JPH10268650A - Device and method for image formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent image having a sufficient image density without causing fogging, by sufficiently supplying only a part on an image carrier, where an electrostatic latent image is formed, with ink at the time of forming an ink image by supplying the electrostatic latent image formed on the image carrier with the ink. SOLUTION: This image forming device is provided with a latent image forming means 2 forming the electrostatic latent image on the surface of the image carrier 1, a releasing agent applying means 3 applying releasing agent 32 to the surface of the image carrier where the electrostatic latent image is formed, an ink developing means 4 forming the ink image corresponding to the electrostatic latent image by bringing the ink 42 held on the surface of an ink carrier 41 into contact with the surface of the image carrier coated with the releasing agent and a transferring means 6 transferring the ink image formed on the surface of the image carrier to a recording medium. In this case, the ink whose viscosity is in the range of 1×10<3> -1×10<6> centipoise is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method for forming an electrostatic latent image on an image carrier and developing the latent image to form an image on a recording medium. In particular, an image forming apparatus and an image forming apparatus which supplies ink to an electrostatic latent image formed on an image carrier to form an ink image, and transfers the ink image to a recording medium to form an image. It relates to a forming method.

[0002]

2. Description of the Related Art Conventionally, as typified by an electrophotographic copying machine, an electrostatic latent image is formed on the surface of an image carrier, and after developing the electrostatic latent image, the electrostatic latent image is formed on a recording medium such as paper. 2. Description of the Related Art An image forming apparatus that transfers an image onto a recording medium and forms an image on a recording medium is used.

As one of such electrophotographic image forming apparatuses, colored resin particles (toner particles) are used to develop an electrostatic latent image as disclosed in Japanese Patent Application Laid-Open No. 7-271107. One using a liquid developer dispersed in a carrier liquid is known.

Here, the liquid developer used in the electrophotographic apparatus is generally one in which charged toner particles are dispersed in an insulating carrier liquid, and the toner particles become liquid developer as an image is formed. When this liquid developer is used, it is necessary to control the concentration of the toner particles in the carrier liquid, and the management is troublesome, and most of the carrier liquid is used. Since the liquid developer is used repeatedly, there is a problem that the liquid developer is easily deteriorated.

Further, in an electrophotographic apparatus using such a liquid developer, when an image is formed on a recording medium such as copy paper, a fixing device for fixing a toner image transferred onto the recording medium or the like is used. Is required, and there is a problem that the apparatus becomes complicated and large.

[0006] Conventionally, Japanese Patent Publication No. 52-45
As shown in Japanese Patent No. 494, an ink is supplied to an electrostatic latent image formed on an image carrier to form an ink image, and the ink image is transferred onto a recording medium, and an image is formed on the recording medium. What has been proposed to be formed has been proposed.

Here, when an ink image is formed by supplying ink to the electrostatic latent image formed on the image carrier as described above, the ink is applied to a portion of the image carrier where the electrostatic latent image is not formed. Is supplied, the formed image is fogged, the ink is not sufficiently supplied to the portion where the electrostatic latent image is formed, the density of the formed image is reduced, and white spots are generated. There was a problem.

[0008]

According to the present invention, an ink image is formed by supplying ink to an electrostatic latent image formed on an image carrier, and the ink image is formed on a recording medium such as paper or an OHP sheet. It is an object of the present invention to solve the above-described problem when an image is formed on a recording medium by transferring the image.

That is, in the present invention, when ink is supplied to the electrostatic latent image formed on the image carrier to form an ink image, ink is also supplied to a portion where the electrostatic latent image is not formed. As a result, the image formed on the recording medium is not fogged, and the ink on the portion where the electrostatic latent image is formed is not sufficiently supplied. It is an object of the present invention to stably form a good image having a sufficient image density on a recording medium without lowering or causing white spots or the like.

[0010]

In the image forming apparatus according to the first aspect of the present invention, in order to solve the above-mentioned problems, a latent image forming means for forming an electrostatic latent image on a surface of an image carrier is provided. And a release material applying means for applying a release material to the surface of the image carrier on which the electrostatic latent image is formed, and applying the ink held on the surface of the ink carrier to the surface of the image carrier on which the release material is applied. An image forming apparatus comprising: an ink developing unit configured to form an ink image corresponding to an electrostatic latent image by contacting the image forming apparatus; and a transfer unit configured to transfer the ink image formed on the surface of the image carrier to a recording medium. 1 × 10 ³ to 1 viscosity as ink
The ink used was in the range of × 10 ⁶ centipoise.

