JP2007086440A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having an intermediate transfer body to which a toner image formed by an electrophotographic system is transferred, the image forming apparatus being devised so as to satisfactorily retain for a long time cleaning performance for the intermediate transfer body using the cleaning blade and be suitable to reduce its size. <P>SOLUTION: The image forming apparatus includes: the intermediate transfer body 30 moved in circle in a predetermined direction and used to transfer a toner image, transferred to its surface 30a from an image carrier 11, to a recording medium P; an elastic cleaning blade 72 whose leading edge 721 is pressed against the surface 30a of the intermediate transfer body 30 after the transfer of the toner image to the recording medium P, thereby scraping residual matter from the surface 30a; and accumulating members 73 and 74 receiving the residual matter scraped from the surface 30a of the intermediate transfer body by the cleaning blade 72, and defining a specific space S for accumulating the residual matter scraped after spread upstream from the leading edge 721 in the direction of movement of the intermediate transfer body 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer that includes an intermediate transfer member that receives a transfer of a toner image formed using an electrophotographic system.

  In recent years, as an image forming apparatus for a color printer and a color copying machine using an electrophotographic system, a type employing an intermediate transfer system is increasing. A color image forming apparatus employing this intermediate transfer method forms, for example, toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K) on the surface of the photoreceptor, These toner images are superimposed (primary transfer) on an endless intermediate transfer belt that circulates from the surface of the photoreceptor, and the toner image superimposed on the intermediate transfer belt is transferred (secondary transfer) to a recording medium and fixed. To do.

  By the way, in the primary transfer in which the toner image is transferred from the surface of the photosensitive member to the intermediate transfer belt, not all the toner on the surface of the photosensitive member is transferred to the intermediate transfer belt. Various residues including untransferred toner exist on the body surface. Therefore, in order to remove these residues from the surface of the photoconductor, a technique for mechanically scraping the residue from the surface of the photoconductor by bringing the edge of the cleaning blade having a plate-like elasticity into pressure contact with the surface of the photoconductor is known. (See, for example, Patent Document 1).

  Also, when transferring the toner image from the intermediate transfer belt to the recording medium, not all the toner on the intermediate transfer belt is transferred to the recording medium. As with the body surface, there are various residues including untransferred toner. Accordingly, a technique for removing these residues from the intermediate transfer belt has been proposed. As a cleaning method for removing residual toner from the intermediate transfer belt, a method of removing a residual toner from the surface of the intermediate transfer belt by applying a bias to the conductive brush fiber and electrostatically adsorbing the residual toner to the brush fiber (for example, , See Patent Document 2).

  However, in this electrostatic cleaning method, the residual toner adsorbed on the brush fibers must be collected from the brush fibers, and a collecting member is required, leading to an increase in the size and cost of the apparatus. In addition, a power source for applying a bias to the brush fibers is required, which also leads to an increase in size and cost of the apparatus. Furthermore, external additive particles smaller than the toner base particles are attached to the surface of the toner base particles of the toner used for forming the toner image, and these residues on the intermediate transfer belt include these External additive particles are also included. Since the external additive particles are smaller than the toner base particles, it is difficult to carry electric charge, and it is difficult to adsorb electrostatically like the residual toner. The electrostatic cleaning method removes external additive particles. Can not do it.

  By the way, since the technique using the cleaning blade described above as the technique for cleaning the surface of the photosensitive member is a technique for mechanically cleaning the object to be cleaned, it is possible to remove external additive particles, and to reduce the size of the apparatus. It is a suitable low cost technology. However, rubbing occurs between the edge of the cleaning blade pressed against the object to be cleaned and the object to be cleaned, and if this rubbing is not properly maintained, the edge of the blade is worn or worn. Chipping or peeling occurs, making it difficult to maintain good cleaning properties over a long period of time. Therefore, in a technique using a cleaning blade, a cleaning object that does not have a very high frictional force with the edge of the blade tip is suitable. Here, when comparing the photoconductor and the intermediate transfer belt, both are made of various materials, but the intermediate transfer belt has a frictional force with the edge of the blade tip compared to the photoconductor. It tends to be high.

Conventionally, as a technique for trying to maintain the cleaning characteristics of the intermediate transfer belt surface having a Young's modulus in the range of 0.5 GPa or more and 1.5 GPa or less with a cleaning blade well over a long period of time, a cooling aid is used as an external additive particle. A technique has been proposed in which the cooling aid is supplied to the edge of the front end of the cleaning blade that is adhered to the toner base particles and pressed against the surface of the intermediate transfer belt (see Patent Document 3).
JP 11-161125 A JP 2002-207403 A JP 2003-140468 A

  However, in the technique described in Patent Document 3, when a toner image having a low image density is transferred to the intermediate transfer belt, the cleaning aid is not supplied to the edge of the blade, and the tip of the blade is not transferred. Wear, cracks or creaking will occur at the edges. Further, in a soft intermediate transfer belt having a surface Young's modulus of less than 0.5 GPa, there is a risk that abrasion, chipping, or the like may occur at the edge of the tip of the blade. Furthermore, it is conceivable to apply the cleaning aid directly to the intermediate transfer belt, but this requires a coating device, which increases the size of the device.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus suitable for miniaturization in which the cleaning property of an intermediate transfer member using a cleaning blade is favorably maintained over a long period of time.

The image forming apparatus of the present invention that solves the above object forms a toner image on the surface of an image carrier, and finally transfers and fixes the toner image on the recording medium, thereby fixing the toner image on the recording medium. In an image forming apparatus for forming an image
An intermediate transfer member that circulates and moves in a predetermined direction, transfers the toner image from the image carrier to the surface, and transfers the transferred toner image to a recording medium;
A cleaning blade having elasticity that the edge of the tip is pressed against the surface of the intermediate transfer member after the toner image is transferred to the recording medium, and the residue remaining on the surface is scraped off from the surface;
Residue that receives the residue scraped off from the surface of the intermediate transfer member by the cleaning blade, spreads from the edge of the tip to the upstream side in the moving direction of the intermediate transfer member, and defines a predetermined space for retaining the scraped residue. And a member.

  According to the image forming apparatus of the present invention, the residue stays in the predetermined space, and particles having a small particle diameter in the staying residue are formed between the surface of the intermediate transfer member and the edge of the tip of the cleaning blade. It penetrates in between and functions as a lubricant, and it is possible to suppress the occurrence of wear, chipping or cracking at the edges. Moreover, even when the transfer of the toner image having a low image density continues to the intermediate transfer member, since the residue remains in the predetermined space, the lubricant is applied to the edge of the tip of the cleaning blade. The supply of functioning particles is not cut off, and it is possible to suppress the occurrence of wear, chipping or the like at the edges. Therefore, in the image forming apparatus of the present invention, the cleaning property of the intermediate transfer member using the cleaning blade is well maintained over a long period of time. Further, the provision of the staying member does not lead to an increase in the size of the apparatus.

  In the image forming apparatus of the present invention, the intermediate transfer member preferably has a Young's modulus value on the surface of the intermediate transfer member in a range of 1 MPa to 1.5 GPa.

  According to the image forming apparatus of the present invention, even when the intermediate transfer member has a soft surface, it is possible to suppress the occurrence of wear or chipping at the edge of the tip of the cleaning blade, but the surface Young's modulus is 1 MPa. The lower intermediate transfer member has a rubber-like surface and becomes too viscous to increase the coefficient of friction. For this reason, the stress applied to the edge of the tip of the cleaning blade increases, which is not preferable.

