JPH10278337A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fly a constant quantity of toner by improving fluctuation in the flying quantity of toner due to difference of flying conditions thereof caused by difference in the distance between a toner carrier and a counter electrode. SOLUTION: A counter electrode 17 is subdivided into counter electrodes 17-1...17-4 corresponding to respective gates 29-1...29-4 and connected, respectively, with power supplies 18-1...18-4 supplying different potentials. According to the arrangement, flying conditions of toner are equalized and the flying quantity of tone is made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a printer unit of a digital copying machine or a facsimile machine, a digital printer, a plotter, and the like. In particular, an image forming apparatus for directly forming an image on a recording medium by flying a developer. Related to the device.

[0002]

2. Description of the Related Art As a method of forming a visible image on a recording material such as paper from an electrical signal output from a computer, word processor, facsimile, or the like, an ink jet system using ink, a thermal transfer system for melt-transferring ink, sublimation, In general, image forming methods using a method such as an image forming method and an electrophotographic method are well known.

With the recent increase in speed and image quality, an electrophotographic system has been adopted in which a photosensitive member is irradiated with light to form a toner image on the photosensitive member and is transferred onto a recording medium such as paper. This converts an electric signal into light using a laser or LED head, irradiates the light onto a photoreceptor that has been uniformly charged in advance, and forms an electrostatic latent image on the photoreceptor surface according to the light intensity. Then, the toner stored in the toner carrier is brought into contact with or flying on the electrostatic latent image to form a toner image on the surface of the photoreceptor, and the toner image is electrically attracted to a recording medium. The toner image is fixed on the recording medium by applying both heats or one of them.

Therefore, there has been proposed an image forming apparatus for forming an image on a recording member without requiring a photoreceptor or the like. For example, in Japanese Patent Application Laid-Open No. Hei 6-91918, an electric field is applied to a toner as a developer, the toner is caused to fly by an electric force, and a potential applied to a control electrode including a plurality of through holes arranged in a flight path is changed. An image forming apparatus that forms a toner image on a recording medium by causing the toner image to adhere directly to the recording medium has been proposed.

[0005] The image forming apparatus according to this prior art includes a carrier for carrying a developer, that is, a toner as a developer, a back electrode (opposite electrode) arranged on the recording medium side, and the above described interposed between the two. And a control electrode by a matrix drive having a toner passage hole. Then, the passing potential at which the toner on the carrier passes through the passage hole of the control electrode or the non-passing potential at which the toner cannot pass is selectively switched according to the image data to control the application, so that the toner is directly applied to the surface of the paper as the recording medium. It becomes possible to form a toner image.

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 6-919.
In an apparatus that directly forms an image on recording paper by flying toner, such as the image forming apparatus described in Japanese Patent Application Publication No. 18-182, the configuration of the control electrode greatly affects the image to be formed. That is, by controlling the potential supplied to the control electrode, it is possible to control the passing amount of the toner as the developer.

In particular, by controlling the voltage supplied to the control electrode, the amount of toner as a developer can be controlled. Therefore, the toner carrier is usually formed in a cylindrical shape,
The distances to the gates, which become the passage holes for a plurality of two-dimensionally arranged toners, are different. Therefore, if the potential supplied to the electrode corresponding to the gate is kept constant, the flying condition of the toner is naturally different, and a difference occurs in the recording performance. For this reason, the flying amount of the toner differs depending on the arrangement position of the gates, and the density of the formed image varies, thereby greatly deteriorating the image quality.

In view of this, it is conceivable to control the potential or the supply time supplied to the electrode provided corresponding to the gate constituting the control electrode as described above to correct the toner flying amount and make it constant. In order to change the voltage supplied to the electrodes as described above, a plurality of power supplies are required for each electrode, and each requires a switching unit. In addition, the circuit becomes complicated in order to support a large number of gates, and the cost is greatly increased.

Further, when controlling the supply time of the potential to be supplied to the electrode corresponding to the gate of the control electrode, the supply time is limited to the flight control in the flight direction in which the distance from the toner carrier to the electrode is long. There is a problem that time cannot be reduced.

Another object of the present invention is to provide an image forming apparatus capable of maintaining a stable image quality by making the flying amount of the developer constant by simple means to solve the above-mentioned problem.

In particular, conventionally, in order to fly a developer, a control electrode is provided between a carrier and a counter electrode supplied with a flying potential. This is a single electrode structure that extends two-dimensionally so as to correspond to the arranged gates. Therefore, in the related art, in order to control the amount of flying toner in correspondence with each gate, it is necessary to control the potential supplied to the electrodes provided corresponding to each gate constituting the control electrode.

In this regard, the present invention does not control the voltage supplied to each electrode constituting the control electrode, but controls the potential supplied to the counter electrode side or the supply time to achieve the above-described problems, especially This is to solve the problem.

[0013]

In order to achieve the above-mentioned object, an image forming apparatus according to the present invention comprises a carrier for carrying a developer charged to a predetermined polarity, and a carrier arranged opposite to the carrier. A counter electrode, and a gate for allowing the developer to pass between the carrier and the counter electrode, and forming an electrode for selectively controlling the passage of the developer through the gate accordingly. The control electrode is configured to control the supply of the developer passing potential to the control electrode according to the image data, thereby selectively passing the developer through the gate to record a desired image. In the image forming apparatus, the gate formed on the control electrode is two-dimensionally arranged and the counter electrode is divided and formed corresponding to each of the two-dimensionally arranged gates. The divided counter electrode, which is divided, There wherein the different potentials to be constant or supply time is controlled.

Therefore, even if the carrier carries the developer on a cylindrical surface for transporting the developer, the distance from the counter electrode to the counter electrode via the gate formed on the control electrode can be improved. By controlling the supply potential or the supply time in accordance with, the flying amount of the developer can be controlled to be constant regardless of the difference in distance. For example, when the distance between the support and the counter electrode is long, if the potential or the supply time to be supplied to the divided counter electrode is increased, the shortage of the flying amount can be compensated and the constant flying amount can be obtained. it can. As a result, since the flying amount is stabilized, the image quality can be stabilized.

