JPH0418308B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an apparatus for developing electrostatic images obtained by electrophotography and electrostatic recording, and more particularly to a wet type developing apparatus. In the present invention, the electrophotographic method and the electrostatic recording method are collectively referred to as the electrophotographic method.

[Conventional technology]

Microphotographic cameras using a wet development method for electrophotography are known today. For example, Japanese Patent Application Publication No. 1973-
It is described in No. 144443, No. 53-133034, No. 50-83036, and Japanese Patent Publication No. 49-33791.

[Problem to be solved by the invention]

Since these prior art techniques all use pre-prepared developing solutions, the following drawbacks are inevitable. If the toner is not used for a long period of time, the toner will aggregate and precipitate, resulting in a change in toner concentration. The resistance of the developer also changes, and therefore the photographic properties change over time. Even if it has not been used for a long time, if the amount of toner consumed is large, the toner concentration and liquid resistance will change.
The problem arises. To solve this problem, a replenisher with a high toner concentration must be supplied periodically or occasionally, which complicates the apparatus. If the developer is left unused for a long period of time, the developer dries in the nozzles and rollers, causing the toner and resin contained in the solution to stick, making maintenance difficult. Toner is electrodeposited on the developing electrode or developing head, and cleaning is required. A pump is required to stir and feed the developer, making it difficult to make the device more compact. Since the exposed area of the flammable developer to the air is large, the amount of volatilization is large, and it is necessary to actively exhaust the volatilized solvent vapor. An object of the present invention is to provide an electrophotographic developing device that solves the above-mentioned drawbacks.

[Means to solve the problem]

The present invention provides a toner release member having an electrostatic charge image holding member on which an electrostatic charge image is formed, a support member having an uneven surface formed thereon, and a toner release layer in which toner is provided in a layered manner on the support member. a liquid supply section that supplies an insulating liquid that becomes a developer when the toner is dispersed to the toner release layer; a developer formed on the toner release layer by the liquid supply section; and the electrostatic image holding member. A developing device characterized by comprising: a guide means for bringing the electrostatic charge image holding surface into contact with the developing device. The present invention also provides an electrostatic charge image holding member on which an electrostatic charge image is formed, a matte layer containing spacer particles that make the surface uneven, and a toner release layer in which toner is provided in a layer on the matte layer. a liquid supply section that supplies an insulating liquid, which becomes a developer when toner is dispersed, to the toner release layer, and a developer formed on the toner release layer by the liquid supply section and the static liquid. This developing device is characterized by comprising a guide means for bringing the charge image holding member into contact with the electrostatic charge image holding surface.