  By the way, columnar conductive foreign matters such as aluminum powder and carbon fiber may be present on the surface of the intermediate transfer member due to piercing the surface, and when the intermediate transfer member receives the transfer from the image carrier, If it is pressed against the image carrier, the conductive foreign matter present on the surface of the intermediate transfer member pierces the image carrier by the pressing force. If the image carrier is charged with the conductive foreign matter pierced, a color point is generated on the formed image. According to the image forming apparatus of the present invention, the residue staying in the predetermined space is stirred in the predetermined space. The conductive foreign matter present on the surface of the intermediate transfer member is considerably removed from the surface of the intermediate transfer member by rubbing with the residue stirred in the predetermined space, and this conductive foreign matter is pierced into the image carrier. Since the harder the intermediate transfer member, the more easily the intermediate transfer member, the surface of the intermediate transfer member preferably has a Young's modulus of 1.5 GPa or less.

  Here, the intermediate transfer member may be an endless intermediate transfer belt.

In the image forming apparatus according to the aspect of the invention, it is also preferable that the cleaning blade has a 300% modulus value at the edge of the tip in a range of 70 kgf / cm ^{2 to} 150 kgf / cm ² .

If the value of the 300% modulus at the edge of the tip is less than 70 kgf / cm ² , the edge of the tip of the cleaning blade is too soft, and the intermediate transfer member that circulates may be pulled in the downstream in the moving direction, causing it to become chipped. In addition, there are times when it gets mekre. On the other hand, when the value is higher than 150 kgf / cm ² , the edge is too hard, and this may also be broken.

  Furthermore, in the image forming apparatus of the present invention, the intermediate transfer member receives a transfer of a toner band extending in the extending direction of the central axis when the intermediate transfer member circulates on the surface of the intermediate transfer member. An embodiment is also preferred in which the toner band that has been transferred is allowed to reach the edge of the tip of the cleaning blade without being transferred to the recording medium.

  When an unused (new) image forming apparatus performs image formation for the first time, the predetermined space is empty. Therefore, the toner band is formed before the image is formed, and the toner band reaches the edge of the tip of the cleaning blade without being transferred to the recording medium by the intermediate transfer member, so that the toner band becomes the cleaning blade. Is scraped off from the surface of the intermediate transfer member, and the toner or the like constituting the toner band stays in the predetermined space. As a result, particles functioning as a lubricant are supplied from the first image formation to the edge of the tip of the cleaning blade.

  Further, the intermediate transfer belt receives the transfer of the toner band regularly or irregularly even after the use of the image forming apparatus is started, and the cleaning belt remains untransferred to the recording medium. The blade may reach the edge of the tip of the blade.

Further, in the image forming apparatus of the present invention, the cleaning blade is disposed with the edge of the tip facing downward,
A seal member for receiving the residue scraped off from the surface of the intermediate transfer member by the cleaning blade; and a blocking member extending to a position higher than the height of the edge of the tip of the cleaning blade. It is also preferable to have it.

  The blocking member is wrapped with the tip portion of the cleaning blade, and the residue staying in the predetermined space is reliably supplied to the edge of the tip of the cleaning blade.

Furthermore, in the image forming apparatus of the present invention, the blocking member has an opening,
More preferably, the image forming apparatus further includes a housing that is connected to the predetermined space through the opening and stores the residue that has flowed through the opening and stayed in the predetermined space.

  When the residue staying in the predetermined space becomes excessively compacted in the predetermined space, the particles in the residue staying in the predetermined space are separated from the surface of the intermediate transfer member and the edge of the tip of the cleaning blade. The residue staying in the predetermined space flows out from the predetermined space through the opening of the blocking member, so that the residue staying in the predetermined space becomes the predetermined space. It is possible to suppress an excessively compacted state in the space.

  Still further, in the image forming apparatus according to the present invention, the blocking member allows an upward passage of the residue staying in the predetermined space between the end of the cleaning blade and the edge of the cleaning blade. It is a more preferable aspect that the gap extends to a position higher than the height position of the edge of the tip.

  According to this aspect, the residue staying in the predetermined space gradually overflows from the predetermined space through the interval in addition to the opening, and the predetermined space becomes a suitable consolidated state. .

  According to the present invention, it is possible to provide an image forming apparatus suitable for miniaturization in which the cleaning property of the intermediate transfer member using the cleaning blade is favorably maintained over a long period of time.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus 1 of the present embodiment is an image forming apparatus that employs a full-color tandem system, and has a full-color mode and a monochrome mode. These two modes are set by the user operating an operation panel (not shown). When the full color mode is set, the image forming apparatus shown in FIG. 1 uses four toner image forming units corresponding to the four color toners of black, cyan, magenta, and yellow to feed the intermediate transfer belt. The toner image forming units form respective color toner images in synchronization with each other, and the toner images are superimposed on an intermediate transfer belt as an intermediate transfer member (primary transfer), and are superimposed on the intermediate transfer belt. The toner image is transferred (secondary transfer) to a sheet as a recording medium and fixed. On the other hand, when the monochrome mode is set, the image forming apparatus shown in FIG. 2 uses only the toner image forming unit corresponding to the black (K) toner among the four toner image forming units to generate a black toner image. Then, the black toner image is secondarily transferred onto a sheet through a primary transfer onto an intermediate transfer belt and fixed.

  An image forming apparatus 1 shown in FIG. 1 is supported by four toner image forming units 10K, 10C, 10M, and 10Y, four primary transfer rolls 20, and three support rolls 31 so as to circulate in a counterclockwise direction. A semiconductive intermediate transfer belt 30, a batch transfer device 40 that performs secondary transfer, and a fixing device 50 that fixes an unfixed toner image on a sheet are provided.

  The intermediate transfer belt 30 shown in FIG. 1 is an endless belt having elasticity made of a rubber material. The intermediate transfer belt 30 is a belt whose surface (outer peripheral surface) is quite soft.

  The four toner image forming units 10K, 10C, 10M, and 10Y perform intermediate transfer in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the moving direction of the intermediate transfer belt 30. The belt 30 is arranged side by side in the moving direction. That is, the black toner image forming unit 10 is positioned at the most upstream in the moving direction of the intermediate transfer belt 30. Each toner image forming unit 10 includes a drum-shaped photoconductor 11 that rotates clockwise. As the photoconductor 11 rotates about the rotation axis, the surface of the photoconductor 11 circulates around the rotation axis. The surface of the photoreceptor 11 is in contact with the intermediate transfer belt 30. In a region where the intermediate transfer belt 30 is in contact with the surface of the photoconductor 11, a primary transfer roll 20 is provided so as to sandwich the intermediate transfer belt 30 with the photoconductor 11, and this region is a primary transfer region.

  Here, FIG. 2 will be used together with FIG. 1 to further explain the image forming apparatus of this embodiment.

  FIG. 2 is a diagram showing in more detail the toner image forming unit of black toner arranged at the most upstream in the moving direction of the intermediate transfer belt among the four toner image forming units shown in FIG.

  The toner image forming unit 10K of black toner shown in FIG. 2 includes a charger 12, an exposure device 13, a developing device 14, a cleaning device 15, and a static eliminator 16 in addition to the photoreceptor 11.

  The remaining three-color toner image forming units 10C, 10M, and 10Y have the same configuration as that of the black toner image forming unit 10K shown in FIG.

