JP4314202B2 - Electrostatic adsorption device and image forming apparatus - Google Patents

Description

  The present invention relates to an electrostatic adsorption device that adsorbs and conveys a recording medium such as paper, and an image forming apparatus such as an ink jet recording apparatus using the electrostatic adsorption device.

  For an electrostatic adsorption device that applies an electric field to the surface of the endless conveyance belt while charging it and attracts and conveys a recording medium such as paper, the paper is wound as it is without peeling off the belt. was there.

JP 2004-175490 A JP 10-166563 A

  For this reason, as described in Patent Documents 1 and 2, many devices have been proposed in which a separation claw is provided in the separation portion of the conveyor belt. The separation claw is configured to peel off the paper whose entire surface is adsorbed to the wide belt surface, and an appropriate number of claw portions are in sliding contact with the belt surface in the width direction. And the separation claw provided in this way increases the contact pressure with respect to the belt, so that the separation claw surely comes into sliding contact with the belt, and it becomes difficult for separation failure to occur.

  However, the separation claw has a problem that if the contact pressure on the belt is large, the life of the belt becomes extremely short. Therefore, it is preferable that the contact pressure of the separation claw on the belt is small. However, when the separation claw having a small contact pressure has variations in the contact position and contact angle with the belt, a part of the claw portion may be lifted from the belt surface. Then, there is a possibility that a paper jam may occur due to poor separation due to partly lifting of the separation claws.

  In view of such problems, the present invention is intended to provide an electrostatic attraction apparatus and an image forming apparatus that can reliably obtain a stable and good separation performance by preventing the separation claw from being lifted.

In order to solve the above-described problems, the present invention has an endless belt member wound around a plurality of rollers, and an electric field is applied to the surface of the belt member by charging means while rotating the belt member. In the electrostatic attraction apparatus for attracting and transporting a recording medium , the recording medium is disposed at a position facing a roller on the downstream side in the recording medium transport direction among the plurality of rollers, and is in sliding contact with the belt member so that the recording medium is moved to the belt. A separation claw to be peeled off from the member; a guide member that supports a roller provided on the downstream side in the recording medium conveyance direction and has a positioning receiving portion that positions the roller provided on the downstream side in the recording medium conveyance direction; the holding a plurality arranged the separating pawl in the width direction of the belt member, the separation pawl in the width direction of the belt member vanes positioned relative to said belt member Has the edge, and a separation claw holding unit provided detachably on said guide member, said vanes of said separation pawl holding unit, by being inserted into the positioning receiving portions of the guide member The electrostatic chucking device is characterized in that the separation claw is positioned with respect to the belt member.

The present invention is effective when the blade of the positioning member is engaged with and inserted into the positioning receiving portion by sliding and inserting the separation claw holding unit into the positioning receiving portion of the guide member. Is.
Further, according to the present invention, in the separation claw holding unit, the cleaning means for removing the paper dust adhered to the surface of the belt member and the surface of the belt member are contacted to remove the charge on the surface of the belt member. It is effective that at least one of the charge eliminating brushes is detachably attached to the separation claw holding unit .

Further, according to the present invention, the separation claw holding unit is provided with a plurality of the separation claws, and the separation claw is provided with a claw portion and a guide blade for guiding conveyance of the peeled recording medium. Is effective.

In order to solve the above problems, the present invention is characterized by using the electrostatic attraction apparatus according to any one of claims 1 to 4 .

  The present invention is effective when it has a recording head that forms an image by discharging droplets onto the recording medium.

According to the present invention, the contact position and contact angle of the separation claw can be accurately positioned, and the contact pressure on the belt can be reduced. Therefore, the recording medium can be reliably separated and the life of the belt can be prevented from being shortened.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing an overall configuration of an ink jet recording apparatus which is an embodiment of an image forming apparatus according to the present invention.

  The image forming apparatus includes an image forming unit 2 for forming an image inside an apparatus main body 1, and the image forming unit 2 transports a sheet as a recording medium in the sub-scanning direction and a sheet 5. Has a recording head 4 for forming an image. Although not shown, the recording head 4 of the present embodiment includes a plurality of line-type droplet discharge heads arranged side by side along the conveyance direction of the paper 5 and includes at least four droplets that discharge droplets of different colors. ing. The recording head 4 is mounted on a carriage (not shown), moves the carriage in the main scanning direction, and ejects liquid droplets from the recording head 4 while feeding the paper 5 in the paper transport direction (sub-scanning direction). It is a shuttle type that forms. The recording head 4 uses a piezoelectric element as a pressure generating means (actuator means) for pressurizing the ink in the ink flow path (pressure generation chamber) to deform the diaphragm that forms the wall surface of the ink flow path. A so-called piezo type that discharges ink droplets by changing the volume in the flow channel, or a so-called piezo type that discharges ink droplets with pressure by heating the ink in the ink flow channel and generating bubbles using a heating resistor. The thermal type, the diaphragm that forms the wall surface of the ink flow path and the electrode are placed opposite to each other, and the diaphragm is deformed by the electrostatic force generated between the vibration plate and the electrode, thereby reducing the volume of the ink flow path. It is possible to use an electrostatic type that discharges ink droplets by changing.

