JPH05333703A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an ink mist system image forming device where an even image density without deteriorating efficiency of ink mist generation is obtained, soiling of ultrasonic vibrator transducer is prevented and there is no generation of ozone, etc. CONSTITUTION:Developing of an electrostatic latent image on a photosensitive drum 1 is carried out by generating the ink mist by vibrating liquid surface of liquid ink fed with an ink pump 9 by the ultrasonic vibrator body 5 which is the length equivalent to the width of the image. Furthermore, a barrier can be provided between the ultrasonic wave generator consisting of the ultrasonic vibrator body 5, etc., and the liquid ink. Moreover, the ink mist can also be generated by impressing voltage on a grid electrode 6 and an ink guide 7, etc., so that electric field is generated to have developing which is approximately perpendicular to the liquid surface. Here, an insulating material maintaining the interval between the grid electrode 6 and the photosensitive drum 1 surface and a cleaning member to clean the surface of the grid electrode 6 can be provided.

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 such as a copying machine, a facsimile or a printer, and more specifically, an image forming apparatus for forming an image by selectively adhering mist-like ink on the surface of an image carrier. It relates to the device.

[0002]

2. Description of the Related Art Image forming apparatuses such as copiers, facsimiles and printers that currently use electrophotography are
The so-called dry development method is mainly used, and an image is formed using powder toner as a coloring material. However, this dry development method has a drawback in that the toner needs to be heated and melted in order to fix the toner onto the transfer paper, and a large amount of energy is consumed at that time. In addition, there are drawbacks such as toner scattering outside the copying machine and soiling the surrounding area.
Wet development methods are under study.

Conventionally, as this type of wet developing method, liquid ink is made into mist-like ink (hereinafter referred to as ink mist) by an ultrasonic atomization method using an ultrasonic vibrator, and the ink mist is charged by corona discharge. There is known an ink mist developing method in which charged ink mist particles are prepared and the charged ink mist is used for development (for example, Japanese Patent Application Laid-Open No. Hei.
No. 125171, Electrophotography Vol. 16, No. 2 (1
977) 21-26, etc.).

[0004]

However, according to the configuration of the conventional ink mist developing system, in order to obtain an image of uniform density, the distance between the ink mist generating surface and the image forming surface is set sufficiently wide. In such a case, there is a problem that the ink mist is recombined in the meantime and the efficiency of generating the ink mist deteriorates. In addition, since the ultrasonic vibrator is located at the bottom of the ink tank and is in direct contact with the liquid ink, the ultrasonic vibrator is contaminated and requires periodic cleaning. In addition, since corona discharge is used, ozone gas is generated, and high voltage is required, which is dangerous.

The present invention has been made in view of the above problems. A first object of the present invention is to form an ink mist image in which a uniform image density can be obtained without deteriorating the generation efficiency of the ink mist. It is to provide a device. A second object is to provide an image forming apparatus capable of easily supplying ink and preventing the ultrasonic transducer from being contaminated. A third object is to provide an image forming apparatus that does not generate ozone and does not require high voltage.

[0006]

In order to achieve the above-mentioned first object, the invention of claim 1 is a mist-like ink in which a vibration generator vibrates the liquid surface of liquid ink to generate mist-like ink. In the image forming apparatus having the generating unit and the charging unit for charging the mist-like ink, the charged mist-like ink is used to develop the electrostatic latent image on the surface of the image bearing member. The vibrating body has a length corresponding to the image width on the surface of the image carrier.

In order to achieve the second object, the invention of claim 2 is to provide a mist-like ink generating means for generating a mist-like ink by vibrating the liquid surface of the liquid ink by a vibration generator, and the mist. An image forming apparatus for developing an electrostatic latent image on the surface of an image carrier using the charged mist-like ink, the charging means for charging the liquid-like ink between the vibration generator and the liquid ink. It is characterized in that a diaphragm is provided on the.

In order to achieve the third object, the invention of claim 3 is a fog-like ink generating means for vibrating the liquid surface of the liquid ink by a vibration generator to generate fog-like ink, and the fog. In an image forming apparatus for developing an electrostatic latent image on the surface of an image carrier using the charged mist-like ink.
A means for generating an electric field substantially perpendicular to the liquid surface is used in the vicinity of the liquid surface between the image carrier surface and the liquid surface of the liquid ink.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, a grid electrode is provided between the surface of the image carrier and the liquid surface of the liquid ink, and an image portion on the surface of the image carrier is formed. If the surface potential is Vl, the surface potential of the non-image area is Vd, the voltage applied to the grid electrode is Vg, and the voltage applied to the electrode on the liquid ink side is Vv, then Vv> Vg, Vd>Vg> Vl, or Vv A voltage Vg satisfying <Vg and Vd <Vg <Vl is applied to the grid electrode.

By the way, a member is abutted against the surface of the image carrier at the end of the grid electrode to substantially maintain the gap between the grid electrode and the surface of the image carrier, but the grid electrode is formed by using a thin metal plate. When the grid is formed, it is difficult to maintain the gap with high accuracy because of the flexibility of the grid electrode itself. Therefore, the invention of claim 5 is the image forming apparatus according to claim 4, wherein an insulating property is provided between the grid electrode and the image carrier surface so as to maintain a distance between the grid electrode and the image carrier surface. It is characterized in that a member is provided.

If the shape pattern of the grid electrode has a linear shape having a gravity direction component,
Contamination of the grid electrode by the liquid ink is considerably suppressed, but the components of the liquid ink dries and sticks with repeated use and adversely affects the image, and therefore it is desirable to clean the grid electrode periodically. Therefore, the invention of claim 6 is characterized in that, in the image forming apparatus of claim 4, a cleaning member for cleaning the surface of the grid electrode is provided.

[0012]

According to the image forming apparatus of claim 1, since the vibrating body of the vibration generator has a length corresponding to the image width on the surface of the image carrier, the length corresponding to the image width. A substantially uniform mist-like ink is generated over the entire area, and the vibrating body of the vibration generator can be arranged close to the image carrier surface.

According to the image forming apparatus of claim 2,
Since the diaphragm is provided between the vibration generator and the liquid ink, it is possible to vibrate the liquid surface of the liquid ink to generate atomized ink without contacting the vibration generator with the liquid ink. You can

According to the image forming apparatus of claim 3,
Since the charging means generates an electric field in the vicinity of the liquid surface between the surface of the image carrier and the liquid surface of the liquid ink, the electric field being substantially vertical to the liquid surface, so that the liquid surface of the liquid ink vibrates. When the mist-like ink is generated, the mist-like ink is charged by the charge injection.

According to the image forming apparatus of claim 4,
A grid electrode is provided between the surface of the image carrier and the surface of the liquid ink, and the predetermined voltage is applied to the grid electrode. This makes it possible to control the adhesion of the charged mist-like ink to the electrostatic latent image on the surface of the image carrier, and the charged mist-like ink moves and adheres to the image portion of the electrostatic latent image. The charged atomized ink does not move and adhere to the non-image portion.

According to the image forming apparatus of claim 5,
Even when the grid electrode is formed by using a thin metal plate, the insulating member provided between the grid electrode and the image carrier surface allows the gap between the grid electrode and the image carrier surface to be accurate. It is well maintained and the magnitude of the electric field strength in the gap during development does not change.

According to the image forming apparatus of claim 6,
By moving the cleaning member by rubbing on the surface of the grid electrode, the components of the ink dried and fixed on the surface of the grid electrode are removed, and the surface of the grid electrode is regularly cleaned.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) which is an image forming apparatus will be described below. First, an outline of the entire copying machine according to the embodiment will be described. FIG. 1 is a schematic configuration diagram of a copying machine according to this embodiment. The photoconductor drum 1, which is an image carrier, is rotating counterclockwise, is uniformly charged by the charging device 2, and is irradiated with a light image 3 corresponding to an original by an optical writing device (not shown), and the surface of the photoconductor drum 1 is kept static. A latent image is formed. This electrostatic latent image is developed in the developing device 4 with an ink mist that is mist-like ink to form a visible image. This visible image is transferred by the transfer roller 10 to a transfer paper (not shown) conveyed along the transfer paper guide 13. On the other hand, the ink slightly left on the surface of the photosensitive drum 1 is removed by the cleaning device 11 to prepare for the next charging. Here, since the charging step, the exposing step, the transferring step, and the cleaning step are not particularly characteristic, detailed description thereof will be omitted.

The developing system in this embodiment is a wet ink mist system, in which the liquid surface of the liquid ink is ultrasonically vibrated to generate an ink mist, and the ink mist is charged to give a charge to the photosensitive drum 1. The electrostatic latent image on the surface is developed. As shown in FIGS. 1 and 2,
The developing device 4 is mainly a liquid ink 17, a casing 4a of the developing device also serving as a container for the liquid ink 17, and a vibration generator of a mist-like ink generating means for vibrating the liquid surface of the liquid ink 17 to generate an ink mist. The ultrasonic wave generator, the grid electrode 6, the ink guide 7, the base 8, the ink pump 9, and the like. The ultrasonic generator is composed of the ultrasonic vibrating body 5, the ultrasonic vibrator 12, and the like. The liquid ink 17 on the bottom of the housing 4a of the developing device is pumped up by the ink pump 9 and supplied onto the ultrasonic vibrator 5.
It is held by the ink guide 7.

Next, the configuration of the ultrasonic generator according to this embodiment will be described in detail. As described above, the ultrasonic generator includes the ultrasonic vibrator 5, the ultrasonic vibrator 12, and the like. In the copying machine using the conventional ink mist system,
In order to obtain uniform image density, the distance between the ultrasonic wave generator and the surface of the photosensitive drum 1 had to be sufficient, and the ink mist was recombined between them,
The efficiency of supplying the ink mist to the surface of the photosensitive drum 1 was poor.

Therefore, in this embodiment, as shown in FIG. 2, a member having a length substantially equivalent to the image width is used as the ultrasonic vibrator 5. 3 and 5 show an example of the configuration around the ultrasonic vibrator 5 according to the present embodiment. In the configuration example of FIG. 3A, one end of the metallic ultrasonic vibrator 5 is fixed to the base 8 via the ultrasonic vibrator 12, and the other end is fixed to the base 8.
Is directly fixed to. As the ultrasonic vibrator 12, a piezoelectric material such as barium titanate having a piezoelectric effect is used for the electrode 1
What formed 2a was used. In the configuration of FIG. 3A, when an AC voltage is applied to the electrodes of the ultrasonic transducer 12,
The ultrasonic vibrator 12 expands and contracts vertically and vibrates, and this vibration is transmitted to the ultrasonic vibrating body 5 as a transverse wave, reflected at the right fixed end, and returned as a transverse wave of a reverse traveling wave. Figure 3 (c)
As shown in (1), if the standing wave is generated on the ultrasonic vibrating body 5, a large vibration amplitude can be obtained and the ink mist generation efficiency is improved. Further, in the configuration example of FIG. 3B, a thin plate-shaped metal is used as the ultrasonic vibrator 5, and the spring 13 is used to increase the propagation speed of ultrasonic vibration.
Thus, tension is applied to the ultrasonic vibrator 5. Further, in order to obtain the target standing wave, the vibration suppressing member 14 is fixed at a position serving as a node of the standing wave. When a standing wave is used as in the configuration example of FIG. 3 described above, a plurality of ultrasonic vibrating bodies 5 are arranged, and as shown in FIG. You may comprise so that the belly of a standing wave may come.

In the configuration example of FIG. 5, an ultrasonic vibrator 12 having a length substantially equal to the entire length of the ultrasonic vibrator 5 is attached between the ultrasonic vibrator 5 and the base 8. In this case,
The ultrasonic vibrator 12 itself can be used as the ultrasonic vibrator 5. In addition, a plurality of small ultrasonic transducers 12,
They may be mounted side by side between the ultrasonic vibrator 5 and the base 8.

Next, another configuration example of the developing device 4 according to this embodiment will be described. In the embodiment shown in FIG. 1, the liquid ink 17 is supplied onto the ultrasonic wave generator by using the ink pump 9, but as shown in FIG.
Liquid ink 17 is once made into an ink mist and supplied to the top plate 4b of the developing device 4 by the first ultrasonic wave generator including
The ink may be aggregated on the surface of the top plate 4b to form liquid ink, which may be supplied onto the second ultrasonic generator including the ultrasonic vibrator 5. On the other hand, if the ultrasonic oscillator 15 of the first ultrasonic generator is also attached so as to come into contact with the liquid ink 17, it may be contaminated, and the ultrasonic oscillator 15
Unlike the ultrasonic oscillator 12, it does not need to be provided inside the developing device 4.

Therefore, as shown in FIG. 6, a diaphragm 16 is provided on the bottom of the housing 4a of the developing device 4, and the ultrasonic transducer 15 is brought into contact with the lower surface of the diaphragm 16. Further, the ultrasonic vibrator 15 is fixed to the main body of the copying machine and only contacts the diaphragm 16 under the developing device 4, and the developing device 4 can be detached from the main body of the copying machine. The ultrasonic oscillator 15 vibrates the liquid surface of the liquid ink 17 to generate an ink mist. This ink mist is
It is supplied upward by the fan 14 and is condensed on the surface of the top plate 4b while the direction is changed by the fins 4c. The aggregated ink flows to the lower left along the top plate 4b, is supplied onto the second ultrasonic generator, and is made into an ink mist again.
This ink mist is used for the grid electrode 6 as described later.
And the like to be charged and charged, and the photosensitive drum 1
Used for developing electrostatic latent images on surfaces. An ultrasonic transducer 12 (not shown) is attached to the end of the ultrasonic oscillator 5 of the second ultrasonic generator. A protective film is provided on the exposed surface of the ultrasonic vibrator 12 in order to prevent contamination from ink.

Next, another configuration example of the developing device 4 according to this embodiment will be further described. As shown in FIG. 6, instead of vibrating the liquid surface of the liquid ink 17 in the developing device 4 by the first ultrasonic wave generator to generate ink mist, as shown in FIG.
You may provide the ink bottle 18 as shown in FIG. The ultrasonic vibrator 15 fixed to the main body of the copying machine is brought into contact with the bottom surface of the ink bottle 18 to vibrate the liquid surface of the liquid ink 17 in the ink bottle 18 to generate an ink mist. The bottom surface of the ink bottle 18 with which the ultrasonic transducer 15 is brought into contact is processed into a diaphragm shape in order to efficiently generate ultrasonic waves in the ink 17. In addition, the ink bottle 18
Is provided with a suction port 18a and a discharge port 18b, and air is blown from the suction port 18a by a fan (not shown) linked with the operation of the ultrasonic transducer 15, and the ink mist is supplied from the discharge port 18b into the developing device 4. It

Next, the structure of the ink mist charging means in this embodiment will be described. FIG. 8 is an explanatory diagram showing the charging of the ink mist in this embodiment. The conductive liquid ink 17 includes the ultrasonic vibrator 5 and the ink guide 7.
Is soaking. The shape of the grid electrode 6 may be a mesh shape pattern or a linear shape pattern arranged in parallel as shown in FIG. Here, the grid electrode 6
A DC power supply is connected so that Vg (V) is applied to the ink guide 7 and Vv (V) is applied to the ink guide 7. When the potential of the non-image portion (unexposed portion) of the electrostatic latent image is Vd and the potential of the image portion (exposed portion) is Vl, Vg and Vv are Vv> Vg, Vd>Vg> Vl or Vv <Vg , Vd <Vg <Vl. As a specific example of this embodiment, each voltage value is Vd = -600V, Vl = -10.
0V, Vg = -450V, Vv = -750V,
The gap Gp between the grid electrode 6 and the surface of the photosensitive drum 1 is set to 0.5 mm, and the gap Gg between the grid electrode 6 and the ink guide 7 is set to 1.0 mm. As the liquid ink 17, a suspension of carbon black having a concentration of 5 to 10 wt% is used. The ink guide 7 holds the liquid ink 17 on the surface of the ultrasonic vibrating body 5 and also serves as an electrode in the charging means of the ink mist, but the vibrating surface of the ultrasonic vibrating body 5 is electrically conductive. If processed and used as an electrode, the ink guide 7 is not always necessary.

Next, the structure of the cleaning means for the grid electrode 6 and the like will be described. As shown in FIG. 2, the grid electrode 6
If the shape pattern of the ink guide 7 is a linear shape having a component in the direction of gravity, the ink flows downward, and the contamination of the grid electrode 6 and the ink guide 7 can be considerably suppressed. It is desirable to clean it regularly because the component of (3) dries and sticks and adversely affects the image. Therefore, in the present embodiment, as shown in FIG. 9, the cleaning pad 19 is sandwiched between the grid electrode 6 and the ink guide 7 and between the ink guide 7 and the ultrasonic vibrating body 5, respectively. The cleaning pad 19 is supported by the support member 20, and is configured to move by sliding on the surfaces of the grid electrode 6, the ink guide 7, and the ultrasonic vibrator 5 by the rotation of the screw rod 21. The rotation of the screw rod 21 is driven by a motor (not shown). The movement of the cleaning pad 19 accompanied by rubbing may be performed manually.

Next, the structure of the gap holding means for the grid electrode 6 will be described. In the embodiment of FIG. 2 described above, a member (not shown) is brought into contact with the surface of the photoconductor drum 1 at the end of the grid electrode 6 so that the grid electrode 6 and the photoconductor drum 1
Although the gap with the surface is almost maintained, when the grid electrode 6 is formed by using a thin metal plate, it is difficult to maintain the gap with high accuracy due to the flexibility of the grid electrode 6 itself. .. Therefore, in this embodiment, as shown in FIG. 10, resin-made projections 22 are formed on the surface of the grid electrode 6 on the side of the photosensitive drum 1, and the projections 22 are abutted against the surface of the photosensitive drum 1. The protrusions 22 are preferably made of a resin having a high resistance so as not to disturb the electrostatic latent image, and a fluorine-based resin such as polyethylene or Teflon, nylon, polyimide or the like is suitable. It adheres to the electrode 6 surface.

As described above, according to this embodiment, the photosensitive drum 1
With the ultrasonic vibrating body 5 having a length corresponding to the image width on the surface,
Since an ink mist that is substantially uniform is generated over a length corresponding to the image width, an image with high density and uniform density can be obtained. In addition, the ultrasonic vibrating body 5 is connected to the photosensitive drum 1.
Since the ink mist can be brought closer to the surface, there is no loss of ink mist generation due to recombination of the ink mist. Therefore, the efficiency of supplying the ink mist to the surface of the photosensitive drum 1 does not deteriorate. Further, it is also advantageous for downsizing the copying machine.

Further, according to this embodiment, as shown in FIG. 6, the liquid ink 17 in the developing device 4 is brought into contact with the ultrasonic transducer 15 which is the first ultrasonic generator through the diaphragm 16. Since it is also possible to prevent the ultrasonic transducer 15 from being contaminated with the ink 17, it is possible to replace only the developing device 4 with the ultrasonic transducer 15 fixed to the main body of the copying machine. Further, as shown in FIG. 7, if the liquid ink 17 accommodating portion of the developing device 4 is configured by the ink bottle 18, the ultrasonic vibrator 15 is not contaminated with the liquid ink 17 and the liquid ink 17 is accommodated. While the developing device 4 and the ultrasonic vibrator 15 other than the parts are fixed to the main body of the copying machine,
Only the ink bottle 18 can be replaced.

Further, according to this embodiment, as shown in FIG. 8, an electric field perpendicular to the liquid surface of the liquid ink 17 is generated due to the potential difference between the voltage Vv of the ink guide 7 and the voltage Vg of the grid electrode 6. In this state, the liquid surface is vibrated to generate the ink mist, and therefore the ink mist is negatively charged by the charge injection. Therefore, it is possible to generate charged ink mist without using corona discharge,
Eliminates ozone generation and eliminates the need for high voltage. Further, by applying the voltage Vg to the predetermined grid electrode, the negative charge ink mist moves and adheres to the image portion on the surface of the photosensitive drum 1, and the negative charge is applied to the non-image portion. An electric field that prevents the ink mist from moving and adhering is formed between the surface of the photosensitive drum 1 and the grid electrode 6, and predetermined development is performed.

Further, according to the present embodiment, the surface of the grid electrode 6 can be rubbed and cleaned by the cleaning pad 19, so that the surface of the grid electrode 6 can be prevented from being contaminated by ink.

Further, according to this embodiment, since the gap between the grid electrode 6 and the surface of the photosensitive drum 1 can be accurately maintained by the projection 22, the gap between the grid electrode 6 and the surface of the photosensitive drum 1 can be maintained. The electric field strength of is always constant,
Stable development can be performed.

In this embodiment, the electrostatic latent image on the photoconductor is applied, but the present invention is not limited to this.
It can also be applied to a latent image on a dielectric formed by ion flow, a multi-stylus, etc. When a photoconductor is used, it has a resistivity of 10 ⁹ to 10 ¹³ Ωcm on the surface of the photoconductor. Forming a protective film having a thickness of up to 20 μm and forming a latent image under the protective film is advantageous for disturbance of the latent image due to ink.

In this embodiment, the conductive ink is used, but it may be a conductive solid or liquid particles dispersed in an insulating liquid, and the liquid itself is conductive. Good. A polar liquid such as ethyl alcohol can also be used.

As the transfer device, transfer by the transfer roller 10 is preferable as in this embodiment. In this case, the pressure greatly contributes to the transfer, but the conductive particles are dispersed in water as in this embodiment. In the case of ink, since the conductive color material particles retain the electric charge, applying a bias voltage having a polarity opposite to that of the electric charge of the ink to the transfer roller 10 is effective for improving the transfer rate.

Further, since the liquid ink is used in the present embodiment, there is a problem that the liquid ink dries and sticks to the grid electrode 6, the ink guide 7, the ink pump 9 and the like to be contaminated. Therefore, although not shown, a lid for blocking outside air is provided in the opening portion of the developing device 4 facing the surface of the photosensitive drum 1, and the lid is configured to be closed at a timing other than when the developing device 4 is operating. Is desirable.

Further, in this embodiment, the structure using the grid electrode 6 is described, but the liquid ink 17 is used without using the grid electrode 6 at a position other than the position facing the surface of the photosensitive drum 1. It is also possible to provide an electrode for generating the vertical electric field on the liquid surface to inject an electric charge into the ink mist and supply the charged ink mist onto the surface of the photosensitive drum 1 by an air flow.

[0039]

According to the first aspect of the invention, since a substantially uniform mist-like ink is generated over a length corresponding to the image width of the image carrier surface, an image with high density and uniform density can be obtained. can get. Further, since the vibration generator can be arranged close to the surface of the image carrier, the loss of the generation of the atomized ink due to the recombination of the atomized ink is eliminated, and the efficiency of supplying the atomized ink to the surface of the photosensitive drum 1 is reduced. do not do. Further, it is also advantageous for downsizing the copying machine.

Further, according to the invention of claim 2, the liquid surface of the liquid ink can be vibrated to generate the atomized ink without contacting the vibration generator with the liquid ink. Contamination of the vibration generator with the liquid ink can be prevented.

According to the third aspect of the present invention, since the atomized ink can be charged by injecting the electric charge, it is not necessary to use corona discharge as in the conventional case. Therefore, generation of ozone is eliminated, and it is not necessary to handle high voltage.

Further, according to the invention of claim 4, by the grid electrode to which a predetermined voltage is applied, the fog-like ink is charged and a visible image is formed on the surface of the photosensitive drum 1 by the fog-like ink. Be in control.

Further, according to the invention of claim 5, even when the grid electrode is formed by using a thin metal plate, the gap between the grid electrode and the surface of the image carrier is maintained with high accuracy, and at the time of development. The magnitude of the electric field strength in the gap does not change, and stable development can be performed.

Further, according to the invention of claim 6, the component of the ink dried and fixed on the grid electrode surface is removed, and the surface of the grid electrode is regularly cleaned.
Contamination of the grid electrode can be prevented, and more stable development can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electrophotographic copying machine according to an embodiment.

FIG. 2 is a perspective view of a developing device 4 in FIG.

3A is a side view of a first configuration example of an ultrasonic wave generator, FIG. 3B is a side view of a second configuration example of an ultrasonic wave generator, FIG.
(C) is explanatory drawing of the amplitude of the standing wave by the ultrasonic vibrating body 5.

FIG. 4 is an explanatory diagram of the amplitude of a standing wave generated by two ultrasonic vibrators.

FIG. 5 is a side view of a third configuration example of the ultrasonic wave generator.

FIG. 6 is a cross-sectional view of a second configuration example of the developing device.

FIG. 7 is a sectional view of an ink bottle portion in a third configuration example of the developing device.

FIG. 8 is an explanatory diagram of charging and development of ink mist.

FIG. 9 is a perspective view of the periphery of a grid electrode provided with a cleaning pad.

FIG. 10A is a schematic view of the periphery of a grid electrode provided with insulating protrusions, and FIG. 10B is a partial view of the grid electrode provided with insulating protrusions as seen from the photosensitive drum side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 4 Developing device 5 Ultrasonic vibrator 6 Grid electrode 7 Ink guide 12, 15 Ultrasonic vibrator 17 Liquid ink 19 Cleaning pad 22 Insulating protrusion

Claims (6)

[Claims] 1. A mist-like ink generating means for generating a mist-like ink by vibrating a liquid surface of the liquid ink with a vibration generator,
In the image forming apparatus having a charging unit for charging the mist-like ink and developing the electrostatic latent image on the surface of the image carrier using the charged mist-like ink, the vibrating body of the vibration generator is An image forming apparatus having a length corresponding to an image width on an image carrier surface. 2. A mist-like ink generating means for generating a mist-like ink by vibrating the liquid surface of the liquid ink with a vibration generator,
An image forming apparatus having a charging unit for charging the mist-like ink and developing the electrostatic latent image on the surface of the image carrier using the charged mist-like ink, the vibration generator and the liquid ink. An image forming apparatus characterized in that a diaphragm is provided between the two. 3. A mist-like ink generating means for generating a mist-like ink by vibrating the liquid surface of the liquid ink with a vibration generator,
An image forming apparatus, comprising: a charging unit for charging the mist-like ink, for developing an electrostatic latent image on the surface of the image carrier by using the charged mist-like ink. An image forming apparatus comprising: a means for generating an electric field substantially perpendicular to the liquid surface between the liquid surface and the liquid surface of the liquid ink. 4. A grid electrode is provided between the surface of the image carrier and the liquid surface of the liquid ink, the surface potential of the image portion on the surface of the image carrier is V1, the surface potential of the non-image portion is Vd, and the grid electrode. Vg> Vg, Vd>Vg> Vl, or Vv <Vg, Vd <Vg <Vl, where Vg is the voltage applied to the ink and Vv is the voltage applied to the electrode on the liquid ink side. The image forming apparatus according to claim 3, wherein the voltage is applied to the grid electrode. 5. An insulating member is provided between the grid electrode and the image carrier surface so as to maintain a distance between the grid electrode and the image carrier surface.
Image forming device. 6. The image forming apparatus according to claim 4, further comprising a cleaning member for cleaning the surface of the grid electrode.