JP4420880B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus provided with a developing means such as a developing roller that comes into contact with an image carrier such as a photosensitive drum charged to a predetermined potential and supplies a liquid developer to the image carrier. The present invention relates to a technique for preventing waste of liquid developer due to unnecessary supply of liquid developer from the developing means to the image carrier.

A so-called wet image forming apparatus represented by a copying machine or a printer apparatus that forms an image using a liquid developer contacts a photosensitive drum charged to a predetermined potential by a charging device, and contacts the photosensitive drum. A developing device including a developing roller that supplies a liquid developer and a supply roller that supplies the liquid developer to the developing roller is disposed. In the image forming apparatus configured as described above, since the photosensitive drum and the developing roller are in contact with each other, liquid developer is applied to the developing roller even if the photosensitive drum is not charged to a predetermined potential. If adhered, the liquid developer may be supplied to the photosensitive drum. The supply of the liquid developer to the portion that is not charged to the predetermined potential is essentially unnecessary and wastes the liquid developer.
On the other hand, in Patent Document 1, while supplying developer to the photosensitive drum is unnecessary (before image formation, etc.), the supply of the developer to the photosensitive drum is stopped by stopping the driving of the developing roller. Has been proposed. Further, by using the mechanism for separating the developing roller from the photosensitive drum shown in Patent Document 2, the supply of the developer to the photosensitive drum is prevented while the supply of the developer to the photosensitive drum is unnecessary. Is also possible.
JP-A-5-173410 JP 2002-287516 A

However, in the configuration in which the driving of the developing roller is stopped as in the technique disclosed in Patent Document 1, since the photosensitive drum is driven in contact with the stopped developing roller, the developing roller, the photosensitive drum, There is a problem that the photosensitive drum is damaged by sliding. On the other hand, in the configuration in which the developing roller is separated from the photosensitive drum, the developing roller repeatedly moves, so that the positional relationship between the developing roller and the photosensitive drum is likely to be displaced, and the development performance is deteriorated due to this positional displacement. Arise.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to prevent unnecessary supply of the liquid developer to the image carrier and prevent waste of the liquid developer. Another object of the present invention is to provide an image forming apparatus capable of preventing the development performance from being deteriorated due to the damage of the image carrier and the displacement of the developing means (developing roller or the like).

In order to achieve the above object, the present invention provides a charging means for charging an image carrier to a predetermined potential, and the image carrier charged to a predetermined potential by the charging means and contacting the image carrier with a liquid. An image forming apparatus comprising: a developing unit that supplies a developer; and a developer supplying unit that supplies the liquid developer to the developing unit. The charging unit and the developing unit are configured to rotate the image carrier. The distance from the charging position by the charging unit to the developing position by the developing unit on the image carrier viewed in the direction is from the contact position with the developer supply unit on the developing unit viewed in the rotation direction of the developing unit. an image forming apparatus comprising disposed such that the following become the distance to the contact position between the image carrier, rotation of the pre-Symbol developing means on the developing unit in the starting rotation of at least the developing means An unattached area forming means for forming an unattached area where the developer does not adhere is provided in a region from the contact position with the developer supply means to the contact position with the image carrier as viewed in the direction. As an image forming apparatus.
According to the present invention, in order to prevent the waste of the liquid developer as in the prior art, it is necessary to stop the driving of the developing unit in contact with the image carrier, and the developing unit is separated from the image carrier. Since it is not necessary, it is possible to prevent the development performance from being deteriorated due to the damage of the image carrier or the displacement of the developing means. For example, after the image forming operation in the image forming apparatus is finished, the non-attached region forming unit forms the non-attached region on the developing unit, so that the image carrier at the start of the next image forming operation. Unnecessary supply of the liquid developer to the liquid developer is prevented, and waste of the liquid developer can be prevented.

Specifically, as a method of forming the non-adhered region between a position of contact with the image carrier in the developing unit and a position of contact with the developer supply unit, the image carrier, the developing unit, A cleaning means for removing the liquid developer adhering to the developing means on the downstream side in the running direction of the developing means from the contact position, and the supply of the liquid developer to the developing means by the developer supplying means is blocked. A supply blocking means, and at least the liquid developer adhered between the position of contact with the image carrier in the developing means and the position of contact with the developer supply means is removed by the cleaning means, It is conceivable that the supply blocking means prevents the supply of the liquid developer to the area where the liquid developer has been removed by the cleaning means.
Here, it can be considered as an example that the supply blocking means stops the driving of the developer supply means. In this case, since it is not necessary to stop the driving of the developing means, it is possible to prevent damage to the image carrier that is driven in contact with the developing means.
When the developer supplying means includes one or more roller members, the supply of the liquid developer to the developing means is prevented by stopping the driving of any one or more of the roller members. can do.

