JP2009169322A - Image forming apparatus and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus free from damage to a cleaning target such an image carrier or an intermediate transfer member. <P>SOLUTION: The image forming apparatus includes: the image carrier 10Y that holds a development image formed from liquid developer containing carrier and toner particles; an image carrier cleaning roller 16Y to which a bias voltage V<SB>A</SB>is applied and which abuts on the image carrier 10Y and used to clean it; and the intermediate transfer member 40 on which the development image is transferred from the image carrier 10Y; an intermediate transfer member cleaning roller 46 to which a bias voltage V<SB>B</SB>is applied and which abuts on the intermediate transfer member 40, thereby cleaning it. The bias voltage V<SB>A</SB>and the bias voltage V<SB>B</SB>have the relation expressed by V<SB>A</SB><V<SB>B</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention comprises an image carrier on which a latent image formed on a surface is developed by a liquid developer comprising a toner and a carrier, and an intermediate transfer member on which a developed image developed from the image carrier is transferred. The present invention relates to an image forming apparatus provided with a cleaning device for cleaning, and a control method of such an image forming apparatus.

  Various wet image forming apparatuses that develop a latent image using a high-viscosity liquid developer in which a toner composed of a solid component is dispersed in a liquid solvent and visualize the electrostatic latent image have been proposed. The developer used in this wet image forming apparatus suspends solids (toner particles) in a highly viscous organic solvent (carrier liquid) having electrical insulation properties such as silicon oil, mineral oil, and edible oil. The toner particles are extremely fine with a particle diameter of around 1 μm. By using such fine toner particles, the wet image forming apparatus can achieve higher image quality than a dry image forming apparatus using powder toner particles having a particle diameter of about 7 μm.

In the image forming apparatus using the liquid developer as described above, it is necessary to provide a cleaning device for cleaning the liquid developer adhering to the rollers constituting the apparatus. As such, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2005-148239) discloses a developer carrying that carries and conveys a high-viscosity and high-concentration liquid developer in which toner is dispersed in a carrier liquid on the surface. And an electric field applying member for removing the developer by applying an electric field by the developer removing means, and a developer removing means for removing the liquid developer on the developer carrying member, and It comprises a developer removing member that contacts the developer carrier surface at an appropriate pressure downstream of the electric field applying member in the moving direction of the developer carrier surface and removes the developer by a shearing force. What is characterized by this is described.
JP 2005-148239 A

  However, the developer removal described in Patent Document 1 is intended for the developing roller, and removes the liquid developer that has not undergone the squeeze process for removing the carrier liquid. Even if a developer removing means that applies an electric field is used, the transportability of the cleaned liquid developer is not significantly impaired.

  However, in the case of using a cleaning device that removes the toner image on the image carrier or intermediate transfer member that has undergone the squeeze process by separating the carrier liquid and the toner particles with a removing means that applies an electric field, In some cases, cleaning must be performed under conditions with extremely few components, and the material properties of the object to be cleaned must also be considered. In other words, there has been a problem that, in the past, this has not been taken into account even though the conditions for operating the cleaning device differ between the image carrier and the intermediate transfer member for cleaning. It was.

SUMMARY An advantage of some aspects of the invention is that an image forming apparatus according to the present invention is applied with an image carrier that carries a developed image of a liquid developer including a carrier and toner particles, and a bias voltage _VA. An image carrier cleaning roller that contacts the image carrier, an intermediate transfer member to which a developed image is transferred from the image carrier, and an intermediate transfer that contacts the intermediate transfer member with a bias voltage V _B applied thereto. And a body cleaning roller, wherein a relationship of V _A <V _B is provided between the bias voltage V _A and the bias voltage V _B.

In addition, the image forming apparatus according to the present invention includes a first image carrier that carries a developed image by a liquid developer including a carrier and first color toner particles, and a liquid developer that includes a carrier and second color toner particles. A second image carrier carrying a developed image by the liquid, a third image carrier carrying a developed image by a liquid developer containing a carrier and third color toner particles, and a liquid containing a carrier and fourth color toner particles. and a fourth image bearing member, a first image carrier cleaning roller in contact with the first image bearing member with a bias voltage V _A1 is applied, the bias voltage V _A2 is applied which carries a developer image by a developer And a second image carrier cleaning roller that contacts the first image carrier, a third image carrier cleaning roller that is applied with a bias voltage V _A3 and contacts the first image carrier, and a bias voltage V _A4. Applied Each color from the fourth image carrier cleaning roller that contacts the first image carrier, the first image carrier, the second image carrier, the third image carrier, and the fourth image carrier. An intermediate transfer member to which the developed image is transferred, and an intermediate transfer member cleaning roller to which the bias voltage V _B is applied and in contact with the intermediate transfer member, and the bias voltage V _A1 and the bias voltage V _B between, the relationship V _A1 <V _B, the bias voltage V _A2 between the bias voltage V _B, V _A2 <the relationship V _B, the said bias voltage V _A3 bias voltage V _B between the relationship of V _A3 <V _B, between the bias voltage V _B and the bias voltage V _A4, characterized by having a relation of V _A4 <V _B.

In addition, the image forming apparatus according to the present invention includes a first image carrier that carries a developed image by a liquid developer including a carrier and first color toner particles, and a liquid developer that includes a carrier and second color toner particles. A second image carrier carrying a developed image by the liquid, a third image carrier carrying a developed image by a liquid developer containing a carrier and third color toner particles, and a liquid containing a carrier and fourth color toner particles. and a fourth image bearing member, a first image carrier cleaning roller in contact with the first image bearing member with a bias voltage V _A1 is applied, the bias voltage V _A2 is applied which carries a developer image by a developer And a second image carrier cleaning roller that contacts the first image carrier, a third image carrier cleaning roller that is applied with a bias voltage V _A3 and contacts the first image carrier, and a bias voltage V _A4. Applied Each color from the fourth image carrier cleaning roller that contacts the first image carrier, the first image carrier, the second image carrier, the third image carrier, and the fourth image carrier. And an intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member, and the bias voltage V _{A1 and the} bias voltage V _A2 Between the bias voltage V _A3 , the bias voltage V _A4 and the bias voltage V _B , there are relationships of V _A1 <V _A4 , V _A2 <V _A4 , V _A3 <V _A4 , V _A4 <V _B. It is characterized by.

  The image forming apparatus according to the present invention includes an image carrier cleaning blade that abuts on the image carrier and an intermediate transfer body cleaning blade that abuts on the intermediate transfer body.

  The image forming apparatus according to the present invention is characterized in that the intermediate transfer member has an elastic layer.

  In the image forming apparatus according to the present invention, an angle at which the image carrier cleaning blade contacts the image carrier is larger than an angle at which the intermediate transfer member cleaning blade contacts the intermediate transfer member. .

The image forming apparatus control method according to the present invention includes an image carrier that carries a developed image with a liquid developer containing carriers and toner particles, and a bias voltage V _{A that} is applied to the image carrier. An image having an image carrier cleaning roller in contact, an intermediate transfer member to which a developed image is transferred from the image carrier, and an intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member In the control method of the forming apparatus, when the relationship of V _A <V _B is given between the bias voltage V _A and the bias voltage V _B and the developing conditions are different, the image carrier cleaning roller and a bias voltage V _a to be applied to, and controls to change the bias voltage V _B to be applied to the intermediate transfer member cleaning roller.

  The image forming apparatus control method according to the present invention is characterized in that the development conditions are different when the types of recording media to be developed are different.