The charger 12 includes a charging roll 121 that rotates in contact with the surface of the photoconductor 11, and a charger power supply 122 that supplies power to the charging roll 121. The charger power supply 122 applies a charging bias obtained by superimposing an AC voltage on a DC voltage to the charging roll 121. The charging roll 121 is a semiconductive one that rotates in contact with the photoconductor 11, and charges the photoconductor 11 by generating a discharge in a minute gap near the contact portion with the photoconductor 11. Instead of the charging roll 121, a blade-shaped charging member, a belt-shaped charging member, a brush-shaped charging member, a magnetic brush-shaped charging member, or the like can be applied. Further, the charging roll 121 and the blade-shaped charging member are not limited to the contact state with respect to the photoconductor 11, and may be arranged in a close state having a certain amount of gap (100 μm or less). A roll-shaped charging member, a blade-shaped charging member, and a belt-shaped charging member are composed of a material adjusted to an electric resistance (10 ³ Ω to 10 ⁸ Ω) effective as a charging member, and are a single layer. Or you may comprise from several layers. The material is mainly composed of synthetic rubber such as urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM, epichlorohydrin rubber, and elastomers such as polyolefin, polystyrene, vinyl chloride, conductive carbon, metal oxide, ion An appropriate amount of an optional conductivity imparting agent such as a conductive agent can be blended to develop and use an effective electrical resistance as a charging member. Furthermore, a resin such as nylon, polyester, polystyrene, polyurethane, silicone, etc. is made into a paint, and an appropriate amount of any conductivity imparting agent such as conductive carbon, metal oxide, ionic conductive agent, etc. is blended there, and the resulting paint is dipped. They can be laminated and used by any method such as spraying or roll coating. The charging method described here is a contact charging method, but a corotron charging method which is a non-contact charging method may be adopted.

  The exposure device 13 irradiates exposure light based on image information toward the photoreceptor surface 11a. The developing device 14 is disposed on the upstream side of the primary transfer region around the photoreceptor 11. The developing device 14 includes a developer container 141 that contains a developer containing toner and a carrier, and a developer that carries the toner contained in the developer container 141 and rotates while facing the surface 11a of the photoreceptor. It has a roll 142. The toner contained in the developer contained in the developer containing body 141 is such that external additive particles smaller than the toner mother particles such as a lubricant, a transfer aid, and a cleaning aid adhere to the surface of the toner mother particles. Yes, and has a charging characteristic of charging the negative electrode. The static eliminator 16 is disposed on the downstream side of the primary transfer region around the photoconductor 11, and neutralizes residual charges on the surface 11 a that has passed through the primary transfer region of the photoconductor 11.

  When image formation is performed in the image forming apparatus 1 shown in FIG. 1, the surface 11 a of the photoconductor 11 is uniformly charged by a discharge phenomenon by the charger 12 and then exposed based on image information by the exposure device 13. Light is irradiated to form an electrostatic latent image on the photoreceptor surface 11a. Subsequently, toner is supplied from the developing roll 142 to the photoreceptor surface 11a on which the electrostatic latent image is formed, and the electrostatic latent image is developed with toner, so that a toner image is formed on the photoreceptor surface 11a. Each of the four primary transfer rolls 20 is applied with a primary transfer bias of a positive polarity having a polarity opposite to the charged polarity of the toner from a primary transfer power source 21, and the toner formed on the photoreceptor surface 11. The image moves from the photoreceptor surface 11a to the surface 30a of the intermediate transfer belt 30 in the primary transfer region.

  In the full color mode, each toner image forming unit 10K, 10C, 10M, 10Y forms a color toner image on the surface 11a of the rotating photoconductor 11, and each color toner image is superimposed on the intermediate transfer belt surface 30a. Become a statue.

  On the other hand, in the monochrome mode, toner image formation is not performed in the remaining three toner image forming units 10C, 10M, and 10Y except for the black toner image forming unit 10K among the four toner image forming units. A black toner image is formed only by the image forming unit 10K, and the black toner image is carried on the surface 30a of the intermediate transfer belt that circulates and moves. Here, when the photoreceptor 11 on which the toner image is not formed stops rotating in a state where the intermediate transfer belt 30 is circulated, the frictional force with the intermediate transfer belt 30 that circulates increases, and the surface of the photoreceptor 11 Scratches and unnecessary wear will occur in 11a. For this reason, the photoconductor 11 on which the toner image is not formed continues to rotate.

  The batch transfer device 40 includes a secondary transfer roll 41 disposed in pressure contact with the toner image carrying surface side of the intermediate transfer belt 30 and a backup roll 42 disposed on the back side of the intermediate transfer belt 30. The intermediate transfer belt 30 is sandwiched between two rolls 41 and 42. A space between these two rolls 41 and 42 becomes a secondary transfer region.

  Further, the image forming apparatus 1 shown in FIG. 1 is provided with a paper tray 60, and the paper P accommodated in the paper tray 60 is sent out from the paper tray 60 by the feed roll 61, and is secondary at a predetermined timing. It is sent to the transfer area. In other words, in the full color mode, the paper P is fed to the secondary transfer area in accordance with the timing at which the overlapping toner images on the intermediate transfer belt 30 reach the secondary transfer area. In the monochrome mode, the intermediate transfer is performed. The paper P is fed into the secondary transfer area in accordance with the timing at which the black toner image carried on the belt 30 reaches the secondary transfer area.

  Secondary transfer baice is applied to the secondary transfer roll 41, and the toner image on the intermediate transfer belt 30 is transferred onto the fed paper P in the secondary transfer region.

  The fixing device 50 includes a fixing roll 51 having a heating and heating mechanism 511 and a pressure roll 52 provided so as to face the fixing roll 51. Between the fixing roll 51 and the pressure roll 52 facing each other, the paper P that has passed through the secondary transfer region is conveyed. The toner constituting the toner image on the paper P is melted by the heating mechanism 511 of the fixing roll 51 and is fixed to the paper P by receiving pressure from the pressure roll 52.

  A belt cleaner 70 is provided on the downstream side of the batch transfer device 40. Residues such as residual toner that could not be transferred to the paper P exist on the surface 30a of the intermediate transfer belt 30 that has passed through the secondary transfer region. A belt cleaner 70 shown in FIG. 1 is an apparatus for removing these residues, and is disposed at a position downstream of the secondary transfer region in the intermediate transfer belt moving direction. Here, the description of the belt cleaner 70 shown in FIG. 1 will be continued with reference to FIG.

  FIG. 3 is a view of a part of the cleaning device shown in FIG. 1 as viewed from one end side of the central axis when the intermediate transfer belt circulates.

  A belt cleaner 70 shown in FIG. 3 includes a housing 71, a cleaning blade 72, a lower seal 73, and a blocking member 74. The cleaning blade 72 has a rectangular shape that is long in the direction perpendicular to the paper surface of FIG. 3 (the direction in which the central axis of the intermediate transfer belt 30 extends). Here, one end in the short direction is the tip. The other end is called the rear end. Further, the lower seal 73 and the blocking member 74 are also in a rectangular shape elongated in a direction perpendicular to the paper surface of FIG. The lower seal 73 and the blocking member 74 are longer than the cleaning blade 72 in a direction perpendicular to the paper surface of FIG.

  The cleaning blade 72 is directed downstream with respect to a vertical line that rises perpendicularly from the surface 30a of the intermediate transfer belt 30 with its front end facing the surface 30a of the intermediate transfer belt 30 that has passed through the secondary transfer region. It is deployed by a doctor method that leans to the side. The cleaning blade 72 is made of urethane rubber having a thickness of 2 mm, the rear end is fixed to the housing 71 by bonding or screwing, and the edge portion 721 at the front end is pressed against the surface 30 a of the intermediate transfer belt 30. Has been. When the intermediate transfer belt 30 circulates in a predetermined direction, the residue remaining on the surface 30a that has passed through the secondary transfer region of the intermediate transfer belt 30 is scraped from the surface 30a by the leading edge portion 721 of the cleaning blade 72. Be dropped. The contact angle of the cleaning blade 72 shown in FIG. 3 with respect to the intermediate transfer belt surface 30a is 22 °. The contact angle referred to here is an angle between the cleaning blade 72 and the surface 30a of the intermediate transfer belt 30 that extends from the portion where the cleaning blade 72 is in pressure contact to the downstream side in the moving direction of the intermediate transfer belt.

  As shown in FIG. 3, the bottom wall 711 of the housing 71 is provided with an upright portion 712 that rises upward. The upright portion 712 is at a position spaced from the surface 30 a of the intermediate transfer belt 30 and at a position below the leading edge portion 721 of the cleaning blade 72. Both the lower seal 73 and the blocking member 74 are film members made of a resin material, and the lower ends thereof are fixed to the rising portions 712 by bonding or screwing. The housing 71 is provided with a discharge port (not shown), and a transport auger 713 is provided inside the housing 71.

