JP2000238272A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stable ink flying even with a low electric field strength as well as to provide a constant ink flying amount. SOLUTION: This image forming apparatus comprises an ink carrying roller 30 with minute recess parts 40 on the outer peripheral surface facing a photosensitive drum filled with a conductive ink. A predetermined voltage with a polarity different from that of an electrostatic latent image on the photosensitive drum is applied on the inner surface of the recess parts 40. A small hole 42 allowing passage of only air is provided on the bottom wall of the recess parts 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for flying conductive ink on an ink carrier in accordance with an electrostatic latent image on a latent image carrier or a recording voltage applied to a recording electrode, and recording the flying ink. The present invention relates to an image forming apparatus that forms an image by indirectly or directly adhering to a medium.

[0002]

2. Description of the Related Art Conventionally, ink is transferred from a thin conductive ink layer formed on an ink carrier to an electrostatic latent image on a latent image carrier by Coulomb force and developed. 2. Description of the Related Art A device that forms an image by transferring an ink image onto a recording medium such as paper is known.

[0003]

In this type of image forming apparatus, if the amount of ink flying from the ink carrier to the latent image carrier varies, it is impossible to form an image of stable image quality. Also, if the electric field strength required for flying ink is high, a large power supply device for forming this electric field must be used.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of printing a conductive ink on an ink carrier with an electrostatic latent image on a latent image carrier or a recording voltage applied to a recording electrode. In an image forming apparatus that forms an image by indirectly or directly attaching the flying ink to a recording medium, a large number of minute concave portions in which the conductive ink is filled on the surface of the ink carrier are formed. A predetermined voltage having a polarity different from that of the electrostatic latent image or the recording voltage is applied to the conductive inner wall of the recess, and a small hole through which only air can enter and exit is provided on the wall of the recess. It is characterized by.

In the image forming apparatus of the present invention, it is preferable that the inner surface of the small hole is made of a material which repels ink.

In the image forming apparatus of the present invention, the space communicating with the small holes of the concave portion is depressurized when filling the concave portion with ink, and / or pressurized when the ink flies from the concave portion. Is also good.

Further, in the image forming apparatus of the present invention, the ink carrier may be in a belt shape.

[0008]

In the image forming apparatus of the present invention, when the conductive ink is filled in the minute recesses on the ink carrier, air in the recesses escapes through the small holes. Does not remain, and the amount of ink filled in the concave portion is always constant. The inner surface of the small hole is made of, for example, a material that repels ink, so that only the air can enter and leave the small hole, and ink does not enter.

A predetermined voltage having a polarity different from that of the electrostatic latent image or the recording voltage is applied from the inner wall of the concave portion to the ink filled in the concave portion. In this state, when the ink carrier is opposed to, for example, a grounded latent image carrier, charges having a polarity opposite to the latent image potential induced by electrostatic induction are injected into the ink in each recess. An electric field is formed between the ink in the recess into which the charge is injected and the latent image carrier, and a Coulomb force acts on the ink in the recess toward the latent image carrier by the action of the electric field. Accordingly, the ink in the concave portion rises to form a meniscus.

When the ink in the concave portion in the meniscus state faces the electrostatic latent image on the latent image carrier, the intensity of the electric field is further increased, and the Coulomb force is further increased.
As a result, the ink escapes from each recess and flies toward the electrostatic latent image. As described above, when the ink escapes from the concave portion, air flows into the concave portion through the small holes, so that a negative pressure is not generated in the concave portion, and the ink can easily fly. The flying ink is once attached to the electrostatic latent image to form an ink image and then transferred to a recording medium to form an image, or the ink droplet is directly adhered to the recording medium to form an image.

As described above, according to the image forming apparatus of the present invention, since the small holes are provided, ink can be filled without leaving air bubbles in the concave portions, so that the amount of ink in each concave portion is constant. As a result, the dots formed by the ink flying from each recess become uniform, and an image having stable image quality can be formed.

Further, by providing the small holes, it is possible to prevent a negative pressure from being generated in the concave portion when the ink escapes from the concave portion, thereby making it easy for the ink to fly, so that the electric field intensity is not so strong. Can also fly the ink. As a result, even if the potential of the electrostatic latent image or the recording voltage is lowered, stable ink flying can be realized, so that the power supply device for charging the latent image carrier or applying the recording voltage and the drive circuit system are miniaturized and simplified. Power can be saved, and the cost can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes a photosensitive drum 12 as a latent image carrier. The photosensitive drum 12 is driven to rotate in the direction of arrow a. Around the photosensitive drum 12, the photosensitive drum 1 is sequentially arranged along the rotation direction.
2, a corona charging device 14 for uniformly charging the surface of the photosensitive drum 12, and an exposure for writing an electrostatic latent image by exposing the uniformly charged surface of the photosensitive drum 12 to erase the charge of the exposed portion, thereby leaving the charge of the non-exposed portion. Device 16, an ink developing device 18 for developing the written electrostatic latent image with conductive ink, a transfer roller 20 for transferring the developed ink image to paper S as a recording medium, A cleaning device 22 for collecting ink remaining on the surface of the body drum 12,
A static eliminator 24 for erasing the electrostatic latent image is provided.

The method of writing an electrostatic latent image is not limited to an exposure method, but may be any other method, such as an ion flow method, a pyroelectric method, or a method in which a ferroelectric is polarized by heat or electricity. An electrostatic latent image may be written. Also, a large number of fine electrodes may be formed on the entire surface of the drum. These techniques are known. Further, although not shown, an ink fixing device for drying and fixing the ink image transferred to the sheet S may be provided as necessary.

As shown in FIG. 2, the ink developing device 18 includes a casing 26 having an opening facing the photosensitive drum 12. A conductive ink 28 is accommodated inside the casing 26. At the opening of the casing 26, an ink carrying roller 30 is arranged in parallel with the photosensitive drum 12 with a slight gap, and is rotatable in the direction of arrow b. The lower half of the ink carrying roller 30 is immersed in the conductive ink 28.

A seal roller 32 is provided between the upper edge 26a of the casing 26 and the ink carrying roller 30, thereby preventing ink from leaking and drying. On the other hand, on the upper edge of the casing 26 opposite to the seal roller 32 with respect to the ink carrying roller 30, a regulating blade 34 is provided with its tip end surface in contact with the outer peripheral surface of the ink carrying roller 30. Thereby, the regulating blade 34
Returns the excess ink to the ink reservoir by scrubbing the ink 28 attached to the surface of the ink carrying roller 30 with the rotation of the ink carrying roller 30, and deposits the ink in the minute concave portion on the surface of the ink carrying roller 30 as described later. It plays the role of filling in as if painted. The ink carrying roller 30
Are electrically connected to an offset power supply 38 so that a predetermined voltage having a polarity different from that of the electrostatic latent image on the photosensitive drum 12 is applied.

As shown in FIGS. 3 and 4, on the outer peripheral surface of the ink carrying roller 30, a large number of minute concave portions 40 are arranged in a matrix. Although the concave portion 40 is formed in a circular opening shape having a cylindrical internal space as illustrated, the concave portion 40 may be formed in a rectangular opening shape in which the internal space is a rectangular parallelepiped. A small hole 42 through which only air can enter and exit is provided in a bottom wall portion 41 of the concave portion 40. This small hole 4
2 communicates with the internal space of the common groove 43 that penetrates the ink carrying roller 30 in the axial direction. The internal space of the common groove 43 communicates with the atmosphere.

The ink carrying roller 30 is formed as follows. First, a large number of common grooves 43 extending in parallel with the roller axis direction are formed in the outer peripheral surface of a conductive roller (for example, a metal roller) 44 which forms the center of the ink carrying roller 30 in the roller circumferential direction by a method such as etching. Process at equal pitch. Next, the outer peripheral surface of the metal roller 44 is covered with a sheet 45 made of a material having a property of repelling ink (water-repellent when water-based ink is used). As a material of the sheet 45, a material having a surface tension of 45 dyne / cm or less is preferable. Fluoroethylene, polypropylene, ethylene tetrafluoride / ethylene copolymer, paraffin, polytetrafluoroethylene, hexatriacontan,
Propylene hexafluoride and the like. Seat 4
5 is covered in advance with a conductive film formed by a method such as vacuum deposition, and the sheet 4 is covered with the conductive film.
5 and the metal roller 4
4 is secured. Next, on the sheet 45,
A number of small holes 42 are formed at equal pitches in the roller axial direction at positions corresponding to the common grooves 43 by a method such as ion etching. The diameter of the small holes is preferably about 1 to 2 μm. Next, the outer peripheral surface of the sheet 45 is covered with the second sheet 46. This second sheet 46 may be insulating or conductive. Finally, the small holes 42 of the second sheet 46 are formed by a method such as excimer laser processing.
Is removed in a circular shape to form the recess 40.

As shown in FIGS. 5A and 5B,
A filling member 47 may be provided at a corner in the recess 40. Further, the filling member 47 may be formed as a portion of the second sheet 46. The filling member 47 allows the concave portion 40
When ink is filled in the ink, there is an effect that air bubbles hardly remain in the corners.

FIG. 6A is a partially enlarged sectional view of the surface layer when the ink carrying roller 30 is cut in the axial direction.
Each recess 40 having a cylindrical internal space has a rectangular cross section,
Moreover, they are arranged at an equal pitch p. The pitch p of the concave portions 40 is preferably about 20 to 100 μm. Also, the recess 4
The ratio a: b of the width a of 2 to the width b of the projection 42 need not necessarily be 1: 1 and may be in the range of a: b = 7: 3 to 3: 7. If the ratio of the width a of the concave portion 40 is smaller than this range, manufacturing becomes difficult, and if the ratio is large, the flying ink droplet becomes large and the resolution is reduced. Further, the depth c of the recess 40 is preferably about 10 to 100 μm. If the depth c is smaller than 10 μm,
It becomes difficult to fill the ink by applying ink to 0, and 10
This is because if it is larger than 0 μm, manufacturing becomes difficult.

The internal space of the recess 40 is not limited to a columnar or rectangular parallelepiped having a rectangular cross section as shown in FIG. 6A, but may be formed in another shape, for example, as shown in FIG. May have a semi-circular hemispherical shape, a triangular conical or pyramid-shaped cross section as shown in FIG.
As shown in FIG. 6D, the section may be a truncated cone or a truncated pyramid. As shown in FIG. 6D, when the cross-sectional shape of the concave portion 40 is a trapezoid, the width d of the bottom surface is preferably about 2 to 30 μm. Also, on the surface of the ink carrying roller 30,
Although the recesses 40 are arranged in a matrix as shown in FIG. 7A, the recesses 40 may be arranged in a staggered manner as shown in FIG. Is also good.

Next, the image forming apparatus 10 having the above configuration
Will be described. In the ink developing device 18, the ink carrying roller 30 is driven to rotate in the direction of the arrow b with its lower part immersed in the ink 28. Thus, the ink 28 is applied to the surface of the ink carrying roller 3 as shown in FIG.
As shown in (2), the surplus ink 28 is scraped by the regulating blade 34 in contact with the ink carrying roller 30 and returns to the ink reservoir, and only the recess 40 is filled with ink. When the ink is filled, the air in the concave portion 40
Through the common groove 43, no air bubbles remain in the concave portions 40, and the amount of ink filled in each concave portion 40 becomes constant. On the other hand, since the inner surface of the small hole 42 is made of a material that repels ink, the ink filled in the concave portion 40 does not enter the small hole 42.

As shown in FIG. 8, the regulating blade 3
4, a pressure reducing device 4 for slightly reducing the internal space of the common groove 43 of the ink carrying roller 30.
8 may be provided. However, the amount of pressure reduction by the pressure reducing device 48 is set to such an extent that the ink in the concave portion 40 is not drawn into the small holes 42. If the pressure reducing device 48 is provided, the air in the concave portion 40 can be easily evacuated through the small holes 42 at the time of ink filling, and the effect of preventing bubbles from remaining can be further secured.

A predetermined positive voltage is applied to the ink filled in each recess 40 of the ink carrying roller 30 by an offset power supply 38 via a metal roller 44 and a sheet 45 forming the bottom surface of the recess 40. When the ink carrying roller 30 faces the grounded photosensitive drum 12 in this state, as shown in FIG. 9, a charge having a polarity opposite to that of the latent image potential induced by electrostatic induction, that is, a plus charge, is applied to each concave portion 40.
Is injected into the ink inside. An electric field is formed between the ink in the recess 40 into which the charge has been injected and the photosensitive drum 12,
The Coulomb force in the direction toward the photosensitive drum 12 acts on the ink in the concave portion 40 by the action of the electric field, whereby the ink in the concave portion 40 rises and the meniscus 52 is formed.

When the ink in the concave portion 40 in the meniscus state faces the negatively charged electrostatic latent image on the photosensitive drum 12, the intensity of the electric field is further increased and the Coulomb force is further increased. As a result, the ink escapes from each recess 40 and tries to fly toward the electrostatic latent image. At this time, if there is no small hole 42 at the bottom of the concave portion 40 as shown in FIG. 10B, a negative pressure is generated in the concave portion 40 when the ink 28 tries to escape.
Is difficult to fly. On the other hand, in the present embodiment, FIG.
As shown in (a), when the ink 28 escapes from the concave portion 40, air flows into the concave portion 40 from the common groove 43 through the small hole 42, so that a negative pressure is not generated in the concave portion 40, 28 becomes easier to fly. The flying ink once adheres to the electrostatic latent image on the photosensitive drum 12 to form an ink image, and is then transferred to the sheet S to form an image.
As described above, in the image forming apparatus 10 of the present embodiment, the ink flying from the ink carrying roller 30 is
2, the ink transferred from the ink carrying roller 30 is indirectly adhered to the paper S to form an image, such that the ink image is transferred to the paper S after the ink image is formed by being once adhered to the paper 2. .

As described above, according to the image forming apparatus 10 of the present embodiment, since the small holes 42 are provided, ink can be filled in the concave portions 40 without leaving air bubbles. Becomes constant. As a result, the size of the dots formed by the ink flying from each recess 40 becomes uniform, and an image of stable image quality can be formed.

Further, by providing the small holes 42, it is possible to prevent a negative pressure from being generated in the concave portion 40 when the ink escapes from the concave portion, thereby making it easy for the ink to fly. The ink can fly without it. As a result, stable ink flying can be realized even if the potential of the electrostatic latent image is lowered, so that the power supply device and the drive circuit system for the charging device 14 can be reduced in size, simplified, and power-saving. Cost can be reduced.

As shown in FIG. 10A, the common groove 43 of the ink carrying roller 30 is located in the ink flying area.
A pressurizing device 49 for slightly pressurizing the internal space may be provided. However, the amount of pressurization by the pressurizing device 49 is set to such an extent that the ink does not jump out of the concave portion 40 by itself. If the above-described pressurizing device 49 is provided, the concave portion 40 is formed through the small hole 42.
Since the inside is pressurized and the ink flies so as to be pushed out, the ink flies more easily, and stable ink flying can be realized even at a low electric field strength.

Next, an image forming apparatus 60 according to another embodiment of the present invention will be described with reference to FIGS.
In the image forming apparatus 10 described above, an image is formed by indirectly adhering the ink droplets flying from the ink carrying roller 30 to the paper S. However, the image forming apparatus 60 according to the present embodiment uses the ink droplets flying from the ink carrying roller 30. Is attached directly to the sheet S to form an image. For this purpose, in the image forming apparatus 60, as shown in FIG.
Is conveyed while being in contact with the photosensitive drum 12. The other configuration is almost the same as that of the image forming apparatus 10, but the ink does not adhere to the photosensitive drum 12, so that the cleaning device 22 can be omitted. Further, in order to improve the adhesion of the sheet S to the photosensitive drum 12, a pair of adhesion rollers 62 and 64 may be provided as needed.

The ink flying principle in the image forming apparatus 60 is the same as that described above with reference to FIGS. As shown in FIG. 12, the ink that has flown from the concave portion 40 on the ink carrying roller 30 toward the latent image portion of the photosensitive drum 12 directly adheres to the sheet S to form an image. Also according to the image forming apparatus 60 of the present embodiment,
The same effects as those of the image forming apparatus 10 can be obtained.

Next, an image forming apparatus 70 according to still another embodiment of the present invention will be described with reference to FIGS. In this image forming apparatus 70, as shown in FIG.
Of the ink carrying roller 30. The sheet S is transported in the direction of the arrow while contacting the lower part of the recording electrode 72. As shown in FIG. 14, the recording electrode 72 includes a number of individual electrodes 74 arranged at regular intervals in a direction perpendicular to the sheet conveying direction, and a protective insulating portion 7 surrounding the individual electrodes 74.
6. The individual electrodes 74 are arranged at a density corresponding to the pixel density of an image, and each end portion has a recording electrode 72.
At the bottom of the sheet S. Each of the individual electrodes 74 is connected to a power supply 80 via a switch 78. The switch 78 is selectively turned on in accordance with image information, so that a negative polarity recording voltage is applied to the individual electrode 74 at a position where ink is to fly. Although the configuration of the recording electrode 72 is illustrated in FIG. 14, the recording electrode 72 is not limited to this mode, and a multi-stylus electrode of another mode may be used.

