JP2012155267A - Cleaning device, process unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device that detects level of vibration generated from a blade member that is a vibration source, and automatically suppresses the noise based on the detection result, without changing at all the slide-contact state of the blade member and an image carrier.SOLUTION: A cleaning device includes: a vibration detection part 55 that is disposed on a blade holder 53 and detects level of vibration generated from a blade member 50 that is a vibration source; a rigidity changing means 57 that operates based on the detection result of the vibration detection part 55; and a drive control part 56c of a control means 56 that controls increase and decrease of the rigidity of the blade holder 53 so that the level of the vibration of the blade holder 53 decreases.

Description

  The present invention reduces noise and image degradation caused by vibration between a blade member and an image carrier (photosensitive drum) generated in an electrophotographic copying machine, FAX, printer, etc., and stable cleaning characteristics. The present invention relates to a cleaning device, a process unit, an image forming apparatus, and a color image forming apparatus.

  In an electrophotographic image forming apparatus, toner is supplied onto an electrostatic latent image formed on a photosensitive drum as an image carrier, and the toner image is transferred onto a transfer material to form a printed material. In order to remove the residual toner that could not be transferred from the photosensitive drum, a cleaning device that removes the residual toner by sliding the blade member against the photosensitive drum is widely used.

  A cleaning device using a blade member often presses the blade member against the image carrier at as high a pressure as possible in order to improve adhesion to the image carrier and improve toner removal. In this case, as one of the methods for improving the cleaning action, there is a method of removing the transfer residual toner staying at the contact portion with the image carrier. As a removal method, it is known to activate a compression restoring motion (stick slip) of the blade member caused by a frictional force generated between the blade member and the image carrier. By pressing the blade member against the image carrier, the frequency of stick-slip is increased, and the toner staying with the movement of the blade leaks onto the image carrier, thereby improving the cleaning performance. However, if the pressure is increased too much, the blade member begins to vibrate, and so-called chatter noise or high-frequency abnormal noise may occur due to resonance between the blade member contact edge and the image carrier.

  Further, when the relative vibration between the blade member and the photosensitive drum increases, load fluctuation occurs when the photosensitive drum is driven by friction of the blade member. Therefore, the speed fluctuation of the photosensitive drum increases, and as a result, image deterioration such as banding may occur. Banding refers to an image deterioration phenomenon in which shading corresponding to a speed fluctuation frequency occurs in an output image, and is caused by an increase in speed fluctuation of the photosensitive drum.

  Further, when the blade member vibrates due to resonance, a gap may be generated between the photosensitive drum and the tip of the blade member. In this case, if the gap is larger than the particle diameter of the toner, the toner slips out, causing a cleaning failure.

  Conventionally, Patent Document 1 discloses an invention in which a vibration absorbing member such as an anti-vibration sheet is disposed at a joint portion between a blade member and a blade holder that supports the blade member as a measure against vibration noise in the image forming apparatus. In Patent Document 2, the resonance frequency of the blade member is set so that the vibration frequency generated by stick-slip between the image carrier and the blade member and the resonance frequency of the blade member do not coincide or exist in the vicinity, thereby avoiding vibration amplification due to resonance. Thus, an invention for reducing noise is disclosed. Patent Document 3 discloses an invention that suppresses vibration noise by attaching a weight to a blade holder or a cleaning frame. In Patent Document 4, the blade holder thickness, width, length, etc. are changed so that the blade holder does not resonate with the vibration frequency generated by stick-slip, or the blade member is fixed to the blade holder. An invention has been disclosed in which the vibration frequency is suppressed by changing the natural frequency of the blade member by changing the number, shape, and the like. In Patent Document 5, when a vibration on the blade holder is detected and vibration or noise exceeding a predetermined threshold (60 to 100 dB) is generated, the blade member is moved to move the blade member. And the image bearing member are changed in contact pressure or contact angle, thereby reducing vibration and noise.

  The inventions in Patent Documents 1 to 4 make it difficult for the blade member itself to vibrate itself, but the sliding contact state between the blade member and the image carrier is not fixed and does not change at all. The sliding contact state changes due to a change with time such as a change in humidity or humidity, or a deterioration of the blade member. When the sliding state changes in this way, the resonance frequency of the blade member changes, and the vibration absorbing member may not function effectively, or the non-resonance setting of the blade member may not be useful. If it does so, the effect | action which suppresses a vibration and noise will not work, and there exists a subject that image deterioration and deterioration of cleaning performance arise. In short, the noise countermeasures according to the inventions of Patent Documents 1 to 4 are limited to those that are known at the time of manufacture, and are effective solutions for vibrations and noises that occur later in the operation site due to environmental changes and changes over time. It cannot be a means. For this reason, even if no noise is generated at the time of installation of the image forming apparatus, if noise is generated from the vicinity of the blade member after that, it is necessary to take measures such as replacing the blade member or mounting additional parts for vibration suppression. There was a problem that had to be taken depending on.

  Further, the invention of Patent Document 5 reduces noise by changing the contact pressure or contact angle between the blade member and the image carrier, so even if the noise can be reduced, the optimum setting for toner removal by the blade member May lose the cleaning performance.

  The present invention detects the vibration level using the blade member as a vibration source without changing the sliding contact state between the blade member and the image carrier, and changes the rigidity of the blade holder based on the detection result. It is an object of the present invention to automatically suppress noise.

That is, the following problems are solved by the following inventions 1 to 9.
1. A cleaning device for removing toner remaining on the surface of an image carrier,
A blade member that contacts the surface of the image carrier and removes the toner;
A blade holder for holding the blade member;
Vibration detecting means for detecting a vibration level using the blade member as a vibration source;
Rigidity changing means for changing the rigidity of the blade holder;
Control means for operating the rigidity changing means based on the detection result of the vibration detecting means to increase / decrease the rigidity of the blade holder so that the vibration level of the blade holder decreases;
Having a cleaning device.
2. The control means deactivates the rigidity changing means when a detection result of the vibration detecting means is less than a predetermined vibration level, and operates the rigidity changing means when the detection result is higher than a predetermined vibration level. apparatus.
3. The second cleaning device, wherein a plurality of the vibration detection means are arranged along the longitudinal direction of the blade holder, and the rigidity changing means is operated when a detection result of at least one vibration detection means is equal to or higher than a predetermined vibration level.
4). The rigidity changing means;
A structural member disposed along the blade holder;
A support member that is disposed in a gap between the blade holder and the structural member and is extendable in a direction to increase or decrease the gap;
A restricting member that restrains the blade holder and the intermediate member from each other and restricts a maximum gap between the blade holder and the intermediate member against the extension of the support member;
4. The cleaning device according to 1 to 3, comprising
5. 4. The cleaning device according to 4, wherein a plurality of the support members are arranged in the longitudinal direction of the blade holder.
6). 4. The cleaning device according to 4, wherein the support member is disposed at a position corresponding to a vibration antinode in a predetermined vibration mode of the blade holder.
7). A process unit comprising the cleaning device according to any one of 1 to 6 above.
8). An image forming apparatus comprising the cleaning device according to any one of 1 to 6 above.
9. A color image forming apparatus comprising a plurality of the process units of 7 above.

  The present invention is based on the detection result of the vibration detecting means for detecting the vibration level using the blade member as a vibration source without changing the sliding contact state between the blade member and the image carrier. The rigidity of the blade holder is controlled to increase or decrease so that the vibration level of the blade holder is reduced, so that the vibration generated from the beginning of use of the image forming apparatus as well as the start of use of the image forming apparatus Even if vibration is generated later due to environmental changes or changes over time, the blade holder's natural frequency is prevented from causing self-excited vibration of the blade member by appropriately changing the rigidity of the blade holder in accordance with the vibration. Noise can be generated mainly due to self-excited vibration caused by stick slip of the blade member relative to the image carrier. It can be effectively suppressed. In addition, by suppressing self-excited vibration due to stick slip of the blade member, the behavior of the blade member is stabilized, thereby reducing load fluctuations or speed fluctuations of the image carrier, and improving the cleaning performance and remaining through the blade member. The ratio of toner can be greatly reduced, and high-quality image formation can be achieved by improving development characteristics and transferability. In addition, stabilization of the blade member behavior is effective in reducing blade edge deterioration and aging.

1 is a schematic configuration diagram of an image forming apparatus according to the present invention. It is a schematic block diagram of the process unit which concerns on this invention. It is a schematic block diagram of the cleaning apparatus which concerns on this invention. It is a schematic block diagram of the modification of the cleaning apparatus which concerns on this invention. It is a schematic perspective view of the rigidity change means of the cleaning device according to the present invention. It is a schematic side view of the rigidity changing means of the cleaning device according to the present invention. It is a measurement figure of the vibration level in case the noise noise has generate | occur | produced from the blade member of the cleaning apparatus. It is a measurement figure of the vibration level after driving a rigidity change means. It is a flowchart of the control means which controls a rigidity change means. It is a schematic perspective view which shows the modification of the rigidity change means of the cleaning apparatus which concerns on this invention.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus shown in FIG. 1 includes four process units 1Y, 1C, 1M, and 1Bk as image forming units. The process units 1Y, 1C, 1M, and 1Bk have the same configuration except that they contain toners of different colors of yellow, cyan, magenta, and black corresponding to the color separation components of the color image. Specifically, each of the process units 1Y, 1C, 1M, and 1Bk includes a photosensitive drum 2 as an image carrier, a charging device 3 that charges the surface of the photosensitive drum 2, and a toner image on the photosensitive drum 2. Are provided, a developing device 4 for cleaning the surface of the photosensitive drum 2, a cleaning device 5 for cleaning the surface of the photosensitive drum 2, and a lubricant applying device 6 for applying a lubricant to the surface of the photosensitive drum 2. The process units 1Y, 1C, 1M, and 1Bk are configured to be detachable integrally with the image forming apparatus main body 10. Although the process units have been described in the order of yellow, cyan, magenta, and black, they are not specified in this order, and may be arranged in any order.

  The toner used in this apparatus is a polymerized toner having a spherical shape and a uniform particle size. In the present invention, since a good lubricant coating layer can be formed on the surface of the photoreceptor, the cleaning performance can be improved by stabilizing the behavior of the blade member, thereby greatly reducing the proportion of residual toner that passes through the blade member. In addition, a high quality image can be formed by improving development characteristics and transferability by using a polymer toner having a uniform spherical shape and a small particle diameter.

  A toner bottle 7 filled with toner of each color is provided on the upper portion of the image forming apparatus main body 10. Each color toner in the toner bottle 7 is transferred to a corresponding developing device 4 via a toner transfer pipe (not shown). Under each process unit 1Y, 1C, 1M, 1Bk, an exposure device 8 for exposing the surface of each photosensitive drum 2 is disposed. The exposure device 8 is configured to irradiate each photosensitive drum 2 with laser light. A transfer device 9 is disposed above the process units 1Y, 1C, 1M, and 1Bk. The transfer device 9 has an intermediate transfer belt 11 constituted by an endless belt as a transfer body. The intermediate transfer belt 11 is stretched around a plurality of support rollers 12, 13, 14, and 15. One of the plurality of support rollers 12, 13, 14, 15 is a drive roller, and when the drive roller rotates, the intermediate transfer belt 11 runs in the direction indicated by the arrow in the figure. Yes.

  Four primary transfer rollers 16 as primary transfer means are disposed at positions facing the four photosensitive drums 2. The primary transfer roller 16 is a conductive elastic roller, and is disposed so as to be pressed against the photosensitive drum 2 from the back surface of the intermediate transfer belt 11. The primary transfer roller 16 is applied with a constant current controlled bias as a primary transfer bias. A primary transfer nip is formed at a position where the intermediate transfer belt 11 is sandwiched between each primary transfer roller 16 and each photosensitive drum 2.

  Further, a secondary transfer roller 17 as a secondary transfer unit is in contact with the outer peripheral surface on the right side of the intermediate transfer belt 11 in the drawing. A secondary transfer nip is formed at a position where the intermediate transfer belt 11 is sandwiched between the secondary transfer roller 17 and the support roller 12 facing the secondary transfer roller 17. A power supply for secondary transfer bias is connected to the support roller 12. By applying a voltage having the same polarity as the toner to the support roller 12, a voltage is generated in which the toner travels from the intermediate transfer belt 11 toward the recording paper, so that the toner image can be transferred to the recording paper. The secondary transfer roller 17 is a conductive elastic roller, and a secondary transfer bias power source is connected to the secondary transfer roller 17 so that a transfer bias is applied to the secondary transfer roller 17. There is no problem even if the toner image is secondarily transferred to the recording paper. Further, there is no problem even if one of the transfer bias power supplies is connected to the support roller 12 and the other is connected to the secondary transfer roller 17.

  After the primary transfer process, the toner that could not be transferred remains slightly on the surface of the photosensitive drum 2. The photosensitive drum cleaning device 5 includes a plate-like blade member 50 having elasticity for scraping off the residual toner, and cleans the leading edge of the blade member 50 by sliding it on the surface of the photosensitive drum 2. A belt cleaning device 18 for cleaning the surface of the intermediate transfer belt 11 is disposed on the outer peripheral surface at the left end of the intermediate transfer belt 11 in the drawing.

  A lower part of the image forming apparatus main body 10 is provided with a paper feed tray 19 that stores recording paper P as a recording medium, a paper feed roller 20 that carries the recording paper P out of the paper feed tray 19, and the like. In addition, a conveyance path R for guiding the recording paper P upward from the paper feed tray 19 is formed in the image forming apparatus main body 10. In the transport path R, a pair of registration rollers 21 for measuring the transport timing of the recording paper P is disposed midway from the position where the paper feed roller 20 is disposed to the position where the secondary transfer roller 17 is disposed. Has been. A fixing device 22 for fixing the image on the recording paper P is disposed above the position where the secondary transfer roller 17 is disposed. Further, above the fixing device 22, a pair of paper discharge rollers 24 for discharging the recording paper P to a stock portion 23 formed by denting the upper surface of the image forming apparatus main body 10 is disposed.

The basic operation of the image forming apparatus will be described below with reference to FIG.
When the image forming operation is started, the photosensitive drums 2 of the process units 1Y, 1C, 1M, and 1Bk are rotationally driven clockwise by a driving device (not shown), and the surface of each photosensitive drum 2 is charged by the charging device 3. Are uniformly charged to a predetermined polarity. The surface of each charged photosensitive drum 2 is irradiated with laser light from the exposure device 8, and an electrostatic latent image is formed on the surface of each photosensitive drum 2. At this time, the image information to be exposed to each photosensitive drum 2 is single-color image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. The electrostatic latent image formed on the photosensitive drum 2 in this manner is supplied with toner by each developing device 4 so that the electrostatic latent image is developed (visualized) as a toner image.

  When the driving roller that stretches the intermediate transfer belt 11 is driven to rotate, the intermediate transfer belt 11 travels in the direction indicated by the arrow in the figure. Further, a constant voltage having a polarity opposite to the charging polarity of the toner or a voltage controlled by a constant current is applied to each primary transfer roller 16. As a result, a transfer electric field is formed in the primary transfer nip between each primary transfer roller 16 and each photosensitive drum 2. Then, the toner images of the respective colors formed on the photosensitive drums 2 of the process units 1Y, 1C, 1M, and 1Bk are sequentially superimposed and transferred onto the intermediate transfer belt 11 by the transfer electric field formed in the primary transfer nip. Is done. Thus, the intermediate transfer belt 11 carries a full-color toner image on its surface. Further, a lubricant is applied to the surface of each photoreceptor drum 2 after the transfer of the toner image by the lubricant application device 6, and then the toner remaining on the surface of each photoreceptor drum 2 is removed by the cleaning device 5. The

  When the image forming operation is started, rotation of the paper feed roller 20 is started, and the recording paper P stored in the paper feed tray 19 is sent out to the transport path R. The recording paper P sent to the transport path R is temporarily stopped by the registration roller 21. Thereafter, the driving of the registration roller 21 is resumed, and the recording paper P is placed in the secondary transfer nip between the secondary transfer roller 17 and the intermediate transfer belt 11 in synchronization with the toner image on the intermediate transfer belt 11. send. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 11 is applied to the secondary transfer roller 17, thereby forming a transfer electric field in the secondary transfer nip. When the recording paper P and the toner image on the intermediate transfer belt 11 reach the secondary transfer nip, the toner image on the intermediate transfer belt 11 is transferred onto the recording paper P by the transfer electric field formed in the secondary transfer nip. Are collectively transferred. Further, the toner remaining on the intermediate transfer belt 11 after the transfer is removed by the belt cleaning device 18. The recording paper P onto which the toner image has been transferred is conveyed to the fixing device 22 where the toner image is fixed on the recording paper P. Thereafter, the recording paper P is discharged to the stock unit 23 by the paper discharge roller 24.

  The above description is an image forming operation when a full-color image is formed on a recording sheet. A single-color image can be formed using any one of the four process units 1Y, 1C, 1M, and 1Bk. Two or three process units may be used to form a two or three color image.

  FIG. 2 is a schematic configuration diagram of the process units 1Y, 1C, 1M, and 1Bk. Hereinafter, the configuration of each of the process units 1Y, 1C, 1M, and 1Bk will be described with reference to FIG. As shown in FIG. 2, the charging device 3 includes a contact-type charging roller 30 as a charging member disposed to face the photosensitive drum 2, and a surface on which the charging roller 30 faces the photosensitive drum 2. The charging cleaning roller 31 is disposed so as to be in contact with the opposite surface. The charging roller 30 can be in contact with the photosensitive drum 2 to suppress generation of ozone. The charging roller 30 may be opposed to the photosensitive drum 2 with a small gap, so that dirt such as toner from the photosensitive drum 2 does not easily adhere to the surface of the charging roller 30. It is possible to suppress the dirt and extend its life.

  The charging roller 30 performs AC charging with the AC voltage superimposed on the DC voltage on the photosensitive drum 2. By performing AC charging, the charging current flows sufficiently and the influence of fluctuations in the charging potential due to minute gap fluctuations is suppressed, and the image carrier charging potential is stabilized by uniform charging, resulting in high-quality images. can get.

  The developing device 4 includes a developing case 40 that contains a developer, and a developing roller 41 that is rotatably supported by the developing case 40 and that faces the photosensitive drum 2 through an opening formed in the developing case. A developing blade 42 that regulates the amount of developer on the developing roller 41, and a conveying screw 43 that conveys the developer in the developing case 40 to the developing roller 41. A two-component developer having a toner and a carrier is used as the developer.

  The cleaning device 5 includes a blade member 50 that removes residual toner on the photosensitive drum 2 and a waste toner collecting coil 51 that conveys the removed toner to a waste toner bottle (not shown). In addition, a lubricant application device 6 is disposed on the downstream side of the cleaning device 5 with respect to the rotation direction of the photosensitive drum 2. A spreading blade 35 is disposed further downstream of the lubricant application device 6 with respect to the rotation direction of the photosensitive drum 2.

  Next, operations of the process units 1Y, 1C, 1M, and 1Bk will be described with reference to FIG. When the image forming operation is started, the photosensitive drum 2 is driven to rotate clockwise in FIG. 2, and at this time, the photosensitive drum 2 is charged to a predetermined polarity by the charging roller 30 to which a charging voltage is applied. The charging roller 30 is cleaned by a charging cleaning roller 31. Thereafter, the electrostatic latent image on the photosensitive drum 2 formed by exposure from an exposure device (not shown) moves to a position facing the developing roller 41, and toner is supplied from the developing roller 41 to the electrostatic latent image. . More specifically, after the developer carried on the developing roller 41 that rotates counterclockwise in FIG. 2 is regulated to a predetermined thickness by the developing blade 42, the developing area between the developing roller 41 and the photosensitive drum 2. Here, the toner in the developer is electrostatically transferred to the electrostatic latent image on the photosensitive drum 2, and the electrostatic latent image is visualized as a toner image. Then, the toner image on the photosensitive drum 2 moves to an upper position of the photosensitive drum 2 and is transferred to the intermediate transfer belt here.

  After the toner image is transferred, a lubricant is applied to the surface of the photosensitive drum 2 by the brush roller 61 that rotates clockwise in FIG. Thereafter, the toner remaining on the surface of the photosensitive drum 2 is removed by the blade member 50, and the removed residual toner is conveyed to a waste toner bottle (not shown) by the waste toner collecting coil 51.

  Next, details of the cleaning device 5 of the present invention will be described with reference to FIG. This cleaning device 5 has a blade holder 53 fixed to the housing of the process unit of FIG. The blade member 50 is attached to the blade holder 53. The blade member 50 has a plate shape having elasticity. For example, the blade member 50 has a thickness of 1.0 mm to 2.0 mm and a rebound resilience of 30% to 50%. The contact angle when the blade member 50 is brought into contact with the photosensitive drum 2 is, for example, 7 to 15 °, the contact pressure is 20 N / m to 30 N / m, and the surface friction coefficient of the photosensitive drum is 0.25 to 0. 45. A vibration detection unit 55 serving as a vibration detection unit is disposed on the blade holder 53, and the vibration detection unit 55 measures the vibration level of the blade holder 53 during operation of the image forming apparatus. In FIG. 3, the vibration detection unit 55 is arranged on the blade holder 53, but in addition to the arrangement, the vibration detection unit 55 can be arranged at any place that detects a vibration level using the blade member 50 as a vibration source. . For example, the vibration detection unit 55 can be arranged in the housing of the process unit that supports the blade holder 53 or in the photosensitive drum. Alternatively, the vibration detectors 55 may be distributed at a plurality of locations described above.

