JP4580708B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a wet electrophotographic apparatus applied to a copying machine, a facsimile, a printer, and the like.

    2. Description of the Related Art Conventionally, as this type of cleaning device, there is known a device that removes residual developer on a photoconductor as an image carrier using a removing member that contacts the photoconductor. FIG. 17 is a perspective view showing a schematic configuration of a typical example. In the cleaning apparatus shown in FIG. 17, the residual developer on the photoreceptor 1 is blocked by a cleaning blade 2 as a removing member, and becomes a liquid pool 6 on the photoreceptor 1 near the tip of the cleaning blade 2. The developer in the liquid reservoir 6 tends to move downstream in the rotation direction of the photosensitive member 1 as the photosensitive member 1 rotates. However, since the developer is blocked by the cleaning blade 2, the developer moves onto the cleaning blade 2 in order to move over the cleaning blade 2 and move downstream. With this operation, the developer on the photoreceptor 1 is removed.

  By the way, since the developer in the liquid reservoir 6 is blocked by the cleaning blade 2, it moves also in the ridge line direction of the cleaning blade 2. When the developer moves in the direction of the ridgeline of the cleaning blade 2 and reaches the end before moving onto the cleaning blade 2, the developer flows out from the end of the cleaning blade 2 and is called a liquid ring 9. A phenomenon occurs in which an annular developer adheres to 1. The liquid ring 9 has an annular shape during one rotation of the photosensitive member 1, but moves to the lower end of the photosensitive member 1 when the photosensitive member 1 is stopped, resulting in liquid dripping. Further, the wedge-shaped narrow space 7 formed by the back surface of the cleaning blade 2 and the photoreceptor 1 acts as a capillary tube for the developer in the liquid ring 9, and the developer may wrap around the space 7. These cause fogging, dirt in the machine, and color mixing in a multicolor machine.

The occurrence of the liquid ring 9 is remarkable when the thick surface a of the cleaning blade 2 is directed upward. For example, this is a case where the cleaning blade 2 abuts in the counter direction in the second and third quadrants of the photosensitive member 1 rotating counterclockwise or in the vicinity thereof. This is because the developer easily moves in the ridge line direction of the cleaning blade 2 before moving over the thickness of the cleaning blade 2 and moving downstream. In order to suppress the generation of the liquid ring 9, if the contact position between the cleaning blade 2 and the photosensitive member 1 is defined, the improvement can be added. However, there is a demerit that design freedom is reduced.
Further, even when the cleaning blade 2 is faced downward, when the rotational speed of the photosensitive member 1 is high, or when the viscosity of the developer is high, the developer is difficult to move onto the cleaning blade 2 and the liquid ring 9 is generated. It's easy to do. Thus, these problems cannot be solved only by defining the contact position between the cleaning blade 2 and the photosensitive member 1.

  Patent Document 1 proposes a cleaning device in which a residual developing solution flows downward through both end surfaces of a photosensitive drum by contacting the photosensitive drum with the cleaning blade protruding from both ends of the photosensitive drum. In addition, a cleaning device has been proposed in which a recovery path for receiving residual developer flowing downward along both end faces of the photosensitive drum is provided at both lower ends of the photosensitive drum, and the recovery path includes the end face of the photosensitive drum. Yes.

In the cleaning device described in Patent Document 1, since the recovery path is provided at both ends of the photosensitive member, the device becomes large. Furthermore, an apparatus having a recovery path below the photoconductor has a complicated configuration.
To deal with this problem, Patent Document 2 describes a cleaning device that prevents the occurrence of a liquid ring without providing a recovery path on the end face of the photoreceptor. The cleaning device of Patent Document 2 will be described with reference to FIG.
A developer recovery member 3 having a plurality of protrusions 4 is provided in the vicinity of the contact portion between the cleaning blade 2 and the surface of the photoconductor 1 on the upstream side of the rotation direction of the photoconductor 1 with respect to the cleaning blade 2, and traps the liquid developer by the protrusions. ing. By forming a meniscus in which the liquid developer in a portion in contact with the protrusion is convex, it is possible to block the developer from moving in the ridgeline direction and prevent the occurrence of a liquid ring. Further, unlike the cleaning device described in Patent Document 1, the device does not increase in size or complexity.

Japanese Patent Application Laid-Open No. 08-030157 JP-A-12-352915

  However, in the cleaning device described in Patent Document 2, when the amount of the liquid developer adhering to the surface of the photoreceptor increases, such as when performing high-speed printing, the above-described meniscus formation cannot be made in time, and the liquid developer If the amount of the agent is large, the meniscus will not be able to suppress it. If the meniscus cannot be suppressed, the liquid developer flows to both ends along the cleaning blade, and a liquid ring is generated at a position in contact with the blade end on the surface of the photoreceptor. As a result, fogging, dirt in the machine, and color mixing in a multicolor machine occur.

The present invention has been made in view of the above problems, and its object is to suppress the occurrence of a liquid ring by a cleaning blade , to prevent fogging, in-machine contamination, color mixing in a multicolor machine, and the like. An image forming apparatus having a cleaning unit capable of forming a high-quality image.

In order to achieve the above object, an invention according to claim 1 transfers an image bearing member carrying a visible image formed by a liquid developer and a visible image formed on the image bearing member to a transfer target. An image forming apparatus comprising: a transfer unit; and a cleaning unit that brings a cleaning blade into contact with the surface of the image carrier and collects a residual liquid developer remaining on the surface of the image carrier after the transfer is performed by the transfer unit A foam layer that is in contact with the image carrier at a width that is at least wider than the contact width of the cleaning blade with respect to the image carrier, and is capable of absorbing liquid developer in a surface layer that is in contact with the image carrier the provided, the image bearing member surface movement of the cleaning blade a cylindrical body rotating to move in the opposite orientation to the direction of movement of the surface image bearing member surface at the contact portion between the image bearing member Provided upstream in the direction, It is characterized in that it has a stop member which abuts the foams layer into the foams layer of columnar body to discharge the absorbed liquid developer.
The invention according to claim 2 is the image forming apparatus according to claim 1, wherein the cylindrical body is in contact with the foam layer at a width wider than at least the image area on which the visible image is carried on the surface of the image carrier. The foam layer at the end of the cylindrical body that contacts the outside of the image area on the surface of the image carrier has the foam at the center of the cylindrical body that contacts the image area on the surface of the image carrier. The amount of liquid developer held per unit length in the width direction when passing through the contact portion with the diaphragm member is smaller than that of the body layer.
According to a third aspect of the present invention, in the image forming apparatus of the second aspect, the foam layer has a lower porosity toward the end in the width direction of the cylindrical body.
According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the foam layer at least at both ends in the width direction of the cylindrical body has a single-bubble structure in which bubbles are not continuous. Is.
The invention according to claim 5 is the image forming apparatus according to claim 2, 3 or 4, wherein the foam layer in contact with at least the image area of the cylindrical body has a continuous bubble structure in which bubbles are continuous. It is a feature.
According to a sixth aspect of the present invention, in the image forming apparatus according to the second, third, fourth, or fifth aspect, the thickness of the foam layer at both end portions in the width direction of the cylindrical body is set to be in contact with the image area. It is characterized by being formed thinner than the thickness of the body layer.
The invention according to claim 7 is the image forming apparatus according to claim 2, 3, 4, 5 or 6, wherein the contact pressure of the diaphragm member contacting the columnar body is closer to the end in the width direction of the columnar body. It is characterized by being set high.
According to an eighth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, sixth, or seventh aspect, the aperture member is formed of a surface moving body that moves endlessly, In the contact portion, the surface moves in the opposite direction to the cylindrical body.
According to a ninth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh or eighth aspect, the cylindrical body rotates while discharging the liquid developer by the diaphragm member. The rotational speed of the cylindrical body is set so that the amount of liquid that can be newly absorbed by the foam layer exceeds the liquid amount of the liquid developer at the contact portion between the image carrier and the cylindrical body. It is a feature.
According to a tenth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh, eighth, or ninth aspect, the cylindrical body is separated from the image carrier when not cleaned. It is characterized by this.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, or tenth aspect, the diaphragm member is separated from the cylindrical body during non-cleaning. It is characterized by doing.
According to a twelfth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, or eleventh aspects, the cleaning blade moves the image after completion of the image formation. The image carrier and the cylindrical body are driven while being separated from the surface of the carrier and the cylindrical body is in contact with the surface of the image carrier.

