JPH09141919A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a correct image by disposing a control electrode, mounted on the substrate of an electrode body composed of a ceramic material, oppositely to the charged particle supply side of a charged particle supply means thereby attaining an effective control field without applying a high voltage even if the substrate is thick. SOLUTION: The substrate of an aperture electrode body 1 is made of a ceramic material and the control electrode 3 thereof is disposed oppositely to a toner carrying roller 19 while touching each other through a toner layer 14 on same roller. Consequently, the distance between the control electrode 3 and toner carrying roller 19 can be decreased extremely even if the substrate is fairly thick and an effective control field is attained even if the voltage being applied to the control electrode 3 is low. Furthermore, the aperture 4 of the aperture electrode body 1 is positioned accurately with respect to the toner carrying roller 19 or a back pane electrode body 12 because the substrate made of the ceramic material is not flexible and thereby a high quality image can be formed.

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 applicable to a copying machine, a printer, a facsimile, etc.,
In particular, the present invention relates to an image forming apparatus that controls the flight of charged particles such as toner to form an image on a recording sheet.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses of this type, a plurality of openings (apertures) through which toner can pass,
An aperture electrode body having a control electrode for controlling passage of toner through an opening is used.Toner is supplied to the opening by toner supply means, and a voltage is applied to the control electrode to generate an electric field in the opening. There is a type in which an image is formed by controlling the passage of toner through an opening so that the toner is selectively ejected onto an image recording medium such as recording paper. Then, in such an image forming apparatus,
A back electrode is provided on the opposite side of the toner supply means and the aperture electrode body at a predetermined distance from the aperture electrode body, and a predetermined distance is provided between the aperture electrode body and the back electrode. The image recording medium is configured to be transported by the transporting means.

The substrate material for the aperture electrode body may be a plate-shaped insulator, and resin materials such as polyimide and ceramic materials such as alumina and zirconia are used. Among them, when a resin material such as polyimide is used, the material is not brittle, and thus it can be used as a film-shaped thin plate having a thickness of about 25 μm, but it has a drawback that it is easily bent. On the other hand, when a ceramic material is used, since the material is brittle, a certain thickness of 140 to 15 is used.
It needs to be about 0 μm.

[0004]

However, in general, since the aperture electrode body controls the toner flow, its control electrode surface is arranged on the side opposite to the toner supply means, that is, on the side facing the image recording medium. In such an arrangement, the ceramic material is used as the material of the substrate, and the distance to the toner supply means increases as the thickness of the substrate increases. If applied to the control electrode, the electric field strength inside the aperture becomes weak, and an effective control electric field cannot be obtained. Therefore,
If a high voltage is applied to increase the electric field strength, the IC for driving the control electrode becomes expensive. The present invention has been made to solve the above-mentioned problems, and when a ceramic material is used as the material of the aperture electrode body, a high voltage is applied to the control electrode even if the thickness of the substrate is increased to some extent. An object of the present invention is to provide an image forming apparatus that can obtain an effective control electric field without applying the voltage and can form an appropriate image.

[0005]

According to another aspect of the present invention, there is provided an image forming apparatus, wherein a plurality of openings are formed in at least one row, and a plurality of control electrodes corresponding to the openings are provided. An electrode body having the same, a charged particle supply means for supplying charged particles to the opening of the electrode body, and a conveyance for conveying an image recording medium such as recording paper to the opposite side of the charged particle supply means with the electrode body interposed therebetween. And a means for controlling the voltage applied to each control electrode of the electrode body to selectively fly the charged particles from the charged particle supply means through the opening onto the image recording medium to form an image. In the image forming apparatus, the electrode body has a substrate made of a ceramic material, and the control electrode provided on the substrate is arranged so as to face the charged particle supply side by the charged particle supply means.

In the above structure, the substrate of the electrode body is made of a ceramic material, and the control electrode is arranged so as to face the charged particle supply side even if the thickness of the substrate is increased to some extent. The distance from the particle supply means can be made small, so that an effective control electric field can be obtained without particularly increasing the voltage applied to the control electrode.

The image forming apparatus according to the second aspect of the invention is
In addition to the above configuration, a back electrode body is provided on the opposite side of the charged particle supply means and the electrode body with a predetermined distance from the electrode body. It is arranged so as to be in contact with the supply means through charged particles.

In the above structure, since the electrode body and the charged particle supply means are disposed so as to be in contact with each other through the charged particles, the electrode body and the charged particle supply means are in close proximity to each other, and the above-mentioned operation is achieved. It is even more prominent. Further, since the electrode body made of a ceramic material is hard to bend, it becomes easy to set a predetermined distance between the electrode body and the charged particle supply means or the back electrode body.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view of the image forming apparatus, FIG. 2 is a perspective view of an aperture electrode body used in the apparatus, and FIG. 3 is a diagram showing a positional relationship between the aperture electrode body and a toner carrying roller. In FIG. 1, the image forming apparatus 10 is provided with a toner supply device 11 (charged particle supply means) in which a toner 14 that is a charged particle is housed. The toner supply device 11 is opposed to the opening (aperture). And an aperture electrode body 1 as an electrode array for controlling the passage of the toner 14 through the apertures.
A back electrode plate 12 is provided on the opposite side of the toner supply device 11 with the aperture electrode body 1 interposed therebetween with a distance of about 0.5 to 1 mm from the aperture electrode body 1.

Further, in the image forming apparatus 10, a pair of transport rollers 1 as a transport means for transporting an image recording medium such as recording paper into a gap between the aperture electrode body 1 and the back electrode plate 12.
3 is provided. By the rotation of the carrying roller 13 in the direction of arrow D, the image recording medium 15 is inserted and carried in the direction of arrow C, and a toner image is formed on the image recording medium 15. Further, a fixing device 16 for fixing an image on the image recording medium 15 is arranged on the conveying direction of the image recording medium 15. The fixing device 16 is a thermal fixing system which is composed of a pressure roller 17 having a surface layer of silicon rubber and a heat roller 18 having a halogen heater therein. The image recording medium 15 is carried in between the aperture electrode body 1 and the back electrode body 12 so as to be in contact with the back electrode body 12 and with a predetermined distance from the surface of the aperture electrode body 1. .

The toner supply device 11 is provided with a toner case 20 as a main body frame which also serves as a housing of the entire toner supply device 11, and the toner 1
A cylindrical toner carrying roller 19 carrying 4 and delivering it to the aperture electrode body 1 is rotatably supported in the toner case 20 in the direction of arrow B. Behind the toner carrying roller 19, a cylindrical supply roller 21 for supplying the toner 14 to the roller 19 is provided. In the toner case 20, the toner 14 carried by the toner carrying roller 19 is provided above the toner carrying roller 19.
The toner layer regulating blade 22 is provided for adjusting the amount of the toner to be uniform on the roller surface of the toner carrying roller 19 and for uniformly charging the toner 14.

The aperture electrode body 1 will be described with reference to FIG. The aperture electrode body 1 includes an electrode substrate 2 made of a ceramic material, and a plurality of openings (apertures) 4 are formed on the electrode substrate 2 in parallel in the longitudinal direction of the aperture electrode body 1 and each aperture 4 is formed. A control electrode 3 made of copper foil is provided on the base plate, and thus an electrode array 5 is formed.

Next, the positional relationship between the aperture electrode body 1 and the toner carrying roller 19 will be described with reference to FIG.
The aperture electrode body 1 is arranged so that the center line 30 of each aperture 4 passes through the uppermost portion of the peripheral surface of the toner carrying roller 19 and the central axis 32 of the toner carrying roller 19. Further, the surface on which the control electrode 3 is provided is arranged so as to be in contact with the toner carrying roller 19 via the toner layer supplied to the surface thereof. With this configuration, the respective apertures 4 are evenly arranged on the left and right with respect to the uppermost part of the peripheral surface of the toner carrying roller 19, so that the distribution of the toner 14 passing through the respective apertures 4 is made uniform throughout the aperture. Can be Further, since the wall surface of the aperture 4 and the flying direction of the toner 14 are parallel to each other, the toner can be stably jetted, and uneven density of the toner can be suppressed as much as possible.

Next, the operation of the image forming apparatus 10 configured as described above will be described with reference to FIGS. 1 to 3. When a voltage of +30 V is applied from the data control circuit 24 to the aperture electrode body 1 in response to an image signal sent from an image signal receiving means (not shown), the control electrode 3 is applied to the aperture 4 to which the voltage is applied. A line of electric force directed toward the toner carrying roller 19 is formed, whereby the negatively charged toner 14 receives an electrostatic force in the direction of high potential,
The toner is passed from the toner carrying roller 19 through the aperture 4 to the control electrode 3 side. The drawn toner 14 is
By the electric field formed between the image recording medium 15 and the aperture electrode body 1 by the voltage of +1 KV applied to the back electrode plate 12 by the back voltage application circuit 23, the image recording medium 1
5 flies toward 5, and deposits on the image recording medium 15 to form pixels.

