JP2006184593A - Liquid developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid developing device in which a liquid developer carrier can be detached from a latent image carrier even if a power source turns off and the plastic deformation of the liquid developer carrier can be thereby surely prevented. <P>SOLUTION: The liquid developing device 50 is equipped with a developing roller 52 which supplies the liquid developer to a photoreceptor drum 20 and has at least a surface composed of an elastic body. The device is equipped with a first attaching/detaching mechanism S1 which brings the developing roller 52 into contact with the photoreceptor drum 20 and detaches the developing roller from the photoreceptor drum 20 while not in development and while the power source is off. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid developing device employed in a copying machine, a facsimile machine, a printer, and the like.

  Conventionally, a liquid developing device develops an electrostatic latent image formed on a latent image carrier such as a photosensitive member (for example, a photosensitive drum) with a liquid developer in which toner is dispersed in an insulating liquid. I have to. That is, the liquid developing device includes a liquid developer carrier such as a developing roller, an anilox roller (supply roller) for applying the liquid developer to the liquid developer carrier in a thin layer, and a liquid developer on the anilox roller. A doctor blade for regulating the amount of developer, a developer storage tank for storing a liquid developer, and the like. The liquid developer pumped up from the developer storage tank is supplied to the anilox roller, and after the amount of the liquid developer on the anilox roller is regulated by the doctor blade, the liquid developer is thinned to the liquid developer carrier. Applied. The liquid developer carrier supplies the thinned liquid developer to the latent image carrier, and develops the electrostatic latent image formed on the latent image carrier with the supplied liquid developer.

  By the way, the liquid developer carrying member is made of an elastic body, and at the time of development, the liquid developer is supplied to the latent image surface on the latent image carrying member by contacting the latent image carrying member. . Thus, making the thickness of the thin layer of the liquid developer supplied to the liquid developer carrying member uniform is an important factor for making the image density uniform.

Therefore, it is preferable that the elastic liquid developer carrier is separated during non-development so that the elastic liquid developer carrier is not plastically deformed.
By the way, as a technique for preventing plastic deformation of the elastic body, the contact means driven by the driving source at the time of development in the power-on state makes the elastic body application roller contact the developing belt and is driven at the time of non-development in the power-on state. There has been proposed a technique in which a separating means driven by a source separates an elastic body application roller from a developing belt (Patent Document 1).

  According to the technique of Patent Document 1, a liquid developer carrying member such as a developing roller is formed of an elastic body, and the liquid developer carrying member is a liquid that supplies liquid developer to a latent image carrier such as a photosensitive drum. It can be considered to be applied to a developing device.

As described above, in the liquid developing device to which the technique of Patent Document 1 is applied, during the development, the separation / contact means driven by the driving source contacts the elastic liquid developer carrier with the latent image carrier. It becomes the composition made to do. In addition, according to this liquid developing device, during non-development, the separating means driven by the driving source separates the elastic liquid developer carrier from the latent image carrier, thereby developing the liquid developer. The deformation of the agent carrier can be prevented.
JP-A-8-137278

  However, in this configuration, since the liquid developer carrier is separated from the latent image carrier in the power-on state, the elastic liquid developer carrier is in contact with the latent image carrier. When the power is turned off, the elastic liquid developer carrier is left in contact with the latent image carrier, and the elastic liquid developer carrier may be plastically deformed. Due to this plastic deformation, a uniform liquid developer film cannot be formed on the elastic liquid developer carrier, and as a result, the uniform liquid developer cannot be supplied to the latent image carrier. It can be a cause of defects.

  The object of the present invention is to allow the liquid developer carrier to be separated from the latent image carrier even when the power is turned off as described above, thereby ensuring plastic deformation of the liquid developer carrier. It is an object of the present invention to provide a liquid developing apparatus that can prevent the above. Another object of the present invention is to provide a liquid developing apparatus capable of suppressing the consumption of useless liquid developer.

  In order to solve the above-mentioned problems, the invention according to claim 1 supplies a liquid developer to a latent image carrier on which an electrostatic latent image is formed, and at least a liquid developer carrier having a surface made of an elastic body. In a liquid developing apparatus having a body, a first contact / separation mechanism for bringing the liquid developer carrier into contact with the latent image carrier during development and separating the liquid developer carrier from the latent image carrier during non-development and power-off. The gist of the liquid developing device is provided.

