JPH09240033A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the length of a control electrode and eliminate a difference in the intensity of an electric field applied to a part opposed to the center part of a control electrode and the intensity of an electric field applied to a part opposed to the end part by forming groups, each of which consists of electrodes between a carrier and an opposed electrode and forming an image under the selective control of the scattering of a charged image visualizing particle based on a potential to be applied. SOLUTION: Line electrodes and column electrodes form a 4×640 matrix electrode, and eight pieces of the line electrode 30a-30d, 31a-31d are split into two groups, each of which consists of four line electrodes. These groups are controlled respectively by a means 29f for switching a voltage for eight channels. On the other hand, two groups of the column electrodes, each of which consists of 320 column electrodes, and five pieces of a means for switching a voltage 29a-29e for 64 channels control the two groups of the column electrodes. Consequently, the number of the means for switching a voltage can be reduced by splitting the electrodes into groups each of which is placed under control. Therefore, the length of a control electrode does not change and all the non-conformity caused by the long size of the control electrode 19 can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a printing section of a digital copying machine and a facsimile machine, a digital printer, a plotter, etc., and forms an image on a recording medium by flying visible particles. It relates 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, the toner image forming particles are directly attached to the recording medium to form a toner image on the recording medium. An image forming apparatus that directly forms on a recording medium has been proposed (for example, Japanese Patent Laid-Open No. 6-155798). The conventional image forming apparatus will be described below with reference to FIG.

As shown in FIG. 4, the above-mentioned conventional image forming apparatus is provided with an image forming section 53 having a toner supply section 51 and a printing section 52, and causes a toner 54 to fly and a sheet 55 as a recording medium. And the toner 54
An image is directly formed on the sheet 55 by controlling the flight of the sheet based on the image signal.

The toner supply section 51 contains a toner containing box 5 containing a toner 54 as negatively charged developing particles.
6 and a toner carrier 57 that carries the toner 54 by magnetic force. The toner carrier 57 is grounded, and the surface speed is 30 mm / se in the direction of the arrow in the figure.
Rotate with c. The toner 54 is a magnetic toner having an average particle size of 10 μm and has a charge amount of −4 μC according to a known technique.
The electric charge is applied so as to be / g to −5 μC / g. The toner 54 is carried on the outer peripheral surface of the toner carrier 57 with an average thickness of 80 μm.

The printing section 52 of the image forming section 53 has a diameter of 50.
It is provided with a counter electrode 58 made of a mm aluminum tube and a control electrode 59 provided between the counter electrode 58 and the toner carrier 57. The counter electrode 58 is provided so that the distance from the outer peripheral surface of the toner carrier 57 is 1 mm. The counter electrode 58 is applied with a high voltage of 2 kV by the DC power supply unit 60, and in the figure, the toner carrier 57 has a surface velocity of 30 mm / sec in the direction of the arrow.
Rotates at the same peripheral speed as. That is, an electric field required to cause the toner 54 carried on the toner carrier 57 to fly toward the counter electrode 58 is applied between the counter electrode 58 and the toner carrier 57.

The control electrode 59 is parallel to the tangential direction of the surface of the counter electrode 58 and is two-dimensionally spread so as to face the counter electrode 58, and the toner from the toner carrier 57 to the counter electrode 58 is formed. It has a structure that allows flow. The electric potential supplied to the control electrode 59 changes the electric field applied between the toner carrier 57 and the counter electrode 58 to control the flight of the toner 54 from the toner carrier 57 to the counter electrode 58. It

The control electrode 59 is the toner carrier 57.
Is provided so that the distance from the outer peripheral surface thereof is 100 μm. The control electrode 58 includes a flexible printed circuit board (FPC) 59a having a thickness of 50 μm as shown in FIG.
A strip electrode 61 (row electrode 61) made of a copper foil having a thickness of 20 μm
a and the column electrode 61b). Substrate 5
A gate 62 having a diameter of 150 μm, which serves as a passage portion for the toner 54, is formed on 9a, and the above-mentioned strip electrode 61 is provided around these gates 62. Each of the strip electrodes 61 is electrically connected to the control power supply unit 63 via a power supply line and a high voltage driver.

The control power supply unit 63 (FIG. 4) applies a potential of 150 V which allows the toner 54 to pass through the gate 62 to a strip potential 61.
To the belt-shaped electrode 61, a first power source 64 for supplying the toner 54 with a potential of −200 V to the belt-shaped electrode 61, a pull-up resistor 66, a FET 67 as a voltage switching means, and an image signal control. It comprises a circuit 68. Normally, the FET 67 is turned on by the image signal control circuit 68.
In the N state, a potential that does not allow the toner 54 to pass through the gate 62 is applied to the strip electrode 61. When the FET 67 is turned off by the image signal control circuit 68, the toner 5
The strip electrode 61 is provided with an electric potential that allows 4 to pass through the gate 62. By the control power supply unit 63, the strip electrode 61 is
A voltage according to the image signal is applied. That is, the control power supply unit 63 applies 150 V to the belt-shaped electrode 61 for 300 μsec when the toner 54 carried by the toner carrying pair 57 is passed in the direction of the counter electrode 58, and is -200 V when it is not passed. Is applied. In this way, when the potential applied to the control electrode 59 is controlled according to the image signal and the paper 55 is placed on the surface of the counter electrode 58 facing the toner carrier 57, the surface of the paper 55 responds to the image signal. The toner image is directly formed.

The rotation of the toner carrier 57, the rotation of the counter electrode 58, the application of a potential that does not allow the toner 54 to pass through to the control electrode 59, and the application of the high voltage to the counter electrode 58 are applied almost simultaneously by a single trigger. To be done.

[0010]

In the above-mentioned conventional image forming apparatus, since matrix control of the control electrode 58 is used, a transistor for switching the potential or a voltage switching is possible as compared with the case where the gate 62 is single driven by one electrode. There is an advantage that the number of means is significantly reduced. How much the number of voltage switching means can be reduced depends on the number of gates arranged in the column electrode (61b in FIG. 6) extending in the length direction of the control electrode. The larger the number of gates arranged on one strip electrode, the smaller the number of voltage switching means to be reduced. For example, in the case of a single drive, if A4 is 300 DPI, the required number of transistors is 2560, but in the matrix drive of 4 × 640 as in the prior art, the number is 644. 8x32 this
With a matrix drive of 0, the number of transistors can be reduced to 328, which is about half.

However, when the 8 × 320 matrix is changed from the conventional 4 × 640 matrix, the control electrode 5
The length of 8 (L in FIG. 6) becomes longer. When the length of the control electrode 58 becomes long, the distance between the central portion and the end portion of the control electrode 58 in the L direction changes with the toner carrier 57, and the length becomes short at the central portion and becomes long at the end portion.

Therefore, when the length of the control electrode 59 increases, the distance between the toner carrier 57 and the control electrode 59 differs between the central portion and the end portion. In this case, the electric field felt by the toner 54 on the surface of the toner carrier 57 has a large difference between the portion facing the central portion and the portion facing the end portion of the control electrode 59.

For example, the electric field in the portion facing the central portion of the control electrode 59 and the electric field in the portion facing the end portion weaken the electric field in the portion facing the end portion, so that flight control of the toner 54 becomes difficult. In some cases, flight control becomes impossible in the worst case.

In order to avoid this, until now, there have been roughly divided two types. One is to change the electric potential applied to the electrode at the central portion and the end portion, and the second is to change the toner carrier 57.
That is, flatten the portion facing the control electrode 59.

When the potential applied to the control electrode 59 is changed between the end portion and the central portion, it is easy to think that the number of power sources increases, but the withstand voltage of other voltage switching means used further increases, and at the same time, the insulation between electrodes is increased. Must also be higher. Therefore, an increase in the number of parts and an increase in cost cannot be avoided. In order to flatten the surface of the toner carrier 57 facing the control electrode 59, it is easy to form the toner carrier 57 with a belt, but in this case as well, it is difficult to control the layer thickness and charge amount of the toner 54. Toner with belt 54
Is technically more difficult than the case where the above sleeve is used, and there is an inherent problem that the distance between the control electrode 59 and the control electrode 59 becomes unstable due to the bending of the belt. Increasing size and increasing costs are unavoidable.

That is, although both of the above two measures easily lead to new problems and increase in cost, the central portion and the end portion of the strength of the electric field acting on the toner 54 on the surface of the toner carrier 57. And the potential required for controlling the flight of the toner 54 at the end portion becomes large. Therefore, the number of power sources used increases and the breakdown voltage of the transistors used increases further. Therefore, the number of parts and the cost are increased.

The use of a belt member as the toner carrier 57 has been studied as a measure for avoiding a problem relating to the flight control of the toner 54 due to the length of the control electrode 58 becoming longer.

Even if a belt member is used, if the length of the control electrode 58 becomes long, the portion for maintaining the parallelism becomes long and the influence of the bending and wrinkling of the belt easily occurs, which is not desirable. Furthermore, if a belt is used, an increase in the number of parts, an increase in the size of the device, and an increase in cost cannot be avoided.

Further, when a color image forming apparatus is formed, a plurality of control electrodes 58 are usually used. Again,
When the form of matrix control is changed in order to reduce the number of transistors used, the length of the electrode becomes long as described above. Compared with the case of black and white, this degree is
The number of colors of the toner 54 simply used is increased. Therefore, in the case of color, the above-mentioned problems become more remarkable.

[0020]

In order to solve the above-mentioned problems, the image forming apparatus of the present invention according to claim 1 is provided with a carrier for supporting the image-forming particles, and is arranged to face the carrier. A counter electrode, a control electrode having a plurality of gates, which are disposed between the carrier and the counter electrode, and serve as a passage portion for visualization particles, and the control electrode is provided between the carrier and the counter electrode. And a plurality of openings and electrodes provided around each of the openings, respectively, and recording of the visualized particles through the openings corresponding to each other based on the potential applied to the electrodes. The first and second control electrode groups for selectively controlling the flight to the medium, respectively, and applying the predetermined potential to the corresponding electrodes of the first and second control electrode groups, the gate of the visualized particles. An image forming apparatus including a control unit that controls the passage of a sheet and forms an image. Te, the first control electrode group and the second control electrode group has a plurality form a group comprising a plurality of electrodes.

The image forming apparatus of the present invention according to claim 2 is
The control means has a voltage switching means for switching the potential applied to the electrodes of the first and second control electrode groups inside, and each group of either one of the first and second control electrode groups is The voltage switching means is shared.

The image forming apparatus of the present invention according to claim 3 is
The number of electrode groups that do not share the voltage switching means is equal to or larger than the number of groups of the electrode groups that share the voltage switching means.

According to the above structure, the number of transistors to be used can be reduced without changing the length of the control electrode composed of the first and second control electrode groups, and the length of the control electrode does not change, so that the toner carrying member is not changed. Since the distance between the control electrode and the control electrode does not change from before the transistor reduction, and the physical elements required for the transistor flight control do not change at all, it is not necessary to adjust the physical amount of the toner flight control due to the transistor reduction.
The number of parts for adjusting the physical quantity does not increase.

The image forming apparatus of the present invention according to claim 4 is
A plurality of the above-mentioned carriers are provided so as to carry a plurality of color-visualizing particles, and the control means is a single electrode in any one of the first and second control electrode groups. The same potential can be applied from one terminal.

According to the above structure, even in the color image forming apparatus, a plurality of the above-mentioned carriers are provided so as to carry a plurality of color-visualizing particles, and the above-mentioned control means is the above-mentioned first and second control electrode groups. It is possible to apply the same potential from a single terminal to any one electrode in each of the groups.

The image forming apparatus of the present invention according to claim 5 is
A carrier for supporting the visualized particles, a counter electrode arranged to face the carrier, and a plurality of gates, which are disposed between the carrier and the counter electrode and serve as passage portions for the visualized particles, are provided. The control electrode having and the control electrode are provided in order between the carrier and the counter electrode, each of which is provided with a plurality of openings and an electrode provided around each opening, and is applied to the electrode. A first and a second control electrode group for selectively controlling the flight of the charged visualized particles to the recording medium through the corresponding openings based on the electric potential. An image forming apparatus, comprising: a control unit that applies a predetermined potential to corresponding electrodes of the group to control passage of the visualized particles through the gate to form an image, and the control unit has the first internal unit. Voltage switching for switching the potential applied to the electrodes of the first and second control electrode groups Each of the first and second control electrode groups has a step, and each electrode group of the first and second control electrode groups forms two groups of a plurality of electrodes. Control means for applying the same potential from a single terminal to any one of the electrodes is provided.

According to the above structure, the number of transistors to be used can be reduced without changing the length of the control electrode composed of the first and second control electrode groups, and the length of the control electrode does not change, so that the toner carrier can be carried. Since the distance between the control electrode and the control electrode does not change from before the transistor reduction, and the physical elements required for the transistor flight control do not change at all, it is not necessary to adjust the physical amount of the toner flight control due to the transistor reduction.
The number of parts for adjusting the physical quantity does not increase, and the arrangement of the feeder line for applying a potential from the same transistor to the electrode group is the simplest, and the feeder line is arranged between the first and second control electrode groups. Therefore, the structure of the control electrode can be simplified and voltage leakage between the electrodes can be prevented.

The image forming apparatus of the present invention according to claim 6 is
A plurality of the above-mentioned carriers are provided so as to carry a plurality of color-visualizing particles.

According to the above arrangement, even in a color image forming apparatus, the number of transistors used can be reduced without changing the length of the control electrode composed of the first and second control electrode groups, and the length of the control electrode can be reduced. Since the distance does not change, the distance between the toner carrier and the control electrode does not change from that before transistor reduction, and the physical elements necessary for transistor flight control do not change at all, so it is possible to adjust the physical amount of toner flight control accompanying transistor reduction. It is not necessary at all, the number of parts for adjusting the physical quantity does not increase, and the arrangement of the power supply line for applying a potential from the same transistor to the electrode group is the simplest and is between the first and second control electrode groups. It is possible to simplify the structure of the control electrode without arranging a power supply line at the electrode and prevent voltage leakage between the electrodes.

[0030]

FIG. 1 shows an embodiment of the present invention.
The following is a description based on FIGS.
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.

The outline of each element of the image forming apparatus according to the present embodiment will be described.

As shown in FIG. 1, the image forming apparatus of the present embodiment includes an image forming section 3 having a toner supply section 1 and an application section 2. The image forming section 3 visualizes an image corresponding to an image signal on a sheet 5 which is a recording medium by using the toner 4 as the visualized particles. That is, the image forming apparatus directly forms an image on the paper 5 by causing the toner 4 to fly and adhere to the paper 5 and controlling the flight of the toner 4 based on an image signal.

A paper feeding device 6 is provided on the paper input side of the paper 5 into the image forming section 3. The paper feeding device 6 is composed of a paper cassette 7 for accommodating the paper 5 as a recording medium, a pickup roller 8 for feeding the paper 5 from the paper cassette 7, and a paper feed guide 9 for guiding the supplied paper 5. Further, the paper feeding device 6 includes a paper feeding sensor (not shown) that detects that the paper 5 has been fed. The pickup roller 8 is rotationally driven by a driving device (not shown).

A fixing unit 10 for fixing the toner image formed on the paper 5 in the image forming unit 3 to the paper 5 by heating and pressurizing the toner image formed on the paper 5 from the image forming unit 3 is provided. Is provided. The fixing unit 10 includes a heating roller 11, a heater 12, a pressure roller 13, a temperature sensor 14,
And a temperature control circuit 15.

The heating roller 11 is made of, for example, an aluminum tube having a thickness of 2 mm. The heater 13 is composed of, for example, a halogen lamp and is built in the heating roller 11. The pressure roller 13 is made of, for example, silicone resin. Then, for example, a load of 2 kg is applied to the heating roller 11 and the pressure roller 13 provided so as to face each other so that the paper 5 can be sandwiched and pressed by springs or the like (not shown) at both ends of each shaft. Has been added.
The temperature sensor 14 measures the temperature of the surface of the heating roller 11. The temperature control circuit 15 is controlled by a main controller (described later), controls ON / OFF of the heater 12 based on the measurement result of the temperature sensor 14, and the heating roller 1
1 The temperature of the surface is maintained at 150 ° C, for example.

The fixing unit 10 also includes a paper discharge sensor (not shown) for detecting that the paper 5 has been discharged.

The materials of the heating roller 11, the heater 12, the pressure roller 13 and the like are not particularly limited. Moreover, the temperature of the surface of the heating roller 11 is not particularly limited. Further, the fixing unit 10 may be configured to fix the toner image by heating or pressing the paper 5.

Although not shown, on the side of the paper output from the fixing unit 10, there are a paper discharge roller for discharging the paper 5 processed by the fixing unit 10 onto a paper discharge tray, and the discharged paper 5. A receiving tray for receiving is provided. The heating roller 11, the pressure roller 13, and the paper discharge roller described above are rotationally driven by a driving device (not shown).

The toner supply unit 1 of the image forming unit 3 includes a toner storage tank 1 in which the toner 4 as the image-forming particles is stored.
6, a toner carrier 17 as a cylindrical carrier (sleeve) for carrying the toner 4 by a magnetic force, and a toner storage tank 16 are provided inside to charge the toner 4 and the outer periphery of the toner carrier 17. The doctor blade 18 regulates the thickness of the toner layer carried on the surface. The doctor blade 18 is provided on the upstream side in the rotation direction of the toner carrier 17 so that the distance from the outer peripheral surface of the toner carrier 17 is, for example, 60 μm. The toner 4 is, for example, a magnetic toner having an average particle size of 6 μm, and the doctor blade 18 causes a charge amount of −4 μC /
The charge is applied so as to be g to -5 [mu] C / g.
The distance between the doctor blade 18 and the toner carrier 17 is not particularly limited. Further, the average particle diameter and the charge amount of the toner 4 are not particularly limited.

The toner carrier 17 is driven by a driving device (not shown) and rotates in the direction of arrow A at a speed of 100 mm / sec on the surface thereof, for example. Further, the toner carrier 17 is grounded, and at a position facing the doctor blade 18 inside the toner carrier 17, and
A magnet (not shown) is arranged at a position facing a control electrode 19 (described later). As a result, the toner carrier 1
The toner 7 can carry the toner 4 on its outer peripheral surface. Further, the toner 4 carried on the outer peripheral surface of the toner carrier 17 forms so-called spikes at a position corresponding to the above position on the outer peripheral surface.

The rotation speed of the toner carrier 17 is not particularly limited. Further, the toner carrier 17 is
Instead of carrying the toner 4 by a magnetic force, the toner 4 may be carried by an electric force, or an electric force and a magnetic force.

The printing unit 2 of the visible image forming unit 3 has, for example, a thickness of 1
a counter electrode 20 which is made of an aluminum plate of mm and faces the outer peripheral surface of the toner carrier 17, a high-voltage power supply 21 for supplying a high voltage to the counter electrode 20, and a control electrode provided between the toner carrier 17. 19, a static elimination brush 22, a static elimination power source 23 for giving a static elimination potential to the static elimination brush 22, a charging brush 24 for charging the paper 5, a driving means (not shown) for driving the charging brush 24, and a charging brush 24 A charging power source 25 for applying a charging potential, a dielectric belt 26, support members 27a and 27b for supporting the dielectric belt 26, and a cleaner blade 28 are provided.

The counter electrode 20 is provided so that the distance from the outer peripheral surface of the toner carrier 17 is, for example, 1 mm. The dielectric belt 26 is made of PVDF as a base material and has a volume resistivity of 10 ¹⁴ Ω · cm and a thickness of 75 μm. The dielectric belt 26 is driven by a driving device (not shown), and the speed on the surface thereof is, for example, 30 mm in the direction of the arrow in the figure.
Rotate at / sec. A high voltage of, for example, 2.3 kV is applied to the counter electrode 20 by a high voltage power supply unit (control means) 21. That is, an electric field required to cause the toner 4 carried on the toner carrier 17 to fly toward the counter electrode 20 between the counter electrode 20 and the toner carrier 17 due to the high voltage applied from the high voltage power supply unit 21. Is given.

The charging brush 24 is made of foamed rubber having urethane as a base material and has characteristics of hardness of JIS-A 30 ° and resistance value of 10 ⁸ Ω · cm.

The static elimination brush 22 is provided on the downstream side of the control electrode 19 in the rotating direction of the dielectric belt 26 so as to be in pressure contact with the dielectric belt 26. A static elimination power source 23 applies a static elimination potential of 2.5 kV to the static elimination brush 22 to eliminate unnecessary electric charges existing on the surface of the dielectric belt 26.

The cleaning blade 28 described above removes the toner 4 when the toner 4 adheres to the surface of the counter electrode 20 due to an unexpected situation such as paper jam (paper jam) and the like, and the back surface of the paper 5 is removed. Are prevented from being contaminated by the toner 4. The material of the counter electrode 20 is not particularly limited. In addition, the counter electrode 20
The distance between the toner carrier 17 and the toner carrier 17 is not particularly limited. Furthermore, the rotation speed of the counter electrode 20 and the applied voltage are not particularly limited.

Although not shown, the image forming apparatus is
As a control circuit, a main control unit that controls the entire image forming apparatus, an image processing unit that converts image data obtained from an image reading device that reads an image of a document or the like into a format of image data to be printed, An image memory for storing the image data and an image formation control unit for converting the image data obtained from the image processing unit into the image data to be given to the control electrode 19 are provided.

The control electrode 19 is parallel to the tangential direction of the surface of the counter electrode 20 and faces the counter electrode 20.
It is dimensionally spread and has a structure in which the toner flow from the toner carrier 17 toward the counter electrode 20 can pass.
The electric field supplied to the toner 4 on the surface of the toner carrier 17 is changed by the potential supplied to the control electrode 19, and the flight of the toner 4 from the toner carrier 17 to the counter electrode 20 is controlled.

The control electrode 19 is the toner carrier 17
Is provided so that the distance from the outer peripheral surface thereof is, for example, 100 μm, and is fixed by a support member (not shown). As shown in FIG. 2, the control electrode 19 includes an insulating substrate 19a, voltage switching means 29a to 29f, and independent strip conductors, that is, strip electrodes 30, 31, and 3.
It consists of 2, 33. The substrate 19a is made of, for example, a polyimide resin and has a thickness of 25 μm. In addition, the substrate 19a is formed with a hole to be a gate 34 described later. The strip electrodes 30 to 33 are made of, for example, a copper foil, are provided on the surface of the substrate 19a on the side of the toner carrier 17 and the side of the counter electrode 20, that is, around the holes, and are arranged according to a predetermined arrangement. Each strip electrode 3
0 to 33 are formed with a diameter of 220 μm and a thickness of 30 μm, for example. The opening of each strip electrode 29 is formed to have a diameter of 200 μm, for example, and the toner carrier 17
It is a passage portion for the toner 4 flying from the counter electrode 20 to the counter electrode 20. Hereinafter, this passage will be referred to as the gate 34. The distance between the control electrode 19 and the toner carrier 17 is
There is no particular limitation. Further, the size of the gate 34, the material and the thickness of the substrate 19a and the strip electrodes 30 to 33 are not particularly limited.

The gate 34, that is, the strip electrodes 30 to.
The number 33 of, for example, 2560 is formed, and each of the strip electrodes 30 to 33 has a voltage switching means 29a of 64 channels of a control power supply unit 36 (described later) via a power supply line 35.
It is electrically connected to 29f.

The above number corresponds to a resolution of 300 DPI (dot per inch) in the width of A4 size paper. still,
The number of the strip electrodes 30 to 33 is not particularly limited.

The surfaces of the strip electrodes 30 to 33 and the surface of the power supply line 35 are covered with an insulating layer (not shown) having a thickness of 30 μm, whereby the strip electrodes 30 to 33 are formed.
The insulation between them, the insulation between the power supply lines 35, and the insulation between the strip-shaped electrodes 30 to 33 that are not connected to each other and the power supply line 35 are ensured. The material and thickness of the insulator layer are not particularly limited.

The strip electrodes 30 to 33 of the control electrode 19 include:
A pulse corresponding to the image signal, that is, a voltage is applied by the control power supply unit (control means) 36. That is, the control power supply unit 3
6 is applied to the belt-shaped electrode 30 when the toner 4 carried on the toner carrier 17 is passed in the direction of the counter electrode 20, for example, 150 V is applied, and when it is not passed, for example, −
A voltage of 200 V is applied.

As described above, when the potential applied to the control electrode 19 is controlled according to the image signal and the paper 5 is arranged on the surface of the counter electrode 20 facing the toner carrier 17, the image signal is printed on the surface of the paper 5. A toner image corresponding to is formed. The control power supply unit 36 is controlled by a control electrode control signal sent from an image forming control unit (not shown).

Next, the image forming operation of the image forming apparatus will be described with reference to 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 receiving this input starts the 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, and stored in the image memory. The image data stored in the image memory is transferred to the image forming control unit, and the image forming control unit starts converting the input image data into a control electrode control signal to be given to the control electrode 19.

Further, when the image forming control unit receives a predetermined amount of the control electrode control signal, a driving device (not shown) is actuated, and the pickup roller 8 shown in FIG. The paper 5 in 7 is sent out toward the image forming unit 3, and a normal paper feed state is detected by a paper feed sensor. The sheet 5 sent out by the pickup roller 8 is the charging brush 2
4 and the support members 27a and 27b. The supporting electrodes 27a and 27b are connected to the counter electrode 2 by the high voltage power source 21.
The same potential as 0 is applied. The charging brush 24 has a charging electrode 2
As a charging potential, 1.2 kV is applied by 5. The sheet 5 is supplied with an electric charge due to the potential difference between the charging brush 24 and the supporting members 27a and 27b, and is electrostatically adsorbed on the surface of the dielectric belt 26 of the printing unit 2 of the image forming unit 3 facing the toner carrier 17. Be transported. The predetermined amount of the control electrode control signal varies depending on the configuration of the image forming apparatus.

After that, the image forming control unit supplies the control electrode control signal to the control power supply section 36. The supply of the control electrode control signal is performed at a timing synchronized with the supply of the sheet 5 to the printing unit 2 by the charging brush 24. The control power supply unit 36 controls the high voltage applied to each of the strip electrodes 30 to 33 of the control electrode 19 based on the control electrode control signal. That is, the control power supply unit 36 appropriately applies a voltage of 150 V or −200 V to the predetermined strip electrode 30 to control the electric field near the control electrode 19. That is, at the gate 34 of the control electrode 19, the toner 4 from the toner carrier 17 to the counter electrode 20 is transferred in accordance with the image data.
Is stopped and released as appropriate. As a result, the rotation of the counter electrode 20 causes 30
A toner image corresponding to the image signal is formed on the sheet 5 moving at a speed of mm / sec.

The sheet 5 on which the toner image is formed is the supporting member 2
The toner image is fixed on the paper 5 by the fixing unit 10 after being peeled off from the dielectric belt 26 and conveyed to the fixing unit 10 at the extreme ratio of 7b. Paper 5 with the toner image 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 determines a normal end of the printing operation.

By the image forming operation described above, a good image is formed on the sheet 5. In the present image forming apparatus, an image is formed directly on the sheet 5, and therefore, a visualized body such as a photoconductor and a dielectric drum used in a conventional image forming apparatus is not required.

Therefore, the transfer operation for transferring the image from the image developer to the sheet 5 is omitted, so that the image is not deteriorated.
For this reason, the reliability of the device is improved. Further, since the structure of the device is simplified and the number of parts is reduced, it is possible to reduce the size and cost.

As described above, the toner carrier 17 is grounded, while the counter electrode 20 and the supporting member 27a are applied with a high voltage of 2.3 kV, and the charging brush 24 is applied with a high voltage of 1.2 kV. Therefore, due to the potential difference between the charging brush 24 and the support member 27 a, a negative charge is supplied to the surface of the sheet 5 conveyed between the charging brush 24 and the dielectric belt 26. When the negative charge is supplied, the electrostatic force of the charge causes the sheet 5 to be attracted to the dielectric belt 26, and the dielectric belt 26 moves to cause the gate 34 to move.
Move directly under. The electric charges on the surface of the dielectric belt 26 are attenuated in time until they reach the position directly below the gate 34, and the counter electrode 2
The surface potential is 2 kV in consideration of the potential of 0.

In this state, in order to allow the toner 4 carried on the toner carrier 17 to pass in the direction of the counter electrode 20, the control power supply unit 35 causes the strip electrodes 30 to 33 of the control electrode 19.
If a voltage of 150 V is applied to each pixel for 150 μsec and the toner 4 does not pass through the gate 34, −2
A potential of 00V is applied. In this way, the sheet 5 is directly formed on the surface of the sheet 5 while being attracted to the dielectric belt 26.

In the above description, the potential applied to the belt-shaped electrodes 30 to 33 of the control electrode 19 to pass the toner 4 is 150 V, but the potential is desired by the toner 4. If flight control can be performed, it is not particularly limited. Similarly, the potential applied to the counter electrode 20, the potential applied to the charging brush 24, and the surface potential of the paper 5 immediately below the gate 34 are not particularly limited as long as the desired flight control of the toner 4 can be performed.

In the above embodiment, the degree of bulging of the equipotential surface near the gate 34 of the control electrode 19 can be changed by changing the potential applied to the strip electrodes 30, 31 of the control electrode 19. That is, gate 3
It is possible to change the electric force acting on the toner 4 passing through the toner 4. Therefore, the dot diameter of the image formed on the paper 5 can be arbitrarily adjusted by appropriately changing the potential applied by the control power supply unit 35. The potential applied to the strip electrodes 30 to 33 of the control electrode 19 to prevent passage of the toner 4 is not particularly limited.

The matrix electrode used as the control electrode 19 in this embodiment will be further described.

.., 31a .. and column electrodes 32a .., 33a are provided as shown in FIG. Row electrode 3
0, 31 and column electrodes 32, 33 constitute a 4 × 640 matrix electrode. Row electrodes 30a to 30d, 31a
8 to 31d form a group of four as shown in FIG. 2 and are controlled by the voltage switching means 29f of eight channels, respectively. The column electrodes 32 and 33 form a group of 320 lines each, and are controlled by five voltage switching units 29a to 29e of 64 channels.

Specifically, for example, when the gates 34 (1) and 34 (320) in FIG. 2 are ON and the other gates 34 are OFF, the following control is performed.

First, the voltage switching means 29f turns on the row electrode 30a, the other row electrodes 30b to 30d and the row electrodes 31a to 31d are turned off, and the voltage switching means 29a turns on the column electrodes 32a and 33a and the column electrode 32b.
To 32 (320) and column electrodes 33b to 33 (320) are O.
The gate 34 is FF, and the matrix is turned on first.
(1) is printed.

Next, the voltage switching means 29f turns on the row electrode 31a, turns off the other row electrodes 30a to 30d and row electrodes 31b to 31d, turns on the column electrode 33a that has become the column electrode 32a, and turns on the column electrodes 32b to 32. (320) and the column electrodes 33b to 33 (320) are turned off, and the matrix is turned on.
The printed gate 34b is printed.

In this embodiment, the number of transistors required for the 4 × 640 matrix control can be reduced to about half. In the prior art, the number of transistors used in the matrix control of 4 × 640 is 644, but in the present embodiment, the number is 328 as described above, and the number of 64-channel voltage switching means 29 is five, which is half.

Therefore, since the number of voltage switching means to be used is reduced by dividing the electrodes into groups and controlling each group as in the present embodiment, the length of the control electrode 19 changes as described above. Therefore, it is possible to avoid all the problems caused by the lengthening of the control electrode 19.

Further, although the image forming apparatus for monochromatic monochromatic printing is used in the present embodiment, a plurality of toner supplying portions and a plurality of printing portions are provided, and each of the toner supplying portions has a color toner such as yellow and magenta. It is also possible to form a color image forming apparatus using cyan, cyan and black. In such a case, the present embodiment is more effective.

For example, when the present invention is used for the control electrode 19 using the matrix control of 4 × 640, the five voltage switching means can be eliminated for one color as described above, resulting in reduction. The number of voltage switching means is 4
The number is doubled to 20, making it possible to significantly reduce costs.

In the above embodiment, the number of electrode groups is two. Although it is possible in principle to form three or more groups, it is necessary that N ≦ n with respect to the number N of column electrode groups and the number n of row electrode groups.

For example, in the case of n> N, there are two or more electrodes to which a potential is supplied from one transistor in the row electrode corresponding to one column electrode, which makes printing control impossible.

When the number of electrode groups is three or more, for example, when the row electrode of the above embodiment is divided into three groups, it is easy to dispose the power supply lines in the groups at both ends. It is difficult to arrange the power feed lines in the central group. In the central group, it is necessary to arrange the power supply line between the row electrodes, and a finer electrode pattern is required.
However, since the applied potential is a high voltage as described above, current leakage between the electrodes can easily occur, so that the reliability is deteriorated.

According to the present invention, it is not necessary to dispose a power supply line between the row electrodes, the structure of the control electrode can be simplified, and the yield and cost can be reduced.

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

The image forming apparatus according to the present invention is, for example,
The present invention can be suitably applied to a printing section of a digital copying machine and a facsimile machine, a digital printer, a plotter, and the like.

[0081]

Since the image forming apparatus according to the first to third aspects of the present invention has the above-described structure, the transistor used without changing the length of the control electrode composed of the first and second control electrode groups can be used. The number of transistors can be reduced and the length of the control electrode does not change, so the distance between the toner carrier and the control electrode does not change from that before the transistor reduction, and the physical elements necessary for transistor flight control do not change at all. There is no need to adjust the physical quantity of toner flight control,
It is possible to prevent an increase in the number of parts required for adjusting the physical quantity.

An image forming apparatus according to a fourth aspect of the present invention is provided with a plurality of the carriers so as to carry a plurality of color developing particles, and the control means is one of the first and second control electrode groups. The same potential can be applied to any one electrode in each group from a single terminal, and even in a color image forming apparatus, a control electrode composed of the first and second control electrode groups can be applied. The number of transistors used can be reduced without changing the length, and the length of the control electrode does not change, so the distance between the toner carrier and the control electrode does not change from that before the transistor reduction, and it is a physical element necessary for transistor flight control. Does not need to be adjusted at all, so that it is not necessary to adjust the physical quantity of the toner flight control due to the transistor reduction, and it is possible to prevent an increase in the number of parts necessary for adjusting the physical quantity.

In the image forming apparatus according to the fifth aspect, the number of transistors used can be reduced without changing the length of the control electrode consisting of the first and second control electrode groups, and the length of the control electrode does not change. Since the distance between the toner carrier and the control electrode does not change from before the transistor reduction, and the physical elements necessary for transistor flight control do not change at all, there is no need to adjust the physical amount of toner flight control due to the transistor reduction. It is possible to prevent an increase in the number of parts for adjusting the physical quantity. When the number of groups is two, the arrangement of the power supply line for applying a potential from the same transistor to the electrode group is the simplest, and it is necessary to dispose the power supply line between the first and second control electrode groups. Without simplifying the structure of the control electrode, it is possible to reliably prevent voltage leakage between the electrodes,
It is possible to reduce the yield and reduce the cost.

In the image forming apparatus according to the sixth aspect, even in the color image forming apparatus, the number of transistors used can be reduced without changing the length of the control electrode composed of the first and second control electrode groups, and the control can be performed. Since the electrode length does not change, the distance between the toner carrier and the control electrode does not change from before transistor reduction, and the physical elements necessary for transistor flight control do not change at all.Therefore, the physical quantity of toner flight control accompanying transistor reduction does not change. No adjustment is required at all, and an increase in the number of parts for adjusting the physical quantity can be prevented. When the number of groups is two, the arrangement of the power supply line for applying a potential from the same transistor to the electrode group is the simplest, and it is necessary to dispose the power supply line between the first and second control electrode groups. Without this, the structure of the control electrode can be simplified, voltage leakage between the electrodes can be reliably prevented, and the yield and cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a front view showing a configuration of a main part of a control electrode included in the image forming apparatus.

FIG. 3 is an explanatory diagram illustrating an operation at the start of operation of the image forming apparatus.

FIG. 4 is a schematic explanatory diagram illustrating a configuration of a conventional image forming apparatus.

FIG. 5 is an explanatory diagram illustrating a control unit in a conventional image forming apparatus.

FIG. 6 is a front view of control electrodes of a conventional image forming apparatus.

[Explanation of symbols]

 3 Image Forming Section 4 Toner (Visualizing Particles) 5 Paper 17 Toner Carrier (Carrier) 19 Control Electrode 20 Counter Electrode 21 High Voltage Power Supply (Control Means) 29 Strip Electrode 30, 31 Row Electrode 32, 33 Column Electrode 34 Gate 35 Control power supply unit (control means) 36 Image signal control circuit

Claims (6)

[Claims] 1. A carrier for supporting visualized particles, a counter electrode arranged to face the carrier, and a carrier disposed between the carrier and the counter electrode to serve as a passage for the visualized particles. A control electrode having a plurality of gates, the control electrode is provided between the carrier and the counter electrode in order, and a plurality of openings and electrodes provided around the respective openings are provided. The first and second control electrode groups for selectively controlling the flight of the charged visualized particles to the recording medium through the openings corresponding to each other based on the potential applied to the electrodes. And a control unit that applies a predetermined potential to a corresponding electrode of the second control electrode group to control passage of the visualized particles through the gate to form an image. The control electrode group and the second control electrode group form a plurality of groups of a plurality of electrodes. The image forming apparatus characterized by being. 2. The control means internally has voltage switching means for switching the potentials applied to the electrodes of the first and second control electrode groups, wherein either one of the first and second control electrode groups has an electrode. The image forming apparatus according to claim 1, wherein each of the groups shares the voltage switching means. 3. The image forming apparatus according to claim 2, wherein the number of electrode groups that do not share the voltage switching means is equal to or larger than the number of groups of the electrode groups that share the voltage switching means. 4. A plurality of the supporting bodies are provided so as to support a plurality of color image-forming particles, and the control means is any one of the first and second control electrode groups. The image forming apparatus according to claim 3, wherein the same potential can be applied to each of the electrodes from a single terminal. 5. A carrier for supporting the image-forming particles, a counter electrode arranged to face the carrier, and a carrier arranged between the carrier and the counter electrode to serve as a passage for the image-forming particles. A control electrode having a plurality of gates, the control electrode is provided between the carrier and the counter electrode in order, and a plurality of openings and electrodes provided around the respective openings are provided. The first and second control electrode groups for selectively controlling the flight of the charged visualized particles to the recording medium through the openings corresponding to each other based on the potential applied to the electrodes. And a control means for applying a predetermined potential to a corresponding electrode of the second control electrode group to control passage of the visualized particles through the gate to form an image. Cut off the potential applied to the electrodes of the first and second control electrode groups inside. Voltage switching means for controlling each of the first and second control electrode groups, each of the first and second control electrode groups forming two groups of a plurality of electrodes. An image forming apparatus, comprising: a control means for applying the same potential from a single terminal to any one electrode in each group. 6. The image forming apparatus according to claim 5, wherein a plurality of the carrying members are provided so as to carry a plurality of color developing particles.