JP2008111975A - Liquid developer removal device and liquid development device with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid developer removal device capable of appropriately removing liquid developer remaining on the surface of a liquid developer carrier, and to provide a liquid development device. <P>SOLUTION: Liquid developer accumulated near the leading edge 24 of a cleaning blade 19 is scraped by the long axial end 26 of a rotating sweep roller 22. The shortest distance between the rotating axial line of the sweep roller 22 and a guide 23 is set shorter than a half of the long diameter of the sweep roller 22. Thereby, the long axial end 26 of the sweep roller 22 comes into contact with the guide 23 (refer to (a)). Since the guide 23 is film-like and flexible, the guide 23 is deformed by its contact with the sweep roller 22. Thereafter, the liquid developer is moved to a recovering position 21 by the sweep roller 22 (refer to (b)). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid developer removing device for removing a liquid developer remaining on a surface of a drum-like liquid developer carrying member, and a liquid developing device including the same.

In electrophotographic image forming apparatuses, the development of an electrostatic latent image on a photosensitive drum using powder toner is the mainstream, but a liquid developer in which toner particles are dispersed in a carrier liquid is used. There has been proposed a liquid developing apparatus that develops an electrostatic latent image by using it.
In this type of liquid developing apparatus, for example, development is performed by bringing a developing roller carrying a liquid developer into contact with the surface of the photosensitive drum. After development, the liquid developer remains on the surface of the developing roller, but from the viewpoint of image stability, the liquid developer remaining on the surface of the developing roller needs to be removed from the surface of the developing roller.

  The amount of liquid developer consumed in development is very small, and most of the liquid developer is not consumed and remains on the surface of the developing roller. Therefore, the liquid developer removed from the surface of the developing roller is not discarded but collected and recycled. Specifically, the removed liquid developer is collected and then mixed with a new liquid developer or carrier liquid to adjust the components. Then, the liquid developer whose component has been adjusted is supplied again to the developing roller, carried on the developing roller, and used for developing the electrostatic latent image.

As a method of removing the liquid developer from the surface of the developing roller, a method of stripping off the liquid developer adhering to the surface of the roller with a cleaning blade can be considered (for example, Patent Document 1).
The cleaning blade is disposed in an inclined posture so that the end surface is slightly directed toward the developing roller from the position extending in the tangential direction of the developing roller. For example, the cleaning blade is disposed so as to be inclined obliquely with respect to the horizontal plane so as to be lowered downward from the front end portion toward the rear.

The liquid developer peeled off by the cleaning blade moves rearward due to its own weight on the upper surface of the cleaning blade arranged in an oblique direction, is removed from the rear end of the cleaning blade, and is collected by the collecting device. It is being transported to.
JP 2001-296780 A

  However, the liquid developer remaining on the surface of the developing roller after development has a higher toner particle content ratio, higher concentration and higher viscosity than the liquid developer at the time of supply due to the influence of heat during development. Poor fluidity. Therefore, it is conceivable that the liquid developer peeled off from the developing roller by the cleaning blade does not flow well on the upper surface of the cleaning blade but accumulates on the upper surface of the cleaning blade. In this case, the liquid developer remaining on the developing roller cannot be stably recovered.

SUMMARY An advantage of some aspects of the invention is that it provides a liquid developer removing device that can appropriately remove a liquid developer remaining on the surface of a liquid developer carrying member.
Another object of the present invention is to provide a liquid developing apparatus capable of recovering the liquid developer efficiently and reliably.

  In order to achieve the above object, according to the first aspect of the present invention, the liquid developer remaining on the surface of the drum-shaped liquid developer carrying member (6) is removed and moved to a predetermined removal position (21). A liquid developer removing device (18) for causing a cleaning blade (which contacts the surface of the liquid developer carrying member to peel off the liquid developer remaining on the surface (6a) of the liquid developer carrying member. 19) and having an elliptical cross section, and rotating about the rotation axis (27) extending in parallel with the rotation axis of the liquid developer carrier, in the direction opposite to the rotation direction of the liquid developer carrier, The liquid developer peeled off by the cleaning blade is scraped out and moved toward the removal position, and the rotating body (22) is in the form of a film and has flexibility, the removal position and the tip of the cleaning blade Department ( 4), and a guide (23) for guiding the liquid developer moved by the rotating body to the predetermined removal position. It is.