  According to a second aspect of the present invention, in the first aspect, the apparatus further comprises a supply roller for supplying a liquid developer to the liquid developer carrier, and the first contact / separation mechanism supplies the liquid developer carrier at the time of development. It is a mechanism that is brought into contact with a roller and is separated from the supply roller when not developed and when the power is turned off.

  According to a third aspect of the present invention, there is provided a cleaning means for cleaning the surface of the liquid developer carrying member according to the first or second aspect. A second contact / separation mechanism for separating from the liquid developer carrying member is provided at the time and when the power is turned off.

  According to a fourth aspect of the present invention, in the first aspect, the first contact / separation mechanism includes a first sun gear provided on a rotation shaft of a supply roller that supplies the liquid developer to the liquid developer carrier, and the first sun gear. A first differential gear mechanism that includes a first planetary gear that is meshed with one sun gear and that is provided on a rotation shaft of the liquid developer carrier, and that separates the liquid developer carrier from the latent image carrier. First biasing means for biasing in the direction is included.

  According to a fifth aspect of the present invention, in the third aspect, the second contact / separation mechanism includes a second sun gear provided on a rotation shaft of a supply roller that supplies the liquid developer to the liquid developer carrier, and the second sun gear. A second differential gear mechanism that includes a second planetary gear that is meshed with the two sun gears and that is provided on a support unit that supports the cleaning unit; and the cleaning unit is moved away from the liquid developer carrier. Second biasing means for biasing is included.

  According to the first aspect of the present invention, at the time of non-development and when the power is turned off, the liquid developer carrying member is separated from the latent image carrier by the first contact / separation mechanism. Plastic deformation of the surface of the carrier can be prevented.

  In general, since a surface potential is applied to the latent image carrier for development at the time of development, the latent image carrier is in a state where the liquid developer carrier is in contact with the latent image carrier at the start of development. Is rotated, the liquid developer remaining on the liquid developer carrier is supplied to the area where the latent image is not formed on the latent image carrier, and then the cleaning device for cleaning the latent image carrier, It is cleaned and wasted.

  On the other hand, in the first aspect of the invention, since the developer carrier is not in contact with the latent image carrier yet at the start of development, the liquid development remaining on the developer carrier The agent is not supplied to the latent image carrier and is not wasted by a cleaning device that cleans the latent image carrier.

  Conventionally, the latent image carrier is driven to rotate later than the other members at the time of non-development immediately after the end of development, so that the liquid developer carrier is in contact even after the end of development. Therefore, useless liquid developer is physically supplied to the latent image carrier.

  On the other hand, in the first aspect of the invention, even during non-development immediately after the end of development, the latent image carrier is applied with a voltage for development until later than the other members and is driven to rotate. However, after the development is completed, the liquid developer carrier is not in contact with the liquid developer, so that useless liquid developer is not supplied to the latent image carrier.

  According to the second aspect of the present invention, the liquid developer carrier is separated from the supply roller by the first contact / separation mechanism at the time of non-development and when the power is turned off. As a result, plastic deformation of the liquid developer carrying member is eliminated, and plastic deformation can be prevented.

  According to the invention of claim 3, since the cleaning means is separated from the liquid developer carrying member by the second contact / separation mechanism at the time of non-development and power off, the cleaning means abuts at the time of non-development and power off. As a result, plastic deformation of the liquid developer carrying member is eliminated, and plastic deformation can be prevented.

  According to the fourth aspect of the present invention, the first contact / separation mechanism includes the first differential gear mechanism provided on the liquid developer carrier and the supply roller, and the liquid developer carrier in the direction away from the latent image carrier. By including the first urging means for urging, the effect of the invention of claim 1 can be easily realized.

  According to the fifth aspect of the present invention, the second contact / separation mechanism includes the second differential gear mechanism provided in the liquid developer carrier and the cleaning unit, and the cleaning unit is urged away from the liquid developer carrier. By adopting a configuration including the second urging means, the effect of the invention of claim 3 can be easily realized.

(First embodiment)
Hereinafter, a first embodiment embodying a liquid developing device of the present invention will be described with reference to FIGS. The liquid developing device 50 can be used in a liquid image forming apparatus such as a copying machine, a facsimile machine, or a printer.

