JPH1152734A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly coat a developer carrier with a high viscosity liquid developer, with a simple constitution by uniformly arranging plural recessed parts in the surface carrying the liquid developer of the developer carrier. SOLUTION: A developing belt 45 is provided with the recessed parts 451 distributed to be independent and uniform in the carrying direction of the developing belt and a direction perpendicular to the carrying direction of the developing belt, in the surface carrying the liquid developer. In such a case, a coating roller uniformalizes the liquid developer with which the belt 45 is coated, by a uniformalizing member, so that the liquid developer with which the belt 45 is coated by the coating roller is carried in the recessed parts 451 of the belt 45. The liquid developer can be carried in the recessed parts of the belt 45. The depth of the recessed parts 451 is set according to a liquid developer quantity per unit area on the belt 45, that is, the layer thickness of a layer of the liquid developer. Thus, as the whole of the belt 45, the liquid developer can be uniformly carried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for applying a high-viscosity liquid, and more particularly to improvement of uniformity and image quality of a high-viscosity liquid applied to a liquid application target.

[0002]

2. Description of the Related Art In a developing apparatus for developing an electrostatic latent image on a latent image body using a liquid developer in which a toner is dispersed in a dielectric carrier liquid at a high concentration, a high-viscosity liquid developing apparatus uses an application roller. The developer is applied to the developer carrier in a thin layer form, and a voltage is applied to the developer carrier to transfer the liquid developer on the developer carrier to an electrostatic latent image on the latent image body, thereby forming a latent image body. The upper electrostatic latent image is being developed.

[0003]

However, in general, when a high-viscosity liquid is sandwiched between two members, and the high-viscosity liquid is attached to both members, the two members are separated and a liquid film is provided on the member surface. Irregularities occur on the liquid film surface. This is because when the highly viscous liquid is divided into two, the liquid is separated in a manner of pulling a thread, and finally the thread-like portion is cut and the portion is raised.

[0004] In a developing device for developing an electrostatic latent image on a latent image body using a high-viscosity liquid developer, similarly, the high-viscosity liquid developer is developed with the application roller side in such a manner as to draw a thread. As a result, a phenomenon occurs in which the thread-like portion is cut off and the portion swells.

[0005] When the bulge occurs on the surface of the liquid developer on the developer carrier as described above, density unevenness occurs in a portion where the density of the developed image should be uniform.

SUMMARY OF THE INVENTION The present invention has been made to solve such a disadvantage, and has as its object to uniformly apply a high-viscosity liquid developer to a developer carrier with a simple structure.

[0007]

SUMMARY OF THE INVENTION A developing device according to the present invention is a high-viscosity liquid in which toner is dispersed at a high concentration in a developer carrier having a plurality of recesses uniformly arranged on a surface for carrying a liquid developer. Apply the developer in a thin layer, contact the liquid developer on the developer carrier with the electrostatic latent image formed on the latent image body surface,
The liquid developer on the developer carrier is transferred to an electrostatic latent image on the latent image body to develop the electrostatic latent image on the latent image body.

A developing device according to another aspect of the present invention provides a high-viscosity developer in which a toner is dispersed at a high concentration on a developer carrier having a plurality of projections having a uniform height uniformly arranged on a surface for supporting a liquid developer. Liquid developer is applied in a thin layer, and the liquid developer on the developer carrier is brought into contact with the electrostatic latent image formed on the surface of the latent image body,
The liquid developer on the developer carrier is transferred to an electrostatic latent image on the latent image body to develop the electrostatic latent image on the latent image body.

Furthermore, a member for leveling the surface of the thin layer of the high-viscosity liquid formed on the surface of the developer carrying member is provided, and the amount of the high-viscosity liquid on the developer carrying member is made uniform.

Further, each of the protrusions has a width at a tip end portion wider than a width at a root portion, and has a high holding power of the liquid developer.

Further, the amount of the liquid developer on the developer carrying member is adjusted by making the concave portion or the projecting portion independent of the direction of transport of the developer carrying member or the direction orthogonal to the direction of transport of the developer carrying member. Even out.

Further, the recesses or protrusions are independently distributed in the direction of transport of the developer carrier and the direction orthogonal to the direction of transport of the developer carrier, so that the amount of the liquid developer is reduced. Make it even more above.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device according to the present invention forms a thin layer of a high-viscosity liquid developer in which toner is dispersed in a high concentration on a developer carrier to which a voltage is applied, and forms the liquid developer on the surface of a latent image body. The liquid developer on the developer carrier is brought into contact with the electrostatic latent image, and the liquid developer on the developer carrier is transferred to the electrostatic latent image on the latent image body by a voltage applied to the developer carrier. And develops the electrostatic latent image on the latent image body. In particular, by uniformly applying a high-viscosity liquid developer to the surface of a developer carrying member composed of a developing belt or a developing roller, it is possible to prevent the occurrence of shading in a portion that should have the same density after development.

The developing device has, for example, a liquid developer tank, a drawing roller, a coating roller, a leveling member, a developing belt, and two tension rollers. The liquid developer tank stores a high-viscosity liquid developer in which toner is dispersed at a high concentration in a dielectric carrier liquid. The drawing roller draws the liquid developer from the liquid developer tank. The application roller thins the liquid developer pumped from the liquid developer tank by the pumping roller and applies the liquid developer to the developing belt. The leveling member smoothes the liquid developer on the developing belt,
The height of the surface is made uniform. The developing belt has, for example, a plurality of recesses distributed on the surface carrying the liquid developer so as to be independent and even with respect to the direction of conveyance of the developing belt and the direction orthogonal to the direction of conveyance of the developing belt. The concave portion carries the liquid developer applied by the application roller. The depth of the concave portion is determined according to the amount of the liquid developer per unit area on the developing belt, that is, the thickness of the liquid developer layer. The developing belt contacts the photoreceptor while maintaining a constant tension by two tension rollers, and transfers the liquid developer carried in each concave portion to an electrostatic latent image on the photoreceptor, thereby forming a latent image on the latent image. Develop the electrostatic latent image. By carrying the liquid developer in this concave portion, the liquid developer separates into the application roller side and the developing belt side in a manner that pulls a thread, and finally the thread-like part is cut and the part swells. Even if it occurs, the amount of the liquid developer carried in the concave portions is constant, so that the liquid developer can be uniformly carried on the entire developing belt. further,
Since the liquid developer carried by the plurality of recesses distributed so as to be independent and equal to each other in two different directions is leveled by the equalizing member, the amount of the liquid developer on the developing belt is further increased. Can be even.

Here, instead of having a plurality of recesses, the developing belt is distributed, for example, so as to be independent and uniform in two different directions on the surface carrying the liquid developer, for example. A plurality of protrusions may be provided. Similar effects can be obtained even when a projection is provided instead of the recess.

As described above, by equalizing the amount of the highly viscous liquid developer on the surface of the developing belt, the electrostatic latent image on the photoreceptor can be made uniform in the image forming apparatus using the developing device of the present invention. In addition, development can be performed at an appropriate density, and it is possible to prevent shading from occurring in a portion that should have the same density after development.

[0017]

FIG. 1 is a block diagram of an image forming apparatus provided with a developing device 4 according to an embodiment of the present invention. As shown in the figure, the image forming apparatus includes a photoreceptor 1, a charging roller 2, an exposure unit 3, a developing device 4, a transfer roller 5, a cleaning blade 6, and a discharging lamp 7. The photoconductor 1 is charged by the charging roller 2 and forms an electrostatic latent image on the surface by exposure of the exposure unit 3.

The developing device 4 has a liquid developer tank 41, a drawing roller 42, a coating roller 43, a leveling member 44, a developing belt 45, and two tension rollers 46 and 47. The liquid developer tank 41 stores a high-viscosity liquid developer 90 in which a toner is dispersed at a high concentration in a dielectric carrier liquid. The drawing roller 42 draws up the liquid developer 90 from the liquid developer tank 41. The application roller 43 thins the liquid developer 90 pumped from the liquid developer tank 41 by the pumping roller 42 and applies the liquid developer 90 to the developing belt 45. The leveling member 44 leveles the liquid developer 90 on the developing belt 45 so that the surface of the developer 90 is even.