【Example】

The present invention will be explained in more detail below using the drawings. FIG. 1 shows an embodiment of the present invention.
is an electrophotographic recording material serving as an electrostatic image holding member, 1
0 is its supply roll, and 12 is its take-up roll. The electrophotographic recording material 11, as shown in FIG. a transparent photoconductive insulating layer 25 (e.g., polyvinylcarbazole, other organic pigments, etc.) (organic photoconductive layer, ZnO fine powder dispersed in a polymer binder, amorphous selenium formed by vapor deposition, CdS sputtered, and other known materials); A subbing layer, intermediate layer, overcoat layer, etc. may be provided. 13 is a known corona charger, 14 is a photographic lens, 16 is a toner discharge member, 15 is a supply roll thereof, and 17 is a take-up roll. The toner discharge member 16 has an elongated shape,
As shown in the cross section of FIG. 3, a toner release layer 28 is provided in which toner is provided in a layered manner with a conductive layer 27 interposed on a support 26 having an uneven surface. The configuration will be described in more detail later. The toner emitting member 16 is movable via a roller 22, and the roller 22 is configured to transfer the developer formed on the toner emitting layer 28 and the electrostatic image bearing surface of the electrophotographic recording material 11. It acts as a guide means for making contact only between predetermined areas. Note that a drive mechanism for the roller 22 is not shown. Reference numeral 18 denotes an insulating liquid supply tank serving as a liquid supply section, into which a porous member 19 (felt, sponge, cloth, etc.) is inserted to serve as a mechanism for sucking up the liquid in the tank. When the insulating liquid supply tank 18 is moved up and down by a drive mechanism (not shown), the porous member 19 comes into contact with the surface of the toner release layer.
Then apply an insulating liquid to the desired portion of the toner release layer. The electrophotographic recording material 11 conveyed from the supply roll 10 by a conveyance mechanism (not shown) is charged by a corona charger 13 and exposed through a photographing lens 14 to record an electrostatic charge image. The electrophotographic recording material 11 on which the electrostatic charge image has been recorded is further transferred to a roller 22.
conveyed in the direction. In the vicinity of the roller 22, the developer formed on the toner discharge member 16 comes into contact with the electrostatic image bearing surface of the electrophotographic recording material 11 to develop the electrostatic image. The electrostatic image holding surface and the toner release layer surface may be brought into contact with each other, or may be made to face each other with a small distance maintained therebetween. In short, it is sufficient that the developer for the toner release layer comes into contact with the electrostatic image holding surface. It is desirable that the circumferential speed of the roller 22 and the moving speed of the electrophotographic recording material 11 be substantially the same in size and direction in order to prevent fogging due to toner rubbing, but this is not necessary. When the toner adheres to the electrostatic image holding member and development is completed, excess liquid is removed by an appropriate method such as air squeezing (not shown), and then the toner is fixed by a fixing device. FIG. 1 shows an example of fixing using infrared rays, and this fixing device consists of two infrared lamps.
0 and its reflecting mirror 21, but any other known methods such as pressure fixing or solvent fixing by coating with a spray fixer can be used. After drying and fixing, the electrophotographic recording material is wound onto a winding roll 12. FIG. 4 shows an example of a liquid supply section. The liquid supply section consists of a tank 18, a porous member 19, and an insulating liquid 30. The head of the tank 18 is tapered, and the porous member If you hold it in place, you won't have to worry about the liquid spilling even if the device is tilted.
Evaporation is also kept to a minimum. FIG. 5 shows how an electrostatic charge image formed on an electrophotographic recording material is developed. Reference numeral 11 indicates an electrophotographic recording material on which an electrostatic charge image (not shown) is formed, a support 23, a conductive layer 24, photoconductive insulating layer 2
A meniscus is formed by the developer between the photoconductive insulating layer surface, which serves as the electrostatic charge image holding surface, and the toner release layer surface. Region A is a portion where the insulating liquid has not yet been applied to the toner release layer 28, region B is a portion where the insulating liquid has been applied but the toner is not dispersed in the liquid and does not contribute to development, and region C.
Area D indicates a portion where the toner is dispersed in the liquid to form a meniscus and development is performed, and area D indicates a portion away from the meniscus where contribution to development has ended. 45
is a thin film of the developer that adheres to the electrostatic image holding surface after development, but this dries in a short time, but as mentioned above, it may be forcibly dried by air squeezing or the like. Next, the toner discharge member, which is important in the present invention, will be explained in more detail. As shown in detail in FIGS. 3 and 5, the toner release member 16 is made of a material such as paper, polyethylene terephthalate, polycarbonate, polyamide, polyethylene, acrylic resin, etc., which has an uneven surface and is roughened. A conductive layer 2 is placed on a support 26 made of many plastic films or the like.
A toner release layer 28 is provided through the toner layer 7 . In this embodiment, the surface of the support is roughened, and the conductive layer 27 is also roughened in accordance with the shape of the surface of the support. Furthermore, the toner release layer 28 is also provided on an uneven surface that is almost the same as the roughened surface of the support, but the toner release layer 28 is provided so that the valley portions of the toner release layer 28 are thicker than the peak portions. Toner release layer 28
The depth of the valley or the height of the peak is about 2 to about 100μ, preferably about 3 to 75μ, more preferably about 4 to about
50μ, and the average distance from one peak to the next or from one valley to the next is about 2 to about 500μ, preferably about 3 to 250μ, more preferably about 4 to about 100μ.
is within the range of All conventionally known methods for forming an uneven surface on the surface of the support can be used. For example, plastic may be poured over a rough metal band and peeled off after solidification. The composition of the toner release layer 28 may be formed by evaporating the carrier liquid of a known developer. Commonly known developers are carbon black and other organic or inorganic pigments dispersed in organic solvents.
The carrier liquid is generally an insulating, odorless, non-toxic purified isoparaffinic hydrocarbon having a boiling point of 120 to 200°C. Silicone oil, halogenated hydrocarbons, etc. may also be used if cost is ignored. As mentioned above, the toner particles as pigments are fine particles for ease of dispersion and have uniform chargeability, and alkyd resin, which is used as an additive in the carrier liquid to make the electrical characteristics uniform, is also used. Charge control agents such as linseed oil and metal soap, fixing agents, and surfactants are used as necessary. To make the toner release layer 28, on the support,
A conductive layer may be provided, and a coating liquid having an appropriate viscosity obtained by adding the above-mentioned appropriate solvent to a formulation corresponding to the solid content of a known developer may be applied and dried. Alternatively, a toner may be electrodeposited on the conductive layer using a known developer and dried. In order for the toner release layer 28 composed in this manner to maintain a certain degree of mechanical strength in a dry state, a binder is required to bind the toner particles together. The binder can be either or both of the above-mentioned dispersion stabilizer and charge control agent, but may be used separately. It is desirable that this binder dissolves quickly in the insulating liquid. This is because, otherwise, the development speed will be low. In addition, a conductive layer provided on the support surface of the toner emitting member is used as a developing electrode, and toner charged to the opposite polarity is attached to the electrostatic image formed on the electrostatic image holding surface to perform positive development. Reversal development can be performed by attaching toner charged to the same polarity and applying a bias voltage in a direction in which the toner is driven toward the electrostatic image bearing surface. Furthermore, by applying a bias voltage that is the same polarity as the electrostatic charge image and lower than this to the toner charged to the opposite polarity to the electrostatic charge image, a part of the toner is attracted to the developing electrode side, and a fog-free image is created. You can also get Providing a conductive layer as a developing electrode on the toner emitting layer is effective in improving continuous gradation and forming a solid black image, but it is not necessary to provide it. In addition, electrostatic recording paper is used as an electrophotographic recording material,
The so-called electrostatic recording method, in which a high voltage is applied to electrodes made of metal contacts on the dielectric layer to form electrostatic charge images with various patterns or arrangements, can be applied to the present invention. Further, the present invention can also be applied to a transfer method in which an electrophotographic recording material on which an electrostatic latent image is formed is developed and then transferred to a transfer medium (for example, plain paper) to obtain an image. As described above, according to this embodiment, since the developer is formed immediately before development, the various problems described in the prior art do not occur. Furthermore, since the new surface of the toner emitting layer is always provided so as to face the electrostatic image holding member, there is no fear that the developing electrode will get dirty. Furthermore, since the developer is supplied as a thin liquid film, drying is quick. Furthermore, if the roller 22 is not pressed down to form a meniscus in FIG. 1, and if the member 19 is kept away from the toner release layer, there is no fear of toner sticking even if the apparatus is stopped. An additional advantage of this embodiment is that the toner release layer does not have to be very mechanically strong. That is, when spacer particles are not used, mechanical strength is required because the flat toner emitting layer comes into direct contact with other members, for example, the electrostatic image holding member, but in this example, it is protected by roughening. ,
That is not needed. In this example, by forming the support of the toner release layer on an uneven surface, the insulating liquid is sufficiently applied, and therefore a meniscus is sufficiently formed, and the toner is sufficiently dispersed in the liquid. Effects such as increased image density and shorter development time can be obtained. Furthermore, as an additional feature of this embodiment, there is no fear that the spacer particles themselves will adhere to the image surface, compared to a toner release layer mixed with spacer particles for the same purpose.
In addition, compared to the irregularities formed by spacer particles, a support with a roughened surface can form extremely fine irregularities, which has the effect of improving resolution, especially when developing minute images such as microphotographs. have FIG. 6 shows a toner ejection member for use in another embodiment of the invention. In this embodiment, the developing device has the same structure as that shown in FIG. 1 above, except for the toner emitting member, so the structure and explanation of the developing device other than this toner emitting member will be omitted. The toner release member 60 in this developing device is
A smooth support 61, a matte layer 62 containing spacer particles 65 that make the surface uneven, and a conductive layer 63.
and a toner release layer 64 in which toner is provided in layers.
spacer particles 65 on the support 61
A mat layer 62 formed into a mat by applying a solution containing
A toner release layer 6 is formed on a support 61 which has a substantially uneven surface by forming a conductive layer 63 thereon.
4 is provided. Note that the composition and manufacturing method of the toner release layer 64 are the same as known ones. FIG. 7 shows a modification of FIG. 6. In this example, the toner emitting member 70 includes the mat layer 7
2 is configured to also serve as a conductive layer, and the support body 71
An electrically conductive matte layer 72 containing spacer particles 74 that makes the surface uneven is provided thereon, and a toner release layer 73 in which toner is provided in a layered manner on the matte layer 72. . Such a matte layer 73 can be obtained, for example, by applying a conductive paint mixed with spacer particles 74. As the spacer particles 74, particles of plastic, glass, etc. can be used. It goes without saying that the same effects as in the embodiment shown in FIG. 1 can be obtained by using the toner discharge member shown in FIGS. 6 and 7. FIG. 8 shows a modification of the invention. Explanation of the components labeled with the same numbers as in FIG. 1 will be omitted. Further, charging, exposure, drying, and fixing steps are omitted. Reference numeral 33 denotes an insulating liquid supply tank serving as a liquid supply section, which moves in the direction of arrow 35 to apply an insulating liquid to the electrostatic image holding surface of the electrophotographic recording material. Reference numeral 37 indicates an area coated with an insulating liquid. The electrophotographic recording material coated with the insulating liquid is moved in the direction of the arrow by a drive mechanism (not shown). On the other hand, a toner emitting member having a toner emitting layer in which toner is provided in a layered manner comes into contact with the insulating liquid applied to the electrophotographic recording material near the roller 22. As a result, the toner in the toner release layer is dispersed in the insulating liquid and becomes a developer in the region where the meniscus 42 is formed, thereby developing the electrostatic charge image on the electrophotographic recording material. Furthermore, in FIG. 8, similar to the embodiment of FIG. 1,
An insulating liquid supply tank 32 is added for supplying an insulating liquid to the toner release layer. Movement of tank 32 in the direction of arrow 34 applies the insulating liquid to the toner release layer of the toner release member. 36
indicates an area where an insulating liquid is applied to the toner release layer. The rest is the same as the embodiment shown in FIG. 1, so a description thereof will be omitted. By applying the liquid to both the toner release layer and the electrostatic image holding surface, there is an advantage that the meniscus 42 is easily formed and the background of the image surface is less likely to be stained. It is most desirable for the above-mentioned reasons that the insulating liquid be applied to both the toner release layer and the electrostatic charge retaining surface, and then it is desirable to apply it only to the toner release layer. When applying an insulating liquid to the toner release layer,
If the coating is completed while the surface on which the electrostatic charge image is formed is being charged or exposed, there will be enough time for development to take place at the meniscus, and the toner will be released sufficiently and development will occur quickly. It has the advantage of being As the insulating liquid, those used as carrier liquids of known developers can be used, for example,
Examples include insulating hydrocarbon liquids such as Isopar H, G, and E (all manufactured by Etsuo Standard Oil Co., Ltd., trade names), kerosene, decalin, toluene, and carbon tetrachloride.

