JP2010160448A - Cleaning device, and image forming apparatus and image carrier unit provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress degradation in cleaning performance by a cleaning brush, when a cleaning device concurrently uses a blade cleaning system and an electrostatic cleaning system is provided with a lubricant feeding mechanism, using a lubricant applying brush. <P>SOLUTION: By making a voltage applied to a cleaning blade 101 cleaning the surface of an intermediate transfer belt 70, the toner on the surface of the intermediate transfer belt is charged to negative polarity, thus the amount of the toner electrostatically adhered to a cleaning brush 102 performing electrostatic cleaning on the downstream side thereof is made large so as to improve the cleaning properties. Then, a lubricant application brush 104 is provided on the downstream side of the cleaning brush. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning device used in an image forming apparatus such as a copying machine, a facsimile machine, a printer, and the like, and an image forming apparatus and an image carrier unit having the same.

  Conventionally, as a cleaning means for removing toner remaining on an image carrier (a body to be cleaned) after transferring a toner image, a blade cleaning system in which a rubber cleaning blade is brought into contact with the surface of the image carrier to remove the toner. Things are known. In the blade cleaning method, if the degree of adhesion between the cleaning blade and the surface of the image carrier is low, the toner slips and the cleaning performance is likely to deteriorate. Therefore, in order to prevent this, the cleaning blade is usually pressed against the surface of the image carrier with a sufficiently strong contact pressure. However, when the cleaning blade is pressed against the surface of the image carrier with an extremely strong contact pressure, the cleaning blade is turned over, resulting in streaky or strip-like cleaning failure, and it is difficult to keep stable cleaning performance. . Further, in the long term, the film scraping on the surface of the image carrier is promoted to shorten the life of the image carrier, and the wear of the cleaning blade is promoted to shorten the life of the cleaning blade.

  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 size toner or spherical toner is used, sufficient cleaning performance cannot be obtained by the blade cleaning method as compared with the case where the pulverized toner is cleaned.

  Even with a small particle size toner or a spherical toner, if the contact pressure is extremely increased (for example, about 100 gf / cm or more in linear pressure), it is possible to obtain a certain level of cleaning performance even with a blade cleaning method. However, as described above, problems such as turning over of the cleaning blade and shortening of the life of the image carrier and the cleaning blade occur. In particular, regarding the life of the photosensitive member (image carrier) (the number of printed sheets until the photosensitive layer is scraped by about 1/3 of the original), the linear pressure of about 20 gf / cm generally used for cleaning of pulverized toner may be used. For example, a photoconductor with a diameter of 30 mm has about 100,000 sheets, and a linear pressure of 100 gf / cm gives about 20,000 sheets. The life of the cleaning blade (the number of prints until a cleaning failure occurs due to wear) is about 120,000 with a linear pressure of about 20 gf / cm, but about 20000 with a linear pressure of 100 gf / cm. It becomes.

  An electrostatic cleaning system as described in Patent Document 1 is a cleaning system that can provide good cleaning properties even for small-diameter toners and spherical toners and that can reduce the life of the image carrier. There is. In the electrostatic cleaning method of Patent Document 1, a conductive cleaning roller is provided so as to rub against the surface of the photosensitive member, and a voltage is applied to the cleaning roller. Is to be removed. For this reason, good cleaning properties can be obtained even for small-diameter toner and spherical toner. Further, in the cleaning device described in Patent Document 1, a voltage having a polarity opposite to that of the cleaning roller is in contact with the photoconductor on the upstream side in the movement direction of the photoconductor surface with respect to a position where the cleaning roller is in contact with the photoconductor. An applied conductive cleaning blade is provided.

  Generally, the transfer residual toner on the photoconductor has a broad charge polarity distribution, and the charge polarity is in a state where both positive and negative polarities are mixed. If the toner charging polarity is a mixture of positive and negative polarities, the toner charged to one polarity (usually the normal charging polarity of the toner) can be removed by the cleaning roller, but the toner charged to the other polarity (usually normal) The reversely charged toner charged to the opposite polarity to the charged polarity) cannot be removed. In the cleaning device described in Patent Document 1, the transfer residual toner is transferred after the cleaning blade passes through a position where the cleaning blade contacts the photoconductor (blade contact position). The charging polarity of the toner is set to the same polarity as the cleaning blade (usually the normal charging polarity of the toner). As a result, the transfer residual toner that has passed through the blade contact position and reached the position where the cleaning roller comes into contact with the photosensitive member (roller contact position) has the same charge polarity as that of the cleaning blade. Therefore, even after the transfer, even the transfer residual toner charged to a polarity opposite to the polarity can be electrostatically collected by the cleaning roller.

  In addition, with the electrostatic cleaning method, it is generally difficult to remove a large amount of toner at once, and if a large amount of toner is input to the roller contact position at a time, the toner cannot be completely cleaned, resulting in poor cleaning. There is. According to the cleaning device described in Patent Document 1, a blade cleaning method is used in combination with a cleaning roller that dams the toner by a cleaning blade and mechanically removes the toner upstream of the cleaning roller in the moving direction of the photoreceptor surface. Therefore, even if a large amount of toner is input to the roller contact position at once, most of the toner can be dammed up at the blade contact position. Thereby, even in a situation where a lot of toner has to be removed, it is possible to suppress a large amount of toner from being input to the roller contact position at a time, and to prevent the occurrence of defective cleaning.

In Patent Document 2, the brush part is moved so as to come into contact with the surface of the photoreceptor, and the lubricant adhered to the brush part is removed by removing the lubricant from the solid lubricant made of zinc stearate. There has been disclosed a cleaning device in which a lubricant application brush to be applied to is provided in a cleaning case in which a cleaning blade is disposed. In general, the lubricant is applied to the surface of the photoconductor for the purpose of reducing the coefficient of friction between the surface of the photoconductor and a member in contact therewith. For example, it is effective to apply a lubricant to the surface of the photosensitive member for the purpose of reducing the coefficient of friction between the surface of the photosensitive member and the cleaning blade in contact with the surface and preventing the cleaning blade from turning over.
Further, by providing the lubricant application brush in the cleaning case of the cleaning device, it is possible to prevent the scattering of the lubricant and the transfer residual toner adhering to the lubricant application brush by using the cleaning case. Therefore, according to the cleaning device described in Patent Document 2, a case for preventing the scattering of these separately from the cleaning case becomes unnecessary, and as a result, the limited space around the photosensitive member can be effectively used. .

  Generally, the toner is present between the cleaning blade and the surface of the photosensitive member, thereby exerting a lubricating function between them. Therefore, in the cleaning device described in Patent Document 1, if the toner input to the blade contact position is too small, the coefficient of friction between the cleaning blade and the surface of the photoreceptor increases, and the cleaning blade is turned up. Problems such as shortening the life of the photoconductor and the cleaning blade occur. For example, when a large amount of images having a low image area ratio such as character images are continuously printed, the toner input to the blade contact position is small, and such a problem is likely to occur. Therefore, in the cleaning device using both the blade cleaning method and the electrostatic cleaning method as in the cleaning device described in Patent Document 1, the lubricant is supplied to the surface of the image carrier as in the cleaning device described in Patent Document 2. It is effective to provide a lubricant supply mechanism.

Here, a problem found by the present inventors when a lubricant supply mechanism using a lubricant application brush is provided in a cleaning device using both a blade cleaning method and an electrostatic cleaning method will be described.
In general, not only the photoconductor but also the image carrier including the intermediate transfer belt and the like, the space around the image carrier is very limited, and it is important to save space around the image carrier. Yes. Compared to the case where the lubricant application brush is provided in the case of the cleaning device and the lubricant application brush is provided in a case separate from the case of the cleaning device, the space around the image carrier is reduced. Is effective. The structure of the lubricant application brush used for applying the lubricant to the surface of the image carrier is the same as the structure of the cleaning brush used in the electrostatic cleaning method. If attention is paid to this point, as shown in FIG. 16, the cleaning brush 202 is used as a lubricant application brush by a configuration in which the solid lubricant 205 is brought into contact with the cleaning brush 202. The configuration in which the lubricant is applied to the surface of the image carrier while electrostatically recovering the transfer residual toner on the surface of the intermediate transfer belt 70 in the illustrated example is limited to the periphery of the image carrier. This is even more effective in effectively using the space.
However, when such a configuration is adopted, the surface of the brush portion of the cleaning brush 202 is covered with a large amount of lubricant, and the portion where the toner can be electrostatically adsorbed on the surface of the brush portion is almost eliminated. The force that electrostatically attracts toner to the surface is weakened. This causes a problem that the cleaning performance of the cleaning brush 202 is deteriorated.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a lubricant supply mechanism using a lubricant application brush in a cleaning device using both a blade cleaning method and an electrostatic cleaning method. Even if it is a case, it is providing the cleaning apparatus which can suppress the fall of the cleaning performance by a cleaning brush, an image forming apparatus provided with the same, and an image carrier unit.

