JP2009157327A - Image forming device and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device accurately obtaining positional information of a resist mark without decreasing resist mark detection accuracy by an optical sensor. <P>SOLUTION: This image forming device has a plurality of image carriers 10 which carry an image developed by a liquid developing agent of a different color containing a carrier and toner particles for each color; an intermediate transfer body 40 on which the developed image is transferred from the plurality of image carriers 10 and which moves in a predetermined direction; and an optical sensor 90 which detects the developed image transferred to a predetermined place on the intermediate transfer body 40. This control method includes a correction mode to transfer resist marks to the predetermined place on the intermediate transfer body 40 with the plurality of image carriers 10, detect the resist marks by the optical sensor 90, compute color shift quantity between different colors, and correct the computed color shift quantity. In the color shift correction mode, the carrier removal quantity on the intermediate transfer body 40 is increased. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus for superimposing a plurality of color liquid developers to form a color image, and a control method for the image forming apparatus. In particular, the present invention relates to an intermediate transfer of a developed image formed on an image carrier. An image forming apparatus and a control method for the image forming apparatus that perform a transfer process for transferring onto a transfer medium such as a belt for each color liquid developer to form a color image on the transfer medium.

  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.

  As this type of image forming apparatus, for example, an apparatus described in Japanese Patent Application Laid-Open No. 2006-126258 is known. In this image forming apparatus, an image forming station in which a charging unit, an image writing unit, and a developing unit are arranged around a latent image carrier such as a photosensitive drum is provided for each color along a transfer medium such as a transfer belt. Yes. A toner image formed at each image forming station is superimposed on a transfer medium to form a color image.

  Incidentally, color misregistration is one of the serious problems in an image forming apparatus having a plurality of image forming stations. This occurs when the transfer positions of the toner images formed at different image forming stations onto the transfer medium are shifted from each other, and appear as a change in color tone. In order to solve this problem, a reference pattern image (hereinafter referred to as “registration mark”) for detecting color misregistration is formed on a transfer medium in advance, and each registration mark is detected by an optical sensor. Registration mark position information is obtained, and each toner image is aligned (color misregistration correction processing, position misalignment correction processing) based on the position information.

In Patent Document 1, the color misregistration correction processing of the image forming apparatus is described in relation to FIG. In the gazette of Patent Document 1, as shown in FIG. 12, for example, registration marks YRM, MRM, CRM, and KRM are printed on the intermediate transfer belt 41 in the order of yellow, magenta, cyan, and black immediately after the apparatus is turned on. By performing an image forming operation, a toner image is formed. At this time, as image formation timing, control is performed so that registration marks YRM, MRM, CRM, and KRM are formed on the reference position S0. However, due to the assembly error of the apparatus, as shown in FIG. 12, in the scanning direction X 1 of the light beam, errors Sm, Sc, Sk are generated from the reference position S0 to form the respective registration marks MRM, CRM, KRM. May be. The errors Sm, Sc, Sk are measured by a sensor such as a CCD camera, and the image formation timing (scanning timing of the light beam 21) is changed so that the image position is shifted by the errors Sm, Sc, Sk. The error can be corrected and eliminated.
JP 2006-126258 A

  In a wet-type image forming apparatus using a liquid developer in which toner is dispersed in a high-viscosity, non-volatile carrier liquid, the carrier liquid on the intermediate transfer belt is a recording medium such as paper during the image forming process. This is essential for secondary transfer. However, since the toner image containing the carrier liquid on the intermediate transfer belt has high specularity, it causes a false detection when the light detection sensor detects the registration mark. That is, during the color misregistration correction process in the image forming apparatus described in Patent Document 1, there is a problem that the accuracy of the registration mark detection result by a sensor such as a CCD camera may be reduced. However, there is a problem in that the position information of the registration mark cannot be obtained accurately and color misregistration correction may not be performed with accuracy.

  SUMMARY An advantage of some aspects of the invention is that an image forming apparatus according to the present invention has a plurality of image carriers that carry developed images of liquid developers of different colors including carriers and toner particles for each color. An intermediate transfer body that transfers a developed image from the plurality of image carriers and moves in a predetermined direction, and an optical sensor that detects the developed image transferred to a predetermined position on the intermediate transfer body. Then, the registration marks are transferred to the predetermined locations of the intermediate transfer body by the plurality of image carriers, the registration marks are detected by the optical sensor, the amount of color misregistration between different colors is calculated, and the calculated color misregistration is calculated. A color misregistration correction mode for correcting the amount is provided, and when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer member is increased.

  In addition, the image forming apparatus according to the present invention includes an intermediate transfer member squeeze roller disposed downstream of the plurality of image carriers, and when the color misregistration correction mode is executed, the periphery of the intermediate transfer member squeeze roller is The carrier removal amount on the intermediate transfer member is increased by setting the direction rotation speed faster than the moving speed of the intermediate transfer member.

  In addition, when executing the color misregistration correction mode, the image forming apparatus according to the present invention causes the intermediate transfer member squeeze roller to rotate in the nip portion so that the rotation direction of the intermediate transfer member squeeze roller faces the intermediate transfer member. It is characterized by increasing the amount of carrier removal on the body.

  The image forming apparatus according to the present invention further includes a plurality of intermediate transfer member squeeze rollers disposed downstream of each of the plurality of image carriers, and the circumferential rotation speed of the plurality of intermediate transfer member squeeze rollers is set. The carrier removal amount on the intermediate transfer member is increased by setting it faster than the moving speed of the intermediate transfer member.

  In the image forming apparatus according to the present invention, the plurality of image carriers are provided with an image carrier squeeze roller that is in contact with the upstream side of the nip portion with the intermediate transfer member. At the time of execution, the carrier removal amount on the intermediate transfer member is increased by setting the circumferential rotational speed of the image carrier squeeze roller faster than the circumferential rotational speed of the image carrier.

