JP4383198B2 - Scorotron charger cleaning structure - Google Patents

Description

  The present invention relates to a structure for cleaning a grid electrode of a scorotron charger provided to be slidable with respect to an image forming apparatus.

  In an electrophotographic image forming apparatus, a charging unit, an exposure unit, and a developing unit are provided around a photosensitive member. Then, after the photosensitive member is charged by the charging unit, exposure is performed by the exposing unit to form a latent image on the surface of the photosensitive member and developed by the developing unit. Thereafter, the developed toner image is transferred onto a transfer medium and further fixed to obtain a print image.

  In such an image forming apparatus, a scorotron charger is widely used as a charging means for uniformly charging the photosensitive member. In the scorotron charger, generally, a corona discharge wire is stretched in a shield housing, and a grid electrode for regulating and controlling a corona discharge current to the surface of the photoconductor is provided between the photoconductor and the corona discharge wire. A constant voltage is applied to the photoconductor by applying a high voltage to the corona discharge wire.

  Here, in the vicinity of the scorotron charger, ozone is generated by corona discharge, and an ion product is generated by the oxidizing action of ozone. The grid electrode is easily soiled by such ion products, scattered toner, paper powder, and the like. These deposits are generally insulators, and when such deposits adhere to the grid electrode, the charge on the photoreceptor becomes non-uniform, resulting in poor charging and uneven charging. Such uneven charging causes unevenness in the image and causes a reduction in image quality.

  Accordingly, it is necessary to periodically clean the surface of the grid electrode of the scorotron charger to remove ion products and toner. As a scorotron charger cleaning device, a scorotron charger cleaning member having a water-containing pad has been developed as described in Japanese Patent Application Laid-Open No. 09-249390.

  Here, the grid electrode is cleaned by the water-containing pad, but if the water content of the water-containing pad is too small, the water-soluble ion product attached to the grid electrode cannot be sufficiently dissolved, and the water-containing pad The cleaning effect by cannot be fully demonstrated. On the other hand, if the moisture content is too large, the remaining amount of moisture after cleaning increases, and dielectric breakdown occurs due to moisture remaining on the grid electrode, and corona discharge cannot be obtained.

Therefore, it is considered that the moisture content is preferably 6 to 40%, and the cleaning member of this scorotron charger is packed with a highly confidential aluminum bag in order to maintain the water content in the moisture pad during storage. It is designed to be removed from the aluminum bag when in use.
JP 09-249390 A

  However, even when the moisture content is maintained in the above-described preferable state, when cleaning is performed by bringing the moisture-containing pad into contact with the surface of the grid electrode, moisture is attached to the grid electrode and the holding portion of the grid electrode during and after the cleaning. A leak may occur between the corona discharge wire and the grid electrode. In particular, when the grid electrode surface of the charger of the image forming apparatus is arranged upward, for example, when the photosensitive drum as the charged body is arranged above the charger, the cleaning member is attached to the grid electrode. Since cleaning is performed by placing the liquid crystal on the upper side, the moisture adhering to the grid electrode and the holding portion of the grid electrode easily enters the charger due to the gravity, and therefore, leakage easily occurs.

  In addition, the scorotron charger needs to keep the distance between the grid electrode and the surface of the photoconductor constant in order to make the charging potential applied to the photoconductor constant. A gap roller that contacts the surface of the body is placed. The gap rollers are generally arranged so as to be exposed from openings provided at both ends of the grid electrode. For this reason, when cleaning is performed by bringing the hydrous pad into contact with the surface of the grid electrode, the hydrous pad and the gap roller come into contact with each other, whereby the hydrous pad is strongly compressed and moisture may flow out of the hydrous pad. This moisture may reach the vicinity of the discharge wire, and leakage may occur when a high voltage is applied to the discharge wire.

  An object of the present invention is to clean the toner and the like adhering to the grid electrode surface by bringing the water-containing member into contact with the surface of the grid electrode, and at the same time, suppressing the occurrence of leakage during corona discharge. There is to be able to do it.