In order to achieve the above-mentioned object, the invention according to claim 1 cleans and applies the surface of the object to be cleaned by damming the toner on the surface of the object to be cleaned by contacting the surface of the object to be cleaned moving. A conductive cleaning blade for charging the toner on the surface of the object to be cleaned to a predetermined polarity by the applied voltage, and a brush so as to contact the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned A cleaning brush for cleaning the surface of the object to be cleaned by electrostatically adhering the toner charged to the predetermined polarity on the surface of the object to be cleaned to the brush part by the applied voltage while moving the part; In the cleaning apparatus having the cleaning blade and the cleaning case for storing the cleaning brush, Lubricant for applying the lubricant adhering to the brush part to the surface of the object to be cleaned while moving the brush part in contact with the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned An application brush is provided in the cleaning case.
Further, the invention of claim 2 is the cleaning device according to claim 1, wherein the predetermined polarity attached to the brush portion by an applied voltage while moving its surface so as to face the brush portion of the cleaning brush. The electrostatic charge toner is electrostatically attached to the surface of the self-recovery, the recovery rotary body for recovering the toner from the cleaning brush, and the surface of the recovery rotary body in contact with the surface of the recovery rotary body A removal blade that removes the toner from the surface of the recovery rotator by damming the toner above, and the brush portion of the lubricant application brush is in contact with the surface of the recovery rotator. A lubricant application brush is arranged.
According to a third aspect of the present invention, there is provided an image forming apparatus for forming an image on a recording material by transferring a toner image formed on the image bearing member from the image bearing member to a recording material. The cleaning device of claim 1 or 2 is used as a cleaning device for cleaning residual toner remaining on the image carrier after transfer.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the image forming apparatus further comprises a plurality of developing devices each containing toner of different colors, and the plurality of developing devices are arranged opposite to the one image carrier. The toner images are formed on the image carrier by attaching toners of different colors to the latent image on the image carrier by the plurality of developing devices.
According to a fifth aspect of the present invention, in the image forming apparatus according to the third aspect of the present invention, the image forming apparatus includes a plurality of developing devices each containing toner of different colors, and the same number of the image bearing members as the plurality of developing devices are provided. One developing device is arranged opposite to the image carrier, and each color toner is attached to each image carrier by attaching a different color toner to each latent image on each image carrier. An image is formed, and these toner images are superposed to form a toner image on a recording material finally.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, a photosensitive member made of a material in which a filler is dispersed is used as the image carrier.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the fourth to sixth aspects, an organic photoreceptor having a surface layer reinforced with a filler is used as the image carrier. It is a feature.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the fourth to seventh aspects, an organic photoreceptor using a cross-linked charge transport material is used as the image carrier. To do.
According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the fourth to sixth aspects, a photosensitive member having a photosensitive layer made of amorphous silicon is used as the image carrier. It is.
According to a tenth aspect of the present invention, in the image forming apparatus according to the third aspect, the toner image formed on the latent image carrier is transferred to the image carrier and finally formed on the recording material. It is what.
The invention according to claim 11 is an image forming apparatus for forming an image on the recording material by finally transferring the toner image formed on the image bearing member from the image bearing member onto the recording material. The cleaning device according to claim 1, further comprising a recording material conveying member that adsorbs and conveys the recording material to a surface thereof, and the cleaning device according to claim 1 or 2 as a cleaning device for cleaning toner adhering to the recording material conveying member. It is characterized by this.
According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the third to eleventh aspects, the toner has a shape factor SF1 of 100 or more and 150 or less. is there.
According to a thirteenth aspect of the present invention, an image carrier and a cleaning device for cleaning residual toner remaining on the image carrier after transfer are integrally supported and formed on the image carrier. In the image carrier unit that is detachable from the image forming apparatus that forms an image on the recording material by finally transferring the toner image from the image carrier onto the recording material, the cleaning device includes: The cleaning device according to claim 1 or 2 is used.

  According to the present invention, in a cleaning device using both a blade cleaning method and an electrostatic cleaning method, a lubricant application brush is disposed in a cleaning case separately from a cleaning brush. Therefore, the amount of lubricant adhering to the cleaning brush is reduced as compared with the case where the cleaning brush is used as a lubricant application brush. As a result, the deterioration of the cleaning performance of the cleaning brush due to the adhesion of the lubricant to the cleaning brush is suppressed.

1 is a schematic configuration diagram of a printer according to an embodiment. It is explanatory drawing which shows schematic structure of the belt cleaning apparatus used for the printer. 4 is a graph showing a charge distribution of a transfer residual toner before and after passing through a cleaning blade of the belt cleaning device. FIG. 17 is a graph showing the relationship between the pressure applied to the cleaning brush of the solid lubricant and the cleaning property in the belt cleaning device shown in FIG. 16. 5 is a graph showing the relationship between the amount of biting into the recovery roller of the lubricant application brush and the cleaning property in the belt cleaning device according to the embodiment. 6 is a graph showing the relationship between the ratio of the rotation speed of the lubricant application brush to the rotation speed of the collecting roller (rotation speed ratio) and the cleaning performance in the belt cleaning device. It is a schematic block diagram which shows the belt cleaning apparatus which concerns on a modification. 6 is a graph for explaining that a charge distribution of a transfer residual toner after passing through a cleaning blade of the belt cleaning device according to the embodiment changes according to an increase in an applied voltage to the cleaning blade. It is explanatory drawing for demonstrating the motion (stick-slip phenomenon) of the contact part of a cleaning blade. It is explanatory drawing of the layer structure of an amorphous silicon photoreceptor. FIG. 4 is a diagram schematically illustrating the shape of a toner for explaining a shape factor SF-1. FIG. 6 is a diagram schematically illustrating the shape of a toner for explaining a shape factor SF-2. It is a schematic block diagram of an image carrier unit. 1 is a configuration diagram of a main part of a one-drum type full-color image forming apparatus. It is a schematic block diagram of the structure provided with the cleaning apparatus in the paper conveyance belt. It is explanatory drawing which shows schematic structure of the belt cleaning apparatus using the cleaning brush as a lubricant application brush.

Hereinafter, an embodiment in which the present invention is applied to a printer which is an electrophotographic image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram of a printer according to the present embodiment.
This printer is a so-called intermediate transfer tandem image forming apparatus. This printer includes an intermediate transfer belt 70 that is an intermediate transfer member as an image carrier that is stretched around a plurality of support rollers 64, 65, 67, 68, and 69. The intermediate transfer belt 70 moves in the clockwise direction in the drawing. On the flat surface portion of the intermediate transfer belt 70 stretched between the two support rollers 64 and 65, the photoreceptors 1Y, 1M, 1C, and 1K as the latent image carriers are arranged to face each other. Around each of the photoreceptors 1Y, 1M, 1C, and 1K, charging rollers 3Y, 3M, 3C, and 3K as charging means, developing devices 6Y, 6M, 6C, and 6K as developing means, and discharge lamps 2Y and 2M, respectively. , 2C, 2K, and photoconductor cleaning devices 20Y, 20M, 20C, 20K, and the like. The printer also includes a paper feed cassette (not shown) that stores recording paper as a plurality of recording materials. The recording paper in the paper feeding cassette is adjusted by a pair of registration rollers (not shown) one by one by a paper feeding roller (not shown), and then sent to a secondary transfer region between the secondary transfer roller 66 and the intermediate transfer belt 70. It is.

