JPH07314765A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device, with which recording with high image quality can be obtained, by a method wherein grooves having the width finer than that of a controlling part are formed in the conveying direction of the toner on the surface on the toner carrier side of the controlling means of the toner flow. CONSTITUTION:Each aperture 6 is so arranged as to pass its center line 30 through both the uppermost part of the peripheral surface of a toner carrying roller 14 and the center axis 32 of the toner carrying roller 14. Further, the direction, to which each groove guide part 5 extends, coincides with the conveying direction of toner conveyed by the toner carrying roller 14. Since the respective apertures 6 are evenly arranged right and left about the uppermost part of the peripheral surface of the toner carrying roller 14, the distribution of the toners passing through the respective apertures can be made uniform over the whole range in the apertures. Furthermore, since the cell surface of the aperture 6 and the flying dirction of toner are parallel to each other, stable flying of the toner is realized.

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 in copying machines, printers, plotters, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses, an electrode having a plurality of openings (hereinafter referred to as apertures) is used, and a voltage is applied to the electrode based on image data. U.S. Pat. No. 3,689,935 discloses controlling toner particles so that they can pass through the aperture and forming an image on a support by the toner particles that have passed.

This image forming apparatus comprises a flat plate made of an insulating material, a continuous reference electrode formed on one surface of the flat plate, and a plurality of control electrodes insulated from each other formed on the other surface. , An aperture electrode body having at least one row of apertures formed through each of the control electrodes, and a means for selectively applying a potential between the reference electrode and the control electrode. A means for supplying the charged toner particles so that the flow of the toner particles passing through the aperture is modulated by the electric potential, and a means for relatively moving the support and the aperture electrode body to position the support in the particle flow path. It consists of and.

Also, for example, US Pat. No. 4,743,926.
Nos. 4,755,837, 4,780,733, and 4,847,796 disclose an image forming apparatus in which an aperture electrode body is arranged with a control electrode on the support side and a reference electrode on the toner supply side. There is.

In contrast, US Pat. No. 4,912,489
In the specification of the above U.S. Pat. It is described that it can be suppressed to about 1/4 as compared with the image forming apparatus.

Here, the "off" means a time when the toner particles are not attached to the support, that is, a time when a blank portion of an image is formed, and conversely, "on" means that the support is on the support. It means a time point when a toner image is formed on.

[0007]

However, it is difficult for the conventional image forming apparatus as described above to obtain a sufficient image quality. As a result of further study on the problem, it was found that the required amount of toner was not always supplied directly under the aperture of the aperture electrode body. That is, since the toner flow supplied to the aperture electrode body may pass out of the area directly below the aperture of the aperture electrode body,
Even if the electric field was controlled, the required toner was not present immediately below the aperture of the aperture electrode body, and high quality recording could not be obtained. Further, especially when the toner flow passes out of the area directly below the aperture of the aperture electrode body, toner that does not pass under the aperture passes as it is without being used, and therefore does not contribute to printing at all. .

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus capable of high-quality recording.

[0009]

In order to achieve this object, an image forming apparatus of the present invention comprises a toner carrier for supplying charged toner, the toner carrier is disposed via the toner, and an electric field is applied. Is an image forming apparatus including a toner flow control unit having a plurality of control units for controlling the flow of toner by means of a toner flow control unit, and a rear electrode provided on the opposite side of the toner carrier from the toner flow control unit. Then, the toner carrier is arranged so as to contact the toner flow controller in the controller, and at least the width smaller than or equal to the width of the controller is provided on the toner carrier side surface of the toner controller. The groove is formed in the toner conveying direction.

[0010]

In the image forming apparatus of the present invention having the above-mentioned structure, the toner carried on the toner carrying member is directed to the portion opposed to the control section of the toner flow control means in the toner conveying direction without coming off immediately below the control section. Is guided to flow evenly. Therefore, it is possible to always supply the required amount of toner that can be used for recording, so that electric field control can be reliably performed and high quality recording can be performed.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an outline of an image forming apparatus embodying the present invention. A gap of 1 mm is provided above an aperture electrode body 1 as a toner flow control means to serve as a counter electrode. A cylindrical back electrode roller 22 is rotatably arranged on a chassis (not shown), and is configured to be able to convey the support 20 inserted into the gap. Further, a toner supply device 10 is arranged below the aperture electrode body 1 along the longitudinal direction of the aperture electrode body 1, and further, a support body conveyed by the back electrode roller 22. A fixing device 26 is disposed at the destination of the movement of 20.

Next, the respective components will be described in detail. In the toner supply device 10, the toner case 11 also serving as a housing of the entire device, the toner 16 housed in the toner case 11, and the supply roller 12 are provided. A toner carrier roller 14 as a toner carrier, and a toner layer regulating blade 18 as a toner layer regulating means. Here, the toner carrying roller 14 carries the toner 16 and conveys it toward the aperture electrode body 1, and the supply roller 12 supplies the toner 16 to the toner carrying roller 14.

The supply roller 12 and the toner carrying roller 14 are rotatably supported by the toner case 11 in the direction of the arrow shown in FIG. Further, the toner layer regulating blade 18
Is for adjusting the amount of the toner 16 carried on the toner carrying roller 14 to be uniform on the roller surface and for uniformly charging the toner 16, and is pressed against the toner carrying roller 14. .

As shown in FIG. 2, the aperture electrode body 1 includes a polyimide insulating sheet 2 having a thickness of 25 μm and a diameter of 1 mm.
A plurality of apertures 6 having a size of 00 μm are formed in one row, and a control electrode 4 having a thickness of 1 μm is formed for each aperture 6 on the upper surface. The control unit of the present invention is configured by the apertures 6 and the control electrodes 4. To be done. As shown in FIG. 1, the aperture electrode body 1 is pressed against the toner carrying roller 14 at the aperture position of the insulating sheet 2 with the control electrode 4 facing the support body 20 side.

Further, the configuration of the aperture electrode body 1 of this embodiment will be described in detail with reference to FIGS. 4 and 5. FIG. 4 is a bottom view of the aperture electrode body, and FIG. 5 is a view of B- of FIG.
It is a B line sectional view.

Of the insulating sheet 2 of the aperture electrode body 1,
A groove guide portion 5 as a groove of the present invention is provided on the entire surface opposite to the surface on which the control electrode 4 is provided. The groove guide portion 5 has a width that is at least smaller than the diameter of the aperture 6 and has a so-called fine groove shape that guides toner to the aperture 6.
It extends in the same direction as the toner carrying direction of the toner carrying roller 14.

Further, the groove guide portion 5 may be basically made of any material. However, when it is made of the same material as the insulating sheet, the sliding characteristics are different from those of the insulating sheet 2. Since it does not change, the groove guide portion 5 and the insulating sheet 2 may be formed integrally or separately, but if they are made of the same material, they are preferably formed integrally. .

Now, the positional relationship between the aperture 6 of the aperture electrode body 1 and the toner carrying roller 14 will be described in detail. As shown in FIG. 3, each center line 30 of each aperture 6 has a toner carrying roller 14. Is arranged so as to pass through the uppermost portion of the peripheral surface of the toner carrier roller 14 and the central shaft 32 of the toner carrying roller 14, and the direction in which the groove guide portion 5 extends is the toner carrying direction of the toner carrying roller 14 (the carrying of the support 20). Direction). According to this, the respective apertures 6 are evenly arranged on the left and right with respect to the uppermost portion of the peripheral surface of the toner carrying roller 14, so that the distribution of the toner 16 passing through the apertures 6 is distributed over the entire area of the aperture. Can be uniform. Further, since the wall surface of the aperture 6 and the flying direction of the toner 16 are parallel to each other, it is possible to stably fly the toner.

Further, the aperture electrode body 1 itself is arranged with respect to the toner carrying roller 14 as shown in FIG.
It is pressed so that it bends to the left and right about the same angle. As a result, the contact area between the aperture electrode body 1 and the toner carrying roller 14 can be increased, and the lower periphery of the aperture 6 can be pressed uniformly to the left and right, so that uneven toner concentration is minimized. Can be suppressed.

A control voltage application circuit 8 as a control voltage application means is connected between the control electrode 4 and the toner carrying roller 14. This control voltage applying circuit 8
0V to the control electrode 4 based on the image signal, or +
It is configured to apply a voltage of 50V.

Further, a DC power supply 24 is connected between the back electrode roller 22 and the toner carrying roller 14, and this DC power supply can apply a voltage of +1 kV to the back electrode roller 22. It is like this.

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

First, by rotating the toner carrying roller 14 and the supply roller 12 in the direction of the arrow shown in FIG. 1, the toner 16 sent from the supply roller 12 is rubbed against the toner carrying roller 14 and is negatively charged. The toner is carried on the toner carrying roller 14. The carried toner 16 is thinned and charged by the layer regulation blade 18, and then is conveyed toward the aperture electrode body 1 by the rotation of the toner carrying roller 14. Then, the toner on the toner carrying roller 14 is supplied under the aperture 6 while being rubbed by the insulating sheet 2 of the aperture electrode body 1.

At this time, since the groove guide portion 5 is provided in the insulating sheet 2 of the aperture electrode body 1, the toner 16 carried by the toner carrying roller 14 and conveyed is in the rotating direction of the toner carrying roller 14. Then, it goes straight to and is supplied at a constant amount just below the aperture 6. That is, the toner 16 carried on the toner carrying roller 14 approaches the aperture 6 while being rubbed by the aperture electrode body 1, but at this time, the toner carrying not facing each aperture 6 is accompanied by the rotation of the toner carrying roller 14. The toner 16 carried on the roller 14 is
The portion which is guided by the groove guide portion 5 and faces the aperture 6 is conveyed in a straight line in the rotation direction of the toner carrying roller 14, whereby a constant amount of toner 16 is constantly supplied to the aperture 6.

Here, in accordance with the image signal, the control voltage applying circuit 8 adds + to the control electrode 4 corresponding to the image portion.
A voltage of 50V is applied. As a result, a line of electric force directed from the control electrode 4 to the toner carrying roller 14 is formed in the vicinity of the aperture 6 corresponding to the image portion due to the potential difference between the control electrode 4 and the toner carrying roller 14. As a result, the negatively charged toner receives an electrostatic force in the direction of higher electric potential, passes through the aperture 6 from the toner carrying roller 14 and is drawn to the control electrode 4 side. The extracted toner 16 further flies toward the support 20 due to the electric field formed between the support 20 and the aperture electrode body 1 by the voltage applied to the back electrode 22, and the toner 16 on the support 20 rises. To form pixels.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4 corresponding to the non-image portion.
As a result, since no electric field is formed between the toner carrying roller 14 and the control electrode 4, the toner carrying roller 1
The toner 16 on 4 does not pass through the aperture 6 because it is not subjected to electrostatic force.

Further, the support 20 is fed by one pixel in the direction perpendicular to the aperture row while the toner 16 forms one row of pixels on the surface thereof. Then, the toner image is formed on the entire surface of the support 20 by repeating the above process. Then, the formed toner image is fixed on the support 20 by the fixing device 26.

By the steps as described above, the toner is recorded on the image receiving body. At this time, the aperture 6 is constantly moved straight from the upstream side to the downstream side in a fixed direction to supply a constant amount of toner.
Therefore, the control of the toner by the control electrode 4 can be reliably performed, and good recording can be performed.

If an insulating toner is used in the image forming apparatus having the above-described structure, the toner carrying roller 14 is used.
The insulation between the control electrode 4 and the control electrode 4 is maintained, and the aperture 6 does not cause dielectric breakdown.

In the above process, the control electric field generated by the control electrode 4 is formed between the control electrode 4 and the inside of the aperture 6, and between the aperture 6 and the toner carrying surface of the toner carrying roller 14 which faces the aperture 6. Toner 1
Since the control electric field can be directly applied to 6, the control efficiency is good.

Even if a part of the supplied toner 16 receives mechanical force by sliding with the aperture electrode body 1 and enters the aperture 6 corresponding to the non-image portion, the inside of the aperture 6 Since it can be controlled so as not to pass through the aperture 6 by the electric field, the toner controllability is good.

Further, since the toner carrying roller 14 and the aperture electrode body 1 are opposed to each other with the toner layer interposed therebetween, they can be arranged at a relatively short distance, so that the control voltage can be lowered and an inexpensive drive element can be provided. Can be used.

In addition, the insulating sheet 2 of the aperture electrode body 1
Is directed toward the toner carrying roller 14 side, so that the toner
Even if 6 is not present, the control electrode 4 and the toner carrying roller 14 do not come into contact with each other and electrically short-circuit, and the drive element is not destroyed.

Further, since the aperture electrode body 1 and the toner 16 on the toner carrying roller 14 are in contact with each other at the entrance portion of the aperture 6, the toner 16 accumulated at the entrance portion of the aperture 6 is not supported. Since the toner 16 is pushed away by the toner sequentially supplied, the toner 16 does not accumulate and bridge to block the aperture 6.

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

For example, although the control voltage of the aperture corresponding to the non-image portion is set to 0V in the above embodiment, it may be a negative voltage. In this case, an image with less fogging can be obtained. Further, in the above embodiment, the aperture electrode body is used as the toner flow control means, but it is also possible to use, for example, a knitted electrode body as described in the specification of US Pat. No. 5,036,341.

Further, in the above embodiment, the groove guide portion 5 is provided on the entire upstream and downstream of the aperture, but the groove guide portion 5a may be arranged only on the upstream side of the aperture as shown in FIG. 6 and 7 are views showing a second embodiment of the present invention, FIG. 6 is a bottom view of the aperture electrode body, and FIG. 7 is a C of FIG.
It is a sectional view taken along the line C, and the members having the same functions as those in the first embodiment will be described with the same reference numerals.

That is, in this embodiment, the groove guide portion 5a is provided on the insulating sheet 2 of the aperture electrode body 1 only on the upstream side of the aperture.

In this embodiment, the groove guide portion 5 is provided over the entire area of the aperture in the longitudinal direction, but the groove guide portion 5b may be arranged only in the aperture hole width as shown in FIG. still,
8 and 9 are views showing a third embodiment of the present invention,
FIG. 8 is a bottom view of the aperture electrode body, and FIG. 9 is a cross-sectional view taken along the line DD of FIG. 8. The members having the same functions as those in the first embodiment are designated by the same reference numerals and described. To do.

That is, in this embodiment, the groove guide portion 5b is provided only on the insulating sheet 2 of the aperture electrode body 1 within the range of the aperture width.

Further, in this embodiment, the groove guide portion 5 is provided on the entire upstream and downstream of the aperture, but the groove guide portion 5c may be arranged only on the upstream side of the aperture hole width portion as shown in FIG. still,
10 and 11 are views showing a fourth embodiment of the present invention, and FIG. 10 is a bottom view of the aperture electrode body.
FIG. 11 is a cross-sectional view taken along the line EE of FIG. 10, and members having the same functions as those of the first embodiment will be described with the same reference numerals.

That is, in this embodiment, the groove guide portion 5c having the same size as the aperture width is provided only on the upstream side on the insulating sheet 2 of the aperture electrode body 1.

In this embodiment, the groove of the groove guide portion 5 is
Although provided in the moving direction of the toner carrier, the groove guide portion 5d may be obliquely arranged as shown in FIG. Incidentally, FIG. 12 and FIG.
3 is a view showing a fifth embodiment of the present invention, FIG. 12 is a bottom view of an aperture electrode pair, and FIG.
It is a -F line sectional view, and the member which shows the same function as a 1st example is given the same numerals, and is explained.

That is, in this embodiment, the groove guide portion 5d oblique to the toner conveying direction is provided on the insulating sheet 2 of the aperture electrode body 1.

Further, in this embodiment, the groove of the groove guide portion 5 is
Although it has a semi-cylindrical groove shape, a V-shaped groove guide portion 5e may be arranged as shown in FIG. In addition, FIG.
It is a figure which shows the 6th Example of this invention, The same code | symbol is attached | subjected and demonstrated to the member which exhibits the same function as 1st Example.

That is, in this embodiment, the V-shaped groove guide portion 5 is formed on the insulating sheet 2 of the aperture electrode body 1.
e is provided.

Further, in this embodiment, the groove of the groove guide portion 5 is
Although it has a semi-cylindrical groove shape, an angular groove guide portion 5f may be arranged as shown in FIG. Note that FIG. 15 is a diagram showing a seventh embodiment of the present invention, and members having the same functions as those of the first embodiment will be described with the same reference numerals.

That is, in this embodiment, the rectangular groove guide portion 5f is provided on the insulating sheet 2 of the aperture electrode body 1.

Further, in this embodiment, the groove guide portion 5 is provided by connecting a plurality of grooves in succession. However, as shown in FIG. 16, the groove guide portions 5g may be arranged with the grooves separated from each other. Note that FIG. 16 is a diagram showing an eighth embodiment of the present invention, and members having the same functions as those of the first embodiment will be described with the same reference numerals.

That is, in this embodiment, on the insulating sheet 2 of the aperture electrode body 1, there is provided a groove guide portion 5g composed of a plurality of grooves spaced apart from each other.

[0052]

As is apparent from the above description, in the image forming apparatus of the present invention, the toner carrier is arranged in contact with the toner flow control means in the control portion, and the toner flow control means is arranged. Since a groove having a width smaller than or equal to the width of the control section is formed in the toner carrier direction on the surface of the toner carrier, the toner is supplied straight below the control section of the aperture electrode body in a fixed direction and supplied in a constant amount. It
As a result, it is possible to provide an image forming apparatus capable of high quality recording.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment embodying the configuration of an image forming apparatus of the present invention.

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

FIG. 3 is a diagram schematically showing a configuration of an aperture electrode body and a toner carrying roller used in the image forming apparatus of the present invention.

FIG. 4 is a bottom view showing a configuration of an aperture electrode.

FIG. 5 is a cross-sectional view showing a configuration of an aperture electrode.

FIG. 6 is a bottom view of an aperture electrode body showing a second embodiment of the present invention.

7 is a cross-sectional view taken along the line BB of FIG.

FIG. 8 is a bottom view of an aperture electrode body showing a third embodiment of the present invention.

9 is a cross-sectional view taken along the line CC of FIG.

FIG. 10 is a bottom view of an aperture electrode body showing a fourth embodiment of the present invention.

11 is a cross-sectional view taken along the line DD of FIG.

FIG. 12 is a bottom view of an aperture electrode body showing a fifth embodiment of the present invention.

13 is a cross-sectional view taken along the line EE of FIG.

FIG. 14 is a sectional view of an aperture electrode body showing a sixth embodiment of the present invention.

FIG. 15 is a sectional view of an aperture electrode body showing a seventh embodiment of the present invention.

FIG. 16 is a sectional view of an aperture electrode body showing an eighth embodiment of the present invention.

[Explanation of symbols]

 1 Aperture Electrode Body 2 Insulating Sheet 4 Control Electrode 5 Groove Guide 6 Aperture 8 Control Voltage Application Circuit 14 Toner Carrier Roller 22 Back Electrode Roller 24 DC Power Supply

Claims (4)

[Claims] 1. A toner carrier for supplying charged toner, and a toner flow control means arranged with the toner carrier interposed therebetween and having a plurality of control units for controlling the toner flow by an electric field. In the image forming apparatus composed of the toner carrier and the back electrode provided on the opposite side of the toner flow control means, the toner carrier is brought into contact with the toner flow control means in the control section. And a groove having a width at least narrower than the width of the control portion is formed on the surface of the toner flow control unit on the side of the toner carrier in the toner conveying direction. 2. A toner carrier for supplying charged toner, and a toner flow controller having a plurality of control units arranged with the toner interposed therebetween and controlling the toner flow by an electric field. In the image forming apparatus composed of the toner carrier and the back electrode provided on the opposite side of the toner flow control means, the toner carrier is brought into contact with the toner flow control means in the control section. And a groove having the same width as the width of the controller is formed in the toner transport direction on the surface of the toner flow control means on the side of the toner carrier. 3. The groove portion is arranged on the surface of the toner flow control means on the toner carrier side, and is arranged on the upstream and downstream sides of the control portion.
The toner carried on the toner carrier at a position not facing the control unit is guided straight to the portion facing the control unit from upstream to downstream, and is uniformly guided. The image forming apparatus described. 4. The groove portion is disposed on the toner carrier side of the toner flow control means, on the upstream side of the controller, and holds the toner carried on the toner carrier at a position not facing the controller. The image forming apparatus according to claim 1 or 2, wherein the image forming apparatus guides straight from an upstream side to a downstream side of a portion facing the control unit and uniformly guides the portion.