JP2009092783A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing adhesion of a discharge product onto a charging device and an image carrier. <P>SOLUTION: This device is equipped with an image carrier cleaning means for cleaning the surface of the image carrier in the contact state with the image carrier by being moved in a direction perpendicular to a moving direction of the image carrier. When operating a charging device cleaning means, the image carrier cleaning means moves the image carrier in a prescribed direction, and simultaneously cleans the surface of the image carrier by being moved in a direction perpendicular to the moving direction of the image carrier. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a printer that forms an image on a recording material, and in particular, discharge unevenness of a discharge electrode with respect to a photoreceptor used as an image carrier during image formation, and The present invention relates to a technique for eliminating image density unevenness caused by potential unevenness due to adhesion of discharge products to a photoreceptor.

  2. Description of the Related Art Conventionally, as an image forming apparatus, there is an image forming apparatus such as a so-called electrophotographic copying machine or printer that forms an image using electrophotographic technology. In such an electrophotographic image forming apparatus, a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) that is rotatable is disposed as an image carrier. Around the photosensitive drum, a charging device for charging the photosensitive drum to a predetermined potential and an exposure device for forming an electrostatic latent image on the surface of the charged photosensitive drum are arranged. Further, around the photosensitive drum, a developing device that develops the formed electrostatic latent image with toner, a transfer device that transfers the formed toner image onto a recording material such as paper, and the surface of the photosensitive drum after transfer. A cleaning device that removes residual toner.

  Among these, as a charging device, a scorotron charging device that charges a photosensitive drum in a non-contact manner is known.

  The scorotron charging device includes a shield case in which a portion facing the photosensitive drum is opened along the axial direction of the photosensitive drum, a discharge electrode (for example, a discharge wire) disposed in the opening of the shield case, and a shield. And a grid electrode disposed facing the opening of the case.

  In the scorotron charging device, a DC voltage or a high voltage obtained by superimposing an AC voltage on the discharge wire is applied to the discharge wire, thereby ionizing the air around the discharge wire into an ion state.

  Then, the ionized charged particles move toward the opening side of the shield case. At that time, kinetic energy is given to other gas molecules, and an ion wind in the blowing direction is generated from the opening of the shield case.

  Then, with the generated ion wind, the charged particles pass through the holes of the grid provided on the opening side of the shield case to charge the photosensitive drum.

  In an image forming apparatus using an electrophotographic method, a photosensitive member, to which a conductive substrate is grounded, is uniformly charged using a charging device, and image exposure is performed using an exposure device. A latent image is formed.

  By the way, recent image forming apparatuses tend to increase the amount of power supplied to the discharge wire as the speed and image quality increase.

  This is because it is necessary to set the photosensitive drum to a predetermined charging potential in a shorter time than in the past by increasing the moving speed of the photosensitive drum.

  As a result of increasing the amount of electric power supplied to the discharge wire, the generation amount of discharge products (for example, ozone, NOx, etc.) increases, and the ion wind also becomes strong. For this reason, there is a problem that the generated discharge product adheres to the surface of the charging device or the photosensitive drum, causing discharge unevenness and potential unevenness formed on the photosensitive drum, thereby deteriorating the image.

  Therefore, as shown in FIG. 8, in order to prevent the adhesion of the discharge product attached to the discharge electrode 72, the discharge product is brought into contact with the discharge electrode 72 and automatically reciprocated along the discharge electrode 72. A technique for removing the light is proposed (see Patent Document 1).

  That is, in Patent Document 1, the charging device 7 is of a scorotron type, and includes a shield case 71 having an opening toward the photosensitive member, a sawtooth electrode 72 that generates corona discharge, and a grid (not shown). Yes. Further, the charging device 7 includes a cleaning member 73, a cleaning holding member 74 that holds the cleaning member 73, and a moving unit 75 that moves the cleaning holding member 74 along the longitudinal direction of the sawtooth electrode 72. The thin plate-like cleaning member 73 is pressed against the sawtooth electrode 72 and moved in the longitudinal direction to remove the discharge product.

  Further, as shown in FIG. 9, a technique for preventing an abnormal image caused by a discharge product of the charging device 7 by always contacting the surface of the photoreceptor 1 and cleaning the surface of the photoreceptor 1 has been proposed (see FIG. 9). Patent Document 2).

  That is, in Patent Document 2, a sheet-like product removing member 81 that contacts the surface of the photoreceptor 1 is provided on the downstream side of the cleaning device 12 in the rotation direction of the photoreceptor 1, and the product removing member 81 is supplied. It is fed out from the roller 82 and brought into contact with the surface of the photoreceptor 1 to remove the discharge product. Thereafter, the product removing member 81 is wound up by a winding roller 83.

  Further, in the technique shown in FIG. 10, a technique has been proposed in which a cleaning unit for cleaning the photosensitive member 1 is always brought into contact with the photosensitive member 1 and the cleaning ability of the cleaning unit is maintained (see Patent Document 3). .

That is, the first removal member 91 for removing the discharge product and the first removal member 91 in contact with the first removal member 91 at the post-transfer position in the moving direction of the photosensitive member 1, that is, downstream of the cleaning device 12. 2 removal member 92. The first removal member 91 is a brush roller using rayon fibers, and scrapes the discharge product by the mechanical rubbing action of the brush. The second removal member 92 is a brush roller made of zeolite material, and removes discharge products accumulated in the first removal member 91.
Japanese Patent Laid-Open No. 2005-84211 JP 2002-244520 A JP 2004-45446 A

  However, in the technique described in Patent Document 1, it is possible to maintain the discharge stability of the discharge electrode by cleaning the discharge electrode of the charging device. However, the discharge product generated by the discharge is However, since it adheres not only to the discharge electrode of the charging device but also to the surface of the photoreceptor, it is not a sufficient solution.

