JP2001350345A - Squeeze mechanism in liquid developing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a squeeze mechanism in a liquid developing system capable of removing toner shifting and adhering to a squeeze roller from a photoreceptor. SOLUTION: A solvent is supplied from a solvent channel 108 into a rear wall 110 provided on a withdrawing side from the contact part 106 of the squeeze roller 103 with a photoreceptor belt 101. Nine exit-side electrodes P1 to P9 are embedded in the wall 110. Voltage is applied to the electrodes P1 to P9 by a transfer voltage generation circuit 121 so that they may successively move in the rotating direction of the roller 103. Toner passing through the contact part 106 is electrophoresed in the solvent by the voltage applied to the electrodes P1 to P9, fed to a liquid reservoir 111 provided on the lower side of the roller 103 by the movement of the electrodes P1 to P9 to which the voltage is applied, and then discharged from a drain port 113 connected to the reservoir 111.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeezing mechanism of a liquid developing system, and relates to a solvent after development in an electrophotographic apparatus of a liquid developing system which is one of printing systems for forming an ultra-high-definition image or a color image. The present invention relates to a squeeze mechanism of a liquid developing system in which a squeeze roller is pressed against a photoconductor to squeeze and recover a solvent used for liquid development from the photoconductor in order to remove only a solvent from a painted image.

[0002]

2. Description of the Related Art In image formation by a liquid developing method, basically, toner is electrostatically adsorbed to a potential gap portion by exposure of a photoreceptor, except that the toner is dispersed in a petroleum-based solvent. This principle is not much different from an electrophotographic printer that attaches a normal powder toner. However, in the liquid development, only the toner is left on the photoreceptor in a state where the toner is dispersed in the solvent. Therefore, the unnecessary solvent must be removed.

In recent years, electrophotographic printers have been improved to bring them closer to photographic images for the purpose of high-speed, higher-definition image formation, and represent the fineness of the expression capability of one dot for image formation. The numerical resolution is 60
From 0 dpi to 1200 dpi, a higher resolution is required. Also, in the world of color printing, the above resolution is very important for more faithful color reproduction, and is a key technology of color printing together with a structure for increasing printing speed.

In order to form one dot with high resolution,
The writing method of the optical system, which is an exposure means for forming an electrostatic latent image on the photoreceptor, is also important, but the development process of attaching toner to the electrostatic latent image formed by exposure is also important. In the case of the dry type in which the toner is directly adhered to the latent image portion, a problem of toner dust that the toner adheres to portions other than the exposed portion occurs. The higher the resolution, the higher the effect of such toner dust. In the case of powder, the effect is 600 dpi to 1200 dpi.
Is said to be near the limit.

[0005] A high-resolution printer is known to be free from such a problem of toner dust, and a liquid developing method using a liquid toner in a state where the toner is dispersed in a petroleum-based solvent is known. It is receiving attention as one type of high-definition color printer (color printer).

[0006] The configuration of such an electrophotographic printer of the liquid development is such that a toner obtained by adding a resin charge imparting agent or a charge stabilizer to pigment fine particles and dispersing and diluting the same with a petroleum-based liquid solvent is used as a liquid toner ( Ink), and the ink flows on the surface of a roller (developing roller) that holds a predetermined gap (0.1 to 0.2 mm) between the photosensitive member and the photosensitive member, and
An ink layer is formed by applying a DC electric field as a predetermined developing bias to the roller, and the toner in the ink adheres to a potential gap portion on the photoconductor caused by exposure.

With such a configuration, the toner in the ink is electrostatically adsorbed on the photoreceptor. Immediately after passing through the developing device, the solvent as the ink is covered on the adsorbed toner image. It remains, and the photoconductor is wet with the solvent. If this solvent covers the photoreceptor, it becomes impossible to carry the next color image in color printing, so a squeeze mechanism for removing only the solvent is provided. Simply put, this squeeze mechanism presses a roller against the surface of the photoreceptor to pass only the toner electrostatically attracted to the surface of the photoreceptor, and removes the solvent by squeezing the photoreceptor with this roller. Is what you do.

FIG. 7 shows an example of a tandem-type color electrophotographic printer which continuously forms four-color images by a liquid developing method using a belt-shaped photosensitive member. Hereinafter, the configuration of the printer will be briefly described.

FIG. 7 shows a configuration of the rotating photosensitive belt 501 viewed from the lateral direction.
01 through a motor and a gear transmission system (not shown) for rotating the drive roller 502 and the transfer backup roller 5
03 and a steering roller 504 having a control mechanism so that the belt rotates at a fixed position. Further, between the steering roller 504 and the drive roller 502, a plurality of holding rollers 505 and auxiliary stays 506 are provided.
As a result, the conveyance path of the photoreceptor belt 501 is charged, exposed,
The photoconductor belt 501 is held so as to pass through each part of the development and a predetermined position, and rotates in the direction of the arrow shown in the figure.

On the other hand, each of the above-mentioned parts of charging, exposure and development has a charger 510 by corona discharge in the rotation direction of the photosensitive belt 501 in order, and then a laser diode, a polygon motor 511 and a lens 512 (not shown). Is provided, followed by a developing unit 514, and in order of yellow (Y), magenta (M), cyan (C), and black (K), each of these three The components of the part are arranged.

As described before the description, the developing device 514 includes a developing roller 516 (an ink in the drawing) which is capable of forming an ink layer 515 on which a toner is dispersed in a solvent as an ink layer on the surface. Although it is expressed as if it is immersed in 515, in actuality, the density is adjusted on the supply side and the ink reservoir after development so that the ink 515 circulates.) And a predetermined gap is maintained. Further, after the photosensitive belt 501 passes through the developing roller 516, a squeeze roller 5 that applies pressure to each other is provided.
A squeeze mechanism is constituted by the squeeze roller 17 and the squeeze backup roller 518.

