JP3242174B2 - Image forming device - Google Patents

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 which can be used for a copying machine, a printer, a plotter, a facsimile and the like.

[0002]

2. Description of the Related Art Conventionally, an image recording apparatus for controlling a toner particle through an aperture by applying an image signal to an electrode having an aperture to obtain an image on a support has been proposed in US Pat. No. 3,689,935. Have been. In this proposal, a reference electrode which is continuous on one side with an insulator layer interposed therebetween and a plurality of control electrodes which are insulated from each other on the other side are provided. Each of the plurality of insulated control electrodes passes through three layers. An aperture electrode as toner flow control means having at least one row of apertures; means for selectively applying a potential between the control electrode and the reference electrode; and toner particles passing through the aperture by the applied potential. And a means for projecting charged particles so as to modulate the flow of particles, and a means for positioning the support in the particle flow path by the relative movement of the support and the aperture electrode body. As a means for supplying charged toner particles to the vicinity of the aperture in this method, Japanese Patent Application No. Hei.
This is proposed in the specification and drawings attached to the application of No. 294587.

[0003]

However, since the black toner used in the above-mentioned conventional image forming apparatus generally contains carbon, it has a volume resistance of 10 volts AC and 10 ¹¹ ohm-cm at 1 kHz. It was as low as centimeters. Therefore, the insulating resistance between the control electrode and the reference electrode decreases due to the toner slightly attached to the aperture or the toner passing through the aperture during printing, and a discharge occurs in the aperture to destroy the aperture electrode body. There was a problem.

[0004] The present invention has been made to solve the problems described above, fly when the image signal is applied
It is an object of the present invention to provide an image forming apparatus in which the toner flow control means is not damaged by the dielectric breakdown caused by the toner.

[0005]

In order to achieve the above object, an image forming apparatus according to the present invention is provided, when an image signal is applied.
The toner in response to the applied image signal
An image is formed on a support by using a toner flow control unit to be attached to a carrier, and the toner is an insulating toner.

Particularly, the volume resistance of the toner is 10
Preferably, the volts are at least 10 ¹⁴ ohm-cm at 1 kilohertz.

[0007]

According to the image forming apparatus of the present invention having the above-described configuration, an image is applied to form an image on a support.
The toner flies according to the image signal and adheres to the support
When an image signal is applied to the toner flow control means, it flies.
Insulation resistance is reduced by toner that is discharged,
-To prevent the flow control means from being destroyed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an image forming apparatus 100 according to an embodiment of the present invention. The aperture electrode body 1
As shown in detail in FIG. 2, the insulating layer 2 has a reference electrode 3 on the toner supply source side and a control electrode 4 on the support side.
Apertures 6 penetrating through the insulating layer 2 and the control electrode 4 are formed in a large number in a line and the width of the support. In FIG. 1, on the left side of the image forming apparatus 100, a cassette 50 for storing the support 10 and a half-moon roller 51 for supplying the support 10 one by one.
And a support supply roller 5 for feeding the support 10 to a downstream portion.
2 and a chute 53 are provided.

In the downstream, on the control electrode side of the aperture electrode body 1, a backing electrode 11 is disposed in contact with the backing of the support transport roller 14, the sensor 57, and the support 10, and each control electrode 4 applies an image signal. Respectively, and are connected to a control voltage driving circuit 8 which generates a voltage. The back electrode 11 is connected to a negative high voltage power supply 12.

On the reference electrode side of the aperture electrode body 1, a toner transport belt 26 is wound between the drive roller 20 and the backup roller 24. On the back side of the aperture surface of the transport belt 26 opposed to the aperture electrode body, an ellipse is provided. Cam roller 2 of cross section
7, a neutralization brush 37 is arranged on the upstream side. These are stored in the toner case 21 together with the toner 22 stored in the vicinity of the supply roller 23 and the support roller 30 having a clearance of 0.1 to 0.4 mm with the toner conveyance belt 26 and the toner conveyance belt 26. I have. The supply roller 23 is a carrier roller 3 such as a sponge.
0 has a surface formed of resin.

The toner 22 has the composition shown in Table 1 below. First, a styrene acrylic resin and oil black are kneaded and pulverized, and then hydrophobic silica is added thereto and stirred at a temperature of several tens of degrees. Manufactured.