  In the image forming apparatus according to the present invention, an image carrier squeeze roller is disposed on the plurality of image carriers in an upstream side of a nip portion with the intermediate transfer member so as to be able to come into contact with the image carrier. When executing the correction mode, the image carrier squeeze roller is brought into contact with the image carrier to increase the carrier removal amount on the intermediate transfer member.

  The image forming apparatus according to the present invention further includes a registration mark intermediate transfer body squeeze roller that is disposed downstream of the plurality of image carriers and abuts in the vicinity of a predetermined position of the intermediate transfer body to which the registration mark is transferred. When the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer member is increased by the registration mark intermediate transfer member squeeze roller.

  Also, the control method of the image forming apparatus according to the present invention includes a plurality of image carriers that carry developed images of liquid developers of different colors including carriers and toner particles for each color, and the plurality of image carriers. A control method for an image forming apparatus, comprising: an intermediate transfer body that transfers a developed image from a body and moves in a predetermined direction; and an optical sensor that detects the developed image transferred to a predetermined position on the intermediate transfer body. The registration marks are transferred to the predetermined locations of the intermediate transfer body by the plurality of image carriers, the registration marks are detected by the optical sensor, and the amount of color misregistration between different colors is calculated. A color misregistration correction mode for correcting the amount is provided, and when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer member is increased.

  According to the present invention, when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer belt is controlled to be increased as compared with the normal printing operation. Since the registration mark position information can be accurately obtained without deteriorating the detection accuracy, color misregistration can be corrected with high accuracy.

  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 first 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.

  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 between the driving roller 41 and the tension roller 42, and is contacted with the image carriers 10Y, 10M, 10C, and 10K by the primary transfer portions 50Y, 50M, 50C, and 50K. It is rotationally driven by the driving roller 41 while in contact. 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 90 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 and fixed on the recording medium such as paper. Let

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

  Next, the image forming unit and the developing 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 developing 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. A carrier squeeze roller 13Y is disposed.

  Reference numeral 17Y denotes an image carrier cleaning roller cleaning blade for cleaning the image carrier cleaning roller 16Y. The image carrier squeeze roller 13Y is provided with a cleaning device including an image carrier squeeze roller cleaning blade 14Y as an additional component.

  Reference numeral 70Y denotes a first image carrier developer collecting portion for receiving the liquid developer dropped from the image carrier squeeze roller cleaning blade 14Y. Reference numeral 73Y denotes an image carrier cleaning roller cleaning blade 17Y and an image carrier cleaning blade 18Y. 3 is a third image carrier developer collecting portion for receiving the liquid developer dripped from the first image carrier. A pipe for flowing the liquid developer received from the blade is provided below the first image carrier developer collecting unit 70Y, and a liquid developer received from the blade is provided below the third image carrier developer collecting unit 73Y. A pipe for flowing the agent is connected.

  A developing roller cleaning blade 21Y, an anilox roller 32Y, and a toner compression corona generator 22Y are arranged 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.

  Reference numeral 72Y denotes a developing roller developer collecting unit for receiving the liquid developer dripped from the developing roller cleaning blade 21Y, and a pipe for flowing the liquid developer received from the blade is provided below the developing roller developer collecting unit 72Y. It is connected. Further, a liquid developer supply roller 34Y is 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.

  FIG. 3 is a view showing an intermediate transfer member squeeze device of the image forming apparatus according to the first embodiment of the present invention. Such an intermediate transfer member squeeze device is for squeezing the intermediate transfer member 40 immediately downstream of the transfer nip of the image carrier 10K. In the present embodiment, an intermediate transfer member squeeze device 52K including an intermediate transfer member squeeze roller 53K, a backup roller 54K, and an intermediate transfer member squeeze roller cleaning blade 55K is disposed on the downstream side in the moving direction of the intermediate transfer member 40 of the developing device 30K. ing.

  Reference numeral 84K denotes a first intermediate transfer member developer collecting portion for receiving the liquid developer dripped from the intermediate transfer member squeeze roller cleaning blade 55K, and the lower portion of the first intermediate transfer member developer collecting portion 84K is received from the blade. A pipe for flowing the liquid developer is connected.

  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 photosensitive layer of the image carrier 10Y is composed of an organic image carrier or 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 toner compression 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 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, a supply roller 34Y for supplying the anilox roller 32Y while stirring and conveying the liquid developer, a toner compression corona generator 22Y for bringing the liquid developer carried on the developing roller 20Y into a compacted state, and development A developing roller cleaning blade 21Y for cleaning the roller 20Y is provided.

  The liquid developer accommodated in the developer container 31Y is a low concentration (about 1 to 2 wt%) and low viscosity with Isopar (trademark: exon) as a carrier, which is generally used, and is volatile at room temperature. It is not a volatile liquid developer having a property, but a non-volatile liquid developer having a high concentration and a high viscosity and having a non-volatile property 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 anilox roller 32Y functions as an application roller that supplies and applies a liquid developer to the developing roller 20Y. 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 supply roller 34Y rotates clockwise to supply the liquid developer to the aniloc roller 32Y, and the aniloc roller 32Y rotates counterclockwise to develop the developing roller 20Y. A liquid developer is applied to the substrate.

  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 toner compression corona generator 22Y is an electric field applying means for increasing the charging bias on the surface of the developing roller 20Y. The liquid developer conveyed by the developing roller 20Y is fed by the toner compression corona generator 22Y as shown in FIG. An electric field is applied from the toner compression corona generator 22Y side toward the developing roller 20Y at the toner compression site.

