JP5234398B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

  Conventionally, as a cleaning means for removing transfer residual toner remaining on a photoconductor after a toner image has been transferred, a blade cleaning system that mechanically removes transfer residual toner by bringing a rubber blade into contact with the photoconductor It has been known. In the blade cleaning method, if the accuracy of close contact between the blade and the surface of the photoconductor is low, the transfer residual toner slips through and the cleaning performance is likely to deteriorate. In order to prevent this, the blade is pressed against the photosensitive member with a strong contact pressure. However, when the blade is pressed against the photosensitive member with a strong contact pressure, the blade is turned over, causing streaky or strip-like cleaning failure, and it is difficult to maintain stable cleaning performance. Further, in the long term, the surface film scraping of the photoreceptor is promoted and the life of the photoreceptor is shortened.

  In recent years, there has been an increasing demand for higher image quality, and there is a tendency to reduce the particle size of toner. Further, in order to reduce the toner manufacturing cost and improve the transfer rate, an image forming apparatus that employs a spherical toner obtained by polymerization from a pulverized (indeterminate) toner has been commercialized. When such a small particle diameter and spherical toner is used, it is known that the cleaning property is inferior to the pulverized toner in the blade cleaning method.

  Patent Documents 1 to 3 describe a cleaning method that has good cleaning properties when cleaning small-diameter toner and spherical toner and that suppresses mechanical rubbing that can reduce surface film abrasion of the photoreceptor. There is an electrostatic cleaning method in which the transfer residual toner on the surface of the image carrier is cleaned by electrostatic action.

  The transfer residual toner on the surface of the photoconductor after transfer has a charge. For this reason, the electrostatic cleaning type cleaning device applies the voltage opposite to the charged polarity of the toner to the electrostatic cleaning member and transfers it to the electrostatic cleaning member by utilizing the property of the transfer residual toner having a charge. The residual toner is electrostatically adsorbed to remove the residual transfer toner from the surface of the image carrier.

JP 2005-265907 A JP 2006-154307 A JP 2003-280251 A

  However, in the above-described electrostatic cleaning method, there is a problem in that the image is soiled when the interval until the next image forming operation is long.

  Thus, the present inventors conducted extensive research on the above problems and found the following. That is, when the transfer of the toner image on the photoconductor is completed, the image forming operation is terminated and the rotation of the image carrier is stopped. At this time, the transfer residual toner on the image carrier that has not passed through the contact position with the electrostatic cleaning member remains on the surface of the image carrier until the next image forming operation. However, if the interval until the next image forming operation is long, the transfer residual toner on the image carrier loses charged charges due to natural discharge. As described above, the untransferred toner on the image carrier that has lost the charged electric charge passes without electrostatically adhering to the electrostatic cleaning member at the contact position with the electrostatic cleaning member during the next image forming operation. . As a result, it has been found that there is a problem that background stains occur in the formed image.

  The present invention has been made in view of the above problems, and the object of the present invention is to form a formed image even if the interval from the end of an image forming operation to the start of the next image forming operation is increased. An object of the present invention is to provide an image forming apparatus capable of suppressing the occurrence of background stains.

To achieve the above object, the invention of claim 1 comprises an image carrier, charging means for charging the image carrier, exposure means for exposing the image carrier to form an electrostatic latent image, and Developing means for converting the electrostatic latent image on the image carrier into a toner image, transfer means for transferring the toner image on the image carrier to a transfer material, and transfer residual toner on the image carrier electrostatically An electrostatic cleaning member having a movable surface that is moved to and removed from the surface of the image bearing member and disposed on the upstream side of the surface of the image bearing member relative to the electrostatic cleaning member. A polarity control member for controlling the charging polarity of the transfer residual toner on the carrier, a recovery member for electrostatically moving the toner adhering to the surface of the electrostatic cleaning member to its surface, and a recovery member; Abutted and adhered to the surface of the recovery member Removing the toner, and a recovery member for a cleaning blade to impart toner charging polarity opposite to the polarity of the charge that adheres to the collecting member surface to the surface of the collecting member, after completion of the image forming operation, the image bearing member surface And a control unit that executes a cleaning mode for removing transfer residual toner between the polarity control member and the electrostatic cleaning member in the moving direction.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the electrostatic cleaning member has a two-layered core-sheath brush in which the inside is made of a conductive material and the surface portion is made of an insulating material. A cleaning brush provided with fibers, wherein the brush fibers are inclined to the downstream side of the cleaning brush surface movement direction with respect to the normal direction of the peripheral surface of the metal core of the cleaning brush.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the voltage for applying a voltage having a polarity opposite to the charged polarity of the residual toner controlled by the polarity control member to the electrostatic cleaning member. An application means is provided.
Further, the invention of claim 4, in any of the image forming apparatus according to claim 1 to 3, prior to the transfer residual toner on the Kizo bearing member is recovered by the recovery member, so as to perform the cleaning mode the The control means is configured.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, a toner having a shape factor SF1 of 100 to 150 is used as the toner.
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, an image carrier in which filler is dispersed is used as the image carrier.
According to a seventh aspect of the present invention, there is provided the image forming apparatus according to any one of the first to sixth aspects, wherein the image bearing member is an organic photoreceptor having a surface layer reinforced with a filler, or a cross-linked charge transporting material. It is characterized by using an organic photoreceptor using
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the image carrier and at least one of the charging unit, the developing unit, and the electrostatic cleaning member are integrated. The process cartridge is supported and detachable from the apparatus main body.

According to the present invention , after the image forming operation is completed, the cleaning mode is executed to remove the transfer residual toner between the polarity control member and the electrostatic cleaning member. Therefore, during the next image forming operation, the polarity control member removes the transfer residual toner. It is possible to suppress the transfer residual toner from remaining before the electrostatic cleaning member . Therefore, even if the interval until the next image forming operation becomes long, there is almost no residual transfer toner from which the charged charge is lost between the polarity control member and the electrostatic cleaning member. The transfer residual toner that passes without electrostatically adhering to the cleaning member can be almost eliminated. Thereby, even if the interval from the end of the image forming operation to the start of the next image forming operation becomes longer, it is possible to suppress the occurrence of background stains on the formed image.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic printer (hereinafter simply referred to as a printer 100) as an image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram illustrating a main part of the printer according to the present embodiment. The printer 100 performs single-color copying, and forms a monochrome image based on image data read by an image reading unit (not shown).

  First, the overall configuration of the printer 100 will be described. As shown in FIG. 1, the printer 100 includes a drum-shaped photoconductor 1 as an image carrier. Around the photoreceptor 1, a charging roller 3 as a charging unit, a developing device 6 as a developing unit that converts a latent image into a toner image, a transfer roller 15 as a transfer unit that transfers a toner image onto a transfer sheet as a recording medium, A cleaning device 20 for cleaning the toner remaining on the photoconductor 1 after the transfer, a static elimination lamp 2 for neutralizing the photoconductor 1 and the like are disposed. Further, a light shielding plate 40 that shields the light from the static elimination lamp is provided between the static elimination lamp 2 and the charging roller 3.

  The charging roller 3 is arranged in a non-contact manner with a predetermined distance from the photoconductor 1, and charges the photoconductor 1 to a predetermined polarity and a predetermined potential. In the printer 100, the photosensitive member 1 is uniformly charged to a negative polarity. The photoreceptor 1 uniformly charged by the charging roller 3 is irradiated with laser light 4 from an exposure device (not shown) as an exposure unit based on image data, and an electrostatic latent image is formed.

  The developing device 6 has a developing roller 8 as a developer carrying member including a magnet as magnetic field generating means. A developing bias is applied to the developing roller 8 from a power source (not shown). In the casing 7 of the developing device 6, a supply screw 9 and a stirring screw 10 are provided for stirring the two-component developer composed of toner and carrier contained in the casing 7 while transporting them in opposite directions. A doctor 5 for regulating the developer carried on the developing roller 8 is also provided. The toner in the developer stirred and conveyed by the two screws of the supply screw 9 and the stirring screw 10 is charged to a negative polarity. The developer is pumped up to the developing roller 8 by the action of a magnet included in the developing roller 8. The developer thus pumped up is regulated by the doctor 5, and in a developing region facing the photoreceptor 1, the developer is brought up by a magnetic force of a magnet to form a magnetic brush.

  Further, a transfer bias is applied to the transfer roller 15 from a power source (not shown).

  Further, the cleaning device 20 is provided with a cleaning brush 23 as an electrostatic cleaning member, which will be described later in detail, and electrostatically removes transfer residual toner on the photoreceptor 1.

Next, an image forming operation in the printer 100 will be described.
In the printer 100, when a copy start button of an operation unit (not shown) is pressed, reading of a document is started by an image reading unit (not shown). A predetermined voltage or current is sequentially applied to the charging roller 3, the developing roller 8, the transfer roller 15, and the cleaning brush 23 at predetermined timings. In synchronism with this, the photosensitive member 1 is rotationally driven in the direction of arrow A in the figure by a photosensitive member driving motor (not shown) as driving means. Simultaneously with the rotation of the photosensitive member 1, the developing roller 8, the transfer roller 15, the supply screw 9, the stirring screw 10, and a toner discharge screw 19, a cleaning brush 23, and a collection roller 24, which will be described in detail later, are also rotated in a predetermined direction. The

  When the photoconductor 1 rotates in the direction of arrow A in the figure, the photoconductor 1 is first charged to a potential of, for example, −700 [V] by the charging roller 3. Then, a laser beam 4 corresponding to the image signal is irradiated to the photosensitive member 1 from an exposure device (not shown), and the potential of the photosensitive member 1 in the portion irradiated with the laser beam 4 is lowered to, for example, −120 [V], and the electrostatic latent An image is formed.

  The photoreceptor 1 on which the electrostatic latent image is formed is rubbed on the surface of the photoreceptor 1 with a magnetic brush of developer formed on the developing roller 8 at a portion facing the developing device 6. At this time, the negatively charged toner on the developing roller 8 is moved to the electrostatic latent image side by a developing bias of, for example, −450 [V] applied to the developing roller 8, and is formed into a toner image (development). As described above, in this embodiment, the electrostatic latent image formed on the photosensitive member 1 is reversed by the toner charged to the negative polarity by the developing device 6 (negative positive (N / P): toner at a low potential. Develop using development.