In the image forming apparatus having the above-mentioned structure, a potential for causing the developer to fly periodically is supplied to the divided opposing electrodes, and a potential for causing the developer to fly is supplied to the divided opposing electrodes. By controlling the supply of a potential lower than the potential at which the developer flies to the divided opposing electrode adjacent to the divided opposing electrode, the flying developer can be narrowed down. In other words, when a potential lower than usual is supplied to the divided opposing electrode adjacent to the divided opposing electrode while the electric potential for flying the developing agent is supplied to the divided opposing electrode, the electric field for causing the developing agent to fly becomes the developer. A narrowed equipotential state is established. For example, as shown in FIG. 6B, the equipotential curve in the region of the gate (29) of the control electrode (19) for flying the developer (13) acts to narrow the developer. Therefore, the flying developer reaches the recording paper 4 without being scattered. As a result, not only the resolution is improved, but also fog and the like are eliminated, and excellent image quality can be compensated.

On the other hand, an image forming apparatus for achieving the above-mentioned object of the present invention comprises a carrier for carrying a developer charged to a predetermined polarity, a counter electrode arranged opposite to the carrier, A control electrode having a gate between the carrier and the counter electrode for allowing the developer to pass therethrough, and forming an electrode for selectively controlling the passage of the developer via the gate accordingly. An image forming apparatus that selectively controls the supply of the developer through the gate to record a desired image by controlling the supply of the developer passing potential to the control electrode according to the image data. The gate formed on the control electrode is two-dimensionally arranged and arranged, and the counter electrode is divided and formed corresponding to each of the two-dimensionally arranged gates. It is provided so as to sandwich it, It made the split counter electrode potential supplied by varying respectively, characterized in that it suitably deflection control the flying direction of the developer.

That is, as shown in FIG. 7, corresponding to the gate (29) of the control electrode (19) arranged between the developer carrier (15) and the counter electrode (17), The gate 29 is positioned so as to be sandwiched between the divided opposing electrodes 17-1 and 17-2, that is, between the divided opposing electrodes 17-1 and 17-2. Thereby, the divided opposing electrode 17-1
If the potential supplied to the electrodes 17-2 and 17-2 is the same, the developer flies straight, and if the potential supplied to the divided opposing electrode 17-1 is increased, the developer is deflected so as to fly in that direction. Is done. Therefore, since it can be arbitrarily deflected in the direction of the developer that flies corresponding to one gate, a high-quality image can be formed.

Further, another image forming apparatus for achieving the object of the present invention comprises: a carrier for carrying a developer charged to a predetermined polarity; a counter electrode disposed opposite to the carrier; A control electrode having a gate between the carrier and the counter electrode for allowing the developer to pass therethrough, and forming an electrode for selectively controlling the passage of the developer via the gate accordingly. An image forming apparatus that selectively controls the supply of the developer through the gate to record a desired image by controlling the supply of the developer passing potential to the control electrode according to the image data. And the gate formed on the control electrode is two-dimensionally arranged, and the counter electrode is divided and formed corresponding to each of the two-dimensionally arranged gates. Keep the distance between the electrode and the carrier constant Characterized in that the placed.

According to this configuration, the distance over which the developer flies can be determined irrespective of the positions of the two-dimensionally arranged gates.
Since it is constant, the flight conditions can be almost matched. Therefore, since the potential supplied to each divided counter electrode can be controlled singly, the circuit configuration is simplified, and the cost can be significantly reduced.

Further, in the image forming apparatus having the above-described configuration, if the divided counter electrodes are arranged so that their surfaces are substantially perpendicular to the toner flying direction, the flying conditions naturally match. Therefore, the effect is promoted.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows details of an image forming unit constituting an image forming apparatus of the present invention, and is a cross-sectional view particularly showing a structure of a counter electrode according to the present invention.
FIG. 2 is a timing chart of the potential supplied to the counter electrode. FIG. 3 is a plan view showing an example of a control electrode according to the present invention. FIG. 4 is a diagram showing a case where a control electrode is provided to control the passage of toner, which is a developer, to form an image directly on a sheet-like recording paper as a recording medium. FIG. 1 is a view schematically showing an example of an image forming apparatus that performs the following.

First, the outline of each element of the printer as the image forming apparatus according to the present invention will be described with reference to FIG. As shown in FIG. 4, the image forming apparatus 1 converts an image corresponding to an image signal (image data) transferred from a host computer or the like, which is an information processing apparatus, into a recording medium using toner as a developer. Is visualized on paper (recording paper). That is, the image forming apparatus of the present invention
An image is formed directly on recording paper by selectively controlling the flight of toner based on image data.

Therefore, the image forming apparatus 1 includes an image forming unit 3 therein, and a paper feeding device is provided on a side of the recording paper entering the image forming unit 3. The paper feeding device includes a paper cassette 5 that stores recording paper 4 as a recording medium, a pickup roller 6 that sends out the recording paper 4 from the paper cassette 5, a paper feed guide (not shown) that guides the supplied recording paper 4, and a pair of paper feed guides. It consists of a registration roller.
The paper feeding device includes a paper feeding sensor (not shown) that detects that the recording paper 4 has been supplied. The pickup roller (paper feed roller) 6 is driven by a driving device (not shown).

Further, the toner image formed on the recording paper 4 by the image forming unit 3 is fixed to the recording paper 4 by heating and pressing the toner image on the recording paper 4 output side from the image forming unit 3. A fixing unit 7 is provided. The fixing unit 7 includes a heater 8,
It comprises a heating roller 9, a pressure roller 10, a temperature sensor 11, and a temperature control circuit 12. The heating roller 9 is made of, for example, an aluminum tube having a thickness of 2 mm. The heater 8 is formed of, for example, a halogen lamp, and is built in the heating roller 9. The pressure roller 10 is made of, for example, a silicone resin. The heating roller 9 and the pressure roller 10 provided opposite to each other are loaded with a load of 2 kg, for example, by springs (not shown) at both ends of each shaft so that the recording paper 4 can be pressed therebetween. Have been added.

The temperature sensor 11 measures the temperature of the surface of the heating roller 9. The temperature control circuit 12 is controlled by a main control unit described later, controls ON / OFF of the heater 8 based on the measurement result of the temperature sensor 11, and maintains the surface temperature of the heating roller 9 at, for example, 150 ° C. . Further, the fixing unit 7 includes a paper discharge sensor (not shown) that detects that the recording paper 4 has been discharged. The materials of the heater 8, the heating roller 9, the pressure roller 10, and the like are not particularly limited. Further, the temperature of the surface of the heating roller 9 is not particularly limited. Further, the fixing unit may be configured to fix the toner image by heating or pressing the recording paper 4.

Although not shown, on the paper output side of the recording paper 4 from the fixing unit 7, a discharge roller for discharging the recording paper 4 processed by the fixing unit 7 onto a discharge tray, and a discharged recording paper A discharge tray for receiving the paper 4 is provided. The heating roller 9, the pressure roller 10, and the paper discharge roller are driven by a driving device (not shown).

The toner supply unit 31 constituting the image forming unit 3
Are provided inside a toner storage tank 14 in which a toner 13 as a developer is stored, a toner support 15 as a cylindrical support (sleeve) for holding the toner 13 by magnetic force, and the toner storage tank 14. It comprises a doctor blade 16 which charges the toner 13 and regulates the thickness of the toner layer carried on the outer periphery of the toner carrier 15. The doctor blade 16 is provided on the upstream side in the rotation direction of the toner carrier 15 so that the distance from the outer peripheral portion of the toner carrier 15 is, for example, 60 μm.

The toner 13 is, for example, a magnetic toner having an average particle diameter of 6 μm, and is charged by the doctor blade 16 so that the charge amount is, for example, −4 μC / g to −5 μC / g. The distance between the doctor blade 16 and the toner carrier 15 is not particularly limited.
In addition, the average particle size, charge amount, and the like of the toner 13 are not particularly limited.

The toner carrier 15 is driven by a driving device (not shown) and rotates in the direction of arrow A in the figure, for example, at a surface speed of 80 mm / sec. The toner carrier 15 is grounded, and magnets (not shown) are arranged inside the toner carrier 15 at positions facing the doctor blade 16 and control electrodes to be described later. Thereby, the toner carrier 15 can carry the toner 13 on the outer peripheral surface. The toner 13 carried on the outer peripheral surface of the toner carrier 15 forms ears at positions corresponding to the positions on the outer peripheral surface. The rotation speed of the toner carrier 15 is not particularly limited. Further, the toner carrier 15
Instead of carrying the toner 13 by a magnetic force, the toner 13 may be carried by an electric force or an electric force and a magnetic force.

The printing section 32 constituting the image forming section 3 is made of, for example, an aluminum plate having a thickness of 1 mm, and has a counter electrode (back electrode) 17 facing the outer peripheral surface of the toner carrier 15.
A counter electrode voltage power supply 18 for supplying a high voltage to the counter electrode 17; a control electrode 19 provided between the counter electrode 17 and the toner carrier 16;
And a neutralizing voltage power supply 2 for applying a neutralizing potential to the neutralizing member 20.
1. A charging member 22 composed of a brush or a roller for charging the recording paper 4, a charging voltage power supply 23 for applying a charging potential to the charging member 22, a dielectric belt 24, and a supporting roller for supporting the dielectric belt 24 25 and 26 are provided.

Although the counter electrode 17 is shown as a single electrode structure in FIG. 4, the present invention has a plurality of divided electrode structures as shown in FIG. Here, a single electrode will be described in order to explain the toner flight, but the counter electrode 17 is provided so that the distance from the outer peripheral surface of the toner carrier 15 is, for example, about 1.1 mm. The dielectric belt 24 is made of PVDF (polyvinylidene fluoride) as a base material and has a volume resistivity of 10 ¹⁰ Ω · c.
This is an endless belt made of a material of about m and having a thickness of about 75 μm. The dielectric belt 24 is driven by a driving device (not shown), and rotates in a direction indicated by an arrow in the drawing, for example, at a speed of 30 mm / sec on its surface.

A high voltage of, for example, 2.3 kV is applied to the common electrode 17 by a common electrode voltage power supply 18. That is, an electric field necessary for causing the toner 13 carried on the toner carrier 15 to fly in the direction of the counter electrode 17 is applied between the counter electrode 17 and the toner carrier 15 by the high-voltage power supply 18.

The static elimination member 20 includes a dielectric belt 24.
Is provided on the downstream side of the control electrode 19 in the rotational direction so as to be in pressure contact with the dielectric belt 24. A neutralization potential of 2.5 kV is applied to the neutralization member 20 by a neutralization voltage power supply 21 to eliminate unnecessary charges existing on the surface of the dielectric belt 24. The material of the counter electrode 17 is not particularly limited. Further, the distance between the counter electrode 17 and the toner carrier 15 is not particularly limited. Further, the voltage applied to the counter electrode 17 is not particularly limited.

The dielectric belt 2 on the drive roller 26 side
4 is provided with a blade, and the blade is a cleaning member for removing toner directly attached to the surface of the dielectric belt 24 due to, for example, jamming of the paper 4. As a result, in image formation after the paper jam is removed, the back surface of the paper is
4 is prevented from being stained by the toner attached thereto. A toner collection container (not shown) for receiving the removed toner is provided corresponding to the cleaning blade.

Further, although not shown, the image forming apparatus according to the present invention not only receives image data from outside as described above, but also receives image data from a scanner or the like for reading an image of a document or the like. be able to. That is,
The image forming apparatus main body is provided with a scanner, and furthermore, an image processing section that performs image processing on the image data into data that can be recorded and reproduced by the image forming section, a control section that controls the entire image forming apparatus, and an image processing section. A storage unit for storing data as required, a conversion unit for converting image data into data to be supplied to the control electrode 19 of the image forming unit according to the present invention, and the like are provided.

On the other hand, the control electrode 19 is parallel to the tangential direction of the surface of the counter electrode 17, and
It has a structure in which the toner flow from the toner carrier 15 to the counter electrode 17 can pass through in a three-dimensional manner. The electric field applied between the toner carrier 15 and the counter electrode 17 changes according to the potential supplied to the control electrode 19, and the toner 1 from the toner carrier 15 to the counter electrode 17 changes.
7 is controlled. Further, the control electrode 19 is provided so that the distance from the outer peripheral surface of the toner carrier 15 is, for example, 100 μm, and is fixed by a support member (not shown).

FIG. 3 shows an example of the control electrode 19 according to the present invention. According to the control electrode 19, the insulating substrate 27, the high-voltage driver (not shown), and the independent ring-shaped ring-shaped electrodes are used. 28. In particular, the ring-shaped electrode 28 has a through hole 2 through which the toner passes.
9 is formed, and a passage hole 29 is formed in the opening. In addition, on the surface of the substrate 27 facing the toner carrier 15 side, there is provided one shield electrode 30 for controlling passage or non-passage of the toner.

FIG. 3 is a plan view particularly viewed from the counter electrode 17 side. The insulating substrate 27 is made of, for example, a polyimide resin and has a thickness of 25 μm.

The ring-shaped electrode 28 has, for example, a thickness of 1
The through hole, that is, the gate 29 is provided in the opening of the electrode 28 and is formed according to a predetermined arrangement. Each passage hole 29 is a passage portion for the toner 13 flying from the toner carrier 15 to the counter electrode 17. Hereinafter, this passing portion is referred to as a gate 29.

On the other hand, the shield electrode 30 is made of, for example, copper foil, and has openings formed so as to correspond to the gate 29 and the ring electrode 28 provided around the gate 29. In particular, the diameter (diameter) of the opening of the ring-shaped electrode 28
Is formed, for example, to about 200 μm, and the diameter of the opening of the shield electrode 30 is formed, for example, to about 240 μm. The above-mentioned gate 29 is formed in an opening corresponding to each of the electrode 28 and the shield electrode 30, and the opening diameter of the gate 29 is formed to be, for example, about 160 μm.

The distance between the control electrode 19 and the toner carrier 15 is not particularly limited. Gate 29
The size and the material and thickness of the insulating substrate 27, the ring-shaped electrode 28 and the shield electrode 30 are not particularly limited. The shield electrode 30 is for supplying a potential that does not cause toner to fly during non-recording, and may not be provided.

The number of the gates 29 formed on the substrate 27 is not limited to 300.
When dots are formed by pi (dot per inch), for example, 2560 dots are formed.
The shield electrode 30 is connected to the above-described control electrode voltage power supply 3 via each power supply line and a high voltage driver (switching).
3 is electrically connected.

The ring electrode 28 and the shield electrode 3
The surface 0 will be described in detail later.
It is covered with a certain degree of insulator layer (protective layer 34), and the insulation between the electrodes is ensured so that the electrodes are protected from being connected to each other. The material and thickness of the insulator layer 34 are not particularly limited.

The above-mentioned ring-shaped electrode 28 of the control electrode 19
The control electrode voltage power supply 33 applies a pulse corresponding to an image signal, that is, a voltage to the shield electrode 30. That is, the control electrode voltage power supply 33 applies, for example, 150 V (hereinafter referred to as an ON potential) to the ring electrode 28 and the shield electrode 30 when the toner 13 carried on the toner carrier 15 passes in the direction of the counter electrode 17. However, when the light is not passed, for example, -200 V (hereinafter referred to as OFF potential) is applied. The values of the ON potential for causing the toner to fly and the OFF potential that does not cause the toner to fly are not particularly limited, and may be set as appropriate.

Here, the image forming process of the present image forming apparatus will be described. First, the main control unit of the image forming apparatus 1 that has received image data from the host computer or the scanner serving as the image reading apparatus starts an image forming operation.

Upon receiving the image data, the image forming apparatus 1 starts an image forming operation. In this case, the recording paper 4 in the paper cassette 5 is sent out toward the image forming unit 3 by the pickup roller 6 shown in FIG. It is detected by. The recording paper 4 sent out by the pickup roller 6 is transported between the charging member 22 and the support roller 25. The same potential as that of the counter electrode 17 is applied to the support roller 25 by the power supply 180. Charging member 22
1.2 k as the charging potential by the charging voltage power supply 23
V is applied. The recording paper 4 is supplied with a charge due to a potential difference between the charging member 22 and the support roller 25, and is electrostatically adsorbed on the surface of the printing unit 32 of the image forming unit 3 facing the toner belt 15 of the dielectric belt 24 in the printing unit 32. Conveyed.

Thereafter, a potential is supplied from the control electrode voltage power supply 33 to the control electrode 19 in accordance with the image data. The supply of the potential is performed at a timing synchronized with the supply of the recording paper 4 to the printing unit 32 by the charging member 22. The control electrode voltage power supply 33 applies an ON potential or an OFF potential to the predetermined control electrode 19, that is, the ring-shaped electrode 28, as appropriate, according to a signal of image data.
The ON potential is supplied at the start timing of the image forming operation. Therefore, the electric field near the control electrode 19 is controlled. That is, at the gate 29 of the control electrode 19, the prevention of the flying of the toner 13 from the toner carrier 15 to the counter electrode 17 and the release thereof are appropriately performed according to the image data.

Thus, a toner image corresponding to the image signal is formed on the recording paper 4 moving at a speed of 30 mm / sec toward the paper output side by the rotation of the support rollers 25 and 26. The recording paper 4 on which the toner image has been formed is peeled off from the dielectric belt 24 at the curvature of the support roller 26 and is conveyed to the fixing unit 7 where the toner image is fixed on the paper 4. The recording paper 4 on which the toner image has been fixed is discharged onto a paper tray by a paper discharge roller, and normal discharge is detected by a paper discharge sensor. Based on this detection operation, the main control unit of the printer 2 determines a normal end of the printing operation.

By the above image forming operation, a good image is formed on the recording paper 4. The image forming apparatus includes a recording paper 4
Since an image is formed directly on the upper surface, a visualizer such as a photoconductor or a dielectric drum used in a conventional image forming apparatus is not required. Therefore, the transfer operation for transferring the image from the visualized object to the recording paper 4 is omitted, so that the image does not deteriorate.
For this reason, the reliability of the device is improved, the configuration of the device is simplified, and the number of components is reduced, so that downsizing and cost reduction can be achieved.

(Description of an Embodiment of the Present Invention) Here, the counter electrode 17 constituting the image forming section according to the present invention is not a single electrode but is divided into a plurality of electrodes. The opposing electrode 17 is formed on each of the divided general electrodes 17-1 to 17-4 by, for example, etching a conductive foil provided on an insulating substrate 17a, thereby protecting the surface and short-circuiting between the electrodes. The surface is covered with an insulating material 17b to prevent the like. The surface of the insulating material 17b facing the control electrode 19 is flat.

Each of the divided counter electrodes 17-
Numerals 1 to 17-4 are formed in a band shape, and are provided particularly corresponding to the horizontal lines of the gate 29 of the control electrode 19 shown in FIG. That is, the control electrode 19 shown in FIG.
Has two-dimensionally arranged gates 29. In particular, four gates 29-1 to 29-4 are grouped, and these are arranged with a slight shift in the direction perpendicular to the line and in the line direction. . The four gates are formed so as to have the same position, that is, the line direction (29-1).

