JP2016014864A - Rubbing member, protective layer forming device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubbing member for leveling a protective agent enabling acquisition of high-quality images stably for a long period in an image forming apparatus.SOLUTION: A protective agent leveling member 72 (part of rubbing member) includes: a contact plate 72a that has a band plate shape extending substantially parallel to the width direction of the outer peripheral surface 3a (image forming surface) of a photoreceptor drum 3, and has its long end edge in contact with the outer peripheral surface 3a (image forming surface) over the entire width in the width direction; and a support part 72b supports the contact plate 72a while capable of changing the attitude of contact (state of contact) with the outer peripheral surface 3a (image forming surface) of the photoreceptor drum 3.

Description

  The present invention relates to a rubbing member for rubbing an image forming surface of a photosensitive drum or an intermediate transfer belt of an image forming apparatus for cleaning or forming a protective layer, and a protective layer forming apparatus provided with such a rubbing member, And an image forming apparatus.

  In an image forming apparatus using a so-called electrophotographic process, an electric charge is applied to the outer peripheral surface of a photosensitive drum by discharge to charge the outer peripheral surface, and the charged outer peripheral surface is exposed to form an electrostatic latent image. The electrostatic latent image is developed with toner, and the formed toner image is directly transferred onto a sheet or transferred via an intermediate transfer belt, and then fixed and discharged. Deposits such as untransferred toner may remain on the image forming surface such as the photosensitive drum after transfer and the outer peripheral surface of the intermediate transfer belt. For this reason, the image forming surface is cleaned by a cleaning member that rubs the image forming surface so that they do not adversely affect the next image formation, and is prepared for the next image formation.

  Here, when the outer peripheral surface of the photosensitive drum is charged, electrical stress is applied to the photosensitive drum, and the state of the outer peripheral surface of the photosensitive drum may be changed greatly. This electrical stress is particularly prominent in the contact charging method and the proximity charging method with a discharge phenomenon in the vicinity of the outer peripheral surface of the photosensitive drum. In these charging methods, many active species and reaction products are generated on the outer peripheral surface of the photosensitive drum, and active species and reaction products generated in the atmosphere in the discharge area are adsorbed on the outer peripheral surface of the photosensitive drum. There are things to do. When such adsorption occurs, the adhesion force of the outer peripheral surface of the photosensitive drum is increased, the cleaning performance by the cleaning member is lowered, and foreign matter adhesion (filming) is likely to occur. In particular, in the charging method in which the AC component is superimposed on the DC component, the influence on the material in the surface layer of the photosensitive drum is large, and the molecular weight is decreased by the resin molecular chain breakage, the degree of entanglement of the polymer chain is decreased, the resin is evaporated, etc. Chemical degradation may occur. Under such circumstances, when the outer peripheral surface of the photosensitive drum is mechanically rubbed by the cleaning member, the wear of the photosensitive drum is further promoted.

  As a cleaning member, a cleaning blade made of an elastic material such as rubber or a cleaning brush formed of a fiber made of synthetic resin in a brush shape is rubbed against the outer peripheral surface of the photosensitive drum to remove deposits from the outer peripheral surface of the photosensitive drum. What is removed is generally known. However, such a cleaning member also wears over time. The wear of the cleaning member causes a decrease in cleaning performance, and as a result, adhesion of foreign matter (filming) to the outer peripheral surface of the photosensitive drum is likely to occur.

  Therefore, in order to prevent chemical deterioration of the photosensitive drum, and to reduce frictional resistance acting between the photosensitive drum and the cleaning member to prevent abrasion due to rubbing of the photosensitive drum and the cleaning member. A technique such as applying a protective agent to the outer peripheral surface of the body drum is employed. If the amount of the protective agent applied to the outer peripheral surface of the photosensitive drum is too small, uneven coating may occur, resulting in poor cleaning in a portion where the protective agent is not sufficiently applied, and wear of the cleaning member progressing. There is a fear. On the other hand, if the amount of the protective agent is too large, a space for arranging the protective agent becomes large due to, for example, an increase in the size of the solid protective agent, which may increase the size of the machine. In addition, the protective agent may contaminate the surface of the charging roller that is close to or in contact with the outer peripheral surface of the photosensitive drum, so that uniform charging may not be performed and a streak-like image defect may be caused. Therefore, it is important to apply an appropriate amount of protective agent to the outer peripheral surface of the photosensitive drum.

  Therefore, in order to apply an appropriate amount of the protective agent to the outer peripheral surface of the photosensitive drum, for example, it has been proposed to define the density of the fibers of the brush roller to which the protective agent is applied (for example, Patent Document 1, 2). In these Patent Documents 1 and 2, in addition to the regulation of the fiber density of the brush roller, a pressurizing member that pressurizes the solid protective agent on the brush roller side is provided to regulate the pressure, or the photosensitive drum of the brush roller Proposals have also been made to regulate the amount of biting into the outer peripheral surface. Further, in order to optimize the coating amount of the protective agent on the outer peripheral surface of the photosensitive drum, a method for controlling the coating amount of the protective agent based on image data information has been proposed (for example, see Patent Document 3). ).

  Incidentally, in recent years, there has been an increasing demand for higher image quality, and in order to realize particularly high-definition color image formation, the toner has been reduced in particle size and spheroidized. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner is being adopted.

  However, when a toner having a spherical shape or a small particle size is used, some problems may occur in cleaning the adhered matter such as residual toner attached to the outer peripheral surface of the photosensitive drum after transfer. One of them is that it is difficult to clean a toner having a spherical shape and a small particle size with a cleaning blade generally used as a cleaning member. The cleaning blade removes toner while rubbing the outer peripheral surface of the photosensitive drum, but the edge portion of the cleaning blade may be deformed due to frictional resistance with the outer peripheral surface of the photosensitive drum. When such deformation occurs, a minute space is generated between the outer peripheral surface of the photosensitive drum and the cleaning blade. The smaller the toner particle size, the easier it is to enter this space. The closer the toner that has entered the shape is, the easier it is to roll and the lower the frictional force. Such toner enters the space between the outer peripheral surface of the photosensitive drum and the cleaning blade and rolls, and eventually the toner may slip through the cleaning blade. For this reason, the toner having a spherical shape and a reduced particle size tends to easily cause a cleaning failure.

  As a countermeasure for preventing such a cleaning failure, a method of increasing the contact pressure of the cleaning blade to the outer peripheral surface of the photosensitive drum is taken. For example, a method has been proposed in which the surface pressure on the outer peripheral surface of the photosensitive drum of the cleaning blade is increased by making the ridge line portion of the tip edge portion in contact with the outer peripheral surface of the photosensitive drum in the cleaning blade an obtuse shape (for example, , See Patent Document 4). However, the frictional force between the outer peripheral surface of the photosensitive drum and the cleaning blade increases due to the increase in surface pressure. As a result, the wear of the photosensitive drum and the cleaning blade may easily progress. Further, when the above-described surface pressure is high, stick-slip in which the cleaning blade vibrates irregularly is likely to occur, and blade squeal due to stick-slip and blade turn-up are likely to occur. Also from the viewpoint of suppressing the occurrence of such stick-slip, it is important to apply an appropriate amount of a protective agent to the outer peripheral surface of the photosensitive drum.

  Here, even when an appropriate amount of protective agent is applied to the outer peripheral surface of the photosensitive drum, the following situation may occur when the layer is not uniformly thinned. That is, in such a case, the static friction coefficient μ is not uniform on the outer peripheral surface of the photosensitive drum. Therefore, the transfer of the toner image is not performed well, and various image abnormalities such as a void in the image portion called “worm bite” and a spot-like white dropout in the image portion called “Bosseki” occur. There is.

  The following two patterns are conceivable for the order of the two treatments of applying the protective agent and cleaning the deposits after the transfer. That is, there are two patterns: a post-application cleaning relationship where the protective agent is applied first and cleaning is later, and a post-cleaning application relationship where the cleaning is applied first and the protective agent is applied later. In these two patterns, the above-mentioned image abnormality occurrence mechanism is different as follows.

  In the post-application cleaning, a protective agent is applied to the outer peripheral surface of the photosensitive drum in which toner remains before being removed by the cleaning member. Here, on the outer peripheral surface of the photoconductive drum, a portion on which the toner forming the toner image is placed has a larger amount of deposits typified by residual toner after transfer to the transfer material than other portions. ing. When cleaning is performed after application of the protective agent, for such a portion where the amount of adhered matter is large, an application member such as an application brush for applying the protective agent applies the protective agent once applied to the toner. May be scraped off together. Furthermore, a cleaning member that performs cleaning after application may scrape the protective agent together with the toner. As a result, the applied amount of the protective agent on the outer peripheral surface of the photosensitive drum after cleaning becomes uneven. If a uniform protective agent layer cannot be formed on the outer peripheral surface of the photosensitive drum, the static friction coefficient μ of the outer peripheral surface is biased. In some cases, the static friction coefficient μ of the outer peripheral surface may not be low enough to transfer the toner image formed again after application of the protective agent. As a result, uneven transfer may occur, and various image abnormalities such as insect erosion and blurring may occur.

  In the post-cleaning application, the applied protective agent is not scraped off with the toner by the application member or the cleaning member, so that the situation that may occur in the post-application cleaning described above is avoided. However, if the protective agent is simply applied to the outer peripheral surface of the photosensitive drum and a uniform protective agent layer cannot be formed, the protective agent may be a granular lump on the outer peripheral surface of the photosensitive drum. is there. When such a lump of protective agent passes directly under the charging member as the photosensitive drum rotates, the protective agent may adhere to the charging member and contaminate the charging member. The contamination of the charging member causes non-uniform charging on the outer peripheral surface of the photosensitive drum, and as a result, various image abnormalities such as worm biting and vomit occur on the toner image itself formed on the outer peripheral surface of the photosensitive drum. Sometimes. In addition, if a uniform protective agent layer cannot be formed on the outer peripheral surface of the photosensitive drum, the static friction coefficient μ of the outer peripheral surface may not be uniform, or may not be low enough to transfer the toner image. There is. As a result, uneven transfer may occur, and various image abnormalities such as insect erosion and blurring may occur.

  Therefore, in order to form a uniform protective agent layer on the outer peripheral surface of the photoconductor drum, a protective agent leveling member that uniformly levels the protective agent after application is provided separately from the protective agent application member that applies the protective agent. Has been proposed (see Patent Documents 5 to 7).

  FIG. 6 is a view showing an example of a conventional protective agent leveling member. 6 shows a protective layer forming apparatus 500 having a conventional protective agent leveling member 520, together with a photosensitive drum 550 and a cleaning member 560 that rotate in the rotation direction indicated by an arrow AD1 in FIG. ing. The protective layer forming apparatus 500 includes a protective agent application member 510 and a protective agent leveling member 520.

  The cleaning member 560 includes a cleaning blade 561 and a blade holding member 562. The blade holding member 562 is fixed to the case 501 of the protective layer forming apparatus 500. The cleaning blade 561 is cantilevered by the blade holding member 562, and its free end abuts against the surface of the photosensitive drum 550 from the counter direction with respect to the movement direction of the outer peripheral surface 551 of the photosensitive drum 550 after transfer. Then, the cleaning blade 561 rubs the outer peripheral surface 551 of the photosensitive drum 550 after the transfer, and removes the deposits represented by the residual toner remaining on the outer peripheral surface 551.

  The protective agent application member 510 includes a brush roller 511, a solid protective agent 512, and a pressure member 513. The brush roller 511 is housed in the case 501 so that the hair tip is pressed against the photosensitive drum 550 at a position downstream of the cleaning member 560 in the rotation direction of the photosensitive drum 550. The brush roller 511 is rotationally driven in a rotational direction opposite to the rotational direction of the photosensitive drum 550, as indicated by an arrow AD2 in FIG. The solid protective agent 512 has a rectangular parallelepiped shape extending substantially parallel to the rotation axis of the brush roller 511, and is pressed against the brush roller 511 by a pressure member 513 from the side opposite to the photosensitive drum 550 side. . The pressure member 513 is a compression spring. The brush roller 511 rotates in the direction of the arrow AD2 to scrape off the protective agent from the solid protective agent 512 and apply the scraped protective agent to the outer peripheral surface 551 of the photosensitive drum 550 after cleaning by the cleaning member 560. .

The protective agent leveling member 520 includes a blade 521 and a holding member 522. The blade 521 is disposed at a position downstream of the protective agent applying member 510 in the rotation direction of the photosensitive drum 550. The blade 521 is provided on the outer peripheral surface 551 of the photosensitive drum 550.
In addition, it is fixed to the case 501 via the holding member 522 so that the leading edge portion 521a abuts from the trailing direction with respect to the rotational direction. When the photosensitive drum 550 after application of the protective agent rotates in the direction of the arrow AD1 and the outer peripheral surface 551 on which the protective agent is applied passes directly below the front edge portion 521a, the blade 521 has a front edge portion 521a. Evenly protect the agent. As a result, a uniform protective agent layer is formed on the outer peripheral surface 551 of the photosensitive drum 550.

  FIG. 7 is a view showing another example of a conventional protective agent leveling member. The protective layer forming apparatus 600 having this other example of the protective agent leveling member 610 is different from the protective layer forming apparatus 500 shown in FIG. 6 only in the protective agent leveling member 610. Therefore, in FIG. 7, the same components as those of the protective layer forming apparatus 500 shown in FIG. 6 are denoted by the same reference numerals as those in FIG. The duplicate description of is omitted.

  This other protective agent leveling member 610 also has a blade 611 and a holding member 612. In this alternative example, the blade 611 has a tip edge portion 611 a that is in contact with the outer peripheral surface 551 of the photosensitive drum 550 from the counter direction with respect to the rotation direction. Further, the leading edge portion 611 a of the blade 611 has an obtuse angled ridge portion, and the obtuse angled leading edge portion 611 a is in contact with the outer peripheral surface 551 of the photosensitive drum 550.

  Also in this other example, when the outer peripheral surface 511 of the photosensitive drum 550 to which the protective agent is applied passes immediately below the front edge portion 611a of the blade 611, the front edge portion 611a uniformly equalizes the protective agent. As a result, a uniform protective agent layer is formed on the outer peripheral surface 511 of the photosensitive drum 550.

  By the way, in the conventional protective layer forming apparatus as described with reference to FIGS. 6 and 7, the following phenomenon may occur depending on the environmental temperature. For example, in a low temperature environment such as less than 15 ° C., the brush roller becomes hard and the protective agent grinding force increases, and as a result, the amount of the protective agent applied may increase. In this case, the protective agent leveling members 520 and 610 shown in FIGS. 6 and 7 may not be able to level the supplied protective agent, and excess protective agent may slip through and fly to the charging roller for charging. There is a risk of contaminating the roller, leading to a reduction in image quality.

  Also, in a high temperature environment such as 27 ° C. or higher, the brush roller becomes soft and the protective agent grinding force decreases, and as a result, the amount of protective agent applied may decrease. In this case, the amount of the protective agent on the photosensitive drum 550 may become too small. Such a decrease in the protective agent reduces the cleaning property by the cleaning member 560, makes it easy for filming to occur, and may cause a reduction in image quality.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rubbing member for leveling a protective agent that can stably obtain a high-quality image over a long period of time in an image forming apparatus.

  In order to solve the above-described problem, the invention according to claim 1 is an image forming method in which a toner image is formed on an image forming surface having a predetermined width and circulated, and the toner image is transferred to a sheet and fixed on the sheet. Mounted on the apparatus, the image forming surface is protected, and the image forming surface coated with a protective agent that imparts lubricity to the image forming surface is rubbed to level the protective agent. The rubbing member for forming the protective agent layer has a strip shape extending substantially parallel to the width direction of the image forming surface, and a long edge of the rubbing member is formed on the image forming surface in the width direction. A friction plate comprising: a contact plate that makes contact over the entire width; and a support portion that supports the contact plate so that the contact state of the contact plate with the image forming surface can be changed. It is a member.

  According to the first aspect of the present invention, the contact state of the contact plate with the image forming surface can be changed. For this reason, for example, the protection after leveling by rubbing is changed by appropriately changing the contact state of the contact plate on the assumption that the coating amount of the protective agent is applied to the image forming surface due to the environmental temperature as described above. Since the coating amount of the agent can be made appropriate, it becomes possible to obtain a high-quality image stably over a long period of time.

1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. It is an enlarged block diagram which shows the structure of the process cartridge in 1st Embodiment. It is a figure which shows the protective layer forming apparatus in 1st Embodiment with a photoreceptor drum and a cleaning member. It is an enlarged block diagram which shows the structure of the process cartridge in 2nd Embodiment. It is a figure which shows the protective layer forming apparatus in 2nd Embodiment with the photoreceptor drum and the cleaning member. It is a figure which shows an example of the conventional protective agent leveling member. It is a figure which shows another example of the conventional protective agent leveling member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment will be described with reference to FIGS.

  The image forming apparatus according to the first embodiment of the present invention will be described below. First, a basic configuration of the image forming apparatus will be described. FIG. 1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus 100 includes a printer unit 1, a paper feed unit 10, and a document conveyance reading unit 20. The document conveying / reading unit 20 includes a scanner 21 serving as a document reading device fixed on the printer unit 1 and an ADF 22 serving as a document conveying device supported by the scanner 21.

  The printer unit 1 includes four process cartridges 2Y, 2M, 2C, and 2K for forming yellow (Y), magenta (M), cyan (C), and black (K) toner images. The process cartridges 2Y, 2M, 2C, and 2K for the respective colors are detachably attached to the casing 100a of the image forming apparatus 100.

  Further, the printer unit 1 includes a control unit 8 that controls the operation of each component of the image forming apparatus 100 including the process cartridges 2Y, 2M, 2C, and 2K. The printer unit 1 also includes a temperature sensor 9 that measures the environmental temperature inside the image forming apparatus 100.

  The process cartridges 2Y, 2M, 2C, and 2K for the respective colors have photosensitive drums 3Y, 3M, 3C, and 3K arranged at a predetermined pitch above the intermediate transfer belt 41 that is rotationally driven in the direction of the arrow in the drawing. ing. A toner image based on Y, M, C, and K image information is formed on the photosensitive drums 3Y, 3M, 3C, and 3K for each color as described later.

  Above the process cartridges 2Y, 2M, 2C, and 2K, an optical writing unit 30 serving as a latent image forming unit is provided. The optical writing unit 30 includes a laser diode, a polygon mirror, various lenses, and the like. The optical writing unit 30 drives the laser diode based on image information read by the scanner 21 or image information sent from an external personal computer. The optical writing unit 30 optically scans the photosensitive drums 3Y, 3M, 3C, and 3K of the process cartridges 2Y, 2M, 2C, and 2K. Specifically, the optical writing unit 30 deflects the laser light L in the direction of the rotation axis of the photosensitive member, respectively, with respect to the photosensitive drums 3Y, 3M, 3C, and 3K that are driven to rotate counterclockwise in the drawing. The light scanning process is performed by irradiating. Thereby, electrostatic latent images based on image information of each color of Y, M, C, and K are formed on the photosensitive drums 3Y, 3M, 3C, and 3K.

  Below the process cartridges 2Y, 2M, 2C, and 2K, an intermediate transfer unit 40 serving as a transfer unit is disposed. The intermediate transfer unit 40 includes an intermediate transfer belt 41 that is stretched and rotated by a plurality of rollers. The intermediate transfer belt 41 is an endless belt made of a heat-resistant material such as polyimide or polyamide and made of a base adjusted to a medium resistance. Then, the intermediate transfer unit 40 forms a primary transfer nip by sandwiching the intermediate transfer belt between the photosensitive drums 3Y, 3M, 3C, and 3K and primary transfer rollers 42Y, 42M, 42C, and 42K to which a predetermined voltage is applied. To do. Further, the intermediate transfer unit 40 forms a secondary transfer nip by sandwiching the intermediate transfer belt 41 between the secondary transfer backup roller 43 and the secondary transfer roller 44 to which a predetermined voltage is applied. Further, the intermediate transfer unit 40 includes a cleaning device 45 that removes transfer residual toner remaining on the intermediate transfer belt 41. The toner images on the photosensitive drums 3Y, 3M, 3C, and 3K formed by the process cartridges 2Y, 2M, 2C, and 2K are transferred to the intermediate transfer belt 41 at the primary transfer nip. The toner image transferred onto the intermediate transfer belt 41 is transferred to a sheet as a transfer medium at the secondary transfer nip. The residual transfer toner remaining on the intermediate transfer belt 41 after passing through the secondary transfer nip is removed by the cleaning device 45.

  Below the intermediate transfer unit 40, there are a first receiving branch path 52, a receiving and conveying roller pair 53, a second receiving and branching path 54, a manual separation roller pair 55, a pre-transfer conveying path 56, a registration roller pair 57, and a conveying belt unit 58. A switchback device 59 is arranged. These components form a conveyance path for paper fed from the paper feed unit 10 or the manual feed tray 51.

  A fixing device 60 is disposed below the intermediate transfer unit 40. In the fixing device 60, a fixing nip is formed between the fixing belt 61 and the pressure roller 62. The sheet on which the full-color toner image is transferred at the secondary transfer nip is conveyed into the fixing device 60 by the conveying belt unit 58, and the toner image is fixed by pressure and heat received at the fixing nip. The sheet on which the toner image is fixed is sent out toward the paper discharge roller pair 63.

  In the single-sided print mode in which an image is formed only on the first surface of the paper P, the paper P sandwiched between the paper discharge nips between the rollers of the paper discharge roller pair 63 is directly discharged out of the apparatus and discharged into the paper discharge tray 64. Stacked on top. In the double-sided print mode in which images are formed on both sides of the paper P, the paper P sandwiched in the paper discharge nip is returned in the reverse direction and enters the switchback device 59. Then, after being turned upside down in the switchback device 59, it is sent again to the secondary transfer nip, and the other side of the image is subjected to image secondary transfer processing and fixing processing.

  The paper feed unit 10 includes four paper feed cassettes 12, paper feed rollers 13, a separation roller pair 14, a paper feed path 15, and a transport roller pair 16 arranged in four stages in a paper bank 11. The paper feeding unit 10 rotates the paper feeding roller 13 based on a control signal from the printer unit 1 to separate the uppermost paper P in the paper bundle in the paper feeding cassette 12 into the separation roller pair 14. To send. The paper P that has been separated into one sheet by the separation roller pair 14 and then sent to the paper feed path 15 passes through the transport nips of the plurality of transport roller pairs 16 provided in the paper feed path 15, and the printer unit 1. To the first receiving branch 52.

  A pre-transfer conveyance path 56 for conveying the sheet P immediately before the secondary transfer nip branches into a first reception branch path 52 and a second reception branch path 54 on the upstream side in the sheet conveyance direction. The sheet P sent out from the sheet feeding path 15 of the sheet feeding unit 10 is received by the first receiving branch path 52 of the printer unit 1, and then the receiving transport roller pair 53 disposed in the first receiving branch path 52. Is sent to the pre-transfer conveyance path 56 via the conveyance nip. The paper P manually fed from the manual feed tray 51 is separated into one sheet by the manual separation roller pair 55, then sent out toward the second receiving branch path 54, and sent to the pre-transfer conveyance path 56.

  The scanner 21 fixed on the printer unit 1 has a fixed reading unit and a moving reading unit as reading means for reading an image of a document (not shown). A fixed reading unit having a light source, a reflection mirror, an image reading sensor such as a CCD, and the like is disposed immediately below a first contact glass (not shown) fixed to the upper wall of the casing of the scanner 21 so as to contact the document. Then, when the document conveyed by the ADF 22 passes over the first contact glass, the light emitted from the light source is sequentially reflected by the document surface, and is received by the image reading sensor via a plurality of reflection mirrors. Thus, the original is scanned without moving the optical system including the light source and the reflecting mirror.

  The moving reading unit of the scanner 21 is disposed immediately below a second contact glass (not shown) fixed to the upper wall of the casing of the scanner 21 so as to come into contact with the document, and an optical system including a light source, a reflection mirror, and the like. It can be moved in the left-right direction in the figure. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected by a document (not shown) placed on the second contact glass and then passed through a plurality of reflecting mirrors. The image is received by an image reading sensor fixed to the scanner body. Accordingly, the original is scanned while moving the optical system.

  Next, the configuration of the process cartridges 2Y, 2M, 2C, and 2K will be described in detail. FIG. 2 is an enlarged configuration diagram showing the configuration of the process cartridge in the first embodiment. The process cartridges 2Y, 2M, 2C, and 2K have the same configuration except that the colors of the toners used are different from each other. Therefore, the following description omits the reference numerals indicating the distinction of colors.

  The process cartridge 2 includes a charging device 4 and a developing device 5 around the photosensitive drum 3. The charging device 4 uniformly charges the outer peripheral surface 3 a of the photosensitive drum 3. The developing device 5 develops the electrostatic latent image formed on the outer peripheral surface 3 a of the photosensitive drum 3 with toner by scanning exposure of the laser light L from the optical writing unit 30.

  In the present embodiment, the outer peripheral surface 3a of the rotating photosensitive drum 3 corresponds to an example of “an image forming surface having a predetermined width and circulatingly moving” according to the present invention. The photosensitive drum 3 corresponds to an example of the image carrier referred to in the present invention. A combination of the charging device 4, the optical writing unit 30, and the developing device 5 corresponds to an example of the image forming unit referred to in the present invention. Further, the intermediate transfer unit 40 shown in FIG. 1 corresponds to an example of a transfer unit according to the present invention, and the fixing device 60 corresponds to an example of a fixing unit according to the present invention.

  Further, the process cartridge 2 has a cleaning member 6 for removing transfer residual toner attached to the outer peripheral surface 3 a of the photosensitive drum 3 around the photosensitive drum 3, and a protective agent on the outer peripheral surface 3 a of the photosensitive drum 3. And a protective layer forming apparatus 7 for forming the above layer.

  The cleaning member 6 is fixed to the protective layer forming apparatus 7 as described later. The protective layer forming apparatus 7 includes a protective agent application member 71 that applies a protective agent to the outer peripheral surface 3 a of the photosensitive drum 3, and a protective agent leveling member that equalizes the protective agent applied to the outer peripheral surface 3 a of the photosensitive drum 3. 72. The protective agent application member 71 corresponds to an example of the protective agent application member according to the present invention.

  The photosensitive drum 3 rotates in the rotation direction indicated by the arrow D1 in FIG. By this rotation, the outer peripheral surface 3a sequentially passes through the charging device 4, the developing device 5, the primary transfer roller 42, the cleaning member 6, and the protective layer forming device 7 in this order.

  The photoconductor drum 3 is an organic photoconductor that has a cylindrical shape and rotates in a rotation direction indicated by an arrow D1 with the central axis of the cylindrical shape as a rotation axis, and a surface protective layer is formed on the outer peripheral surface 3a with a polycarbonate-based resin. Is formed. The charging device 4 includes a charging roller 4 a configured by covering a conductive metal core with an intermediate resistance elastic layer. The charging roller 4a is connected to a power source (not shown) and is applied with a predetermined voltage. The charging roller 4 a is disposed with a small gap with respect to the photosensitive drum 3. This minute gap is caused by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 4 a to bring the surface of the spacer member into contact with the outer peripheral surface 3 a of the photosensitive drum 3. Can be set. Further, the charging device 4 is provided with a charging cleaning member 4b that cleans by contacting the surface of the charging roller 4a.

  In the developing device 5, a developing sleeve 5 a including a magnetic field generating unit is disposed at a position facing the outer peripheral surface 3 a of the photosensitive drum 3. The developing sleeve 5a rotates in the rotation direction indicated by the arrow D2. Below the developing sleeve 5a, there are provided two screws 5b for mixing toner introduced from a toner bottle (not shown) with a magnetic carrier and pumping it up to the developing sleeve 5a while stirring. The developer composed of toner and magnetic carrier pumped up by the developing sleeve 5a is regulated to a predetermined developer layer thickness by the doctor blade 5c, and is carried on the developing sleeve 5a. The surface of the developing sleeve 5a moves in the same direction at the position facing the photosensitive drum 3, while carrying and carrying the developer, and supplies toner to the latent image surface of the photosensitive drum 3 to form a toner image. In the present embodiment, the configuration of the two-component developing type developing device 5 is shown in FIG. 2, but the present invention is not limited to this, and a one-component developing type developing device can also be applied.

  The cleaning member 6 has a cleaning blade 6a and a blade holding member 6b. The blade holding member 6 b is fixed to the case 7 a of the protective layer forming device 7. The cleaning blade 6a is cantilevered by a blade holding member 6b, and the free end of the cleaning blade 6a from the counter direction with respect to the moving direction of the outer peripheral surface 3a of the photosensitive drum 3 from the outer peripheral surface 3a of the photosensitive drum 3 after transfer. Abut. Then, the cleaning blade 6a rubs the outer peripheral surface 3a of the photosensitive drum 3 after the transfer, and removes deposits represented by residual toner remaining on the outer peripheral surface 3a. The material used for the cleaning blade 6a is not particularly limited, and elastic bodies such as urethane rubber, hydrin rubber, silicone rubber, and fluorine rubber can be used singly or in a blend. Further, the contact portion of the rubber blade with the photosensitive drum 3 may be coated with a low friction material or impregnated. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fine particles and inorganic fine particles may be dispersed therein. The cleaning blade 6a is fixed to a blade holding member 6b made of metal, plastic, ceramic or the like by any method such as adhesion and fusion. In this embodiment, the cleaning blade 6a is made of an insulating rubber, but the cleaning blade 6a may be conductive. Further, instead of the cleaning blade 6a, a cleaning brush in which a bias is applied to a conductive brush having a medium resistance to a low resistance may be used.

  Next, the protective layer forming apparatus 7 will be described. FIG. 3 is a view showing the protective layer forming apparatus according to the first embodiment together with the photosensitive drum and the cleaning member. In FIG. 3, the rotation direction of the photosensitive drum 3 and the relative position of the protective layer forming apparatus 7 with respect to the cleaning member 6 are easily compared with the conventional protective layer forming apparatus shown in FIGS. 6 and 7. The position is matched with FIG. 6 and FIG. As a result, in FIG. 3 and FIG. 2, the rotation direction of the photosensitive drum 3 and the relative position with respect to the cleaning member 6 are different from each other, but these two views of the protective layer forming device 7 are substantially the same. Show. Therefore, the same reference numerals as those in FIG. 2 are given to the components in FIG. 3, and the following description will be given with reference to FIGS. 2 and 3 without particularly distinguishing them.

  As described above, the protective layer forming apparatus 7 rubs the protective agent application member 71 that applies a protective agent to the outer peripheral surface 3 a of the photosensitive drum 3 and the outer peripheral surface 3 a of the photosensitive drum 3 to which the protective agent is applied. And a protective agent leveling member 72 for leveling the protective agent. The protective agent application member 71 corresponds to an example of the protective agent application member according to the present invention. First, the protective agent application member 71 will be described.

  The protective agent application member 71 includes a brush roller 71a, a solid protective agent 71b, and a pressure member 71c. The brush roller 71 a is accommodated in the case 7 a of the protective layer forming apparatus 7 so as to be rotatable about a rotation axis substantially parallel to the rotation axis of the photosensitive drum 3. The brush roller 71a is disposed on the downstream side of the cleaning member 6 with respect to the rotation direction of the photosensitive drum 3 (the direction of the arrow D1). The brush roller 71a is rotationally driven in a rotation direction indicated by an arrow D3 by a driving source (not shown), and rubs the outer peripheral surface 3a of the photosensitive drum 3 after the deposits are removed by the cleaning member 6. The solid protective agent 71b has a rectangular parallelepiped shape extending substantially parallel to the rotation axis of the brush roller 71a, and is pressed against the brush roller 71a from the side opposite to the photosensitive drum 3 side by a pressure member 71c. . The pressurizing member 71c is preferably a member that presses the solid protective agent 71b with a spring such as a plate spring or a compression spring, and a member using a compression spring as shown in FIGS. 2 and 3 is particularly suitable. The solid protective agent 71b is scraped off and consumed by the rotating brush roller 71a, and the thickness of the solid protective agent 71b decreases with time. However, the solid protective agent 71b is always in contact with the brush roller 71a because it is pressurized by the pressure member 71c. The brush roller 71 a applies the protective agent scraped off while rotating to the outer peripheral surface 3 a of the photosensitive drum 3. The protective agent scraped off from the solid protective agent 71b corresponds to an example of the protective agent referred to in the present invention. Further, the protective agent application member 71 may have a driving means (not shown) that swings the brush roller 71a or the solid protective agent 71b in a longitudinal direction substantially parallel to the rotation axis of the brush roller 71a. By swinging the brush roller 71a or the solid protective agent 71b, the coating unevenness is reduced and the protective agent can be applied more uniformly. The rotation direction of the brush roller 71a is preferably forward with respect to the rotation direction of the photosensitive drum 3, as indicated by an arrow D3 in FIGS. 2 and 3, but may be rotated in the reverse direction.

  The protective agent constituting the solid protective agent 71b protects the outer peripheral surface 3a of the photosensitive drum 3 and imparts lubricity to the outer peripheral surface 3a. As this protective agent, it is possible to use a dry solid hydrophobic protective agent, for example, zinc stearate. In addition to zinc stearate, those having the following stearic acid groups can be used as the protective agent forming the solid protective agent 71b. That is, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate and the like can be mentioned. Further, zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, and copper oleate having the same fatty acid group may be used as the protective agent forming the solid protective agent 71b. Examples of those having a fatty acid group also include zinc palmitate, cobalt palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, and calcium palmitate. In addition to these, as a protective agent forming the solid protective agent 71b, a metal salt of a fatty acid such as lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate, and cadmium ricolinolenate can be used. . Furthermore, waxes such as candelilla wax, carnauba wax, rice wax, wax, ooba oil, beeswax and lanolin can be used as the protective agent forming the solid protective agent 71b. More preferably, the protective agent contains inorganic fine particles. Examples of the fine particles include, but are not limited to, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, and graphite. For example, boron nitride has a crystal structure in which hexagonal mesh planes in which atoms are tightly combined are stacked at wide intervals, and the layers are bonded only by weak van der Waals forces, so the layers spread easily and the direction of the hexagonal mesh planes Slippery and exhibits excellent lubricity. By mixing such fine particles with a fatty acid metal salt, it becomes easy to extend the protective agent into a thin layer. Here, the protective agent exemplified above may be cooled after melting and used as a bar-shaped solid protective agent, but in addition to that, a powdered fatty acid metal salt and inorganic fine particles are mixed and compressed into a bar shape. And may be used as a solid protective agent. Alternatively, the protective agent in powder form may be accommodated in a mesh bag, the bag may be pressed against the brush roller 71a, and the protective agent in the bag may be scraped off by the brush roller 71a.

  Next, the protective agent leveling member 72 included in the protective layer forming apparatus 7 will be described. The protective agent leveling member 72 has a contact plate 72a and a support portion 72b. As shown in FIGS. 2 and 3, the abutting plate 72 a is formed by the support portion 72 b fixed to the case 7 a of the protective layer forming device 7 with respect to the rotation direction of the photosensitive drum 3 (arrow D 1). It is supported at a downstream position. The contact plate 72a is made of an elastic material and has a strip shape extending substantially parallel to the width direction of the outer peripheral surface 3a (image forming surface) of the photosensitive drum 3, and its long edge is in the width direction described above. Is in contact with the outer peripheral surface 3a of the photosensitive drum 3 over the entire width. The protective agent applied by the protective agent applying member 71 is rubbed and smoothed by the contact plate 72a that is in contact with the outer peripheral surface 3a of the photosensitive drum, and a protective agent layer is formed on the outer peripheral surface 3a of the photosensitive drum. Is done.

  The support portion 72b supports the contact plate 72a so as to be rotatable about a rotation shaft 72c extending substantially parallel to the width direction of the outer peripheral surface 3a of the photosensitive drum 3. Thereby, the support part 72b supports the contact plate 72a so that the contact posture with respect to the outer peripheral surface 3a of the photosensitive drum 3 can be changed. Specifically, the support portion 72b supports the contact plate 72a so as to be changeable between a trailing posture and a counter posture. The trailing posture is a posture in which the long end edge of the contact plate 72a is in contact with the outer peripheral surface 3a of the photosensitive drum 3 from the trailing direction. The counter posture is a posture in which the long end edge of the contact plate 72a contacts the outer peripheral surface 3a of the photosensitive drum 3 from the counter direction. In FIG. 3, the contact plate 72a in the counter posture is shown by a solid line, and the contact plate 72a in the trailing posture is shown by a dotted line.

  Such a change in the contact posture of the contact plate 72a is achieved by rotating the support portion 72a supporting the contact plate 72a around the rotation shaft 72c in a rotation direction indicated by an arrow D4 by a motor (not shown). Is done. In this embodiment, the rotation of the support portion 72 a is performed by the following control by the control unit 8 according to the environmental temperature measured by the temperature sensor 9.

  The environmental temperature measured by the temperature sensor 9 is sequentially stored in a memory (not shown). Then, when a predetermined timing comes in a period in which the sheet passing operation is not performed in the image forming apparatus 100 and the photosensitive drum 3 is stopped, the control unit 8 first determines the average temperature for the latest 30 minutes. Is calculated. And the control part 8 determines whether the average temperature is 15 degreeC or more.

  When the high temperature condition that the average temperature is 15 ° C. or higher is satisfied and the contact posture is the trailing posture, the control unit 8 does not perform anything and the trailing posture is maintained. On the other hand, when the high temperature condition is satisfied and the contact posture is the counter posture, the control unit 8 rotates the support portion 72a to change the contact posture to the trailing posture.

  When the low temperature condition that the average temperature is less than 15 ° C. is satisfied and the contact posture is the trailing posture, the control unit 8 rotates the support portion 72a to change the contact posture to the counter posture. On the other hand, when the low temperature condition is satisfied and the contact posture is the counter posture, the control unit 8 does not perform anything and the counter posture is maintained.

  A combination of the protective agent leveling member 72, the control unit 8, and the temperature sensor 9 corresponds to an example of a rubbing member according to the present invention, and an example of the protective agent leveling member according to the present invention. Is also equivalent. A combination of the protective layer forming apparatus 7, the control unit 8, and the temperature sensor 9 corresponds to an example of the protective layer forming apparatus according to the present invention. The contact plate 72a corresponds to an example of the contact plate according to the present invention, the support portion 72b corresponds to an example of the support portion according to the present invention, and the rotation shaft 72c rotates according to the present invention. It corresponds to an example of an axis. The control unit 8 corresponds to an example of the control unit according to the present invention, and the temperature sensor 9 corresponds to an example of the temperature sensor according to the present invention.

  In this embodiment, the timing for changing the contact posture is exemplified by a predetermined timing in the period during which the photosensitive drum 3 is stopped. However, the timing for changing the contact posture is not limited thereto. is not. The contact posture may be changed during a period in which the photosensitive drum 3 is rotating. In this case, the abutting plate 72a is separated from the outer peripheral surface 3a of the photosensitive drum 3 together with the supporting portion 72b so that the changing operation of the abutting posture does not hinder the rotation of the photosensitive drum 3. The plate 72a is rotated. Further, the rotation at this time is not limited to the operation of rotating the contact plate 72a via the space on the side opposite to the photosensitive drum 3, and the rotation on the side of the photosensitive drum 3 opened by the above-described separation. It may be an operation of rotating via a space.

  Further, in the present embodiment, as an example of the high temperature condition, the condition that the average temperature for the latest 30 minutes is 15 ° C. or more is illustrated, but the high temperature condition is not limited to such a condition. The high temperature condition may be, for example, a condition for the average temperature over a period other than the latest 30 minutes, or may be a condition for the measured temperature itself instead of the average temperature. The threshold temperature may also be a temperature other than 15 ° C.

  Further, in the present embodiment, the condition that the average temperature for the last 30 minutes is less than 15 ° C. is exemplified as an example of the low temperature condition, but the low temperature condition is not limited to such a condition. The low temperature condition may be, for example, a condition for the average temperature over a period other than the latest 30 minutes, or may be a condition for the measured temperature itself instead of the average temperature. The threshold temperature may also be a temperature other than 15 ° C.

  In the present embodiment, as an example of the temperature sensor according to the present invention, a temperature sensor 9 that measures the environmental temperature inside the image forming apparatus 100 is illustrated. However, the temperature sensor referred to in the present invention is not limited to this, and may be, for example, a sensor that is attached to the outer surface of the image forming apparatus 100 and measures the environmental temperature at the place where the image forming apparatus 100 is installed. .

  In the present embodiment, the contact linear pressure of the long end edge of the contact plate 72a with respect to the outer peripheral surface 3a of the photosensitive drum 3 is 0.008 N / cm or more and 72 N / cm or less. The material used for the abutting plate 72a is not particularly limited, and an elastic body such as urethane rubber, hydrin rubber, silicone rubber, or fluoro rubber may be used alone or blended in the same manner as the cleaning blade 6a. it can. In addition, these rubber blades may be those in which a contact portion with the photosensitive drum 3 is coated with a low friction material or impregnated. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fine particles and inorganic fine particles may be dispersed therein. The contact plate 72a is fixed to a support portion 72b made of metal, plastic, ceramic, or the like by any method such as adhesion or fusion.

  Here, in the present embodiment, the amount of the protective agent applied to the outer peripheral surface 3a of the photosensitive drum 3 may fluctuate due to a change in hardness of the brush roller 71a according to a change in the environmental temperature. Specifically, the brush roller 71a softens in a high temperature environment and the amount of the protective agent applied decreases, and in a low temperature environment, the brush roller 71a hardens and the amount of the protective agent applied increases. According to the present embodiment, the contact posture of the contact plate 72a with respect to the outer peripheral surface 3a of the photosensitive drum 3 can be changed. For this reason, it is assumed that the contact posture of the contact plate 72a is appropriately changed on the assumption that the amount of application of the protective agent to the outer peripheral surface 3a of the photosensitive drum 3 is changed, so that Since the coating amount of the protective agent can be made appropriate, it becomes possible to obtain a high-quality image stably over a long period of time.

  Further, according to the present embodiment, the support portion 72b supports the contact plate 72a so as to be rotatable about the rotation shaft 72c extending substantially parallel to the width direction of the outer peripheral surface 3a of the photosensitive drum 3. Thereby, the contact posture can be changed by a simple operation of rotating the contact plate 72a around the rotation shaft 72c.

  In the present embodiment, as an example of the rotation of the contact plate according to the present invention, the rotation about the rotation shaft 72c provided in the support portion 72b is illustrated. However, the rotation of the contact plate referred to in the present invention is not limited to this, for example, an operation in which a rotation shaft is provided on the contact plate and the contact plate is rotated around the rotation shaft. Etc.

  Further, according to the present embodiment, the change in the contact posture is between a trailing posture suitable for a case where the amount of the protective agent applied is small and a counter posture suitable for a case where the amount of the protective agent applied is large. Done. Thereby, the coating amount of the protective agent after leveling by rubbing can be made more appropriate.

  Further, according to the present embodiment, as described above, the contact posture is changed according to the environmental temperature that causes the increase or decrease in the coating amount of the protective agent. Thereby, the coating amount of the protective agent after leveling by rubbing can be made more appropriate.

  Further, according to the present embodiment, the contact plate 72a is supported in a trailing posture when a high temperature condition that tends to reduce the amount of the protective agent applied is satisfied. When the low temperature condition that tends to increase the amount of the protective agent is satisfied, the contact plate 72a is supported in a counter posture. Thereby, the coating amount of the protective agent after leveling by rubbing can be made more appropriate.

  In the present embodiment, the contact linear pressure of the long end edge of the contact plate 72a with respect to the outer peripheral surface 3a of the photosensitive drum 3 is 0.008 N / cm or more and 72 N / cm or less. As a result, the amount of the protective agent passing between the outer peripheral surface 3a of the photosensitive drum 3 and the contact plate 72a makes the protective layer of an appropriate thickness uniform while suppressing the adhesion of the protective agent to the charging roller 4a. The amount is suitable for being formed. The contact linear pressure is preferably 0.008 N / cm or more and 72 N / cm or less, and more preferably 0.01 N / cm or more and 70 N / cm or less, as in the present embodiment. The contact linear pressure is more preferably 1 N / cm or more and 50 N / cm or less.

  In the present embodiment, the protective agent is mainly composed of zinc stearate, which is a fatty acid metal salt, and contains inorganic fine particles. By using a fatty acid metal salt as a main component, particularly zinc stearate, a good hydrophobic protective agent can be obtained. Furthermore, it becomes easy to extend the protective agent into a thin layer by containing inorganic fine particles.

  Next, a second embodiment will be described. The second embodiment is different from the first embodiment in the protective agent leveling member. On the other hand, the basic configuration of the image forming apparatus is the same as that of the first embodiment. Hereinafter, the second embodiment will be described by paying attention to differences from the first embodiment, and description of common points will be omitted.

  FIG. 4 is an enlarged configuration diagram showing the configuration of the process cartridge in the second embodiment, and FIG. 5 is a diagram showing the protective layer forming apparatus in the second embodiment together with the photosensitive drum and the cleaning member. 4 and 5, the same components as those of the first embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals as those in FIGS. 2 and 3. I will omit duplicate explanations for these equivalent components.

  In the process cartridge 200 of this embodiment, the protective agent leveling member 211 of the protective layer forming apparatus 210 includes a contact plate 211a, a support portion 211b, and a contact pressure adjusting portion 211c. The protective agent leveling member 211 is supported by the case 7a of the protective layer forming apparatus 210 via the contact pressure adjusting portion 211c. In this embodiment, the contact posture of the contact plate 211a with respect to the outer peripheral surface 3a of the photosensitive drum 3 is fixed to the counter posture.

  The contact pressure adjusting unit 211c, under the control of the control unit 8, displaces the position of the contact plate 211a in the adjustment direction DP1 along the width direction of the contact plate 211a, so that the outer peripheral surface 3a of the photosensitive drum 3 is displaced. The contact pressure of the contact plate 211a with respect to is adjusted. That is, the contact pressure adjusting unit 211c increases the contact pressure by displacing the contact plate 211a toward the outer peripheral surface 3a of the photosensitive drum 3 in the adjustment direction DP1. Further, the contact pressure adjusting unit 211c lowers the contact pressure by displacing the contact plate 211a in the adjustment direction DP1 on the side opposite to the outer peripheral surface 3a side of the photosensitive drum 3. The contact pressure adjusting portion 211c performs such displacement of the contact plate 211a by displacing the support portion 211b in the adjustment direction DP1 using an actuator such as a linear motion motor.

  In the present embodiment, the operation of the contact pressure adjusting unit 211 c is performed by the following control by the control unit 8 according to the environmental temperature measured by the temperature sensor 9.

  The environmental temperature measured by the temperature sensor 9 is sequentially stored in a memory (not shown). Then, when a predetermined timing comes in a period in which the sheet passing operation is not performed in the image forming apparatus 100 and the photosensitive drum 3 is stopped, the control unit 8 first determines the average temperature for the latest 30 minutes. Is calculated. And the control part 8 determines whether the average temperature is 15 degreeC or more.

  When the high temperature condition that the average temperature is 15 ° C. or higher is satisfied, the control unit 8 adjusts the contact pressure so that the contact plate 211a is displaced by a predetermined distance in the adjustment direction DP1 toward the outer peripheral surface 3a of the photosensitive drum 3. The unit 73 is operated. The displacement amount at this time is set to such a displacement amount that the contact pressure of the contact plate 211a is 0.01 N / cm or more and 9 N / cm or less.

  On the other hand, when the low temperature condition that the average temperature is less than 15 ° C. is satisfied, the controller 8 causes the contact plate 211a to be displaced by a predetermined distance in the adjustment direction DP1 on the side opposite to the outer peripheral surface 3a side of the photosensitive drum 3. The contact pressure adjusting unit 73 is operated. The displacement amount at this time is set to a displacement amount at which the contact pressure of the contact plate 211a is 10 N / cm or more and 80 N / cm or less.

  In the present embodiment, a combination of the protective agent leveling member 211, the control unit 8, and the temperature sensor 9 corresponds to an example of a rubbing member according to the present invention. A combination of the protective layer forming apparatus 210, the control unit 8, and the temperature sensor 9 corresponds to an example of the protective layer forming apparatus according to the present invention. The contact plate 211a corresponds to an example of the contact plate according to the present invention, and the combination of the support portion 211b and the contact pressure adjusting portion 211c corresponds to an example of the support portion according to the present invention.

  In the present embodiment, the timing for changing the contact pressure is a predetermined timing in the period during which the photosensitive drum 3 is stopped, similarly to the timing for changing the contact posture in the first embodiment. Yes. However, the change timing of the contact pressure is not limited to this, and the change of the contact pressure may be performed, for example, during a period in which the photosensitive drum 3 is rotating.

  In this embodiment, the contact pressure (linear pressure) of the long end edge of the contact plate 211a with respect to the outer peripheral surface 3a of the photosensitive drum 3 is 0.01 N / cm or more and 80 N / cm or less. The material used for the contact plate 211a is the same as that of the contact plate 72a in the first embodiment.

  According to the second embodiment described above, the contact pressure of the contact plate 211a against the outer peripheral surface 3a of the photosensitive drum 3 can be changed. For this reason, it is assumed that the contact pressure of the contact plate 211a is appropriately changed on the assumption that the amount of the protective agent applied to the outer peripheral surface 3a of the photosensitive drum 3 is changed, so that Since the coating amount of the protective agent can be made appropriate, it becomes possible to obtain a high-quality image stably over a long period of time.

  That is, in a low temperature environment such as less than 15 ° C., the contact pressure of the contact plate 211a is increased to suppress slipping of excess protective agent against the increase in the supply amount of the protective agent due to the hardening of the brush roller 71a. Therefore, it is possible to prevent the image quality from being deteriorated due to contamination of the charging roller 4a. Further, in a high temperature environment of 15 ° C. or higher, for example, 27 ° C., etc., the contact pressure of the contact plate 211a is lowered to reduce the protective agent against the decrease in the supply amount of the protective agent due to the softening of the brush roller 71a. By reducing the force, it is possible to secure the necessary supply of protective agent. As a result, by improving the protection of the outer peripheral surface 3a of the photosensitive drum 3, it is possible to prevent image quality deterioration due to filming. Thus, according to the present embodiment, it is possible to stably obtain a high-quality image over a long period of time.

  Further, according to the present embodiment, the contact pressure of the contact plate 211 a is changed according to the environmental temperature measured by the temperature sensor 9 under the control of the control unit 8. By applying the contact pressure change as described above using the environmental temperature that directly affects the amount of the protective agent applied after leveling by rubbing as a trigger, the amount of the protective agent applied can be made more appropriate. it can.

  Further, according to the present embodiment, the contact pressure is lowered when the environmental temperature measured by the temperature sensor 9 satisfies the above high temperature condition and the amount of the protective agent applied tends to decrease. Thereby, since the required supply amount of a protective agent can be ensured, the coating amount of the protective agent can be made more appropriate.

  Further, according to the present embodiment, the contact pressure is increased when the environmental temperature measured by the temperature sensor 9 satisfies the low temperature condition and the amount of the protective agent applied tends to increase. Thereby, since the removal amount of a protective agent can be increased, the application amount of a protective agent can be made more appropriate.

  In the present embodiment, the contact pressure (linear pressure) of the contact plate 211a with respect to the outer peripheral surface 3a of the photosensitive drum 3 is preferably 0.008 N / cm or more and 82 N / cm or less. As a result, the amount of the protective agent passing between the outer peripheral surface 3a of the photosensitive drum 3 and the contact plate 211a makes the protective layer of an appropriate thickness uniform while suppressing adhesion of the protective agent to the charging roller 4a. The amount is suitable for being formed. The contact linear pressure is more preferably 0.01 N / cm or more and 80 N / cm or less as in the present embodiment.

  Furthermore, the contact pressure of the contact plate 211a is preferably 0.01 N / cm or more and 9 N / cm or less when the high temperature condition is satisfied as in this embodiment, and when the low temperature condition is satisfied. Is preferably 10 N / cm or more and 80 N / cm or less.

  In the present embodiment, as a configuration for changing the contact pressure of the contact plate 211a, the contact pressure that displaces the support portion 211b of the contact plate 211a in the adjustment direction DP1 using an actuator such as a linear motion motor. The adjustment part 211c is illustrated. However, the configuration for changing the contact pressure is not limited to this. For example, a spring may be provided in the support portion 211b and the contact pressure may be changed by expanding and contracting the spring. Good.

  In the present embodiment, the counter posture is exemplified as the contact posture of the contact plate 211a. However, the contact posture of the contact plate 211a whose contact pressure is changed is not limited to this, and may be a trailing posture.

  The first embodiment and the second embodiment described above are merely representative examples of the present invention, and the present invention is not limited to these embodiments. That is, those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are also included in the scope of the present invention as long as they include the structures of the rubbing member, protective layer forming apparatus, and image forming apparatus of the present invention.

