JP2005234044A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus contrived to make the restraint of the exchange frequency of a brush compatible with the appropriate supply of lubricant to an image carrier. <P>SOLUTION: The image forming apparatus is equipped with a cleaning part for scraping off residue remaining on the surface of the image carrier after a toner image on the image carrier is transferred to a body to be transferred, the solid lubricant to be applied to the surface of the image carrier, the brush arranged on a more upstream side in the rotating direction of the image carrier than the cleaning part and applying the lubricant to the surface of the image carrier by rotating in a state where it comes into contact with the solid lubricant, a flicking member for flicking off an adhesive matter adhering to the brush by coming into contact with the brush, and a control part for controlling the contact state of the flicking member with the brush. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image composed of a fixed toner image on a recording medium.

  Conventionally, an electrostatic latent image formed on an image carrier is developed by using a developing device that holds a developer containing toner to form a toner image on the surface of the image carrier, and the toner image is transferred. In an image forming apparatus of a type that is transferred onto a transfer medium by a container and is finally fixed on a recording medium, the residue remaining on the surface of the photoconductor after the transfer of the toner image onto an intermediate transfer belt or recording paper In some cases, a cleaning member such as a cleaning blade is in contact with the photosensitive member for cleaning the toner.

  However, in an image forming apparatus that performs cleaning by bringing a cleaning member into contact with the photosensitive member, there has been a problem that wear of the photosensitive member is intensified due to friction generated between the cleaning member and the photosensitive member. .

  Therefore, a rotating brush that rubs while rotating on the surface of the photoconductor after the transfer is provided on the upstream side of the cleaning member and on the downstream side of the transfer unit in the rotation direction of the photoconductor. A proposal has been made to assist cleaning by disturbing the transfer residual toner remaining on the surface of the photoconductor after the toner image is transferred (see, for example, Patent Document 1).

  Further, the proposed image forming apparatus is provided with a flicking member that comes into contact with the bristles of the rotating brush, and the flicking member is rotated by the rotating brush rubbing the surface of the photoreceptor after the transfer. The residue that has moved to the brush is knocked down. As a result, the residue once collected from the surface of the photoconductor is prevented from adhering to the surface of the photoconductor again.

  According to this proposal, the conventional cleaning performance can be maintained even if the contact pressure of the cleaning member to the photoconductor is weakened in order to suppress intensification of wear of the photoconductor.

  The proposed image forming apparatus is designed to minimize the burden on the rotating brush by controlling the contact degree of the flicking member to the rotating brush according to the image density of the toner image formed on the photosensitive member. It has also been made.

  In addition, as a means for suppressing intensification of wear of the photosensitive member, a rotating brush for supplying a lubricant to the surface of the photosensitive member after transfer of the toner image is provided upstream of the cleaning member in the rotational direction of the photosensitive member. Has been proposed.

  FIG. 1 is a diagram showing a rotating brush for applying a lubricant.

  FIG. 1 shows a photoconductor 101, a charger 102 for applying a predetermined charge to the photoconductor 101, and the surface exposed to form an electrostatic latent image on the surface of the photoconductor 101 to which a predetermined charge is applied. An exposure device 103, a developing roll 104 for developing an electrostatic latent image formed on the surface of the photoconductor 101, an intermediate transfer belt 109 on which a toner image formed on the photoconductor is transferred by a transfer device 105, and a photosensitive member. A rotating brush 106 that supplies lubricant from the solid lubricant 110 to the surface of the body and a blade 108b that scrapes the residue remaining on the surface of the photoreceptor 101 after the transfer of the toner image are shown. FIG. 1 also shows a state in which the solid lubricant 110 is disposed at a position in contact with the rotating brush 106 and a state in which the blade 108b is attached to the base plate 108a.

  By the way, even in an image forming apparatus that applies a lubricant to the photosensitive member 101 as shown in FIG. 1, when the lubricant is applied to the photosensitive member 101 by the rotating brush 106, the residue remaining on the surface of the photosensitive member 101. Moves to the rotating brush 106, and the residue transferred to the rotating brush 106 adheres to the contact surface 110a of the solid lubricant 110 that contacts the rotating brush 106 and solidifies to cover the contact surface 110a. As a result, it is known that the application of the lubricant to the photosensitive member 101 is interrupted.