  The electric field applying means for compressing the toner may use a compaction roller or the like 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 compressed by toner carried on the developing roller 20Y corresponds 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. Developed. The developer remaining after development is scraped off and removed by the developing roller cleaning blade 21Y, and dropped into the developing roller developer collecting unit 72Y 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. The image carrier squeeze roller 13Y is composed of an elastic roller member that is covered with an elastic body and is slidably contacted with the image carrier 10Y. The image carrier squeeze roller 13Y is pressed and slidably contacted with the image carrier squeeze roller 13Y. The image carrier squeeze roller cleaning blade 14Y to be cleaned has a function of collecting excess carrier and originally unnecessary fog toner from the developer developed on the image carrier 10Y, and increasing the toner particle ratio in the visible image. Have.

  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 cleaning device disposed on the downstream side of the primary transfer is disposed on the downstream side of the primary transfer portion 50Y so as to face the image carrier 10Y, and the surplus on the image carrier 10Y is formed before the electrostatic latent image is formed. As shown in FIG. 2, an image carrier cleaning roller 16Y comprising an elastic roller member whose surface is covered with an elastic body and rotates in sliding contact with the image carrier 10Y, as shown in FIG. It comprises an image carrier cleaning roller cleaning blade 17Y that presses and slides on the carrier cleaning roller 16Y to clean the surface, and has a function of collecting excess carrier and unnecessary toner that has not been transferred. The image carrier cleaning roller 16Y has a structure in which a rubber layer is provided on the surface layer of the metal roller base material, and a bias voltage is applied so as to attract toner particles from the image carrier 10Y. The image carrier cleaning roller 16Y is provided mainly for the purpose of cleaning the toner particle component in the remaining liquid developer.

  An image carrier cleaning blade 18Y configured to completely clean the surface state of the image carrier 10Y before a new electrostatic latent image is formed is disposed downstream of the image carrier cleaning roller 16Y. The The image carrier cleaning blade 18Y is provided mainly for the purpose of cleaning the carrier component in the remaining liquid developer.

  The intermediate transfer member squeeze device 52K is disposed on the downstream side of the primary transfer portion 50K, and performs a process of removing excess carrier liquid from the intermediate transfer member 40 and increasing the toner particle ratio in the visible image.

  The intermediate transfer member squeeze device 52K, like the image carrier squeeze device, has an intermediate transfer member squeeze roller 53K composed of an elastic roller member that covers an elastic member and rotates in contact with the intermediate transfer member 40, and the intermediate transfer member 40. The intermediate transfer member squeeze roller 53K is placed opposite to the backup roller 54K, and the intermediate transfer member squeeze roller 53K is pressed and slidably contacted with the cleaning blade 55K to clean the surface. It has a function of collecting excess carrier and originally unnecessary fog toner from the agent.

  Next, the flow of the liquid developer in the image forming apparatus of the present invention will be described with reference to FIGS. A secondary transfer roller 61 is disposed opposite to the belt driving roller 41 with the intermediate transfer member 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 is disposed.

  Reference numeral 63 denotes a secondary transfer roller developer collecting unit for receiving the liquid developer dripped from the secondary transfer roller cleaning blade 62. A liquid developer received from the blade is disposed below the secondary transfer roller developer collecting unit 63. Piping to flow is connected. This pipe leads to the first waste liquid tank 440. Since the liquid developer scraped off by the secondary transfer roller cleaning blade 62 is a liquid developer mixed with toner, the liquid developer recovered by the secondary transfer roller developer recovery unit 63 passes through the pipe to the first waste liquid tank 440. Discarded.

  Reference numeral 47 denotes a second intermediate transfer member developer collecting unit for receiving the liquid developer dripped from the intermediate transfer member cleaning blade 46. The lower intermediate transfer member developer collecting unit 47 receives the liquid developer from the blade. A pipe for flowing the liquid developer is connected. This pipe communicates with the second waste liquid tank 441. Since the liquid developer scraped off by the intermediate transfer member cleaning blade 46 is a liquid developer mixed with toner, the liquid developer recovered by the second intermediate transfer member developer recovery unit 47 passes through the pipe to the second waste liquid tank 441. Discarded.

  In FIG. 1, 400Y, 400M, 400C and 400K are stirring tanks, 401Y, 401M, 401C and 401K are developer supply tanks, 402Y, 402M, 402C and 402K are buffer tanks, 410 is a carrier tank, 450Y, 450M and 450C, 450K is the first pump, 451Y, 451M, 451C and 451K are the second pump, 452Y, 452M, 452C and 452K are the third pump, and 453Y, 453M, 453C and 453K are the fourth pump. The lines between the container, the recovery unit, the tank, and the pump in FIG. 1 schematically show the piping.

  The stirring tanks 400Y, 400M, 400C, and 400K are tanks for adjusting a liquid developer having a toner solid content concentration of about 20% to be supplied to the developer containers 31Y, 31M, 31C, and 31K.

  The developer supply tanks 401Y, 401M, 401C, and 401K are tanks that store high-concentration toner having a toner solid content concentration of about 20% or more, and the carrier tank 410 is a tank that stores a carrier stock solution. The tanks 400Y, 400M, 400C, and 400K are piped through fourth pumps 453Y, 453M, 453C, and 453K.

  The agitation tanks 400Y, 400M, 400C, and 400K receive high-density toner from the high-density toner tank developer supply tanks 401Y, 401M, 401C, and 401K. For this purpose, the second pumps 451Y, 451M, 451C, 451K are driven.

  The stirring tanks 400Y, 400M, 400C and 400K are supplied with the carrier stock solution from the carrier tank 420Y by driving the fourth pumps 453Y, 453M, 453C and 453K.