  As described above, according to the present invention, the conditions for operating the cleaning device are set according to the material properties of the object to be cleaned (image carrier, intermediate transfer member). There is no fear of destroying the cleaning object such as the body.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing main components constituting the image forming apparatus according to the embodiment of the present invention. The developing devices 30Y, 30M, 30C, and 30K are arranged at the lower portion of the image forming apparatus with respect to the image forming units of the respective colors arranged at the center of the image forming apparatus, and the intermediate transfer body 40 and the secondary transfer unit (secondary transfer unit) The transfer unit 60 is disposed on the upper part of the image forming apparatus. A configuration below the intermediate transfer member 40 in FIG. 1 is referred to as an image forming unit.

  The image forming unit includes image carriers 10Y, 10M, 10C, and 10K, corona chargers 11Y, 11M, 11C, and 11K, and exposure units 12Y, 12M, 12C, and 12K (not shown). The exposure units 12Y, 12M, 12C, and 12K have optical systems such as a semiconductor laser, a polygon mirror, and an F-θ lens. The image carriers 10Y, 10M, 10C, and 10C are provided by corona chargers 11Y, 11M, 11C, and 11K. 10K is uniformly charged, and the exposed image carriers 10Y, 10M, 10C, and 10K are irradiated with a modulated laser beam based on the input image signal by the exposure units 12Y, 12M, 12C, and 12K. An electrostatic latent image is formed on 10K.

  The developing devices 30Y, 30M, 30C, and 30K generally include liquid developers of respective colors including the developing rollers 20Y, 20M, 20C, and 20K, yellow (Y), magenta (M), cyan (C), and black (K). Developer containers (reservoirs) 31Y, 31M, 31C, 31K to be stored, and application rollers for applying liquid developers of these colors from the developer containers 31Y, 31M, 31C, 31K to the developing rollers 20Y, 20M, 20C, 20K. The anilox rollers 32Y, 32M, 32C, and 32K are provided, and the electrostatic latent images formed on the image carriers 10Y, 10M, 10C, and 10K are developed with the liquid developers of the respective colors.

  The intermediate transfer member 40 is an endless belt, and is stretched around a driving roller 41 and tension rollers 42, 52, and 53. The image transfer members 10Y, 10M, 10C, and 10K are primary transfer units 50Y, 50M, 50C, and 50K. It is rotationally driven by the driving roller 41 while abutting. The primary transfer units 50Y, 50M, 50C, and 50K are arranged such that the primary transfer rollers 51Y, 51M, 51C, and 51K are opposed to each other with the image transfer bodies 10Y, 10M, 10C, and 10K sandwiched between the intermediate transfer body 40 and the image transfer bodies 10Y, Using the contact position with 10M, 10C, and 10K as the transfer position, the developed toner images of the respective colors on the image carriers 10Y, 10M, 10C, and 10K are sequentially superimposed and transferred onto the intermediate transfer body 40 to obtain a full-color toner. Form an image.

  In the secondary transfer unit 60, a secondary transfer roller 61 is disposed opposite to the belt driving roller 41 with the intermediate transfer body 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 is disposed. Then, at the transfer position where the secondary transfer roller 61 is disposed, a single color toner image or a full color toner image formed on the intermediate transfer body 40 is conveyed on the sheet material conveyance path L such as paper, film, cloth, etc. Transfer to recording medium.

  Further, a fixing unit (not shown) is disposed downstream of the path sheet material conveyance path L, and a single color toner image or a full color toner image transferred onto a recording medium such as paper is fused to the recording medium such as paper. And fix.

  In the present embodiment, a paper type determination sensor 5 as shown in FIG. 1 is provided to detect the type of recording medium. This paper type determination sensor 5 is formed of a light emitting element 6 that irradiates light to a recording medium conveyed through the conveying path, and a light receiving element 7 that detects reflection of reflected light from the recording medium. In the present embodiment, a signal such as the reflectance of reflected light from the light receiving element 7 is input to a control unit such as a CPU (not shown), and the paper type of the recording medium (art paper, coated paper, fine paper, plain paper, etc.) Type) is determined.

  Further, the tension roller 42 stretches the intermediate transfer body 40 together with the belt drive roller 41, and a cleaning device including the intermediate transfer body cleaning roller 46 at a portion stretched on the tension roller 42 of the intermediate transfer body 40. Are abutting and arranged.

  In general, among the yellow (Y), magenta (M), cyan (C), and black (K) image forming units of the image forming apparatus configured as described above, the YMC image forming unit is not shown. It is configured to be displaced up and down by a separation / contact mechanism, so that it can come into contact / contact with the intermediate transfer member 40. Due to such a configuration, the image forming apparatus of the present invention allows the YMC image forming unit to be separated from the intermediate transfer body 40 during single color printing using only black, which is frequently used. Color mixing in can be reduced as much as possible.

  Next, the image forming unit and the cleaning device of the image forming apparatus according to the embodiment of the present invention will be described. FIG. 2 is a sectional view showing main components of the image forming unit and the cleaning device. Since the configurations of the image forming unit and the developing device for each color are the same, the following description is based on the yellow (Y) image forming unit and the developing device.

  The image forming unit includes an image carrier cleaning roller 16Y, an image carrier cleaning blade 18Y, a corona charger 11Y, an exposure unit 12Y, a developing roller 20Y of the developing device 30Y, an image along the rotation direction of the outer periphery of the image carrier 10Y. Carrier squeeze rollers 13Y and 13Y ′ are arranged.

The image carrier cleaning roller 16Y is a roller having a urethane rubber surface layer, and rotates counterclockwise while being in contact with the image carrier 10Y, so that the untransferred liquid developer or the untransferred liquid developer on the image carrier 10Y. To clean. _A bias voltage V _A that attracts toner particles in the liquid developer is applied to the image carrier cleaning roller 16Y. Therefore, what is collected by the image carrier cleaning roller 16Y is a liquid developer containing a large amount of toner particles. The liquid developer rich in solid content collected by the image carrier cleaning roller 16Y is scraped off by the image carrier cleaning roller cleaning blade 17Y contacting the image carrier cleaning roller 16Y and falls vertically downward.

  In contrast, the image carrier cleaning blade 18Y that is in contact with the image carrier 10Y on the downstream side of the image carrier cleaning roller 16Y removes the liquid developer rich in carrier components on the image carrier 10Y with the cleaning blade. It is dropped downward through the holding member 73Y.

  The term “solid content rich” refers to a state of a liquid developer that contains more solid content than the liquid developer supplied to the developing device 30Y. On the other hand, the carrier component rich means a state of a liquid developer containing a larger amount of carrier component than the liquid developer supplied to the developing device 30Y. The liquid developer (toner) can be defined as a solid content (toner particles) dispersed in a carrier.

  In the cleaning blade holding member 73Y, both the liquid developer rich in solid content dropped from the image carrier cleaning roller cleaning blade 17Y and the liquid developer rich in carrier component scraped by the image carrier cleaning blade 18Y are mixed. The fit improves the transportability. Further, such improvement in transportability can also contribute to downsizing of the apparatus.

  The image carrier recovery storage unit 80Y includes a solid developer rich liquid developer scraped by the image carrier cleaning roller cleaning blade 17Y and a carrier component rich liquid developer scraped by the image carrier cleaning blade 18Y. It has a concave part that receives both.

  A collecting screw 81Y is provided in the concave portion of the image carrier collecting and storing unit 80Y. When the collecting screw 81Y rotates, the liquid developer received by the spiral blade at the concave portion is collected on the rotating shaft of the collecting screw 81Y. Transport in the direction. The liquid developer conveyed by the recovery screw 81Y is sent to a recovery mechanism (not shown).