After passing through the four-color charging / exposure / development parts thus constructed, the driving roller 502
A drying means (not shown) is added in the vicinity of, so that the toner image on the photoreceptor belt 501 includes only the toner component. Next, by passing between the transfer backup roller 503 and the transfer roller 520, the toner image on the photosensitive belt 501 is temporarily transferred onto the transfer roller 520, and the recording paper 522 held in the paper cassette 521 is image-formed. The toner image is transferred to the recording paper 522 by running the transfer roller 520 at the position and timing in synchronization. Further, in order to stably fix the toner image transferred and formed on the recording paper 522 on the recording paper 522 in a stable state, the toner image passes through a fixing device 523 which applies heat and pressure.

FIG. 8 is a sectional view showing only a conventional squeezing mechanism provided in the developing device 514. less than,
The squeeze mechanism will be described.

This squeezing mechanism is composed of a tubular roller 60 having a conductive rubber layer 603 on a surface supported by a rotating shaft 602.
4, a pressure is applied between the squeeze roller 517 and the back-up roller 518 so as to sandwich the photoreceptor belt 501. With this pressure, a toner image (not shown) covered with a solvent layer 606 formed on the photoreceptor belt 501 is formed. The solvent is squeezed out.

The squeezed roller 5
A solvent pool 607 is formed on the side of the roller 17 which enters the contact portion with the photoreceptor belt 501, flows along the outer peripheral surface of the squeeze roller 517, flows into the liquid pool 608, and drains 609.
Is discharged to the outside.

The conductive rubber layer 603 formed on the tubular roller 604 can contact the toner image (not shown) formed on the photoreceptor belt 501 only by applying pressure using two rollers. Squeeze roller 5
17 adhere to the surface side. Therefore, after the conductive rubber layer 603 has an appropriate resistance value,
2, a developing roller 5 at a stage prior to the squeezing mechanism.
If the same potential as the developing bias voltage applied to the roller 16 is applied, the toner image (not shown) formed on the photoreceptor belt 501 can be reduced from adhering to the contacting roller surface side.

FIG. 9 is a sectional view showing a conventional squeezing mechanism of a developing device of an electrophotographic printer using a photosensitive drum instead of a photosensitive belt. Photoconductor drum 60
Other than 1 is the same as the squeeze mechanism shown in FIG.

[0018]

Even in the squeezing mechanism of the liquid developing system described above, the toner image on the photoreceptor belt 501 does not remain on the 100% photoreceptor belt 501, and the photoreceptor belt 501 remains after development. The floating toner (not shown), which is not electrostatically attached to the toner and remains in the solvent, is in contact with the squeeze roller 51 by applying pressure.
7 and is transferred to the photoreceptor belt 501 again after the squeeze roller 517 has rotated one turn, which causes a so-called offset problem.

An object of the present invention is to provide a squeezing mechanism in which only toner for image formation is passed from an image forming portion covered with a solvent on the surface of a photoreceptor after development, and only the remaining solvent is squeezed out. Some of the toner of this image is transferred to the surface of the squeeze roller without remaining on the photoreceptor side, but the transferred toner remains on the squeeze roller even after one rotation of the squeeze roller. An object of the present invention is to provide a squeeze mechanism that does not return to the entrance side of the contact portion with the squeeze.

[0020]

A squeeze mechanism of a liquid developing system is a squeeze mechanism which is developed by using a liquid toner in which a toner is dispersed in a solvent (101 in FIG. 1), and presses the photosensitive body. A conductive squeeze roller that rotates with the rotation or movement of the photoconductor (103 in FIG. 1)
And receiving the solvent separated from the photoconductor and flowing along the outer peripheral portion of the squeeze roller on the side of entry to the contact portion (106 in FIG. 1) between the photoconductor and the squeeze roller and discharging the solvent to the outside. A liquid receiver (112 in FIG. 1);
A solvent is provided at an outlet side (105 in FIG. 1) of a liquid pool provided on an outer peripheral surface of the squeeze roller from a contact portion with the photoconductor and continuous with the liquid receiver, and a solvent is provided at an outlet side of the liquid pool. Supply means (108 in FIG. 1) for supplying
A plurality of outlet-side electrodes (P1 to P9 in FIG. 1) which are arranged side by side in the circumferential direction of the squeeze roller at the outlet-side portion of the liquid pool and are long in the axial direction of the squeeze roller; Voltage applying means (121 in FIG. 1) for applying a predetermined voltage by moving in order in the direction of rotation of the squeeze roller from the contact portion side
And characterized in that:

The squeezing mechanism of the liquid developing system according to the present invention comprises a photosensitive member (101 in FIG. 1) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 1) that rotates with the rotation or movement of the body, and a contact portion (10 in FIG. 1) between the photoconductor and the squeeze roller.
A liquid receiver (112 in FIG. 1) that receives a solvent separated from the photoreceptor and flowing along the outer peripheral portion of the squeeze roller on the entry side to (6) and discharges the solvent to the outside; An outlet side portion (105 in FIG. 1) of a liquid pool provided on an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver, and a solvent supply unit (105) for supplying a solvent to the outlet side portion of the liquid pool ( 1), and a rear wall of the insulator (1 in FIG. 1) which faces the outer peripheral surface of the squeeze roller with a gap at the outlet side portion of the liquid pool.
10), a plurality of outlet electrodes (P1 to P9 in FIG. 1) embedded in the rear wall so as to be arranged in the circumferential direction of the squeeze roller and long in the axial direction of the squeeze roller, and the plurality of outlet electrodes. Each of which includes a voltage applying means (121 in FIG. 1) for applying a predetermined voltage by moving in the order in which the squeeze roller rotates in the direction of rotation of the squeeze roller from the contact portion side.

The squeezing mechanism of the liquid developing system of the present invention comprises a photosensitive member (101 in FIG. 1) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 1) that rotates with the rotation or movement of the body, and a contact portion (10 in FIG. 1) between the photoconductor and the squeeze roller.
A liquid receiver (112 in FIG. 1) that receives a solvent separated from the photoreceptor and flowing along the outer peripheral portion of the squeeze roller on the entry side to (6) and discharges the solvent to the outside; An outlet side portion (105 in FIG. 1) of a liquid pool provided on an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver, and a solvent supply unit (105) for supplying a solvent to the outlet side portion of the liquid pool ( 1 and a rear wall of the insulator (4 in FIG. 4) opposed to the outer peripheral surface of the squeeze roller at a gap on the outlet side of the liquid pool.
03), a plurality of outlet-side electrodes (401 in FIG. 4) embedded in the rear wall so as to be arranged in the circumferential direction of the squeeze roller and elongated in the axial direction of the squeeze roller, and the surface of each of the outlet-side electrodes. An opening (404 in FIG. 4) provided in the rear wall to be exposed toward the squeeze roller;
Voltage applying means (12 in FIG. 1) for applying a predetermined voltage to each of the plurality of outlet electrodes from the contact portion side in the order in which the squeeze rollers rotate.
1).

The squeezing mechanism of the liquid developing system of the present invention comprises a photosensitive member (101 in FIG. 1) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 1) that rotates with the rotation or movement of the body, and an outer peripheral portion of the squeeze roller separated from the photoconductor at a side of entry to a contact portion between the photoconductor and the squeeze roller. A liquid receiver (112 in FIG. 1) for receiving the transmitted solvent and discharging the same to the outside, and an outer peripheral surface of the squeeze roller provided on an outlet side from a contact portion with the photoconductor and continuous with the liquid receiver. The outlet side of the liquid pool (10 in FIG. 1)
5), a solvent supply means (108 in FIG. 1) for supplying a solvent to the outlet side portion of the liquid pool, and a shaft of the squeeze roller which is arranged in the circumferential direction of the squeeze roller at the outlet side portion of the liquid pool. A plurality of outlet electrodes (401 in FIG. 1) that are long in the direction, and an insulating electrode that protrudes from the surface of the outlet electrode and that secures a gap between the surface of the outlet electrode and the outer peripheral surface of the squeeze roller. A projection and voltage application means (121 in FIG. 1) for applying a predetermined voltage to each of the plurality of outlet electrodes from the contact portion side in the order in which the squeeze rollers rotate in the order of rotation. The electrode projection may be a stay (402 in FIG. 1) provided on the surface of the electrode at an angle to the rotation direction of the squeeze roller. Electrode protrusion is obliquely with respect to the rotational direction of the squeeze roller to the surface of the electrode, yet can also be such that a plurality of stays that are arranged in net-like cross each other.

The squeezing mechanism of the liquid developing system of the present invention comprises a photosensitive member (101 in FIG. 5) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 5) that rotates with the rotation or movement of the body, and a contact portion (10 in FIG. 5) between the photoconductor and the squeeze roller.
And a liquid receiver (112 in FIG. 5) for receiving a solvent separated from the photoreceptor and flowing along the outer peripheral portion of the squeeze roller at the entrance side to the outer peripheral surface of the squeeze roller. An outlet side portion (105 in FIG. 5) of a liquid pool provided on the outlet side from the contact portion with the photoconductor and continuous with the liquid receiver, and a solvent supply unit (105) for supplying a solvent to the outlet side portion of the liquid pool ( 5), a plurality of conductive electrode rollers (454 in FIG. 5) arranged in parallel in the circumferential direction of the squeeze roller at the outlet side portion of the liquid pool and parallel to the squeeze roller, and the plurality of electrodes. Each of the rollers includes a voltage applying means (121 in FIG. 1) for applying a predetermined voltage by moving in an order arranged in the rotation direction of the squeeze roller from the one on the contact portion side.

The squeezing mechanism of the liquid developing system of the present invention comprises a photosensitive member (101 in FIG. 5) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 5) that rotates with the rotation or movement of the body; and an outer periphery of the squeeze roller separated from the photosensitive body on the side of entry into a contact portion () between the photosensitive body and the squeeze roller. A liquid receiver (112 in FIG. 5) for receiving the solvent flowing through the portion and discharging the solvent to the outside, and a liquid receiver provided on an outer peripheral surface of the squeeze roller at an outlet side from a contact portion with the photoconductor. An outlet part (105 in FIG. 5) of the continuous liquid pool, a solvent supply means (108 in FIG. 5) for supplying a solvent to the outlet part of the liquid pool, A plurality of conductive electrode rollers (454 in FIG. 5) arranged in parallel with the squeeze roller in the circumferential direction of the squeeze roller, and provided on the outer peripheral surface of the electrode roller so as to protrude from the outer peripheral surface of the electrode roller; A roller protrusion (455 in FIG. 5) for securing a gap with the outer peripheral surface of the roller; and a predetermined voltage applied to each of the plurality of electrode rollers by moving from the contact portion side in the order in which the squeeze roller rotates. And a voltage applying means (121 in FIG. 1) for adding the voltage.

The squeezing mechanism of the liquid developing system described above
Preferably, the voltage application unit causes a moving speed of the outlet electrode or the electrode roller to which a predetermined voltage is applied to correspond to a rotation speed of the squeeze roller.