Therefore, in the above proposal, in order to prevent this, a flicking member 117 for knocking down the external additive transferred to the rotating brush 116 is provided.
JP-A-8-15024

  However, since the flicking member 107 made of a material harder than the bristles of the rotating brush 106 deforms or damages the bristles of the rotating brush 106, it is necessary to properly apply the lubricant to the photosensitive member 101. Has a problem that the rotating brush 106 must be frequently replaced.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus that is devised to achieve both suppression of brush replacement frequency and appropriate application of a lubricant to an image carrier.

In order to achieve the above object, an image forming apparatus of the present invention comprises:
After a predetermined charge is applied by a charger to the surface of the image carrier that is rotationally driven in a predetermined direction, an electrostatic latent image is formed on the surface of the image carrier based on image information, and a developer containing toner is held. The electrostatic latent image is developed with toner using a developing device to form a toner image on the surface of the image bearing member, and the toner image is transferred to a transfer target by a transfer device, and finally a recording medium In an image forming apparatus that forms an image composed of a fixed toner image on a recording medium by fixing the image on the recording medium.
The image carrier is disposed upstream of the charger in the rotational direction of the image carrier and downstream of the transfer unit in the rotational direction of the image carrier. A cleaning unit that scrapes off the residue remaining on the surface of the image carrier after being transferred,
A solid lubricant applied to the surface of the image carrier;
It is disposed upstream of the cleaning unit in the rotation direction of the image carrier and downstream of the transfer unit in the rotation direction of the image carrier, and rotates in contact with the solid lubricant. A brush for applying a lubricant to the surface of the image carrier;
A flicking member that knocks off deposits adhered to the brush by contacting the brush;
And a controller that controls a contact state of the flicking member with the brush.

  In the image forming apparatus of the present invention, the residue that has been transferred to the brush for applying the lubricant onto the image carrier due to rubbing with the image carrier and that may interfere with the application of the lubricant to the image carrier is struck. The contact state of the flickering member to be dropped with respect to the brush can be controlled by the control unit. As a result, for example, it is possible to reduce the burden on the brush while suppressing the adhesion of the residue to the lubricant depending on whether the amount of the residue remaining on the image carrier can be predicted to be large or not. As described above, the contact state of the flicking member with the brush can be changed. Therefore, according to the image forming apparatus of the present invention, it is possible to achieve both suppression of the replacement frequency of the brush and appropriate supply of the lubricant to the image carrier.

  Here, a rotating portion that holds the solid lubricant and is rotatably supported via a rotating shaft that is parallel to the brush, and a moment generating portion that generates a moment around the rotating shaft. It is preferable to provide a support member for bringing the solid lubricant held in the rotating portion into contact with the brush by the moment generated in the moment generating portion.

  If it does in this way, it can contribute to the stable supply of the lubricant to an image carrier on composition.

  Moreover, it is preferable that the said control part controls the amount of biting of the said flicking member to the said brush.

Further, the image density that the image forming apparatus predicts based on the image information, the image density that represents the ratio of the area of the electrostatic latent image formed on the basis of the image information that is subjected to toner adhesion by development. With a predictor,
The control unit has a preset threshold value, and increases the bite amount when the image density predicted by the image density prediction unit is less than the threshold value than when the image density is equal to or more than the threshold value. Preferably there is.

  Among the contaminants that are more likely to adhere to the lubricant than the toner, those that are charged with a polarity opposite to that of the toner are more likely to adhere electrostatically to the region other than the region where the toner image is formed on the image carrier. For this reason, the lower the image density at the time of toner image formation, the greater the amount of contaminants that electrostatically adhere to the image carrier. Therefore, if there are more contaminants on the image carrier that are more likely to adhere to the lubricant than the toner and thus more likely to prevent the lubricant from being applied to the image carrier than the toner, Since it is considered that there is a large amount in the residue even after the transfer, the external additive from the brush can be struck efficiently by controlling the amount of biting in this way. Thereby, it is possible to effectively achieve both suppression of the replacement frequency of the brush and appropriate supply of the lubricant to the image carrier.

Alternatively, a counter that counts the number of recording media onto which the toner image is finally transferred is provided.
The developer holds the developer containing a magnetic carrier covered with a coating material having a stronger adhesion to the solid lubricant than the toner while stirring and develops the electrostatic latent image with the toner. Because
The control unit has a second threshold value set in advance, and when the count value in the counter is less than the second threshold value, the amount of biting is more than in the case where the count value is greater than or equal to the second threshold value. It is also a preferred embodiment that it is increased.

  Since the coating material peeled off from the magnetic carrier by the contact between the toner and the magnetic carrier by stirring is gradually discharged from the developer every time a toner image is formed, the amount of the coating material in the developer is It decreases as the cumulative number of recording media onto which toner images are transferred increases. As a result, when the cumulative number of recording media onto which the toner image is finally transferred is large or small, it is considered that the amount of contaminants contained in the residue is larger when the cumulative number is small. By controlling the amount of biting in this way, it is possible to effectively achieve both suppression of the brush replacement frequency and appropriate supply of the lubricant to the image carrier.

  Here, it is preferable that the flicking member has a plate shape, and both end portions have a shape wider than the central portion.

  On the surface of the image carrier, since the frequency of toner image formation to the end is low, the end tends to be a region other than the region where the toner image is formed on the image carrier. For this reason, among the contaminants that are more likely to adhere to the lubricant than the toner, those that are charged with a polarity opposite to that of the toner may adhere to the end portion at a higher density than the region other than the end portion. Therefore, the amount of flickering member biting into both end portions of the brush is made larger than that in the central portion, so that both the suppression of the replacement frequency of the brush and the appropriate supply of the lubricant to the image carrier can be achieved. Can be achieved more effectively.

  According to the image forming apparatus of the present invention, it is possible to achieve both suppression of the replacement frequency of the brush and appropriate supply of the lubricant to the image carrier.

  Hereinafter, embodiments of the image forming apparatus of the present invention will be described.

  FIG. 2 is a schematic configuration diagram of a main part of an embodiment of the image forming apparatus of the present invention.

  As shown in FIG. 2, the printer 1 according to the present embodiment includes four image forming units 10Y, 10M, 10C, and 10K. Each image forming unit has a photosensitive element that rotates in the direction of arrow A. Bodies 11Y, 11M, 11C, 11K, chargers 13Y, 13M, 13C, 13K, exposure devices 14Y, 14M, 14C, 14K, developing rolls 12Y, 12M, 12C, 12K, primary transfer rolls 20Y, 20M, 20C, 20K, Photosensitive member maintenance units 15Y, 15M, 15C, and 15K in which a rotating brush for supplying lubricant, a cleaning blade, a flicking member, and the like are arranged, and a control unit 16Y that controls the amount of biting of the flicking member into the rotating brush. , 16M, 16C, and 16K. The printer 1 can perform full-color printing, and the symbols Y, M, C, and K added to the end of each of the above components are yellow, magenta, cyan, and black images, respectively. It is a component for formation.

  The printer 1 also includes an intermediate transfer belt 30 that circulates in the direction of arrow B, a secondary transfer roll 40, a tension roller 31, a light sensor 32 for monitoring the passage of paper, and image information in each image forming unit. Is also provided.

  The central control unit 50 has a built-in counter 51 that counts the number of sheets that have passed through the place where the optical sensor 32 is provided in accordance with a transmission signal from the optical sensor 32, and has been input from the outside. The image information is decomposed into image information for each color and transmitted to the exposure units 14Y, 14M, 14C, and 14K, and the image density information can be transmitted to the control units 16Y, 16M, 16C, and 16K of the image forming units. ing. In addition, from the central control unit 50, communication lines for issuing instructions to the respective components of the respective image forming units are actually extended to the respective components. However, in order to prevent the complexity of the drawing, The illustration here is limited to a part of them.

