JP2013231929A - Blade member, cleaning device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blade member that reliably reduces the occurrence of noise without changing a slide contact state between an object and the blade member, a cleaning device, a process cartridge, and an image forming apparatus.SOLUTION: A blade member 15a is provided with: a blade body 15a1, a leading edge of which contacts an object over a longitudinal direction; a holder member 15a2 that holds the blade body 15a1; vibration detection means 15a3 for detecting the vibration level of the holder member 15a2 having the blade body 15a1 as a vibration source; and rigidity varying means 15a4 and 15a5 for varying the rigidity of the holder member 15a2. The rigidity varying means 15a4 and 15a5 vary the rigidity of the holder member 15a2 so that the vibration level of the holder member 15a2 decreases on the basis of a detection result of the vibration detection means 15a3.

Description

  The present invention relates to a photosensitive member drum installed in an image forming apparatus using an electrophotographic system such as a blade member that abuts on an object traveling in a predetermined direction and a copying machine, a printer, a facsimile, or a composite machine thereof, The present invention relates to a cleaning device that cleans untransferred toner on an image carrier such as a photosensitive belt and an intermediate transfer belt, a process cartridge including the cleaning device, and an image forming apparatus including a blade member.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, a blade member (cleaning blade) is brought into contact with an image carrier (object) such as a photosensitive drum or an intermediate transfer belt and remains on the image carrier. A technique for cleaning untransferred toner is known (for example, see Patent Document 1).

  Specifically, the untransferred toner remaining on the image carrier after the transfer process is removed by a blade member that contacts the image carrier. In this blade member, a blade body made of a rubber material or the like is held in a cantilevered manner on a holder member (blade holder) made of a metal material or the like, and the distal end portion (free end side) of the blade member is long. It is in contact with the image carrier over the direction.

  On the other hand, Patent Document 1 discloses a technique based on noise detected by noise detection means installed in the vicinity of a blade member for the purpose of reducing noise (chattering noise) due to stick-slip of the blade member slidingly contacting the image carrier. A technique for changing the sliding contact state between the image carrier and the blade member by vibrating the blade member with an excitation source is disclosed.

Since the cleaning device of Patent Document 1 described above vibrates the blade member by the vibration source based on the noise detected by the noise detecting means, the effect of reducing the noise caused by stick slip of the blade member can be expected to some extent.
However, when the blade member is vibrated by the vibration source, the sliding contact state between the image carrier (target object) and the blade member also changes. Could occur.

  Such a problem is not limited to the blade member installed in the cleaning device, but is common to all of the blade members that abut against an object traveling in a predetermined direction.

  The present invention has been made in order to solve the above-described problems, and the blade member and the cleaning device can reliably reduce the generation of noise without changing the sliding contact state between the object and the blade member. Another object of the present invention is to provide a process cartridge and an image forming apparatus.

  A blade member according to the first aspect of the present invention is a blade member that abuts on an object traveling in a predetermined direction, and a blade body whose front end abuts on the object in the longitudinal direction; A holder member for holding the blade body, vibration detection means for detecting a vibration level of the holder member using the blade body as a vibration source, and a rigidity variable means for changing the rigidity of the holder member. The variable means changes the rigidity of the holder member so that the vibration level decreases based on the detection result of the vibration detection means.

  In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing device (developing unit) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. It is defined as a unit in which at least one of the cleaning devices (cleaning unit) and the image carrier are integrated and detachably installed on the image forming apparatus main body.

In the present application, the “longitudinal direction” is defined as a direction orthogonal to the traveling direction of the object. Accordingly, when the object is an image carrier, the “longitudinal direction” is the same direction as the rotation axis direction (or main scanning direction) of the image carrier.
Further, the “short direction” is defined as a direction orthogonal to the “longitudinal direction”.

  In the present invention, the rigidity of the holder member is varied by the stiffness varying means so that the vibration level is lowered based on the detection result of the vibration detecting means for detecting the vibration level of the holder member. Accordingly, it is possible to provide a blade member, a cleaning device, a process cartridge, and an image forming apparatus in which generation of noise is reliably reduced without changing the sliding contact state between the object and the blade member.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows an image creation part. It is a perspective view which shows a blade member. It is a flowchart which shows the rigidity variable control in a blade member. It is a graph which shows the vibration level which arises in a blade member. It is a perspective view which shows the blade member as a modification.

Embodiments Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
The image forming apparatus 1 according to the present embodiment is a tandem color image forming apparatus in which process cartridges 10Y, 10M, 10C, and 10BK as a plurality of image forming units are arranged in parallel so as to face the intermediate transfer belt 17. .

  In FIG. 1, 1 is an apparatus main body of a color copying machine as an image forming apparatus, 3 is a document conveying unit that conveys a document to a document reading unit 4, 4 is a document reading unit that reads image information of a document, and 6 is input image information. A writing unit (exposure unit) that emits laser light based on the above, 7 is a paper feeding unit that accommodates a recording medium P such as transfer paper, and 10Y, 10M, 10C, and 10BK are colors (yellow, magenta, cyan, and black). A process cartridge as a corresponding image forming unit, 17 is an intermediate transfer belt on which toner images of a plurality of colors are transferred in an overlapping manner, and 18 is a secondary transfer that transfers a toner image formed on the intermediate transfer belt 17 to a recording medium P. A roller, 20 a fixing unit for fixing an unfixed image on the recording medium P, and 28 a toner for each color is supplied to the developing unit of each process cartridge (image forming unit) 10Y, 10M, 10C, 10BK. Toner container of the eye, showing the.

Here, each of the process cartridges 10Y, 10M, 10C, and 10BK (image forming unit) includes a photosensitive drum 11 (object) as an image carrier, a charging unit 12, a developing unit 13 (developing device), and a cleaning unit, respectively. 15 (cleaning device) and a lubricant supply unit 16 (lubricant supply device) are integrated (see FIG. 2). The process cartridges 10Y, 10M, 10C, and 10BK are replaced with the apparatus main body 1 when the lifetime is reached.
A toner image of each color (yellow, magenta, cyan, black) is formed on the photosensitive drum 11 (image carrier) in each of the process cartridges 10Y, 10M, 10C, and 10BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, the document is transported from the document table by the transport rollers of the document transport unit 3 and placed on the contact glass of the document reading unit 4. Then, the document reading unit 4 optically reads the image information of the document placed on the contact glass.
Specifically, the document reading unit 4 scans an image of a document on the contact glass while irradiating light emitted from an illumination lamp. Then, the light reflected from the original is imaged on the color sensor via the mirror group and the lens. The color image information of the original is read for each color separation light of RGB (red, green, blue) by the color sensor, and then converted into an electrical image signal. Further, an image processing unit (not shown) performs color conversion processing, color correction processing, spatial frequency correction processing, and the like on the basis of RGB color separation image signals, so that yellow, magenta, cyan, and black are processed. Get color image information.

  Then, image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 6. Then, laser light (exposure light) based on the image information of each color is emitted from the writing unit 6 toward the photosensitive drums 11 of the corresponding process cartridges 10Y, 10M, 10C, and 10BK, respectively.

On the other hand, the four photosensitive drums 11 rotate in the clockwise direction in the figure. First, the surface of the photosensitive drum 11 is uniformly charged at a position facing the charging roller 12a (charging unit 12) (this is a charging process). Thus, a charged potential is formed on the photosensitive drum 11. Thereafter, the surface of the charged photosensitive drum 11 reaches the irradiation position of each laser beam.
In the writing unit 6, laser light corresponding to the image signal is emitted from the light source corresponding to each color. Although not shown, the laser light is incident on the polygon mirror and reflected, and then passes through a plurality of lenses. The laser light after passing through the plurality of lenses passes through different optical paths for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  Laser light corresponding to the yellow component is irradiated onto the surface of the photosensitive drum 11 of the first process cartridge 10Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotational axis direction (main scanning direction) of the photosensitive drum 11 by a polygon mirror (not shown) that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11 after being charged by the charging roller 12a.

  Similarly, the cyan component laser light is applied to the surface of the photosensitive drum 11 of the second process cartridge 10 </ b> C from the left side of the sheet, thereby forming an electrostatic latent image of the cyan component. The laser beam corresponding to the magenta component is irradiated onto the surface of the photosensitive drum 11 of the third process cartridge 10M from the left side of the paper, and an electrostatic latent image corresponding to the magenta component is formed. The black component laser light is applied to the surface of the photosensitive drum 11 of the process cartridge 10BK (black image forming unit), which is fourth from the left side of the drawing (the most downstream side with respect to the traveling direction of the intermediate transfer belt 17). Thus, an electrostatic latent image of the black component is formed.