  For example, in both the first embodiment and the second embodiment described above, as an example of the protective layer forming apparatus according to the present invention, a protective layer forming apparatus that forms a protective agent layer on the outer peripheral surface 3a of the photosensitive drum 3 is used. 7 is illustrated, but the protective layer forming apparatus referred to in the present invention is not limited to this. The protective layer forming apparatus according to the present invention may form a protective agent layer on the outer peripheral surface of the intermediate transfer belt 41, for example. In this case, the protective layer forming device may be provided adjacent to the cleaning device 45 of the intermediate transfer belt 41 or may be provided by being incorporated in the cleaning device 45. In this case, the outer peripheral surface of the intermediate transfer belt 41 that circulates corresponds to an example of “an image forming surface that circulates with a predetermined width” according to the present invention. The intermediate transfer belt 41 corresponds to an example of an image carrier according to the present invention. The protective layer leveling member included in the protective layer forming apparatus for the intermediate transfer belt 41 corresponds to an example of the rubbing member according to the present invention. Furthermore, the protective layer forming apparatus referred to in the present invention is not limited to being provided only on either the photosensitive drum or the intermediate transfer belt, but may be provided on both the photosensitive drum and the intermediate transfer belt.

  Further, in both the first embodiment and the second embodiment described above, the contact plates 72a and 211a are applied as an example of the rubbing member according to the present invention in accordance with the environmental temperature measured by the temperature sensor 9. The form in which the contact state such as the contact posture and the contact pressure is changed is illustrated. However, the rubbing member according to the present invention is not limited to this, and may be, for example, a member whose contact state is changed according to a changing operation by the user. That is, a user who recognizes the temperature by looking at a thermometer provided independently of the image forming apparatus or based on his / her own experience changes the contact state by performing a change operation. Also good.

  Next, an example in which image formation is actually performed using the image forming apparatus corresponding to the above-described embodiment will be described. In the following embodiments, the contact line pressure of the contact plate 72a of the protective agent leveling member 72 to the outer peripheral surface 3a of the photosensitive drum and the material of the protective agent will be specifically described, but these are only examples. Thus, the present invention is not limited to these.

  First, an example corresponding to the above-described first embodiment will be described together with a comparative example to be compared with the example.

(First embodiment)
In the first example, the image forming apparatus “image MP MP4500” manufactured by Ricoh Co., Ltd. was modified like the image forming apparatus 100 of the first embodiment described with reference to FIGS. First, the protective agent leveling member in the protective layer forming device mounted on the image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. was replaced with the protective agent leveling member 72 shown in FIGS. Moreover, the control part 8 and the temperature sensor 9 shown in FIG.2 and FIG.3 were mounted. The contact linear pressure in the longitudinal direction of the contact plate 72a was set to “10 N / cm”.

  Furthermore, in the first example, a protective agent in which zinc stearate was incorporated with boron nitride as inorganic fine particles was used. The compounding ratio (mass ratio) of zinc stearate and boron nitride is “9” for zinc stearate and “1” for boron nitride.

  Except for the protective agent leveling member 72 and the protective agent, the image forming apparatus of the first example was obtained using the components of the image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. as they were.

(Second to ninth embodiments)
As described in Table 1 to be described later, the second to ninth embodiments are performed under the same conditions as the first embodiment except that the contact linear pressure is changed in the range of 0.005 N / cm to 80 N / cm. An image forming apparatus was obtained.

(First comparative example)
In the first comparative example, an image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. was used as it was. In this image forming apparatus imagio MP C4500, the protective agent leveling member in the protective layer forming apparatus uses a blade like the protective agent leveling member 520 in the conventional protective layer forming apparatus 500 described with reference to FIG. It has become a thing. The leading edge portion is in contact with the outer peripheral surface of the photosensitive drum. That is, in the first comparative example, like the protective agent leveling member 520 in the conventional protective layer forming apparatus 500 described with reference to FIG. 6, the leading edge portion is in the trailing direction on the outer peripheral surface of the photosensitive drum. Abut. However, in the first comparative example, the contact line pressure is adjusted to “10 N / cm”.

(Second comparative example)
In the second comparative example, an image forming apparatus imagio MP C5002 manufactured by Ricoh Co., Ltd. was used as it was. In this image forming apparatus imgio MP C5002, the protective agent leveling member in the protective layer forming device uses a blade like the protective agent leveling member 610 in the conventional protective layer forming device 600 described with reference to FIG. It has become a thing. That is, the blade has an obtuse angle at the ridgeline at the tip edge. Further, the leading edge portion is in contact with the outer peripheral surface of the photosensitive drum from the counter direction like a protective agent leveling member 610 shown in FIG. Also in this second comparative example, the contact linear pressure is adjusted to “10 N / cm”.

(Evaluation)
In each of the image forming apparatuses of the first to ninth embodiments and the first and second comparative examples obtained in this way, the image area ratio is 5% and the A4 size test chart covers 100,000 sheets. The images were continuously formed. The 100,000 sheets of images were formed in two environments: a normal temperature environment where the temperature was 23 ° C. and a relative humidity of 50% RH, and a low temperature environment where the temperature was 10 ° C. and the relative humidity was 15% RH. . However, after image formation under one environment, the photosensitive drum, the charging roller, and the protective agent coating device of each example and each comparative example are replaced with new ones, and the same conditions except for the environment are used. Then, image formation was performed in the following environment.

First, it was confirmed whether or not an image abnormality called black streak appeared in an image formed under each environment. Further, the charging roller in each image forming apparatus after formation under each environment was visually checked for contamination. Then, image abnormalities (black streaks) and dirt on the charging roller were comprehensively evaluated based on the following five evaluation criteria.
Rank 1: Image abnormality (black streak) is not confirmed in both the normal temperature environment and the low temperature environment, and the charging roller after formation is hardly contaminated.
Rank 2: An image abnormality (black streak) is not confirmed in both the normal temperature environment and the low temperature environment, but some contamination is confirmed on the charging roller after formation.
Rank 3: Image abnormality (black streaks) is confirmed in a low-temperature environment, and a slight contamination is confirmed on the formed charging roller.
Rank 4: About 5,000 images in both normal temperature environment and low temperature environment.
Black streaks) appear, and contamination is confirmed on the charged roller after formation, but the degree of image abnormality and contamination is lighter than rank 5.
Rank 5: Image abnormalities (black streaks) exceeding the allowable limit appear on the image from about 5,000 sheets in both the normal temperature environment and the low temperature environment, and the charging roller after the formation is also confirmed to have excessive contamination. .

Next, it was confirmed whether or not an image abnormality such as a white streak-like defect appeared in an image formed under each environment. Further, visual wear and filming were confirmed on the photosensitive drum in each image forming apparatus after formation in each environment. Then, image abnormality, photoconductor drum wear and filming were comprehensively evaluated based on the following five-level evaluation criteria.
Rank 1: Image abnormality (white streaks) is not confirmed in both the normal temperature environment and the low temperature environment, and almost no wear or filming is confirmed on the formed photosensitive drum.
Rank 2: Image abnormality (white streaks) is not confirmed in both the normal temperature environment and the low temperature environment, and no abrasion is confirmed on the formed photosensitive drum, but a slight filming is confirmed on the photosensitive drum.
Rank 3: Image abnormality (white streaks) appears in the image from about 20,000 sheets in both the normal temperature environment and the low temperature environment. No abrasion is confirmed on the formed photosensitive drum, but filming is confirmed on the photosensitive drum.
Rank 4: About 5,000 images in both normal temperature environment and low temperature environment.
White stripes) appear. Wear or filming is confirmed on the formed photosensitive drum. However, the degree of image abnormality, wear, and filming is lighter than rank 5.
Rank 5: Image abnormalities (white streaks) exceeding the allowable range appear from about 5,000 sheets in both the normal temperature environment and the low temperature environment. Excessive wear or filming is confirmed on the formed photosensitive drum.

(Evaluation results)
The evaluation results for the first to ninth examples and the first and second comparative examples described above are shown in Table 1 below.

  As shown in Table 1, in the first and second comparative examples, rank 5 is evaluated, whereas in the first to ninth embodiments, all are ranked 4 or higher. . Thereby, it can be seen that the above-described change in the contact posture of the contact plate 72a is effective in improving the image quality.

  Further, as shown in Table 1, the contact linear pressure is in the range of 0.008 N / cm to 72 N / cm, specifically in the range of 0.01 N / cm to 70 N / cm. In the third to eighth examples, the evaluation results are as follows. That is, in the third to eighth embodiments, the evaluation results are higher than those in the second and ninth embodiments where the contact line pressure is outside the above range. Further, in the fifth to seventh embodiments in which the contact linear pressure is in the range of 1 N / cm or more and 50 N / cm or less, the second to fourth, eighth examples in which the contact linear pressure is out of this range. Compared to the ninth embodiment, the evaluation results are all high. For this reason, the contact linear pressure is preferably 0.008 N / cm or more and 72 N / cm or less, more preferably 0.01 N / cm or more and 70 N / cm or less, and 1 N / cm or more and 50 N / cm or less. It turns out that it is still more preferable.

  Next, an example corresponding to the above-described second embodiment will be described together with a comparative example to be compared with the example.

(Eleventh embodiment)
In the eleventh example, the image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. was modified as in the second embodiment described with reference to FIGS. First, the protective agent leveling member in the protective layer forming apparatus mounted on the image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. was replaced with the protective agent leveling member 211 shown in FIGS. Moreover, the control part 8 and the temperature sensor 9 shown in FIG.4 and FIG.5 were mounted. The contact pressure was “0.1 N / cm” at a high temperature of 15 ° C. or higher, and “30 N / cm” at a low temperature of less than 15 ° C.