In the image forming method according to a second aspect of the present invention, in order to solve the above-mentioned problems, a step of forming an electrostatic latent image on the surface of the image carrier, and A step of applying a release material on the surface of the formed image carrier, and contacting the ink held on the surface of the ink carrier with the surface of the image carrier on which the release material is applied, corresponding to an electrostatic latent image An image forming method comprising: a step of forming an ink image; and a step of transferring the ink image formed on the surface of the image carrier to a recording medium, wherein the ink has a viscosity of 1 ×
The ink used was in the range of 10 ³ to 1 × 10 ⁶ centipoise.

The viscosity of the above ink was measured using an E-type viscometer (VISCONIC ED type, manufactured by Tokyo Keiki Co., Ltd.).
Under measurement conditions of 0.5 rpm and 25 ° C., less than 20,000 centipoise is 1.34 ° × R24 cone, 0.5 rpm, 25 rpm.
It is a value measured under measurement conditions of ° C.

Here, when the ink held on the surface of the ink carrier as described above is brought into contact with the surface of the image carrier on which the release material is applied, an ink image corresponding to an electrostatic latent image is formed. If the viscosity of the ink used is too low, the ink tends to separate from the surface of the ink carrier, adheres to the surface of the image carrier on which the electrostatic latent image is not formed, and causes the image formed on the recording medium While fogging is likely to occur, if the viscosity of the ink used is too high, the ink does not easily separate from the surface of the ink carrier, and the ink is sufficiently supplied to the portion of the electrostatic latent image formed on the surface of the image carrier. And the density of the image formed on the recording medium is reduced, and white spots and the like easily occur.

As in the image forming apparatus and the image forming method according to the present invention, the viscosity is 1 × 10 ³ to 1 × 10 ^6.
When centipoise (cp) ink is used, the ink held on the surface of the ink carrier is brought into contact with the surface of the image carrier on which the release material is applied to form an ink image corresponding to an electrostatic latent image. In addition, it is possible to suppress the ink from adhering to the surface of the image carrier on which the electrostatic latent image is not formed, to suppress the occurrence of fogging on the image formed on the recording medium, and to prevent the ink from being carried on the image carrier. Is sufficiently supplied to the portion of the electrostatic latent image formed on the surface of the recording medium, and the density of the image formed on the recording medium is reduced, and the occurrence of white spots and the like is suppressed. A good image having an appropriate image density can be obtained.

When an ink image corresponding to an electrostatic latent image is formed on the surface of the image carrier using the above-described ink, the moving speed of the image carrier and the contact between the ink carrier and the image carrier. If the nip width is different, the optimum viscosity of the ink used changes, and the moving speed of the image carrier is fast, or if the nip width where the ink carrier and the image carrier come into contact is narrow, It is preferable to use the ink having the lower viscosity in the ink having the viscosity range as described above, and conversely, when the moving speed of the image carrier is slow, or when the nip width where the ink carrier and the image carrier are in contact is wide. It is preferable to use an ink having a higher viscosity in an ink having the above-mentioned viscosity range.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an image forming apparatus and an image forming method according to the present invention will be specifically described below with reference to the accompanying drawings.

In the image forming apparatus and the image forming method according to this embodiment, as shown in FIG.
As the latent image forming means 2 for forming an electrostatic latent image on the surface of the image carrier 1 while using a cylindrical conductive member 1a having a dielectric layer 1b formed on the surface thereof, Using the discharge electrode 2 formed in a multi-stylus,
Discharge was performed from the discharge electrode 2 to form an electrostatic latent image on the surface of the image carrier 1.

Here, the image carrier 1 may be of any type as long as a dielectric layer 1b is formed on a conductive member 1a, and its shape is not particularly limited. Instead, for example, the shape may be a drum shape or a film shape.

The material constituting the conductive member 1a of the image carrier 1 is, for example, aluminum,
Iron, copper, nickel, SUS, gold, silver, chromium, platinum,
In addition to metals such as tin and titanium and alloy materials thereof, a material in which these conductive materials are dispersed in a resin or the like can be used. When the conductive material is dispersed in the resin as described above, the resin may be polyethylene, polypropylene, polyvinyl alcohol, polyvinyl acetate,
Use ethylene-vinyl acetate copolymer, polymethyl methacrylate, polycarbonate, polystyrene, acrylonitrile-methyl acrylate copolymer, acrylonitrile-butadiene-styrene copolymer, polyterephthalate ethylene, polyurethane elastomer, polyamide, polyimide, etc. be able to.

On the other hand, the material constituting the dielectric layer 1b provided on the conductive member 1a is, for example, polyester, polypropylene, polyvinyl alcohol, polyvinyl acetate, ethylene-vinyl acetate copolymer, polymethacrylic acid. Methyl, polycarbonate, polystyrene, acrylonitrile-methyl acrylate copolymer, acrylonitrile-butadiene-styrene copolymer, polyterephthalate ethylene, polyurethane elastomer, viscose rayon, cellulose nitrate, cellulose acetate, cellulose triacetate, cellulose propionate, Cellulose acetate butyrate, regenerated cellulose, ethyl cellulose, polyamide (nylon 6, nylon 66, nylon 11, nylon 12, nylon 46, etc.), polyimide, polysulfone,
Polyether sulfone, polyvinyl chloride, vinyl chloride
Vinyl acetate copolymer, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinyl nitrile rubber alloy,
Inorganic materials such as resins such as polytetrafluoroethylene, polychlorofluoroethylene, polyvinyl fluoride, and polyvinylidene fluoride, and ceramics such as Al ₂ O ₃ , SiO ₂ and TiO ₂ can be used. May be used in combination of two or more.

Further, the latent image forming means 2 for forming an electrostatic latent image on the surface of the image carrier 1 may be one which can form an electrostatic latent image by selectively charging the surface of the image carrier 1. If not limited to the above, various means can be used.
For example, a latent image forming means of an ion flow type in which a photosensitive member is exposed by an exposure means and discharge is performed from the photosensitive member may be used.

When an electrostatic latent image is formed on the image carrier 1 by the latent image forming means 2 as described above, if the surface potential of the electrostatic latent image is low, the ink 42 May not be sufficiently supplied, and an image having a sufficient image density may not be obtained. Conversely, if the surface potential of the electrostatic latent image is too high, white spots or the like may occur in a formed image portion. For this reason, it is preferable that the surface potential in the electrostatic latent image portion be in the range of 200 to 2000 V in absolute value.

In this embodiment, a release material 32 is applied to the surface of the image carrier 1 on which the electrostatic latent image has been formed in a predetermined thickness by the release material applying means 3.
Thereafter, the ink 42 held on the surface of the ink carrier 41 in the ink developing means 4 is brought into contact with the surface of the image carrier 1 on which the release material 32 is applied, and the static electricity formed on the surface of the image carrier 1 is formed. The ink 42 was applied to the portion of the latent image.

Here, the release material 32 is applied to the surface of the image carrier 1 on which the electrostatic latent image is formed as described above from the release material applying means 3.
In applying, when the amount of the release material 32 applied to the surface of the image carrier 1 is small, when the ink 42 held on the surface of the ink carrier 41 is brought into contact with the surface of the image carrier 1, The ink 4 is also applied to the portion where the electrostatic latent image is not formed.
In addition, fogging is likely to occur in the image formed by the application of No. 2, and when the amount of the release material 32 applied is too large, the ink 42 is not supplied well to the portion where the electrostatic latent image is formed. In addition, there is a possibility that an appropriate image cannot be obtained due to a decrease in the density of the formed image. Therefore, when the release material 32 is applied to the surface of the image carrier 1, the thickness of the release material 32 on the surface of the image carrier 1 is 0.1 to 1
It is preferable to apply the coating so as to be in a range of 0 μm.

Although a known material can be used as the release material 32, in this embodiment, the silicone oil 32 is used as the release material 32 from the viewpoint of easy handling.

When the silicone oil 32 is applied to the surface of the image carrier 1 by the release material applying means 3, the oil application roller 31 is applied to the silicone oil 32.
The oil application roller 31 is rotated, and the amount of the silicone oil 32 on the surface of the oil application roller 31 is regulated by an oil regulating blade 33. The silicone oil 32 was applied to the surface of the image carrier 1 on which the image was formed, with an appropriate thickness.

As described above, the silicone oil 32
When the ink 42 held on the surface of the ink carrier 41 is brought into contact with the surface of the image carrier 1 on which is applied, and the ink 42 is supplied to the portion where the electrostatic latent image is formed to form an ink image, In this embodiment, the viscosity is 1 × 10 ³ to
Using the ink 42 in the range of 1 × 10 ⁶ cp, the thickness of the ink 42 on the surface of the ink carrier 41 was adjusted by any conventionally known means using a regulating blade or the like.

