JP2006309009A - Liquid image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid image forming apparatus which can shorten a first printing time, also, reduce the quantity of carrier liquid to a recording medium, consequently, suppressing bleeding at a transferred image (toner image) on the recording medium, then, can improve dot reproducibility in a pixel image. <P>SOLUTION: The liquid image forming apparatus includes an intermediate transfer belt 43 on which the toner images formed on a plurality of image forming means 5 to 8 arranged in tandem are transferred to superpose the colors, and a secondary transfer means 9 for transferring the toner images color-superposed on the intermediate transfer belt 43 in a mass. The liquid image forming apparatus further includes a third transfer means 10 for transferring the toner images color-superposed on the secondary transfer means 9 in a mass and a fourth transfer means 11 for transferring the toner images on the third transfer means 10 to the recording medium in a mass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid image forming apparatus employed in a copying machine, a facsimile machine, a printer, and the like.

  A liquid image forming apparatus using a liquid developer containing toner particles and a carrier liquid develops a latent image by applying a liquid developer to a photoreceptor on which an electrostatic latent image is formed, and is developed and formed. The toner image thus transferred is transferred and fixed on a recording medium such as an intermediate transfer member or paper.

In such a liquid image forming apparatus, when the toner image is transferred to an intermediate transfer member or a recording medium, if the carrier liquid is excessive, there is an adverse effect on melting of the toner image during fixing.
Therefore, in order to improve the transfer efficiency of the toner image, in Patent Document 1, the intermediate transfer member supporting the toner image is heated to increase the adhesive force between the recording medium and the toner. The melting is not adversely affected. In Patent Document 2, a carrier liquid removing unit is separately provided on the intermediate transfer member, and the intermediate transfer member supporting the toner image is heated to increase the adhesive force between the recording medium and the toner. ing.

  However, the intermediate melt transfer systems such as Patent Document 1 and Patent Document 2 are not preferable because the intermediate transfer member needs to keep the temperature of the intermediate transfer member constant at all times. Further, not only a heating device for the intermediate transfer member is required, but a separate cooling device or the like is required, resulting in high costs.

  Therefore, a technique for removing excess carrier liquid by repeating transfer by applying an electric field and pressure can be considered. Conventionally, an apparatus for primary transfer from a photosensitive member to a primary intermediate transfer member by applying an electric field and pressure, and further transferring the primary transferred toner image to a recording medium by secondary transfer by applying an electric field and pressure. It is known. In addition to the primary transfer and the secondary transfer as described above, a tandem liquid image forming apparatus that removes the carrier liquid by performing a tertiary transfer can be considered. The outline of this apparatus will be described with reference to FIG.

  A tandem type liquid image forming apparatus for forming a color image has a photosensitive drum 210, a main charging device 220, an exposure for each color type of black (BK), magenta (M), cyan (C), and yellow (Y). A set of image forming units 200 each including a device 230, a liquid developing device 240, a cleaning device 250, a charge removal lamp 260, and the like are provided.

  In this liquid image forming apparatus, for each color type, the electrostatic latent image formed on the photosensitive drum 210 is developed with a liquid developer in which toner is dispersed in an insulating carrier liquid. That is, the photosensitive drum 210 is supplied with a liquid developer from the developing roller 242 of the liquid developing device 240, and the electrostatic latent image on the photosensitive drum 210 is developed by the supplied liquid developer. Is done. Further, the developed and visualized toner images on the liquid developing device 240 match each other for each color type by the action of an electric field and pressure on the intermediate transfer belt 300 located above the photosensitive drum 210. In this way, the images are superimposed and transferred as a transferred image.

  The primary transferred image is further transferred from the intermediate transfer belt 300 wound around the driving roller 310 and the driven roller 320 to the secondary transfer roller 400 by the action of an electric field and pressure. When a recording medium such as recording paper is transferred and pressed between the backup roller 410 and the secondary transfer roller 400, the transfer image is transferred from the secondary transfer roller 400 to the recording medium by the action of an electric field and pressure. Is tertiary transferred.

  Then, the recording medium that requires the third-transferred toner image is transferred to a fixing unit 440 positioned above the secondary transfer roller 400 and the backup roller 410. The fixing unit 440 includes a fixing unit 440 including a pair of fixing rollers 420 and 430. Each of the fixing rollers 420 and 430 includes a fixing heater (not shown), and heats the recording medium that is pressed and passed through the identification fixing heater to a predetermined temperature necessary for fixing, thereby fixing a full-color image. Process.

In the liquid image forming apparatus in which the image forming unit 200 is arranged in a tandem type, the image forming unit 200 is not arranged above the intermediate transfer belt 300 so that the liquid developer dripping from the photosensitive drum 210 is not contaminated. The image forming unit is disposed below the intermediate transfer belt 300.
Japanese Patent Laid-Open No. 2001-60046 JP 2003-345145 A

However, in the case of an apparatus for transferring a toner image to a recording medium by tertiary transfer as described above, there is a problem that time is required for first printing for the following reason.
First, as described above, when the image forming unit 200 is disposed above the intermediate transfer belt 300, the liquid developer from the image forming unit 200 drops on the intermediate transfer belt 300, which causes a problem of contamination. The forming unit 200 is disposed below the intermediate transfer belt 300.

  When the image forming unit 200 arranged in a tandem type is arranged below the intermediate transfer belt 300, the rotation direction of the intermediate transfer belt 300 is shown in FIG. 4 from the viewpoint of easy removal of the recording medium from the image forming apparatus. The direction of rotation A is preferred.

  That is, if the rotation direction is the direction opposite to the rotation direction A shown in FIG. 4, the moving direction B of the recording medium moved by the secondary transfer roller 400 is the downward direction opposite to FIG. There is a problem that it is difficult for a person to take out the recording medium from the lower part of the apparatus. In this case, it may be possible to form a transfer path for transferring the recording medium once moved to the lower part of the apparatus to the upper part of the apparatus, but a space for forming the transfer path is required, and the apparatus is enlarged. There is a problem of high costs.

  For this reason, the rotation direction of A shown in FIG. 4 is good. In this direction, when fast printing is performed, the toner image on which color is superimposed on the intermediate transfer belt 300 is temporarily moved to the right as shown in FIG. After moving in the direction, there is a distance until it is reversed by the driven roller 320 and moved to the driving roller 310, so that it takes time for the first print. That is, the position at which the secondary transfer is performed from the position at which the primary transfer is finally performed among the plurality of image forming units 200 (the position of the nip between the image forming unit 200 where the black image is formed and the intermediate transfer belt 300). There is a problem that the distance to (the nip position between the intermediate transfer belt 300 and the secondary transfer roller 400) becomes long.

  An object of the present invention is that the first print time can be shortened and the carrier liquid to the recording medium can be reduced. As a result, the transferred image (toner image) on the recording medium does not blur. Another object of the present invention is to provide a liquid image forming apparatus in which image dot reproducibility is improved.

  In order to solve the above-mentioned problems, the invention described in claim 1 includes a primary transfer image carrier that transfers and superimposes toner images from a plurality of image forming means arranged in tandem, and the primary transfer image. A secondary transfer image carrier that batch-transfers toner images superimposed on color on the carrier, a tertiary transfer image carrier that batch-transfers toner images superimposed on the secondary transfer image carrier, and the tertiary The gist of the present invention is a liquid image forming apparatus having a quaternary transfer body that collectively transfers a toner image on a transfer image carrier onto a recording medium.

According to a second aspect of the present invention, in the first aspect, the primary transfer image carrier is made of an endless resin belt.
According to a third aspect of the present invention, in the first or second aspect, the tertiary transfer image carrier is provided with an elastic layer on the surface.

  According to a fourth aspect of the present invention, in the third aspect, the tertiary transfer image carrier is a roller.