The supply blocking unit may move the developer supply unit to a position where the liquid developer is not supplied to the developing unit. In this case, since it is not necessary to move the developing means, the positional relationship between the image carrier and the developing means can be maintained normally, and a reduction in developing performance can be prevented.
When the developer supply means includes one or a plurality of roller members, the supply of the liquid developer to the development means is prevented by moving any one or more of the roller members. Can do.

  According to the present invention, in order to prevent the waste of the liquid developer as in the prior art, it is necessary to stop the driving of the developing unit in contact with the image carrier, and the developing unit is separated from the image carrier. Since it is not necessary, it is possible to prevent the development performance from being deteriorated due to the damage of the image carrier or the displacement of the developing means. For example, after the image forming operation in the image forming apparatus is finished, the non-attached region forming unit forms the non-attached region on the developing unit, so that the image carrier at the start of the next image forming operation. Unnecessary supply of the liquid developer to the liquid developer is prevented, and waste of the liquid developer can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a schematic configuration diagram of a color printer X according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an image forming unit 60 provided in the color printer X.
First, a schematic configuration of the color printer X according to the embodiment of the present invention will be described with reference to FIG.
The color printer X forms an image on a sheet using a liquid developer containing a toner made of charged particles having a positive charge and a carrier liquid made of a nonpolar insulating liquid such as isopar or silicon oil. This is a so-called wet image forming apparatus. The color printer X described below is merely an example of an image forming apparatus according to the present invention, and the present invention can also be applied to an image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine. .
As shown in FIG. 1, the color printer X includes a paper feed cassette 10 in which paper is stored, an image forming unit 20 that forms a color image or a monochrome image on the paper supplied from the paper feed cassette 10, The fixing device 30 for fixing the image formed on the paper by the image forming unit 20, the paper discharge tray 40 for discharging the paper on which the image is fixed by the fixing device 30, and the color printer X are controlled in an integrated manner. And a control unit 50.

The image forming unit 20 includes four image forming units 60 provided for black (BK), magenta (M), cyan (C), and yellow (Y), and each of the image forming units 60 described later. An LSU unit 90 that forms an electrostatic latent image on the photosensitive drum 61 by exposing the photosensitive drum 61 to laser light, an intermediate transfer device 70 disposed above the image forming unit 60, and And a transfer roller 80.
The intermediate transfer device 70 includes a driving roller 71 that is rotated by a motor (not shown), a driven roller 72 that rotates as the driving roller 71 rotates, and an endless shape that is stretched over the two rollers. The intermediate transfer belt 73, a tension roller 74 for stretching the intermediate transfer belt 73 while maintaining an appropriate tension, and a toner image formed on the photosensitive drum 61 described later is transferred to the intermediate transfer belt 73. An intermediate transfer roller 75 and a transfer belt cleaning device 76 for removing the liquid developer adhering to the intermediate transfer belt 73 are schematically configured. Note that the number of the image forming units 60 including the intermediate transfer roller 75 and the photosensitive drum 61, which will be described later, is provided by the number of colors.
The transfer roller 80 is disposed to face the driving roller 71 and transfers a toner image formed on the intermediate transfer belt 73 onto a sheet.

The color printer X according to the embodiment of the present invention is characterized by an arrangement relationship between a charging device 63 (described later) and the developing roller 107 (see FIG. 2) in the image forming unit 60. Hereinafter, the image forming unit 60 will be described in detail with reference to FIG.
As shown in FIG. 2, the image forming unit 60 includes a photoconductive drum 61 made of amorphous silicon, a photoconductive drum cleaning device 62 for removing the liquid developer attached to the photoconductive drum 61, and the photoconductive drum. A charging device 63 for charging 61 to a predetermined uniform potential; a charge removing device 64 for removing the potential from the surface of the photosensitive drum 61; and the LSU unit 90 on the photosensitive drum 61 charged to a predetermined potential. And a developing device 65 for developing the electrostatic latent image formed by exposing the laser beam as a toner image using a liquid developer. The charging potential of the photosensitive drum 61 is set to about +200 V to +600 V, for example, but is preferably about +300 V to +400 V based on past experience.