  Reference numerals 70Y, 71Y, 72Y, 73Y denote cleaning blade holding members for holding the cleaning blades.

  Further, the image carrier cleaning blade 18Y comes into contact with and separates from the image carrier 10Y by a cleaning blade contact / separation mechanism (not shown). In this embodiment, the surface photoreceptor of the image carrier 10Y is formed of amorphous silicon, and the toner remaining on the image carrier 10 without being cleaned is charged by friction with the image carrier cleaning blade 18Y. There is a possibility of destroying the image carrier 10Y made of amorphous silicon. Therefore, in the image forming apparatus of the present invention, when a large amount of toner image remains on the image carrier 10Y and is cleaned when printing is interrupted due to a paper jam or the like, the image carrier cleaning blade 18Y is separated. This is a simple process.

  A similar cleaning blade contact / separation mechanism is also provided in an intermediate transfer member cleaning blade 49 that cleans the intermediate transfer member 40. FIG. 3 is a view for explaining the contact and separation of the intermediate transfer member cleaning blade in the present invention, and FIG. 4 is a view for explaining the structure of the intermediate transfer member in the present invention.

  The intermediate transfer member cleaning blade 49 is configured so as to be able to come into and out of contact with the intermediate transfer member 40 by a contact and separation mechanism (not shown). As shown in FIG. 4, as the intermediate transfer member 40, for example, a polyurethane rubber elastic layer (JIS-A 30 degrees) having a thickness of 200 μm is formed on a polyimide substrate layer having a thickness of 100 μm, and further on the polyurethane base layer. A three-layer endless belt having a surface coating of a fluororesin coating layer such as PFA having a thickness of 10 μm is used.

  When a paper jam or the like occurs, a large amount of toner remains on the intermediate transfer member 40, and when the toner is to be removed, the intermediate transfer member is affected by the large amount of toner that the intermediate transfer member cleaning blade 49 tries to scrape off. In the case where there is a possibility of breaking 40, the intermediate transfer member cleaning blade 49 is separated from the intermediate transfer member 40 by the contact / separation mechanism. During normal printing, the intermediate transfer member cleaning blade 49 is brought into contact with the intermediate transfer member 40.

  In the initial operation when the image forming apparatus is activated, when a predetermined amount of carrier is supplied onto the intermediate transfer member 40, the intermediate transfer member cleaning blade 49 is in contact with the intermediate transfer member 40. Since this cannot be performed, the intermediate transfer member cleaning blade 49 is separated from the intermediate transfer member 40 by the contact / separation mechanism.

  FIG. 5 is a diagram showing an example of the arrangement of the cleaning device according to the present invention. 5A and 5B both show the cleaning device of the present invention, but the contact positions of the image carrier cleaning roller cleaning blade 17Y and the image carrier cleaning blade 18Y are different.

  In the cleaning device according to the present invention, the position where the image carrier cleaning roller cleaning blade 17Y contacts the image carrier cleaning roller 16Y is a lower half position when viewed from the gravity direction of the image carrier cleaning roller 16Y as shown in FIG. It is desirable to do. This is because the liquid developer scraped by the image carrier cleaning roller cleaning blade 17Y can be dropped without being transmitted to the image carrier cleaning roller 16Y.

  The liquid developer scraped by the image carrier cleaning roller cleaning blade 17Y is dropped on the cleaning blade holding member 73Y in the example shown in FIG. 5A, whereas the example shown in FIG. 5B. Then, it is dropped directly into the concave portion of the image carrier collection / reservoir 80Y.

  Since the liquid developer scraped off by the image carrier cleaning roller cleaning blade 17Y is a solid developer rich in solids and has a large amount of solid components, the transportability when transporting the liquid developer in the direction of the rotation axis of the recovery screw 81Y is improved. Not good. 5A, the liquid developer scraped by the image carrier cleaning blade 18Y is merged with the carrier developer-rich liquid developer on the cleaning blade holding member 73Y. There is an advantage that the transportability of the recovered liquid developer is improved. Therefore, the handleability in the image carrier collection / reservoir 80Y is improved. Here, an example is shown in which the liquid developer scraped off by the image carrier cleaning roller cleaning blade 17Y falls on the cleaning blade holding member 73Y, but it may be dropped directly on the image carrier cleaning blade 18Y. Good.

  In such a configuration of the present embodiment, both the liquid developer cleaned by the image carrier cleaning roller cleaning blade 17Y and the liquid developer cleaned by the image carrier cleaning blade 18Y are supplied to the image carrier recovery storage unit 80Y. The recovered material collected by the image carrier cleaning roller 16Y, which is likely to have a relatively high solid content (toner component) concentration by being collected by the image carrier, is collected by the image carrier cleaning roller cleaning blade 18Y and is rich in the carrier component. In addition, it is easy to transport the collected material collected by the image carrier cleaning roller 16Y, which tends to have a relatively high solid content concentration, and the size of the apparatus can be reduced.

  In the present embodiment, since the carrier used for the liquid developer is a non-volatile carrier, the solid developer rich liquid developer scraped by the image carrier cleaning roller cleaning blade 18Y and the image carrier cleaning blade 18Y are used. It is possible to improve the transportability by combining the liquid developer rich in the carrier component that is scraped off.

  In this embodiment, the surface layer of the image carrier 10 is formed of amorphous silicon. In such an amorphous silicon surface layer, the toner remaining after the transfer is frictionally charged with a contact object such as a blade and destroyed. The phenomenon of being easy to occur. In the present embodiment, the surface of the image carrier 10 is not destroyed because the cleaning is performed with the configuration centering on the image carrier cleaning roller 16Y as described above in the downstream of the transfer.

  A cleaning blade 21Y, an anilox roller 32Y, and a compaction corona generator 22Y are disposed on the outer periphery of the developing roller 20Y in the developing device 30Y. A regulating blade 33Y for adjusting the amount of liquid developer supplied to the developing roller 20Y is in contact with the anilox roller 32Y. A blade holding member 75Y holds the regulating blade 33Y. An auger 34Y and a recovery screw 321Y are accommodated in the liquid developer container 31Y.

  A primary transfer roller 51Y of the primary transfer portion is disposed along the intermediate transfer body 40 at a position facing the image carrier 10Y.

  The image carrier 10Y is a photosensitive drum made of a cylindrical member that is wider than the developing roller 20Y and has a photosensitive layer formed on the outer peripheral surface thereof. For example, the image carrier 10Y rotates in a clockwise direction as shown in FIG. The surface photosensitive layer of the image carrier 10Y is composed of an amorphous silicon image carrier. The corona charger 11Y is disposed upstream of the nip portion between the image carrier 10Y and the developing roller 20Y in the rotation direction of the image carrier 10Y, and a voltage is applied from a power supply device (not shown) to charge the image carrier 10Y. Let The exposure unit 12Y irradiates a laser beam onto the image carrier 10Y charged by the corona charger 11Y on the downstream side in the rotation direction of the image carrier 10Y from the corona charger 11Y, and a latent image is formed on the image carrier 10Y. Form.

  Note that, from the beginning to the end of the image forming process, the configuration of the rollers and the like arranged in the preceding stage is defined as being upstream of the configuration of the rollers and the like arranged in the subsequent stage.

  The developing device 30Y includes a compaction corona generator 22Y that performs a compaction action, and a developer container 31Y that stores a liquid developer in a state where toner is dispersed in a carrier at a weight ratio of approximately 20%. The developer container 31Y is also provided with a recovery screw 321Y that recovers the liquid developer that has not been supplied to the anilox roller 32Y.