The toner image formed on the photosensitive member 1 is guided by guide plates 13 and 14 from a sheet feeding unit (not shown) through an opposing portion of the upper registration roller 11 and the lower registration roller 12, and the photosensitive member 1 and the transfer roller 15. Are transferred to a transfer sheet fed to a transfer area formed between the two. At this time, the transfer paper is supplied in synchronism with the leading edge of the image at a portion where the upper registration roller 11 and the lower registration roller 12 face each other. Further, at the time of transfer to transfer paper, a transfer bias whose constant current is controlled to, for example, +10 [μA] is applied to the transfer roller 15. The transfer paper onto which the toner image has been transferred is separated from the photoreceptor 1 by a separation claw 16 as a separation unit, guided by a conveyance guide plate 41, and conveyed to a fixing device as a fixing unit (not shown). By passing through the fixing device, the toner image is fixed on the transfer paper by the action of heat and pressure, and the transfer paper is discharged out of the apparatus.
On the other hand, after the transfer, the transfer residual toner is removed by the cleaning device 20 and the charge is removed by the charge removal lamp 2.

  Next, the cleaning device 20 that removes the transfer residual toner on the photoreceptor 1 will be described.

First, a conventional blade cleaning type cleaning device will be described.
An image forming apparatus is required to have a high resolution so that a higher-precision and higher-definition image can be formed. One means for achieving this is to use a toner having a smaller particle size. Further, in order to improve the transfer rate, the shape of toner is changed from an indefinite shape to a shape closer to a sphere. However, in the conventional blade cleaning method, it is difficult to clean the toner having a small particle size or a spherical shape.
Further, even with the blade cleaning method, if the linear pressure is extremely increased (specifically, linear pressure: 100 [gf / cm] or more), it is possible to clean toner having a small particle size or spheroidization. The lifetime of the minute photoconductor and the cleaning blade is extremely shortened. Photoconductor life at normal linear pressure (20 [gf / cm]) (life when the photosensitive layer is scraped by about 1/3) is about 100,000 sheets at a diameter of 30 [mm], cleaning blade life (scraped due to poor cleaning) The life when this occurs is approximately 120,000 sheets. On the other hand, at a high linear pressure (100 [gf / cm]), the life of the photoconductor is about 20,000, the life of the cleaning blade is about 20,000, and the durability is 1/5 to 1/6. It can be said that

  On the other hand, as a cleaning method that suppresses mechanical rubbing that has good cleaning properties even when cleaning toner with a reduced particle size and spheroidization, and that can reduce film abrasion on the surface of the photoreceptor. There is an electric cleaning system.

  The cleaning device 20 includes a cleaning brush 23 as an electrostatic cleaning member, a recovery roller 24 as a recovery member, and a recovery roller cleaning blade 27 as a removal member that scrapes off the toner moved onto the recovery roller 24. Yes. The cleaning brush 23 is a brush roller that is driven to rotate about a brush rotation shaft, and a voltage is applied from the brush power source 30 through the rotation shaft (core metal). In addition, a voltage is applied to the collection roller 24 from the collection power supply 28 via a rotating shaft (core metal). Further, on the upstream side in the rotation direction of the photosensitive member 1 relative to the position where the cleaning brush 23 removes the residual transfer toner on the photosensitive member 1, a blade control power source 29 serves as a polarity control member for controlling the charging polarity of the residual transfer toner. A conductive blade 22 to which a negative voltage is applied is provided.

Here, the charge amount of the toner that adheres to the photosensitive member 1 as the transfer residual toner and reaches the portion facing the cleaning device 20 and the charging potential of the photosensitive member will be described. FIG. 2 is a graph showing the charge amount distribution of the toner on the photoconductor 1 before transfer and the charge amount distribution of the transfer residual toner remaining on the photoconductor 1 after transfer. The charge amount distribution was measured with an E-spurt analyzer manufactured by Hosokawa Micron. The vertical axis represents the ratio to the collected number, and the horizontal axis represents the charge amount of one toner. The number of toners collected this time was set to 500 because there was little toner remaining after transfer.
As shown in FIG. 2, most of the toner on the photoreceptor 1 before transfer is negatively charged. At the time of transfer, the toner on the photoconductor 1 is transferred to the transfer paper by the positive transfer bias applied to the transfer roller 15, but most of the toner charged positively before transfer is directly transferred to the photoconductor 1. Adhere to. Furthermore, even if the toner is negatively charged before transfer, the charged polarity is shifted to the positive side due to the positive charge injection applied to the transfer roller 15, and a part thereof is reversed to the positive polarity. There are things to do. Therefore, the untransferred toner on the photosensitive member 1 has a broad distribution in which the positive polarity toner and the negative polarity toner are mixed as shown in FIG.

  Further, the charge amount of the transfer residual toner when the environmental condition changes will be described. FIG. 3 shows that the usage environment is high temperature and high humidity (30 [° C.], 90 [%]), normal temperature and normal humidity (20 [° C.], 50 [%]), and low temperature and low humidity (10 [° C.], 15 [%]). 5 is a graph showing a charge amount distribution of toner before transfer in FIG. As shown in FIG. 3, since the toner is easily charged at low temperature and low humidity, the charge amount is increased. At high temperature and high humidity, the toner amount is difficult to be charged, and the charge amount is decreased. For this reason, the toner charge amount is distributed at a position where the negative charge amount is high at low temperature and low humidity, but at high temperature and high humidity, the toner charge amount is distributed at a position where the charge amount is lower than at low temperature and low humidity. When the toner on the photoconductor before transfer having a different charge amount distribution depending on the environment passes through the transfer portion, the charge amount distribution varies depending on each environment. FIG. 4 shows the charge amount distribution of the toner on the photoreceptor before transfer and the charge amount distribution of the transfer residual toner at high temperature and high humidity. FIG. 5 shows the charge amount distribution of the toner on the photoreceptor before transfer and the charge amount distribution of the residual toner after transfer at low temperature and low humidity. Note that FIG. 2 described above shows the charge amount distribution of the toner on the photoreceptor before transfer and the charge amount distribution of the residual toner after transfer at normal temperature and humidity. 2, 4, and 5, the transfer residual toner has a distribution in which the positive polarity side is increased at high temperature and high humidity compared to that at normal temperature and humidity, and the negative polarity side is increased at low temperature and low humidity. That is, at high temperature and high humidity, the transfer residual toner charge amount distribution on the photoreceptor 1 is shifted to the positive polarity side. Further, the charge amount of the transfer residual toner also changes depending on transfer conditions such as paper thickness.

  The transfer residual toner having such a charge amount distribution reaches a position facing the conductive blade 22 by the surface movement of the photoreceptor 1. FIG. 6 is an explanatory diagram of the conductive blade 22 when the surface of the photoreceptor 1 is moved. Part of the toner that reaches the portion facing the conductive blade 22 is mechanically scraped off, but stick slip (state C in the figure) occurs in the conductive blade 22 and part of the toner slips through.

  The conductive blade 22 is applied with a voltage of the same polarity (negative polarity) as that of the toner, for example, −450 V, and the transfer residual toner biased to the positive side passing through the conductive blade 22 is negative. To charge.

  The transfer residual toner charged to the negative polarity by the conductive blade 22 is transferred to the position of the cleaning brush 23 by the rotation of the photoreceptor 1. The cleaning brush 23 is supplied with a voltage having a polarity (positive polarity) opposite to the charging polarity of the toner from the brush power source 30, and electrostatically adsorbs the transfer residual toner that has passed through the conductive blade 22 to clean the cleaning brush 23. 23.

  The collection roller 24 is supplied with a positive voltage higher than that of the cleaning brush 23 from the collection power supply 28 via a cored bar, and electrostatically adsorbs the toner that has moved onto the cleaning brush 23 to collect the collection roller 24. Move up. The toner on the collection roller 24 is scraped off by the collection roller cleaning blade 27 and discharged to the outside by the toner discharge screw 19 or returned to the developing device 6.

Here, it will be described in detail that the charge polarity of the transfer residual toner changes when the transfer residual toner passes through the conductive blade 22 to which a negative voltage is applied.
The conductive blade 22 is an elastic body made of, for example, polyurethane rubber, has an electric resistance of 10 ⁶ to 10 ⁸ [Ω · cm], abuts against the photoreceptor 1 in the counter direction, and a contact pressure of 20 to 40 [g. / Cm]. Since the conductive blade 22 causes stick slip as described above, a part of the transfer residual toner passes through. When the transfer residual toner is sandwiched between the photosensitive member 1 and the conductive blade 22, the transfer residual toner is frictionally charged by the pressure between the photosensitive member 1 and the conductive blade, and the charging polarity is the normal charging polarity (negative polarity) of the toner. ) Shift to the side. Further, since a negative voltage is applied to the conductive blade 22, a current flows into the transfer residual toner and charges the transfer residual toner to a negative polarity. In addition, depending on the setting of the voltage applied to the conductive blade 22, a micro discharge may occur at the entrance and exit of the wedge formed by the photosensitive member 1 and the conductive blade 22, and more toner is applied by the micro discharge. Charges negative polarity with the same polarity as the voltage. That is, by applying a negative voltage to the conductive blade 22, the transfer residual toner is negatively charged, and a part of the transfer residual toner charged to the negative polarity side passes through the conductive blade 22. . FIG. 7 shows a transfer residual toner charge amount distribution at normal temperature and humidity and a transfer residual toner charge amount distribution after passing through the conductive blade 22. As shown in FIG. 7, by using the conductive blade 22, the transfer residual toner charge amount distribution on the photoreceptor 1 is shifted to the negative polarity side. The transfer residual toner that has shifted to the negative polarity side and passed through the conductive blade 22 is easily electrostatically removed by the cleaning brush 23 to which a positive voltage is applied.

A specific configuration of the conductive blade 22 applied to this embodiment is shown below. The conductive blade 22 was formed in a plate shape bonded on a sheet metal.
・ Shape: Thickness: 2 [mm], Free length: 7 [mm]
・ Hardness: 60-80 with JIS-A hardness meter, 30% rebound resilience
・ Electric resistance: 1 × 10 ⁶ [Ω ・ cm] (Mitsubishi Chemical's Hiresta measurement)
・ Contact condition to photoconductor: Counter direction
Contact angle: 20 [°]
Contact pressure: 20 [g / cm]
Biting amount: 0.7 [mm]

  The specific configuration of the conductive blade 22 described above is an example, and other values may be used. For example, if it is a JIS-A hardness meter, it may be in the range of 40-85. This is because the conductive blade 22 is a polarity control member that aligns the toner charge amount on one side in order to remove the transfer residual toner from the photosensitive member 1 with the cleaning brush 23, and therefore, there may be a lot of toner slipping. is there.

  Next, the cleaning brush 23 that removes toner from the photoreceptor 1 by electrostatic force will be described. The transfer residual toner that has passed through the conductive blade 22 reaches the position of the cleaning brush 23 to which a positive voltage is applied. However, since the brush fiber of the cleaning brush 23 is a conductive material, the photosensitive member 1 and the cleaning brush 23 are used. There is a possibility that charge injection from the cleaning brush 23 to the transfer residual toner occurs. Good electrostatic cleaning by the cleaning brush 23 is not performed on the transfer residual toner inverted to the positive polarity. In order to reduce such residual toner, it is desirable to reduce the charge injection to the residual transfer toner at the position of the cleaning brush 23 as much as possible.

  Therefore, in the printer of this embodiment, charge injection from the cleaning brush 23 is reduced. Charge injection is believed to occur as a current flows into the toner through the conductive material 32 in the brush fibers. Therefore, reduction of charge injection by the structure of the brush fiber will be described. 8 and 9 are sectional views of brush fibers 31 of a cleaning brush 23 that is generally used. In the brush fibers shown in FIGS. 8 and 9, the conductive material 32 is dispersed in the insulating material 33 on the surface layer of the brush fibers 31. In such a case, when the cleaning brush 23 cleans the untransferred toner, the contact between the conductive material 32 and the toner is increased, and current easily flows into the toner, so that charge injection is likely to occur.

  On the other hand, FIGS. 10 and 11 are cross-sectional views of the brush fibers 31 of the cleaning brush 23 provided in the cleaning device 20 of the present embodiment, FIG. 10 is a cross-sectional view of the first embodiment, and FIG. It is sectional drawing of the 1st Example. As shown in FIGS. 10 and 11, the brush fiber 31 of the cleaning brush 23 has a two-layered core-sheath structure in which the inside is made of a conductive material 32 and the surface portion is made of an insulating material 33. Since the surface layer of the brush fiber 31 having the core-sheath structure is the insulating material 33, the conductive material 32 and the toner are not in contact with each other except the cut surface of the fiber. Thereby, the charge injection to the toner removed from the cleaning brush 23 can be suppressed.

However, even in the case of the cleaning brush 32 having the core-sheathed brush fiber 31 as shown in FIGS. 10 and 11, the brush fiber 31 is directly provided along the normal direction of the peripheral surface of the brush roller core metal. In the case of a bristle brush, direct contact between the conductive agent and the toner occurs. If it demonstrates concretely, the electrically conductive agent which comprises the core part of the brush fiber 31 will be in the state exposed in the fiber cross section, ie, the front end surface of raising. In the case of a straight brush, as shown in FIG. 12, the tip surface of the brush fiber 31 faces the surface of the photoreceptor 1, and the toner on the surface of the photoreceptor and the tip surface of the brush fiber 31 are likely to contact each other. For this reason, the conductive agent exposed on the front end surface of the brush fiber 31 may come into contact with the toner to cause charge injection.
Therefore, in the present embodiment, as the cleaning brush 32, a so-called oblique hair brush in which brush fibers provided on the cylindrical core metal peripheral surface are inclined rearward in the rotational direction from the normal direction of the core metal peripheral surface ( It is also called a fallen brush.) In the case of such a slanted brush, as shown in FIG. 13, the tip surface of the brush fiber 31 hardly faces the surface of the photoreceptor 1. Is difficult to contact. Therefore, the conductive agent exposed on the tip surface of the brush fiber 31 hardly comes into contact with the toner to cause charge injection.

  Next, a site where charge injection occurs will be described in detail with reference to FIG. Note that the brush fibers of the cleaning brush 23 having the configuration shown in FIG. 14 are straight hairs. Charge injection into the toner occurs in a region E between the photosensitive member 1 and the cleaning brush 23 and a region F between the cleaning brush 23 and the collection roller 24 in FIG. In the region E, charge injection occurs at the moment when the toner comes into contact with the conductive material 32 of the brush fiber 31, and the toner with a low charge amount is reversed to the polarity on the applied voltage side. It passes through the cleaning brush 23 and becomes a cleaning residual toner. In addition, although the charge is injected even with the toner having a high charge amount, the polarity of the toner is not reversed because the charge amount is high, and the toner moves to the cleaning brush 23. Similarly, charge injection occurs in the region F, and the polarity of the toner with a low charge amount is reversed and does not move to the collecting roller 24 but remains on the cleaning brush 23, and meets the photosensitive member 1 again by the rotation of the cleaning brush 23. It adheres again to the body 1 and becomes a cleaning residual toner. Therefore, if the cleaning brush 23 is a slanted brush having a core-sheath structure as described above, the conductive material 32 of the fiber and the toner are difficult to contact as shown in FIG. In addition, charge injection between the cleaning brush 23 and the collection roller 24 can be reduced.

Next, it was confirmed that charge injection occurred in the region E and the region F.
In FIG. 15, from the configuration described with reference to FIG. 14, the transfer portion and the conductive blade 22 were removed, and the input toner to the cleaning brush 23 was changed to almost 100% negative toner after development and cleaned. Then, when the front end of the toner image has passed twice the circumference of the cleaning brush 23 from the contact portion between the cleaning brush 23 and the photosensitive member 1 (two rotations), the photosensitive member 1 is stopped and the second rotation of the cleaning brush 23 is performed. The toner q / d distribution on the photoconductor 1 corresponding to is measured. At this time, when the cleaning brush 23 rotates once after the cleaning of the toner image and meets the photosensitive member 1 again, the cleaning brush 23 is in contact with the recovery roller 24 once. The charge injection occurs, and the charge injection can be determined by measuring the toner q / d distribution on the photosensitive member 1 when the cleaning brush 23 rotates twice.

  In FIG. 16, in order to measure that charge injection occurs mainly between the cleaning brush 23 and the collection roller 24, the collection roller 24 and the collection roller cleaning blade 27 are removed from the configuration of FIG. It is a schematic block diagram of what applies a voltage to the axis | shaft 23a. The stop position of the photosensitive member 1 is the same as that in the configuration of FIG. 16, and the cleaning brush 23 is stopped by two rotations. Note that the brush fibers of the cleaning brush 23 configured as shown in FIGS. 15 and 16 are straight hairs. FIG. 17 is a schematic configuration diagram when the brush fibers of the cleaning brush 23 having the configuration shown in FIG.

FIG. 18 is a graph showing the results of comparison of the cleaning performance in the configurations of FIGS. 15, 16 and 17. In FIG. 18, the horizontal axis represents the voltage applied to the collection roller 24 or the cleaning brush 23, and the vertical axis represents the remaining cleaning ID.
The cleaning residual ID on the vertical axis is obtained as follows. First, the toner on the photosensitive member 1 after being cleaned by the cleaning brush 23 is tape-transferred with a scotch tape. Next, it is affixed on this scotch tape paper, and it is measured with a spectrocolorimeter (X light manufactured by Amtec Corporation). On the other hand, the cleaning residual ID is a value obtained by pasting only the tape with a scotch tape and measuring with a spectrocolorimeter, and subtracting only the tape with the scotch tape from the reflection density on the photoreceptor 1. There is a correlation between the ID and the number of toners, and the ID value increases when the number of toners is large. Therefore, the cleaning property can be determined by the ID.

  As shown in FIG. 18, the cleaning residual ID value is lower in the configuration of FIG. 16 than in the configuration of FIG. 15, and in the configuration of FIG. 17 than in the configuration of FIG. The remaining cleaning toner when the applied voltage is increased is all applied voltage polarity side, that is, charge-injected toner. Conversely, the remaining cleaning ID with a lower applied voltage is a toner that cannot be cleaned. In this case, all cleaning residual IDs of 500 [V] or more are positive toners. On the other hand, all the toners of 200 [V] (100 V in the configuration of FIG. 16) or less are negative polarity toners. As can be seen from FIG. 18, charge injection occurs between the photosensitive member 1 and the cleaning brush 23, and between the cleaning brush 23 and the collection roller 24, respectively. Also, from the result of the configuration shown in FIG. 17, it can be seen that almost no charge injection occurs when a slanted hair brush with a core-sheath structure is used as the brush fiber of the cleaning brush 23.

A specific configuration of the cleaning brush 23 applied to this embodiment is shown below.
-Cleaning brush material: Conductive polyester, Hair length: 5 [mm]
・ Cleaning brush yarn resistance: 10 ⁸ [Ω · cm]
・ Cleaning brush flocking density: 10 [10,000 / inch ² ]
-Amount of biting into the photoreceptor: 1 [mm]
-Cleaning brush applied voltage: +350 [V]

  As the insulating fiber constituting the brush fiber of the cleaning brush roller 23, an insulating material such as nylon, polyester (PET (polyethylene terephthalate)), acrylic, or rayon can be used. Representative fibers having a core-sheath structure are disclosed in JP-A-10-310974, JP-A-10-131035, JP-A-1-292116, JP-B-7-33637, and JP-B-7-33606. What was indicated by gazette, Japanese Patent Publication No. 3-64604 gazette, etc. can be used.

  The amount of oblique hair (falling amount) of the cleaning brush 23 is appropriately set according to the diameter of the photoreceptor 1 and the collection roller 24, and the toner on the photoreceptor 1 and the collection roller 24 and the brush of the cleaning brush 23 are set. It is set as appropriate so that the fiber tip faces do not contact each other. The oblique brushing method of the cleaning brush 23 is a method in which a straight hair brush having a longer brush fiber length is accommodated in a jig having the same inner diameter as that of the cleaning brush 23 and heat is applied to the cleaning brush 23. Alternatively, the hair can be inclined by rotating the jig.

  When the spherical toner is used, toner removal from the photosensitive member 1 by the conductive blade 22 is less than when the pulverized toner is used. Since the toner charge amount is aligned on one side at 22 and removed from the photoreceptor 1 with the cleaning brush 23, good cleaning performance can be obtained.

  Next, the collection roller 24 will be described in detail. The collection roller 24 only needs to have a function of transferring the toner adhering to the cleaning brush 23 to the collection roller 24 with a potential gradient between the cleaning brush 23 and the collection roller 24. Therefore, unlike the photoconductor 1, the collection roller 24 is not restricted by photoconductivity. The material can be arbitrarily selected. For example, spherical toner can be easily removed by coating the surface of the collection roller 24 with a material having a low coefficient of friction, or by winding an insulating tube having a low coefficient of friction around a metal roller. Further, it is preferable to provide an insulating surface layer on the collection roller 24 in order to prevent charge injection into the toner as described above. Specific examples of the insulating surface material used for the insulating surface layer include a PVDF tube, a PI tube, an acrylic coat, a silicone coat (for example, a PC containing silicone particles), ceramics, and the like.

  However, even when the surface layer of the collection roller 24 is formed of an insulating layer, it has been confirmed that a cleaning defect occurs on the surface of the photoreceptor over time. Regarding this cause, it can be easily guessed that the electric field between the cleaning brush 23 and the collecting roller 24 has weakened and the toner attached to the cleaning brush 23 cannot be sufficiently collected by the collecting roller 24. However, the bias value applied to the collecting roller 24 did not change and remained at a normal value. Therefore, the present inventors paid attention to the surface potential of the collecting roller 24 and measured the surface potential, and it was found that the surface potential of the collecting roller 24 decreased with time.

Here, a mechanism for collecting toner by the electrostatic cleaning method will be described.
19A and 19B show toner transfer from the surface of the photoreceptor (OPC) to the surface of the collection roller 24, the photoreceptor surface potential Vopc, the surface potential Vb of the cleaning brush 23, and the surface of the collection roller 24. It is explanatory drawing shown by the relationship with the electric potential Vr.
As the collection roller 24, a surface layer made of an insulating layer is used. The toner is negatively charged, the charge amount on the photoconductor is Q1, the charge amount is Q2 on the cleaning brush 23, the charge amount on the recovery roller 24 is Q3, and the surface of the photoconductor The potential Vopc is assumed to be 0 [V]. Then, the toner on the photoconductor moves to the cleaning brush 23 under the action of an electric field formed by a potential difference (V1 = Vb) between the photoconductor and the cleaning brush 23. This movement is called primary cleaning. Further, the toner on the cleaning brush 23 moves to the collection roller 24 under the action of an electric field formed by a potential difference (V2 = Vr−Vb) between the cleaning brush 23 and the collection roller 24. This movement is called secondary cleaning.

  In the secondary cleaning, as shown in FIG. 19A, if the potential difference V2 between the cleaning brush 23 and the collection roller 24 can be sufficiently secured, sufficient toner for moving the toner on the cleaning brush 23 to the collection roller 24 can be obtained. An electric field can be formed. However, if the surface potential of the recovery roller 24 decreases for some reason and the potential difference V2 between the cleaning brush 23 and the recovery roller 24 becomes small as shown in FIG. 19B, the toner on the cleaning brush 23 is removed from the recovery roller 24. A sufficient electric field for moving to the position cannot be formed, and secondary cleaning cannot be performed. Accordingly, the cause of the decrease in the surface potential of the recovery roller 24 was examined. When the toner on the recovery roller 24 was removed from the recovery roller 24 by the recovery roller cleaning blade 27, the surface potential of the recovery roller 24 decreased. Confirmed to do. This is because when the toner on the collection roller 24 is removed from the collection roller 24, a relatively strong peeling discharge occurs between the collection roller surface and the toner, and a counter charge is accumulated on the surface of the collection roller 24. I guess. If the surface layer of the collection roller 24 is an insulating layer, the surface potential that is lowered by such counter charge cannot be sufficiently recovered by the bias applied to the shaft portion of the collection roller 24, and the collection roller 24 It is considered that the surface potential of the film decreases with time.

  In order to prevent the surface potential of the collection roller 24 from decreasing with time, in this embodiment, a power supply (not shown) is connected to the collection roller cleaning blade 27 to remove the toner to be removed by the cleaning brush 23. Charges having the opposite polarity to the polarity (negative polarity) are applied to the surface of the collection roller 24. Specifically, a bias higher by about 400 to 800 [V] than the bias applied to the shaft portion of the collection roller 24 is applied to the surface of the collection roller 24 via the collection roller cleaning blade 27. The charge may be applied to the surface of the collection roller 72 by a charge application unit different from the collection roller cleaning blade 27.

  For the same reason, the surface potential of the cleaning brush 23 may decrease with time. Therefore, in this embodiment, in order to prevent the surface potential of the cleaning brush 23 from decreasing with time, a voltage application member connected to a power source (not shown) is brought into contact with the surface of the cleaning brush 23. This voltage application member is downstream in the rotation direction of the cleaning brush 23 with respect to the position where the cleaning brush 23 contacts the recovery roller 24, and the rotation direction of the cleaning brush 23 with respect to the position where the cleaning brush 23 contacts the photoreceptor 1. It contacts the cleaning brush 23 at a position on the upstream side. As a result, a charge having a polarity opposite to the polarity (negative polarity) of the toner to be removed by the cleaning brush 23 is applied to the surface of the cleaning brush 23. Specifically, a bias higher by about 200 to 500 [V] than the bias applied to the shaft portion of the cleaning brush 23 is applied to the surface of the cleaning brush 23 by the voltage application member.

A specific configuration of the collection roller 24 of the present embodiment is shown below.
・ Recovery roller material: Metal core SUS
Surface insulating layer Acrylic coat 10 [μm]
・ Recovery roller diameter: 10 [mm]

A specific configuration of the collection roller cleaning blade 27 of the present embodiment is shown below.
・ Recovery roller blade contact angle: 20 [°]
-Amount of biting into the collection roller: 1 [mm]
・ Recovery roller blade material: Polyurethane rubber

  As in this embodiment, an electrostatic cleaning method is used in which the transfer residual toner on the photoreceptor 1 as an image carrier is electrostatically moved to the surface of the cleaning brush 23 and removed by the cleaning brush 23 as an electrostatic cleaning member. The spherical toner on the photoconductor can be removed without increasing the linear pressure on the photoconductor, as in the case of a blade cleaning method in which the cleaning blade is brought into contact with the photoconductor to remove residual toner on the photoconductor. can do. Therefore, it is possible to suppress the shortening of the service life of the photosensitive member and the cleaning member.

Next, features of the present embodiment will be described.
As shown in FIG. 19A, even if the potential from the photoreceptor to the collecting roller is sufficient, if the toner is not sufficiently negatively charged, the toner cannot be transferred electrostatically. It becomes. Therefore, it is very important that the toner is sufficiently negatively charged.
When the toner image on the photosensitive member is transferred to the transfer paper and the image forming operation is completed, the photosensitive member 1, the developing roller 8, the transfer roller 15, the supply screw 9, the stirring screw 10, the toner discharge screw 19, the cleaning brush 23, and the recovery are collected. The rotational drive of the roller 24 stops. When this image forming operation is completed and the photosensitive member 1 is stopped, there may be a case where residual transfer toner remains between the contact portion of the cleaning brush 23 and the downstream portion of the contact portion of the transfer roller 15 on the photosensitive member 1. In general, it is known that a charged object loses its charged charge by natural discharge unless it continues to supply charge over time. This also applies to the toner. If the period until the next image forming operation is long, the transfer residual toner remaining on the photoreceptor loses its charged charge.

  FIG. 20 shows the untransferred toner immediately after passing through the conductive blade 22 from the downstream side of the contact portion of the conductive blade 22 as the polarity control member on the photoreceptor 1 to the contact portion of the cleaning brush 23 (area A in FIG. 21). And the charge distribution of the residual toner after the lapse of time. As shown in the figure, immediately after passing through the conductive blade 22, it is frictionally charged by the pressure of the photosensitive member 1 and the conductive blade 22 and shifted to the normal charging polarity side. It can be seen that the charge is lost with time and the charge distribution is shifted to the center.

  As described above, the transfer residual toner (toner C shown in FIG. 22) remaining in the area A shown in FIG. 21 cannot receive electrostatic force with respect to the positive potential of the cleaning brush 23 in the next image forming operation. . For this reason, it is impossible to transfer from the photosensitive member to the cleaning brush, and as shown in FIG. 23, it passes through the cleaning brush 23 and causes an abnormal image (background stain).

  Further, the transfer residual toner (toner D shown in FIG. 24) remaining on the cleaning brush 23 at the end of image formation loses its charge if the period until the next image forming operation is long. Therefore, during the next image forming operation, the cleaning brush 24 cannot transfer to the collecting roller 24 having a higher potential than the cleaning brush 23, and passes through the collecting roller 24 and stays on the cleaning brush 23 as shown in FIG. Or the reverse transfer from the cleaning brush 23 to the photosensitive drum 1 to cause an abnormal image (background stain image).

  Therefore, in the present embodiment, the cleaning mode is executed after the image formation is completed so that the toner does not remain on the area A and the cleaning brush 23 shown in FIG.

FIG. 26 is a block diagram of a configuration including a control unit 200 as a control unit that executes the cleaning mode after the end of image formation. The control unit 200 may be a main control unit that controls overall image formation of the printer 100, or may be a control unit provided separately from the main control unit.
The control unit 200 is connected to a photoconductor motor 201 that rotates the photoconductor, a brush motor 202 that rotates the cleaning brush 23, and a collection motor 203 that rotates the collection roller 24. A blade power supply 29, a recovery power supply 28, a brush power supply 30 and the like are also connected.