【Effect of the invention】

As described above, according to the present invention, the insulating liquid, which is a toner dispersant, and the toner are provided separately, and the developer is formed when necessary, without preparing a developer in advance. Deterioration of the liquid can be prevented, and the device configuration can be simplified. Furthermore, since fine particle toner is used, which is an advantage of the wet development method, images with high resolution and rich continuous tone reproduction can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment according to the present invention.
FIG. 2 is a cross-sectional view of the electrophotographic recording material. FIG. 3 is a sectional view of the toner release member. FIG. 4 is a sectional view showing one embodiment of the liquid supply section. FIG. 5 is an enlarged view showing an embodiment according to the present invention. FIGS. 6 and 7 are cross-sectional views of modified examples of the toner discharge member. FIG. 8 is an enlarged view showing a modification of the present invention. DESCRIPTION OF SYMBOLS 11... Electrophotographic recording material, 13... Corona charger, 16... Toner discharge member, 18... Insulating liquid supply tank, 19... Porous member, 22... Drive roller, 26... Support body, 27... Conductive layer, 28... Toner release layer, 30... Insulating liquid, 32, 33... Insulating liquid supply tank.

Claims (1)

[Scope of Claims] 1. An electrostatic image holding member on which an electrostatic image is formed;
A toner release member includes a support having an uneven surface and a toner release layer in which toner is provided in a layered manner on the support, and an insulating liquid that becomes a developer when the toner is dispersed is applied to the toner. a liquid supply section for supplying a liquid to the release layer; a guide means for bringing the developer formed on the toner release layer by the liquid supply section into contact with the electrostatic charge image holding surface of the electrostatic charge image holding member;
A developing device comprising: 2. an electrostatic charge image holding member on which an electrostatic charge image is formed;
A toner release member includes a matte layer containing spacer particles that make the surface uneven, a toner release layer in which toner is provided in a layer on the matte layer, and an insulating liquid that becomes a developer when the toner is dispersed. comprising a liquid supply section for supplying the toner release layer, and a guide means for bringing the developer formed on the toner release layer by the liquid supply section into contact with the electrostatic charge image holding surface of the electrostatic charge image holding member. A developing device characterized by: