JPH11268320A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of nonuniformity in toner density and form constant-quality images stably by controlling an adhesion force of toner to a toner hold roller and feeding the toner smoothly to an aperture. SOLUTION: A negative voltage is impressed by a d.c. power source 49 to roller electrodes 41a in the vicinity of immediately below an aperture 6 and a positive voltage is impressed by a d.c. power source 32 to an auxiliary electrode 31 set at a print head 1, whereby the roller electrodes 41a act a repulsion force to a toner 16 and the auxiliary electrode 31 acts an attraction force. Accordingly, an adhesion force between a toner hold roller 14 and the toner 16 is eased to a degree not allowing the toner 16 to fly. Since the toner 16 can be supplied smoothly to the aperture 6 by controlling a voltage of a control electrode 4, constant-quality images can be formed stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus applied to a copying machine, a printer, a facsimile, a plotter, and the like, and more particularly to a toner flow control in a recording mechanism.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus, an image forming apparatus which applies an image signal voltage to an electrode having a toner flow path to control the passage of toner particles to obtain an image on a recording medium, and Japanese Patent Application Laid-Open No. 6-255163), a device using an opening (aperture) as a toner flow path (Japanese Patent Application Laid-Open No. 6-255163).
155798) and the like. These conventional image forming apparatuses include a print head including an insulating sheet having toner electrodes arranged in rows and having control electrodes corresponding to the toner channels, and a toner carrying roller for carrying toner. Is arranged in contact with the peripheral surface of the toner carrying roller near the toner channel row. In recording by this image forming apparatus, a voltage corresponding to the image data is applied to the control electrode to control the passage of the charged toner through the aperture, and to the recording medium disposed on the opposite side of the print head from the toner carrying roller. This is performed by forming a toner image.

According to the above-described image forming apparatus, since the toner on the toner carrying roller and the print head slide in contact with each other near the toner flow path, the following advantages are provided. (1) The toner that adheres to the vicinity of the toner flow path and tries to hinder the flow of the toner is scraped off by the toner that is transported later, so that the flow of the toner is not hindered.
(2) The toner adhering to the toner carrying roller adheres to the surface of the toner carrying roller by a physical force such as a mirror image force and a van der Waals force due to charging of the toner. Due to the mechanical force of sliding with the print head, the toner rolls or slightly floats on the surface of the toner carrying roller, so that with a small control voltage, the toner is released from the above-mentioned adhesive force and passes through the toner flow path. Can be controlled. (3) Since the control electrode on the print head and the toner carrying roller at the ground potential are extremely close to each other, a strong electric field can be obtained even with a small control voltage, and the toner flow can be controlled with a smaller voltage. , High contrast can be obtained.

[0004]

However, in the conventional image forming apparatus as described above, the toner on the toner carrying roller is sandwiched between the print head and the toner carrying roller while receiving a constant pressure. Since the toner is conveyed to the flow path, the toner adheres to the toner carrying roller and the print head due to long-term use, and the conveyance and supply of the toner to the toner flow path may be hindered. As a result, the state of toner supply in a large number of toner flow paths becomes non-uniform, causing problems such as uneven density in a formed image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to change the potential of the surface of a toner carrying roller and the adhesive force of the toner on the surface of the toner carrying roller to change the toner flow path. It is an object of the present invention to provide an image forming apparatus capable of stably forming an image of constant quality without unevenness in density by smoothly conveying and supplying the toner to the image forming apparatus.

[0006]

In order to achieve the above object, an image forming apparatus according to the first aspect controls a charged material flow path through which a charged material passes and a passage of the charged material in the charged material flow path. A charged body flow control means having a control electrode to be charged, and a charged body supply means for carrying a charged body on the surface and supplying the charged body to the charged body flow control means. The passage of the charged body through the charged body flow path is controlled by the charged body flow control means, and the charged medium is supplied to the recording medium located on the opposite side of the charged body flow control means with respect to the charged body flow control means. An image forming apparatus for forming an image by flying a body, wherein a charged body supply means has a variable surface potential, and is configured to change a loaded state of a charged body by changing the surface potential. What was done That.

