JP2009156932A - Developing device and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive developing device in which a developer carrier can make abut on or away from a latent image carrier without requiring the addition of a new member and a drastic configuration change and to provide an image forming apparatus using the developing device. <P>SOLUTION: The developing device includes: the developer carrier 20Y carrying liquid developer; a developer carrier cleaning blade 21Y removing the liquid developer on the developer carrier 20Y; and a rocking mechanism moving the developer carrier 20Y to a position where it comes into contact with or separates from the latent image carrier 10Y. A rocking support point 30aY is arranged so that when the developer carrier 20Y is rocked to the position where it separates from the latent image carrier 10Y by the rocking mechanism, an angle formed by the direction of the developer carrier cleaning blade 21Y and a gravitational line G is small. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device using a liquid developer in which toner is dispersed in a carrier liquid and an image forming apparatus using the developing device.

Conventionally, a developer carrying body that carries a liquid developer and a cleaning blade that cleans the liquid developer remaining on the surface of the developer carrying body are provided, and the liquid developer deposited on the cleaning blade is removed. As a means, there is a structure having an eccentric roller in the developing device.

  This eccentric roller can be independently driven to rotate, and is arranged so that the outer peripheral surface of the eccentric roller moves in the vicinity of the surface where the cleaned liquid developer flows, so that the accumulated liquid developer is sheared in the rotational direction. Give power. The gap between the outer peripheral surface of the eccentric roller and the cleaning blade surface is gradually narrowed, resulting in a shearing force that presses the deposited liquid developer against the cleaning blade surface. Further, as a means different from the eccentric roller, a rotating body having one or a plurality of wire members is arranged so that the wire member moves in the vicinity of the surface where the cleaned liquid developer flows, and the shearing force is applied similarly to the eccentric roller. It is also possible to prevent the deposition of the liquid developer.

JP 2001-296747 A

  However, in the technique described in Patent Document 1, a complex drive train or a single drive source is used to perform rotational drive and control of a rotating body having means for preventing the deposition by applying a shearing force to the remaining liquid developer. is required.

  Further, in order to prevent permanent distortion and the like, when a means for contacting / separating the developer carrying body with respect to the latent image carrying body is necessary, a mechanism for contacting / separating the entire developing device or a part of the developing device can be considered. In order to establish this mechanism, it is necessary to install a drive train or drive source of the rotating body in the developing device so as to be compatible with the mechanism. Therefore, there is a possibility that it is disadvantageous in terms of downsizing and cost.

  In order to solve the above-described problems, the present invention does not require the addition of a new member or a significant change in configuration, and enables a developer carrier to be brought into contact with and separated from the latent image carrier and is low in cost. It is an object of the present invention to provide a developing device and an image forming apparatus using the developing device.

  The developing device of the present invention includes a developer carrying member carrying a liquid developer, a developer carrying member cleaning blade for cleaning the liquid developer on the developer carrying member, and the developer carrying member as a latent image carrying member. And a swing mechanism that moves the developer carrier to a position that is separated from the latent image carrier by the swing mechanism. Since the rocking fulcrum is arranged so that the angle between the direction of the body cleaning blade and the gravity line is small, the liquid developer deposited on the surface of the developer carrying body cleaning blade is easily dropped by gravity, and the developer The liquid developer on the surface of the carrier cleaning blade can be reduced. In addition, it is not necessary to add new members or change the configuration significantly, and the device can be easily reduced in size and cost.

  In addition, since the developer carrying member is provided with a rocking fulcrum so as to be pressed against the latent image carrier in the clearance direction, the toner layer on the latent image carrier is more than the pressure rotating in the biting direction. Can be reduced.

  In addition, since the developer carrier is rotated in a state where the developer carrier is separated from the latent image carrier, the liquid on the developer carrier is not developed on the latent image carrier. The developer can be cleaned with a developer carrier cleaning blade and dropped by gravity.

A developer supplying member that supplies a liquid developer to the developer carrying member; and a developer regulating blade that regulates an amount of the liquid developer on the developer supplying member. Since the swing fulcrum is arranged so that the angle formed between the direction of the developer regulating blade and the horizontal line becomes small when the developer carrier swings to a position separated from the latent image carrier.
The liquid developer remaining in the vicinity of the developer regulating blade during non-image formation can be reduced, the clogging of the developer supply member can be reduced, and the supply amount can be quantified.

  A developer compressing device that compresses the toner of the liquid developer on the developer carrier, and the developer carrier is swung to a position spaced apart from the latent image carrier by the swing mechanism; Since the swing fulcrum is arranged so that the angle formed between the surface of the developer compressing device and the gravitational line becomes small, contamination of the developer compressing device with the liquid developer can be reduced.

  Further, the image forming apparatus of the present invention includes a latent image carrier that develops a latent image by the developer carrier, a charger that charges the latent image carrier, and an exposure device that exposes the latent image carrier. And a transfer member for transferring the image on the latent image carrier, it is possible to form an image with good image quality.