Thereafter, the surface of the photosensitive drum 11 on which the electrostatic latent image of each color is formed reaches a position facing the developing unit 13. Then, each color toner is supplied from each developing unit 13 onto the photosensitive drum 11, and the latent image on the photosensitive drum 11 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 11 after the development process reaches a position facing the intermediate transfer belt 17. Here, a primary transfer roller 14 is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 17. Then, at the position of the primary transfer roller 14, the toner images of the respective colors formed on the photosensitive drum 11 are sequentially transferred onto the intermediate transfer belt 17 (first transfer process).

Then, the surface of the photosensitive drum 11 after the first transfer process reaches a position facing the cleaning unit 15. The untransferred toner remaining on the photosensitive drum 11 is collected by the cleaning unit 15 (this is a cleaning process).
Thereafter, the surface of the photoconductive drum 11 sequentially passes through the position of the lubricant supply unit 16 and the position of the charge eliminating unit (not shown), and a series of image forming processes on the photoconductive drum 11 is completed.

On the other hand, the surface of the intermediate transfer belt 17 on which the images of the respective colors on the photosensitive drum 11 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the secondary transfer roller 18. Then, the full color image on the intermediate transfer belt 17 is secondarily transferred onto the recording medium P at the position of the secondary transfer roller 18 (second transfer step).
Thereafter, the surface of the intermediate transfer belt 17 reaches the position of an intermediate transfer belt cleaning unit (not shown). The untransferred toner on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit, and a series of transfer processes on the intermediate transfer belt 17 is completed.

Here, the recording medium P at the position of the secondary transfer roller 18 is conveyed from the paper supply unit 7 via the conveyance guide, the registration roller 19 and the like.
Specifically, the transfer paper P fed by the paper feed roller 8 from the paper feed unit 7 that stores the recording medium P is guided to the registration roller 19 after passing through the conveyance guide. The recording medium P that has reached the registration roller 19 is conveyed toward the position of the secondary transfer roller 18 in synchronization with the toner image on the intermediate transfer belt 17.

Thereafter, the recording medium P on which the full-color image is transferred is guided to the fixing unit 20. In the fixing unit 20, the color image is fixed on the recording medium P at the nip between the fixing roller and the pressure roller.
The recording medium P after the fixing step is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 29 and then stacked on the paper discharge unit 5 to complete a series of image forming processes.

Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIG.
FIG. 2 is a block diagram showing a process cartridge 10BK (monochrome process cartridge) as a black image forming unit. The monochrome process cartridge 10BK and the color process cartridges 10Y, 10M, and 10C are configured by substantially the same constituent members except that the color of the toner used in the image forming process is different. The illustration and description of the process cartridges 10Y, 10M, and 10C are omitted as appropriate.

  As shown in FIG. 2, the process cartridge 10BK includes a photosensitive drum 11 as an image carrier, a charging unit 12 (charging roller) for charging the photosensitive drum 11, and a static electricity formed on the photosensitive drum 11. A developing unit 13 that develops the electrostatic latent image, a cleaning unit 15 that collects untransferred toner on the photosensitive drum 11, and a lubricant supply unit 16 that supplies a lubricant to the photosensitive drum 11 are provided in the case. It is housed in one piece.

Here, the photosensitive drum 11 as an image bearing member is a negatively charged organic photosensitive member, and a photosensitive layer or the like is provided on a drum-shaped conductive support.
Although not shown, the photosensitive drum 11 has an undercoat layer that is an insulating layer, a charge generation layer and a charge transport layer as a photosensitive layer, and a protective layer (surface layer) in this order on a conductive support as a base layer. Are stacked.
As the conductive support (base layer) of the photosensitive drum 11, a conductive material having a volume resistance of 10 ¹⁰ Ωcm or less can be used.

The charging unit 12 (charging roller) is a roller member formed by covering an outer periphery of a conductive metal core with a medium-resistance elastic layer, and is located downstream of the lubricant supply unit 16 in the rotation direction of the photosensitive drum 11. It is arranged. Further, the charging unit 12 (charging roller) is disposed so as to come into contact with the photosensitive drum 11 in order to reduce the generation of ozone.
A predetermined voltage (a voltage obtained by superimposing an AC voltage on a DC voltage) is applied to the charging unit 12 from a power supply unit (not shown), thereby uniformly charging the surface of the photosensitive drum 11 in contact therewith. To do.

