JPH05138921A - Image forming device - Google Patents

Abstract

PURPOSE:To manufacture an image forming device in which toner is fed into a toner passing opening formed on a base and the fear of clogging the toner passing opening is eliminated. CONSTITUTION:A signal electrode 35 and a common electrode 33 are installed across a toner passing opening 31a on an insulated base 31, and an electric field is formed between both electrodes 35 and 33 to allow the toner to pass through the toner passing opening 31a. A conductive mesh component 80 is installed on the toner feeding side of the insulated base 31, and an electric field of same direction as that of the electric field formed between both electrodes 35 and 33 is formed between the mesh component 80 and the signal electrode 35.

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 using powder toner.

[0002]

2. Description of the Related Art An image forming apparatus using a powder toner as an image recording medium is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-57658. Such an image forming apparatus is usually provided with a toner control mechanism for controlling charged toner particles to pass through a pinhole-shaped toner passage hole by an electrostatic attraction force generated according to an image output signal. Has been
The toner control mechanism selectively feeds toner particles onto the recording paper to form a predetermined recorded image on the recording paper.

An example of such an image forming apparatus is shown in FIG. This image forming apparatus uses a two-component developer that carries toner by a carrier, and has a developer container 100 that contains the two-component developer. The developer container 100 is provided with a supply roller 120 that rotates in the direction of arrow B and supplies the toner in the developer downward. A bias voltage is applied to the toner supply roller 120 by a bias electrode 121. Below the toner supply roller 120, a metal mesh 110 is horizontally arranged in order to separate only the toner from the magnetic brush of the two-component developer adhered to the supply roller 120 and drop the toner downward. ..

Below the mesh electrode 110, a toner control mechanism 130 for controlling the powder toner is provided. The toner control mechanism 130 includes an insulating substrate 131 provided with a large number of pinhole-shaped toner passage holes 132, and each toner passage hole 13.
It has a pair of electrodes 135 and 133 provided so as to sandwich the insulating substrate 131 so as to form an electric field in the electrode 2. Each of the paired electrodes 135 and 133 has a corresponding toner passage hole.
Pinhole-shaped through holes having the same size as 131 are provided, and the through holes are attached to one surface of the insulating substrate in a state of being aligned with the toner passage holes 131. Then, a predetermined voltage applied from the image information generating mechanism 150 is applied between the electrodes 135 and 133 to form an electric field in the toner passage hole 131 in the direction in which the toner passes, so that the toner particles become toner particles. It passes through the passage hole 131. To prevent toner particles from passing through the toner passage hole 131, the toner passage hole 13
The image information generating mechanism 150 includes the electrodes 135 so that an electric field in the direction opposite to that in the case of passing the toner is formed in the electrode 1.
And 133 is applied with a predetermined voltage. An ultrasonic vibration generator 136 is provided on the insulating substrate 131, and the ultrasonic vibration generator 136 ensures that the toner flows into the toner passage hole 131.

A base electrode 160 is provided on the recording paper arrangement side, which is the toner passage direction side in the toner control mechanism 130, and the recording paper is arranged on the base electrode 160. Then, an electric field is formed between the base electrode 160 and the electrode 135 on the toner supply side of the toner control mechanism so that the toner can surely move in the recording paper direction.

Toner control mechanism 130 and toner supply roller 1
Bias voltage applying means 140 for applying a DC bias voltage or an AC bias voltage is connected to the mesh 110 provided between the mesh 110 and the mesh 110. When a DC bias is applied, the toner supply from the mesh electrode 110 is promoted, and when an AC bias is applied,
Since the toner vibrates vertically according to the frequency of the AC bias, the mesh electrode 110 is prevented from being clogged with the toner.

In such an image forming apparatus, a dot (dot) is formed on the recording paper 70 by the toner passing through each toner passage hole 132, and an image such as a character is formed by the aggregate of the dots. Since the toner image formed on the recording paper is unfixed, the recording paper is conveyed to the fixing device, and the toner is heated and melted by the fixing device, so that the toner is fixed on the recording paper. To be done.

[0008]

In such an image forming apparatus, a DC bias or an AC bias is applied to the mesh 110 from the bias voltage applying means 140 regardless of the image signal from the image information generating mechanism 150. for,
There are the following problems. When a DC bias is applied to the mesh 110, toner is supplied from the mesh 110 to the toner passage holes 132 even when an image is not formed on the recording paper. For this reason, the toner that has entered the toner passage hole 132 may adhere to the toner passage hole 132 and clog the toner passage hole 132. When the AC bias is applied to the mesh 110, the toner supplied from the mesh 110 reciprocates due to the alternating electric field whose polarity is reversed. Therefore, the amount of toner supplied from the mesh 110 to the toner passage hole 132 varies,
The density of the image formed on the recording paper 70 may vary.

The present invention solves such a problem, and an object thereof is to prevent clogging of the inside of the toner passage hole with the toner and to always keep a predetermined amount of toner in the toner passage hole. An object of the present invention is to provide an image forming apparatus capable of passing light.

[0010]

An image forming apparatus of the present invention is provided with a toner passage hole through which toner passes, a substrate to which the toner is supplied, and a substrate to which the toner is supplied. A conductive mesh member arranged so that the toner passing therethrough, a pair of electrodes arranged so as to sandwich the substrate so as to form an electric field in the toner passing hole, and each toner passing according to the image information. Image information generating means for applying a potential between the two electrodes so as to form electric fields in the holes in the toner passing direction and the electric field in the opposite direction, respectively, and recording paper arranged on the toner passing direction side of the substrate. And a base electrode to which a bias voltage is applied so that the toner having passed through the toner passage hole is attached, and an electric field formed in the toner passage hole by the image information generating means. It was and means for forming between one of the electric field in the same direction of the mesh member and the electrode, the objects can be achieved.

[0011]

In the image forming apparatus of the present invention, an electric field is formed in the toner passage hole provided on the substrate by the pair of electrodes,
The toner supplied to the substrate passes through the toner passage hole due to the electric field. A base electrode is provided on the side of the substrate in the toner passage direction so that the recording paper is positioned so that the toner that has passed through the toner passage hole is attached to the base electrode so as to suck the toner that has passed through the toner passage hole. Bias voltage is applied. Then, the toner having passed through the toner passage hole adheres to the recording paper to form a predetermined toner image. The toner supplied to the substrate passes through a conductive mesh member, and an electric field in the same direction as the electric field formed in the toner passage hole by the image information generating means is formed on the mesh member. It is supposed to be done.
Therefore, when the toner is passed through the toner passage hole, the toner supply from the mesh member to the substrate is promoted,
When the toner does not pass through the toner passage hole, the toner is sucked from the substrate to the mesh member.

[0012]

EXAMPLES Examples of the present invention will be described below. As shown in FIG. 1, the image forming apparatus of the present invention has a developer container 10 in which a two-component developer in which powder toner and carrier are mixed is contained. An opening 11 that opens downward is formed in the lower part of the developer container 10, and a toner supply roller 20 that supplies toner downward is rotatably arranged in the opening 11. Has been done. The toner supply roller 20 has a built-in magnet for forming a magnetic brush, and the powder toner stored in the developer storage container 10 moves in the direction indicated by the arrow B in FIG. By being rotated, it is sequentially supplied downward. A negative bias voltage is applied to the toner supply roller 20 from the DC power supply 21.

Below the toner supply roller 20, a conductive mesh member 80 is placed horizontally in order to separate only the toner from the magnetic brush of the two-component developer adhering to the supply roller 20 and drop it downward. It is located in. This mesh member 80 is connected to the negative DC power source via the changeover switch 81.
82 and the positive DC power source 83 are selectively connected. The changeover switch 81 can be changed over in conjunction with the output of the image information generating mechanism 50 described later.

Below the mesh member 80, the toner control means 30 is provided in the vicinity of the mesh member 80. The toner control mechanism 30 has an insulating substrate 31 arranged horizontally. On the insulating substrate 31, a large number of toner passage holes 31a penetrating in the vertical direction are arranged in parallel along the axial direction of the toner supply roller 20. Each toner passage hole 31a has a constant inner diameter. Further, an ultrasonic vibration generator 40 is arranged on the insulating substrate 31, and ultrasonic vibration is applied to the insulating substrate 31 by the ultrasonic vibration generator 40.

Signal electrodes 35 are provided on the surface of the insulating substrate 31 on the supply roller 20 side so as to correspond to the toner passage holes 31a. Each signal electrode 35 has a toner passage hole 31a. A through hole 35a having a similar diameter is formed. Each signal electrode 35 is fixed to the insulating substrate 31 so that each through hole 35a is in communication with each toner passage hole 31a. A common electrode 33 is provided on the surface of the insulating substrate 31 on the base electrode 60 side so as to correspond to each toner passage hole 31a. Each common electrode 33 is provided with a through hole 33a having the same inner diameter as each toner passage hole 31a of the insulating substrate 31,
The respective common electrodes 33 are attached to the insulating substrate 31 such that the respective through holes 33a are aligned with the respective toner passage holes 31a of the insulating substrate 31.

An image information generating mechanism 50 is provided between the signal electrode 35 of the insulating substrate 31 and the common electrode 33. The image information generating mechanism 50 includes a word processor, a facsimile,
It operates in response to signals from the main body of the device such as a computer, and gives an electric signal corresponding to image information to each signal electrode 35. For example, +100 for information that should form an image
The voltage of V is applied, and in the case of non-image information that does not need to form an image, the voltage of -100V is controlled to be applied.

The output of the image information generating mechanism 50 is a changeover switch.
It is also given to 81, and as shown in FIG. 2, +100 V as image information for forming an image from the image information generating mechanism 50.
When the voltage is output, the changeover switch 81 is switched to the negative power source 82 side to apply a negative bias voltage to the mesh member 80. On the contrary, when a voltage of -100V is output from the image information generating mechanism 50 as non-image information that does not form an image, the changeover switch 81 is switched to the sex power source 83 side,
A positive bias voltage is applied to the mesh member 80. Figure 2
Shows the potential of the signal electrode 35 to which the signal from the image information generating mechanism 50 is applied and the potential of the mesh member 80. When the image information signal is applied to the signal electrode 35 and becomes a positive potential, the mesh member 80 is applied with a negative potential. Therefore,
The negatively charged toner supplied on the mesh member 80 is
The signal is supplied from the mesh member 80 to the signal electrode 35. On the other hand, when a negative potential is applied as the non-image information from the image information generating mechanism 50 to the signal electrode 35, a positive potential is applied to the mesh member 80 and the negatively charged toner on the signal electrode 35 is transferred to the mesh member. Inhaled to 80.

A metal base electrode 60 is provided below the toner control mechanism 30 so as to face the toner control mechanism 30. A recording paper 70 on which a toner image is formed is arranged on the upper surface of the base electrode 60, and the recording paper 70 is conveyed on the base electrode 60 in the direction indicated by arrow A in FIG. A predetermined positive bias voltage is applied to the base electrode 60.

When a predetermined toner image is formed on the recording paper 70 by the toner control mechanism 30, the recording paper 70 is conveyed to a fixing device (not shown) and the toner image is fixed.

An image forming process by the image forming apparatus having such a configuration will be described. Toner supply roller 20
When is rotated, the toner contained in the developer in the developer container 10 is supplied to the mesh electrode 80. Then, from the image information generating mechanism 50 to the signal electrode 35 of the toner control mechanism 30,
When a positive potential is applied as image information for forming an image, the changeover switch 81 is changed over and the mesh member 80
A negative potential is applied to. Thereby, the mesh member 80
The negatively charged toner supplied to the
It repels 80 and is attracted to the positively charged signal electrode 35 and supplied from the mesh member 80 to the signal electrode 35.
At this time, when a positive voltage is applied to the signal electrode 35 by the image signal generating mechanism 50, the signal electrode 3 is placed in the toner passage hole 31a.
Since an electric field from 5 toward the common electrode 33 is generated, the toner particles charged in the negative polarity are
To pass through the inside of the toner passage hole 31a, and further through the through hole 33a of the common electrode 33 to the base roller 60.
It is supplied on the upper recording paper 70. Since a sufficiently large positive bias voltage is applied to the base electrode 60 with respect to the signal electrode 35, an electric field formed by the base electrode 60 and the signal electrode 35 passes through the toner passage hole 31a. The toner is reliably supplied to the recording paper 70. The toner attracted by the base electrode 60 adheres to the surface of the recording paper 70, whereby a predetermined toner image is formed.

On the other hand, when a negative potential is applied to the signal electrode 35 as non-image information so that the image information mechanism 50 does not form an image, the changeover switch 81 is changed over and the mesh member 80 is supplied with the positive power source 83. A positive potential is applied. Therefore, the negatively charged toner remaining on the signal electrode 35 repels the negative potential signal electrode 35 and also has a positive potential mesh member.
Attracted to 80. Therefore, in this case, there is no possibility that the toner will pass through the toner passage hole 31a.

The present invention is not limited to the above embodiment, and a roller-shaped base electrode may be used instead of the flat-plate-shaped base electrode 60, for example.

[0023]

According to the image forming apparatus of the present invention,
According to the image signal from the image information generating means, the voltage applied from the DC power source to the mesh electrode is set to accelerate the toner supply when the image is formed and to prevent the toner supply when the image is stopped. The toner supply amount increases and the image density improves. On the other hand, when the image is not formed, unnecessary toner is not supplied, clogging of the toner passage hole is prevented, and a clear high-quality image is formed. be able to.

[Brief description of drawings]

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

FIG. 2 is a graph showing changes in potential of each electrode.

FIG. 3 is a longitudinal sectional view of a main part of a conventional image forming apparatus.

[Explanation of symbols]

 10 developer container 20 toner supply roller 30 toner control means 31 insulating substrate 31a toner passage hole 33 common electrode 35 signal electrode 50 image information generating mechanism 60 base electrode 80 mesh member 70 recording paper

Front page continuation (72) Inventor Masaaki Yukawa 1-22 Tamatsukuri Chuo-ku, Osaka Mita Engineering Co., Ltd.

Claims (1)

[Claims] 1. A substrate is provided with a toner passage hole through which the toner passes, and a substrate to which the toner is supplied, and a conductive material arranged to pass the toner supplied to the substrate. Mesh member, a pair of electrodes arranged so as to sandwich the substrate so as to form an electric field in the toner passage hole, and a direction in which the toner passes in each toner passage hole and an opposite direction depending on the image information. Image information generating means for applying a potential between the electrodes so as to form an electric field to each of the electrodes, and a recording paper disposed on the toner passage direction side of the substrate. A base electrode to which a bias voltage is applied so that the toner that has passed through the passage hole is attached, and an electric field in the same direction as the electric field formed in the toner passage hole by the image information generating unit are in front of the mesh member. Image forming apparatus comprising means for forming between one electrode.