  The stirring tanks 400Y, 400M, 400C, and 400K are provided with toner concentration detection means such as an optical sensor (not shown). The toner density detection means detects the density, and the stirring tanks 400Y, 400M, 400C, and 400K On / off control of each pump is executed by a control unit (not shown) so that the concentration of the liquid developer becomes appropriate. Further, by driving a stirring unit (not shown) provided in the stirring tanks 400Y, 400M, 400C, and 400K, the inside of the stirring tank is uniformly stirred.

  During operation of the apparatus, an appropriate amount of liquid developer is supplied to the developer containers 31Y, 31M, 31C, and 31K from the constant stirring tanks 400Y, 400M, 400C, and 400K by the first pumps 450Y, 450M, 450C, and 450K. It is like that.

  The first image carrier developer recovery 70Y, 70M, 70C, 70K and the developing roller developer recovery units 72Y, 72M, 72C, 72K are provided by piping, and the recovered liquid developer is contained in the stirring tanks 400Y, 400M, 400C, 400K. The liquid developer is reused.

  The third image carrier developer collections 73Y, 73M, 73C, and 73K are once stored in the buffer tanks 402Y, 402M, 402C, and 402K by piping. From these buffer tanks 402Y, 402M, 402C, 402K, the liquid developer is sent to the stirring tanks 400Y, 400M, 400C, 400K by the operation of the second pumps 451Y, 451M, 451C, 451K. Here, the second pumps 451Y, 451M, 451C, 451K, etc. are used because the solid concentration of the liquid developer recovered by the third image carrier developer recovery 73Y, 73M, 73C, 73K is high. Because.

  The liquid developer collected by the developer collecting unit in each color unit is the one before color superposition, and since no color mixing occurs, it is recycled by collection. On the other hand, since the flow of the liquid developer collected by the first intermediate transfer member developer collecting unit 84K is a liquid developer in which toner is mixed, it is discarded to the second waste liquid tank 441 through a pipe.

  Next, the color misregistration correction mode in the present invention will be described. As in the present invention, there is a problem of color misregistration in an image forming apparatus that forms images with the four color developing devices 30Y, 30M, 30C, and 30K. That is, when toner images formed by different developing devices 30Y, 30M, 30C, and 30K are transferred to the intermediate transfer medium 40, the transfer positions are shifted from each other, and this shift is a change in color tone on the recording medium. There is a problem of appearing.

  In order to solve this problem, the image forming apparatus forms a reference pattern image (hereinafter referred to as a “registration mark”) for detecting color misregistration on the intermediate transfer medium 40 in advance, and sets each registration mark. A color misregistration correction mode is provided in which the position information of the registration mark is obtained by detection by the optical sensor 90, and each toner image is aligned (color misregistration correction processing, position misalignment correction processing) based on the position information.

  As shown in FIG. 1, the optical sensor 90 for detecting the registration mark is provided in the front stage of the transfer nip in the secondary transfer unit 60. As such an optical sensor 90, a well-known sensor such as a pair of light-emitting elements and light-receiving elements or a CCD camera can be used.

  In the color misregistration correction mode of the image forming apparatus, as shown in FIG. 12, for example, immediately after the apparatus is turned on, the registration marks YRM, MRM, The CRM and KRM are formed as toner images by executing an image forming process.

  The registration marks formed as described above are detected by the optical sensor 90, and the amount of color misregistration between different colors is calculated by a calculation means (not shown). In the color misregistration correction mode, the image forming apparatus is controlled so as to correct the color misregistration amount calculated by the calculation means by a known method.

  By the way, the toner image containing the carrier liquid on the intermediate transfer body 40 has high mirror surface properties, and thus causes a false detection when the optical sensor 90 detects the registration mark. At the time of color misregistration correction processing in a wet type image forming apparatus, there is a possibility that the accuracy of the registration mark detection result by the optical sensor 90 may be reduced. There was a problem that correction may not be possible.

  In order to cope with such a problem, in the present embodiment, when executing the color misregistration correction mode, the control for increasing the carrier removal amount on the intermediate transfer body 40 as compared with the case of the normal printing operation. I do.

  In the image forming apparatus according to the first embodiment of the present invention, when the color misregistration correction mode is executed, the intermediate transfer member squeeze device removes more carriers than in the normal printing operation.

  In the intermediate transfer body squeeze device, during a normal printing operation, the intermediate transfer body squeeze roller 53K is controlled to rotate at the same circumferential rotational speed as the moving speed of the intermediate transfer body 40. On the other hand, when the color misregistration correction mode is executed, the intermediate transfer member squeeze roller 53K is controlled to rotate at a circumferential rotational speed faster than the moving speed of the intermediate transfer member 40, and the intermediate transfer member squeeze roller 53K. Thus, the carrier removal amount on the intermediate transfer body 40 is increased as compared with the case of the normal printing operation.

  3A shows the state of the intermediate transfer member squeeze device during a normal printing operation, and FIG. 3B shows the state of the intermediate transfer member squeeze device when the color misregistration correction mode is executed. Yes. As shown in FIG. 3, during a normal printing operation, the intermediate transfer body squeeze roller 53K is controlled to rotate in the rotational direction that is the same as the moving direction of the intermediate transfer body 40 and the nip portion. When the color misregistration correction mode is executed, the intermediate transfer member squeeze roller 53K is controlled to rotate in the rotation direction opposite to the moving direction of the intermediate transfer member 40 at the nip portion, and the intermediate transfer member squeeze roller 53K is used. The carrier removal amount on the intermediate transfer body 40 may be increased as compared with a normal printing operation.

  Further, the intermediate transfer body squeeze roller 53K is controlled to rotate at a circumferential rotational speed faster than the movement speed of the intermediate transfer body 40, and the intermediate transfer body squeeze roller 53K is moved in the nip portion in accordance with the moving direction of the intermediate transfer body 40. You may control to rotate in the rotation direction used as a reverse direction.