The scorotron charger cleaning structure according to claim 1 is configured to clean a grid electrode of a scorotron charger that is disposed to face an image carrier in the image forming apparatus and is slidable with respect to an outlet of the image forming apparatus. a cleaning structure for, scorotron charger is provided at both ends of the shield casing, which gap roller is provided for defining the gap of the image bearing member and the grid electrode, a cleaning device having a water element And a protrusion provided at a position facing the gap roller of the shield housing side plate . The cleaning device includes a casing attached to the outlet of the image forming apparatus, and a water-containing member that is partly exposed from the opening of the casing and that can be brought into contact with the grid electrode of the scorotron charger when sliding with respect to the image forming apparatus. . The protrusion provided at the position facing the gap roller on the shield housing side plate of the scorotron charger is used to clean the grid electrode when the scorotron charger is slid and the water-containing member is slid onto the grid electrode. In the roller position, the water-containing member and the grid electrode are separated by contacting the casing .

When the scorotron charger is cleaned by a cleaning device having a water-containing member, the scorotron charger is slid out of the image forming apparatus and the water-containing pad is slidably contacted with the grid electrode to wipe off ion products and the like. . In that case, depending on the structure of the scorotron charger, there may be a portion that needs to avoid contact with the hydrous pad. In this cleaning structure, the protrusion gap roller position to avoid contact with the water-containing member provided in the scorotron charger, the hydrated member reaches the gap roller position protrusion is provided in the scorotron charger, the projections and the cleaning device By contacting, the cleaning device is separated from the scorotron charger. Therefore, the water-containing member does not come into contact with the scorotron charger at the portion where the protrusion is provided, and moisture contained in the water-containing member can be prevented from entering the charger from this portion.

  The cleaning structure of the scorotron charger according to claim 2 is the cleaning structure according to claim 1, wherein the cleaning device is disposed above the scorotron charger.

  When the grid electrode surface of the charger of the image forming apparatus is disposed upward and the cleaning member is disposed above the moisture, the water adhering to the grid electrode and the grid electrode holder easily enters the charger due to its gravity. .

  However, in this cleaning structure, as described above, when the water-containing member reaches a predetermined portion where the protrusion of the scorotron charger is provided, the cleaning device is separated from the scorotron charger, and the water-containing member is not provided in the portion where the protrusion is provided. No contact with the scorotron charger. For this reason, even when the water-containing member is disposed above the scorotron charger, it is possible to prevent moisture contained in the water-containing member from entering the charger.

  The scorotron charger cleaning structure according to claim 3 is the cleaning structure according to claim 1, wherein the scorotron charger has openings at both ends in the longitudinal direction of the grid electrode, and the protrusion is a scorotron charger. The water-containing member is provided so as to be separated from the scorotron charger at the opening.

  In the scorotron charger, a corona discharge wire is stretched in a generally U-shaped shield casing, and the grid electrode is disposed so as to cover the open end of the shield case. In order to stabilize the charging of the scorotron charger, it is necessary to keep the distance between the grid electrode and the member to be charged constant. Therefore, an opening is provided adjacent to both ends in the longitudinal direction of the grid electrode portion of the grid electrode plate, and a support member such as a gap roller is provided in the opening portion as a gap defining means for keeping the distance between the two constant. ing. When cleaning such a scorotron charger, if the water-containing member comes into contact with the opening, the moisture of the water-containing member may adhere to the opening and flow into the charger, and leakage may occur during corona discharge.

  Therefore, in the cleaning structure of the present invention, the scorotron charger is provided with a protrusion at the opening of the grid electrode so that the scorotron charger and the water-containing member can be separated from each other during cleaning by the cleaning device. Therefore, the water-containing member can be prevented from coming into contact with the opening of the grid electrode, and the inflow of moisture from the opening to the scorotron charger can be suppressed.

  The cleaning structure of the scorotron charger according to claim 4 is the structure according to any one of claims 1 to 3, wherein the cleaning device can come into contact with the protrusion of the scorotron charger on the end face of the opening side of the casing. Has protrusions.

  Here, by providing protrusions on the casing of the cleaning device, the protrusions provided on the cleaning device and the scorotron charger are provided in portions where it is necessary to avoid contact between the water-containing member of the cleaning device and the scorotron charger. The effect of separation can be increased by contact with the protruding portion.

A scorotron charger cleaning structure according to a fifth aspect of the present invention is the structure according to any one of the first to fourth aspects, further comprising a pressing member for pressing the scorotron charger toward the image carrier. Here, the pressing member includes a pressing spring provided in the case of the image forming apparatus, and a pressing link provided between the pressing spring and the scorotron charger.