Styrene acrylic resin 100 parts by weight Oil black 10 parts by weight Hydrophobic silica 0.5 wf% The volume resistance of the toner 22 is 10 ¹⁴ ohm-cm at 10 volts AC and 1 kHz.

Further downstream, the fixing device 13 and the chute 5
4, a discharge roller 55 and a tray 56 are provided.

Next, the operation of the image forming apparatus configured as described above will be described in detail.

The support 10 accommodated in the cassette 50 is
Rolled out one by one by the half moon roller 51, the shoot 5
3 and is transported to the support transport roller 14 by the support supply roller 52. When the leading end of the support 10 is detected by the sensor 57, the toner transport belt 26 rotates between the backup roller 24 and the drive roller 20 by the rotation of the drive roller 20 in the direction of the arrow, and the supply roller 2
The rotation of the toner 22 in the direction of the arrow 3 causes the toner 22
After being rubbed with the toner and positively charged, the toner is carried on the toner conveying belt 26 by electrostatic application using a high-voltage power supply.

The carried toner is conveyed toward the surface facing the aperture electrode.
The belt 26 is neutralized by the neutralization brush 37 from the back side. Since the cam roller 27 is rotating at the position of the surface facing the aperture electrode, the surface of the transport belt 26 vibrates.
Accordingly, the toner carried on the transport belt 26 receives a force due to the vibration acceleration of the transport belt 26 and is released from the Van der Waals force and the adhesive force such as the electrostatic force with the transport belt 26.

On the other hand, when a negative voltage is applied to the control electrode 4 according to an image signal from a storage means (not shown) at this time,
The aperture 6 of the applied control electrode 4 has an aperture 6
Lines of electric force from the back surface to the front surface are formed, the positively charged toner 22 is pulled out from the back surface of the aperture 6 to the front surface, and furthermore, the flying electric field formed by the back electrode 11 causes It flies upward and is held to form an image area.

At this time, since the toner 22 is an insulating toner having a high volume resistance as described above, even if a considerable amount of the toner 22 passes through the aperture 6, the control electrode 4 and the reference electrode 3 are not connected. The insulation property is maintained, and the dielectric breakdown of the aperture 6 does not occur.

The control electrode 4 in the apertures 6 corresponding to the non-image portion, by the reference electrode 3 is applied to the same potential or a positive voltage, the flying electric field due to the back electrode 11 from the surface to or apertures 6 to the shield By forming lines of electric force toward the reference electrode 3 on the back surface, the passage of the toner 22 through the aperture 6 is suppressed. By repeating this process while transporting the support 10, a toner image is formed on the entire surface of the support 10.

The support having the toner image formed thereon is fixed to the fixing device 1.
3, the image is fixed on the support 10. Further, the sheet is guided by the chute 54 and discharged to the tray 56 by the discharge roller 55.

Next, a second embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, above the aperture electrode body 61, a back electrode roller 82 is provided rotatably on a housing (not shown) so as to transport the support 81 with a gap of 1 mm. ing. A toner supply device 70 is provided below the aperture electrode body 61, and a fixing device 85 is provided at the destination of the support 81.

The toner supply device 70 includes a toner case 71, a toner 76 accommodated therein, a supply roller 73, a toner carrying roller 74 made of aluminum, and a toner layer regulating blade 77. The supply roller 73 and the toner carrying roller 74 are both supported by the toner case 71 so as to be rotatable in the direction of the arrow shown in the figure, and both are arranged in parallel with a slight gap. Further, the toner layer regulating blade 77 is pressed against the toner carrying roller 74.

In the aperture electrode body 61, a row of 100 μm diameter apertures is formed on a 25 μm thick polyimide insulating sheet 62, and a control electrode 63 is formed with a thickness of 1 μm above each aperture. As shown in FIG. 3, the aperture electrode body 61 has a control electrode 63 on the support body 81 side.
And the insulating sheet 62 is disposed so as to be in contact with the toner on the toner carrying roller at the aperture position.