  According to the first aspect of the present invention, the layout configuration is such that the image forming means is disposed below the primary transfer image carrier effectively to prevent contamination of the transfer toner onto the primary transfer image carrier from the image forming means. In this case, by adding one quaternary transfer member to the tertiary transfer method, the first print time can be shortened.

  In general, the image forming means is preferably arranged below the primary transfer image carrier with respect to the primary transfer image carrier. This is because, if the image forming means is disposed above the primary transfer image carrier, the toner image transferred to the primary transfer image carrier when the liquid developer leaks from the image forming means ( That is, the transfer toner) is contaminated.

  According to the first aspect of the present invention, the carrier liquid passes through the secondary transfer image carrier and the tertiary transfer image carrier before the transfer to the recording medium, so that the carrier liquid is transferred to the primary transfer body during the secondary transfer. It is recovered by the surface tension of the secondary transfer member and is recovered by the surface tension of the secondary transfer member at the time of the third transfer. For this reason, the amount of carrier liquid at the time of quaternary transfer can be reduced. As described above, since the transfer image (toner image) on the recording medium is not blurred by lowering the carrier liquid, the dot reproducibility of the pixel image is improved.

  According to the second aspect of the present invention, when the primary transfer image carrier is an endless belt, it is necessary to apply tension so that the belt is driven and rotated reliably without slipping. Tension is applied with a roller. For this reason, the curvature of the belt that travels at the time of driving changes greatly at the plurality of portions, and is repeatedly stressed.

  Therefore, if a resin belt is used as the primary transfer image carrier, the thickness of the belt can be reduced, so that deformation of the belt in the thickness direction of the belt and in the rotational circumferential direction of the portion wound around the roller is suppressed. it can. As a result, the color misregistration in the tandem type image forming apparatus can be reduced, and the creep deformation of the belt when used for a long time can be prevented.

  If the primary transfer image carrier is a drum and a liquid developer is used, the layout of the image forming means is arranged on the lower side of the drum, which is an effective position for preventing contamination. It will be. On the other hand, the upper part of the drum is inevitably arranged in a semicircular arc shape upward.

  On the other hand, when the primary transfer image carrier is a belt, the belt is arranged so as to be hung between a plurality of rollers. For this reason, the layout of the image forming means is arranged on the lower side of the belt, which is an effective position for preventing contamination. Unlike the drum, the upper part of the belt is arranged in a semicircular arc shape. Therefore, the arrangement space of the primary transfer image carrier can be reduced as compared with the case of the drum.

According to the third aspect of the present invention, the elastic layer is provided on the tertiary transfer image carrier, so that the transfer to the concave portion of the recording medium (not depending on the melt transfer system) is possible.
According to the fourth aspect of the present invention, the surface transfer layer of the surface transfer layer due to the change in the curvature of the elastic layer is compared with the case where the tertiary transfer image carrier is configured as a roller by using a roller configuration. Can prevent cracks, wrinkles and creep deformation.

  If the tertiary transfer image carrier is of a belt type, an elastic layer is provided on the belt, so that the thickness of the belt increases, and the thickness direction of the belt and the rotational circumference of the portion wound around the roller are increased. The deformation of the belt in the direction cannot be suppressed, and the creep deformation of the belt when used for a long time cannot be prevented.

Hereinafter, an embodiment in which the present invention is embodied in a tandem color image forming apparatus (hereinafter simply referred to as a liquid image forming apparatus) will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram of a liquid image forming apparatus. The liquid image forming apparatus includes a registration roller pair 3 that conveys paper as a recording medium from a sheet feeding unit (not shown), a belt conveying unit 4, a first image forming unit 5, a second image forming unit 6, and a third image. The image forming apparatus includes a forming unit 7, a fourth image forming unit 8, a secondary transfer unit 9, a tertiary transfer unit 10, a quaternary transfer unit 11, a fixing unit 12, and the like.

  The registration roller pair 3 is provided on the recording medium conveyance path, and conveys the paper conveyed from a paper supply unit (not shown) to the tertiary transfer unit 10 and the quaternary transfer unit 11. The belt conveying unit 4 includes a driving roller 41, a driven roller 42, and an endless intermediate transfer belt 43 that is stretched over the two rollers. The intermediate transfer belt 43 is made of a conductive resin belt. By using a resin belt, creep deformation can be reduced. Examples of the resin belt include polyimide, but the material is not limited to this material.

