JP2000029322A - Liquid developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developing device capable of reducing futile liquid toner. SOLUTION: The liquid developing device is provided with plural developer scraping cleaning blades 50ar, 50br, 50cr, 50al, 50bl and 50cl for dividing/ removing a thin layer region except the region width of an electrostatic latent image formed on a photoreceptor, in the region width of a thin layer of liquid toner formed on an application roller 45, a coating roller 46 or a developing belt 41 and a CPU 55 for selecting the developer scraping cleaning blades 50ar, 50br, 50cr, 50al, 50bl and 50cl, so as to obtain correspondence to the region width of the electrostatic latent image formed on the photoreceptor. Thus, the thin layer region width of a developer is made variable according to a change in an image writing region and the futile liquid toner can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developing apparatus, and more particularly, to a liquid developing apparatus that visualizes an electrostatic latent image formed by an electrophotographic method or the like using a high-viscosity, high-density liquid developer. .

[0002]

2. Description of the Related Art An image forming apparatus for visualizing an electrostatic latent image formed by an electrophotographic method or the like using a high-viscosity, high-density liquid developer is disclosed in, for example, JP-A-7-209922. I have.

FIG. 4 is a sectional view showing the structure of a wet image forming apparatus using a conventional liquid developing device. As shown in the figure, the conventional wet image forming apparatus includes a charging unit 2, an exposure unit 3, a liquid developing device 4, a paper supply unit 5, a paper supply unit 7, a resist 8, a transfer unit 9, , Static elimination means 10
, A cleaning unit 11, a fixing unit 12, and a paper discharge unit 13. The charging unit 2, the exposing unit 3, the liquid developing unit 4, the transferring unit 9, the discharging unit 10, and the cleaning unit 11 are arranged along the photoconductor 1 rotating clockwise. The surface of the photoconductor 1 is uniformly charged by the charging unit 2. Exposure means 3 is provided on the surface of the charged photoconductor 1.
As a result, an electrostatic latent image exposed according to image data is formed. The electrostatic latent image formed on the photoconductor 1 is visualized as a toner image by the liquid developing device 4. This toner image is set in the paper feeding unit 5 and is
The photoconductor 1 is picked up one by one and
Transfer means 9 on the transfer paper 6 conveyed between the
And the toner image transferred to the transfer paper 6 is fixed by the fixing unit 12. The transfer paper 6 after the fixing process is discharged to the paper discharge unit 13. Then, the charge remaining on the photoreceptor 1 is discharged by the discharging unit 10, and the remaining toner is removed by the cleaning unit 11 to start the next image forming process.

Next, the liquid developing device 4 in the conventional wet image forming apparatus will be described. This liquid developing device 4
Is a high-viscosity liquid developer of 100 to 10000 mPa · s in which a liquid toner as visualized particles is dispersed at a high concentration in a developer solvent made of an insulating liquid such as dimethylpolysiloxane oil. A developing belt 41 wound around a plurality of rotating rollers 41a to 41d and moving counterclockwise at the same surface moving speed as the surface moving speed of the photoconductor 1, and an application roller 45
, A squeeze roller 47, a belt cleaning unit 48, and a waste toner tank 49. Application roller 45 and application roller 4
6 and the squeeze roller 47 uniformly apply the liquid toner 43, which is stored in the developer storage section 44 and has an optimal ratio of the toner to the developer medium to form an image having an optimum image density, on the developing belt 41. This is a roller for forming a thin liquid developer layer having a thickness. The belt cleaning unit 48 removes liquid toner remaining on the developing belt 41 that has passed through the developing area. The waste toner tank 49 stores liquid toner which is removed by the belt cleaning means 48 and discarded. The rotating roller 41d has a developing bias means 42 for applying a potential between the minimum value and the maximum value of the latent image potential on the photoconductor 1.

Next, the operation of the conventional liquid developing device 4 configured as described above will be described. In the conventional liquid developing device 4, the electrostatic latent image formed on the photoconductor 1 is developed and visualized. At this time, a liquid developing thin layer having a uniform thickness of the liquid toner 43 is formed by the application roller 45, the application roller 46, and the squeeze roller 47 on the developing belt 41 rotating counterclockwise. The electrostatic latent image on the photoconductor 1 is visualized with the toner contained in the liquid developing thin layer having a uniform thickness formed on the developing belt 41. When the electrostatic latent image on the photoconductor 1 is visualized in this manner, the liquid toner 43 adheres only to the image portion of the electrostatic latent image, and the developer solvent as a carrier adheres to the entire area of the photoconductor 1. . The liquid toner 43 remaining on the developing belt 41 after the developing process is removed by a belt cleaning unit 48 and stored in a waste toner tank 49.

[0006]

However, in the above conventional example, even when the image writing area is changed, for example, when the image area signal is changed from an A3 size width image to a postcard size, the A3 size width is changed. As it is, a thin layer is formed by the application roller, squeeze roller, or coating roller, and when development is performed in that state, the liquid toner in only the postcard size image area on the development belt visualizes the latent image on the photoconductor And the liquid toner on the developing belt applied to the area other than the postcard size is collected as waste toner by a belt cleaning unit in a waste toner tank and discarded, resulting in wasteful consumption of the liquid toner. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and a liquid developing device capable of reducing the useless liquid toner by making the width of the thin layer region of the developer variable according to the change of the image writing region. It is intended to provide a device.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a developer support for visualizing an electrostatic latent image formed on a latent image carrier, and a developer support on a surface of the developer support. A developer supply means for moving the liquid developer from the liquid developer storage to the developer support to form a thin layer of the liquid developer; and supplying the liquid developer to the developer support. Of the area width of the thin layer of liquid developer
A plurality of removing means for dividing and removing a thin layer region other than the region width of the electrostatic latent image formed on the latent image carrier, and corresponding to the region width of the electrostatic latent image formed on the latent image carrier; Selecting means for selecting the removing means as described above. Therefore, the width of the thin layer region of the developer can be changed according to the change of the image writing region, and the useless liquid toner can be reduced.

Further, a plurality of removing means are provided on the developer supply means or the developer support. Further, when the removing unit is a blade, each blade is installed in parallel with a direction orthogonal to the moving direction of the developer supply unit or the developer support.
Alternatively, each blade is arranged at a predetermined angle with respect to a direction perpendicular to the moving direction of the developer supply means or the developer support. Therefore, since the blades can be shared and wear of the blades can be reduced, cost reduction in manufacturing and running can be achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing belt for visualizing an electrostatic latent image formed on a photoreceptor, and a developing belt for supplying a liquid toner from a liquid developer storage unit to form a thin layer of the liquid toner on the surface of the developing belt. In a liquid developing device having at least an application roller and an application roller that move to and supply the electrostatic latent image formed on the photoreceptor within a thin layer area width of the liquid toner formed on the application roller or the application roller A plurality of developer scraping cleaning blades for dividing and removing a thin layer area other than the area width of the area, and a developing blade scraping cleaning blade corresponding to the area width of the electrostatic latent image formed on the photoconductor. And a CPU for selecting. Therefore, the width of the thin layer region of the developer can be changed according to the change of the image writing region, and the useless liquid toner can be reduced.

Further, each developer scraping cleaning blade is installed in parallel with the direction of the axis of the application roller or the application roller. Alternatively, each developer scraping cleaning blade is arranged at a predetermined angle with respect to the axis of the application roller or the application roller. Therefore, the cost can be reduced in manufacturing and running by using the same cleaning blade for each developer scraping and reducing the wear of each cleaning blade for developer scraping.

[0012]

FIG. 1 is a sectional view showing the structure of a liquid developing apparatus according to an embodiment of the present invention. 4, the same reference numerals as those in FIG. 4 denote the same components. As shown in the figure, the liquid developing device 4 of this embodiment includes a developing belt 41, a developer storage section 44, an application roller 45, an application roller 46, a squeeze roller 47, a belt cleaning unit 48, The cleaning blades 50ar, 50br, 50cr, 50al, 50bl for scraping the developer,
50cl, solenoids 51a, 51b, 51c, solenoid drivers 52a, 521b, 52c, springs 53ar, 53br, 53cr, 53al, 53b.
1, 53cl and a roller drive motor 54.

The developing belt 41 is rotated by rotating rollers (rotating rollers 41a, 41b, 41c, 41d (see FIG. 4)) between a developing roller 41 and a coating surface of a photosensitive member (not shown). Move. Liquid toner is stored in the developer storage section 44. Application roller 4
5 and the application roller 46 and the squeeze roller 47 supply the developing belt 41 with the liquid toner, which is stored in the developer storage section 44 and has an optimally adjusted ratio of the toner to the developing medium in order to form an image having an optimum image density. The roller is a roller for forming a liquid developer thin layer having a uniform thickness, and is rotated by a roller drive motor 54. A developer scraping cleaning blade 50ar, 50al, a developer scraping cleaning blade 50br, 50bl,
Cleaning blades 50cr, 50 for scraping developer
cl are provided on the left and right sides of the center portion, respectively, and springs 53ar, 53br, 53c fixed at one end are provided.
Each of r, 53al, 53bl, and 53cl is in contact with the surface of the application roller 45.
Further, in order to prevent streaks occurring in the thin layer forming area when there is a gap between the adjacent developer scraping cleaning blades, one end of the adjacent developer scraping cleaning blade is perpendicular to the axis of the application roller 45. They are arranged to overlap each other. Solenoid 5
1a, 51b, and 51c are solenoid drivers 52a, 52a to which drive control signals from a CPU 55 described later are supplied.
By applying voltages from 21b and 52c, the developer scraping cleaning blades 50ar and 50al, the developer scraping cleaning blades 50br and 50bl, and the developer scraping cleaning blades 50cr and 5cr, respectively.
0cl to springs 53ar, 53br, 53cr, 5
Suction is performed against the respective spring forces of 3al, 53bl, and 53cl. Thus, the suctioned cleaning blade for scraping the developer is applied to the application roller 45.
Is released from contact with the surface of the application roller 45.
Will be separated from the surface.

The width La of the thin layer forming area is obtained by bringing all the developer scraping cleaning blades into contact with the application roller 45. That is, no voltage is applied to any of the solenoids 51a, 51b, and 51c from the solenoid drivers 52a, 521b, and 52c by a drive control signal from the CPU 55 described later. Furthermore, the thin layer formation region width Lb
Are developer cleaning blades 50ar,
The cleaning blade other than 50al is brought into contact with the application roller 45. That is, a voltage is applied only to the solenoid 51a from the solenoid driver 52a based on a drive control signal from the CPU 55 described later. Further, the width Lc of the thin layer forming region is determined by the cleaning blade 50c for scraping the developer.
Only r and 50 cl are obtained by contacting the application roller 45. That is,
Solenoid drivers 52a and 52b are supplied to the solenoids 51a and 51b by drive control signals from a CPU 55 described later.
A voltage is applied from b.

Further, the liquid developing device 4 of this embodiment has an I / O
It is controlled by a printer engine including a CPU 55 with O, ROM 56, and RAM 57. This CPU 55
Outputs an image data request signal to a printer controller (not shown) via a buffer circuit, and receives a print start signal and image area designation data such as a paper size designation signal from the printer controller via the buffer circuit. Then, the CPU 55 selects a desired developer scraping cleaning blade based on the input information thus input and the thin layer forming width data corresponding to the sheet size stored in the ROM 56, and selects the selected developer scraping blade. A drive control signal is output to a solenoid driver that applies a voltage to a solenoid that sucks the cleaning blade. The RAM 57 stores printer information including print paper size information for determining a print area.

Next, the operation of the liquid developing apparatus 4 of the present embodiment will be described below with reference to FIG. 1 and FIG. 2 showing an operation flow.

First, when the power of the printer is turned on (S
1) The CPU 55 controls the solenoid drivers 52a, 52b, 52 to set the thin layer forming area width La as a reference.
The voltage from c is not applied to the solenoids 51a, 51b, 51c (S2). Then, the CPU 55 waits for reception of image area designation data indicating printing conditions such as a print start signal and a print size designation signal from the printer controller. Thereafter, when a print start signal and image area designation data are supplied from the printer controller, the CPU 55 stores the image area designation data in the RAM.
57 is temporarily stored (S3). Then, the CPU 55
The selection data of the cleaning blade for developer scraping corresponding to the image area designation data stored in the AM 57 and corresponding to the thin layer forming area width data corresponding to the sheet size is RO.
Read from M56 (S4). Then, the CPU 55
A voltage is applied to the solenoid driver to the solenoid that sucks the corresponding developer scraping cleaning blade based on the selection data of the developer scraping cleaning blade read from the OM 56 (S5). For example, when printing is performed on the thin layer forming area width Lc, the solenoid drivers 52a and 52b are driven by a drive control signal from the CPU 55.
Is applied to the solenoids 51a, 51b, and the developer scraping cleaning blades 50cr, 50cl are applied.
Only the application roller 45 comes into contact with the application roller 45.

After that, the CPU 55 transmits an image data request signal to the printer controller and enters a state of waiting for image data. Then, when receiving the image data corresponding to the image data request signal (S6), the CPU 55 turns on the roller drive motor 54 to rotate the application roller 45, the application roller 46, and the squeeze roller 47 (S7). In the liquid developing device 4, the application roller 45 and the squeeze roller 47 are rotated while applying the liquid toner stored in the developer storage unit 44 to the surface of the application roller 45 (S8). A thin layer of the liquid toner applied is formed on the surface of the application roller 45 (S9). Then, the printer controller sends the image data in accordance with the image data request signal from the CPU 55 to the exposure means 3 shown in FIG.
(S10) to form an electrostatic latent image on the photoreceptor 1.
A thin layer of toner is applied to the area of the electrostatic latent image on photoreceptor 1 to visualize the electrostatic latent image on photoreceptor 1. The visualized image on the photoreceptor 1 is transferred to the transfer paper 6 fed from the paper supply unit 5 by the transfer means 9 (S11) and subjected to a fixing process by the fixing means 12 (S12). It is discharged to the unit 13 (S13). The liquid toner remaining on the developing belt 41 after the developing process is removed by the belt cleaning shaker 48, and is collected and stored in the developer storage unit 44 (S14).

In the above embodiment, the desired thin layer forming region width is formed by a pair of cleaning blades for scraping the developer with the center portion interposed therebetween.
The present invention is not limited to this, and can be formed by selecting an arbitrary developer cleaning blade. Further, in the above embodiment, the width of the image writing area and the width of the thin layer forming area are equal. However, it is not necessary to make them equal. If it is larger than the area width, the image will not be lost. Further, the present embodiment is an example in which the developer scraping cleaning blade is in contact with the application roller, but the developer scraping cleaning blade is in contact with the application roller, the developing belt, or the developing roller. It is needless to say that the same effect can be obtained by providing the same.

Here, the arrangement of the cleaning blade for scraping the developer will be described with reference to FIG. 3 showing an example of the arrangement of the cleaning blade for scraping the developer. The arrangement of the cleaning blades for developer scraping shown in FIG. 3A is provided on each of the left and right sides of the reference line of the center portion, and each cleaning blade for developer scraping rotates in the illustrated rotation direction. Application roller 45
Are arranged in parallel to the axis. In this arrangement, all the cleaning blades for scraping off the developer can be made to have the same shape, so that the parts can be unified and the production cost can be reduced. The arrangement of the cleaning blades for scraping off the developer shown in FIG. 3B is the same as that of FIG. 3A with respect to the arrangement position. They are arranged with a parallel line to the core at an angle θ. Here, it is assumed that the blade line of the cleaning blade for scraping off the developer forms a curve in order to come into contact with the peripheral surface of the application roller. Note that the angle θ may be changed for each developer scraping cleaning blade. In this way, by giving each developer scraping cleaning blade an angle θ, it is possible to scrape efficiently and further reduce the wear of the blade part, and thus the lining cost associated with reducing the frequency of component replacement. Can be suppressed. Further, the arrangement of the cleaning blade for scraping off the developer shown in FIG. 3C is such that the width of the thin layer forming area La,
The cleaning blades for scraping the developer are arranged parallel to the axis of the application roller 45 with Lb and Lc placed. In this case, FIGS. 3A and 3B
The number of cleaning blades for scraping the developer may be half. Therefore, the number of parts can be reduced, and the cost of the entire apparatus can be reduced. In addition, when the rotation direction of the application roller 45 is opposite to the rotation direction of the application roller 45 shown in FIG.
In the case of the arrangement shown in (1), the scraped liquid toner concentrates on the center portion, which is the application area, and an inconvenient supply of an inappropriate application amount occurs. Therefore, the rotation direction of the application roller 45 is preferably the illustrated direction.

In the above-described embodiment, the operation of changing the width of the thin layer region is performed during the printing operation and the image is transferred onto the transfer paper. In this case, the image may be disturbed or chipped. Therefore, the variable operation of the thin layer region forming width is performed before the printing is started, and the transfer paper is made to wait in front of the resist until the variable layer forming width variable operation is completed, or the variable operation of the thin layer region forming width is performed. The transfer of the transfer paper is stopped until the transfer is completed. As a result, information such as the size of the transfer paper is not cleared, and the operation control of the moving means for changing the area of the thin layer can be reliably performed without making the reference installation position unclear. Chipping can be prevented.

Further, normally, when the power of the printer or the like is turned off, all the printer information stored in the RAM of the printer is cleared. Naturally, the printer information also includes information on the paper size for determining the print area. Therefore, if the information on the paper size is cleared, the reference installation position in the above embodiment becomes unknown. Therefore,
In the present invention, when the power is turned on, the cleaning blade for scraping off the developer is once set to the reference installation position. Therefore, the operation control of the means for changing the area of the thin layer can be reliably performed without making the reference installation position unknown.

Further, in order to adapt the liquid developing apparatus of the present invention to a color or monocolor image forming apparatus, the liquid developing apparatus can be realized by providing a thin layer region forming width variable mechanism for each color developing unit.

It should be noted that the present invention is not limited to the above-described embodiment, and that various modifications and substitutions can be made within the scope of the claims.

[0025]

As described above, according to the present invention,
A plurality of removing means for dividing and removing a thin layer area other than the area width of the electrostatic latent image formed on the latent image carrier among the area widths of the thin layer of the liquid developer formed in the developer supply means. And selecting means for selecting the removing means so as to correspond to the area width of the electrostatic latent image formed on the latent image carrier, so that the width of the thin layer area of the developer can be changed in the image writing area. The amount of liquid toner can be reduced accordingly.

Further, a plurality of removing means are provided on the developer supply means or the developer support. Further, when the removing means is a blade, each blade is shared by installing each blade parallel or at a predetermined angle to a direction orthogonal to the moving direction of the developer supply means or the developer support. And by reducing blade wear,
Cost reduction in manufacturing and running can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a configuration of a liquid developing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the liquid developing device according to one embodiment of the present invention.

FIG. 3 is a view showing an example of an arrangement of a cleaning blade for scraping a developer of FIG. 1;

FIG. 4 is a cross-sectional view illustrating a configuration of a wet image forming apparatus using a conventional liquid developing device.

[Explanation of symbols]

50ar, 50br, 50cr, 50al, 50bl,
50cl Cleaning blade 55 for scraping developer
CPU

Claims (7)

[Claims] 1. A developer support for visualizing an electrostatic latent image formed on a latent image carrier, and a liquid developer for forming a thin layer of the liquid developer on a surface of the developer support. A developer supply means for moving the developer from the developer storage section to the developer support, and supplying the developer to the developer support. A plurality of removing means for dividing and removing a thin layer area other than the area width of the latent image; and selecting means for selecting the removing means so as to correspond to the area width of the electrostatic latent image formed on the latent image carrier. A liquid developing device comprising: 2. The liquid developing apparatus according to claim 1, wherein the plurality of removing units are provided in the developer supply unit. 3. The liquid developing apparatus according to claim 1, wherein said plurality of removing means are provided on said developer support. 4. The liquid developing apparatus according to claim 1, wherein the removing unit is a blade, and each blade is installed in parallel with a direction orthogonal to a moving direction of the developer supply unit. 5. The apparatus according to claim 1, wherein said removing means is a blade, and each blade is arranged at a predetermined angle with respect to a direction orthogonal to a moving direction of said developer supply means.
The liquid developing device according to item 1. 6. The liquid developing apparatus according to claim 1, wherein the removing unit is a blade, and each blade is installed in parallel with a direction orthogonal to a moving direction of the developer support. 7. The liquid according to claim 1, wherein the removing unit is a blade, and each blade is arranged at a predetermined angle with respect to a direction orthogonal to a moving direction of the developer support. Developing device.