JPH07230239A - Cleaning device of image forming device - Google Patents

Abstract

PURPOSE:To provide a cleaning device of image forming device capable of restoring a blade to be in the original state by detecting the state when the coefficient of friction between the photoreceptor and the blade becomes large and the blade is deformed in a bending shape with the friction. CONSTITUTION:A blade 4 is fitted to a blade supporting body 2 arranged in the side part of a photoreceptor 1 of a drum-shape, the end part of the blade 4 is held in press-contact with the surface of the photoreceptor 1 oriented in the reverse direction to the rotary direction of the photoreceptor 1, and the strain gauges 6a and 6b are fitted on the both end part surface of the blade 4. When the coefficient of friction between the photoreceptor 1 and the blade 4 becomes large, the blade 4 is deformed into the bending shape with the friction, and the output of strain gauges 6a and 6b become larger than a normal value, a switching 11 is operated by a controller 14, a developing roller 9 is switched over from a DC power source 10 to a grounding 12, and the toner of the developing roller 9 is made stuck in the non-image area on the photoreceptor 1. Then, the toner of the photoreceptor is supplied to the blade 4 deformed into the bending shape, thus the blade 4 is restored to be in the original state.

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 such as an electrostatographic copying machine, a facsimile or a printer.
A cleaning device using a blade for removing residual toner on the surface of a photoconductor such as a drum, and relates to a counter type cleaning device in which the blade is arranged in a direction opposite to the traveling direction of the photoconductor.

[0002]

2. Description of the Related Art As a cleaning device for removing residual toner on a photoconductor in an electrostatic photocopier or other image forming apparatus, the tip edge portion of a blade made of an elastic material is pressed against the surface of the photoconductor. It is known that the residual toner on the surface of the photoconductor is separated at the edge portion. In a cleaning device using this blade, a counter method is known in which the blade is fixedly arranged in the direction opposite to the traveling direction of the photoconductor, and the tip edge portion thereof is appropriately pressed against the surface of the photoconductor. The counter type cleaning device using this blade is arranged so that the edge portion of the blade abuts the surface of the photoconductor, and the residual toner on the surface of the photoconductor is peeled off at the edge portion, so that the residual toner Even when the amount of toner is large, the residual toner can be efficiently removed.

When the blade removes the residual toner on the surface of the photoconductor, the removed residual toner comes to be present between the surface of the photoconductor and the blade, and between the surface of the photoconductor and the blade. Since the residual toner intervening therein acts as a lubricant, the coefficient of friction between the surface of the photoconductor and the blade becomes small, and the photoconductor advances smoothly with respect to the blade. In this way, the residual toner serves as a lubricant, thereby preventing the blade from affecting the photosensitive film on the surface of the photosensitive member and reducing the wear of the edge portion of the blade to prolong the life of the blade.

[0004]

In the conventional cleaning device using the blade, the residual toner on the photoconductor is present in an amount that can serve as the lubricant, and the abrasion of the edge portion of the blade is small. As a result, under the condition that the friction coefficient between the photoconductor and the blade is equal to or less than the set value, the photoconductor advances smoothly with respect to the blade, and the blade maintains the state in which It is possible to continue the removal. However, the amount of toner remaining on the surface of the photoconductor and reaching the blade fluctuates depending on the ratio of the white part to other color parts of the document and the change in transfer efficiency due to changes in the environment. If the copying is continuously performed, the amount of residual toner on the surface of the photosensitive member decreases, the amount of toner reaching the blade decreases, and the lubrication effect of the toner on the blade decreases. Further, since the counter-type blade comes in relatively strong contact with the surface of the photoconductor, the edge portion of the blade is easily worn, and the surface roughness of the photoconductor changes with time. The coefficient of friction of changes gradually.

Therefore, in a cleaning device using a counter type blade, the amount of abrasion of the blade increases, the surface roughness of the photosensitive member changes, and the amount of residual toner supplied to the blade decreases. As a result, the lubrication effect becomes insufficient and the friction coefficient between the surface of the photoconductor and the blade becomes larger than the set value. In this way, when the friction coefficient between the surface of the photoconductor and the blade becomes large, the friction causes the tip side part of the blade to bend elastically in the same direction as the photoconductor advances from the tip side at the end in the length direction. Then, for example, in FIG. 6 (a), (b), (c),
As shown in (d), the blade B sequentially bends and winds up relative to the photoconductor A, and the tip side portion of the blade B is bent and comes into a state of being pressed against the surface of the photoconductor A. Happens.

