JP2962199B2 - Image forming apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus and method used for a printer, a facsimile, a copying machine, and the like.

[0002]

2. Description of the Related Art Conventionally, as a high-resolution image forming apparatus,
Offset printing machines are widely used. Normally, image formation in offset printing is performed in the following order. First, a plate obtained by applying a hydrophobic photosensitive layer to the surface of a hydrophilic material is prepared. Next, the plate material is exposed to light carrying image information. Next, the exposed plate material is subjected to a chemical treatment to chemically remove only the non-exposed non-image portions of the photosensitive layer while leaving the exposed image portions of the photosensitive layer. A plate comprising an image portion and a hydrophilic non-image portion is formed. Next, the plate is wetted with water to attach water (fountain solution) to the hydrophilic non-image portion, and then a hydrophobic ink is applied to the plate. As a result, due to the repulsive force of the water and oil, the non-image area where the dampening water adheres repels the ink,
The ink is applied only to the image portion that is not wet with water, and an image is formed.

As described above, in the offset printing plate, since the surface state is different between the non-image portion and the image portion, blurring of the outline of the image portion does not easily occur, and a high-resolution image can be obtained. However, since the offset plate is produced by a chemical treatment, it cannot be recycled. Therefore, it is good to print a large number of copies using one plate, but when only a small number of copies are required, the cost of the plate per printed material is high and the printing cost is increased. There is.

Therefore, various methods for forming a high-resolution image without using such a non-recyclable plate have been proposed. For example, Japanese Patent Publication No. 49-4661 discloses the following image forming method. That is,
An image support having a photosensitive layer whose conductivity is changed by light is exposed to a light and dark pattern to form a pattern due to a change in conductivity, and then an electric field is applied to the image support to form a conductive pattern. An electrostatic latent image is obtained by forming a high electric field in a region where the number of the pixels increases and a low electric field in a region where the conductivity is low. The high electric field region thus formed is easily wetted by the hydrophobic liquid. Therefore, a colorless hydrophobic liquid is supplied near the image support carrying the electrostatic latent image, only the area where the high electric field is formed is wetted with the hydrophobic liquid, and then the ink composed of the colored hydrophilic liquid is supplied. Is supplied to an image support, and only a region where a low electric field is formed is wetted with ink to obtain a visible image.

Japanese Patent Laid-Open Publication No. Hei 1-208144 discloses that a hydrophilic or lipophilic liquid is adhered to an image by using an ink-jet method so as to correspond to an image. There has been disclosed an image forming method in which a latent image composed of a distribution of a lipophilic liquid is formed, and an image is formed by transferring the hydrophilic or lipophilic ink to the latent image using the latent image as an underprint.

[0006]

However, in the image forming method disclosed in Japanese Patent Publication No. 49-4661, the surface material of the high electric field region and the low electric field region on the image support are the same. Therefore, the holding power of the hydrophobic liquid and the ink is weak, and the boundary between the area wetted with the hydrophobic liquid and the area wetted with the ink is easily blurred, and the contrast between the high electric field area and the low electric field area is reduced. Without sufficient removal, image fogging often occurs and resolution is reduced.

On the other hand, in the image forming method disclosed in JP-A-1-208144, the transfer of the ink to the latent image depends on the affinity between the hydrophilic liquid for the latent image and the hydrophilic ink and the latent image. Since it depends only on the affinity between the lipophilic liquid and the lipophilic ink, poor ink transfer is likely to occur. In addition, since this method forms a latent image using an inkjet method, the resolution of the image is determined by the small diameter of the ink jet nozzle, and it is not possible to obtain a high resolution due to the restriction on the processing accuracy of the nozzle. difficult.

In view of the above problems, an object of the present invention is to provide an image forming apparatus and method capable of forming a high-resolution image.

