JP2009037202A - Control method of image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that is free from a phenomenon in which a residue of a dispersant dissolved in the liquid carrier of liquid developer on an intermediate transfer belt results in a nonuniform image. <P>SOLUTION: A control method of the image forming apparatus is disclosed. The apparatus includes a latent image carrier; a development apparatus for developing a liquid developer containing a toner, a carrier liquid and a dispersant soluble in the carrier liquid therein on the latent image carrier; an intermediate transfer medium to which a developer image developed on the latent image carrier is transferred; a transfer apparatus for transferring the developer image on the intermediate transfer medium to a transfer material; and a dispersant collecting liquid application means for applying a dispersant collecting liquid on the intermediate transfer medium. The method includes performing the control such that after finishing of transfer of the developer image onto intermediate transfer medium, application of the dispersant collecting liquid on the intermediate transfer medium is started by the dispersant collecting liquid application means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device control method and an image forming apparatus for developing an electrostatic latent image formed on a latent image carrier such as a photoreceptor with a liquid developer composed of toner, a carrier liquid, and a dispersant. The present invention relates to a method for controlling an image forming apparatus such as a copying machine, a printer, and a facsimile, and an image forming apparatus, in which a liquid developer image on a developed latent image carrier is transferred to a transfer material such as paper to obtain an image. is there.

In the image forming apparatus using the liquid developer, an image forming apparatus is proposed in which the toner is mainly collected by the surplus toner collecting means by cleaning to collect the surplus toner and the carrier liquid is left on the photosensitive member. (For example, refer to Patent Document 1).
In order to suppress the generation of excess toner, a method of cleaning the liquid developer with a urethane cleaning blade or the like has been proposed (see, for example, Patent Document 2).

However, when the toner is collected by cleaning at the end of printing and the carrier liquid is left on the latent image carrier, the wettability of the surface of the latent image carrier is caused by the dispersant remaining in the carrier liquid on the photosensitive member. Since it is affected, it causes density unevenness in the developer on the latent image carrier during subsequent development.
Further, when printing is completed with the carrier liquid remaining on the latent image carrier, the carrier liquid flows downward due to gravity, causing a problem of contaminating the inside of the apparatus. In addition, even when cleaning is performed with a cleaning blade, the dispersant remains on the latent image carrier together with part of the carrier liquid, and the characteristics of the developer may change during subsequent development, resulting in density unevenness. It was.
JP 2002-268394 A JP 2002-287517 A

  In the present invention, as a result of the dispersion agent contained in the liquid developer remaining on the latent image carrier, the development characteristics are changed by the dispersion agent remaining when the latent image is developed, and density unevenness or the like is formed in the formed image. It is an object of the present invention to prevent the occurrence of the phenomenon that the image quality deteriorates due to the phenomenon described above.

  The present invention relates to a developing device that develops a latent image carrier, a liquid developer containing toner, a carrier liquid, and a dispersant soluble in the carrier liquid onto the latent image carrier, and the latent image carrier. An intermediate transfer medium onto which the developed developer image is transferred, a transfer device for transferring the developer image on the intermediate transfer medium to a transfer material, and a dispersion for applying a dispersant recovery liquid onto the intermediate transfer medium And after the completion of the transfer of the developer image onto the intermediate transfer medium, the application of the dispersant recovery liquid is started on the intermediate transfer medium by the dispersant recovery liquid application means. Since the control method of the image forming apparatus is controlled as described above, even if the dispersant that is soluble in the carrier liquid remains without being removed by the intermediate transfer medium cleaning device or remains on the intermediate transfer medium, Dissolvable liquid By applying the intermediate transfer medium, dispersing agent recovered solution after dissolving and diluting the dispersant on the latent image bearing member, it is possible to reliably remove with a dispersant collecting liquid.

  Further, since the separation of the transfer roller is a control method of the image forming apparatus that continues until the end of the operation of removing the dispersant by application of the dispersant recovery liquid, a liquid capable of dissolving the dispersant is transferred to the transfer roller. It does not adhere and does not cause problems such as the application liquid adhering to a transfer material such as paper.

  Further, since the separation of the transfer roller is the control method of the image forming apparatus described above, the separation of the transfer roller is continued until the end of the operation of removing the dispersant by application of the dispersant recovery liquid. The dispersant recovery liquid adheres to prevent the transfer material from being soiled.

