JP2004093589A - Image forming method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of appropriately maintaining positional relation between an image carrier and an opposed member by removing a foreign matter adhering to the surface of a positioning member. <P>SOLUTION: The image forming apparatus is equipped with a cleaning means 200 abutting on the surface of a gap control member 25 provided on an electrifying roller 2 so as to clean the surface of the member 25. The surface of the member 25 is cleaned by the cleaning means 200. Thus, the value of a gap G between the surface of the electrifying roller 2 and the surface of a photoreceptor 1 is always maintained at an appropriate value, so that an abnormal image formed because the gap G becomes larger than the aimed one is prevented. By constituting the cleaning means 200 of a cleaning brush, contact pressure is weakened in comparison with the cleaning means constituted of a foaming elastic body, whereby there is no trouble that the member 25 is worn or peeled with the lapse of time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image by an electrophotographic process, such as a copying machine, a printer, and a facsimile. More specifically, a positioning member provided on at least one of the image carrier and the opposing member arranged to face the image carrier is rotatably abutted on the other surface to maintain the positional relationship between the image carrier and the opposing member. The present invention relates to an image forming apparatus having the following configuration.
[0002]
[Prior art]
Conventionally, as this type of image forming apparatus, there is known an image forming apparatus including a contact-type charging device that performs charging in a state where a charging member such as a charging roller is in contact with or close to the surface of an image carrier such as a photoconductor. ing. The resistance of the charging member in the contact-type charging device changes due to the adhesion of foreign matter to the surface over a long period of use. That is, foreign matters such as toner remaining on the image carrier and paper dust generated from the transfer paper pass through the photoconductor cleaning unit and gradually adhere to the surface of the charging member located downstream of the photoconductor cleaning unit. Further, paper dust, toner, dust, and the like floating in the image forming apparatus also gradually adhere to the charging member. The foreign matter attached to the charging member changes the resistance value of the charging member over a long period of use. For this reason, when the surface of the image carrier is charged by the contact type charging member, an abnormal image may be generated due to poor charging such as uneven charging and insufficient charging.
[0003]
As a method of removing such foreign matter adhering to the surface of the charging member, a method of pressing a pad-shaped cleaning pad against the surface of the charging member is known (Japanese Patent Laid-Open No. 8-123140). However, the cleaning pad is pressed against the surface of the charging member in a state where the foreign matter removed from the surface of the charging member is captured. For this reason, according to this method, when the foreign matter includes the toner and the additive, the toner and the additive are rubbed against the surface of the charging member. As a result, a minute film-like film may be formed on the charging member due to long-term use due to the action of pressing of the cleaning pad, frictional heat, and the like, which may impair the charging function of the charging member. In addition, since such a cleaning pad has a small contact area with the surface of the charging member that actually contributes to cleaning of foreign substances, it is difficult to maintain the cleaning effect for a long time. Here, if the cleaning pad is enlarged and the contact area with the charging member is set to be large, there is a problem that the apparatus becomes large.
[0004]
Therefore, the present applicant has proposed an image forming apparatus including a charging device that charges the surface of the image carrier by applying a charging voltage to a charging member that faces the surface of the image carrier in a non-contact manner ( JP-A-14-169327). In this image forming apparatus, a positioning member is provided at both ends of a charging member, and a surface of the positioning member is rotatably brought into contact with a surface of the image carrier, and a predetermined gap is provided between the image carrier and the charging member. Is formed. As described above, when a non-contact type charging device in which the charging member is opposed to the surface of the image carrier in a non-contact manner is used, it is possible to reduce the adhesion of foreign matter to the surface of the charging member as described above. it is conceivable that.
[0005]
[Problems to be solved by the invention]
However, as described above, even in an image forming apparatus using a non-contact type charging device in which a predetermined gap is formed between the image bearing member and the charging member by the positioning member, the image forming device is not charged due to poor charging. In some cases, an abnormal image is generated. This type of abnormal image is an abnormal image that is generated when the value of the gap between the image carrier and the charging member is out of order.
[0006]
Such an abnormal image may be generated due to a change in the gap between the image carrier and the charging member due to the deviation of the straightness of the charging roller as the charging member. Therefore, the straightness of the charging roller was examined. However, this abnormal image was not caused by the deviation of the straightness of the charging roller.