[0009]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: an image support on which an image is supported; and a liquid supplied to the image support, the liquid being supplied onto the image support. A liquid film forming means for forming a film, and a latent image for forming a liquid latent image in a pattern with or without a liquid film on the image support by partially removing the liquid film formed on the image support The image forming apparatus further includes: a forming unit; and a developing unit configured to supply a developer whose viscosity is reduced by contact with the liquid to the liquid latent image to form an image with the developer on an image support.

In the first image forming apparatus of the present invention, the developing means supplies a developer in which a water-soluble resin, a pigment or a dye is dispersed in water to the liquid latent image. It is preferred that Further, in the first image forming apparatus of the present invention, the developing means supplies the liquid latent image with a developer whose density is decreased by contact with the liquid and whose viscosity is decreased by the decrease of the density. Alternatively, the developing means may supply the liquid latent image with a developer whose pH is changed by contact with the liquid and whose viscosity is reduced by the change of the pH.

According to a second image forming apparatus of the present invention which achieves the above object, an image support on which an image is supported, and a liquid film is formed on the image support by supplying a liquid to the image support. Liquid film forming means, and a latent image forming means for forming a liquid latent image in a pattern of the presence or absence of a liquid film on the image support by partially removing the liquid film formed on the image support, The ink in the developer is supplied to the liquid latent image by bringing a gel-like developer that contains ink and shrinks in contact with the liquid into contact with the liquid latent image, and the ink is supplied onto the image support by the ink. And developing means for forming an image.

Here, in the second image forming apparatus of the present invention, the image support moves in a predetermined direction, and the developing means carries the film-form developer and the image support is It is preferable that the image forming apparatus further includes a developer carrier that moves at the same speed as the image support in a direction in which relative sliding with the image support is prevented by coming into contact with the liquid latent image above.

Further, in the second image forming apparatus of the present invention, the developing means includes a developing agent which contracts due to a change in liquid composition due to the contact with the liquid, and which is brought into contact with the liquid latent image. The ink may be supplied to the liquid latent image to form an image with the ink on the image support, or the developing unit may include:
An ink in the developer is supplied to the liquid latent image by bringing a developer that contracts due to a change in pH due to the contact with the liquid into the liquid latent image to form an image using the ink on an image support. Further, the developing means may contact the liquid latent image with a developer that contracts due to a change in ionic composition due to contact with the liquid, thereby causing the ink in the developer to form the liquid latent image. To form an image with the ink on the image support.

In either the first image forming apparatus or the second image forming apparatus, the liquid film forming means supplies the image support with a liquid containing water as a main component as the liquid. It is preferable that
Further, in any of the first image forming apparatus and the second image forming apparatus, the latent image forming unit may include:
It is preferable that the liquid latent image is formed by irradiating a laser beam on the image support on which the liquid film is formed, or the latent image forming unit includes:
It is also a preferable embodiment that the liquid latent image is formed by partially heating the image support on which the liquid film is formed.

Here, in either the first image forming apparatus or the second image forming apparatus, a predetermined recording medium is supplied to the image support after the image is formed. It is preferable to include an image transfer unit that transfers an image formed on the image support to the recording medium.
Further, a first image forming method of the present invention for achieving the above object includes a step of supplying a liquid to an image support on which an image is supported to form a liquid film on the image support, By partially removing the formed liquid film, a step of forming a liquid latent image in a pattern with or without a liquid film on the image support, and a developer whose viscosity is reduced by contact with the liquid, Supplying the liquid latent image to form an image on the image support with the developer.

Further, the second object of the present invention to achieve the above object is as follows.
The image forming method includes supplying a liquid to an image support on which an image is supported to form a liquid film on the image support, and partially removing the liquid film formed on the image support. Forming a liquid latent image on the image support with a pattern of the presence or absence of a liquid film, and contacting a gel developer containing ink and contracting by contact with the liquid to the liquid latent image. And supplying the ink in the developer to the liquid latent image to form an image with the ink on an image support.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a schematic view illustrating a process of forming an image according to an embodiment of the present invention. As shown in FIG. 1A, a liquid that reduces the viscosity of the developer 4 by contact with a developer 4 described later (see FIG. 1C) is uniformly applied on the image support 1, The film 2 is formed. The thickness of the liquid film 2 is desirably the minimum thickness necessary for lowering the viscosity of the developer 4, and when considering the effect on the recording medium in the end, it is 10 μm or less, preferably 0.1 μm or less. The thickness is preferably about 3 μm.