Since a voltage of -30 V is applied from the data control circuit 24 to the control electrode 3 corresponding to the non-image portion, an electric field is not formed between the toner carrying roller 19 and the control electrode 3. As a result of the toner carrying roller 19 not receiving an electrostatic force, the toner 14 does not pass through the aperture 4. Therefore, no pixel is formed in the portion of the image recording medium 15 facing the control electrode 3.

When one row of pixels is formed by the toner 14 on the surface of the image recording medium 15, the carrying roller 13 then carries one pixel in the direction perpendicular to the row of the apertures 4. Thus, the toner image is formed on the entire surface of the image recording medium 15 by repeating the above-described image forming process. After that, the toner image formed on the image recording medium 15 is fixed by the fixing device 16.

In the above embodiment, the substrate of the aperture electrode body 1 is made of a ceramic material, the control electrode 3 thereof faces the toner carrying roller 19, and the control electrode 3 and the toner carrying roller 19 are on the same roller. Since they are arranged so as to be in contact with each other via the layer of the toner 14, the control electrode 3 and the toner carrying roller 19 are formed even if the thickness of the substrate is increased to some extent.
Can be made extremely small, and therefore an effective control electric field can be obtained even when the voltage applied to the control electrode 3 is low. Further, since the substrate made of a ceramic material is difficult to bend, the position of the aperture 4 of the aperture electrode body 1 with respect to the toner carrying roller 19 or the back electrode body 12 becomes accurate, which enables high-quality image formation. .

The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, the back electrode plate 1
Instead of this, 2 may use a rotatable back roller. Further, the control electrode 3 is in contact with the toner carrying roller 19 via the toner 14, but there is a problem if the control electrode 3 is in direct contact and short-circuited without the toner 14.
Therefore, in order to prevent such a situation, the surface of the control electrode 3 may be coated with an insulating film.

[0019]

As described above, according to the image forming apparatus of the first aspect of the present invention, when the substrate of the electrode body is made of a ceramic material, even if the thickness of the substrate is increased to some extent, the control electrode is charged particles. Since it is arranged so as to face the supply side, the distance between the control electrode and the charged particle supply means can be made small, and therefore an effective control electric field can be obtained without applying a high voltage to the control electrode, and an appropriate control field can be obtained. With image formation,
Since a high-voltage drive circuit or the like is not required, cost increase can be suppressed.

According to the image forming apparatus of the second aspect of the invention, the electrode body is arranged so as to contact the charged particle supply means through the charged particles, and the distance between the electrode body and the charged particle supply means is close. Therefore, the above-mentioned effects can be obtained more remarkably, and since the electrode body made of a ceramic material is difficult to bend, the electrode body can be accurately positioned with respect to the charged particle supply means or the back electrode body, and therefore the high It is possible to form a high quality image.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a part of an aperture electrode body used in the device.

FIG. 3 is a diagram showing an arrangement relationship between an aperture electrode body and a toner carrying roller.

[Explanation of symbols]

 1 Aperture Electrode Body 2 Electrode Substrate 3 Control Electrode 4 Opening (Aperture) 10 Image Forming Device 11 Toner Supply Device 12 Back Electrode Plate 14 Toner 15 Image Recording Medium

Claims (2)

[Claims] 1. An electrode body having a plurality of openings arranged in at least one row and having a plurality of control electrodes corresponding to the openings, and a charge for supplying charged particles to the openings of the electrode body. A particle supply unit and a conveyance unit that conveys an image recording medium such as recording paper to the opposite side of the charged particle supply unit with the electrode body interposed therebetween, and control the voltage applied to each control electrode of the electrode body. In the image forming apparatus, the charged particles are caused to pass through the opening from the charged particle supply means and selectively fly onto the image recording medium to form an image, wherein the electrode body has a substrate made of a ceramic material. Consists of,
An image forming apparatus, wherein the control electrode provided on the substrate is arranged so as to face a charged particle supply side by the charged particle supply means. 2. A back electrode body disposed on the opposite side of the charged particle supply means and the electrode body with a predetermined distance from the electrode body, wherein the electrode body has a control electrode. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged so as to be in contact with the charged particle supply unit via charged particles.