  The developing device 30Y also includes a developing roller 20Y that carries the liquid developer, an anilox roller 32Y that is a coating roller for applying the liquid developer to the developing roller 20Y, and the amount of liquid developer that is applied to the developing roller 20Y. A regulating blade 33Y for regulating, an auger 34Y supplying the anilox roller 32Y while stirring and conveying the liquid developer, a compaction corona generator 22Y for bringing the liquid developer carried on the developing roller 20Y into a compacted state, and a developing roller 20Y A developing roller cleaning blade 21Y that performs the above cleaning. A cleaning blade holding member 76Y holds the developing roller cleaning blade 21Y.

  The liquid developer contained in the developer container 31Y is a low-concentration (about 1 to 2 wt%) and low-viscosity volatile at room temperature using a conventionally used Isopar (trademark: exon) as a carrier. Is a non-volatile liquid developer having a high concentration and high viscosity and having non-volatility at room temperature. That is, in the liquid developer in the present invention, a solid having an average particle diameter of 1 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin is introduced into a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil. It is a liquid developer having a high viscosity (about 30 to 10,000 mPa · s) which is added together with a dispersant and has a toner solid content concentration of about 20%.

  The auger 34Y is provided in the liquid developer container 31Y so as to be separated from the anilox roller 32Y. When the auger 34Y rotates counterclockwise in FIG. 2, the liquid developer is supplied to the anilox roller 32Y. It has become so. FIG. 6 is a diagram illustrating a state (A) when the image forming apparatus according to the present invention is stopped and a state (B) when the image forming apparatus is operating. In FIG. 6, 31Y is a developer container, 32Y is an aniloc roller, 33Y is a restriction blade, 75Y is a restriction blade holding member, 34Y is an auger, 310Y is a supply storage section, 320Y is a collection storage section, 321Y is a collection screw, 330Y Denotes a partition part, 360Y denotes a liquid developer supply member, 365Y denotes a liquid developer supply port, 370Y denotes a liquid developer supply pipe, and 371Y denotes a liquid developer recovery pipe.

  The space in the developing container 31Y is divided into two by a partition portion 330Y. One of the spaces divided by the partition unit 330Y is used as a supply storage unit 310Y for supplying the liquid developer, and the other is used as a recovery storage unit 320Y for recovering the liquid developer. The supply storage unit 310Y and the collection storage unit 320Y are separated by the partition unit 330Y so as to be parallel to each other in the axial direction.

  An auger 34Y is rotatably provided in the supply storage unit 310Y, and the liquid developer stored in the supply storage unit 310Y is supplied to the anilox roller 32Y when the auger 34Y rotates during operation of the apparatus. The supply storage unit 310Y and the liquid developer supply pipe 370Y are connected, and the supply of the liquid developer to the supply storage unit 310Y is performed by the liquid developer supply pipe 370Y.

  In addition, a collection screw 321Y is rotatably provided in the collection storage unit 320Y, and the collection screw 321Y rotates during operation of the apparatus, so that liquid developer that has not been used for development or an image carrier squeeze roller cleaning blade. The carrier dropped from the cleaning blade such as 14Y and 14Y ′ is collected.

  The collection storage unit 320Y and the liquid developer collection pipe 371Y are connected to each other. When the collection screw 321Y rotates, the liquid developer is supplied to one end of the collection storage unit 320Y to which the liquid developer collection pipe 371Y is connected. It is designed to be transported. The liquid developer recovered by the recovery storage unit 320Y in this way is guided to a liquid developer recycling mechanism (not shown) by the liquid developer recovery pipe 371Y.

The partition portion 330Y is formed with a region having a _first height (H ₁ ) and a region having a second height (H ₂ ) that are different in the axial direction. In the present embodiment, the first height (H ₁ ) region is set at the center of the partition portion 330Y, and the second height (H ₂ ) region is set at both ends of the partition portion 330Y. The first height (H ₁ ) is set higher than the second height (H ₂ ).

The area of the first height (H ₁ ) of the partition portion 330Y blocks the liquid developer surface by blocking the liquid developer that tends to move toward the collection storage portion 320Y by the rotation of the auger 34Y during operation of the apparatus. It works to lift. That is, the first height (H ₁ ) region is provided so that the liquid developer can be conveyed from the auger 34Y to the anilox roller 32Y only when the auger 34Y is rotating.

The second height (H ₂ ) region of the partition portion 330Y determines the liquid level of the liquid developer in the supply storage portion 310Y when the apparatus is stopped. Further, during operation of the apparatus, a path is provided for flowing the liquid developer that is steadily supplied from the liquid developer supply pipe 370Y to the supply storage unit 310Y toward the collection storage unit 320Y.

The region of the second height (H ₂ ) of the partition portion 330Y has a role of determining the liquid level of the liquid developer in the supply storage portion 310Y when the apparatus is stopped. The anilox roller 32Y is prevented from being immersed in the liquid developer.

FIG. 7 shows the flow of the liquid developer when the axial direction of the rollers is viewed from the side. During the operation of the apparatus, the liquid developer supplied from the liquid developer supply port 365Y to the supply storage unit 310Y is liquid developer in the first height (H ₁ ) region due to the rotation of the auger 34Y (not shown). As the liquid level rises, in the region of the _second height (H ₂ ), it moves beyond the partition 330Y to move from the supply reservoir 310Y to the recovery reservoir 320Y. Further, the liquid developer supplied at the approximate center of the supply storage unit 310Y is conveyed by the auger 34Y to the left and right of the drawing. The liquid developer supplied from the liquid developer supply port 365Y to the supply storage unit 310Y is adjusted to a constant density by a mechanism (not shown).

  In the collection storage unit 320Y, the liquid developer is conveyed from the left side to the right side by a collection screw 321Y (not shown), and is guided from the liquid developer collection pipe 371Y to a developer recycling mechanism (not shown).

  The anilox roller 32Y functions as an application roller that supplies and applies a liquid developer to the developing roller 20Y. FIG. 8 is a perspective view of an aniloc roller used in the present invention. The anilox roller 32Y is a cylindrical member, and is a roller having a concave and convex surface formed by grooves engraved in a fine and uniform spiral shape on the surface so that the developer can be easily carried on the surface. The anilox roller 32Y supplies the liquid developer from the developer container 31Y to the developing roller 20Y. During operation of the apparatus, as shown in FIG. 2, the auger 34Y rotates clockwise to supply the liquid developer to the aniloc roller 32Y, and the aniloc roller 32Y rotates counterclockwise to the developing roller 20Y. Apply liquid developer.

  The regulation blade 33Y is an elastic blade having a surface coated with an elastic body, and is composed of a rubber portion made of urethane rubber or the like that comes into contact with the surface of the anilox roller 32Y, and a plate of metal or the like that supports the rubber portion. The Then, the film thickness and amount of the liquid developer carried and conveyed by the anilox roller 32Y are regulated and adjusted, and the amount of liquid developer supplied to the developing roller 20Y is adjusted.

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

  The compaction corona generator 22Y is an electric field applying means that increases the charging bias on the surface of the developing roller 20Y. The liquid developer conveyed by the developing roller 20Y is compacted by the compaction corona generator 22Y as shown in FIG. Thus, an electric field is applied from the compaction corona generator 22Y side toward the developing roller 20Y.

  As the electric field applying means for compaction, a compaction roller or the like may be used instead of the corona discharge of the corona discharger shown in FIG. Such a compaction roller is a cylindrical member, is in the form of an elastic roller that is configured by covering an elastic body in the same manner as the developing roller 20Y, and has a conductive resin layer or rubber layer on the surface layer of the metal roller base material. For example, it may be rotated clockwise in the opposite direction to the developing roller 20Y.

  On the other hand, the developer carried on the developing roller 20Y and compacted is developed corresponding to the latent image on the image carrier 10Y by applying a desired electric field at the development nip where the developing roller 20Y contacts the image carrier 10Y. Is done. The developer remaining after development is scraped off and removed by the developing roller cleaning blade 21Y and dropped into the collecting unit in the developer container 31Y for reuse. The carrier and toner that are reused in this way are not in a mixed color state.

  The image carrier squeeze device disposed on the upstream side of the primary transfer collects excess developer of the toner image that is disposed on the downstream side of the developing roller 20Y so as to face the image carrier 10Y and is developed on the image carrier 10Y. As shown in FIG. 2, the image carrier squeeze rollers 13Y and 13Y ′, each of which comprises an elastic roller member whose surface is covered with an elastic member and rotates in sliding contact with the image carrier 10Y, and the image carrier squeeze The cleaning blades 14Y and 14Y ′ are configured to clean the surface by pressing and sliding against the rollers 13Y and 13Y ′. The excess carrier and the originally unnecessary fog toner are collected from the developer developed on the image carrier 10Y to be exposed. It has a function of increasing the toner particle ratio in the image. As the image carrier squeeze device before the primary transfer, a plurality of image carrier squeeze rollers 13Y and 13Y 'are provided in this embodiment, but they may be constituted by one image carrier squeeze roller. Further, one of the plurality of image carrier squeeze rollers 13Y and 13Y 'may be configured to come into contact with and come into contact with each other according to the state of the liquid developer.

  In the primary transfer unit 50Y, the developer image developed on the image carrier 10Y is transferred to the intermediate transfer member 40 by the primary transfer roller 51Y. Here, the image carrier 10Y and the intermediate transfer member 40 are configured to move at a constant speed, reducing the driving load of rotation and movement, and suppressing the disturbance effect on the visible toner image of the image carrier 10Y. Yes.

  The intermediate transfer member 40 passes through the nip of the primary transfer portion 50 of each color of yellow (Y), magenta (M), cyan (C), and black (K), and the developed image of the image carrier of each color is transferred to the color overlay. Then, it enters the nip portion of the secondary transfer unit 60.

  FIG. 9 is a diagram showing the configuration of the cleaning device in the secondary transfer unit. The secondary transfer unit 60 is formed on the intermediate transfer body 40 at a transfer position where the secondary transfer roller 61 is disposed so that the secondary transfer roller 61 faces the belt driving roller 41 with the intermediate transfer body 40 interposed therebetween. The single-color toner image or full-color toner image thus formed is transferred to a recording medium such as paper, film, or cloth conveyed through the sheet material conveyance path L.

  A secondary transfer roller cleaning blade 62 is in contact with the secondary transfer roller 61 and scrapes off the liquid developer adhering to the secondary transfer roller 61. In particular, the cleaning by the secondary transfer roller cleaning blade 62 is useful when the recording medium that is supposed to be transported does not reach the secondary transfer position due to a paper jam or the like. When the secondary transfer is successfully executed, the secondary transfer roller cleaning blade 62 mainly scrapes off the carrier component. Reference numeral 74 denotes a secondary transfer roller cleaning blade holding member.

  The liquid developer scraped off by the secondary transfer roller cleaning blade 62 travels down the secondary transfer roller cleaning blade holding member 74 and falls. The dropped liquid developer is received by the secondary transfer unit recovery storage portion 85 having a concave portion, and is conveyed in the direction of the rotation axis by the rotation of the recovery screw 86 provided in the concave portion. The collection screw 86 has spiral wings and the like, and with the rotation thereof, the liquid developer can be conveyed in the axial direction. The liquid developer conveyed by the recovery screw 86 is sent to a recovery mechanism (not shown).

  The intermediate transfer body 40 that has passed through the secondary transfer unit 60 circulates again to receive the transfer image at the primary transfer unit 50, but cleaning of the intermediate transfer body 40 is performed on the upstream side where the primary transfer unit 50 is executed. . FIG. 10 is a diagram showing the configuration of an intermediate transfer member cleaning device.

An intermediate transfer body cleaning roller 46 is provided so as to contact the intermediate transfer body 40 while facing the tension roller 42. The intermediate transfer member cleaning roller 46 is a roller having a urethane rubber surface layer, and a bias voltage V _B that attracts toner particles in the liquid developer is applied to the intermediate transfer member cleaning roller 46. Yes. The intermediate transfer member cleaning roller 46 rotates clockwise while being in contact with the intermediate transfer member 10, thereby attracting and cleaning the liquid developer (mainly toner particles) remaining on the intermediate transfer member 40 by a bias voltage. This bias voltage V _B is set higher than the bias voltage V _A applied to the image carrier cleaning roller 16. This is because the adhesive force of the toner component of the liquid developer is higher in the intermediate transfer body 40 than in the image carrier 10.

  The intermediate transfer body cleaning roller 46 is in contact with an intermediate transfer body cleaning roller cleaning blade 47 at a lower half position when viewed from the gravity direction of the intermediate transfer body cleaning roller 46. Then, the liquid developer recovered by the intermediate transfer member cleaning roller 46 is scraped off. The liquid developer scraped off by the intermediate transfer member cleaning roller cleaning blade 47 falls vertically downward.

  On the downstream side of the intermediate transfer member cleaning roller 46, an intermediate transfer member cleaning blade 49 is provided that contacts and cleans the intermediate transfer member 40. Reference numerals 77 and 78 denote cleaning blade holding members for holding the cleaning blade. Further, as described above, the intermediate transfer member cleaning blade 49 is provided with a contact / separation mechanism (not shown) so that the intermediate transfer member cleaning blade 49 contacts and contacts the intermediate transfer member 40.

  Further, the intermediate transfer member collection and storage unit 87 includes a solid developer rich liquid developer scraped by the intermediate transfer member cleaning roller cleaning blade 47 and a carrier component rich liquid developer scraped by the intermediate transfer member cleaning blade 49. , And has a concave portion that receives both of the above.

  A recovery screw 88 is provided in the concave portion of the intermediate transfer body recovery storage portion 87, and when the recovery screw 88 rotates, the liquid developer received by the spiral blade in the concave portion is collected by the recovery screw 88 rotating shaft. Transport in the direction. The liquid developer conveyed by the recovery screw 88 is sent out to a recovery mechanism (not shown).

  Since the liquid developer scraped off by the intermediate transfer member cleaning roller cleaning blade 47 is a liquid developer rich in solids and has a large amount of solid components, the transportability when transporting the liquid developer in the direction of the rotation axis of the recovery screw 88 is improved. Not good. Therefore, when the arrangement relationship as shown in FIG. 10 is adopted, the liquid developer scraped by the intermediate transfer member cleaning blade 49 is combined with the carrier developer-rich liquid developer on the cleaning blade holding member 78 and collected. There is an advantage that the transportability of the liquid developer is improved. Therefore, the handling property in the intermediate transfer member collection and storage unit 87 is improved. Here, an example in which the liquid developer scraped off by the intermediate transfer member cleaning roller cleaning blade 47 falls on the cleaning blade holding member 78 is shown, but it may be dropped directly on the intermediate transfer member cleaning blade 49. Good.

  The cleaning blade holding member 68 is mixed with both the solid developer rich liquid developer dropped from the intermediate transfer member cleaning roller cleaning blade 47 and the carrier component rich liquid developer scraped by the intermediate transfer member cleaning blade 49. The fit improves the transportability. Further, such improvement in transportability can also contribute to downsizing of the apparatus.

  The intermediate transfer body 40 has a three-layer structure in which an elastic intermediate layer of polyurethane rubber is provided on a polyimide base layer, and a PFA surface layer is provided thereon. Such an intermediate transfer body 40 is used in such a manner that it is stretched by a driving roller 41 and tension rollers 42, 52, 53 on the polyimide base layer side, and a toner image is transferred on the PFA surface layer side.

  The intermediate transfer body 40 having elasticity thus formed has good followability and responsiveness to the surface of the recording medium. This is effective for feeding and transferring.

As described above, the intermediate transfer body 40 has elasticity and cannot be brought into contact with a blade for cleaning with a strong pressure. In the present embodiment, the intermediate transfer body 40 to which the bias voltage V _B is applied is used. Since the structure in which the intermediate transfer body 40 is cleaned with the roller structure of the body cleaning roller 46 is employed, there is no possibility of damaging the intermediate transfer body 40 having elasticity.

Next, the relationship between the bias voltage V _A applied to the image carrier cleaning roller 16Y and the bias voltage V _B applied to the intermediate transfer member cleaning roller 46 will be described. First, as shown in FIG. 1, the case where the YMC image forming unit is separated from the intermediate transfer member 40 by the contact / separation mechanism will be described.

The relationship between the bias voltage V _A4 (= V _A ) applied to the image carrier cleaning roller 16Y and the bias voltage V _B applied to the intermediate transfer member cleaning roller 46 in such a case is as shown in FIG. Become. That is, a bias voltage is applied to each roller so that V _A4 (= V _A ) <V _B.

In this way, the bias voltage V _B is set higher than the bias voltage V _A4 (= V _A ). This is because the toner particles of the residual liquid developer on the intermediate transfer body 40 removed by the intermediate transfer body cleaning roller 46 are: The toner passes through the nip of the secondary transfer unit 60 and adheres more firmly than the toner particles of the liquid developer on the image carrier 10, and a higher bias voltage is applied to remove the liquid developer. Because you have to do it.

  As described above, in the present embodiment, the bias voltage of the cleaning device is set according to the adhesion of the toner particles in the liquid developer on the intermediate transfer body 40 and the image carrier 10. It becomes possible to perform cleaning appropriately according to the state.

Next, setting of bias voltage application in another image forming apparatus of the present embodiment will be described. FIG. 12 is a view showing main components constituting an image forming apparatus according to another embodiment of the present invention. The image forming apparatus described with reference to FIGS. 1 and 2 can form a color image, whereas the image forming apparatus shown in FIG. 12 has a monochrome image forming unit. In the drawing, the same reference numerals as those in the previous embodiment denote the same components as in the previous embodiment. In the image forming apparatus of FIG. 12, since there is no difference such as YMCK, a subscript for indicating YMCK is omitted. Further, as the bias voltage, it is assumed that the bias voltage V _A is applied to the image carrier cleaning roller 16 and the bias voltage V _B is applied to the intermediate transfer member cleaning roller 46. Also in an image forming apparatus handling monochromatic toner as shown in FIG. 12, a bias voltage set as V _A <V _B as shown in FIG. 11 is applied. The reason for this setting is that the toner particles on the intermediate transfer member 40 adhere more firmly than the toner particles on the image carrier 10.

Next, the bias voltage V _A1 , bias voltage V _A2 , bias voltage V _A3 , bias voltage V _A4 applied to the image carrier cleaning rollers 16Y, 16M, 16C, and 16K, and the intermediate transfer member cleaning roller 46, respectively. The relationship with the bias voltage V _B will be described. This relates to the setting in the embodiment shown in FIG. 1 when the YMC image forming unit is in contact with the intermediate transfer member 40 by the contact / separation mechanism.

In this way, when the YMC image forming unit is in contact, the bias voltages V _A1 , V _A2 , V _A3 , V _A4 applied to each image carrier cleaning roller 16 and the intermediate transfer member cleaning roller 46 are applied. The relationship with the bias voltage V _B is as shown in FIG. That is, a bias voltage is applied to each roller so that V _A1 <V _B , V _A2 <V _B , V _A3 <V _B , V _A4 <V _B.

In this way, the bias voltage V _B is set higher than any of the bias voltages V _A1 , V _A2 , V _A3 , V _A4 , and this is a residual liquid on the intermediate transfer member 40 that is removed by the intermediate transfer member cleaning roller 46. The toner particles of the developer have passed through the nip of the secondary transfer unit 60, and adhere more firmly than the toner particles of the liquid developer on any of the image carriers 10, and a higher bias voltage than that. This is because the liquid developer has to be removed by applying.

  As described above, in the present embodiment, the bias voltage of the cleaning device is set according to the adhesion of the toner particles in the liquid developer on the intermediate transfer body 40 and the image carrier 10. It becomes possible to perform cleaning appropriately according to the state.

Next, the bias voltage V _A1 , bias voltage V _A2 , bias voltage V _A3 , bias voltage V _A4 applied to the image carrier cleaning rollers 16Y, 16M, 16C, and 16K, and the intermediate transfer member cleaning roller 46, respectively. The relationship with the bias voltage V _B will be described. This relates to the setting in the embodiment shown in FIG. 1 when the YMC image forming unit is in contact with the intermediate transfer member 40 by the contact / separation mechanism. Furthermore, the present embodiment is an example in which the setting of the bias voltage is changed depending on the difference in electrical characteristics of YMCK toner particles.

In this way, when the YMC image forming unit is in contact, the bias voltages V _A1 , V _A2 , V _A3 , V _A4 applied to each image carrier cleaning roller 16 and the intermediate transfer member cleaning roller 46 are applied. The relationship with the bias voltage V _B is as shown in FIG. That is, a bias voltage is applied to each roller so that V _A1 <V _A4 , V _A2 <V _A4 , V _A3 <V _A4 , V _A4 <V _B.

In this way, the bias voltage V _B is set higher than any of the bias voltages V _A1 , V _A2 , V _A3 , V _A4 , and this is a residual liquid on the intermediate transfer member 40 that is removed by the intermediate transfer member cleaning roller 46. The toner particles of the developer have passed through the nip of the secondary transfer unit 60, and adhere more firmly than the toner particles of the liquid developer on any of the image carriers 10, and a higher bias voltage than that. This is because the liquid developer has to be removed by applying.

Among the bias voltages V _A1 , V _A2 , V _A3 , and V _A4 , the bias voltage V _A4 of the image carrier cleaning roller 16K is set to the highest. The reason for this setting is that the electrical characteristics of the YMC toner particles and the K toner particles are significantly different.

YMC toner particles use organic pigments, whereas K toner particle carbon black and iron oxide are used as pigments. Therefore, YMC toner particles and K toner particle carbon blacks are charged. There are many different electrical characteristics including electrical conductivity. Under the same conditions, the K toner particles are less charged than the YMC toner particles. Therefore, in order to obtain the same effect as the cleaning effect of the YMC image carrier cleaning roller with the image carrier cleaning roller 16K, it is necessary to set the bias voltage V _A4 higher than the bias voltages V _A1 , V _A2 and V _A3. There is.

  As described above, in the present exemplary embodiment, the bias voltage setting of the cleaning device is set according to the electrical characteristics such as the adhesion of toner particles in the liquid developer and the chargeability of the toner particles in the intermediate transfer body 40 and the image carrier 10. It is possible to perform appropriate cleaning according to the state of each cleaning object.

  Next, an example in which the bias voltage is changed according to the developing condition for the cleaning roller will be described. In an image forming apparatus using a liquid developer, the secondary transfer efficiency varies depending on the paper type of the recording medium. For this reason, it is necessary to change the amount of toner to be developed in accordance with the secondary transfer efficiency that varies depending on the paper type.

  For example, in the case of a paper type whose secondary transfer efficiency decreases, the toner amount of the toner image formed on the intermediate transfer body 40 is increased in advance, and the toner amount on the recording medium changes even if the secondary transfer efficiency is low. Do not. When the amount of toner supplied to the intermediate transfer member 40 is increased in this way, the rotation speed of the anilox roller 32 is increased and the thickness of the toner layer formed on the developing roller 20 is increased. By setting in this way, the amount of toner formed on the image carrier 10 can be increased, and as a result, the amount of toner formed on the intermediate transfer member 40 is increased.

  When the amount of toner formed on the image carrier 10 increases as described above, the cleaning bias voltage applied to the image carrier cleaning roller 16 for cleaning a large amount of toner particles from the image carrier 10 is small. Need to set higher than the time. At this time, since the amount of toner formed on the intermediate transfer intermediate transfer body 40 also increases, the bias voltage applied to the intermediate transfer body cleaning roller 46 of the intermediate transfer intermediate transfer body 40 is also set higher than when the toner amount is low. .

Even when the amount of toner increases in this way, the toner particles on the intermediate transfer body 40 adhere more firmly than the toner particles on the image carrier 10, so the toner particles on the intermediate transfer body 40 are cleaned. Therefore, the cleaning bias V _B applied to the intermediate transfer cleaning roller 46 is set higher than the cleaning bias V _A applied to the image carrier cleaning roller 16 of the image carrier 10.

From the viewpoint of control of the image forming apparatus, the secondary transfer efficiency varies depending on the recording medium, so that the amount of toner particles supplied to the image carrier 10 and the intermediate transfer body 40 is changed according to the recording medium to be printed. It becomes. In accordance with such a change, the bias voltage V _{A of the} image carrier cleaning roller 16 and the bias voltage V _B are controlled to be changed for the intermediate transfer member cleaning roller 46.

  The image forming apparatus is provided with a paper type determination sensor 5 for determining the paper type of the recording medium to be printed. Then, the rotation speed of the anilox roller 32 is changed according to the paper type determination result.

When the toner particle supply amount is changed depending on the paper type (that is, the development conditions in the development process are changed), the image forming apparatus cleans the bias voltage V _A of the image carrier cleaning roller 16 and the intermediate transfer body cleaning. The roller 46 is controlled to change the bias voltage V _B. Accordingly, the image carrier 10 and the intermediate transfer member 40 can be accurately cleaned according to the type of the recording medium.

  Next, the cleaning conditions by the cleaning blade will be described. FIG. 15 is a view for explaining the relationship between the contact angle of the image carrier cleaning blade and the contact angle of the intermediate transfer member cleaning blade.

The contact angle is defined as the angle between the contact plane of the image carrier 10 (or the intermediate transfer body 40 along the tension roller 42) on the line with which the cleaning blade contacts and the cleaning blade that contacts each other. (Note that, since FIG. 12 shows a cross section of each component, the contact angle can be regarded as an angle formed between the tangent to the image carrier 10 and the tension roller 42 and each cleaning blade.)
When the contact angle of the image carrier cleaning blade 18Y with respect to the image carrier 10Y is θ _A and the contact angle of the intermediate transfer member cleaning blade 49 with respect to the intermediate transfer member 40 is θ _B , θ _A > θ _B Set to be. This is because the intermediate transfer member 40 is a belt having a three-layer structure having relatively weak elasticity, whereas the surface layer of the image carrier 10 is made of amorphous silicon having a relatively high hardness. It is. Since the intermediate transfer body 40 having elasticity cannot be cleaned by increasing the contact angle, such setting of each contact angle is effective.

  As described above, in the present embodiment, the contact angle of the cleaning blade of the cleaning device is set according to the mechanical characteristics of the material of the intermediate transfer body 40 and the image carrier 10, and each cleaning object is set. Depending on the situation, it becomes possible to perform appropriate cleaning.

Next, the relationship between the contact pressure of the image carrier cleaning blade and the contact pressure of the intermediate transfer member cleaning blade will be described. In FIG. 15, arrows indicate the contact pressure of the image carrier cleaning blade 18 </ b> Y and the contact pressure of the intermediate transfer body cleaning blade 49. In this embodiment,
When the contact pressure of the image carrier cleaning blade 18Y with respect to the image carrier 10Y is P _A and the contact pressure of the intermediate transfer body cleaning blade 49 with respect to the intermediate transfer body 40 is P _B , P _A > P _B Set to be. The reason for this setting is to prevent the intermediate transfer body 40 from being destroyed by cleaning the intermediate transfer body 40 with elasticity by increasing the contact pressure as described above. . Even in such an embodiment, it is possible to appropriately perform cleaning according to the object to be cleaned.

  Next, control of contact and separation between the image carrier cleaning blade and the intermediate transfer member cleaning blade will be described.

  In the image forming apparatus of the present invention, when printing is interrupted due to a paper jam or the like and a large amount of toner image remains on the image carrier 10Y and is to be cleaned, the image carrier cleaning blade 18 is removed from the image carrier 10. A process for separating them is executed. In addition, when a predetermined amount of carrier is used on the intermediate transfer body 40, this cannot be performed when the intermediate transfer body cleaning blade 49 is in contact with the intermediate transfer body 40. Thus, the intermediate transfer body cleaning blade 49 is separated from the intermediate transfer body 40.

As described above, control is performed such that the image carrier cleaning blade 18 is separated from the image carrier 10 and the intermediate transfer member cleaning blade 49 is separated from the intermediate transfer member 40 before starting a predetermined operation in the image forming apparatus. Thereafter, when the image forming apparatus also performs a normal printing operation, the image carrier cleaning blade 18 and the image carrier 10 are brought into contact with each other, and the intermediate transfer member cleaning blade 49 is connected to the intermediate transfer member 40. Each contact / separation mechanism is controlled so as to make contact, and at this time, the relationship between the contact angles is controlled so that θ _A > θ _B. Such control makes it possible to perform appropriate cleaning according to the state of each cleaning object.

Similarly, when control is performed so that the image carrier cleaning blade 18 and the image carrier 10 are brought into contact with each other and the intermediate transfer member cleaning blade 49 is brought into contact with the intermediate transfer member 40, the relationship between the contact pressures is P. It is controlled such that _a> P _B. Such control makes it possible to perform appropriate cleaning according to the state of each cleaning object.

  Note that although various embodiments have been described in this specification, embodiments configured by appropriately combining the configurations of the respective embodiments are also included in the scope of the present invention.

1 is a diagram illustrating main components constituting an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which showed the main components of the image formation part and the cleaning apparatus. FIG. 6 is a diagram for explaining the contact and separation of the intermediate transfer member cleaning blade in the present invention. FIG. 3 is a diagram illustrating a structure of an intermediate transfer member in the present invention. It is a figure which shows the example of arrangement | positioning of the cleaning apparatus in this invention. It is a figure which shows the state at the time of a stop of the developing device of this invention, and the state at the time of operation | movement. It is a figure which shows the flow of the liquid developer in a developing device. It is a perspective view of the aniloc roller used for this invention. It is a figure which shows the structure of the cleaning apparatus in a secondary transfer unit. FIG. 3 is a diagram illustrating a configuration of an intermediate transfer member cleaning device. FIG. 6 is a diagram illustrating a relationship between an image carrier cleaning roller applied bias voltage and an intermediate transfer body cleaning roller applied bias voltage. FIG. 6 is a diagram illustrating main components constituting an image forming apparatus according to another embodiment of the present invention. FIG. 6 is a diagram illustrating a relationship between an image carrier cleaning roller applied bias voltage and an intermediate transfer body cleaning roller applied bias voltage. FIG. 6 is a diagram illustrating a relationship between an image carrier cleaning roller applied bias voltage and an intermediate transfer body cleaning roller applied bias voltage. FIG. 6 is a diagram illustrating a relationship between an abutting angle of an image carrier cleaning blade and an abutting angle of an intermediate transfer member cleaning blade.

Explanation of symbols

5 ... Paper type determination sensor, 6 ... Light emitting element, 7 ... Light receiving element, 10Y, 10M, 10C, 10K ... Image carrier, 11Y, 11M, 11C, 11K ... Corona charger , 12Y, 12M, 12C, 12K ... exposure unit, 13Y, 13Y '... image carrier squeeze roller, 14Y, 14Y' ... image carrier squeeze roller cleaning blade, 16Y ... image carrier cleaning Roller, 17Y: Image carrier cleaning roller cleaning blade, 18Y: Image carrier cleaning blade, 20Y, 20M, 20C, 20K ... Developing roller, 21Y ... Developing roller cleaning blade, 22Y ... Compaction corona generator, 24Y ... carrier amount adjustment roller, 25Y ... carrier amount adjustment air knife, 0Y, 30M, 30C, 30K ... developer, 31Y, 31M, 31C, 31K ... developer container, 32Y, 32M, 32C, 32K ... anilox roller, 31Y, 31M, 31C, 31K ... Developer container, 33Y ... regulating blade, 34Y ... auger (supply roller), 40 ... intermediate transfer member, 41 ... belt drive roller, 42 ... tension roller, 45 ... developer Collection department,
46... Intermediate transfer body cleaning roller, 47... Intermediate transfer body cleaning roller cleaning blade, 49... Intermediate transfer body cleaning blade, 50 Y, 50 M, 50 C, 50 K... Primary transfer portion, 51 Y, 51 M, 51 C 51K ... primary transfer backup roller, 52, 53 ... tension roller, 60 ... secondary transfer unit, 61 ... secondary transfer roller, 62 ... secondary transfer roller cleaning blade, 70Y, 71Y, 72Y, 73Y, 74, 76Y (cleaning) blade holding member, 75Y ... regulating blade holding member, 77, 78 ... cleaning blade holding member,
80Y... Image carrier recovery and storage section, 81Y... Recovery screw, 85... Secondary transfer unit recovery storage section, 86... Recovery screw, 87. ..Recovery screw, 310Y... Supply storage unit, 320Y... Recovery storage unit, 321Y... Recovery screw, 330Y... Partitioning unit, 360Y. Developer supply port, 370Y ... Liquid developer supply tube, 371Y ... Liquid developer recovery tube

Claims (8)

An image carrier for carrying a developed image by a liquid developer containing a carrier and toner particles;
An image carrier cleaning roller to which a bias voltage V _A is applied and in contact with the image carrier;
An intermediate transfer member to which a developed image is transferred from the image carrier;
An intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member;
Between the bias voltage V _A and the bias voltage V _B ,
V _A <V _B
An image forming apparatus having the following relationship: A first image carrier for carrying a developed image by a liquid developer containing a carrier and first color toner particles;
A second image carrier for carrying a developed image by a liquid developer containing a carrier and second color toner particles;
A third image carrier for carrying a developed image by a liquid developer containing a carrier and third color toner particles;
A fourth image carrier for carrying a developed image by a liquid developer containing a carrier and fourth color toner particles;
A first image carrier cleaning roller to which a bias voltage V _A1 is applied and in contact with the first image carrier;
A second image carrier cleaning roller to which a bias voltage V _A2 is applied and in contact with the first image carrier;
A third image carrier cleaning roller to which a bias voltage V _A3 is applied and in contact with the first image carrier;
A fourth image carrier cleaning roller to which a bias voltage V _A4 is applied and in contact with the first image carrier;
An intermediate transfer member to which a developed image of each color is transferred from the first image carrier, the second image carrier, the third image carrier, and the fourth image carrier;
An intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member;
The relationship of V _A1 <V _B is established between the bias voltage V _A1 and the bias voltage V _B.
Between the bias voltage V _A2 and the bias voltage V _B , a relationship of V _A2 <V _B is established.
Between the bias voltage V _A3 and the bias voltage V _B , a relationship of V _A3 <V _B is established.
An image forming apparatus having a relationship of V _A4 <V _B between the bias voltage V _A4 and the bias voltage V _B. A first image carrier for carrying a developed image by a liquid developer containing a carrier and first color toner particles;
A second image carrier for carrying a developed image by a liquid developer containing a carrier and second color toner particles;
A third image carrier for carrying a developed image by a liquid developer containing a carrier and third color toner particles;
A fourth image carrier for carrying a developed image by a liquid developer containing a carrier and fourth color toner particles;
A first image carrier cleaning roller to which a bias voltage V _A1 is applied and in contact with the first image carrier;
A second image carrier cleaning roller to which a bias voltage V _A2 is applied and in contact with the first image carrier;
A third image carrier cleaning roller to which a bias voltage V _A3 is applied and in contact with the first image carrier;
A fourth image carrier cleaning roller to which a bias voltage V _A4 is applied and in contact with the first image carrier;
An intermediate transfer member to which a developed image of each color is transferred from the first image carrier, the second image carrier, the third image carrier, and the fourth image carrier;
An intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member;
Between the bias voltage V _{A1, the} bias voltage V _A2 , the bias voltage V _A3 , the bias voltage V _A4, and the bias voltage V _B ,
V _A1 <V _A4 , V _A2 <V _A4 , V _A3 <V _A4 , V _A4 <V _B
An image forming apparatus having the following relationship: An image carrier cleaning blade in contact with the image carrier;
The image forming apparatus according to claim 1, further comprising an intermediate transfer member cleaning blade that contacts the intermediate transfer member. The image forming apparatus according to claim 1, wherein the intermediate transfer member includes an elastic layer. 6. The image according to claim 4, wherein an angle at which the image carrier cleaning blade comes into contact with the image carrier is larger than an angle at which the intermediate transfer body cleaning blade comes into contact with the intermediate transfer body. Forming equipment. An image carrier for carrying a developed image by a liquid developer containing a carrier and toner particles;
An image carrier cleaning roller to which a bias voltage V _A is applied and in contact with the image carrier;
An intermediate transfer member to which a developed image is transferred from the image carrier;
An intermediate transfer member cleaning roller to which a bias voltage V _B is applied and in contact with the intermediate transfer member;
When the bias voltage V _A has a relationship of V _A <V _B between the bias voltage V _B and the development conditions are different, the bias voltage V _A applied to the image carrier cleaning roller; A control method for an image forming apparatus, wherein the bias voltage V _B applied to the intermediate transfer member cleaning roller is changed. 8. The method of controlling an image forming apparatus according to claim 7, wherein the different development conditions are different types of recording media to be developed.

Images