The numbers in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.
According to this configuration, the rotating body in the rotating state directly moves the liquid developer toward the scraping removal position. The liquid developer moves on the guide and is guided to the removal position. When the rotating body comes into contact with the guide, the liquid developer is pushed by the rotating body that moves while closely contacting the guide. Therefore, the liquid developer is reliably and smoothly moved to the removal position. In this case, the liquid developer removed by the cleaning blade can be appropriately moved to the removal position.

  In addition, the elliptical rotator must be arranged so that it does not come into contact with the surface of the developing roller or the cleaning blade in its rotating state. On the other hand, the rotator is used for the liquid development peeled off by the cleaning blade. It is also necessary to uplift the agent. In the above configuration, the film-like guide is stretched between the removal position and the tip of the cleaning blade. The liquid developer peeled off by the cleaning blade does not move on the cleaning blade but moves on the guide and is guided to the removal position. And since a guide is a film form, even if a rotary body contacts a guide, there is no problem. For this reason, the positioning accuracy of the rotating body is not required to be high, and it takes less time to install the rotating body.

Examples of the drum-shaped liquid developer carrier include a photosensitive drum and a developing roller.
Furthermore, as in claim 2, the guide is arranged such that the shortest distance (A) from the rotation axis of the rotating body is shorter than the semi-major axis (B) of the rotating body, and the rotating body It is preferable that the liquid developer moved by is guided while being deformed.

The invention according to claim 3 is characterized in that one side (28) of the guide is fixed at the removal position and the other side (29) is lightly pressed against the cleaning blade. The liquid developer removing apparatus described.
According to this configuration, since only the other side of the guide that is lightly pressed against the tip of the cleaning blade is a free end, the other side swings relatively well. For this reason, the front end portion of the cleaning blade vibrates, and thereby the liquid developer can be prevented from being deposited on the front end portion of the cleaning blade.

According to a fourth aspect of the present invention, the rotating body is disposed so as to be closest to the surface of the liquid developer carrying body upstream of the tip of the cleaning blade. 4. The liquid developer removing device according to any one of items 3 to 3.
According to this configuration, the rotating body in the rotating state is closest to the liquid developer carrier on the upstream side of the cleaning blade. For this reason, the liquid developer to be deposited on the tip of the cleaning blade is scraped off by the rotating body. Thereby, it is possible to suppress the liquid developer from being deposited on the cleaning blade.

  According to the fifth aspect of the present invention, the drum-shaped developing roller (6) that carries the liquid developer and supplies the liquid developer to the photosensitive member, and the liquid developer remaining on the surface of the developing roller are removed. A liquid developer removing device (18) for recovering the liquid developer, and a recovery device (20) for recovering the liquid developer removed by the liquid developer removing device to a recovery path for recycling. A liquid developing device (1) characterized in that the liquid developer removing device according to any one of claims 1 to 4 is used as the device.

  According to this configuration, since the liquid developer removing device according to any one of claims 1 to 4 is provided, the liquid developer can be efficiently and reliably recovered.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic diagram showing a main part configuration of an image forming apparatus 100 to which a liquid developing apparatus 1 according to an embodiment of the present invention is applied.
The image forming apparatus 100 creates a cylindrical photosensitive drum 2, a charger 3 for charging the surface 2 a of the photosensitive drum 2, and a surface 2 a of the photosensitive drum 2 charged by the charger 3. An exposure device 4 for exposing corresponding to an image, and a liquid developer in which toner particles are dispersed in a carrier liquid are supplied to the surface 2a of the photosensitive drum 2, and an electrostatic latent image formed by exposure is supplied. The liquid developing device 1 for developing, the cleaning device 7 for removing the liquid developer remaining on the surface 2a of the photosensitive drum 2 after the toner image is transferred to the intermediate transfer belt 10, and the toner image are transferred. And a static eliminator 8 for neutralizing the surface of the subsequent photosensitive drum 2. The charger 3, the exposure device 4, the liquid developing device 1, the cleaning device 7, and the static eliminator 8 are sequentially arranged along the rotation direction of the photosensitive drum 2 (direction indicated by the arrow 9).

  The image forming apparatus 100 further includes an endless intermediate transfer belt 10 on which the developed toner image is temporarily transferred to the surface 2a of the photosensitive drum 2, and a driving roller 11 for driving the intermediate transfer belt 10. A tension roller 12 for applying tension to the intermediate transfer belt 10; and a secondary transfer roller 13 for transferring the toner image temporarily transferred to the intermediate transfer belt 10 to the paper P. .

The sheet P is conveyed along a line indicated by an upward arrow in FIG. 1, and a toner image is transferred to the surface of the sheet P when passing between the intermediate transfer belt 10 and the secondary transfer roller 13. The paper P to which the toner image has been transferred is heated and pressurized by a fixing device (not shown), whereby the toner image is fixed on the paper P.
FIG. 2 is a schematic diagram illustrating the configuration of the liquid developing device 1.

  The liquid developing device 1 is in contact with the surface 2 a of the photosensitive drum 2, and supplies the liquid developer to the surface 2 a of the photosensitive drum 2. In contact with both the supply pot 14 in which the liquid developer to be stored, the pumping roller 15 for pumping the liquid developer from the supply pot 14, the peripheral surface of the pumping roller 15 and the surface 6 a of the developing roller 6, An application roller 16 that applies the liquid developer pumped by the pumping roller 15 to the surface 6 a of the developing roller 6 is provided.

  The scooping roller 15 enters the supply pot 14 and is immersed in the liquid developer stored in the supply pot 14. The liquid developer in the supply pot 14 has high wettability. Therefore, the liquid developer is drawn up by the rotation of the pumping roller 15 and is carried on the surface 6 a of the developing roller 6 through the application roller 16. The rotation direction of the developing roller 6 (the direction indicated by the arrow 17) is opposite to the rotation direction 9 of the photosensitive drum 2. Since the surface 6a of the developing roller 6 and the surface 2a of the photosensitive drum 2 are in contact with each other, the liquid developer carried on the surface 6a of the developing roller 6 is supplied to the surface 2a of the photosensitive drum 2, As a result, the electrostatic latent image is developed on the surface 2 a of the photosensitive drum 2. The developing roller 6 is provided with a liquid developer removing device 18 for removing the liquid developer remaining on the surface 6 a of the developing roller 6 after developing the electrostatic latent image on the surface of the photosensitive drum 2.

  The liquid developer removing device 18 is in contact with the surface 6a of the developing roller 6 and has a cleaning blade 19 for stripping off the liquid developer remaining on the surface 6a of the developing roller 6 and an elliptical cross section. The liquid developer peeled off by 19 is scraped out and moved to a recovery position 21 of a recovery device 20 described later, and the liquid developer moved by the rotation of the sweep roller 22 is guided to the recovery position 21. And a guide 23.

The collection device 20 is disposed on the side of the sweep roller 22 and collects the liquid developer moved by the sweep roller 22, and has a substantially L-shaped cross section opened toward the sweep roller 22 side. 30 and a collection conveyance member 31 disposed at a collection position 21 partitioned by the frame 30.
In the liquid developing device 1 of this embodiment, the liquid developer removed from the surface 6a of the developing roller 6 by the liquid developer removing device 18 is recycled without being discarded. More specifically, a blending pot 35 for storing the liquid developer supplied to the supply pot 14 while adjusting the components is connected to the supply pot 14 via a supply path 36, and the surface 6 a of the developing roller 6. The liquid developer removed from the liquid is supplied to the blending pot 35 through the collection path 37. In addition to the recovered liquid developer removed from the surface 6 a of the developing roller 6, a new concentrated liquid developer and carrier liquid are given to the blending pot 35. The recovered liquid developer, the new concentrated liquid developer and the carrier liquid are mixed and the components are adjusted, and then supplied again to the developing roller 6 to be used for developing the electrostatic latent image.

FIGS. 3 and 4 are diagrams showing how the liquid developer is removed from the surface 6 a of the developing roller 6 using the liquid developer removing device 18. The configurations of the liquid developer removing device 1 and the collecting device 20 will be described with reference to FIGS.
The cleaning blade 19 is a plate member made of polyurethane, and is arranged in a posture inclined slightly from the position extending in the tangential direction of the developing roller 6 so that the end surface faces the developing roller 6. Further, the cleaning blade 19 is disposed so as to be inclined obliquely with respect to the horizontal plane so as to be lowered downward from the front end portion 24 toward the rear.

  The sweep roller 22 is a hard roller made of polycarbonate, for example. The sweep roller 22 also rotates about a rotation shaft 27 extending in parallel with the rotation shaft of the developing roller 6 in a direction opposite to the rotation direction of the developing roller 6. The sweep roller 22 having an elliptical cross section is arranged on the upstream side of the tip of the cleaning blade 19 so that the long axis end 26 is closest to the developing roller 6. Since the sweep roller 22 is for removing the liquid developer peeled off from the developing roller 6 by the cleaning blade 19, in order to remove the liquid developer efficiently, the long axis end 26 of the sweep roller 22 is removed. It is desirable that the rotation trajectory is close to the cleaning blade 19 as long as it does not overlap the cleaning blade 19. Further, the liquid developer peeled off from the developing roller 6 by the cleaning blade 19 often accumulates in the vicinity of the front end portion 24 of the cleaning blade 19. Therefore, the sweep roller 22 is disposed so as to be closest to the surface of the developing roller 6 upstream of the tip of the cleaning blade 19. In addition, although the roller made from polycarbonate was mentioned as an example, polyacetal etc. can be illustrated in addition.

  The guide 23 is in the form of a film having a thickness of, for example, about 125 μm, has flexibility, and can be easily deformed only by applying a light force. The thickness of the guide 23 is preferably in the range of 100 μm to 200 μm. One side 28 of the guide 23 is fixed to a frame 30 described later, and the other side 29 is lightly pressed against the tip 24 of the cleaning blade 19. The length and arrangement position of the guide 23 are determined so that the tip of the guide 23 does not protrude upstream from the tip of the cleaning blade 19.

  The frame 30 of the collection device 20 extends in the axial direction of the rotation shaft 27 of the developing roller 6 and is formed by bending a sheet metal, and a horizontal plate portion 32 arranged almost horizontally and the horizontal plate portion 32. A vertical plate portion 33 extending perpendicular to the plate portion 32 is provided. The horizontal plate portion 32 is at substantially the same height as the tip portion 24 of the cleaning blade 19. One side 28 of the above-described guide 23 is fixed to the upper surface of the horizontal plate portion 32. Since the other side 29 of the guide 23 is lightly pressed against the tip 24 of the cleaning blade 19, the guide 23 extends substantially horizontally. The shortest distance A (FIG. 3A) between the guide 23 and the rotation shaft 27 (rotation center) of the sweep roller 22 in a state where the guide 23 is stretched between the collection position 21 and the tip 24 of the cleaning blade 19. Is set shorter than the semi-long diameter B of the sweep roller 22 (the distance between the rotation center and the long axis end 26; see FIG. 3A).

The collection conveyance member 31 is configured by, for example, a spiral shaft. When the liquid developer is moved to the collection position 21 by the sweep roller 22 while the spiral shaft is in a rotating state, the liquid developer is forcibly conveyed to the collection path 38 by the action of the spiral shaft in the rotating state. Is done.
With reference to FIG. 3 and FIG. 4, how the liquid developer is removed from the surface 6 a of the developing roller 6 using the liquid developer removing device 18 will be described.

  The semi-short diameter of the sweep roller 22 (the distance between the rotation axis of the sweep roller 22 and the short-axis end of the sweep roller 22) is set to about one third of the semi-long diameter B, for example. In addition, the liquid developer has a higher toner particle content ratio than the liquid developer at the time of supply, and has a high concentration, high viscosity, and poor flowability due to the influence of heat and the like during development. Therefore, when the long axis end 26 of the sweep roller 22 is not approaching, the liquid developer removed by the cleaning blade 19 is deposited near the tip 24 of the cleaning blade 19 (see FIG. 3A). From this state, when the sweep roller 22 rotates and the long shaft end 26 reaches the position closest to the developing roller 6 (see FIG. 3B), the deposit of liquid developer is destroyed and some of the deposits are broken. The liquid developer is scraped off. As described above, since the shortest distance A between the rotation axis of the sweep roller 22 and the guide 23 is shorter than the semi-major axis B of the sweep roller 22, when the rotation of the sweep roller 22 further proceeds, the major axis end 26 of the sweep roller 22 It comes into contact with the guide 23 (see FIG. 4A). Since the guide 23 is in the form of a film and has flexibility, the guide 23 is deformed by being in contact with the sweep roller 22. As the guide 23 is deformed, the other side 29 pressed against the cleaning blade 19 is swung relatively well. For this reason, vibration can be applied to the liquid developer to be deposited on the tip 24 of the cleaning blade 19, and deposition of the liquid developer on the cleaning blade is prevented. The sweep roller 22 scrapes off the scraped liquid developer, and the liquid developer is moved toward the collection position 21 on the guide 23. It is desirable that the semi-minor axis of the sweep roller 22 is set to, for example, about one-third to one-fourth of the semi-major axis B.

