JPH10315528A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a constant image at all times on the entire surface of a print region by performing good print control of toner at all times on the entire surface of the print region thereby performing constant toner flying control all times on the entire surface of the print region. SOLUTION: Only during the time when a potential for passing toner 21 through a gate 29 is not applied from a control power supply 31, an external force (vibration or electric force) for sustaining or weakening the adhesion between toners 21 carried on a toner carrier 22 or the adhesion between the toner 21 and the toner carrier 22 or sustaining the adhesion within a range for controlling the toner 21 as required is imparted. Since an external force, for sustaining the adhesion between toners 21 or the adhesion between the toner 21 and the toner carrier 22 not to have any effect on the printing is applied in a time region other than the ON potential applying time, a good control of toner is ensured at all times on the entire surface of the print region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to digital copiers and facsimile-equipped printing units, digital printers, plotters, etc., and forms an image on a recording medium by flying a developer. Related to the device.

[0002]

2. Description of the Related Art In recent years, as an image forming apparatus for outputting an image signal as a visible image on a recording medium such as paper, an electric field is applied by applying an electric field to charged particles as disclosed in Japanese Patent Application Laid-Open No. Hei 4-290758. Image formation in which a latent image is formed directly on a recording medium bowl by causing charged particles to adhere to a recording medium by changing a potential applied to a control electrode including a plurality of through holes arranged in a flight path by causing A device has been proposed.

In the above-mentioned prior art, toner flying control is performed by using a control electrode for applying a potential corresponding to image information to a plurality of electrodes as the control electrode. Although the above-mentioned prior art describes the above-described control electrode and control method, the control electrode has a different configuration from the present invention, and the control electrode has many problems as described below.

[0004]

In an image forming apparatus of the type typified by the above prior art, control means for controlling the passage of charged particles through a gate is used. An image forming apparatus of the type described in the prior art described above controls the amount of flying toner by an electric field formed between the gate and the carrier. Therefore, if the applied electric field and the electric sensitivity of the toner to the electric field are not always constant, even if a constant electric field is applied, a constant toner flight cannot be obtained, and a good image cannot be obtained.

[0005] In the case of ordinary image data, for example, when the image forming apparatus is a page printer, the printing frequency tends to be high at the center and low at the edges in the longitudinal direction of the carrier. For this reason, there is a strong tendency that the toner carried at the end remains held by the carrier, and the toner at the center tends to be constantly replaced. Therefore, the toner carried on the edge tends to cause aggregation, and the flying sensitivity tends to be lower for the same electric field, that is, the toner is less likely to fly than the toner carried on the center. Therefore, in addition to the drawbacks such as a decrease in the density at the end portions, the drawbacks such as the halftone reproducibility being different between the end portions and the center portion are caused.

This tendency is more conspicuous in a color image forming apparatus. For example, in the case of mainly printing image data of a color which is not frequently used, the toner of the color having a low frequency is applied on the surface of the carrier. As a result, the flight sensitivity is lowered, and a sufficient density cannot be obtained, and a desired color reproducibility cannot be obtained. In order to avoid this problem, it is necessary to use means for preventing the toner from aggregating on the surface of the carrier. For example, an oscillating electric field is always generated between the carrier and the control electrode as in the above-described conventional technique. By vibrating the toner, aggregation of the toner is prevented.

However, according to this method, when a potential (hereinafter referred to as an ON potential) that causes the gate to pass through the toner is applied, the oscillating electric field always synchronizes with the ON potential, The oscillating electric fields must always be in phase. For this reason, a synchronous circuit of the ON potential and the oscillating electric field is separately required, and an adjusting mechanism for finely adjusting the paper feed or the like in accordance with the timing of the ON potential is further required.・ Increase in cost is inevitable.

This disadvantage is because the electric field generated by the ON electric field changes during application of the ON electric potential so as to affect image formation, depending on the phase and frequency of the oscillating electric field used. In order to prevent the change of the electric field from being influenced by the phase and frequency of the oscillating electric field, besides synchronizing the phase and the frequency as described above, the frequency of the oscillating electric field is made much larger than the ON potential. It is possible.

However, if the frequency used is large, the oscillating electric field becomes electric noise and leaks to the outside, causing a malfunction of the image forming apparatus or other devices connected to the image forming apparatus or other devices arranged in the vicinity. This may cause malfunction of the equipment, and in the worst case, may cause a failure or an accident. For this reason, it is necessary to shield the printed portion, and it is unavoidable to further increase the number of parts and increase the size and cost of the apparatus.

An object of the present invention is to solve the above-mentioned problems, and to maintain the adhesion between toners or between a toner and a carrier without affecting printing in a time region other than the ON potential application time. It is an object of the present invention to provide an image forming apparatus which can always perform good toner control over the entire printing area by applying an external force for the purpose.

Another object of the present invention is to provide an image forming apparatus in which the above-mentioned external force is not applied during the application of the ON potential, so that the external force does not affect the flying control and printing of the toner.

Further, the present invention provides an image forming apparatus capable of maintaining the toner so that a constant toner flying control can always be performed over the entire printing area by the above-described control, thereby enabling a constant image formation to be always performed over the entire printing area. The purpose is to do.

[0013]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a supply unit having a carrier for carrying a developer of at least one color; a counter electrode disposed to face the carrier; An insulating substrate disposed between the carrier and the counter electrode, a plurality of gates provided on the insulating substrate to serve as a passage portion of the developer, and at least a plurality of gates provided around the plurality of gates A control electrode including one or more electrode groups;
At least a control circuit comprising control circuit means capable of applying a predetermined potential corresponding to at least image data to the individual electrodes of the control electrodes, wherein the control means controls a predetermined potential to a corresponding electrode of the electrode group. In the image forming apparatus that controls the passage of the developer through the gate by applying a pressure, and forms an image on the surface of the recording medium conveyed between the control electrode and the counter electrode. Maintaining the adhesive force between the developing agents carried on the carrier or the adhesive force between the carrier and the developer only at the time of applying a potential that can pass the developer to the gate or The image forming apparatus is characterized in that the adhesive force is weakened or an external force is applied so that the adhesive force is maintained within a range where desired control of the developer is possible.

According to a second aspect of the present invention, in the image forming apparatus, the developer carried by the carrier vibrates due to the external force.

According to a third aspect of the present invention, the external force is an electric force having a frequency component, and it is difficult to move the developer to the recording medium by the electric force. An image forming apparatus.