Next, the flow of paper during image formation will be described.
A main body paper feed unit 6 is provided below the image forming unit 2 of the apparatus main body 1, and when the paper feed roller 7 of the main body paper feed unit 6 is operated, the sheet 5 as a recording medium is prevented from being double fed (not shown). 1) are fed one by one. The fed paper 5 is abutted against the registration roller 8 in front of the image forming unit and aligned, and then conveyed to the conveying belt device 3, and an image is formed by the recording head 4 during the conveying belt device 3. . The paper 5 on which image formation has been completed is reversely discharged to a paper discharge unit 15 provided on the upper portion of the apparatus main body 1 via transport rollers 10, 11, 12, 13 and a paper discharge roller 14.

FIG. 2 is an enlarged explanatory view of a portion of the conveyance belt device 3 of the image forming apparatus shown in FIG.
The transport belt device 3 is an endless transport that spans between a transport roller 32 that is a driving roller and a driven roller 33 that is a tension roller for transporting a sheet 5 fed from below facing the recording head 4. A belt 3 is provided. In order to charge the surface of the conveying belt 31, a charging roller 34 that is a charging unit to which a high voltage, which is an alternating voltage, is applied from a high-voltage power source, and a guide member 35 that guides the conveying belt 31 in a region facing the recording head 4. And a pressing roller (pressure roller) 36 that presses the paper 5 against the transporting roller 31 at a position facing the transporting roller 32, and a separation claw for separating the paper 5 on which the image is formed by the recording head 4 from the transporting belt 31. 37.

  The conveyor belt device 3 is configured such that the conveyor belt 31 rotates in the direction of arrow A in FIG. 2 by rotating the conveyor roller 32 from the belt motor 131 via the timing belt 132 and the timing roller 133. . The transport belt 31 includes, for example, a surface layer that is a sheet adsorbing surface formed of a pure resin material that is not subjected to resistance control, such as ETFE pure material, and a back layer that is subjected to resistance control by carbon with the same surface layer as the village layer. A two-layer structure with (medium resistance layer, earth layer) can be employed.

  Further, as a cleaning means for removing paper dust and the like adhering to the surface of the conveyor belt 31 between the service roller 33 and the charging roller 34, for example, a cleaning film 45 made of Mylar (trade name) and a conveyor A neutralizing brush 46 for removing charges on the surface of the belt 31 is provided.

  As shown in FIG. 3, a plurality of separation claws 37, seven in this example, are provided, and a rotation shaft 37 a is pivotally supported on the support arm 41 of the separation claw holding unit 40. As shown in FIG. 4, the separation claw 37 is energized by a spring 42 inserted between the separation claw holding units 40, and the clockwise rotating force in FIG. The sliding contact pressure is applied. Each separation claw 37 is provided with guide blades 39 for guiding the paper 5 on both sides of the claw portion 38, and the guide blade 39 serves to reliably guide the separated paper 5 toward the transport roller. In addition to the separation claw 37, the separation claw holding unit 40 is detachably provided with the cleaning film 45 and the static elimination brush 46 described above.

  By the way, the separation pawl 37 is preferable in order to extend the life of the conveyor belt 31 as the pressure applied to the conveyor belt 31 is smaller. However, if the pressure of the separation claw 37 on the conveyance belt 31 is reduced, the contact position and angle of the claw varies, and the separation claw 37 is lifted from the conveyance belt 31 to cause a problem of separation failure. explained.

  Therefore, in the present invention, the separation claw 37 is positioned and installed on the conveyor belt 31 substantially directly. In the embodiment shown in FIG. 3 and FIG. 4, the separation claw holding unit 40 that supports the separation claw 37 is provided with positioning blades 43 on both sides, and this positioning blade 43 supports the driven roller 33 as shown in FIG. It is slid and mounted on a receiving portion 33b formed on the guide plate 33a.

Thus, by positioning and mounting on the guide plate 33a that supports the driven roller 33 , the contact position and contact angle of the separation claw 37 with respect to the transport belt 31 can be accurately determined.

  Further, as shown in FIG. 6, the separation claw 37 can obtain the same effect as the above-described embodiment even if the positioning blade 43 is attached to the receiving portion 51 provided on the adjustment sheet metal 50 for adjusting the position of the belt. It is done. The adjustment sheet metal 50 will be briefly described. As shown in FIG. 7, the conveyor belt device 3 is configured to be supported at four points, and the adjustment sheet metal 50 is provided at one of the points to adjust the position. I am doing so. As a result, the conveyor belt device 3 can be supported and attached by the sub-side plates 51 and 52 which are frame members while maintaining the flatness of the conveyor belt 31, and the conveyor belt 31 is removed or replaced. Even in this case, reproducibility of flatness can be maintained.

  That is, when the conveyor belt device 3 is configured to be supported at four points, if any of the four points is directly fixed to the sub-side plates 51 and 52 and the support plate 53, the conveyor belt device 3 itself may be shaken, distorted, or the like. It is difficult to obtain flatness, and if the sub-side plates 51 and 52 and the support plate 53 that are the frame members are distorted, they are directly affected. Even if it is used to forcibly attach the flatness, once it is removed, it becomes difficult to reproduce the flatness.

  On the other hand, when the three points are directly attached to the sub-side plates 51 and 52 and the support plate 53 which are frame members, they can be attached in a state in which there is generally no vibration or distortion. Therefore, the remaining point is to adjust the attachment position of the adjustment sheet metal 50 that can adjust the position according to the position of the conveyor belt device 3 where the flatness is obtained after fixing the three points and obtaining the flatness. By attaching to the adjustment sheet metal 50, the conveyor belt device 3 is hardly shaken or distorted. Therefore, even if it is removed once, the flatness can be reproduced at the time of reassembly or replacement.

  If the separation claw holding unit 40 is attached to the adjustment sheet metal 50 configured as described above, the contact position and the contact angle of the separation claw 37 with respect to the transport belt 31 can be accurately determined. Further, when the separation claw holding unit 40 is accurately attached to the transport belt 31, the installation position of the cleaning film 45 and the static elimination brush 46 that are detachably attached to the unit can always be set to the correct positions.

1 is a schematic configuration diagram illustrating an overall configuration of an inkjet recording apparatus that is an embodiment of an image forming apparatus according to the present invention. FIG. 2 is an explanatory diagram in which a portion of a conveyance belt device of the image forming apparatus illustrated in FIG. 1 is enlarged. It is a perspective view which shows a separation nail holding unit. It is side surface explanatory drawing which shows a separation nail holding unit. It is side surface explanatory drawing of the state mounted to the roller guide which shows a separation nail holding unit. It is sectional explanatory drawing which shows the sheet metal for belt adjustment. It is explanatory drawing explaining the effect | action of the sheet metal for belt adjustment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Image formation part 3 Conveyor belt apparatus 5 Paper 6 Main body paper feeding part 31 Conveyor belt 33b Receiving part 37 Separation claw 40 Separation claw holding unit 42 Positioning blade 50 Adjustment sheet metal 50

Claims (6)

In an electrostatic attraction apparatus having an endless belt member wound around a plurality of rollers, and adsorbing and conveying a recording medium by applying an electric field to the surface of the belt member by a charging unit while rotating the belt member ,
A separation claw that is disposed at a position facing a roller on the downstream side in the recording medium conveyance direction among the plurality of rollers, and is in sliding contact with the belt member to peel the recording medium from the belt member;
A guide member formed with a positioning receiving portion for supporting a roller provided on the downstream side in the recording medium conveyance direction and positioning a roller provided on the downstream side in the recording medium conveyance direction;
A plurality of the separation claws arranged in the width direction of the belt member are held, blades for positioning the separation claws with respect to the belt member are provided at both ends in the width direction of the belt member, and the guide member has A separation claw holding unit detachably provided, and
The electrostatic chucking apparatus, wherein the blades of the separation claw holding unit are inserted into the positioning receiving portion of the guide member so that the separation claw is positioned with respect to the belt member. The electrostatic chuck according to claim 1, wherein the blade of the positioning member is engaged with and inserted into the positioning receiving portion by sliding the separation claw holding unit into the positioning receiving portion of the guide member. An electrostatic chucking device characterized by being worn. 3. The electrostatic chuck according to claim 1, wherein the separation claw holding unit contacts the surface of the belt member in contact with a cleaning unit for removing paper dust attached to the surface of the belt member. At least one of the static elimination brush for removing the electric charge on the belt member surface is detachably attached to the separation claw holding unit. 4. The electrostatic chucking device according to claim 1 , wherein the separation claw holding unit is provided with a plurality of the separation claws, and the separation claws of the recording medium peeled off from the claw portions. An electrostatic chucking device comprising a guide blade for guiding conveyance. An image forming apparatus using the electrostatic attraction apparatus according to claim 1 . 6. The image forming apparatus according to claim 5 , further comprising a recording head that forms an image by ejecting liquid droplets onto the recording medium.

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