  The developing unit (developing device) 13 mainly includes a developing roller 13a that faces the photosensitive drum 11, a first transport screw 13b1 that faces the developing roller 13a, and a first transport screw 13b1 that faces the first transport screw 13b1 via a partition member. It is comprised by the 2 conveyance screw 13b2 and the doctor blade 13c facing the developing roller 13a. The developing roller 13a includes a magnet that is fixed inside and forms a magnetic pole on the peripheral surface of the roller, and a sleeve that rotates around the magnet. A plurality of magnetic poles are formed on the developing roller 13a (sleeve) by the magnet, and the developer is carried on the developing roller 13a.

In the developing unit 13, a two-component developer composed of a carrier and a toner is accommodated.
As the toner, spherical toner having a circularity of 0.98 or more is used to improve the image quality. The “circularity” is an average circularity measured by a flow type particle image analyzer “FPIA-2000” (manufactured by Toa Medical Electronics Co., Ltd.). Specifically, 0.1 to 0.5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. Further, about 0.1 to 0.5 g of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the dispersion liquid concentration is set to 3000 to 10000 / μl in the above-described analyzer. Then, the shape and distribution of the toner are measured.

As the spherical toner, it is possible to use an irregularly shaped toner (pulverized toner) whose shape is distorted by a pulverization method that has been widely used so far, which is spheroidized by heat treatment or the like, or a toner manufactured by a polymerization method. it can.
When such a spherical toner is used, conventionally, there is a case in which a slight gap between the cleaning blade 15a and the photosensitive drum 11 enters the gap and eventually passes through the gap, resulting in poor cleaning. However, in the present embodiment, a lubricant is applied to the surface of the photosensitive drum 11 by the lubricant supply unit 16 to improve the toner peelability (removability) on the photosensitive drum 11, so that a cleaning failure occurs. Is suppressed.

The cleaning unit 15 is disposed upstream of the lubricant supply unit 16 in the rotation direction of the photosensitive drum 11. The cleaning unit 15 includes a cleaning blade 15a (blade member) that contacts the photosensitive drum 11 (object), and toner collected in the cleaning unit 15 as waste toner in a waste toner collection container (not shown). A transfer coil 15b and the like that transfer toward the camera are installed.
The cleaning blade 15a as a blade member is mainly composed of a blade body 15a1 (blade) made of a rubber material such as urethane rubber, and a holder member 15a2 (blade) formed of sheet metal and holding the blade body 15a1. Holder). The blade body 15a1 of the cleaning blade 15a is in contact with the surface of the photosensitive drum 11 at a predetermined angle and a predetermined pressure. As a result, deposits such as untransferred toner adhering to the photosensitive drum 11 are mechanically scraped and collected in the cleaning unit 15. Here, examples of the deposit that adheres to the photosensitive drum 11 include untransferred toner, paper dust generated from the recording medium P (paper), and a discharge product generated on the photosensitive drum 11 when discharged by the charging roller 12a. And additives added to the toner.
In the present embodiment, the cleaning blade 15a as a blade member is configured such that its rigidity is varied according to the vibration level, which will be described in detail later.

The lubricant supply unit 16 is provided with a solid lubricant 16b, a lubricant supply roller 16a (brush roller) that is in sliding contact with the photosensitive drum 11 and the solid lubricant 16b, and a solid lubricant 16b directed toward the lubricant supply roller 16a. A compression spring 16c that is energized, a thinning blade 16d that thins the lubricant supplied onto the photosensitive drum 11 by the lubricant supply roller 16a, and the like. The thinning blade 16d is configured to abut against the photosensitive drum 11 in the counter direction at a position downstream of the lubricant supply roller 16a in the rotation direction of the photosensitive drum 11.
The lubricant supply unit 16 configured as described above supplies the thinned lubricant on the photosensitive drum 11.

The image forming process described above will be described in more detail with reference to FIG.
The developing roller 13a rotates in the arrow direction (counterclockwise direction) in FIG. The developer in the developing unit 13 is replenished from the toner container 28 by a toner replenishing unit (not shown) by the rotation of the first transport screw 13b1 and the second transport screw 13b2 that are disposed so as to interpose a partition member therebetween. The toner circulates in the longitudinal direction while being agitated and mixed with the toner (the direction perpendicular to the paper surface of FIG. 2).

  The toner that is frictionally charged and adsorbed on the carrier is carried on the developing roller 13a together with the carrier. The developer carried on the developing roller 13a then reaches the position of the doctor blade 13c. The developer on the developing roller 13a is adjusted to an appropriate amount at the position of the doctor blade 13c and then reaches a position facing the photosensitive drum 11 (development region).

  Thereafter, in the developing region, the toner in the developer adheres to the electrostatic latent image formed on the surface of the photosensitive drum 11. Specifically, the latent image potential (exposure potential) of the image portion irradiated with the laser beam L and the electric field formed by the potential difference (development potential) between the development bias applied to the developing roller 13a cause the toner to become a latent image. (Toner image is formed).

  Thereafter, most of the toner adhering to the photosensitive drum 11 in the developing process is transferred onto the intermediate transfer belt 17. The untransferred toner remaining on the photosensitive drum 11 is collected in the cleaning unit 15 by the cleaning blade 15a.

Here, although not shown in the figure, a toner replenishing unit provided in the apparatus main body 1 has a bottle-shaped toner container 28 configured to be replaceable, and holds and rotates the toner container 28, and a new one in the developing unit 13. And a toner hopper for replenishing toner. Also, a new toner (any one of yellow, magenta, cyan, and black) is accommodated in the toner container 28. In addition, a spiral protrusion is formed on the inner peripheral surface of the toner container 28 (toner bottle).
The new toner in the toner container 28 is appropriately supplied from the toner supply port into the developing unit 13 as the toner in the developing unit 13 (existing toner) is consumed. Although illustration is omitted, the consumption of toner in the developing unit 13 is indirectly caused by a reflection type photosensor facing the photosensitive drum 11 and a magnetic sensor installed below the second conveying screw 23b2 of the developing unit 13. Or detected directly.

Hereinafter, the configuration and operation of the characteristic cleaning blade 15a (blade member) in the cleaning device 15 according to the present embodiment will be described in detail.
As described above, the cleaning blade 15a as a blade member contacts the photosensitive drum 11 as an object that travels (rotates) in a predetermined direction and remains on the photosensitive drum 11 (image carrier). Untransferred toner is removed.
Referring to FIG. 3, the cleaning blade 15a (blade member) in the present embodiment includes a vibration detection unit 15a3 as vibration detection means, a variable stiffness, in addition to the blade body 15a1 and the holder member 15a2 described above. A piezoelectric element 15a4 and an auxiliary member 15a5 that function as means are installed.

Here, the blade body 15a1 has a tip end (free end side) in contact with the photosensitive drum 11 in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 2 and the direction of the double arrow in FIG. 3). At the same time, the root portion is fixed and held by the holder member 15a2. The blade body 15a1 is made of a rubber material such as urethane rubber, and has a substantially plate shape.
The holder member 15a2 is formed of a substantially plate-like sheet metal, and the blade body 15a1 is fixed and held by adhesion or the like. The holder member 15a2 is fixed and held in the case of the cleaning device 15.
The vibration detection unit 15a3 as the vibration detection means is a piezoelectric sensor (piezoelectric vibration sensor), and is installed on the surface of the holder member 15a2 via an adhesive such as epoxy resin. The vibration detection unit 15a3 detects the vibration level of the holder member 15a2 using the blade body 15a1 as a vibration source. The vibration detection unit 15a3 includes a control unit 40 (FFT processing unit 41, vibration peak determination unit 42, voltage control) of the apparatus body 1. Part 43 etc.). As the vibration detection unit 15a3 (vibration detection means), an acceleration sensor, a vibration detection sensor using a laser, or the like can be used instead of the piezoelectric sensor.

Further, the cleaning blade 15a (blade member) in the present embodiment is provided with stiffness varying means 15a4 and 15a5 that vary the stiffness of the holder member 15a2. Then, the stiffness varying means 15a4, 15a5 varies the stiffness of the holder member 15a2 so that the vibration level of the holder member 15a2 is lowered based on the detection result of the vibration detecting unit 15a3 (vibration detecting means).
Specifically, the stiffness variable means mainly includes a piezoelectric element 15a4 attached to the holder member 15a2, and an auxiliary member 15a5 attached to the piezoelectric element 15a4 so as to sandwich the piezoelectric element 15a4 between the holder member 15a2. It consists of The piezoelectric element 15a4 is formed in a substantially rectangular plate shape, is installed in a range extending in the longitudinal direction with respect to the holder member 15a2, and is connected to the voltage control unit 43 (power supply unit) at both ends in the longitudinal direction. A terminal portion 15a41 is formed. The auxiliary member 15a5 (auxiliary plate) is a substantially rectangular plate-like member formed of a resin material or a metal material having a relatively high mechanical strength, and is piezoelectric in the range extending in the longitudinal direction with respect to the holder member 15a2. It is installed so as to cover the element 15a4.
The stiffness variable means expands and contracts the piezoelectric element 15a4 by applying a voltage to the piezoelectric element 15a4 based on the detection result of the vibration detecting unit 15a3 (vibration detecting means), and the holder member 15a2 is not deformed by the auxiliary member 15a5. While doing so, the rigidity of the holder member 15a2 is varied.

