JPH06297753A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus eliminating the irregulality of the supply amt. of toner to a toner support due to sliding to eliminate density irregularity from a recording image and capable of forming an image of high image quality. CONSTITUTION:A toner support roller 14 is constituted by forming toner support spacers 17 made of a resin on a metal roller in a strip like form. Four toner support spacers 17 are formed on the roller at an equal interval in the longitudinal direction of the roller and the surfaces of the metal roller between the toner support spacers 17 form toner support parts. An aperture electrode 1 is constituted by arranging many apertures 6 to an insulating sheet 2 at an equal interval in one row so as to pierce the insulating sheet 2 and forming control electrodes 4 to the opening peripheral edges of the respective apertures 6. The aperture electrode 1 is arranged in contact with the toner support spacers 17 so as to most approach the toner on the toner support part 18 at the positions of the apertures 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
The present invention relates to an image forming apparatus that can be used for plotters, facsimiles, and the like.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus for obtaining an image on a support by controlling the passage of toner particles through an aperture by applying an image signal to an electrode having an aperture has been proposed in US Pat. No. 3,689,935. Has been done.

The image forming apparatus described in US Pat. No. 3,689,935 is composed of a shield electrode which is continuous on one side with a layer of an insulator interposed therebetween and a plurality of control electrodes which are insulated from each other on the other side. And is formed through three layers for each insulated plurality of control electrodes and at least 1
An aperture electrode body having apertures arranged in rows, a means for selectively applying a potential between the control electrode and the shield electrode, a means for supplying charged toner particles to the aperture of the aperture electrode body, and a support It is arranged on the opposite side of the aperture electrode body, and comprises a back electrode to which a high voltage is applied, and a means for moving the support body relative to the aperture electrode body to position the support body in the particle flow path. Has been done.

However, according to this apparatus, the toner particles clog the apertures to deteriorate the recording quality, and the recording speed cannot be increased so much.

The applicant further studied, and as described in the application of Japanese Patent Application No. 4-254494, recording was carried out by arranging the carrier holding the toner and the recording electrode in contact with each other. An image recording apparatus that can greatly improve the characteristics is also proposed. According to this device,
Since the recording electrodes are not clogged, the image quality is remarkably improved, and it has become possible to reduce the size and cost of the image recording apparatus.

[0006]

However, in this conventional image forming apparatus, since the carrier holding the toner and the recording electrode are arranged in contact with each other, the toner carrier supplied to the recording electrode is not supported. There is a problem that unevenness in carrying occurs due to the sliding of the toner of (1) before being conveyed under the aperture, and unevenness occurs in a recorded image.

The present invention has been made to solve the above-mentioned problems, and it is possible to eliminate unevenness in the amount of toner supplied on the toner carrier due to sliding, and as a result, it is possible to eliminate unevenness in density from a recorded image. It is therefore an object of the present invention to provide an image forming apparatus capable of forming a high quality image.

[0008]

In order to achieve this object, an image forming apparatus of the present invention comprises a toner flow control means provided with a toner flow control section, and a toner for supplying a charged toner to the toner flow control means. The carrier and the toner carrier are composed of a back electrode provided on the opposite side of the toner flow control means, and control the passage of the toner supplied by the toner carrier through the toner flow control unit to control the back surface. An image forming apparatus for forming an image on a support member supported on electrodes, wherein a gap is provided between the toner carrying member and the toner flow controlling unit. It is characterized by arranging a spacer portion for forming the.

Further, the toner carrying member may be composed of a toner carrying portion carrying the toner in a layer form and the spacer portion.

[0010]

According to the image forming apparatus of the present invention having the above-mentioned structure, the toner is carried on the toner carrying portion of the toner carrying member, and the spacer portion is provided between the toner carrying portion and the toner flow control means. The toner is supplied to the toner flow control unit through the generated gap. At this time, the toner on the toner carrier is not brought into pressure contact with the toner flow control means by the spacer portion, so that unevenness in carrying does not occur.

[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 according to the present invention, in which a columnar cylinder serving as a back electrode having a gap of 1 mm on the upper side of an aperture electrode body 1 serving as a toner flow control means. The rear electrode roller 22 is a body (not shown)
It is rotatably disposed in the space and is configured to be able to convey the support body 20 inserted into the gap.

Below the aperture electrode body 1, along the longitudinal direction of the aperture electrode body 1, the toner supply device 1 is provided.
0 is disposed, and a transport roller 29 for transporting the support 20 between the aperture electrode body 1 and the back electrode roller 22 is rotatably arranged on the carry-in side of the aperture electrode body 1. Further, the fixing device 26 is installed at the destination of the support 20 conveyed by the back electrode roller 22.
Is provided.

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. And a toner carrying roller 14 as a toner carrying member, and a toner layer regulating blade 27. Here, the toner carrying roller 14 carries the toner 16 in layers.
The feeding roller 12 feeds the toner 16 to the toner carrying roller 14.

The supply roller 12 and the toner carrying roller 14 are rotatably supported in the toner case 11 in the direction of the arrow shown in FIG. Further, the toner layer regulating blade 27
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. 3, the toner carrying roller 14 is composed of a metal roller on which a resin toner carrying spacer 17 having a height of 15 μm is formed in a strip shape. The four toner carrying spacers 17 are arranged at equal intervals along the lengthwise direction of the roller. Therefore, the toner carrying portion 18 is formed by the metal roller surface between the toner carrying spacers 17.
Is configured.

As shown in FIG. 2, the aperture electrode body 1 includes a polyimide insulating sheet 2 having a thickness of 25 μm, and a plurality of apertures 6 having a diameter of 100 μm penetrating the insulating sheet 2 in a row at equal intervals. A control electrode 4 as a toner flow control unit is formed with a thickness of 1 μm at the periphery of the opening of each aperture 6 on the upper surface side of the insulating sheet 2 while being arranged.

The aperture electrode body 1 is at a position where the control electrode 4 faces the support body 20 as shown in FIG. 1 and at the position of the aperture 6 of the insulating sheet 2 as shown in FIG. It is slidably contacted with the toner carrying spacer 17 so as to be closest to the toner 16 on the toner carrying portion 18, and therefore, the insulating sheet 2 of the aperture electrode body 1 and the toner carrying portion of the toner carrying roller 14 are arranged. A gap through which the toner 16 can pass is formed between the toner 18 and the toner. At this time, needless to say, the toner carrying spacer 17 is in contact with the insulating sheet 2 at a position other than the aperture 6.

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

Further, a DC power source 24 is connected between the back electrode roller 22 and the toner carrying roller 14, and this DC power source 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. Then, the toner is carried on the toner carrying portion 17 of the toner carrying roller 14. The carried toner 16 is thinned by the layer regulation blade 27 to a thickness equal to the thickness of the toner carrying spacer 17, and then is carried toward the aperture electrode body 1 by the rotation of the toner carrying roller 14.

At this time, since the toner carrying spacer 17 of the toner carrying roller 14 is in sliding contact with the insulating sheet 2 of the aperture electrode body 1, the toner on the toner carrying portion 17 is compressed by the insulating sheet 2. It is supplied under the aperture 6 while contacting the insulating sheet 2. Therefore, on the toner carrier 17, uneven toner carrying does not occur, and the toner is uniformly supplied under the aperture 6.

On the other hand, the supporting body 20 is conveyed by the conveying roller 29 between the aperture electrode body 1 and the back electrode roller 22.

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, an electric force line from the control electrode 4 toward 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 is subjected to an electrostatic force in the direction of higher potential, and the toner from the toner carrying roller 14 is moved to the aperture 6 side.
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.

At this time, in the present embodiment, the aperture 6
The toner carrying spacer 1 on the toner carrying roller 14.
Since the aperture electrode body 1 is supported by 7, the toner 16 on the toner carrying portion 18 does not disturb the layer thickness and the like by sliding with the aperture electrode body 1, and thus a predetermined toner amount can be stably maintained. The image can be supplied, and an image having no density unevenness can be formed.

A voltage of 0V is applied from the control voltage application circuit 8 to the control electrode 4 corresponding to the non-image portion.
As a result, between the toner carrying roller 14 and the control electrode 4,
Since the electric field is not formed, the toner carrying roller 14
The upper toner 16 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.

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, in the above embodiment, the control voltage of the aperture corresponding to the non-image portion is set to 0V, but this may be a negative voltage. In this case, an image with less fogging can be obtained.

Further, in the above embodiment, the toner carrying spacer 17 is formed in a belt shape, but it may be a plurality of linear arrangements in the roller longitudinal direction as shown in FIG. Further, it may be spirally provided on the roller. In this case, since the toner layer and the toner-carrying spacer slide alternately on the back surface of the aperture electrode body, the toner-carrying spacer has a great effect of scraping the toner adhering to the back surface of the aperture and preventing the toner from clogging the aperture.

In the above-described embodiment, the toner carrying spacer 16 is made of resin, but it may be made of the same metal as the toner carrying portion.

Even when a large number of dimples are formed on the metal roller and the dimples of each dimple are used as the toner carrying portion and the other roller surface is used as the toner carrying spacer portion, the same effect as that of the above-described embodiment is expected. it can.

Further, the toner carrying spacer may be formed on the side of the toner carrying roller of the aperture electrode body.

[0035]

As is apparent from the above description, according to the image forming apparatus of the present invention, the unevenness of the toner supply amount on the toner carrier due to the sliding is eliminated, and as a result, the unevenness of the density of the recorded image is eliminated. Therefore, a high quality image can be formed.

[Brief description of drawings]

FIG. 1 is a sectional view 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 of a toner carrying roller and an aperture electrode body used in the image forming apparatus of the present invention.

FIG. 4 is a diagram showing another embodiment.

[Explanation of symbols]

 1 Aperture Electrode Body 2 Insulating Sheet 4 Control Electrode 6 Aperture 14 Toner Carrier Roller 16 Toner Carrier Spacer 17 Toner Carrier Part 22 Rear Electrode Roller

Claims (2)

[Claims] 1. A toner flow control means having a toner flow control section, a toner carrier for supplying the toner charged to the toner flow control means, and the toner carrier on the opposite side of the toner flow control means. It consists of a back electrode provided in
An image forming apparatus for controlling the passage of toner supplied from a toner carrier through a toner flow controller to form an image on a support supported on a back electrode, wherein the toner carrier and the toner flow control means are provided. An image forming apparatus characterized in that a spacer portion for forming a gap is disposed between the toner carrying portion and the toner flow control means. 2. The image forming apparatus according to claim 1, wherein the toner carrying member is composed of a toner carrying section for carrying toner in a layered manner and the spacer section.