As shown in FIGS. 6 (a), 6 (b), 6 (c) and 6 (d), when the tip portion of the blade B is bent in the advancing direction of the photoconductor A, cleaning may be defective. , The friction coefficient between the surface of the photoconductor A and the blade B becomes large, and the load on the progress of the photoconductor A becomes too large.
There is also a possibility that the drive mechanism of will be damaged. Further, there are problems that the surface of the photoconductor A and the blade B are greatly affected, and cleaning by the blade becomes difficult, which makes it difficult to use the image forming apparatus.

The present invention is to solve the above problems, and in a cleaning device using the counter type blade, the friction coefficient between the photosensitive member and the blade is increased, and the friction causes the tip of the blade. When the side moves toward the advancing direction of the photoconductor and the blade is bent in the direction of separating from the photoconductor, the bending deformation is detected and the blade is returned to the original state. An object of the present invention is to provide a cleaning device for an image forming apparatus, which enables the influence of the blade and the surface of the photosensitive member.

[0008]

In a cleaning device for an image forming apparatus of the present invention, a blade made of an elastic material is directed in the direction opposite to the advancing direction of the photoconductor, and the edge portion on the tip side of the photoconductor is set to the photoconductor. In the cleaning device of the image forming apparatus that is pressed against the surface of the photoconductor, the friction coefficient between the photoconductor and the blade becomes large, and the friction moves the tip side of the blade toward the advancing direction of the photoconductor. Deformation detection means is provided for detecting the curved deformation of the blade when the blade is deformed in the separating direction. Based on the detection signal of the deformation detection means, toner is applied to the non-image area of the photoconductor by the developing means. Is attached and the toner is supplied to the blade.

A strain gauge or a limit switch may be used as the blade deformation detecting means. Strain gauges are attached to the surface of the blade to detect blade bending as the friction increases. The limit switch is arranged on the side of the blade opposite to the photoconductor, and the actuator is pushed by the curved and deformed portion of the blade to be operated. Although the position of the deformation detecting means such as a strain gauge or a limit switch with respect to the blade can be arbitrarily selected, the curved deformation of the blade caused by an increase in friction between the photoconductor and the blade is It originates from each end in the depth direction. Therefore, it is suitable to arrange the deformation detecting means at both ends of the blade.

When the deformation detecting means of the blade detects the curved deformation of the blade, the developing means applies toner to the non-image area of the photosensitive member by applying a developing bias to the developing means. There is a means for cutting off the power supply or adjusting the voltage to a low voltage so that the toner attached to the surface of the developing means is attached to the non-image area of the photoconductor. In addition, there is a means for charging the non-image area of the photoconductor with a charging device and attaching the toner of the developing means to the non-image area.
In this means for charging the non-image area of the photoconductor with the charger, the non-image area of the photoconductor charged by the charger is irradiated with a light beam having a reduced illuminance to reduce the electrostatic charge in the non-image area. The voltage to be adjusted or applied to the charger is lower than the voltage for charging the image area, for example, 200 to 30.
If the non-image area of the photoconductor is charged with the charger to adjust the electrostatic charge to a small value, the amount of toner attached to the non-image area is adjusted to a level necessary as a lubricant for the blade. It is possible to use the toner efficiently.

[0011]

In the cleaning device of the image forming apparatus of the present invention, the residual toner on the surface of the photoconductor is removed by the blade arranged in the direction opposite to the advancing direction of the photoconductor. When the blade removes residual toner, abrasion of the blade edge progresses, and the amount of residual toner on the surface of the photoconductor decreases significantly, resulting in insufficient lubrication of the photoconductor and blade by the toner. The friction coefficient between the body and the blade may become larger than the set value. When the friction coefficient becomes large as described above, the tip side of the blade moves to the advancing direction side of the photoconductor due to the friction, and when the blade is bent and deformed in the direction of separating from the photoconductor surface,
The deformation detecting means detects the curved deformation of the blade.
Then, based on the detection signal, the developing unit adheres the toner to the non-image area of the photoconductor, and the photoconductor supplies the toner to the blade as a lubricant to reduce the friction coefficient between the photoconductor and the blade. , The bent blade is restored to its original state.

