copying machines.
[0005]
Residual toner 52 scraped from the surface of the photosensitive drum is aggregated at the edge portion 51a of the blade 51 of the cleaning means that is in contact with the photosensitive drum 50. Normally, in the medium / low speed machine, the aggregated residual toner 52 falls into a container of the cleaning means with a certain size, so that there is no problem.
[0006]
However, the peripheral speed of the photosensitive drum has increased due to the recent increase in the speed of copying machines, and depending on the environmental conditions, the residual toner 52 aggregated on the edge portion 51a of the blade 51 continues to grow without falling, and then the edge of the blade A phenomenon may occur in which the nip portion of the portion 51a slips through. The residual toner that slips through is transferred to the sheet material in a streak form, resulting in an image defect.
[0007]
In order to prevent the occurrence of the image defect, the following conventional examples have been proposed.
[0008]
As a first conventional example, there is a method of applying vibration by a piezoelectric element to a blade as disclosed in JP-A-6-4014 and JP-A-11-174922 as means for improving the cleaning performance by the blade. As a second conventional example, there is a method of applying a collision vibration to the blade as disclosed in JP-A-9-160455. In recent years, as a third conventional example, a vibration motor has been proposed which is disposed on a frame provided on a blade portion of a cleaning means.
[0009]
[Problems to be solved by the invention]
However, the above-described conventional example has the following problems. First, in the case of the first conventional example, since the piezoelectric element is attached to the blade that deteriorates due to durability, it is difficult to increase the cost and to give sufficient vibration to remove the aggregated and grown residual toner. It was.
[0010]
In the case of the second conventional example, it is possible to give sufficient vibration to remove the aggregated and grown residual toner, but depending on the behavior of the blade when collision vibration is input, the residual toner slips through. The bad effects such as can be considered.
[0011]
In addition, in the case of the third conventional example, it is necessary to operate the vibration motor for a long time in order to obtain a good effect, and respond to today's needs such as a long life and low operating sound for long-time operation. It was not easy.
[0012]
The present invention solves the above-described conventional problems, and an object of the present invention is to provide a cleaning device that does not cause image defects over a long period of time by a small low-power motor.
[0013]
[Means for Solving the Problems]
Representative structure according to the present invention for achieving the above object, the mounting in the cleaning device for cleaning the image bearing member, an elastic blade to remove residual toner by contact with the image bearing member, an output shaft section A motor for generating vibration by rotating a weight, and a frame for holding the elastic blade and the motor and transmitting the vibration generated by the motor to the elastic blade, and causes the elastic blade to vibrate In some cases, the motor is intermittently repeatedly driven .
[0014]
In the above configuration, since the vibration is applied to the elastic blade by the motor drive, it is possible to remove the clumps of residual toner efficiently generated without quality image with high image formation failure is possible.
[0015]
Moreover, since it can be achieved with a small low-power motor, it is possible to simultaneously reduce power consumption and operating noise.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, an image forming apparatus including a cleaning device according to an embodiment of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a schematic explanatory view of an image forming apparatus, and FIG. 2 is a cross-sectional explanatory view of a cleaning apparatus.
[0018]
(Image forming device)
First, a schematic configuration of the image forming apparatus will be described with reference to FIG. The image forming apparatus shown in FIG. 1 has an image reading unit B above the recording unit A, and a document feeding device C can be mounted on the image reading unit B. The images are fed one by one and read by the image reading unit B. The information read by the image reading unit B is converted into a digital signal and sent to the recording unit A, and an image is recorded on the transfer material S based on the read information.
[0019]
The recording unit A of the present embodiment performs recording by electrophotography, and the transfer material S stored in the cassette 1 is conveyed to the image forming unit by the feeding roller 2 and the conveying roller 3. The image forming unit is rotatably provided with a photosensitive drum 4 as an image carrier. A primary charger 5 that uniformly charges the photosensitive drum around the photosensitive drum 4 and a photosensitive drum according to the digital signal. An exposure unit 6 that forms a latent image by exposure, a developing unit 7 that develops the latent image with toner, a transfer unit 8 that transfers the toner image to the transferred transfer material S, and a photosensitive material after transfer of the toner image to the transfer material S. A cleaning device 9 for removing the toner remaining on the body drum 4 is disposed, and the toner image is transferred onto a transfer material by a known electrophotographic method.
[0020]
Then, the transfer material S onto which the toner image has been transferred is transported to the fixing unit 11 by the transport belt 10 and heated and fixed, and then discharged to the outside by the discharge roller 12.
[0021]
(Cleaning device)
Next, the configuration of the cleaning device 9 that is a feature of the present invention will be described. As shown in FIG. 2, the cleaning device 9 includes a frame 20, a frame 21, a blade member 22, a magnet roller 23, a conveying screw 24, a squeeze sheet 25, a blade holder 26, a shaft 27, a shaft 28, a tension spring 29, and a plurality of tension springs 29. The motor unit 30 is configured.
[0022]
The blade member 22 is an elastic body and is held between the frame 20 and the blade holder 26 so that the edge portion is in contact with the photosensitive drum 4.
[0023]
A plurality of motor units 30 are also held by the frame 20. The frame 20 is swingably attached to the frame 21 via a shaft 27, the frame 20 is urged by a tension spring 29, and the blade member 22 is brought into contact with the surface of the photosensitive drum 4 with a predetermined pressure. Yes.
[0024]
Further, a magnet roller 23 and a conveying screw 24 are rotatably attached to the frame 21 and are driven to rotate by driving means (not shown). The magnet roller 23 has a toner layer formed of residual toner on the surface, and the regulation of the thickness of the toner layer is guaranteed by the clearance with the shaft 28. Then, the surface of the photosensitive drum 4 is recoated with toner by bringing the toner layer into contact with the longitudinal direction of the photosensitive drum 4. This is because the friction between the blade member 22 and the photosensitive drum 4 is stabilized in the longitudinal direction by re-coating the residual toner in the longitudinal direction of the photosensitive drum 4.
[0025]
The residual toner is scraped off by the blade member 22 together with the recoated toner, and collected by the magnet roller 23. By scraping the surface of the shaft 28, the sheet 25 has both the function of maintaining the toner layer thickness on the magnet roller 23 and the function of transporting residual toner to the transport screw 24. The transport screw 24 transports residual toner to a toner collection container (not shown).
[0026]
Here, the toner removing action by the blade member 22 will be described. FIG. 3 is an enlarged explanatory view of the main parts of the blade member 22 and the photosensitive drum 4 provided in the cleaning device 9.
[0027]
As shown in FIG. 3A, residual toner scraped off from the surface of the photosensitive drum 4 is aggregated at the edge portion of the blade member 22 in contact with the photosensitive drum 4.
[0028]
Then, as shown in FIG. 3B, when the aggregated residual toner continues to grow, the residual toner tries to pass through the nip 22a at the edge portion of the blade member 22. If the residual toner slips through at this time, an image on the streaks appears in the transfer material conveyance direction as described above, and an image defect occurs. For this reason, it is necessary to remove residual toner that has grown into aggregates from the edge of the blade member 22.
[0029]
Therefore, in the present embodiment, the motor provided in the motor unit 30 is intermittently rotated to apply vibration to the blade member 22.
[0030]
Next, a configuration for imparting vibration to the blade member 22 will be described. FIG. 4 is an explanatory diagram of the arrangement of the motor unit, and FIG. 5 is an explanatory diagram of the vibration configuration of the motor.
[0031]
In the present embodiment, as shown in FIG. 4, a plurality of motor units 30 are arranged on the frame 20. In the present embodiment, two motor units 30 are arranged at symmetrical positions with respect to the longitudinal center of the frame 20. As shown in FIG. 5, the motor unit 30 has a motor 32 attached in a case 31, and a fan-shaped weight 33 attached to an output shaft portion thereof. The motor 32 is connected to a control circuit (control means) (not shown).