The image forming apparatus of the claims 1 to 12, since the cylindrical body of the image bearing member surface movement direction upstream of the cleaning blade is in contact, to limit the amount of liquid developer that reaches the cleaning blade, the liquid Generation of a ring can be suppressed. Further, since the cylindrical body is in contact with the image bearing member at a width wider than the contact width of the cleaning blade, the liquid developer can be a liquid ring in a position in contact with the cleaning blade edge portion of the image bearing member surface streaks Even if this occurs, the liquid ring can be prevented from growing because it is blocked at the contact position between the image carrier and the cylindrical body. Furthermore, the surface layer that contacts the cylindrical image carrier is a foam layer that can absorb the liquid developer, and also includes a diaphragm member that discharges the liquid developer absorbed by the foam layer. The liquid developer blocked with the cylinder can be recovered.

  According to the first to twelfth aspects of the present invention, the generation of the liquid ring is suppressed and the liquid ring is prevented from growing even if the liquid ring is generated. In addition, there is an excellent effect of preventing color mixing in a multi-color machine and forming a high-quality image stably.

Hereinafter, the present invention will be described using a first embodiment applied to a color copying machine as an image forming apparatus using a liquid developer. The color copying machine according to this embodiment is a tandem type color copying machine. First, the overall configuration and operation of the color copying machine will be described.
FIG. 1 is a schematic configuration diagram of the color copying machine. This color copying machine is provided with an endless belt transfer conveyance belt 10 which can be rotated clockwise in the drawing. Below the transfer conveyance belt 10, four image forming portions 18Y, M, C, and B of yellow, cyan, magenta, and black are arranged side by side along the conveyance direction. Each of the image forming units 18Y, 18M, 18C, and 18B includes drum-shaped photoreceptors 1Y, 1M, 1C, and 1B as latent image carriers. Around the photoreceptors 1Y, 1M, 1C, and 1B, there are a charging device, a developing device, an intermediate transfer drum 501Y, M, C, and B as primary transfer means, a photoreceptor cleaning device, a charge eliminating device, and the like. . In addition, intermediate transfer body cleaning devices 517Y, M, C, and B for removing residual toner remaining on the intermediate transfer drums 501Y, M, C, and B after image transfer are provided. These will be described in detail later. An exposure device 21 is provided below the image forming units 18Y, 18M, 18C, and 18B. In addition, secondary transfer rollers 22Y, 22M, 22C, and 22C as secondary transfer units are provided inside the transfer conveyance belt 10 corresponding to the intermediate transfer drums 501Y, M, C, and B of the image forming units 18Y, 18M, 18C, and 18B. , B. Further, a fixing device (not shown) for fixing the transfer image on the transfer paper is provided downstream of the secondary transfer position in the transfer paper transport direction.

  When copying using the color copying machine having the above-described configuration, when a start switch (not shown) is pressed, the transfer conveyance belt 10 is rotated and conveyed by a drive device (not shown). At this time, the transfer paper P is fed out from a paper feed cassette (not shown), and abutted against a registration roller (not shown) in front of the transfer conveyance belt 10 and stopped. At the same time, the photoreceptors 1Y, M, C, and B are rotated by the individual image forming units 18Y, 18M, 18C, and 18B, and black, yellow, magenta, and cyan are respectively rotated on the photoreceptors 1Y, 1M, 1C, and 1B. A monochromatic image is formed. Each toner image is primarily transferred onto each intermediate transfer drum 501Y, M, C, B. The registration roller is rotated in synchronization with the formation of these single color images, and the transfer paper is fed between the transfer conveyance belt 10 and the intermediate transfer drum 501Y. Then, the secondary transfer rollers 22Y, M, C, and B sequentially transfer the images on the intermediate transfer drums 501Y, M, C, and B to form a composite color image on the transfer paper. The transfer paper P after the image transfer is sent to a fixing device (not shown), and after the transferred image is fixed, the transfer paper P is discharged out of the apparatus. On the other hand, the intermediate transfer drums 501Y, M, C, and B after image transfer are prepared for re-image formation by removing residual toner remaining on the surface by the intermediate transfer body cleaning devices 517Y, M, C, and B.

Next, the individual image forming units 18Y, 18M, 18C, and 18B will be described. The image forming units 18Y, 18M, 18C, and 18B are different in the color of the toner to be accommodated, but the other configuration operations are the same.
FIG. 2 is a schematic configuration diagram of the image forming unit 18. The image forming unit 18 includes a charger 12, an exposure device 21 (not shown), a developing device 40, a transfer device 500 including an intermediate transfer drum 501, a static elimination lamp 17, and a cleaning device 16 around the photoreceptor 1. ing.
As the material of the surface layer of the photoreceptor 1, amorphous silicon (a-Si), organic photoreceptor (OPC), or the like can be used. In addition to the corona discharger as shown in FIG. 2, the charger 12 may be of a type in which a charging roller to which a charging bias is applied is brought into contact with the photosensitive member 1. The exposure device 21 may be an array of LEDs, a laser having a scanning optical system, or a light image from a document illuminated by a printer.

A case where an image is formed by reversal development in the image forming unit 18 will be described. The photosensitive member 1 is rotationally driven in the arrow direction at a constant speed during copying by a driving means such as a motor (not shown). Then, after being uniformly charged in the dark by the charger 12, a light image corresponding to the image is irradiated by the exposure device 21, and the electrostatic latent image is carried on the outer peripheral surface of the photoreceptor 1. Thereafter, the electrostatic latent image is developed with the charged toner attached while passing through the developing device 40. Then, the toner image is primarily transferred onto the intermediate transfer drum 501. The image on the intermediate transfer drum 501 is transferred to the transfer paper P that is transported to the transfer transport belt 10. Thereafter, the charge remaining on the surface of the photoreceptor 1 is neutralized by the charge eliminating lamp 17. Then, the toner remaining on the surface of the photoreceptor 1 is removed by the photoreceptor cleaning device 16.
The transfer device 500 is not limited to the transfer method using the electrostatic roller of the paper, but a method using corona discharge, an adhesive transfer method, a thermal transfer method, or the like may be used.

  The developing device 40 of the present embodiment is a developing device that uses a liquid developer. This liquid developer is a low-viscosity and low-concentration liquid developer that has been generally commercially available and used, for example, in an insulating liquid carrier called Isopar (trade name: manufactured by ExxonMobil Corp.). It is not a low-viscosity liquid developer of about 1 cSt containing toner of a high concentration but a high-viscosity high-concentration liquid developer. The highly viscous and high concentration liquid developer uses a carrier having high insulation properties such as silicone oil, normal paraffin, IsoparM (trade name: manufactured by ExxonMobil), vegetable oil, mineral oil, and the like as a solvent. The solvent contains a toner having a concentration of about 5 to 40 wt%, and is a liquid developer having a viscosity of about 50 to 10,000 mPa · S. As the liquid developer, a volatile or non-volatile developer can be selected and used according to the purpose. Further, the particle diameter of the toner is similarly adjusted from submicron to about 6 μm.

Next, the developing device 40 of the copying machine according to the present embodiment will be described.
As shown in FIG. 2, the developing device 40 includes a developing roller 42 that is rotatably disposed within a developer storage tank 41 that stores a liquid developer D therein, and a rotatably disposed within a casing 50. The sweep roller 45 is provided. Further, the developing device 40 includes a coating device 43 for applying the liquid developer D to a developing roller 42 as a member to be coated. The coating device 43 includes a coating roller 46 whose surface as a coating member is engraved with a uniform pattern, an intermediate roller 47 as an intermediate coating member for coating the developing roller 42 with the liquid developer D, and a liquid developer D. It is mainly composed of an agitating / conveying screw 48 as an agitating / conveying means.
Further, the developing roller 42 and the sweep roller 45 are provided with cleaning members 49 and 45b made of a metal blade or a rubber blade, respectively. The cleaning members 49 and 45b may be roller type instead of blade type.