[0007] In the above configuration, by changing the surface potential of the charged body supply means, the charged body is normally charged from the surface potential of the charged body supply means when the charged body is carried on the surface of the charged body supply means. If the surface potential is set so as to repel the charge, the adhesive force between the charged body and the charged body supply means is reduced, and the charged body is easily separated from the surface of the charged body supply means. The passage of the charged material having reduced adhesion in the charged material flow path is controlled by the charged material flow control means, and the charged material is charged on the recording medium located on the opposite side of the charged material flow control means with respect to the charged material flow control means. By flying the body, the charged body is smoothly supplied to the charged body flow path, and a stable image of constant quality can be formed.

[0008] The image forming apparatus according to claim 2 is
2. The image forming apparatus according to claim 1, further comprising a voltage applying unit that applies a voltage so that the surface potential of the charged body supply unit differs at each part of the surface of the charged body supply unit.

In the above arrangement, the voltage applying means optimally sets the surface potential of the charged material supply means in accordance with the supply position, the transport position, and the flying position of the charged material, and charges the toner only in the vicinity of the flying position of the toner. It is possible to reduce the adhesive force between the body and the charged body supply means. By controlling the passage of the charged material having the reduced adhesive force in the charged material flow path by the charged material flow control means, it is possible to smoothly transfer and supply the toner from the charged material supply means to the charged material flow path. It can be carried out.

The image forming apparatus according to claim 3 is
3. The image forming apparatus according to claim 2, wherein the voltage applying unit sets the surface charge of the charged body supply unit stepwise in the charged body supply direction.

[0011] In the above configuration, the surface potential of the charged body supply means is changed stepwise as the charged body approaches the charged body flow path, and the charged body and the charged body supply means are connected near the flying position of the charged body. It is possible for the adhesion to be lessened than at other locations. Thereby, at the supply position / transport position of the charged body in the charged body supply means, the adhesion between the charged body and the charged body supply means is increased, and the supply / conveyance of the charged body is performed reliably. At the flying position, it is possible to smoothly transfer and supply the toner from the charged body supply unit to the charged body flow path.

[0012] The image forming apparatus according to claim 4 is
3. The image forming apparatus according to claim 2, wherein the voltage applying unit changes the surface charge only in the vicinity of the charged material flow path.

In the above structure, the voltage applying means can reduce the adhesive force between the charged body and the charged body supply means only in the vicinity of the charged body flow path of the charged body, that is, only in the vicinity of the flying position. By doing so, it is possible to provide a difference between the adhesion of the charged body at the flight position and the adhesion of the charged body at another position, so that both the conveyance and the supply of the charged body by the charged body supply unit are performed. It can be done reliably.

The image forming apparatus according to a fifth aspect of the present invention provides
3. The image forming apparatus according to claim 2, wherein the voltage applying unit has a surface potential of a portion immediately below the charged material flow path in the charged material supply unit having the same sign as a charge of the charged material carried by the charged material supply unit. 4. A voltage is applied so as to be a potential.

In the above configuration, since the surface potential of the charged body supply means at the flying position of the charged body has the same sign as the charge of the charged body, the charged body supply means exerts a repulsive force on the charged body, and Adhesive force to the charged material supply means is reduced, and flying becomes easier.

Further, the image forming apparatus according to claim 6 is
6. The image forming apparatus according to claim 1, wherein the charged body supply unit is a cylindrical roller member, and the charged body is rotatably supported around a cylindrical central axis. It has a carrying roller and is provided with a plurality of long electrodes extending in the longitudinal direction on the surface of the charged body carrying roller.

In the above configuration, by applying a voltage to each of the plurality of long electrodes, the adhesion between the charged body and the charged body supply means is made uniform in the longitudinal direction of the roller, and Can be easily controlled so as to be freely changed in the rotation direction (charged material supply direction). Further, by arranging the charged material flow paths of the charged material flow control means so as to be aligned in the longitudinal direction of the roller, the adhesive force between the charged material and the charged material supply means is reduced only at the flight position. It is also possible to cope with a plurality of charged material flow paths uniformly with a simple configuration. The passage of the charged material having the reduced adhesive force is controlled by the charged material flow control means, and the charged charge passing through the charged medium supply means on the recording medium located on the opposite side of the charged material flow control means. By flying the body, it is possible to smoothly transfer and supply the toner from the charged body supply means to the charged body flow path with a simple configuration, and to form a stable quality image on the recording medium. Can be.

Further, the image forming apparatus according to claim 7 is
7. The image forming apparatus according to claim 1, wherein the charged material flow control unit has a sign opposite to a charge of the charged body on the charged body supply unit. It is provided with auxiliary control means capable of applying a DC voltage.

In the above-mentioned configuration, when the DC voltage applied to the charged body by the auxiliary control means of the charged body flow control means is opposite to that of the charge of the charged body, the flying position of the charged body and its vicinity are determined. It is possible to further enhance the relaxation of the adhesive force between the charged body and the charged body supply means.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view illustrating a print head portion provided in the image forming apparatus. The image forming apparatus has a toner supply device 10 as a charged material supply unit, and a print head (charged material flow) for controlling the flow of toner 16 as a charged material is provided above the toner supply device 10. (Control means) 1 is provided. Above the print head 1, a back electrode roller 22 is rotatably supported with an interval of about 1 mm, and the gap between the print head 1 and the back electrode roller 22 is a recording medium 2.
0 is conveyed. The recording medium 20 is rotated by the rotation of the back electrode roller 22 (in the direction of arrow D) shown in FIG.
Is conveyed in the direction of arrow C by the rotation of. Recording medium 2
A thermal fixing device 26 including a pair of a pressure roller and a heating roller is provided at the destination of 0. This heat fixing device 26
Can be replaced by any of the heat fixing system and the pressure fixing system.

Next, the details of each component will be described.
The toner supply device 10 is housed in a toner case 11 also serving as a housing for the entire device.
A charged body, preferably an insulating toner 16, and a cylindrical roller-shaped toner carrying roller (a charged body carrying roller) 14 that carries the toner 16 and transports it toward the print head 1 are provided therein. . The toner carrying roller 14 is
The roller is rotated by a driving force of a rotation driving motor attached to one end of the roller rotation shaft. In FIG. 1, a cylindrical supply roller 12 for supplying the toner 16 contained in the toner case 11 to the toner carrying roller 14 is provided rotatably in the direction of arrow A below and to the left of the toner carrying roller 14. Have been. The supply roller 12 and the toner carrying roller 14 are arranged in parallel so that their cylindrical surfaces are in contact with each other.

Above the supply roller 12 in the toner case 11, the amount of the toner 16 carried by the toner carrying roller 14 is adjusted so as to be uniform on the roller surface of the toner carrying roller 14. Toner layer regulating blade 1 for uniformly charging toner 16
8 are provided. The toner layer regulating blade 18 is pressed so that a part thereof is pressed against the toner carrying roller 14.
It is fixed to the toner case 11 and disposed. In addition,
A drive element 8 for controlling these operations is connected to the toner carrying roller 14 and the print head 1, and a DC power supply 24 for applying a voltage is connected to the back electrode roller 22.

As shown in FIG. 2, the print head 1 is
For example, an insulating base 2 made of polyimide having a thickness of about 25 μm is used as a base material, and is composed of an aperture (charger flow path) 6 and a control electrode 4 formed around the aperture 6.
The aperture 6 has a plurality of apertures having a diameter of about 60 μm in the base 2 and is formed in a line in the longitudinal direction of the print head 1. The control electrode 4 is provided around these apertures 6
It is formed as a conductive metal pattern having a thickness of about 5 μm such as copper or gold. On a surface of the base 2 opposite to the surface on which the control electrodes 4 are formed, an auxiliary electrode (auxiliary control means) 31 formed of a conductive metal pattern such as a long and narrow copper or gold is provided to the aperture 6. It is provided at a position near the toner supply side.

The details of the print head 1 will be described with reference to FIG. FIG. 3 is a configuration diagram near the print head 1. As shown in FIG. 3, the print head 1 has a base 2 attached with a predetermined gap from the surface of the toner carrying roller 14 and the toner (not shown in FIG. 3) carried on the surface. Each aperture 6 of the print head 1 is disposed so as to be located at the top of the peripheral surface of the toner carrying roller 14, and the back electrode roller 22 is disposed immediately above the aperture 6.

The control electrodes 4 of the print head 1 are connected to driving elements 8 such as ICs. The driving element 8 applies a voltage of 0 V (OFF) or +30 V (ON) to the control electrode 4 in order to control the toner flow according to an image signal sent from an image signal receiving unit (not shown). It is composed of Here, “OFF” means that the toner 16 does not pass through the aperture 6 and no pixel is formed on the recording medium 20 by the toner 16.
“ON” means that the toner 16 is allowed to pass through the aperture 6 and a pixel is formed on the recording medium 20 by the toner 16. The image signal receiving means (not shown) is connected to an external computer, image reading device, image communication device, or the like. DC power supply (auxiliary control means)
32 is connected, and a voltage lower than the voltage applied to the control electrode 4 is applied. The DC power supply 24 connected to the back electrode roller 22 is configured to apply a voltage of +1 kV to each back electrode roller 22.

FIG. 4 is a perspective view of the toner carrying roller.
On the surface of the toner carrying roller 14, as shown in FIG.
A roller electrode 41 composed of a plurality of elongated electrodes extending in the longitudinal direction is provided. The roller electrode 41 is provided with a contact electrode (voltage applying means) 43 or 45 at each part thereof so that a DC voltage can be applied by the contact electrode 43 or 45. That is, as shown in FIG.
The roller electrode 41a located immediately below the contact electrode 43
As a result, the roller electrode 41b other than immediately below the aperture 6
The contact electrodes 45 allow different voltages to be applied and different potentials to be applied. A DC power supply (voltage applying means) 49 is provided to the contact electrode 43.
Are connected, and the contact electrode 45 is grounded. That is, the roller electrode 41a located immediately below the aperture 6
Is at a DC potential, and the roller electrode 41b at other positions
Is at zero potential.

Next, an image forming operation by the image forming apparatus having the above-described configuration will be described with reference to FIG.
This will be described with reference to FIG. FIG. 5 is an explanatory diagram showing the relaxation of the toner adhesion force on the toner carrying roller 14 when the above-mentioned state is OFF, and FIG. At the start of the image forming operation, first, the supply roller 12 rotates in the direction of the arrow A in FIG. 1 so that the toner 16 contained in the toner case 11 is conveyed by the supply roller 12 toward the toner carrying roller 14. . Toner carrying roller 14
Rotates in the direction of arrow B (FIG. 1), and the toner 16 supplied from the supply roller 12 to the surface of the toner carrying roller 14 is
The print head 1 is transported in the direction. Print head 1
During the conveyance of the toner to the toner layer regulating blade 18,
The toner is charged to a predetermined polarity, in this case, a negative polarity (minus) by the friction with the toner, and a thin and uniform toner layer is formed on the toner carrying roller 14.

Of the roller electrodes 41 provided on the surface of the toner carrying roller 14, the aperture 6 of the print head 1 is
Since the roller electrodes 41b other than the area immediately below are grounded, the toner 16 strongly adheres to the surface of the roller electrode 41b by a physical force such as van der Waals force in addition to a mirror image force due to toner charging. Thus, the toner 16 on the toner carrying roller 14 is transferred toward the print head 1 with the rotation of the toner carrying roller 14.

As shown in FIG. 5, near the area immediately below the aperture 6,
In particular, a negative voltage having the same polarity as the negative polarity (negative), which is the charged polarity of the toner 16, is applied by the DC power supply 49 to the roller electrode 41 a from directly below the aperture 6 to the toner supply side. Further, the print head 1
A positive voltage having a polarity opposite to the polarity of the toner 16 is applied to the auxiliary electrode 31 provided by the DC power supply 32. That is, since the roller electrode 41 a has the same polarity as the toner 16, it exerts a repulsive force on the toner 16, while the auxiliary electrode 31 has a potential opposite to that of the toner 16. Act.
The repulsive force and the attractive force are controlled by voltages applied by the DC power supplies 49 and 32. In particular, the voltage applied to the auxiliary electrode 31 is set lower than the voltage applied to the control voltage 4. As described above, the toner 16 is supplied to the vicinity of the arrangement of the apertures 6 of the print head 1 in a state where the adhesive force between the toner carrying roller 14 and the toner 16 is reduced so as not to fly.

Toner 1 having reduced adhesion as described above
The control voltage applied to the control electrode 4 in the print head 1 supplied with the control signal 6 is controlled as follows. For example, at the time of the above-mentioned ON, +3 is applied to the control electrode 4 from the driving element 8.
When a positive voltage of 0 V is applied, an electric field is generated near the aperture 6 corresponding to the control electrode 4 due to a potential difference between the control electrode 4 and the toner carrying roller 14. Since the negatively charged toner 16 receives an electrostatic force in a direction of higher potential, as shown in FIG.
It is pulled out from above through the aperture 6 to the control electrode 4 side. The extracted toner 16 is applied to the back electrode roller 2.
2 further fly toward the recording medium 20 by an electric field formed between the recording medium 20 and the print head 1 by the high voltage of +1 kV applied to the recording medium 2.
Then, a dot-shaped pixel is formed by depositing on the pixel 0.

At the time of the above-mentioned OFF, the potential of the control electrode 4 is set to 0 V by the driving element 8. As a result, no electric field is generated between the surface of the grounded toner carrying roller 14 and the control electrode 4 so as to move the toner 16 from the toner carrying roller 14 to the control electrode 4, and the toner 16 passes through the aperture 6. I can't. At this time, the control electrode 4
On the other hand, when a negative voltage of −30 V is applied instead of 0 V, the potential of the control electrode 4 is lower than that of the toner carrying roller 14. Is formed, and the passage of the toner 16 through the aperture 6 can be effectively suppressed. Therefore, more OFF
In other words, it is possible to form an image with a high effect, that is, an image with little white background fog.

On the other hand, the recording medium 20 conveyed through the gap between the print head 1 and the back electrode roller 22 is positioned between the rows of the apertures 6 while one row of pixels are formed by the toner 16 on its surface. The data is sent by one pixel in the orthogonal direction. Then, by repeating the above process, a toner image is formed on the entire surface of the recording medium 20. Recording medium 2
The toner image formed on the recording medium 20 is fixed by the heat fixing device 26 (FIG. 1), and the recording medium 20 on which the toner image is fixed is discharged to a discharge tray (not shown).

The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, the roller electrode 41
May be distributed depending on the position of the roller electrode 41. For example, as shown in FIG. 7, a large negative voltage is applied to the roller electrode 41a-1 immediately below the aperture 6 by the power supply 50, and the roller electrodes 41a-2, 41a-3, and 41a-4 are gradually moved away from immediately below the aperture 6. The magnitude of the negative voltage applied to the power supply may be reduced. As a result, the adhesive force of the toner 16 immediately below the aperture 6 becomes the weakest,
The flying of the toner 16 can be effectively controlled by the voltage of the control electrode 4, and at other positions, unnecessary flying can be prevented, and the toner 16 can be effectively transferred.

Further, according to the present invention, the size of the auxiliary electrode 31
The shape and the number are not particularly limited as long as the adhesive force between the toner carrying roller 14 and the toner 16 can be reduced. For example, as shown in FIG.
In addition to 1, the second auxiliary electrode 62 may be provided at a position on the opposite side of the aperture 6 from the toner supply side. When a positive voltage is applied to the second auxiliary electrode 62 by the DC power supply 63, the toner 16 attached to the roller
It is pulled toward the auxiliary electrode 62, and the effect of reducing the adhesive force can be increased. At the same time, a large amount of the toner 16 whose adhesive force has been reduced can be held in a portion directly below the aperture 6. Further, even if the surface of the toner carrying roller 14 is not divided by the fine roller electrode 41, the surface of the toner carrying roller 14 is covered with a uniform electrode, or the toner carrying roller 14 itself is formed of a conductor and the surface is formed. By setting the same potential or the like, the same effect of alleviating the adhesive force can be obtained by maintaining the surface of the toner carrying roller 14 at a negative potential when the toner flies.

In the above embodiment, the print head has a circular aperture. However, the print head may have a rectangular aperture such as a triangle or a quadrangle. It is also possible to use a meshed electrode body as described.
Further, an edge-shaped print head having no aperture as described in JP-A-6-255163 may be used.

[0036]

As described above, according to the image forming apparatus of the first aspect, by controlling the surface potential of the charged body supply means, the adhesive force between the charged body and the charged body supply means is reduced. Since the charged body can be easily separated from the surface of the charged body supply means, the charged body can be smoothly supplied in the charged body flow path. Further, since the charged body can be separated from the charged body supply means without bringing the charged body flow control means and the charged body supply means into contact with each other, the charged body is fixed to the charged body flow control hand or the stepped body supply means. It becomes difficult. Therefore, it is possible to provide an image forming apparatus that can uniformly and stably supply the charged material to all the charged material flow paths and can stably form an image of constant quality without density unevenness.

According to the image forming apparatus of the present invention, since the potential applying means for applying a different voltage to the surface of the charged material supply means depending on the location is provided, the surface potential of the charged material supply means is reduced. It is optimally set according to the supply position, the transfer position, and the flying position of the charged body, so that the adhesion between the charged body supply means and the charged body during holding, transporting, and flying of the charged body can be efficiently reduced.

Furthermore, according to the image forming apparatus of the present invention, since the surface potential of the charged body supply means is set stepwise in the charged body supply direction, the charged material supply position in the charged body supply means. At the transport position, the adhesion between the charged body and the charged body supply means can be increased, and at the flying position, the adhesion between the charged body and the charged body supply means can be reduced. Accordingly, it is possible to smoothly transfer and supply the toner from the charged body supply unit to the charged body flow path while maintaining a state in which the charged body is supplied and transferred.

Further, according to the image forming apparatus of the present invention, it is possible to reduce the adhesive force between the charged body and the charged body supply means only in the vicinity of the charged body flow path by the voltage applying means. The same effect as that of the third aspect can be obtained.

Further, according to the image forming apparatus of the present invention, since the surface potential of the portion immediately below the flow path of the charged body has the same sign as the charge of the charged body, the charged body and the charged body supply means at this position are provided. The adhesive force of the particles is reduced, and the charged body easily flies. This makes it possible to reliably control the flow of the charged body by the charged body flow control means, and to form an image stably on the recording medium.

Further, according to the image forming apparatus of the present invention, by applying a voltage to each of the plurality of long electrodes, it is possible to control the adhesion between the charged body and the charged body supply means. Therefore, with a simple configuration, the adhesive force between the charged body and the charged body supply means is made uniform in the longitudinal direction of the roller, and is different for each area in the rotation direction of the roller (the supply direction of the charged body). It can be set so that it can be changed. Therefore, if the charged material flow paths of the charged material flow control means are arranged so as to be arranged in the longitudinal direction of the roller,
It is also possible to reduce the adhesive force between the charged body and the charged body supply means only at the flight position, and it is possible to uniformly cope with a plurality of charged body flow paths with a simple configuration. Therefore, it is possible to stably form an image of constant quality without density unevenness, and to provide an inexpensive image forming apparatus with a simple configuration.

Further, according to the image forming apparatus of the present invention, the auxiliary control means applies a DC voltage having a sign opposite to that of the charge of the charged body by charging, whereby the charged body is charged. At the flight position and its vicinity, the relaxation of the adhesion between the charged body and the charged body supply means is further enhanced.
As a result, uniform and stable supply of the charged material to all the charged material flow paths can be more reliably achieved, and a uniform quality image can be formed stably without density unevenness. It is possible to provide a simple image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a print head portion provided in the image forming apparatus.

FIG. 3 is a configuration diagram near a print head mounted on the image forming apparatus.

FIG. 4 is a perspective view of a toner carrying roller mounted on the image forming apparatus.

FIG. 5 is an explanatory diagram showing a reduction in toner adhesion force on a toner carrying roller when the image forming apparatus is turned off.

FIG. 6 is an explanatory diagram showing relaxation and flying of toner adhesion on a toner carrying roller when the image forming apparatus is ON.

FIG. 7 is a configuration diagram near a print head mounted on an image forming apparatus according to another embodiment of the present invention.

FIG. 8 is a configuration diagram near a print head mounted on an image forming apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head (charged body flow control means) 4 Control electrode 6 Aperture (charged body flow path) 14 Toner carrying roller (charged body supply means) 16 Toner (charged body) 31 Auxiliary electrode (auxiliary control means) 32 DC power supply (auxiliary) Control means) 41 roller electrode (a plurality of long electrodes) 43 contact electrode (voltage applying means) 45 contact electrode (voltage applying means) 49 DC power supply (voltage applying means)

Claims (7)

[Claims] 1. A charged body flow path through which a charged body passes, charged body flow control means having a control electrode for controlling passage of the charged body in the charged body flow path, and a charged body carried on a surface, A charged body supply means for supplying a charged body to the body flow control means, wherein the passage of the charged body supplied by the charged body supply means in the charged body flow path is controlled by the charged body flow control means. An image forming apparatus that forms an image by flying the charged body against a recording medium located on the opposite side of the charged body supply unit with respect to the charged body flow control unit, wherein the charged body supply unit is The surface potential is variable,
An image forming apparatus characterized in that the charged state of the charged body can be changed by changing the surface potential. 2. The image forming apparatus according to claim 1, further comprising voltage applying means for applying a voltage such that a surface potential of said charged body supply means is different at each surface of said charged body supply means. 3. The image forming apparatus according to claim 2, wherein the voltage applying unit sets the surface charge of the charged body supply unit in a stepwise manner in the charged body supply direction. 4. The image forming apparatus according to claim 2, wherein the voltage applying unit changes the surface charge only in the vicinity of the charged material flow path. 5. The voltage applying means such that a surface potential of a portion immediately below the charged material flow path in the charged material supply means has a potential having the same sign as a charge of a charged material carried by the charged material supply means. The image forming apparatus according to claim 2, wherein a voltage is applied to the image forming apparatus. 6. The charged material supply means includes a charged roller carrying a cylindrical roller member rotatably supported about a central axis of the cylindrical member. The image forming apparatus according to claim 1, further comprising a plurality of long electrodes extending in a longitudinal direction. 7. The charged object flow control means includes an auxiliary control means capable of applying a DC voltage having a sign opposite to that of the electric charge of the charged object on the charged object supply means. The image forming apparatus according to any one of claims 1 to 6, wherein: