JPH11277790A - Image forming method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for forming a good image by controlling the flight of charged particles, i.e., toner, efficiently through a simple arrangement. SOLUTION: An electric field for moving charged particles is formed between a charged particle carrying electrode and a back face electrode 8, an electrode having a plurality of openings 14 is arranged between the charged particle carrying electrode and the back face electrode 8, and movement of charged particles through the moving electric field is controlled by controlling the generation of an electrostatic field in the opening thus forming an image on a recording member placed on the back face electrode 8. The imaging system is provided with an electrode 16 for controlling the passage of charged particles in the opening of an aperture electrode 12 arranged between a developing roller 2 and the back lace electrode 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and an image forming apparatus used for a copying machine, a facsimile, and a printer, for forming an image by ejecting toner to a recording member.

[0002]

2. Description of the Related Art In recent years, the capability of personal computers has been remarkably improved, and accordingly, a large amount of documents (documents) have been handled in offices. In addition, with the advancement of network technology, printers and copiers with high processing ability to cope with instructions from a plurality of personal computers are becoming widespread. Further, color documents are also increasing due to rapid spread of color printers such as ink jet printers. However, an image forming apparatus capable of outputting a black-and-white document or a color document as a clear image including a print speed is currently under development, and the appearance of such an image forming apparatus is expected.

Hereinafter, an image forming method in a conventional image forming apparatus will be described with reference to the drawings. FIG. 8 is a schematic diagram showing an electric signal recording method for image formation described in Japanese Patent Publication No. 44-26333. In FIG. 8, a brush 76 made of fur and a mesh electrode 74 of a mesh body are provided in a toner storage portion for storing a toner 75. Further, a control grid 73 and a back electrode 71 are arranged to face the mesh electrode 74, and the back electrode 71
A recording paper 72 as a recording member is slidably disposed on the side of the control lattice. As shown in FIG.
In contrast, an electric signal whose polarity is changed by a power supply 78 is applied to the control grid 73 for 4. Also,
A DC power supply 77 is provided between the mesh electrode 74 and the back electrode 71.
Are connected to each other, so that a reverse polarity is applied. In the image forming apparatus shown in FIG.
Is negatively charged, for example, by friction with fur due to rotation of the brush 76. The DC power supply 77 is connected between the mesh electrode 74 and the back electrode 71, and
5 is provided to form an electric field that accelerates the recording paper 5 in the direction of the recording paper 72.

In the conventional image forming apparatus configured as described above, when an electric signal is applied between the mesh electrode 74 and the control grid 73, the mesh electrode is controlled according to the polarity and intensity of the applied electric signal. The amount of toner 75 passing through 74 and the position where toner 75 adheres to recording paper 72 are controlled. A parallel electric field for accelerating the toner 75 in the direction of the recording paper 72 is formed between the mesh electrode 74 and the back electrode 71 by the DC power supply 77. In this state, when an "on" signal (a signal having a positive potential when the toner 75 is negatively charged) is applied to the control grid 73 by the power supply 78, the so-called gate of the control grid 73 is opened and the toner 75
Is moved in the direction of the recording paper 72 by the transfer electric field. on the other hand,
When an “off” signal of an electric signal (a signal having a negative potential when the toner 75 is negatively charged) is applied to the control grid 73 by the power supply 78, the so-called gate of the control grid 73 is closed, and the toner 75 is transferred to the control grid 73. And cannot be moved. As described above, the conventional image forming apparatus includes:
An “on” signal of the electric signal and “off”
By applying the signal in combination with the signal, the toner 7
The image is recorded on the recording paper 72 by controlling the movement of No. 5.

FIG. 9 is a schematic diagram showing another configuration of the conventional image forming apparatus disclosed in Japanese Patent Publication No. 2-52260. In FIG. 9, the one-component insulating magnetic toner 11
1 is provided with a toner conveying member 107 having a fixed magnet 112. An insulating member 10 having a hole 104 above the toner conveying member 107
2 are provided adjacent to each other. On both surfaces of the insulating member 102, a signal electrode 101 and a base electrode 103 are formed around a hole 104 of the insulating member 102. Back electrode 1
The recording member 105 is provided on the surface of the recording member 105 facing the signal electrode 101.
Is movably provided. The back electrode 106 is connected to a DC power supply 109, and about 300 V is applied. An AC power supply 108 is connected between the base electrode 103 and the toner conveying member 107. A signal power supply 110 is connected between the signal electrode 101 and the base electrode 103, so that a recording voltage of 50 V is applied. The magnetic blade 114 provided in the vicinity of the toner conveying member 107
7 is provided to charge and regulate the one-component insulating magnetic toner.