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

  In the printer 1, first, toner image formation by the yellow image forming unit 10 </ b> Y is started, and a predetermined charge is applied to the surface of the photoreceptor 11 </ b> Y rotating in the direction of arrow A by the charger 13 </ b> Y. Next, in accordance with the image information transmitted from the central control unit 50, exposure light corresponding to the yellow image generated by the exposure device 14Y is irradiated on the surface of the photoreceptor 11Y, and an electrostatic latent image is formed. . The electrostatic latent image is developed with yellow toner by the developing roller 12Y to form a yellow toner image on the photoreceptor 11Y. The toner image is transferred to the intermediate transfer belt 30 by the primary transfer roll 20Y.

  Here, the printer 1 uses a developer including toner and a magnetic carrier coated with a coating material for ensuring the charging characteristics of the toner, and uses an electrostatic latent image formed on the photoconductor according to image information. The image is developed (visualized). The printer 1 is of a type in which only the toner is filled after the developer cartridge filled with such a developer is loaded in the apparatus. In the printer 1, the toner and the magnetic carrier are used. The toner is negatively charged and the external additive of the magnetic carrier is positively charged.

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

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

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

  FIG. 3 is an enlarged view of the yellow image forming unit shown in FIG.

  The photoreceptor maintenance unit 15Y, which is a component of the yellow image forming unit 10Y shown in FIG. 3, includes a housing 150Y, a lubricant supply mechanism 155Y including a solid lubricant 1554Y, and a bristle portion 1521Y extending radially about the rotation shaft 1522Y. , A stepping motor 154Y for causing the flicking member 156Y to bite into the rotating brush 152Y, and a blade 151Y made of urethane rubber.

  The lubricant supply mechanism 155Y includes a rotation shaft 1551Y, a rotation arm 1552Y, a weight 1553Y, a solid lubricant 1554Y, and a rotatable cam 1555Y whose shaft is directly connected to a rotation shaft of a motor (not shown). Yes.

  The solid lubricant 1554Y contains zinc stearate as a main component, and is attached to a rotating arm 1552Y that can rotate around a rotating shaft 1551Y.

  The rotating arm 1552Y is supported by a rotating shaft 1555Y and supported by a cam 1555Y that rotates as a motor (not shown) rotates. Therefore, when the cam 1555Y rotates, the rotating brush 152Y and the solid lubricant 1554Y repeats contact and separation, and the rotating arm 1552Y has its own weight due to the solid lubricant 1554Y and the weight of the weight 1553Y attached to the opposite side of the solid lubricant 1554Y across the rotating arm 1552Y. A moment in the direction in which the solid lubricant 1554Y is pressed against the rotary brush 152 shown in FIG. Therefore, in the printer 1, the amount of lubricant supplied to the photoreceptor 11Y can be controlled by changing the weight of the weight.

  Further, the stepping motor 154Y is connected to the control unit 16Y provided outside the housing 150Y of the photoconductor maintenance unit 15Y by an electric wire 1541Y.

  As described above, the printer 1 uses a developer including a toner and a magnetic carrier coated with a resin for ensuring the charging performance of the toner. And may be peeled off from the magnetic carrier due to contact with the toner, and may adhere to a region on the photoreceptor other than the region where the electrostatic latent image is formed during toner development.

  FIG. 4 is an external perspective view of the stepping motor and the flicking member shown in FIG.

  The flicking member 156Y shown in FIG. 4 is provided with a shaft 1561Y that passes through the flicking member 156Y in the longitudinal direction thereof, and this shaft 1561Y is directly connected to the rotating shaft of the stepping motor 154Y. Note that both ends of the rotating shaft 1522Y of the rotating brush 152Y and the end of the flicking member shaft 1561Y opposite to the motor are rotatably supported by a support member (not shown).

  FIG. 5 is an enlarged view of the stepping motor, the flicking member, and the control unit shown in FIG.

  The rotation of the stepping motor 154Y shown in FIG. 5 is controlled by the voltage applied from the control unit 16Y, and the flickering member 156Y also rotates and bites into the rotating brush 152Y as the stepping motor 154Y rotates. .

  FIG. 5B shows a posture in which the flicking member 156Y is completely separated from the rotating brush 152Y (0 °) and a posture in which the amount of biting into the rotating brush 152Y is the smallest (45 °) and the amount in which the amount of biting is the largest. It is shown that control is possible with a total of five postures including four postures up to (60 °).

  Hereinafter, control of the amount of biting of the flicking member 156Y into the rotating brush 152Y in the printer 1 will be described.

  In this printer 1, when the image density in image formation is higher than a predetermined value, the coating resin peeled off from the magnetic carrier is relatively difficult to adhere to the surface of the photoreceptor 11Y. When the amount of adhesion is small and the image density in image formation is lower than a predetermined value, the coating resin peeled off from the magnetic carrier is relatively easily adhered to the surface of the photoreceptor 11Y. As the amount of contaminants deposited increases, and as the number of printed sheets increases, the amount of coating resin peeled from the magnetic carrier in the developer decreases, so the total number of printed sheets is the predetermined number. In the case of exceeding the value, the amount of the coating resin that has adhered to the surface of the photoconductor 11Y and peeled off from the magnetic carrier is reduced. And controls the amount of biting flicking member 156Y to Y. Here, when the inclination of the flicking member 156Y is 45 °, 50 °, 55 °, and 60 °, the amount of biting into the rotating brush 152Y is 1.0 mm, 1.2 mm, 1.4 mm, and 1. It is 5 mm.

  FIG. 6 is a flowchart of a routine that is started when the printer of the present embodiment is turned on.

  FIG. 6 shows a flow of the operation of the control unit 16Y of the yellow image forming unit 10Y after the printer 1 is turned on. In step S1, the amount of biting of the flicking member 156Y into the rotating brush 152Y is completely different. An instruction is given so that there is no angle 0 °. In step S2, a count value representing the total number of prints up to the present is acquired from a counter 51 built in the central control unit 50 shown in FIG. Thereafter, the process proceeds to step S3, where it is determined whether or not the count value acquired in step S5 represents a preset value, for example, the number of printed sheets of 40,000 sheets or more, and 40,000 sheets or more are printed. If it is determined, the process proceeds to step S4 to determine whether or not image formation is performed. This determination is performed by detecting whether or not the central control unit 50 issues a drive instruction to the photoconductor 11Y, the charger 13Y, and the developing roll 12Y. If it is determined in step S4 that image formation has not yet been performed, in step S5, an instruction is issued so that the flicking member 156Y has an angle of 0 ° so as not to place a burden on the rotating brush 152Y until image formation. . Then return to 4. If it is determined in step S4 that image formation is to be performed, the process proceeds to step S6. In step S6, image density information for image formation to be performed from now is obtained from the central control unit 50. Then, it progresses to step S7 and it is determined whether the acquired image density is below a predetermined value. If it is determined in step S7 that the angle is equal to or smaller than the predetermined value, the process proceeds to step S8, where an instruction is given to set the angle to 50 ° in order to set the amount of biting of the flicking member 156Y to 1.2, and then the process returns to step S2. . If it is determined in step S7 that the image density exceeds the predetermined value, the process proceeds to step S9, where an instruction is given to set the angle to 45 ° in order to set the amount of biting of the flicking member 156Y to 1.0, and then step S2 Return to.

  On the other hand, if it is determined in step S3 that the count value is less than 40,000, the process proceeds to step S10. If it is determined in step S10 that image formation has not yet been performed, the flicking member 156Y is determined in step S11. Is given an angle of 0 °. If it is determined in step S10 that image formation is to be performed, the process proceeds to step S12. In step S12, image density information for image formation to be performed is acquired. Then, it progresses to step S13 and it is determined whether the acquired image density is below a predetermined value. If it is determined in step S13 that the angle is equal to or less than the predetermined value, the process proceeds to step S14, and an instruction is given to set the angle to 60 ° in order to set the biting amount of the flicking member 156Y to 1.5 mm, and then the process returns to step S2. . If it is determined in step S13 that the image density exceeds the predetermined value, the process proceeds to step S15, and an instruction is given to set the angle to 50 ° in order to set the biting amount of the flicking member 156Y to 1.2 mm, and then step S2 Return to.

  In the printer 1, the amount of biting of the flicking member 156Y into the rotating brush 152Y is controlled by rotating the flicking member 156Y by the stepping motor 154Y. However, as shown in FIGS. 7 and 8, the flicking member 156Y is controlled. The amount of biting may be controlled by operating the.

  7 and 8 are diagrams showing another mode of the biting amount control.

  FIG. 7 shows a mode in which the flicking 156Y is moved in the vertical direction and bites into the rotating brush 152Y, and FIG. 8 shows a mode in which the flicking 156Y is moved in the horizontal direction and bites into the rotating brush 152Y. Yes.

  Hereinafter, examples and comparative examples performed using the printer 1 of the present embodiment will be described with reference to Tables 1 and 2 below. In the image carrier, which is an effect of the image forming apparatus of the present invention. The compatibility between the suppression of the replacement frequency of the brush to which the lubricant is applied and the appropriate supply of the lubricant to the image carrier is determined by the results of comprehensive evaluation shown in Table 2.

  Table 1 shows the amount of biting of the flicking member 156Y into the rotating brush 152Y in the case of image formation and image non-formation in each of less than 40,000 prints from the initial stage and more than 40,000 prints in the latter half. Are shown for each aspect from Example 1 to Comparative Example 3, and at the time of image formation, “low image density” in which the image density is lower than a predetermined value and “image density is higher than a predetermined value”. The amount of biting in each case of “high image density” is shown.

In this printer 1, the rotating brush 152Y has a beltlon B12N (manufactured by Kanebo Co., Ltd., fiber thickness 6 denier, brush hair density 5 × 10 ³ / inch ² , hair length 6.5 mm (adhesive layer). The solid lubricant 1554Y is obtained by melting zinc stearate and molding it into a bar shape of 5 mm × 5 mm × 320 mm. The blade 151Y has a blade hardness of 87 and a free length of 9 mm, and is set to have a blade linear pressure of 2.6 gf / mm, a setting angle of 23 °, and a blade cleaning angle of 12.6 °. A negatively chargeable material having a shape factor (SF1) of 132 having a mean particle size of 35 μm and a carrier having a mean particle size of 35 μm is used as the carrier coating material. A resin obtained by random copolymerization of isobutyl methacrylate / methyl methacrylic acid / perfluorooctyl ethyl methacrylate is used.

  In Table 2 shown below, measurement results and evaluations from Example 1 to Comparative Example 3 are shown.

  Here, regarding the wear of the photoconductor 11Y, the film thickness of the photoconductor 11Y before printing and after the completion of printing of a total of 80,000 sheets is measured with an eddy current film thickness meter, and the difference is calculated. 10-point average roughness (Ra) measurement with a surface roughness meter (Surfcom 1400A manufactured by Tokyo Seimitsu Co., Ltd.) was carried out, and the judgment criteria were ○ (Rz 3.0 μm or less), Δ (3.0 <Rz <3. 5 μm) and x (Rz> 3.5 μm). The degree of solidification of the surface of the solid lubricant 1554Y is determined by sensory evaluation by visual observation, and the judgment criteria are ○ (no solidification at all), Δ (some solidification), and × (obviously solidified on the surface). . Evaluation of the uniformity of the halftone image is made by sensory evaluation by visual observation of the print image, and the judgment criteria are ○ (no problem), Δ (slightly splattered), and x (splattered frequently). The brush sag was evaluated using the tip force as an index. . The 'sagging' of the rotating brush roller was measured and evaluated before and after the running test using a brush tip force measuring device manufactured independently. The brush tip force measuring device uses a load cell to detect a downward force applied to the tip of a flat plate bitten by a rotating brush (this is assumed to be a brush tip force). Further, the measurement was performed under the fixed condition that the amount of biting into the flat brush was 1.0 mm, the rotation speed of the brush was 230 rpm, and the width of the flat plate (with respect to the brush rotation axis direction) was 100 mm. Based on the above, the judgment criteria for 'fallback' are as follows: ○ when the tip force change is less than 15 g, △ when the tip force change is 15 g or more and 20 g or less, and when the tip force change exceeds 20 g Is marked with x. This change in tip force is calculated by subtracting the tip force after the running test from the tip force before the running test.

  From Comparative Example 2 and Comparative Example 3 shown in Table 2, it can be read that there is an effect by changing the amount of biting according to the image density. From Example 2 and Comparative Example 3, the effect of reducing the amount of biting after the number of printed sheets exceeded 40,000 was read. From Example 2 and Comparative Example 1, the number of printed sheets exceeded 40,000. In addition, when the image formation is performed at a low image density, the effect of increasing the image encroachment amount is read more than when the image formation is performed at a low image density. Furthermore, it can be seen from Example 1 and Example 3 that the amount of biting in the case of low image density is more effective until the number of printed sheets exceeds 40,000.

  As described above, when the image density at the time of image formation is lower than the predetermined value, and when the total number of printed sheets is less than the predetermined value, the image density at the time of image formation is higher than the predetermined value, Also, the amount of biting of the flicking member 156Y into the rotating brush 152Y is increased compared to the case where the total number of printed sheets is equal to or greater than a predetermined value, thereby suppressing the frequency of brush replacement and the appropriate amount of lubricant on the image carrier. The balance with supply has been achieved.

  In the present embodiment, the case where the amount of biting is controlled according to whether the image density is higher than a predetermined value and whether the total number of printed sheets is larger than the predetermined number has been described as an example. A plurality of these predetermined values and predetermined number of sheets may be set and controlled.

  In the present embodiment, the case where the control is performed based on the total number of printed sheets is described as an example. However, the present invention is not limited to this, and the total number of times the photosensitive member 11Y is charged by the charger 13Y. The control may be performed based on the number of prints reflected, such as the total number of rotations of the photoconductor 11Y and the total number of rotations of the developing roll 14Y.

  Furthermore, in this embodiment, the case where the lubricant supply mechanism 155Y is provided and the solid lubricant 1554Y is pressed against the rotating brush 52Y is described as an example. However, moment generation in the lubricant supply mechanism 155Y is not a weight. For example, a torsion spring attached to the rotating shaft 1551Y may be used, and even if the lubricant supply mechanism 155Y is omitted, the basic effect of the present invention is not reduced. Absent. Here, in this embodiment, the case where zinc stearate is used as a main component as an example of the type of solid lubricant 1554Y has been described as an example. However, fatty acid metal salts such as magnesium stearate, fluorine such as PTFE, etc. A resin may be used.

Furthermore, in the present embodiment, the case where a flicking member whose both ends are wider than the center is described as an example. However, even if both ends have the same width as the center, the basic of the present invention is described. The effect is not reduced. Here, the material of the brush fibers is preferably nylon, acrylic or polypropylene, and among these, nylon is particularly preferable because of its excellent long-term stability. The fiber thickness of the brush surface is preferably 2 to 10 denier, more preferably 3 to 10 denier. By setting the fiber thickness within the above range, the solid lubricant 1554Y is scraped off and applied to the photoreceptor 11Y. The fiber length of the brush surface (* not including the raised adhesive layer thickness) is preferably 2.5 mm to 7 mm, more preferably 3 mm to 6.5 mm. By setting the fiber length within the above range, the solid lubricant 1554Y is scraped off and applied to the photoreceptor 11Y. The rotational speed of the rotary brush 152Y is desirably controlled in a range where the speed ratio with respect to the photoreceptor 11Y is 0.5 to 1.5. If the peripheral speed ratio is lower than 0.5, toner may be packed between the rotating brush 152Y and the photoconductor 11Y, which may cause cleaning failure and toner fixation to the photoconductor. If the peripheral speed ratio is greater than 1.5, the photoreceptor may be damaged by brush rubbing. The fiber density on the brush surface is preferably 15 × 10 ^{3 to} 120 × 10 ³ fibers / inch ² (23.4 to 186 fibers / mm ² ), more preferably 20 × 10 ^{3 to} 60 × 10 ³ fibers / inch ^2. it is (31.0 to 93.0 this / ^mm2). By setting the fiber density within the above range, it is possible to apply a uniform lubricant over a long period of time. The method of pressing the solid lubricant 1554Y against the brush is the simplest, but the initial load of the solid lubricant 1554Y is preferably 12 gf to 60 gf (118 mN to 588 mN), more preferably 15 gf to 40 gf (147 mN to 392 mN). ). Setting the load on the brush within the above range is preferable because an appropriate amount of lubricant can be supplied over a long period of time.