The divided opposing electrodes 17-1 to 17-4 of the opposing electrode 17 are provided corresponding to the gates 29 of the control electrodes 19 arranged as described above. Here, each divided counter electrode 17-1 to 17-4 of the counter electrode 17
Has a width of, for example, about 150 μm,
The pitch between the divided opposing electrodes is set to, for example, about 150 μm. The insulating material 17b that insulates the surfaces of the divided opposing electrodes 17-1 to 17-4 has a thickness of about 100 μm. These numerical values are not particularly limited, but may be appropriately set in consideration of the resolution and the like.

In FIG. 1, since the toner carrier 15 is formed in the shape of a cylindrical roller, the control electrode 19 and the counter electrode 17 are provided in a two-dimensional horizontal state. The distance to the electrode 17 differs individually. Therefore, the conditions under which the toner passes through the gate 29 in response to the flying potential supplied from the toner carrier 15 to the control electrode 19 are different. As a result, the amount of passing toner differs, which greatly affects the image quality.

Therefore, as shown in FIG.
In order to make the amount of the toner flying from 5 pass through each gate of the control electrode 19, in the present invention, as described above, the counter electrode 17 is connected to each gate 29-1 to 29- of the corresponding line. 4 corresponding to the divided counter electrode 17
-1 to 17-4 structure. Therefore, each of the divided opposing electrodes 17-1 to 17-4 is connected to each of the power supplies 18-1 to 18-4 so that the supplied electric potential is different from each other.

The power supplies 18-1 to 18-4 supply different potentials to the divided opposing electrodes 17-1 to 17-4 of the opposing electrodes.
1 and 17-4 at power supplies 18-1 and 18-4.
A potential of 8 kV is supplied to the divided electrodes 17-2 and 17-3 by the power supplies 18-2 and 18-3. Each power supply is controlled by a power supply control circuit 18C to control the supply of a potential to each of the divided counter electrodes 17-1 to 17-4 of the counter electrode 17 by the power supplies 18-1 to 18-4. Supply control is performed.

Thus, with respect to the toner carrier 15,
The potential of each divided counter electrode 17-1, which passes through each gate 29 of the control electrode 19 and is different from the potential supplied to the divided counter electrodes 17-1 to 17-4 according to the distance to the counter electrode 17, is reduced. The potential supplied to −2 and 17-3 is lower than the potential supplied to the divided opposing potentials 17-1 and 17-4 on both sides. As a result, in a portion where the distance over which the toner flies, the corresponding electric field intensity can be ensured, so that it is possible to compensate for a decrease in the amount of the flying toner. Therefore, it is possible to cause the toner to fly under the same conditions as the electric field strength at a short distance and to the counter electrode side. Therefore, it is possible to fly a predetermined amount of toner irrespective of the difference in distance, and to stabilize the image quality to be formed.

Here, in the power supply control circuit 18C, the supply of the power supply voltage to each divided counter electrode is controlled. Therefore, the scanning may be sequentially switched for each gate corresponding to each line without simultaneously supplying a predetermined potential to all the divided opposing electrodes.

For example, as shown in FIG.
At 8C, the output is sequentially controlled from each of the power supplies 18-1 to 18-4 and supplied to the divided opposing electrodes 17-1 to 17-4. With this control, the passing potential is supplied to the control electrode 19 at a timing when the potential is supplied to the divided electrodes at the timing when the toner passes through the gate.
No fogging or the like is formed without wasteful toner flying.

In FIG. 2, each divided counter electrode 1
The width of the potential supplied to 7-1 to 17-4, that is, the supply time is controlled. This is the power control circuit 1 described above.
8C, the supply time width is controlled. In particular, the supply times t1 and t4 to the divided opposing electrodes 17-1 and 17-4 on both sides are longer, and the supply time t2 to the divided opposing electrodes 17-2 and 17-3 is increased. , T3 are shortened. For example, the time of t1 and t4 is set to 768 μsec, and the time of t2 and t3 is set to 512 μsec.
Set to about sec.

In this case, even if the output voltage value of each of the power supplies 18-1 to 18-4 is fixed, the divided electrodes 17-
Since the potential for flying toner for a long time is supplied to 1, 17-4, even if the condition for flying toner is different from the condition of divided electrodes 17-2 and 17-3 in the center, This makes it possible to perform toner flight control. That is, it is possible to cause the same toner flying as the central portion.

In such a configuration, only one power supply is provided without providing a plurality of power supplies, and the divided counter electrode 17 is provided with a waveform as shown in FIG.
Switching supply to -1 to 17-4 can be controlled. In this case, a switching means is interposed between the power supply circuit and the divided counter electrode, and the switching means is controlled by the power supply control circuit 18C.

The supply times t1 to t4 of the potentials from the respective power supplies 18-1 to 18-4 are not limited to the above-described example, and may be set appropriately to a time that can compensate for the toner flight. Further, it goes without saying that the above-mentioned supply potential may be adjusted simultaneously with the supply time control.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. In FIG. 5, the image forming section is configured with a control electrode 19 interposed between a toner carrier 15 and a counter electrode 17. The control electrode 19 has one gate for passing the toner. This is for simplifying the description of the second embodiment. For example, as shown in FIG. 1, four gates 29 are arranged along the transport direction of the recording paper 4.

Each of the divided opposing electrodes 17-
Power supplies 18-1 and 18-2 are connected to 1 to 17-3, respectively. In this case, the central divided counter electrode 17-2
The power supply 18-1 is connected to the divided counter electrodes 17-1 and 17-3 adjacent to both sides of the central electrode. Then, by supplying a potential from the power supply 18-1 to the central divided opposing electrode 17-2, the toner flies from the toner carrier 15 side via the gate 29 of the control electrode 19.

By supplying a potential for causing toner to fly to the central divided counter electrode 17-2 via the power supply 18-1, the first timing at which the toner is carried out from the toner carrier 15 is performed. In the embodiment, the divided opposing electrodes 17-1 and 17-1 adjacent to the divided electrode 17-2 are used.
Power supply control circuit 18C so that no potential is supplied to 7-3.
Is controlled by. In this embodiment, a potential for causing toner to fly at the same time is supplied to the adjacent divided opposing electrodes 17-1 and 17-3.

In this case, the divided electrodes 17-1 and 17-3
Is supplied with a potential lower than the potential supplied to the central divided electrode 17-2. Therefore, the power supply 18
-1 is set to be higher than the output potential of the power supply 18-2. For example, a split electrode (17-2) for flying toner
2.3 kV, the divided electrode (17-1, 1
A potential of 1.6 kV is supplied to 7-3). This value is merely an example, and is appropriately set.

As described above, when a potential for flying is supplied to the divided electrode in order to fly the toner, a potential lower than that potential is also supplied to the divided counter electrode adjacent thereto. It is possible to reduce the electric field when the toner passes through the gate, and the flying toner reaches the divided counter electrode 17-2 so that the toner is focused.
Therefore, sharpness can obtain image quality. That is, the resolution is improved, and the image quality can be improved.

The function of reducing the electric field will be described in detail with reference to FIG. FIG. 6A shows a flying state of the toner by an equipotential waveform generated by an electric field acting between the toner carrier 15 and the counter electrode 17 in a conventional toner flying state. That is, since the counter electrode 17 has a single electrode structure, the electric field formed between the counter electrode 17 and the toner carrier 15 is not greatly reduced when the toner 13 passes through the gate 29, and is directed toward the recording paper 4. To fly. for that reason,
After passing through the entire area of the gate 29, the recording paper 4
Unnecessary toner also flies around the area corresponding to. For this reason, fog is formed by unnecessary toner, and the image becomes very blurred and the image quality is not clear.

In this regard, according to the embodiment of the present invention, FIG.
As shown in (b), the counter electrode 17 is divided, and the divided counter electrode 17-
The potential supplied to 1, 17-3 is controlled, that is, set to be small and supplied. Therefore, the electric field formed by the toner supply potential and the toner passing potential supplied to the control electrode 19 when the toner 13 flies is narrowed at the gate 29 portion. Therefore, the flying toner 13 is supplied to the gate 29.
When the recording paper 4 passes through the recording paper 4, it is narrowed down. As a result, it is possible to prevent unnecessary toner from reaching the periphery of the focused toner 13 that has reached the recording paper.

Therefore, when forming an image, the dot size can be formed to a predetermined size, and an image with sharp image quality and good resolution can be obtained. Further, since the unnecessary toner does not fly to the periphery, it is possible to obtain an image of stable image quality without fog or the like.

Therefore, in order to perform such a toner flight, when a potential is supplied to the divided opposing electrode for causing the toner to fly in FIG. 1, a potential smaller than the potential for causing the toner to fly is supplied to the divided opposing electrode adjacent thereto. What should I do? For example, in FIG.
At the timing of causing toner to fly through the gate 29-3 corresponding to the divided counter electrode 17-
2, 17-4. This potential is naturally set lower than the flying potential. In this case, the divided electrode 17-4 at the end supplies a large potential when the toner is caused to fly by the electrode. However, when the adjacent divided counter electrode acts as an auxiliary electrode, the electric field is not increased. Is set to a potential that can be reduced as shown in FIG. In this case, since the potential for flying the toner is supplied to the adjacent divided opposing electrodes 17-2 and 17-4, the ring-shaped electrode 28 of the gates 29-2 and 29-4 corresponding thereto is supplied.
Is supplied with a non-passing potential that does not cause toner to fly.

Also, the divided opposing electrodes 17-1 and 17-1 at the ends are provided.
-4, when a potential for flying toner is supplied, one of the adjacent counter electrodes 17-
Although there is 2,17-3, there is no split counter electrode on the opposite side. Therefore, in order to perform good toner flying, as described above, the divided opposing electrode 1 is provided only for the auxiliary electrode without being provided for the purpose of toner flying.
An auxiliary electrode may be provided adjacent to 7-1 and 17-4.

With such a configuration, as shown in FIG. 5, both sides adjacent to the divided opposing electrode for flying toner are promoted to reduce the electric field when passing through the gate 29 using the divided opposing electrode as an auxiliary electrode. Thus, the image quality can be improved.

FIG. 7 shows another example of the second embodiment. This is an example of a case where deflection of flying toner is controlled by using a divided counter electrode divided for flying toner. In particular, in the example shown in FIG. 1, each divided counter electrode 17-1 to 17-4 is arranged corresponding to each gate 29. On the other hand, in the case of FIG.
The gate 29 of the control electrode 19 is arranged so as to correspond between the divided opposing electrodes 17-1 and 17-2, which are the opposing electrodes 17. That is, the divided opposing electrodes 17-1 and 17-2 are provided so as to sandwich the gate 29. This makes it possible to control the formation of dots at at least three different positions on the recording paper 4 for one gate 29. This means that the resolution can be substantially tripled.

Therefore, in FIG.
-1 and 17-2 are connected to power supplies 18-1 and 18-2, respectively.
Is connected. Then, through the power supply, the power supply control circuit 18C controls the divided counter electrodes 17-1 and 17-.
2 is supplied with a predetermined potential.

Now, both divided counter electrodes 17-1 and 17-2
Is supplied to the counter electrode side via the gate 29 of the control electrode 19, the toner flies from the toner carrier 15. At this time, an electric field equivalent to the gate 29 is applied to both divided opposing electrodes 17-1 and 17-2.
That is, if the same potential is supplied, the toner tends to fly between the divided opposing electrodes 17-1 and 17-2. That is, it flies straight down from the toner carrier 15 as shown in the figure.

If the electric potential supplied to the divided opposing electrode 17-1 is made higher than the electric potential supplied to the divided opposing electrode 17-2, the electric field strength on the divided opposing electrode 17-1 side increases, and the flying The toner can be biased toward the divided opposing electric field 17-1. That is, deflection control of the flying direction of the toner can be performed. Conversely, if the potential on the divided counter electrode 17-2 side is made higher, the flying direction of the toner can be deflected toward the divided counter electrode 17-2 side.

When the same potential, for example, 2.3 kV, is supplied to both of the divided counter electrodes 17-1 and 17-2, the flying toner passing through the gate 29 reaches the recording paper straight. Then, 2.8 kV is applied to the divided opposing electrode 17-1.
When 2.3 kV is supplied to the divided counter electrode 17-2, FIG.
At this time, the flying toner is deflected toward the divided counter electrode 17-1 and reaches the recording paper. Conversely, the split counter electrode 17
-1 to 2.3 kV, split counter electrode 17-2 to 2.8 kV
Is supplied, the flying toner is deflected to the divided counter electrode 17-2 and reaches the recording paper. Therefore, three dots can be formed at different positions on the recording paper for one gate 29. Therefore, the pitch between dots can be easily adjusted, and an image with higher resolution can be obtained.

In FIG. 7, the divided opposing electrodes are arranged in one direction, but by arranging the divided opposing electrodes also in a direction orthogonal to the direction, deflection control of the two-dimensional flying toner is performed. You can also.

In this case, too, as described in the first embodiment, when the distance from the toner carrier 14 to the opposing electrode 17 is different as described in the first embodiment, the divided opposing electrodes for supplying a potential for flying are used. By controlling the supply of the potential to the electrodes as described above, a certain amount of toner can be ensured.

(Description of Another Embodiment of the Present Invention) In the above embodiment, the opposing electrode is divided into a plurality of divided opposing electrode structures, and the flight conditions based on the difference in the distance from the toner carrier 15 to the opposing electrode 17 The potential or supply time to be supplied to the divided opposing electrodes is controlled in order to eliminate the difference in the amount of flying toner due to the difference in.

By using divided opposing electrodes without performing supply control by such a power supply, even under the same supply potential, toner flying conditions can be made substantially the same, and a predetermined amount of toner flying can be secured. This embodiment will be described below.

FIG. 8 shows divided opposing electrodes 17-1 to 17-
In the case where 4 is provided on the insulating substrate 17a, the divided opposing electrodes 17-1 to 17-4 are arranged according to the distance from the toner carrier 15. That is, the divided opposing electrodes 17 directly below the toner carrier 15 are so arranged that the distances from the toner carrier 15 to the divided opposing electrodes 17-1 to 17-4 are substantially the same.
With respect to -2 and 17-3, divided opposing electrodes 17-1 and 17-4 at both ends adjacent thereto are provided so as to approach the toner carrier 15.

For this reason, the divided counter electrodes 17-2 and 17-3 are provided on the insulating substrate 17a, and the divided counter electrodes 17-1 and 17-4 are provided on another insulating substrate or the like from above to overlap and overlap with each other. 17 is constituted. In particular, the split counter electrode 17-
When 1 and 17-4 are provided, the thickness of the insulating layer and the thickness of the insulating layer are set so that the distance to the toner carrier 15 is the same as the distance from the divided opposing electrodes 17-2 and 17-3 to the toner carrier 15. The thickness of the insulating substrate on which the divided opposing electrodes 17-2 and 17-3 are provided is appropriately set. In particular, the counter electrodes 17-1, 17
-4 The surface of the insulating material 17c is flat so that the surface is flat.
Is coated.

In such a configuration, the distance between the toner carrier 15 and each of the divided opposing electrodes 17-1 to 17-4 can be made substantially constant. The electric field strength becomes the same. Thus, the flying amount of the toner can be maintained at the determined amount.
In particular, even if the potentials supplied to the divided opposing electrodes 17-1 to 17-4 are the same, the toner flying amount can be kept constant at a predetermined amount.

FIG. 9 shows a further improved relationship between the toner carrier 15 and the divided opposing electrodes 17-1 to 17-4 in FIG. That is, the counter electrode 17 is provided along the curved portion of the toner carrier 15.
In particular, the divided counter electrode 17-facing the toner carrier 15-
2 and 17-3 are provided so as to be perpendicular to the toner flying direction, and the divided opposing electrodes 17-1 and 17-1 on both sides thereof are provided.
7-4 is also arranged so as to be perpendicular to the toner flight direction.

For this reason, since it is necessary to bend the insulating substrate 17a, the insulating substrate 17a is formed of a flexible member, and is bent at an appropriate position, particularly at a portion where no divided counter electrode exists.
As a result, the toner carrier and each divided counter electrode 17-1 to 17-1
The distance to 17-4 can be made constant. In addition, since the surfaces of the divided opposing electrodes 17-1 to 17-4 are arranged at substantially right angles with respect to the flying toner, the toner can accurately fly to the normal position, and the toner scatters. Can be blocked.

In particular, if the recording paper 4 is conveyed along the surface of the insulating layer 17b of the counter electrode 17, the recording paper 4
Then, pixels are formed by the toner, and a desired image can be formed normally.

As described above, in FIGS. 8 and 9, by keeping the distance between the divided counter electrodes 17-1 to 17-4 and the toner carrier 15 constant, the divided counter electrodes 17-1 to 17-4 are fixed.
Since the potential supplied to 1 to 17-4 can be made single, the power supply circuit can be simplified.

(Other Embodiment of Counter Electrode of the Present Invention) In the present invention, the counter electrode 17 has a divided structure. Therefore, it is required to adjust the positional relationship between the control electrode 19 and each of the gates 29-1 to 29-4. Therefore, as shown in FIG.
-4 are integrated into a unit, and this is converted to X as shown in the figure.
It is preferable to make it possible to adjust the direction, the Y direction, and the Z direction.

The X direction is the front-back direction in the drawing of FIG. 1, the Y direction is the left-right direction, and the Z direction is the up-down direction. As shown in FIG. 11, the counter electrode 17 is held by a holder 50 so as to be movable up, down, left, right, and back and forth.
In order to adjust the movement in the X, Y, and Z directions, the holder 50
The movement is adjusted by adjusting screws 51y and 51z provided in the first position.

The adjustment screw 51y is for moving in the horizontal direction in the figure, and is an adjustment screw for the Y direction. The adjustment screw 51z moves in the front-rear direction in the figure, and is particularly an adjustment screw in the Z direction.
Although the X-direction adjustment screw is not shown in FIG. 11, an X-direction adjustment screw having the same configuration is provided at the front and rear portions of the drawing.

In particular, a spring is interposed in each of the adjusting screws so that the opposing electrode 17 can be arbitrarily moved and adjusted in one direction.

With such a configuration, each gate of the control electrode 19 and each divided counter electrode 17-1 forming the counter electrode are formed.
17-4 can be adjusted to the best state.

In the description of the above-described embodiment, gates 29 are two-dimensionally arranged as control electrodes 19, and individual ring-shaped electrodes 28 are provided corresponding to the respective gates 29. In addition to the control electrodes 19, as shown in FIG. 12, strip-shaped row-direction electrodes 28x and line-direction electrodes 28y are formed on the front and back surfaces of the substrate 27 so as to be orthogonal to each other. 2
The control electrode 19 may have a matrix structure in which the electrodes 9 are formed.

For example, the supply control of the NO or OFF potential corresponding to the image signal is performed to the row direction electrode 28x, and the drive control is performed such that the ON potential is periodically supplied to one electrode to the line direction electrode 28y. As a result, the toner flies from the toner carrier 15 through the corresponding gate 29 to which the ON potential is supplied to the electrodes 28x and 28y, and reaches the recording paper 4 to form an image. Therefore, the divided opposing electrodes 17-1 to 17-4 as shown in FIG. 1 may be driven and controlled at the timing of controlling the supply of the ON potential to the line electrode 28 y in FIG.

Further, in the embodiment of the present invention, the colored toner is described as an example of the developer, but the present invention is not limited to the toner, and ink and the like may be used. Even in such a case, each of the above-described embodiments of the present invention can be applied as it is. Further, the configuration of the toner supply unit 31 may be a configuration to which the ion flow method is applied. That is, the image forming unit 3 may be configured to include an ion source such as a corona charger. Also in this case, the same control electrode 19 and counter electrode 17 are provided, and it is possible to control the passage of ions.

In addition, as an image forming apparatus, it can be used for a printing unit of a digital copying machine and a facsimile machine, a digital printer, a plotter, and the like.

[0099]

According to the image forming apparatus of the present invention described above, the opposing electrodes for causing the developer to fly are respectively arranged with respect to the two-dimensionally arranged passing gates of the developer. Since it is divided, the potential and time to be supplied to each divided counter electrode can be easily controlled so that the toner flying amount is constant. Therefore, not only the circuit configuration becomes very simple, but also the cost and the like can be reduced.

Further, by controlling the potential supplied to the divided opposing electrodes, it is possible to easily narrow down the developer and control the deflection in the flight direction, and easily obtain a high-quality and high-resolution image.

Furthermore, even when the supply potential is maintained at a single level, the flying distance of the developer can be kept constant. In other words, the distance between the carrier that carries the developer and the divided opposing electrodes can be set for each gate, so that there is no difference in flight conditions, and a constant amount of flight can be maintained under substantially the same conditions.

Therefore, a circuit configuration for controlling or switching the potential is not required, and a stable image quality can be obtained with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of a divided structure of a counter electrode forming an image forming unit in an image forming apparatus of the present invention.

FIG. 2 is a timing chart for controlling supply of a potential to a divided counter electrode shown in FIG. 1 at a predetermined cycle.

FIG. 3 is a plan view illustrating an example of a control electrode included in the image forming unit illustrated in FIG.

FIG. 4 is a cross-sectional view illustrating an overall configuration example of an image forming apparatus including the image forming unit illustrated in FIG.

FIG. 5 is a cross-sectional view for explaining a second embodiment of a divided structure of a counter electrode forming an image forming unit according to the present invention.

6A and 6B are diagrams illustrating a flying state of a toner with respect to a potential supplied to a divided counter electrode according to FIG. 5, wherein FIG. 6A illustrates a conventional flying state of a toner, and FIG. is there.

FIG. 7 is a cross-sectional view for explaining another embodiment according to the second embodiment of the present invention, which is a divided structure of the opposing electrodes constituting the image forming unit.

FIG. 8 is a cross-sectional view showing another embodiment of the divided structure of the counter electrode constituting the image forming unit according to the present invention.

FIG. 9 is a cross-sectional view showing another example of another embodiment according to the divided structure of the counter electrode constituting the image forming unit according to the present invention.

FIG. 10 is a diagram for explaining the position adjustment of the divided opposing electrodes in the present invention.

11 is a diagram showing an example of an adjustment structure for realizing the position adjustment of the divided opposing electrodes in FIG.

FIG. 12 is a plan view illustrating an example of an electrode structure based on a matrix of control electrodes constituting an image forming unit according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Image forming part 4 Recording paper 13 Toner (developing agent) 14 Toner accommodating part 15 Toner carrier 17 Counter electrode 17-4 to 17-4 Divided counter electrode 17a Insulating substrate 17b Insulating material 18 Power supply control circuit 18C Power control circuit 18-1 to 18-4 Power supply 19 Control electrode 24 Dielectric belt 27 Insulating substrate 28 Ring electrode (electrode) 29 Gate (through hole)

Claims (6)

[Claims] 1. A carrier for supporting a developer charged to a predetermined polarity, a counter electrode disposed opposite to the carrier, and a developer passing between the carrier and the counter electrode. And a control electrode having an electrode for selectively controlling the passage of the developer through the gate in accordance with the control electrode. In an image forming apparatus in which a developer is selectively passed through the gate to record a desired image by controlling supply according to data, the gate formed on the control electrode is two-dimensionally arranged. The opposing electrode is divided and configured to correspond to each of the two-dimensionally arranged gates, and the divided counter electrode has a constant flying amount of the developer. So that each different potential, or supply time is controlled An image forming apparatus comprising Rukoto. 2. The carrier according to claim 1, wherein the carrier carries the developer on a cylindrical surface for transporting the developer, and the carrier depends on a distance to a counter electrode through a gate formed on the control electrode. 2. The image forming apparatus according to claim 1, wherein a supply potential or a supply time is controlled. 3. A method according to claim 1, further comprising: supplying a potential for causing the developer to fly periodically to the divided counter electrode, and supplying the potential for causing the developer to fly to the divided counter electrode. 2. The image forming apparatus according to claim 1, wherein the flying developer is narrowed down by controlling the supply of a potential lower than the potential for flying the developer to the divided counter electrode adjacent to the developer. 4. A carrier for supporting a developer charged to a predetermined polarity, a counter electrode disposed opposite to the carrier, and a developer passing between the carrier and the counter electrode. And a control electrode having an electrode for selectively controlling the passage of the developer through the gate in accordance with the control electrode. In an image forming apparatus in which a developer is selectively passed through the gate to record a desired image by controlling supply according to data, the gate formed on the control electrode is two-dimensionally arranged. The counter electrode is divided and configured to correspond to each of the two-dimensionally arranged gates, and is provided so as to sandwich the arranged gate. Different supply potentials And, the image forming apparatus characterized by appropriate deflection control the flying direction of the developer. 5. A carrier for carrying a developer charged to a predetermined polarity, a counter electrode disposed opposite to the carrier, and a developer passing between the carrier and the counter electrode. And a control electrode having an electrode for selectively controlling the passage of the developer through the gate in accordance with the control electrode. In an image forming apparatus that records a desired image by selectively passing a developer through the gate by controlling supply according to data, the gate formed on the control electrode is two-dimensionally arranged. The opposing electrode is divided corresponding to each of the two-dimensionally arranged gates, and the divided opposing electrodes are arranged so that the distance to the carrier is constant. An image forming apparatus comprising: 6. An image forming apparatus according to claim 5, wherein said divided opposing electrodes are arranged so that their surfaces are substantially perpendicular to the toner flying direction.