Here, the gap roller is pressed against the surface of the photosensitive drum by the urging force of the pressing member, and the distance between the scorotron charger and the surface of the image carrier is kept constant. When the protrusion of the shield housing and the casing of the cleaning device come into contact with each other, the pressing spring that biases and supports the scorotron charger is compressed, and the scorotron charger can be pulled out of the image forming apparatus.

  The scorotron charger cleaning structure according to claim 6 is the structure according to claim 5, wherein a spring is provided in an attachment portion for attaching the cleaning member to the image forming apparatus, and the cleaning apparatus is arranged in the vertical direction of the image forming apparatus. Can be moved to.

  Here, when the protrusion on the shield housing contacts the casing of the cleaning device, the spring supporting the upper part of the mounting portion of the image forming apparatus is compressed, and the cleaning device moves upward by the height of the protrusion. To do. When the protrusion provided on the shield casing passes through the casing of the cleaning device, the water-containing member of the cleaning device moves downward by the spring and contacts the grid electrode of the scorotron charger.

  In the present invention, cleaning is performed by bringing the water-containing member into contact with the surface of the grid electrode, whereby ion products and toner attached to the surface of the grid electrode can be efficiently cleaned. Also, if the scorotron charger needs to avoid contact between the scorotron charger and the water-containing member, a protrusion is provided on the scorotron charger, and when the water-containing member reaches that portion during cleaning, the protrusion and the cleaning device come into contact with each other to clean The device is spaced from the scorotron charger. Therefore, the water-containing member does not come into contact with the scorotron charger at the portion where the protrusion is provided, and moisture contained in the water-containing member can be prevented from entering the charger from this portion.

[First Embodiment]
FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 includes an image forming unit 101 disposed substantially at the center, and includes a casing 102 containing the image forming unit 101 and the like, a paper feed unit 103, an automatic document transport unit 104, and the like. In addition to the scorotron charger 1 constituting the charging charger, the image forming unit 101 includes a photosensitive drum 40 and a developing device (not shown). The scorotron charger 1 as a charging charger is disposed below the photosensitive drum 40 and is slidable in the longitudinal direction (the axial direction of the photosensitive drum 40).

  As shown in FIG. 2, the scorotron charger 1 includes a shield housing 2, a corona discharge wire 3, and a grid electrode 4. The shield housing 2 has a U-shaped cross-sectional shape having a pair of side plates 2a and a bottom plate 2b, and is made of stainless steel having an opening. The discharge wire 3 is stretched in the shield housing 2, and the wire stretch position restricting members 9 provided at both ends in the longitudinal direction of the shield housing 2 so that the position of the discharge wire 3 does not shift. The supporting position is fixed by. The grid electrode plate 4 is for controlling the corona discharge current generated from the discharge wire 3, is provided so as to cover the open end of the shield housing 2, and is disposed at a position facing the photoconductor 40. Yes.

  Further, as described above, in the scorotron charger 1, in order to stabilize charging, it is necessary to keep the distance between the grid electrode portion 4a and the surface of the photosensitive member constant. Therefore, as shown in FIG. 2, a gap roller 6 is provided to control the distance between the grid electrode portion 4a and the photoreceptor 40. The gap roller 6 has shafts 7 on both sides thereof rotatably supported by bearings 8. The gap roller 6 is exposed from the opening 4 b of the grid electrode plate 4 and contacts the surface of the photoreceptor 40. Thereby, the distance between the grid electrode 4 and the surface of the photoreceptor 40 can be kept constant.

  FIG. 3 shows a cross section of the shield casing 2 at a portion where the gap roller 6 is provided. In FIG. 3, the right side of the center line shows a cross section of the shield housing 2 in a portion where the gap roller 6 is provided, and the left side of the center line shows a cross section of the shield housing 2 in a portion where the gap roller 6 is not provided. Show. As is apparent from FIGS. 3 and 2, outer edge portions 2 c that extend outward are formed at the upper ends of the pair of side plates 2 a of the shield housing 2. And about the part in which the gap roller 6 was provided among this outer edge part 2c, the projection part 2d extended upwards from the front-end | tip of the outer edge part 2c is formed. The protrusion 2 d is set so that the tip does not contact the photosensitive drum 40 and is higher than the uppermost position of the gap roller 6. Further, the length of the protruding portion 2d is longer than the gap roller 6 and is set to a length substantially equal to the length of the opening 4b of the grid electrode plate 4.