  A liquid container that stores the liquid developer; and a squeeze device that removes excess liquid developer from the liquid developer on the latent image carrier, and the liquid developer removed by the squeeze device. The developer is dropped on the developer carrier cleaning blade, and the liquid developer dropped on the developer carrier cleaning blade and the liquid developer cleaned by the developer carrier cleaning blade are dropped on the developer container. Therefore, the liquid developer on the surface of the developer carrying member cleaning blade is easy to flow, and it is not necessary to add a member for that purpose. Therefore, the apparatus can be reduced in size and cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing main components constituting the image forming apparatus according to the embodiment of the present invention. Development units 30Y, 30M, 30C, and 30K as developing devices, and developer collection and supply devices 70Y, 70M, 70C, and 70K are formed on the latent image carrier 10Y of each color disposed in the center of the image forming apparatus. The intermediate transfer belt 40 and the secondary transfer unit 60, which are arranged at the lower part of the apparatus and serve as intermediate transfer members, are arranged at the upper part of the image forming apparatus.

  Around the latent image carriers 10Y, 10M, 10C, and 10K, chargers 11Y, 11M, 11C, and 11K, exposure units 12Y, 12M, 12C, and 12K are provided. The exposure units 12Y, 12M, 12C, and 12K include line heads and the like in which LEDs are arranged, and the latent image carriers 10Y, 10M, 10C, and 10K are uniformly charged by the chargers 11Y, 11M, 11C, and 11K. The exposure units 12Y, 12M, 12C, and 12K irradiate a modulated laser beam based on the input image signal, and electrostatic latent images on the charged latent image carriers 10Y, 10M, 10C, and 10K. Form an image.

  The developing units 30Y, 30M, 30C, and 30K are roughly composed of developing rollers 20Y, 20M, 20C, and 20K as developer carriers, yellow (Y), magenta (M), cyan (C), and black (K). Developer containers 31Y, 31M, 31C, and 31K that store liquid developers of the respective colors, and development that supplies the liquid developers of these colors from the developer containers 31Y, 31M, 31C, and 31K to the developing rollers 20Y, 20M, 20C, and 20K Developer supply rollers 32Y, 32M, 32C, and 32K as agent supply members are provided, and the electrostatic latent images formed on the latent image carriers 10Y, 10M, 10C, and 10K are developed with liquid developers of respective colors.

  The intermediate transfer belt 40 is an endless belt member and is wound around and stretched between a driving roller 41 and a tension roller 42, and the latent image carriers 10Y, 10M, and 50K are primary transfer units 50Y, 50M, 50C, and 50K. It is rotationally driven by the drive roller 41 while abutting 10C and 10K. The primary transfer units 50Y, 50M, 50C, and 50K are arranged such that the primary transfer rollers 51Y, 51M, 51C, and 51K face each other with the intermediate transfer belt 40 sandwiched between the latent image carriers 10Y, 10M, 10C, and 10K. The developed toner image of each color on the latent image carriers 10Y, 10M, 10C, and 10K is sequentially superimposed and transferred onto the intermediate transfer belt 40 using the contact position with 10Y, 10M, 10C, and 10K as a transfer position. A full-color toner image is formed.

  In the secondary transfer unit 60, a secondary transfer roller 61 is disposed opposite to the belt driving roller 41 with the intermediate transfer belt 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 and a developer recovery unit 63 is disposed. The In the secondary transfer unit 60, the sheet material conveyance path L is adjusted in accordance with the timing at which a full-color toner image or a single-color toner image formed by superimposing colors on the intermediate transfer belt 40 reaches the transfer position of the secondary transfer unit 60. Then, a sheet material such as paper, film or cloth is conveyed and supplied, and a single-color toner image or a full-color toner image is secondarily transferred to the sheet material. A fixing unit (not shown) is disposed in front of the sheet material conveyance path L, and a single color toner image or a full color toner image transferred onto the sheet material is fused and fixed to a recording medium (sheet material) such as paper. Image formation on the final sheet material is completed.

  On the side of the tension roller 42 that stretches the intermediate transfer belt 40 together with the belt drive roller 41, a cleaning device including an intermediate transfer belt cleaning blade 46 and a developer recovery unit 47 is disposed along the outer periphery thereof. The intermediate transfer belt 40 that has passed through the unit 60 proceeds to the winding portion of the tension roller 42, the intermediate transfer belt cleaning blade 46 performs cleaning on the intermediate transfer belt 40, and again proceeds to the primary transfer unit 50. .

  Developer collecting and replenishing devices 70Y, 70M, 70C and 70K adjust the concentration of the liquid developer collected from the latent image carriers 10Y, 10M, 10C and 10K and the developing units 30Y, 30M, 30C and 30K, and Supply to 31Y, 31M, 31C, 31K.