The developing device 65 includes a developer reservoir 101 for storing a liquid developer, an agitation roller 102 for agitating the liquid developer in the developer reservoir 101, and a liquid developer in the developer reservoir 101. A density detection sensor 103 for detecting the toner density of the toner, a liquid level detection sensor 104 for detecting the liquid level of the liquid developer in the developer reservoir 101, and a liquid development in the developer reservoir 101. A pumping roller 105 for supplying the developer to the photosensitive drum 61, a supply roller 106 and a developing roller 107, a cleaning blade 108 for removing the liquid developer adhering to the supply roller 106, the photosensitive drum 61 and the The liquid developer adhering to the developing roller 107 is removed on the downstream side in the rotation (running) direction of the developing roller 107 from the contact position with the developing roller 107. That a cleaning blade 109 (an example of a cleaning unit), and is configured with a.
In the developing device 65, in order to maintain the liquid developer in the developer reservoir 101 at a predetermined amount and a predetermined concentration, the developing device 65 is not suitable depending on the detection results of the concentration detection sensor 103 and the liquid level detection sensor 104. The developer storage unit 101 is supplied with liquid developer from the developer supply device shown in the figure.

Here, the supply roller 106 and the developing roller 107 are applied with a bias of about +100 V to +500 V by a high voltage power source (not shown), and preferably a bias of about +200 V to +300 V is applied to develop the liquid. The agent is efficiently transported. The developing roller 107 is merely an example of a developing unit, and a developing unit composed of a belt member may be used in place of the developing roller 107.
The supply roller 106 is provided with a stop mechanism (not shown, an example of supply blocking means) for stopping the drive of the supply roller 106, and even when the developing device 65 is in operation, the stop mechanism It is possible to stop driving only the supply roller 106. The stop mechanism includes a driving unit such as a solenoid or a motor, and an engaging member that is driven by the driving unit and engages with the supply roller 106. Then, the drive of the drive means is controlled by the control unit 50, and the engagement member engages with the supply roller 106, whereby the drive of the supply roller 106 is stopped.
A driving motor (not shown) for driving the supply roller 106 is provided separately from a driving motor (not shown) for driving the pumping roller 105, the developing roller 107, etc., and the pumping roller is controlled by the control unit 50. In addition to the presence / absence of driving of 105, the developing roller 107, etc., it may be possible to control the presence / absence of driving of the supply roller 106. Also in this case, it is possible to stop the drive of only the supply roller 106. At this time, the control unit 50 that executes a process of stopping a drive motor (not shown) that drives the supply roller 106 corresponds to a supply blocking unit.

As described above, the image forming unit 60 is characterized by the arrangement relationship between the charging device 63 and the developing roller 107.
Specifically, a straight line connecting the center of the charging device 63 and the center of the photosensitive drum 61 when the developing roller 107 and the photosensitive drum 61 rotate at the same linear velocity (moving speed of the outer peripheral surface). The angle formed by D1 and the straight line D2 connecting the center of the developing roller 107 and the center of the photosensitive drum 61 is α1, and the straight line D2 is a straight line D3 connecting the center of the developing roller 107 and the center of the supply roller 106. When the angle formed is α2, the radius of the photosensitive drum 61 is r1, and the radius of the developing roller 107 is r2, the charging device 63 and the developing roller 107 have a relationship of r1 · α1 ≦ r2 · α2. An arrangement relationship is set. That is, the distance (bold line in the figure) s1 from the charging position by the charging device 63 to the developing position by the developing roller 107 on the outer peripheral surface of the photosensitive drum 61 is the photosensitive drum 61 on the outer peripheral surface of the developing roller 107. The distance from the contact position to the contact position with the supply roller 106 (thick line in the figure) s2 or less.
When there is a difference in the linear velocity between the developing roller 107 and the photosensitive drum 61, the linear velocity of the photosensitive drum 61 is V1, and the linear velocity of the developing roller 107 is V2. , R1 · α1 · V2 ≦ r2 · α2 · V1 may be set so that the arrangement relationship between the charging device 63 and the developing roller 107 is set.