To form the liquid film 2, the liquid may be applied using a roll, or after the liquid droplets are supplied onto the image support 1, the film thickness may be regulated using a blade. Good.
Next, using the latent image forming means 3, the liquid film 2 is partially removed in accordance with the image information, and as shown in FIG. Leaving the liquid film 2
The liquid film 2 in a region corresponding to the non-image portion is removed to form a liquid latent image 20 having a pattern including a region 20a where the liquid film 2 exists and a region 20b where the liquid film 2 has been removed.

As the latent image forming means 3, it is preferable to use a non-contact type thermal means such as an infrared laser.
The contact type or the non-contact type is not limited thereto, and may be a contact type or a non-contact type as long as the liquid film 2 can be removed with high definition according to an image in a short time.
An air suction head or the like can also be used. Next, FIG.
As shown in (c), the developer 4 is supplied onto the image support 1.

The developer 4 may be a developer whose viscosity is reduced by contact with the liquid constituting the liquid film 2, or alternatively, the developer 4 may contain a liquid containing ink and constituting the liquid film 2. The developer may be a gel-like developer that contracts upon contact with the developer. Details of the developer 4 will be described later. The supply of the developer 4 is performed by developing means such as a rotating roll (not shown).

When a developer whose viscosity is reduced by contact with a liquid is used, when the developer 4 is supplied onto the image support 1, the developer 4 in contact with the area 20 a where the liquid film 2 exists is provided. Only mixes with the liquid film 2 causing a decrease in viscosity,
The developer 4 having reduced viscosity is transferred onto the image support 1. In the region 20b from which the liquid film 2 has been removed, the viscosity of the developer 4 does not decrease, so that the transfer of the developer 4 to the image support 1 does not occur.

On the other hand, when the above-mentioned gel-like developer is used as the developer 4, when the developer 4 is supplied onto the image support 1, the developer in contact with the region 20a where the liquid film 2 exists is provided. Only the developer 4 contracts, the ink contained in the contracted developer 4 is released, and the released ink moves to the image support 1. In the region 20b where the liquid film has been removed,
Since the contraction of the developer 4 does not occur, the ink in the developer 4 is not released, so that the image support 1 of the ink
No transfer occurs.

As described above, since the developer 4 or the ink contained in the developer 4 does not transfer to the non-image portion, that is, the region 20b from which the liquid film has been removed, image fogging occurs. Therefore, a high-resolution image can be obtained. Thus, an image 21 is formed on the image support 1 by a film in which the liquid film 2 and the developer 4 are mixed.
As shown in FIG. 1D, the image 21 formed on the image support 1 is transferred onto the recording medium 5.

The recording medium 5 is an intermediate transfer member such as a transfer roll. The image 21 is temporarily transferred to the intermediate transfer member, and then the image transferred to the intermediate transfer member is re-transferred to recording paper. However, it is preferable to use the recording paper itself as the recording medium 5 and directly transfer the image 21 to the recording paper because the configuration of the apparatus can be simplified. Next, the developer will be described.

As described above, a developer whose viscosity is reduced by contact with another liquid may be used. The decrease in the viscosity may be caused by a chemical change. In addition, the decrease in the viscosity may be caused by a decrease in the concentration. A method utilizing the viscosity decrease due to the concentration decrease is preferable because it is simple and can form an image at high speed.

A water-based or oil-based printing ink or the like can be used as a developer whose viscosity is lowered by a decrease in concentration, but care must be taken in handling since oil-based printing inks use an organic solvent. Therefore, for example, it is preferable to use, as a developer, a material in which a water-soluble resin and a pigment or a dye are dispersed in water, such as an aqueous printing ink. In this case, it is preferable to use water or a liquid containing water as a main component as the liquid for forming the liquid latent image.