After the transfer of the toner image on the photoreceptor onto the transfer sheet and the image forming operation is completed, the control unit 200 executes the cleaning mode, and the toner remains on the area A and the cleaning brush 23 shown in FIG. The photoconductor motor 201, the brush motor 202, and the collection motor 203 are driven until the photoconductor 1, the cleaning brush 23, and the collection roller 24 are rotated until they disappear. Further, the control unit 200 controls the blade power supply 29, the recovery power supply 28, and the brush power supply 30 to apply a predetermined voltage to the conductive blade 22, the cleaning brush 23, and the recovery roller 24. Specifically, the cleaning mode is changed until the toner remaining between the contact portion of the cleaning roller 23 from the downstream side of the contact portion of the transfer roller 15 on the photosensitive member 1 is transferred to the cleaning brush 23 and transferred to the recovery roller 24. Run.
When the cleaning mode is executed, as shown in FIG. 27, the transfer residual toner B remaining on the surface of the photoconductor after the end of image formation is electrostatically transferred to the cleaning brush 23 as shown in FIG. Electrostatic transfer to Alternatively, as shown in FIG. 29, the recovery roller 24 is scraped from the recovery roller 24 by the recovery roller cleaning blade 27. This suppresses toner from remaining on the area A and the cleaning brush 23 shown in FIG. As a result, when the next image forming operation is opened for a long period of time, it is possible to suppress the toner that has lost the charged charges from remaining in the region A of FIG. be able to.

Next, a verification experiment for verifying the effect when the cleaning mode is executed after the image forming operation is completed will be described.
The verification experiment was performed in a high-temperature and high-humidity environment where the charge of the toner is easily lost. Then, an image output operation was performed using the printer (Ricoh's imago Neo C600) having the configuration shown in FIG. The specific configuration of the printer used in the verification experiment is shown below.
(Cleaning brush)
・ Material: Conductive polyester ・ Bristles length: 3 [mm]
・ Diameter: 12 [mm]
(Recovery roller)
・ Material: Core: SUS,
Surface layer: Acrylic coat 10 [μm]
・ Diameter: 10 [mm]
(Applied voltage)
-Conductive blade: -450 [V]
・ Cleaning brush: +350 [V]
・ Recovery roller: +650 [V]

The image output conditions of the verification experiment are shown below.
(Image output conditions)
-Number of output sheets: A4 horizontal 100 sheets-Experiment environment: 30 [° C] Humidity 80 [%]
・ Output image: 5% image area chart ・ Toner: Ricoh P × P toner prototype

[Example 1]
After the image forming operation was completed under the above image output conditions, the cleaning mode was executed until the transfer residual toner on the photoconductor was collected by the collection roller. Then, after 3 days had passed as a sufficient time, the image forming operation was performed again under the image output conditions.

  In Example 1, the output image after the lapse of 3 days had no background stain and a normal output image could be obtained. This is because, after the image formation is completed, the cleaning mode is performed to remove the transfer residual toner on the surface of the photoconductor and the surface of the cleaning brush. This is probably because the toner that lost the toner does not remain. Further, when the untransferred toner that lost the charged charge adhering to the collecting roller at the start of the image forming operation after the lapse of 3 days was observed, there was no reverse transfer from the collecting roller to the brush.

[Comparative Example 1]
After the image forming operation was completed under the above-described image output conditions, the image forming operation was performed again under the above-described image output conditions after the lapse of 3 days without executing the cleaning mode.

  In Comparative Example 1, the output image after the elapse of 3 days was a background stain image in which toner adhered to the background portion. This is presumably because the transfer residual toner that has lost the charged charge adhering to the photosensitive member at the start of the image forming operation after three days has passed through the cleaning brush without electrostatically adhering to the cleaning brush. In addition, when the transfer residual toner that lost the charged charge attached to the cleaning brush at the start of the image forming operation after the lapse of 3 days was observed, it remained on the cleaning brush without being electrostatically transferred to the collecting roller. .

[Example 2]
The execution time of the cleaning mode was extended as compared with Example 1, and the transfer residual toner on the photosensitive member was scraped off from the collection roller by the collection roller cleaning blade.

  In Example 2, as in Example 1, the output image after the elapse of 3 days had no background stain and a normal output image could be obtained. Further, when the transfer residual toner adhering to the cleaning roller cleaning blade at the start of the image forming operation after the lapse of 3 days was observed, it did not reversely transfer to the recovery roller.

[Comparative Example 2]
The execution time of the cleaning mode was made shorter than that in Example 1, and the cleaning mode was completed with the transfer residual toner on the photoreceptor adhered to the cleaning brush.

  In Comparative Example 2, as in Comparative Example 1, the output image after the elapse of 3 days was a background stain image in which toner adhered to the background portion. This is presumably because the transfer residual toner that lost the charged charge adhering to the cleaning brush at the start of the image forming operation after the lapse of 3 days retransferred onto the photoconductor. In addition, when the transfer residual toner that lost the charged charge attached to the cleaning brush at the start of the image forming operation after the lapse of 3 days was observed, it remained on the cleaning brush without being electrostatically transferred to the collecting roller. .

In the above-described embodiment, the conductive blade is used as the polarity control member. However, the polarity control member is not limited as long as it retains the function of aligning the charging polarity of the transfer residual toner on the photoreceptor 1 to the negative polarity. The shape of the conductive blade 22 is not limited to the above.
For example, the polarity control member may be a corona charger 122 shown in FIG. Each applied voltage condition in this case is as follows.
・ Polarity control corona charger: Wire: -4.0 [kV]
・ Cleaning brush: +350 [V]
・ Recovery roller: +650 [V]

The polarity control member may be a brush roller 222 shown in FIG. Each applied voltage condition in this case is as follows.
・ Polarity control brush roller: -700 [V]
・ Cleaning brush: +350 [V]
・ Recovery roller: +650 [V]

Furthermore, the polarity control member may be a fixed brush 322 shown in FIG. Each applied voltage condition in this case is as follows.
・ Polarity control fixed brush: -700 [V]
・ Cleaning brush: +350 [V]
・ Recovery roller: +650 [V]

In the above-described embodiment, the cleaning brush 23 is used as the electrostatic cleaning member. However, the electrostatic cleaning member may retain the function of electrostatically removing the transfer residual toner on the photoreceptor 1. For example, it is not limited to the form of the cleaning brush 23 as described above.
For example, the electrostatic cleaning member may be the cleaning roller 123 shown in FIG. The cleaning roller 123 is a roller made of SUS or the like provided with an insulating surface layer in the same manner as the recovery roller described above. In FIG. 33, the toner remaining electrostatically attached to the cleaning roller 123 is scraped off by the blade member 127, whereby the transfer residual toner is removed from the cleaning roller 123. Each applied voltage condition in this case is as follows.
-Conductive blade: -450 [V]
・ Cleaning roller: +650 [V]

  In the above-described embodiment, the charging roller 3 as a charging unit for charging the surface of the photoconductor is disposed in a non-contact manner on the surface of the photoconductor 1 with a predetermined distance. However, as shown in FIG. You may let them. Further, not only the charging roller 3, but also a corona charger 3a as shown in FIG. The charging means may be a magnetic brush 3b as shown in FIG. 36 or a fur brush 3c as shown in FIG.

[Photoreceptor Example 1]
Next, an example of a photoreceptor (hereinafter referred to as “photoreceptor example 1”) that is preferably used in the printer of this embodiment will be described.
In the photoreceptor of this photoreceptor example 1, a conductive support is heated to 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, plasma CVD is performed on the support. An amorphous silicon photoconductor (hereinafter referred to as “a-Si-based photoconductor”) having a photoconductive layer made of amorphous silicon (a-Si) by a film forming method such as the above method. Among them, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support is preferably used.

The layer structure of the a-Si photoconductor is, for example, as follows.
FIG. 38 is a schematic configuration diagram for explaining a layer configuration.
In the electrophotographic photoreceptor 500 shown in FIG. 38A, a photoconductive layer 502 made of a-Si: H, X and having photoconductivity is provided on a support 501. H is a hydrogen atom, and X is a halogen atom (F, Cl, Br, I).
An electrophotographic photoreceptor 500 shown in FIG. 38B includes a photoconductive layer 502 made of a-Si: H, X and having photoconductivity, and an amorphous silicon surface layer 503 on a support 501. It is configured.
An electrophotographic photoreceptor 500 shown in FIG. 38C has a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501; an amorphous silicon surface layer 503; And an amorphous silicon based charge injection blocking layer 504.
In the electrophotographic photoreceptor 500 shown in FIG. 38D, a photoconductive layer 502 is provided on a support 501. This photoconductive layer 502 includes a charge generation layer 505 and a charge transport layer 506 made of a-Si: H, X, and an amorphous silicon-based surface layer 503 is provided thereon.

  The support for the photoreceptor 1 may be conductive or electrically insulating. Examples of the conductive support include metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof such as stainless steel. Also, at least the surface on the side where the photosensitive layer is to be formed of an electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide or other synthetic resin film or sheet, glass or ceramic. A conductively treated support can also be used. The shape of the support can be a cylindrical or plate-like or endless belt with a smooth or uneven surface, and the thickness thereof is appropriately determined so that a desired photoreceptor for an image forming apparatus can be formed. When flexibility as a photoreceptor for an image forming apparatus is required, it can be made as thin as possible within a range where the function as a support can be sufficiently exhibited. However, the support is usually 10 [μm] or more from the viewpoint of manufacturing and handling, such as mechanical strength.

  As shown in FIG. 38C, the a-Si photosensitive member has a function of blocking the injection of charges from the conductive support side between the conductive support and the photoconductive layer as necessary. It is more effective to provide a charge injection blocking layer. That is, the charge injection blocking layer has a function of blocking charge injection from the support side to the photoconductive layer side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. When charged, it has a so-called polarity dependency that does not exhibit such a function. In order to provide such a function, the charge injection blocking layer contains a relatively large number of atoms for controlling conductivity as compared with the photoconductive layer. The layer thickness of the charge injection blocking layer is preferably 0.1 to 5 [μm], more preferably 0.3 to 4 [μm], from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. Is preferably 0.5 to 3 [μm].