  Next, the latent image carriers 10Y, 10M, 10C, and 10K and the developing units 30Y, 30M, 30C, and 30K will be described. FIG. 2 is a cross-sectional view showing the main components of the periphery of the latent image carrier 10Y and the developing unit 30Y. 3 is a diagram for explaining the developer supply member, FIG. 4 is a diagram for explaining the compression of the developer by the developer compressing device 22Y, FIG. 5 is a diagram for explaining the development by the developing roller 20Y, and FIG. 6 is by the squeeze roller 13Y. It is a figure explaining a squeeze effect | action. Since the configurations of the latent image carriers 10Y, 10M, 10C, and 10K for each color and the developing units 30Y, 30M, 30C, and 30K are the same, the following description is based on the periphery of the latent image carrier 10Y for yellow (Y) and the developing unit 30Y. I will explain.

  The periphery of the latent image carrier 10Y is arranged along the rotational direction of the outer periphery of the latent image carrier 10Y along with a discharging device 16Y, a cleaning device including a latent image carrier cleaning blade 17Y and a developer recovery unit 18Y, a charger 11Y, and an exposure unit. 12Y, a developing roller 20Y of the developing unit 30Y, a first squeeze device 13Y comprising a first squeeze roller 13aY and a first squeeze roller cleaning blade 13bY, and a second squeeze device comprising a second squeeze roller 14aY and a second squeeze roller cleaning blade 14bY. 14Y is arranged. In the developing unit 30Y, a developing roller cleaning blade 21Y as a developer carrier cleaning blade and a developer supply roller 32Y using an anilox roller are arranged on the outer periphery of the developing roller 20Y. The liquid developer stirring paddle 36Y and the developer supply roller 32Y as a stirring member are accommodated. A primary transfer roller 51Y of the primary transfer portion is disposed along the intermediate transfer belt 40 at a position facing the latent image carrier 10Y.

  The latent image carrier 10Y is a photosensitive drum made of a cylindrical member having a width wider than about 320 mm of the developing roller 20Y and having a photosensitive layer formed on the outer peripheral surface. For example, as shown in FIG. Rotate. The photosensitive layer of the latent image carrier 10Y includes an organic latent image carrier or an amorphous silicon latent image carrier. The charger 11Y is disposed upstream of the nip portion between the latent image carrier 10Y and the developing roller 20Y in the rotation direction of the latent image carrier 10Y, and has a bias having the same polarity as the charging polarity of the developing toner particles from a power supply device (not shown). Is applied to charge the latent image carrier 10Y. The exposure unit 12Y exposes the latent image carrier 10Y charged by the charger 11Y downstream of the charger 11Y in the rotation direction of the latent image carrier 10Y, and forms a latent image on the latent image carrier 10Y. To do.

  The developing unit 30Y includes a developing roller 20Y that carries the liquid developer, a developing roller cleaning blade 21Y that cleans the developing roller 20Y, a developer compression member 22Y that forms a compressed state on the developer on the developing roller 20Y, and liquid development. The toner is dispersed in an approximately 25% weight ratio in the carrier liquid by the developer supply roller 32Y and the developer regulating blade 33Y for stirring and maintaining the agent in a uniform dispersed state and supplying it to the developing roller 20Y. A developer container 31Y for storing the liquid developer in a state; The developer container 31Y includes a supply unit 31aY and a recovery unit 31bY. The supply unit 31aY is a stirring paddle 36Y that stirs the developer in the developer container 31Y, and a liquid developer storage unit 71Y described later in the stirring paddle 36Y. The collecting unit 31bY collects the liquid developer scraped off by the developing roller cleaning blade 21Y, the first squeeze roller cleaning blade 13bY, and the second squeeze roller cleaning blade 14bY. And a recovery screw 34Y to be sent to the liquid developer reservoir 71Y.

  The liquid developer accommodated in the developer container 31Y is a low concentration (about 1 to 2 wt%) and low viscosity, which is conventionally used, using Isopar (trademark: Exxon) as a carrier liquid. It is not a volatile liquid developer having volatility, but a non-volatile liquid developer having a high concentration and high viscosity and having non-volatility at room temperature. That is, in the liquid developer in the present invention, a solid having an average particle diameter of 1 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin is introduced into a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil. It is a liquid developer having a high viscosity (about 30 to 10,000 mPa · s) which is added together with a dispersant and has a toner solid content concentration of about 25%.

  As shown in FIG. 3, the developer supply roller 32 </ b> Y is a cylindrical member, and an anilox having an uneven surface formed by fine and uniform spiral grooves on the surface so as to easily carry the developer on the surface. For example, as shown in FIG. 2, the roller rotates in the clockwise direction. The groove dimensions are such that the groove pitch is about 130 μm and the groove depth is about 30 μm. The developer supply roller 32Y supplies the liquid developer from the developer container 31Y to the developing roller 20Y. The agitation paddle 36Y and the developer supply roller 32Y may be in sliding contact with each other, but may be in a disposition relationship.

  The developer regulating blade 33Y is composed of an elastic blade having a surface covered with an elastic body, a rubber portion made of urethane rubber or the like that comes into contact with the surface of the developer supply roller 32Y, and a metal plate or the like that supports the rubber portion. Composed. Then, the film thickness and amount of the liquid developer carried and conveyed by the developer supply roller 32Y composed of an anilox roller are regulated and adjusted, and the amount of liquid developer supplied to the developing roller 20Y is adjusted. Note that the rotation direction of the developer supply roller 32Y may be the opposite direction instead of the arrow direction shown in FIG. 2, and the developer regulating blade 33Y at that time requires an arrangement corresponding to the rotation direction.

  The developing roller 20Y is a cylindrical member having a width of about 320 mm, and rotates counterclockwise around the rotation axis as shown in FIG. The developing roller 20Y is provided with an elastic layer made of polyurethane rubber, silicon rubber, NBR or the like on the outer periphery of an inner core made of metal such as iron. The developing roller cleaning blade 21Y is made of rubber or the like that comes into contact with the surface of the developing roller 20Y, and is arranged downstream of the developing nip portion where the developing roller 20Y comes into contact with the latent image carrier 10Y in the rotation direction of the developing roller 20Y. The liquid developer remaining on the developing roller 20Y is scraped off and removed.

  The developer compressing device 22Y applies corona discharge from a corona discharger. As shown in FIG. 4, the developer compressing device 22Y moves the toner T uniformly dispersed in the carrier liquid C to the developing roller 20Y side and aggregates it to form a so-called developer compressed state T ′.

  As shown in FIG. 5, the developer D carried by the developing roller 20Y and compressed by the developer is applied to the latent image carrier by applying a desired electric field at the developing nip where the developing roller 20Y contacts the latent image carrier 10Y. Development is performed corresponding to the latent image of 10Y. The undeveloped developer D is scraped off and removed by the developing roller cleaning blade 21Y and is collected on the developer collecting screw 34Y side in the developer container 31Y. Note that the carrier liquid and toner to be merged are not in a mixed color state.

  Next, a squeeze device as a carrier liquid removing device will be described. The squeeze device of the present embodiment has a first squeeze device 13 and a second squeeze device 14, and is arranged on the downstream side of the developing roller 20Y so as to face the latent image carrier 10Y, and is attached to the latent image carrier 10Y. It always abuts and collects the excess developer of the developed toner image.

  As shown in FIG. 6, the first squeeze device 13 includes a first squeeze roller 13aY composed of an elastic roller member that covers a surface of the first elastic body 13a-1Y and rotates in sliding contact with the latent image carrier 10Y. As shown in FIG. 2, it comprises a first squeeze roller cleaning blade 13bY that presses and slides against the first squeeze roller 13aY to clean the surface.

  Similarly to the first squeeze device 13 shown in FIG. 6, the second squeeze device 14 is an elastic roller member that covers the surface of the second elastic body 14a-1Y and rotates in sliding contact with the latent image carrier 10Y. 2 and a second squeeze roller cleaning blade 14bY that presses and slides against the second squeeze roller 14aY to clean the surface, as shown in FIG.

  The squeeze devices 13 and 14 have a function of collecting excess carrier liquid C and originally unnecessary fog toner T ″ from the developer D developed on the latent image carrier 10Y and increasing the toner particle ratio in the visible image. The recovery ability of the surplus carrier liquid C is relative to the rotation direction of the first squeeze roller 13aY and the second squeeze roller 14aY and the surface of the first squeeze roller 13aY and the second squeeze roller 14aY with respect to the peripheral speed of the surface of the latent image carrier 10Y. It is possible to set the desired recovery capability according to the peripheral speed difference, and the recovery capability increases if the latent image carrier 10Y is rotated in the counter direction. In addition, this synergistic effect is possible.

  The excess carrier liquid C and unnecessary fog toner T ″ collected by the first squeeze roller 13aY and the second squeeze roller 14aY are removed by the action of the first squeeze roller cleaning blade 13bY and the second squeeze roller cleaning blade 14bY. 13aY and the second squeeze roller 14aY are collected on the developer collection screw 34Y side of the developer container 31Y. The collected excess carrier liquid C and fog toner T ″ are collected from a dedicated isolated latent image carrier 10Y. Since it is collected, color mixing phenomenon does not occur in all locations.

  In the primary transfer unit 50Y, the developer image developed on the latent image carrier 10Y is transferred to the intermediate transfer belt 40 by the primary transfer roller 51Y. Here, the latent image carrier 10Y and the intermediate transfer belt 40 are configured to move at the same speed, so that the driving load of rotation and movement is reduced, and the disturbance effect on the visible toner image of the latent image carrier 10Y is suppressed. is doing.

  The developer recovery and supply device 70Y stores the recovered liquid developer, supplies a high concentration developer from the developer tank 74Y, and supplies a carrier liquid from the carrier liquid tank 77Y, and adjusts the concentration thereof. Have

  In the present embodiment, the liquid developer is recovered from the developing unit 30Y and the latent image carrier 10Y. The liquid developer recovered on the developer recovery screw 34Y side of the development unit 30Y is recovered in the liquid developer storage portion 71Y via the development unit recovery path 72Y. Further, the liquid developer recovered from the latent image carrier 10Y by the latent image carrier cleaning device 15Y including the latent image carrier cleaning blade 17Y and the developer recovery unit 18Y passes through the latent image carrier recovery path 73Y. The developer is collected in the developer reservoir 71Y.

  Further, the high-concentration developer is supplied from the developer tank 74Y to the liquid developer storage portion 71Y via the developer supply path 75Y and the developer pump 76Y. Further, the carrier liquid is supplied from the carrier liquid tank 77Y to the liquid developer storage section 71Y via the carrier liquid supply path 78Y and the carrier liquid pump 79Y. In addition, it is good also as a structure which replenishes by opening and closing of a valve etc. using gravity instead of a pump etc.

  The liquid developer stored in the liquid developer storage portion 71Y is supplied to the developer container 31Y through the supply portion 35Y via the developer supply path 81Y and the developer supply pump 82Y.

  Next, the operation of the image forming apparatus of the present invention will be described. Subsequently, with respect to the latent image carriers 10Y, 10M, 10C, and 10K and the developing units 30Y, 30M, 30C, and 30K, the four latent image carriers 10Y, 10M, 10C, and 10K and the developing units 30Y, 30M, and 30C, A description will be given by taking the periphery of the latent image carrier 10Y of yellow and the developing unit 30Y as an example.

In the developer container 31Y, the toner particles in the liquid developer have a positive charge, and this liquid developer is stirred by the stirring paddle 36Y, and the developer supply roller 32Y rotates, whereby the developer container 31Y. Pumped from.
The developer regulating blade 33Y is in contact with the surface of the developer supply roller 32Y, leaving the liquid developer in the uneven grooves of the anilox pattern formed on the surface of the developer supply roller 32Y, and other excess liquid developer. The amount of liquid developer supplied to the developing roller 20Y is regulated. By such regulation, the film thickness of the liquid developer applied to the developing roller 20Y is quantified so as to be about 6 μm. The liquid developer scraped by the developer regulating blade 33Y is dropped back into the developer container 31Y by gravity, and the liquid developer that has not been scraped by the regulating blade 33Y is uneven on the surface of the developer supply roller 32Y. Is applied to the surface of the developing roller 20Y by being pressed against the developing roller 20Y.

  The developing roller 20Y coated with the liquid developer by the developer supply roller 32Y contacts the developer compression device 22Y downstream of the nip portion with the developer supply roller 32Y. A bias of about +400 V is applied to the developing roller 20Y, and a bias that is higher than the developing roller 20Y and has the same polarity as the toner charging polarity is applied to the developer compression device 22Y. For example, a bias of about +4 kV is applied to the developer compression device 22Y.

  The latent image carrier 10Y is made of amorphous silicon, and after the surface is charged to about +600 V by the charger 11Y upstream of the nip portion with the developing roller 20Y, the potential of the image portion is +25 V by the exposure unit 12Y. A latent image is formed. In the developing nip portion formed between the developing roller 20Y and the latent image carrier 10Y, the bias + 400V applied to the developing roller 20Y and the latent image on the latent image carrier 10Y (image portion + 25V, non-image portion + 600V). 5), the toner particles T are selectively moved to the image portion on the latent image carrier 10Y as shown in FIG. 5, thereby forming a toner image on the latent image carrier 10Y. The Further, since the carrier liquid C is not affected by the electric field, as shown in FIG. 5, it is separated at the developing nip exit between the developing roller 20Y and the latent image carrier 10Y, and the developing roller 20Y and the latent image carrier 10Y are separated. Adhere to both.

  The latent image carrier 10Y that has passed through the developing nip portion passes through the squeeze roller 13Y portion. As shown in FIG. 6, the squeeze roller 13Y collects excess carrier liquid C and originally unnecessary fog toner T ″ from the developer D developed on the latent image carrier 10Y, and increases the toner particle ratio in the visible image. The surplus carrier liquid C can be collected in the surface of the first squeeze roller 13aY and the second squeeze roller 14aY with respect to the rotation direction of the first squeeze roller 13aY and the second squeeze roller 14aY and the peripheral speed of the surface of the latent image carrier 10Y. It is possible to set the desired recovery capability according to the relative peripheral speed difference between them, and the recovery capability increases when the latent image carrier 10Y is rotated in the counter direction, and the peripheral speed difference is set large. In addition, the recovery capability is increased, and this synergistic effect is also possible.

  In the present embodiment, as shown in FIG. 6, as an example, the first squeeze roller 13aY and the second squeeze roller 14aY are rotated with respect to the latent image carrier 10Y at substantially the same peripheral speed, and developed to the latent image carrier 10Y. The excess carrier liquid C having a weight ratio of about 5 to 10% is recovered from the developer D to reduce both rotational driving loads and suppress the disturbance effect on the visible toner image of the latent image carrier 10Y. Yes.

  Next, the latent image carrier 10Y passes through the nip portion with the intermediate transfer belt 40 in the primary transfer 50Y, and primary transfer of the visible toner image to the intermediate transfer belt 40 is performed. The primary transfer roller 51Y is applied with about -200 V having the opposite polarity to the charging characteristics of the toner particles, so that the toner is primarily transferred from the latent image carrier 10Y to the intermediate transfer belt 40, and is transferred to the latent image carrier 10Y. Only the carrier liquid remains. On the downstream side in the rotation direction of the latent image carrier 10Y from the primary transfer portion, the latent image carrier 10Y after the primary transfer is erased by the static eliminator 16Y composed of an LED or the like, and the latent image carrier 10Y is placed on the latent image carrier 10Y. The remaining carrier liquid is scraped off by the latent image carrier cleaning blade 17Y and recovered by the developer recovery unit 18Y.

  The toner images on the intermediate transfer belt 40 on which the toner images formed on the plurality of latent image carriers 10 are successively primary-transferred and carried are then transferred to the secondary transfer unit 60 where the intermediate transfer belt 40 and the secondary transfer belt 40 are secondary-transferred. It enters the nip portion with the transfer roller 61. The nip width at this time is set to 3 mm. In the secondary transfer unit 60, −1200 V is applied to the secondary transfer roller 61 and +200 V is applied to the belt driving roller 41, whereby the toner image on the intermediate transfer belt 40 is a recording medium such as paper. Transferred to (sheet material).

  However, when a sheet material supply trouble such as a jam occurs, not all toner images are transferred to the secondary transfer roll and collected, and a part of the toner image remains on the intermediate transfer belt. Even during the transfer process, the toner image on the intermediate transfer belt is not 100% secondary transferred and transferred to the sheet material, and a secondary transfer residue of several percent occurs. In particular, when a sheet material supply trouble such as a jam occurs, the toner image is transferred in contact with the secondary transfer roller 61 without the sheet material interposed, and the back surface of the sheet material is stained.

  In the present embodiment, the carrier liquid is recovered (squeezed) on the secondary transfer roller 61 side with respect to these unnecessary toner images, and the intermediate transfer belt cleaning blade 46 and the developer recovery unit 47 clean the intermediate transfer belt 40. The secondary transfer roller 61 is cleaned by the secondary transfer roller cleaning blade 62.

  Next, the swing mechanism of the developing unit 30Y of this embodiment will be described. 7 and 8 are views showing a state in which the developing unit 30Y is in contact with the latent image carrier 10Y, and FIG. 9 is a view showing a state in which the developing unit 30Y is separated from the latent image carrier 10Y.

  The developing unit 30Y of the present embodiment is centered on the swinging fulcrum 30aY at a position where it abuts and separates from the latent image carrier 10Y during non-image formation, etc., as a countermeasure against permanent distortion of the developing roller 20Y. It is movable. The swing fulcrum 30aY is a shaft-like member such as a pin provided at the lower part of the developer container 31Y on the image carrier 10Y side, and the rotational driving force is performed by a motor or the like (not shown).

  For example, in the present embodiment, as shown in FIG. 7, when the developing unit 30Y is in contact with the latent image carrier 10Y, a line A1 connecting the swing fulcrum 30aY and the center of the developing roller 20Y is a gravity line G. On the other hand, it is set to about 11.8 degrees. At this time, the direction A2 of the developing roller cleaning blade 21Y is set to about 30 degrees with respect to the gravity line G, and the direction A3 of the developer regulating blade 33Y is set to about 45 degrees with respect to the horizontal line H. The surface A4 of the compression device 22Y is set to about 37.95 degrees with respect to the gravity line G.

  Further, as shown in FIG. 8, the angle a formed by the line A1 connecting the swing fulcrum 30aY and the center of the developing roller 20Y and the line A5 connecting the centers of the developing roller 20Y and the latent image carrier 10Y is 0 degrees <a <180 degrees, and the developing roller 20Y is set so as to be pressed against the latent image carrier 10Y in the escape direction. By making the pressure rotation in the escape direction, the influence of the developing roller 20Y on the toner layer on the latent image carrier 10Y can be reduced compared to the pressure rotation in the biting direction.

  As shown in FIG. 9, the developing unit 30Y having such a configuration is rotated about 5 degrees around the swing fulcrum 30aY during non-image formation, and is separated from the latent image carrier 10Y, so that the swing fulcrum 30aY and the developing roller A line A1 connecting the centers of 20Y is arranged at a position of about 16.8 degrees with respect to the gravity line G. As a result, the direction A2 of the developing roller cleaning blade 21Y is smaller than the angle formed with the gravity line G and is arranged at about 25 degrees with respect to the gravity line G. When the angle formed with the gravity line G is small, the liquid developer deposited on the surface of the developer carrying member cleaning blade 21Y is likely to be dropped by gravity, and the liquid developer on the surface of the developer carrying member cleaning blade 21Y is reduced. can do.

  Further, the direction A3 of the developer regulating blade 33Y approaches the horizontal line H and is disposed at 40 degrees with respect to the horizontal line H. Then, the liquid developer remaining in the vicinity of the developer regulating blade 33Y during non-image formation is reduced, and clogging of the developer supply member 32Y is reduced.

  Further, the surface A4 of the developer compressing device 22Y has a small angle with the gravity line G, and is 32.95 degrees with respect to the gravity line G. Even if the liquid developer adheres to the surface of the developer compressing device 22Y, it tends to drop due to gravity.

  The rotating body in the developing unit 30Y, for example, the developing roller 20Y, the developer supply roller 32Y, the stirring paddle 36Y, and the like have their own drive source (not shown), and the developing unit 30Y is separated from the latent image carrier 10Y. Each state is rotatable. For example, when the developing roller 20Y is rotated in a state where the developing unit 30Y is separated from the latent image carrier 10Y, the liquid developer on the developer roller 20Y is not developed on the latent image carrier 10Y without developing the liquid developer. The toner can be cleaned by the developer carrying member cleaning blade 21Y and dropped by gravity.

  Further, as shown in FIG. 10, a developer container 31Y for storing the liquid developer and squeeze devices 13Y and 14Y for removing excess liquid developer from the liquid developer on the latent image carrier 10Y are provided. Then, the liquid developer D1 removed by the squeeze devices 13Y and 14Y is dropped onto the developer carrier cleaning blade 21Y. The liquid developer dropped on the developer carrying member cleaning blade 21Y and the liquid developer D2 cleaned by the developer carrying member cleaning blade 21Y are both dropped on the developer container 31Y.

  As described above, the developing device 30Y according to the present embodiment includes the developer carrier 20Y that carries the liquid developer, the developer carrier cleaning blade 21Y that cleans the liquid developer on the developer carrier 20Y, and the developer. And a rocking mechanism for moving the carrier 20Y to a position where the carrier 20Y contacts and separates from the latent image carrier 10Y, and the developer carrier 20Y is rocked to a position separated from the latent image carrier 10Y by the rocking mechanism. Since the swing fulcrum 30aY is arranged so that the angle formed by the direction A2 of the developer carrying member cleaning blade 21Y and the gravity line G becomes small when moved, the liquid deposited on the surface of the developer carrying member cleaning blade 21Y. The developer can be easily dropped by gravity, and the liquid developer on the surface of the developer carrying member cleaning blade 21Y can be reduced. In addition, it is not necessary to add new members or change the configuration significantly, and the apparatus can be easily downsized.

  In addition, since the developer carrier 20Y is provided with a rocking fulcrum so as to be pressed against the latent image carrier 10Y in the escape direction, the toner on the latent image carrier 10Y is more than the press-rotated in the biting direction. The influence on the layer can be reduced.

  Further, since the developer carrier 20Y is rotated in a state where the developer carrier 20Y is separated from the latent image carrier 10Y, the developer carrier 20Y is not developed on the developer carrier 20Y without developing the liquid developer on the latent image carrier 10Y. This liquid developer can be cleaned by the developer carrier cleaning blade 21Y and dropped by gravity, so that unnecessary liquid developer does not need to adhere to the latent image carrier 10Y.

  In addition, it has a developer supply member 32Y for supplying a liquid developer to the developer carrier 20Y and a developer regulating blade 33Y for regulating the amount of the liquid developer on the developer supply member 32Y, and has a swing mechanism. Therefore, when the developer carrying body 20Y is swung to a position separated from the latent image carrying body 10Y, the rocking fulcrum 30aY is arranged so that the angle formed by the direction A3 of the developer regulating blade 33Y and the horizontal line H becomes small. Therefore, the liquid developer remaining in the vicinity of the developer regulating blade 33Y during non-image formation can be reduced, the clogging of the developer supply member 32Y can be reduced, and the supply amount can be quantified.

  Further, the developer compression device 22Y that compresses the toner of the liquid developer on the developer carrier 20Y is provided, and when the developer carrier 20Y is swung to a position separated from the latent image carrier 10Y by the swing mechanism. Since the swing fulcrum 30aY is arranged so that the angle formed by the surface A4 of the developer compressing device 22Y and the gravitational line is small, contamination of the developer compressing device 22Y with the liquid developer can be reduced.

  Further, the image forming apparatus of the present embodiment exposes the latent image carrier 10Y, the latent image carrier 10Y that develops the latent image by the developer carrier 20Y, the charger 11Y that charges the latent image carrier 10Y, and the latent image carrier 10Y. Since the exposure device 12Y and the transfer member 40Y for transferring the image on the latent image carrier 10Y are provided, an image can be formed with good image quality.

  Further, the developer container 31Y for storing the liquid developer and squeeze devices 13Y and 14Y for removing excess liquid developer from the liquid developer on the latent image carrier 10Y are provided, and the squeeze devices 13Y and 14Y. The liquid developer removed in this manner is dropped on the developer carrier cleaning blade 21Y, and the liquid developer dropped on the developer carrier cleaning blade 21Y and the liquid developer cleaned by the developer carrier cleaning blade 21Y are developed. Since the liquid developer on the surface of the developer carrying member cleaning blade 21Y easily flows because it is dropped into the agent container 31Y, and no additional member is required, the apparatus can be reduced in size and cost can be reduced.