Examples of the above water-soluble resins include water-soluble resins such as starch, dextrin, alginate, cellulose ester, cellulose ether, polyvinyl alcohol, polyvinyl methyl ether, polyacrylamide, polyethylene oxide, polyacrylate, and the like. Shellac, styrenated shellac, styrene maleic resin, rosin maleic resin, casein and its derivatives, colloidal dispersions such as acrylic copolymers, and also acrylic resins, vinyl acetate resins, styrene resins, vinyl chloride resins Resin, an emulsion polymer such as synthetic rubber latex, or an emulsifying resin such as polyurethane, polyester, alkyd resin, epoxy ester, rosin ester and the like can be used alone or as a mixture.

FIG. 2 is a graph showing the relationship between the concentration of the carboxymethyl cellulose aqueous solution and the viscosity. As shown in FIG. 2, the viscosity of the aqueous carboxymethylcellulose solution rapidly decreases as the concentration decreases. Utilizing this phenomenon, a water-soluble developer, whose viscosity decreases as the concentration decreases, is brought into contact with the water film of the liquid latent image, and the viscosity of the developer in the area in contact with the water film of the liquid latent image is reduced. Thereby, the developer can be transferred to the image support.

In this example, water is used as an example of a liquid that lowers the viscosity of the developer. However, it is difficult to form a liquid film because water alone has a high surface tension. Therefore, it is preferable to use a liquid film obtained by adding a surfactant of several percent to water, because the surface tension of the liquid film decreases and the wettability to the surface of the image support increases. Surfactants include:
There are cationic, anionic, amphoteric and other ionic surfactants and nonionic surfactants, all of which are effective in reducing the surface tension of water, but among them, polyoxyethylene type, polyol Non-ionic surfactants such as a polyhydric alcohol ester type and an ethylene oxide / propylene oxide block copolymer are preferred.

The surface of the image support is preferably made of a material having high wettability with respect to water containing a surfactant as described above. Examples of such a material include metals such as aluminum, copper, stainless steel, platinum, gold, and nickel, metal oxides thereof, rubber having a surface hydrophilic treatment, glass, and a composite of metal and glass. Among them, an anodic oxide film of aluminum widely used as a plate material for offset printing is preferable. An anodic oxide film of aluminum is preferable as the surface material of the image support because it has a high holding power to water.

Further, as a developer whose viscosity is reduced by contact with a liquid film, a water-soluble resin whose viscosity changes according to a change in pH (hydrogen ion index) of an aqueous solution can be used. FIG. 3 is a graph showing the effect of pH on the relative viscosity of a 0.5% aqueous solution of sodium polyacrylate. As shown in FIG. 3, the relative viscosity of a 0.5% aqueous solution of sodium polyacrylate has a maximum value near pH 9, and the relative viscosity sharply decreases when the pH becomes higher or lower. Therefore, an aqueous solution having a pH of about 9 as a developer is used as a developer, and an acidic aqueous solution such as hydrochloric acid, sulfuric acid, or acetic acid, or an alkaline aqueous solution such as sodium hydroxide, calcium hydroxide, or an aqueous ammonia solution is used for a liquid latent image. When used as a liquid, p is brought into contact with the developer and the liquid film,
Lowering H or increasing the pH causes a decrease in the viscosity of the developer, which can be transferred to the image support as described with reference to FIG.

When utilizing such a change in viscosity due to a change in pH, it is desirable to use a chemically stable substance which is hardly corroded by acids or alkalis, such as glass, as the image support. So far, the description has been given of the developer whose viscosity is reduced by contact with the liquid that forms the liquid film 2 (see FIG. 1). The developer will be described.

This utilizes the contraction of the gel due to the phase transition caused by the contact of the gel with the liquid. That is, the gel-like developer 4 containing the ink (FIG. 1)
(C) is supplied to the liquid latent image 20 and the developer 4
Is brought into contact with the liquid film 2 in the region 20a, the gel-like developer 4 contracts, and the ink contained in the developer 4 until that time is released. For this reason, an image is formed on the image support 1 by the discharged ink. The liquid latent image 20
The thickness of the gel developer 4 supplied above is preferably as thin as possible because the speed of the phase transition is increased.

It is known that such a phase transition of the gel mainly occurs due to any of the following three factors. (1) Change in liquid composition When ethanol, methanol, acetone, or an aqueous solution thereof is brought into contact with the gel, the volume of the gel rapidly decreases. When an image is formed by utilizing the phase transition due to this phenomenon, an alcohol such as ethanol or methanol, a ketone such as acetone, an ester such as ethyl acetate, or an aqueous solution thereof is placed on the image support 1. The liquid is supplied to form a liquid film 2 on the image support 1 (see FIG. 1A). (2) Change in pH When the pH changes, the gel having an ion dissociating group undergoes a phase transition and contracts. When an image is formed by utilizing phase transition due to pH change, an acidic aqueous solution such as hydrochloric acid, sulfuric acid, or acetic acid is supplied onto the image support 1 and a liquid film 2 (see FIG. 1 (a)). (3) Change in ionic composition When an electrolyte is brought into contact with the gel, the ionic composition changes due to the effect of osmotic pressure due to the change in ionic composition, causing a phase transition of the gel.
The gel shrinks. When an image is formed by utilizing a phase transition of a gel due to a change in ionic composition, an aqueous solution of sodium chloride, calcium chloride, barium chloride or the like is used for the image support 1.
A liquid film 2 (see FIG. 1 (a)) of the aqueous solution is formed on the image support 1 by supplying it to the upper side.

An example of a phase transition of a gel due to a change in ionic composition will be described below. FIG. 4 is a graph showing the effect of the concentration of the aqueous barium chloride solution on the degree of swelling of the sodium acrylate gel. As shown in FIG. 4, when the sodium acrylate gel is brought into contact with various concentrations of barium chloride aqueous solution, the degree of swelling of the gel is greatly reduced with an aqueous solution of barium chloride having a certain ion amount or more. That is, by bringing the gel into contact with the electrolyte, the gel that has swelled up to that time can be contracted.

In order to form an image by utilizing the phase transition of the gel as described above, the above-mentioned water-soluble resin is used alone, or a crosslinking agent is added as necessary to form a three-dimensional stitch-like crosslinked structure. A gelled developer is used. Examples of the solvent of the ink contained in the gel developer include, for example, water, alcohols such as ethanol and isopropyl alcohol, hydrocarbons such as hexane and benzene, ketones such as acetone, esters such as ethyl acetate,
Ethers such as diethyl ether and amides such as dimethylformamide can be used alone or as a mixed solvent.

However, it is preferable to use water as a solvent from the viewpoint of simplicity of handling, and as the developer, use a developer in which an aqueous ink in which a dye or a pigment is dispersed in water is contained in a hydrophilic gel. Is preferred. FIG.
FIG. 1 is a sectional view of an embodiment of the image forming apparatus of the present invention. As shown in FIG. 5, the image forming apparatus 100 includes an image support 1 that supports an image and rotates in the direction of arrow A, and supplies a liquid to the image support 1 to form a liquid film on the image support 1. A liquid film forming means 7 for forming a liquid film, and irradiating a laser beam onto the image support 1 to partially remove the liquid film formed on the image support 1, thereby forming a liquid according to a pattern with or without a liquid film. A latent image forming unit 3 for forming a latent image and a developing unit 8 for forming an image on the image support 1 by developing the liquid latent image are provided.