Such an abnormal image may also occur when the driving gear for driving the charging roller is clogged with foreign matter and the rotation center of the driving gear is displaced. Therefore, the drive gear of the charging roller was carefully cleaned to form an image, but the occurrence of the abnormal image was not eliminated.
[0007]
As described above, the abnormal image is unlikely to be caused by the deviation of the straightness of the charging roller or the clogging of the driving gear of the charging roller with the foreign matter.
Therefore, the present inventors conducted various inspections in order to determine the cause of the occurrence of the abnormal image. As a result, it was confirmed that foreign matter was adhered to the surface of the positioning member for forming the gap between the image carrier and the charging member. Then, when an image was formed by cleaning and removing foreign matter adhering to the surface of the positioning member, an abnormal image due to the deviation of the gap value did not occur.
[0008]
In addition, this inspection has clarified a mechanism by which foreign matter adheres to the surface of the positioning member to cause a deviation in the value of the gap. The foreign matter adhering to the surface of the positioning member was found to be mainly foreign matter such as toner and paper powder scattered and floating in the apparatus from the developing device or the like. Foreign matter adhering to the surface of the positioning member gradually accumulates without being removed by the cleaning member of the charging member. Foreign matter adhering and accumulating on the surface of the positioning member displaces the position of the surface of the positioning member. It has been clarified that the displacement of the position of the surface of the positioning member causes a deviation in the value of the gap between the image carrier and the charging member as described above.
[0009]
The deviation of the gap due to the adhesion of the foreign matter to the positioning member is not limited to the gap between the image carrier and the charging member. For example, the gap between the image carrier and the transfer member, and the gap between the image carrier and the developing member. Also occurs in gaps. Further, when positioning members are provided at both ends of the opposing member in order to form a predetermined nip width at a press contact portion between the image carrier and the opposing member made of an elastic body, foreign matter to the positioning member may be reduced. The adhesion causes a deviation in the nip width. As described above, in the image forming apparatus configured to maintain the positional relationship between the image carrier and the opposing member by using the positioning member, the gap and the nip width as described above are out of order due to the adhesion of the foreign matter to the positioning member. There is a problem that occurs.
[0010]
The present invention has been made in view of the above problems. It is an object of the present invention to provide an image forming apparatus capable of preventing occurrence of an abnormal image due to a misalignment of a positional relationship between an image carrier and an opposing member.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a positioning member provided on at least one of an image carrier or an opposing member arranged to face the image carrier is rotated in contact with the other surface, An image forming apparatus configured to maintain a predetermined positional relationship between the image carrier and the facing member, characterized in that the image forming apparatus includes a cleaning unit for cleaning at least a surface of the positioning member. It is.
According to a second aspect of the present invention, the image bearing member and the charging member are rotated by abutting and rotating a positioning member provided on at least one of the image bearing member and a charging member disposed to face the image bearing member against the other surface. Are configured to maintain a predetermined positional relationship, and after the surface of the image carrier is uniformly charged by a charging member, an electrostatic latent image is formed on the surface of the image carrier by exposure means. An image forming method for visualizing an electrostatic latent image on an image carrier with a developer supplied from a developing device, and transferring the visible image to a recording medium by a transfer unit to form an image on the recording medium Wherein the image forming is performed while the surface of the positioning member is cleaned by a cleaning unit.
According to a third aspect of the present invention, in the image forming apparatus of the first aspect, the cleaning means is constituted by a cleaning brush.
According to a fourth aspect of the present invention, in the image forming apparatus according to the first or third aspect, the opposed member is formed of a roller-shaped member, and the positioning member is provided at both ends of the opposed member. The cleaning member has a configuration capable of cleaning both surfaces of the positioning member and the facing member.
According to a fifth aspect of the present invention, in the image forming apparatus of the first, third or fourth aspect, the cleaning means is configured to abut against the surface to be cleaned by its own weight and to be driven to rotate by movement of the surface to be cleaned. It is characterized by the following.
According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, the moving speed of the portion of the cleaning unit in contact with the surface to be cleaned is set to a different moving speed from the moving speed of the surface to be cleaned. It is characterized by having.
According to a seventh aspect of the present invention, in the image forming apparatus of the third, fourth, fifth or sixth aspect, the cleaning brush has a length of 2 mm or less and a density of 20,000 brushes / cm. ² Characterized by the following:
According to an eighth aspect of the present invention, in the image forming apparatus of the third, fourth, fifth, sixth or seventh aspect, the cleaning brush has a base end portion of the brush fiber fixed to a roller-shaped core shaft by an electrostatic flocking method. It is characterized by comprising.
According to a ninth aspect of the present invention, in the image forming apparatus of the fourth, fifth, sixth, seventh, or eighth aspect, in the cleaning brush, a contact pressure of a portion in contact with a surface of the positioning member is in contact with a surface of the facing member. Characterized in that it is configured to be smaller than the contact pressure.
According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, by changing the flocking density of the brush fibers of the cleaning brush between a portion contacting the surface of the positioning member and a portion contacting the surface of the opposing member. , Wherein the contact pressure is set to a different value.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, or tenth aspect, the image forming apparatus is used as a developer for an image carried on the image carrier. It is characterized in that the toner is made by a polymerization method.
According to a twelfth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, or eleventh, at least the image bearing member, the facing member, and the cleaning unit are provided. Are configured by unitized process cartridges.
[0012]
In this image forming apparatus, at least the surface of the positioning member is cleaned by the cleaning unit. Thereby, for example, foreign matters such as toner and paper dust attached to the surface of the positioning member are removed, and the positional relationship between the image carrier and the facing member is maintained at the initial predetermined positional relationship. Become like
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a tandem-type color laser printer (hereinafter, simply referred to as a “printer”) that is an image forming apparatus will be described. FIG. 1 shows an example of a printer having a configuration common to each embodiment described later. This printer includes four sets of toner image forming units 101Y, 101M, 101C, and 101K for forming images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). Are arranged in order from the upstream side in the movement direction. Here, the suffixes Y, M, C, and K of the respective codes indicate members for yellow, magenta, cyan, and black, respectively. Each of the toner image forming units 101Y, 101M, 101C, and 101K includes a photosensitive unit having a photosensitive drum 1 as an image carrier and a developing unit as a developing device. The toner image forming units 101Y, 101M, 101C, and 101K are arranged at a predetermined pitch so that the rotation axis of the drum-shaped photoconductor 1 as an image carrier is parallel and in the transfer paper moving direction. And so on.
[0014]
This printer includes an optical writing unit 102 as latent image forming means, sheet cassettes 103 and 104, and a pair of registration rollers 105, in addition to the toner image forming units 101Y, 101M, 101C and 101K. The image forming apparatus further includes a transfer unit 108, a belt fixing type fixing unit 107, and a sheet discharge tray 106. Further, a manual tray (not shown), a toner supply container, a waste toner bottle, a duplex / reversing unit, and a power supply unit are also provided.
The optical writing unit 102 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and is configured to irradiate the surface of each photoconductor 1 with a laser beam while scanning based on image data. .
[0015]
FIG. 2 shows an enlarged schematic configuration of one of the toner image forming units 101Y, 101M, 101C, and 101K. Each of the toner image forming units 101Y, 101M, 101C, and 101K has the same configuration. In FIG. 2, the photoconductor 1 is driven to rotate in the direction of arrow A with the start of the image forming operation. As a result, as shown in FIG. 3, the rotation of the driven gear 2a, which engages with the driving gear 1b integrated with the flange 1a of the photosensitive member 1, causes the charging roller 2 disposed opposite to the surface of the photosensitive member 1 to rotate as indicated by an arrow B. Rotate in the direction.
[0016]
The charging roller 2 includes a cored bar 3 and an elastic body 4 fixed around the cored bar 3. When the charging roller 2 rotates as described above, a charging voltage of a predetermined polarity (here, -700 V) is applied to the core metal 3. As a result, the surface of the photoconductor 1 is charged to a predetermined polarity. An electrostatic latent image is formed on the charged surface of the photoconductor 1 by irradiating a light-modulated laser beam LB emitted from the optical writing unit 102. This electrostatic latent image is visualized as a toner image by the developing device 5. The illustrated developing device 5 has a developing case 6 containing a powdered developer D and a developing roller 7 that carries and transports the developer D, and is driven to rotate in the direction of arrow C. The toner in the developer carried on the peripheral surface of the developing roller 7 is electrostatically transferred to an electrostatic latent image formed on the photoconductor 1. Thus, the electrostatic latent image is visualized as a toner image.