A control voltage application circuit 68 is connected between the control electrode 63 and the toner carrying roller 74. The control voltage application circuit 68 is configured to output 0 or +50 V to the control electrode 63 according to an image signal. A DC power supply 83 is connected between the back electrode roller 82 and the toner carrying roller 74 to apply +1 kV to the back electrode roller.

Next, the operation of the image forming apparatus configured as described above will be described.

The rotation of the toner carrying roller 74 and the supply roller 73 in the direction of the arrow in FIG. 3 causes the toner 76 to rub against the toner carrying roller 74 from the supply roller 73.
It is negatively charged and is carried on a toner carrying roller. The carried toner 76 is thinned by the layer regulating blade 77 and is conveyed toward the vicinity of the aperture electrode body by the rotation of the toner carrying roller 74. Then, the toner on the toner carrying roller 74 is supplied under the aperture while being rubbed by the insulating sheet 62 of the aperture electrode body 61.

Here, the control voltage 63 is applied to the control electrode 63 corresponding to the image portion from the control voltage application circuit 68 in accordance with the image signal.
Is applied. As a result, in the vicinity of the aperture corresponding to the image portion, electric force lines from the control electrode 63 to the toner carrying roller 74 are formed due to the potential difference between the control electrode 63 and the toner carrying roller 74. The negatively charged toner receives an electrostatic force in a direction of higher potential, passes through the aperture 66 from above the toner carrying roller 74, and is drawn out to the control electrode 63 side. The extracted toner flies toward the support by an electric field formed between the support 81 and the aperture electrode 61 by the voltage applied to the back electrode 82, and is deposited on the support to form a pixel. I do.

0 V is applied from the control voltage application circuit 68 to the control electrode corresponding to the non-image portion. As a result, no electric field is formed between the toner carrying roller 74 and the control electrode,
The toner on the toner carrying roller 74 does not receive the electrostatic force and does not pass through the aperture 66.

The support is fed by one pixel in the vertical direction to the aperture row during the pixel formation time of one row. By repeating the above process while the support is transported by the length thereof, a toner image is formed on the entire surface of the support. The formed toner image is fixed on the support by the fixing device 85.

In the image forming apparatus configured as described above, if the insulating toner is used, the toner carrying roller 74 can be used.
The insulation between the electrode and the control electrode 63 is maintained, and the dielectric breakdown of the aperture 66 does not occur.

The present invention is not limited to the embodiment described in detail above, and various modifications can be made without departing from the gist of the present invention.

For example, in the above embodiment, the control voltage of the aperture corresponding to the non-image portion is set to 0 V, but a negative voltage may be applied. In this case, an image with less fog can be obtained. In the embodiment, the aperture electrode body is used as the toner flow control unit.
It is also possible to use an electrode body formed in a stitch shape as described in Japanese Patent Application Publication No. 1-503221.

[0035]

As is clear from the above description,
According to the image forming apparatus of the first aspect of the present invention, since the toner is an insulating toner having a high volume resistance, the toner is formed on the support.
According to the applied image signal to form an image
Toner flow control hand that causes toner to fly and adhere to the support
When a considerable amount of toner passes through the toner flow control means when an image signal is applied to the step , the flying toner
Insulation resistance does not decrease, and toner
It is possible to prevent the control means from being destroyed.

Further, according to the image forming apparatus of the present invention,
If this happens, the toner flow control means will be destroyed due to discharge, etc.
Can be prevented more reliably.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing details of an aperture electrode body used in the image forming apparatus of the present invention.

FIG. 3 is a sectional view showing another embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 aperture electrode body 2 insulating layer 3 reference electrode 4 control electrode 6 aperture 8 control voltage drive circuit 10, 81 support body 22, 76 toner 61 aperture electrode body 62 insulating sheet 63 control electrode 68 control voltage application circuit 74 toner carrying roller

Claims (2)

(57) [Claims] When an image signal is applied, the image signal is applied.
The toner flies according to the image signal and adheres to the support
That by using a toner flow controlling means, an image forming apparatus that forms an image on a support, an image forming apparatus wherein the toner is an insulating toner. 2. The image forming apparatus according to claim 1, wherein the volume resistance of the toner is 10 ¹⁴ ohm-cm at 10 volts AC and 1 kilohertz.