When a strain gauge is used as the deformation detecting means for the blade, the strain gauge is attached to the surface of the blade, so that the strain gauge does not deform the blade due to an increase in friction between the photosensitive member and the blade. It directly detects and outputs a signal. When a limit switch is used as the deformation detection means, when the blade is bent in the direction of separating from the photoconductor due to increased friction, the bent portion pushes the actuator of the limit switch to operate the limit switch. The switch outputs a detection signal. The limit switch is arranged at a slight distance from the blade or in a state where the actuator is in slight contact with the blade, and the limit switch does not affect replacement of the blade.

Based on the output signal of the deformation detecting means of the blade, the adhesion of toner by the developing means to the non-image area of the photoconductor is adjusted by shutting off the DC power supply for applying the developing bias to the developing means or adjusting it to a low voltage. If the toner adhering to the surface of the developing means is adhered to the non-image area of the photoconductor which is not charged, the adhering amount of the toner can be made sufficiently small as a lubricant for the blade. In addition, when the non-image area of the photoconductor is charged by a charger and irradiated with light rays with reduced illuminance, and when the voltage applied to the charger is lower than the voltage for charging the image area, Even when the non-image area of the photoconductor is charged, the amount of toner attached to the non-image area can be reduced to a small amount suitable as a lubricant for the blade.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a cleaning device for an image forming apparatus of the present invention will be described with reference to FIGS. In FIGS. 1 and 2, 1 is a photosensitive member that is drum-shaped and is rotatably mounted, and 2 is a blade support that is arranged on a side portion of the surface of the photosensitive member 1, and the photosensitive member 1 is located at an intermediate portion thereof. Is supported by a support shaft 3 so as to be rotatable in the radial direction. 4 is a blade made of an elastically deformable material such as polyurethane in the shape of a strip plate,
This blade 4 is directed in the direction opposite to the rotation direction of the photoconductor 1, its edge is fixed to the end of the blade support 2, and the edge of the tip side contacts the surface of the photoconductor 1 in a counter method. ing. Reference numeral 5 denotes an urging spring of the blade support 2 attached to the end of the blade support 2 opposite to the blade 4 side. The urging spring 5 moves the blade 4 through the blade support 2 to the surface of the photoreceptor 1. Is pressed against. Strain gauges 6a and 6b are attached to the surfaces of both ends of the blade 4 as deformation detecting means, and these detect strain deformation of the blade 4.

Reference numeral 7 is a charger which is arranged in the axial direction of the surface of the photoconductor 1 facing the surface of the photoconductor 1, 8 is an exposure device which exposes the surface of the photoconductor 1 charged by the charger 7, and 9 is a developing means. Developing roller, 10 is a DC power source for applying a developing bias to the developing roller 9, and 11 is switching arranged between the developing roller 9 and the DC power source 10. This switching 11 disconnects the developing roller 9 from the DC power source 10. It is configured so that it can be connected to the earth 12 through the earth. 13 is strain gauge 6a, 6
An amplifier for amplifying the output signal of b, which is connected to the control device 14 to output the output signals of the strain gauges 6a, 6b to the control device.
Enter in 14. Then, when the output signals of the strain gauges 6a and 6b become larger than the normal values and the non-image area of the photoconductor 1 passes through the developing nip portion, the control device 14 operates the switching 11 so that the developing roller 9 is turned on. It is configured to be disconnected from the DC power supply 10 and connected to the ground 12. Reference numeral 15 is a collector for the residual toner removed from the photoconductor 1 by the blade 4.

In the cleaning device of the image forming apparatus constructed as described above, the blade 4 arranged in the direction opposite to the advancing direction shown by the arrow of the photoconductor 1 removes the residual toner on the surface of the photoconductor 1. Remove while taking. The amount of abrasion of the blade 4 increases due to the removal of the residual toner, and the friction coefficient between the photoconductor 1 and the blade 4 becomes smaller than the set value in response to the reduction of the residual toner amount supplied to the blade 4 and other conditions. Can be quite large. In this way, the coefficient of friction increases, and the friction causes the tip side of the blade 4 to move from the end to the advancing direction of the photoconductor 1.
As shown in FIG. 6 (c), when the blade 4 is bent and deformed in the direction separating from the surface of the photoconductor 1, the strain of the blade 4 due to the deformation is reduced by the strain gauges 6a, 6b.
Since both or one of them is detected, the output signals of the strain gauges 6a and 6b input to the control device 14 become larger than normal values.

Then, when the non-image area of the photosensitive member 1 passes through the developing nip portion, the control device 14 outputs a signal to switch the switching 11 from the DC power supply 10 side to the ground 12 side. For this reason, the electric charge of the developing roller 9 is discharged to the ground 12, so that a small amount of toner on the developing roller 9 adheres to the uncharged non-image area of the photoconductor 1 and the toner is bent and deformed. 4 is supplied. The toner supplied to the blade 4 serves as a lubricant, and the photoconductor 1
The coefficient of friction between the blade and the blade 4 is reduced. Therefore,
The curved and deformed blade 4 returns to a state close to the original straight line. Thus, for example, as shown in FIG. 6D, before the tip of the blade 4 is bent on the surface of the photoconductor 1, the deformation of the blade 4 is detected and the blade 4 is returned to its original state. As described above, when the blade 4 returns to the normal form, the control device 14 switches the switching 11 from the ground 12 side to the DC power source 10 side to enable the use of the image forming apparatus.

In the first embodiment, the developing roller 9 is switched from the DC power source 10 to the ground 12 by the switching 11 so that the toner can be attached to the non-image area of the photoconductor 1, but the ground 12 of the switching 11 is used. It is also possible to connect a DC power source having a voltage lower than that of the DC power source 10 to the side, adjust the developing bias applied to the developing roller 9 to a low voltage, and attach toner to the non-image area of the photoconductor 1. .

Further, instead of switching the DC power source 10,
When the strain gauges 6a and 6b detect the deformation of the blade 4,
It is also possible that the control device 14 charges the non-image area of the photoconductor 1 with the charger 7 and causes the developing roller 9 to adhere the toner to the non-image area. In this case, the voltage of the light source (not shown) of the exposure device 8 is adjusted to be low, and the non-image area of the charged photoconductor 1 is irradiated with the light beam having the reduced illuminance to reduce the electrostatic charge in the non-image area. It is also possible to adjust the amount of toner that adheres to a small amount suitable for lubricating the blade 4. It is also possible to adjust the voltage of the charging device 7 to a low value in advance and then charge the non-image area of the photoconductor 1 to adjust the amount of toner attached to the non-image area to a small amount as described above.

3 to 5 show a second embodiment. In FIGS. 3 to 5, reference numeral 1 denotes a photoconductor, 22 denotes a blade support, which is supported by a support shaft 23 so as to be rotatable in the radial direction of the photoconductor 1.
Reference numeral 24 denotes an elastically deformable blade, the edge of which is fixed to the blade support 22 in the direction opposite to the rotational direction of the photoconductor 1 indicated by the arrow. 25 is a blade support
The weight fixed to the blade 22 and the blade support 22
Is urged to press the edge portion of the blade 24 on the tip side against the surface of the photoconductor 1. Reference numeral 26 is a limit switch fixed to the blade support 22 as a deformation detecting means, and its actuator 26a is in light contact with the surface of the blade 24 opposite to the photoconductor 1. The limit switches 26 are arranged at both ends of the blade 24 in the length direction. The other structure is the same as that of the first embodiment, and therefore, the same reference numerals are given.

In the second embodiment, the photoconductor 1 and the blade 24 are used.
Has a large coefficient of friction, and due to the friction, the tip end side of the blade 24 moves toward the advancing direction of the photoconductor 1,
However, for example, as shown by the solid line in FIG. 5, when it is bent and deformed in the direction separating from the surface of the photoconductor 1, the bent and deformed portion pushes the actuator 26a of the limit switch 26 to move it. Inputs the detection signal to the control device (not shown). Then, the controller adjusts the voltage applied to the charger 7 to a low value of about 200 to 300 V to charge the non-image area of the photoconductor 1 so that the developing roller 9 adheres the toner to the non-image area. At this time, the amount of toner that adheres decreases because the electrostatic charge in the non-image area is adjusted to be small. A small amount of toner attached to the blade 24 is supplied as a lubricant to the curved and deformed blade 24, and the blade 24 returns to a state close to the original straight line shown by the chain line. When the blade 24 returns to its original form, the control device returns the voltage to the charger 7 to the original high voltage, for example, 800V. The toner can be attached to the non-image area of the photoconductor 1 by the other means shown in the first embodiment.

[0022]

As described above, in the cleaning device for the image forming apparatus of the present invention, the friction coefficient between the blade and the photosensitive member arranged in the counter method with respect to the photosensitive member becomes larger than the set value, and the friction When the blade is bent and deformed in a direction away from the photoconductor, the deformation is detected by the deformation detection unit, toner is attached to the non-image area of the photoconductor, and the toner is used to separate the photoconductor and blade. Reduce the coefficient of friction and return the blade to its original condition. Therefore, it is possible to prevent the blade and the surface of the photoconductor from bending due to the friction and the influence on the surface of the photoconductor or the drive unit of the photoconductor.

In the cleaning device of the image forming apparatus according to the second aspect of the present invention, the strain gauge is directly attached to the surface of the blade as the deformation detecting means to detect the curved deformation amount of the blade. Therefore, the deformation amount of the blade is efficiently detected. It is possible to Therefore, when the amount of curved deformation of the blade is relatively small, the deformation can be detected and returned to the original state, and the life of the blade can be extended.

In the cleaning device of the image forming apparatus according to the third aspect of the present invention, the limit switch is used as the deformation detecting means, and the actuator is placed in contact with or slightly spaced from the blade. When the set amount is reached, it can be accurately detected, and the blade can be reliably returned to the linear state. Moreover, the influence of the limit switch on the replacement of the blade is small and easy.

According to the cleaning device of each of the image forming apparatuses of claims 4, 5, and 6, the amount of toner adhered to the non-image area of the photoconductor can be adjusted to an extent suitable for the lubricant of the blade. It is possible to efficiently use the toner to restore the deformed blade to the original state.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a plan view of the blade of the first embodiment.

FIG. 3 is a schematic configuration diagram of a second embodiment.

FIG. 4 is a bottom view of a limit switch according to a second embodiment.

FIG. 5 is an explanatory diagram of blade deformation detection according to the second embodiment.

FIG. 6 is an explanatory diagram when the tip of the blade is bent.

[Explanation of symbols]

1: photoconductor, 4: blade, 6a, 6b: strain gauge,
7: charger, 8: exposure device, 9: developing roller, 10: DC power supply, 24: blade, 26: limit switch, 26a: actuator.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location G03G 21/00 520 (72) Inventor Takashi Nagashima 1-228 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Mita Industry Co., Ltd. (72) Inventor Hitoshi Nagahama 1-22 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Industry Co., Ltd.

Claims (6)

[Claims] 1. A cleaning device for an image forming apparatus, wherein a blade made of an elastic material is directed in a direction opposite to a traveling direction of a photoconductor, and an edge portion of the blade is pressed against a surface of the photoconductor. When the friction coefficient between the body and the blade becomes large, the tip side of the blade moves to the advancing direction side of the photoconductor due to the friction, and when the blade is bent in the direction of separating from the photoconductor surface, the blade of the blade is bent. Deformation detection means for detecting a bending deformation is provided, and based on a detection signal of the deformation detection means, toner is attached to the non-image area of the photoconductor by the developing means, and the toner is supplied to the blade. And a cleaning device for the image forming apparatus. 2. The cleaning device for an image forming apparatus according to claim 1, wherein a strain gauge is attached to the surface of the blade as a deformation detecting means of the blade. 3. A limit switch is arranged on the opposite side of the blade from the photoconductor as a deformation detecting means of the blade, and the tip end side of the blade is moved to the advancing direction side of the photoconductor by friction between the photoconductor and the blade, and the blade is moved. 2. The cleaning device for an image forming apparatus according to claim 1, wherein the curved deformation portion of the blade pushes the actuator of the limit switch to output a signal when it is curved and deformed in the direction of separation from the surface of the photoconductor. 4. The developing means for applying a developing bias to a DC power source is cut off or adjusted to a low voltage, and the developing means causes toner to adhere to the non-image area of the photoconductor. Image forming apparatus cleaning device. 5. The non-image area of the photoconductor charged by the charger is irradiated with a light beam having a reduced illuminance, and then the toner is attached to the non-image area by the developing means. A cleaning device for the image forming apparatus described. 6. The non-image area of the photoconductor is charged by a charger to which a voltage lower than the voltage of the image area is applied, and the toner is adhered to the non-image area by a developing means. A cleaning device for an image forming apparatus according to item 1.