The squeeze mechanism of the liquid developing system described above
The voltage applying means applies a periodic pulse of a first voltage having a fixed time width to each of the outlet-side electrodes or each of the outlet-side rollers, and a second voltage for a time other than the pulse, and The side electrode or the electrode roller to which the pulse is applied is sequentially switched from the side of the contact portion to the side adjacent to the squeeze roller in the rotation direction.

The squeezing mechanism of the liquid developing system of the present invention comprises a photosensitive member (101 in FIG. 5) which is developed using a liquid toner in which a toner is dispersed in a solvent, and the photosensitive member while pressing the photosensitive member. A conductive squeeze roller (103 in FIG. 5) that rotates with the rotation or movement of the body, and a contact portion (10 in FIG. 5) between the photoconductor and the squeeze roller.
And a liquid receiver (112 in FIG. 5) for receiving a solvent separated from the photoreceptor and flowing along the outer peripheral portion of the squeeze roller at the entrance side to the outer peripheral surface of the squeeze roller. An outlet side portion (105 in FIG. 5) of a liquid pool provided on the outlet side from the contact portion with the photoconductor and continuous with the liquid receiver, and a solvent supply unit (105) for supplying a solvent to the outlet side portion of the liquid pool ( 5), a conductive electrode roller (454 in FIG. 5) provided in parallel with the squeeze roller at the outlet side of the liquid pool, and the electrode protruding from the outer peripheral surface of the electrode roller. An insulating roller projection for securing a gap between the outer peripheral surface of the roller and the outer peripheral surface of the squeeze roller, and voltage applying means (121 in FIG. 1) for applying a predetermined voltage to the outlet roller. The roller protrusion may be a spiral protrusion (455 in FIG. 6), and the roller protrusion may be a plurality of intersecting spiral protrusions provided in a net shape. .

The squeeze mechanism of the liquid developing system described above
Preferably, a liquid receiving electrode (Pz in FIG. 1) facing the squeeze roller is provided at the position of the liquid receiver, and an AC voltage offset by a voltage applied to the squeeze roller is applied to the liquid receiving electrode. What should I do?

In the squeezing mechanism of the liquid developing system described above, the solvent supply means desirably includes a part of the solvent separated from the photoconductor on the side of the photoconductor entering the contact portion. Feed it to the outlet side of the pool.

The squeezing mechanism of the liquid developing system of the present invention aims to prevent a part of image formation and toner floating in a solvent from adhering to the squeezing mechanism itself. A plurality of electrodes are arranged on the surface, and by applying a voltage to the electrodes, different potential changes can be given at the rotational position of the squeeze roller.

In one embodiment of the present invention, a plurality of electrodes are arranged on the side of the surface of the squeeze roller which has passed through the contact portion with the photoreceptor, and the contact portion with the photoreceptor is arranged at the portion where the plurality of electrodes are arranged. The squeezed solvent is fed at the entrance side of the squeeze roller to form a liquid pool, and electrophoresis occurs in the toner between the plurality of electrodes and the surface potential of the squeeze roller. However, the voltage application to the plurality of electrodes is switched so as not to adhere to the electrodes, and because of the voltage switching, the peeled toner follows the flow circulating through the liquid pool and enters the drain port. Is discharged.

In this way, when the surface of the squeeze roller returns to the contact portion again in contact with the photosensitive member by rotation, the squeeze roller is in a clean state where the toner has been removed.
Image stains (offset images and the like) due to toner attached to the squeeze roller do not occur.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings showing the configuration.

FIG. 1 is a side sectional view of a squeeze roller showing a squeeze mechanism of a liquid developing system according to a first embodiment of the present invention, as viewed from a lateral direction.

In FIG. 1, the photosensitive belt 101 is sandwiched between the squeeze roller 103 and the backup roller 125 to apply pressure.

The squeeze roller 103 is formed of the conductive rubber layer 1.
Reference numeral 02 denotes a metal roller formed on the outer peripheral portion, which rotates around the rotation shaft 104 and rotates by the movement of the photosensitive belt 101 which is in pressure contact. Photoreceptor belt 1
A solvent pool 107 is formed by the solvent squeezed from the photoreceptor belt 101 on the side of the squeeze roller 103 that contacts the squeeze roller 103. A part of the solvent reservoir 107 is circulated to the side that has passed through the photoconductor contact 106 by a solvent flow path 108 and a circulating means such as a pump (not shown), and the liquid reservoir 105 is formed.

Contact portion 1 on the outer periphery of squeeze roller 103
A front wall 109 is provided so as to cover a portion on the approach side to the rear portion 106, and a rear wall 110 is provided so as to cover a portion on the exit side from the contact portion 106.
0.5 mm between the outer peripheral surface of the squeeze roller 103
A gap of about 1 mm is provided. A liquid receiver 112 is attached to a lower portion of the squeeze roller 103 between the front wall 109 and the rear wall 110 so as to form a larger space between the front wall 109 and the outer periphery of the squeeze roller 103 than the gap.

An outer wall 126 is further provided outside the front wall 109, and a solvent flow path 108 connecting the inside of the outer wall 126 and the end of the rear wall 110 on the contact portion 106 side is provided. Solvent pool 10
7 flows into the liquid receiver 112 through the space between the front wall 109 and the outer periphery of the squeeze roller 103, and a part of the solvent is sent through a solvent flow path 108 by circulating means such as a pump (not shown). 110 and squeeze roller 1
The liquid flows into the liquid receiver 112 through the gap between the outer periphery of the liquid supply device 03 and the outer periphery of the liquid supply device 03. A liquid reservoir 111 is formed in the liquid receiver 112, and a liquid reservoir 105 is formed between the rear wall 110 and the outer periphery of the squeeze roller 103.
Is formed, and the front wall 109 and the squeeze roller 10 are formed.
3 and a liquid pool is formed.

The liquid receiver 112 is connected to a drain port 113 for returning the solvent to an ink holding section (not shown). The solvent is monitored by a liquid level sensor or the like (not shown),
The operation of a pump provided in the solvent flow path 108 (not shown) and a control valve provided in front of the drain light causes the liquid pool 1 to operate.
05 and 111 are always filled with the solvent.

FIG. 2 is a partially enlarged view of FIG. 1 showing the rear wall 110 in particular. As an electrical configuration, as shown in FIG. 2, on the rear wall 110, the outlet-side electrodes P <b> 1 to P <b> 1 are arranged so that the angle around the rotation axis 104 is in increments of 8 degrees and are long in the direction of the rotation axis 104. Nine P9 are embedded,
From the side close to the contact portion 106, the outlet electrodes P1, P2, P
3, P4, P5, P6, P7, P8, P9. Also, a liquid receiving electrode PZ that is long in the direction of the rotating shaft 104 is embedded at the bottom of the liquid receiver 112.

The exit side electrodes P1, P4 and P
7 are commonly electrically connected to the extraction line Vc1, and the outlet electrodes P2, P5 and P8 are commonly connected to the electrode extraction line Vc1.
c2, and the outlet-side electrodes P3, P6 and P9 are commonly connected to an electrode lead-out line Vc3. The electrode extraction lines Vc1, Vc2, and Vc3 are connected to the transfer voltage generation circuit 121 as shown in FIG. 1, and the voltage Vc generated by the negative DC power supply 122 connected to the transfer voltage generation circuit 121 is switched and added. ing.

The liquid receiving electrode PZ is connected to an AC power supply 123. Further, a rotating shaft 104 electrically integrated with the squeeze roller 103 has a DC power source 1 for generating a voltage Vb substantially equal to the surface potential of the photosensitive belt 101 after development.
24 connected to the liquid receiving electrode PZ.
Reference numeral 23 denotes an offset applied by the voltage Vb generated by the DC power supply 124.

The transfer voltage generating circuit 121 switches from the electrode extraction line Vc1 to Vc2 to Vc3 to sequentially apply the voltage Vc of the connected negative DC power supply 122, and when the voltage reaches the voltage extraction line Vc3, the voltage is again increased. Extraction line Vc
It returns to 1 and this is repeated.

FIG. 3 shows the voltages of the extraction electrodes Vc1, Vc2 and Vc3 to which the transfer voltage generation circuit 121 switches and applies the voltage Vc, the voltage Vb applied to the rotating shaft 104, and the voltage Vz of the AC power supply 123 applied to the electrode PZ. The change is shown with time on the horizontal axis, and the vertical axis shows each voltage on the basis of 0V. As shown in this figure, the voltage Vc is switched from the extraction electrode Vc1 to Vc2 and Vc3, and the AC voltage Vz is a pulsating voltage shifted by the voltage Vb.

Although the voltage Vz shown in FIG. 3 is represented by a sine wave, it may be a rectangular wave. The time on the horizontal axis and the timing of the voltage for switching from the extraction electrode Vc1 to Vc3 depend on the rotational speed of the surface of the squeeze roller 103, which is the process speed. In practice, the optimum speed is experimentally operated. Can be determined by evaluating the result.

Although a conductive rubber (conductive rubber layer 102) is described as a material of the surface of the squeeze roller 103, the material is not limited to rubber as long as it is a material having high softness in place of rubber. Further, a conductive material whose surface is covered with a thin insulator may be used. The necessary condition is that a gap cannot be formed at the contact point with the photoreceptor. Further, the conductive rubber may be an anisotropic conductive rubber having high electric resistance in the circumferential direction and low electric resistance in the thickness direction.

The operation of the squeeze mechanism of the liquid developing system according to the present embodiment is as follows.

When the surfaces of the photoreceptor belt 101 and the squeeze roller 103 pass through the contact portion 106, as shown in the enlarged view of FIG. Of the image forming toner 201 or the toner 202 that has not been electrostatically attached to the photosensitive belt 101.
Is attached.

The slip-through toner 202 adhered to the surface
The rear wall 110 is rotated with the rotation of the squeeze roller 103.
And enters the pool 105 formed between them.
Further, when entering the liquid reservoir 105, the voltage V applied by switching to the extraction electrodes Vc1, Vc2, and Vc3 applied to the outlet electrodes P1 to P9 embedded in the rear wall 110 is applied.
c, attached to the surface of the squeeze roller 103;
The slip-through toner 202 causes an electrophoretic phenomenon due to a potential difference between the surface potential of the squeeze roller 103 and the voltage Vc applied to the outlet electrodes P1 to P9, is peeled off from the surface of the squeeze roller 103, and floats in the solvent. I do.

As shown in FIG. 3, the extraction electrodes Vc1, Vc
When the voltage Vc is switched and applied to c2 and Vc3, the outlet electrodes P1, P4, and P4 formed on the rear wall 110 are switched.
7, after the voltage Vc is applied, the outlet electrodes P2, P5,
The voltage Vc is applied to P8, and then the output side electrode P
3, the voltage Vc is applied to P6 and P9,
The outlet electrodes P1 to P9 to which the voltage Vc is applied are sequentially switched with time in the rotation direction of the squeeze roller 103. The speed at which the voltage to which the voltage Vc is applied to the outlet electrodes P1 to P9 is switched and the speed at which the voltage moves is switched from Vc1 to Vc2 to Vc3.
It is preferable to match the peripheral speed of the surface of the squeeze roller 103, which is the process speed. In this way, the extraction electrode Vc1 → Vc2 → to which the voltage Vc is applied to adjust the speed.
The transfer voltage generation circuit 121 is controlled by a microcomputer (not shown) at the timing of switching to Vc3.