When the rotation of the sweep roller 22 further proceeds (see FIG. 4B), the liquid developer is moved to the collection position 21 by the sweep roller 22. The liquid developer moved to the collection position 21 is forcibly conveyed to the collection path 37 by the collection conveyance member 31.
As described above, according to this embodiment, the film-shaped guide 23 is stretched between the collection position 21 and the tip 24 of the cleaning blade 19, and the liquid developer peeled off by the cleaning blade 19 is Instead of moving on the cleaning blade 19, it moves on the guide 23 and is guided to the collection position 21. The liquid developer is guided to the removal position on the guide 23 while being pushed by the sweep roller 22 that moves while closely contacting the guide 23. Therefore, the liquid developer removed by the cleaning blade 19 can be efficiently moved to the collection position 21. Thereby, the collection efficiency of the liquid developing device 1 is improved.

  In addition, various design changes can be made within the scope of matters described in the claims.

1 is a schematic diagram illustrating a configuration of a main part of an image forming apparatus to which a liquid developing device according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram illustrating a configuration of a liquid developing device. It is a figure which shows a mode that a liquid developer is removed from the surface of a developing roller using a liquid developer removal apparatus. It is a figure which shows a mode that a liquid developer is removed from the surface of a developing roller using a liquid developer removal apparatus.

Explanation of symbols

1 Liquid Developing Device 6 Developing Roller (Liquid Developer Carrier)
6a surface 18 liquid developer removing device 19 cleaning blade 20 collecting device 21 collecting position (removing position)
22 Sweep roller (rotating body)
23 Guide 24 Tip 27 Rotating shaft 28 One side 29 Other side A Shortest distance B Half major axis

Claims (5)

A liquid developer removing device that removes liquid developer remaining on a surface of a drum-shaped liquid developer carrying member and moves the drum to a predetermined removal position,
A cleaning blade that comes into contact with the surface of the liquid developer carrier and strips off the liquid developer remaining on the surface of the liquid developer carrier;
It has an elliptical cross section, rotates about the rotation axis extending in parallel with the rotation axis of the liquid developer carrier, and rotates in the direction opposite to the rotation direction of the liquid developer carrier, and is peeled off by the cleaning blade. A rotating body that scrapes off the liquid developer and moves it toward the removal position;
It is a film-like material, has flexibility, is stretched between the removal position and the tip of the cleaning blade, and moves the liquid developer moved by the rotating body to the predetermined removal position. A guide to guide,
A liquid developer removing apparatus comprising:   The guide is disposed such that the shortest distance from the rotation axis of the rotating body is shorter than the semi-major axis of the rotating body, and guides the liquid developer moved by the rotating body while deforming. The liquid developer removing apparatus according to claim 1.   3. The liquid developer removing apparatus according to claim 1, wherein one side of the guide is fixed at the removal position and the other side is lightly pressed against the cleaning blade.   4. The rotating body according to claim 1, wherein the rotating body is disposed so as to be closest to the surface of the liquid developer carrier on the upstream side of the tip of the cleaning blade. Liquid developer removing device. A drum-shaped developing roller carrying a liquid developer and supplying the liquid developer to the photoreceptor;
A liquid developer removing device for removing the liquid developer remaining on the surface of the developing roller;
A recovery device for recovering the liquid developer removed by the liquid developer removing device to a recovery path for recycling;
5. A liquid developing device, wherein the liquid developer removing device according to claim 1 is used as the liquid developer removing device.

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