Hereinafter, an image forming operation performed by the image forming unit 60 in the color printer X configured as described above will be described with reference to FIG.
When the developing operation by the developing device 65 is completed, the driving of the supply roller 106 is stopped in the developing device 65. Specifically, the driving of the supply roller 106 is stopped by controlling the driving unit of the stop mechanism by the control unit 50. In addition, as described above, the control unit 50 may be controlled to stop only the drive motor for the supply roller 106 as another embodiment.
Thus, by stopping the driving of the supply roller 106, the supply of the liquid developer from the supply roller 106 to the developing roller 107 is blocked. In the configuration in which the liquid developer is supplied to the developing roller 107 by a plurality of roller members (pumping roller 105, supply roller 106) as in the developing device 65, one or a plurality of driving of the plurality of roller members is driven. Just stop. For example, the driving of the pumping roller 105 may be stopped. Also in this case, the supply of the liquid developer to the developing roller 107 is blocked.

On the other hand, even when the developing operation by the developing device 65 ends, the driving of the developing roller 107 and the photosensitive drum 61 is controlled by the control unit 50 so as to continue without being stopped for a while. As a result, the liquid developer remaining on the photosensitive drum 61 and the developing roller 107 is removed by the photosensitive drum cleaning device 62 and the cleaning blade 109.
At this time, if the supply roller 106 is driven, the liquid developer is supplied from the supply roller 106 to the developing roller 107. As described above, at this time, the supply roller 106 is driven. Has been stopped. Therefore, the liquid developer is not supplied from the supply roller 106 to the developing roller 107. Accordingly, the liquid developer is removed by the cleaning blade 109 on the surface of the developing roller 107, and an unattached region where the liquid developer is not attached is formed.
Thereafter, when the developing roller 107 makes one rotation, the driving of the developing roller 107 and the photosensitive drum 61 is stopped. As a result, the entire surface of the developing roller 107 becomes a non-attached area where no liquid developer is attached. Here, the stop mechanism (or the control unit 50) for stopping the driving of the cleaning blade 109 and the supply roller 106 is an example of a non-attached region forming unit.

At the start of the next image forming operation in the color printer X, driving of the photosensitive drum 61, the developing roller 107, and the supply roller 106 is started simultaneously. At this time, in the conventional apparatus, the contact position with the developing roller 107 on the photosensitive drum 61 is not charged to a predetermined potential, but the liquid is transferred to the photosensitive drum 61 by the contact with the developing roller 107. The problem was that the developer adhered.
However, in the developing device 65 according to the present embodiment, at least when the developing roller 107 starts to be driven, at least from the contact position of the developing roller 107 with the photosensitive drum 61 to the contact position with the supply roller 106. Since no liquid developer adheres between them, the liquid developer is not supplied to the photosensitive drum 61 in the meantime. Accordingly, since it is possible to prevent the liquid developer from being supplied to the photosensitive drum 61 while it is not necessary to supply the liquid developer to the photosensitive drum 61, it is possible to prevent waste of the liquid developer. it can. In addition, since it is not necessary to stop the driving of the developing roller 107 driven while being in contact with the photosensitive drum 61 as in the prior art, the photosensitive drum 61 and the developing roller 107 are not in sliding contact with each other. Damage to the photosensitive drum 61 is prevented.
In order to achieve the above-described effects, the image forming apparatus is at least connected to the developer supply unit viewed in the rotation direction of the developing unit on the developing unit at the start of rotation of the developing unit. it is a condition in the area from the contact position to the contact position between the image bearing member is made provided with a non-attachment region forming means for forming a non-adhesive region where the developer does not adhere.

  Further, when the driving of the developing roller 107 is started, the driving of the supply roller 106 is stopped to prevent the supply of the liquid developer to the developing roller 107, and the liquid developer to the photosensitive drum 61 is stopped. It is also possible to control the controller 50 so that the supply roller 106 starts to be driven in accordance with the timing at which the supply is required, and the supply of the liquid developer to the developing roller 107 is started. Thereby, the supply timing of the liquid developer to the photoconductive drum 61 can be arbitrarily adjusted, the supply of unnecessary liquid developer to the photoconductive drum 61 is prevented, and the liquid developer is wasted. It can prevent more reliably.

