JPH07242014A - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] To provide an image forming apparatus in which the density of an image to be formed does not fluctuate and the print quality does not deteriorate. [Structure] In the image forming apparatus, the control unit controls
In the above, the light emitting element is caused to emit light, and the light transmitted through the support body inserted from the insertion opening is received by the light receiving element,
The light transmittance of the support is measured. Next, in S3, based on the light transmittance of the support, it is determined whether the support is a normal paper or an OHP film, and if the support is an OHP film, the DC power source is controlled. Then, a voltage of + 330V is applied to the back electrode roller (S4), and if the support is a normal paper, a voltage of + 300V is applied (S5). As a result, the surface potential of the support on the side of the aperture electrode is always constant even if the type of support is changed, and therefore it is possible to record an image of a constant density without being affected by the type of support. You can

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 having a recording section for recording by controlling the flow of charged toner by means of toner flow control means.

[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 charged toner particles so that the flow of toner particles passing through the aperture is modulated by an electric potential, and a means for positioning the support in the particle flow path so that the support and the aperture electrode body can move relative to each other. And a back electrode arranged on the opposite side of the aperture electrode body with the support interposed therebetween.

Further, as a further improvement of this image forming apparatus, in the application of Japanese Patent Application No. 4-254494, an aperture electrode having an opening is arranged in contact with a toner carrier and the toner of the aperture electrode An image forming apparatus has been proposed in which a control electrode is formed on the periphery of the opening on the surface opposite to the carrier.

[0005]

However, in such a conventional image forming apparatus, when the type of the support supplied to the apparatus is different, the density of the formed image is changed and the print quality is deteriorated. I was afraid. In particular, the density of the formed image was greatly different between the case where the support was a plain paper and the case where the support was a film for an overhead projector (OHP). Upon investigating the cause, the dielectric constants of ordinary paper and OHP film are different, and therefore the potential on the surface of the aperture electrode body side generated by the voltage applied to the back electrode is for ordinary paper and OHP film. It turned out that it was different from the film.

The present invention has been made to solve the above-mentioned problems, and even if the type of the support supplied to the recording section is different, the density of the formed image does not change, An object of the present invention is to provide an image forming apparatus in which there is no fear that print quality will deteriorate.

[0007]

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. An image forming apparatus comprising a recording unit composed of a supply unit and a back electrode provided on the opposite side of the toner supply control unit with the toner flow control unit interposed therebetween, and a support supplied to the recording unit. Control means for changing the voltage applied to the back electrode based on the detection result of the detection means for detecting the type of the back electrode or the setting of the setting means for setting the type of the support supplied to the recording section. Is provided.

[0008]

According to the image forming apparatus of the present invention having the above structure, the control means changes the voltage applied to the back electrode based on the detection result of the detection means or the setting of the setting means. Thereby, even if the type of the support supplied to the recording unit is different, the density of the formed image does not change.

[0009]

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

That is, the structure of the recording unit of the image forming apparatus embodying the present invention will be described with reference to FIG. 1. The right side surface of the housing 30 of the image forming apparatus is an insertion for loading the support 20. The mouth 31 is formed and the housing 30
A cylindrical back electrode roller 22 as a back electrode is rotatably arranged on the housing with a gap of 1 mm above the aperture electrode body 1 as a toner flow control means arranged in the central portion of the. It is set up. Thereby, the insertion port 3
The support body 20 inserted from 1 and transported by the transport roller 32 is further transported to the left side while being in contact with the back electrode roller 22.

In the vicinity of the insertion opening 31 of the housing 30,
For detecting the transmittance of the support 20 passing therethrough,
A light emitting element 33 and a light receiving element 34 as a detecting means are arranged.

Below the aperture electrode body 1, a toner supply device 10 as a toner supply means is arranged along the longitudinal direction of the aperture electrode body 1, and by the back electrode roller 22. A fixing device 26 is disposed at the destination of the conveyed support body 20, and the support body 20 conveyed from the fixing device 26 is ejected to the outside of the device on the left side surface of the casing 30. A discharge port 35 is formed.

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 stored 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 18. Here, the toner carrying roller 14 carries the toner 16 and conveys it toward the aperture electrode body 1, and the supply roller 12 has the toner 16 with respect to the toner carrying roller 14.
To supply.

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 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.

In the aperture electrode body 1, as shown in FIG. 2, a plurality of apertures 6 having a diameter of 100 μm are formed in a row on an insulating sheet 2 made of polyimide having a thickness of 25 μm, and on the upper surface side of the insulating sheet 2. The control electrode 4 is formed with a thickness of 1 μm on the periphery of the opening of each aperture 6,
The aperture 6 and the control electrode 4 constitute a toner flow controller. As shown in FIG. 1, the aperture electrode body 1 is arranged so that the control electrode 4 faces the support body 20 side, and the insulating sheet 2 contacts the toner 16 on the toner carrying roller 14 at the position of the aperture 6. It is set up.

A control voltage applying circuit 8 as a control voltage applying means is connected between the control electrode 4 and the toner carrying roller 14. This control voltage applying circuit 8
The control electrode 41 is controlled by the control unit 41 described later, and the control electrode 4 is set to 0 based on the reception data sent from the host side.
It is configured to apply a control voltage of V or + 50V.

Further, a DC power supply 24 is connected between the back electrode roller 22 and the toner carrying roller 14, and the output voltage of this DC power supply is controlled by a control unit 41 described later. , The back electrode roller 22
A voltage of +300 to +330 V can be applied to

FIG. 3 shows the electrical construction of the image forming apparatus of this embodiment. The control section 41 of the image forming apparatus is
It is composed of a well-known microprocessor (CPU). A ROM 42 storing a control program and a RAM 43 having a line memory are connected to the control unit 41.

Further, a light emitting element 33 and a light receiving element 34 as detecting means for detecting the light transmittance of the support 20 are connected to the control section 41, whereby the light emitting element 33 emits light. The control is performed by the control unit 41, and the output from the light receiving element 34 is input to the control unit 41 via the A / D converter 46, and the light transmittance of the support 20 is detected. Further, the interface circuit 44 connected to the host is connected, whereby the image data sent from the host at the time of image formation is transferred to the RAM 43.
Of the line memory. Further, the control voltage application circuit 8 and the DC power supply 24 are connected to the control unit 41.

Further, the controller 41 includes the supply roller 12, the toner carrying roller 14 and the back electrode roller 2.
A plurality of motors 45 for driving the second motor etc. are connected, and their stoppage can be controlled.

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

First, when the print command and the image data are received from the host side through the interface circuit 44 (S1: YES), the control section 41 causes the light emitting element 33 to emit light in S2, and also from the insertion opening 31. The light transmitted through the inserted support 20 is received by the light receiving element 34, and the light transmittance of the support 20 is measured.

Next, in S3, the insertion opening 3 is determined based on the output from the light receiving element 34, that is, the light transmittance of the support 20.
It was judged whether the support 20 inserted from No. 1 was a normal paper or an OHP film, and if the light transmittance was high, the support 20 inserted from the insertion port 31 was an OHP film. In this case, the DC power supply 24 is controlled to apply a voltage of +330 V to the back electrode roller 22 (S
4). Further, when the support 20 inserted from the insertion opening 31 is a normal paper because of low light transmittance, the DC power supply 24 is controlled to +300 relative to the back electrode roller 22.
A voltage of V is applied (S5).

Next, in S6, recording is performed based on the received image data.

That is, when the control unit 41 drives the motor 45, the toner carrying roller 14 rotates in the direction of the arrow shown in FIG. 1 and the supply roller 12 also rotates in the direction of the arrow shown in FIG. The toner 16 sent from 12 is rubbed against the toner carrying roller 14, is negatively charged, and is carried on the toner carrying roller 14. The carried toner 16 is a layer regulation blade 18
After being thinned and further charged by the toner carrying roller 14, the toner carrying roller 14 is rotated and conveyed toward the aperture electrode body 1. Then, the toner on the toner carrying roller 14 is supplied to the bottom of the aperture 6 while being rubbed by the insulating sheet 2 of the aperture electrode body 1.

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, the control section 41 controls the control voltage applying circuit 8 based on the received data, and the control electrode 4 corresponding to the pixel of the image is set to + 50V from the control voltage applying circuit 8. It is applied only during the application time. As a result, an electric force line from the control electrode 4 toward the toner carrying roller 14 is formed near the aperture 6 corresponding to the pixel due to the potential difference between the control electrode 4 and the toner carrying roller 14. As a result, the negatively charged toner is
The toner carrying roller 14 receives the electrostatic force in the direction of high potential.
It passes through the aperture 6 from above and is drawn out 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 of normal density.

At this time, in this embodiment, when the support 20 inserted through the insertion opening 31 is a film for OHP, a voltage of +330 V is applied to the back electrode roller 22, and the insertion is performed. When the support 20 inserted through the opening 31 is a normal paper, the back electrode roller 2
Since the voltage of +300 V is applied to the voltage of 2, the surface potential of the support body 20 on the side of the aperture electrode body 1 is always constant even if the type of the support body 20 is changed. An image having a constant density can be recorded without being affected by the type of the support 20.

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, 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.

Next, in S7, it is determined whether or not the recording is completed. If the recording is not completed, the recording is continuously executed, and the toner image is formed on the entire surface of the support 20 by repeating the above process. It After that, the formed toner image is transferred to the support 20 by the fixing device 26.
The toner is fixed on the top and discharged from the discharge port 35 to the outside of the apparatus. If it is determined in S7 that the recording has ended, the control ends.

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 light transmissivity of the supporting member 20 is detected by the light emitting element 33 and the light receiving element 34 as the detecting means, and the supporting member 20 inserted from the insertion port 31 is a normal one. Although it is configured to judge whether it is a sheet or a film for OHP, for example, as shown in FIG. 5, for setting whether the support 20 inserted from the insertion port 31 is a normal sheet or a film for OHP. An operation panel 47 including a setting switch 47a may be provided, and the control unit 41 may control the output voltage of the DC power supply 24 based on the setting state of the setting switch 47a on the operation panel 47. That is, when a film for OHP is set by the setting switch 47a, a voltage of + 330V is applied to the back electrode roller 22, and when a normal sheet is set, the back electrode roller 22 is set. To +3
The voltage of 00V may be applied. In addition to this, the support 20 may be set by the command from the host side via the interface circuit 44 to be a normal paper or a film for OHP, and the setting switch 47a on the operation panel 47 and the control. The unit 41 and the like constitute the setting means described in claim 3.

Further, 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.

In the above embodiment, the aperture electrode body was used as the toner flow control means, but it is also possible to use, for example, a knitted electrode body as described in JP-A-1-503221. .

[0036]

As is apparent from the above description, according to the present invention, even if the type of the support supplied to the recording section is different, the density of the formed image does not change, It is possible to provide an image forming apparatus in which the print quality is not likely to deteriorate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration of an aperture electrode body used in a recording section.

FIG. 3 is a block diagram showing an electrical configuration of the image forming apparatus.

FIG. 4 is a flowchart showing the operation of the image forming apparatus.

FIG. 5 is a block diagram showing an electrical configuration of another embodiment.

[Explanation of symbols]

 1 Aperture electrode body 2 Insulating sheet 4 Control electrode 6 Aperture 8 Control voltage application circuit 14 Toner carrier roller 22 Back electrode roller 24 DC power supply 31 Control section 33 Light emitting element 34 Light receiving element

Claims (3)

[Claims] 1. A toner flow control means having a toner flow control section, a toner supply means for supplying charged toner to the toner flow control means, and a toner flow control means on the opposite side of the toner flow control means. In an image forming apparatus including a recording unit composed of a back electrode provided in the recording unit, a detection unit for detecting the type of the support supplied to the recording unit is provided, and the detection result of the detection unit is provided. An image forming apparatus comprising: a control unit that changes a voltage applied to the back electrode based on the above. 2. The detecting means measures the transmittance of the support, and the control means applies the back electrode when the transmittance of the support is high as compared to when the transmittance is low. The image forming apparatus according to claim 1, wherein the voltage is set high. 3. A toner flow control means having a toner flow control section, a toner supply means for supplying charged toner to the toner flow control means, and an opposite side of the toner flow control means from the toner flow control means. In an image forming apparatus including a recording unit configured with a back electrode provided in the recording unit, a setting unit for setting the type of the support supplied to the recording unit is provided, and based on the setting of the setting unit. An image forming apparatus comprising a control means for changing a voltage applied to the back electrode.