According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising: a supply unit having a carrier for carrying a developer of at least one color;
A counter electrode facing the carrier, a high-voltage power supply for supplying a high voltage that generates a potential difference between the carrier and the counter electrode, and a high-voltage power supply disposed between the carrier and the counter electrode; An insulating substrate, a plurality of gates provided on the insulating substrate and serving as a passage portion of a developer, and a first electrode group including one or more electrodes around the plurality of gates and a second electrode group. A control electrode comprising at least two or more electrode groups including an electrode group, control means comprising control circuit means for supplying a predetermined potential state to the electrodes of the first electrode group and the second electrode group, and the control electrode The recording medium conveyed between the opposed electrodes, and a predetermined potential corresponding to image data is applied to the corresponding electrodes of the first and second electrode groups by the control circuit means, and the gate of the developer is applied to the gate. Image formation that forms an image on the upper recording medium by controlling the passage In the arrangement, the control means is configured to control the potential applied to the electrode group facing the carrier, or the electrode group facing the carrier arranged so that the number of electrodes is smaller than that of the electrode group facing the counter electrode. Is controlled so that the external force can be applied to the developer carried on the carrier.

According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising: a supply unit having a carrier for carrying a developer of at least one color;
A counter electrode disposed to face the carrier, an insulating substrate disposed between the carrier and the counter electrode, and a plurality of gates provided on the insulating substrate and serving as passage portions for the developer. And at least one or more electrode groups provided around the plurality of gates, and at least a part of each of the electrodes and at least a part of each of the electrode groups provided on the gates is directly or directly on the carrier. A control electrode disposed between the electrode group and the carrier with a shield electrode comprising an electrode having an opening provided to be electrically exposed, and at least individual electrodes of the control electrode corresponding to at least image data. At least control means comprising control circuit means capable of applying a predetermined potential, and applying the predetermined potential to the corresponding electrode of the electrode group by the control means to pass the developer through the gate. In the image forming apparatus for forming an image on the surface of the recording medium conveyed between the control electrode and the counter electrode, the control electrode faces the electrode group facing the carrier, or faces the counter electrode. Including the electrode group opposed to the carrier arranged so that the number of electrodes is smaller than the electrode group, the potential to be applied to the shield electrode is applied to the developer in which the external force is carried on the carrier. An image forming apparatus is characterized in that the image forming apparatus is controlled so that the image can be provided.

According to a sixth aspect of the present invention, there is provided an image forming apparatus comprising: a supply unit having a carrier for carrying at least a plurality of color developers; a counter electrode disposed to face the carrier; And an insulating substrate disposed between the insulating substrate, a plurality of gates provided on the insulating substrate and serving as a passage portion of the developer, and at least one or more electrodes provided around the plurality of gates And a control electrode comprising at least:
At least a control circuit comprising control circuit means capable of applying a predetermined potential corresponding to at least image data to the individual electrodes of the control electrodes, wherein the control means controls a predetermined potential to a corresponding electrode of the electrode group. In the color image forming apparatus that controls the passage of the developer through the gate by applying the control electrode to form a color image on the surface of the recording medium conveyed between the control electrode and the counter electrode, the control electrode is An electrode group opposed to the carrier, or an electrode group opposed to the carrier arranged so that the number of electrodes is smaller than that of the electrode group opposed to the counter electrode, and the control means includes: The potential applied to the electrode group facing the carrier, or the electrode group facing the carrier, which is arranged so that the number of electrodes is smaller than that of the electrode group facing the counter electrode, is set to the external force. An image forming apparatus and controls to allow imparted to the developer carried on the carrier.

According to a seventh aspect of the present invention, in the image forming apparatus, the potential having the frequency component is supplied to the carrier, and at least the control means causes the developer carried on the carrier to pass through the gate. During the supply of the potential, the potential of the carrier is switched to a potential that eliminates a phase difference and a frequency difference between the potential of the electrode group and the potential of the electrode group so that a desired carrier can be controlled. A switching means for switching the potential so as to apply a DC potential as the potential of the carrier when the DC potential is applied to the electrode group; and Is applied to the developer.

In the image forming apparatus according to the present invention, when the potential having the frequency component is supplied to the carrier, the control means may control the developer carried on the carrier to pass the gate through the gate. An image forming apparatus, wherein the external force is applied to the developer by applying a potential having at least the same or substantially the same frequency component as the potential having the frequency component. is there.

According to a ninth aspect of the present invention, in the image forming apparatus, the external force is a mechanical minute vibration and the control is performed on the minute vibration.

According to the image forming apparatus of the first aspect, O
In the time region other than the application time of the N potential, an external force is applied to maintain the adhesion between toners or between the toner and the carrier so as not to affect printing, so that good toner is always provided over the entire printing region. Can be controlled. At the same time, during the application of the ON potential, the above-described external force is not applied, so that the external force does not affect the flying control and printing of the toner. Further, the above control enables the toner to be maintained so that a constant toner flying control can be always performed over the entire printing area, so that a constant image can be always formed over the entire printing area.

According to the image forming apparatus of the present invention, the above-described control can be obtained most easily because the adhesion force is maintained in a good range by vibrating the toner on the carrier.

According to the image forming apparatus of the third aspect, the vibration can be easily adjusted and the control can be easily performed, so that the apparatus can be made dense and simple in order to obtain the vibration.

According to the image forming apparatus of the present invention, since the potential of the electrode arranged on the side of the carrier is controlled so that the external force can be applied to the toner carried on the carrier. The oscillating electric field as the external force is more efficiently formed, and the number of switching circuits for switching the electrode potential is minimized, so that the number of components can be reduced and the size and cost of the device can be reduced.

According to the image forming apparatus of the present invention, the shield electrode is arranged as the control electrode, and the potential applied to the shield electrode can be applied to the toner on which the external force is carried on the carrier. With such control, the potential switching means can be further reduced, and at the same time, the withstand voltage of the potential switching means can be reduced, so that the number of parts and the size and cost of the apparatus can be further reduced.

According to the image forming apparatus of the present invention, since the above-described control is performed also in the color image forming apparatus, it is possible to maintain the infrequently used toner on the carrier so that good flight control can always be performed. Therefore, it is possible to realize a color image forming apparatus that can always reproduce desired colors and does not cause image deterioration. According to the configuration of claim 7, ON is performed as described above.
Since the AC component is relatively negligible with respect to the AC potential applied to the carrier, toner control is not affected by the AC component.

According to the image forming apparatus of the present invention, since the oscillating electric field is not formed only in the area facing the gate where the toner is required to fly, the effect of the oscillating electric field can be maximized.

According to the image forming apparatus of the ninth aspect, since the mechanical vibration using PZT is used as the vibration, the potential used is low, and the increase in the cost of the power supply is minimized.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 is a sectional view of a printer equipped with an image forming apparatus according to an embodiment of the present invention. An outline of each element in FIG. 1 will be described with reference to FIG. In the following description, an image forming apparatus having a configuration corresponding to a negatively charged toner will be described in detail. However, when a positively charged toner is used, the polarity of each applied voltage is appropriately set accordingly. do it.

As shown in FIG. 2, the toner supply unit 2 and the printing unit 3
And an image forming unit 1 having the following. The image forming section 1 visualizes an image corresponding to an image signal on a sheet as a recording medium using toner as a developer. In other words, the present image forming apparatus directly forms an image on paper by controlling the flying of the toner based on an image signal while causing the toner to fly and adhere to the paper. On the paper entry side of the paper to the image forming unit 1,
A paper feeding device 10 is provided.

The paper feeding device 10 is provided with a paper 5 as a recording medium.
, A pickup roller 6 for feeding out the paper 5 from the paper cassette 4, and a paper feed guide 7 for guiding the supplied paper 5. Further, the paper feeding device 10 includes a paper feeding sensor (not shown) for detecting that the paper 5 has been supplied. The pickup roller 6 is driven to rotate by a driving device (not shown).

On the paper output side of the sheet from the image forming section 1, a fixing section 11 for fixing the toner image formed on the sheet 5 in the image forming section 1 to the sheet 5 by heating and pressing is provided. Is provided. The fixing unit 11 includes the ripening roller 1
2, a heater 13, a pressure roller 14, a temperature sensor 15, and a temperature control circuit 80. The heating roller 12 is made of, for example, an aluminum tube having a thickness of 2 mm. Heater 13
Is composed of, for example, a halogen lamp and is built in the heating roller 12. The pressure roller 14 is made of, for example, a silicone resin.

The heating roller 12 and the pressure roller 14, which are provided opposite to each other, are provided with springs or the like (not shown) at both ends of each shaft, for example, 2 kg so that the paper 5 can be pressed therebetween. Is applied. The temperature sensor 15 measures the temperature of the surface of the heating roller 12. The temperature control circuit 80 is controlled by the main control unit, controls ON / OFF of the heater 13 based on the measurement result of the temperature sensor 15, and keeps the temperature of the surface of the heating roller 12 at, for example, 150 ° C.

The fixing unit 11 has a paper discharge sensor (not shown) for detecting that the paper 5 has been discharged.
The materials of the heating roller 12, the heater 13, the pressure roller 14, and the like are not particularly limited. Further, the temperature of the surface of the heating roller 12 is not particularly limited. Further, the fixing unit 11 may be configured to fix the toner image by heating or pressing the sheet 5.

Although not shown, a discharge roller for discharging the sheet 5 processed by the fixing unit 11 onto a discharge tray, and a discharged sheet 5 A receiving tray is provided. The heating roller 12, the pressure roller 14, and the paper discharge roller are rotationally driven by a driving device (not shown). Image forming unit 1
The toner supply unit 2 includes a toner container 20 containing a toner 21 as a developer, a toner carrier 22 as a cylindrical carrier (sleeve) that carries the toner 21 by magnetic force, and A storage tank 20 is provided inside, and charges the toner 21 and a toner carrier 22.
The doctor blade 23 regulates the thickness of the toner layer carried on the outer peripheral surface of the doctor blade.

The doctor blade 23 holds the toner carrier 2
2 is provided on the upstream side in the rotation direction such that the distance from the outer peripheral surface of the toner carrier 22 is, for example, 60 μm. The toner 21 is, for example, a magnetic toner having an average particle diameter of 6 μm, and is charged by the doctor blade 23 so that the charge amount is, for example, −4 μC / g to −5 μC / g. The distance between the doctor blade 23 and the toner carrier 22 is not particularly limited. Further, the average particle size and the charge amount of the toner 21 are not particularly limited.

The toner carrier 22 is driven by a driving device (not shown), and rotates in the direction of arrow A in the figure at a speed of, for example, 80 mm / sec on the surface. Further, the toner carrier 22 is grounded, and a position facing the doctor blade 23 inside the toner carrier 22;
A magnet (not shown) is arranged at a position facing the control electrode 26 (described later). Thereby, the toner carrier 2
Reference numeral 2 is such that the toner 21 can be carried on its outer peripheral surface. Further, the toner 21 carried on the outer peripheral surface of the toner carrier 22 forms ears at positions corresponding to the above positions on the outer peripheral surface. The toner carrier 2
The rotation speed of No. 2 is not particularly limited. Also,
Instead of supporting the toner 21 by the magnetic force, the toner carrier 22 may be configured to support the electric force or the electric force and the magnetic force.

The printing unit 3 of the visual image forming unit 1 has a thickness
mm, an opposing electrode 25 facing the outer circumferential surface of the toner carrier 22, a high-voltage power supply 30 for supplying a high voltage to the opposing electrode 25, and a control provided between the toner carrier 22 An electrode 26, a neutralizing brush 28, a neutralizing power source 17 for applying a neutralizing potential to the neutralizing brush 28, a charging brush 8 for charging the paper 5, a charging power source 18 for applying a charging potential to the charging brush 8, a dielectric belt 24, Support members 16 a and 16 b for supporting the dielectric belt 24 and a cleaner blade 19 are provided.

The counter electrode 25 is connected to the toner carrier 22.
Is provided so that the distance from the outer peripheral surface thereof is, for example, 1.1 mm. The dielectric belt 24 is made of polyvinylidene fluoride (PVDF) as a base material and has a volume resistivity of 1010 Ω · c.
m, and the thickness is 75 μm. The dielectric belt 24 is driven by a driving device (not shown), and rotates at a speed of, for example, 30 mm / sec on its surface in the direction of the arrow in the figure.

A high voltage of, for example, 2.3 kV is applied to the counter electrode 25 by a high voltage power supply (control means) 30. That is, the toner 21 carried on the toner carrier 22 is applied between the counter electrode 25 and the toner carrier 22 by the high voltage applied from the high voltage power supply unit 30.
The electric field required to fly in the direction is provided.

The static elimination brush 28 is provided on the downstream side of the control electrode 26 in the rotation direction of the dielectric belt 24 so as to be in pressure contact with the dielectric belt 24. The neutralizing brush 28 is applied with a neutralizing potential of 2.5 kV by the neutralizing power source 17 to neutralize unnecessary charges existing on the surface of the dielectric belt 24. The cleaning blade 19 removes the toner 21 when an unexpected situation such as a paper jam (paper jam) occurs and the toner 21 adheres to the surface of the dielectric belt 24, and removes the toner 21 from the toner back surface. 21 to prevent contamination. The material of the counter electrode 25 is not particularly limited. Also, the counter electrode 25
The distance between the toner carrier 22 and the toner carrier 22 is not particularly limited. Furthermore, the rotation speed of the counter electrode 25 and the applied voltage are not particularly limited.

Although not shown, the present image forming apparatus includes:
As a control circuit, a main control unit that controls the entire image forming apparatus, an image processing unit that converts the obtained surface image data into a format of image data to be printed, and an image memory that stores the converted image data. And an image forming control unit for converting image data obtained from the image processing unit into image data to be given to the control electrode 26.

The control electrode 26 is parallel to the tangential direction of the surface of the counter electrode 25 and faces the counter electrode 25 in two directions.
It has a structure that allows the toner flow from the toner carrier 22 to the counter electrode 25 to pass therethrough.
The electric field applied to the surface of the toner carrier 22 changes according to the potential supplied to the control electrode 26, and the flying of the toner 21 from the toner carrier 22 to the counter electrode 25 is controlled. The control electrode 26 is provided so that the distance from the outer peripheral surface of the toner carrier 22 is, for example, 100 μm, and is fixed by a support member (not shown).

As shown in FIG. 3, the control electrode 26 includes an insulating substrate 26a, a high-voltage driver (not shown),
Independent ring-shaped conductors, that is, ring-shaped electrodes 27
… Consisting of The substrate 26a is made of, for example, a polyimide resin and has a thickness of 25 μm. The substrate 26a has holes to be gates 29 described later. The ring-shaped electrodes 27 have a thickness of, for example, 18
μm copper foil, provided around the above hole,
They are arranged according to a predetermined arrangement.

The opening of each hole has a diameter of, for example, 160
μm, and serves as a passage portion for the toner 21 flying from the toner carrier 22 to the counter electrode 25. Hereinafter, this passing portion is referred to as a gate 29. still,
The distance between the control electrode 26 and the toner carrier 22 is not particularly limited.

Each ring-shaped electrode 27 is provided with an opening having an opening diameter of 200 μm. Gate 2
9 and the size of the substrate 26a and the ring-shaped electrode 27 ...
The material, thickness, etc. of the material are not particularly limited. For example, 2560 holes are formed in the gates 29, that is, in the ring-shaped electrodes 27. Each of the ring-shaped electrodes 27 has a power supply line 41 and a high-voltage driver (not shown).
And is electrically connected to the control power supply unit 31 via the.
The number of the ring-shaped electrodes 27 is not particularly limited.

The surface of the ring-shaped electrodes 27 and the surface of the power supply line 41 are covered with an insulator layer 26b having a thickness of 30 μm. ..., insulation between the ring-shaped electrodes 27 that are not connected to each other and the power supply lines 41, and insulation between the toner carrier 22 and the counter electrode 25 are ensured. The material and thickness of the insulator layer are not particularly limited.

The ring electrodes 27 of the control electrode 26 include:
A pulse corresponding to an image signal, that is, a voltage is applied by a control power supply unit (control means) 31. That is, the control power supply unit 3
1 applies, for example, 150 V to the ring-shaped electrodes 27... When the toner 21 carried by the toner carrier 22 passes in the direction of the counter electrode 25, and otherwise applies −150 V as described later. An oscillating potential having a frequency of 1 kHz and an amplitude of 200 V is applied to the DC component of the above.

As described above, when the potential applied to the control electrode 26 is controlled in accordance with the image signal, and the paper 5 is disposed on the surface of the counter electrode 25 facing the toner carrier 22, the paper 5
A toner image corresponding to the image signal is formed on the surface of the toner image. still,
The control power supply unit 31 is controlled by a control signal of a control electrode sent from an image forming control unit (not shown).

The above-described image forming apparatus can be used not only as a printer for outputting from a computer or a word processor but also as a printing portion of a digital copy. The forming operation is performed using FIG.

First, for example, when a document to be copied is placed on the image reading section and a copy start button (not shown) is operated, the main control section having received this input starts an image forming operation. That is, a document image is read by the image reading unit, the image data is processed by the image processing unit, the image data stored in the image memory stored in the image memory is transferred to the image forming control unit, The image forming control unit starts converting the input image data into a control signal from a control electrode to be applied to the control electrode 26.

When the image forming control unit obtains a control signal from a predetermined amount of the control electrodes, a driving device (not shown) is operated, and the pickup roller 6 shown in FIG. The paper 5 in the cassette 4 is sent out toward the image forming unit 1, and a normal paper feeding state is detected by the paper feeding sensor. The sheet 5 sent out by the pickup roller 6 is transported between the charging brush 8 and the support member 16.

The same potential as that of the counter electrode 25 is applied to the support member 16a by the high voltage power supply 30. A charging power source 18 applies a charging potential of 1.2 kV to the charging brush 8. The paper 5 is supplied with a charge due to the potential difference between the charging brush 8 and the support member 16a, and is conveyed to the surface of the printing unit 3 of the image forming unit 1 facing the toner carrier 22 of the dielectric belt 24 while being electrostatically attracted. You. The predetermined amount of the control signal from the control electrode differs depending on the configuration of the image forming apparatus.

After that, the image forming control unit supplies the control signal from the control electrode to the control power supply unit 31.
The supply of the control signal from the control electrode is performed at a timing synchronized with the supply of the paper 5 to the printing unit 3 by the charging brush 8 described above. The control power supply unit 31 controls a high voltage applied to each ring-shaped electrode 27 of the control electrode 26 based on the control signal from the control electrode. That is, an oscillating potential having a frequency of 1 kHz and an amplitude of 200 V is applied to a DC component of 150 V or -150 V from the control power supply unit 31 to a predetermined ring-shaped electrode 27 as appropriate, and the electric field near the control electrode 26 is controlled. That is, at the gate 29 of the control electrode 26, the prevention of the flying of the toner 21 from the toner carrier 22 to the counter electrode 25 and the release thereof are appropriately performed according to the image data.

As a result, the movement of the dielectric belt 24 on the surface of the counter electrode 25 causes a distance of 30 mm / s toward the paper output side.
A toner image corresponding to the image signal is formed on the paper 5 moving at the speed of ec. Paper 5 on which toner image is formed
Is separated from the dielectric belt 24 by the curvature of the support member 16b, and is conveyed to the fixing unit 11;
At 1, the toner image is fixed on the paper 5. The paper 5 on which the toner image has been fixed is discharged onto a paper tray by a paper discharge roller, and a normal discharge is detected by a paper discharge sensor. Based on this detection operation, the main control unit determines a normal end of the printing operation.

By the above image forming operation, a good image is formed on the paper 5. In the present image forming apparatus, an image is formed directly on the paper 5, so that a visual object such as a photoconductor or a dielectric drum used in a conventional image forming apparatus is not required. Therefore, the transfer operation of transferring the image from the visualized object to the sheet 5 is omitted, so that the image does not deteriorate. For this reason, the reliability of the device is improved. In addition, since the configuration of the apparatus is simplified and the number of parts is reduced, the size and the cost can be reduced.

Whether the image forming apparatus of the above embodiment is used as a print portion of an output terminal of a computer or a digital copy,
Although there is a difference in the image signal to be processed and the exchange, the image forming operation method itself has no difference. As described above, the toner carrier 22 is grounded, while the opposing electrode 25 and the support member 16a are 2.3 k
V, a high voltage of 1.2 kV is applied to the charging brush 8.

Accordingly, a negative charge is supplied to the surface of the sheet 5 conveyed between the charging brush 8 and the dielectric belt 24 due to a potential difference between the charging brush 8 and the support member 16a. When a negative charge is supplied, the paper 5 is moved directly below the gate 29 by the movement of the dielectric belt 24 while being attracted to the dielectric belt 24 by the electrostatic force of the charge. The electric charge on the surface of the dielectric belt 24 is attenuated with time until it reaches just below the gate 29, and the surface potential becomes 2 kV due to the electric potential of the counter electrode 25.

In this state, the control power supply unit 31 controls the ring-shaped electrode 27 of the control electrode 26 so that the toner 21 carried on the toner carrier 22 passes in the direction of the counter electrode 25.
Is applied, and when the toner 21 does not pass through the gate 29, an oscillating potential having a frequency of 1 kHz and an amplitude of 200 V is applied to a DC component of -150 V. In this manner, an image is directly formed on the surface of the sheet 5 while the sheet 5 is attracted to the dielectric belt 24. Note that, in the above description, the control electrode 2
6, the potential applied to the ring-shaped electrodes 27 is 150 V. However, the potential is not particularly limited as long as the desired flight control of the toner 21 can be performed.

Similarly, the potential applied to the counter electrode 25, the potential applied to the charging brush 8, and the surface potential of the sheet 5 immediately below the gate 29 are also limited as long as the toner can perform the desired flight control of −21. is not. The potential applied to the ring electrodes 27 of the control electrode 26 to prevent the passage of the toner 21 is not particularly limited as long as it does not deviate from the scope of the present invention.

The configuration of the control electrode 26 used in the above embodiment will be described. Gate 2 in FIG.
FIG. 5 shows an example of the potential control for the ring-shaped electrode 27-n in the case where the toner 21 is caused to fly only to 9-n.

In the potential control, as shown in FIG. 5, the ON potential of the ring-shaped electrode 27-n is set to 15 by the ON signal of the image signal.
Although 0 V is applied by being switched by the control power supply unit 31, the image signal is OFF, and the potential of the other ring-shaped electrode 27 disposed on the other gate 29 is the oscillating potential described above.

During the time when the ON potential is applied, a desired DC electric field is generated between the toner carrier 22 and the toner carrier 22 so that the toner 21 can fly well. can get. On the other hand, in the time period in which the ON potential is not applied, an oscillating electric field is applied to the toner 21 carried on the toner carrier 22. The toner 21 carried on the toner carrier 22 vibrates due to the oscillating electric field, and the toners 21 or the toner carrier 22
The adhesion between the toner 21 and the toner 21 and the toner carrier 22 does not increase due to the aggregation of the toner 21 and the toner 21.

At the same time, the oscillating electric field is
Although it is possible to vibrate the toner 21 carried on the sheet 5 as described above, the electric field passing through the gate 29 and flying on the sheet 5 is insufficient, and therefore, the toner carrier 2
2 does not pass through the gate 29. This oscillating electric field causes the toner 2 as described above.
1 is slightly vibrated, and the toner 21 on the toner carrier 22 can be maintained in a good state.

The increase in the adhesive force is attributed to the fact that the toner 21 is supported on the toner carrier 22 and absorbs moisture in the air, for example, to start agglomeration. In order to prevent the adhesive force from becoming unnecessarily strong, it is conceivable to send dry air, for example, in addition to the above-mentioned vibration. However, a problem such as scattering of the toner 21 occurs, and the cost becomes complicated. Trigger up.

Therefore, it is preferable to vibrate the toner 21 in order to prevent the adhesion force from increasing as described above. If the control as in the present embodiment is not performed, the frequency at which the toner 21 flies is low in a portion where the toner 21 flies relatively low, for example, at the end of the toner carrier 22 in the longitudinal direction, and the toner 21 The state of being held on the carrier 22 continues for a relatively long time. In this case, as described above, the adhesion between the toners 21 or between the toner 21 and the toner carrier 22 is increased, so that the flying becomes difficult and the image is not lost.
2, the flying amount of the toner 21 is different between the center part and the end part, and the image density is different between the end part and the center part. In addition, it is difficult to reproduce halftone.

The above problem is more conspicuous in the case of a color image forming apparatus than in the case of a monochrome image forming apparatus as in this embodiment. The color image forming apparatus is, for example, an image forming unit 1 including a plurality of toner supply units 2a, 2b, 2c, 2d... And printing units 3a, 3b, 3c, 3d.
a, 1b, 1c, 1d,..., and color toners, for example, yellow, magenta, cyan, and black as shown in FIG. May be formed. In FIG. 6, the image forming units 1a corresponding to yellow, magenta, cyan, and black, respectively, according to the present invention,
1b, 1c, and 1d are arranged, and a color image is formed based on color image data.

Other components may be the same as those in FIG. In the case of the color image forming apparatus, it is expected that the frequency of use of one color toner 21 becomes extremely low depending on the characteristics of the image data used. For example, when only the magenta toner 21 is not used depending on the image data, the magenta toner remains supported on the toner carrier 22 and the adhesion between the toners or between the toner and the toner carrier is easily increased as described above. The tendency is higher. If magenta printing is performed in this state, the problem that the magenta toner does not fly properly and the desired color cannot be reproduced easily occurs. In order to avoid the above-mentioned problems, the toner 21 is always carried on the toner carrier 22 and the adhesion between the toners 21 or the toner 21 and the toner carrier 2
Means for vibrating the toner 21 is required so that the adhesive force of No. 2 does not increase.

As this means, there has been proposed a method of applying an oscillating electric field between the toner carrier and the control electrode as in the above-mentioned technique. However, the oscillating electric field is applied to the toner 21 by the gate 2
9 must always have the same phase as the ON potential that causes flight. For example, as shown in FIG. 7, an oscillating potential is applied to the toner carrier 22 and a DC ON potential of 150 V is applied to the control electrode, and a DC OFF potential is also applied. When a voltage of -200 V is applied, the phase of the vibration electric field formed with the toner carrier 22 may be shifted every time the voltage is applied.
Since no electric field is applied, the desired flying control of the toner 21 becomes impossible, and good image formation cannot be performed.

For this purpose, the frequency of the oscillating potential to be applied must be the same as the frequency of the ON potential applied to the ring-shaped electrode 27, and only a single frequency is used in order to prevent the above-mentioned adhesive force of the toner 21 from increasing. It is not suitable because it cannot be used. For example, even if it is possible to avoid the increase in the adhesion of the toner 21 by the single frequency, the phase of the ON potential must always be the same as that of the ON potential. Means for adjusting the timing of the ON potential and the timing of each control, for example, means for finely adjusting the paper feed, etc., are separately required, and the increase in the number of parts and the increase in size and cost of the apparatus are inevitable.

In order to prevent the flying electric field due to the ON potential from being influenced by the phase and frequency of the oscillating electric field, besides synchronizing the phase and frequency as described above, in order to avoid this problem, the above-mentioned ON potential is set to A method of superimposing and applying the vibration component is considered.

For example, in the control as shown in FIG. 7, it is possible to apply a potential obtained by superimposing a vibration potential having a vibration component having the same phase and the same amplitude as the potential of the toner carrier 22 on the ON potential of 150 V as the ON potential. The state is shown in FIG. In FIG. 14, an AC potential having a frequency of 1 kHz and an amplitude of 200 V is applied to the toner carrier 22, and a potential obtained by superimposing the AC potential on the ON potential is applied. Therefore, during the application of the ON potential, the potential difference from the toner carrier 22 is always a potential difference of only the DC component, so that a constant potential difference can always be maintained. In the control as shown in FIG. 14, there is no need for the above-mentioned synchronization and there is no relative AC component with the toner carrier 22, so that good control of the toner 21 is possible.

In order to prevent the flying electric field due to the ON potential from being influenced by the phase and frequency of the oscillating electric field, in addition to synchronizing the phase and frequency as described above, the frequency of the oscillating electric field is compared with the ON potential. It can be very large. For example, in the above embodiment, if the ON potential is 200 μsec, the frequency which is several times the ON potential is
For example, a frequency of about 10 kHz is required.

However, when the frequency used is large, the oscillating electric field becomes electric noise and leaks to the outside, causing a malfunction of the image forming apparatus or other devices connected to the image forming apparatus or other devices arranged around the image forming apparatus. Malfunctions, and in the worst case, it may cause a failure or an accident. For this reason, it is necessary to shield the printed portion, and it is unavoidable to further increase the number of parts and increase the size and cost of the apparatus. In the present embodiment, since the above-mentioned oscillating electric field is not applied when the ON potential is applied as described above, all of the above problems can be avoided.

Further, in the above embodiment, the toner 21 flying control of the gate 29 has been described in the case of the single drive in which each gate 29 is controlled by one electrode, but the control electrode 26 by the matrix control as shown in FIG. 8 is used. In this case, the present invention can be similarly applied, and good image formation can be achieved.

In FIG. 8, band electrodes 27a and 27b are arranged in place of the ring electrodes 27. A band electrode 27a is arranged on the toner carrier 22 side of the control electrode 26, and a band electrode 27b is arranged on the counter electrode 25 side.
In the case of the control electrode 26 as shown in FIG. 8, the switching circuit used as the potential switching means is reduced to 1/4 as compared with the control electrode of FIG. 3, so that the number of parts can be reduced and the size and cost of the device can be reduced. .

Further, in the control electrode 26 shown in FIG. 8, the above-described control of the oscillating potential is performed on the strip electrode 27a arranged on the toner carrier 22 side. For example, the gate 29-n
FIG. 12 shows the control of each of the strip electrodes 27a and 27b when printing is performed.

As shown in FIG. 12, the oscillating potential is applied to the belt-like electrode 27a on the toner carrier 22 side, and the ON potential is switched to 150 V, which is a DC ON potential. The circuit for switching the potential including the vibration component is more complicated than the circuit for switching a simple DC potential.
As compared with the control of the oscillating potential, the number of necessary switching circuits can be reduced, and the number of components can be reduced, and the size and cost of the device can be reduced.

At the same time, the strip electrode 2 close to the toner carrier 22
Since the vibration is applied to the electrode 7a, a stronger electric field can be formed with a lower electric field, and the withstand voltage required for the potential switching means is lower than the case where the oscillating electric field is formed by performing the above-described control on the strip electrode 27b. Very suitable from a point of view.

The control electrode 26 shown in FIG. 3 can be formed as shown in FIG. In FIG. 9, a shield electrode 39 having a 240 μm opening on the toner carrier 22 side substantially on the entire surface of the control electrode 26 corresponding to the gate 29.
Has been arranged. When the shield electrode 39 as shown in FIG. 9 is arranged, the above control may be performed on each ring-shaped electrode 27, but the following control is desirable. When the shield electrode 39 is arranged as shown in FIG.
FIG. 10 shows the control in the case where the toner 21 flies to −n.

The ON potential of the ring electrode 27 is set to 150
V, potential that does not cause toner 21 to fly (hereinafter OFF potential)
Is applied according to the image data. On the other hand, the shield electrode 39 applies the above-mentioned vibration having an amplitude of 1 V and 200 V as the vibration potential. When the ON potential is applied to the ring electrode 27, the oscillating potential is switched to a DC potential as shown in FIG. In FIG. 10, -50 V is applied as the DC potential.

In the control as shown in FIG. 10, the switching of the oscillating potential only needs to be performed for the shield electrode 39, so that basically only one switching means is required, and the cost increase required for the switching means is minimized. Can be Although FIG. 9 shows a case where there is one shield electrode 39, the shield electrode 39 may be divided into a plurality.

Also, in the case of the control electrode by the matrix control shown in FIG.
FIG. 13 shows a case where the potential control in this case, for example, the flying of the toner 21 to the gate 29-n is performed.

In FIG. 13, as the oscillating potential applied to the shield electrode 39, a 1-kHz amplitude 200V vibration is applied in the same manner as described above. Also in this case, ON as in the control of FIG.
Only when the potential is applied, the potential of the shield electrode 39 is switched to the DC potential of −50 V which is the potential of the shield electrode 39. The configuration in which the shield electrode 39 is disposed and the oscillating potential is applied to the shield electrode 39 requires less switching means for the potential to be used as compared with the case where the shield electrode 39 is not disposed, and is necessary for the switching means. As the withstand voltage decreases, the number of parts can be reduced, and the size and cost of the device can be reduced.

The above-mentioned control electrodes and the control thereof can be applied to the above-described color image forming apparatus. However, for a color image forming apparatus, the number of control electrodes to be used or switching means for switching the potential of the electrodes is limited. In the case of the above embodiment, the cost is simply increased by a factor of four.
The cost is doubled and the cost can be greatly reduced.

Further, in the above embodiment, the toner carrier 22 is mainly made of GND, and the switching between the oscillating potential and the DC potential is performed by an electrode disposed on the control electrode, for example, the shield electrode 39 or the ring electrode 27 or the strip electrode 27a. , 2
7b. However, the potential applied to each electrode of the control electrode 26 may be controlled so that a DC potential is applied to switch the potential of the carrier between the oscillating potential and the DC potential.

For example, taking the control electrode of FIG. 3 as an example, FIG.
Is possible. In this case, only one means for switching the oscillating potential is basically required, and the increase in circuit cost can be minimized. As shown in FIGS. 5 and 14, it is desirable that the control is such that the vibration component does not affect the ON potential only in the region facing the gate 29 where the toner 21 needs to fly.

Further, in each of the above embodiments, an oscillating electric field is applied to generate a vibration for preventing the toner 21 from increasing the adhesive force on the toner carrier 22.
However, the vibration is not limited to being caused by the above-mentioned oscillating electric field. For example, if a minute vibration can be used in order not to increase the adhesive force, the toner carrier 22 can be vibrated by a piezoelectric element (PZT) or the like.

However, if the toner carrier 22 is constantly vibrated, a standing wave may be generated in the toner 21 on the toner carrier 22 and the flying control of the toner 21 may be difficult. In addition, when the toner carrier is in a belt shape, a standing wave is generated on the carrier, causing the position of the toner carrier 22 to deviate from a predetermined position, so that the toner 21 cannot be controlled to fly as desired. Trigger.

Therefore, even when the toner 21 is vibrated by using PZT, the O is applied to the control electrode 26 as in the above embodiment.
It is necessary to stop the vibration of the PZT at least during the application of the N potential to perform printing in order to perform good printing. When the above-described vibration is applied using PZT, the amplitude of the AC potential used can be smaller than in the case where the above-described oscillating electric field is applied, and the potential switching circuit has a lower withstand voltage. Down is possible and desirable.

In this embodiment, the case where the developer is a toner has been described as an example, but the developer may be an ink or the like. Further, the configuration of the toner supply unit 2 may be a configuration to which an ion flow method is applied. That is, the image forming unit may be configured to include an ion source such as a corona charger. Also in this case, the same operation and effect as described above can be obtained.

In this embodiment, the case where the developer is a toner has been described as an example, but the developer may be an ink or the like. The image forming apparatus according to the present invention includes:
For example, the present invention can be suitably applied to a printing unit of a digital copying machine and a facsimile machine, a digital printer, a plotter, and the like.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and it is a matter of course that the present invention can be appropriately modified and implemented without departing from the scope of the invention.

[0096]

According to the first aspect of the present invention, in the image forming apparatus, the adhesive force between the toners or between the toner and the carrier is maintained so as not to affect the printing in a time region other than the ON potential application time. Since an external force is applied, good toner control is always possible over the entire printing area. ON at the same time
Since the above-described external force is not applied during the application of the potential, the external force does not affect the toner flight control and printing. Further, the above control enables the toner to be maintained so that a constant toner flying control can be always performed over the entire printing area, so that a constant image can be always formed over the entire printing area.

In the image forming apparatus according to the second aspect,
By vibrating the toner on the carrier, the above-mentioned control is obtained most easily because the above-mentioned adhesive force is maintained in a favorable range.

In the image forming apparatus according to the third aspect,
Since the above-mentioned vibration can be easily adjusted and the above-mentioned control can be easily performed, the apparatus can be made dense and simple in order to obtain the above-mentioned vibration.

In the image forming apparatus according to the fourth aspect,
Since the potential of the electrode is controlled so that the external force can be applied to the toner carried on the carrier with respect to the electrode disposed on the carrier side, the oscillating electric field as the external force is more efficiently formed. In addition, the number of switching circuits for switching the electrode potential is minimized, and the number of components can be reduced, and the size and cost of the device can be reduced.

In the image forming apparatus according to the fifth aspect,
The configuration in which a shield electrode is disposed as a control electrode further controls the potential applied to the shield electrode so that the external force can be applied to the toner carried on the carrier. At the same time, the potential switching means can be configured to have a low withstand voltage, so that the number of components can be further reduced, and the size and cost of the device can be further reduced.

In the image forming apparatus according to the sixth aspect,
Even in a color image forming apparatus, the above-described control is performed, so that the toner which is not frequently used can be maintained so that good flight control can always be performed on the carrier, so that desired color reproduction can be always performed and image deterioration does not occur. A color image forming apparatus can be realized.

In the image forming apparatus according to the seventh aspect,
Since the ON potential is relatively negligible with respect to the AC potential applied to the carrier, toner control is not affected by the AC component.

In the image forming apparatus according to the eighth aspect,
Since the oscillating electric field is not formed only in the region facing the gate where toner flying is required, the effect of the oscillating electric field can be maximized.

In the image forming apparatus according to the ninth aspect,
Since the mechanical vibration using PZT is used as the above-mentioned vibration, the potential to be used is low, and the cost increase of the power supply is minimized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a printer having a printing unit according to an embodiment of the present invention.

FIG. 2 is a main part diagram of the image forming apparatus according to the embodiment of the present invention;

FIG. 3 is a diagram of a control electrode of the image forming apparatus according to the embodiment of the present invention;

FIG. 4 is a schematic flowchart showing a printing operation according to an embodiment of the present invention.

FIG. 5 is a pulse waveform chart of an ON potential according to an embodiment of the present invention.

FIG. 6 is a configuration diagram of a color image forming apparatus according to an embodiment of the present invention.

FIG. 7 is an inappropriate pulse waveform chart in one embodiment of the present invention.

FIG. 8 is a diagram of a control electrode according to another embodiment of the present invention.

FIG. 9 is a diagram of a control electrode according to another embodiment of the present invention.