It is a figure which shows the rotating brush for apply | coating a lubricant. 1 is a schematic configuration diagram of a main part of an embodiment of an image forming apparatus of the present invention. FIG. 3 is an enlarged view of a yellow image forming unit shown in FIG. 2. It is an external appearance perspective view of a stepping motor and a flicking member shown in FIG. FIG. 4 is an enlarged view of a stepping motor, a flicking member, and a control unit shown in FIG. 3. 4 is a flowchart of a routine that is started when the printer of the present embodiment is turned on. It is a figure which shows another aspect of biting-in amount control. It is a figure which shows another aspect of biting-in amount control.

Explanation of symbols

1 Printer 10Y, 10M, 10C, 10K Image forming unit 11Y, 11M, 11C, 11K Photoconductor 12Y, 12M, 12C, 12K Developing roll 13Y, 13M, 13C, 13K Charger 14Y, 14M, 14C, 14K Exposure unit 15Y, 15M, 15C, 15K Photoconductor maintenance unit 16Y, 16M, 16C, 16K Control unit 150Y Housing 151Y Blade 152Y Rotating brush 154Y Stepping motor 155Y Lubricant supply mechanism 156Y Flicking member 30 Intermediate transfer belt 31 Tension roller 32 Optical sensor 40 Secondary transfer Roll 50 Central control unit 51 Counter 200 Paper

Claims (3)

After applying a predetermined charge to the surface of the image carrier that is driven to rotate in a predetermined direction by a charger, an electrostatic latent image is formed on the surface of the image carrier based on image information and charged to a predetermined polarity. The electrostatic latent image is developed by attaching the toner in the developer to the electrostatic latent image using a developing device that holds the developer containing the toner, and a toner image is formed on the surface of the image carrier. In an image forming apparatus that forms an image composed of a fixed toner image on the recording medium by forming, transferring the toner image to a transfer medium by a transfer device, and finally fixing the image on the recording medium.
The image bearing member is disposed upstream of the charging device in the rotational direction of the image carrier and downstream of the transfer device in the rotational direction of the image carrier, and the toner image on the image carrier is transferred to the transferred material. A cleaning unit that scrapes off the residue remaining on the surface of the image carrier after being transferred, by scraping the surface with the surface;
A solid lubricant applied to the surface of the image carrier;
An area that is disposed upstream of the cleaning unit in the rotational direction of the image carrier and downstream of the transfer unit in the rotational direction of the image carrier, and is in contact with the surface of the image carrier; A brush that applies the lubricant to the surface of the image carrier by rotating through two regions, the region in contact with the lubricant, and
A flicking member that knocks off deposits adhered to the brush by contacting the brush;
An image forming apparatus comprising: a control unit that controls a contact state of the flicking member with the brush.   The image forming apparatus according to claim 1, wherein the control unit controls an amount of biting of the flicking member into the brush. The image density that the image forming apparatus further predicts based on the image information an image density that represents a ratio of an area of the electrostatic latent image formed on the basis of the image information to which the toner is attached by development. With a predictor,
The control unit has a threshold value related to the image density, and when the image density predicted by the image density prediction unit is less than the threshold value, the bite amount is larger than when the image density is equal to or more than the threshold value. The image forming apparatus according to claim 2, wherein the image forming apparatus increases the image quality.

Images