  The intermediate transfer belt 43 maintains an appropriate tension by the tension roller 44. In this state, the driving roller 41 receives a driving force from a driving motor (not shown), and the outer peripheral speed of the photosensitive drum 51 in each image forming unit and the outer peripheral speed of the intermediate transfer belt 43 of the belt conveying unit 4 are constant. It is driven to become.

  The first to fourth image forming units 5 to 8 shown in FIG. 1 are for black (BK), magenta (M), cyan (C), and yellow (Y) from the left side in the figure, and are all substantially the same. It is a unit of composition. Here, for convenience of explanation, the configuration of the first image forming unit 5 will be described with reference to FIG. In other image forming units, the same components as those of the first image forming unit 5 are denoted by the same reference numerals.

  The first image forming unit 5 includes a photosensitive drum 51, a main charging device 52, an LPH (LED PRINT HEAD) 53 as an exposure unit, a liquid developing device 54, a primary transfer unit 55, a cleaning device 56, and a static elimination lamp 57. The unit is configured as a unit by being assembled in a housing made of resin, and is attached to an apparatus main body (not shown).

  The photosensitive drum 51 is an amorphous silicon drum and is charged by the main charging device 52 so that the dark potential at the developing position is about 300V. The LPH 53 irradiates the surface of the charged photoconductive drum 51 with light corresponding to image information, whereby an electrostatic latent image is formed on the surface of the photoconductive drum 51. The photosensitive drum 51 corresponds to an image carrier. The LPH 53 is used to reduce the size of the unit, but an LSU (laser scanning unit) may be used.

  As shown in FIG. 3, the liquid developing device 54 includes a storage tank 71 that stores the liquid developer 70. Inside the storage tank 71, a developing roller 72 as a developer carrier, a coating roller 73, a pumping roller 74, a doctor blade 75, a developing cleaning blade 76, and a pair of stirring screws 77a and 77b are provided. It has been. The developing roller 72, the application roller 73, the scooping roller 74, and the stirring screws 77a and 77b are rotationally driven by a drive motor (both not shown) through a drive transmission mechanism including a gear train and the like.

  The liquid developer 70 is adjusted so that the toner is dispersed at a high concentration in a carrier liquid made of a nonpolar insulating liquid such as silicone oil. The agitating screws 77a and 77b circulate and agitate the liquid developer 70. A part of the pumping roller 74 is immersed in the liquid developer 70, and the liquid developer 70 thus pumped is rotated in contact with the coating roller 73 to apply the liquid developer 70 to the coating roller 73.

  The application roller 73 forms a thin layer of the liquid developer 70 on the development roller 72 by applying the liquid developer 70 on the development roller 72. In the developing area G on the photosensitive drum 51, the latent image is developed by the liquid developer 70). Further, after development, the liquid developer 70 remaining on the developing roller 72 is removed from the developing roller 72 by the developing cleaning blade 76.

  The liquid developing device 54 stirs and mixes the liquid developer so as to have a predetermined concentration, and an electrostatic latent image of a portion of the photosensitive drum 51 irradiated with the liquid developer by the developing roller 72. To form a toner image on the photosensitive drum 51. The dark potential of the photosensitive drum 51 is set to 300V, the developing bias is set to 200V, and the post-exposure potential is set to 20V. That is, the dark potential corresponds to the white portion of the image, the post-exposure potential corresponds to the black portion of the image, and this difference is a so-called contrast potential. The toner image developed from the electrostatic latent image formed as described above is transferred to the intermediate transfer belt 43 corresponding to the nip with the primary transfer means 55.

  The primary transfer means 55 uses a transfer roller in this embodiment, and a voltage having a polarity opposite to the surface potential of the photosensitive drum 51 (that is, the primary transfer bias) is set to −300V and applied. Yes. The intermediate transfer belt 43 corresponds to a primary transfer image carrier.

  In this embodiment, the space between the photosensitive drum 51 and the intermediate transfer belt 43 is controlled by pressure, and the contact pressure (that is, linear pressure) between the intermediate transfer belt 43 and the photosensitive drum 51 is 0. The primary transfer means 55 is urged by the urging means such as a spring (not shown) so as to come into contact with the photosensitive drum 51 side via the intermediate transfer belt 43 so as to be .01 kg / mm.

  The toner that has not been transferred onto the photosensitive drum 51 is scraped off by the cleaning device 56 in the next process. A cleaning roller 62 and a cleaning blade 60 are provided in the cleaning case 61 of the cleaning device 56. The cleaning roller 62 is in pressure contact with the photosensitive drum 51 and is rotated in the nip direction of the photosensitive drum 51 and the counter direction by a drive motor (not shown). The cleaning blade 60 collects and removes the untransferred toner on the photosensitive drum 51 by making a counter contact with the photosensitive drum 51 on the downstream side from the position of the cleaning roller 62 in the rotation direction of the photosensitive drum 51.

  The photosensitive drum 51 is neutralized by a neutralizing lamp 57 in order to lower the residual potential on the surface and make it uniform, and thereafter, it is prepared for the next series of processes. The potential setting for image formation in this manner varies depending on the characteristics of the photosensitive drum 51, the toner performance, and the environment. The liquid image forming apparatus develops images corresponding to magenta, cyan, and yellow on the photosensitive drum by the second to fourth image forming means 6 to 8 in the same manner as the first image forming means 5. Then, a full-color image (that is, a toner image) is formed by sequentially and repeatedly transferring onto the intermediate transfer belt 43 without deviation.

  Returning to FIG. 1 again, image formation after transfer from the photosensitive drum 51 will be described. In this embodiment, the secondary transfer unit 9 as a secondary transfer image carrier is composed of a secondary transfer roller, and is rotated in the same direction as the rotation direction of the intermediate transfer belt 43 at the nip by a drive motor (not shown).

The distance between the centers of the secondary transfer unit 9 and the drive roller 41 is controlled so that the nip depth between the secondary transfer unit 9 and the intermediate transfer belt 43 is 0.5 mm.
The secondary transfer roller is made of conductive rubber. Examples of the conductive rubber include conductive NBR (nitrile butyl rubber). The secondary transfer unit 9 is disposed at the secondary transfer position of the intermediate transfer belt 43. The secondary transfer position is a position where the secondary transfer unit 9 faces the driving roller 41 and is pressed against the intermediate transfer belt 43. The drive roller 41 is made of a metal roller so as to have conductivity, and is grounded so as to have a ground potential.

  On the other hand, a secondary transfer bias is applied to the secondary transfer unit 9. In the present embodiment, the secondary transfer bias is −400V. When the secondary transfer unit 9 and the intermediate transfer belt 43 are brought into contact with each other at the nip and rotate with each other, a full-color image (that is, the intermediate transfer belt 43 is transferred to the secondary transfer unit 9 by the action of an electric field and pressure). Toner image) is secondarily transferred.

  The toner that has not been transferred onto the intermediate transfer belt 43 is scraped off by the intermediate transfer cleaning unit 13. The intermediate transfer cleaning unit 13 includes an intermediate transfer cleaning roller 13a and an intermediate transfer cleaning blade 13b. The intermediate transfer cleaning roller 13a is in pressure contact with the intermediate transfer belt 43, and is rotated in the same direction as the rotation direction of the intermediate transfer belt 43 at the nip by a drive motor (not shown). The intermediate transfer cleaning blade 13b counter-contacts the intermediate transfer belt 43 on the downstream side from the position of the intermediate transfer cleaning roller 13a in the rotational direction of the intermediate transfer belt 43, thereby removing untransferred toner on the intermediate transfer belt 43. Collect and remove.