  FIG. 4 shows the cleaning device 20 of the scorotron charger 1. The cleaning device 20 includes a box-shaped casing 22 having an upper opening, a water-containing member 21 that protrudes from the upper opening of the casing 22 and can come into contact with the grid electrode portion 4a, and an image forming unit provided on the rear side surface of the casing 22. And a mounting portion 24 to 101. The water content of the water-containing member 21 is 6% to 40%. The cleaning device 20 is attached to the image forming unit 101 via the attachment portion 24. Note that protrusions slightly lower than the protruding height of the water-containing member 21 may be provided on the upper end of the casing 22 at both end edges 22 a and 22 b in the direction orthogonal to the longitudinal direction of the water-containing member 21.

  FIG. 5 shows the relationship between the scorotron charger 1 and the cleaning device 20 attached to the image forming unit 101. The scorotron charger 1 is slidably held in the case of the image forming unit 101 and can be easily pulled out of the image forming apparatus 100 by an operator. The pressing member 102 includes a pressing spring 103 attached to the case of the image forming unit 101, and a pressing link 104 having a structure capable of bending and extending provided at a free end portion of the pressing spring 103. Here, the pressing member 102 is provided to press the scorotron charger 1 in the direction of the photosensitive drum 40, and the gap roller 6 is applied to the surface of the photosensitive drum 40 by the urging force of the pressing member 102. The distance between the scorotron charger 1 and the surface of the photosensitive drum 40 is maintained constant.

  In addition, the cleaning device 20 for the scorotron charger 1 is provided at the drawer port of the scorotron charger 1 on the side surface of the image forming unit 101. When the scorotron charger 1 is inserted, the surface of the grid electrode 4 comes into contact with the water-containing member 21 of the cleaning device 20.

  Next, the cleaning operation of the cleaning device 20 of the scorotron charger 1 will be described. When the image forming process is repeated and ion products and toner are accumulated on the surface of the grid electrode 4, the scorotron charger 1 is cleaned.

  In this case, the cleaning device 20 is first attached to the drawer port of the scorotron charger 1 on the front side surface of the image forming unit 101. Thereafter, as shown in FIG. 5A, the scorotron charger 1 is slid in the longitudinal direction and pulled out of the image forming apparatus 100. When the exposed portion of the gap roller 6 of the scorotron charger 1 is pulled out below the cleaning device 20, the casing 22 of the cleaning device 20 is formed on the protrusion 2 d provided on the shield housing 2 as shown in FIG. Touch. Therefore, the water-containing member 21 of the cleaning device 20 does not come into contact with the gap roller 6, and moisture contained in the water-containing member 21 does not adhere to the gap roller 6. At this time, when the projection 22 of the shield housing 2 and the casing 22 of the cleaning device 20 come into contact with each other, the pressing spring 102 that biases and supports the scorotron charger 1 is compressed, and the scorotron charger 1 continues to be used in the image forming apparatus. 100 can be pulled out. When the protrusion 2d provided on the shield housing 2 passes through the casing 22 of the cleaning device 20, the scorotron charger 1 is moved upward by the biasing force of the pressing spring 102 as shown in FIG. The water-containing member 21 of the device 20 comes into contact with the grid electrode 4 of the scorotron charger 1. At that time, the ion product and toner attached to the grid electrode 4 are wiped off by the water-containing member 21.

  Next, when the scorotron charger 1 is set inside the image forming apparatus 100, the water-containing member 21 of the cleaning device 20 comes into contact with the surface of the grid electrode 4 again to wipe off the remaining deposits. When the scorotron charger 1 is further inserted into the image forming apparatus 100 and the exposed portion of the gap roller 6 reaches below the cleaning device 20, the protruding portion 2 d provided on the shield housing 2 becomes the casing 22 of the cleaning device 20. To touch. Therefore, the water-containing member 21 of the cleaning device 20 does not come into contact with the gap roller 6, and moisture contained in the water-containing member 21 does not adhere to the gap roller 6. Depending on how dirty the surface of the grid electrode 4 is, the cleaning effect can be improved by repeating the above operation 2-3 times.

  In the present embodiment, cleaning is performed by bringing the water-containing member 21 into contact with the surface of the grid electrode 4, whereby ion products and toner attached to the surface of the grid electrode 4 can be efficiently cleaned. At the same time, when the water-containing member 21 reaches above the gap roller 6, the casing 22 of the cleaning device 20 comes into contact with the protrusion 2 d provided on the shield housing 2 of the scorotron charger 1. There is no contact with the gap roller 6. Therefore, moisture does not adhere to the gap roller 6, and the occurrence of leakage during corona discharge can be suppressed.