This will be described in more detail below.
While the image forming apparatus 1 is in operation, the vibration level of the holder member 15a2 is measured by the vibration detection unit 15a3 (vibration detection unit) installed on the holder member 15a2. The output of the vibration detection unit 15a3 is input to the control unit 40 that controls increase / decrease of the rigidity of the holder body 15a2. The control unit 40 includes an FFT processing unit 41 including an A / D conversion unit (a Fast Fourier Transform processing unit that performs fast Fourier transform), a vibration peak determination unit 42, a voltage And a control unit 43.

  The output of the vibration detection unit 15a3 is discretized by A / D conversion and input to the FFT processing unit 41, and the FFT processing unit 41 performs frequency conversion of vibration data. Then, from the processing data of the FFT processing unit 41, the vibration peak determination unit 42 determines whether or not vibration has occurred. Specifically, when noise is generated, a specific vibration peak having a high frequency is detected in the vibration data subjected to frequency conversion. When a vibration peak that exceeds a preset vibration level threshold (for example, a sound pressure level of 60 to 100 dB) is detected, it is determined that noise has occurred. In that case, a voltage is applied from the voltage control unit 43 to the piezoelectric element 15a4 on the holder member 15a2. Here, the piezoelectric element 15a4 is an element that generates a voltage when pressure is applied, and conversely expands and contracts when a voltage is applied.

When a voltage is applied to the piezoelectric element 15a4, the piezoelectric element 15a4 is deformed so as to expand (or contract) in the longitudinal direction and contract (or expand) in the thickness direction according to the magnitude of the voltage. Occurs. The voltage application at this time is performed quasi-statically, and the expansion and contraction of the piezoelectric element 15a4 is performed constantly. Here, since the auxiliary member 15a5 is attached on the piezoelectric element 15a4 so that the piezoelectric element 15a4 is sandwiched between the blade member 15a2 and the piezoelectric element 15a4 expands and contracts, the holder member 15a2 has a macro level. No deformation will occur. Therefore, there is almost no problem that the sliding state of the cleaning blade 15a changes with respect to the photosensitive drum 11 as the object.
That is, by applying a voltage to the piezoelectric element 15a4, the rigidity of the holder member 15a2 as a whole changes in a state where macro deformation of the holder member 15a2 is prevented, and the natural frequency thereof changes (holder) The resonance of the member 15a2 does not occur). This reduces the generation of noise mainly due to self-excited vibration in the cleaning blade 15a.
The expansion / contraction amount of the piezoelectric element 15a4 can be changed by changing the voltage applied to the piezoelectric element 15a4, whereby the rigidity (the magnitude of rigidity) of the holder member 15a2 can also be changed (increase / decrease). .

FIG. 4 is a flowchart showing the stiffness variable control in the above-described cleaning blade 15a.
As shown in FIG. 4, first, the vibration level of the holder member 15a2 is measured by the vibration detector 15a3 (step S1). The vibration data obtained here is in the time domain, and it is difficult to determine how much vibration is generated as it is. Therefore, the obtained vibration data is converted into vibration data in the frequency domain by performing FFT conversion by the FFT processing unit 41 (step S2). And from this vibration data, it is determined in the vibration peak determination part 42 whether the noise has generate | occur | produced. That is, in the vibration data in the frequency domain, it is determined whether there is a large vibration peak that exceeds a preset threshold value (step S3).
As a result, when it is determined in step S3 that there is a large vibration peak that exceeds the threshold, a voltage controlled by the voltage control unit 43 is applied to the piezoelectric element 15a4 in order to suppress noise (step S3). As a result, the piezoelectric element 15a4 expands and contracts to change the rigidity of the holder member 15a2 (step S5). As a result, the natural frequency of the holder member 15a2 changes, and noise generated in the cleaning blade 15a is reduced.
Further, returning from step S5 to step S1, the flow of steps S1 to S3 is repeated, and if the vibration level is not below the threshold value, the flow of steps S4 to S5 is performed so as to further change the rigidity of the holder member 15a2. Execute.
In this way, by repeating the peak determination and the voltage control until the vibration level falls below the threshold value, the noise generated in the cleaning blade 15a is surely reduced.
In addition, in order to wait for the vibration state of the holder member 15a2 to be stabilized, the control flow may be configured to pass through a delay timer before returning from step S5 to step S1.

