JP4622283B2 - Cleaning device and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device including a cleaning blade that removes foreign matter existing on a surface of a cleaning object whose surface is circulated, and an image forming apparatus including such a cleaning device.

  Conventionally, an electrostatic latent image formed on an image carrier is developed using a developer containing toner to form a toner image on the surface of the image carrier, and the toner image is transferred to a transfer surface. In the image forming apparatus of the type that is finally fixed on the recording medium, a cleaning blade for cleaning the residue remaining on the surface of the image carrier after the transfer of the toner image to the transfer surface is provided on the image carrier. Some are in contact.

  FIG. 1 is a schematic configuration diagram of a cleaning device using a cleaning blade.

  The cleaning device 100 shown in FIG. 1 is downstream of the transfer device 130 that transfers the toner image to the intermediate transfer belt 140 and upstream of the charger 120 in the rotation direction of the photoconductor 110 (direction of arrow A). The cleaning blade 101, the blade base 102 to which the cleaning blade 101 is attached, the housing 103, and the photoconductor 110 are in contact with the photoconductor 110 while rotating, and the residue on the photoconductor surface is disturbed. The rotating brush 104 assists scraping of the residue by the cleaning blade 101. In addition, a portion 103 a of the housing 103 knocks off the residue transferred from the photosensitive member 110 to the rotating brush 104 that contacts the photosensitive member 110 from the rotating brush 104 by contacting the rotating brush 104.

  The cleaning device 100 shown in FIG. 1 is generally called a constant displacement method, and the blade base 102 to which the cleaning blade 101 is attached has the tip of the cleaning blade 101 in a state where the photoconductor 110 is stationary. By being pressed against the surface of the photoconductor in a direction against the rotation direction A, the photoconductor surface is fixed to the housing 103 so as to bite into the photoconductor surface by about 1 mm.

  By the way, in the constant displacement type cleaning apparatus as shown in FIG. 1, it is known that the pressing pressure of the cleaning blade against the surface of the photosensitive member gradually decreases due to permanent deformation of the cleaning blade (hereinafter referred to as “sag”). Therefore, it is expected that it will become increasingly difficult to maintain the cleaning performance and the long-term cleaning performance of the toner whose diameter is reduced in order to cope with the higher quality of the image that is increasingly required in recent years.

  Therefore, a cleaning device called a constant load method has been proposed (for example, Patent Document 1).

  FIG. 2 is a schematic configuration diagram of a constant load type cleaning device.

  In the constant load cleaning device 200 shown in FIG. 2, the blade base 202 is rotatable about a shaft 2021 extending from the front side to the back side in FIG. 2, and the end portion 202 a of the base plate 202 and the housing 203 are rotated. The tip of the cleaning blade 201 is pressed against the surface of the photosensitive member by urging the spring 205 in a retracting direction by attaching the spring 205 to the mooring portion 203b erected on the surface.

  In the constant load type cleaning apparatus as shown in FIG. 2, a pressure to press the tip of the cleaning blade against the surface of the photosensitive member by an elastic member such as a spring acts on the cleaning blade. Therefore, it is possible to prevent a situation in which the pressure of pressing the tip of the cleaning blade against the surface of the photosensitive member due to the settling of the cleaning blade as in the constant displacement method is reduced. Thereby, according to the constant load type cleaning device, it is possible to cope with the reduction of the toner diameter. 2 will be described later.

  FIG. 3 is a view showing a state in which the cleaning blade of the cleaning device shown in FIG.

In FIG. 3, the surface is sandwiched between the cleaning blade 201 whose front end is pressed against the surface of the photoconductor and the surface of the photoconductor surface that extends from the portion where the front end of the cleaning blade 201 is pressed to the downstream side in the rotation direction of the photoconductor surface. It is shown that the angle (hereinafter referred to as the contact angle) (θ ′) is smaller than the contact angle (θ) of the cleaning blade 201 that has not yet been cut as shown in FIG. Yes.
JP 2001-228775 A

  In the case of a constant load type cleaning device, even if the cleaning blade is gradually pushed and becomes as shown in FIG. 3, the tip of the cleaning blade is continuously pressed against the surface of the photoreceptor by the biasing force of the spring. For this reason, it seems that the cleaning performance is maintained at first glance. However, as the cleaning blade progresses and the contact angle of the cleaning blade with respect to the surface of the photosensitive member decreases, the cleaning blade is not the tip but the cleaning blade. It is known that the surface of the photoconductor is cleaned by the belly portion of the blade, and the cleaning property is deteriorated.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a cleaning device devised to maintain the cleaning performance by a cleaning blade as much as possible, and an image forming apparatus provided with such a cleaning device.

In order to achieve the above object, the cleaning device of the present invention comprises:
The tip is brought into contact with the surface of the cleaning object that circulates in a predetermined direction, and is placed in a posture inclined to the downstream side in the circulation movement direction of the cleaning object with respect to a vertical line that rises perpendicularly from the surface. A cleaning blade that removes foreign matter present on this surface by being pressed,
A pressing member that presses the tip of the cleaning blade against the surface by extending or contracting;
And a restricting member that restricts the pressing member from extending or retracting beyond a predetermined length.

  In the present invention, when the cleaning blade is pressed in a direction against the circulation movement direction of the object to be cleaned, the settling of the cleaning blade advances to some extent and the contact angle becomes a predetermined angle or less. Focusing on the fact that the contact angle does not become smaller than the contact angle, the decrease in the cleaning performance is smaller than the contact angle keeps decreasing as it is in the conventional way. is there. If the contact angle is ensured above a certain level, the amount of deformation that the tip of the cleaning blade is deformed in the moving direction of the object to be cleaned is ensured, and this deformation does not reduce the stress too much, which is the reaction. It is inferred that this is because the reduction of the scraping power is prevented. In the cleaning device of the present invention, although the constant load method is adopted, the pressing member is restricted from extending or retracting a predetermined length or more, that is, the contact member has a contact angle of a predetermined angle or less. It is prevented. Therefore, according to the cleaning device of the present invention, the cleaning performance by the cleaning blade can be maintained as much as possible.

In order to achieve the above object, an image forming apparatus of the present invention comprises:
A toner image carrier that carries a toner image on its surface and rotates in a predetermined direction is provided. The toner image carried on the surface of this toner image carrier is transferred to a predetermined transfer surface and finally onto a recording medium. In an image forming apparatus that forms an image on this recording medium by fixing,
A posture of the toner image carrier inclined to the downstream side in the rotation direction of the toner image carrier with respect to a vertical line that rises perpendicularly from the surface of the toner image carrier after the toner image is transferred to the transfer surface. And a cleaning blade that removes foreign matter present on this surface by being deployed at this tip and being pressed against this surface;
A pressing member that presses the tip of the cleaning blade against the surface by extending or contracting;
And a restricting member that restricts the pressing member from extending or retracting beyond a predetermined length.

  Here, it is preferable that a reciprocating mechanism for reciprocally moving the tip of the cleaning blade and the surface of the toner image carrier in the extending direction of the rotation shaft of the toner image carrier is provided.

  If, for example, a toner external additive or the like remaining on the surface of the toner image carrier without being transferred to the transfer surface is sandwiched between the toner image carrier and the cleaning blade, the cleaning blade and the toner image carrier In the prior art, which is fixedly provided, an external additive or the like is supposed to damage the toner image carrier at the same location on the toner image carrier. On the other hand, by doing in this way, it can be avoided that a predetermined portion of the toner image carrier is deeply damaged by an external additive or the like. Therefore, in this case, it becomes difficult to form extreme unevenness on the surface of the toner image carrier, and thus the cleaning blade can be protected from scratches and long-term cleaning performance can be ensured.

  According to the cleaning device and the image forming apparatus of the present invention, the cleaning performance by the cleaning blade can be maintained for a long time.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 4 is a schematic configuration diagram of an embodiment of the image forming apparatus of the present invention, which includes an embodiment of the cleaning apparatus of the present invention.

  As shown in FIG. 4, the printer 1 of the present embodiment includes four image forming units 10Y, 10M, 10C, and 10K. Each image forming unit has a photosensitive element that rotates in the direction of arrow B. Bodies 11Y, 11M, 11C, 11K, chargers 13Y, 13M, 13C, 13K, exposure devices 14Y, 14M, 14C, 14K, developing rolls 12Y, 12M, 12C, 12K, primary transfer rolls 20Y, 20M, 20C, 20K, In addition, there are provided cleaning units 15Y, 15M, 15C, and 15K in which a rotating brush for supplying a lubricant, a cleaning blade, a flicking member, and the like are provided. The printer 1 can perform full-color printing, and the symbols Y, M, C, and K added to the end of each of the above components are yellow, magenta, cyan, and black images, respectively. It is a component for formation. The cleaning section referred to here corresponds to an example of the cleaning device of the present invention.

  The printer 1 is also provided with an intermediate transfer belt 30, a secondary transfer roll 40, and a tension roller 31 that circulate in the direction of arrow C.

  A basic image forming operation of the printer 1 will be described.

  In this printer 1, first, toner image formation by the yellow image forming unit 10Y is started, and a predetermined charge is applied to the surface of the photoreceptor 11Y rotating in the direction of arrow B by the charger 13Y. Next, exposure light corresponding to the yellow image generated by the exposure device 14Y is irradiated onto the surface of the photoconductor 11Y to form an electrostatic latent image. The electrostatic latent image is developed with yellow toner by the developing roller 12Y to form a yellow toner image on the photoreceptor 11Y. The toner image is transferred to the intermediate transfer belt 30 by the primary transfer roll 20Y.

  In this printer 1, toner development (visualization) of an electrostatic latent image formed on a photoconductor is performed using a developer containing a magnetic carrier and an external additive in addition to toner.

  The intermediate transfer belt 30 receives the magenta toner image of the next color in accordance with the timing at which the yellow toner image transferred onto the intermediate transfer belt 30 reaches the primary transfer roll 20M of the image forming unit 10M of the next color. A toner image is formed by the magenta image forming unit 10M so as to reach the primary transfer roll 20M. The magenta toner image formed in this way is transferred onto the yellow toner image on the intermediate transfer belt 30 while being superimposed on the primary transfer roll 20M.

  Subsequently, toner image formation by the cyan and black image forming units 10C and 10K is performed at the same timing as described above, and sequentially superimposed on the yellow and magenta toner images of the intermediate transfer belt 30 in the primary transfer rolls 20C and 20K. Is transcribed.

  Thus, the multicolor toner image transferred onto the intermediate transfer belt 30 is finally secondarily transferred onto the paper 200 by the secondary transfer roll 40, and the multicolor toner image is conveyed along with the paper 200 in the direction of arrow D. A color image is formed on the sheet 200 by being fixed by a fixing device that does not. In the following, since the functions of the image forming units for Y, M, C, and K are the same, the Y (yellow) color image forming unit 10Y will be representatively described.

  FIG. 5 is a schematic configuration diagram of the cleaning unit of the yellow image forming unit shown in FIG.

  The cleaning unit 15Y of the yellow image forming unit 10Y shown in FIG. 5 includes a housing 150Y, a cleaning blade 155Y, a cleaning blade 155Y, and a rotating arm 151Y that is rotatable about a rotating shaft 1511Y. A cam pin 156Y that is fixed to the rotating arm 151Y and has a leading end 1561Y in a cam groove 111Y (see FIG. 6) provided on one peripheral edge of the photoreceptor 11Y, and an upper surface of the housing 150Y. And a fixed arm 157Y provided with a long hole 1571Y, and a rotating brush 154Y that disturbs the residue remaining on the surface of the photoreceptor 11Y. The elongated hole 1571Y shown in FIG. 5 extends from the front side of the drawing toward the back.

  The cleaning unit 15Y passes through a long hole 1571Y provided in the fixed arm 157Y and is screwed into a screw groove 1512Y provided on the upper surface side of the rotating arm 151Y, and a lower surface of the fixed arm 157Y. It is arranged in a state of being biased in a direction extending between the upper surface of the rotary arm 151Y, that is, a direction in which the end 1513Y of the rotary arm 151Y is pushed down (arrow E), and penetrated by the bolt 152Y. And a spring 153Y. Note that the portion 1501Y of the housing 150 knocks down the residue that has moved from the photosensitive member side to the rotating brush 154Y when the rotating brush 154Y contacts the photosensitive member 11Y while rotating.

  With the configuration described above, the movable arm 151Y is biased in the direction in which the end 1513Y rotates downward (arrow F) by the spring 153Y, and the cleaning blade 155Y is photosensitive by this biasing. The contact angle shown in FIG. 5 is reduced to a predetermined angle so that the contact angle shown in FIG. 5 becomes too small and the cleaning performance does not deteriorate as the cleaning blade 155Y advances. When it reaches, the head 1521Y of the bolt 152Y and the fixed arm 157Y come into contact with each other, and the movable arm 151Y does not rotate too much in the direction of the arrow F. Here, the predetermined angle can be changed by tightening or loosening the bolt 152Y.

  In the cleaning unit provided in the printer 1, although the constant load method is adopted, excessive rotation of the rotating arm 151Y in the direction of the arrow F is restricted, and the contact angle θ is set to a predetermined angle or less. It is prevented from becoming. Therefore, in this printer 1, the scraping power of the residue remaining on the photoreceptor surface 11Y is not reduced excessively, and the cleaning performance by the cleaning blade 155Y can be maintained as much as possible.

  6 is a view of the cleaning unit shown in FIG. 5 when viewed from the upper right of FIG.

  As shown in FIG. 6, in the cleaning unit 15Y, the rotation shaft 1511Y of the rotation arm 151Y is supported by the housing 150Y. Further, as described above, the tip 1561Y of the cam 156Y enters the cam groove 111Y provided at one peripheral edge of the photoconductor 11Y so as to meander in the left-right direction in FIG. 6, and the photoconductor 11Y rotates. As a result, the pivot arm 151Y reciprocates in the left-right direction in FIG. Note that a long hole 1571Y is provided in the fixed arm 157Y provided upright on the upper surface of the housing 150Y, and even if the rotary arm 151Y reciprocates in the left-right direction in FIG. 6, the upper surface of the rotary arm 151Y. The bolt 152Y screwed into the screw groove 1512Y provided on the side can reciprocate in the left-right direction in FIG. 6 together with the rotating arm 151Y. When, for example, an external additive of toner remaining on the surface of the photosensitive member without being transferred to the intermediate transfer belt 30 (see FIG. 4) is sandwiched between the photosensitive member 11Y and the cleaning blade 155Y, the cleaning blade 155Y and the photosensitive member are exposed. Conventionally, the photoconductor 11Y is fixedly provided on the surface of the photoconductor 11Y, but the photoconductor 11Y is damaged at the same location on the surface of the photoconductor 11Y. However, it is possible to avoid the predetermined portion from being deeply damaged. Therefore, by doing so, the cleaning blade can be protected from scratches, and furthermore, a stable and high-quality image output can be provided over a long period of time. In addition, this can also contribute to prevention of the cleaning blade from turning.

  In Example 1 shown in Table 1, the image forming apparatus of DocuCenter Color500 manufactured by Fuji Xerox was modified, and the printer 1 having the cleaning unit described above was left for 3 days in an environment of 42 ° C. and 85%. After outputting 12,000 A4 full-color images in a high-temperature, high-humidity (H / H) environment (28 ° C., 85%), and then in a low-temperature, low-humidity (L / L) environment (10 ° C., 15%) after outputting 34,000 continuous A3 solid images (black single color) after outputting 24,000 images, and then outputting 10,000 A4 full-color images under H / H environment for 2 days The evaluation of the image quality after the output of the black single color 30% halftone image after being left is shown. In the printer 1, yellow, magenta, and cyan color toners having a shape factor of 132 are used, and black toner having a shape factor of 125 is used. As a result, in the first H / H environment, the L / L environment, and the second H / H environment, no image flow occurred and a good image quality was obtained. Further, when the rotational torque of the photosensitive member at this time was measured, it was 8 kgf · m.

  Comparative Example 1 shown in Table 1 shows the same H / H environment and L / L environment as in Example 1 when the bolt 152Y that restricts the contact angle is removed from the cleaning device of the printer 1. The evaluation of the image quality in the second H / H environment is shown. Although there was no problem in the first H / H environment, black streaks occurred in the L / L environment, and the cleaning property was improved. It has confirmed that it has fallen. Further, it was confirmed that the image flow occurred under the second H / H environment, and the refreshability of the surface of the photoreceptor was lowered. Further, when the rotational torque of the photosensitive member at this time was measured, it was 4.5 kgf · m.

  In Comparative Example 2 shown in Table 1, in place of the cleaning unit of the printer 1, the same displacement as that in Example 1 in the case of using a constant displacement type, under the first H / H environment, under the L / L environment, The evaluation of the image quality in the second H / H environment is shown. As a result, slight density unevenness and image flow occur in the first H / H environment, and black in the L / L environment. Streaks were confirmed. In addition, in the second H / H environment, an image flow having a small density is generated on a halftone having a density of 30%, but it can be confirmed that the refreshability of the surface of the photoreceptor is degraded. It was. Further, when the rotational torque of the photosensitive member at this time was measured, it was 4 kgf · m.

  According to the embodiment, in the printer 1, since the contact angle is prevented from being a predetermined angle or less, the force for deforming the blade tip in the rotation direction of the photoconductor 11Y does not decrease too much, and the reaction thereof. It can be seen that the scraping power is maintained more than before.

  From Comparative Example 1 and Comparative Example 2, it can be read that the cleaning blade appears as a deterioration of the cleaning property as it is, and the photosensitive member is made of toner or an external additive between the surface of the photosensitive member and the tip of the cleaning blade. It can also be seen that the refresh function of the surface is lowered by the fact that the antinode of the cleaning blade finally comes into contact with the surface of the photoreceptor. Therefore, the rotational torque of the photosensitive member in Comparative Example 1 and Comparative Example 2 is also lower than that in the example.

  As described above, according to the printer 1, even when the constant load method is adopted, the cleaning performance by the cleaning blade can be maintained as compared with the conventional one. In the printer 1, the predetermined installation angle can be changed by tightening or loosening the bolt 152Y.

  In the embodiment described above, as shown in FIG. 5, the spring 153Y biased in the extending direction is arranged between the fixed arm 157Y and the rotary arm 151Y, so that the rotary arm 151Y is moved to the arrow. F is rotated in the direction of F, and the cleaning blade 155Y is pressed against the photoconductor 11Y, and a bolt 152Y that passes through the fixed arm 157Y and the spring 153Y is inserted is screwed into the rotation arm 151Y, and the arrow of the rotation arm 151Y The case where excessive rotation in the direction of F is prevented has been described as an example. However, the present invention is not limited to this mode, and is attached to a direction in which the rotating arm 151Y and the housing portion 1501Y contract. A stopper such as a bolt may be provided so as to extend the biased spring and prevent excessive degeneration. In addition, a spring other than a spring may be used as long as it can press a cleaning blade provided against the rotation direction of the photoconductor against the photoconductor.

It is a schematic block diagram of the cleaning apparatus using a cleaning blade. It is a schematic block diagram of the constant load type cleaning apparatus. It is a figure which shows a mode that the cleaning blade of the cleaning apparatus shown in FIG. 1 is a schematic configuration diagram of an embodiment of an image forming apparatus of the present invention including an embodiment of a cleaning apparatus of the present invention. FIG. 5 is a schematic configuration diagram of a cleaning unit of the yellow image forming unit shown in FIG. 4. It is a figure at the time of seeing the cleaning part shown in FIG. 5 from the upper right part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 11Y Photoconductor 15Y Cleaning part 150Y Housing 1501Y Part 151Y Rotating arm 1511Y Rotating shaft 1512Y Screw groove 1513Y End part 152Y Bolt 1521Y Head part 153Y Spring 154Y Rotating brush 155Y Cleaning blade 156Y Long hole 156Y71

Claims (2)

The tip is brought into contact with the surface of the cleaning object that circulates in a predetermined direction, and is arranged in a posture inclined to the downstream side in the circulation movement direction of the cleaning object with respect to a vertical line that rises perpendicularly from the surface. A cleaning blade that removes foreign matter present on the surface by being pressed;
The cleaning blade is fixed, the tip of the cleaning blade is brought into contact with the surface of the cleaning object, and relative reciprocation between the cleaning object and the cleaning object is performed in a direction perpendicular to the circulating movement direction of the cleaning object. Possible fixing parts,
Along with the reciprocating movement of the fixing portion, the cleaning object can be reciprocated relative to the cleaning object in a direction perpendicular to the circulating movement direction, and the fixing part can be fixed by being expanded or contracted. A pressing member that presses the tip of the cleaning blade against the surface of the cleaning object via a portion;
A restricting member that restricts the pressing member from extending or retracting beyond a predetermined length;
A cleaning device comprising: a cam member extending from the fixed portion; and a cam member entering a cam groove provided meandering in a direction perpendicular to the circulation movement direction on the surface of the cleaning object. . A toner image carrier that carries a toner image on its surface and rotates in a predetermined direction is provided. The toner image carried on the surface of the toner image carrier is transferred to a predetermined transfer surface and finally onto a recording medium. In an image forming apparatus that forms an image on the recording medium by fixing,
The tip is brought into contact with the surface of the toner image carrier, and is arranged in a posture inclined to the downstream side in the rotation direction of the toner image carrier with respect to a perpendicular rising vertically from the surface, and the tip is pressed against the surface. A cleaning blade for removing foreign substances present on the surface;
The cleaning blade is fixed, the tip of the cleaning blade is brought into contact with the surface of the toner image carrier, and between the toner image carrier and the toner image carrier in the extending direction in which the rotation shaft of the toner image carrier extends. A fixed part capable of relative reciprocation;
Along with the reciprocating movement of the fixing portion, the reciprocating movement relative to the toner image carrier is possible in the extending direction in which the rotation axis of the toner image carrier extends, and the toner image carrier expands or contracts. A pressing member that presses the tip of the cleaning blade against the surface of the toner image carrier via the fixing portion;
A restricting member that restricts the pressing member from extending or retracting beyond a predetermined length;
An image forming apparatus comprising: a cam member extending from the fixed portion; and a cam member entering a cam groove provided meandering in the extending direction on the surface of the toner image carrier.

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