  In the coating device 43, the intermediate roller 47 contacts the surface of the coating roller 46 to remove excess liquid developer D on the surface, thereby regulating the amount of developer carried on the surface of the coating roller 46. Also serves as a doctor roller. Then, the liquid developer applied to the application roller 46 and measured by a doctor blade 46b as an application amount regulating member is transferred onto the surface of the intermediate roller 47.

  Further, as shown in FIG. 3, the intermediate roller 47 is provided with an intermediate roller elastic layer 42b made of an elastic body on the outer peripheral surface of the intermediate roller core 42a serving as a core metal, and further slides on the outer peripheral surface of the intermediate roller elastic layer 42b. The structure is provided with a conductive layer 42c. As a material of the intermediate roller elastic layer 47b of the intermediate roller 42, urethane rubber can be used. The material of the intermediate roller elastic layer 47b is not limited to urethane rubber, and may be any material that does not swell or dissolve with the carrier liquid / developer.

Next, cleaning of the photosensitive member will be described.
FIG. 4 shows a configuration in which the cleaning blade 2 is brought into contact with the conventional photoreceptor 1 to remove the developer. The cleaning blade 2 is in contact with the surface of the photosensitive member 1 with a width wider than the width of the liquid developer adhesion region α which is an image region on the photosensitive member 1.
When cleaning is performed in this state, the liquid developer passes over the cleaning blade 2 and flows in the direction of the arrow β along the contact portion of the cleaning blade 2 and is collected at the end of the cleaning blade 2 Some move towards
As shown in the drawing, the liquid developer reaching the end of the cleaning blade 2 forms a liquid ring R, and the liquid developer remains on the surface of the photoreceptor 1. This becomes prominent when gravity is difficult to pass through the flow of the liquid developer removed by the cleaning blade.

Next, the cleaning device 16 of this embodiment will be described. FIG. 5 is an explanatory diagram of the cleaning device 16.
The cleaning device 16, the click leaning blade 2 to the photosensitive member 1 rotating direction upstream side, in contact with the photosensitive member 1 in a wide contact width than the cleaning blade 2, the elastic layer surface layer is made of a granulated foam porous structure A cleaning roller 161, which is 161a, is provided. A diaphragm roller 162 as a diaphragm member is in contact with the cleaning roller 161. As the material of the squeezing rollers 162 may be a resin which does not swell in a liquid used as a carrier, the carrier used in this embodiment is a silicone over N'oiru, it may be a urethane resin.

It is possible to squeeze out the liquid developer held on the elastic layer 161a of the cleaning roller 161 as a squeezing member regardless of whether the squeezing roller 162 is rotatable or fixed. Hereinafter, a configuration in which the squeeze roller 162 is rotatable will be described.
The surface movement direction of the squeezing roller 162 at the contact portion with the cleaning roller 161 is rotated in a direction opposite to that of the cleaning roller 161, and the squeezing roller is disposed downstream of the contact portion in the rotation direction of the squeezing roller 162. A blade 162b is provided.
The liquid developer squeezed out by the cleaning roller 161 is removed from the surface of the squeezing roller 162 by the squeezing roller blade 162b and collected. The squeezing roller 162 is longer in the width direction than the cleaning roller 161, and the squeezing roller blade 162 b in contact with the squeezing roller 162 is longer in the width direction than the squeezing roller 162, so that the liquid developer collected by the cleaning roller 161 is surely cleaned. 16 can be contained.

  FIG. 6 is an explanatory diagram of the cleaning roller. FIG. 6A is an overall view of the cleaning roller 161. Abutting rollers 161c are provided at both ends of the roller body whose surface is the elastic layer 161a. FIG. 6B is a cross-sectional view of the cleaning roller 161. The clean roller 161 is provided with an elastic layer 161a made of a foam around the cored bar 161b. FIGS. 6C and 6D are diagrams showing the relationship between the elastic layer 161a and the butting roller 161c. As shown in FIG. 6C, the radius of the butting roller 161c is smaller by d1 than the radius of the elastic layer 161a. Then, as shown in FIG. 6D, the abutting roller 161c comes into contact with the photoreceptor 1, and the elastic layer 161a is indented by d1 and comes into contact with the photoreceptor 1. Thereby, the contact width of the cleaning roller 161 with respect to the photosensitive member 1 is determined.

FIG. 7A is an explanatory diagram showing a state in which the cleaning roller 161 is in contact with the photosensitive member 1, and FIG. 7B is a diagram illustrating a state where a squeezing roller 162 as a squeezing member is added to the cleaning roller 161 in FIG. It is explanatory drawing of the state which is contact | abutting. As shown in FIG. 7A, the cleaning roller 161 is in contact with the photoconductor 1 with a width wider than the width at which the cleaning blade 2 is in contact with the photoconductor 1. The cleaning roller 161 is driven by a driving device (not shown) so as to change the surface movement direction of the photosensitive member 1. The liquid developer remaining on the surface of the photoreceptor 1 can be removed by contacting the photoreceptor 1 so that the surface moving direction is reversed. Specifically, the cleaning roller 161 abuts in the direction of surface movement opposite to that of the photoreceptor 1, and stops the liquid developer remaining on the surface of the photoreceptor 1 by the abutment portion. The elastic layer 161a, which is a foam, can absorb the liquid developer, and the pores of the foam absorb the damped liquid developer and remove the liquid developer from the surface of the photoreceptor 1.
As shown in FIG. 7B, the squeezing roller 162 longer than the cleaning roller 161 is in contact with the cleaning roller 161. When the squeezing roller 162 comes into contact with the cleaning roller 161, the elastic layer 161a absorbs from the surface of the photoreceptor 1, and the liquid developer held in the hole can be squeezed out. As shown in FIG. 5, the squeezed liquid developer is collected through the same path as the liquid developer collected by the cleaning blade 2.
Since most of the liquid developer remaining on the surface of the photoreceptor 1 is damped and collected by the cleaning roller 161, the liquid developer to be removed can be reduced by the cleaning blade 2, and the liquid ring R is generated at the end of the cleaning blade 2. Can be suppressed. Further, as indicated by a broken line liquid ring contact position 161r in FIG. 7A, the cleaning roller 161 is in contact with a position where the liquid ring R is generated on the surface of the photoreceptor 1. Thus, even if the liquid ring R is generated, the elastic layer 161a absorbs the liquid developer that forms the liquid ring R when the rotation is made approximately one rotation, so that the liquid ring can be prevented from growing.
The elastic layer 161 a can suck in the liquid developer and discharge it, so that the liquid ring R can be sucked in and the liquid developer can be removed by the squeeze roller 162. Therefore, it is necessary to select a material that does not swell in the liquid developer for the foam forming the elastic layer 161a. As the foam used in the elastic layer 161a, a foam formed by foaming urethane resin was used.

In this way, the cleaning roller 161, which is at least a part of a porous foam cylindrical body, contacts and rotates in the direction of surface movement opposite to that of the photoreceptor 1. In the region where the cleaning roller 161 is in contact with the photosensitive member 1, the liquid ring also has an absorbing action and can easily absorb the liquid developer. The liquid developer absorbed by the cleaning roller 161 is squeezed by the squeeze roller 162 to discharge the impregnated liquid developer. Since the surface of the cleaning roller 161 is porous, the liquid developer remains on the surface of the photosensitive member 1 after the cleaning roller 161 comes into contact therewith, but since the amount is small, it is neatly removed by the cleaning blade. . Even if the liquid ring R is generated at this time, the end portion of the cleaning roller 161 absorbs the liquid developer forming the liquid ring R, so that the liquid ring R can be prevented from growing. Thereby, the transfer residual liquid developer on the surface of the photoreceptor 1 can be easily removed. The cleaning roller 161 keeps the amount of liquid developer held by the squeeze roller 162, and the cleaning roller 161 again comes into contact with the surface of the photosensitive member 1 to transfer residual liquid developer and liquid ring in the liquid developer adhesion region α. The liquid developer that forms R is removed.
It is possible to prevent the liquid developer in the liquid ring R from splashing or dripping from the lower side of the photoconductor 1 due to the rotation of the photoconductor 1, and to prevent fogging, in-machine dirt, color mixing in a multicolor machine, and the like. . Therefore, stable image formation can be performed.