[0032]
Since the fan-shaped weight 33 is attached to the motor 32 as described above, vibration is generated from the motor 32 when the motor 32 is rotationally driven. This vibration propagates to the frame 20 and further propagates to the blade member 22.
[0033]
The plurality of motor units 30 is not limited to the above configuration as long as the blade unit 22 is configured to give sufficient vibration to remove the aggregate.
[0034]
As a result of various experiments, it is more effective to increase the number of operations than to increase the operation time of one time of the motor 32 in order to remove the toner lump aggregated on the edge portion of the blade member 22. I found out. This is because the removal performance is improved by inputting the first shock vibration.
[0035]
For this reason, in this embodiment, the time for driving the motor 32 to conduct (on time) is set to the time for which the motor 32 is in steady operation (steady state) and its margin. On the other hand, the time (off time) during which the motor 32 is turned off and in the non-driven state is set to the time until the blade member 22 is completely stopped and the margin. Then, the drive control is performed so that the on / off intermittent drive of the motor 32 is repeated a plurality of times. As a result, vibration is propagated to the blade member 22 through the frame 20 (see FIG. 3C), so that the toner mass formed on the edge portion of the blade member 22 can be efficiently removed (FIG. 3 ( d)).
[0036]
Note that the timing for operating the motor 32 is not desirable because if the motor 32 is operated during image formation, the vibration propagates to the photosensitive drum 4 and the image is blurred. Therefore, it is desirable to operate at a predetermined timing other than during image formation.
[0037]
In the above-described embodiment, an example in which a fan-shaped weight 33 is attached to the output shaft of the motor 32 has been described. This is because the motor 32 efficiently generates vibration when the motor 32 rotates. As long as it is a shape that can sometimes generate vibrations, it need not be limited to a sector shape.
[0038]
【The invention's effect】
Since the present invention is configured as described above, vibration is imparted to the elastic blade by driving the motor, so that residual toner agglomerates can be efficiently removed, and high-quality image formation that does not cause image defects occurs. Is possible .
[0039]
Moreover, since it can be achieved with a small low-power motor, it is possible to simultaneously reduce power consumption and operating noise.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of an image forming apparatus.
FIG. 2 is a cross-sectional explanatory view of a cleaning device.
FIG. 3 is an enlarged explanatory view of main parts of a blade member and a photosensitive drum.
FIG. 4 is an explanatory view of arrangement of a motor unit.
FIG. 5 is an explanatory diagram of a vibration configuration of a motor.
FIG. 6 is an explanatory diagram of a toner lump generated at an edge portion of a blade member.
[Explanation of symbols]
A ... Recording unit B ... Image reading unit C ... Document feeding device S ... Transfer material 1 ... Cassette 2 ... Feeding roller 3 ... Conveying roller 4 ... Photoconductor drum 5 ... Primary charger 6 ... Exposure unit 7 ... Developing unit 8 ... Transfer unit 9 ... cleaning device
10 ... Conveyor belt
11… Fixing part
12… discharge roller
20… Frame
21… Frame
22… Blade material
22a ... Nip
23… Magnet roller
24… Conveying screw
25… Sheet
26… Blade holder
27… Shaft
28 Shaft
29… Spring
30… Motor unit
31… Case
32… Motor
33… Weight

Claims (2)

In a cleaning device for cleaning an image carrier,
An elastic blade for removing residual toner by contact with the image bearing member,
A motor that generates vibration by rotating a weight attached to the output shaft,
A frame for holding the elastic blade and the motor and transmitting vibrations generated by the motor to the elastic blade ;
Have
A cleaning device configured to intermittently and repeatedly drive the motor when the elastic blade is vibrated . The drive time of the motor is set longer than the time when the rotation speed of the motor is in a steady state, and the non-drive time of the motor is set longer than the time when the vibration of the frame or the elastic blade stops. The cleaning apparatus according to claim 1.

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