  The liquid developing device 50 is formed on the surface of the photosensitive drum 20 by exposure with an exposure device (not shown), for example, by transferring the liquid developer to the surface of the photosensitive drum 20 as a latent image carrier. The developed electrostatic latent image is developed. That is, the liquid developing device 50 stirs and mixes a liquid developer composed of toner and a liquid carrier so as to have a predetermined concentration, and the developer is used by the developing roller 52 as a liquid developer carrying member. The toner image is formed on the photosensitive drum 20 by applying to the electrostatic latent image. The toner image obtained by developing the electrostatic latent image formed as described above is transferred to paper or an intermediate transfer member (both not shown) as a recording medium.

  In the container 51 (see FIG. 3), the liquid developing device 50 includes a developing roller 52 whose surface is formed of an elastic body, an anilox roller 53 as a supply roller, a pumping roller 54, a doctor blade 55, A cleaning blade 56 is provided as a cleaning means. The developing roller 52 only needs to have a surface formed of at least an elastic body.

As shown in FIG. 3, the rotating shaft 20 a of the photosensitive drum 20 is rotatably supported with respect to the side wall 51 a of the storage container 51.
Similarly, the anilox roller 53 and the pump-up roller 54 are rotatably supported so that the rotation shafts 53 a and 54 a are rotatable with respect to both side walls 51 a that are spaced apart in the longitudinal direction of the container 51. In FIG. 3, only one side wall 51a is shown.

  As shown in FIG. 4, the side wall 51a is formed with an arc-shaped long hole 51b having a radius of curvature around the axis O of the rotation shaft 53a of the anilox roller 53, and the long hole 51b is developed. The rotating shaft 52a of the roller 52 is penetrated and supported so as to be movable along the shape of the elongated hole 51b. Moreover, the movement range of the rotating shaft 52a is regulated at both ends in the longitudinal direction of the long hole 51b.

  In the present embodiment, as shown in FIG. 4, when the rotation shaft 52 a is locked to one end of the long hole 51 b, the developing roller 52 is referred to as a contact position P <b> 0 that contacts the photosensitive drum 20. Further, when the rotation shaft 52a is locked to the other end of the long hole 51b, the developing roller 52 is referred to as a separation position P1 at which it is separated from the photosensitive drum 20. In this way, the rotation shaft 52a of the developing roller 52 can draw an arc-shaped movement locus around the axis of the rotation shaft 53a.

  Gears 72, 73, and 74 are fixed to the rotary shafts 52a, 53a, and 54a protruding from the container 51, and a gear train that meshes with adjacent gears is formed by these gears.

  The gear 72 fixed to the rotation shaft 52a of the developing roller 52 is always meshed with the gear 73 regardless of the position of the rotation shaft 52a between the contact position P0 and the separation position P1. Yes.

  The drive transmission joint 80 is connected to the rotation shaft 53a, and can transmit the rotation torque of a drive motor (not shown) to the rotation shaft 53a. The torque transmission system from the drive motor to the gears 72 to 74 constitutes one drive transmission system. Further, on the outer side of the side wall 51a, the rotating shafts 52a and 53a are pivotally penetrated and attached to the plate-like connecting member 65, as shown in FIG. 1 (c) and FIG. .

  In the present embodiment, the gear 73 corresponds to a first sun gear, and the gear 72 corresponds to a first planetary gear. The connecting member 65 and the gears 72 and 73 constitute a first differential gear mechanism that is a planetary gear mechanism.

  The developing roller 52, the anilox roller 53, and the scooping roller 54 are rotationally driven by a drive motor (not shown) through the gears 72, 73, 74 and the drive transmission joint 80. A gear 71 is fixed to the rotating shaft 20a of the photosensitive drum 20, and the gear 71 is rotationally driven by a drive transmission system different from the drive transmission system including the gears 72 to 74. The

  The cleaning blade 56 is formed from a rubber or metal blade-like member. As shown in FIG. 3, the cleaning blade 56 is supported so as to be rotatable with respect to the rotation shaft 52 a via a bracket 60, and the developing roller 52 is opposed to the surface (that is, the peripheral surface) of the developing roller 52. The surface of the developing roller 52 is cleaned by always abutting in the counter direction with respect to the rotation direction of the developing roller 52. 1A, 1B, 2A, and 2B, only a portion of the bracket 60 that is attached to the rotating shaft 52a of the bracket 60 is illustrated, and the cleaning blade 56 is attached. These portions are not shown for convenience of explanation.

  One end of a tension coil spring 82 as first urging means is fixed to the bracket 60. The other end of the tension coil spring 82 is fixed to the wall surface of the container 51. The developing roller 52 is urged away from the photosensitive drum 20 by the elastic force (that is, urging force) of the tension coil spring 82 via the rotating shaft 52a. This urging force is adjusted so as not to prevent the circumferential movement of the gear 72 relative to the gear 73 when the gears 72, 73, 74 are rotationally driven by the drive motor.

  Accordingly, when the photosensitive drum 20, the developing roller 52, the anilox roller 53, and the scooping roller 54 are rotationally driven by a drive motor (not shown) through the gears 72, 73, 74 and the drive transmission joint 80, The developing roller 52 is movable to the photosensitive drum 20 side.

  A first contact / separation mechanism S1 is configured by using the tension coil spring 82 as the first biasing means and the connecting member 65 and the gears 72 and 73 as the first differential gear mechanism. The connecting member 65 may be omitted. In this case, the side wall 51a having the long hole 51b and the gears 72 and 73 are used as the first differential gear mechanism.

  The doctor blade 55 is attached to the side wall 51 a via a bracket (not shown), and the tip thereof is in contact with the rotation direction of the anilox roller 53 in the counter direction.

  Although not shown, the liquid developer stored in the lower portion of the container 51 is adjusted so that the toner is dispersed at a high concentration in a carrier liquid made of a nonpolar insulating liquid such as silicone oil. The pumping roller 54 is partially immersed in the liquid developer, and is not shown in FIG. 1, but is spaced apart from the anilox roller 53 so as to have a minute gap. The pumped liquid developer is applied to the anilox roller 53.

  The liquid developer pumped up by the pump-up roller 54 is transferred to the anilox roller 53, and the liquid developer on the surface of the anilox roller 53 is regulated (measured) by the doctor blade 55 and then developed. The roller 52 is supplied.

  The anilox roller 53 applies a liquid developer onto the developing roller 52 to form a thin layer of the liquid developer on the developing roller 52. In the developing area on the photosensitive drum 20, the latent image is developed by the liquid developer. Further, after the development, the liquid developer remaining on the developing roller 52 is removed from the developing roller 52 by the edge portion of the cleaning blade 56 in contact with the surface of the developing roller 52. On the other hand, the toner image developed on the photosensitive drum 20 is transferred to paper or an intermediate transfer body (both not shown). On the photosensitive drum 20, a part of the liquid developer remains in an untransferred state and is removed by a cleaning device (not shown).

Now, the operation of the liquid developing device 50 configured as described above will be described.
In the liquid developing device 50, when the power of the liquid developing device 50 is off, a drive motor (not shown) is stopped, and the rotary shaft 52a is separated from the separation position P1 by the tension coil spring 82 via the bracket 60 and the rotary shaft 52a. The developing roller 52 is separated from the photosensitive drum 20 (see FIG. 2). In this state, since the developing roller 52 is not in contact with the photosensitive drum 20, when the power is turned off, plastic deformation of the surface of the developing roller 52 is prevented.

  When the power of the liquid developing device 50 is turned on and development occurs, the surface potential (that is, dark potential) is applied to the photosensitive drum 20 by a main charging device (not shown) so as to be a predetermined voltage. It is rotationally driven via a drive transmission system different from the drive transmission system for driving the rollers. Thereafter, a developing bias (for example, 250 V) lower than the surface potential is applied to the developing roller 52.

  Thereafter, a drive motor (not shown) is turned on. By driving the drive motor, the rollers and the photosensitive drum 20 are rotationally driven through the drive transmission joint 80 and the gears 72 to 74. By this rotation, the gear 72 moves from the separation position P1 to the contact position P0, and the developing roller 52 is brought into contact with the photosensitive drum 20 (see FIGS. 1A and 1B).

  Then, a developing electric field is generated between the developing roller 52 and the image portion (that is, the bright potential portion) of the photosensitive drum 20 where the surface of the photosensitive drum 20 is exposed by an exposure device (not shown) and has a bright potential of, for example, 20V. As a result, the toner charged to the positive potential of the liquid developer moves from the developing roller 52 to the photosensitive drum 20. On the other hand, in the photosensitive drum 20, the non-image portion (that is, the dark potential portion) that is not exposed is an electric field formed by the dark potential and the developing bias, and the toner particles do not adhere.

In this way, each roller and the photosensitive drum 20 are rotationally driven, and the latent image on the photosensitive drum 20 is developed.
When the development is completed (that is, when non-development is performed), or when the power is turned off during development (when the power is turned off), the drive motor (not shown) is stopped. The rotating shaft 52a is moved to the separation position P1 by the urging force. As a result, the developing roller 52 is pulled by the tension coil spring 82 via the bracket 60 and the rotating shaft 52a, and is separated from the photosensitive drum 20 (see FIGS. 2A and 2B).

  In this way, in the first embodiment, the tension coil spring 82 is used as the first biasing means, and the connecting member 65 and the gears 72 and 73 are used as the first differential gear mechanism, so that the developing is performed when the power is turned off. The roller 52 can be separated from the photosensitive drum 20. As a result, since the developing roller 52 does not come into contact with the photosensitive drum 20 when the power is off or during non-development, plastic deformation of the elastic body on the surface of the developing roller 52 can be prevented.

  In the first embodiment, at the start of development, the photosensitive drum 20 is driven to rotate while being applied with a dark potential (applied voltage) for development. At the start of development, since the developing roller 52 is not yet in contact with the photosensitive drum 20, even if the photosensitive drum 20 rotates, the liquid developer remaining on the developing roller 52 is removed from the photosensitive drum. It is not supplied to the drum 20 and is not cleaned unnecessarily by the cleaning device (not shown).

  In the first embodiment, even during non-development immediately after completion of development, the photosensitive drum 20 is applied with a surface potential for development until later than the other rollers, and even after being driven to rotate, after completion of development. In this case, since the developing roller 52 is not in contact with the photosensitive drum 20, useless liquid developer is not supplied to the photosensitive drum 20.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In addition, about the same structure as 1st Embodiment, the same code | symbol is attached | subjected, the description is abbreviate | omitted, and it demonstrates centering on a different structure.

  In the second embodiment, the connecting member 65 is omitted in the configuration of the first embodiment. Instead, as shown in FIG. 6, the shape of the long hole 51b of the side wall 51a of the storage container 51 is different as follows. The other members are different in configuration.

  That is, in the first embodiment, the long hole 51b forms an arc-shaped long hole 51b having a radius of curvature with the axis O of the rotation shaft 53a of the anilox roller 53 as a center. The rotation shaft 52a is configured to draw an arcuate movement locus A around the axis of the rotation shaft 53a (see FIGS. 5 and 6).

  In the second embodiment, the shape of the long hole 51b is formed in an arc shape or a linear shape, and the movement locus B of the rotating shaft 52a is formed in an arc shape or a linear shape. And the position of the end of the long hole 51b is set so that it may become the same position as 1st Embodiment, when the rotating shaft 52a is located in the contact position P0. Further, the position of the other end of the long hole 51b is such that when the rotation shaft 52a is located at the separation position P1, the separation distance from the axis O of the rotation shaft 53a is longer than in the first embodiment. Is set. Further, as shown in FIG. 6, the position of the other end of the long hole 51b is such that when the rotation shaft 52a is located at the separation position P1, the cutting edge circle of the gear 72 of the rotation shaft 52a is the gear of the rotation shaft 53a. The position intersects with the cutting edge circle 73, that is, the position where the meshing relationship between the gears 72 and 73 is established. As a result, in the first differential gear mechanism, the gear 72 is engaged with the gear 73 even when the power is turned on, and the rotating shaft 52a is located at the contact position P0 from the separation position P1. Have been able to.

  In the second embodiment, the tension coil spring 82 is the first biasing means, and the side wall 51a having the long hole 51b and the gears 72 and 73 are the first differential gear mechanism, so that the first contact / separation mechanism S1 is It is configured.

  Thus, by setting the shape of the long hole 51b to be an arc or a straight line, the long hole 51b allows the rotation shaft 52a to move between both end portions in the longitudinal direction, and the rotation shaft 52a. However, the developing roller 52 is separated from the anilox roller 53 when positioned at the separation position P1.

  In the second embodiment, when the rotation shaft 52 a is located at the separation position P <b> 1, the developing roller 52 can be separated from the photosensitive drum 20 and can be separated from the anilox roller 53. As a result, the same effects as those of the first embodiment can be obtained, and further, since the non-development and the power off, the anilox roller 53 is not contacted, so that the surface of the developing roller 52 is not plastically deformed, thereby preventing plastic deformation. it can.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. In the third embodiment, the structure related to the cleaning blade 56 is different in the configuration of the second embodiment, and the other configurations are the same. Therefore, the structure related to the different cleaning blade 56 will be described and the same as the configuration of the second embodiment. The same reference numerals are given to the configurations. For convenience of explanation, the third embodiment also includes the first contact / separation mechanism S1 including the first differential gear mechanism as the first urging means described in the second embodiment. 10 are omitted. 7 and 9, for convenience of explanation, the anilox roller 53 and the pumping roller 54 are not shown, but the anilox roller 53 and the pumping roller 54 have the same configuration as in the second embodiment.

  The cleaning blade 56 is supported with respect to the storage container 51 via a support mechanism 90 as a support means. The support mechanism 90 includes a bracket 62 to which the cleaning blade 56 is attached, and a support arm 92. The bracket 62 is disposed in parallel to the developing roller 52, and both end surfaces of the base end portion of the bracket 62 are rotatably supported by a pair of support arms 92 (FIGS. 9 and 9). 10 shows only one support arm 92). The support arm 92 is bent in an L shape at the distal end side, and the distal end portion is supported so as to be rotatable in the vertical direction with respect to the storage container 51. The cleaning blade 56 is attached to the bracket 62, and the tip thereof is always in contact with the developing roller 52 in the counter direction with respect to the rotation direction of the developing roller 52 as shown in FIG. To clean. A position where the cleaning blade 56 is in contact with the developing roller 52 is referred to as a cleaning position.

  A pair of fixed shafts 77 project from both end faces of the bracket 62 (only one is shown in FIGS. 7 and 8). A gear 76 is rotatably supported on the fixed shaft 77. As shown in FIG. 7, the connecting member 78 has a fixed shaft 77 and a rotating shaft 53a penetrated so as to be relatively rotatable. A gear 75 is fixed to the rotary shaft 53 a between the gear 73 and the anilox roller 53. The gear 76 is always meshed with the gear 75 by the connecting member 78.

  In the third embodiment, the gear 75 corresponds to a second sun gear, and the gear 76 corresponds to a second planetary gear. The connecting member 78 and the gears 75 and 76 constitute a second differential gear mechanism that is a planetary gear mechanism.

  Further, as shown in FIGS. 7 and 8, one end of a tension coil spring 94 as second urging means is fixed to the base end of the bracket 62. The other end of the tension coil spring 94 is fixed to the wall surface of the container 51. The cleaning blade 56 is urged away from the developing roller 52 via the bracket 62 by the elastic force (that is, urging force) of the tension coil spring 94. The urging force is adjusted so as not to prevent the gear 76 from moving in the circumferential direction with respect to the gear 75 when the gears 75 and 76 are rotationally driven by the drive motor. Further, the urging force of the tension coil spring 94 allows the cleaning blade 56 to be positioned at a cleaning release position that separates the cleaning blade 56 from the developing roller 52 as shown in FIGS. This cleaning release position is set when a stopper (not shown) provided in the storage container 51 is engaged with the support arm 92.

  Now, the operation of the liquid developing device 50 configured as described above will be described. In the third embodiment, the operation of the first contact / separation mechanism S1 at the time of development, non-development, and power-off is the same as that of the second embodiment, so the description is omitted and the second contact / separation mechanism S2 is omitted. A description will be given focusing on the above.

  In the liquid developing device 50, when the power of the liquid developing device 50 is off, the drive motor (not shown) is stopped, and the cleaning blade 56 is separated from the developing roller 52 via the bracket 62 by the tension coil spring 94. It is located at (cleaning release position) (see FIGS. 9 and 10). In this state, since the cleaning blade 56 is not in contact with the developing roller 52, plastic deformation of the surface of the developing roller 52 by the cleaning blade 56 is prevented when the power is turned off.

  When the power of the liquid developing device 50 is turned on and development is in progress, a drive motor (not shown) is turned on. By driving the drive motor, each roller and the photosensitive drum 20 are rotationally driven through a drive transmission joint 80 (not shown in FIGS. 8 and 10) and gears 72 to 74. At the same time, the gears 75 and 76 rotate. As a result of this rotation, the gear 76 rotates and moves from the position shown in FIG. 9 to the position shown in FIG. 7, and the cleaning blade 56 is positioned at the cleaning position where it contacts the developing roller 52 (see FIGS. 7 and 8). .