  When image formation is performed in this printer, first, the photosensitive members 1Y, 1M, 1C, and 1K are rotated in the counterclockwise direction in the drawing, and the intermediate transfer belt 70 is rotated in the clockwise direction in the drawing. Then, the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K are uniformly charged by the respective charging rollers 3Y, 3M, 3C, and 3K, and then images are formed on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K. Laser light 4Y, 4M, 4C, and 4K modulated with data are irradiated to form electrostatic latent images of the respective colors on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K, respectively. Each color electrostatic latent image on the surface of each photoconductor 1Y, 1M, 1C, 1K is adhered to each color toner by developing devices 6Y, 6M, 6C, 6K, respectively, thereby forming each color toner image. Is done. Each color toner image is primarily transferred onto the intermediate transfer belt 70 so as to overlap each other. The respective color toner images on the intermediate transfer belt 70 are transferred onto the recording paper conveyed to the secondary transfer area by the secondary transfer roller 66 in a state where they overlap each other. The recording paper to which the toner image is transferred in this manner is conveyed to a fixing unit (not shown), and the recording paper is heated and pressurized to fix the toner image on the recording paper to the recording paper. The recording sheet after fixing is discharged onto a discharge tray (not shown). The transfer residual toner remaining on the surface of each photoreceptor 1 after the transfer is removed by the photoreceptor cleaning devices 20Y, 20M, 20C, and 20K. Further, the transfer residual toner remaining on the surface of the intermediate transfer belt 70 that is the object to be cleaned is removed by the belt cleaning device 100.

Next, the configuration of the belt cleaning apparatus 100 for cleaning the surface of the intermediate transfer belt 70, which is a characteristic part of the present invention, will be described.
FIG. 2 is an explanatory diagram showing a schematic configuration of the belt cleaning device 100.
The belt cleaning apparatus 100 includes a conductive cleaning blade 101 that cleans the surface of the intermediate transfer belt by contacting the surface of the intermediate transfer belt 70 and blocking toner on the surface of the intermediate transfer belt. On the downstream side of the cleaning blade 101 in the intermediate transfer belt surface movement direction, the brush portion is moved so as to be in contact with the intermediate transfer belt surface, and the positive polarity voltage (for example, +300 V) applied by the brush power source 102a is used as an intermediate. A cleaning brush 102 is provided for cleaning the surface of the intermediate transfer belt by electrostatically adhering a negatively charged toner (regular charging polarity) on the surface of the transfer belt to the brush portion. The cleaning brush 102 of this embodiment is rotationally driven in the counter direction with respect to the surface movement direction of the intermediate transfer belt 70.

  The cleaning blade 101 and the cleaning brush 102 are accommodated in a cleaning case 103. An inlet seal 103a and an outlet seal 103b are provided at the upstream end and the downstream end of the cleaning case 103 in the intermediate transfer belt surface moving direction. The inlet seal 103a is configured not to scrape off the toner on the intermediate transfer belt 70. Specifically, the inlet seal 103a is formed of polyurethane rubber having a thickness of 0.2 mm, the intermediate transfer belt 70 has a contact angle of 11 ° with respect to the surface of the intermediate transfer belt 70, and the bite amount is 1 mm. It is in contact with the surface of the belt 70.

  Here, most of the toner charge distribution (q / d distribution) on the intermediate transfer belt 70 is negatively charged (normally charged polarity) before passing through the secondary transfer region. However, by passing a secondary transfer bias of positive polarity when passing through the secondary transfer region, a part of the toner charge distribution before passing through the cleaning blade in FIG. It will be charged with a certain positive polarity. In this state, some of the toner cannot be electrostatically collected by the cleaning brush 102, and the cleaning performance by the cleaning brush 102 deteriorates. The toner charge distribution in this specification is 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. is there. The number of collections this time is 500 because there is little transfer residual toner.

  Therefore, in this embodiment, a negative polarity voltage (for example, -1200 V) is applied to the cleaning blade 101 by the blade power source 101a in order to return the reversely charged toner on the surface of the intermediate transfer belt to the negative polarity. As a result, most of the reversely charged toner can be returned to the negative polarity, which is the normal charge polarity, like the toner charge distribution after passing through the cleaning blade in FIG. As a result, the reversely charged toner can be returned to the normal charged polarity (minus polarity) before passing through the cleaning blade 101 and reaching the brush contact position of the cleaning brush 102, and the cleaning performance by the cleaning brush 102 can be improved. it can.

  In this embodiment, a negative polarity voltage is applied to the cleaning blade 101 by the blade power source 101a in order to charge the toner on the surface of the intermediate transfer belt to a negative polarity. Thus, even toner charged to a polarity opposite to the normal charging polarity (minus polarity) can be returned to the minus polarity before passing through the cleaning blade 101 and reaching the brush contact position of the cleaning brush 102. Therefore, the cleaning property by the cleaning brush 102 can be improved.

  Further, in this embodiment, the powder adhering to the brush portion while moving the brush portion so as to contact the surface of the intermediate transfer belt 70 on the downstream side of the cleaning brush 102 in the moving direction of the intermediate transfer belt surface. A lubricant application brush 104 for applying a lubricant to the surface of the intermediate transfer belt is also provided in the same cleaning case 103 as the cleaning blade 101 and the cleaning brush 102. The solid lubricant 105 urged by, for example, 4N is in contact with the lubricant application brush 104 in a direction in which the lubricant application brush 104 is pressed against the lubricant application brush 104 by a spring 105a. When the lubricant application brush 104 is driven to rotate, the solid lubricant 105 is scraped off by the brush portion, and thereby the powdery lubricant adheres to the brush portion. Then, the powdery lubricant is transported to the contact portion between the lubricant application brush 104 and the surface of the intermediate transfer belt 70 as the lubricant application brush 104 is rotationally driven while being adhered to the brush portion. Thus, a powdery lubricant is applied to the surface of the intermediate transfer belt.

  Further, in the belt cleaning device 100 of the present embodiment, the brush portion is applied to the brush portion by a positive polarity voltage applied by the recovery power source 107a while moving its surface so as to face the brush portion of the cleaning brush 102. A collection roller 107 is provided as a collection rotating body for collecting the toner from the cleaning brush 102 by electrostatically adhering the negatively charged toner adhering to the surface thereof. The voltage applied to the collection roller 107 is higher than the voltage applied to the cleaning brush 102, for example, + 700V. A removal blade 108 that removes toner from the surface of the collecting roller by abutting the toner on the surface of the collecting roller is in contact with the surface of the collecting roller 107. A positive polarity voltage is also applied to the removal blade 108 by the power source 108a, and the negatively charged toner adhering to the surface of the collection roller 107 is mechanically and electrostatically collected. .

  In the present embodiment, the brush portion of the lubricant application brush 104 is also in contact with the surface of the collection roller 107. As a result, both the toner attached to the brush portion of the cleaning brush 102 and the toner attached to the brush portion of the lubricant application brush 104 can be collected by the single collection roller 107.

Next, the belt cleaning device 100 will be described in more detail.
Transfer residual toner that is not transferred to the recording paper in the secondary transfer and remains on the intermediate transfer belt 70 is conveyed along with the surface movement of the intermediate transfer belt 70, passes through the seal portion of the inlet seal 103a of the cleaning case 103, and Get inside the cleaning case. Most of the transfer residual toner on the intermediate transfer belt 70 is mechanically removed by the cleaning blade 101, but part of the toner passes through the cleaning blade 101. In particular, when a small particle size toner or a spherical toner is used, the amount that passes through the cleaning blade 101 is large. The toner removed by the cleaning blade 101 is discharged to the outside of the belt cleaning device 100 by the recovery coil 106 in the cleaning case 103.