  Further, in the eleventh example, as the protective agent, zinc stearate containing boron nitride as inorganic fine particles was used. The compounding ratio (mass ratio) of zinc stearate and boron nitride is “9” for zinc stearate and “1” for boron nitride.

  Except for the protective agent leveling member 211 and the protective agent, the image forming apparatus of the first example was obtained using the components of the image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. as they were.

(Twelfth to 28th Examples)
As described in Table 2 below, the twelfth to twenty-eighth embodiments are the same as the eleventh embodiment except that the contact line pressure is changed in the range of 0.005 N / cm to 85 N / cm. An image forming apparatus was obtained.

(Eleventh comparative example)
In the eleventh comparative example, an image forming apparatus imagio MP C4500 manufactured by Ricoh Co., Ltd. was used as it was. In this image forming apparatus imagio MP C4500, the protective agent leveling member in the protective layer forming apparatus uses a blade like the protective agent leveling member 520 in the conventional protective layer forming apparatus 500 described with reference to FIG. It has become a thing. The leading edge portion is in contact with the outer peripheral surface of the photosensitive drum. That is, in the eleventh comparative example, like the protective agent leveling member 520 in the conventional protective layer forming apparatus 500 described with reference to FIG. 6, the leading edge portion is in the trailing direction on the outer peripheral surface of the photosensitive drum. Abut. However, in the eleventh comparative example, the contact line pressure is adjusted to a constant value of “5 N / cm”.

(12th to 15th comparative examples)
As described in Table 2 below, the images of the twelfth to twenty-eighth examples under the same conditions as the eleventh comparative example, except that the contact line pressure is changed in the range of 10 N / cm to 50 N / cm. A forming device was obtained.

(Evaluation)
In the image forming apparatuses of the 11th to 28th examples and the 11th to 28th comparative examples obtained as described above, the image formation of the 1st to 9th examples, the 1st and 2nd comparative examples described above is performed. Evaluation similar to that of the apparatus was performed.

(Evaluation results)
The evaluation results for the 11th to 28th examples and the 11th to 15th comparative examples described above are shown in Table 2 below.

  As shown in Table 2, in the 11th to 15th comparative examples, rank 5 is evaluated, whereas in the 11th to 28th examples, all are ranked 4 or higher. . Accordingly, it can be seen that the above-described change in the contact pressure of the contact plate 211a is effective in improving the image quality.

  Further, as shown in Table 2, the contact linear pressure is within the range of 0.008 N / cm to 82 N / cm, specifically within the range of 0.01 N / cm to 80 N / cm. In the 11th to 27th examples, the evaluation results are as follows. That is, in the 11th to 27th examples, the evaluation results are higher than those in the 27th and 28th examples in which the contact line pressure is outside the above range. This shows that the contact linear pressure is preferably 0.008 N / cm or more and 72 N / cm or less.

2, 2Y, 2M, 2C, 2K, 200 Process cartridge 3 Photosensitive drum (an example of an image carrier)
3a Photosensitive drum outer peripheral surface (an example of an image forming surface)
4 Charging device (part of an example of image forming unit)
5 Development device (part of an example of image forming unit)
6 Cleaning member 7 Protective layer forming device (part of an example of protective layer forming device)
8 Control unit (sliding member, part of an example of protective layer forming device)
9 Temperature sensor (sliding member, part of an example of protective layer forming device)
30 Optical writing unit (part of an example of image forming unit)
40 Intermediate transfer unit (example of transfer section)
60 fixing device (an example of a fixing unit)
71 protective agent application member (an example of a protective agent application member)
71b Solid protective agent 72, 211 Protective agent leveling member (sliding member, part of an example of protective agent leveling member)
72a, 211a Contact plate (an example of a contact plate)
72b Support part (an example of a support part)
72c Rotating shaft (an example of rotating shaft)
100 Image forming apparatus 211b Support part (part of an example of support part)
211c Contact pressure adjusting part (a part of an example of a support part)

Japanese Patent Laid-Open No. 10-260614 JP 2003-57996 A JP 2002-244485 A JP 2006-154747 A JP 2001-305907 A JP 2006-251751 A JP 2007-264347 A

Claims (17)

It is mounted on an image forming apparatus that forms a toner image on an image forming surface that has a predetermined width and circulates, transfers the toner image to a sheet, and fixes it on the sheet.
Protecting the image forming surface and leveling the protective agent by rubbing the image forming surface coated with a protective agent that imparts lubricity to the image forming surface, and layering the protective agent on the image forming surface In the rubbing member for forming
A contact plate having a strip shape extending substantially parallel to the width direction of the image forming surface, the long edge of which contacts the image forming surface over the entire width in the width direction;
A support portion for supporting the contact plate so that the contact state of the contact plate with the image forming surface can be changed;
A rubbing member comprising:   2. The slide according to claim 1, wherein the support portion supports the contact plate in the contact state so that the contact posture of the contact plate with respect to the image forming surface can be changed. Rub member.   The rubbing member according to claim 2, wherein the support portion supports the abutting plate so as to be rotatable about a rotation shaft extending substantially parallel to the width direction of the image forming surface.   The support portion includes a trailing posture in which the long end edge contacts the image forming surface from the trailing direction, and a counter posture in which the long end edge contacts the image forming surface from the counter direction. The rubbing member according to claim 2, wherein the rubbing member is supported so as to be changeable between. A temperature sensor for measuring an environmental temperature at an installation place of the image forming apparatus or an environmental temperature in the image forming apparatus;
The control part which controls the said support part so that the said contact attitude | position of the said contact plate may be changed according to the environmental temperature measured with the said temperature sensor, From the Claim 2 characterized by the above-mentioned. The rubbing member according to any one of 4.   When the environmental temperature measured by the temperature sensor satisfies a predetermined high temperature condition, the abutting plate is in a trailing posture in which the long edge abuts on the image forming surface from the trailing direction. When the environmental temperature measured by the temperature sensor satisfies a predetermined low temperature condition, the contact plate is supported in a counter posture in which the long edge contacts the image forming surface from the counter direction. The rubbing member according to claim 5, wherein the support portion is controlled as described above.   7. The contact linear pressure of the long end edge of the contact plate against the image forming surface is 0.008 N / cm or more and 72 N / cm or less. 8. The rubbing member as described.   2. The slide according to claim 1, wherein the support portion supports the contact plate so that the contact pressure of the contact plate with respect to the image forming surface can be changed in the contact state. Rub member. A temperature sensor for measuring an environmental temperature at an installation place of the image forming apparatus or an environmental temperature in the image forming apparatus;
9. The apparatus according to claim 8, further comprising a control unit that controls the support unit so that the contact pressure of the contact plate is changed according to an environmental temperature measured by the temperature sensor. The rubbing member as described.   The said control part controls the said support part so that the said contact pressure may become low, when the environmental temperature measured with the said temperature sensor satisfy | fills predetermined high temperature conditions. A rubbing member.   The said control part controls the said support part so that the said contact pressure may become high, when the environmental temperature measured with the said temperature sensor satisfy | fills predetermined low temperature conditions. The rubbing member as described in 2.   12. The contact linear pressure of the long end edge of the contact plate with respect to the image forming surface is 0.008 N / cm or more and 82 N / cm or less. 12. The rubbing member as described. The rubbing member is a protective agent leveling member that leveles the protective agent and forms a layer of the protective agent on the image forming surface;
The rubbing member according to any one of claims 1 to 12, wherein the protective agent is a protective agent containing a fatty acid metal salt as a main component.   The rubbing member according to claim 13, wherein the fatty acid metal salt contains zinc stearate.   The rubbing member according to claim 13 or 14, wherein the protective agent contains a fatty acid metal salt and inorganic fine particles. Mounted on an image forming apparatus that forms a toner image on an image forming surface having a predetermined width and circulates, transfers the toner image onto a sheet, and fixes the image on the sheet. The image forming surface is mounted on the image forming surface. In a protective layer forming apparatus for forming a layer of a protective agent that protects and imparts lubricity to the image forming surface,
A protective agent applying member for applying the protective agent to the image forming surface;
A protective agent leveling member that rubs the image forming surface on which the protective agent has been applied by the protective agent application member, leveles the protective agent, and forms a layer of the protective agent on the image forming surface; Prepared,
The protective layer forming apparatus, wherein the protective agent leveling member is a rubbing member according to any one of claims 1 to 15. An image carrier having an image forming surface that circulates and has a predetermined width, an image forming unit that forms a toner image on the image forming surface, a transfer unit that transfers the toner image onto a sheet, and the toner image that is transferred to a sheet The image forming surface is rubbed against the fixing portion for fixing to the image forming surface and the image forming surface coated with a protective agent for providing lubricity to the image forming surface, and the protective agent is leveled to form the image. In an image forming apparatus comprising a protective agent leveling member that forms a layer of the protective agent on a surface,
16. The image forming apparatus according to claim 1, wherein the protective agent leveling member is a rubbing member according to any one of claims 1 to 15.

Images