Next, tertiary transfer will be described.
A tertiary transfer unit 10 as a tertiary transfer image carrier is disposed at a tertiary transfer position of the secondary transfer unit 9. The tertiary transfer position is a position where the secondary transfer unit 9 comes into pressure contact with the tertiary transfer unit 10. The tertiary transfer unit 10 includes a tertiary transfer roller, and is rotated in the nip in the same direction as the rotation direction of the secondary transfer unit 9 by a drive motor (not shown).

  The distance between the centers of the tertiary transfer unit 10 and the secondary transfer unit 9 is controlled so that the nip depth between the tertiary transfer unit 10 and the secondary transfer unit 9 is 0.5 mm. In the tertiary transfer means 10, a conductive elastic layer 10b is formed with a predetermined thickness on the surface of a cylindrical cored bar 10a, and a toner image releasability is formed on the surface of the elastic layer 10b. A coating layer 10c for improving the above is formed. In the present embodiment, the thickness of the elastic layer 10b is 0.5 mm.

  As the conductive elastic layer 10b, conductive rubber is preferable. Examples of the conductive rubber include electrodynamic polyurethane rubber, conductive silicon rubber, conductive NBR (nitrile butyl rubber), conductive epichlorohydrin rubber, and conductive fluorine rubber. The coating layer 10c is preferably a fluorine-based or urethane-based coating layer.

  A tertiary transfer bias is applied to the tertiary transfer means 10. In the present embodiment, the tertiary transfer bias is −600V. When the tertiary transfer unit 10 and the secondary transfer unit 9 come into contact with each other at the nip and rotate with each other, a full color image (from the secondary transfer unit 9 to the tertiary transfer unit 10 is applied by the action of an electric field and pressure). That is, the toner image) is thirdarily transferred. The toner that has not been transferred onto the secondary transfer unit 9 is scraped off by a cleaning blade 9 a that is in counter contact with the rotational direction of the secondary transfer unit 9.

Next, quaternary transfer will be described.
The quaternary transfer means 11 comprises a conductive roller formed by blending, for example, NBR (nitrile butyl rubber) with epichlorohydrin, and is rotated in the same direction as the rotation direction of the tertiary transfer means 10 at the nip by a drive motor (not shown). The

  In the present embodiment, the pressure between the quaternary transfer unit 11 and the tertiary transfer unit 10 is controlled by pressure, and the contact pressure between the quaternary transfer unit 11 and the tertiary transfer unit 10 (that is, linear pressure). ) Is urged so as to abut on the side of the tertiary transfer means 10 by an urging means such as a spring (not shown) so that the pressure becomes 0.01 kg / mm.

  A quaternary transfer bias is applied to the quaternary transfer means 11 by a constant current source 11a (see FIG. 1). In the present embodiment, a quaternary transfer bias is applied by the constant current source 11a, and the bias is controlled so that the current flowing into the tertiary transfer means 10 becomes −20 μA. Note that the value of the inflow current is not limited to −20 μA, and may be another value.

  Then, the quaternary transfer unit 11 and the tertiary transfer unit 10 are rotated, and the paper conveyed between the quaternary transfer unit 11 and the tertiary transfer unit 10 via the registration roller pair 3 on the recording medium conveyance path. When the toner passes, a full color image (that is, a toner image) is fourtharily transferred from the tertiary transfer means 10 to the paper by the action of the electric field and pressure. At this time, the elastic layer 10b of the tertiary transfer means 10 can be easily transferred to the concave portion of the paper surface. The toner that has not been transferred onto the tertiary transfer unit 10 is scraped off by the cleaning blade 10 d that is in counter contact with the rotational direction of the tertiary transfer unit 10.

  Thereafter, the paper on which the full-color image is quaternarily transferred is separated from the quaternary transfer means 11 and the tertiary transfer means 10 and conveyed to the fixing means 12. The fixing unit 12 includes a first fixing roller 12a and a second fixing roller 12b. Each fixing roller includes a fixing heater (not shown), and the identification fixing heater is controlled to a predetermined temperature necessary for fixing. Due to this temperature, a full-color image is fixed on the paper that is in pressure contact with both rollers. Then, after the fixing process is performed by the fixing unit 12, the paper is discharged to a discharge tray (not shown) through a discharge conveyance path (not shown).

  As described above, the liquid image forming apparatus is effective in preventing contamination of the transfer toner onto the intermediate transfer belt 43 from the first to fourth image forming units 5 to 8. The layout configuration is such that each image forming unit is arranged below.

  As shown in FIG. 1, the toner image on the intermediate transfer belt 43 that has passed through the first to fourth image forming units 5 to 8 and is color-superposed is the first image closest to the drive roller 41. Since it moves closer from the forming means 5 side, the first print time can be shortened.

  That is, the position (intermediate transfer belt 43 and secondary transfer means 9) from the position where the primary transfer was last performed (that is, the nip position between the first image forming means 5 and the intermediate transfer belt 43) to the secondary transfer. Since the distance of the nip position) is shorter than the example of FIG. 4, the first print time can be shortened.

  Further, according to the present embodiment, the carrier liquid is recovered by the surface tension of the primary transfer member during the secondary transfer by passing through the secondary transfer unit 9 and the tertiary transfer unit 10 before the transfer to the paper. Further, it can be recovered by the surface tension of the secondary transfer member at the time of the third transfer. For this reason, the amount of carrier liquid at the time of quaternary transfer can be reduced. As described above, since the transfer image (toner image) on the recording medium is not blurred by lowering the carrier liquid, the dot reproducibility of the pixel image is improved.

  Furthermore, in this embodiment, since a resin belt is used as the intermediate transfer belt 43 and the thickness of the belt can be reduced, deformation of the belt in the thickness direction of the belt and the rotational circumferential direction of the portion wound around the roller is suppressed. it can. As a result, the color misregistration in the tandem type image forming apparatus can be reduced, and the belt can be prevented from being deformed when used for a long time.

Furthermore, in this embodiment, the elastic layer 10b is provided in the tertiary transfer means 10, so that the transfer to the concave portion of the paper is possible without depending on the melt transfer method.
Further, in this embodiment, since the tertiary transfer unit 10 has a roller configuration, the surface coating layer is cracked or wrinkled due to a change in the curvature of the elastic layer, compared to the case where the tertiary transfer unit 10 is a belt type. Can prevent creep deformation.

In addition, this invention is not limited to the said embodiment, You may change as follows.
In the above embodiment, the intermediate transfer belt 43 is provided. However, instead of the intermediate transfer belt 43, an intermediate transfer drum may be used as a primary transfer image carrier.

1 is a schematic view of a liquid image forming apparatus according to an embodiment embodying the present invention. Similarly the principal part enlarged view. Schematic of image forming means. FIG. 3 is a schematic view of a tertiary transfer type image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 ... Belt conveying means 5 ... 1st image forming means 6 ... 2nd image forming means 7 ... 3rd image forming means 8 ... 4th image forming means 9 ... Secondary transfer means (secondary transfer image carrier) )
10: Tertiary transfer means (tertiary transfer image carrier)
10b: elastic layer 11: quaternary transfer means (quaternary transfer body)
43. Intermediate transfer belt (primary transfer image carrier)

Claims (4)

A primary transfer image carrier that transfers and superimposes toner images from a plurality of image forming means arranged in tandem;
A secondary transfer image carrier that collectively transfers toner images superimposed on the primary transfer image carrier;
A tertiary transfer image carrier that collectively transfers toner images superimposed on the secondary transfer image carrier;
A liquid image forming apparatus having a quaternary transfer body that collectively transfers a toner image on the tertiary transfer image carrier onto a recording medium.   The liquid image forming apparatus according to claim 1, wherein the primary transfer image carrier is made of an endless resin belt.   The liquid image forming apparatus according to claim 1, wherein the tertiary transfer image carrier has an elastic layer provided on a surface thereof.   The liquid image forming apparatus according to claim 3, wherein the tertiary transfer image carrier is a roller.

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