Next, the operation of the conventional image forming apparatus shown in FIG. 9 will be described. On the rotating toner conveying member 107, a one-component insulating magnetic toner 111 is formed as a thin layer having a desired thickness by a magnetic blade 114. Base electrode 103 and toner transport member 107
Is applied, an AC or a DC superimposed DC is applied, the one-component insulating magnetic toner 111 is applied to the base electrode 103.
Reciprocation between the printer and the toner conveying member 107 is started.
In this state, when a recording signal is applied to the signal electrode 101, the one-component insulating magnetic toner 111 passes through the hole 104 and adheres to the recording member 105 according to the electric field applied to the back electrode 106. On the other hand, when no voltage is applied to the signal electrode 101 or when a voltage of the opposite polarity is applied, the one-component insulating magnetic toner 111
, And no recording is performed on the recording member 105. Thus, in the conventional image forming apparatus, by controlling the movement of the one-component insulating toner 111,
An image was formed on the recording member 105.

[0007]

The conventional image forming apparatus as described above has the following problems. (1) In the conventional image forming apparatus disclosed in Japanese Patent Publication No. 44-26333 (see FIG. 8), the mesh electrode 7
A method of opening and closing the gate by controlling the parallel electric field formed between the fourth electrode 4 and the back electrode 71 by an electric signal input to the control grid 73, providing a sufficient distance between the mesh electrode 74 and the control grid 73, The opening and closing signal formed by 73 had to work well. For example, in the device shown in FIG. 8, a distance in the range of 500 μm to 2000 μm was required between the mesh electrode 74 and the control grid 73. If the mesh electrode 74 and the control grid 73 are arranged so as to be close to or in contact with each other, a signal having a large voltage difference must be used as an electric signal, and a high-voltage switching element must be used. did not become. Therefore, the image forming apparatus having such a configuration is inevitably increased in size and cost as the apparatus. On the other hand, the mesh electrode 74 and the control grid 7
When the distance between them is large, the controllability of the flying toner becomes poor, and not only a good image cannot be obtained, but also
It did not satisfy the basic performance of the apparatus, such as toner scattering around.

(2) In a conventional image forming apparatus disclosed in Japanese Patent Publication No. 2-52260 (see FIG. 9), a signal electrode 101 and a base electrode 103 are provided on both surfaces of an insulating member 102.
Is formed between the signal electrode 101 and the base electrode 103, and the toner easily adheres to the inner wall surface of the hole 104.
There is a problem that hole clogging by toner is apt to occur.

(3) In the method in which the signal electrode 101 and the base electrode 103 are formed on both surfaces of the insulating member 102, the lines of electric force are always formed between the two electrodes. It easily adheres to the inner wall surface of the hole 104 and requires special cleaning means for removing toner from the hole 104. The image forming method and the image forming apparatus of the present invention are intended to solve the above-described problem, and form an electric field for controlling the flying of the toner in the opening of the control grid. It is an object of the present invention to provide an image forming method and an image forming apparatus that can efficiently control toner flight and form a good image even when the image forming apparatuses are provided close to each other.

[0010]

In order to achieve the above object, an image forming method according to the present invention comprises: forming a transfer electric field for moving charged particles between a charged particle transport electrode and a back electrode; A plurality of openings are arranged between the charged particle transport electrode and the back electrode, and the transfer electric field is generated by independently generating an electrostatic field in the plurality of openings by an aperture electrode whose applied voltage is controlled. Disappearing, preventing passage of the charged particles to the opening, suppressing the generation of an electrostatic field in the opening by the aperture electrode of which the applied voltage is controlled, exposing the transfer electric field, and exposing the charged particles. By permitting passage through the opening, the movement of the charged particles is controlled to form an image. In the above-described image forming method, the transfer electric field for transporting the charged particles is controlled by the presence or absence of an electrostatic field inside the opening formed in the aperture electrode, and a highly accurate image is formed.

The image forming apparatus according to the present invention comprises a charging means for applying a charge to the particles to form charged particles, and a conductive material for transporting the charged particles formed by the charging means. Charged particle transport means to which a predetermined voltage is applied, a back electrode means for directly or indirectly receiving the charged particles, disposed between the charged particle transport means and the back electrode means, a plurality of An insulating member having an opening, and control electrodes formed on at least a part of the inside of the plurality of openings or at least a part of the peripheral edge of the back electrode side exit in the plurality of openings, and applied with independent voltages. And a control power supply for applying a polarity substantially opposite to the charging polarity of the charged particles to the control electrode; and transferring the charged particles from the charged particle transport means to the back electrode means. A transfer power supply for applying a voltage to the charged particle transporting means or the back electrode means, and a voltage applied to the control electrode by the control power supply to control the applied voltage to the charged particles. And a control unit for controlling and forming an image. In the image forming apparatus configured as described above, charging is performed according to the presence or absence of an electrostatic field generated in the opening by the control electrode formed inside the opening of the aperture electrode or the control electrode formed in the peripheral edge of the opening of the opening. The transfer electric field for transporting the particles is controlled, and a good image is formed.

Further, in the image forming apparatus according to the present invention, the control electrode is formed in an annular shape on a wall surface inside the opening. With the image forming apparatus having the above-described configuration, a control electric field can be directly formed inside the opening, and the controllability of the charged particles can be enhanced, and a good image can be formed.

Further, the image forming apparatus according to the present invention comprises a charging means for applying a charge to the particles to form charged particles, and a conductive material for transporting the charged particles formed by the charging means. Charged particle transporting means formed and applied with a predetermined voltage, a back electrode means for directly or indirectly receiving the charged particles, disposed between the charged particle transporting means and the back electrode means, An insulating member having a plurality of openings; a control electrode formed inside each of the plurality of openings, to which a voltage independent of each other is applied; and the control electrode having a polarity substantially opposite to a charging polarity of the charged particles. A deflection power supply for applying a desired voltage to the deflection electrode; a deflection power supply for applying a desired voltage to the deflection electrode; and a control power supply for applying a desired voltage to the deflection electrode. A transfer power supply for applying a voltage to the charged particle transfer means or the back electrode means, and a transfer power supply for applying a voltage to the charged particle transfer means or the back electrode means. A control unit that controls an applied voltage of the control electrode, controls an applied voltage of the deflection electrode by the deflection power supply, and controls movement of the charged particles to form an image. In the image forming apparatus configured as described above, the transfer electric field for transporting the charged particles is controlled by the control electrode formed inside the opening of the aperture electrode or the control electrode formed at the outlet edge of the opening. By controlling the presence / absence of an electrostatic field in the inside, the passage / non-passage of the charged particles is determined, and furthermore, the flying direction and the amount of the charged particles are controlled by the deflection electrode formed on the peripheral edge of the opening of the opening. Good and high-precision images are formed.

Further, in the image forming apparatus according to the present invention, the deflecting electrode is constituted by a first deflecting electrode and a second deflecting electrode formed near each opening, and the first deflecting electrode and the second deflecting electrode are formed. A voltage is applied independently to the second deflecting electrode to control the transfer direction of the charged particles.
In the image forming apparatus configured as described above, the first deflecting electrode and the second deflecting electrode of the deflecting electrode formed on the periphery of the outlet of the opening are provided.
By controlling the flight direction and amount of charged particles by the deflection electrode, a good and high-accuracy image can be formed with a small number of parts.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS. << First Embodiment >> A first embodiment, which is one embodiment of the image forming apparatus of the present invention, will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing the structure of an image forming apparatus according to a first embodiment of the present invention. In FIG. 1, a developing roller 2 as a charged particle transporting unit transports a toner 50 supplied from a supply roller 6 to an image forming position. The regulating blade 4 forms the toner 20 on the developing roller 2 to a predetermined thickness and charges the toner 50.

As shown in FIG. 1, an aperture electrode 12 and a back electrode 8 are arranged to face the image forming position of the developing roller 2, and a recording paper 20 is placed on the surface of the back electrode 8 facing the developing roller 2. It is arranged movably. A plurality of openings 14 are formed in the aperture electrode 12 so as to face the image forming position, and an annular control electrode 16 is formed on a wall surface inside the opening 14. The developing roller 2 in the image forming apparatus of the present invention is formed of a metal such as aluminum or iron,
Or, they are composed of these alloys. The developing roller 2 of the first embodiment is formed using an aluminum cylinder having an outer diameter of 20 mm and a thickness of 1 mm. Although the developing roller 2 of the first embodiment is grounded, the image forming apparatus of the present invention is not limited to this, and a DC or AC voltage may be applied.

The regulating blade 4 is made of an elastic member such as urethane and has a hardness of 40 to 80 degrees (JIS).
K6301 A scale), the free end length (length of the portion protruding from the mounting member) is 5 to 15 mm, and one to three toner layers are formed on the developing roller 2 by the regulating blade 4. The regulating blade 4 is used in an electrically floating state, a grounded state, or by applying a DC or AC voltage. The regulating blade 4 of the first embodiment is used in a floating state. The toner 50 on the developing roller 2 is sandwiched between the developing roller 2 and the regulating blade 4, receives a small charge from the developing roller 2, and charges the toner.

The supply roller 6 is provided with a synthetic rubber such as foamed urethane having a thickness of about 2 to 6 mm on a metal shaft such as iron (diameter 8 mm in the first embodiment). Is 30 degrees (rolled into JIS K63
01 A scale method). Supply roller 6
Is preferably in the range of 0.1 to 2 mm. The supply roller 6 is used by being grounded or by applying a DC voltage or an AC voltage, and assists the charging of the toner 50 and also controls the supply of the toner 50. Although the back electrode 8 of the first embodiment is made of a metal plate, it may be made of a film in which a conductive filler is dispersed in a resin. In this case, the resistance of the film is 10 ² to 10 ¹⁰ Ω
-About cm is preferable.

When an image is to be formed, the recording paper 20 is placed on the back electrode 8 and toner adheres to the recording paper 20, or the toner 50 is applied to the film-shaped back electrode 8.
May be directly attached. When the toner 50 is directly attached to the back electrode 8, the back electrode 8 is processed into an endless film shape, the toner 50 is directly attached to the film to record an image, and then the film is transferred to recording paper. To be configured. The distance between the back electrode 8 and the aperture electrode 16 is preferably in the range of 50 to 1000 μm. In this range, a good toner image was formed on the recording paper 20. The aperture electrode 12 is formed of an insulating film having an opening group having a plurality of openings 14, and a control electrode 16 is formed on a wall surface inside each opening 14. The insulating film constituting the aperture electrode 12 preferably has a thickness of 10 to 100 μm, and is formed of an insulating material such as polyimide or polyethylene terephthalate.

FIG. 2 is a side sectional view (a) and a plan view (b) showing a part of the aperture electrode 2. As shown in FIG. 2A, the control electrode 16 is formed on a wall surface inside the opening 14. As shown in FIG. 2B, each control electrode 16
Lead wires 18 are connected to each control electrode 16 and the control power supply 22. The lead wire 18 is formed as a conductive pattern on the insulating film. FIG.
The openings 14 shown in FIG. 3B are greatly separated from each other. However, in practice, when the toner 50 is blown out from all the openings 14 and recorded on the recording paper 20, an all black image can be formed. The openings 14 are arranged in a staggered manner at a distance complementary to each other. In order to form a good image, the diameter of the opening 14 is preferably 50 to 200 μm. In the first embodiment, the diameter D of the opening 14 is 150 μm, and the thickness t of the control electrode 16 formed on the inner wall surface of the opening 14.
Is about 10 μm, and the inner diameter d of the opening 14 is 130 μm.

The control electrode 16 is made of a metal such as copper, and preferably has a thickness t of 5 to 30 μm. Each control electrode 16 is independently connected to a control power supply 22 via a lead wire 18. The control power supply 22 connected to the control electrode 16 includes a voltage generator (not shown) for outputting a desired voltage and a switching element for switching the output voltage. One of the switching elements has about 32, 64, 128 channels,
In this configuration, the voltage supplied to the control electrode 16 via the lead wire 18 can be controlled. For example, 30 per inch
When recording at a recording density of 0 dots (300 dpi), if a switching element of 64 channels is used, 30 dots can be obtained.
To control 0 openings, 5 switching elements having 64 channels are required.

FIG. 3 shows a voltage waveform applied to the control electrode 16 with the vertical axis representing voltage and the horizontal axis representing time. FIG.
In the above, Tt indicates the time required to form one dot, and is determined by the resolution. For example, 300dp
In order to form i (dot / inch) dots, one inch (i
nch) If 25.4 mm is divided by 300 dots (Dot), the diameter of one dot is about 83 μm. Recording paper 20 during Tt
Need only be moved by one dot. If the speed of the recording paper 20 is, for example, 60 mm / s, the time Tt is about 13 mm.
Calculated as 90 μs.

Tb indicates a time for exposing the transfer electric field formed by the developing roller 2 and the back electrode 8 to fly the toner 50 to the control electrode 16. This time Tb
Needs to be longer than the time required for the toner 50 to separate from the developing roller 2 and reach the back electrode 8.
It is almost determined from the charge amount, weight, and electric field. For example, one particle diameter of the toner 50 is 10 μm, and the charge amount is 5 μC.
/ G, the density is 1.2 g / cm ³ , the voltage applied between the back electrode 8 and the developing roller 2 is 1000 V, the equation of motion (ma = qE, m is mass, a is acceleration, q is one toner particle) From the acceleration of the applied electric field), Tb
Is calculated to be about 200 μs. Tw indicates the time during which the transfer electric field formed between the developing roller 2 and the back electrode 8 is extinguished and an electrostatic field for preventing the movement of the toner 50 is generated. Therefore, the same polarity as the charging polarity of the toner 50 is applied to the control electrode 16. In the first embodiment, -300 V is applied to the control electrode 16.

According to the above-described example, a voltage at which the movement of the toner 50 is prevented is applied to the control electrode 16 at a time of about 1190 μs, which is the difference between Tt = 1390 μs and Tb = 200 μs. That is, in the above process, the toner 50 flies by the transfer electric field formed between the developing roller 2 and the back electrode 8, and the movement of the toner 50 is prevented by the control electrode 1.
6 by a blocking voltage applied. The above-mentioned time T
b, the toner 50 is drawn in to
A voltage having a polarity opposite to the charging polarity may be applied to the control electrode 16.

FIG. 4 shows a structure (a) near the conventional aperture electrode and a structure (b) near the aperture electrode according to the present invention.
FIG. In FIGS. 4A and 4B,
The size of the opening formed in the aperture electrode and the distance between the components are the same. The difference between the conventional aperture electrode and the aperture electrode of the present invention will be described with reference to FIG. 4 using equipotential lines. FIG. 4A shows the structure of a conventional aperture electrode.
1 is formed on the upper surface (the surface facing the developing roller 2). As shown in FIG. 4A, the control electrode 160 is formed at a position away from the inner wall surface of the aperture 140 of the aperture electrode to the outside. FIG. 4B shows the structure of the aperture electrode of the present invention, in which the control electrode 16 is formed on the inner wall surface of the opening 14. For example, the control electrode 16
When a negative polarity having the same polarity as the charging polarity of the toner 50 is applied, equipotential lines are formed concentrically around the control electrode 16 as shown in the figure. A transfer electric field (the developing roller 2 is grounded and +1000 V is applied to the back electrode 8) is originally formed between the developing roller 2 and the back electrode 8 to cause the toner 50 to fly. When a negative voltage, which is a blocking voltage, is applied, (b) in FIG.
, The starting point b of the transfer electric field indicated by the arrow B is pushed out below the aperture electrode 12 (back electrode side).

On the other hand, in the structure of the conventional aperture electrode shown in FIG.
4A, a starting point a of the transfer electric field indicated by an arrow A in FIG. As described above, in the state shown in FIG. 4A, the starting point a of the transfer electric field A is inside the opening 140, and in the state shown in FIG. It is pushed out of the opening 14. The reason why the starting point b of the transfer electric field B is outside the opening 14 is that the equipotential lines become dense inside the opening 14 because the control electrode 16 is provided inside the opening 14.
The transfer electric field formed between the developing roller 2 and the back electrode 8 as described above is applied to the control electrode 1 formed inside the opening 14.
By applying a voltage that repels the charging polarity of the toner 50 to the toner 6, the toner can be efficiently and reliably eliminated. First
The image forming apparatus according to the embodiment controls the image formation by combining the transfer electric field and the blocking electric field thus formed, and forms a good image on the recording paper.

Next, the overall operation of the image forming apparatus according to the first embodiment will be described with reference to FIG. FIG. 5 is a schematic configuration diagram illustrating a configuration of the image forming apparatus according to the first embodiment. The image forming apparatus according to the first embodiment shown in FIG.
Is an apparatus having a configuration in which an intermediate transfer belt 30 as an intermediate transfer member is provided at a position of a recording sheet in the image forming apparatus shown in FIG. In FIG. 5, the intermediate transfer belt 30 provided opposite to the image forming position of the developing roller 2 is made of a film in which a conductive filler is dispersed in a resin, and has a resistance of 10 ⁸ Ω · cm. The intermediate transfer belt 30 is arranged at a position facing the opening 14 of the aperture electrode 12, and is contacted behind the intermediate transfer belt 30 and supported by the back electrode 8.

The pickup roller 32 is provided for feeding out the recording paper 20 one by one from the paper supply tray, and the timing roller 34 is provided for adjusting the image position with the supplied recording paper 20. . The recording paper 20 sent from the timing roller 34 is supplied to the transfer roller 36, and the toner image formed on the intermediate transfer belt 30 is transferred to the recording paper 20. Transfer roller 3
No. 6 is obtained by conducting a conductive treatment of a foam sponge such as urethane on a metal roller, and has an outer diameter of 20 mm and a hardness of JIS.
It is about 30 degrees on the K6301 A scale. The transfer roller 36 has both ends of the metal shaft of about 500 to 1000 g.
At an intermediate transfer belt 30. The resistance of the transfer roller 36 was about 10 ⁶ to 10 ⁷ Ω · cm by pressing the grounded metal plate with the above-described pressure and applying 500 V to the metal shaft. The recording paper 20 to which the toner image has been transferred is sent to a fixing device 38, and the toner image formed on the recording paper 20 is fixed by pressure and heat.

Since the toner used in the first embodiment is fixed to the recording paper 20 by melting the resin by heat, the resin is a styrene-acrylic copolymer or a styrene-butadiene copolymer. Polymers, polyester resins, epoxy resins and mixed resins thereof are suitable. The toner used in the first embodiment may be a magnetic toner containing a magnetic powder. In this case, as the magnetic powder, ferrite such as ferrite, magnetite, iron, cobalt, nickel, etc. Alloys, compounds, and the like containing the elements showing It is appropriate that the magnetic powder has a holding power of 100 to 500 Oe.
0% by weight is suitable.

As the toner used in the first embodiment, in addition to the above, silica (SiO 2), titanium oxide (TiO 2), a metal salt of stearic acid, etc. may be used to control the fluidity of the toner. It is preferable to add 0.1 to 5% by weight. In particular, silica greatly affects the fluidity and can prevent the toner from clogging the opening 14. In addition, since silica has a small diameter and a high chargeability, it is strongly attracted by electric force and easily adheres to a wall surface around the aperture electrode 12, and plays a role of a roller that promotes the movement of the toner when passing through the opening 14. It has the effect of avoiding clogging. Silica has a BET specific surface area of 100 to 300 m ² /
Those in the range of g are suitable. If silica having a small diameter of less than 100 m ² / g is used, sufficient fixing property cannot be obtained since the resin is mixed so as to be shredded.

Next, an image forming operation in the image forming apparatus of the first embodiment configured as described above will be described. The aperture electrode 12 has a resolution of, for example, 300 dp.
i has 300 openings 14 per inch. The plurality of openings 14 are arranged in a zigzag pattern in the width direction of the recording paper 20 so as to face the back electrode 8. The control electrode 16 is formed in each opening 14 and is connected to a plurality of switching elements via leads. According to the image data, each control electrode 16 combines the voltage waveforms shown in FIG. 3 to transfer the toner to the intermediate transfer belt 30 to form an image. In the above embodiment, the control electrode 16 is connected to the opening 1.
Although the control electrode 16 is formed on the entire surface of the inner wall surface of the opening 4, the control electrode 16 is formed by forming a control electrode on the periphery of the outlet of the opening 14 (the periphery of the back electrode) to control the generation of an electric field in the opening. It is also possible to control the passage / non-passage of the toner as the charged particles in the opening.

In the first embodiment, the distance between the developing roller 2 and the aperture electrode 12 is about 50 μm.
The distance between the aperture electrode 12 and the back electrode 8 is about 5
0 μm. Therefore, in the image forming apparatus of the first embodiment, the distance between the developing roller 2 and the back electrode 8 is configured to be much shorter than that of the conventional apparatus (500 μm or more). A voltage of about +1000 V is applied to the back electrode 8 in advance. The toner image formed on the intermediate transfer belt 30 is transferred to the recording paper 20 fed to the transfer roller 36 in synchronization with the toner image. At this time, a voltage of about +500 V is applied to the intermediate transfer belt 30 from the back surface by the transfer roller 36. Recording paper 20
The transferred toner image is fixed to the recording paper 20 by the fixing roller 38, and the recording paper 20 is discharged outside the apparatus. As described above, according to the image forming apparatus of the first embodiment, the distance between each of the developing roller 2, the aperture electrode 12, and the back electrode 8 can be set shorter than that of the conventional apparatus. It is possible to form a good image reliably and efficiently by controlling the image quality.

<< Second Embodiment >> Next, a second embodiment of the image forming apparatus of the present invention will be described with reference to FIG. FIG.
FIG. 4 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to a second embodiment. 6, the same reference numerals denote the same functions and configurations as those of the image forming apparatus of the first embodiment, and a description thereof will be omitted. The image forming apparatus according to the second embodiment shown in FIG. 6 differs from the first embodiment in that two deflection electrodes having a function different from that of the control electrode 16 are provided on the back electrode 8 side of the aperture electrode 12. 48a, 4
8b. Deflection electrode 48 of the second embodiment
Reference numerals a and b denote not a control electrode for extracting the toner from the developing roller 2 but for deflecting the transfer direction of the toner after the toner is extracted. The transfer direction of the toner is changed by the voltage applied to the deflection electrodes 48a and 48b.

In the image forming apparatus of the second embodiment, the toner is moved from the developing roller 2 to the back electrode by the transfer electric field formed between the developing roller 2 and the back electrode 8, and the toner is transferred to the recording paper. Reach 20. On the other hand, when blocking the passage of the toner through the opening 14, a voltage for preventing the transfer of the toner is applied to the control electrode 16 formed in the opening 14, and the movement of the toner to the recording paper 20 is prevented. As described above, the image forming apparatus according to the second embodiment, like the image forming apparatus according to the above-described first embodiment, forms an image by combining the two states of the toner movement permission state and the toner movement permission state. It is formed. As described above, in order to form a good image by combining the two states of permitting and preventing the toner from passing through the opening, a voltage is applied to the deflection electrodes 48a and 48b after the toner passes through the opening 14. To prevent toner from passing therethrough.
The permission of toner passage is performed by not applying a voltage to a and b.

As shown in FIG. 6, the deflecting electrodes 48a and 48b formed on the back surface of the aperture electrode 12 (the surface facing the back electrode 8) are provided on the first electrode above the control electrode 16.
The upper electrode 48a, which is a deflecting electrode, and the lower electrode 48b, which is a lower second deflecting electrode.
The upper electrode 48a and the lower electrode 48b of the deflection electrode are independently connected to and controlled by a power supply (not shown). For example, when a large negative voltage is applied to the upper electrode 48a of the deflection electrode and a small negative voltage is applied to the lower electrode 48b, the negatively charged toner causes electrostatic repulsion with the upper electrode 48a, and Bend in the direction of 48b. When the magnitudes of the voltages applied to the upper electrode 48a and the lower electrode 48b are reversed, the toner causes electrostatic repulsion with the lower electrode 48b and bends toward the upper electrode 48a. By controlling the voltages applied to the two deflecting electrodes 48a and 48b as described above, it is possible to change the toner transfer direction from one opening 14 to three directions of upward, downward, and rectilinear.

FIG. 7 shows an example of voltage waveforms applied to the control electrode 16, the upper electrode 48a of the deflection electrode, and the lower electrode 48b of the deflection electrode. The voltage waveform of FIG. 7A is a voltage waveform applied to the control electrode 16 and is the same as the voltage waveform shown in FIG. The voltage waveform of FIG. 7B is a voltage waveform applied to the upper electrode 48a, and the voltage waveform of FIG. 7C is a voltage waveform applied to the lower electrode 48b. In FIG. 7, the horizontal axis represents time and the vertical axis represents applied voltage, and the respective voltage waveforms are shown. FIG.
As shown in (1), the voltage waveform applied to the upper electrode 48a and the lower electrode 48b is synchronized with the voltage waveform applied to the control electrode 16.

Next, the change control of the toner transfer direction by the deflection electrodes 48a and 48b will be specifically described with reference to FIG. As shown in FIG. 7, first, the upper electrode 48a
, A large negative voltage is applied (about -250 V in the second embodiment), and a small negative voltage is applied to the lower electrode 48b (about -50 V in the second embodiment). By applying different voltages to the deflecting electrodes in this way, the toner that has jumped out of the opening 14 is bent toward the lower electrode. Subsequently, the same potential voltage (approximately −100 V in the second embodiment) is applied to the upper electrode 48a and the lower electrode 48a. For this reason, the toner that jumps out of the opening 14 is transported straight without being bent.

Subsequently, a small negative voltage (about -50 V in the second embodiment) is applied to the upper electrode 48a and a large negative voltage is applied to the lower electrode 48b so that the toner bends in a direction opposite to the first transfer direction. Voltage (in the second embodiment,
About -250V) is applied. Thus, the transfer direction of the toner is changed in three directions by the deflection electrodes 48a and 48b. If no signal is input to the control electrode 16,
Since the toner transfer operation does not occur, the applied voltage pattern shown in FIG. 7 may be repeatedly applied to the upper electrode 48a and the lower electrode 48a of the deflection electrode. The present invention is not limited to the voltage waveform of the applied voltage pattern shown in FIG. 7, and the magnitude and timing of the voltage applied to each deflecting electrode are determined according to the distance and direction in which the toner is deflected. The waveform is selected. For example, the developing roller 2
The distance between the electrode and the aperture electrode 12 is about 30 to 50 μm
In this case, it takes about 20 to 40 μs for the toner to leave the developing roller 2 and reach the opening 14. Therefore, the timing of applying a voltage to the deflection electrode is 30 to 50 from the beginning of the image forming period (Tt in FIGS. 3 and 7).
With a configuration in which a desired voltage is applied to the deflection electrode with a delay of μs, a highly accurate image is efficiently formed.

As described above, according to the image forming apparatus of the second embodiment, the transfer direction of toner is adjusted by the deflection electrode provided near the opening 14 on the back electrode side of the aperture electrode 12 to form an image. In addition to this, a plurality of dots can be formed from one opening. For this reason, the image forming apparatus of the second embodiment can form a desired image with a smaller number of openings than the conventional apparatus, and can reduce the number of switching elements for controlling the passage / non-passage in each opening. Therefore, it is a device that greatly contributes to cost reduction.

[0040]

The image forming method and the image forming apparatus of the present invention have the following effects. In the image forming method of the present invention, a transfer electric field for moving charged particles is formed between the charged particle electrode and the back electrode, and an aperture electrode having a plurality of openings is arranged between the charged particle electrode and the back electrode. By controlling the generation of an electrostatic field that prevents charged particles from passing through the opening, the toner is efficiently controlled, and a good image can be reliably formed. Further, according to the image forming apparatus of the present invention, a transfer electric field for moving charged particles is formed between the charged particle electrode and the back electrode, and the control electrode is formed in the opening of the aperture electrode having a plurality of openings. By controlling on / off of this control electrode, the generation of an electrostatic field that prevents charged particles from passing through the opening is controlled, so that toner is efficiently controlled without scattering and a good image can be formed with a small device. Can be. Further, according to the image forming apparatus of the present invention, the transfer electric field for moving the charged particles controls the generation of the electric field in the opening by the control electrode formed inside the opening formed in the aperture electrode. In addition to controlling the passage / non-passage through the opening and controlling the flight direction and amount of the charged particles by the deflection electrode formed near the periphery of the opening, a good image can be formed with a small number of components. Further, in the image forming apparatus of the present invention, by forming the control electrode in the opening of the aperture electrode having a plurality of openings and performing on / off control, adhesion of toner to the inner surface of the opening is significantly suppressed, and This has the effect that no special cleaning means for removing toner is required.

[Brief description of the drawings]

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

FIG. 2A is a sectional view of an aperture electrode according to a first embodiment of the present invention, and FIG. 2B is a plan view of the aperture electrode.

FIG. 3 is a waveform diagram showing a voltage waveform applied to a control electrode according to the first embodiment of the present invention.

4A is a diagram showing a schematic configuration of a conventional aperture electrode together with an equipotential curve, and FIG. 4B is a diagram showing the configuration of the aperture electrode of the present invention together with an equipotential curve.

FIG. 5 is a configuration diagram illustrating a configuration of the image forming apparatus according to the first embodiment of the present invention.

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

FIG. 7 is a waveform chart showing voltage waveforms applied to control electrodes and deflection electrodes in the image forming apparatus according to the second embodiment of the present invention.

FIG. 8 is a schematic configuration diagram illustrating a conventional image forming apparatus.

FIG. 9 is a schematic configuration diagram illustrating another conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 2 developing roller 4 regulating blade 6 supply roller 8 back electrode 10 transfer power supply 12 aperture electrode 14 opening 16 control electrode 20 recording paper 22 control power supply 50 toner

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsutoshi Ogawa 1006 Kadoma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Hiroyuki Matsuo 1006 Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A method for forming a transfer electric field for moving charged particles between a charged particle transport electrode and a back electrode, comprising a plurality of openings between the charged particle transport electrode and the back electrode. Applying an applied voltage controlled aperture electrode to independently generate an electrostatic field in the plurality of openings to eliminate the transfer electric field and prevent the charged particles from passing through the openings; and Controlling the movement of the charged particles by controlling the generation of an electrostatic field in the opening by the controlled aperture electrode, exposing the transfer electric field, and permitting the charged particles to pass through the opening. An image forming method comprising forming an image. 2. A charging means for applying a charge to the particles to form charged particles, and a charging means for transferring the charged particles formed by the charging means, wherein the charging means is formed of a conductive material and is applied with a predetermined voltage. Particle transport means, a back electrode means for directly or indirectly receiving the charged particles, an insulating member disposed between the charged particle transport means and the back electrode means and having a plurality of openings, the plurality of openings A control electrode formed on at least a part of the inside of at least one or at least a part of the peripheral edge of the back electrode-side exit in the plurality of openings, to which voltages independent of each other are applied; A control power supply for applying a voltage of the opposite polarity to the control electrode, for forming a transfer electric field for moving the charged particles from the charged particle carrying means to the back electrode means. Provided in
A transfer power supply for applying a voltage to the charged particle transport means or the back electrode means, and a control unit for controlling an applied voltage of the control electrode by the control power supply to control the charged particles to form an image. An image forming apparatus comprising: 3. The image forming apparatus according to claim 2, wherein the control electrode is formed in a ring shape on a wall surface inside the opening. 4. A charging means for applying a charge to the particles to form charged particles, and a charging means for transferring the charged particles formed by the charging means, the charging means being formed of a conductive material and applying a predetermined voltage. Particle transport means, a back electrode means for directly or indirectly receiving the charged particles, an insulating member disposed between the charged particle transport means and the back electrode means and having a plurality of openings, the plurality of openings A control electrode formed inside each of the first and second electrodes, to which independent voltages are applied; a control power supply for applying a polarity substantially opposite to a charging polarity of the charged particles to the control electrode; and the back surface of the insulating member. A deflecting electrode formed in the vicinity of the periphery of the opening on the electrode side; a deflecting power supply for applying a desired voltage to the deflecting electrode; A transfer power supply for applying a voltage to the charged particle transporting means or the back electrode means, and a voltage applied to the control electrode by the control power supply; An image forming apparatus comprising: a control unit that controls an applied voltage of the deflection electrode to control movement of the charged particles to form an image. 5. The deflecting electrode comprises a first deflecting electrode and a second deflecting electrode formed in the vicinity of each opening, and is independent of the first deflecting electrode and the second deflecting electrode. 5. The image forming apparatus according to claim 4, wherein a voltage is applied to control a transfer direction of the charged particles.