Accordingly, the exit-side electrodes P1 to P9 that cause electrophoresis of the squeeze toner 202 move in accordance with the rotation of the squeeze roller 103, and the squeeze toner 202 peeled off from the surface of the squeeze roller 103 is The liquid flows from the liquid pool 105 in the direction of the drain port 113 shown in FIG. At this time, drain port 1
13, a squeeze roller 1
AC voltage V offset by the potential of surface 03
Since z has been added, the slip-through toner 202 that has flowed into the liquid pool 111 is electrophoretically neutralized, and does not precipitate and condense in the liquid pool 111, but flows to the drain port 113. Flowing out.

As a result, the surface of the squeeze roller 103 which returns to the side where it enters the contact portion 106 with the photoreceptor belt 101 can be kept clean, so that the squeeze mechanism itself does not stain the image. As described above, in the squeeze mechanism of the liquid developing system shown in FIGS. 1 and 2, the surface potential on the squeeze roller 103 is set to have a necessary potential at the contact portion 106 pressed against the photosensitive belt 101. By switching the voltage applied to the plurality of electrodes P <b> 1 to P <b> 9 with respect to the toner 202 having passed through the contact portion 106, the toner 202 is removed while the toner is peeled off by the electrophoresis. Since it can be put on the flow to the drain port 113, a part of the image on the squeeze roller 103 and the adhesion of the toner floating in the solvent, which is a main cause of the image stain in the conventional squeeze mechanism, are not removed. As a result, image contamination can be completely prevented.

In the squeeze structure of the liquid developing system shown in FIGS. 1 and 2, a contact portion 106 with the photosensitive belt 101 is provided.
Exit-side electrodes P1 to P9 are provided in the rear wall 110 on the side where
Are shown in an embedded state, but the exit-side electrodes P1 to P9
Is for causing electrophoresis, so that the outlet side electrode is in direct contact with the liquid pool 105 while the rear wall 11
Desirably, it is on the inner surface of 0. However, arranging the exit-side electrode in a bare manner causes an increase in cost due to the accuracy of the structure supporting the exit-side electrode and the management of the gap with the squeeze roller.

FIG. 4 shows a liquid developing type squeezing mechanism according to a second embodiment of the present invention in which the outlet electrode can be brought into direct contact with the liquid pool without making the precision and gap management difficult. FIG.
FIG. 9 is a perspective view of a part of a rear wall 403 of the vicinity thereof. Except for the exit side electrode 401 and the peripheral portion of the rear wall 403 around the electrode 401, the squeeze mechanism of the second embodiment also
It is the same as the squeeze mechanism shown in FIGS. 1 and 2,
A plurality of outlet-side electrodes 401 are provided on the rear wall 403 in parallel.

The exit side electrode 401 is also embedded in the rear wall 403.
Most of the front surface is exposed to the liquid pool. A gap holding stay 402 is formed obliquely on the front surface of the electrode 401, and this gap holding stay 402 is incorporated as a part of the rear wall 403. The gap holding stay 402 comes into contact with the conductive rubber material on the outer periphery of the squeeze roller, and the outlet electrode A gap is secured between the squeeze roller 401 and the
01 and the squeeze roller are not in direct contact with each other.

The outlet electrode may have a structure in which the outlet electrode is not embedded in the rear wall provided with the opening but is attached to the inner surface of the rear wall. Further, by increasing the manufacturing and assembling accuracy, the gap holding stay may not be provided.

FIG. 5 is a sectional view of a squeeze mechanism of a liquid developing system according to a third embodiment of the present invention. In this embodiment, an electrode roller 454 is used instead of the outlet electrodes P1 to P9.
The configuration is the same as that of the squeeze mechanism shown in FIGS. 1 and 2 except that the shape of the rear wall 451 is slightly changed accordingly.

In FIG. 5, an electrode roller 4 made of a plurality of metals is provided along the surface of the squeeze roller 103 along the surface of the squeeze roller 103 at the outlet side of the liquid pool 105.
54 are attached. FIG. 6 shows an electrode roller 454.
It is a perspective view of. A spiral ridge 455 made of an insulating material is formed on the outer peripheral surface of the electrode roller 454, and the ridge 455 is brought into contact with the surface of the squeeze roller 103. There is a certain gap between them. The electrode roller 454 is attached to a rotating shaft 456, and the rotating shaft 456 is supported by a bearing (not shown) provided at a portion following the rear wall 451.

The electrode roller 454 is also connected to a circuit similar to the transfer voltage generation circuit 121 via the rotating shaft 456, similarly to the outlet electrodes P1 and P2 shown in FIG. When a voltage is applied, the slip-through toner 202 is electrophoresed and sent to the liquid pool 111.

In the squeeze structure of the liquid developing system shown in FIG. 4, FIG. 5 and FIG. 6, the gap holding stay 402 or the ridge 455 is used to hold the gap between the electrode 401 or the electrode roller 454 and the squeeze roller 103. Squeeze roller 10
The electrode 401 or the roller 454 can be pressed against the conductive rubber layer 102 on the outer periphery of the roller 3, and the gap can be controlled by the thickness of the stay 402 or the ridge 455. Accuracy and the like do not affect the squeeze performance, and the squeeze mechanism has a high cleaning effect.

When the stay 402 or the ridge 455 is provided in the rotational movement direction of the outer periphery of the squeeze roller 103, the stay 402 and the ridge 455
There is a risk that the image will always be in contact with only a specific position on the three surfaces, which may affect the image. However, by making the stay 402 slanted and making the ridges spiral, the effect on the image can be avoided. However, the stay provided on the outlet electrode is not limited to the one shown in FIG.
A mesh-like structure in which a plurality of stays oblique in the direction are arranged so as to cross each other may be used. The same applies to the ridges provided on the electrode roller.

In the embodiment shown in FIGS. 2 and 3, nine outlet electrodes P1 to P9 are formed and connected every third electrode to apply three voltage changes. The number of the voltage changes, that is, the number of divisions of the voltage change, is not limited to nine, and the voltage may be switched in a direction in which the toner can flow through the liquid accumulation portion as viewed from the rotational movement of the surface of the squeeze roller. For example, there is no problem even if the electrode here is divided into any number.

The AC voltage is applied to the liquid receiving electrode Pz formed below the liquid pool 111 at the portion passing through the rear wall 110 where the plurality of outlet electrodes P1 to P9 are formed.
Since the flow of the solvent up to the drain port 113 does not cause the precipitation of the toner, the liquid receiving electrode Pz to which the AC voltage is applied may be omitted.

Furthermore, in the above-described embodiment, only the photoreceptor belt is shown in the drawings, but the present invention is not limited to the photoreceptor belt. The squeeze mechanism is effective, and the only difference is the shape of collecting the solvent pool formed on the entrance side of the contact portion between the photoreceptor and the squeeze roller in the solvent flow path. The structure shown in FIG. 1 to FIG.

In the case of the structure in which the electrode roller 454 is provided as shown in the third embodiment, the spiral ridge 455 formed on the electrode roller can be seen from the contact with the squeeze roller by the rotation of the roller. For example, since this corresponds to the movement of the electrode, the effect of sending the electrophoresed toner to the drain port side can be obtained without switching the voltage to the rollers arranged in plural as shown in FIG. These change with the voltage applied to the electrode roller and the pitch of the ridges, and also relate to the flow rate of the solvent in the liquid pool supplied through the solvent flow path. Such optimum locations of the voltage and the flow velocity can be determined by experiments.

Further, in the first embodiment, as shown in FIG.
Although the liquid is supplied to the liquid reservoir 105 through the nozzle 8, the solvent may be supplied to the liquid reservoir 105 not from the solvent reservoir 107 but from a separately provided tank or the like containing the solvent.

[0068]

As described above, in the squeeze mechanism of the liquid developing system according to the present invention, a liquid pool is formed at the exit side of the squeeze roller from the contact portion with the photosensitive member, and the squeeze roller is formed at the exit side. By arranging a plurality of electrodes facing each other and sequentially moving one of the electrodes to which a predetermined voltage is applied in the rotation direction of the squeeze roller, the electrode passes through the contact portion from the photoconductor and passes through the squeeze roller. While peeling off the toner from the squeeze roller by electrophoresis, the toner can be discharged while being placed on the flow of the solvent in the liquid pool to the drain port. Therefore, in the conventional liquid developing squeeze mechanism, a part of the image, which is the main cause of the image stain, and the image stain due to the toner floating in the solvent and adhering to the squeeze roller re-adhering to the photosensitive member are completely eliminated. There is an effect that can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a squeeze mechanism of a liquid developing system according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a rear wall 110 and its periphery in FIG. 1;

FIG. 3 is a diagram showing a change in voltage applied to outlet electrodes P1 to P9 and a liquid receiving electrode Pz shown in FIG. 2;

FIG. 4 is a perspective view showing an outlet-side electrode used in a liquid developing type squeezing mechanism according to a second embodiment of the present invention.

FIG. 5 is a partial sectional view of a squeeze mechanism of a liquid developing system according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing an electrode roller 454 in FIG.

FIG. 7 is a configuration diagram illustrating a color electrophotographic printer using a liquid developing system.

8 is a cross-sectional view showing a conventional liquid developing squeeze mechanism including a squeeze roller 517 and a backup roller 518 in FIG.

FIG. 9 is a cross-sectional view of a conventional liquid developing squeeze mechanism using a photosensitive drum 601.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Photoreceptor belt 102 Conductive rubber layer 103 Squeeze roller 104 Rotating shaft 105 Liquid pool 106 Contact part 107 Solvent pool 108 Solvent flow path 109 Front wall 110 Rear wall 111 Liquid pool 112 Liquid receiver 113 Drain port 121 Transfer voltage generation circuit 122 DC power supply 123 AC power supply 124 DC power supply 125 Backup roller 126 Outer wall 201 Image forming toner 202 Passing toner 401 Exit side electrode 402 Gap holding stay 403 Rear wall 404 Opening 451 Rear wall 454 Electrode roller 455 Protrusion 456 Rotation axis 501 Photoconductor belt 502 Drive roller 503 Transfer backup roller 504 Steering roller 505 Holding roller 506 Auxiliary stay 510 Charger 511 Polygon motor 512 Lens 513 Laser scanner 5 4 puddle developing device 515 ink 516 developing roller 517 squeeze roller 518 the backup roller 520 transfer roller 521 paper cassette 522 recording paper 523 fuser 601 photosensitive drum 602 rotating shaft 603 conductive rubber layer 606 solvent layer 607 solvent reservoir 608 solution

Claims (16)

[Claims] 1. A photoreceptor that is developed using a liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates with the rotation or movement of the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A plurality of outlet electrodes long in the axial direction of the squeeze roller and juxtaposed in a circumferential direction of the squeeze roller at an outlet side portion of the pool, and a plurality of outlet electrodes in front of each of the plurality of outlet electrodes. A squeezing mechanism of a liquid developing system, comprising: voltage applying means for applying a predetermined voltage by moving in order from the contact portion side in the direction of rotation of the squeezing roller. 2. A photoreceptor to be developed using liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates while rotating or moving the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A rear wall of the insulator facing the outer peripheral surface of the squeeze roller at an outlet side portion of the pool with a gap, and is embedded in the rear wall so as to be aligned in a circumferential direction of the squeeze roller. A plurality of outlet-side electrodes that are long in the axial direction of the squeeze roller, and a predetermined voltage is applied to each of the plurality of outlet-side electrodes by moving from the contact portion side in the order in which the squeeze roller rotates. A squeezing mechanism of a liquid developing system, comprising: a voltage applying unit. 3. A photoreceptor to be developed using liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates with the rotation or movement of the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A rear wall of the insulator facing the outer peripheral surface of the squeeze roller at an outlet side portion of the pool with a gap, and is embedded in the rear wall so as to be aligned in a circumferential direction of the squeeze roller. A plurality of outlet electrodes long in the axial direction of the squeeze roller, an opening provided in the rear wall that exposes a surface of each of the outlet electrodes toward the squeeze roller, and a plurality of the outlet electrodes. A voltage applying means for applying a predetermined voltage by moving in order from the contact portion side in the rotation direction of the squeeze roller, and a voltage application means for applying a predetermined voltage. 4. A photoreceptor that is developed using liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates with the rotation or movement of the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A plurality of outlet electrodes long in the axial direction of the squeeze roller and juxtaposed in the circumferential direction of the squeeze roller at the outlet side portion of the pool, and protrudingly provided on the surface of the outlet electrode. An insulating electrode projection that secures a gap between the surface of the outlet-side electrode and the outer peripheral surface of the squeeze roller; and a rotation direction of the squeeze roller from the contact portion side to each of the plurality of outlet-side electrodes. A liquid application type squeezing mechanism, comprising: voltage applying means for applying a predetermined voltage by moving in a line order. 5. The liquid developing squeezing mechanism according to claim 4, wherein the electrode projection is a stay provided on the surface of the electrode at an angle to the rotation direction of the squeezing roller. 6. The electrode projection comprises a plurality of stays disposed on the surface of the electrode obliquely with respect to the rotation direction of the squeeze roller and in a net-like manner so as to intersect with each other. 4. A squeeze mechanism of a liquid developing system according to item 1. 7. A photoreceptor that is developed using liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates while rotating or moving the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A plurality of conductive electrode rollers parallel to the squeeze roller and arranged in parallel in the circumferential direction of the squeeze roller at an outlet side portion of the pool, and each of the plurality of electrode rollers A voltage applying means for applying a predetermined voltage by moving in an order arranged in the rotation direction of the squeeze roller from the contact portion side. 8. A photoreceptor that is developed using liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates while rotating or moving the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A plurality of conductive electrode-side rollers parallel to the squeeze roller and juxtaposed in the circumferential direction of the squeeze roller at the outlet side of the pool, and protruding from the outer peripheral surface of the electrode roller. A roller projection that secures a gap between the outer peripheral surface of the electrode roller and the outer peripheral surface of the squeeze roller, and the order in which the plurality of electrode rollers are arranged in the rotational direction of the squeeze roller from the contact portion side on each of the plurality of electrode rollers. And a voltage applying means for applying a predetermined voltage by moving. 9. The squeezing roller according to claim 1, wherein said voltage applying means causes a moving speed of said outlet electrode or said electrode roller to which a predetermined voltage is applied to correspond to a rotating speed of said squeezing roller. The squeeze mechanism of the liquid development system according to any one of the above. 10. The voltage applying means applies a periodic pulse of a first voltage having a fixed time width to each of the outlet-side electrodes or each of the outlet-side rollers and a second voltage for a time other than the pulse. It is characterized in that the application of the pulse on the exit side electrode or the electrode roller is sequentially switched from the one on the contact portion side to the one adjacent in the rotation direction of the squeeze roller. The squeezing mechanism of the liquid development system according to claim 1. 11. A photoreceptor that is developed using a liquid toner in which a toner is dispersed in a solvent, a conductive squeeze roller that rotates while rotating or moving the photoreceptor while pressing the photoreceptor, A liquid receiver for receiving a solvent separated from the photoconductor and flowing along an outer peripheral portion of the squeeze roller on an entrance side to a contact portion between the photoconductor and the squeeze roller and discharging the solvent to the outside; An outlet side portion of a liquid pool provided on an outer peripheral surface at an outlet side from a contact portion with the photoreceptor and continuous with the liquid receiver; a solvent supply unit configured to supply a solvent to an outlet side portion of the liquid pool; A conductive electrode roller provided in parallel with the squeeze roller at the outlet side of the pool; and an outer peripheral surface of the electrode roller protruding from an outer peripheral surface of the electrode roller. A squeezing mechanism of a liquid developing system, comprising: an insulating roller protrusion for securing a gap with an outer peripheral surface of a squeeze roller; and voltage applying means for applying a predetermined voltage to the outlet roller. 12. The squeezing mechanism according to claim 8, wherein the roller projection is a spiral ridge. 13. The liquid developing squeezing mechanism according to claim 12, wherein the roller protrusion is a plurality of spiral ridges provided in a net shape and intersecting with each other. 14. A squeezing mechanism according to claim 1, wherein a liquid receiving electrode is provided at a position of said liquid receiver so as to face said squeeze roller. 15. The squeezing mechanism according to claim 14, wherein an AC voltage offset by a voltage applied to the squeezing roller is applied to the liquid receiving electrode. 16. The method according to claim 16, wherein the solvent supply unit feeds a part of the solvent separated from the photoconductor on an entrance side of the photoconductor to the contact portion to an outlet side of the liquid reservoir. Item 16. A liquid developing squeeze mechanism according to any one of Items 1 to 15.