  In the embodiment shown in FIG. 3B, since the intermediate transfer member squeeze roller 53K is rotated in the direction opposite to the moving direction of the intermediate transfer member 40, the registration mark formed on the intermediate transfer member 40 may be disturbed. When the color misregistration correction mode is executed, it is preferable to apply a bias voltage for pressing the toner in the registration mark in the direction from the intermediate transfer member squeeze roller 53K to the intermediate transfer member 40.

  As described above, according to the first embodiment of the present invention, when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer body 40 is increased as compared with the case of a normal printing operation. Therefore, the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy by the optical sensor, so that color misregistration can be corrected with high accuracy.

  Next, a second embodiment of the present invention will be described. FIG. 4 is a diagram showing main components constituting the image forming apparatus according to the second embodiment of the present invention, and FIG. 5 is a main configuration of the image forming unit and the developing device in the second embodiment of the present invention. It is sectional drawing which showed the element.

  In the first embodiment, the intermediate transfer member squeeze device is provided only immediately downstream of the transfer nip of the image carrier 10K. However, in the second embodiment, the intermediate transfer member squeeze device is an image carrier 10Y, 10M, 10C and 10K are provided immediately downstream of the transfer nips.

  With reference to FIG. 5, an intermediate transfer member squeeze device immediately downstream of each color transfer nip will be described by taking yellow as an example. Since the other colors have the same configuration, only the yellow color will be described here as a representative.

  The intermediate transfer body squeeze device of the second embodiment is for squeezing the intermediate transfer body 40 immediately downstream of the transfer nip of the image carrier 10Y. In the present embodiment, an intermediate transfer member squeeze device 52Y including an intermediate transfer member squeeze roller 53Y, a backup roller 54Y, and an intermediate transfer member squeeze roller cleaning blade 55Y is disposed on the downstream side in the moving direction of the intermediate transfer member 40 of the developing device 30Y. ing.

  Reference numeral 84Y denotes a first intermediate transfer member developer collecting portion for receiving the liquid developer dripped from the intermediate transfer member squeeze roller cleaning blade 55Y. The lower portion of the first intermediate transfer member developer collecting portion 84Y is received from the blade. A pipe for flowing the liquid developer is connected. Further, since the liquid developer recovered by the first intermediate transfer member developer recovery unit 84Y is a liquid developer causing color mixing, it is discarded into the second waste liquid tank 441 through a pipe and is not reused.

  Also in the second embodiment, when the color misregistration correction mode is executed, control is performed to increase the carrier removal amount on the intermediate transfer body 40 as compared with a normal printing operation.

  In the image forming apparatus according to the second embodiment of the present invention, when the color misregistration correction mode is executed, the intermediate transfer body squeeze devices 52Y, 52M, 52C, and 52K after the primary transfer nip of each color are used in a normal manner. More carriers are removed than during printing operations.

  During a normal printing operation, the intermediate transfer body squeeze devices 52Y, 52M, 52C, and 52K use the intermediate transfer body squeeze rollers 53Y, 53M, 53C, and 53K at the same rotational speed as the intermediate transfer body 40. Control to rotate. On the other hand, when executing the color misregistration correction mode, the intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K are controlled to rotate at a circumferential rotational speed that is faster than the moving speed of the intermediate transfer member 40. The intermediate transfer body squeeze rollers 53Y, 53M, 53C, and 53K increase the carrier removal amount on the intermediate transfer body 40 as compared with the case of a normal printing operation.

  Although not particularly shown, during normal printing operation, the intermediate transfer member squeeze roller 53K is controlled to rotate in the rotational direction that is the same as the moving direction of the intermediate transfer member 40 and the nip portion. When the color misregistration correction mode is executed, the intermediate transfer body squeeze rollers 53Y, 53M, 53C, and 53K are controlled to rotate in the rotation direction opposite to the moving direction of the intermediate transfer body 40 at the nip portion. The intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K may increase the amount of carrier removal on the intermediate transfer member 40 as compared with a normal printing operation.

  Further, the intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K are controlled to rotate at a circumferential rotational speed faster than the moving speed of the intermediate transfer member 40, and the intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K are controlled. May be controlled to rotate in a rotation direction opposite to the moving direction of the intermediate transfer body 40 at the nip portion.

  Further, since the intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K are rotated in the direction opposite to the moving direction of the intermediate transfer member 40, there is a possibility that the registration mark formed on the intermediate transfer member 40 may be disturbed. When the mode is executed, it is preferable to apply a bias voltage for pressing the toner in the registration mark from the intermediate transfer member squeeze rollers 53Y, 53M, 53C, and 53K toward the intermediate transfer member 40.

  As described above, according to the second embodiment of the present invention, when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer body 40 is increased as compared with the normal printing operation. Therefore, the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy by the optical sensor, so that color misregistration can be corrected with high accuracy.

  Next, a third embodiment of the present invention will be described. In the third embodiment, the same configuration as that of the first embodiment and the second embodiment can be used. Also in the third embodiment, when the color misregistration correction mode is executed, control is performed to increase the carrier removal amount on the intermediate transfer body 40 as compared with the case of a normal printing operation. For this reason, in the third embodiment, when the color misregistration correction mode is executed, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K before the primary transfer nip of each color are used during normal printing operation. Many carriers are removed, so that the amount of carrier removal on the intermediate transfer body 40 is increased.