The liquid film forming means 7 includes a liquid film forming roll 7a for forming a liquid film on the image support 1, and a liquid supply means 7b for supplying a liquid to the liquid film forming roll 7a. The liquid film forming roll 7a is made of a sponge-like material, and forms a liquid film having a uniform thickness on the image support 1 while rotating in the direction of arrow B. The developing means 8 includes a developer carrier 8 a that supplies the developer 4 to the liquid latent image and rotates in the direction of arrow C, and a developer tank 8 that holds the developer 4.
b, and a developer layer thickness regulating bar 8c for regulating the layer thickness of the developer on the developer supply roll 8a. The developer carrier 8a carries the film-form developer and contacts the image support 1 in a direction in which the developer carrier 8a comes into contact with the liquid latent image on the image support 1 to prevent relative sliding with the image support 1. It is controlled to rotate at the same peripheral speed. As a result, the liquid latent image formed on the image support 1 formed by the latent image forming means 3 and the film-like developer carried by the developer carrying member 8a rub against each other, thereby preventing the liquid latent image from being destroyed. .

The image forming apparatus 100 further includes a transfer roll 9 rotating in the direction of arrow D for transferring the image formed on the image support 1 by the developing means 8 to the recording medium 5.
A cleaning roll 10 and a cleaning blade 11 for removing the developer and liquid remaining on the image support 1 to clean the surface of the image support 1 are provided. In addition,
In the present embodiment, as shown in FIG. 5, a drum-shaped image support 1 and a roll-shaped developer carrier 8a are used, but the image support 1 is limited to only such a rotating body shape. Instead, for example, a flat image support 1 as shown in FIG. 1 may be used.

The developing means 8 does not necessarily need to include the developer carrier 8a. In short, the developing unit 8 only needs to supply the developer to the liquid latent image formed on the image support 1 to form an image on the image support 1 using the developer or ink. A process of forming an image by the image forming apparatus 100 will be described. When the surface of the image support 1 rotating in the direction of arrow A reaches a region in contact with the liquid film forming means 7, the liquid film 2 having a uniform thickness is formed on the image support 1 by the liquid film forming roll 7a (see FIG. ) Is formed.

Next, the liquid film on the image support 1 is partially removed by the latent image forming means 3, and a liquid latent image 20 (see FIG. 1 (b)) in a pattern with or without a liquid film is image-supported. Formed on the body 1. Next, an image corresponding to the liquid latent image is formed on the image support 1 by the developing means 8.

When the developing means 8 uses a developer whose viscosity is reduced by contact with the liquid film 2, when the developer 4 is supplied to the liquid latent image 20, the liquid latent image 20 Only the region 20a where the liquid film is present causes a decrease in the viscosity of the developer 4, and the developer 4 moves to the image support 1,
An image is formed on the image support 1 by the developer 4. On the other hand, when the developing means 8 uses a gel-like developer 4 containing ink and contracting by contact with the liquid film 2, the developer 4 is brought into contact with the liquid latent image 20 by The ink in the developer 4 is supplied to the liquid latent image 20, and an area 20 of the liquid latent image 20 where the liquid film exists is provided.
Only the developer 4 corresponding to “a” contracts, the ink contained in the developer 4 is transferred to the image support 1, and an image is formed on the image support 1 by the ink.

The image formed on the image support 1 by the developing means 8 is transferred to the recording medium 5 by the transfer roll 9. After the surface of the image support 1 after the transfer is cleaned by the cleaning roll 10 and the cleaning blade 11, the surface reaches the area in contact with the liquid film forming means 7 again, and the next image formation is performed.

[0044]

Next, a developer and a liquid for forming a liquid latent image will be described with reference to examples. (Example 1) As a developer, 20% by weight of a pigment, 40% by weight of water as a solvent, 28% by weight of polyvinyl alcohol as a water-soluble resin, and ethanol 5% as a dispersibility improver were used.
5% by weight of ammonia as a water-solubilizing agent and 2% by weight of a swelling clay mineral (smectite) as a thickener
Was used.

As a liquid for forming a liquid latent image, a liquid containing 2% by weight of glycerin monostearate as a surfactant in water is used, and this liquid is used as a liquid film forming means 7 (FIG. 5). (See FIG. 5), a liquid film is formed by uniformly coating the surface of the image support 1 (see FIG. 5) made of an anodized plate to a thickness of 1 μm, and a latent image forming means using a thermal head. 3 (see FIG. 5), the liquid corresponding to the non-image area was removed to form a liquid latent image.
This liquid latent image is placed on the developer carrier 8a (see FIG. 5).
The developer formed as a thin film having a thickness of μm is supplied to form an image with the developer on the image support 1, and the image is transferred to a recording medium 5 (see FIG. 5) by a transfer roll 9 (see FIG. 5). As a result, a high-resolution image was obtained in which the image portion was not crushed and the non-image portion was not fogged when the image was transferred onto the plain paper using plain paper. (Example 2) As a developer, a thin film of sodium acrylate gel was used, which was made to absorb a solution of water and a cyan dye 10: 1 until the gel could not be retained any more.

As a liquid for forming a liquid latent image, 5 ×
A ^10-3 mol / l aqueous barium chloride solution containing 2% by weight of glyceryl monostearate as a surfactant was used. This liquid is used as liquid film forming means 7
A liquid film is formed by uniformly coating the surface of the image support 1 (see FIG. 5) having a thickness of 0.5 μm using an anodized plate (see FIG. 5) to form a liquid film. The liquid corresponding to the non-image portion was removed by the latent image forming means 3 (see FIG. 5) to form a liquid latent image. When the developer formed as a thin film having a thickness of 2 μm on the developer carrier 8a (see FIG. 5) was brought into contact with the liquid latent image, the developer in contact with the liquid film contracted due to phase transition. As a result, an aqueous solution comprising water and a cyan dye in the developer was released, and an image was formed on the image support 1 using the aqueous cyan dye solution. When the image was transferred to a plain paper recording medium 5 (see FIG. 5) by the transfer roll 9 (see FIG. 5), a high-resolution image was obtained as in the first embodiment.

[0047]

As described above, according to the first image forming apparatus or the first image forming method of the present invention, a liquid latent image formed by partially removing a liquid film on an image support is formed. By supplying a developer whose viscosity is reduced by contact with the liquid constituting the liquid latent image to the image, only the developer having a reduced viscosity supplied to the area where the liquid film is present is transferred onto the image support. Therefore, the boundary between the area where the liquid film exists in the liquid latent image and the area where the liquid film has been removed is accurately reflected in the developed image, and the image area may be crushed or the non-image area may be covered. No high resolution images can be obtained.

According to the second image forming apparatus or the second image forming method of the present invention, the liquid latent image formed by partially removing the liquid film on the image support contains ink. Then, by supplying the gel developer which contracts by contact with the liquid constituting the liquid latent image, the developer is supplied to the region where the liquid film exists, and is released from the contracted developer in contact with the liquid. Since only the ink is transferred onto the image support, the boundary between the area where the liquid film exists in the liquid latent image and the area where the liquid film has been removed is accurately reflected in the image after development, and the first aspect of the present invention. Like the image forming apparatus or the first image forming method, a high-resolution image can be obtained.

As described above, according to the present invention, a high-resolution image can be formed, and there is no need to use a non-recyclable plate.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a process of image formation according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the concentration of an aqueous carboxymethyl cellulose solution and viscosity.

FIG. 3 is a graph showing the effect of pH on the relative viscosity of a 0.5% aqueous solution of sodium polyacrylate.

FIG. 4 is a graph showing the effect of the concentration of an aqueous barium chloride solution on the degree of swelling of a sodium acrylate gel.

FIG. 5 is a sectional view of an embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image support 2 Liquid film 3 Latent image forming means 4 Developer 5 Recording medium 7 Liquid film forming means 7a Liquid film forming roll 7b Liquid supply means 8 Developing means 8a Developer carrier 8b Developer tank 8c Developer layer thickness regulation Bar 9 Transfer roll 10 Cleaning roll 11 Cleaning blade 20 Liquid latent image 20a Area where liquid film 2 is present 20b Area where liquid film 2 is removed 21 Image 100 Image forming apparatus

Claims (15)