FIG. 5 is a graph showing the vibration level generated by the cleaning blade.
As shown in FIG. 5A, in the conventional apparatus, when noise is generated at the position of the cleaning blade, vibration that strongly includes a specific frequency component is generated in the holder member. This vibration is considered to be self-excited vibration of the holder member induced by stick-slip vibration between the cleaning blade and the photosensitive drum. When looking at the vibration data in the frequency domain obtained by the FFT processing unit, there is a strong peak of the frequency component corresponding to the natural frequency of the holder member when noise is generated.
For this reason, in the present embodiment, a threshold for the vibration level is set in the vibration peak determination unit 42 in advance, and it is determined that noise is generated when there is a strong vibration peak that exceeds this threshold. Yes. Specifically, in the present embodiment, as shown in FIG. 5B, when the vibration peak determination unit 42 determines that noise is generated, the voltage control unit 43 applies a voltage to the piezoelectric element 15a4. As a result, the rigidity of the holder member 15a2 is changed, and the natural frequency of the holder member 15a2 is shifted accordingly. Thereby, the self-excited vibration of the holder member 15a2 due to the vibration of the cleaning blade 15a is suppressed, and a strong vibration peak as shown in FIG. 5A is reduced. And when a vibration peak becomes below a threshold value, it is determined by the vibration peak determination part 42 that there was no noise.

In the present embodiment, the piezoelectric element 15a4 and the auxiliary member 15a5 are installed in a range extending in the longitudinal direction with respect to the holder member 15a2, but the installation form of the piezoelectric element 15a4 and the auxiliary member 15a5 is limited to this. For example, various forms as shown in FIGS. 6A to 6D can be adopted.
Specifically, in the case of FIG. 6A, the piezoelectric element 15a4 and the auxiliary member 15a5 are each in a range extending in the lateral direction with respect to the holder member 15a2, and are installed at both ends in the longitudinal direction. When noise is generated in the cleaning blade 15a, depending on the mode of the vibration mode, the noise suppression effect may be enhanced by attaching the piezoelectric element 15a4 and the auxiliary member 15a5 in the short direction of the holder member 15a2. In such a case, this configuration is useful.
6B, the piezoelectric element 15a4 and the auxiliary member 15a5 are respectively installed on the front and back surfaces (both sides) of the holder member 15a2. In such a case, since the piezoelectric element 15a4 can be expanded and contracted on the front and back surfaces (both sides) of the holder member 15a2, a large rigidity change can be brought about with respect to the holder member 15a2.
In FIG. 6C, a plurality of piezoelectric elements 15a4 and auxiliary members 15a5 are installed with respect to the holder member 15a2. In such a case, voltage control is separately performed on the piezoelectric element 15a4 divided into a plurality of parts (in the example of FIG. 6C, it is divided into three parts in the longitudinal direction). Therefore, since the amount of expansion and contraction and the timing of expansion and contraction can be varied for each position, the rigidity of the holder member 15a2 can be flexibly changed as compared with the case where the expansion and contraction is uniformly performed in the longitudinal direction.
In FIG. 6D, the piezoelectric element 15a4 and the auxiliary member 15a5 are installed at the antinode position in the vibration mode of the holder member 15a2. When the frequency of sound generated as noise in the cleaning blade 15a is known, the vibration mode of the holder member 15a2 at the time of noise generation can be estimated by performing simulation such as eigenvalue analysis. And, by estimating a large deformation portion corresponding to the “antinode” of the vibration mode and attaching the piezoelectric element 15a4 to that portion, it is possible to exert a high noise suppression effect on the vibration mode generated as noise. it can.

  As described above, according to the present embodiment, the piezoelectric element and 15a4 are configured so that the vibration level is lowered based on the detection result of the vibration detection unit 15a3 (vibration detection means) that detects the vibration level of the holder member 15a2. The rigidity of the holder member 15a2 is varied by the auxiliary member 15a5 (rigidity varying means). Thereby, the generation of noise can be reliably reduced without changing the sliding contact state between the photosensitive drum 11 (object) and the cleaning blade 15a (blade member).

In this embodiment, the process cartridges 10Y and 10M are integrated by integrating the respective parts (the photosensitive drum 11, the charging part 12, the developing part 13, the cleaning part 15, and the lubricant supplying part 16) in the image forming part. 10C and 10BK are configured to reduce the size of the image forming unit and improve maintenance workability.
On the other hand, the cleaning device 15 (cleaning unit) may be configured so as to be replaceable in the apparatus main body 1 without being a component of the process cartridge. In such a case, the same effect as that of the present embodiment can be obtained.
In the present embodiment, the present invention is applied to the image forming apparatus equipped with the two-component developing type developing device 13 using the two-component developer. However, the one-component developing type using the one-component developer is used. Of course, the present invention can also be applied to an image forming apparatus in which the developing device 13 is mounted.

  In the present embodiment, the present invention is applied to the cleaning device 15 that cleans untransferred toner remaining on the photosensitive drum 11. In contrast, the present invention can naturally be applied to a cleaning device that cleans untransferred toner remaining on the photosensitive belt. The present invention can also be applied to a cleaning device that cleans untransferred toner remaining on an image carrier (intermediate transfer member) such as an intermediate transfer belt or an intermediate transfer drum. For example, the cleaning blade in the cleaning device (intermediate transfer cleaning device) for cleaning untransferred toner on the intermediate transfer belt 17 shown in FIG. 1 is configured in the same manner as the cleaning blade 15a shown in FIG. The same effect can be obtained.

  In the present embodiment, the present invention is applied to the cleaning device 15 provided with the blade body 15a1 formed of a rubber material. On the other hand, the present invention can also be applied to the cleaning device 15 in which the blade body 15a1 formed of a material other than a rubber material (for example, a leaf spring material or the like) is installed. In such a case, the same effect as in the present embodiment can be obtained.

  In the present embodiment, the present invention is applied to the cleaning blade 15a as a blade member that abuts on the photosensitive drum 11 as an object that travels in a predetermined direction. However, the application of the present invention is not limited to this. The present invention can be applied to all of the blade members that come into contact with an object that travels in a predetermined direction. In such a case, the same effect as in the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus body (apparatus body),
11 Photosensitive drum (image carrier),
15 Cleaning unit (cleaning device),
15a Cleaning blade (blade member),
15a1 blade body,
15a2 holder member,
15a3 vibration detection unit (vibration detection means),
15a4 piezoelectric element (rigidity variable means),
15a5 Auxiliary member (rigidity variable means).

JP 2009-169277 A

Claims (10)

A blade member that contacts an object traveling in a predetermined direction,
A blade body whose tip is in contact with the object in the longitudinal direction;
A holder member for holding the blade body;
Vibration detecting means for detecting a vibration level of the holder member using the blade body as a vibration source;
Stiffness varying means for varying the stiffness of the holder member;
With
The blade member characterized in that the rigidity variable means changes the rigidity of the holder member so that the vibration level is lowered based on a detection result of the vibration detection means. The stiffness varying means is
A piezoelectric element attached to the holder member, and an auxiliary member attached to the piezoelectric element so as to sandwich the piezoelectric element between the holder member,
The piezoelectric element is expanded and contracted by applying a voltage to the piezoelectric element based on the detection result of the vibration detecting means, and the rigidity of the holder member is varied while the holder member is not deformed by the auxiliary member. The blade member according to claim 1.   The blade member according to claim 2, wherein the piezoelectric element and the auxiliary member are installed in a range extending in a longitudinal direction with respect to the holder member.   The blade member according to claim 2, wherein the piezoelectric element and the auxiliary member are installed in a range extending in a short direction with respect to the holder member.   The blade member according to any one of claims 2 to 4, wherein the piezoelectric element and the auxiliary member are respectively installed on the front and back surfaces of the holder member.   The blade member according to claim 2, wherein a plurality of the piezoelectric elements and the auxiliary members are provided.   The blade member according to any one of claims 2 to 6, wherein the piezoelectric element and the auxiliary member are disposed at an antinode position in a vibration mode of the holder member. A cleaning device for cleaning untransferred toner remaining on an image carrier,
The object is the image carrier,
A cleaning device comprising the blade member according to claim 1. A process cartridge that is detachably attached to the image forming apparatus main body,
9. A process cartridge in which the cleaning device according to claim 8 and the image carrier are integrated.   An image forming apparatus comprising the blade member according to claim 1.

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