  When the photosensitive drum 61 is charged to a predetermined potential, writing of the electrostatic latent image by the LSU 90 is started, and the electrostatic latent image is developed by the developing device 65. Note that the writing of the electrostatic latent image by the LSU unit 90 is started at the timing when the electrostatic latent image reaches the developing roller 107 and comes into contact with the attached region where the liquid developer is attached. .

In the present embodiment, after the developing operation by the developing device 65 is completed, the developing roller 107 is driven until it rotates once, and there is an unattached area where the liquid developer is not attached to the entire area of the developing roller 107. The example formed is not limited to this. For example, the liquid developer only between the contact position of the developing roller 107 with the photosensitive drum 61 and the contact position with the supply roller 106 (s2). A non-attached region where no adheres may be formed.
Also in this case, since the distance s1 is less than or equal to the distance s2, at least the liquid developer in the photosensitive drum 61 from the developing position by the developing roller 107 to the charging position by the charging device 63 (s1). Therefore, the waste of the liquid developer can be prevented.

In the first embodiment, another method for preventing the liquid developer from being supplied to the developing roller 107 will be described.
In the embodiment, the driving of the pumping roller 105 and the supply roller 106 is stopped to prevent the liquid developer stored in the developer storage unit 101 from being supplied to the development roller 107, thereby causing the photosensitive roller to move. The method for preventing the liquid developer from being supplied to the body drum 61 has been described.
On the other hand, in order to prevent the liquid developer stored in the developer storage unit 101 from being supplied to the photosensitive drum 61, it is conceivable to block the supply path of the liquid developer. Here, if the developing roller 107 is separated from the photosensitive drum 61 as in the prior art, the liquid developer supply path to the photosensitive drum 61 can be blocked. The positional relationship between the developing roller 107 and the photosensitive drum 61 is likely to be shifted, and there is a possibility that the developing performance is deteriorated.

Therefore, a configuration is proposed in which the supply roller 106 is provided with a roller moving mechanism (not shown) that separates the supply roller 106 from the development roller 107 to the extent that liquid developer is not supplied from the supply roller 106 to the development roller 107. In such a configuration, it is not necessary to move the developing roller 107, and the positional relationship between the developing roller 107 and the photosensitive drum 61 does not shift, so that it is possible to prevent the development performance from being deteriorated. Of course, by separating the supply roller 106 from the developing roller 107 by the roller moving mechanism, the liquid developer is not supplied from the supply roller 106 to the developing roller 107, and the liquid developer to the photosensitive drum 61 is not supplied. The supply path is cut off.
In the configuration in which the liquid developer is supplied to the developing roller 107 by a plurality of roller members (pumping roller 105, supply roller 106) as in the developing device 65, any one or a plurality of the plurality of roller members is used. Move it. For example, the pumping roller 105 may be moved. Also in this case, the supply of the liquid developer to the developing roller 107 is blocked.

In the second embodiment, a configuration using a developing belt mechanism 107a instead of the developing roller 107 will be described. FIG. 3 is a schematic configuration diagram of the image forming unit 60a provided in the color printer X according to the second embodiment of the present invention. Note that the same components as those of the image forming unit 60 are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 3, the developing device 65a of the image forming unit 60a includes a developing belt mechanism 107a instead of the developing roller 107 in the developing device 65 of the image forming unit 60. The developing belt mechanism 107a is stretched over the three rollers, a driving roller 201 that is rotated by a motor (not shown), driven rollers 202 and 203 that rotate as the driving roller 201 rotates. And an endless developing belt 204. The liquid developer remaining on the developing belt 204 is removed by the cleaning blade 110 that contacts the developing belt 204.