(57) [Claims] 1. An image support on which an image is supported; a liquid film forming means for supplying a liquid to the image support to form a liquid film on the image support; and a liquid film forming means formed on the image support. A latent image forming means for forming a liquid latent image in a pattern with or without a liquid film on the image support by partially removing the liquid film, and a developer whose viscosity is reduced by contact with the liquid Developing means for supplying an image to the liquid latent image to form an image with the developer on the image support. 2. The method according to claim 1, wherein the developing means comprises water, a water-soluble resin,
The image forming apparatus according to claim 1, wherein a developer in which a pigment or a dye is dispersed is supplied to the liquid latent image. 3. The liquid latent image according to claim 1, wherein the developing means supplies a developer whose density is reduced by contact with the liquid and whose viscosity is reduced by the reduced density. The image forming apparatus as described in the above. 4. The liquid latent image according to claim 1, wherein said developing means supplies a developer whose pH is changed by contact with said liquid and whose viscosity is reduced by said pH change. The image forming apparatus as described in the above. 5. An image support on which an image is supported, liquid film forming means for supplying a liquid to the image support to form a liquid film on the image support, and formed on the image support. A latent image forming means for forming a liquid latent image in a pattern of the presence or absence of a liquid film on the image support by partially removing the liquid film which has been formed; Developing means for supplying an ink in the developer to the liquid latent image by bringing a gel developer into contact with the liquid latent image to form an image with the ink on the image support; An image forming apparatus comprising: 6. The image support moves in a predetermined direction, wherein the developing means carries the film-form developer and comes into contact with a liquid latent image on the image support to form the image. 6. The image forming apparatus according to claim 5, further comprising a developer carrier that moves at the same speed as the image support in a direction in which relative sliding with the support is prevented. 7. The image forming apparatus according to claim 1, wherein the developing unit contacts the liquid latent image with a developer that contracts due to a change in liquid composition due to the contact with the liquid, thereby supplying ink in the developer to the liquid latent image, and The image forming apparatus according to claim 5, wherein an image is formed on the support by using the ink. 8. The image forming apparatus according to claim 8, wherein the developing unit contacts the liquid latent image with a developer that contracts due to a change in pH due to the contact with the liquid, thereby supplying ink in the developer to the liquid latent image to form the image. The image forming apparatus according to claim 5, wherein an image is formed on the support by using the ink. 9. The developing means supplies an ink in the developer to the liquid latent image by bringing a developer contracting due to a change in ionic composition due to the contact with the liquid into contact with the liquid latent image. 6. The image forming apparatus according to claim 5, wherein an image is formed on the image support using the ink. 10. The image forming apparatus according to claim 1, wherein the liquid film forming unit supplies a liquid containing water as a main component as the liquid to the image support. 11. The liquid image forming apparatus according to claim 1, wherein the latent image forming means forms the liquid latent image by irradiating a laser beam on the image support on which the liquid film is formed. Or the image forming apparatus according to 5. 12. The liquid image forming apparatus according to claim 1, wherein the latent image forming means forms the liquid latent image by partially heating the image support on which the liquid film is formed. Or the image forming apparatus according to 5. 13. An image transfer means for supplying a predetermined recording medium to the image support after the image has been formed, and transferring the image formed on the image support to the supplied recording medium. 6. The image forming apparatus according to claim 1, wherein: 14. A step of supplying a liquid to an image support on which an image is supported to form a liquid film on the image support, and partially removing the liquid film formed on the image support. Forming a liquid latent image on the image support according to a pattern of the presence or absence of a liquid film; and supplying a developer whose viscosity is reduced by contact with the liquid to the liquid latent image to form an image on the image support. Forming an image on the body using the developer. 15. A step of supplying a liquid to an image support supporting an image to form a liquid film on the image support, and partially removing the liquid film formed on the image support. Forming a liquid latent image on the image support according to a pattern of the presence or absence of a liquid film, and contacting the liquid latent image with a gel developer containing ink and contracting by contact with the liquid. Supplying the ink in the developer to the liquid latent image to form an image on the image support using the ink.