  Further, in the techniques of Patent Documents 2 and 3, it is possible to remove the discharge products adhering to the surface of the photoconductor by always contacting and cleaning the surface of the photoconductor during image formation.

  However, when this structure is used, as shown in FIG. 9, the apparatus of the cleaning means becomes large. Further, a member containing abrasive particles in the cleaning means performs unnecessary scrubbing even during image formation, thereby polishing the surface of the photoreceptor more than necessary and causing the life to be significantly reduced.

  Furthermore, as shown in FIG. 10, a mechanism such as a second removal member is required to further clean the surface of the first removal member, and there is a problem that the apparatus is enlarged as in the technique of FIG. 9.

  As a result of intensive studies based on the technical problems described above, the present inventor has focused on the fact that the charging high voltage is OFF when the discharge electrode cleaning of the charging device is performed. That is, it was found that the surface of the photosensitive member can be maintained over a long period of time without unnecessarily polishing the surface of the photosensitive member by performing timely cleaning of the surface of the photosensitive member at this timing.

  The present invention has been made based on such novel knowledge of the present inventors.

  That is, an object of the present invention is to solve the above technical problem, and to provide an image forming apparatus capable of suppressing adhesion of discharge products to a charging device and an image carrier. .

  Another object of the present invention is to maintain the stability of the potential and good image quality over a long period of time without unnecessarily polishing the surface layer of the image carrier by cleaning the surface of the image carrier at an appropriate time. An object of the present invention is to provide an image forming apparatus capable of performing the above.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention relates to a corona charging method charging device for charging an image carrier, and a discharge electrode of the charging device, and moves in a direction perpendicular to the moving direction of the image carrier to cause the discharge. In the image forming apparatus having the charging device cleaning means for cleaning the electrode,
It has an image carrier cleaning means provided with an image carrier cleaning member that contacts the image carrier and moves in a direction different from the moving direction of the image carrier to clean the surface of the image carrier. ,
The image carrier cleaning means moves the image carrier cleaning member in a direction different from the moving direction of the image carrier while moving the image carrier when the charging device cleaning means is operated. Clean the surface of the body,
An image forming apparatus characterized by the above.

  According to the present invention, it is possible to perform cleaning control for maintaining the surface property of the image carrier at the timing of cleaning the discharge electrode of the charging device, and to prevent discharge unevenness and image flow. .

  In other words, according to the present invention, in the electrophotographic image forming apparatus such as a copying machine or a printer, the surfaces of the image carrier and the charging device are cleaned in a timely manner during non-image formation. As a result, adhesion of discharge products on the charging device and the image carrier is reduced, and image formation without image flow is enabled.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

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

(Configuration of image forming apparatus)
In this embodiment, the image forming apparatus 100 is an electrophotographic color image forming apparatus. The image forming apparatus 100 includes a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 as an image carrier, and a charging device 7 as a charging unit disposed around the photosensitive drum 1. , An exposure device 8 as an exposure unit and a development device 13 as a development unit are provided. In this embodiment, the photosensitive drum 1 is provided with amorphous silicon (a-Si) as a photosensitive layer on a conductive substrate and has a diameter of 108 mm. Of course, it is not limited to this.

  In this embodiment, the developing device 13 includes a rotating developing device 13a in which three developing devices, that is, a yellow developing device 13Y, a magenta developing device 13M, and a cyan developing device 13C are mounted on a rotating member 14 that is rotationally driven. The black developing device 13K is a fixed developing device 13b.

  In the image forming apparatus configured as described above, the photosensitive drum 1 is driven to rotate in the direction of arrow A. The photosensitive drum 1 is charged to a predetermined potential by a charging device 7, and the charged photosensitive drum 1 is irradiated with laser light corresponding to image information by a laser exposure device 8 serving as an exposure device. An electrostatic latent image is formed on the drum 1.

  The electrostatic latent image on the photoconductive drum 1 is developed by a developing device containing each color component toner, and a visible image, that is, a toner image is formed on the photoconductive drum 1.

  An intermediate transfer belt 10 as an intermediate transfer member is disposed below the photosensitive drum 1, and each color component toner image formed on the photosensitive drum 1 is transferred by a primary transfer device 30 in the primary transfer portion T1. Sequential transfer (primary transfer) is performed.

  The superimposed image transferred to the intermediate transfer belt 10 is collectively transferred (secondary transfer) to the paper P as a recording material by the secondary transfer device 21 in the secondary transfer portion T2.

  The second-transferred image on the paper P is fixed on the paper P by the fixing device 5.

  On the other hand, the residue including the transfer residual toner on the photosensitive drum 1 after the primary transfer is removed by a drum cleaner 12 as a cleaning unit disposed around the photosensitive drum 1. Thereafter, the photosensitive drum 1 is charged again by the charging device 7, and the above-described image forming operation is repeated.

  In this embodiment, as the charging device 7, a corona charging method, that is, a non-contact charging type scorotron charging device is used. Of course, a corotron charging device can also be used as the charging device 7. In this embodiment, a surface cleaning unit (that is, an image carrier cleaning unit) 50 of the photosensitive drum 1 is provided between the charging device 7 of the scorotron type and the cleaning unit 12. The charging device 7 is provided with a charging device cleaning means 40 (see FIG. 2) for cleaning the discharge electrode 72 of the charging device 7. Details of the charging device 7, the charging device cleaning means 40, and the image carrier cleaning means 50 will be described later.

  Here, the intermediate transfer belt 10 will be described.

  In this embodiment, a plurality of intermediate transfer belts 10, which are four support rolls 17, 18, 19, 20 in this embodiment, are circulated and moved in the direction of the arrow. The support roll 17 is a drive roll for the intermediate transfer belt 10, the support rolls 18 and 20 are arranged as driven rolls, and the support roll 19 is used as a backup roll for the secondary transfer device 21.

  Further, a belt cleaner 22 for removing residues on the intermediate transfer belt 10 after the secondary transfer is disposed at a position of the intermediate transfer belt 10 with the drive roll 17 interposed therebetween.

The intermediate transfer belt 10 is made of a resin such as polyimide, polyamide, polyester, polypropylene, polyethylene terephthalate, or various rubbers containing an appropriate amount of a conductive agent such as carbon black. The volume resistivity is 10 ⁵ to 10 ¹⁵ Ωcm and the thickness is set to 0.1 mm.

  As described above, the secondary transfer portion T2 is disposed on the back surface side of the intermediate transfer belt 10 and the secondary transfer roll 21 as a secondary transfer device that is disposed in pressure contact with the toner image carrying surface side of the intermediate transfer belt 10. And a backup roll 19 serving as a counter electrode of the secondary transfer roll 21. The backup roll 19 is provided with a power supply means (not shown) for applying a secondary transfer bias having the same polarity as the charging polarity of the toner.

  Here, as the backup roll 19, an EPDM rubber having a two-layer structure in which the outer periphery of the metal core material is coated with a foamed elastic layer on the inside and a conductive layer on the outside is used. The outer conductive layer is a semiconductive EPDM foam rubber in which 15 to 35% by weight of carbon black is dispersed. The thickness of the conductive layer is 0.5 to 1.5 mm, and the surface resistivity is 7 to 10Ω. It is controlled to the resistance region of / □.

Further, the secondary transfer roll 21 is a coating made of a fluororesin material having a thickness of 5 to 20 μm on a core layer made of a metal core material and a carbon black dispersed foam EPDM material fixed around the metal core material through a skin layer. What formed the layer was used. The volume resistivity between the metal core and the coating layer is 10 ⁴ to 10 ⁵ Ωcm.

  Further, the paper transport system transports the paper P stacked on the paper tray 23 by the paper feed roll 24 and the transport roll 26, and then temporarily stops by the registration roll (registration roll) 25. Thereafter, the secondary transfer device 21 is sent to the position of the secondary transfer portion T2 where the secondary transfer device 21 is disposed at a predetermined timing. Further, the sheet P after the secondary transfer is conveyed to the fixing device 5 and discharged from the fixing device 5 to the outside of the apparatus.

  Next, the image forming process of this image forming apparatus will be described in more detail.

  Now, when a start switch (not shown) is turned on, a predetermined image forming process is executed.

  More specifically, for example, when the image forming apparatus of this embodiment is configured as a digital color copying machine, a document set on a document table (not shown) is read by a color image reading device. The read signal is converted into a digital image signal by a processing circuit and temporarily stored in a memory. Based on the stored digital image signals of four colors (Y, M, C, K), the toner images of the respective colors. Form.

  That is, the photosensitive drum 1, the charging device 7, the exposure device 8, and the developing device 13 (that is, the yellow developing device 13Y, the magenta developing device 13M, the cyan developing device 13C, and the black developing device) according to the digital image signal of each color. 13K) respectively.

  That is, the photosensitive drum 1 uniformly charged by the charging device 7 is irradiated with laser light by the laser exposure device 8 to write an electrostatic latent image corresponding to the digital image signal.

  Then, the electrostatic latent image formed on the photosensitive drum 1 is developed by the developing device 13 to form toner images of each color.

  In the case where the image forming apparatus 100 is configured as a printer, toner images of each color may be formed based on a digital image signal input from the outside.

  Each toner image formed on the photosensitive drum 1 is transferred from the photosensitive drum 1 to the surface of the intermediate transfer belt 10 by the primary transfer roll 30 at a primary transfer position T1 where the photosensitive drum 1 and the intermediate transfer belt 10 are in contact with each other. Are sequentially transferred.

  On the other hand, the toner remaining on the photosensitive drum 1 after the transfer is cleaned by the drum cleaner 12.

  The toner image primarily transferred to the intermediate transfer belt 10 in this way is superimposed on the intermediate transfer belt 10 and conveyed to the secondary transfer position T2 as the intermediate transfer belt 10 rotates. On the other hand, the paper P is transported to the secondary transfer position at a predetermined timing, and the secondary transfer roll 21 sandwiches and transports the paper P to the backup roll 19.

  At the secondary transfer position T2, the toner image carried on the intermediate transfer belt 10 is secondarily transferred to the paper P by the action of a transfer electric field formed between the secondary transfer roll 21 and the backup roll 19. The

  The paper P to which the toner image has been transferred is conveyed to the fixing device 5, and after the toner image on the paper P is heated and pressurized and fixed in the fixing device 5, a paper discharge tray (not shown) provided outside the apparatus. Are discharged. On the other hand, the toner remaining on the intermediate transfer belt 10 after the transfer is cleaned by the belt cleaner 22.

  Next, the above-described charging device 7, charging device cleaning means 40 and image carrier cleaning means 50 will be described in detail.

(Charging device and charging device cleaning means)
FIG. 2A is a perspective view showing a schematic configuration of the charging device 7 and shows the charging device cleaning means 40 with the shield plate on one side of the shield case removed. FIG. 2B is a schematic diagram of the central cross section of the charging device 7.

  The charging device 7 is disposed along the axial direction of the photosensitive drum 1 and is provided with charger blocks provided at both ends in the longitudinal direction, that is, support members 60 (60a, 60b) and both support members 60 (60a, 60b). ). The support frame 62 is provided with shield plates 71 a and 71 b constituting the shield case 71 along the axial direction of the photosensitive drum 1, that is, along the longitudinal direction of the charging device 7. In the present embodiment, another shield plate 71c is disposed between the shield plates 71a and 71b. Accordingly, two front openings 76 (76a, 76b) are formed at a portion facing the photosensitive drum 1.

  In the present embodiment, in the shield case 71 of the charging device 7, there are discharge electrodes between the shield plates 71 a and 71 c and between the shield plates 71 b and 71 c, and in the present embodiment, discharge wires (charge wires). 72 is stretched. Of course, a sawtooth electrode can also be used as the discharge electrode. A grid electrode 77 is disposed on the front opening 76 (76 a, 76 b) side of the shield case 71 so as to face the photosensitive drum 1.

  Here, the height (H) of the shield case 71 is 24 mm, the width (inner surface) (W) between the shield plates is 28 mm, and the distance (H0) from the opening 76 (76a, 76b) to the discharge wire 72. ) Is 8.0 mm.

  The discharge wire 72 is connected to a high voltage power source (not shown) for applying a DC high voltage, and the shield case 71 and the grid electrode 77 are provided with a varistor or the like for the purpose of holding them at a constant potential. A constant voltage element (not shown) is connected.

  The grid electrode 77 can be made of a metal mesh having a large number of air holes, and the aperture ratio is about 90%. Therefore, the grid electrode 77 does not hinder the air flow, and does not affect the air flow of the ion wind described later. As the grid electrode 77, in addition to a mesh-like one, for example, a plate material in which a large number of slits are formed can be used.

  Next, the charging device cleaning unit 40 will be described.

  In this embodiment, the charging device cleaning means 40 is a cleaning member 41 for cleaning the discharge electrode (discharge wire) 72 as shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b). And a holding member 42 for holding the cleaning member 41, and the holding member 42 is attached to the moving means 43.

  In the present embodiment, the moving means 43 is arranged on the back side of the shield case 71 opposite to the opening 76 (76a, 76b).

  The moving means 43 is a feed screw mechanism, and a feed screw (screw shaft member) 44 disposed along the longitudinal direction of the discharge wire 72 of the charging device 7, that is, along the rotational axis direction of the photosensitive drum 1. And a nut member 45 screwed into the screw shaft member 44. In this embodiment, a cleaning member holding member 42 is attached to the nut member 45.

  Accordingly, by rotating the screw shaft member 44 in the forward direction and the reverse direction for a predetermined time, the nut member 45 (that is, the cleaning member 41) is moved along the axial direction of the photosensitive drum 1, that is, the photosensitive drum 1. It is the structure which can be reciprocated in the direction orthogonal to the moving direction.

  More specifically, a drive mechanism (drive source) 61 is disposed at the end of the screw shaft member 44. The screw shaft member 44 is connected to the drive mechanism 61 at one end, and is driven and input via a gear train of the drive mechanism 61. Therefore, the screw shaft member 44 is configured to be rotationally driven by the drive mechanism 61.

  The nut member 45 is connected to an arm member (ie, a holding member) 42 to which the cleaning member 41 is attached. Therefore, when the drive mechanism 61 is driven, the screw shaft member 44 rotates around the longitudinal axis, and the nut member 45 screwed into the screw shaft member 44 thereby moves along the longitudinal axis of the screw shaft member 44. Moving. By changing the rotation direction of the drive mechanism 61, the nut member 45, that is, the cleaning member 41 is moved from one end side to the other end side in the longitudinal direction of the charging device 7, and from the other end side to the one end side. Can reciprocate. Of course, although not shown, a guide member for the nut member 45 is appropriately disposed so that the nut member 45 itself does not rotate.

  As understood with reference to FIGS. 3A and 3B, the cleaning member 41 includes a non-woven fabric 41b on the surface of the rubber member 41a, and is coated with abrasive particles 41c on the outermost layer and fixed with an adhesive. Have been made. The discharge wire 72 is sandwiched between such cleaning members 41 and 41. Accordingly, when the charging device cleaning unit 40 is moved by the moving unit 43 along the longitudinal direction of the discharge wire 72, the deposits attached to the surface of the discharge wire 72 are removed.

  The charging operation of the photosensitive drum 1 performed by the charging device 7 will be described.

  In FIG. 2B, when the photosensitive drum 1 starts rotating (moving) in the direction of the arrow in the figure, a DC voltage from a high voltage power source (not shown) is applied to the discharge wire 72, and around the discharge wire 72. Air is ionized and becomes an ionic state. Then, the ionized charged particles move toward the counter electrode side, that is, the photosensitive drum 1 side. At that time, kinetic energy is given to other gas molecules to generate an ion wind in this direction. The particles pass through the grid electrode 77 and charge the photosensitive drum 1. At this time, the grid electrode 77 is grounded via a constant voltage element (not shown) and is kept at a constant potential, and functions to make the surface potential of the charged photosensitive drum 1 uniform.

  Next, the surface cleaning means of the photosensitive drum 1 used in the present invention, that is, the image carrier cleaning means 50A will be described.

(Image carrier cleaning means)
FIG. 4A is a perspective view showing a schematic configuration of the charging device cleaning unit 40 and the image carrier cleaning unit 50A, and FIG. 4B shows the center of the charging device cleaning unit 40 and the image carrier cleaning unit 50A. It is the schematic of a cross section.

  As shown in FIGS. 4A and 4B, in this embodiment, the surface of the photosensitive drum 1 is cleaned upstream of the charging device 7 in the moving direction (arrow A direction) of the photosensitive drum 1. The image carrier cleaning means 50A is arranged.

  In this embodiment, as shown in FIGS. 4A and 4B, the image carrier cleaning means 50A uses an image carrier cleaning member 51A for cleaning the surface of the photosensitive drum, and this cleaning member 51A as a photosensitive member. Moving means 53 for driving in a direction different from the moving direction of the drum 1. In this embodiment, the cleaning member 51A is moved in a direction orthogonal to the rotation direction of the photosensitive drum 1 (that is, the rotation axis direction), but the present invention is not limited to this, and the rotation of the photosensitive drum 1 is not limited thereto. It may be slightly inclined with respect to the axis. In short, the cleaning member 51 </ b> A needs to be moved from one end to the other end over the entire width of the photosensitive drum 1 in the axial direction.

  In this embodiment, the cleaning member 51A is attached to the moving means 53 via a pressurizing member 52 such as a pressurizing spring.

  In this embodiment, the moving means 53 is the same mechanism as the charging device cleaning member moving means 43, and is a feed screw mechanism. In other words, the moving unit 53 includes a screw shaft member 54 installed along the axial direction of the photosensitive drum 1 and a nut member 55 that is screwed into the screw shaft member 54. The image carrier cleaning member 51A is configured such that the cleaning member 51A can reciprocate by rotating a feed screw (screw shaft member) 54 in a forward direction and a reverse direction for a predetermined time.

  More specifically, the drive from the drive mechanism (drive source) 61 is input to one end of the screw shaft member 54 via a drive gear mechanism (not shown). Therefore, the screw shaft member 54 is configured to be rotationally driven by the drive mechanism 61.

  Further, as described above, the nut member 55 is connected to the cleaning member 51A via the pressure member 52. When the drive mechanism 61 is driven, the screw shaft member 54 rotates around the longitudinal axis. Thereby, the nut member 55 screwed into the screw shaft member 54 moves along the longitudinal axis of the screw shaft member 54. By changing the rotation direction of the drive mechanism 61, the nut member 55, that is, the image carrier cleaning member 51 </ b> A, extends in the longitudinal direction of the charging device 7 from one end side to the other end side and from the other end side to the other end. Can be moved back and forth. Of course, although not shown, a guide member for the nut member 55 is appropriately arranged so that the nut member 55 itself does not rotate.

  As understood from the above, according to this embodiment, the image carrier cleaning member 51 </ b> A is also moved in the axial direction of the photosensitive drum 1 by the drive mechanism (drive source) 61 that moves the charging device cleaning unit 40. It is the composition to do.

  Further, the image carrier cleaning member 51A is a pad member, and is configured to be pressed against the photosensitive drum 1 by an elastic member 52 as a pressurizing unit. As an example of specific dimensions of the image carrier cleaning member 51A, the length W1 along the moving direction of the photosensitive drum 1 is 15 mm, the height H1 is 15 mm, and the length L1 in the axial direction of the photosensitive drum is 20 mm. It was. Of course, it is not limited to this.

  The pad-shaped cleaning member 51A of the photosensitive drum 1 includes a porous elastic body 51Aa such as a sponge as a support material, and abrasive particles 51Ab such as aluminum oxide are applied to the surface in contact with the photosensitive drum 1. Has been.

  In this embodiment, aluminum oxide particles # 2000 are applied. In the image forming apparatus 100 of the present embodiment, the amorphous silicon photoconductor is used as the photoconductor drum 1 as described above, and aluminum oxide is used as the abrasive particles because the surface is harder than OPC or the like.

  In particular, there is no problem in carrying out the present invention even if the abrasive particles are changed in accordance with the material of the photoreceptor to be used, and the abrasive particles are appropriately selected and adopted according to the material of the photoreceptor to be employed. obtain.

  Further, the support material 51Aa is not particularly limited as long as it can hold the abrasive particles 51Ab of the cleaning member 51A, and may not be a porous material, and may be provided with a nonwoven fabric or the like on the surface layer.

  In this embodiment, the cleaning member 51A that is a surface polishing member of the photosensitive drum 1 is retracted to a position that does not contact the surface of the photosensitive drum 1 (outside the end of the photosensitive drum 1) during image formation. (See FIG. 4 (a)). In the retracted position, the cleaning member 51A can be cleaned and / or the abrasive particles can be applied.

  When the surface of the photosensitive drum 1 is polished in synchronism with the timing of cleaning the discharge wire 72 of the charging device 7 when the charging device cleaning means 40 is operated, the charging device 7 moves to the image forming area of the photosensitive drum 1. It is the structure which contacts.

  The image forming apparatus 100 of the present embodiment is configured to clean the surface of the photosensitive drum at the timing when the main switch of the apparatus main body 100A is turned on or when a predetermined number of image formations are printed.

  Further, in the image forming apparatus 100 of this embodiment, the photosensitive drum 1 is rotated at the timing of cleaning the discharge wire 72 of the charging device 7, and the cleaning member 51A is brought into contact with the surface of the photosensitive drum while the photosensitive member 1 It is possible to clean the entire surface of the drum 1.

  As described above, the discharge wire 72 and the surface of the photosensitive drum 1 are cleaned as necessary at a predetermined timing. As a result, it is possible to suppress the occurrence of an abnormal image due to the discharge product adhering to the discharge wire 72 or adhering to the photosensitive drum, and to maintain high image quality over a long period of time.

Example 2
Next, a second embodiment of the image forming apparatus according to the present invention will be described. In the second embodiment, the configuration of the image forming apparatus 100, the configuration of the charging device 7, and the configuration of the charging device cleaning unit 40 are the same as those in the first embodiment. Therefore, the description of the first embodiment is used here. Will not be described again.

  As shown in FIGS. 5A and 5B, the present embodiment is different from the first embodiment in that the cleaning member 51B of the image carrier cleaning means 50B is a rotating body that rotates. In other words, in this embodiment, the cleaning member 51B includes a roller-shaped photoreceptor surface polishing member, and this polishing member rotates the photosensitive drum 1 while rotating the photosensitive drum 1 at the cleaning timing of the charging line. It is set as the structure which moves to the axial direction. This configuration is different from that of the first embodiment. Therefore, the image carrier cleaning means 50B having such a configuration will be described below.

  In this embodiment, as shown in FIGS. 5A and 5B, the image carrier cleaning means 50B includes a rotatable cylindrical surface scrutiny roller 51B. The roller 51B, as a photosensitive member surface polishing member, comes into contact with the photosensitive drum 1, and in a direction different from the rotation direction of the photosensitive drum 1 on the contact surface, that is, in this embodiment, the roller 51B. It is rotationally driven in a direction orthogonal to the moving direction.

  The image carrier cleaning unit 50B further includes the surface rubbing roller 51B that cleans the surface of the photoconductive drum, and a moving unit 53 that moves the rubbing roller 51B in the axial direction of the photoconductive drum 1. ,have.

  In this embodiment, the moving means 53 is the same mechanism as the charging device cleaning member moving means 43, and is a feed screw mechanism. That is, a support frame 55 that rotatably holds both ends of the rotation shaft 51Ba of the rubbing roller 51B is provided. The support frame 55 is screwed into a feed screw (screw shaft member) 54 provided in the axial direction of the photosensitive drum 1, and the screw shaft member 54 is predetermined according to the axial length of the photosensitive drum 1. The rubbing roller 51B is configured to reciprocate by rotating over time.

  More specifically, the moving means 53 is a nut member 55a constituted by a screw shaft member 54 installed along the longitudinal direction of the photosensitive drum 1 and a support frame body 55 screwed to the screw shaft member 54. And.

  The drive from the drive mechanism (drive source) 61 is input to one end of the screw shaft member 54 via a drive gear mechanism or the like. Therefore, the screw shaft member 54 is configured to be rotatable by the drive mechanism 61.

  Further, as described above, the support frame 55 constituting the nut member also constitutes the support leg member 55b that supports the rotation shaft of the roller 51B, and the leg portion 55b of the support frame 55 includes A rotation shaft 51Ba of the rubbing roller 51B is rotatably attached.

  Accordingly, when the drive mechanism 61 is driven, the screw shaft member 54 rotates around the longitudinal axis, and the nut member 55a screwed into the screw shaft member 54 thereby moves along the longitudinal axis of the screw shaft member 54. Moving. By changing the rotation direction of the drive mechanism 61, the nut member 55a, that is, the rubbing roller 51B, is moved from one end side to the other end side in the longitudinal direction of the charging device 7, and from the other end side to one end. Can be moved back and forth. Of course, although not shown, a guide member for the support frame 55 is appropriately disposed so that the support frame 55 itself does not rotate.

  In this embodiment, the rubbing roller 51B includes a gear 56 at one end of the rotation shaft 51Ba and meshes with a rack gear 57 disposed in the axial direction of the photosensitive drum 1. Accordingly, when the rubbing roller 51B reciprocates with respect to the photosensitive drum 1, the rubbing roller 51B rotates around the rotation shaft 52 of the rubbing roller 51B. The rotational driving of the rubbing roller 51B is not limited to this method. For example, the rubbing roller 51B itself can carry a drive motor or the like, and the rubbing roller 51B can be independently controlled to rotate. is there.

  By such rotation of the rubbing roller 51B and reciprocation in the axial direction of the photosensitive drum 1, the surface of the photosensitive drum 1 is polished, and surface cleaning is performed using the force of the rotational operation. .

  The rubbing roller 51B is retracted to a position where it does not come into contact with the photosensitive drum 1 during image formation, and moves in the axial direction of the photosensitive drum 1 only when the discharge wire 72 is cleaned. As a result, the surface is contacted with the photosensitive drum 1 to clean the surface.

  At this time, at a position where the rubbing roller 51B is retracted, as shown in FIG. 6, a member 58 that contacts the surface of the rubbing roller 51B is provided. In this embodiment, the member 58 has a brush configuration, and the surface thereof is coated with abrasive particles.

  When the photosensitive drum 1 is rotated during the operation of the charging device cleaning unit 40, the drive mechanism 61 is activated to start the movement of the rubbing roller 51 </ b> B along the axial direction of the photosensitive drum 1. As a result, during the image formation, the rubbing roller 51B in the retracted position rotates in contact with the particle applying member 58, and the abrasive particles are applied to the rubbing roller 51B and / or the rubbing roller 51B is cleaned.

  Further, when the rubbing roller 51B is provided with a drive motor or the like, the rotation of the rubbing roller 51B is started at the same time as the rotation of the photoconductor drum 1 is started when the surface of the photoconductor drum 1 is cleaned. Then, it is rotated in contact with the particle applying member 58. Thereafter, the rubbing roller 51 </ b> B may be moved in the axial direction of the photosensitive drum 1 to clean the surface of the photosensitive drum 1.

  By adopting such a configuration, it was possible to improve the surface polishing cleaning ability of the drum as compared with Example 1.

Example 3
Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. In the third embodiment, the image carrier cleaning means 50A of the first embodiment is further reduced in size.

  In the present embodiment, the configuration of the image forming apparatus 100, the configuration of the charging device 7, and the configuration of the charging device cleaning unit 40 are the same as those in the first embodiment. Therefore, the description of the first embodiment is used. The re-explanation here is omitted.

  In this embodiment, as in the first and second embodiments, the image carrier cleaning means 50C rotates the photosensitive drum 1 while the charging device cleaning means 40 reciprocates in the axial direction of the photosensitive drum. Clean the body drum surface at the same time. However, unlike the first and second embodiments, the grid electrode 77 is further cleaned simultaneously with the cleaning of the photosensitive drum 1.

  In the present embodiment, the image carrier cleaning means 50C includes an image carrier cleaning member 51C as in the first embodiment. Further, unlike the first and second embodiments, FIG. , (B), a grid electrode cleaning member 78 is provided. That is, in this embodiment, the image carrier cleaning member 51C and the grid electrode cleaning member 78 are configured to move between the surface of the photosensitive drum 1 and the grid electrode 77, and the surface of the photosensitive drum 1 and the grid electrode 77 are moved. And clean at the same time.

  The image carrier cleaning member 51C of this embodiment can use the same material as the image carrier cleaning member 51A described in the first embodiment. The grid electrode cleaning member 78 can use the same material as the discharge electrode cleaning member 41.

  Furthermore, the cleaning member for the grid electrode is not limited to the above. It can be changed according to the composition power of the opening of the grid electrode such as sponge member or brush member not coated with abrasive particles, so that the toner, fibrous fluff and dust attached to the grid electrode can be removed. You can do it.

  More specifically, as shown in FIGS. 7A and 7B, according to this embodiment, the image carrier cleaning means 50C is located between the surface of the photosensitive drum 1 and the grid electrode 77, and is flat. The support member 59 is provided. An image carrier cleaning member 51C is provided on the photosensitive drum side of the support member 59, and a grid electrode cleaning member 78 is provided on the grid electrode side. One end of the support member 59 is integrally attached to the moving means 53.

  In this embodiment, the moving means 53 is the same mechanism as the charging device cleaning member moving means 43, and is a feed screw mechanism. In other words, the moving unit 53 includes a screw shaft member 54 installed along the longitudinal direction of the photosensitive drum 1 and a nut member 55 that is screwed into the screw shaft member 54. One end of a support member 59 to which the cleaning members 51C and 78 are attached is attached to the nut member 55. Therefore, the cleaning members 51 </ b> C and 78 can reciprocate by rotating the screw shaft member 54 for a predetermined time according to the axial length of the photosensitive drum 1.

  Drive from the drive mechanism (drive source 61) is input to one end of the screw shaft member 54 via a drive gear mechanism or the like. Accordingly, the screw shaft member 54 can be driven to rotate by the drive mechanism 61.

  That is, when the drive mechanism 61 is driven, the screw shaft member 54 rotates around the longitudinal axis, and the nut member 55 screwed into the screw shaft member 54 moves along the longitudinal axis of the screw shaft. . By changing the rotation direction of the drive mechanism 61, the nut member 55, that is, the cleaning members 51C and 78, is arranged in the longitudinal direction of the charging device 7 from one end side to the other end side and from the other end side to the one end side. Can move back and forth. Of course, although not shown in the drawings, also in this embodiment, it is preferable to appropriately arrange a guide member for the nut member 55 in order to prevent the nut member 55 itself from rotating.

  Also in this embodiment, the cleaning member 51C that is a surface polishing member of the photosensitive drum 1 is retracted to a position that does not contact the surface of the photosensitive drum 1 (outside the end of the photosensitive drum 1) during image formation. (See FIG. 7B).

  When the surface of the photosensitive drum 1 is polished in synchronism with the timing of cleaning the discharge wire 72 of the charging device 7 when the charging device cleaning means 40 is operated, the charging device 7 moves to the image forming area of the photosensitive drum 1. It is the structure which contacts. In the retracted position, the cleaning member 51C can be cleaned and the abrasive particles can be applied.

  Using the configuration of the present embodiment, the grid electrode 77 and the surface of the photosensitive drum 1 can be cleaned at the same time during automatic cleaning of the charged lines.

  As described above, according to the present embodiment, the discharge electrode 72 of the charging device 7, the surface cleaning of the photosensitive drum 1, and the grid electrode 77 can also be cleaned. It became the composition which can maintain the quality of.

  In the above embodiments, the present invention has been described as an intermediate transfer type color image forming apparatus, but the present invention is not limited to this.

  In the present invention, for example, toner images formed on the surface of the photosensitive drum 1 are sequentially transferred directly to recording paper conveyed by a recording material carrier installed instead of the intermediate transfer belt. A direct transfer type color image forming apparatus in which a color image is recorded may be used.

  Further, the image carrier 1 that is a photosensitive drum does not need to be a photosensitive drum, and may be a belt-like photosensitive belt that is stretched around a support roller and is movable in a certain direction. .

  Of course, the image forming apparatus of the present invention is not limited to a color image forming apparatus, and may be a monochrome image forming apparatus.

  Since such an image forming apparatus is well known to those skilled in the art, further detailed description is omitted. The configuration of the present invention as described in the first, second, and third embodiments can be similarly applied to the image forming apparatus having such a configuration, and similar effects can be obtained.

1 is a schematic configuration diagram of an embodiment of an image forming apparatus according to the present invention. 2A is an exploded perspective view of a part of the charging device, and FIG. 2B is a central cross-sectional view of the charging device. FIG. 3A is a partial cross-sectional view of the discharge wire cleaning means, and FIG. 3B is a partial detail view of the cleaning member. FIG. 4A is a configuration diagram showing a schematic configuration of another embodiment of the charging device cleaning unit and the image carrier cleaning unit, and FIG. 4B is a cross-sectional view of the charging unit and the image carrier cleaning unit. FIG. FIG. 5A is a configuration diagram showing a schematic configuration of another embodiment of the charging device cleaning unit and the image carrier cleaning unit, and FIG. 5B is a cross-sectional view of the charging unit and the image carrier cleaning unit. FIG. FIG. 6 is a schematic configuration diagram for explaining a state in which the image carrier cleaning means shown in FIG. 5 is moved to a retracted position. FIG. 7A is a configuration diagram showing a schematic configuration of another embodiment of the charging device cleaning unit and the image carrier cleaning unit, and FIG. 7B is a side view of the charging unit and the image carrier cleaning unit. It is. It is a perspective view for demonstrating the discharge wire cleaning means provided in the conventional charging device. It is a schematic block diagram of the image forming apparatus for demonstrating an example of the conventional image carrier cleaning means. It is a schematic block diagram of the image forming apparatus for demonstrating the other example of the conventional image carrier cleaning means.

Explanation of symbols

1 Photosensitive drum (image carrier)
2 Intermediate transfer belt (intermediate transfer member)
5 Fixing device 7 Primary charger (charging device)
8 Exposure device 10 Transfer charger 12 Cleaner device 13 (13a, 13b) Developing device 21 Transfer roller (secondary transfer device)
30 Primary transfer roller (primary transfer device)
40 Charging device cleaning means 41 Cleaning member 42 Holding member 43 Moving means 44 Feed screw (screw shaft member)
45 Nut members 50A, 50B, 50C Image carrier cleaning means 51A, 51B, 51C Image carrier cleaning member 52 Pressure spring (pressure means)
53 Moving means 54 Feed screw (screw shaft member)
55 Nut member 56 Pinion gear 57 Rack gear 60 (60a, 60b) Charging block (support member)
61 Drive mechanism (drive source)
71 (71a, 71b, 71c) Shield plate (shield case)
72 Discharge wire (Discharge electrode)
77 Grid electrode 78 Grid electrode cleaning member

Claims (7)

A charging device of a corona charging method for charging the image carrier, and a charging device cleaning unit that contacts the discharge electrode of the charging device and moves in a direction perpendicular to the moving direction of the image carrier to clean the discharge electrode. And an image forming apparatus having
It has an image carrier cleaning means provided with an image carrier cleaning member that contacts the image carrier and moves in a direction different from the moving direction of the image carrier to clean the surface of the image carrier. ,
The image carrier cleaning means moves the image carrier cleaning member in a direction different from the moving direction of the image carrier while moving the image carrier when the charging device cleaning means is operated. Clean the surface of the body,
An image forming apparatus.   The image forming apparatus according to claim 1, wherein the image carrier cleaning unit includes a moving unit that holds and moves the image carrier cleaning member.   The image forming apparatus according to claim 2, wherein the moving unit moves the image carrier cleaning member in a direction orthogonal to a moving direction of the image carrier.   The image carrier cleaning member is a pad member pressed against the surface of the image carrier, and is made of an elastic body containing abrasive particles for polishing the surface of the image carrier. Item 4. The image forming apparatus according to any one of Items 1 to 3.   The image carrier cleaning member is a cylindrical rotating body that rotates in a direction different from the moving direction of the image carrier, and is made of an elastic body that includes abrasive particles that polish the surface of the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The charging device is a scorotron charging device,
The image carrier cleaning means includes a grid electrode cleaning member for cleaning the surface of the grid electrode of the charging device,
The image carrier cleaning means moves the image carrier cleaning member and the grid electrode cleaning member in a direction orthogonal to the moving direction of the image carrier while moving the image carrier during operation of the charging device cleaning means. To simultaneously clean the surface of the image carrier and the grid electrode,
The image forming apparatus according to claim 3.   The image carrier cleaning member is disposed at a retracted position that does not come into contact with the image carrier during image formation. At the retracted position, application of abrasive particles to the image carrier cleaning member and / or the image carrier is performed. The image forming apparatus according to claim 1, wherein the cleaning member is cleaned.

Images