As shown in FIGS. 2 and 3, for example, the developing belt 45 is independent of the direction in which the developing belt is conveyed and the direction perpendicular to the direction in which the developing belt is conveyed. It has a plurality of recesses 451 distributed so as to be even. Since the application roller 43 smoothes the liquid developer 90 applied to the development belt 45 by the leveling member 44, the application roller 43 carries the liquid developer 90 applied to the development belt 45 by the concave portion 451 of the development belt 45, and The agent 90 can be carried by the concave portion 451 of the developing belt 45. The depth of the concave portion 451 is determined according to the amount of the liquid developer 90 per unit area on the developing belt 45, that is, the thickness of the layer of the liquid developer 90. Here, the image density of the image finally formed on the recording medium such as the recording paper 10 is determined by the layer thickness of the liquid developer 90 on the developing belt 45, the toner content of the liquid developer 90, the developing belt It varies depending on the transfer rate of the liquid developer 90 from the photoconductor 45 to the photoconductor 1 and the transfer rate of the liquid developer 90 from the photoconductor 1 to the recording paper 10 and the like. For this reason, the depth of the concave portion 451 needs to be determined according to these. As described above, the liquid developer 90 is held by the plurality of recesses 451 arranged independently and equally in two different directions, so that the liquid developer 90 is uniformly applied to the entire developing belt 45. And it is possible to prevent the occurrence of shading in a portion where the image has a uniform density because the amount of the liquid developer 90 is not uniform.

The developing belt 45 contacts the photoreceptor 1 while maintaining a constant tension by the two tension rollers 46 and 47, and the liquid developer 90 carried in each recess 451 by the voltage applied to the developing belt 45. Is transferred to an electrostatic latent image on the photoconductor 1. The developing device 4 having such a configuration can develop the electrostatic latent image on the photoreceptor 1 at an appropriate density.

The transfer roller 5 transfers the toner image on the photosensitive member 1 to the transfer paper 10 by a transfer bias. The cleaning blade 6 scrapes off the remaining liquid developer 90 from the portion of the photoconductor 1 after the transfer of the toner image. The discharge lamp 7 discharges the portion of the photoconductor 1 after the transfer of the toner image. Here, the charge removing lamp 7 may be provided upstream of the cleaning blade 6.

Here, in the above embodiment, the developing belt 45
3, a plurality of recesses 451 distributed independently and uniformly in the direction in which the developing belt 45 is transported and the direction orthogonal to the transport direction on the surface carrying the liquid developer 90 as shown in FIG. However, the concave portions 451 may be arranged diagonally as shown in FIG. Also in this case, the same effects can be obtained because the concave portions 451 are distributed independently and uniformly in the transport direction of the developing belt 45 and in the direction orthogonal to the transport direction.

Further, as shown in FIG. 5, the concave portions 451 of the developing belt 45 may be made independent and uniform in a direction perpendicular to the conveying direction of the developing belt 45. Further, the concave portions 451 of the developing belt 45 may be made independent and uniform with respect to the transport direction of the developing belt 45.

Further, instead of providing the concave portion 451 on the surface of the developing belt 45 carrying the liquid developer 90, protrusions 453 having a uniform height may be provided at equal intervals as shown in FIGS. .

Further, the developing belt 45 is shown in FIGS.
As shown in FIG. 7, a projection 453 having a wide end 454 may be provided. Thus, the holding power of the liquid developer 90 by the developing belt 45 can be increased. Further, even when foreign matter is contained in the liquid developer 90, the foreign matter can be held by the protrusion 453 and can be prevented from adhering to the photoconductor 1.

Further, the protrusion 453 of the developing belt 45
However, as shown in FIG. 10, the tip 454 may be made spherical in two different directions independently. Thereby, the liquid developer 90 on the developing belt 45 can be made more uniform.

Instead of making the tip 454 of the protrusion 453 of the developing belt 45 spherical, the contact portion with the photosensitive member 1 may be made flat.

In the above embodiment, the developing belt 45 is used as the developer carrier, but a roller may be used instead of the developing belt 45.

Instead of using a blade-like member as the leveling member 44, a roller-like member may be used.

[0030]

As described above, according to the present invention, a liquid developer is applied in a thin layer to a developer carrier having a plurality of recesses evenly arranged on a surface for supporting the liquid developer. The liquid developer can be uniformly carried on the body surface, and the liquid developer on the developer carrier is brought into contact with the electrostatic latent image formed on the latent image body surface, and the liquid developer on the developer carrier is discharged. When the electrostatic latent image on the latent image body is transferred to the electrostatic latent image on the latent image body and developed, it is possible to prevent the occurrence of shading in a portion where the image density should be uniform.