Also in the image forming unit 60a configured as described above, by disposing the charging device 63 and the developing belt mechanism 107a as follows, the waste of the liquid developer can be prevented similarly to the image forming unit 60. It is possible.
Specifically, in the image forming unit 60a, when the traveling speed of the developing belt 204 and the linear speed (moving speed of the outer peripheral surface) of the photosensitive drum 61 are the same, the charging device 63 and the photosensitive body. An angle formed by a straight line D4 connecting the center of the drum 61 and the straight line D5 connecting the center of the driving roller 201 and the center of the photosensitive drum 61 is α3, from the straight line D5, the center of the driving roller 201, and the driving roller 201. The angle formed by the straight line D6 connecting the winding start portion M1 of the developing belt 204 to the driving roller 201 is α4, the straight line D7 connecting the driven roller 202 and the supply roller 106, the center of the driven roller 2020, and the driven. An angle formed by a straight line D8 connecting a winding end portion M2 of the developing belt 204 from the roller 202 to the driven roller 202 is α5. The radius of the photosensitive drum 61 is r3, the radius of the driving roller 201 is r4, the radius of the driven roller 202 is r5, and the distance from the winding start portion M1 to the winding end portion M2 of the developing belt 204 is L. Then, the arrangement relationship between the charging device 63 and the developing belt mechanism 107a is set so that the relationship r3 · α3 ≦ (r4 · α4 + r5 · α5 + (180 / π) · L) is established. That is, the distance (bold line in the figure) s3 from the charging position by the charging device 63 to the developing position by the developing roller 107 on the outer peripheral surface of the photosensitive drum 61 is the contact of the developing belt 204 with the photosensitive drum 61. The distance from the position to the contact position with the supply roller 106 (thick line in the figure) s4 or less.
When there is a difference between the running speed of the developing belt 204 and the linear speed (moving speed of the outer peripheral surface) of the photosensitive drum 61, the linear speed of the photosensitive drum 61 is set to V3, the developing speed. When the running speed of the belt 204 is V4, the charging device 63 and the developing roller 107 are set such that the relationship r3 · α3 · V4 ≦ (r4 · α4 + r5 · α5 + (180 / π) · L) · V3 holds. What is necessary is just to set arrangement | positioning relationship.

1 is a schematic configuration diagram of a color printer according to an embodiment of the present invention. 1 is a schematic configuration diagram of an image forming unit provided in a color printer according to an embodiment of the present invention. FIG. 6 is a schematic configuration diagram of a developing unit provided in a color printer according to Embodiment 2 of the present invention.

Explanation of symbols

60: Image forming unit 61: Photosensitive drum (an example of an image carrier)
62 ... Photosensitive drum cleaning device 63 ... Charging device 64 ... Static elimination device 65 ... Developing device 101 ... Developer storage 102 ... Stirring roller 103 ... Concentration detection sensor 104 ... Liquid level detection sensor 105 ... Pumping roller (developer supply) Example of means)
106: Supply roller (an example of developer supply means)
107: Developing roller (an example of developing means)
108 ... Cleaning blade 109 ... Cleaning blade (an example of cleaning means)

Claims (6)

A charging unit that charges the image carrier to a predetermined potential; a developing unit that contacts the image carrier charged to a predetermined potential by the charging unit and supplies a liquid developer to the image carrier; and the development An image forming apparatus comprising: a developer supplying means for supplying the liquid developer to the means;
When the charging unit and the developing unit are viewed in the rotational direction of the image carrier, the distance from the charging position by the charging unit to the developing position by the developing unit on the image carrier is viewed in the rotational direction of the developing unit. An image forming apparatus arranged to be equal to or less than the distance from the contact position with the developer supply means to the contact position with the image carrier in the developing means,
Developer in the region up to the contact position between the image carrier from the contact position between the developing agent supply means viewed in the direction of rotation of the front Symbol developing means on the developing unit in the rotation starting at least said developing means An image forming apparatus comprising: an unattached area forming unit that forms an unattached area that does not adhere. The non-attached region forming means
A cleaning means for removing the liquid developer adhering to the developing means on the downstream side in the running direction of the developing means from the contact position between the image carrier and the developing means;
A supply blocking means for blocking supply of the liquid developer to the developing means by the developer supplying means,
At least the liquid developer adhered between the position of contact with the image carrier and the position of contact with the developer supply means in the developing means is removed by the cleaning means, and the liquid developer is removed by the cleaning means. 2. The image forming apparatus according to claim 1, wherein supply of the liquid developer to the closed area is blocked by the supply blocking unit.   The image forming apparatus according to claim 2, wherein the supply blocking unit stops driving of the developer supply unit. The developer supply means comprises one or more roller members;
The image forming apparatus according to claim 3, wherein the supply blocking unit stops driving one or a plurality of the roller members.   The image forming apparatus according to claim 2, wherein the supply blocking unit moves the developer supply unit to a position where the liquid developer is not supplied to the developing unit. The developer supply means comprises one or more roller members;
The image forming apparatus according to claim 5, wherein the supply blocking unit moves one or more of the roller members.

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