The liquid developer remaining on the surface of the photoreceptor 1 is electrically aggregated by the sweep roller 45 and the like, and the solid particles are in a compressed state, so that cleaning with the cleaning blade 2 alone is difficult. Further, the blade tip at the contact position between the cleaning blade 2 and the photosensitive member 1 to be cleaned is easily worn. The wear at the tip of the cleaning blade 2 greatly affects the cleaning performance. As in this embodiment, by providing the cleaning roller 161 on the upstream side in the rotation direction of the photosensitive member 1 from the cleaning blade 2, the burden on the cleaning blade 2 is reduced.
However, since the liquid developer remaining in the liquid developer adhesion region α, which is the image area, is in a state where there are many solid components, it is difficult to remove even if the elastic layer 161a in a state where the liquid components to be held are in contact with each other. It is a state. In particular, when a paper jam occurs, transfer to the recording paper P is not performed, and a lot of liquid developer is cleaned, so that the fixed developer increases and the above-described problem becomes remarkable.
As shown in FIG. 8, the cleaning roller 161 includes a cleaning roller central portion 161m that is in contact with the liquid developer adhesion region α and a cleaning roller end portion that is in contact with the outside of the end portion of the liquid developer adhesion region α. 161s. In the cleaning roller central portion 161m, the liquid developer adhering to the photosensitive member 1 may be fixed. Therefore, the elastic layer 161a has a certain amount of developer in order to solve the fixed solid component with the liquid component. It is desirable to hold it. On the other hand, since the cleaning roller end portion 161s is outside the liquid developer adhesion region α, there is almost no fixed developer, but a liquid ring may be formed, and in order to absorb and remove the photoconductor It is desirable that the liquid developer contained in the elastic layer 161 a in contact with 1 is squeezed out by the squeezing roller 162. As described above, the proper amount of liquid developer held at the time of contact with the photosensitive member 1 differs between the cleaning roller central portion 161m and the cleaning roller end portion 161s.

  In the cleaning device 16 used in the present embodiment, the holding amount of the liquid developer is varied in the width direction of the cleaning roller 161 at the time of cleaning. Specifically, the amount of liquid developer held by the cleaning roller 161 on the end side of the region where the end of the cleaning blade 2 abuts is the liquid developing portion where the liquid developer adhering region α that is the image region abuts. It should be less than the amount of agent retained.

[Example 1]
Hereinafter, a first example (hereinafter referred to as Example 1) in which the amount of liquid developer held in the width direction of the cleaning roller 161 is different will be described.
FIG. 9 is an explanatory diagram of the cleaning roller 161 according to the first embodiment. In Example 1, the climatic rate of the foam of the cleaning roller 161 is higher at the end in the width direction, and the bubble rate at the liquid ring contact position 161r where the liquid ring shown by the broken line contacts is lowest.
FIG. 9A shows a material in which the bubble rate is continuously different so that the bubble rate is higher at the center part by controlling the foaming amount at the time of manufacture so that the bubble rate is different in the width direction with one material. This is the cleaning roller 161 used.
Further, as shown in FIG. 9B, a cleaning roller 161 made of a material having a high bubble rate may be used at the cleaning roller central portion 161m, and a material having a low bubble rate may be used at the cleaning roller end portion 161s.
FIG. 9C is a diagram illustrating a contact state of the squeeze roller 162 in the first embodiment. Since the air bubbles are uniformly contacted in the width direction, the higher the bubble ratio of the cleaning roller 161, the more the foam after passing through the squeeze roller 162 holds the liquid developer.

Thus, by increasing the bubble ratio of the cleaning roller central portion 161m, it is possible to increase the amount of liquid developer retained, and when it comes into contact with the photoreceptor 1, it is fixed in a state containing a liquid component. It will come into contact with the developer. When the fixed developer comes into contact with the foam containing the liquid component, the developer can be unwound and flow, so that the developer is easily removed. As a result, the developer fixed on the surface of the photoreceptor 1 can be easily removed by the cleaning roller 161 or the cleaning blade 2.
Further, by reducing the bubble ratio of the cleaning roller end portion 161s, the foam after passing through the squeeze roller 162 can discharge the liquid developer and can contact the photoreceptor 1 in a fresh state. Since the foam in a fresh state is likely to contain a liquid component, the liquid ring R adheres to the cleaning roller end 161 s and can be removed from the photoreceptor 1.

[Example 2]
Next, a second embodiment (hereinafter referred to as a second embodiment) in which the amount of liquid developer held in the width direction of the cleaning roller 161 is different will be described.
FIG. 10 is an explanatory diagram of the cleaning roller 161 according to the second embodiment. FIG. 10 (a) is an overall view of the cleaning roller 161, and the central portion 161m of the cleaning roller uses a foam having a continuous bubble structure in which bubbles that are generally used are connected. On the other hand, the cleaning roller end portion 161s uses a foam having a single bubble structure in which bubbles are not connected to each other. FIG. 10B is a cross-sectional view of the cleaning roller end portion 161s made of a foam having a single bubble structure. As shown in the figure, the bubbles are not connected to each other, and the liquid developer is conveyed by a cell formed of a sponge of the surface layer. As described above, since the cleaning roller end portion 161s has a single bubble structure, the liquid ring can be trapped by unevenness on the surface of the cleaning roller 161, and the liquid holding force at the end portion is small, so that it is easily held by the squeezing roller. The liquid developer can be removed.
Further, when contact pressure is applied by the squeeze roller and the developer held in the foam is removed, the liquid developer reaches the end of the cleaning roller 161 through the holes when the foam is open-celled, There was a risk that a liquid ring would occur at the end of the cleaning roller 161. However, by using a foam having a single bubble structure for the cleaning roller end portion 161s, the liquid developer does not move through the holes as in the continuous bubble structure, so that the cleaning roller 161 generates a liquid ring. Can be prevented.

  When a foam having a single bubble structure with independent pores is used as in Example 2, the compressed toner particles can be released, but since the amount of liquid that can be sucked is small, absorption after jamming occurs. When the liquid developer to be increased increases, it becomes impossible to cope. Therefore, in the following examples, a foam having a continuous cell structure is used. This makes it possible to cope with an increase in the amount of liquid developer to be absorbed.

[Example 3]
Hereinafter, a third embodiment (hereinafter referred to as a third embodiment) in which the amount of liquid developer held in the width direction of the cleaning roller 161 is different will be described.
FIG. 11 is an explanatory diagram of the cleaning roller 161 used in the third embodiment. FIG. 11A shows a state in which the cleaning roller 161 is in contact with the photosensitive member 1. FIGS. 11B and 11C are cross-sectional views of the cleaning roller 161 in a cross-section A2 that is a cut surface of the cleaning roller end portion 161s in FIG. 11A. FIGS. 11D and 11E are cross-sectional views of the cleaning roller 161 in a cross-section A1 that is a cut surface of the cleaning roller central portion 161m in FIG. 11A. Further, FIG. 11 (f) is a cross-sectional view taken along a cut surface along the axis of the cleaning roller 161.
As shown in FIGS. 11B to 11F, the elastic layer 161a of the cleaning roller end portion 161s of the cleaning roller 161 is set to the elastic layer 161a of the cleaning blade central portion 161m that abuts the liquid developer adhesion region α. It is formed thinner than the layer thickness. As shown in FIGS. 11B and 11D, for the cleaning roller 161 having a uniform outer diameter in the axial direction, the outer diameter of the core metal 161b at the cleaning roller end 161s including the liquid ring contact position 161r is set. The outer diameter of the metal core 161b at the cleaning roller central portion 161m is larger. By increasing the outer diameter of the metal core 161b, the elastic layer 161a at the cleaning roller end portion 161s can be formed thinner than the elastic layer 161a at the cleaning roller central portion 161m.