FIG. 10 is an explanatory diagram illustrating potential control in a control electrode according to another embodiment of the present invention.

FIG. 11 is a diagram of a control electrode according to another embodiment of the present invention.

FIG. 12 is an explanatory diagram illustrating potential control in a control electrode according to another embodiment of the present invention.

FIG. 13 is an explanatory diagram illustrating potential control in a control electrode according to another embodiment of the present invention.

FIG. 14 is an explanatory diagram illustrating potential control in a control electrode according to another embodiment of the present invention.

FIG. 15 is an explanatory diagram illustrating potential control in a control electrode according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming part 2 Toner supply part 5 Paper 8 Charging brush 12 Heating roller 14 Pressure roller 17 Static elimination power supply 18 Charging power supply 20 Toner storage tank 21 Toner 22 Toner carrier 23 Doctor blade 24 Dielectric belt 25 Counter electrode 26 Control electrode 27 Ring electrode 27a Strip electrode 27b Strip electrode 28 Static elimination brush 29 Gate 30 High voltage power supply 31 Control power supply unit

Claims (9)

[Claims] 1. A supply means having a carrier for carrying a developer of at least one color, a counter electrode arranged opposite to the carrier, and an insulating member arranged between the carrier and the counter electrode. A substrate, a plurality of gates provided on the insulating substrate and serving as a passage portion of the developer, and at least one or more electrode groups provided around the plurality of gates, a control electrode including: At least a control circuit comprising control circuit means capable of applying a predetermined potential corresponding to at least image data to the individual electrodes of the control electrodes, wherein the control means controls a predetermined potential to a corresponding electrode of the electrode group. Controlling the passage of the developer through the gate to form an image on the surface of the recording medium conveyed between the control electrode and the counter electrode, wherein the control circuit means Game Maintaining the adhesive force between the developer agents carried on the carrier or the adhesive force between the carrier and the developer only at the time of application of a potential at which the passage of the developer can be given or An image forming apparatus, wherein the adhesive force is weakened, or an external force is applied to the developer so that the adhesive force is maintained in a desired controllable range. 2. The image forming apparatus according to claim 1, wherein said developer carried by said carrier vibrates due to said external force. 3. The image forming apparatus according to claim 1, wherein the external force is an electric force having a frequency component, and it is difficult for the external force to move the developer to the recording medium. 4. A supply means having a carrier for carrying a developer of at least one color, a counter electrode disposed opposite to the carrier, and a high electrode for generating a potential difference between the carrier and the counter electrode. High-voltage power supply means for supplying a voltage, an insulating substrate disposed between the carrier and the counter electrode, and a plurality of gates serving as a developer passage portion provided on the insulating substrate, A control electrode composed of at least two or more electrode groups including a first electrode group composed of one or more electrodes and a second electrode group around the plurality of gates, and the first electrode group and the second electrode group Control means comprising control circuit means for supplying a predetermined potential state to the electrodes, a recording medium conveyed between the control electrode and the counter electrode, and the control circuit means for the first and second electrode groups. Apply a predetermined potential according to the image data to the corresponding electrode, and observe In an image forming apparatus for controlling the passage of an image agent through the gate to form an image on the surface of an upper recording medium, the control unit may be configured to control the electrode group more than the electrode group facing the carrier or the electrode group facing the counter electrode. The potential applied to the electrode group facing the carrier arranged so as to reduce the number is controlled such that the external force can be applied to the developer carried on the carrier. Image forming device. 5. A supply means having a carrier for carrying a developer of at least one color, a counter electrode arranged opposite to the carrier, and an insulating member arranged between the carrier and the counter electrode. A substrate, a plurality of gates provided on the insulating substrate and serving as a passage portion of a developer, at least one or more electrode groups provided around the plurality of gates, at least the gate and the gate A shield electrode comprising an electrode having an opening provided so that at least a part of each electrode of the electrode group provided directly or electrically is exposed to the carrier. At least a control means comprising control electrodes arranged between the control electrodes and control circuit means capable of applying a predetermined potential corresponding to at least image data to the individual electrodes of the control electrodes. Flock of In an image forming apparatus that controls the passage of a developer through the gate by applying a predetermined potential to a corresponding electrode to form an image on the surface of a recording medium conveyed between the control electrode and the counter electrode The control electrode includes an electrode group facing the carrier, or the electrode group facing the carrier, which is arranged so that the number of electrodes is smaller than that of the electrode group facing the counter electrode. An image forming apparatus, wherein an electric potential applied to an electrode is controlled so that the external force can be applied to a developer carried on the carrier. 6. A supply means having a carrier for carrying at least a plurality of color developing agents, a counter electrode arranged opposite to the carrier, and an insulating member arranged between the carrier and the counter electrode. A control electrode including at least a conductive substrate, a plurality of gates provided on the insulating substrate and serving as a passage portion of a developer, and at least one or more electrode groups provided around the plurality of gates. And control circuit means that can apply at least a predetermined potential according to image data to each of the control electrodes, and the control means controls a predetermined electrode to a corresponding one of the electrode groups. An image forming apparatus for controlling the passage of the developer through the gate by applying a potential of the control electrode to form a color image on the surface of the recording medium conveyed between the control electrode and the counter electrode; The pole includes the electrode group facing the carrier, or the electrode group facing the carrier, which is arranged so that the number of electrodes is smaller than that of the electrode group facing the counter electrode. The external force is applied to the electrode group facing the carrier, or the potential applied to the electrode group facing the carrier arranged so that the number of electrodes is smaller than that of the electrode group facing the counter electrode. An image forming apparatus, wherein the control is performed so that the developer can be applied to the developer carried on the image forming apparatus. 7. The carrier is supplied with a potential having the frequency component to the carrier, and at least the control unit supplies the developer passing through the gate to the developer carried on the carrier. Is switched to a potential that eliminates a phase difference and a frequency difference between the potential of the electrode group and the potential of the electrode group so that the desired carrier can be controlled, or the potential of the electrode group is a DC potential and the DC potential Has a switching means for switching the potential so as to apply a DC potential as the potential of the carrier when the voltage is applied to the electrode group, and by performing the switching, the external force is applied to the developer. An image forming apparatus comprising: 8. The potential applied to the electrode group as a potential for supplying the potential having the frequency component to the carrier and simultaneously causing the control means to pass the gate to the developer carried on the carrier. An image forming apparatus, wherein the external force is applied to the developer by applying a potential having at least the same or substantially the same frequency component as the potential having the frequency component. 9. An image forming apparatus according to claim 1, wherein said external force is mechanical minute vibration, and said control is performed on said minute vibration.