  After the transfer from the latent image carrier to the intermediate transfer medium is completed, the rotation speed of the intermediate transfer medium is set to rotate the intermediate transfer medium when the developer image is transferred from the latent image carrier to the intermediate transfer medium. The method of controlling the image forming apparatus, wherein the image forming apparatus is faster than the speed. As described above, when the speed of the intermediate transfer medium is higher than that at the time of transfer from the latent image carrier to the intermediate transfer medium, the dispersion agent recovery liquid applied to the intermediate transfer medium is brought into contact with the latent image carrier. Since the amount to be transferred becomes small and most of the liquid applied on the intermediate transfer medium can be retained, it is possible to effectively remove the dispersant on the intermediate transfer medium.

In addition, before the application start position of the dispersant recovery liquid applied by the dispersant recovery liquid application unit on the intermediate transfer medium reaches the transfer portion for transferring the intermediate transfer medium developer image from the latent image carrier. And a method of controlling the image forming apparatus, wherein the latent image carrier is separated from the intermediate transfer medium.
Thus, by separating the latent image carrier, it is possible to prevent the liquid applied by the coating means from moving to the latent image carrier.

Further, after the latent image carrier and the intermediate transfer medium are in contact with each other, the latent image carrier and the latent image carrier are rotated until the dispersion liquid is applied to the latent image carrier for one round or more. The method of controlling the image forming apparatus, wherein a dispersion recovery liquid is applied to the intermediate transfer medium by rotating the intermediate transfer medium at least once around the intermediate transfer medium while being spaced apart from the intermediate transfer medium.
In this way, the intermediate transfer medium is caused to make a round from the rear end of the image forming position, and after the liquid developer residue is removed from the intermediate transfer medium by the intermediate transfer medium cleaning device, the liquid in which the dispersant can be dissolved is applied. As a result, the effect of removing the dispersant by the dispersant recovery liquid can be enhanced.

  In addition, a rotatable developing roller that conveys a liquid developer containing a latent image carrier, a toner for developing an electrostatic latent image, a carrier liquid, and a dispersant that can be dissolved in the carrier liquid. A developing device for developing a latent image on the image carrier, a rotatable intermediate transfer medium to which a developer image on the latent image carrier is transferred, an intermediate transfer medium cleaning device for cleaning the intermediate transfer medium, Since the image forming apparatus is provided with an application unit that applies the dispersant recovery liquid onto the intermediate transfer medium, the application is performed by the application unit that applies the dispersant recovery liquid in which the dispersant in the liquid developer can be dissolved, After the dispersant on the intermediate transfer medium is dissolved and diluted, it can be removed by an intermediate transfer medium cleaning device.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram partially showing an example of an embodiment of an image forming apparatus according to the present invention.
In this example, the image forming apparatus 1 has photosensitive bodies 2Y, 2M, 2C, and 2K arranged in a tandem type in the order of development as yellow (Y), magenta (M), cyan (C), and black (K) latent image carriers. It is a thing.
In each of the photoreceptors 2Y, 2M, 2C, and 2K, 2Y represents a yellow photoreceptor, 2M represents a magenta photoreceptor, 2C represents a cyan photoreceptor, and 2K represents a black photoreceptor. Similarly, the members of the respective colors are represented by adding Y, M, C, and K of the respective colors to the reference numerals of the members.
Each of the photoreceptors 2Y, 2M, 2C, and 2K is composed of a photoreceptor drum in the example shown in FIG. Each of the photoconductors 2Y, 2M, 2C, and 2K can also be configured as an endless belt.

  These photoreceptors 2Y, 2M, 2C, and 2K are configured to rotate clockwise as indicated by arrows in FIG. 1 during operation. Around each photoconductor 2Y, 2M, 2C, 2K, a charging member is used so that the photoconductor is charged, exposed, developed, transferred to an intermediate transfer medium, and toner remaining on the photoconductor is sequentially removed. 3Y, 3M, 3C, 3K, exposure devices 4Y, 4M, 4C, 4K, developing devices 5Y, 5M, 5C, 5K, squeeze means 7Y for removing carrier liquid in the liquid developer excessively attached to the surface of the photoreceptor , 7M, 7C, 7K, transfer devices 10Y, 10M, 10C, 10K to the intermediate transfer medium, and photosensitive member cleaning devices 9Y, 9M, 9C, 9K, which are latent image carrier cleaning devices.

  Further, the image forming apparatus 1 includes an endless intermediate transfer belt 18 that is an intermediate transfer medium. The intermediate transfer belt 18 is stretched around drive rollers 12A and 12B and driven rollers 13A and 13B that are arranged apart from each other, and is provided to be able to rotate counterclockwise in FIG. The intermediate transfer belt 18 is preferably an elastic intermediate transfer belt in order to improve the transfer efficiency of the transfer of the toner image onto the transfer material 14 such as paper.

A transfer device 19 from the intermediate transfer belt 18 is provided on the drive rollers 12A and 12B side of the intermediate transfer belt 18, and an intermediate transfer belt cleaning device 17 is provided on the driven roller 13A side of the intermediate transfer belt 18.
Further, in the transfer device 19, two backup rollers 20A and 20B are provided on the two drive rollers 12A and 12B, respectively, and transfer efficiency can be improved by transfer using two sets of rollers.

  Further, the transfer device 19 has a backup roller nip opening device 21 that can separate the backup rollers 20A and 20B and the intermediate transfer belt to open the nip, and collects the dispersant on the intermediate transfer belt 18. When the portion to which the carrier liquid is applied as the liquid passes, the backup liquid nip opening device 21 can prevent the carrier liquid from adhering to the backup rollers 20A and 20B.

  Although not shown, the image forming apparatus 1 of this example includes a transfer material storage device that stores a transfer material such as paper in the transfer device 19 and a pair of registration rollers that are conveyed and supplied from the transfer material storage device to the transfer device 19. And. The image forming apparatus 1 also includes a fixing device for fixing an image of the transfer material discharged from the transfer device 19 to the transfer material, and a paper discharge tray.

 In the image forming apparatus 1 of this example, the photoreceptors 2Y, 2M, 2C, and 2K and the developing devices 5Y, 5M, 5C, and 5K are arranged in the order of colors of Y, M, C, and K in the order of development. However, the arrangement order of Y, M, C, and K of these colors can be arbitrarily set.

A bias voltage having the same polarity as the charging polarity of the liquid developer is applied to each charging member 3Y, 3M, 3C, 3K from a power supply device (not shown). The charging members 3Y, 3M, 3C, and 3K charge the corresponding photoreceptors 2Y, 2M, 2C, and 2K, respectively.
Further, each of the exposure devices 4Y, 4M, 4C, and 4K respectively has a laser beam irradiated from a laser scanning optical system or the like on the corresponding charged photoreceptors 2Y, 2M, 2C, and 2K, or an LED, an EL, and the like. An electrostatic latent image is formed by light emitted from light emitting elements arranged in a line.

  The developer containers 30Y, 30M, 30C, and 30K of the developing devices 5Y, 5M, 5C, and 5K are supplied with the developer prepared at a predetermined concentration from the toner preparation tanks 25Y, 25M, 25C, and 25K of the respective colors. The The toner preparation tanks 25Y, 25M, 25C, and 25K for the respective colors are supplied with the carrier liquid 41 from the carrier liquid storage tanks 40Y, 40M, 40C, and 40K, and the toners 51Y, 51M from the toner storage tanks 50Y, 50M, 50C, and 50K. , 51C, 51K are replenished.

The liquid developers are supplied to the anilox rollers 33Y, 33M, 33C, and 33K by the supply rollers 32Y, 32M, 32C, and 32K that rotate clockwise.
The anilox rollers 33Y, 33M, 33C, and 33K rotate counterclockwise, and the thickness of the supplied liquid developer is regulated by the regulating blades 34Y, 34M, 34C, and 34K, and the developing rollers 35Y and 35M are arranged. , 35C, 35K.

The developing rollers 35Y, 35M, 35C, and 35K are all rotated counterclockwise as indicated by arrows in FIG. 1, and are supplied with a developing bias by the charging members 36Y, 36M, 36C, and 36K. The electrostatic latent images formed in 2Y, 2M, 2C, and 2K are developed. Next, the liquid developer remaining on the corresponding developing rollers 35Y, 35M, 35C, and 35K is scraped off by the developing roller cleaners 37Y, 37M, 37C, and 37K formed of a member such as rubber that is in contact with the surface of each developing roller. To be removed.
In addition, excess carrier liquid contained in the developer image formed on the developing rollers 35Y, 35M, 35C, and 35K is collected by the squeeze rollers 7Y, 7M, 7C, and 7K, and the toner preparation tanks 25Y, 25Y, Sent to 25M, 25C, 25M.

  In the present invention, various types of liquid developers 31Y, 31M, 31C, and 31K stored in the developer containers 30Y, 30M, 30C, and 30K can be used. For example, Use 10 to 30% by weight of toner particles of about 0.1 to 5 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin, 10% by weight without a dispersing agent, and the remainder as a carrier liquid. Can do.

  As the carrier liquid, in the case of a low-viscosity low-concentration liquid developer, for example, an insulating carrier liquid such as Isopar (registered trademark), which is an isoparaffin-based organic solvent, can be used. In the case of the agent, for example, a silicone oil having a flash point of 210 ° C. or higher, such as phenylmethylsiloxane, dimethylpolysiloxane, and polydimethylcyclosiloxane, a mineral oil, and a relatively high viscosity of 3 mPa · s at a boiling point of 130 ° C. or higher and 40 ° C. Insulating carrier liquids such as aliphatic saturated hydrocarbons such as low-viscosity liquid paraffin, normal paraffins, vegetable oils and higher fatty acid esters can be used.

The dispersant is blended in order to improve the dispersibility of the toner in the carrier liquid, and a substance having an excellent affinity for both the toner and the carrier liquid is used. For example, a polymer having an acidic group, an amine group or the like in the chemical structure is used.
Examples of dispersants comprising polymers having acidic groups include polyacrylic acid and its hydrocarbon soluble copolymer, polymethacrylic acid and its hydrocarbon soluble copolymer, polystyrene sulfonic acid and its hydrocarbon soluble copolymer, Examples thereof include polyvinyl sulfonic acid and its hydrocarbon-soluble copolymer, styrene / maleic acid copolymer and its hydrocarbon-soluble derivative, vinyl methyl ether / maleic acid copolymer and its hydrocarbon-soluble derivative, and the like. The weight average molecular weight of these polymers is preferably 1,000 to 100,000.
Specifically, a hydrocarbon-soluble copolymer containing acrylic acid, methacrylic acid, or a mixture thereof (for example, trade name Solsperse 3000 (manufactured by Librezorb), trade name Solsuspulse 28000 (Solsperse28000) (manufactured by Libresorb)) Is mentioned.

Examples of the dispersant composed of a polymer having an amine group include polyvinylpyrrolidone, polyamine, polyethyleneimine, amine group-containing poly (meth) acrylate, amine group-containing alkyl (meth) acrylate and (meth) acrylate copolymer, and these And hydrocarbon-soluble derivatives of In addition, (meth) acrylate means what contains at least any one of an acrylate and a methacrylate.
Specifically, hydrocarbon soluble copolymers derived from tertiary amine monomers such as dimethylaminoethyl methacrylate. (For example, trade name Solsperse 13940 (manufactured by Librezob)) can be mentioned.
The viscosity of the liquid developer can be controlled by the structure and addition amount of the dispersant. The added amount of the dispersant is 0.01 to 20% by mass, preferably 0.1 to 10% by mass with respect to the liquid developer. By making the addition amount within this range, it is possible to avoid the occurrence of unevenness in the film thickness of the developer and to form a good image without unevenness in density.

  The toner images formed on the photoreceptors 2Y, 2M, 2C, and 2K are transferred to the intermediate transfer belt 18 by the transfer devices 10Y, 10M, 10C, and 10K. Each transfer device is provided with transfer backup rollers 15Y, 15M, 15C, and 15K for bringing the intermediate transfer belt 18 into contact with the photoreceptors 2Y, 2M, 2C, and 2K. Each backup roller 15Y, 15M, 15C, 15K is applied with a transfer bias of, for example, -200V to -400V having a polarity opposite to the charged polarity of the toner particles, and the developer on each of the photoreceptors 2Y, 2M, 2C, 2K. The image is transferred to the intermediate transfer belt 18.

  Each of the photoconductor cleaning devices 9Y, 9M, 9C, and 9K includes a photoconductor cleaner 91 and a photoconductor cleaner recovery liquid storage container 92. Each photoconductor cleaner 91 is made of an elastic material such as rubber, and abuts on the surface of each corresponding photoconductor 2Y, 2M, 2C, 2K and remains on each photoconductor 2Y, 2M, 2C, 2K. The developer is scraped off and removed. Further, the photoreceptor cleaner collection liquid storage container 92 collects and stores the developer scraped off from the photoreceptors 2Y, 2M, 2C, and 2K by the photoreceptor cleaner 91, respectively. Further, the developer stored in each of the photoconductor cleaning devices 9Y, 9M, 9C, and 9K is collected in the developer collection container 90.

The image forming apparatus 1 of the present invention has a dispersant recovery liquid application unit 6, and an application roller 65 provided in the dispersant recovery liquid application unit abuts on the intermediate transfer belt 18 to supply the dispersant recovery liquid 61. Apply. The dispersing agent recovery liquid coating means 6 can be disposed at a position where the coating roller contacts the intermediate transfer belt located upstream of the photosensitive member. However, as shown in FIG. It is preferable to provide on the opposite surface of the contact portion.
In this way, by arranging to contact the intermediate transfer belt 18 on the surface opposite to the contact portion of the driven roller, a dedicated member for bringing the application roller 65 into contact with the intermediate transfer belt 18 becomes unnecessary.

Further, the dispersant recovery liquid 61 is replenished from the dispersant recovery liquid storage tank 60 and adjusted to a predetermined thickness by the supply roller 63 and the regulating blade 64 in the dispersant recovery liquid container 62, and then the dispersant recovery liquid application roller 65. To be supplied. Further, the dispersant recovery liquid 61 dissolves and dilutes the dispersant remaining on the intermediate transfer belt 18. The liquid in which the dispersant is dissolved is removed by the intermediate transfer belt cleaning device 17 and sent to the developer recovery container 90.
As described above, when the dispersant recovery liquid applied on the intermediate transfer belt reaches the secondary transfer device 19, the backup roller nip opening device 21 provided in the secondary transfer device 19 is operated, It is possible to prevent the dispersant recovery liquid from adhering to the backup roller.

The dispersant recovery liquid 61 also moves from the intermediate transfer belt 18 side to the photoreceptors 2Y, 2M, 2C, and 2K in the transfer devices 10Y, 10M, 10C, and 10K.
Therefore, when the main purpose is to remove the dispersant remaining on the intermediate transfer belt 18, it is preferable to prevent the dispersion of the dispersant recovery liquid from the photoreceptors 2Y, 2M, 2C, and 2K. .
To prevent the transfer to each photoconductor 2Y, 2M, 2C, 2K, the nip between each photoconductor 2Y, 2M, 2C, 2K and the intermediate transfer belt in each transfer device 10Y, 10M, 10C, 10K is opened. That is, a method of separating the two can be mentioned. Further, by making the peripheral speed of the intermediate transfer belt faster than that at the time of image formation, the amount of transfer from the intermediate transfer belt 18 side to each of the photoreceptors 2Y, 2M, 2C, and 2K can be reduced.

  On the other hand, the dispersant recovery liquid 61 is positively transferred from the intermediate transfer belt 18 side to the photoreceptors 2Y, 2M, 2C, and 2K, thereby removing the dispersant from the intermediate transfer medium 18 and each photoreceptor 2Y. , 2M, 2C, 2K can be removed simultaneously.

FIG. 2 is a view for explaining the recovery mechanism of the dispersant of the image forming apparatus of the present invention.
FIG. 2A is a diagram for explaining the operation during development.
After the photosensitive member 2Y is charged by the charging member 3Y while rotating clockwise, it is exposed by the exposure device 4Y to form an electrostatic latent image.
Next, in the developing device 5Y, the carrier liquid 41 supplied from the carrier liquid storage tank 40Y and the toner 51Y supplied from the toner storage tank 50Y are prepared into a developer having a predetermined concentration in the developer preparation tank 25Y, and the developer container 30Y. To be supplied. The supplied liquid developer 31Y is supplied by the supply roller 32Y and the anilox roller 33Y, and the electrostatic latent image is developed by the developing roller 35Y.

Further, the developer image on the photoreceptor 2Y that has developed the electrostatic latent image is squeezed by the squeeze device 7Y to collect excess carrier liquid, and the collected developer is collected to the developer preparation tank 25Y. .
Next, the formed developer image is transferred on the intermediate transfer belt 18 as an intermediate transfer medium by being applied with a transfer bias by the backup roller 15Y in the transfer device 10Y, and transferred to a transfer material such as paper in the transfer device. The image is fixed by the fixing device and taken out from the image forming apparatus.

The residual developer 70 remaining on the photoconductor 2 after the transfer is removed by a photoconductor cleaner 91 provided in the photoconductor cleaning device 9Y, recovered in the photoconductor cleaner recovery liquid storage container 92, and then to the developer recovery container 90. Sent.
The solid component in the residual developer 70 is removed by the photoreceptor cleaning device 9Y.

Further, the residual developer 70 remaining on the intermediate transfer belt 18 after completion of the transfer from the intermediate transfer belt is removed by the intermediate transfer belt cleaning member 17A provided in the intermediate transfer belt cleaning device 17 and collected in the intermediate transfer belt cleaning container 17B. After that, it is sent to the developer recovery container 90.
The solid component in the residual developer 70 is removed by the intermediate transfer belt cleaning device 17, but the dispersant dissolved in the carrier liquid is completely removed by the intermediate transfer belt cleaning member 17 </ b> A provided in the intermediate transfer belt cleaning device 17. Instead, it remains as a residual liquid 72 containing a dispersant on the surface of the intermediate transfer belt 18.

On the other hand, in the image forming apparatus of the present invention, as shown in FIG. 2B, after the developing device 5Y develops the electrostatic latent image on the photoreceptor 2Y, it is provided in the dispersant recovery liquid coating unit 6. The dispersant recovery liquid 61 is applied from the application roller 65 to the intermediate transfer belt 18.
The dispersant in the residual liquid 72 on the intermediate transfer belt 18 is dissolved in the applied dispersant recovery liquid 61 and further dissolved and diluted with the dispersant recovery liquid to form a dispersant liquid dilution layer 74.

  As the intermediate transfer belt 18 rotates, the dispersant dilution layer 74 reaches the intermediate transfer belt cleaning device 17, is removed by the intermediate transfer belt cleaning member 17A, and is collected in the intermediate transfer belt cleaning container 17B, and then the developer collection container. Recovered to 90.

  When the application of the dispersant recovery liquid to the intermediate transfer belt and the dispersant recovery process are completed, a development process is executed as shown in FIG.

  As described above, high-quality image formation can be performed by repeating the development process shown in FIG. 2A and the dispersant recovery process shown in FIG. The dispersant recovery process may be performed alternately with the development process, but may be performed once for a plurality of development processes, or may be performed at the start or end of the development process.

FIG. 3 is a view for explaining the positional relationship of the application part of the dispersant in the image forming apparatus of the present invention.
3A shows a distance L1 between the coating roller 65 of the dispersant recovery liquid coating unit 6 and the nip portion of the primary transfer portion 10, and the nip of the transfer portion 10 from the exposure device 4Y of the photoreceptor 2Y to the intermediate transfer belt. FIG. 6 is a diagram illustrating a relationship of a distance L2 between parts, and illustrates a state in which an electrostatic latent image at a position corresponding to the rear end of a printable area when an image is formed for each page is formed on the photoreceptor 2Y.
That is, L2 indicates the distance from the nip portion of the transfer device 10Y to the intermediate transfer belt to the rear end of the image when the rear end position of the electrostatic latent image corresponding to the rear end of the image is exposed.
On the other hand, L1 represents the distance from the application roller 65 to the nip portion.

  Therefore, the relationship of L1> L2 is set so that the portion where the dispersant recovery liquid is applied does not overlap the position corresponding to the rear end of the image on the intermediate transfer belt 18, and the dispersant is placed on the intermediate transfer belt 18. It becomes possible to apply the dispersant recovery liquid without increasing the length of the portion where the recovery liquid is not applied.

FIG. 3B shows an image rear end position A of the developer image made of the developer 31Y formed on the photoreceptor 2Y in the image transfer end 10 on the intermediate transfer belt 18 in the transfer device 10 to the intermediate transfer belt. In contrast to the transfer to B, the application portion tip position C of the dispersant recovery liquid 61 is located slightly behind B.
That is, from the position C upstream of the image forming position B on the rotatable intermediate transfer belt 18 on which the developer image on the photoreceptor 2Y to which the image is first transferred to the intermediate transfer medium 18 is transferred. In the drawing, it is shown that the dispersion recovery liquid application roller 65 of the application unit 6 controls to start application of the dispersion liquid that can dissolve the dispersion in the liquid developer.

FIG. 4 is a diagram illustrating a control method in the image forming apparatus of the present invention.
FIG. 4A shows an example in which the exposure operation is ended at t2 after the application operation of the dispersant recovery liquid is started at t1.
For example, under the following conditions, the trailing edge of the print image needs to pass through the transfer nip before the leading edge of the application part of the dispersant recovery liquid reaches the transfer nip to the intermediate transfer belt. The difference requires 0.7 seconds.
Printing speed A4 paper 40 sheets per minute 214mm / sec 140mm distance between coating roller and transfer nip to intermediate transfer medium
Distance between exposed area and primary transfer area 125.6mm

  FIG. 4B shows the nip between the transfer roller to the transfer material and the intermediate transfer belt, and after the passage of t4 through which the rear end of the image passes, the nip between the transfer roller to the transfer material and the intermediate transfer belt at t5. It shows opening. Furthermore, even after the tip of the application part of the dispersant recovery liquid has passed at t6, the application part of the dispersant recovery liquid remains open until the end of passing, and after the application part of the dispersant recovery liquid has passed, A predetermined nip is established when a predetermined time has elapsed.

  FIG. 4C is a diagram for explaining a photosensitive member-intermediate transfer belt nip opening time point t3 in the transfer portion to the intermediate transfer belt, where t3 is an intermediate transfer medium from the application start time t1 of the dispersant recovery liquid. The time is set to be shorter than the time obtained by adding the time before the tip of the application part of the dispersant recovery liquid reaches the transfer nip.

FIG. 4D shows the state in which the photoconductor and the intermediate transfer belt are in contact with each other, and the photoconductor and the intermediate transfer belt are rotated after the photoconductor at the final stage is rotated for t3 or more to which the dispersant recovery liquid is applied. It shows that the nip with the transfer belt is opened, and further, the recovery liquid for one round of the belt is applied to the intermediate transfer belt until t7.
As a result, it is possible to perform a cleaning process in which the intermediate transfer belt is cleaned by applying the dispersant recovery liquid to the photoreceptor and the subsequent application of the dispersant recovery liquid to the belt.

FIG. 5 is a diagram for explaining another embodiment of the image forming apparatus according to the present invention.
In the image forming apparatus 1 described with reference to FIG. 1, the intermediate transfer belt 18 is stretched around drive rollers 12A and 12B and driven rollers 13A and 13B that are spaced apart from each other, and can rotate counterclockwise in FIG. 5 is different from that shown in FIG. 5 in that it is stretched around the driving roller 12 and the driven roller 13 so as to be rotatable counterclockwise in FIG. The image is formed in the same manner as the image forming apparatus shown in FIG.

FIG. 6 is a diagram for explaining another embodiment of the image forming apparatus according to the present invention.
It is a figure explaining the image forming apparatus which supplies a carrier liquid as a dispersing agent collection | recovery liquid to an application | coating means, dissolves, dilutes, and separates a dispersing agent.
1 is different from the image forming apparatus shown in FIG. 1 in that the carrier liquid 41 supplied from the carrier liquid storage tank 40Y provided for the preparation of the liquid developer is used as the dispersant recovery liquid.
In the image forming apparatus 1, as in the first embodiment, the photoconductors 2Y, 2M, 2C, and 2K are arranged in a tandem type, and carrier liquid application means 7 provided as a dispersant recovery liquid application means. The application roller 45 comes into contact with the intermediate transfer belt 18 to apply the carrier liquid 41 as a dispersant recovery liquid.

  Further, the carrier liquid 41 is supplied from the carrier liquid storage tank 40Y to a predetermined thickness by the supply roller 43 and the regulating blade 44 in the carrier liquid container 42, and then supplied to the carrier liquid application roller 45.

  The carrier liquid 41 applied to the intermediate transfer belt 18 by the carrier liquid application roller 45 forms a dispersant dilution layer in which the dispersant remaining on the intermediate transfer belt is diluted.

The dispersant diluted layer reaches the intermediate transfer belt cleaning device 17 and is removed by the intermediate transfer belt cleaning member 17A. After being recovered in the intermediate transfer belt cleaning container 17B, it is sent to the developer recovery container 90.
As shown in FIG. 6, since the carrier liquid prepared for the preparation of the liquid developer is used, it is necessary to prepare a carrier liquid for collecting the dispersant separately from the carrier liquid for preparing the liquid developer. There is no.

FIG. 7 is a diagram for explaining another embodiment of the image forming apparatus according to the present invention.
In the image forming apparatus 1 described with reference to FIG. 6, the intermediate transfer belt 18 is stretched around driving rollers 12A and 12B and driven rollers 13A and 13B that are arranged apart from each other, and can rotate counterclockwise in FIG. 7 is different from that shown in FIG. 7 in that it is stretched around the driving roller 12 and the driven roller 13 and can be rotated counterclockwise in FIG. However, the image is formed in the same manner as the image forming apparatus shown in FIG.

FIG. 8 is a diagram for explaining another embodiment of the image forming apparatus according to the present invention.
The image forming apparatus shown in FIG. 8 uses the carrier liquid 41 supplied from the common carrier liquid storage tank 40 for the dispersant recovery liquid and the carrier liquid for preparing liquid developers of the respective colors, as shown in FIG. Is different.
From the carrier liquid storage tank 40, the carrier liquid is supplied to the dispersant recovery liquid coating means 6 and applied to the surface of the intermediate transfer belt 18, and to the liquid developer preparation tanks 25Y, 25M, 25C, and 25K for the respective colors. It is characterized in that it is supplied and mixed with toner and used to prepare a liquid developer having a predetermined concentration.
The image forming apparatus of FIG. 8 has a feature that it is not necessary to separately prepare a dispersant recovery liquid or to prepare a carrier liquid for each color.

