JP2008020819A - Image forming apparatus and process unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus where protective agents for preventing deterioration caused by proximity discharge are fed to the surface of an image carrier, by which the uniform feed of the protective agents to the axial direction of the image carrier is performed, thus the prevention of deterioration in the surface of the image carrier caused by proximity discharge and the suppression of the increase in the escaping amount of toner occurring by the adverse influence of deterioration in the projective agents caused by the proximity discharge on a cleaning blade are made consistent. <P>SOLUTION: In the image forming apparatus comprising: a charger for charging the surface of a photoreceptor by proximity discharge from a charging roller 111 arranged proximately to a photoreceptor 1; a developing device 120 for developing a latent image on the photoreceptor; and a cleaning device having a cleaning blade 2 for removing toner remaining on the photoreceptor 1 after the transfer of a toner image after the development to a transferring material, the apparatus is provided with: a first protective agent feeding means 151 and a second protective agent feeding means 161 for applying protective agents for protecting the surface of the photoreceptor to a plurality of parts in the surface moving direction of the photoreceptor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a fax machine, and a printer, and a process unit employed in the image forming apparatus.

  Conventionally, in an electrophotographic image forming apparatus, as the photosensitive member rotates, its peripheral surface is uniformly charged by a charging device, and then writing is performed by an exposure device to form an electrostatic latent image on the photosensitive member. The developing device attaches toner to the electrostatic latent image to make the electrostatic latent image visible, and forms a toner image on the photoreceptor. Then, the toner image on the photosensitive member is transferred to the recording medium by the transfer device, and then the transferred image is fixed by the fixing device to record the image on the recording medium. On the other hand, the remaining toner on the peripheral surface of the photoreceptor after the toner image transfer is cleaned by a cleaning device to prepare for image formation again. In the image forming apparatus, such an image forming process is repeatedly performed.

  In general, a cleaning device employed in an image forming apparatus uses a cleaning blade made of an elastic material such as polyurethane rubber as a cleaning member because of its simple configuration and excellent cleaning performance. Widely known. The cleaning blade is cleaned by supporting the base end with a support member, pressing the tip ridge line portion against the peripheral surface of the photoreceptor, and clogging and removing the toner remaining on the image carrier.

  Supply means for supplying zinc stearate or the like as a lubricant to the surface of the photoconductor as a lubricant for the purpose of reducing the frictional force between the cleaning blade and the photoconductor or reducing the toner adhesion force. It has been known. As a means for supplying zinc stearate, a rotatable fur brush and a solid zinc stearate bar are provided, the zinc stearate bar is pressed against the fur brush, and the zinc stearate is pressed with the fur brush. The bar is scraped off and applied onto the image carrier.

  In addition, for the purpose of preventing chemical deterioration of the photoconductor, there are some which supply zinc stearate or the like as a protective agent to the surface of the photoconductor. For example, when a proximity discharge is performed using a charging member disposed in the vicinity as a charging device for applying a charge on the image carrier, there is a problem that the photoconductor is oxidized by the discharge and the chemical deterioration is likely to proceed. In particular, in a method in which a bias in which an AC voltage is superimposed on a DC voltage is applied to the charging member, a high energy discharge is generated as compared with the DC voltage, and thus the influence of chemical deterioration of the photosensitive member is large. In order to solve the problem due to the proximity discharge, there is known one that supplies a protective agent on the photoconductor so that the surface of the photoconductor is not directly exposed to the discharge (for example, Patent Document 1).

  Thus, when zinc stearate is supplied as a protective agent from electric discharge, it is desired to form a uniform protective layer by uniformly applying the protective agent to the surface of the photoreceptor for that purpose. The means for supplying zinc stearate is the same as the means for supplying zinc stearate as a lubricant on the photoreceptor, and a rotatable fur brush, a solid bar of zinc stearate, And a bar of zinc stearate is pressed against a fur brush, the bar of zinc stearate is scraped off with a fur brush, and this is applied onto an image carrier. However, when zinc stearate as a protective agent is supplied upstream of the cleaning blade as in the case of supplying zinc stearate as the lubricant, the zinc stearate reaches the cleaning blade together with the transfer residual toner, and a part thereof. Are removed by the cleaning blade together with the residual toner. For this reason, after passing through the cleaning blade, the zinc stearate on the surface of the photoreceptor is unevenly present. When the photoconductor in such a state passes through the charging device, the region where zinc stearate does not exist is directly exposed to discharge and deterioration proceeds. Further, since the input amount and input pattern of the transfer residual toner differ depending on the output image pattern, it is also unstable to remove the zinc stearate by the cleaning blade. Therefore, the presence of zinc stearate on the photoconductor after passing through the cleaning blade is very unstable and non-uniform, and in the case of supplying zinc stearate upstream of the cleaning blade, This is not a uniform state desired as a protective agent for protecting the surface of the photoreceptor.

  Therefore, in Japanese Patent Application Laid-Open No. 2004-228620, the applicant of the present invention protects between the charging device and the image forming process means closest to the charging device out of the image forming process means that contacts the surface of the photoconductor on the upstream side of the charging device in the direction of movement of the photoconductor surface. It has been proposed to provide an agent supply means. In the apparatus of Patent Document 2, in the above-described image forming process, after passing through the cleaning blade, zinc stearate is applied immediately before the photoreceptor is discharged by the charging device, so that it is not affected by residual toner. The protective agent layer is uniformly formed on the surface of the photoreceptor, and the deterioration of the photoreceptor due to proximity discharge is effectively suppressed.

JP 2004-341480 A Japanese Patent Laying-Open No. 2005-115311

  As in Patent Document 1 and Patent Document 2, when the protective agent is supplied to the photosensitive member at one location, the supply amount of the protective agent may be uneven in the longitudinal direction of the photosensitive member over time. In particular, it tends to occur when the solid protective agent formed in a bar shape is applied to the photoreceptor while being scraped off by a fur brush as the supply means.

  As one of the causes, there is a slight bias of contact at the time of assembling the initial fur brush and the bar-shaped solid protective agent. For example, when the contact state between the fur brush and the bar-shaped solid protective agent is uneven and uneven in the longitudinal direction, one end of the bar-shaped solid protective agent strongly contacts the brush member and the other end is It will contact weakly. In such a case, while the number of output images is small and the amount of shaving of the bar-shaped solid agent is small, the influence of the contact strength between the brush member and the bar-shaped solid protective agent is small, and the protection on the photoconductor There is a slight amount of bias in the supply amount of the agent. However, as the cumulative number of image outputs increases, the effect is accumulated, and uneven wear of the bar-shaped solid protective agent occurs in which the amount of scraping at one end of the solid protective agent is large and the amount of scraping at the other end is small. If this happens, the supply amount of the protective agent on the photoreceptor is extremely biased.

  Another cause is the difference in the image input pattern in the axial direction of the photoreceptor over time. If there is a difference in the image input pattern, the surface condition of the photoconductor changes, the amount of protective agent supplied from the fur brush to the photoconductor varies in the longitudinal direction, and the amount of shaving of the bar-shaped solid protective agent becomes uneven It is to become.

  In addition, among the ones where the protective agent is supplied to the photosensitive member, in the apparatus of Patent Document 2, the toner remaining after transfer is not sufficiently blocked by the cleaning blade, and toner slip increases. In the apparatus of Patent Document 2, when the zinc stearate uniformly applied on the surface of the photoreceptor passes through the discharge region of the charging device, it is oxidized and deteriorates as a substitute for the photoreceptor. Deteriorated zinc stearate loses lubricity, but rather increases tackiness. This deteriorated zinc stearate is deposited on the surface of the photoreceptor during repeated image formation. For this reason, when deteriorated zinc stearate is interposed between the photosensitive member and the cleaning blade, the contact state between the cleaning blade and the photosensitive member becomes non-uniform, and in the nip portion where the cleaning blade and the photosensitive member contact each other, As a result of partial pressure shortage, it is considered that the amount of slipping toner increases. A part of the slipping toner adheres to the charging roller, and the charging roller becomes dirty due to repeated image forming operations, which causes a problem in that the high durability is hindered. Therefore, a countermeasure such as separately providing a charging roller cleaner can be considered, but this leads to an increase in cost.

  As described above, in the case where zinc stearate or the like is supplied as a protective agent on the photoconductor, the proximity of the photoconductor is provided regardless of whether the supply location is upstream of the cleaning device or downstream of the cleaning device and upstream of the charging device. It is difficult to achieve both suppression of deterioration due to discharge and suppression of increase in the amount of toner passing through.

The present invention has been made in view of the above background, and the first object thereof is to employ a charging method based on proximity discharge, and to provide a protective agent for preventing deterioration due to proximity discharge on the surface of the image carrier. To provide an image forming apparatus capable of supplying a uniform protective agent in the axial direction of the image carrier in order to prevent deterioration of the surface of the image carrier due to proximity discharge in the supplied image forming apparatus. It is.
In addition to the first purpose, the second purpose is to prevent the surface of the image carrier from being deteriorated due to the proximity discharge, and the protective agent supplied to the surface of the image carrier is deteriorated by the proximity discharge. It is another object of the present invention to provide an image forming apparatus and a process unit capable of suppressing an increase in the amount of toner passing through which adversely affects a cleaning blade.

In order to achieve the first object, the invention according to claim 1 is directed to an image carrier that carries an electrostatic latent image and a proximity discharge from a charging member that is arranged in proximity to the image carrier. A charging device that charges the surface; a developing device that develops a latent image on the image carrier; and a cleaning blade that removes toner remaining on the image carrier after the developed toner image is transferred to a transfer material. A plurality of protective agent supplying means for applying a protective agent for protecting the surface of the image carrier at a plurality of locations in the surface movement direction of the image carrier. It is a feature.
In order to achieve the second object, the invention of claim 2 is characterized in that the image is carried out by proximity discharge from an image carrier carrying an electrostatic latent image and a charging member arranged in proximity to the image carrier. A charging device for charging the surface of the carrier, a developing device for developing the latent image on the image carrier, and a cleaning for removing the toner remaining on the image carrier after the developed toner image is transferred to a transfer material. In the image forming apparatus including a cleaning device having a blade, a first supplying agent is supplied to the first supply region downstream of the cleaning blade and upstream of the charging device with respect to the surface movement direction of the image carrier. It is characterized by comprising protective agent supply means and second protective agent supply means for supplying the protective agent to a second supply region downstream of the charging device and upstream of the cleaning blade.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, a rotatable supply member disposed as contacting the first supply region of the image carrier as the first protective agent supply means, A solid protective agent in contact with the supply member, a rotatable supply member disposed as a second protective agent supply means in contact with the second supply region of the image carrier, and a solid protection in contact with the supply member Each of which is supplied to the first supply region and the second supply region by applying the protective agent scraped off by the supply member onto the image carrier. It is characterized by being.
According to a fourth aspect of the present invention, in the image forming apparatus of the second aspect, the second protective agent is provided with an intermediate transfer member that contacts the image carrier and transfers a toner image formed on the image carrier. The supply means includes a rotatable supply member that contacts the surface of the intermediate transfer member, and a solid protective agent that contacts the supply member, and the protective agent scraped off by the supply member is applied to the intermediate transfer member, The protective agent is supplied to the second supply region of the image carrier through an intermediate transfer member.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect of the present invention, a rotatable supply member arranged so that the first protective agent supply means contacts a first supply region on the surface of the image carrier; A solid protective agent that contacts the supply member, and supplies the protective agent scraped off by the supply member to the first supply region of the image carrier.
According to a sixth aspect of the present invention, in the image forming apparatus according to the second aspect, the second protective agent supplying means develops the latent image on the image carrier using a toner containing a protective agent. The protective agent is supplied to the second supply region of the image carrier.
According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect of the present invention, a rotatable supply member disposed so that the first protective agent supply means contacts a first supply area on the surface of the image carrier, A solid protective agent that contacts the supply member, and supplies the protective agent scraped off by the supply member to the first supply region of the image carrier.
The invention according to claim 8 is the image forming apparatus according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the angle of the tip ridge line portion of the cleaning blade is 95 ° or more and 140 ° or less. It is characterized by.
The invention of claim 9 is the image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the toner has an average circularity of 0.98 or more. It is what.
The invention according to claim 10 is the image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the image carrier is made of fine particles made of an inorganic compound. What has the surface protection layer which consists of is used.
The invention according to claim 11 is the image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the image carrier comprises a binder resin having a crosslinked structure. It is characterized by using a material having a surface protective layer.
According to a twelfth aspect of the present invention, in the image forming apparatus of the eleventh aspect, a charge transport layer is provided in the structure of the surface protective layer.
According to a thirteenth aspect of the present invention, an image carrier, a charging device, a cleaning device, and a protective agent supplying means for supplying a protective agent to the surface of the image carrier to protect the surface of the image carrier are integrated. In the process unit that is formed in a manner and is detachable from the main body of the image forming apparatus, the protective agent supplying means is as defined in claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or A first protective agent supply unit and a second protective agent supply unit described in the image forming apparatus are employed.

In the first aspect of the present invention, even if the supply amount of the protective agent on the image carrier is biased in the axial direction in one of the plurality of protective agent supply means, it is supplied by other protective agent supply means. A large amount of the protective agent is supplied to a portion where the protective agent on the image carrier is small, and a small amount is supplied to a large portion. As a result, the amount of the protective agent present on the image carrier after passing through the plurality of protective agent supply means is made more uniform than the bias after passing through one protective agent supply means. This is thought to be due to the property that when a protective agent having lubricity is supplied in layers on top of a protective agent having lubricity, such as zinc stearate, it does not accumulate more than a certain level. That is, when supplying the protective agent to the image carrier, the amount of the protective agent supplied in an overlapping manner varies depending on the amount of the protective agent on the surface of the image carrier. Thus, the supply amount can be kept small in the axial direction.
According to the invention of claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, the protective agent supplying means is provided at a plurality of specific locations, and the deterioration due to proximity discharge is suppressed, In addition, the increase in the amount of toner passing through the cleaning blade due to the deteriorated protective agent is suppressed. Specifically, by supplying the protective agent to the first supply region by the first protective agent supply means, the protective agent is not partially removed from the image carrier before reaching the discharge region of the charging device, The discharge region is passed with the uniform protective layer formed. Therefore, it is possible to effectively prevent the deterioration of the surface of the image carrier due to the proximity discharge. In addition, the second protective agent supply means supplies a protective agent that has not been deteriorated newly on the protective agent that has deteriorated when passing through the discharge region in the second supply region, and the protective agent that has deteriorated passes through the cleaning blade. Avoid direct contact with the cleaning blade. According to the experiments described below, the present inventors contacted the deteriorated protective agent directly with the cleaning blade by supplying a new protective agent on the image carrier even when the deteriorated protective agent is deposited on the image carrier. It has been found that, by making it difficult to suppress, the adverse effect of the deteriorated protective agent on the cleaning blade can be suppressed, and the increase in toner slipping from the cleaning blade can be suppressed. In this way, by supplying the protective agent to the first supply area by the first protective agent supply means and supplying the protective agent to the second supply area by the second protective agent supply means, the conventional image carrier of the protective agent can be supplied. It is possible to achieve both suppression of deterioration due to proximity discharge and suppression of an increase in the amount of toner passing through the cleaning blade due to the deteriorated protective agent, which has been difficult with a single operation.

According to the first aspect of the present invention, in an image forming apparatus that employs a charging method by proximity discharge and supplies a protective agent for preventing deterioration due to proximity discharge to the surface of the image carrier, an image carrier caused by proximity discharge In order to prevent the deterioration of the surface, there is an excellent effect that a uniform protective agent can be supplied in the axial direction of the image carrier.
According to the invention of claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, in addition to the effect of claim 1, an image carrier caused by proximity discharge In addition to preventing the surface from being deteriorated, the protective agent supplied to the surface of the image carrier can be prevented from being deteriorated by the proximity discharge and adversely affecting the cleaning blade, thereby suppressing an increase in the amount of toner passing through.

  Hereinafter, an embodiment in which the present invention is applied to a printer which is an image forming apparatus will be described. First, the configuration and operation of the printer according to this embodiment will be described. FIG. 1 is a schematic configuration diagram of an entire printer 200 according to the present embodiment. The printer 200 includes a process unit 100, an optical writing unit 101, a paper feed cassette 10, a plurality of conveyance roller pairs 20, a recording material conveyance path 30, a registration roller pair 31, a transfer conveyance unit 40, a fixing device 50, and a discharge roller pair. 60 and so on.

  The optical writing unit 101 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates laser light onto a surface of a photoconductor described later based on image data by a known technique.

  FIG. 2 is a schematic configuration diagram showing a schematic configuration of the process unit 100 employed in the printer 200 according to the present embodiment. In the figure, a process unit 100 that generates a toner image includes a drum-shaped photoreceptor 1, a charging device 110, a developing device 120, a photoreceptor cleaning device 130, a static eliminator 140, and the like.

  The charging device 110 serving as a charging means opposes a charging roller 111 as a rotating charging member that is driven to rotate while a charging bias is applied to the photoreceptor 1 serving as a latent image carrier through a predetermined minute gap. ing. Then, with this minute gap, a discharge is generated from the charging roller 111 toward the photoconductor 1 to uniformly charge the photoconductor 1. The reason why the charging roller 111 is rotated is that the roller surface immediately after the discharge is retracted from the minute gap, and the roller surface that is not discharged is caused to enter the minute gap, thereby generating a stable discharge.

  As a charging means, conventionally, a corona charging method utilizing corona discharge has been generally adopted. In the corona charging method, a charge wire is disposed close to a member to be charged, and a high voltage is applied to the charge wire to cause a corona discharge between the charge wire and the member to be charged. Is charged. However, in the case of the corona charging method, discharge products such as ozone and nitrogen oxide (NOx) are generated with corona discharge. Since the discharge-generating substance may form a film of nitric acid or nitrate that adversely affects image formation on the surface of the photoreceptor, it is desirable to avoid the occurrence of the substance if possible. Therefore, in recent years, in place of the corona charging method, the development of a contact charging method or a proximity charging method in which the generation of a discharge generation material is small and charging can be performed with low power has been actively performed. In these methods, a charging member such as a roller, a brush, or a blade is brought into contact with or in close proximity to a charged member such as a photosensitive member, and a voltage is applied to the charging member to charge the surface of the charged member. It is. According to this method, compared to the corona charging method, the generation of a discharge generation material is small, and low power can be realized, so that the utility is high. In addition, since a large charging device is not required, the device can be miniaturized, which meets the needs for miniaturization of the device. Furthermore, when a spherical toner formed by a polymerization method is used, a cleaning failure is more likely to occur than a pulverized toner. However, the non-contact roller charging method has an advantage that the cleaning residual toner does not adhere to the charging device, and an abnormal image does not occur due to the adhesion.

   Therefore, the printer 200 employs a non-contact roller charging method. As a charging method, there is a method of charging a member to be charged by AC applied discharge by a charging member such as a roller brought into contact with the member to be charged. When this method is applied, it is preferable to use an elastic member that improves the contact between the surface of the member to be charged and the charging member and does not apply mechanical stress to the member to be charged. However, when an elastic member is used, the charging nip width is widened, which may cause the protective agent to easily adhere to the charging roller side. Therefore, it is more advantageous to charge the object to be charged without contact. Therefore, in the printer 200, the photosensitive member 1 is uniformly charged by a non-contact charging method.

  FIG. 3 is an enlarged configuration diagram showing the charging device 110 together with the photoreceptor 1. The charging device 110 includes a charging roller 111 as a charging member, a spacer 112, a spring 115, and a power source 116. The charging roller 111 includes a shaft portion 111a and a roller portion 111b as a charging portion. Among these, the roller portion 111b has a function of charging the surface of the photosensitive member so as to face the photosensitive member 1, and is configured to be rotatable by the rotation of the shaft portion 111a. The charging roller is provided with a spacer 112 serving as a gap holding member so that the roller portion 111b is disposed to face the photosensitive belt surface with a small gap. With the spacer 112, a portion of the surface of the photoconductor 1 that faces the image forming area 101 a where an image is formed is disposed so as not to contact the photoconductor 1. The length of the roller 111b in the longitudinal direction is set to be longer than the image forming area of the photoreceptor 1, and a minute gap G is formed by bringing the spacer 112 into contact with the non-image forming area 101b of the photoreceptor 1. is doing. The charging roller 111 rotates along with the surface of the photosensitive member 1 via the spacer 112. The minute gap G is configured such that the closest portion between the roller portion 111b and the photosensitive member 1 is 1 to 100 [μm]. The closest distance is more preferably 30 to 65 [μm]. In the printer 200, it is arranged to be 50 [μm].

  A spring 115 for pressing the charging roller 111 toward the member to be charged is attached to the shaft portion 111a. As a result, the minute gap G can be maintained with high accuracy. A power source 116 is connected to the shaft portion 111a, and the surface of the photoconductor 1 is uniformly charged by AC applied discharge in a minute gap between the surface of the photoconductor 1 and the surface of the roller portion 111b. In the printer 200, an alternating voltage in which an AC voltage that is an AC component is superimposed on a DC voltage that is a DC component is applied to the shaft portion 111a. By using the alternating voltage, the influence of variations in charging potential caused by minute gap fluctuations is suppressed, and uniform charging becomes possible.

  The roller portion 111b includes a cored bar as a conductive support having a cylindrical shape and a resistance adjusting layer formed on the outer peripheral surface of the cored bar, and has a diameter of 10 [mm].

  For example, a known material such as a rubber member can be used for the surface of the roller portion 111b, but it is more preferable to use a resin material. This is because, when a rubber member is used, it is difficult to maintain a minute gap with respect to the photoreceptor 1 due to water absorption or deflection of the rubber. Depending on the image forming conditions, only the central portion of the roller portion 111b may suddenly come into contact with the surface of the photoreceptor. It is difficult to deal with such disturbance of the surface layer of the photosensitive member due to the local and sudden contact of the roller portion 111b with the photosensitive member 1. Therefore, when the photoreceptor 1 is charged by the non-contact charging method, it is more preferable to use a hard material that can maintain a minute gap between the roller portion 111b and the photoreceptor 1 uniformly.

  As a hard material used for the roller part 111b surface, the following can be used, for example. That is, the resistance adjustment layer is formed of a thermoplastic resin composition (polyethylene, polypropylene, polymethyl methacrylate, polystyrene, or a copolymer thereof, etc.) in which a polymer type ion conductive agent is dispersed, and the surface of the resistance adjustment layer is cured. And a cured film treated with an agent. The cured film treatment can be performed, for example, by immersing the resistance adjusting layer in a treatment solution containing an isocyanate-containing compound. Alternatively, a cured film layer may be formed again on the surface of the resistance adjustment layer.

  In FIG. 1 described above, the surface of the photoreceptor 1 subjected to the charging process is irradiated with the laser light L modulated and deflected by the optical writing unit 101. Then, the potential of the irradiation part (exposure part) is attenuated. Due to this attenuation, an electrostatic latent image is formed on the surface of the photoreceptor 1. The formed electrostatic latent image is developed by a developing device 120 as developing means to become a toner image.

  The photosensitive member 1 as a latent image carrier is, for example, a drum-shaped tube in which a tube made of aluminum or the like is coated with a photosensitive layer made of an organic photosensitive material exhibiting photosensitivity, and further a charge transport layer is coated thereon. Is. Instead of the drum shape, a belt shape may be adopted.

  The developing device 120 includes a developing unit 122, a developer supply unit 119, and a developer stirring unit 123 in a developing casing 121. The developing unit 122 is provided with a developing sleeve 124 as a developer carrying member that exposes a part of the peripheral surface from the opening of the developing casing 121, a doctor blade 125, and the like.

  The cylindrical developing sleeve 124 is made of a non-magnetic material, and its surface is roughened by sandblasting or the like. By this roughening, the developer conveying ability is enhanced. Instead of roughening, fine grooves may be provided on the surface. The developing sleeve 124 is rotated by driving means (not shown). Inside the developing sleeve 124 that is driven to rotate in this way, the magnet roller 126 is fixed so as not to rotate around the sleeve. The magnet roller 126 has a plurality of magnetic poles divided in the circumferential direction. Under the influence of these magnetic poles, a magnetic field is formed on the periphery of the developing sleeve 124.

  The developer supply unit 119 and the developer stirring unit 123 of the developing device 120 contain a developer (not shown) including a magnetic carrier and a negatively chargeable toner. The developer supply unit 119 is provided with a supply conveyance screw 118, a T sensor 128 that is a toner concentration sensor, and the like. Further, the developer agitating unit 123 is provided with an agitating and conveying screw 127, a toner replenishing unit (not shown), and the like. The developer is agitated and conveyed in the depth direction in the figure by the supply and conveyance screw 118 and is frictionally charged. During the agitation and conveyance, the developer sleeve 124 comes into contact with the surface. Then, it is carried on the surface of the developing sleeve 124 due to the influence of a magnetic field extending from the surface of the developing sleeve 124 into the developer supplying unit 119, and is pumped up from the developer supplying unit 119 as the surface of the developing sleeve 124 rotates. . And it is conveyed to the position facing the doctor blade 125 with the rotation of the sleeve surface. At this facing position, the developer is regulated in layer thickness when it passes through the doctor gap that is the gap between the developing sleeve 124 and the doctor blade 125, and the frictional charging of the toner is promoted.

  The developer that has passed through the doctor gap reaches the developing area facing the photoreceptor 1 as the surface of the developing sleeve 124 rotates. In this development region, the photosensitive member 1 and the development sleeve 124 face each other with a predetermined development gap. On the sleeve surface in the developing region, magnetic carriers in the developer are raised by a magnetic force from a developing magnetic pole (not shown) of the magnet roller 126 to form a magnetic brush. The formed magnetic brush moves while the tip of the magnetic brush is rubbed against the photoconductor 1 to attach toner to the electrostatic latent image on the photoconductor 1. By this adhesion, a toner image is formed on the photoreceptor 1.

  The developer that has consumed the toner by the development returns into the developing device 120 as the developing sleeve 124 rotates. Then, it is separated from the sleeve surface under the influence of the repulsive magnetic field and gravity formed in the container, and returned to the developer supply unit 119 disposed at a position lower than the developing unit 122.

  A partition wall 129 is provided between the developer supply unit 119 provided with the supply conveyance screw 118 and the developer agitation unit 123 provided with the agitation conveyance screw 127. The partition wall 129 partitions the developer supply unit 119 and the developer stirring unit 123. In the developer supply unit 119, the supply / conveying screw 118 is driven to rotate by driving means (not shown), and the developer is supplied to the developing sleeve 124 while being conveyed from the front side to the back side in the drawing. The developer transported to the far end in the figure passes through an opening (not shown) provided in the partition wall 129 and is delivered to the developer stirring section 123 provided with a stirring transport screw 127. Then, after the agitating and conveying screw 127 is driven to rotate, it is conveyed from the back side to the near side in the figure, and then supplied through the other opening (not shown) provided in the partition wall 129. Return to the developer supply unit 119 side. In this way, the developer is circulated and conveyed in the developing device 120.

  The T sensor 128 is composed of a magnetic permeability sensor, is provided on the supply conveyance screw 118, and outputs a voltage having a value corresponding to the magnetic permeability of the developer conveyed thereon. Since the magnetic permeability of the developer shows a certain degree of correlation with the toner concentration, the T sensor 128 outputs a voltage having a value corresponding to the toner concentration. This output voltage value is sent to a control unit (not shown). The control unit includes a RAM and the like, and Vtref that is a target value of the output voltage from the T sensor 128 is stored therein. This Vtref is used for drive control of a toner supply device (not shown). Specifically, the control unit described above drives and controls a toner supply device (not shown) so that the value of the output voltage from the T sensor 128 approaches Vtref, and the developer of the developing device 120 from the toner supply unit (not shown). Toner is replenished into the stirring unit 123. By this replenishment, the toner concentration of the developer in the developing device 120 is maintained within a predetermined range.

  The toner image formed on the photoreceptor 1 is transferred onto the transfer paper P that is conveyed while being held on the surface of a conveyance belt 41 described later. The surface of the photoreceptor 1 that has undergone the transfer process is cleaned of residual toner by the photoreceptor cleaning device 130. The photoconductor cleaning device 130 includes a photoconductor removal casing 131, a holder 132 as a support member, a cleaning blade 2 as an elastic cleaning blade, a collection screw 134, and the like. The holder 132 is made of a rigid material such as metal or hard plastic. One end of the holder 132 is cantilevered by the photosensitive member removal casing 131, while the cleaning blade 2 is supported on the free end side.

  The cleaning blade 2 fixed to the free end side of the holder 132 is made of polyurethane rubber as a soft material, and scrapes off the transfer residual toner on the photoconductor 1 while the edge thereof is in contact with the surface of the photoconductor 1. The toner scraped off falls on the collection screw 134. The collection screw 134 that is rotationally driven by a driving means (not shown) is applied with a positive cleaning bias from a power supply (not shown). The transfer residual toner that has fallen on the collection screw 134 is conveyed toward a waste toner container (not shown) as the collection screw 134 rotates while electrostatically attracting to the collection screw 134. The photosensitive member 1 cleaned by the photosensitive member cleaning device 130 is neutralized by the neutralizer 140. Then, it is uniformly charged by the charging device 110 and returns to the initial state.

  In FIG. 1 described above, at the lower part of the printer 200 main body, a paper feed cassette 10 that accommodates a plurality of transfer sheets P in a bundle of sheets is detachably supported with respect to the printer 200 main body. The paper feed cassette 10 rotates the paper feed roller 11 that is in contact with the uppermost transfer paper P of the paper bundle accommodated therein, so that the transfer paper P is directed toward the recording material conveyance path 30. And send it out. The recording material transport path 30 includes a plurality of transport roller pairs 20 disposed at predetermined intervals in the transport path, and a registration roller pair 31 disposed near the end of the transport path. Then, the transfer paper P received from the paper feed cassette 10 is transported toward the registration roller pair 31 by the plurality of transport roller pairs 20. The registration roller pair 31 feeds the transfer paper P sandwiched between the rollers toward the transfer nip at a timing at which the transfer paper P can be brought into close contact with the toner image at a transfer nip described later. As a result, the transfer paper P is in close contact with the toner image on the photoreceptor 1 while being held on the surface of the transport belt 41 at the transfer nip.

  The transfer conveyance unit 40 includes a conveyance belt 41, a conveyance belt drive roller 42, a recording medium transfer bias roller 43, a conveyance belt cleaning device 44, and the like. The conveyor belt 41 has a base layer, an elastic layer, and a surface layer (not shown) from the inside of the belt loop. The base layer is a layer in which, for example, a fluorine-based resin having a small elongation or a rubber material having a large elongation contains a material that hardly stretches, such as canvas. As such a base layer, a material obtained by seamlessly molding a resin material such as polyvinylidene fluoride, polyimide, polycarbonate, or polyethylene terephthalate can be used. These materials can be used as they are, or the conductivity can be adjusted by a conductive material such as carbon black. The surface layer is a layer made of a material having a low surface energy and exhibiting good releasability from the toner, such as a fluorine-based resin, and is laminated on the base layer by a method such as spraying or dipping. The elastic layer is a layer made of an elastic material such as fluorine-based rubber or acrylonitrile-butadiene copolymer rubber, and is provided to exert a certain degree of elasticity on the entire belt.

  The conveyor belt 41 is stretched around a conveyor belt drive roller 42 and a recording medium transfer bias roller 43. Then, it is moved endlessly counterclockwise in the figure by the rotation of the conveying belt drive roller 42 driven by a belt drive motor (not shown). The recording medium transfer bias roller 43 is disposed so as to be in contact with the base layer side (inner peripheral surface side) of the transport belt 41 and receives a transfer bias from a power source (not shown). Further, the transfer belt 41 is pressed from the base layer side toward the photoconductor 1 to form a transfer nip where the transfer belt 41 that moves endlessly counterclockwise and the photoconductor 1 that rotates clockwise in the drawing abuts. Form. In the transfer nip, a transfer electric field is formed between the photosensitive member 1 and the recording member transfer bias roller 43 due to the influence of the transfer bias.

  The conveyance belt 41 holds the transfer paper P, onto which the transfer paper P is fed from the registration roller pair 31, on the upper stretched surface thereof. Then, the transfer paper P is caused to enter the transfer nip with the endless movement thereof. The toner image on the photoconductor 1 is transferred to the transfer paper P brought into close contact with the photoconductor 1 at the transfer nip due to the above-described transfer electric field and nip pressure.

  The transfer paper P onto which the toner image has been transferred in this way exits the transfer nip as the conveying belt 41 moves endlessly, and is then transferred to the fixing device 50. A small amount of toner adheres to the surface of the transport belt 41 after the transfer paper P is delivered. The toner is cleaned by a conveyor belt cleaning device 44 that sandwiches the conveyor belt 41 with the conveyor belt drive roller 42. In the figure, as the conveyor belt cleaning device 44, a system in which toner is scraped off from the belt by a rotating fur brush 44a is shown, but a system in which the toner is scraped off by a cleaning blade may be used.

  The fixing device 50 forms a fixing nip by rotating a fixing roller 51 containing a heat source such as a halogen lamp and a pressing roller 52 pressed against the fixing roller 51 in the forward direction. Then, the transfer paper P received from the conveyance belt 41 is sandwiched between the fixing nips and is pressurized while being heated. Under the influence of the heating and pressurization, the toner is softened and the toner image is fixed on the transfer paper P. The transfer paper P that has passed through the fixing device 50 is discharged to the outside of the apparatus through a pair of paper discharge rollers 60 or is sent to a paper reversing unit (not shown) disposed below the fixing device 50.

  Next, the protective agent supply means, which is a characteristic part of the printer of this embodiment, will be described. FIG. 29 is a schematic configuration diagram of a printer provided with a conventional protective agent supply means. In a conventional printer, the protective agent is generally supplied to the photosensitive member 1 at one place. FIG. 29 shows an example in which a protective agent supply means 135 is provided upstream of the cleaning blade 2. In addition, as described in Patent Document 2 described above, there is a type in which a protective agent supply unit is provided downstream of the cleaning blade 2 and upstream of the charging roller 111. However, when the protective agent is supplied to the photoconductor 1 at one place, in any case, the supply amount may be biased in the axial direction over time. In addition, if the supply of the protective agent to the photosensitive member 1 is performed at a single location, the photosensitivity by discharge is performed regardless of whether the supply location is upstream of the cleaning blade 2 or downstream of the cleaning blade 2 and upstream of the charging device 220. It is difficult to achieve both suppression of deterioration of the body 1 and suppression of increase in the amount of toner passing through.

  FIG. 4 is a perspective view illustrating a printer including a plurality of protective agent supply units according to the present embodiment. In the printer shown in FIG. 4, since the protective agent is supplied to the photoreceptor 1 at two locations, two protective agent supply means 135A and 135B are provided. The protective agent supply means 135A and 135B are respectively rotatable fur brushes 136A and 136B as supply members arranged so as to be in contact with the surface of the photoreceptor 1, and solid protective agents 137A and 137B molded into solid bars. And a pressure spring (not shown) for pressing the solid protective agents 137A and 137B against the fur brushes 136A and 136B. Here, in 135A which is one of the protective agent supply means, for example, it is assumed that the fur brush 136A and the solid protective agent 137A are in strong contact with each other on the back side in FIG. In this case, the amount of supply onto the surface of the photoreceptor 1 immediately after passing through the protective agent supplying means 135A is large on the back side and decreases on the near side, and is biased in the axial direction. Next, when the surface of the photoreceptor 1 coated with the protective agent by the protective agent supply unit 135A reaches the protective agent supply unit 135B, the supply amount of the protective agent supplied from the protective agent supply unit 135B is small on the back side, Increase on the front side. For this reason, as a result, the amount of the protective agent present on the surface of the photoreceptor 1 after passing through the protective agent supply means 135B is equal to the amount of the protective agent on the surface of the photoreceptor 1 after passing through the protective agent supply means 135A. More uniform than quantity bias. This is considered to be due to the property that even if an attempt is made to stack a material having lubricity on the material having lubricity such as zinc stearate, the material does not accumulate more than a certain level. That is, in the protective agent supply unit 135B, compared to the front side where the protective agent is small on the photosensitive member 1, the far side where a large amount of protective agent is supplied is scraped off from the solid protective agent 137B and is applied to the fur brush 136A. It is difficult for the protective agent adhering to the surface to move onto the photoreceptor 1. In this way, even when the fur brush 136A and the solid lubricant 137A are initially biased and abutted in the protective agent supplying means 135A, there is a difference in the supply amount of the protective agent on the surface of the photoreceptor 1. The bias of the supply amount of the protective agent after passing through the protective agent supply means 135A is reduced by changing the amount of the protective agent supplied by the protective agent supply means 135B depending on the amount of the protective agent on the surface of the photoreceptor 1. Can do.

  Further, in the printer 200 of the present embodiment, a plurality of protective agent supply means are provided at specific locations, so that the deterioration of the photosensitive member 1 due to the proximity discharge can be suppressed, and the toner passing through the cleaning blade 2 due to the deteriorated protective agent can be prevented. Achieving both suppression of volume increase. FIG. 5 is a schematic configuration diagram of a printer in which a plurality of protective agent supply means are provided at specific locations. In this printer 200, as shown in FIG. 5, the supply of the protective agent to the photoreceptor 1 is performed downstream of the cleaning blade 2 and upstream of the charging roller 111 and downstream of the charging roller 111. Thus, the cleaning is performed at two locations with the second supply region 160 upstream of the cleaning blade 2. As shown in FIG. 5, the first protective agent supply means 151 that supplies the protective agent to the first supply region 150 downstream of the cleaning blade 2 and upstream of the charging roller 111 is disposed downstream of the charging roller 111. 2 is provided with a second protective agent supply means 161 for supplying a protective agent to the second supply region 160 upstream of 2. By supplying the protective agent to the first supply region 150 by the first protective agent supply means 151, the protective agent is not partially removed from the photoreceptor 1 before reaching the discharge region of the charging roller 111, The photoreceptor 1 is in a state where a uniform protective layer is formed when passing through the discharge region of the charging roller 111. Therefore, it is possible to effectively prevent the surface of the photoreceptor 1 from being deteriorated due to the proximity discharge. Further, by supplying the protective agent to the second supply region 160 by the second protective agent supply means 161, the protective agent is newly deteriorated on the protective agent supplied in the first supply region 150 and deteriorated when passing through the charging roller 111. Supply no protective agent. As a result, after passing through the second protective agent supply means 161, the deteriorated protective agent is hardly exposed on the photoconductor 1, and when passing through the cleaning blade 2, it deteriorates between the photoconductor 1 and the cleaning blade 2. The protective agent is difficult to intervene directly.

  The inventors have confirmed through experiments shown in Table 1 that an increase in the amount of slip-through toner is suppressed by recoating the protective agent on the deteriorated protective agent.

  In condition 1 of Table 1, the amount of toner slipping was measured when zinc stearate or deteriorated zinc stearate was not present on the photoreceptor surface (no effect) (sample name is described as (CTL) in Table 1). . That is, as shown in FIG. 10, while the image pattern was continuously developed on the photoconductor 1 by the developing device 120, the operation of removing the image pattern from the photoconductor 1 by the cleaning blade 2 was performed for 20 rotations of the photoconductor. At that time, the amount of slipping toner that passed through the cleaning blade 2 and remained on the photoreceptor 1 was measured. For the measurement of the slipping toner, a felt-like toner capturing member is brought into contact with the photoreceptor 1 downstream of the cleaning blade, and the slipping toner is captured. Was used. In this experiment, the transfer device is separated from the photosensitive member, and the toner developed on the photosensitive member 1 by the developing device 120 reaches the cleaning device as it is. This also applies to the following conditions 2, 3, 4, and 5.

  Under condition 2 in Table 1, the amount of toner slipping was measured when zinc stearate that had not deteriorated due to discharge was present on the surface of the photoreceptor (the sample name was described as (ZnST) in Table 1). As shown in FIG. 11A, the photosensitive member 1 was rotated 20 times while applying zinc stearate in a state where the fur brush 136 for applying zinc stearate was not in contact with the photosensitive member 1. After that, as shown in FIG. 11B, the developing device 120 and the cleaning blade 2 were placed in contact with the photosensitive member 1, and then the amount of slip-through toner was measured in the same manner as in Condition 1.

  In condition 3 of Table 1, the amount of toner slipping was measured when zinc stearate deteriorated by discharge was present on the surface of the photoreceptor (the sample name was described as (degraded ZnST) in Table 1). As shown in FIG. 12A, the operation of applying the zinc stearate onto the photosensitive member 1 while discharging the charging roller 111 by applying a bias in which the AC voltage is superimposed on the DC voltage is rotated 20 times on the photosensitive member 20. I went for a minute. Due to this operation, deteriorated zinc stearate that has deteriorated due to discharge exists on the photoreceptor 1. Thereafter, as shown in FIG. 12B, the developing device 120 and the cleaning blade 2 were placed in contact with the photoreceptor 1, and the amount of slip-through toner was measured in the same manner as in Conditions 1 and 2.

  In the condition 4 of Table 1, when the zinc stearate that has not deteriorated is overcoated on the deteriorated zinc stearate for 20 rotations of the photoreceptor (sample name is described as (overcoat × 20) in Table 1), The amount of toner was measured. First, after a deteriorated zinc stearate layer is provided on the photoreceptor 1 by the same method as in Condition 3, the zinc stearate is supplied without the charging operation as shown in FIG. The photoconductor was rotated 20 times while applying the film. Thereby, it will be in the state by which the zinc stearate which has not deteriorated was apply | coated on the deterioration zinc stearate layer. Thereafter, as shown in FIG. 13B, the developing device 120 and the cleaning blade 2 were placed in contact with the photosensitive member 1, and the amount of slip-through toner was measured in the same manner as in Conditions 1, 2, and 3.

  Under condition 5 in Table 1, when the zinc stearate that has not deteriorated is overcoated on the deteriorated zinc stearate for 40 rotations of the photoreceptor (in Table 1, the sample name is described as (overcoat × 40)) The amount of toner was measured. The only difference from condition 4 is that the amount of zinc stearate applied on the deteriorated zinc stearate is increased.

  FIG. 14 shows the amount of toner passing through as an experimental result of conditions 1 to 5 in Table 1. In FIG. 14, the above-mentioned “slip-through toner ID” is plotted on the vertical axis, and the larger the ID value, the greater the slip-through amount and the lower the cleaning property. In FIG. 14, the fact that the amount of slipping through condition 2 (ZnST) is smaller than that in condition 1 (CTL)) is present between the photosensitive member 1 and the cleaning blade 2 in a state where the zinc stearate is not deteriorated. This indicates that there is an effect of improving the cleaning property. On the other hand, in the case of condition 3 (degraded ZnST), the amount of slip-through toner is remarkably increased, and when deteriorated zinc stearate is interposed between the photoreceptor 1 and the cleaning blade 2, the cleaning property is deteriorated. I understand that. On the other hand, in conditions 4 and 5 in which zinc stearate is overcoated from deteriorated zinc stearate, the amount of slip-through toner is reduced as compared with condition 3. Further, the fact that the amount of slip-through toner in Condition 5, which has a large number of overcoating operations, is further reduced as compared with Condition 4, indicates the following. That is, in condition 5 where the number of top coatings is large, undegraded zinc stearate covers the deteriorated zinc stearate layer in a wider area than condition 4, and the contact area between the cleaning blade and the deteriorated zinc stearate is large. It shows that it is less. According to the comparative experiments under the above conditions 1 to 5, even when zinc stearate deteriorated by proximity discharge is present on the surface of the photoreceptor 1 after the repeated image forming process, the deterioration occurs from above the deteriorated zinc stearate. It can be seen that the frequency of contact between the deteriorated zinc stearate and the cleaning blade can be reduced by overcoating the uncoated zinc stearate, thereby suppressing the amount of toner passing through. Therefore, it is possible to achieve both suppression of deterioration due to proximity discharge of the photoreceptor 1 and suppression of increase in the amount of toner passing through the cleaning blade 2 due to the deteriorated protective agent.

  Next, the 1st protective agent supply means 151 and the 2nd protective agent supply means 161 are demonstrated concretely. The printer shown in FIG. 5 has a configuration in which two protective agent supply means, a first protective agent supply means 151 and a second protective agent supply means 161, are directly disposed on the surface of the photoreceptor 1. The first protective agent supply means 151 includes a rotatable fur brush 152 as a supply member disposed so as to contact the first supply region 150, a solid protective agent 153 molded into a solid bar shape, and a solid protective agent And a pressure spring 154 that presses the fur brush 152 against the fur brush 152. The second protective agent supply means 161 includes a rotatable fur brush 162 as a supply member disposed so as to contact the second supply region 160, a solid protective agent 163 molded into a solid bar shape, And a pressure spring 164 that presses the protective agent 163 against the fur brush 162. The fur brushes 152 and 162 are rotated, and the pressed solid protective agents 153 and 163 are applied onto the photoconductor 1 while scraping off, whereby the protective agent is applied to the first supply region 150 and the first supply region of the photoconductor 1 respectively. Supply to the second supply area 160. In the second protective agent supply unit 161, the rotation direction of the fur brush 162 is set to the counter direction with respect to the rotation direction of the photoconductor 1. This is because when the toner is adhered to the fur brush 162 by setting the counter direction, the solid protective agent 163 plays the role of flicker, and the toner does not enter the second supply region 160. When the toner enters the second supply region 160, the toner becomes an obstacle and the application of the protective agent becomes unstable.

  Further, as shown in FIG. 5, the protective agent applied by the first protective agent supply unit 151 is stretched downstream of the first protective agent supply unit 151 and upstream of the charging roller 111 to form a more uniform protective layer. A stretching member may be provided. As the stretching member, a blade-shaped stretching blade 170 used for a cleaning blade or the like is used. Further, by arranging the stretching blade 170 in the trailing direction with respect to the photosensitive member 1, it is possible to reduce the load on the photosensitive member 1 as compared with the case where it is arranged in the counter direction.

  Further, as a modification of the protective agent supply means, in addition to the method of applying the protective agent to the photoreceptor 1 with a fur brush pressed against the solid protective agent, a powdery protective agent retention region is provided to provide the protective agent with the photoreceptor. There is also a method of supplying up to 1. FIG. 6 is a schematic configuration diagram of a printer including a protective agent supply unit provided with a powdery protective agent retention region. As shown in FIG. 6, the powder is surrounded by a stretching blade 170 and a partition member 156 for preventing leakage and scattering of the powdery protective agent 157 so as to face the first supply region 150 of the photoreceptor 1. A first protective agent retention region 155 that houses the protective agent 157 is provided. Further, the powdery protective agent 167 is accommodated by being surrounded by the cleaning blade 2 and a partition member 166 for preventing leakage and scattering of the powdery protective agent 167 so as to face the second supply region 160 of the photoreceptor 1. A second protective agent retention region 165 is provided. With this configuration, when the photoreceptor 1 passes through the first protective agent retention region 155 and the second protective agent retention region 165, the protective agent is supplied to the first supply region 150 and the second supply region 160. Is done. In FIG. 6, the partition member 156 is provided upstream of the stretching blade 170 in the first protective agent retention region 155, but the cleaning blade and the stretching blade 170 are used together as a partition member. May be formed.

  Next, a modification of the printer of this embodiment will be described. In recent years, with the progress of miniaturization of printers, it may be difficult in terms of layout to provide two protective agent supply means facing the photoreceptor 1 as shown in FIG. In such a case, the supply of the protective agent to the second supply region 160 may be performed by means other than the second protective agent supply means 161 including the fur brush 162 and the solid protective agent 163 facing the photoreceptor 1. .

  For example, as shown in FIG. 7, a plurality of photoconductors and a toner image forming unit on each photoconductor are arranged in parallel with respect to the belt-shaped intermediate transfer body 45 and formed on the plurality of photoconductors. The toner image is used in a so-called tandem type color printer that superimposes toner images on an intermediate transfer member 45 to form a color image. In the case of an image forming apparatus using the intermediate transfer member 45 such as a tandem color printer, the supply of the protective agent to the second supply region 160 is a second protective agent supply provided so as to face the intermediate transfer member 45. This is done by means 161. A protective agent is supplied onto the intermediate transfer member 45 by the second protective agent supply means 161. At the opposing portion of the intermediate transfer body 45 and each photoconductor, that is, at the primary transfer position, the intermediate transfer body 45 and each photoconductor are in contact with each other, and the protective agent on the intermediate transfer body 45 is transferred to each photoconductor. . In this manner, the protective agent is supplied to the second supply region 160 of each photoconductor via the intermediate transfer member 45. The second protective agent supply means 161 includes a rotatable fur brush 162 having the same form as in FIG. 4 described above, a solid protective agent 163 obtained by solidifying the protective agent, and an additive that presses the solid protective agent 163 against the fur brush 162. It consists of a pressure spring 164. Thus, in a printer having a plurality of photoconductors, a plurality of second protective agent supply means are not provided so as to face each photoconductor, but a second one facing the intermediate transfer body 45 facing each photoconductor. By providing one protective agent supply means, the protective agent can be supplied to the second supply regions of the plurality of photoconductors. Therefore, it is possible to save space around the photoreceptor and reduce the number of parts.

  In FIG. 7, one second protective agent supply means is provided so as to face the intermediate transfer member 45. However, there is a margin in the layout around the intermediate transfer member 45, and the four photosensitive members are sufficiently protected. As shown in FIG. 8, four protective agent supply means can be provided so as to face the intermediate transfer body 45 immediately upstream of the primary transfer position with each photoconductor.

  Moreover, the other modified example of the 2nd protective agent supply means 160 is demonstrated using FIG. As the second protective agent supply means, there is a method using a toner containing a protective agent instead of a fur brush and a solid protective agent. FIG. 9 is a schematic configuration diagram of a toner using a protective agent internally added as the second protective agent supply means. In the printer of FIG. 9, it is not necessary to provide a separate device other than the first protective agent supply unit 151 including the fur brush 152 and the solid protective agent 153 to the first supply region, and the toner also serves as the second lubricant supply unit. . For this reason, space saving of an apparatus can be achieved. The toner internally added with the protective agent is developed on the photosensitive member 1 and then transferred to the transfer material in the transfer device 40. However, since the protective agent is transferred onto the photosensitive member 1, it deteriorates in the discharge region. The protective agent transferred from the toner forms a protective layer on the protective agent.

  Next, the fur brushes 152 and 162 and the solid protective agents 153 and 163 used in the protective agent supply means 151 and 161 will be described.

  The fur brushes 152 and 162 are roller-like brushes in which an infinite number of acrylic carbon raised brushes are planted on the core material. Innumerable raised tips (not shown) are rotationally driven in the clockwise direction in the figure, which causes surface movement in the counter direction at the portion facing the photoreceptor 1 so that the photoreceptor 1 is sequentially rubbed. By this rotational drive, the lubricant powder scraped from the lubricant solids 153 and 163 is applied to the surface of the photoreceptor 1 or the surface of the intermediate transfer member 45.

  If the solid protective agents 153 and 163 are directly rubbed against the photoconductor 1 without providing the fur brushes 152 and 162, the solid protective agents 153 and 163 may be unevenly worn, or the surface of the photoconductor 1 or the intermediate transfer body 45 may be used. In addition, the coating amount of the lubricant powder becomes uneven. Accordingly, the lubricant powder is scraped off from the solid protective agents 153 and 163 by the fur brushes 152 and 162 and applied to the surface of the photoreceptor 1 or the intermediate transfer member 45. With such a configuration, the above-described uneven wear and uneven application amount can be suppressed.

  Further, when the fur brushes 152 and 162 are used, it is possible to easily adjust the amount of the lubricant powder applied to the surface of the photoreceptor 1 or the intermediate transfer body 45 by adjusting the rotation speed.

  As the solid protective agents 153 and 163, those obtained by solidifying metal soap such as zinc stearate, calcium stearate, magnesium stearate, barium stearate, and aluminum stearate can be used. It is also preferable to use a lamellar crystal powder such as zinc stearate. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. This action is considered effective. In addition, it is also possible to use other substances such as various fatty acid salts, waxes, and silicone oils as protective agents.

  Examples of fatty acids include undecyl acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, pendadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, arachidonic acid, caprylic acid, capric acid, caproic acid, etc. Examples of the metal salt include salts with metals such as zinc, iron, copper, magnesium, aluminum, and calcium.

  Next, a photoconductor cleaning device employed in the printer of this embodiment will be described in comparison with a conventional photoconductor cleaning device. First, a cleaning device in a conventional printer will be described. FIG. 15 is a schematic view showing the holder 132 and the cleaning blade 2 in the conventional photoconductor cleaning device 130. In the same figure, a holder 132 as a beam member is cantilevered by being fixed to a casing at one end side in a region not shown. On the free end side of the holder 132, the cleaning blade 2 is fixed so as to protrude from the tip of the holder 132. Then, the protruding edge E is brought into contact with the photosensitive member 1 (not shown), and the transfer residual toner on the surface of the photosensitive member 1 is scraped off. The cleaning blade 2 is made of polyurethane rubber as a soft member for the purpose of improving the adhesion with the photoreceptor 1. Therefore, when the edge E of the tip is pressed while being in contact with the photosensitive member 1, the tip side protruding from the holder 132 is slightly bent as shown in the figure. When cleaning the toner by the conventional pulverization method, it is sufficient to press the toner with a relatively weak pressing force.

  In recent years, for the purpose of enabling the formation of higher-resolution images, development of printers that form images using toner by a polymerization method having a small particle diameter and excellent sphericity instead of toner by a pulverization method has progressed. It has been. By using the toner by the polymerization method, it is possible to form a high quality image with little dot shape disturbance. However, if the toner has a small particle size or a spherical shape, it becomes difficult to completely remove the transfer residual toner using the cleaning blade 2, and cleaning failure occurs. This is because a rotational moment is generated in the toner at the position where the cleaning blade 2 is pressed against the photosensitive member 1, and the cleaning blade 2 is pushed up so that the toner is easily caught between the cleaning blade 2 and the photosensitive member 1. For this reason, in the case of using a toner whose particle size has been reduced or spheroidized, it is necessary to increase the pressing force of the cleaning blade 2 against the photosensitive member 1 to prevent the toner from trapping. When the cleaning blade 2 is pressed toward the photoconductor 1 with a strong pressing force that can clean the toner by the polymerization method, the leading end side of the cleaning blade 2 is greatly bent.

  FIG. 16 is an enlarged view showing a tip portion of a conventional cleaning blade 2 pressed against the photoreceptor 1 with a strong pressing force capable of satisfactorily cleaning the toner by the polymerization method. The surface of the photoreceptor 1 moves from the right side to the left side in FIG. In the cleaning blade 2 shown in the same figure, a portion surrounded by a symbol E indicates an edge in contact with the photosensitive member 1. As shown in the figure, the edge E that is in contact with the photosensitive member 1 sinks under the surface of the cleaning blade 2 facing the photosensitive member 1 so as to bend along the photosensitive member surface movement direction. This wrinkle is formed with a size of about several μm and appears even when the pressing force is weak when cleaning the toner by the pulverization method. However, conventionally, the blade portion in contact with the photosensitive member 1 is only the edge E that slightly swells with a size of several μm. However, the cleaning blade 2 pressed toward the photosensitive member 1 with a strong pressing force is greatly bent, so that not only the edge E but also a surface facing the photosensitive member 1 is shown as surrounded by Bs in the drawing. A so-called belly contact with the photoreceptor 1 is achieved. In this state, the frictional force between the cleaning blade 2 and the photosensitive member 1 is excessively increased, the torque for rotating the photosensitive member 1 is increased, and the photosensitive member 1 is driven to rotate favorably. It becomes difficult.

  FIG. 17 is a pressure distribution diagram at the tip of the cleaning blade 2 in the state shown in FIG. In the same figure, the pressure distribution line is located on the lower side in the figure, indicating that a stronger pressure is applied to the cleaning blade. In order to clean the toner by the polymerization method satisfactorily, it is only necessary to obtain the contact pressure having the strength indicated by the longest arrow in the drawing at the contact portion between the edge E of the cleaning blade 2 and the photosensitive member 1. However, in the conventional cleaning blade 2, when the contact pressure between the edge E of the cleaning blade 2 and the photosensitive member 1 is obtained, the contact with the abdomen as shown in FIG. Pressure is generated. As a result, it has been found that the load of the cleaning blade 2 on the photosensitive member 1 is increased, the rotational torque of the photosensitive member 1 is increased, and this is a major cause of hindering favorable rotational driving of the photosensitive member 1.

  Conventionally, as a characteristic value representing the force for preventing the toner from entering the contact portion between the cleaning blade 2 and the photosensitive member 1, the total load applied to the cleaning blade 2 is divided by the length of the ridgeline of the cleaning blade 2. It was common to use a linear pressure ([N / cm]) that was a high value. Specifically, this linear pressure is a value obtained as follows. That is, a sheet-shaped sensor having a thickness of 0.1 [mm] is sandwiched between the contact portion between the photoreceptor 1 and the cleaning blade 2, and the output value of the sensor (load [g] acting on the contact portion) is set as the photoreceptor. It is a value divided by the length ([cm]) of the contact portion in the axial direction. At the time of measuring the linear pressure, the cleaning blade 2 is brought into contact with the photosensitive member 1 so as not to bend the blade edge. The sheet-like sensor has a large number of electrodes arranged in two directions (row direction and column direction) orthogonal to each other, and the surface thereof is covered with a film resin. In these electrodes, a pressure-sensitive resistance material and a charge generation material are arranged in a lattice shape, and when an external pressure is applied to the intersection of the lattice shape, the resistance value changes according to the load. This change in resistance value appears as a change in the current value flowing in the row direction and the column direction, so that the total load is obtained from the current value.

  However, it was found that the characteristic value of the linear pressure cannot sufficiently evaluate the ability to prevent the toner from coming into the contact portion. The linear pressure is a value obtained by dividing the load acting on the contact portion between the blade and the photosensitive member by the length of the contact portion in the axial direction of the photosensitive member. This is because the portion is formed and is in contact with the surface instead of the line. Even when the same load is applied to the cleaning blade 2, the contact area between the cleaning blade 2 and the photoreceptor 1 (nip width) varies depending on the hardness, thickness, free length, shape, etc. of the rubber blade. The obtained load per unit area is different from the actual contact pressure.

  For example, even when the same load (linear pressure) is applied to two types of cleaning blades having the same blade material characteristics such as blade hardness and different shapes, the contact pressure and the linear pressure are different.

  FIG. 18 is an enlarged configuration diagram showing the cleaning blade 2 having a shape that is less likely to bend with respect to a certain load than the cleaning blade 2 shown in FIG. In the drawing, a cleaning blade 2 as a plate-like elastic body has a thick portion 2a that is partially thick in a region from the rear end side toward the front end side. The cleaning blade 2 is fixed to the back surface of the holder 132 in a state where the side surface on the rear end side of the thick portion 2 a is in close contact with the front end of the holder 132. The thick part 2 a is in a state of protruding from the tip of the holder 132.

  In the cleaning blade 2 having the shape shown in FIG. 18, the protruding portion from the tip of the holder 132 is the thick portion 2 a, so that the protruding portion is larger than the blade having the same thickness on the leading end side as the rear end side. Becomes difficult to bend. In addition, when the front end side is bent, the side surface on the rear end side of the thick portion 2 a is strongly pressed against the front end of the holder 132. This also makes the tip side difficult to bend.

  FIG. 19 shows the cleaning shown in FIG. 11 in which the edge E is strongly brought into contact with the photoconductor 1 so that the contact pressure with the photoconductor 1 per unit area is strong enough to clean the toner by the polymerization method. FIG. 3 is an enlarged view showing a tip portion of a blade 2. As shown in FIG. 19, in the cleaning blade 2 provided with the thick portion 2a, the thick portion 2a greatly suppresses the deflection on the tip side, so as shown in FIG. Only E is brought into contact with the photoreceptor 1. For reference, the pressure distribution is shown in FIG. It can be seen that a strong pressure is intensively applied to the edge in contact with the photoreceptor 1.

  In the cleaning blade 2 shown in FIG. 18, the load is not dispersed due to the contact with the belly, so that the pressure is concentrated on the tip of the cleaning blade 2 and becomes a large pressure vector. Therefore, even when the same load is applied, the contact state (contact area) between the cleaning blade 2 and the photosensitive member 1 changes due to the different blade shapes, the surface pressure distribution varies greatly, and the cleaning properties also differ. I can see it coming. Therefore, the conventionally used characteristic value of linear pressure [N / cm] cannot accurately represent the cleaning performance in blade cleaning. Spherical toner cannot always be cleaned simply by increasing the linear pressure [N / cm], but there is a possibility that the photoreceptor driving torque will increase or breakage may occur. Accordingly, the present inventors have decided to evaluate the cleaning performance using a contact pressure that is a pressure per unit area as a new characteristic value. The surface pressure is a value obtained by dividing the total load applied when the cleaning blade 2 is pressed against the photosensitive member 1 by the contact area between the cleaning blade 2 and the photosensitive member 1. The contact area between the cleaning blade 2 and the photosensitive member 1 can be easily obtained by measuring the contact area when the cleaning blade 2 is pressed against the transparent pseudo-photosensitive member.

[Experiment 1] With respect to the surface pressure required for cleaning the spherical toner, the cleaning blade 2 is contacted with the edge 1 of the cleaning blade 2 having the shape shown in FIG. An experiment to investigate was conducted. The experimental conditions are listed below.
-Photoconductor diameter: 30 [mm]
-Photoconductor linear velocity: 185 [mm / sec]
The length of the image forming area A4 in the main scanning direction of the photoconductor = 300 [mm]
The length including the non-image forming area in the main scanning direction of the photoconductor = 340 [mm]
-Thickness tb of the blade holder fixing portion: 1.7 [mm]
-Thickness ta of the thick part 2a of the blade: 3.5 [mm]
-Length Ld of the thick part 2a: 3.8 [mm]
-The length Le of the thin part of the blade tip Le: 1.2 [mm]
-Total length Lc of the same thin portion and the tapered portion: 7 [mm]
-Blade total length Lf: 11 [mm]
-Holder thickness: 1.8 [mm]

  The cleaning property was measured as follows. That is, the actual machine that is printing out the reference image is temporarily stopped, and the adhesive tape is affixed to and peeled from the surface of the photoreceptor after cleaning to transfer the residual toner after cleaning to the adhesive tape. Then, the image density (ID) of this adhesive tape was measured by a well-known technique to obtain a residual toner ID. The higher the residual toner ID value, the more cleaning residual toner is attached to the surface of the photoreceptor after cleaning, that is, the cleaning property is deteriorated.

  Further, the contact pressure per unit area between the edge of the cleaning blade 2 and the photosensitive member 1 was measured as follows. First, a transparent glass tube having the same curvature as that of the photoreceptor 1 is prepared, and this is set in an actual machine. Then, the cleaning grade 2 is brought into contact therewith, and the weight F per unit length (in the drum axis direction) is measured by an I-SCAN weight measuring device (manufactured by Nitta Corporation). Next, the back side of the cleaning blade 2 is photographed through a transparent glass tube. Based on the photographed image, the contact width (length in the surface movement direction) W between the cleaning blade 2 and the transparent glass tube is obtained. Based on the weight F and the contact width W, the contact pressure per unit area was obtained. Finally, the transparent glass tube was replaced with the photoconductor 1, and the cleaning blade 2 was brought into contact with the photoconductor 1 so that the same weight F as that of the transparent glass tube was obtained, and a reference image was output. Of course, a reference image was output using a toner formed by a polymerization method.

The results of Experiment 1 are shown in Table 2 below. Note that the cleaning property in Table 2 was divided into the following five ranks based on the remaining toner ID.
◎ (Rank 5): Completely cleaned ○ (Rank 4): Slightly residual toner △ (Rank 3): When a streaky cleaning defect occurs partially or a small amount of toner remains on the entire surface X (rank 2): Streaky or large amount of toner remains on the entire surface

  As shown in Table 2, in this experiment 1, the linear pressure was 0.40 to 1.20 [N / cm], the contact width (contact length in the surface movement direction) was 5 to 90 [μm], Each was varied. When a linear pressure of 1.20 [N / cm] was applied to the blade, good cleaning properties (◎ or ○) were obtained in the contact pressure range of 2.0 to 12 [MPa]. If the surface pressure is too high at 24 [MPa], a cleaning failure has occurred. This is for the reason described below. In other words, since the contact width is as narrow as 5 [μm], contact unevenness occurs in the main scanning direction due to a photoconductor accuracy error and the like, and there is a portion where a sufficient contact pressure is not exerted partially. Conceivable.

  When a linear pressure of 0.95 [N / cm] is applied to the blade, good cleaning properties are obtained with a contact pressure of 3.17 to 9.5 [MPa]. However, when the contact pressure is increased to 19 [MPa], the contact width becomes as narrow as 5 [μm]. If the contact pressure is 1.9 [MPa] or less, a cleaning failure due to insufficient pressure occurs.

  When a linear pressure of 0.40 [N / cm] is applied to the blade, a good cleaning property is obtained with a surface pressure of 2.0 to 4.0 [MPa]. However, when the surface pressure increased to 8.0 [MPa], cleaning failure due to uneven contact occurred. Further, in contact with 1.33 [MPa] or less, a cleaning failure due to insufficient pressure occurred.

  From the results of Table 2, it was found that the spherical toner can be cleaned well by setting the surface pressure to 2.0 [MPa] or more. However, when the contact width was about 10 [μm] or the contact pressure was 2.0 [MPa], the toner remained slightly (◯), and the cleaning was not complete. As the contact area is reduced, a higher surface pressure can be applied. However, if the contact width between the cleaning blade 2 and the photosensitive member 1 is too narrow, contact unevenness with the photosensitive member and scratches on the surface of the photosensitive member are caused. This is because cleaning defects are likely to occur due to protrusions and the like. Therefore, in order to clean the spherical toner, the surface pressure is set to 2.0 [MPa] or more, preferably 3.0 [MPa] or more, and the contact width is set to 10 [μm] or more.

  In order to suppress film scraping of the photosensitive member 1, increase in photosensitive member driving torque, blade wear, and the like, it is desirable to set the contact width to 10 to 40 [μm]. Further, it is preferably 30 [μm] or less. When the contact width is larger than this (for example, 100 μm), if the surface pressure is 2.0 [MPa] or more, and further 3.0 [MPa] or more, it prevents the spherical toner from being caught by the polymerization method, Although it can be cleaned well, it is possible. However, for example, in order to make the surface pressure 2.0 [MPa] with a contact width of 100 μm, a linear pressure of 2.0 [N / cm] must be applied, and a very large linear pressure is required. turn into. And, due to the synergistic effect of such a high linear pressure and the size of the contact width, the frictional force at the contact portion is excessively increased. It is important to clean the toner well with as little contact pressure as possible. In order to prevent the spherical toner from coming into the contact portion by the polymerization method, the contact width between the photoreceptor 1 and the blade is set to 10 [μm in consideration of the assembly accuracy of the photoreceptor 1 and the toner particle size. It is preferable to set it above. And the upper limit needs to be 40 micrometers or less, Preferably it is 30 micrometers or less. By setting such a contact width, it is possible to realize such a contact width and a contact pressure of 2.0 [MPa] or more with a linear pressure of 0.20 to 1.20 [N / cm]. it can.

  Next, the configuration of the cleaning blade 2 employed in the printer 200 of this embodiment will be described. As the cleaning blade 2, a conventionally used cleaning blade having a blade tip cut surface of 90 ° can be used. However, by adopting a cleaning blade having an obtuse shape at the blade tip, spherical toner can also be used. Applicable and good cleaning performance can be maintained. FIG. 22 is an explanatory diagram of a blade shape in which the leading edge ridge line portion included in the photoconductor cleaning device 130 of the printer 200 has an obtuse angle. As shown in FIG. 22, the base end of the cleaning blade 2 as an elastic blade is attached to one side of a holder 132 as a support member. The leading edge portion 21 of the cleaning blade 2 is pressed against the peripheral surface of the photoconductor 1 as an image carrier.

As shown in FIG. 22, the length from the stepped portion between the holder 132 and the cleaning blade 2 to the tip ridge line portion 21 is the blade free length t2, and the thickness of the cleaning blade 2 is the blade thickness t1. At this time, the cleaning blade 2 has a shape that satisfies the following relationship between the blade free length t2 and the blade thickness t1.
1.75 ≦ t2 / t1 ≦ 3.00
As a result of intensive studies by the present inventors, it is possible to prevent buckling at the joint between the holder 132 as a support plate and the cleaning blade 2 as an elastic member by satisfying the above relational expression. I understood. FIG. 21 is an explanatory diagram of a blade shape in which a tip ridge line portion of a conventional cleaning blade is a right angle. The shape of the cleaning blade 2 was, for example, a blade free length t2 = 7 mm, a blade thickness t1 = 2 mm, and t2 / t1 = 3.5. With such a shape, the cleaning blade 2 is buckled at the joint with the holder 132 and hits the belly, so that the surface pressure necessary for cleaning the spherical toner could not be applied. On the other hand, by setting the shape of the cleaning blade 2 so that the blade free length t2 and the blade thickness t1 satisfy the above relational expression, buckling at the joint between the cleaning blade 2 and the holder 132 can be suppressed. I can do it.

  The cleaning blade 2 uses, for example, a rubber having a JISA hardness of 60 [°] or more and 80 [°] or less. When the hardness is less than 60 [°], even when the blade thicknesses t1 and t2 satisfy the above relationship, buckling occurs at the joint between the support plate and the elastic body, and sufficient surface pressure is applied. There are cases where it is not possible. On the other hand, when the rubber hardness is too high, the adhesion with the photoreceptor is deteriorated, and a place where a sufficient surface pressure is not partially applied may occur, resulting in poor cleaning. Further, a material having a rebound resilience of 30% or less at 23 ° C. is used.

  The angle θ that forms the tip ridge line portion 21 of the cleaning blade 2 is an obtuse angle. The obtuse angle is preferably in the range of 95 [°] to 140 [°]. The toner removal performance and the surface pressure of the cleaning blade 2 are as described above. When the tip angle of the cleaning blade 2 is an obtuse angle, the tip edge portion 21 is a right angle, that is, θ = 90 [°]. Compared with the cleaning blade 2, a higher surface pressure can be applied with a lower linear pressure. Hereinafter, the angle θ that forms the tip ridge line portion 21 of the cleaning blade 2 will be described in detail in comparison with a conventional cleaning blade.

  The edge portion of the conventional cleaning blade has a 90 [°] angle formed by the cut surface, which is the tip surface of the cleaning blade 2, and the air surface, which is the lower surface of the cleaning blade 2, in the entire longitudinal width of the cleaning blade 2. . This is because when the blade tip surface is perpendicular to the blade lower surface and the blade upper surface, it is easier to process the blade. FIG. 27 shows a schematic view of a cleaning blade having a right-angled tip ridge. FIG. 27A is an overall view of the cleaning blade 2, and FIG. 27B is a view in the vicinity of the leading edge portion 21 where the cleaning blade 2 abuts on the photosensitive member 1 as an image carrier. 3 is an enlarged view of a region C. FIG.

  When the tip ridge 21 is brought into contact with the photoreceptor 1 moving at a right angle in the direction of arrow D in the figure, it is pulled in the direction of arrow D by the frictional force with the photoreceptor 1, and as shown in FIG. The turn over at the part 21 becomes large. When the turning is increased, the contact length in the direction of arrow D between the cleaning blade 2 and the surface of the photoconductor 1 is increased, and the area where the cleaning blade 2 and the surface of the photoconductor 1 are in contact with each other is increased. Even if the predetermined load is applied to the photosensitive member 1 from the cleaning blade 2, the contact pressure decreases if the area where the cleaning blade 2 contacts the surface of the photosensitive member 1 is large. If the surface pressure is low, it is not possible to sufficiently prevent the toner from slipping through the contact portion, resulting in poor cleaning. Here, when the load on the photosensitive member 1 of the cleaning blade 2 is increased in order to increase the surface pressure, there arises a problem that the torque for moving the surface of the photosensitive member 1 increases and the load on the drive system increases.

  Therefore, the cleaning blade 2 is improved by making the angle of the tip ridge line portion an obtuse angle. FIG. 28 shows a schematic view of a cleaning blade having an obtuse angle at the tip ridge line portion. FIG. 28A is an overall view of the cleaning blade 2, and FIG. 28B is an enlarged view of a region C in FIG. If the front edge line 21 has an obtuse angle, even if the front edge line 21 is pulled in the direction of the arrow D by the frictional force with the photoreceptor 1, it is less likely to be deformed than when it is a right angle, and the front edge line 21 is shown in FIG. The turn up is small. When the turning is reduced, the contact length in the direction of arrow D between the cleaning blade 2 and the surface of the photoreceptor 1 is shortened, and the contact area between the cleaning blade 2 and the surface of the photoreceptor 1 is also narrowed. If the area where the cleaning blade 2 and the surface of the photoconductor 1 are in contact with each other is small, the tip ridge line portion 21 has a right angle even when the same load is applied from the cleaning blade 2 to the photoconductor 1 as the tip ridge line portion 21 has a right angle. The surface pressure is higher than in the case of. By increasing the surface pressure according to the shape of the blade tip, it is possible to efficiently prevent the toner from slipping through the contact portion with respect to the load applied to the photoreceptor 1, and to prevent the occurrence of defective cleaning. .

  Moreover, when making the front-end | tip angle of the cleaning blade 2 an obtuse angle, the range of 95 [°] to 140 [°] is preferable. When the tip angle is very close to 90 [°], the reduction of the contact area due to the obtuse angle is not exhibited. The cleaning blade 2 is installed in an apparatus with an initial contact angle of 15 [°] to 30 [°]. Therefore, when the tip angle is 140 [°] and the initial contact angle is 30 [°], the angle formed by the blade tip surface and the surface of the photoreceptor 1 is 10 [°]. When this angle becomes a small value, toner accumulates in a wedge-shaped gap between the blade end and the photoreceptor 1, and the contact area between the cleaning blade 2 and the photoreceptor 1 is substantially increased. As a result, the surface pressure decreases, and as a result, a cleaning failure may occur.

  In the printer 200, the elastic member used for the cleaning blade 2 has a rebound resilience (rebound resilience coefficient JIS-K-6255) at a temperature of 23 [° C.] of 30% or less. There are two reasons for using such a cleaning blade 2. The first reason is that it is better to have less vibration at the tip of the cleaning blade in order to clean the spherical toner satisfactorily. The second reason is that it is better that the resilience modulus is lower with respect to the abrasion of the cleaning blade 2. Therefore, in the printer 200, it is possible to suppress deterioration of the cleaning property due to vibration of the blade tip while suppressing wear of the cleaning blade 2.

  Conventionally, when cleaning the pulverized toner, the cleaning blade 2 has the effect of causing the toner contacting the blade tip to jump off, so that when the rebound resilience is low, the splash-off effect does not work sufficiently. was there. However, in the case of spherical toner, since the cleaning blade 2 passes through before the toner is bounced back, the bounce-off effect does not work. On the contrary, it has been found that if the impact resilience is high and the blade tip tends to vibrate slightly with respect to the photosensitive member, the spherical toner is promoted.

  On the other hand, it has been found that a lower impact resilience is advantageous for the abrasion of the cleaning blade 2. That is, in the repeated image forming process, the cleaning blade 2 gradually wears due to the rubbing with the photoreceptor 1. We consider that the mechanism of wear of the cleaning blade 2 is that wear occurs as a result of tearing of the polymer (for example, polyurethane rubber) constituting the blade as a result of the stick-slip motion of the cleaning blade 2 itself and fatigue failure. Yes. In such a case, the tip of the cleaning blade 2 is torn off and a defective cleaning occurs therefrom. On the other hand, when the rebound resilience is lowered, the stick-slip motion of the blade itself is suppressed. Fatigue fracture is also suppressed because it is small. As a result, the cleaning blade wear does not proceed even after repeated image forming steps, and the cleaning performance is maintained for a long time.

  As described above, when the contact pressure necessary for cleaning the spherical toner is obtained, the contact pressure must be higher than that of the pulverized toner. When the contact pressure is increased in this manner, the surface of the photoreceptor 1 is naturally easily worn.

  Therefore, in this printer, a photoconductor 1 that is a negatively chargeable organic photoconductor is provided with a special surface protective layer. FIG. 23 is a schematic diagram showing the photosensitive member 1 of the printer 200. In FIG. 23, the photosensitive member 1 is obtained by providing a photosensitive layer or the like on a drum-shaped conductive support having a diameter of 30 [mm].

  An undercoat layer 1d, which is an insulating layer, is provided on the conductive support 1e as a base layer. Further, a charge generation layer (CGL) 1c and a charge transport layer (CTL) 1b are provided as photosensitive layers. Furthermore, a surface protective layer (FR) 1a is laminated thereon.

  As the conductive support, a conductive support having a volume resistance of 1010 Ω · cm or less can be used. For example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, or a metal oxide such as tin oxide or indium oxide is coated on a film or cylindrical plastic or paper by vapor deposition or sputtering. There is something. Alternatively, a plate made of aluminum, aluminum alloy, nickel, stainless steel, or the like, and a tube subjected to surface treatment such as cutting, superfinishing, polishing, or the like after forming the raw tube by a method such as extrusion or drawing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

  In addition to this, the conductive support dispersed in a conductive binder dispersed in a suitable binder resin can also be used as the conductive support 1e. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

  The charge generation layer is a layer mainly composed of a charge generation material. Known charge generation materials can be used for the charge generation layer, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, Squalic acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, azulenium salt dyes and the like can be mentioned, and these are usefully used. These charge generation materials can be used alone or in combination.

  In the charge generation layer, the charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is dispersed on the conductive support or the undercoat layer. It is formed by coating on top and drying.

  In the charge generation layer, the charge generation material can be dispersed in the binder resin as necessary. Examples of binder resins that can be used include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, poly Examples include acrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight, per 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.

  Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. In particular, ketone solvents, ester solvents, and ether solvents are preferably used. These may be used alone or in combination of two or more.

  The charge generation layer is mainly composed of a charge generation material, a solvent, and a binder resin, and may contain any additive such as a sensitizer, a dispersant, a surfactant, and silicone oil. good.

  As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.

  The thickness of the charge generation layer is suitably about 0.01 to 5 [μm], preferably 0.1 to 2 [μm].

  The charge transport layer can be formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer. If necessary, one or more plasticizers, leveling agents, antioxidants and the like can be added.

  Charge transport materials include hole transport materials and electron transport materials. Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

  Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. Other known materials may be used. These charge transport materials may be used alone or in combination of two or more.

  As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic or thermosetting resins such as phenol resins and alkyd resins.

  The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably 25 [μm] or less from the viewpoint of resolution and responsiveness. Regarding the lower limit, although it differs depending on the system to be used (particularly charging potential, etc.), 5 [μm] or more is preferable.

  As the solvent, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone or the like is used. These may be used alone or in combination of two or more.

  The photosensitive layer is formed by dissolving or dispersing the above-described charge generation material, charge transport material, binder resin, etc. in an appropriate solvent, and applying and drying the solution on the conductive support 1e or the undercoat layer 1d. it can. You may comprise from a charge generation material and binder resin, without containing a charge transport material. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight.

  The photosensitive layer is formed by dip coating, spray coating, bead coating, a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transporting material using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a ring coat or the like. The film thickness of the photosensitive layer is suitably about 5 to 25 [μm].

  The undercoat layer 1d is generally composed of a resin as a main component. However, considering that the photosensitive layer is applied with a solvent thereon, these resins are resins having a high solvent resistance with respect to a general organic solvent. Is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. A metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential. Further, these undercoat layers can be formed using an appropriate solvent and coating method as in the above-described photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention.

  In addition, for the undercoat layer 1d, a vacuum thin film forming method may be used in which Al2O3 is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), and inorganic substances such as SiO2, SnO2, TiO2, ITO, CeO2 are used. Can be used well. In addition, known ones can be used. The film thickness of the undercoat layer 1d is suitably from 0 to 5 [μm].

  As the surface protective layer 1a, for example, a surface coated with amorphous silicon to improve wear resistance, or a surface in which alumina, tin oxide or the like is dispersed on the surface of the charge transport layer can be employed.

  The configuration of the photoreceptor 1 is not limited to the configuration described so far. A one-layer structure in which only a photosensitive layer mainly composed of a charge generation material and a charge transport material is provided on the conductive support 1e may be used. Alternatively, a structure in which a charge generation layer mainly composed of a charge generation material and a charge transport layer mainly composed of a charge transport material are laminated on a conductive support may be employed. A photosensitive layer mainly composed of a charge generation material and a charge transport material is provided on the conductive support. Then, a structure in which a protective layer is further provided thereon, a charge generation layer mainly composed of a charge generation material and a charge transport layer mainly composed of a charge transport material are laminated on a conductive support, The structure which provided the protective layer on the electric charge transport layer may be sufficient. Also, a structure in which a charge transport layer mainly composed of a charge transport material and a charge generation layer mainly composed of a charge generation material are laminated on a conductive support, and a protective layer is provided on the charge generation layer. But you can.

  A cross-linked structure is used as the binder structure of the surface protective layer 1a. Regarding the formation of the cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used, and a cross-linking reaction is caused using light or heat energy to form a three-dimensional network structure. This network structure functions as a binder resin and exhibits high wear resistance.

  From the viewpoint of electrical stability, printing durability, and life, it is very effective to use a monomer having charge transporting ability in whole or in part as the reactive monomer. By using such a monomer, a charge transporting site is formed in the network structure, and the function as a protective layer can be sufficiently expressed.

  Examples of the reactive monomer having charge transporting ability include a compound containing at least one charge transporting component and at least one silicon atom having a hydrolyzable substituent in the same molecule. There are also compounds containing a charge transporting component and a hydroxyl group in the same molecule, and compounds containing a charge transporting component and a carboxyl group in the same molecule. Furthermore, a compound containing a charge transporting component and an epoxy group in the same molecule, a compound containing a charge transporting component and an isocyanate group in the same molecule, and the like can be mentioned. These charge transport materials having a reactive group may be used alone or in combination of two or more. More preferably, a reactive monomer having a triarylamine structure is effectively used as the monomer having a charge transporting ability because of high electrical and chemical stability and high carrier mobility.

  In addition to this, monofunctional and bifunctional polymerizable monomers and polymerizable oligomers are used in combination for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, low surface energy and friction coefficient reduction. be able to. As these polymerizable monomers and oligomers, known ones can be used.

  The hole transporting compound is polymerized or cross-linked using heat or light, but when the polymerization reaction is performed by heat, the polymerization reaction may proceed only with thermal energy or a polymerization initiator may be required. . In order to efficiently advance the reaction at a lower temperature, it is preferable to add an initiator.

  In the case of polymerization by light, it is preferable to use ultraviolet light as light, but the reaction rarely proceeds only by light energy, and a photopolymerization initiator is generally used in combination. The polymerization initiator in this case mainly absorbs ultraviolet rays having a wavelength of 400 nm or less, generates active species such as radicals and ions, and initiates polymerization. In the present invention, the above-described heat and photopolymerization initiator can be used in combination.

  The charge transport layer having a network structure formed in this manner has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and if it is too thick, it may cause cracks. In such a case, the protective layer may be a laminated structure, a low molecular dispersion polymer protective layer may be used for the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure may be formed on the upper layer (surface side). good.

  The photoconductor provided with the surface protective layer as described above is manufactured in the same manner as a well-known method except that the protective layer coating solution, film thickness, and preparation conditions are devised as described below. can do. That is, first, 182 parts by weight of methyltrimethoxysilane, 40 parts by weight of dihydroxymethyltriphenylamine, 225 parts by weight of 2-propanol, 106 parts by weight of 2% acetic acid, and 1 part by weight of aluminum trisacetylacetonate are mixed to protect the surface. A coating solution for the layer is obtained. This coating solution is applied onto the charge transport layer and dried, and then heat-cured for 1 hour in an environment of 110 [° C.] to form a surface protective layer having a thickness of 3 [μm].

Further, for example, a well-known method may be used except that the protective layer coating solution, film thickness, and preparation conditions are devised as described below. That is, 30 parts by weight of a hole transporting compound having a chemical structural formula shown in Chemical Formula 1, and an acrylic monomer having a chemical structural formula shown in Chemical Formula 2 and a photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone). 0.6 parts by weight of the mixture is dissolved in a mixed solvent of 50 parts by weight of monochlorobenzene / 50 parts by weight of dichloromethane to obtain a coating material for the surface protective layer. This paint is applied on the charge transport layer by spray coating, and cured for 30 seconds with a light intensity of 500 [mW / cm 2] using a metal halide lamp to form a surface protective layer having a thickness of 5 μm.

  In the printer 200 described so far, a toner having an average circularity of 0.98 or more and a volume average particle diameter of 5 [μm] is used as a toner by polymerization. The average circularity can be measured using a flow type particle image analyzer FPIA-2000 (trade name, manufactured by Toa Medical Electronics Co., Ltd.). Specifically, in 100 to 150 [ml] of water from which impure solids have been removed in advance in a container, a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, 0.1 to 0.5 [ml], Further, about 0.1 to 0.5 [g] of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes so that the dispersion concentration becomes 3000 to 1 [10,000 / μl]. Set and measure toner shape and distribution. Based on this measurement result, the outer peripheral length of the toner projection shape is L1 (FIG. 24), the projected area is S, and the outer circumference of the same circle as the projected area S is L2 (FIG. 25). / L1 is obtained and the average value is defined as the circularity.

  The volume average particle diameter can be determined by a Coulter counter method. Specifically, the toner number distribution and volume distribution data measured by the Coulter Multisizer 2e type (manufactured by Coulter) are sent to a personal computer via an interface (manufactured by Nikkaki Co., Ltd.) for analysis. More specifically, a 1% NaCl aqueous solution using first grade sodium chloride is prepared as an electrolytic solution. Then, 0.1 to 5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Further, 2 to 20 [mg] of toner as a test sample is added thereto, and the dispersion treatment is performed for about 1 to 3 minutes using an ultrasonic disperser. Then, 100 to 200 [ml] of the electrolytic aqueous solution is put into another beaker, and the solution after the dispersion treatment is added to the beaker so as to have a predetermined concentration, and applied to the Coulter Multisizer 2e type. The aperture is 100 [μm], and the particle size of 50,000 toner particles is measured. As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], toner particles having a particle size of 2.00 [μm] or more and 32.0 [μm] or less are targeted. Then, the volume average particle diameter is calculated based on the relational expression “volume average particle diameter = ΣXfV / ΣfV”. However, X is the representative diameter in each channel, V is the equivalent volume in the representative diameter of each channel, and f is the number of particles in each channel.

  As the pulverization method further develops in the future, it may be possible to obtain a toner having a very high average circularity even by the pulverization method. In such a case, even with toner by the pulverization method, cleaning defects are likely to occur as in the case of toner by the polymerization method.

  As shown in FIG. 26, the toner used in each experiment described above (average circularity of 0.98 or more and volume average particle size of 5 μm) has a particle size of 2.5 to 7.0 [μm] in the range of 95 [ %] Toner particles are present. This distribution state is the same for the untransferred toner (toner that is actually cleaned).

  Although an example in which the present invention is applied to the process unit 100 has been described, the present invention can also be applied to an image forming apparatus in which the cleaning unit is not configured as a process unit.

As described above, according to this embodiment, a plurality of protective agent supply units are provided, and the protective agent is supplied to a plurality of locations in the surface movement direction of the photoreceptor 1, thereby achieving uniform supply amount in the axial direction.
In addition, a plurality of protective agent supply means are provided at specific locations to achieve both suppression of deterioration due to proximity discharge and suppression of increase in the amount of toner passing through the cleaning blade due to the deteriorated protective agent. By supplying the protective agent to the first supply region 150 downstream of the cleaning blade 2 and upstream of the charging device 110 by the first protective agent supply means 151, the first protective agent supply means 151 passes through the discharge region with a uniform protective layer formed. Let Therefore, it is possible to effectively prevent the surface of the photoreceptor 1 from being deteriorated due to the proximity discharge. Further, by supplying the protective agent to the second supply region 160 downstream of the charging device 110 and upstream of the cleaning blade by the second protective agent supply means 162, the protective agent deteriorated when passing through the cleaning blade is directly applied to the cleaning blade. Make it difficult to touch. Thus, by supplying the protective agent to the first supply region 150 by the first protective agent supply means 151 and the second supply region 160 by the second protective agent supply means 161, suppression of deterioration due to proximity discharge, and It is possible to simultaneously suppress an increase in the amount of toner passing through the cleaning blade due to the deteriorated protective agent.
In addition, a rotatable fur brush 152 disposed so as to contact the first supply region 150 as the first protective agent supply unit 151 and a solid protective agent 153 that contacts the fur brush 152 include a second protective agent supply unit 161. And a rotatable fur brush 162 disposed so as to contact the second supply region 160 and a solid protective agent 163 contacting the fur brush 162, respectively. Thus, the protective agent scraped off by the fur brush 152 and the fur brush 162 is applied to the photoconductor 1, whereby the protective agent can be supplied to the first supply region 150 and the second supply region 160.
The second protective agent supply means 161 includes a rotatable fur brush 161 that contacts the surface of the intermediate transfer body 45 and a solid protective agent 163 that contacts the fur brush 161, and the protective agent scraped off by the fur brush 161 is used. It is applied to the intermediate transfer body 45, and the protective agent is supplied to the second supply region 160 of the photoreceptor via the intermediate transfer body 45. Thereby, the space around the photosensitive member can be saved. Further, in a printer having a plurality of photoconductors, the second protective agent is not provided with a plurality of second protective agent supply means so as to face each photoconductor, but opposed to the intermediate transfer member 45 facing each photoconductor. Only one supply means can be provided, and the protective agent can be supplied to the second supply regions of the plurality of photoconductors. Therefore, the number of parts can be reduced.
Further, by using toner containing a protective agent as the second protective agent supply means 161, it is not necessary to provide a separate device, and the space of the device can be reduced and the cost can be reduced.
In addition, by setting the angle of the edge portion of the cleaning blade 2 to 95 ° or more and 140 ° or less, it is possible to efficiently prevent the toner from slipping through the contact portion with respect to the load applied to the photoreceptor 1. The occurrence of defective cleaning can be prevented.
Further, by using a toner having an average circularity of 0.98 or more,
In the printer 200, a toner having an average circularity of 0.98 or more can be used as a toner, so that a higher resolution image can be formed. By using the cleaning blade 2 for cleaning the toner, it is possible to satisfactorily clean the toner that is difficult to remove.
Further, by providing the photoreceptor 1 with a surface protective layer made of a material containing fine particles made of an inorganic compound, the abrasion resistance of the photoreceptor 1 can be improved.
Further, by providing the photoreceptor 1 with a surface protective layer made of a binder resin having a crosslinked structure, the abrasion resistance of the photoreceptor 1 can be improved.
Furthermore, the electrical stability of the photoreceptor 1 can be improved by providing a charge transport layer in the structure of the binder resin.
The process unit 100 having the photosensitive member 1, the charging roller 111, the cleaning blade 2, the first protective agent supply unit 151, and the second protective agent supply unit 161 is attached to and detached from the main body of the printer 200 as an image forming apparatus. It is possible. As a result, the surface of the image carrier caused by the proximity discharge is prevented from being deteriorated, and the protective agent supplied to the surface of the image carrier is deteriorated by the proximity discharge, adversely affecting the cleaning blade and increasing the amount of toner passing through. It is possible to provide a process unit 100 that can suppress the above. Furthermore, by configuring the process unit 100, maintenance such as replacement, repair, and replenishment can be facilitated, and the size of the printer 200 main body can be reduced.

1 is a schematic configuration diagram of a printer according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating a process unit in the printer. FIG. 2 is a schematic configuration diagram illustrating a charging device in the process unit together with a photoreceptor. The perspective view of the printer provided with two or more protective agent supply means of this embodiment. FIG. 2 is a schematic configuration diagram of a printer provided with a protective agent supply unit of the present embodiment in a plurality of specific areas. The schematic block diagram of the printer provided with the protective agent supply means which provided the powdery protective agent retention area | region. FIG. 4 is a schematic configuration diagram of a printer including a second protective agent supply unit via an intermediate transfer member. FIG. 6 is a schematic configuration diagram of another example of a printer including a second protective agent supply unit via an intermediate transfer member. FIG. 3 is a schematic configuration diagram of a printer including a second protective agent supply unit using toner containing a protective agent. Explanatory drawing of the experimental method of the conditions 1 in Table 1. FIG. Explanatory drawing of the experimental method of the conditions 2 in Table 1. FIG. (A) is when zinc stearate is applied. (B) shows the amount of toner passing through. Explanatory drawing of the experimental method of the conditions 3 in Table 1. FIG. (A) is when zinc stearate is applied. (B) shows the amount of slipping toner. Explanatory drawing of the experimental method of the conditions 4 in Table 1. FIG. (A) is when zinc stearate is applied. (B) shows the amount of toner passing through. The graph which shows the experimental result of conditions 1-5 of Table 1. FIG. Schematic which shows the conventional holder and a cleaning blade. FIG. 3 is an enlarged view showing a tip portion of a conventional cleaning blade pressed against a photoconductor with a strong pressing force capable of satisfactorily cleaning toner by a polymerization method. FIG. 17 is a pressure distribution diagram at the tip of the cleaning blade in the state shown in FIG. 16. Schematic explanatory drawing which shows the cleaning blade and holder which have a thick part. The enlarged view which shows the front-end | tip part of the cleaning blade. The pressure distribution diagram of the cleaning blade. Explanatory drawing of the blade shape whose front-end ridgeline part of a cleaning blade is a right angle. Explanatory drawing of the blade shape whose front-end ridgeline part of a cleaning blade is an obtuse angle. FIG. 2 is a schematic diagram showing a cross section of a photoreceptor. FIG. 6 is a schematic diagram illustrating an outer peripheral length of a projected image of toner. FIG. 6 is a schematic diagram for explaining the outer peripheral length of a perfect circle having the same projection area as that of toner. The graph which shows the particle size distribution of a toner. Explanatory drawing of the cleaning blade whose front-end ridgeline part is a right angle. (A) is an overall view of the blade, (b) is an enlarged view of the vicinity of the tip. Explanatory drawing of the cleaning blade whose front-end ridgeline part is an obtuse angle. (A) is an overall view of the blade, (b) is an enlarged view of the vicinity of the tip. FIG. 6 is a schematic configuration diagram of a printer including a conventional protective agent supply unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Cleaning blade 2a Thick part 10 Paper feed cassette 20 Conveying roller pair 21 Front edge line part 22 Blade front end surface 23 Blade lower surface 24 Blade upper surface 25 Gap 30 Recording material conveyance path 31 Registration roller pair 40 Transfer device 41 Conveyance belt 42 Conveyor belt driving roller 43 Recording member transfer bias roller 44 Conveyor belt cleaning device 44a Fur brush 45 Intermediate transfer member 46 Secondary transfer roller
DESCRIPTION OF SYMBOLS 50 Fixing device 60 Paper discharge roller pair 100 Process unit 101 Optical writing unit 110 Charging device 111 Charging roller 111a Shaft portion 111b Roller portion 112 Spacer 115 Spring 118 Supply conveyance screw 119 Developer supply portion 120 Developing device 121 Developing casing 122 Developing portion 123 Developer Stirrer 124 Developer Sleeve 125 Doctor Blade 126 Magnet Roller 127 Stir Transport Screw 128 T Sensor 129 Partition Wall 130 Photoconductor Cleaning Device 131 Photoconductor Removal Casing 132 Holder 134 Recovery Screw 135 Protective Agent Supply Unit 135A, B Protective Agent Supply Means 136 Fur brush 136A, B Fur brush 137 Solid protective agent 137A, B Solid protective agent 138 Pressure spring 140 Static eliminator 150 First Supply area 151 First protective agent supply means 152 Fur brush 153 Solid protective agent 154 Pressure spring 155 First protective agent retention area 156 Partition member 157 Powder protective agent 160 Second supply area 161 Second protective agent supply means 162 Fur brush 163 Solid protective agent 164 Pressure spring 165 First protective agent retention region 166 Partition member 167 Powder protective agent 170 Stretching blade 200 Printer P Transfer paper

Claims (13)

An image carrier that carries an electrostatic latent image, a charging device that charges the surface of the image carrier by a proximity discharge from a charging member disposed in proximity to the image carrier, and a latent image on the image carrier is developed. An image forming apparatus comprising: a developing device for cleaning; and a cleaning device having a cleaning blade for removing toner remaining on the image carrier after the developed toner image is transferred to a transfer material.
An image forming apparatus comprising a plurality of protective agent supplying means for applying a protective agent for protecting the surface of the image carrier at a plurality of locations in the surface movement direction of the image carrier. An image carrier that carries an electrostatic latent image, a charging device that charges the surface of the image carrier by a proximity discharge from a charging member disposed in proximity to the image carrier, and a latent image on the image carrier is developed. An image forming apparatus comprising: a developing device for cleaning; and a cleaning device having a cleaning blade for removing toner remaining on the image carrier after the developed toner image is transferred to a transfer material.
A first protective agent supply means for supplying the protective agent to a first supply region downstream of the cleaning blade and upstream of the charging device with respect to the surface movement direction of the image carrier; and downstream of the charging device An image forming apparatus comprising: a second protective agent supply unit that supplies the protective agent to a second supply region upstream of the cleaning blade.   The image forming apparatus according to claim 2, wherein the first protective agent supply means is a rotatable supply member arranged to contact the first supply region of the image carrier, and a solid protective agent that contacts the supply member. Respectively, a rotatable supply member disposed so as to contact the second supply region of the image carrier, and a solid protective agent contacting the supply member. An image forming apparatus characterized by supplying the protective agent to the first supply region and the second supply region, respectively, by applying the protective agent scraped off in step (b) to the image carrier. .   3. The image forming apparatus according to claim 2, wherein an intermediate transfer body that contacts the image carrier and transfers a toner image formed on the image carrier is provided, and the second protective agent supply means is provided on the surface of the intermediate transfer body. A rotatable supply member that is in contact; and a solid protective agent that is in contact with the supply member, the protective agent scraped off by the supply member is applied to the intermediate transfer member, and the protective agent is interposed via the intermediate transfer member. Is supplied to the second supply region of the image carrier.   5. The image forming apparatus according to claim 4, wherein the first protective agent supply means is disposed so as to contact the first supply region on the surface of the image carrier, and the solid protective agent is in contact with the supply member. An image forming apparatus, wherein the protective agent scraped off by the supply member is supplied to a first supply region of the image carrier.   3. The image forming apparatus according to claim 2, wherein the second protective agent supply means develops the latent image on the image carrier using a toner containing a protective agent, thereby developing the protective agent on the image carrier. An image forming apparatus that supplies to two supply areas.   7. The image forming apparatus according to claim 6, wherein the first protective agent supply means is disposed so as to contact the first supply region on the surface of the image carrier, and the solid protective agent is in contact with the supply member. An image forming apparatus, wherein the protective agent scraped off by the supply member is supplied to a first supply region of the image carrier.   8. The image forming apparatus according to claim 1, wherein an angle of a tip ridge line portion of the cleaning blade is 95 ° or more and 140 ° or less.   9. The image forming apparatus according to claim 1, wherein the toner has an average circularity of 0.98 or more.   10. The image forming apparatus according to claim 1, wherein the image carrier has a surface protective layer made of a material containing fine particles made of an inorganic compound. An image forming apparatus used.   11. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the image carrier has a surface protective layer made of a binder resin having a crosslinked structure. An image forming apparatus.   12. The image forming apparatus according to claim 11, further comprising a charge transport layer in a structure of the surface protective layer. An image forming apparatus main body integrally formed with an image carrier, a charging device, a cleaning device, and a protective agent supplying means for supplying a protective agent to the surface of the image carrier to protect the surface of the image carrier In a process unit that can be attached to and detached from
The first protective agent supply means and the second protective agent supply described in the image forming apparatus according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 as the protective agent supply means. A process unit characterized by adopting means.

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