  As shown in FIG. 11C, the cleaning roller end 161s can squeeze almost all of the liquid developer held in the pores by squeezing the porosity of the elastic layer 161a by the squeezing roller 162. It can abut against the photoreceptor 1 in a fresh state. Also, as shown in FIG. 11E, the cleaning roller central portion 161m has a larger porosity than the amount of the elastic layer 161a crushed by the squeezing roller 162, so that the liquid developer is held in the pores. Can be applied to the photosensitive member 1 while maintaining the above.

  The elastic layer 161a at the cleaning roller end portion 161s is in a fresh state after the squeeze roller 162, so that the liquid developer can be easily sucked and the growth of the generated liquid ring R can be prevented. In addition, the elastic layer 161a of the cleaning roller central portion 161m is in contact with the photosensitive member 1 in a state containing the liquid developer even after the stop of the squeezing roller. In other words, the liquid developer adhesion region α is in a state where the wet porous body is in this state. As a result, the toner particles, which are solid components on the surface of the photosensitive member 1 subjected to the compression, are broken into liquid components and can be cleaned well.

Thus, by forming the cored bar 161b into a tapered shape, the elastic layer 161a can be bonded after the cored bar 161b is formed. Further, since the liquid developer held in the pores of the cleaning roller 161 moves to the central portion with little compression when coming into contact with the squeezing roller 162, a liquid ring is formed outside the cleaning roller end portion 161s. Can be prevented. The wet state of the cleaning roller 161 can be easily realized by making the metal core 161b into a tapered shape and making the distance between the surface of the squeeze roller 162 and the surface of the cleaning roller 161 constant.
In addition, since the squeezing roller 162 has a columnar shape compared to the shape of the squeezing roller 162, which will be described later, the contact pressure is increased toward the end side, the abutting when the squeezing roller blade 162b is provided on the squeezing roller 162. It becomes easy.
Further, the liquid developer squeezed and collected from the cleaning roller 161 by the squeezing roller 162 is removed by the rotation of the squeezing roller 162. The collected developer adhering to the squeezing roller 162 is removed by the squeezing roller blade 162b, and the squeezing roller 162 contacts the cleaning roller 161 on the cleaned surface. Thereby, stable cleaning can be performed.

  Further, the cored bar 161b having an outer diameter different in the axial direction of the cleaning roller 161 is not limited to the shape shown in FIG. 11 (f), and the core shown in FIGS. 11 (g) and 11 (h). A cleaning roller 161 having gold 161b may be used.

[Example 4]
Hereinafter, a fourth embodiment (hereinafter referred to as a fourth embodiment) in which the amount of liquid developer held in the width direction of the cleaning roller 161 is different will be described.
FIG. 12 is an explanatory diagram of the cleaning device 16 used in the fourth embodiment. FIG. 12A shows a state in which the cleaning roller 161 is in contact with the photosensitive member 1. FIG. 12B is a cross-sectional view taken along a cross-section A that is a cut surface of the cleaning roller 161 in FIG. FIG. 12C shows a state where the squeezing roller 162 is in contact with the cleaning roller 161. FIG. 12D is a cross-sectional view of a contact portion between the cleaning roller 161 and the squeezing roller 162 in a cross section A2 which is a cut surface on the end side of the cleaning roller 161 in FIG. Further, FIG. 12E is a cross-sectional view of a contact portion between the cleaning roller 161 and the squeezing roller 162 in a cross-section A1 that is a cut surface of the central portion of the cleaning roller 161 in FIG.
In Example 4, the cleaning roller 161 is formed of a uniform foam in the width direction, and has a cross-sectional shape as shown in FIG. 12B and a uniform cross section in the width direction.

In the fourth embodiment, the contact pressure of the squeeze roller 162 that contacts the cleaning roller 161 is set higher toward the end in the width direction of the cleaning roller. Specifically, as shown in FIG. 12C, the outer diameter of the squeezing roller 162 that contacts the cleaning roller 161 having the same cross section in the width direction is set so as to increase toward the end of the cleaning roller 161. ing.
As shown in FIG. 12D, since the outer diameter of the squeeze roller 162 is set large in the cross section A2, the elastic layer 161a of the cleaning roller 161 can be appropriately crushed and held in the pores. Almost all of the liquid developer can be squeezed out and can be applied to the photoreceptor 1 in a fresh state. Further, as shown in FIG. 12E, since the outer diameter of the squeeze roller 162 is set to be small in the cross section A2, the porosity is larger than the amount by which the elastic layer 161a is crushed. It is possible to apply to the photosensitive member 1 while maintaining the state where the agent is held.

The elastic layer 161a on the end side of the cleaning roller 161 is in a fresh state after coming into contact with the squeezing roller 162, so that the liquid developer is easily sucked and the liquid developer that forms the liquid ring R is absorbed well. And the growth of the generated liquid ring R can be prevented. Further, the elastic layer 161a at the center of the cleaning roller 161 is in contact with the surface of the photoreceptor 1 in a state containing the liquid developer even after contact with the squeezing roller 162. In other words, the liquid developer adhesion region α is in a state where the wet porous body is in this state. As a result, the toner particles, which are solid components on the surface of the photosensitive member 1 subjected to the compression, are broken into liquid components and can be cleaned well.
Further, the cleaning roller 161 used in Example 4 does not reduce the porosity of the elastic layer 161a on the end side or does not reduce the layer thickness. Can absorb the liquid developer. Further, since the liquid developer held in the pores of the cleaning roller 161 moves to the central portion with little compression when coming into contact with the squeezing roller 162, it is possible to prevent the liquid ring R from being formed by the cleaning roller 161. .
The squeeze roller 162 is not limited to the shape shown in FIG. 12C, and a shape as shown in FIG.

Even when the cleaning roller 161 is not cleaned, the elastic layer 161a of the cleaning roller 161 may be permanently deformed if it remains in contact with the photosensitive member 1 with pressure applied, and may not return to its original state.
Therefore, the cleaning roller 161 according to the present embodiment is separated from the photosensitive member 1 during non-cleaning. Hereinafter, the contact / separation mechanism of the cleaning roller 161 with respect to the photoreceptor 1 will be described. FIG. 13 is an explanatory diagram of a contact / separation mechanism for the photosensitive member 1 of the cleaning device 16 including the cleaning roller 161. The cleaning roller 161 is set so as to be always separated from the photosensitive member 1 by a pressure biasing spring 164 attached to the cleaning device 16, and the photosensitive member 1 is contacted by the contact / separation cam 165 so as to be in contact with the photosensitive member 1 during the image forming operation. The contact pressure is applied to. Specifically, when the contact / separation cam 165 is at the contact position 165a indicated by the solid line, the cleaning roller 161 contacts the photoreceptor 1. On the other hand, when the contact / separation cam 165 is at the separation position 165 b indicated by a broken line, the cleaning roller 161 is separated from the photosensitive member 1.
The cleaning device 16 enables the photosensitive member 1 and the cleaning device 16 to contact and separate with the holding bar 2b of the cleaning blade 2 as the center of rotation. By using the holding bar 2b of the cleaning blade 2 as the center of rotation, both the cleaning roller 161 and the cleaning blade 2 can contact and separate from the photoreceptor 1 independently. Further, the contact / separation method is not limited to the configuration using the contact / separation cam, and a contact pressure can be applied to the photosensitive member 1 by a solenoid or the like.
When the cleaning roller 161 is not cleaned, the elastic layer 161a can be prevented from being permanently deformed by separating the cleaning roller 161 from the photoreceptor 1.

In addition, when the squeezing roller 162 is not in the cleaning state and remains in contact with the cleaning roller 161 in a state where pressure is applied, the elastic layer 161a of the cleaning roller 161 in contact with the squeezing member is permanently deformed and returned to its original state. There is a risk of disappearing.
Therefore, the squeezing roller 162 of the present embodiment is separated from the cleaning roller 161 when not cleaned. Hereinafter, the contact / separation mechanism of the squeeze roller 162 with respect to the cleaning roller 161 will be described. FIG. 14 is an explanatory diagram of a contact / separation mechanism of the squeeze roller 162 with respect to the cleaning roller 161.
The squeezing roller 162 is set so as to be always away from the squeezing member with respect to the cleaning roller 161, and a contact pressure is applied by the solenoid 167 so as to contact the cleaning roller 161 during the image forming operation. Further, the contact / separation mechanism is not limited to a configuration using a solenoid, and the contact pressure of the squeeze roller 162 against the cleaning roller 161 may be applied by a cam or the like.
During non-cleaning, the elastic roller 161a of the cleaning roller 161 can be prevented from being permanently deformed by separating the squeeze roller 162 from the cleaning roller 161.

In a state where the amount of liquid developer that can be impregnated by the porous elastic layer 161a relative to the amount of liquid developer on the surface of the photoreceptor 1 is small, or in a state where the elastic layer 161a is sufficiently filled with the liquid developer. When contacting the photoreceptor 1, there is a risk that a liquid ring is formed at the contact positions of both ends of the cleaning roller 161. The liquid ring is generated when the liquid developer that could not be absorbed overflows from the end of the cleaning roller 161 at the contact positions of both ends of the cleaning roller 161.
Since the elastic layer 161 a of the cleaning roller 161 is configured with a predetermined porosity, the amount of liquid that can be newly held in the elastic layer 161 a every time the cleaning roller 161 rotates is the compression amount when compressed by the squeeze roller 162. Determined by. The amount of liquid that can be newly held is determined by the contact pressure of the squeeze roller 162 against the cleaning roller 161. However, even if the amount of compression is increased in order to increase the amount of liquid that can be held by the elastic layer 161a, there is a limit to the increase in the amount of compression.

In the cleaning device 16, the cleaning roller 161 rotates while discharging the liquid developer by the squeezing roller 162, and the amount of liquid that can be newly absorbed by the elastic layer 161 a is the liquid developer in the nip portion between the cleaning roller 161 and the squeezing roller 162. The rotational speed of the cleaning roller 161 is set so as to exceed the amount of liquid.
In the cleaning device 16, the amount of absorption of the liquid developer per time of the cleaning roller 161 is increased by setting the rotation number of the cleaning roller 161 to be high, and the elastic layer 161 a is more than the amount of liquid developer in the nip portion. Increase the amount of liquid that can be newly absorbed. Since the amount of liquid that can be newly absorbed by the elastic layer 161a is larger than the amount of liquid developer at the nip, the liquid developer does not overflow at both ends of the cleaning roller 161, and at the end of the nip. The occurrence of a liquid ring can be prevented.

In particular, at the cleaning roller end 161s, the liquid ring R is formed at the end of the cleaning blade 2, so that the amount of liquid that can be absorbed by the elastic layer 161a is less than the amount of liquid developer forming the liquid ring R. It is easy to become. And since it is a roller edge part, a liquid ring is easy to be formed in the contact position of the both ends of the cleaning roller 161. FIG.
This is because the amount of liquid that can be newly absorbed by the cleaning roller end 161 s is larger than the amount of liquid developer that forms the liquid ring R generated at the end of the cleaning blade 2. Prevent by setting the rotation speed.

Further, in order to remove the liquid ring R, the cleaning roller end portion 161s preferably contains as little liquid as possible after contact with the squeezing roller 162. Therefore, it is necessary to sufficiently compress with the squeezing roller. In other words, it is essential that the pores formed in the sponge are in a collapsed state or not more than can be contained in the sponge when absorbed by the liquid ring R.
If the liquid volume cannot be absorbed, a liquid ring different from the liquid ring R is formed at the end of the cleaning roller 161. Therefore, the liquid volume of the liquid ring R always exceeds the liquid volume that can be absorbed. Must not.
The contact time is set so that the elastic layer 161a is impregnated with less than 100% of the amount of liquid that can be absorbed in the nip where the cleaning roller 161 and the photosensitive member 1 are in contact. That is, the contact time was set by the number of rotations of the cleaning roller.
Since excessive liquid developer is not absorbed by the cleaning roller 161, it is possible to prevent the occurrence of a liquid ring that tends to occur at the roller end.

When the cleaning operation is completed and the cleaning blade 2 and the cleaning roller 161 are simultaneously separated from the photoconductor 1, the photoconductor is in a state in which the liquid ring R generated at the end of the cleaning blade 2 remains formed. 1 may adhere to the surface or hang from the lower side of the photosensitive member 1 to cause in-machine contamination.
Therefore, in the cleaning device 16 of the present embodiment, after the image forming operation is finished, the cleaning blade is first separated from the surface of the photoreceptor. Then, the photoconductor 1 and the cleaning roller 161 are driven while the cleaning roller 161 is kept in contact with the photoconductor 1. As the number of times of driving, a predetermined number of rotations may be driven, or a sensor is provided in a portion where the liquid ring R on the surface of the photoconductor 1 is generated to confirm that there is no liquid ring R on the photoconductor 1. You may stop after that. In this way, after the cleaning operation is completed, the cleaning blade 2 is separated and the photosensitive member 1 and the cleaning roller 161 are driven, so that the developer that could not be removed by the contact of the cleaning roller 161 once is completely removed. Can be removed. Therefore, a good standby state can be obtained after the image formation is completed.
In this embodiment, a cleaning roller 161 and a squeezing roller 162 that are parallel to the photosensitive member 1 are provided, and the recovery path for the removed liquid developer is the same as the recovery path for the conventional cleaning blade 2. The structure is simple and downsizing is possible.

As described above, according to the present embodiment, than torque leaning blade 2 to remove the liquid developer remaining on the surface of the photosensitive member 1 as an image bearing member, as a cylindrical body in the surface movement direction upstream side of the photosensitive member 1 A cleaning roller 161 is provided. The cleaning roller 161 is in contact with the photosensitive member 1 with a width wider than the contact width of the cleaning blade 2, and at least one part in contact with the photosensitive member 1 is an elastic layer 161 a that is a foam layer capable of absorbing the liquid developer. . Further, the cleaning roller 161 rotates so that the surface movement direction is opposite to that of the photosensitive member 1. Further, a squeezing roller 162 is provided as a squeezing member for discharging the liquid developer absorbed by the elastic layer 161a of the cleaning roller 161. Since the cleaning roller 161 is wider than the cleaning blade 2 and abuts on the upstream side in the movement direction of the surface of the photoconductor 1, the amount of the liquid developer reaching the cleaning blade 2 can be reduced and the generation of the liquid ring R can be suppressed. Can do. Further, since the cleaning roller 161 is also in contact with the position where the liquid ring R is formed on the surface of the photosensitive member, even if the liquid ring R is generated, the cleaning roller 161 can be damped at the contact portion with the photosensitive member 1, It is possible to prevent the ring from growing. This prevents fogging due to the liquid ring R, dirt in the machine, and color mixing in a multicolor machine, and enables stable and high-quality image formation.
Further, the cleaning roller 161 abuts on the elastic layer 161a with a width wider than the liquid developer application area α, which is an image area on the surface of the photoreceptor 1, and varies the amount of liquid developer retained in the elastic layer in the width direction. ing. Specifically, the amount of liquid developer held by the elastic layer 161a is set to be smaller on the end side of the cleaning roller 161 than on the portion where the elastic developer 161a contacts the liquid developer application region α. By increasing the amount of liquid developer retained in the elastic layer 161a that is in contact with the liquid development region α, the cleaning roller 161 is in contact with the photoreceptor 1 in a wet state. Even when there is a solid component of the liquid developer compressed and fixed on the surface of the photosensitive member 1 by the wet cleaning roller 161 coming into contact with the liquid developer adhesion region α, the liquid component held by the cleaning roller 161 is retained. It will be solved by and will be in a state that is easy to remove. Thereby, the load at the time of removing the solid component of the liquid developer by which the cleaning blade 2 was compressed can be reduced. Further, the liquid developer R is held at the end of the cleaning roller 161, and the liquid ring R can be more reliably removed by contacting the photosensitive member 1 in a dry state.
Further, the squeezing roller 162 is rotated in the direction opposite to the surface moving direction of the cleaning roller 161, and the liquid developer squeezed out from the cleaning roller 161 is removed by the squeezing roller blade 162b. Accordingly, the liquid developer that has been squeezed can create a liquid flow in a direction in which gravity is easily exerted regardless of the layout of the apparatus, and the liquid developer that has been cleaned can be removed more efficiently.
Further, when the squeezing roller 162 is not in contact with the cleaning roller 161 during non-cleaning, the elastic layer 161a of the cleaning roller 161 can be prevented from being permanently deformed at the contact portion.
Further, the cleaning roller 161 during a non-cleaning by the state of non-contact with the photosensitive member 1 as an object to be cleaned body, permanent deformation at the contact portion of the elastic layer 161a chestnut over training roller 161 and the photosensitive member 1 Can be prevented.
Further, by changing the number of rotations of the cleaning roller 161 according to the residual amount of the liquid developer on the surface of the photosensitive member 1, the elastic layer 161a can maintain the state in which the liquid ring R can be absorbed and discharged. It becomes possible. Further, since the cleaning roller 161 does not absorb excessive liquid developer, it is possible to prevent the occurrence of the liquid ring R that tends to occur at the end of the cleaning roller 161.
At the end of image formation, the cleaning blade 2 is separated and the cleaning roller 161 is in contact with the photosensitive member 1, and the photosensitive member 1 and the cleaning roller 161 are driven to rotate several times. As a result, the liquid developer that could not be completely removed by only one contact of the cleaning roller 161 is completely removed by contacting the liquid developer a plurality of times. As a result, after the image formation is completed, a good standby state can be obtained.

[Modification 1]
In this embodiment, the roller-shaped diaphragm roller 162 is used as the diaphragm member. However, the present invention is not limited to this, and a blade-shaped diaphragm member may be used. Hereinafter, Modification 1 using a blade shape as the diaphragm member will be described.
FIG. 15 is an explanatory diagram of the cleaning device 16 according to the first modification. In this embodiment, a blade-shaped diaphragm blade 163 is provided instead of the cleaning roller 161 in the above-described embodiment. As shown in the figure, the squeezed liquid developer can be efficiently collected by squeezing the liquid developer held by the cleaning roller 161 in a state where the blade is set up. Further, by using the cleaning roller described in the first to third embodiments as the cleaning roller 161, the end of the cleaning roller 161 can be brought into contact with the photosensitive member 1 in a fresh state. The portion can be applied to the photoreceptor 1 in a wet state. As the material of the diaphragm blade 163 may be a resin which does not swell in a liquid used as a carrier, the carrier used in this embodiment is a silicone over N'oiru, it may be a urethane resin.

[Modification 2]
As in the first modification, a blade shape is adopted as the diaphragm member, and the contact pressure of the diaphragm member that contacts the cleaning roller 161 is set higher toward the end in the width direction of the cleaning roller 161 so that the width of the cleaning roller 161 is increased. The holding amount of the liquid developer may be varied depending on the direction. Hereinafter, modification 2 in which the contact pressure of the diaphragm blade 163 with respect to the cleaning roller 161 is set higher toward the end portion in the width direction of the cleaning roller will be described.
FIG. 16 is an explanatory diagram of the cleaning device 16 used in the second modification. FIG. 16A shows a state in which the cleaning roller 161 is in contact with the photosensitive member 1. FIG. 16B is a cross-sectional view of the cleaning roller 161 and the diaphragm blade 163 in a cross section A2 that is a cut surface of the cleaning roller end portion 161s in FIG. FIG. 16C is a cross-sectional view of the cleaning roller 161 and the diaphragm blade 163 in a cross-section A1 that is a cut surface of the cleaning roller central portion 161m in FIG. Further, FIG. 16D is a cross-sectional view of a contact portion between the cleaning roller 161 and the squeezing roller 162 in a cross section A1 which is a cut surface of the central portion of the cleaning roller 161 in FIG.
In the second modification, the cleaning roller 161 is formed of a uniform foam in the width direction, and the cross-sectional shape is also a uniform cross section in the width direction.

In the second modification, the contact pressure of the diaphragm blade 163 that contacts the cleaning roller 161 is set higher toward the end in the width direction of the cleaning roller. Specifically, as shown in FIG. 16D, the diaphragm blade 163 that contacts the cleaning roller 161 having the same cross section in the width direction is set to be longer toward the end of the cleaning roller 161.
As shown in FIG. 16B, since the length of the diaphragm blade 163 is set to be long in the cross section A2, the elastic layer 161a of the cleaning roller 161 can be appropriately crushed and held in the pores. Almost all of the liquid developer can be squeezed out and can be applied to the photoreceptor 1 in a fresh state. Further, as shown in FIG. 16C, since the length of the diaphragm blade 163 is set short in the cross section A1, the porosity is larger than the amount of the elastic layer 161a being crushed. It is possible to apply to the photosensitive member 1 while maintaining the state where the agent is held.

The elastic layer 161a on the end side of the cleaning roller 161 is in a fresh state after coming into contact with the squeezing roller 162, so that the liquid developer is easily sucked and the liquid developer that forms the liquid ring R is absorbed well. And the growth of the generated liquid ring R can be prevented. Further, the elastic layer 161a at the center of the cleaning roller 161 is in contact with the surface of the photoreceptor 1 in a state containing the liquid developer even after contact with the squeezing roller 162. In other words, the liquid developer adhesion region α is in a state where the wet porous body is in this state. As a result, the toner particles, which are solid components on the surface of the photosensitive member 1 subjected to the compression, are broken into liquid components and can be cleaned well.
Further, the aperture blade 163 is not limited to the shape shown in FIG. 16D, and the shape shown in FIGS. 16E to 16F can also be applied.

As shown in FIG. 19, the first to fourth quadrants are defined in a state where the photosensitive member 1 rotates counterclockwise, and the cleaning blade 2 and the cleaning roller 161 that contact in the counter direction are provided in each quadrant. Consider the case.
Since the cleaning effect at the contact portion of the cleaning blade 2 is determined by the rotation direction of the photosensitive member 1 and the contact direction of the cleaning blade 2, the cleaning effect of the cleaning blade 2 is not changed in any quadrant. However, in the first quadrant or the fourth quadrant, it is difficult to collect the liquid developer that has been cleaned from the surface of the photoreceptor 1 by the blade.
Usually, the recovered liquid developer gets over the cleaning blade 2, flows along the cleaning blade 2, and is received by a recovery container. However, if the cleaning blade 2 is provided in the first quadrant or the fourth quadrant, even if it is attempted to collect along the blade, the liquid needs to flow in the direction opposite to the gravity, which is difficult to implement. It is not realistic except to set up. Therefore, generally, the cleaning blade 2 is arranged in the second quadrant and the third quadrant. However, in the second quadrant, a sufficient force in the direction of gravity overcoming the thickness of the blade does not work, so there is a tendency to form a liquid ring.
Therefore, the liquid ring is positively removed using the cleaning roller 161, and the liquid developer adhering to the photosensitive member 1 is reduced.
Regarding the liquid ring, although a quantitative difference occurs depending on the quadrant in which the cleaning blade 2 is provided, it always occurs. Therefore, it is useful to provide the cleaning roller 161 in any quadrant.
In addition, by providing the cleaning roller 161 upstream of the cleaning blade 2 in the first quadrant and the fourth quadrant, the liquid developer to be collected that drips down on the surface of the photosensitive member 1 due to gravity, such as when the printer is stopped, is removed from the cleaning roller. It is also possible to collect at 161.