  The photoconductive layer is formed on the undercoat layer as necessary, and the layer thickness of the photoconductive layer 502 is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, preferably 1 to 100 [μm], more preferably 20 to 50 [μm], and most preferably 23 to 45 [μm].

The charge transport layer is a layer mainly having a function of transporting charges when the photoconductive layer is functionally separated.
The charge transport layer includes at least silicon atoms, carbon atoms, and fluorine atoms as constituent elements, and is formed of a-SiC (H, F, O) including hydrogen atoms and oxygen atoms as required. It has conductive properties, in particular charge retention properties, charge generation properties and charge transport properties. In the present invention, it is particularly preferable to contain an oxygen atom.
The layer thickness of the charge transport layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. The charge transport layer is preferably 5 to 50 [μm], more preferably 10 It is desirable to be set to ˜40 [μm], optimally 20 to 30 [μm].

The charge generation layer is a layer mainly having a function of generating charges when the photoconductive layer is functionally separated.
This charge generation layer is composed of a-Si: H containing at least Si atoms as components and substantially no carbon atoms and, if necessary, hydrogen atoms, and has desired photoconductive properties, particularly charge generation properties. Have charge transport properties.
The layer thickness of the charge generation layer is appropriately determined as desired from the viewpoints of obtaining desired electrophotographic characteristics and economic effects, etc., preferably 0.5 to 15 [μm], more preferably 1 to 10 [μm]. ], Optimally, 1 to 5 [μm].

If necessary, the a-Si photosensitive member can be further provided with a surface layer on the photoconductive layer formed on the support as described above, thereby forming an amorphous silicon-based surface layer. It is preferable. This surface layer has a free surface and is provided mainly to achieve a desired purpose in terms of moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability.
The thickness of the surface layer is preferably 0.01 to 3 [μm], preferably 0.05 to 2 [μm], and most preferably 0.1 to 1 [μm]. . If the layer thickness is less than 0.01 [μm], the surface layer is lost due to wear or the like during use of the photoreceptor, and if it exceeds 3 [μm], electrophotographic characteristics such as an increase in residual potential are deteriorated. Seen.

[Photoreceptor Example 2]
Next, another example of a photoreceptor (hereinafter referred to as “photoreceptor example 2”) that is preferably used in the printer of this embodiment will be described.
The photoconductor of this photoconductor example 2 is an organic photoconductor using a crosslinkable charge transport material.
As the binder composition of the protective layer, a protective layer having a crosslinked structure is also effectively used. Regarding the formation of a cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used to cause a cross-linking reaction using light or thermal energy to form a three-dimensional network structure. is there. 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 a very effective means to use a monomer having a 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.
The reactive monomer having charge transporting ability includes a compound containing at least one charge transporting component and a silicon atom having a hydrolyzable substituent in the same molecule, and a charge transporting component in the same molecule. A compound containing a hydroxyl group, a compound containing a charge transporting component and a carboxyl group in the same molecule, a compound containing a charge transporting component and an epoxy group in the same molecule, a charge transporting component in the same molecule And a compound containing an isocyanate group. 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 viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, low surface energy, and reduction of friction coefficient. be able to. As these polymerizable monomers and oligomers, known ones can be used.

In Photoreceptor Example 2, the hole transporting compound is polymerized or cross-linked using heat or light. When the polymerization reaction is carried out by heat, the polymerization reaction proceeds when only the thermal energy proceeds. Although an initiator may be required, it is preferable to add an initiator in order to advance the reaction efficiently at a lower temperature.
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 embodiment, 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.

Specific examples of the photoreceptor that can be suitably used in the present embodiment include 182 parts of methyltrimethoxysilane, 40 parts of dihydroxymethyltriphenylamine, 225 parts of 2-propanol, 106 parts of 2% acetic acid, and 1 part of aluminum trisacetylacetonate. To prepare a coating solution for the protective layer, apply and dry the coating solution on the charge transport layer, heat cure at 110 ° C. for 1 hour, and form a protective layer with a film thickness of 5 [μm]. What was formed can be used.
Further, 30 parts of the hole transporting compound represented by the structural formula (I) shown in the chemical formula 1 below, an acrylic monomer of the structural formula (II) shown in the chemical formula 2 below and a photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl) -Ketone) is dissolved in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane to prepare a coating material for the surface protective layer, and this coating material is applied onto the above charge transport layer by a spray coating method. Further, it is possible to suitably use a surface protective layer having a film thickness of 5 [μm] by curing for 30 seconds with a light intensity of 500 [mW / cm ² ] using a metal halide lamp.

[Photoreceptor Example 3]
Next, still another example (hereinafter referred to as “photoreceptor example 3”) of a photoreceptor suitably used in the printer of the present embodiment will be described.
The photoconductor of this photoconductor example 3 is a photoconductor in which a filler is added to the protective layer for the purpose of improving wear resistance. Examples of organic fillers include fluororesin powders such as polytetrafluoroethylene, silicone resin powders, and a-carbon powders. Inorganic fillers include metal powders such as copper, tin, aluminum, and indium, tin oxide, and oxidation. Examples thereof include zinc, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, metal oxides such as tin-doped indium oxide, and inorganic materials such as potassium titanate. These fillers may be used alone or in combination of two or more. These fillers can be dispersed by using a suitable disperser in the protective layer coating solution. The average particle size of the filler is preferably 0.5 [μm] or less, and preferably 0.2 [μm] or less from the viewpoint of the transmittance of the protective layer. In the present invention, a plasticizer or a leveling agent may be added to the protective layer 21.

[Toner Example]
Next, an example of toner that is preferably used in the printer of this embodiment will be described.
As the toner of this embodiment, a toner having a shape factor SF1 of 100 to 150 is preferable.
FIG. 39 is an explanatory diagram for obtaining the shape factor SF1, and FIG. 40 is an explanatory diagram for obtaining the shape factor SF2.
As shown in FIG. 39, the shape factor SF1 is a numerical value indicating the ratio of the roundness in the shape of the spherical material, and the square of the maximum length MXLNG of an elliptical shape formed by projecting the spherical material on a two-dimensional plane. Divided by the graphic area AREA and multiplied by 100π / 4. That is, SF1 is calculated by the following mathematical formula (1).
SF1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
Further, as shown in FIG. 40, the shape factor SF2 is a numerical value indicating the ratio of unevenness in the shape of the substance, and the square of the perimeter PERI of the figure formed by projecting the substance on the two-dimensional plane is represented by the figure area AREA. It is expressed as a value obtained by dividing by 100 / 4π. That is, SF2 is calculated by the following mathematical formula (2).
SF2 = {(PELI) ² / AREA} × (100 / 4π)
For the shape factor SF2, a toner image was randomly sampled 100 times using an FE-SEM (S-800) manufactured by Hitachi, Ltd., and the image information was sent via an interface to an image analysis apparatus (LUSEX3) manufactured by Nicole. It is calculated from the above formula after being introduced into

  In the present embodiment, as shown in FIG. 41, the photosensitive member 1 and the cleaning device 20 may be integrally supported in a frame 83, and the process cartridge 300 may be detachably attached to the printer body. In this embodiment, in addition to the photosensitive member 1 and the cleaning device 20, the charging roller 3 and the developing device 6 are integrally supported. However, at least the photosensitive member 1 and the cleaning device 20 are integrally supported. If it is.

  In the present embodiment, an example of a so-called monochrome image forming apparatus is used, but a color image forming apparatus may be used. Hereinafter, a specific example in which the feature points of the present embodiment are applied to a color image forming apparatus will be described.

[Color image forming apparatus example 1]
FIG. 42 is a diagram showing an example in which the present invention is applied to a printer which is a so-called tandem type full-color image forming apparatus.
This printer includes an intermediate transfer belt 69 as an intermediate transfer member that is stretched around a plurality of rollers 64, 65, 67, and 68 so as to be elongated in the horizontal direction when installed on a horizontal plane. ing. The intermediate transfer belt 69 moves on the surface in the direction of arrow D in the figure. Four photoconductors 1Y, 1M, 1C, and 1K are arranged side by side on a plane portion of the intermediate transfer belt 69 extending in the horizontal direction. Around each of the photoreceptors 1K1Y, 1M, and 1C, as in the above-described embodiment, the charging devices 3K, 3Y, 3M, and 3C, the developing devices 6K, 6Y, 6M, and 6C, the charge removal lamps 8K, 8Y, 8M, and 8C, cleaning devices 7K, 7Y, 7M, 7C and the like are provided. The printer also includes a paper feed cassette (not shown) that stores transfer paper P as a plurality of recording materials. The transfer paper P in the paper feeding cassette is adjusted in timing by a pair of registration rollers (not shown) one by one by a paper feeding roller (not shown), and then is transferred to a secondary transfer region between the secondary transfer roller 66 and the intermediate transfer belt 69. Sent out.

  When image formation is performed in the printer of FIG. 42, first, the photosensitive members 1K, 1Y, 1M, and 1C are driven to rotate counterclockwise in FIG. 42 and the intermediate transfer belt 69 is driven to rotate counterclockwise in FIG. . Then, after the surfaces of the photoconductors 1K, 1Y, 1M, and 1C are uniformly charged by the charging devices 3K, 3Y, 3M, and 3C, image data is applied to the surfaces of the photoconductors 1K, 1Y, 1M, and 1C. The modulated laser beams LK, LY, LM, and LC are irradiated to form electrostatic latent images of the respective colors on the surfaces of the photoconductors 1K, 1Y, 1M, and 1C. Each color electrostatic latent image on the surface of each photoconductor 1K, 1Y, 1M, 1C is adhered to each color toner by each developing device 6K, 6Y, 6M, 6C, thereby forming each color toner image. The color toner images are primarily transferred onto the intermediate transfer belt 69 so as to overlap each other. The respective color toner images on the intermediate transfer belt 69 are transferred onto the transfer paper conveyed to the secondary transfer region by the secondary transfer roller 66 in a state where they overlap each other. The transfer paper on which the toner image is transferred in this manner is conveyed to a fixing unit (not shown), and the transfer paper is heated and pressurized to fix the toner image on the transfer paper to the transfer paper. The fixed transfer paper is discharged onto a paper discharge tray (not shown). The transfer residual toner remaining on the surfaces of the photoreceptors 1K, 1Y, 1M, and 1C after the transfer is removed by the cleaning devices 20K, 20Y, 20M, and 20C. Further, the transfer residual toner remaining on the surface of the intermediate transfer belt 69 is removed by the intermediate transfer belt cleaning device 120. The intermediate transfer belt cleaning device 120 also has the same configuration as the cleaning device 20.

  In the tandem type full-color image forming apparatus shown in FIG. 42, as described above, the cleaning device 20 is used as a cleaning unit that cleans the transfer residual toner remaining on the surfaces of the photoreceptors 1K, 1Y, 1M, and 1C. In addition, even with a spherical toner, the transfer residual toner can be satisfactorily removed from the surface of the photoreceptor over time. Similarly, the transfer residual toner that is not transferred onto the transfer paper and remains on the surface of the intermediate transfer belt 69 can be obtained by using the above-described cleaning device as the intermediate transfer belt cleaning device 120, even if it is a spherical toner. The transfer residual toner can be satisfactorily removed from the surface of the transfer belt with time. Further, after the image formation is completed, a cleaning mode is executed, and the transfer residual toner remaining on the surface of the photoreceptor is removed by the cleaning device 20. Further, after the image formation is completed, the intermediate transfer member cleaning mode is executed, and the transfer residual toner remaining on the intermediate transfer belt 69 is removed by the intermediate transfer belt cleaning device 120. As a result, even if the interval between the next image formations is long, it is possible to obtain a good image with no background stain.

[Color image forming apparatus example 2]
FIG. 43 is a diagram showing an example in which the present invention is applied to a printer which is a so-called one-drum type full-color image forming apparatus.
In this printer, one photoconductor 1 is housed in a main body housing (not shown). Around the photosensitive member 1, as in the above-described embodiment, there are a charging device 3, four developing devices 6C, 6M, 6Y, and 6K, an intermediate transfer unit 70 as a transfer unit, a cleaning device 20, a static elimination lamp 2, and the like. Is provided. The four developing devices 6C, 6M, 6Y, and 6K correspond to cyan (C), magenta (M), yellow (Y), and black (K) colors, respectively. The printer also includes a paper feed cassette (not shown) that stores a plurality of transfer sheets as recording materials. The transfer paper in the paper feed cassette is fed to a secondary transfer area between the secondary transfer roller 77 and the intermediate transfer belt 69 after the timing is adjusted by a pair of registration rollers (not shown) one by one by a paper feed roller (not shown). It is.

  When image formation is performed in the printer of FIG. 43, first, the photosensitive member 1 is rotationally driven counterclockwise in FIG. 43 and the intermediate transfer belt 69 is rotationally driven clockwise in FIG. Then, after uniformly charging the surface of the photosensitive member 1 with the charging device 3, the surface of the photosensitive member 1 is irradiated with the laser light L modulated with the C image data, and the surface of the photosensitive member 1 is subjected to C. Forming an electrostatic latent image. The electrostatic latent image for C is developed with C toner by the developing device 6C. The C toner image thus obtained is primarily transferred onto the intermediate transfer belt 69. Thereafter, the transfer residual toner remaining on the surface of the photoreceptor 1 is removed by the cleaning device 20, and then the surface of the photoreceptor 1 is again uniformly charged by the charging device 3. Next, the surface of the photoconductor 1 is irradiated with laser light L modulated with M image data to form an M electrostatic latent image on the surface of the photoconductor 1. The electrostatic latent image for M is developed with M toner by the developing device 6M. The M toner image thus obtained is primarily transferred onto the intermediate transfer belt 69 so as to overlap with the C toner image that has already been primarily transferred onto the intermediate transfer belt 69. Thereafter, Y and K are similarly primary-transferred onto the intermediate transfer belt 69. In this way, the color toner images on the intermediate transfer belt 69 that are overlapped with each other are transferred onto the transfer paper conveyed to the secondary transfer region by the secondary transfer roller 77. The transfer paper on which the toner image has been transferred in this manner is conveyed by a paper conveyance belt 79 to a fixing unit (not shown). In this fixing unit, the transfer paper is heated and pressurized to fix the toner image on the transfer paper to the transfer paper. The fixed transfer paper is discharged onto a paper discharge tray (not shown). The transfer residual toner remaining on the surface of the photoreceptor 1 after the transfer is removed by the cleaning device 20. Further, the transfer residual toner remaining on the surface of the intermediate transfer belt 69 is removed by the intermediate transfer belt cleaning device 120. The intermediate transfer belt cleaning device 120 also has the same configuration as the cleaning device 20.

  In the one-drum type full-color image forming apparatus shown in FIG. 43, as described above, the cleaning device 20 according to the present embodiment is used as a cleaning unit for cleaning the transfer residual toner remaining on the surface of the photosensitive member 1. Even with toner, the transfer residual toner can be satisfactorily removed from the surface of the photoreceptor over time. Similarly, the transfer residual toner that is not transferred to the transfer paper and remains on the surface of the intermediate transfer belt 69 may be spherical toner by using the cleaning device of the present embodiment as the intermediate transfer belt cleaning device 120. Transfer residual toner can be satisfactorily removed from the surface of the intermediate transfer belt with time. In addition, a cleaning mode is executed after the image formation is completed, the transfer residual toner remaining on the surface of the photosensitive member is removed by the cleaning device 20, and the transfer residual toner remaining on the intermediate transfer belt 69 is removed by the intermediate transfer belt cleaning device 120. Therefore, even if the interval between the next image formations is long, a good image with no background stain can be obtained.

  Further, as shown in FIG. 44, a cleaning device having the same configuration as the cleaning device 20 of the present embodiment may be used as a transport belt cleaning unit that removes toner adhering to the paper transport belt 81. In the printer 100 shown in FIG. 44, when a paper jam occurs, the toner image on the photosensitive member 1 is transferred to the paper transport belt 81, and the paper transport belt 81 becomes dirty. In addition, a toner with a low charge amount in the developing roller 8 or a positively charged toner may adhere between sheets on the photoreceptor 1. The toner adhering between the papers is transferred to the paper transport belt 81 and soils the paper transport belt 81. A part of the toner adhering to the paper conveyance belt 81 due to a paper jam or the like is charged by the transfer roller 15 and the polarity is reversed. As a result, the toner transferred as dirt on the paper transport belt 81 has both positive and negative polarities. However, by using the conveyance belt cleaning device 220 having the same configuration as the cleaning device 20 of the present embodiment as the paper conveyance belt cleaning means, the toner on the paper conveyance belt 81 having a mixture of positive and negative polarities is removed. It can be removed well.

  Further, by executing the paper transport belt cleaning mode after the image formation is completed, the toner remaining on the surface of the paper transport belt is removed by the transport belt cleaning device 220, so that the toner is transferred to the surface of the paper transport belt 81 during the next image formation. It can suppress remaining. Therefore, even when the next image formation is opened for a long period of time, there is almost no toner remaining on the surface of the paper transport belt 81 from which the charged charges have been lost. The transfer paper can be prevented from being soiled when the image formation is opened for a long time.

  As described above, according to the image forming apparatus of the present embodiment, the photosensitive member 1 that is an image carrier, the charging roller 3 that is a charging unit that charges the photosensitive member, and the exposure that exposes the photosensitive member 1 to form an electrostatic latent image. An exposure device as a means, a developing device as a developing means for converting the electrostatic latent image on the photoconductor 1 into a toner image, a transfer roller 15 as a transfer means for transferring the toner image on the photoconductor to a transfer material, and a photoconductor A cleaning brush 23 is provided as a surface-movable electrostatic cleaning member for electrostatically moving the upper transfer residual toner to its surface and removing it. Further, after the image formation is completed, a control unit 200 is provided as a control unit that executes a cleaning mode for removing the transfer residual toner on the photoconductor. With such a configuration, it is possible to suppress the transfer residual toner from remaining on the surface of the photoconductor during the next image formation. Therefore, even if the next image formation is opened for a long period of time, there is almost no toner remaining on the surface of the photosensitive member that has lost the charged charge. It is possible to suppress the occurrence of background stains on the formed image when the is opened for a long time.

  In addition, a recovery roller 24 is provided as a recovery member that moves and recovers toner adhering to the cleaning brush 23 to its own surface, and the cleaning mode is executed until the transfer residual toner on the photoreceptor is recovered by the recovery roller 24. The control unit 200 is configured to do this. As a result, the transfer residual toner remaining on the cleaning brush during the next image formation can be almost eliminated. Therefore, even if the next image formation is opened for a long period of time, the transfer residual toner from which the charged charges are lost does not remain on the cleaning brush. Therefore, the toner remains on the cleaning brush without being collected by the collection roller. It is possible to suppress the occurrence of transfer residual toner and transfer residual toner that reversely transfers from the cleaning brush to the photosensitive member.

  Further, by using a spherical toner having a shape factor SF-1 of 100 to 150, it is possible to measure high image quality, and it is a spherical toner that is harder to clean than pulverized toner by mechanical cleaning. Even if it exists, favorable cleaning can be performed by cleaning using the cleaning apparatus 20. Further, a spherical toner having a high roundness with a shape factor SF-1 of 100 to 150 is used as the spherical toner. When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photosensitive member 1 becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity becomes high. The attracting force with the body also becomes weak, the transfer rate can be increased, and a high-quality image can be obtained.

  Further, in a so-called one-drum type full-color image forming apparatus that includes a plurality of developing devices that form toner images on a photoconductor and forms a multicolor image by superimposing a plurality of toner images formed on the photoconductor. By executing the cleaning mode after completion of image formation, a good full-color image free from background stains can be obtained.