Here, regarding the thickness of the ink 42 on the surface of the ink carrier 41, the supply of the ink 42 to the portion of the image carrier 1 where no electrostatic latent image is formed is suppressed, In order to supply a sufficient amount of the ink 42 to the portion where the latent image is formed, the thickness of the ink 42 on the surface of the ink carrier 41 is set to 1 to
It is preferable to adjust so as to be in the range of 50 μm.

The ink 2 having the above viscosity range
Is rotated, and the ink 42 held on the ink carrier 41 is brought into contact with the surface of the image carrier 1 on which the silicone oil 32 is applied.
The ink 42 is hardly supplied to the portion of the image carrier 1 where the electrostatic latent image is not formed, and the ink 42 is sufficiently supplied to the portion where the electrostatic latent image is formed.
Then, an ink image corresponding to the electrostatic latent image was formed.

Here, the ink 42 used in this embodiment has a viscosity of 1 × 10 ³ to 1 × as described above.
The ink may be in the range of 10 ⁶ cp. For example, an ink 42 composed of a coloring material represented by a printing ink, a vehicle, and additives added as needed can be used. Among the inks for use, lithographic inks used for lithographic printing are preferably used, and oil-based inks are particularly preferable.

As the coloring material, various known coloring agents such as pigments can be used. For example, carbon black or the like is used as a black pigment, yellow iron oxide or the like is used as a yellow pigment, and red pigment is used as a red pigment. Lake Red C, Brilliant Carmine 6B, Rhodamine 6GPTMA Toner, Bengara and the like, and as the blue pigment, navy blue, ultramarine and the like are used.

As the vehicle, oils, resins, solvents, plasticizers and the like are used. As the oils, in addition to vegetable oils such as linseed oil and cinnamon oil, processing oils and mineral oils are used. Synthetic resins such as rosin-modified phenolic resins,
Natural resins such as Gilsonite, natural resin derivatives, etc. are used as solvents, and high-boiling petroleum solvents such as tetradecane and pentadecane are used. An agent may be added.

The additives which are added to the ink 42 as necessary include waxes such as plant wax, animal wax, mineral wax, synthetic wax, etc., and dryers such as metal soap and organic acid.
Surfactants such as lecithin and sorbitan fatty acid esters,
Gelling agents such as hydrogenated castor oil and aluminum soap.

The ink 42 preferably has a high resistance. Specifically, the ink 42 has a volume resistance of 1 × 10 ⁸ Ω.
・ It is preferably at least cm. The upper limit of the volume resistance value is not particularly limited, but it is sufficient if it is about 1 × 10 ¹⁴ Ω · cm. The concentration of the solid content contained in the ink 42 is preferably about 30 to 50% by weight based on the total weight of the ink 42.

Here, when the ink 42 held on the ink carrier 41 is brought into contact with the surface of the image carrier 1 on which the release material 32 is applied as described above, the electrostatic latent Although the details of the principle that the ink 42 is not supplied to the portion where the image is not formed and the ink 42 is supplied only to the portion where the electrostatic latent image is formed are not clear, the present inventors have described the following. I guess so. (1) First, the layer of the ink 42 held on the surface by the ink carrier 41 approaches the image carrier 1 on which the release material 32 is applied, and the layer of the ink 42 on the surface of the ink carrier 41 is It contacts the layer of release material 32 on the surface. (2) Here, in the image portion where the electrostatic latent image is formed, the charge on the surface of the image carrier 1 passes through the layer of the release material 32 on the image carrier 1, and the image is carried on the surface of the ink 42. A charge having a polarity opposite to the charge on the surface of the body 1 is induced. Therefore, the layer of the ink 42 receives electrostatic attraction, is attracted to the image carrier 1 side, moves so as to push away the layer of the release material 32, and adheres to the surface of the image carrier 1. At this time, not only the color material moves, but also each component of the ink 42 moves integrally. (3) When the ink carrier 41 moves away from the image carrier 1 and the interval between them exceeds a predetermined value, the adhesive force between the layer of the ink 42 in the image area and the image carrier 1 decreases. It exceeds the cohesive force, is cut to a predetermined thickness, and remains on the release material 32 side to form an image. (4) On the other hand, the layer of the ink 42 in the non-image area
Since the cohesive force is larger than that of the second layer, the release material 32
Is cut to a predetermined thickness, and the layer of the ink 42 is pulled back to the ink carrier 41 without transferring to the image carrier 1 side.