[0017]
A transfer belt 8 driven in the direction of arrow E is disposed opposite to the photoreceptor 1. The transfer belt 8 carries and conveys the transfer paper P fed from the paper feed cassettes 103 and 104. The transfer paper P carried and conveyed by the transfer belt 8 is sent to a transfer area between the photoconductor 1 and the transfer belt 8. When passing through the transfer area, the toner image formed on the photoconductor 1 is transferred onto the transfer paper P by a transfer voltage applied to a transfer device 9 disposed opposite to the photoconductor 1 with the transfer belt 8 interposed therebetween. Is electrostatically transferred to Here, the toner image formed on the photoreceptor 1 may be primarily transferred onto an intermediate transfer member, and the primary transfer toner image may be secondarily transferred onto the transfer paper P.
[0018]
The transfer residual toner remaining on the surface of the photoconductor 1 after the transfer of the toner image is scraped off by the cleaning brush 10 and the cleaning blade 11 pressed against the surface of the photoconductor 1. On the other hand, the toner image transferred to the transfer paper P is fixed on the transfer paper P by the action of heat and pressure when passing through the fixing unit 107.
[0019]
In this printer, a photoconductor 1, a charging roller 2, a cleaning brush 10, and a brush roller 12, which will be described later, are rotatably assembled to a unit case 13. Further, the base end of the cleaning blade 11 is fixed to the unit case 13. These integrated units 14 are constituted by a process cartridge 100 as shown by a chain line in FIG. The process cartridge 100 can be pulled out to the near side of the printer main body along the guide rail 15 fixed to the printer main body. Further, the unit 14 can be loaded at a predetermined position by pushing the process cartridge 100 into the inner side of the printer body.
[0020]
The cleaning brush 10, the cleaning blade 11, and the cleaning case 16 integrated with the unit case 13 constitute a photoconductor cleaning device 17 for cleaning the surface of the photoconductor 1.
[0021]
As shown in FIG. 3, the charging roller 2 is arranged so as to face the photoconductor 1 and charges the surface of the photoconductor 1. The surface of the charging roller 2 is in a non-contact state with a predetermined gap G from the surface of the photoconductor 1 via a gap management member 25 as a positioning member for positioning the charging roller 2 with respect to the photoconductor 1. They face each other. As described above, by forming a predetermined gap G between the surface of the photoconductor 1 and the surface of the charging roller 2 by the gap management member 25, the transfer residual toner remaining on the surface of the photoconductor 1 is charged. Adhesion to the roller 2 can be prevented. This will be described with reference to a developed view shown in FIG. In FIG. 4, the image forming area on the surface of the photoconductor 1 is an area corresponding to the developing width L of the developing roller 7. The width of the transfer device 9 located downstream of the developing roller 7 in the moving direction of the photoconductor surface is set to be at least larger than the developing width L of the developing roller 7. Further, the width of the cleaning brush 10 for removing the transfer residual toner on the photoconductor 1 is also set to be at least larger than the developing width L of the developing roller 7. The width of the cleaning blade 11 disposed downstream of the cleaning brush 10 is set to be larger than the width of the cleaning brush 10 so that the transfer residual toner that cannot be completely removed by the cleaning brush 10 can be removed. . The width Y of the surface of the charging roller 2 is set to be substantially the same as the width of the cleaning brush 10. Further, the width of the cleaning blade 11 is set to be larger than the sum (W = Y + 2Z) of the width Y of the surface of the charging roller 2 and the width Z of each gap management member 25. As a result, the transfer residual toner remaining on the surface of the photoconductor 1 is removed by the cleaning brush 10 and further removed by the cleaning blade 11, thereby being almost completely removed from the surface of the photoconductor 1. In addition, in this printer, a predetermined gap G is formed between the surface of the photoconductor 1 and the surface of the charging roller 2 by the gap management member 25, so that the transfer residual toner is applied to the charging roller 2. Adhesion is suppressed.
[0022]
However, even when the non-contact type charging roller 2 having the gap G formed as described above is used, as described above, an abnormal image of a type that occurs when the value of the gap G is out of order may occur. was there. The deviation of the value of the gap G was found to be due to the fact that foreign matters such as toner and paper powder floating in the printer main body adhere to the surface of the gap management member 25 by the above-described inspection. The gap G between the surface of the charging roller 2 and the surface of the photoconductor 1 must be set to 50 μm or less, and it is known that an abnormal image due to a gap failure occurs if the gap G is larger than this. Therefore, the normal target value of the gap G is set to an intermediate value of about 25 μm. However, the value of the gap G varies in the range of 30 to 40 μm depending on the processing accuracy and straightness of the charging roller 2. For this reason, even if only a small-diameter toner having an average particle diameter of about 7.5 μm adheres to the surface of the gap management member 25, the influence on the gap G increases.