[Second Embodiment]
FIG. 6 shows another embodiment in which the cleaning device 20 is attached so as to have an engagement structure that can freely move in the vertical direction of the side surface of the image forming unit 101. Here, the attachment portion 24 to the image forming unit 101 provided in the casing 22 of the cleaning device 20 is engaged with the attachment portion 24 a provided on the outer surface of the image forming unit 101. The upper portion of the mounting portion 24 a provided in the image forming unit 101 is supported via a spring 105, and has a structure that is movable in the vertical direction on the side surface of the image forming unit 101.

  In this embodiment, when the exposed portion of the gap roller 6 of the scorotron charger 1 is pulled out to the lower side of the cleaning device 20, as shown in FIG. 22 is contacted. Therefore, the water-containing member 21 of the cleaning device 20 does not come into contact with the gap roller 6, and moisture contained in the water-containing member 21 does not adhere to the gap roller 6. Further, when the protrusion 2d on the shield housing 2 and the casing 22 of the cleaning device 20 come into contact with each other, the spring 105 supporting the upper portion of the attachment portion 24a of the image forming unit 101 is compressed, and the cleaning device 20 detects the protrusion 2d. Move upward by the amount of. When the protrusion 2d provided on the shield housing 2 passes through the casing 22 of the cleaning device 20, the water-containing member 21 of the cleaning device 20 is moved downward by the spring 105 as shown in FIG. Contact the grid electrode 4 of the vessel 1.

  Further, when the scorotron charger 1 is set inside the image forming apparatus 100, it is almost the same as described above, and the water-containing member 21 is separated from the gap roller 6 at the protruding portion 2d on the shield housing 2, and other than that. In this part, the water-containing member 21 contacts the grid electrode 4 for cleaning.

1 is a schematic diagram of an image forming apparatus. The block diagram of a scorotron charger. The block diagram of the gap roller mounting position of the scorotron charger. The block diagram of a cleaning apparatus. Drawing showing the cleaning state of the 1st embodiment. Drawing showing the cleaning state of the 2nd embodiment.

1 Scorotron charger 2 Shield case 2 d Shield case protrusion 3 Corona discharge wire 4 a Grid electrode 6 Gap roller 20 Cleaning device 21 Water-containing member 22 Casing 40 Photoconductor

Claims (6)

A cleaning structure for cleaning a grid electrode of a scorotron charger that is disposed to face an image carrier in an image forming apparatus and is slidable with respect to an outlet of the image forming apparatus ,
The scorotron charger is provided at both ends of the shield housing, and is provided with a gap roller that defines a gap between the image carrier and the grid electrode,
The cleaning structure
A cleaning device having a casing attached to the outlet of the image forming apparatus, and a water-containing member that is partly exposed from the opening of the casing and that contacts and cleans the grid electrode;
A projection provided at a position facing the gap roller on the shield casing side plate , wherein the scorotron charger is slid and the water-containing member is slid on the grid electrode to clean the grid electrode. When performing, a scorotron charger cleaning structure provided with a protrusion that contacts the casing and separates the water-containing member and the grid electrode at the gap roller position .   The scorotron charger cleaning structure according to claim 1, wherein the cleaning device is disposed above the scorotron charger. The scorotron charger has openings on both ends in the longitudinal direction of the grid electrode,
The protrusion is provided so that the water-containing member is separated from the scorotron charger at the opening of the scorotron charger.
The scorotron charger cleaning structure according to claim 1.   The scorotron charger cleaning structure according to any one of claims 1 to 3, wherein the cleaning device has a protrusion on an end face of the casing on the opening side that can come into contact with the protrusion of the scorotron charger. A pressing member for pressing the scorotron charger toward the image carrier,
  The pressing member includes a pressing spring provided in a case of the image forming apparatus, and a pressing link provided between the pressing spring and the scorotron charger.
The scorotron charger cleaning structure according to claim 1.   A spring is provided in an attachment portion for attaching the cleaning member to the image forming apparatus, and the cleaning apparatus can be moved in the vertical direction of the image forming apparatus.
The scorotron charger cleaning structure according to claim 5.

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