The viscosity is 1 × 10 ³ to 1 × 10 ⁶ c
When the ink 42 in the range of p is used, the layer of the ink 42 in the image portion reaches the image carrier 1 as described above, and the adhesive force between the layer of the ink 42 in the image portion and the image carrier 1 is reduced. The layer of the ink 42 is cut to a predetermined thickness by exceeding the cohesive force of the ink 42 and remains on the image carrier 1 to form an image, while the layer of the ink 42 in the non-image portion is coagulated from the layer of the release material 32. Since the force is large, only the layer of the release material 32 is cut at a predetermined thickness, and the layer of the ink 1 is pulled back to the ink carrier 41 without transferring to the image carrier 1 side. In the area where no image is formed, ink 4
2 is hardly supplied, and the ink 42 is satisfactorily supplied only to the portion where the electrostatic latent image is formed, so that an ink image is formed.

When the ink 42 is supplied from the ink carrier 41 to the image carrier 1 to form an ink image corresponding to the electrostatic latent image, the ink carrier 41 is moved relative to the image carrier 1. If you make contact by pressing firmly, fogging is likely to occur in the formed image,
It is preferable that the ink carrier 41 is brought into contact with the image carrier 1 without applying a strong pressure.

Next, the ink image formed on the surface of the image carrier 1 as described above is transferred to the recording medium 7 by the transfer means 6.
When the transfer paper 7 is transferred onto the transfer paper 7, the transfer paper 7 stored in the paper feed tray 71 is fed by the paper feed roller 72, and the transfer paper 7 is transferred to the image carrier on which the ink image is formed as described above. The ink image formed on the surface of the image carrier 1 by the transfer roller 6 is transferred onto the transfer paper 7 by pressure.

The transfer paper 7 on which the ink image has been transferred in this manner is conveyed by a conveyance belt 73 and discharged to a discharge tray 74, while the ink 42 remaining on the surface of the image carrier 1 after the transfer is removed. The toner is removed from the surface of the image carrier 1 by the cleaning device 5, and thereafter, the charge removing charger 8 is used.
As a result, the surface of the image carrier 1 is neutralized, and the above operation is repeated.

In this manner, a good image having sufficient image density on the transfer paper 7 and suppressing occurrence of fog could be formed.

(Experimental Examples 1 to 3) In these experimental examples, the image carrier 1 was made of a conductive member 1a made of an aluminum drum and formed of a polyamide resin on the surface.
While a dielectric layer 1b having a thickness of .mu.m is used, a discharge is performed using a multi-stylus discharge electrode using a 50 .mu.m copper wire as a discharge electrode 2, and the surface potential of the image carrier 1 is about An -800 V electrostatic latent image was formed.

When the silicone oil 32 is applied from the oil application roller 31 to the surface of the image carrier 1 on which the electrostatic latent image is formed as described above, the silicone oil 32 has a viscosity of 96.6 cp. Using an oil (manufactured by Dow Corning Toray Silicone Co., Ltd .: silicone oil SH200), this silicone oil 32 was applied to the surface of the image carrier 1 so as to have a thickness of about 1 μm.

On the other hand, as the ink 42, a lithographic printing ink (manufactured by T & K TOKA: Best Cure OL)
SD 797 Black M) with viscosity modifier (T & K TOK)
A company: NO. 2 ML (Resiurcer), and the viscosity was adjusted to 100 to 12,000 as shown in Tables 1 to 3 below.
Using each ink 42 in the range of 00 cp, each ink 4
2 is applied to the surface of the ink carrier 41 by about 10 μm.
m.

The nip width between the ink carrier 41 holding the ink 42 and the image carrier 1 coated with the silicone oil 32 is 1.5 mm, and the nip width between the ink carrier 41 and the image carrier 1 is The contact pressure was adjusted so as to be 0.3 kg / cm, and the developing speed was set to 40 mm / s in Experimental Example 1 shown in Table 1, and the developing speed was increased in Experimental Example 2 shown in Table 2. 150 mm /
In Experimental Example 3 shown in Table 3, the developing speed was set to 260 mm / s, and the ink carrier 41 was applied to the surface of the image carrier 1 on which the silicone oil 32 was applied.
The ink 42 held on the surface of the image carrier 1 was contacted to form an ink image on the surface of the image carrier 1.

Each ink image thus formed on the surface of the image carrier 1 was transferred onto the transfer paper 7 by the transfer roller 6 as described above, and the formed image was evaluated. The contact pressure between the transfer roller 6 and the image carrier 1 was set to a linear pressure of 1 kg / cm.

In evaluating the image formed on the transfer paper 7, the image densities in the image portion and the non-image portion are measured using a reflection densitometer (Sakura Densitometer PDA65), respectively. The image density difference (contrast) between the image portion and the non-image portion was determined, and the results are shown in Tables 1 to 3 below.

As a comprehensive evaluation, a case where a good image in which the above-mentioned contrast is 0.8 or more and the image density of the non-image portion is less than 0.3 is obtained, and a contrast is 0.45 or more and 0 0.8 and the image density of the non-image portion is 0.8.
When there is no practical problem when the image density of the non-image portion is less than 0.5 or less than 0.8 and the image density of the non-image portion is 0.3 or more but less than 0.5, If there is a problem on the image with.
-3 are shown.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

As is apparent from these results, when the viscosity of the ink 42 is low, the image density in the non-image area is high, and the formed image is easily fogged. When the viscosity is high, the image density in the image area is low, and an image having a sufficient image density cannot be obtained. As the ink 42, the viscosity is in the range of 1000 to 1,000,000 cp,
It has been found that it is desirable to use the ink 42 preferably in the range of 5,000 to 400,000 cp, more preferably in the range of 10,000 to 100,000 cp.

When the results of Experimental Examples 1 to 3 were compared, in the case of Experimental Example 1 in which the developing speed was as low as 40 mm / s, the optimum viscosity of the ink 42 was higher. On the other hand, development speed is 260m
In the case of Experimental Example 3 as fast as m / s, the optimum viscosity of the ink 42 was low, and it was preferable to change the viscosity of the ink 42 used according to the developing speed.

[0053]

As described in detail above, in the image forming apparatus and the image forming method according to the present invention, the release material is applied to the surface of the image carrier on which the electrostatic latent image is formed, and the release material is applied. When the ink held on the surface of the ink carrier is brought into contact with the surface of the image carrier to form an ink image corresponding to the electrostatic latent image on the surface of the image carrier, the ink has a viscosity of 1 × 10 ^Since the ink in the range of ³ to 1 × 10 ⁶ cp is used, it is possible to prevent the ink from adhering to the surface of the image carrier on which the electrostatic latent image is not formed, and to reduce the amount of the image carrier. Ink has been sufficiently supplied to the portion of the electrostatic latent image formed on the surface.

As a result, according to the image forming apparatus and the image forming method of the present invention, almost no ink is supplied to the surface of the image carrier on which the electrostatic latent image is not formed as described above, The ink is sufficiently supplied only to the portion of the electrostatic latent image formed on the recording medium to form an ink image. When the ink image is transferred to a recording medium to form an image, the image is formed on the recording medium. Fogging rarely occurs in an image to be formed, and a good image having a sufficient image density can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of an image forming apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image carrier 2 latent image forming means (discharge electrode) 3 release material applying means 32 release material (silicone oil) 4 ink developing means 41 ink carrier 42 ink 6 transfer means (transfer roller) 7 recording medium (transfer paper)

Claims (2)

[Claims] 1. A latent image forming means for forming an electrostatic latent image on a surface of an image carrier, a release material applying means for applying a release material to a surface of the image carrier on which the electrostatic latent image is formed, and an ink. An ink developing means for forming an ink image corresponding to the electrostatic latent image by bringing the ink held on the surface of the carrier into contact with the surface of the image carrier on which the release material is applied; and an ink developing means formed on the surface of the image carrier. And a transfer means for transferring the ink image to a recording medium, wherein the ink has a viscosity of 1 × 10 ³ to
An image forming apparatus using an ink in a range of 1 × 10 ⁶ centipoise. 2. A step of forming an electrostatic latent image on the surface of the image carrier, a step of applying a release material to the surface of the image carrier on which the electrostatic latent image is formed, and a step of holding the image on the surface of the ink carrier. Contacting the applied ink with the surface of the image carrier on which the release material has been applied to form an ink image corresponding to the electrostatic latent image, and transferring the ink image formed on the surface of the image carrier to a recording medium And d) using an ink having a viscosity in the range of 1 × 10 ³ to 1 × 10 ⁶ centipoise as said ink.