  The blade holder 53 can be made of, for example, an ABS resin having a high vibration damping effect, and further can be mixed with a glass-based material or the like as necessary in order to improve vibration damping characteristics. Good. In the present invention, the rigidity changing means 57 is attached to the blade holder 53. FIG. 3 shows only the rigidity changing means 57 conceptually, and specific examples are shown in FIGS.

  The output of the vibration detection unit 55 is input to a control unit 56 that controls to increase or decrease the rigidity of the blade holder 53. The control unit 56 includes an FFT (Fast Fourier Transform) processing unit 56a including an A / D conversion unit, a vibration peak determination unit 56b, and a drive control unit 56c, and the output of the vibration detection unit 55 is A. Discretized by / D conversion and input to the FFT processing unit 56a. The FFT processing unit 56a performs frequency conversion of the obtained vibration data, and noise is generated in the vibration peak determination unit 56b from the FFT processing data. Judge whether or not. When noise is generated, a strong vibration peak PK having a specific frequency is detected on the vibration data subjected to frequency conversion as shown in FIG. 7A. Therefore, when a peak that exceeds a predetermined threshold value (for example, 60 to 100 dB in sound pressure level) of the vibration level set in advance is measured, it is determined that noise has occurred. In that case, the drive controller 56 c drives the stiffness changing means 57 to change the stiffness of the blade holder 53, and changes the natural frequency of the blade holder 53. As a result, the generation of noise mainly due to self-excited vibration due to stick-slip is suppressed, and the peak of the vibration level is eliminated as shown in FIG. 7B.

  As the vibration detection unit 55, a piezoelectric element or the like can be used. A piezoelectric element has a property that a voltage is generated by applying a pressure, or is deformed when a voltage is applied. If it is a piezoelectric element, it is possible to make the detection part relatively small, and there are few restrictions on the installation position, and it can be easily attached to any part of the blade holder 53 using an adhesive such as epoxy resin. . Other than the piezoelectric element, vibration detection using an acceleration sensor or a laser is also possible.

  The attachment position of the vibration detection unit 55 is not particularly limited as long as it can detect a vibration level using the blade member as a vibration source. However, the vibration using the blade member 50 as a vibration source may show a complicated vibration state with respect to the longitudinal direction of the blade member 50 other than the case of simple bending vibration. In such a case, since the vibration state differs depending on the position of the vibration detection unit, there may be a problem that the vibration of the entire blade member 50 cannot be grasped only by the vibration at a certain point.

  For example, when the attachment position of the vibration detection unit 55 corresponds to a “node” of vibration in the vibration mode of the blade holder 53, the detection sensitivity of the vibration detection unit 55 may become extremely insensitive. In order to avoid such a vibration detection failure, a plurality of vibration detection units 55 may be attached in the longitudinal direction of the blade holder 53 as shown in FIG. By attaching a plurality of vibration detection units 55 in this way, even if the attachment position of some vibration detection units 55 corresponds to a “node” of vibration in a specific vibration mode, the remaining vibration detection units 55 can be Since the vibration level using the member 50 as a vibration source is detected normally and with high sensitivity, vibration can be detected with high sensitivity for many vibration modes without lowering the vibration detection sensitivity even in the specific vibration mode described above. Can do.

  The present invention includes a stiffness changing means 57 that changes the stiffness of the blade holder 53 in order to feed back the detection result of the vibration detector 55 to the stiffness change of the blade holder 53. 5 and 6 show a specific configuration example of the rigidity changing means 57, and a structural member 57 a is arranged along the blade holder 53. The structural member 57 a may be disposed on the blade member 50 side, but may be disposed on the opposite side of the blade member 50. Note that the vibration detection unit 55 is omitted in FIGS. 5 and 6.

  The structural member 57a is held by the blade holder 53 via a cylindrical support member 57b, and is connected to the blade holder 53 by a string member 57c so as to regulate the maximum gap between the structural member 57a and the blade holder 53. . Although the support member 57b and the string member 57c are illustrated in a minimum unit for simplification, a plurality of support members 57b and a string member 57c are basically arranged in the longitudinal direction of the blade holder 53 as shown in FIG. By arranging a plurality of support members 57b and string members 57c, the blade holder 53 and the structural member 57a can be morphologically stabilized.

  The upper and lower ends of the support member 57b may be bonded to both the blade holder 53 and the structural member 57a with an adhesive or the like, or one end may be bonded and the other end connected to a mating member with a pivot joint or the like. An actuator is incorporated in the support member 57b so that the clearance between the blade holder 53 and the structural member 57a can be expanded and contracted. The support member 57b expands and contracts in the vertical direction by driving the actuator with a control signal from the drive control unit.

