JP4568149B2 - Liquid image forming apparatus - Google Patents

Description

  The present invention relates to a liquid image forming apparatus employed in a copying machine, a facsimile machine, a printer, and the like.

In general, in an electrophotographic image forming apparatus, the surface of a photosensitive drum is uniformly charged by a charger, and an electrostatic latent image is formed by irradiating the surface of the photosensitive drum with light according to image information. The toner is formed on the photosensitive drum by supplying a developer to the electrostatic latent image. In this case, as shown in Patent Document 1, the interval between the photosensitive drum and the charger is made constant by bringing the roller into contact with the photosensitive drum. This is because it is necessary to uniformly charge the photosensitive drum, and for this reason, it is important to manage the distance between the grid and the wire provided in the charger.
JP 2002-365881 A

  By the way, in the case where the developer is a liquid developer comprising a toner whose liquid developer is a solid component and an insulating carrier liquid which is a liquid component, the roller is in contact with the photoconductor drum, so that the roller is supplied to the photoconductor drum. There is a risk that the liquid developer adheres to the roller surface, and the liquid developer that has adhered and accumulated leaks to the charger through the shaft portion of the roller and the charger is contaminated.

  An object of the present invention is to provide a liquid image forming apparatus including a positioning member that regulates a distance between an image carrier such as a photosensitive drum and a charging unit such as a charger, by a liquid developer attached to the positioning member. An object of the present invention is to provide a liquid image forming apparatus that prevents contamination of members other than a positioning member constituting a charging unit.

  In order to solve the above problems, the invention according to claim 1 is directed to an image carrier, a charging unit for charging the image carrier, and the charging unit and the image carrier in contact with the image carrier. A liquid image forming apparatus provided with a positioning member that regulates the interval between the liquid developer and the liquid developer collecting portion that guides the liquid developer attached to the positioning member to the liquid developer collecting unit so as not to adhere to the charging unit. The gist of the featured liquid image forming apparatus is as follows.

According to a second aspect of the present invention, in the first aspect, the liquid developer recovery unit is a storage container that stores the liquid developer.
A third aspect of the invention is characterized in that, in the first or second aspect, the liquid developer recovery section is provided outside the charging means.

  According to a fourth aspect of the present invention, the positioning member according to any one of the first to third aspects is provided so as to be rotatable in a case of the charging means. Further, one end is abutted against the positioning member and the other end is led out to the outside through the case.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the guide member is a film.

  According to the first aspect of the present invention, since the liquid developer attached to the positioning member can be guided to the liquid developer collecting unit by the guide member so as not to contaminate the charging unit, the charging unit is configured with a simple configuration. Contamination of the members other than the positioning member with the liquid developer can be prevented. Further, even if foreign matter other than the liquid developer adheres to the guide member, it can be wiped by the guide member, so that the distance between the image carrier and the charging means can always be kept constant.

  According to the invention of claim 2, since the liquid developer recovery unit is a storage container for storing the liquid developer, the liquid developer thus induced can be stored in the storage container. Contamination of the liquid developer in the peripheral device of the image carrier can also be prevented.

According to the third aspect of the present invention, the liquid developer attached to the positioning member is led out to the outside by the guide member, so that the charging means can be prevented from being contaminated by the liquid developer.
According to the fourth aspect of the present invention, the positioning member disposed in the case of the charging unit leads the liquid developer adhering to the positioning member to the outside by the guide member penetrating the case. Contamination by the liquid developer can be prevented.

  According to the invention of claim 5, even if the guide member is formed of a film, the effect of any one of claims 1 to 4 is obtained.

Hereinafter, an embodiment embodying a liquid image forming apparatus of the present invention will be described with reference to FIGS.
First, an outline of the image forming apparatus 50 will be described. As shown in FIG. 1, an image forming apparatus 50 includes a photosensitive drum 51, a main charging device 52, an LPH (LED PRINT HEAD) 53, a cleaning device 60, a charge eliminating lamp 57, a liquid developing device (developing a liquid developing device). Only the roller 54 is shown), a transfer roller 85, and the like.

  The photosensitive drum 51 is an amorphous silicon drum and is charged by the main charging device 52 at a developing position so as to have a predetermined dark potential. The LPH 53 irradiates the surface of the charged photoconductive drum 51 with light corresponding to image information, whereby an electrostatic latent image is formed on the surface of the photoconductive drum 51. The photosensitive drum 51 corresponds to an image carrier. The main charging device 52 corresponds to charging means.