The principle of flying ink in the image forming apparatus 70 is the same as that in the image forming apparatus 60. However, the photosensitive drum 12 is replaced by the recording electrode 72,
The latent image portion having a negative charge is merely replaced with the individual electrode 74 to which a negative polarity recording voltage is applied. When a recording voltage is applied to the individual electrode 74, the ink flies from the concave portion 40 of the ink carrying roller 30 facing the recording voltage,
This ink directly adheres to the sheet S to form an image.
As described above, also in the image forming apparatus 70 of the present embodiment, the same effects as those of the image forming apparatus 10 can be obtained.

In each of the image forming apparatuses 10, 60 and 70 described above, the roller 30 is used as an ink carrier.
However, as shown in FIG. 15, the ink carrying belt 5 having the same surface layer structure as the ink carrying roller 30 is used.
0 may be used for the ink developing device 18a.

Here, an ink flying experiment was performed by the image forming apparatus shown in FIG. 15 using the ink carrying belt 50. The conditions at that time were as follows. An OPC photosensitive drum is used as the photosensitive drum 12, the charging potential of the photosensitive drum 12 (that is, the potential of the electrostatic latent image) is -300 volts, and the developing speed (that is, the peripheral speed of the photosensitive drum) is 200 mm. / Sec. The ink carrying belt 50 is
As shown in FIG. 16, a common groove 43 having a width of 10 μm and a depth of 5 μm is etched at an interval of 10 μm to a thickness of 300 μm.
m aluminum sheet 50a and a 5 μm thick polyethylene terephthalate sheet 50b in which aluminum is vacuum-deposited over the entire surface and small holes 42 having a diameter of 2 μm are formed in a matrix of 20 μm pitch by 20 μm by ion etching.
And a 10 μm-thick polyimide sheet 50 c formed by excimer laser processing into a 10 μm-diameter through-hole 40 a serving as the concave portion 40 in a matrix having a pitch of 20 μm vertically and horizontally. Therefore, the diameter of the concave portion 40 of the ink carrying belt 50 is 10 μm, and the pitch p of the concave portion 40 is
Is 20 μm in both the belt rotation direction and the direction perpendicular thereto, and the depth of the concave portion 40 is 10 μm.
Further, the peripheral speed of the ink carrying belt 50 is set to 200 mm / sec.
c. Further, by connecting the aluminum sheet 50a of the ink carrying belt 50 to the offset power supply 38, the ink filled in each concave portion 40 is applied with 1.5 kV through the aluminum-deposited polyethylene terephthalate sheet 50b.
Voltage was applied. Further, the developing gap g (the distance between the photosensitive drum 12 and the ink carrying belt 50) was set to 500 μm. The composition of the conductive ink 28 used is carbon black (black), chromophthal yellow (yellow), quinacridone magenta (magenta), or copper phthalocyanine blue (cyan).
Is 10 wt% and water is 86.99 w
t%, 0.01% of a fluorine-based surfactant as a surfactant
wt%, polyethylene glycol 1 as viscosity modifier
wt%, 2 wt% of styrene acrylate as dispersant
And Experiments under these conditions showed that the ink flew well against the electrostatic latent image. Further, the diameter of the dots formed by the flying ink was almost constant.

On the other hand, in a comparative experiment, the ink carrying belt 50 was not provided with the small holes 42, and other conditions were the same as those in the above experiment. As a result, the ink hardly flew to the electrostatic latent image. In addition, the diameter of the dots formed by the flying ink also varied. Thus, according to the image forming apparatus of the present invention,
It was confirmed that stable ink jetting can be realized with a low electric field strength, and that a dot of a uniform size can be formed with a constant ink jetting amount.

In the above description, the polarity of the electrostatic latent image or the recording voltage has been described as minus. On the contrary, the present invention is applicable to the case where the polarity of the electrostatic latent image or the recording voltage is plus. can do.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of an ink developing device.

FIG. 3 is a partially enlarged view of an end of an ink carrying roller.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIGS. 5A and 5B are partially enlarged cross-sectional views showing a modification in which a filling member is provided at a corner in a concave portion.

FIG. 6 is a partially enlarged cross-sectional view of a surface layer when the ink carrying roller is cut in the axial direction.

FIG. 7 is a partially enlarged plan view showing an arrangement pattern of concave portions on the ink carrying roller.

FIG. 8 is a partially enlarged cross-sectional view showing a state where ink is filled in a concave portion on the ink carrying roller.

FIG. 9 is a partially enlarged cross-sectional view showing a state in which a meniscus is formed in the ink in the concave portion of the ink carrying roller when facing the photosensitive drum.

FIG. 10 is a partially enlarged view showing a state in which ink flies from a concave portion, where (a) shows a case where there is a small hole;
(B) shows a case where there is no small hole.

FIG. 11 is a schematic configuration diagram of an image forming apparatus according to another embodiment of the present invention.

FIG. 12 is a partially enlarged cross-sectional view showing a state in which ink flying from a concave portion on an ink carrying roller is directly attached to a sheet.

FIG. 13 is a schematic configuration diagram of an image forming apparatus according to still another embodiment of the present invention.

FIG. 14 is a partially enlarged view of a recording electrode.

FIG. 15 is a schematic configuration diagram of an image forming apparatus showing a modification using a belt as an ink carrier.

FIG. 16 is an exploded partial enlarged view of an ink carrying belt used in an ink flying experiment.

[Explanation of symbols]

10 image forming apparatus, 12 photosensitive drum (latent image carrier), 30 ink carrier roller (ink carrier), 38
... Offset power supply, 40 ... Concave part, 42 ... Small hole, 43 ... Common groove.

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[Procedure amendment]

[Submission date] November 30, 1999 (1999.11.
30)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

FIG. 6A is a partially enlarged sectional view of the surface layer when the ink carrying roller 30 is cut in the axial direction.
Each recess 40 having a cylindrical internal space has a rectangular cross section,
Moreover, they are arranged at an equal pitch p. The pitch p of the concave portions 40 is preferably about 20 to 100 μm. Also, the recess 4
The ratio a: b between the width a of 0 and the width b between the concave portions 40 does not necessarily need to be 1: 1, but may be in the range of a: b = 7: 3 to 3: 7. If the ratio of the width a of the concave portion 40 is smaller than this range, manufacturing becomes difficult, and if the ratio is large, the flying ink droplet becomes large and the resolution is reduced. Further, the depth c of the recess 40 is preferably about 10 to 100 μm. If the depth c is smaller than 10 μm,
It becomes difficult to fill the ink by applying ink to 0, and 10
This is because if it is larger than 0 μm, manufacturing becomes difficult.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

Next, the image forming apparatus 10 having the above configuration
Will be described. In the ink developing device 18, the ink carrying roller 30 is driven to rotate in the direction of the arrow b with its lower part immersed in the ink 28. As a result, the ink 28 is applied to the surface of the ink carrying roller 30, but as shown in FIG. 8, the excess ink 28 is scraped off by the regulating blade 34 in contact with the ink carrying roller 30 and returns to the ink pool, and the concave portion is formed. Only inside 40 is filled with ink. When the ink is filled, the air in the concave portion 40
Through the common groove 43, no air bubbles remain in the concave portions 40, and the amount of ink filled in each concave portion 40 becomes constant. On the other hand, since the inner surface of the small hole 42 is made of a material that repels ink, the ink filled in the concave portion 40 does not enter the small hole 42.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (4)

[Claims] 1. A method according to claim 1, wherein the conductive ink on the ink carrier is caused to fly in accordance with an electrostatic latent image on the latent image carrier or a recording voltage applied to a recording electrode, and the flying ink is indirectly or directly applied to a recording medium. In an image forming apparatus for forming an image by attaching an image, a plurality of minute concave portions filled with the conductive ink are formed on the surface of the ink carrier, and the electrostatic latent image is formed on a conductive inner wall of the concave portion. Alternatively, an image forming apparatus is characterized in that a predetermined voltage having a polarity different from the recording voltage is applied, and a small hole through which only air can enter and exit is provided in the wall of the concave portion. 2. The image forming apparatus according to claim 1, wherein the inner surface of the small hole is made of a material that repels ink. 3. The space according to claim 1, wherein the space in which the small holes communicate with each other is depressurized when filling the ink into the concave portion and / or pressurized when flying the ink from the concave portion. Image forming device. 4. The image forming apparatus according to claim 1, wherein said ink carrier has a belt shape.