  Further, when the power is turned off during non-development or development, the drive motor (not shown) is stopped, so that the gear 76 rotates around the gear 75 by the urging force of the tension coil spring 94. The cleaning blade 56 is moved from the cleaning position to the cleaning release position via the bracket 62. As a result, the cleaning blade 56 is separated from the developing roller 52.

  Thus, in the third embodiment, the tension coil spring 94 is used as the second urging means, and the connecting member 78 and the gears 75 and 76 are used as the second differential gear mechanism, so that the cleaning can be performed when the power is turned off. The blade 56 can be separated from the developing roller 52. As a result, the cleaning blade 56 does not come into contact with the developing roller 52 when the power is off or during non-development, so that the elastic deformation of the elastic body on the surface of the developing roller 52 can be prevented.

  In addition, this invention is not limited to the said embodiment, For example, you may replace with the cleaning roller instead of the cleaning blade 56 as a cleaning means. The latent image carrier may be a photosensitive belt instead of the photosensitive drum 20.

(A) is the schematic of the liquid developing device of 1st Embodiment which actualized this invention, (b) is explanatory drawing which shows the position of the developing roller at the time of image development, (c) is explanatory drawing of a differential gear mechanism. (A), (b) is explanatory drawing of an effect | action of a liquid image forming apparatus similarly. Explanatory drawing which similarly shows the principal part of a liquid developing device. FIG. 6 is an explanatory diagram of a support structure for the developing roller 52 with respect to a side wall 51 a of the container 51. Explanatory drawing of the principal part of the liquid developing device of 2nd Embodiment. Similarly explanatory drawing of a differential gear mechanism. Explanatory drawing of the principal part of the liquid developing device of 3rd Embodiment. The principal part perspective view of a liquid developing device. FIG. 6 is a main part explanatory view for explaining the operation of the liquid developing device. The principal part perspective view of a liquid developing device.

Explanation of symbols

20 ... Photosensitive drum (latent image carrier)
50 ... Liquid developing device 52 ... Developing roller (liquid developer carrier)
53. Anilox roller (supply roller)
56 ... Cleaning blade (cleaning means)
72 ... Gear (first planetary gear)
73 ... Gear (first sun gear)
75 ... Gear (second sun gear)
76 ... Gear (second planetary gear)
82 ... Tensile coil spring (first biasing means)
90 ... Support mechanism (support means)
94 ... Tensile coil spring (second biasing means)
S1 ... First contact / separation mechanism S2 ... Second contact / separation mechanism

Claims (5)

In a liquid developing apparatus provided with a liquid developer carrying member having at least a surface made of an elastic body while supplying a liquid developer to the latent image carrying member on which the electrostatic latent image is formed,
A liquid developing device comprising a first contact / separation mechanism for bringing the liquid developer carrier into contact with the latent image carrier at the time of development, and separating the latent image carrier from the latent image carrier at the time of non-development and power off. apparatus. A supply roller for supplying a liquid developer to the liquid developer carrier;
The first contact / separation mechanism causes the liquid developer carrier to contact the supply roller during development, and separates from the supply roller during non-development and when the power is off. Liquid developing device. A cleaning means for cleaning the surface of the liquid developer carrying member;
2. A second contact / separation mechanism that contacts the liquid developer carrier during development and separates from the liquid developer carrier during non-development and when the power is turned off. Alternatively, the liquid developing device according to claim 2.   The first contact / separation mechanism is meshed with the first sun gear provided on a rotation shaft of a supply roller for supplying the liquid developer to the liquid developer carrying member, and the liquid developer. A first differential gear mechanism including a first planetary gear provided on a rotation shaft of the carrier, and first biasing means for biasing the liquid developer carrier in a direction away from the latent image carrier. The liquid developing device according to claim 1.   The second contact / separation mechanism is meshed with a second sun gear provided on a rotation shaft of a supply roller for supplying the liquid developer to the liquid developer carrier, and the cleaning means. A second differential gear mechanism including a second planetary gear provided on a supporting means for supporting the second developer gear, and a second urging means for urging the cleaning means in a direction away from the liquid developer carrier. 4. The liquid developing apparatus according to claim 3, wherein

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