  The blocking member 74 shown in FIG. 3 is a polyethylene terephthalate (PET) resin sheet having a thickness of 50 μm, and the height position of the upper end 741 is higher than the height position of the edge portion 721 of the cleaning blade 72. That is, a lap region L is formed between the blocking member 74 and the tip portion of the cleaning blade 72. Further, the blocking member 74 fixed to the rising portion 712 has a single opening 742 in the vicinity of the rising portion 712. The opening 742 is a rectangular long hole provided along the longitudinal direction of the blocking member 74 and is connected to the inside of the housing 71. The blocking member 74 may be provided with a plurality of openings.

  The lower seal 73 is a polyurethane resin sheet having a thickness of 20 μm. A gap is provided between the upper end 731 of the lower seal 73 and the leading edge portion 721 of the cleaning blade 72, and the upper end 731 of the lower seal 73 is pressed against the intermediate transfer belt surface 30a. That is, the lower seal 73 connects the upright portion 712 and the intermediate transfer belt surface 30a that are spaced apart from the intermediate transfer belt surface 30a at a position below the leading edge portion 721 of the cleaning blade 72. The length of the central axis of the intermediate transfer belt 30 of the lower seal 73 in the extending direction (length in the longitudinal direction) is approximately the same as the length of the blocking member 74 in the longitudinal direction. The lower seal 73 receives the residue scraped off by the cleaning blade 72.

  As shown in FIG. 3, in a space extending from the leading edge portion 721 of the cleaning blade 72 to the upstream side in the movement direction of the intermediate transfer belt 30, a part of the intermediate transfer belt surface 30a, a lower seal 73, a blocking member 74, and the residue T scraped off by the cleaning blade 72 stays in this space S. That is, the combination of the lower seal 73 and the blocking member 74 corresponds to an example of a staying member according to the present invention. Lubricant particles and toner having a small particle diameter contained in the residue T staying in the space S enter between the intermediate transfer belt surface 30a and the leading edge portion 721 of the cleaning blade 72, and the lubricant. As a result, it is possible to prevent the tip edge portion 721 from being worn, chipped, or scratched. In addition, even when the transfer of the toner image having a low image density continues to the intermediate transfer belt 30, since the residue remains in the space S, the lubricant to the leading edge portion 721 of the cleaning blade 72 is retained. As a result, the supply of the particles functioning as “s” is not cut off, and the tip edge portion 721 is prevented from being worn or chipped. Therefore, in the image forming apparatus 1 shown in FIG. 1, the cleaning performance of the intermediate transfer belt 30 using the cleaning blade 72 is well maintained over a long period of time. Further, even if the lower seal 73 and the blocking member 74 are provided, the apparatus is not enlarged. Further, the residue T staying in the space S is stirred in the space S. In some cases, a columnar conductive foreign material such as aluminum powder or carbon fiber is stuck on the surface 30a of the intermediate transfer belt surface 30a. When the conductive foreign matter existing on the surface 30a of the intermediate transfer belt pierces the photoconductor 11 in the primary transfer region, and the photoconductor 11 is charged with the conductive foreign matter stuck, a color point is generated on the formed image. However, in this embodiment, the conductive foreign matter present on the intermediate transfer belt surface 30a is removed from the surface 30a by rubbing with the residue stirred in the space S. For this reason, generation | occurrence | production of the color point resulting from an electroconductive foreign material is also suppressed.

  Next, the operation of the lower seal 73 and the blocking member 74 will be described. As shown in FIG. 3, the leading edge portion 721 of the cleaner blade 72 and the upper end 731 of the lower seal 73 are pressed against the intermediate transfer belt surface 30a to be deformed toward the housing 71, and the elasticity thereof makes contact with the intermediate transfer belt surface 30a. Adhesion is maintained. Although the blocking member 74 is in contact with the back side of the tip portion of the cleaning blade 72 in the initial state, when the residue T scraped off from the intermediate transfer belt surface 30a is retained in the space S, the pressing force is applied. A gap G is formed by deforming backward with Pt. The gap G allows the residue T staying in the space S to pass upward. FIG. 3 shows a state in which the gap G is formed. The blocking member 74 shown in FIG. 3 stays in the space S between the tip edge portion 721 of the cleaning blade 72. The residue T extends to a position higher than the height position of the tip edge portion 721 of the cleaning blade 72 with an interval that allows the residue T to pass upward. The residue T staying in the space S passes through the gap G, gets over the upper end 741 of the blocking member 741, and gradually overflows into the housing 71.

  In addition, since the wrap region L is provided between the blocking member 74 and the tip portion of the cleaning blade 72, particles functioning as a lubricant in the residue T staying in the space S are removed from the cleaning blade. 72 is always supplied to the leading edge portion 721 of the 72. The length of the wrap region L is about 1.5 mm in this embodiment.

  The material and thickness of the blocking member 741 and the dimension of the wrap region L are not limited to the above example. In short, the residue T is appropriate in the predetermined space S so as to cover at least the tip edge portion 721 of the cleaner blade 72. It is only necessary to determine that the gap G is formed and the residue T can gradually move into the housing 71 through the gap G when the amount of stay is increased. These numerical values can be determined experimentally.

  On the other hand, the housing 71 is connected to the space S through an opening 742 in the vicinity of the upright portion 712 provided in the blocking member 74, and the density of the residue T remaining in the space S is higher than that of the toner. Large carriers, paper dust, or conductive foreign matter removed from the intermediate transfer belt surface 30 flows into the inside of the housing 71 through the opening 742. When the residue T staying in the space S becomes excessively compacted in the space S, particles functioning as a lubricant in the residue T staying in the space S are cleaned with the intermediate transfer belt surface 30a. Although it is difficult to enter between the leading edge portion 721 of the blade 72, the residue T staying in the space S flows out from the space S through the opening 742 provided in the blocking member 74. Thus, it is possible to suppress the residue T staying in the space S from being excessively consolidated in the space S. In addition, it is possible to prevent conductive foreign matter and the like from entering between the intermediate transfer belt surface 30a and the leading edge portion 721 of the cleaning blade 72, and the leading edge portion 721 can be prevented from being damaged. If the area of the single opening 742 is too large relative to the area of the blocking member 74, the amount of the residue T that enters the inside of the housing 71 through the opening 742 increases, and the leading edge portion of the cleaning blade 72 There arises a problem that 721 is not covered with the residue T. For this reason, it is necessary to determine the shape and size of the opening 742 so that this defect does not occur.

  The housing 71 temporarily stores the residue T that has passed over the blocking member 74 or has flowed through the opening 742. The residue T stored in the housing 71 is stored in the housing 71 by the auger 20 for conveyance. It is pushed to one side and is discharged from a discharge port (not shown).

  Note that side seals (not shown) may be disposed on both sides of the cleaning blade 72. This side seal has a function of preventing the residue scraped off by the cleaning blade 72 from leaking from the lateral direction. For this side seal, a wool base material having a surface layer formed of a fluororesin felt is suitable. Further, the blocking member 74 is preferably long enough to have a slight gap (1-2 mm) between the side seals.

  Further, the image forming apparatus 1 shown in FIG. The control unit 80 controls the entire image forming apparatus 1 shown in FIG. 1. Here, control related to the toner band will be described. The toner band here is a belt-like toner image extending in the extending direction of the rotating shaft 110 of the photoconductor 11, and when transferred to the intermediate transfer belt surface 30a, the intermediate transfer belt 30 is circulated and moved. Becomes a belt-like toner image extending in the extending direction of the central axis. When an unused (new) image forming apparatus performs image formation for the first time, the space S is empty. Therefore, the control unit 80 shown in FIG. 1 first forms the toner band on the photosensitive member surface 11a before image formation. The intermediate transfer belt 30 receives the transfer of the toner band on the surface 30a thereof while being circulated, and the transferred toner band passes through the secondary transfer region. At this time, the secondary transfer roll 41 is in a state in which the secondary transfer baice is not applied, and the intermediate transfer belt 30 does not transfer the toner band onto the paper P, and is applied to the leading edge 721 of the cleaning blade 72 shown in FIG. To reach. The toner band that has reached the leading edge 721 of the cleaning blade 72 is scraped off from the surface 30a of the intermediate transfer belt by the cleaning blade 72, and the toner and the like constituting the toner band stay in the space S. By doing so, particles functioning as a lubricant are supplied from the first image formation to the leading edge portion 721 of the cleaning blade 72. The space S may be filled in advance with particles that function as a lubricant at the factory shipment stage.

  Further, even after the use of the image forming apparatus 1 is started, the toner band may reach the leading edge portion 721 of the cleaning blade 72 without being transferred onto the paper P regularly or irregularly.

  Next, the cleaning blade 72 shown in FIG. 3 will be described in detail. As the material of the cleaning blade 72, a rubber elastic body such as urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber or the like can be used. Among them, it is preferable to use a polyurethane elastic body because of its excellent wear resistance. As the polyurethane elastic body, a polyurethane generally synthesized through an addition reaction between an isocyanate and a polyol and various hydrogen-containing compounds is used. As a polyol component, a polyether-based polyol such as polypropylene glycol or polytetramethylene glycol, Polyester polyols such as adipate polyols, polycaprolactam polyols, polycarbonate polyols, etc., and polyisocyanate components such as tolylene diisocyanate, 4,4′diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, toluidine diisocyanate, etc. Polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclo It is manufactured by preparing a urethane prepolymer using an aliphatic polyisocyanate such as xylmethane diisocyanate, adding a curing agent to the urethane prepolymer, pouring it into a predetermined mold, crosslinking and curing, and then aging at room temperature. ing. As the curing agent, a dihydric alcohol such as 1,4-butanediol and a trihydric or higher polyhydric alcohol such as trimethylolpropane or pentaerythritol are usually used in combination.

The physical properties of the cleaning blade 72 include a 300% modulus (kgf / cm ² ) in the range of 70 to 150. In the cleaning blade 72 shown in FIG. 3, the value of 300% modulus at the leading edge portion 721 is within the above range. If the value of the 300% modulus at the leading edge portion 721 is less than 70 kgf / cm ² , the leading edge portion 721 is too soft and may be pulled down to the downstream side in the moving direction of the intermediate transfer belt 30 that circulates, May be messed up. On the other hand, if the value is higher than 150 kgf / cm ² , the tip edge portion 721 is too hard, and this may also be broken. Further, as the physical properties of the cleaning blade 72, the hardness (JISA scale) is 50 to 90, the Young's modulus (MPa) is 3.92 MPa to 9.8 MPa, the 100% modulus (kgf / cm ² ) is 20 to 65, Strength (kg / cm ² ) is 240 or more and 500 or less, Elongation (%) is 290 or more and 500 or less, Rebound resilience (%) is 30 or more and 70 or less, Tear strength (kg / cm ² ) is 25 or more and 75 or less, The permanent elongation (%) is 4.0 or less.

  The pressure contact force of the cleaning blade 72 is preferably 10 or more and 60 or less (gf / cm), and the contact angle is preferably 17 to 30 (°).

  Further, residual toner that could not be transferred to the surface of the intermediate transfer belt 30 in the primary transfer region also exists on the surface 11a of the photoconductor 11 shown in FIG. 2 that has passed through the primary transfer region. There are also discharge products and the like generated by the discharge phenomenon by the charger 12. A cleaning device 15 shown in FIG. 2 is a device for removing foreign matters such as residual toner and discharge products, and is located downstream of the primary transfer region in the photosensitive member rotation direction and more sensitive than the charger 12. It is deployed at a position upstream of the body rotation direction. The cleaning device 15 includes a cleaning blade 151 and a transfer auger 152. The cleaning blade 151 shown in FIG. 2 has a rectangular shape that is long in the direction perpendicular to the paper surface of FIG. 2 (the direction in which the rotating shaft 110 of the photoconductor 11 extends). As in the case of the cleaning blade 72 shown, one end in the short direction is referred to as a tip. The cleaning blade 151 shown in FIG. 2 has a leading edge portion 1511 pressed against the photoreceptor surface 11a. Residue remaining on the photoreceptor surface 11 is scraped off from the photoreceptor surface 11a by the leading edge portion 1511. More specifically, the residual toner remaining on the photosensitive member surface 11 is dammed by the leading edge portion 1511, and the photosensitive member surface 11a is also polished by the damped residual toner and is applied to the photosensitive member surface 11a. Adhered foreign matter (such as discharge products) is also removed from the photoreceptor surface 11a. The residue removed from the photoreceptor surface 11 a in this way is transported out of the cleaning device 15 by the transport auger 152.

  Here, when the monochrome mode is performed, as described above, the black toner image is formed only by the black toner image forming unit 10K among the four toner image forming units, and the remaining three toner image forming units are used. The photoreceptors 11 of 10C, 10M, and 10Y continue to idle. According to the image forming apparatus 1 shown in FIG. 1, the black toner image forming unit 10K, which is the only toner image forming unit in the monochrome mode, is positioned at the most upstream in the moving direction of the intermediate transfer belt. The black toner image passes through the primary transfer regions of the remaining three toner image forming units 10C, 10M, and 10Y located downstream of the toner image forming unit 10K. The black toner image on the intermediate transfer belt 20 comes into contact with the respective photoreceptor surfaces 10 of these three toner image forming units 10C, 10M, and 10Y. When the black toner image is transferred to the intermediate transfer belt 30, a positive primary transfer bias is applied to the primary transfer roll 20 facing the photoreceptor 11 of the black toner image forming unit 10K. The peeling discharge that occurs between the photoconductor 11, the intermediate transfer belt 30, and the black toner image changes the charge of a part of the toner constituting the black toner image to 0 or reverse polarity (positive electrode). The photoreceptors (hereinafter referred to as other color photoreceptors) 10 of the three downstream toner image forming units 10C, 10M, and 10Y have a negative polarity, and with respect to these three negative other color photoreceptors 11, Since the intermediate transfer belt 30 has a positive polarity, and the black toner having a reverse polarity also has a positive polarity, the retransfer phenomenon in which the toner is electrostatically transferred to the three other color photoreceptor surfaces 10a is a black toner. However, the physical contact with the other color photoreceptor surface 11a in the primary transfer region is also slightly caused by the help. Note that the toner that causes retransfer is a very small amount of toner in the toner image, so that it is at a level that does not affect the final image formed on the paper P.

  The toner that has been transferred to the other color photoreceptor surface 11a due to retransfer is blocked by the leading edge portion 1511 of the cleaning blade 151 provided in each of the toner image forming units 10C, 10M, and 10Y. The surface 11a is polished by the residual toner that has been dammed, and foreign matter adhering to the other-color photoconductor surface 11a is removed from the photoconductor surface 11a. The toner that has been transferred to the other color photoreceptor surface 11a due to retransfer is also supplied between the idle surface 11a of the other color photoreceptor and the leading edge 1511 of the cleaning blade 151 as a lubricant. It functions, and it is possible to prevent the leading edge portion 1511 from being worn or chipped by the idle rotation of the photosensitive member.

  Further, in order to more stably supply the toner to the other color photoconductor 11 in the monochrome mode, the control unit 80 shown in FIG. 1 controls the primary transfer power source 21 (see FIG. 2), and the black toner image passes. In doing so, it is preferable to apply a bias having a polarity (negative polarity) opposite to the polarity of the primary transfer bias to the primary transfer roll 20 facing each of the other color photoreceptors 11.

  Next, the intermediate transfer belt 30 shown in FIG. 1 will be described in detail. The intermediate transfer belt 30 shown in FIG. 1 has elasticity made of a rubber material as described above. Specifically, the intermediate transfer belt 30 shown in FIG. 1 has a belt base material and a conductive protective layer covering the surface of the belt base material. The surface of the conductive protective layer becomes the surface (outer peripheral surface) of the intermediate transfer belt 30.

  Examples of the belt base material include ethylene-propylene-diene copolymer rubber (EPDM), natural rubber (NR), chloroprene rubber (CR), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), fluorine rubber ( FKM), silicone rubber, epichlorohydrin rubber (CHR, ECO), polysulfide rubber, urethane rubber, and materials made by blending two or more of these materials with conductive materials such as carbon and other metal particles. However, the present invention is not limited to this.

  Further, the material for the conductive protective layer is not particularly limited as long as it can achieve the purposes of reducing the frictional resistance, improving the cleaning property of the residual toner on the intermediate transfer belt by reducing the surface roughness, and bleed resistance to the photoreceptor. In general, it is constituted by applying a conductive material paint containing fine powders such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA). Examples of the resin used for the conductive paint include silicone resin, fluororesin, fluorosilicone resin, polyacetal resin, urethane emulsion paint, ethylene-vinyl acetate copolymer, alcohol-soluble nylon resin, epoxy resin, polyester resin, acrylic resin, etc. Is mentioned.

  Further, as described above, the conductive foreign matter existing on the intermediate transfer belt surface 30a is considerably removed from the surface 30a by rubbing with the residue stirred in the space S. However, the harder the intermediate transfer belt, the more likely the piercing to the photoreceptor 11 is. Therefore, the intermediate transfer belt 30 preferably has a Young's modulus of the surface 30a of 1.5 GPa or less, more preferably 1 GPa. Further, in the present embodiment, even if the surface of the intermediate transfer belt is quite soft, it is possible to prevent the tip edge portion 721 of the cleaning blade 72 shown in FIG. The surface of the intermediate transfer belt where the Young's modulus of 30a is less than 1 MPa is almost rubbery, and the viscosity becomes too high, increasing the coefficient of friction. For this reason, the stress applied to the leading edge portion 721 of the cleaning blade 72 in pressure contact with the intermediate transfer belt surface 30a also increases, which is not preferable. The Young's modulus of the intermediate transfer belt surface 30a is more preferably 2 MPa or more.

  Next, an example of a method for manufacturing the intermediate transfer belt 30 will be described. After adding various additives including a conductive material to the belt base material, it is extruded into a cylindrical shape, followed by primary vulcanization and further secondary vulcanization. The molding may be another molding method such as centrifugal molding. The vulcanization is preferably high-pressure steam vulcanization, but may be other vulcanization methods such as pressureless oven vulcanization and press vulcanization. Vulcanization conditions vary depending on the rubber component and the amount used, but it is usually preferable to carry out at 130 to 170 ° C. for 0.5 to 6 hours. The secondary vulcanization is preferably performed, for example, in a hot air oven at 130 to 200 ° C. for about 0.5 to 8 hours. The belt base material is cut to a predetermined length, the front and back surfaces are polished, and a conductive protective layer coating is applied. Examples of a method for applying the paint include a spray method, an electrostatic method, a dipping method, a roll coater method, and a curtain flow method.

  The intermediate transfer belt 30 is not limited to a drum-shaped intermediate transfer member.

  Next, the developer container 141 of the developing device 14 shown in FIG. 2 will be described in detail. As described above, the developer container 141 contains a developer, and the toner in the developer is obtained by attaching various external additive particles to the surface of the toner base particles. It is not limited by. Examples of the toner include particles obtained by a kneading and pulverizing method in which a binder resin, a colorant, a release agent, a transfer auxiliary agent, and the like are kneaded, pulverized, and classified as necessary. Method of changing shape with mechanical impact force or thermal energy, emulsion polymerization of binder resin polymerizable monomer, and formed dispersion, colorant, mold release agent, transfer aid, if necessary Emulsion polymerization aggregation method to obtain toner particles by mixing with a dispersion liquid such as a charge control agent and heat-fusing, polymerizable monomer and colorant, release agent, necessary to obtain a binder resin Depending on the suspension polymerization method in which a solution such as a charge control agent is suspended in an aqueous solvent for polymerization, a binder resin and a colorant, a release agent, a transfer aid, and a solution such as a charge control agent as necessary. What is obtained by the dissolution suspension method etc. which suspend and granulate in an aqueous solvent can be used. In addition, a toner produced by a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure can be used. From the viewpoint of particle size distribution control, a suspension polymerization method, an emulsion polymerization aggregation method and a dissolution suspension method which are produced with an aqueous solvent are preferable, and an emulsion polymerization aggregation method is particularly preferable.

The toner is composed of a binder resin, a colorant, a release agent, and the like. If necessary, silica or a charge control agent may be used. The volume average particle size of the toner is preferably in the range of 2 to 12 μm, and more preferably in the range of 3 to 9 μm. Also, the average spherical coefficient (ML ² / A) × (100π / 4) of the toner base particles: ML is the absolute maximum length of the toner base particles, and A is the projected area of the toner base particles. By using those in the range, more preferably from 100 to 130, it is possible to obtain images with high development, transferability, and high image quality.

  Binder resins used include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; Α-methylene aliphatic monocarboxylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Examples of vinyl polymers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone; Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene- Mention may be made of maleic anhydride copolymers, polyethylene, polypropylene and the like. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  In addition, toner colorants include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite green oxa. Rate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.

  Typical examples of the release agent include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.

  The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  Further, the lubricant added to the toner includes solid lubricants such as higher alcohols, graphite, molybdenum disulfide, talc, fatty acids, fatty acid metal salts, etc .; low molecular weight polyolefin particles such as polypropylene, polyethylene, polybutene; softening point by heating ; Aliphatic amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; plants such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc. Animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc .; and their modified products can be used. In whether to use, or it may be used in combination. In particular, it is preferable to use a fatty acid metal salt, specifically zinc stearate, which has a high friction reducing effect due to its cleavage property. The amount of zinc stearate added is preferably 0.01 to 2.0% by weight, more preferably 0.05 to 0.5% by weight. When the amount is less than 0.01%, a sufficient lubricating effect cannot be exhibited. When the amount is more than 2.0%, the amount of adhesion to the photoconductor 11 becomes excessive.

  In addition, for the purpose of removing adhered matter and deteriorated matter on the surface 11a of the photosensitive member 11, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, and the like can be added to the toner. Inorganic particles having excellent polishing properties are particularly preferred. Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used. Moreover, titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecyl benzene sulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2-amino) Ethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane Hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. Further, hydrophobic treatment with a higher fatty acid metal salt such as silicone oil, aluminum stearate, zinc stearate, calcium stearate can be preferably performed.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles. If the particle size is too small, the polishing ability is insufficient, and if it is too large, the surface 11a of the photoreceptor is likely to be damaged. Therefore, the average particle size is in the range of 5 to 1000 nm, preferably in the range of 5 to 800 nm. More preferably, the one in the range of 5 to 700 nm is used. Moreover, it is preferable that the sum with the addition amount of the said lubricant is 0.6 mass% or more.

  Other inorganic oxides added to the toner are small-diameter inorganic oxides having a primary particle size of 40 nm or less for powder flowability, charge control, etc. Mention may be made of large-diameter inorganic oxides. Known inorganic oxide particles can be used, but it is preferable to use silica and titanium oxide in combination for precise charge control. Further, the surface treatment of the small-diameter inorganic particles increases the dispersibility and increases the effect of improving the powder fluidity.

  The toner can be produced by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. In addition, when the toner base particles are produced by a wet method, external addition can also be performed by a wet method.

  Further, as the developer carrier accommodated in the developer accommodating body 141, iron powder, glass beads, ferrite powder, nickel powder, or those having a resin coating on the surface thereof are used. Further, the mixing ratio of the carrier and the toner can be set as appropriate.

  The developer container 141 shown in FIG. 2 contains a so-called two-component developer containing toner and carrier, but the developer container contains a one-component developer containing no carrier. There may be.

  Next, a photoreceptor that can be used for the photoreceptor shown in FIG. 1 will be described in detail.

  The photosensitive member that can be used here has a configuration in which a photosensitive layer is formed on the outer peripheral surface of a conductive substrate and, if necessary, a protective layer is formed on the photosensitive layer. The photosensitive layer may be a single layer type or a function separation type composed of a charge generation layer and a charge transport layer. The protective layer is a high-strength surface layer containing a resin having a structural unit having a charge transport function and having a crosslinked structure.

  The conductive base material may be a metal drum such as aluminum, copper, iron, stainless steel, zinc, nickel, or aluminum, copper, gold, silver, platinum, palladium, titanium, sheet, paper, plastic, or glass. Metals such as nickel-chrome, stainless steel, copper, and indium may be vapor-deposited, conductive metal compounds such as indium oxide and tin oxide may be vapor-deposited, metal foil may be laminated, or carbon black / oxidized. Indium, tin oxide, antimony oxide powder, metal powder, copper iodide, and the like may be dispersed in a binder resin and applied to conduct a conductive treatment. The shape of the conductive substrate is not limited to a drum shape, and may be a sheet shape or a plate shape. In addition, when the conductive base material is a metal pipe, the surface may be left as it is, and in advance processing such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. It may be done. An undercoat layer may be formed on the surface of the conductive substrate as desired.

  As the charge generation material used for the charge generation layer, any known charge generation material can be used. For infrared light, phthalocyanine pigments, squarylium, bisazo, trisazo, perylene, dithioketopyrrolopyrrole, and for visible light, condensed polycyclic pigments, bisazo, perylene, trigonal selenium, dye-sensitized metal oxide particles and the like are used. Among these, a particularly excellent performance is obtained, and a phthalocyanine pigment is used as a charge generating material that is preferably used. By using this, it is possible to obtain a photoreceptor having particularly high sensitivity and excellent repeatability. In addition, phthalocyanine pigments generally have several crystal types, and any of these crystal types can be used as long as it is a crystal type capable of obtaining a sensitivity suitable for the purpose. Particularly preferred charge generating materials include chlorogallium phthalocyanine, dichlorotin phthalocyanine, hydroxygallium phthalocyanine, metal-free phthalocyanine, oxytitanyl phthalocyanine, chloroindium phthalocyanine, and the like.

  Phthalocyanine pigment crystals are produced by a known method, and phthalocyanine pigments are mechanically dry-pulverized with an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, etc. It can be produced by wet pulverization using a mortar, sand mill, kneader or the like.

  As the charge transport material for the charge transport layer, any known material can be used, but the following can be exemplified. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3 Pyrazoline derivatives such as-(p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (P-methyl) phenylamine, N, N'-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluoren-2-amine, N, N′-diphenyl-N, Aromatic tertiary diamino compounds such as N′-bis (3-methylphenyl)-[1,1-biphenyl] -4,4′-diamine, 3- (4′dimethyla 1,2,4-triazine derivatives such as nophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenyl Hydrazone derivatives such as aminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2, Benzofuran derivatives such as 3-di (p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, enamine derivatives, N-ethylcarbazole, etc. Carbazole derivatives, poly-N-vinylcarba Hole transport materials such as sol and its derivatives. Quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- ( 4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5 -Oxadiazole compounds such as bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyldiphenoquinone, etc. Electron transport materials such as diphenoquinone compounds. Or the polymer etc. which have the group which consists of the said compound in a principal chain or a side chain are mention | raise | lifted. These charge transport materials can be used alone or in combination of two or more.

  Any known binder resin for the charge transport layer can be used, but an electric insulating film-forming resin is preferred. For example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-acetic acid Vinyl copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, Casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxymethyl cellulose, vinylidene chloride polymer wax, polyurethane Although the like, but is not limited to these. These binder resins are used singly or in combination of two or more. In particular, polycarbonate resins, polyester resins, methacrylic resins, and acrylic resins are compatible with charge transport materials, soluble in solvents, and strong. Excellent and preferably used. The mixing ratio (weight ratio) between the binder resin and the charge transport material can be arbitrarily set in any case, but attention must be paid to a decrease in electrical characteristics and a decrease in film strength. The thickness of the charge transport layer is 5 to 50 μm, preferably 10 to 40 μm.

Here, the image forming apparatus adopting the full color tandem system in which four toner image forming units are arranged has been described as an example. However, the image forming apparatus of the present invention is a rotary type in one toner image forming unit. The present invention can also be applied to an image forming apparatus that employs a method of forming a four-color toner image using a full-color developing device.
(Example)
EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following description, “part” means “part by mass” unless otherwise specified.
Example 1
A FUJI XEROX Docu Print C830, which has a rotary full-color developing device as a test machine, and transfers each color toner image sequentially so as to overlap each other on the intermediate transfer belt to form a full-color image. Was used.

  Here, a belt cleaner having the same configuration as that of the belt cleaner shown in FIG. 3 was incorporated. The lower seal is a polyurethane resin sheet having a thickness of 20 μm, and the blocking member is a PET resin sheet provided with an opening having a thickness of 50 μm. A wrap region (see arrow L in FIG. 3) is formed between the blocking member and the tip of the cleaning blade. The intermediate transfer belt was changed to an elastic intermediate transfer belt having a surface Young's modulus of 1.4 Gpa. The device size of Docu Print C830 made by FUJI XEROX before remodeling and the device size of the image forming apparatus after remodeling were the same.

  In the test, the Docu Center Color 400CP toner, which is a polymerized toner, is used, and 20,000 sheets each at high temperature and high humidity (28 ° C., 80% RH) and low temperature and low humidity (10 ° C., 20% RH) in full color, total 40,000. A running test of the sheets was performed. The modified tester was in an unused (new) state before the start of the test, and the test was started because the space defined by the lower seal and the blocking member (see S in FIG. 3) was empty. Before the toner band was formed, the toner band was transferred to the intermediate transfer belt, and the transferred toner band was allowed to reach the leading edge of the cleaning blade without being transferred onto the paper. Further, during the running test, the toner band was periodically formed so that the toner band reached the edge portion of the cleaning blade.

  The evaluation was carried out with respect to toner cleaning performance of the intermediate transfer belt, blade edge damage and blade chatter of the cleaning blade provided in the belt cleaner. For the evaluation of the cleaning property, two types of images, a low image density image with many white background portions and a high image density image with many images, were used as the collected images depending on the location in the longitudinal direction. Evaluation was performed. The results in each evaluation are shown in Table 1 together with the overall judgment results.

[Cleanability and blade edge damage at low image density]
The cleaning performance is confirmed by evaluating the cleaning performance of the cleaning blade installed in the belt cleaner under stress conditions, and measuring the blade edge damage with a laser microscope (manufactured by Keyence Corporation). Measurements were made. Judgment criteria are as follows.
◎: No cleaning performance problem, small edge wear amount ○: No cleaning performance problem, medium edge wear amount △: No cleaning performance problem, large edge wear amount ×: Defect in cleaning occurred XX: Blade meklet occurred and continued running Impossible [cleanability at high image density]
For confirmation of the cleaning property, the cleaning performance of the cleaning blade was evaluated under stress conditions. Judgment criteria are as follows.
○: No problem with cleaning performance △: Minor cleaning failure occurred ×: Cleaning failure occurred XX: Unable to continue running due to blade peeling [Blade chatter]
The blade chatter of the cleaning blade installed in the belt cleaner was judged by sensory evaluation of sound during running under high temperature and high humidity (28 ° C., 80% RH).
◎: No chatter sound can be heard at all. ○: Very chatter sound can be heard. △: Chatter sound can be heard slightly.

(Example 2)
Example 1 was performed using an image forming apparatus having the same configuration as that of the image forming apparatus used in Example 1 except that the intermediate transfer belt was replaced with an elastic intermediate transfer belt having a surface Young's modulus of 0.1 GPa. Tests similar to those performed in Example 1 were performed, and each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.

(Example 3)
Example 1 was performed using an image forming apparatus having the same configuration as that of Example 1 except that the intermediate transfer belt was replaced with an elastic intermediate transfer belt having a Young's modulus of 2 MPa on the surface. The same tests as those described above were performed, and each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.

Example 4
Using the image forming apparatus having the same configuration as that of the image forming apparatus used in Example 3, the test was performed in the same manner as in Example 1 except that the regular toner band was not formed during the running test. Each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.

(Example 5)
Using the image forming apparatus having the same configuration as that of the image forming apparatus used in Example 3, the test was performed in the same manner as in Example 1 except that the toner band was not formed before the start of the test. Each evaluation was performed in the same manner. The results in each evaluation are shown in Table 1 together with the overall judgment results.

(Example 6)
Example except that the blocking member extending to a position higher than the height position of the leading edge portion of the cleaning blade is replaced with a blocking member whose upper end coincides with the height position of the leading edge portion. Using the image forming apparatus having the same configuration as that of the image forming apparatus used in No. 3, a test was performed in the same manner as in Example 4 in which the regular toner band was not formed during the running test. Each evaluation was performed. The results in each evaluation are shown in Table 1 together with the overall judgment results. The belt cleaner of the image forming apparatus used in Example 6 does not have a wrap region (see arrow L in FIG. 3).

(Example 7)
An image forming apparatus having the same configuration as that of the image forming apparatus used in the third embodiment is used except that the blocking member provided with an opening connected to the inside of the housing is replaced with a blocking member having no opening. Then, the test was conducted in the same manner as in Example 5 in which the toner band was not formed before the start of the test, and each evaluation was conducted in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.

(Comparative Example 1)
An image forming apparatus having the same configuration as that of the image forming apparatus used in Example 1 was used except that both the lower seal and the blocking member were removed. That is, the belt cleaner of Docu Print C830 manufactured by FUJI XEROX before remodeling was used as it was.

The test was performed in the same manner as in Example 1 except that the toner band was not formed before the start of the test and the regular toner band was not formed during the running test, and each evaluation was performed in the same manner as in Example 1. . The results in each evaluation are shown in Table 1 together with the overall judgment results.
(Comparative Example 2)
Toner band formation using an image forming apparatus having the same configuration as that of the image forming apparatus used in Comparative Example 1, except that the intermediate transfer belt is replaced with an elastic intermediate transfer belt having a Young's modulus of 0.1 GPa on the surface. A test similar to the test performed in Comparative Example 1 was performed, and each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.
(Comparative Example 3)
In Comparative Example 1, an image forming apparatus having the same configuration as the image forming apparatus used in Comparative Example 1 was used except that the intermediate transfer belt was replaced with an elastic intermediate transfer belt having a Young's modulus of 2 MGPa on the surface. The same tests as those described above were performed, and each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.
(Comparative Example 4)
A test similar to the test performed in Comparative Example 1 was performed, except that an image forming apparatus having the same configuration as that of the image forming apparatus used in Comparative Example 3 was used to perform regular toner band formation during the running test. Each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.
(Comparative Example 5)
A test similar to the test performed in Comparative Example 1 was performed except that the toner band was formed before the start of the test using the image forming apparatus having the same configuration as that of the image forming apparatus used in Comparative Example 3. Each evaluation was performed in the same manner as in 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.
(Comparative Example 6)
Performed in Comparative Example 1 except that the image forming apparatus having the same configuration as the image forming apparatus used in Comparative Example 3 was used to form a toner band before the start of the test and a regular toner band formed during the running test. The same tests as those described above were performed, and each evaluation was performed in the same manner as in Example 1. The results in each evaluation are shown in Table 1 together with the overall judgment results.

  As shown in Table 1, in each comparative example in which both the lower seal and the blocking member were removed, the evaluation of cleaning performance and blade edge damage at low image density was poor. This deterioration of the cleaning property is due to the occurrence of abrasion or peeling on the edge portion of the blade. As the hardness of the surface of the intermediate transfer belt becomes softer, the tip edge portion of the cleaning blade is more likely to be worn or creased. At the low image density, wear and chipping occurred at the edge portion of the blade, and in Comparative Example 2 using the intermediate transfer belt with the surface hardness reduced to 0.1 GPa, blade peeling occurred at the low image density. It has fallen into poor running continuity. Further, in the comparative example 2, the cleaning performance is deteriorated even at a high image density where residual toner is easily supplied to the leading edge portion. Further, when comparing the results of Comparative Examples 3 to 6 using a soft intermediate transfer belt with a surface hardness of 2 MPa, as in Comparative Example 6, toner band formation before the start of the test is performed periodically during the running test. It can be seen that the cleaning performance is not improved at all even if the toner band is formed and the residual toner is positively supplied to the leading edge portion. In comparison with these comparative examples, good results were obtained in any of the examples in which both the lower seal and the blocking member were provided. In particular, as shown in the results of Examples 3 to 7, even when an intermediate transfer belt having a soft surface hardness of 2 MPa is used, the cleaning property is maintained well, and the occurrence of blade chattering is prevented. Further, when Example 3 and Examples 4 to 7 are compared, there is a difference in cleaning performance and blade chatter at a low image density. These differences are that in Example 5 and Example 7, particles that function as an abrasive are not supplied to the leading edge immediately after image formation, and the leading edge is slightly worn. This is considered to be a difference due to the fact that the number of particles decreased during the test and the tip edge portion was also slightly worn. From this, it can be seen that the toner band is formed before the use of the image forming apparatus and further periodically after the start of use, thereby further suppressing the wear of the leading edge portion.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a view showing in more detail the toner image forming unit of black toner arranged at the most upstream in the moving direction of the intermediate transfer belt among the four toner image forming units shown in FIG. FIG. 2 is a view of a part of the cleaning device shown in FIG. 1 as viewed from one end side of a central axis when the intermediate transfer belt is circulated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Toner image forming unit 11 Photoconductor 11a Surface 110 Rotating shaft 12 Charger 13 Exposure device 14 Developing device 15 Cleaning device 16 Electric discharger 20 Primary transfer roll 30 Intermediate transfer belt 30a Surface 40 Batch transfer device 50 Fixing device 60 Paper Tray 70 Belt Cleaner 71 Housing 72 Cleaning Blade 721 Tip Edge 73 Lower Seal 74 Blocking Member 80 Control Unit S Space

Claims (1)

In an image forming apparatus for forming a toner image on a surface of an image carrier and transferring and fixing the toner image on a recording medium to form an image composed of a fixed toner image on the recording medium.
An intermediate transfer body that circulates and moves in a predetermined direction, transfers a toner image from the image carrier to the surface, and transfers the transferred toner image to a recording medium;
A cleaning blade having elasticity that the edge of the tip is pressed against the surface of the intermediate transfer body after the toner image is transferred to the recording medium, and scrapes remaining on the surface are scraped off from the surface;
Residue that receives the residue scraped off from the surface of the intermediate transfer member by the cleaning blade and spreads from the edge of the tip to the upstream side in the moving direction of the intermediate transfer member to define a predetermined space for retaining the scraped residue. An image forming apparatus comprising: a member.

Images