  During normal printing operation, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K are controlled to rotate at the same circumferential rotational speed as the circumferential rotational speeds of the image carriers 10Y, 10M, 10C, and 10K. . On the other hand, when the color misregistration correction mode is executed, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K are faster in the circumferential rotation speed than the circumferential rotation speeds of the image carriers 10Y, 10M, 10C, and 10K. And the carrier removal amount in the image carriers 10Y, 10M, 10C, and 10K is increased, so that the carrier removal amount on the intermediate transfer member 40 is set as compared with that in the normal printing operation. Try to increase.

  The rotation speed [rpm] of the image carrier squeeze rollers 13Y, 13M, 13C, and 13K during the normal printing operation is set to 235.34, and the image carrier squeeze rollers 13Y and 13M when the color misregistration correction mode is executed. , 13C, and 13K are set to 238.43.

  Although not particularly shown, during normal printing operation, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K are in the same direction as the rotation direction of the image carriers 10Y, 10M, 10C, and 10K in the nip portion. In contrast to controlling to rotate in the rotational direction, when executing the color misregistration correction mode, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K are moved to the image carrier 10Y, 10M, 10C, and 10K at the nip portion. , The carrier removal amount in the image carriers 10Y, 10M, 10C, and 10K is increased, and as a result, the carrier removal amount on the intermediate transfer member 40 is reduced. Alternatively, it may be increased as compared with a normal printing operation.

  The image carrier squeeze rollers 13Y, 13M, 13C, and 13K are controlled to rotate at a circumferential rotational speed that is faster than the rotational speeds of the image carriers 10Y, 10M, 10C, and 10K, and the image carrier squeeze roller 13Y. , 13M, 13C, and 13K may be controlled to rotate in a rotation direction opposite to the rotation direction of the image carriers 10Y, 10M, 10C, and 10K at the nip portion.

  As described above, according to the third embodiment of the present invention, when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer body 40 is increased as compared with the normal printing operation. Therefore, the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy by the optical sensor, so that color misregistration can be corrected with high accuracy. In the present embodiment, since the carrier collected by the image carrier squeeze rollers 13Y, 13M, 13C, and 13K is recycled, it can contribute to the efficient use of the liquid developer.

  Next, a fourth embodiment of the present invention will be described. FIGS. 6 and 7 are diagrams showing main components constituting an image forming apparatus according to the fourth embodiment of the present invention, and FIG. 8 is an image forming unit and developing device according to the fourth embodiment of the present invention. It is sectional drawing which showed these main components.

  In the third embodiment, the image carrier 10Y, 10M, 10C, and 10K squeeze devices are configured with one image carrier squeeze roller 13Y, 13M, 13C, and 13K, respectively. In the embodiment, each of the image carrier squeeze rollers 13Y ′, 13M ′, 13C ′, and 13K ′ is further provided, and the image carrier squeeze rollers 13Y, 13M, 13C, and 13K are provided as image carriers 10Y, 10M, It is configured to be able to come into and out of contact with 10C and 10K.

  Also in the fourth embodiment, when executing the color misregistration correction mode, control is performed to increase the carrier removal amount on the intermediate transfer body 40 as compared with the case of a normal printing operation. For this reason, in the fourth embodiment, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K that are separated from each other are brought into contact with each other during the color misalignment correction mode in the normal printing operation. Accordingly, more carriers are removed on the image carriers 10Y, 10M, 10C, and 10K than in the normal printing operation, thereby increasing the carrier removal amount on the intermediate transfer member 40.

When the color misregistration correction mode is executed, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K that are in contact with the image carrier are faster than the circumferential rotation speed of the image carriers 10Y, 10M, 10C, and 10K. It is controlled to rotate at the direction rotational speed, and the carrier removal amount in the image carriers 10Y, 10M, 10C, and 10K is increased, so that the carrier removal amount on the intermediate transfer member 40 is set in the case of a normal printing operation. Further, when the color misregistration correction mode is executed, the contacted image carrier squeeze rollers 13Y, 13M, 13C, and 13K are moved to the image carrier 10Y, 10M, and 10C at the nip portion. It is controlled to rotate in a rotation direction opposite to the rotation direction of 10K, and the carrier removal amount in the image carriers 10Y, 10M, 10C, and 10K is increased. As a result, the carrier removal amount on the intermediate transfer body 40 may be increased as compared with the case of a normal printing operation.

  Further, the image carrier squeeze rollers 13Y, 13M, 13C, and 13K that are in contact with each other are controlled to rotate at a circumferential rotational speed faster than the rotational speeds of the image carriers 10Y, 10M, 10C, and 10K. The squeeze rollers 13Y, 13M, 13C, and 13K may be controlled to rotate in a rotation direction opposite to the rotation direction of the image carriers 10Y, 10M, 10C, and 10K at the nip portion.

  As described above, according to the fourth embodiment of the present invention, when the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer body 40 is increased as compared with the case of the normal printing operation. Therefore, the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy by the optical sensor, so that color misregistration can be corrected with high accuracy. In the present embodiment, since the carrier collected by the image carrier squeeze rollers 13Y, 13M, 13C, and 13K is recycled, it can contribute to the efficient use of the liquid developer.

  Next, a fifth embodiment of the present invention will be described. FIG. 9 is a diagram showing the main components constituting the image forming apparatus according to the fifth embodiment of the present invention, and FIG. 10 is the main configuration of the image forming unit and developing device in the fifth embodiment of the present invention. FIG. 11 is a view of the intermediate transfer member according to the fifth embodiment of the present invention as viewed from the lower side after the formation of the resist mark.

  In the fifth embodiment, as an intermediate transfer body squeeze device, 52K provided between the transfer nip and the secondary transfer nip of the image carrier 10K and a location on the intermediate transfer body 40 to which the registration mark is transferred are applied. A resist mark squeeze device 80 in contact therewith is provided.

  The registration mark dedicated squeeze device 80 removes excess carrier liquid from a predetermined location on the intermediate transfer member 40 and increases the toner particle ratio in the visible image.

  Similar to the image carrier squeeze device 80, the registration mark dedicated squeeze device 80 is a registration mark intermediate transfer member squeeze roller 81 comprising an elastic roller member that is covered with an elastic member and is in sliding contact with the intermediate transfer member 40. A backup roller 82 disposed opposite to the registration mark intermediate transfer body squeeze roller 81 with the transfer body 40 interposed therebetween, and a cleaning blade 83 that presses and slides against the registration mark intermediate transfer body squeeze roller 81 to clean the surface. It has a function of recovering excess carriers from the resist marks primarily transferred to the transfer body 40. The carrier dropped from the cleaning blade 83 is collected by the first intermediate transfer member developer collecting unit and discarded into the second waste tank 441 through the pipe.

  In the present embodiment, for example, a registration mark is formed at a location outside the image formation area on the intermediate transfer body 40, and the registration mark intermediate transfer body squeeze roller 81 is applied at a location outside the image formation area on the intermediate transfer body 40. It can be configured to touch. When such an intermediate transfer member squeeze roller 81 for registration marks is provided, it is possible to suppress the carrier oil from moving to the back surface (surface on which no toner image is formed) of the intermediate transfer member 40. When the carrier oil moves to the back surface of the intermediate transfer member 40, the frictional force between the belt driving roller 41, the tension roller 42 and the intermediate transfer member 40 is reduced, and it becomes difficult to control the moving speed of the intermediate transfer member 40. is there. In the present embodiment, the registration mark intermediate transfer body squeeze roller 81 can suppress the movement of the carrier to the back surface of the intermediate transfer body 40, and thus it is possible to avoid such a reduction in frictional force.

  In this embodiment, since the registration mark intermediate transfer member squeeze roller 81 removes the carrier on the registration mark, the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy by the optical sensor. Therefore, color misregistration can be corrected with high accuracy.

  A registration mark is formed at a position in the image forming area on the intermediate transfer body 40, and the registration mark intermediate transfer body squeeze roller 81 is configured to be able to come into contact with and come into contact at a position in the image forming area on the intermediate transfer body 40. You can also

  In such a case, the registration mark intermediate transfer member squeeze roller 81 is separated during the normal printing operation, and the registration mark intermediate transfer member squeeze roller 81 is moved during the color misregistration correction mode. It is possible to increase the carrier removal amount in the vicinity of the registration mark transfer location on the intermediate transfer body 40 as compared with the case of a normal printing operation.

  Further, the registration mark dedicated squeeze device 80 controls the registration mark intermediate transfer body squeeze roller 81 to rotate at the same circumferential rotational speed as the movement speed of the intermediate transfer body 40, and executes the color misregistration correction mode. Controls the registration mark dedicated squeeze device 80 to rotate at a circumferential rotational speed faster than the moving speed of the intermediate transfer body 40, and the amount of carrier removal at the registration mark formation position of the intermediate transfer body 40 is set to a normal printing operation. It is made to increase compared with the case of.

  Although not shown in the drawings, during normal printing operation, the registration mark intermediate transfer member squeeze roller 81 is controlled to rotate in the rotational direction that is the same as the moving direction of the intermediate transfer member 40 and the nip portion. On the other hand, when the color misregistration correction mode is executed, the registration mark intermediate transfer body squeeze roller 81 is controlled to rotate in a rotation direction opposite to the moving direction of the intermediate transfer body 40 at the nip portion. The amount of carrier removal at the registration mark formation portion of the intermediate transfer body 40 is increased as compared with the case of a normal printing operation.

  Further, the registration mark intermediate transfer member squeeze roller 81 is controlled to rotate at a circumferential rotational speed faster than the moving speed of the intermediate transfer member 40, and the registration mark intermediate transfer member squeeze roller 81 is intermediately transferred at the nip portion. Control may be performed so that the body 40 is rotated in a rotation direction opposite to the moving direction of the body 40.

  Further, since the registration mark intermediate transfer body squeeze roller 81 is rotated in the direction opposite to the moving direction of the intermediate transfer body 40, the registration mark formed on the intermediate transfer body 40 may be disturbed. At this time, it is preferable to apply a bias voltage that presses the toner in the registration mark in the direction from the registration mark intermediate transfer body squeeze roller 81 to the intermediate transfer body 40.

  As described above, according to the fifth embodiment of the present invention, when the color misregistration correction mode is executed, the control for increasing the carrier removal amount on the registration mark of the intermediate transfer body 40 is performed. Since the registration mark position information can be accurately obtained without lowering the registration mark detection accuracy, color misregistration can be corrected with high accuracy.

  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 a first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating main components of the image forming unit and the developing device according to the first embodiment of the present invention. 1 is a diagram illustrating an intermediate transfer member squeeze device of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a diagram illustrating main components constituting an image forming apparatus according to a second embodiment of the present invention. It is sectional drawing which showed the main components of the image forming part and developing device in 2nd Embodiment of this invention. FIG. 10 is a diagram illustrating main components constituting an image forming apparatus according to a fourth embodiment of the present invention. FIG. 10 is a diagram illustrating main components constituting an image forming apparatus according to a fourth embodiment of the present invention. It is sectional drawing which showed the main components of the image formation part and developing device in 4th Embodiment of this invention. FIG. 10 is a diagram illustrating main components constituting an image forming apparatus according to a fifth embodiment of the present invention. It is sectional drawing which showed the main components of the image formation part and developing device in 5th Embodiment of this invention. It is the figure which looked at the intermediate transfer body in 5th Embodiment of this invention from the lower side after resist mark formation. 3 is a diagram illustrating an example of a resist mark formed on an intermediate transfer body 40. FIG.

Explanation of symbols

10Y, 10M, 10C, 10K ... image carrier, 11Y, 11M, 11C, 11K ... corona charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y, 13Y '... image carrier Body 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 ... toner compression corona generator, 30Y, 30M, 30C, 30K ... developing device, 31Y, 31M, 31C, 31K ... developer container, 32Y, 32M, 32C, 32K ... ani Roller, 31Y, 31M, 31C, 31K ... developer container, 33Y ... regulating blade, 34Y ... supply roller (supply roller), 40 ... intermediate transfer member (intermediate transfer belt), 41. Belt drive roller, 42 ... tension roller, 45 ... developer recovery unit, 46 ... intermediate transfer member cleaning blade, 47 ... second intermediate transfer member developer recovery unit, 50Y, 50M, 50C , 50K ... primary transfer portion, 51Y, 51M, 51C, 51K ... primary transfer backup roller, 52Y, 52M, 52C, 52K ... intermediate transfer member squeeze device, 53Y ... intermediate transfer member squeeze roller, 54Y: Intermediate transfer member squeeze backup roller, 55Y: Intermediate transfer member squeeze roller cleaning blade, 60 ... 2 Transfer unit 61 ... secondary transfer roller 62 ... secondary transfer roller cleaning blade 63 ... secondary transfer roller developer collecting unit 70Y ... first image carrier developer collecting 72Y ... Development roller developer collecting section, 73Y ... 3rd image carrier developer collection, 80 ... Registration mark squeeze device, 81 ... Registration mark intermediate transfer member squeeze roller, 82 ... Backup roller, 83 ... Intermediate transfer member squeeze roller cleaning blade for registration mark, 84K ... First intermediate transfer member developer recovery unit, 90 ... Optical sensor, 440 ... First waste liquid tank, 441 ..Second waste liquid tank, 400Y, 400M, 400C, 400K ... Stir tank, 401Y, 401M, 401C, 401K ... Developer supply tank 402Y, 402M, 402C, 402K ... buffer tank, 410 is a carrier tank, 410 ... carrier tank, 450Y, 450M, 450C, 450K ... first pump, 451Y, 451M, 451C, 451K ... Second pump, 452Y, 452M, 452C, 452K ... Third pump, 453Y, 453M, 453C, 453K ... Fourth pump

Claims (8)

A plurality of image carriers that carry developed images of liquid developers of different colors including carriers and toner particles for each color;
An intermediate transfer member to which a developed image is transferred from the plurality of image carriers and moves in a predetermined direction;
An optical sensor for detecting a developed image transferred to a predetermined location on the intermediate transfer member,
The registration marks are transferred to the predetermined locations of the intermediate transfer body by the plurality of image carriers, the registration marks are detected by the optical sensor, the color shift amount between different colors is calculated, and the calculated color shift amount is calculated. An image forming apparatus comprising a color misregistration correction mode for correcting, and increasing the amount of carrier removal on the intermediate transfer member when the color misregistration correction mode is executed. An intermediate transfer member squeeze roller disposed downstream of the plurality of image carriers, and when the color misregistration correction mode is executed, the rotational speed in the circumferential direction of the intermediate transfer member squeeze roller is set to the moving speed of the intermediate transfer member; The image forming apparatus according to claim 1, wherein the carrier removal amount on the intermediate transfer member is increased by setting it faster. When the color misregistration correction mode is executed, the carrier removal amount on the intermediate transfer member is increased by making the rotation direction of the intermediate transfer member squeeze roller face the moving direction of the intermediate transfer member at the nip portion. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A plurality of intermediate transfer member squeeze rollers disposed downstream of each of the plurality of image bearing members, and a circumferential rotational speed of the plurality of intermediate transfer member squeeze rollers is set to be higher than a moving speed of the intermediate transfer member; 4. The image forming apparatus according to claim 1, wherein the carrier removal amount on the intermediate transfer member is increased. The plurality of image carriers are provided with an image carrier squeeze roller that is in contact with the upstream side of the nip portion with the intermediate transfer member. When the color misregistration correction mode is executed, the image carrier squeeze roller 5. The carrier removal amount on the intermediate transfer member is increased by setting the circumferential rotational speed faster than the circumferential rotational speed of the image carrier. Image forming apparatus. The plurality of image carriers are provided with an image carrier squeeze roller on the upstream side of the nip portion with the intermediate transfer member so as to be able to come into contact with and come into contact with each other, and when executing the color misregistration correction mode, the image carrier 6. The image forming apparatus according to claim 1, wherein a carrier removal amount on the intermediate transfer member is increased by a squeeze roller coming into contact with the image carrier. A registration mark intermediate transfer body squeeze roller that is arranged downstream of the plurality of image carriers and abuts in the vicinity of a predetermined position of the intermediate transfer body to which the registration mark is transferred, and when the color misregistration correction mode is executed; The image forming apparatus according to claim 1, wherein a carrier removal amount on the intermediate transfer member is increased by the registration mark intermediate transfer member squeeze roller. A plurality of image carriers that carry developed images of liquid developers of different colors including carriers and toner particles for each color;
An intermediate transfer member to which a developed image is transferred from the plurality of image carriers and moves in a predetermined direction;
An optical sensor for detecting a developed image transferred to a predetermined location on the intermediate transfer body, and a control method for an image forming apparatus,
The registration marks are transferred to the predetermined locations of the intermediate transfer body by the plurality of image carriers, the registration marks are detected by the optical sensor, the color shift amount between different colors is calculated, and the calculated color shift amount is calculated. A control method for an image forming apparatus, comprising a color misregistration correction mode for correcting, and increasing the amount of carrier removal on the intermediate transfer member when the color misregistration correction mode is executed.

Images