  As described above, the cleaning device 16 that removes the liquid developer remaining on the surface of the photosensitive member 1 as the image carrier has been described. However, the above-described configuration has the liquid remaining on the surface of the intermediate transfer drum 501 as the image carrier. The present invention can also be applied to an intermediate transfer member cleaning device 517 that removes the developer.

1 is a schematic configuration diagram of a color copying machine according to an embodiment. 1 is a schematic configuration diagram of an image forming unit of a color copying machine according to an embodiment. FIG. 3 is a schematic cross-sectional view illustrating a configuration of an intermediate roller of a coating device used in the developing device of the present embodiment. Explanatory drawing of the cleaning apparatus of the conventional photoconductor. 1 is a schematic configuration diagram of a cleaning device according to an embodiment. Explanatory drawing of the cleaning roller used by this embodiment. (A) is a perspective view of the whole cleaning roller. (B) is sectional drawing of a cleaning roller. (C) And (d) is explanatory drawing explaining the relationship between the elastic layer and cleaning roller of a cleaning roller. (A) is explanatory drawing of the contact part of a cleaning roller and a photoconductor. FIG. 6B is an explanatory diagram of a state where the squeezing roller is in contact with the cleaning roller. Explanatory drawing of each area | region when a cleaning roller is divided | segmented into the axial direction. FIG. 3 is an explanatory diagram of a cleaning roller according to the first embodiment. (A) is explanatory drawing of the cleaning roller from which a bubble rate differs continuously. (B) is an explanatory view of a cleaning roller having different bubble ratios on the inner side and the outer side at one place. (C) is an explanatory view of a state in which the aperture blade is in contact with the cleaning roller. FIG. 6 is an explanatory diagram of a cleaning roller according to Embodiment 2. (A) is explanatory drawing of the whole cleaning roller. (B) is a cross-sectional explanatory view of the end portion of the cleaning roller. FIG. 6 is an explanatory diagram of a cleaning roller according to Embodiment 3. (A) is explanatory drawing of the contact part of a cleaning roller and a photoconductor. (B) is sectional drawing of the edge part of a cleaning roller. (C) is explanatory drawing of the state which the aperture roller contact | abutted to the cleaning roller edge part. (D) is sectional drawing of the cleaning roller center part. (E) is explanatory drawing of the state which the aperture roller contacted the center part of the cleaning roller. (F) is sectional drawing of the axial direction of a cleaning roller. (G) And (h) is sectional drawing of the axial direction of the cleaning roller applicable to Example 3. FIG. Explanatory drawing of the cleaning apparatus which concerns on Example 4. FIG. (A) is explanatory drawing of the contact part of a cleaning roller and a photoconductor. (B) is sectional drawing of a cleaning roller. (C) is explanatory drawing of the state which the aperture roller contacted the cleaning roller. (D) is explanatory drawing of the state which the aperture roller contacted the cleaning roller edge part. (E) is explanatory drawing of the state which the aperture roller contacted the center part of the cleaning roller. (F) is sectional drawing of the axial direction of the cleaning roller applicable to Example 4. FIG. Explanatory drawing of the contact-and-separation mechanism with respect to the photoreceptor of a cleaning apparatus. Explanatory drawing of the contact-separation mechanism with respect to the cleaning roller of an aperture roller. FIG. 10 is an explanatory diagram of a cleaning device according to a first modification. Explanatory drawing of the cleaning apparatus which concerns on the modification 2. FIG. (A) is explanatory drawing of the contact part of a cleaning roller and a photoconductor. (B) Explanatory drawing of the state in which the aperture blade contacts the cleaning roller end. (C) is an explanatory view of a state in which the aperture blade is in contact with the central portion of the cleaning roller. (D) is explanatory drawing of the state which the aperture roller contacted the cleaning roller. (E) thru | or (g) is a perspective view of the cleaning roller applicable to the modification 2, and an aperture blade. The perspective view which shows schematic structure of the conventional cleaning apparatus. FIG. 6 is a perspective view illustrating a schematic configuration of a cleaning member described in Patent Document 1. Explanatory drawing at the time of dividing a photoconductor into the 1st-4th quadrant and providing the cleaning blade in each quadrant.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Cleaning blade 10 Transfer conveyance belt 12 Charger 16 Cleaning apparatus 17 Static elimination lamp 18 Image forming part 21 Exposure apparatus 22 Secondary transfer roller 40 Developing apparatus 42 Developing roller 47 Intermediate roller 47a Intermediate roller core 47b Intermediate roller elastic layer 161 Cleaning roller 161a Elastic layer 161b Core metal 162 Diaphragm roller 162b Diaphragm roller blade 163 Diaphragm blade 500 Transfer device 501 Intermediate transfer drum

Claims (12)

An image carrier that carries a visible image formed by a liquid developer;
Transfer means for transferring a visible image formed on the image carrier to a transfer target;
In an image forming apparatus comprising: a cleaning blade that contacts a surface of the image carrier, and a cleaning unit that collects residual liquid developer remaining on the surface of the image carrier after being transferred by the transfer unit;
Abutting against the image carrier at a width wider than at least the abutting width of the cleaning blade to the image carrier;
A foam layer capable of absorbing the liquid developer on the surface layer in contact with the image carrier,
At the abutting portion with the image carrier, a cylindrical body that rotates so that its surface moves in a direction opposite to the direction of movement of the image carrier surface is upstream of the image carrier surface movement direction of the cleaning blade. Provided in
An image forming apparatus comprising: a diaphragm member that contacts the foam layer of the cylindrical body and discharges the liquid developer absorbed by the foam layer. The image forming apparatus according to claim 1.
The cylindrical body is in contact with the foam layer at a width wider than at least the image area carrying the visible image on the surface of the image carrier;
The foam layer at the end of the cylindrical body that contacts the outside of the image area on the surface of the image carrier has the foam at the center of the cylindrical body that contacts the image area on the surface of the image carrier. An image forming apparatus, wherein the amount of liquid developer held per unit length in the width direction when passing through the contact portion with the diaphragm member is smaller than that of the body layer. The image forming apparatus according to claim 2.
An image forming apparatus, wherein the foam layer has a lower porosity toward the end in the width direction of the cylindrical body. The image forming apparatus according to claim 2 or 3,
The image forming apparatus, wherein the foam layer at least at both ends in the width direction of the cylindrical body has a single-bubble structure in which bubbles are not continuous. The image forming apparatus according to claim 2, 3 or 4,
The image forming apparatus, wherein the foam layer in contact with at least the image area of the cylindrical body has a continuous bubble structure in which bubbles are continuous. The image forming apparatus according to claim 2, 3, 4 or 5.
An image forming apparatus, wherein a thickness of the foam layer at both end portions in the width direction of the cylindrical body is formed thinner than a thickness of the foam layer in contact with the image area. The image forming apparatus according to claim 2, 3, 4, 5 or 6.
2. An image forming apparatus according to claim 1, wherein a contact pressure of the diaphragm member that contacts the cylindrical body is set to be higher toward an end in a width direction of the cylindrical body. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6 or 7.
2. The image forming apparatus according to claim 1, wherein the diaphragm member is formed of a surface moving body that moves endlessly, and the surface moves in a direction opposite to the cylindrical body at a contact portion with the cylindrical body. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7 or 8.
The cylindrical body rotates while the liquid developer is discharged by the squeezing member, and the amount of liquid that can be newly absorbed by the foam layer is the liquid development at the contact portion between the image carrier surface and the cylindrical body. An image forming apparatus, wherein the number of rotations of the cylindrical body is set so as to exceed a liquid amount of the agent. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9.
An image forming apparatus, wherein the cylindrical body is separated from the image carrier during non-cleaning. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.
The image forming apparatus, wherein the diaphragm member is separated from the cylindrical body during non-cleaning. The image forming apparatus according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.
After completion of image formation, the cleaning blade is separated from the surface of the image carrier, and the cylindrical body is in contact with the surface of the image carrier, and the image carrier and the cylindrical body are driven. Image forming apparatus.

Images