Further, a high-viscosity liquid developer in which toner is dispersed at a high concentration is formed in a thin layer on a developer carrier having a plurality of projections of uniform height uniformly arranged on a surface for supporting the liquid developer. Since the liquid developer is applied, the liquid developer can be evenly carried on the surface of the developer carrier, and the electrostatic latent image formed on the surface of the latent image body is brought into contact with the liquid developer on the developer carrier to carry the developer. Transfer the liquid developer on the body to the electrostatic latent image on the latent image body, and when developing the electrostatic latent image on the latent image body, check that the shading occurs in the area where the image density should be uniform. Can be prevented.

Further, since a member for leveling the surface of the thin layer of the high-viscosity liquid formed on the surface of the developer carrier is provided, the liquid developer on the developer carrier can be made more uniform.

Further, since the width of the tip of the projection is wider than the width of the base, the holding power of the liquid developer can be increased.

Further, since the width of the tip of the projection is wider than the width of the base, when foreign matter is contained in the liquid developer, the foreign matter is held between the projections, and the foreign matter is added to the toner image after development. Can be removed.

Further, since the recesses or projections are made independent of the direction of transport of the developer carrier or the direction orthogonal to the direction of transport of the developer carrier, the developer carrier is moved in the transport direction of the developer carrier. Alternatively, the amount of the liquid developer can be made uniform in a direction perpendicular to the transport direction of the developer carrier.

Further, since the recesses or projections are made independent of the direction of transport of the developer carrier or the direction orthogonal to the direction of transport of the developer carrier, the developer carrier is moved in the direction of transport of the developer carrier. In addition, the amount of the liquid developer can be made uniform in a direction orthogonal to the transport direction of the developer carrier.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus using a developing device of the present invention.

FIG. 2 is a sectional view of a developing belt.

FIG. 3 is a perspective view of a developing belt having independent concave portions in two different directions.

FIG. 4 is a perspective view of a developing belt provided with a concave portion that is obliquely independent of a transport direction.

FIG. 5 is a perspective view of a developing belt provided with a concave portion independent in a direction orthogonal to a transport direction.

FIG. 6 is a cross-sectional view of a developing belt having independent protrusions in a direction orthogonal to the transport direction.

FIG. 7 is a perspective view of a developing belt having independent protrusions in a direction orthogonal to the transport direction.

FIG. 8 is a cross-sectional view of a developing belt having a protruding portion having a wide tip.

FIG. 9 is a perspective view of a developing belt having a protrusion with a wide independent tip in one direction.

FIG. 10 is a perspective view of a developing belt having a spherical protrusion at the tip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Exposure unit 4 Developing device 41 Liquid developer tank 42 Pumping roller 43 Application roller 44 Equilibrium member 45 Developing belt 451 Depression 452 Convex part 453 Projection part 5 Transfer roller 6 Cleaning blade 7 Discharge lamp 90 Liquid development Agent

Claims (6)

[Claims] 1. A liquid developer having a high viscosity in which toner is dispersed at a high concentration is applied to a developer carrier in a thin layer, and the liquid developer applied to the developer carrier is formed on the surface of a latent image body. A developing device that contacts the latent image, transfers the liquid developer on the developer carrier to an electrostatic latent image on the latent image body, and develops the electrostatic latent image on the latent image body; A plurality of recesses are uniformly arranged on a surface for supporting the liquid developer. 2. A liquid developer having a high viscosity in which a toner is dispersed at a high concentration is applied to a developer carrier in a thin layer, and the liquid developer applied to the developer carrier is formed on the surface of a latent image body. A developing device that contacts the latent image, transfers the liquid developer on the developer carrier to an electrostatic latent image on the latent image body, and develops the electrostatic latent image on the latent image body; A plurality of projections having a uniform height are uniformly arranged on the surface carrying the liquid developer. 3. The apparatus according to claim 1, further comprising a member for smoothing a thin layer of a high-viscosity liquid formed on the surface of the developer carrier.
The developing device as described in the above. 4. The developing device according to claim 2, wherein each of the protrusions has a width at a tip portion wider than a width at a base portion. 5. The developing device according to claim 1, wherein the concave portion or the projecting portion is independent of a direction in which the developer carrier is transported or a direction orthogonal to the direction in which the developer carrier is transported. 6. The developing device according to claim 1, wherein the concave portion or the projecting portion is independent of a direction in which the developer carrying member is conveyed and a direction orthogonal to the direction in which the developer carrying member is conveyed.