  The transfer residual toner that has passed through the cleaning blade 101 is then mechanically and electrostatically removed from the surface of the intermediate transfer belt 70 by the cleaning brush 102. Note that most of the untransferred toner that has passed through the cleaning blade 101 is unified to a negative polarity by a negative polarity voltage applied to the cleaning blade 101. Therefore, the toner can be efficiently electrostatically attached to the brush portion of the cleaning brush 102 to which the positive polarity voltage is applied, and high cleaning performance can be exhibited. The toner attached to the brush portion of the cleaning brush 102 is conveyed to a contact portion with the collection roller 107 as the cleaning brush 102 is driven to rotate. In this contact portion, the toner adhering to the brush portion of the cleaning brush 102 electrostatically moves to the collection roller 107 side and adheres to the surface of the collection roller 107. The toner adhering to the surface of the collection roller 107 is conveyed to a contact position with the removal blade 108 as the collection roller 107 is driven to rotate. At this time, it passes through the collection roller inlet seal 107 b in contact with the collection roller 107. The recovery roller inlet seal 107b is configured under the same conditions as the above-described inlet seal 103a, and the toner on the recovery roller 107 is not scraped off by the recovery roller inlet seal 107b and contacts the removal blade 108. It is transported to the position. The toner adhering to the surface of the collecting roller 107 is mechanically and electrostatically removed from the surface of the collecting roller at this contact position. The toner removed by the removal blade 108 is discharged to the outside of the belt cleaning device 100 by the recovery coil 106 in the cleaning case 103.

  The lubricant is applied by the lubricant application brush 104 to the surface of the intermediate transfer belt 70 cleaned by the cleaning blade 101 and the cleaning brush 102 in this way. The lubricant remaining on the lubricant application brush 104 without being applied to the intermediate transfer belt 70 moves toward the recovery roller 107 when contacting the recovery roller 107. The lubricant that has moved to the collection roller 107 is conveyed to a contact position between the collection roller 107 and the removal blade 108, leveled by the removal blade 108, and uniformly attached to the surface of the collection roller 107. As a result, the friction coefficient between the surface of the collection roller 107 and the removal blade 108 decreases, and a situation in which the removal blade 108 is swollen does not occur.

  In the present embodiment, the amount of biting between the cleaning brush 102 and the intermediate transfer belt 70 is 1.5 mm, the amount of biting between the cleaning brush 102 and the collection roller 107 is 1.5 mm, and the lubricant applying brush 104 and the intermediate transfer belt 70. The amount of biting between the lubricant application brush 104 and the collection roller 107 is 0.5 mm. The difference in the amount of biting of the cleaning brush 102 and the lubricant application brush 104 into the recovery roller 107 is that the amount of lubricant that has moved from the lubricant application brush 104 to the recovery roller 107 moves from the recovery roller 107 to the cleaning brush 102 is reduced. Therefore, the amount of lubricant movement from the lubricant application brush 104 to the collection roller 107 is reduced.

Next, toner cleaning with the cleaning brush 102 will be described in more detail.
The toner on the intermediate transfer belt 70 moves according to the potential difference between the voltage applied to the cleaning brush 102 and the surface potential of the intermediate transfer belt 70. The toner that has moved to the cleaning brush 102 electrostatically adheres to each brush surface of the cleaning brush 102 and is carried to the contact portion with the collection roller 107. The toner that electrostatically adheres to the brush surface of the cleaning brush 102 moves to the collection roller 107 side due to a potential difference between the cleaning brush 102 and the collection roller 107 by contacting or approaching the collection roller 107. Usually, when the amount of toner input to the cleaning brush 102 increases and exceeds a certain limit amount (experimentally 0.5 mg per unit area), the amount of toner passing through the cleaning brush 102 increases, resulting in poor cleaning. This is because the surface of each brush of the cleaning brush 102 is covered with toner, and the portion of the brush surface to which the toner is not attached decreases, so that the toner cannot move from the intermediate transfer belt 70 to the cleaning brush 102, and the cleaning brush 102 This is due to passing through 102. Therefore, in order to maintain the cleaning performance by the cleaning brush 102, it is important that as much as possible no deposits such as toner remain on the surface of each cleaning brush 102 in contact with the surface of the intermediate transfer belt 70.

  The deposits on the brush surface that can hinder the movement of the toner from the intermediate transfer belt 70 to the cleaning brush 102 are not limited to toner but also include a lubricant. Therefore, it is desirable to reduce the amount of lubricant that moves from the lubricant application brush 104 to the collection roller 107 and moves from the collection roller 107 to the cleaning brush 102. Therefore, in the present embodiment, as described above, the amount of biting between the lubricant application brush 104 and the collection roller 107 is reduced, and the amount of lubricant adhering to the cleaning brush 102 is reduced.

FIG. 4 is a graph showing the relationship between the pressure applied to the cleaning brush 202 of the solid lubricant 205 and the cleaning property in the belt cleaning device 200 shown in FIG.
This belt cleaning device 200 uses the cleaning brush 202 as a lubricant application brush by adopting a configuration in which the solid lubricant 205 is brought into contact with the cleaning brush 202. The graph shown in FIG. 4 shows that when the amount of toner input to the cleaning brush 202 is about 0.06 mg / cm ² , the pressure applied to the cleaning brush 202 by the solid lubricant is changed and passes through the cleaning brush 202. Then, the image density (cleaning residual ID) corresponding to the amount of toner adhering to the surface of the intermediate transfer belt 70 is measured. As can be seen from this graph, when the lubricant is applied to the intermediate transfer belt 70 using the cleaning brush 202, the cleaning residual ID is the cleaning force when the applied pressure of the solid lubricant 205 to the cleaning brush 202 becomes 2N or more. The remaining ID becomes 0.01 or more, and a cleaning failure occurs.

  In the belt cleaning apparatus 100 of this embodiment, as a method of reducing the amount of lubricant movement from the lubricant application brush 104 to the recovery roller 107, for example, the rotation speed of the lubricant application brush 104 is set to be higher than the rotation speed of the recovery roller 107. Also, a method of slowing down or reducing the flocking density of the lubricant application brush 104 can be considered. Specifically, for example, the rotational speed of the lubricant application brush 104 is set to about ½ of the rotational speed of the collection roller 107, and the flocking density of the lubricant application brush 104 is set to about ½ of the cleaning brush 102.

FIG. 5 is a graph showing the relationship between the amount of biting into the collection roller 107 of the lubricant application brush 104 and the cleaning performance when the amount of toner input to the cleaning brush 102 is 0.06 mg / cm ² .
In this graph, the residual cleaning ID is plotted on the vertical axis, and the amount of biting into the collection roller 107 of the lubricant application brush 104 is plotted on the horizontal axis. The circles in the graph indicate the case where the ratio of the rotational speed of the lubricant application brush 104 to the rotational speed of the collection roller 107 (rotational speed ratio) is 1/1. On the other hand, the x mark in the graph indicates the case where the rotation speed ratio is 1/2. As can be seen from this graph, when the rotational speed ratio is 1/1, the amount of biting into the collection roller 107 of the lubricant application brush 104 is 0.4 mm or less, and the rotational speed ratio is 1/2. In some cases, the amount of biting of the lubricant application brush 104 into the collection roller 107 may be 0.8 mm or less.

FIG. 6 is a graph showing the relationship between the rotational speed ratio and the cleaning performance when the amount of toner input to the cleaning brush 102 is 0.06 mg / cm ² .
In this graph, the cleaning residual ID is taken on the vertical axis, and the rotation speed ratio is taken on the horizontal axis. The circles in the graph indicate the case where the amount of biting into the collection roller 107 of the lubricant application brush 104 is 1.5 mm. On the other hand, the x mark in the graph indicates the case where the amount of biting is 0.5 mm. As can be seen from this graph, when the amount of biting is 1.5 mm, the rotational speed ratio is ½ or less, and when the amount of biting is 0.5 mm, the rotational speed ratio is 1 / 1 or less.

Here, a problem according to the amount of lubricant transferred from the lubricant application brush 104 to the collection roller 107 will be described.
Since a voltage is applied to the removal blade 108 that is in contact with the collection roller 107, the discharge product is likely to adhere to the surface of the collection roller, and this discharge product causes a gap between the collection roller 107 and the removal blade 108. The coefficient of friction tends to increase. Therefore, if the amount of lubricant transferred from the lubricant application brush 104 to the collection roller 107 is too small, the removal blade 108 is liable to bend.
The results of experiments on this are shown in Table 1 below.