FIG. 1 is a diagram partially showing an example of an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a view for explaining the recovery mechanism of the dispersant of the image forming apparatus of the present invention. FIG. 3 is a view for explaining the positional relationship of the application part of the dispersant in the image forming apparatus of the present invention. FIG. 4 is a diagram illustrating a control method in the image forming apparatus of the present invention. FIG. 5 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention. FIG. 6 is a diagram for explaining an embodiment of an image forming apparatus according to the present invention. FIG. 7 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention. FIG. 8 is a diagram for explaining an embodiment of an image forming apparatus according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2Y, 2M, 2C, 2K ... Photosensitive body of each color, 5Y, 5M, 5C, 5K ... Developing apparatus of each color, 6 ... Dispersing agent recovery liquid applying means, 7 ... Carrier liquid applying means, 10Y, 10M, 10C, 10K: Transfer device to intermediate transfer medium, 9Y, 9M, 9C, 9K ... Photoconductor cleaning device, 14 ... Transfer material, 15Y, 15M, 15C, 15K ... Backup roller, 17 ... Intermediate transfer belt cleaning device , 18 ... Intermediate transfer belt, 19 ... Transfer device to transfer material, 25Y, 25M, 25C, 25K ... Liquid developer preparation tank, 31Y, 31M, 31C, 31K ... Liquid developer, 35Y, 35M, 35C, 35K ... Developing roller 41 ... Carrier liquid, 42Y, 45M, 45C, 45K ... Carrier liquid application roller, 60 ... Dispersing agent recovery liquid storage tank, 61 ... Dispersing agent recovery liquid, 65 ... Dispersing agent recovery liquid application roller, 90 ... Developing liquid times Container, 70 ... residual developer, 74 ... dispersing agent solution diluted layer

Claims (7)

A latent image carrier;
A developing device that develops a liquid developer containing toner, carrier liquid, and a dispersant soluble in the carrier liquid onto the latent image carrier;
An intermediate transfer medium onto which the developer image developed on the latent image carrier is transferred;
A transfer device for transferring the developer image on the intermediate transfer medium to a transfer material;
A dispersant recovery liquid applying means for applying a dispersant recovery liquid on the intermediate transfer medium,
The image forming is characterized in that after the transfer of the developer image onto the intermediate transfer medium is completed, the application of the dispersant recovery liquid is controlled to start on the intermediate transfer medium by the application means of the dispersant recovery liquid. Device control method.   After the developer image is transferred onto the intermediate transfer medium, the transfer roller of the transfer device is moved until the start of application of the dispersant recovery liquid onto the intermediate transfer medium by the dispersant recovery liquid application unit. 2. The method of controlling an image forming apparatus according to claim 1, wherein the control is performed so as to be separated from the intermediate transfer medium.   3. The method of controlling an image forming apparatus according to claim 2, wherein the separation of the transfer roller continues until the end of the operation of removing the dispersant by applying the dispersant recovery liquid.   After the transfer from the latent image carrier to the intermediate transfer medium is completed, the rotation speed of the intermediate transfer medium is set to rotate the intermediate transfer medium when the developer image is transferred from the latent image carrier to the intermediate transfer medium. 4. The method for controlling an image forming apparatus according to claim 1, wherein the speed is higher than the speed.   Before the coating start position on the intermediate transfer medium of the dispersant recovery liquid applied by the dispersant recovery liquid application means reaches the transfer portion for transferring the intermediate transfer medium developer image from the latent image carrier, 4. The method for controlling an image forming apparatus according to claim 1, wherein the latent image carrier is separated from the intermediate transfer medium.   After the latent image carrier and the intermediate transfer medium are in contact with each other, the latent image carrier and the intermediate transfer medium are rotated after being rotated until the dispersion liquid is applied to the latent image carrier for one round or more. 2. The method of controlling an image forming apparatus according to claim 1, wherein the intermediate transfer medium is rotated at least once around the intermediate transfer medium to disperse the dispersion recovery liquid onto the intermediate transfer medium. . A latent image carrier;
A rotatable developing roller for transporting a liquid developer containing a toner for developing an electrostatic latent image, a carrier liquid, and a dispersant soluble in the carrier liquid develops the latent image on the latent image carrier. A developing device,
A rotatable intermediate transfer medium onto which the developer image on the latent image carrier is transferred;
An intermediate transfer medium cleaning device for cleaning the intermediate transfer medium;
Coating means for applying a dispersant recovery liquid on the intermediate transfer medium;
An image forming apparatus comprising:

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