  In addition, a so-called tandem type image forming apparatus that includes a plurality of photoconductors and a developing device that forms toner images on the plurality of photoconductors, and forms a multicolor image by superimposing the toner images formed on the plurality of photoconductors. In the full-color image forming apparatus, a good full-color image free from background stains can be obtained by executing the cleaning mode after completion of image formation.

In addition, a paper transport belt 81 that is a transport member that transports transfer paper as a transfer material to a transfer position by the transfer roller 15 and a transport belt that is a transport member cleaning unit that electrostatically removes unnecessary toner adhering to the paper transport belt. In a printer comprising a cleaning device 220,
After the image formation is completed, the control unit 200 is configured to execute a conveyance belt cleaning mode for removing unnecessary toner on the paper conveyance belt. Thereby, it is possible to suppress the transfer residual toner from remaining on the surface of the paper conveyance belt 81 during the next image formation. Therefore, even if the next image formation is opened for a long period of time, there is almost no toner remaining on the surface of the paper conveyance belt 81 from which the charged charges have been lost. It is possible to prevent the transfer paper from becoming dirty when the next image formation is opened for a long time.

  Further, by using a material made of a surface layer or a material in which a filler is dispersed in the photosensitive layer as the photosensitive member 1, the amount of film scraping of the photosensitive member 1 can be reduced, and the wear resistance can be improved. . As a result, it is possible to suppress the surface of the photoconductor from being shaved and uneven due to wear. As a result, the contact pressure between the photoconductor and the cleaning blade is kept uniform in the axial direction, and it is possible to suppress the occurrence of a portion where the contact pressure between the photoconductor and the cleaning blade where toner slips easily occurs, The toner can be prevented from slipping through.

  Further, by using an organic photoreceptor having a surface layer reinforced with a filler or an organic photoreceptor using a cross-linked charge transport material as the photoreceptor 1, the amount of film scraping of the photoreceptor can be reduced.

  Further, by using an amorphous silicon photoconductor as the photoconductor 1, the amount of film scraping of the photoconductor 1 can be reduced, and wear can be suppressed. As a result, it is possible to suppress the surface of the photoconductor from being shaved and uneven due to wear. As a result, the contact pressure between the photoconductor and the cleaning blade is kept uniform in the axial direction, and it is possible to suppress the occurrence of a portion where the contact pressure between the photoconductor and the cleaning blade where toner slips easily occurs, The toner can be prevented from slipping through.

  Further, the process cartridge 300 integrally including at least one of the photoreceptor 1 and at least the charging roller 3, the developing device 6, and the cleaning brush can be easily attached to and detached from the printer. Thereby, the operativity at the time of replacement | exchange improves.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. 6 is a graph showing a charge amount distribution immediately before transfer of toner carried on a photoconductor and a charge amount distribution of transfer residual toner remaining on the photoconductor after transfer. FIG. 6 is a diagram illustrating a charge amount distribution of toner on a photoreceptor before transfer in each environment. FIG. 6 is a diagram showing a toner charge amount distribution on a photoconductor before transfer and a toner charge amount distribution on the photoconductor after transfer in a high-temperature and high-humidity environment. FIG. 6 is a diagram illustrating a toner charge amount distribution on a photoreceptor before transfer and a toner charge amount distribution on the photoreceptor after transfer in a low-temperature and low-humidity environment. Explanatory drawing of the braid | blade at the time of the photoreceptor surface movement. 3 is a graph showing a charge amount distribution after transfer of toner carried on a photoconductor and a charge amount distribution of untransferred toner that has passed through a portion facing a conductive blade. Sectional drawing of the conventional brush fiber. Sectional drawing of the conventional brush fiber. Sectional drawing of a brush fiber. Sectional drawing of a brush fiber. The longitudinal cross-sectional view in case the brush fiber of a cleaning brush is an oblique hair. The longitudinal cross-sectional view in case the brush fiber of a cleaning brush is straight hair. Explanatory drawing of the site | part which electric charge injection generate | occur | produces with a cleaning brush. The schematic block diagram of the structure which removed the transfer part and the electroconductive blade from the structure of FIG. The schematic block diagram of the structure which removes the collection | recovery roller and the collection | recovery roller blade from the structure of FIG. 15, and applies a voltage to the axis | shaft of a cleaning brush. The schematic block diagram of the structure which used the brush fiber of the cleaning brush of the structure of FIG. The graph which shows the result of having compared the cleaning property in the structure of FIG.15, FIG16 and FIG.17. (A) and (b) show the relationship between toner transfer from the surface of the image carrier to the surface of the collection roller, and the image carrier surface potential Vopc, the surface potential Vb of the cleaning brush, and the surface potential Vr of the collection roller. It is explanatory drawing. 3 is a graph showing a charge distribution of a transfer residual toner immediately after passing through a conductive blade and a charge distribution of a transfer residual toner after a lapse of time between a cleaning blade contact portion and a downstream side of the contact portion of the conductive blade on the photoreceptor. FIG. 10 is a diagram illustrating a region where residual toner that passes without being electrostatically transferred to a cleaning brush remains when an interval of the next image forming operation is opened. FIG. 3 is a diagram illustrating transfer residual toner remaining on the surface of a photoreceptor when image formation is completed. FIG. 23 is a diagram illustrating a state in which the transfer residual toner illustrated in FIG. 22 has passed without being attached to the cleaning brush during the next image forming operation. FIG. 4 is a diagram illustrating transfer residual toner remaining on a cleaning brush at the end of image formation. FIG. 25 is a diagram showing a state in which the transfer residual toner shown in FIG. 24 continues to adhere to the brush roller without being collected by the collecting roller during the next image forming operation. The block diagram of the structure provided with the control part which performs cleaning mode after completion | finish of image formation. FIG. 3 is a diagram illustrating transfer residual toner remaining on the surface of a photoreceptor when image formation is completed. FIG. 28 is a diagram illustrating a state in which the transfer residual toner illustrated in FIG. 27 is attached to the collection roller after the cleaning mode is executed. FIG. 28 is a diagram illustrating a state in which the untransferred toner illustrated in FIG. 27 is attached to the recovery roller cleaning blade after the cleaning mode is executed. The figure which shows the structure which used the polarity control member as the corona charger. The figure which shows the structure which used the polarity control member as the brush roller. The figure which shows the structure which used the polarity control member as the fixed brush. The figure which shows the structure which used the electrostatic cleaning member as the cleaning roller. FIG. 3 is a diagram illustrating a configuration in which a charging roller is brought into contact with a photosensitive member. The figure which shows the structure which used the charging means as the corona charger. The figure which shows the structure which used the charging means as the magnetic brush brawler. The figure which shows the structure which used the charging means as the fur brush roller. Explanatory drawing of the layer structure of an amorphous silicon photoconductor. The figure which represented the shape of the toner typically in order to demonstrate shape factor SF-1. The figure which represented the shape of the toner typically in order to demonstrate shape factor SF-2. FIG. 2 is a schematic configuration diagram of a process cartridge. 1 is a main part configuration diagram of a tandem full-color image forming apparatus. 1 is a block diagram of the main part of a one-drum type full-color image forming apparatus. The schematic block diagram of the structure provided with the cleaning apparatus in the paper conveyance belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charging roller 6 Developing apparatus 8 Developing roller 15 Transfer roller 19 Toner discharge screw 20 Cleaning apparatus 22 Conductive blade 23 Cleaning brush 24 Collection roller 27 Collection roller cleaning blade 28 Collection power supply 29 Blade power supply 30 Brush power supply 31 brush fiber

Claims (8)

An image carrier;
Charging means for charging the image carrier;
Exposure means for exposing the image carrier to form an electrostatic latent image;
Developing means for converting the electrostatic latent image on the image carrier into a toner image;
Transfer means for transferring a toner image on the image carrier to a transfer material;
In an image forming apparatus comprising: a surface-movable electrostatic cleaning member that electrostatically moves and removes transfer residual toner on the image carrier to its own surface;
A polarity control member that is arranged upstream of the electrostatic cleaning member in the moving direction of the image carrier surface and controls the charging polarity of the transfer residual toner on the image carrier;
A collecting member for electrostatically moving and collecting the toner adhering to the surface of the electrostatic cleaning member to its own surface;
For a recovery member that removes toner adhering to the surface of the recovery member in contact with the surface of the recovery member and that imparts a charge opposite in polarity to the charge polarity of the toner adhering to the surface of the recovery member to the surface of the recovery member A cleaning blade;
And a control unit that executes a cleaning mode for removing transfer residual toner between the polarity control member and the electrostatic cleaning member in the image carrier surface movement direction after the image forming operation is completed. An image forming apparatus. The image forming apparatus according to claim 1.
The electrostatic cleaning member is
A cleaning brush having brush fibers of a core-sheath structure of a two-layer structure in which the inside is made of a conductive material and the surface portion is made of an insulating material,
The image forming apparatus, wherein the brush fibers are inclined toward the downstream side of the cleaning brush surface movement direction with respect to the normal direction of the peripheral surface of the metal core of the cleaning brush. The image forming apparatus according to claim 1 or 2,
An image forming apparatus, wherein the electrostatic cleaning member is provided with a voltage applying unit that applies a voltage having a polarity opposite to the charging polarity of the transfer residual toner controlled by the polarity control member. The image forming apparatus according to any one of claims 1 to 3 ,
Previous to the transfer residual toner on the Kizo bearing member is recovered by the recovery member, the image forming apparatus characterized by being configured the control unit to execute the cleaning mode. The image forming apparatus according to claim 1,
An image forming apparatus using a toner having a shape factor SF1 of 100 to 150 as the toner. The image forming apparatus according to claim 1,
An image forming apparatus using an image carrier in which a filler is dispersed as the image carrier. The image forming apparatus according to claim 1.
An image forming apparatus using an organic photoreceptor having a surface layer reinforced with a filler or an organic photoreceptor using a cross-linked charge transport material as the image carrier. The image forming apparatus according to claim 1,
An image forming apparatus characterized in that the image bearing member and at least one of the charging unit, the developing unit, and the electrostatic cleaning member are integrally supported to be a process cartridge that is detachable from the apparatus main body. apparatus.

Images