  This Table 1 shows the relationship between the amount of biting of the lubricant application brush 104 into the collection roller 107 and the stagnation state of the removal blade 108 that is in contact with the collection roller 107. At this time, the rotation speed ratio of the lubricant application brush 104 to the recovery roller 107 is ½. As can be seen from Table 1, if the amount of biting of the lubricant application brush 104 into the collection roller 107 is too small, the amount of lubricant transferred from the lubricant application brush 104 to the recovery roller 107 is too small, and the removal blade 108 Drowning occurs.

  Conversely, when the amount of lubricant movement from the lubricant application brush 104 to the collection roller 107 is too large, the amount of lubricant movement from the collection roller 107 to the cleaning brush 102 increases. As a result, as described above, the cleaning performance of the cleaning brush 102 is degraded.

Thus, since the amount of lubricant transferred from the lubricant application brush 104 to the recovery roller 107 is too small or too large, a problem occurs. Therefore, the amount of lubricant transfer from the lubricant application brush 104 to the recovery roller 107 is increased. It is desirable to adjust to an appropriate amount.
In this embodiment, the amount of biting of the lubricant application brush 104 into the intermediate transfer belt 70 is 1.5 mm, the amount of biting of the lubricant application brush 104 into the collection roller 107 is 0.5 mm, and the lubricant with respect to the collection roller 107 is used. The rotation speed ratio of the application brush 104 was set to 1/2, and the flocking density of the lubricant application brush 104 was set to 50,000 / inch ² . According to this condition, in the printer according to the present embodiment, the removal blade 108 does not sag over time, and the cleaning performance on the intermediate transfer belt 70 by the cleaning brush 102 does not deteriorate.

FIG. 7 is a schematic configuration diagram illustrating a modified example of the belt cleaning device in which a voltage having the same polarity as that of the cleaning brush 102 is applied to the lubricant application brush 104.
Here, the voltage applied to the lubricant application brush 104 is the same as the voltage applied to the cleaning brush 102.
Normally, the toner on the intermediate transfer belt 70 to be cleaned by the belt cleaning device 100 is a transfer residual toner, and therefore the amount thereof is relatively small. However, for example, after the jam or in the discharge mode (for example, to keep the charge amount of the toner in the developing unit constant when printing an image with a small image occupying area) A large amount of toner is input to the belt cleaning device 100. Even in this case, most of the cleaning blade 101 can be removed by the cleaning blade 101 at the initial stage when it is new, but the amount of toner passing through the cleaning blade 101 increases with time due to wear of the cleaning blade 101. . If the amount of toner passing through the cleaning blade 101 is about 0.5 mg / cm ² or less, the cleaning brush 102 can sufficiently clean the toner. However, when a large amount of toner is input to the belt cleaning device 100 over time, an amount of toner that cannot be sufficiently cleaned by the cleaning brush 102 may pass through the cleaning blade 101. In this case, there is a possibility that the cleaning brush 102 cannot perform sufficient cleaning. However, as in the present modification, a voltage is applied to the lubricant application brush 104 to enable the lubricant application brush 104 to collect electrostatic toner. As a result, the occurrence of poor cleaning can be suppressed.

  Each brush surface of the lubricant application brush 104 is covered with a powdery lubricant, but it is not completely covered. Therefore, if the amount of toner is small, the lubricant application brush 104 can be cleaned. Is possible.

Next, a change in toner charging polarity when passing through the cleaning blade 101 to which a voltage (for example, −1200 V) having the same polarity as the normal charging polarity of toner is applied will be described.
In this embodiment, the electrical resistance of the cleaning blade 101 is about 10 ⁶ to 10 ⁸ Ωcm, and the cleaning blade 101 is attached to the intermediate transfer belt 70 so that the contact pressure with the intermediate transfer belt 70 is 20 to 40 g / cm. Against the counter from the counter direction. The toner that passes through the cleaning blade 101 is generated by the intermediate transfer belt 70 and the cleaning blade 101 in accordance with an increase in voltage applied to the cleaning blade 101 by frictional charging, charge injection, discharge, etc., as shown in FIG. Shift to the normal charging polarity (minus polarity) side.

  In general, as shown in FIG. 9, the cleaning blade 101 generates a so-called stick-slip phenomenon in which the contact state changes in the rotation direction of the intermediate transfer belt 70. When the cleaning blade 101 is in the state of the symbol L indicated by the dotted line in the figure, toner slip occurs. When the toner is sandwiched between the cleaning blade 101 and the intermediate transfer belt 70, a current flows into the toner with the voltage applied to the cleaning blade 101, and the toner is charged to the polarity on the applied voltage side and charged with the cleaning blade 101. Pass through. The change in the charging polarity of the toner in such a state is considered to be mainly due to discharge, but it is also considered to be due to charge injection into the toner.

  It has been confirmed that the surface potential of the intermediate transfer belt 70 after the transfer is approximately in the range of −100 V to +100 V, although it varies somewhat depending on the transfer conditions. Therefore, if the applied voltage to the cleaning blade 101 shown in FIG. 9 is, for example, -1200V, the surface potential of the intermediate transfer belt 70 is + 100V, the potential difference is 1300V, so that the discharge start voltage is exceeded and discharge occurs. Begins. The toner is charged to the same polarity as the applied voltage by the occurrence of discharge at the minute gap between the entrance and the exit of the wedge formed between the intermediate transfer belt 70 and the cleaning blade 101. As a result, the toner charge distribution (q / d distribution) after passing through the cleaning blade 101 is shifted to the negative polarity side.

  As described above, since the charging polarity of the toner passing through the cleaning blade 101 is unified to one polarity (the same polarity as the normal charging polarity of the toner in this embodiment), the toner passing through the cleaning blade 101 has its polarity. It is efficiently and electrostatically removed by the cleaning brush 102 to which a voltage of the opposite polarity is applied. Note that, over time, the wedge portion on the inlet side of the cleaning blade 101 is filled with the toner so as to block the toner, so that the discharge for charging the toner is mainly the discharge generated in the wedge portion on the outlet side. It is thought that it is.

  The applied voltage to the cleaning blade 101, the cleaning brush 102, the collection roller 107, the removal blade 108, etc. may have a polarity opposite to that described above.

Next, toner cleaning on the collection roller 107 will be described.
When the toner is difficult to clean with a blade, such as a spherical toner, it is difficult to remove the toner on the collection roller 107 as in the case of removing the toner on the photosensitive member and the intermediate transfer belt 70. . However, the surface condition of the collection roller 107 is not limited as long as the toner attached to the cleaning brush 102 can be electrostatically moved to the collection roller 107 side by the potential difference between the cleaning brush 102 and the collection roller 107. There are fewer restrictions than the surface conditions of the body and the intermediate transfer belt 70. Therefore, in the present embodiment, the surface of the collection roller 107 is coated with a material having a low coefficient of friction with toner (fluorine or the like), or a metal roller having a low coefficient of friction with the toner (tube such as PVDF or PFA). ) Is used. With such a configuration, even spherical toner or the like that is difficult to remove by blade cleaning on the photoreceptor or the intermediate transfer belt 70 can be sufficiently removed by blade cleaning.

  An example of various conditions of the belt cleaning apparatus 100 in this embodiment is shown below.