1 is a diagram illustrating an embodiment of an image forming apparatus. FIG. 3 is a cross-sectional view showing the main components of the periphery of the latent image carrier and the developing unit. It is a perspective view of a developer supply member. It is a figure explaining compression of the developer by a developer compression device. It is a figure explaining development by a development roller. It is a figure explaining the squeeze effect | action by a squeeze roller. FIG. 4 is a diagram showing a developing unit in contact with a latent image carrier. FIG. 4 is a diagram showing a developing unit in contact with a latent image carrier. It is a figure which shows the developing unit of a separation state with respect to a latent image carrier. It is a figure which shows the liquid developer removed by the squeeze apparatus.

Explanation of symbols

  10Y, 10M, 10C, 10K ... photosensitive body (latent image carrier), 11Y, 11M, 11C, 11K ... charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y ... first squeeze device, 13aY ... first Squeeze roller, 13bY ... first squeeze roller cleaning blade, 14Y ... second squeeze device, 14aY ... second squeeze roller, 14bY ... second squeeze roller cleaning blade, 16Y ... static eliminator, 17Y ... latent image carrier blade, 18Y ... Latent image carrier cleaning liquid recovery unit, 20Y, 20M, 20C, 20K ... developing roller (developer carrier), 21Y ... developing roller cleaning blade (developer carrier cleaning blade), 22Y ... developer compressor, 30Y, 30M, 30C, 30K ... developing unit (developing device , 31Y, 31M, 31C, 31K ... developer container, 31aY ... collection unit, 31bY ... supply unit, 32Y, 32M, 32C, 32K ... developer supply roller (developer supply member), 33Y ... developer regulating blade, 34Y ... Recovery screw, 35Y ... Communication part, 36Y ... Stir paddle (stirring member), 50Y, 50M, 50C, 50K ... Primary transfer backup roller, 40 ... Intermediate transfer belt (intermediate transfer member), 41 ... Belt drive roller, 42 ... Tension roller 46 ... Intermediate transfer belt cleaning blade 47 ... Intermediate transfer belt cleaning liquid recovery unit 50 ... Primary transfer unit 51 ... Primary transfer roller 60 ... Secondary transfer unit 61 ... Secondary transfer roller 62 ... Secondary Secondary transfer roller blade, 63 ... secondary transfer roller cleaning liquid recovery unit, 70Y ... developer recovery and supply device, 71Y ... Liquid developer reservoir, 72Y ... Development unit recovery path, 73Y ... Latent image carrier recovery path, 74Y ... Developer tank, 75Y ... Developer supply path, 76Y ... Developer pump, 77Y ... Carrier liquid tank, 78Y ... Carrier liquid supply path, 79Y ... Carrier liquid pump, 81Y ... Developer supply path, 82Y ... Developer supply pump,

Claims (7)

A developer carrying member carrying a liquid developer; a developer carrying member cleaning blade for cleaning the liquid developer on the developer carrying member; and contacting and separating the developer carrying member from a latent image carrying member. A swinging mechanism that moves the developer carrier to a position spaced apart from the latent image carrier by the swing mechanism, and the direction and gravity of the developer carrier cleaning blade A developing device in which a swing fulcrum is arranged so that an angle formed with a line is small. 2. The developing device according to claim 1, wherein the developer carrying member is provided with a rocking fulcrum so as to be pressed against the latent image carrying member in a relief direction.   The developing device according to claim 1, wherein the developer carrying member is rotated in a state where the developer carrying member is separated from the latent image carrying member. A developer supply member that supplies a liquid developer to the developer carrying member; and a developer restriction member that restricts the amount of the liquid developer on the developer supply member. The rocking fulcrum is arranged so that an angle formed by the direction of the developer regulating member and a horizontal line becomes small when the agent carrier is swung to a position separated from the latent image carrier. The developing device according to claim 1. A developer compression device for compressing the toner of the liquid developer on the developer carrier, and when the developer carrier is swung to a position spaced apart from the latent image carrier by the rocking mechanism, 5. The developing device according to claim 1, wherein a swing fulcrum is arranged so that an angle formed between the surface of the developer compressing device and a gravitational line becomes small.   A latent image carrier that develops a latent image by the developer carrier, a charger that charges the latent image carrier, an exposure device that exposes the latent image carrier, and an image on the latent image carrier An image forming apparatus using the developing device according to claim 1, further comprising: a transfer member that transfers the toner. A developer container for storing the liquid developer, and a squeeze device for removing excess liquid developer from the liquid developer on the latent image carrier, and the liquid developer removed by the squeeze device is The liquid developer dropped on the developer carrier cleaning blade and dropped on the developer carrier cleaning blade and the liquid developer cleaned by the developer carrier cleaning blade are dropped on the developer container. The image forming apparatus according to claim 6.

Images