  For example, a piezoelectric element or a stepping motor can be used as the actuator that expands and contracts the support member 57b. The piezoelectric element utilizes the property that a voltage is generated by applying pressure when used in the above-described vibration detection unit 55, but utilizes the property of being deformed (expanded) when a voltage is applied when used as an actuator. That is, a piezoelectric element is disposed at the end or in the middle of the support member 57b, and the support member 57b is expanded or contracted by applying or not applying voltage to the piezoelectric element.

  When a stepping motor is used, the stepping motor is constituted by a combination of a screw and a nut that can be rotated by the motor. Specifically, the stepping motor can be disposed on the structural member 57 a and the nut can be disposed on the blade holder 53. At the time of driving, the nut on the blade holder 53 side is driven up and down by rotating a screw with a stepping motor. Thereby, the clearance gap between the structural member 57a and the blade holder 53 can be changed, and the rigidity as the whole blade holder 53 can be changed.

  As the string member 57c, a cloth string, a metal wire, or the like can be used. The string member 57c is desirably installed as close to the support member 57b as possible in order to prevent the blade holder 53 from being deformed by driving the actuator of the support member 57b.

  The rigidity changing means 57 of the present invention is not limited to the configuration shown in FIGS. For example, an anisotropic member is rotatably arranged in the longitudinal direction of the blade holder 53, and the anisotropic member is rotated by a stepping motor or the like so that the cross-sectional principal axis faces an appropriate direction. The rigidity of the blade holder 53 with respect to the vibration direction may be changed.

  Next, the actual control flow of the control means 56 when the image forming apparatus is operating will be described with reference to FIG. First, the vibration level of the blade holder 53 is measured by the vibration detection unit 55 provided on the blade holder 53 (step S1). The vibration data obtained here is in the time domain, and it is difficult to determine how much vibration is generated if it remains as it is. Therefore, the obtained vibration data is converted into vibration data in the frequency domain by performing FFT conversion by the FFT device (step S2). From this data, the vibration peak determination unit 56b determines whether noise is occurring.

  In order to suppress noise when there is a large vibration peak that exceeds a preset threshold value (for example, 60 to 100 dB in sound pressure level) on vibration data viewed in the frequency domain (step S3), The drive controller 56c operates the rigidity changing means 57 (step S4), and increases the rigidity of the blade holder 53 by a predetermined amount. As a result, the natural frequency of the blade holder 53 changes and noise is suppressed (step S5). When the rigidity of the blade holder 53 is increased by a predetermined amount, the rigidity changing means 57 is once deactivated.

  Next, the vibration level is measured again from step S5 to step S1, and if the noise level is not below the threshold value in steps S2 and S3, the drive control is performed again in step S4 so as to change the rigidity further. I do. As a result, the rigidity changing means 57 is driven again. In this way, peak determination and drive control are repeated until the noise level falls below a certain value. In order to wait for the vibration state of the blade member 50 to be stabilized, a delay timer may be passed before returning from step S5 to step S1.

  When noise is generated, it is known that the blade holder 53 has vibration that strongly includes a specific frequency component. This vibration is considered to be self-excited vibration of the blade holder 53 induced by stick-slip vibration between the blade member 50 and the photosensitive drum 2. Looking at the vibration data in the frequency domain obtained by the FFT apparatus, there is a strong peak of the frequency component corresponding to the natural frequency of the blade holder 53 in a state where noise is generated. The vibration peak determination unit 56b sets a certain threshold for the vibration level in advance, and determines that noise is generated if there is a strong vibration peak that exceeds this threshold.

  When it is determined that noise is generated by the vibration peak determination unit 56b and the rigidity of the blade holder 53 is changed by the drive control unit 56c and the rigidity changing means 57, the natural frequency of the blade holder 53 is shifted accordingly. . Thereby, the excitation of the self-excited vibration of the blade holder 53 due to the vibration of the blade member 50 is suppressed, and the existing vibration peak is reduced. And when a vibration peak becomes below a threshold value, it determines with the vibration peak determination part 56b having eliminated noise.

  During normal operation of the image forming apparatus, the support member 57b is in a contracted state, and the blade holder 53 and the structural member 57a are coupled by a relatively loose constraint. When the vibration detection unit detects the occurrence of a vibration level exceeding a predetermined threshold during the operation of the image forming apparatus, the actuator of the support member 57b is driven by an instruction from the drive control unit 56c, and the support member 57b extends in the vertical direction. . Since the blade holder 53 and the structural member 57a are constrained to each other by the string member 57c, the support member 57b is extended in this state, so that the holding strength by the support member 57b between the blade holder 53 and the structural member 57a is normal. It becomes stronger than the state. Thus, the rigidity of the entire blade holder 53 is increased by the extension of the support member 57b.

  When the number of support members 57b is increased and a plurality of support members 57b are installed in the longitudinal direction of the blade holder 53 as shown in FIG. 9, the amount of change in the holding strength between the blade holder 53 and the structural member 57a can be increased. As a result, the amount of change in rigidity increases and the shift range of the natural frequency also increases, so that it can be expected that the effect of suppressing noise generation will also increase. In FIG. 9, the vibration detection unit 55 is omitted.

  When the frequency of noise to be taken is fixed, it is possible to predict in advance what shape the blade holder 53 will take when noise is generated by performing analysis such as simulation. After making this prediction, the support member 57b may be installed at a portion corresponding to the “antinode” of the vibration mode, that is, at a portion having the largest vibration amplitude. In this case, since deformation of the “antinode” portion of the assumed vibration mode is effectively suppressed, it is possible to exert a high vibration suppression effect with respect to vibration of a specific mode.

  The image forming apparatus provided with the lubricant applying apparatus according to the present invention is not limited to the color image forming apparatus shown in FIG. 1, but may be a monochrome image forming apparatus, a copying machine, a printer, a facsimile, or a complex machine thereof. Good.

1Y, 1C, 1M, 1Bk Process unit 2 Photoconductor drum 3 Charging device 4 Developing device 5 Cleaning device 6 Lubricant coating device 7 Toner bottle 8 Exposure device 9 Transfer device 10 Image forming device main body 11 Intermediate transfer belts 12, 13, 14 , 15 Support roller 16 Primary transfer roller 17 Secondary transfer roller 18 Belt cleaning device 19 Paper feed tray 20 Paper feed roller 21 Registration roller 22 Fixing device 23 Stock unit 24 Paper discharge roller 30 Charging roller 31 Charging cleaning roller 35 Spreading blade 40 Developing case 41 Developing roller 42 Developing blade 43 Conveying screw 50 Blade member 51 Waste toner collection coil 53 Blade holder 55 Vibration detection unit 56 Control unit 56a FFT processing unit 56b Vibration peak determination unit 56c Drive control unit 57 Rigidity change unit 57a Structure Member 57b supporting member 57c cord member 61 brush roller

JP 2009-042496 A JP 2005-215163 A JP 2010-72524 A JP 2007-114606 A JP 2010-145430 A

Claims (9)

A cleaning device for removing toner remaining on the surface of an image carrier,
A blade member that contacts the surface of the image carrier and removes the toner;
A blade holder for holding the blade member;
Vibration detecting means for detecting a vibration level using the blade member as a vibration source;
Rigidity changing means for changing the rigidity of the blade holder;
Control means for operating the rigidity changing means based on the detection result of the vibration detecting means to increase / decrease the rigidity of the blade holder so that the vibration level of the blade holder decreases;
Having a cleaning device.   2. The control unit according to claim 1, wherein the control unit deactivates the rigidity changing unit when a detection result of the vibration detection unit is less than a predetermined vibration level, and operates the stiffness changing unit when the detection result is equal to or higher than a predetermined vibration level. Cleaning device.   The cleaning apparatus according to claim 2, wherein a plurality of the vibration detection means are arranged along the longitudinal direction of the blade holder, and the rigidity changing means is operated when a detection result of at least one vibration detection means is equal to or higher than a predetermined vibration level. The rigidity changing means;
A structural member disposed along the blade holder;
A support member that is disposed in a gap between the blade holder and the structural member and is extendable in a direction to increase or decrease the gap;
A restricting member that restrains the blade holder and the intermediate member from each other and restricts a maximum gap between the blade holder and the intermediate member against the extension of the support member;
The cleaning device according to claim 1, comprising:   The cleaning device according to claim 4, wherein a plurality of the support members are arranged in a longitudinal direction of the blade holder.   The cleaning device according to claim 4, wherein the support member is disposed at a position corresponding to a vibration antinode in a predetermined vibration mode of the blade holder. A process unit comprising the cleaning device according to claim 1. An image forming apparatus comprising the cleaning device according to claim 1. A color image forming apparatus comprising a plurality of process units according to claim 7.

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