  The developing roller 54 of the liquid developing device applies a liquid developer composed of toner and a carrier liquid to the photosensitive drum 51, and the liquid developer A is applied to the electrostatic latent image of the portion of the photosensitive drum 51 irradiated with the light. By applying this, a toner image is formed on the photosensitive drum 51.

  The toner image obtained by developing the electrostatic latent image formed as described above is transferred to an endless intermediate transfer belt 86 located in the nip with the transfer roller 85. The intermediate transfer belt 86 is formed of a resin belt, and a resin film such as PVdF (polyvinylidene fluoride), nylon, PET (polyethylene terephthalate), or polycarbonate can be used as the material of the resin belt. The toner that has not been transferred on the photosensitive drum 51 is scraped off by the cleaning blade 62 of the cleaning device 60 in the next process. The photosensitive drum 51 is neutralized by a neutralizing lamp 57 so as to lower the residual potential on the surface and make it uniform, and thereafter, it is prepared for the next series of processes.

(Main charging device 52)
The main charging device 52 will be described.
The main charging device 52 includes a shield member 100, a pair of block members 101 (see FIGS. 1, 5, and 6), a charging wire 102 (see FIG. 5), and a pair of rollers 103 (see FIGS. 1 and 2). And a grid 105 (see FIGS. 2 and 5) disposed to cover the open end of the shield member 100.

  The shield member 100 is formed so that the cross section has a channel shape, and the photosensitive drum 51 side is opened as shown in FIGS. The shield member 100 is formed in an elongated and linear shape as a whole with a metal such as SUS. The pair of side walls 100a of the shield member 100 are arranged in parallel with each other with a space therebetween, and their base ends are connected to each other at the bottom wall 100b. Then, both end portions of the shield member 100 are opened in the longitudinal direction.

  The pair of block members 101 are made of synthetic resin, and are fitted and fixed to the openings at both ends of the shield member 100, respectively. Since the configuration of the pair of block members 101 is substantially the same, only one block member 101 will be described, and the other description will be omitted. The block member 101 corresponds to a case.

  As shown in FIG. 1 and FIG. 5, the block member 101 includes a pair of side walls 101a and a bottom wall 101b that connects the longitudinal base ends of the side walls 101a. A shaped portion 101c is formed. In addition, one end side of the block member 101 includes an end wall 101d integrally connected to the pair of side walls 101a and the bottom wall 101b (see FIG. 5). One end of the channel-like portion 101c in the longitudinal direction is closed by the end wall 101d.

  In the bottom wall 101b, a wire positioning wall 101e is erected on the end portion side on the opposite end wall 101d side. A V-shaped groove 107 for positioning the charging wire 102 is formed in the center of the upper surface of the wire positioning wall 101e in the width direction (in FIG. 5, the direction orthogonal to the drawing, hereinafter the same). The charging wire 102 is stretched in a state in which both ends thereof are pressed against the grooves 107 of the wire positioning walls 101e in both block members 101, and are fixed to the block member 101 via coil springs and locking means (not shown). ing.

  As shown in FIGS. 5 and 1, between the end wall 101 d and the wire positioning wall 101 e, the block member 101 has a pair of roller bearing portions 108 for holding the rollers 103 in the longitudinal direction of the block member 101. Are formed at intervals. Each roller bearing portion 108 includes a pair of elastic holding pieces 109. The elastic holding pieces 109 are arranged so as to face each other with an interval in the width direction of the block member 101. An arc-shaped receiving portion 110 is formed at each base portion of the elastic holding piece 109.

  In each roller bearing portion 108, a bearing surface having a substantially circular inner peripheral surface is formed by the facing surface (surface facing in the width direction) of each elastic holding piece 109 and the surface of each receiving portion 110. A part of the bearing surface in the circumferential direction is opened between the tips of the elastic holding pieces 109. The bearing surfaces are arranged coaxially with each other. The distance between the tips of the elastic holding pieces 109 facing each other in the width direction is slightly shorter than the diameter of the circular inner peripheral surface.

  The roller 103 includes a roller body 103a and a shaft portion 103b that extends from both side surfaces of the roller body 103a on a common axis. The roller 103 is made of an appropriate synthetic resin. The synthetic resin is preferably a liquid-resistant developer. The roller 103 is rotatably held by the roller bearing portion 108 by inserting the shaft portion 103b into the bearing surface through the gap between the elastic holding pieces 109 of the roller bearing portion 108 of the block member 101. .

  Further, the shaft portion 103b of each roller 103 held rotatably by both block members 101 is disposed so as to be coaxial. Further, a part of the surface of the roller 103 rotatably held by each block member 101 is set so as to protrude from the outer surface of the grid 105 by a certain amount via an opening 105a of the grid 105 described later. .

  The roller main body 103a of each roller 103 is in contact with the surface of both ends of the photosensitive drum 51 in the axial direction, is driven to rotate by the rotational driving of the photosensitive drum 51, and is connected to the main charging device 52 for the photosensitive drum 51. The distance is kept constant so as to be always parallel. The roller 103 corresponds to a positioning member.

  The grid 105 is formed in a flat plate shape so as to extend in a strip shape with a constant width. The opening 105 a is disposed so as to cover the open end of the shield shape of the shield member 100, and is fixed to the open end of the shield member 100. As shown in FIG. 3 and FIG. 4, at both ends of the shield member 100, an opening 105 a is formed through a portion corresponding to the roller 103, and a part of the roller 103 protrudes outward. The grid 105 is arranged in parallel with the charging wire 102 and, as described above, the main charging device 52 is arranged in parallel with the main charging device 52, so that the grid 105 is always constant with respect to the photosensitive drum 51. Have been to keep away.

  Further, as shown in FIGS. 1 and 6, the main charging device 52 is closer to the cleaning device 60 than the position on the vertical line L extending downward from the rotation center axis O of the photosensitive drum 51. Are shifted by a predetermined angle θ (90 °> θ> 0). The predetermined angle θ is an angle between the vertical line L and the straight line L1 passing through the axis of the roller 103.

  Further, a pressing spring 115 as an urging member is disposed on the back side of the main charging device 52 (on the opposite side facing the photosensitive drum 51. The lower end of the pressing spring 115 is the housing 90 of the liquid image forming apparatus. The roller 103 of the main charging device 52 is urged so as to always abut against the photosensitive drum 51. The main charging device 52 is a guide (not shown) provided in the housing 90. Guided by the means, the roller 103 abuts against the photosensitive drum 51 by the urging force of the pressing spring 115.

  A mounting table 92 provided on the housing 90 is provided at a lower position outside the main charging device 52 corresponding to each roller 103 of the main charging device 52 (only one 92 is shown in FIG. 6). . On each mounting table 92, a liquid developer recovery unit and a disposal container 122 as a storage container are mounted. A support member 124 is erected on the bottom of each waste container 122. The upper portion of the waste container 122 is opened, and the upper end of the support member 124 is extended to be positioned above the waste container 122 through the opening. The upper end of the support member 124 is inserted into the channel-shaped portion 101c through the windows m1 and m2 formed on the side wall 100a and the side wall 101a of the main charging device 52, respectively.

  The width of the upper end of the support member 124 (the length in the left-right direction in FIG. 5) is shorter than the width of the windows m1 and m2 (the length in the left-right direction in FIG. 5). The windows m1 and m2 are not in contact with each other. The distance between the windows m1 and m2 and the support member 124 is set to a sufficient distance so that the liquid developer A dripping on the support member 124 does not touch.

  A guide piece 125 as a guide member is fixed to the upper end of the support member 124. The guide piece 125 is formed as a film made of synthetic resin or metal, and has elasticity. The leading end of the guide piece 125 is elastically counter-contacted with the roller body 103a of the roller 103 with respect to the rotation direction (that is, the driven rotation direction with respect to the photosensitive drum 51). Has been.

  The width of the guide piece 125 (the length in the left-right direction in FIG. 5) is larger than the length (that is, the thickness) in the axial direction of the roller body 103a. The width of the guide piece 125 is not necessarily larger than the length of the roller body 103a in the axial direction, and may be shortened. The point is that the length is sufficient to wipe the liquid developer A that is in contact with the circumferential surface of the roller body 103a and adheres to the circumferential surface of the roller body 103a. In the present embodiment, the portion of the leading end of the guiding piece 125 that contacts the photosensitive drum 51 is planar, but one or more slits from the leading end are formed in the length direction of the guiding piece 125. In other words, the branched portion may be elastically contacted. Further, the guide piece 125 is in counter contact with the rotation direction of the roller body 103a, but may be elastically contacted in the trail direction.

  In the liquid image forming apparatus configured as described above, the main charging device 52 is in contact with the photosensitive drum 51 via the roller 103 by the urging force of the pressing spring 115. That is, the photosensitive drum 51 and the main charging device 52 are held apart by a roller 103 at a constant distance.

  In this state, at the time of development, the photosensitive drum 51 is rotated in the direction of the arrow shown in FIG. 6, and the liquid developer is applied from the developing roller 54. A toner image is formed on the electrostatic latent image of the portion irradiated with light on the photosensitive drum 51. After the toner image is formed, the photosensitive drum 51 transfers the toner image to the intermediate transfer belt 86 by the action of the transfer roller 85, and then the remaining liquid developer A is removed by the cleaning blade 62 of the cleaning device 60. Removed.

  However, part of the liquid developer A may leak from the cleaning blade 62, and the leaked liquid developer A moves from the peripheral surface of the photosensitive drum 51 to the roller body 103 a of the roller 103. Since the guide piece 125 is elastically contacted with the liquid developer A moved to the roller body 103a, the guide piece 125 is wiped by the guide piece 125 and enters the waste container 122 through the guide piece 125 and the support member 124. . As a result, the liquid developer A does not move to the shaft portion 103b of the roller main body 103a, and contamination of the shaft portion 103b and the receiving portion 110 by the liquid developer A can be prevented.

  Further, not only the liquid developer A but also foreign matters below the liquid developer A can be wiped by the guide piece 125 even when the foreign material adheres to the roller body 103a. Therefore, the photosensitive drum 51, the main charging device 52, The interval can be kept constant at all times.

In addition, embodiment of this invention is not limited to said each embodiment, For example, you may implement | achieve as follows.
In the above-described embodiment, the roller 103 is disposed in the channel-shaped portion 101c of the block member 101. However, a roller 103 is rotatably held on the outer surface side of the side wall 101a, and the roller 103 is held by the member. You may make it do. In this case, the guide pieces 125 that contact the rollers 103 and the windows m1 and m2 for the support member 124 can be omitted, and processing for this is not necessary.

  In the above embodiment, the liquid developer recovery unit and the waste container 122 as a storage container are provided outside the main charging device 52. However, the waste container 122 is provided in the main charging device 52 to store the liquid developer. It may be.

  The liquid developer recovery unit is not limited to the storage container, and may be an adsorbent that adsorbs the liquid developer or an absorbent that absorbs the liquid developer.

1 is a schematic view of a liquid image forming apparatus according to an embodiment embodying the present invention. The perspective view of a main charging device. The perspective view which shows arrangement | positioning of a roller. The perspective view which similarly shows arrangement | positioning of a roller. Explanatory drawing showing the roller support structure Schematic which shows the arrangement | positioning state of the film of a guide member.

Explanation of symbols

50 ... Liquid image forming apparatus 52 ... Main charging device (charging means)
101 ... Block member (case)
103 ... Roller (positioning member)
122 ... Waste container (liquid developer recovery unit and storage container)
125 ... guide piece (guide member)
A ... Liquid developer

Claims (5)

In a liquid image forming apparatus comprising: an image carrier; a charging unit that charges the image carrier; and a positioning member that contacts the image carrier and regulates a distance between the charging unit and the image carrier.
A liquid image forming apparatus, comprising: a guide member that guides the liquid developer attached to the positioning member to the liquid developer recovery unit so as not to adhere to the charging unit.   The liquid image forming apparatus according to claim 1, wherein the liquid developer recovery unit is a storage container that stores the liquid developer.   The liquid image forming apparatus according to claim 1, wherein the liquid developer collecting unit is provided outside a charging unit.   The positioning member is disposed in the case of the charging means and is rotatably provided. The guide member is disposed through the case and has one end abutted on the positioning member. The liquid image forming apparatus according to claim 1, wherein an end passes through the case and is led out to the outside.   The liquid image forming apparatus according to claim 1, wherein the guide member is a film.

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