[0023]
Such a problem can be solved by using an image forming apparatus according to each embodiment described below. It should be noted that among the components of the image forming apparatus according to the following embodiments, those having the same configuration and function as those of the printer shown in FIGS. The same reference numerals are given to the same reference numerals, and the description is omitted.
[0024]
(Embodiment 1)
The image forming apparatus according to the first embodiment has the following features in addition to the configuration of the printer. FIG. 5 illustrates a schematic configuration of a main part of the image forming apparatus according to the first embodiment. As shown in FIG. 5, the image forming apparatus has a cleaning unit 200 that contacts the surface of the gap management member 25 provided on the charging roller 2 to clean the surface of the gap management member 25. are doing.
Here, as the gap management member 25, for example, a general-purpose member in which an adhesive layer is provided on a film made of polypropylene (PP) is preferably used in terms of cost. Further, the cost may be slightly higher in price, but the gap management member 25 may be formed of Teflon (registered trademark) material having low adhesion of foreign matter. Further, if only the gap G is formed between the surface of the charging roller 2 and the surface of the photoconductor 1, the gap management member 25 can be provided on the photoconductor 1 side. However, in this case, there is a difficulty in cleaning the surface of the photoconductor 1 by the cleaning blade 11.
On the other hand, the cleaning means 200 may be any device as long as it can clean the surface of the gap management member 25. However, when the gap management member 25 is formed of polypropylene, it is preferable to use a cleaning brush formed of brush fibers in order to reduce damage to the gap management member 25 during cleaning. With this cleaning brush, there is no fear of causing a problem on an image due to stick-slip, as compared with a cleaning unit made of a foamed elastic body. This makes it possible to keep the cleaning means in contact with the surface of the charging roller 2 at all times, thereby simplifying the apparatus and reducing costs. Further, since the cleaning brush can increase the cleaning area, the cleaning performance can be maintained for a long time.
[0025]
(Embodiment 2)
The image forming apparatus according to the second embodiment has the following features in addition to the configuration of the image forming apparatus according to the first embodiment. The surface of the charging roller 2 of the image forming apparatus according to the first embodiment is separated from the mirror surface of the photoconductor 1 by a gap G. However, since the separation distance of the gap G is very small as described above, the toner or paper dust attached on the photoconductor 1 may be electrically attracted to the surface of the charging roller 2. Therefore, it is desirable to clean the surface of the charging roller 2 as well as the surface of the gap management member 25.
FIG. 6 illustrates a schematic configuration of a main part of the image forming apparatus according to the second embodiment. As shown in FIGS. 6 and 7, the cleaning device 18 for the charging roller 2 of the image forming apparatus includes a brush roller having a width W capable of cleaning both the surface of the charging roller 2 and the surface of the gap management member 25. 12 are provided. The width W of the brush roller 12 has a length obtained by adding the width Y of the surface of the charging roller 2 and the width Z of the surface of the gap management member 25. The illustrated brush roller 12 is arranged in parallel with the charging roller 2. As shown in FIGS. 7 and 8, the brush roller 12 includes a core shaft 19 made of a rigid body such as a metal or a hard resin, and a number of brushes whose base ends are fixed to the peripheral surface of the core shaft 19. It has a cleaning brush 20 made of fiber. The cleaning brush 20 is provided over the entire circumference of the core shaft 19 in a range indicated by the width W. As shown in FIG. 6, the cleaning brush 20 having such a configuration comes into contact with the surface of the charging roller 2 and the surface of the gap management member 25, and removes foreign matter attached to each surface.
[0026]
(Embodiment 3)
The image forming apparatus according to the third embodiment has the following features in addition to the configuration of the image forming apparatus according to the first or second embodiment. The brush roller 12 in the image forming apparatus according to the third embodiment is configured to abut against the surface of the charging roller 2 or the gap management member 25, which is the surface to be cleaned, by its own weight. The brush roller 12 is arranged to rotate following the movement of the surface of the charging roller 2 or the gap management member 25 which is the surface to be cleaned.
The illustrated brush roller 12 is arranged such that the cleaning brush 20 abuts on the surface of the charging roller 2 by its own weight and rotates in the direction of arrow H following the movement of the surface of the charging roller 2. ing. Specifically, as shown in FIGS. 2 and 8, bearing members 21 are fixed to the rear side plate 13A and the front side plate (not shown) of the unit case 13 (see FIG. 7). Is also indicated by a chain line). Each of the bearing members 21 is formed with a guide slot 22 whose lower part is open. In each guide slot 22, both ends in the longitudinal direction of the core shaft 19 of the brush roller 12 are rotatable, and along the guide slot 22 in the direction of arrow F (the direction approaching or separating from the surface of the charging roller 2). It is slidably fitted. The width of each guide slot 22 is set slightly larger than the diameter of each end of the core shaft 19. As a result, both end portions of the core shaft 19 are fitted into the respective guide slots 22 without rattling.
Thus, the brush roller 12 is located in the upper region of the charging roller 2, and both ends of the core shaft 19 are slidably fitted in the guide slots 22. As a result, the cleaning brush 20 comes into contact with the surface of the charging roller 2 by the weight of the brush roller 12. In addition, since both ends of the core shaft 19 are rotatably fitted in the guide slots 22, the rotation of the charging roller 2 in the direction of arrow B causes the brush roller 12 to follow the movement of the surface of the charging roller 2. As a result, it is driven to rotate in the direction of arrow H. As the brush roller 12 rotates with the rotation of the charging roller 2, the foreign matter adhering to the surface of the charging roller 2 and the surface of the gap management member 25 is removed by the cleaning brush 20.
[0027]
(Embodiment 4)
The image forming apparatus according to the fourth embodiment has the following features in addition to the configuration of the image forming apparatus according to the third embodiment. In the brush roller 12 of the image forming apparatus according to the fourth embodiment, the moving speed of the cleaning brush 20 that is in contact with the surface of the charging roller 2 or the gap management member 25 is different from the moving speed of the charging roller 2. Is set to As described above, as a method of making the moving speed of the cleaning brush 20 of the brush roller 12 different from the moving speed of the charging roller 2, a method of forcibly driving the brush roller 12 by a driving means such as a gear or a motor is used. Can be.
[0028]
(Embodiment 5)
The image forming apparatus according to the fifth embodiment has the following features in addition to the configuration of the image forming apparatus according to the first, second, third, or fourth embodiment. In the brush roller 12 of the image forming apparatus according to the fifth embodiment, the length of the brush fiber of the cleaning brush 20 is 2 mm or less and the density is 20000 brushes / cm. ² Is set to By forming the cleaning brush 20 of the brush roller 12 using the brush fibers having such a length and density, the strength of the cleaning brush 20 is improved, and the habit and breakage of the brush fibers are reduced. Further, such a cleaning brush 20 can be formed relatively easily by fixing the base end portion of the brush fiber to the roller-shaped core shaft 19 by an electrostatic flocking method with an adhesive.
[0029]
(Embodiment 6)
The image forming apparatus according to the sixth embodiment has the following features in addition to the configuration of the image forming apparatus according to the first, second, third, fourth, or fifth embodiment. The amount of toner or paper dust adhering to the surface of the charging roller 2 and the amount of foreign matter or scattered toner adhering to the surface of the gap management member 25 are significantly larger than the amount adhering to the surface of the charging roller 2. Many. For this reason, when the brush roller 20 having a cleaning property capable of sufficiently cleaning the surface of the charging roller 2 is used, there is a concern that the surface of the gap management member 25 with a small amount of foreign matter attached will wear over time. In order to solve this problem, it is conceivable that the surface of the charging roller 2 and the surface of the gap management member 25 are cleaned by different cleaning means. However, if the surface of the charging roller 2 and the surface of the gap management member 25 are cleaned by separate cleaning means, a new problem arises in that the cost increases and the apparatus cannot be simplified or downsized.
Therefore, in the image forming apparatus according to the sixth embodiment, the length of the brush fiber of the cleaning brush is determined by the portion of one brush roller 12 that contacts the surface of the charging roller 2 and the portion that contacts the surface of the gap management member 25. Different. For example, as shown in FIG. 9, the length of the brush fiber of the cleaning brush 20b in the portion contacting the surface of the gap management member 25 is set in advance rather than the length of the brush fiber of the cleaning brush 20a in contact with the surface of the charging roller 2. Form short. As a result, the cleaning brush 20b does not contact the surface of the gap management member 25 more strongly than necessary, and wear of the surface of the gap management member 25 over time is suppressed.
The load on the gap management member 25 can also be reduced by reducing the flocking density of the brush fibers of the cleaning brush 20b at the portion in contact with the surface of the gap management member 25.
[0030]
As described above, in the image forming apparatus according to the first embodiment, the surface of the gap management member 25 is cleaned by the cleaning unit 200. As a result, the value of the gap G between the surface of the charging roller 2 and the surface of the photoconductor 1 is always maintained at an appropriate value, and an abnormal image generated due to the gap G becoming larger than intended. Can be prevented. Further, by forming the cleaning means 200 with a cleaning brush, the contact pressure can be reduced as compared with the case where the cleaning means 200 is made of a foamed elastic body, and there is no fear that the gap management member 25 is worn out or peeled off over time.
Further, in the image forming apparatus according to the second embodiment, the foreign matter adhering to the surface of the charging roller 2 and the surface of the gap management member 25 can be removed by the cleaning brush 20 of one brush roller 12. This makes it possible to provide an inexpensive cleaning unit that can appropriately maintain the value of the gap G.
Further, in the image forming apparatus according to the third embodiment, there is no need for a unit that regulates the amount of biting of the cleaning brush 20 into the surface of the charging roller 2 and the surface of the gap management member 25 and a driving unit that drives the brush roller 12. . Thus, the configuration of the cleaning device 18 can be simplified, and the cost can be reduced. In addition, since the cleaning brush 20 does not excessively hit the surface of the charging roller 2, wear on the surface of the charging roller 2 can be suppressed.
Further, in the image forming apparatus according to the fourth embodiment, since the moving speed of the cleaning brush 20 of the brush roller 12 is different from the moving speed of the charging roller 2, the ability of the cleaning brush 20 to scrape foreign substances is improved. You.
In the image forming apparatus according to the fifth embodiment, the length of the brush fiber of the cleaning brush 20 is 2 mm or less, and the density is 20,000 / cm. ² , The strength of the cleaning brush 20 is improved. Also, the habit and breakage of the brush fibers are reduced. Thereby, the elastic deformation of the brush fibers due to the cleaning brush 20 being pressed against the surface to be cleaned for a long time is small, and it is possible to prevent the cleaning performance from being lowered due to the fall of the brush fibers.
Further, in the image forming apparatus according to the sixth embodiment, the load on the gap management member 25 can be reduced by reducing the length of the brush fibers or the flocking density of the cleaning brush 20 that contacts the gap management member 25. As a result, the surface of the charging roller 2 can be cleaned so that it can be used for a long time, and the gap management member 25 can maintain the target gap G for a long time.
Further, in the image forming apparatus according to each of the above-described embodiments, by using a toner created by a so-called polymerization method as the toner contained in the developing device 5, toner adhesion to the surface of the charging roller 2 can be prevented. It can be further suppressed. As described above, the foreign matter adhering to the surface of the charging roller 2 includes the toner that has passed through the cleaning device 17 for the photoconductor. Since the toner prepared by the polymerization method has an extremely uniform charge-to-mass ratio for each particle, the transfer efficiency in the electrostatic transfer step can be extremely increased. Therefore, by using the toner produced by this polymerization method, the amount of toner input to the cleaning device 17 is smaller than that of the conventional toner. As a result, the amount of toner that passes through the cleaning device 17 and adheres to the surface of the charging roller 2 also decreases. At this time, by making the shape of the toner not a shape close to a true sphere but a distorted shape, the toner is easily scraped off by the cleaning device 17 for the photoconductor, and the amount of toner input to the cleaning device 17 Is further reduced.
Further, in the image forming apparatus according to each of the above embodiments, the charging roller 2 and the cleaning device 17 are configured as a process cartridge 100 as shown in FIG. The process cartridge 100 can greatly improve the life of the charging roller 2. As a result, unlike the conventional process cartridge, the life of the charging roller 2 does not shorten the life of the entire process cartridge, and good operability, which is an inherent advantage of the process cartridge, can be utilized.
[0031]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, there exists the outstanding effect that generation | occurrence | production of the abnormal image by the misalignment of the positional relationship between an image carrier and an opposing member can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram showing an enlarged schematic configuration of a toner image forming unit of the printer.
FIG. 3 is a schematic perspective view showing a photosensitive member and a charging roller of the printer.
FIG. 4 is a development view showing a development of a photoreceptor of the printer and an image forming device arranged around the photoreceptor.
FIG. 5 is a schematic configuration diagram of an image forming apparatus according to the first embodiment of the present invention.
FIG. 6 is a schematic configuration diagram of an image forming apparatus according to a second embodiment of the present invention.
FIG. 7 is a schematic side view of a brush roller of the image forming apparatus according to the second embodiment.
FIG. 8 is a schematic configuration diagram of an image forming apparatus according to a third embodiment of the present invention.
FIG. 9 is a schematic configuration diagram of an image forming apparatus according to a sixth embodiment of the present invention.
[Explanation of symbols]
1 Photoconductor
2 Charging roller
7 Developing roller
11 Cleaning blade
12 brush roller
15 Guide rail
20 Cleaning brush
22 Guide slot
25 Gap management members
100 process cartridge
101 Toner image forming unit
102 Optical writing unit
103, 104 paper cassette
105 Registration roller
106 Output tray
107 fixing unit
108 transfer unit
200 Cleaning means
G Gap between photoreceptor surface and charging roller surface

Claims (12)

A positioning member provided on at least one of the image carrier and the opposing member disposed to face the image carrier is rotatably abutted on the other surface, and the image carrier and the opposing member have a predetermined positional relationship. In an image forming apparatus configured to face while maintaining
An image forming apparatus comprising: a cleaning unit for cleaning at least a surface of the positioning member. By rotating a positioning member provided on at least one of the image carrier and the charging member disposed to face the image carrier against the other surface, the image carrier and the charging member are brought into a predetermined positional relationship. After the surface of the image carrier is uniformly charged by a charging member, an electrostatic latent image is formed on the surface of the image carrier by exposure means, and the electrostatic latent image is formed on the image carrier. An image forming method of forming a latent image into a visible image with a developer supplied from a developing device, and transferring the visible image to a recording medium by a transfer unit to form an image on the recording medium,
An image forming method, wherein an image is formed while cleaning the surface of the positioning member by a cleaning unit. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the cleaning unit includes a cleaning brush. The image forming apparatus according to claim 1, wherein
The facing member is configured by a roller-shaped member,
The positioning member has a configuration that is provided at both ends of the facing member and rotates in contact with the surface of the image carrier,
The image forming apparatus, wherein the cleaning member has a configuration capable of cleaning both surfaces of the positioning member and the facing member. The image forming apparatus according to claim 1, 3 or 4,
The image forming apparatus is characterized in that the cleaning means abuts on the surface to be cleaned by its own weight, and is rotated by the movement of the surface to be cleaned. The image forming apparatus according to claim 5,
An image forming apparatus, wherein the moving speed of the portion of the cleaning means in contact with the surface to be cleaned is set to a different moving speed from the moving speed of the surface to be cleaned. The image forming apparatus according to claim 3, 4, 5, or 6,
The image forming apparatus, wherein the cleaning brush is made of brush fibers having a length of 2 mm or less and a density of 20000 brushes / cm ² . The image forming apparatus according to claim 3, 4, 5, 6, or 7,
The image forming apparatus is characterized in that the cleaning brush is configured by fixing a base end of a brush fiber to a roller-shaped core shaft by an electrostatic flocking method. The image forming apparatus according to claim 4, 5, 6, 7, or 8,
The image forming apparatus according to claim 1, wherein the brush is configured such that a contact pressure of a portion contacting the surface of the positioning member is smaller than a contact pressure of a portion contacting the surface of the opposing member. The image forming apparatus according to claim 9,
The contact pressure is set to a different value by changing the flocking density of the brush fibers of the cleaning brush between a portion in contact with the surface of the positioning member and a portion in contact with the surface of the opposing member. Image forming apparatus. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10,
An image forming apparatus, wherein a toner used as a developer of an image carried on the image carrier is formed by a polymerization method. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11,
An image forming apparatus, wherein at least the image carrier, the opposing member and the cleaning unit are configured as a unitized process cartridge.

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