<Intermediate transfer belt 70>
・ Intermediate transfer belt linear velocity: 138 mm / s

<Cleaning blade 101>
・ Blade thickness: 2mm
・ Free length: 7mm
・ Measured value of JIS-A hardness meter: 60-80
・ Rebound resilience: 30%
・ Electric resistance: 10 ⁶ to 10 ⁸ Ω · cm
-Contact direction to the intermediate transfer belt 70: counter direction-Contact angle: 20 °
Contact pressure: 20g / cm
-Applied voltage: -1200V

<Cleaning brush 102>
・ Cleaning brush material: Conductive polyester, Hair length: 5mm
-Biting amount into the intermediate transfer belt 70: 1.5 mm
Cleaning brush linear velocity: 138 mm / s (same linear velocity as the intermediate transfer belt 70)
-Cleaning brush shaft applied voltage: + 300V
· Resistance of brush original yarn: 10 ⁷ Ω · cm, brush planting density: 100,000 / inch ²
・ Brush shape: Inclined to the downstream side of the brush rotation direction (slanted hair), Diameter: 15 mm
-Rotation direction: Counter direction with respect to the surface movement direction of the intermediate transfer belt 70-Biting amount into the collection roller 107: 1.5 mm

<Lubricant application brush 104>
-Lubricant application brush material: conductive polyester, hair length: 5mm
-Biting amount into the intermediate transfer belt 70: 1.5 mm
-Lubricant application brush linear velocity: 69 mm / s (1/2 of the cleaning brush linear velocity)
-Lubricant application brush shaft applied voltage: Float (+ 300V in the case of the above-described modification)
・ Brush yarn resistance: 10 ⁷ Ω · cm, brush flocking density: 50,000 / inch ²
・ Brush form: Inclined to the downstream side of the brush rotation direction (slanted hair), diameter 15mm
-Biting amount into the collection roller 107: 0.5 mm

<Recovery roller 107>
Collection roller material: SUS cored bar with PVDF tube (thickness 100 μm), surface layer: UV coating layer (thickness 5 μm: insulation)
・ Diameter: 14mm
・ Recovery roller linear speed: 138mm / s
・ Recovery roller shaft applied voltage: + 700V
Rotation direction: counter direction with respect to the rotation direction of the cleaning brush 102 and the rotation direction of the lubricant application brush 104

<Removal blade 108>
・ Blade thickness: 2mm
・ Free length: 7mm
・ Measured value of JIS-A hardness meter: 60-80
・ Rebound resilience: 30%
・ Electric resistance: 10 ⁶ to 10 ⁸ Ω · cm
-Contact direction to the collection roller 107: counter direction-Contact angle: 20 °
Contact pressure: 20g / cm
・ Applied voltage: + 1300V

<Inlet seal 103a and recovery roller inlet seal 107b>
・ Material: Polyurethane rubber ・ Thickness: 0.2mm
・ Free length: 7mm
-Contact angle to intermediate transfer belt or collection roller: 11 °
-Biting amount into the intermediate transfer belt or collection roller: 1 mm

<Outlet seal 103b>
・ Material: Polyurethane rubber ・ Thickness: 0.2mm
・ Free length: 7mm
-Contact angle to intermediate transfer belt or collection roller: 11 °
・ Amount of biting into the lubricant application brush 104: 1 mm

  When the toner is scraped off by the removal blade 108 on the surface of the collection roller 107, the surface potential of the collection roller 107 decreases. The reason for this is not yet clear, but when the charged toner adhering to the surface of the collecting roller 107 is scraped off by the removing blade 108, a peeling discharge occurs, and the high resistance layer constituting the surface of the collecting roller Alternatively, a negative polarity charge is applied to the insulating layer, or a negative polarity charge is applied to the surface of the recovery roller 107 due to toner adhesion, and the applied charge remains even if the removal blade 108 scrapes off the toner. Is thinking. Therefore, in this embodiment, a voltage higher than the voltage applied to the collection roller 107 is applied to the removal blade 108.

In this embodiment, as the intermediate transfer belt 70, a synthetic resin such as polyimide, polycarbonate, polyester, and polypropylene or various rubbers containing a suitable amount of a conductive agent such as carbon black is used. Those having a resistivity of 10 ⁶ to 10 ¹⁴ Ω · cm are used.

  Further, an intermediate transfer belt having elasticity (hereinafter, referred to as “elastic intermediate transfer belt” if necessary) can also be used. In this case, silicone rubber, NBR, H-NBR, CR, EPDM, urethane rubber, etc. are used as the main base material of the conductive elastic layer, and the material of the conductive protective layer is reduced frictional resistance, environment of electrical characteristics Is not particularly limited as long as it can achieve the purpose of improving the residual toner cleaning performance by reducing the surface roughness and the surface roughness, but is not limited to polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether A coating material obtained by dissolving and dispersing a fluorine resin polymer such as (PFA) or PVdF in an alcohol-soluble nylon-based, silicone resin-based, silane coupler, urethane resin-based emulsion or an organic solvent can be used. These protective layers can be provided by dip coating, spray coating, electrostatic coating, roll coating, or the like. Furthermore, by subjecting the protective layer to surface treatment or polishing, it is possible to improve mold release properties, conductivity, wear resistance, surface cleaning properties, and the like.

Next, the photoreceptors 1Y, 1M, 1C, and 1K used in the printer of this embodiment will be described in detail.
As the photoreceptor 1 used in the present embodiment, 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, Using an amorphous silicon photoconductor (hereinafter referred to as “a-Si photoconductor”) having a photoconductive layer made of amorphous silicon (a-Si) by a film forming method such as a photo CVD method or a plasma CVD method. Can do. 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 described above is, for example, as follows. FIG. 10 is a schematic configuration diagram for explaining a layer configuration. In the a-Si-based photoconductor 500 shown in FIG. 10A, a photoconductive layer 502 made of a-Si: H, X and having photoconductivity is provided on a support 501. An a-Si photoconductor 500 shown in FIG. 10B 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 the like. It is composed of An a-Si photoconductor 500 shown in FIG. 10C 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 the like. And an amorphous silicon-based charge injection blocking layer 504. In the a-Si type photoreceptor 500 shown in FIG. 10D, a photoconductive layer 502 is provided on a support 501. The photoconductive layer 502 includes a charge generation layer 505 made of a-Si: H, X and a charge transport layer 506, and an amorphous silicon-based surface layer 503 is provided thereon.

The support 501 of the a-Si photoconductor 500 described above 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, a surface of the side on which at least the photosensitive layer is formed of an electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide, or a synthetic resin film or sheet, glass, ceramic, etc. It is also possible to use a support obtained by conducting a conductive treatment.
The shape of the support 501 can be a smooth surface, a cylindrical or plate-like surface having an uneven surface, or an endless belt, and the thickness thereof is appropriately determined so that a desired photoreceptor for an image forming apparatus can be formed. However, 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 the support 501 can be sufficiently exhibited. However, the support 501 is usually set to 10 [μm] or more from the viewpoints of manufacturing and handling, mechanical strength, and the like.

The a-Si-based photoconductor 500 that can be used in this embodiment functions to prevent the injection of charges from the conductive support side between the conductive support 501 and the photoconductive layer 502 as necessary. It is more effective to provide an amorphous silicon-based charge injection blocking layer 504 (FIG. 10C). In other words, the amorphous silicon-based charge injection blocking layer 504 has a function of blocking charge injection from the support 501 side to the photoconductive layer 502 side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. It has a so-called polarity dependency that does not exhibit such a function when it is subjected to a charging process with the opposite polarity. In order to provide such a function, the amorphous silicon type charge injection blocking layer 504 contains a relatively large amount of atoms for controlling conductivity as compared with the photoconductive layer 502.
The layer thickness of the amorphous silicon based charge injection blocking layer 504 is preferably 0.1 to 5 [μm], more preferably 0.3 to 4 [μm] from the viewpoints of obtaining desired electrophotographic characteristics and economic effects. [mu] m], optimally 0.5 to 3 [[mu] m].

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

The charge transport layer 506 is a layer mainly having a function of transporting charges when the photoconductive layer 502 is functionally separated. The charge transport layer 506 includes at least a silicone atom, a carbon atom, and a fluorine atom as its constituent elements, and is formed of a-SiC (H, F, O) including a hydrogen atom and an oxygen atom as required. Photoconductive properties, particularly 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 506 is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. The charge transport layer 506 is preferably 5 to 50 [μm], more preferably Is preferably 10 to 40 [μm], and most preferably 20 to 30 [μm].

The charge generation layer 505 is a layer mainly having a function of generating charges when the photoconductive layer 502 is functionally separated. This charge generation layer 505 is composed of a-Si: H containing at least silicon atoms as components and substantially not containing carbon atoms, and if necessary containing hydrogen atoms, and has desired photoconductive properties, particularly charge generation. Characteristics and charge transport characteristics.
The layer thickness of the charge generation layer 505 is appropriately determined as desired from the viewpoints of obtaining desired electrophotographic characteristics and economic effects, and is preferably 0.5 to 15 [μm], more preferably 1 to 10 [μm]. μm] and optimally 1 to 5 [μm].

If necessary, the a-Si photosensitive member 500 used in the present embodiment can be further provided with a surface layer on the photoconductive layer 502 formed on the support 501 as described above. A silicon-based surface layer 503 is preferably formed. The amorphous silicon-based surface layer 503 has a free surface and is provided to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability.
The thickness of the amorphous silicon-based surface layer 503 is usually 0.01 to 3 [μm], preferably 0.05 to 2 [μm], and most preferably 0.1 to 1 [μm]. Is desirable. If the layer thickness is less than 0.01 [μm], the amorphous silicon surface layer 503 is lost due to wear or the like during use of the photosensitive member, and if it exceeds 3 [μm], electrons such as an increase in residual potential are generated. Deterioration of photographic characteristics is observed.

  The a-Si photosensitive member 500 has a high surface hardness, shows high sensitivity to long wavelength light such as a semiconductor laser (770 to 800 [nm]), and hardly deteriorates due to repeated use. Therefore, it is an electrophotographic photoreceptor suitable for use in a high-speed copying machine, a laser beam printer (LBP), or the like.

  Alternatively, an organic photoreceptor in which a photosensitive layer is provided on a conductive support, a filler is contained in the surface layer coated on the photosensitive layer, and the charge transport material is a cross-linked charge transport material may be used. Abrasion resistance can be improved by incorporating a particulate material in the surface layer of the organic photoreceptor and using a cross-linked charge transport material as the charge transport material.

  Examples of the surface layer of the photoreceptor include a polymer or copolymer of a compound selected from vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether. Moreover, as a filler contained in a surface layer, although an organic filler and an inorganic filler may be used, an inorganic filler is used especially preferable. Examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, and a-carbon powder. Inorganic filler materials include silica, tin oxide, zinc oxide, titanium oxide, alumina, and oxide. Metal oxides such as zirconium, indium oxide, antimony oxide, bismuth oxide, calcium oxide, tin oxide doped with antimony, tin-doped indium oxide, metal fluorides such as tin fluoride, calcium fluoride, aluminum fluoride, Examples thereof include potassium titanate and boron nitride. These fillers may be used alone or in combination of two or more. In order to improve dispersibility, these fillers may be surface treated with a surface treatment agent.

  As the conductive support, a metal such as aluminum or stainless steel, a cylindrical cylinder such as paper or plastic, or a film is used. An undercoat layer (adhesive layer) having a barrier function and an undercoat function can be provided on these supports. The undercoat layer is used to improve the adhesion of the photosensitive layer, improve coating properties, protect the support, cover defects on the support, improve charge injection from the support, and protect the electrical coating of the photosensitive layer. It is formed. Known materials for the undercoat layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, copolymer nylon, glue, gelatin, and the like. These are dissolved in a solvent suitable for each and coated on a support. The film thickness is about 0.2 to 2 [μm].

  Specific examples of the photosensitive layer include those having a laminated structure of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material, and a single layer containing a charge generation material and a charge transport material. There are things that consist of.

  Examples of charge generation materials include pyrylium, thiopyrylium dyes, phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine, quinocyanine, etc. Can be used.

  As the charge transport material, a cross-linked charge transport material is preferably used. Specifically, pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-9- Ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, triarylmethane compounds such as p-diethylaminobenzaldehyde-2-methylphenyl) -phenylmethane, 1,1-bis (4-N, N-diethylamino-2-methylphenyl) heptane, 1,1,2, 2-tetrakis (4-N, N-dimethylamino- - polyaryl alkanes such as methyl phenyl) ethane, and triaryl amines, or the like can be used.

  Further, a photosensitive layer may be provided in which a protective layer is provided on the outermost surface and a filler is added 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. Moreover, you may add a plasticizer and a leveling agent in a protective layer in embodiment.

Next, the toner suitably used for the printer of this embodiment will be described.
In this embodiment, spherical toner having a high roundness with a shape factor SF-1 of 100 to 150 is used. 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 photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. When the shape factor SF-1 exceeds 150, the transfer rate decreases, which is not preferable.

FIG. 11 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). A value obtained by dividing the square of the maximum length MXLNG of a shape formed by projecting a spherical substance (toner in the present embodiment) onto a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
In other words,
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
Is defined by
FIG. 12 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-2. As shown in FIG. 12, the shape factor SF-2 is a numerical value indicating the ratio of the unevenness of 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.
In other words,
SF-2 = {(PELI) ² / AREA} × (100 / 4π)
Is defined by
In addition, SF-2 in this embodiment uses Hitachi's FE-SEM (S-800), and randomly samples the toner image 100 times, and the image information is manufactured by Nicole via the interface. This was introduced into the image analysis device (LUSEX 3), analyzed, and calculated from the above equation.

  As shown in FIG. 13, the image carrier, which is an image carrier unit that supports the photosensitive member 1 as an image carrier and the cleaning device 20 integrally in a frame 83 and is detachable from the printer body. The unit 300 may be used. In FIG. 13, in addition to the photosensitive member 1 and the cleaning device 20, the charging roller 3 and the developing device 6 are integrally supported, but at least the photosensitive member 1 and the cleaning device 20 are integrally supported. Anything is acceptable.

  Next, another example in which the cleaning apparatus according to the present invention is applied to a color image forming apparatus will be described with reference to FIG.

FIG. 14 is a diagram showing an example in which the belt cleaning apparatus 100 according to the present invention is applied to a printer which is a so-called one-drum type full-color image forming apparatus.
In this printer, the photoconductor 1 is housed in a main body housing (not shown). Around the photoreceptor 1, there are a charging roller 3 as a charging means, and developing devices 6C, 6M, and 6Y corresponding to cyan (C), magenta (M), yellow (Y), and black (K), respectively. , 6K, an intermediate transfer unit 70 as an intermediate transfer unit, a belt cleaning device 100 as a cleaning unit, and the like. The printer also includes a paper feed cassette (not shown) that stores recording paper as a plurality of recording materials. The recording paper in the paper feeding cassette is adjusted by a pair of registration rollers (not shown) one by one by a paper feeding roller (not shown), and then sent to a secondary transfer region between the secondary transfer unit 77 and the intermediate transfer unit 70. It is.

  When image formation is performed in the printer of FIG. 14, first, the photosensitive member 1 is rotationally driven counterclockwise in the figure, and the intermediate transfer belt 70 of the intermediate transfer unit 70 is rotationally driven clockwise in the figure. Then, after uniformly charging the surface of the photoreceptor 1 with the charging roller 3, the surface of the photoreceptor 1 is irradiated with a laser beam 4 modulated with C image data, and the surface of the photoreceptor 1 is exposed 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 of the intermediate transfer unit 70. Thereafter, the transfer residual toner remaining on the surface of the photoreceptor 1 is removed by the belt cleaning device 100, and then the surface of the photoreceptor 1 is again uniformly charged by the charging roller 3. Next, the surface of the photoconductor 1 is irradiated with laser light 4 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 70 so as to overlap the C toner image that has already been primarily transferred onto the intermediate transfer belt 70 of the intermediate transfer portion 70. Thereafter, Y and K are similarly primary-transferred onto the intermediate transfer belt 70. In this way, the color toner images on the intermediate transfer belt 70 that are overlapped with each other are transferred onto the recording paper conveyed to the secondary transfer area by the secondary transfer unit 77. The recording paper on which the toner image has been transferred in this manner is conveyed to a fixing unit (not shown) by a paper conveying belt 81. In this fixing section, the recording paper is heated and pressurized to fix the toner image on the recording paper to the recording paper. The recording sheet after fixing is discharged onto a discharge tray (not shown). The transfer residual toner remaining on the surface of the intermediate transfer belt 70 is removed by the belt cleaning device 100.

  In the one-drum type full-color image forming apparatus shown in FIG. 14, the belt cleaning device 100 is used as a cleaning unit for cleaning the transfer residual toner remaining on the surface of the intermediate transfer belt 70. In addition, the transfer residual toner can be satisfactorily removed from the surface of the intermediate transfer belt. Even if most of the transfer residual toner becomes positive polarity or negative polarity due to environmental fluctuations, the transfer residual toner can be satisfactorily removed from the intermediate transfer belt 70.

  Further, as shown in FIG. 15, a cleaning unit that removes toner adhering to the paper transport belt 81 may be used in a cleaning device having the same configuration as the belt cleaning device 100. In the printer shown in FIG. 15, 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 a cleaning device having the same configuration as the belt cleaning device 100 described above as the cleaning means for the paper transport belt 81, the toner on the paper transport belt 81 having a mixture of positive and negative polarities is improved. Can be removed.

As described above, the printer according to the present embodiment transfers the toner image formed on the intermediate transfer belt 70 as the image carrier from the intermediate transfer belt 70 to the recording paper as the recording material. The following configuration is employed as a belt cleaning device 100 for cleaning the transfer residual toner remaining on the intermediate transfer belt 70 after transfer. That is, the intermediate transfer belt surface is cleaned by contacting the surface of the intermediate transfer belt 70 as a cleaning object that moves on the surface and blocking the toner on the surface of the intermediate transfer belt, and the surface of the intermediate transfer belt by the applied voltage. A conductive cleaning blade 101 that charges the upper toner to a predetermined polarity (a negative polarity that is the same as the normal charging polarity of the toner), and the intermediate transfer belt surface in contact with the intermediate transfer belt surface moving downstream of the cleaning blade 101. A cleaning brush 102 for cleaning the surface of the intermediate transfer belt by electrostatically adhering the negatively charged toner on the surface of the intermediate transfer belt to the brush portion by the applied voltage while moving the brush portion to Cleaning blade 101 and cleaning bra In the cleaning device having a cleaning case 103 that accommodates 102, the brush portion is attached to the brush portion while moving the brush portion so as to contact the surface of the intermediate transfer belt on the downstream side of the cleaning brush 102 in the moving direction of the surface of the intermediate transfer belt. A lubricant application brush 104 for applying the applied lubricant to the surface of the intermediate transfer belt is provided in the cleaning case 103. As described above, the lubricant applying brush 104 is disposed in the same cleaning case 103 separately from the cleaning brush 102, whereby the cleaning brush 202 is used as the lubricant applying brush as in the cleaning device shown in FIG. Compared to the case, the amount of lubricant adhering to the cleaning brush is reduced. As a result, the deterioration of the cleaning performance of the cleaning brush due to the adhesion of the lubricant to the cleaning brush is suppressed.
In particular, the belt cleaning apparatus 100 of the present embodiment electrostatically discharges negatively charged toner attached to the brush portion by an applied voltage while moving its surface so as to face the brush portion of the cleaning brush 102. By adhering to the surface of the roller itself, the collecting roller 107 as a collecting rotating body for collecting the toner from the cleaning brush 102 and the toner on the surface of the collecting roller are dammed by contacting the surface of the collecting roller 107 The lubricant application brush 104 is disposed so that the brush portion of the lubricant application brush 104 is in contact with the surface of the recovery roller 107. Thereby, the lubricant of the lubricant application brush 104 can be applied not only to the intermediate transfer belt 70 but also to the surface of the collection roller 107. As a result, it is possible to effectively prevent the removal blade 108 from coming into contact with the surface of the collection roller 107 with a simple configuration.

  In the above description, the cleaning device according to the present invention has been described by taking the belt cleaning device 100 that cleans the intermediate transfer belt 70 as an example, but the same effect can be obtained even when used as a cleaning device that cleans the photosensitive member. can get.

1Y, 1M, 1C, 1K photoreceptor 70 intermediate transfer belt 100, 200 belt cleaning device 101 cleaning blade 101a blade power source 102, 202 cleaning brush 102a brush power source 103 cleaning case 103a inlet seal 103b outlet seal 104 lubricant coating brush 105 , 205 Solid lubricant 105a Spring 107 Recovery roller 107a Recovery power supply 108 Removal blade 108a Power supply 300 Image carrier unit

JP 2002-202702 A JP-A-2005-321833

Claims (13)

The surface of the object to be cleaned contacts the surface of the object to be cleaned moving and stops the toner on the surface of the object to be cleaned to clean the surface of the object to be cleaned, and the applied voltage causes the toner on the surface of the object to be cleaned to have a predetermined polarity. A conductive cleaning blade for charging
Toner charged to the predetermined polarity on the surface of the object to be cleaned by the applied voltage while moving the brush portion in contact with the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned of the cleaning blade A cleaning brush for cleaning the surface of the object to be cleaned by electrostatically adhering to the brush portion;
In a cleaning device having the cleaning blade and a cleaning case for storing the cleaning brush,
Apply the lubricant adhering to the brush part to the surface of the object to be cleaned while moving the brush part in contact with the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned of the cleaning brush. A cleaning device, wherein a lubricant application brush is provided in the cleaning case. The cleaning device according to claim 1.
By moving the surface of the self so as to face the brush part of the cleaning brush, the toner charged to the predetermined polarity attached to the brush part by the applied voltage is electrostatically attached to the surface of the self. A collection rotating body for collecting toner from the cleaning brush;
A removal blade that removes toner from the surface of the recovery rotator by contacting the surface of the recovery rotator and blocking the toner on the surface of the recovery rotator;
A cleaning device, wherein the lubricant application brush is arranged so that a brush portion of the lubricant application brush contacts a surface of the recovery rotating body. In an image forming apparatus for forming an image on a recording material by finally transferring the toner image formed on the image bearing member onto the recording material from the image bearing member,
An image forming apparatus using the cleaning device according to claim 1 or 2 as a cleaning device for cleaning a transfer residual toner remaining on the image carrier after transfer. The image forming apparatus according to claim 3.
A plurality of developing devices each containing toner of different colors,
The plurality of developing devices are arranged opposite to the one image carrier, and toners of different colors are attached to the latent image on the image carrier by the plurality of developing devices. An image forming apparatus characterized by forming a toner image on a body. The image forming apparatus according to claim 3.
A plurality of developing devices each containing toner of different colors,
The number of the image carrier is the same as that of the plurality of developing devices,
One developing device is arranged opposite to each image carrier, and each color is adhered to each image carrier by attaching a different color toner to each latent image on each image carrier. An image forming apparatus comprising: forming a toner image; and superposing these toner images to finally form a toner image on a recording material. The image forming apparatus according to claim 4 or 5,
An image forming apparatus using a photoconductor made of a material in which a filler is dispersed as the image carrier. The image forming apparatus according to any one of claims 4 to 6,
An image forming apparatus using an organic photoreceptor having a surface layer reinforced with a filler as the image carrier. The image forming apparatus according to any one of claims 4 to 7,
An image forming apparatus comprising an organic photoreceptor using a cross-linked charge transport material as the image carrier. The image forming apparatus according to any one of claims 4 to 6,
An image forming apparatus comprising: a photosensitive member having a photosensitive layer made of amorphous silicon as the image carrier. The image forming apparatus according to claim 3.
An image forming apparatus, wherein a toner image formed on a latent image carrier is transferred to the image carrier and finally formed on a recording material. In an image forming apparatus for forming an image on a recording material by finally transferring the toner image formed on the image bearing member onto the recording material from the image bearing member,
Having a recording material conveying member that adsorbs and conveys the recording material to the surface;
An image forming apparatus using the cleaning device according to claim 1 or 2 as a cleaning device for cleaning toner adhering to the recording material conveying member. The image forming apparatus according to any one of claims 3 to 11,
An image forming apparatus using the toner having a shape factor SF1 of 100 or more and 150 or less. An image carrier and a cleaning device for cleaning transfer residual toner remaining on the image carrier after transfer are integrally supported, and a toner image formed on the image carrier is transferred onto the image carrier. In an image carrier unit that is detachable from an image forming apparatus that forms an image on the recording material by finally transferring the recording material onto the recording material,
An image carrier unit using the cleaning device according to claim 1 or 2 as the cleaning device.

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