JPH0347503B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording device, and particularly to an image recording device in which a voltage is applied imagewise to a group of electrodes and a developer is moved to a recording member placed on the group of electrodes. .

Conventionally, developer powder (hereinafter referred to as toner) is layered (hereinafter referred to as toner), and a voltage is applied to a pin electrode or the like to partially transfer the toner onto a recording member placed on this electrode. The method of directly obtaining an image on plain paper, which is a recording material, is
Several proposals have been made in Publication No. 34004 and Japanese Patent Application Laid-Open No. 49-87333.

This type of conventional recording method has the advantage that an image can be directly obtained on plain paper through a simple process. However, the toner adheres to the toner transport medium, and the adhesion strength varies depending on the individual toner particles. For this reason, a large voltage, such as a voltage applied to the electrodes, is required for recording, and there are also disadvantages in that the density is low and the microscopic image is likely to be fogged.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional example, and to reduce the adhesion force of toner to the toner transport medium at the recording position, reduce the applied voltage required for recording, and furthermore provide clear and fog-free images. It makes it possible to obtain images.

The image recording apparatus of the present invention, which achieves the above object, has at least one pair of electrodes disposed at a minute interval on a toner conveying member, and while applying electric fields periodically in different directions between the electrodes, the toner is One-component toner is conveyed by passing it over the electrodes of the conveying member, a recording member is disposed close to the gap between the electrodes, and this recording member is placed on the side opposite to the side where the recording member faces the toner conveying member. The third one is close to or in contact with the recording member.
A signal voltage is applied to this third electrode.

In the above configuration, when the toner conveying member has a fixed cylindrical shape, a magnetized rotating magnet is disposed inside to convey the toner, and when the toner conveying member has a rotating cylindrical shape, the above-mentioned minute A large number of spaced electrodes are provided along the cylindrical surface, and magnet means fixed inside the conveying member is provided to convey the toner.

With the above configuration, the toner that has reached the recording position on the toner transport member is subjected to the action of an electric field that periodically differs in direction between the plurality of electrodes provided on the transport member, and reciprocates between these electrodes. As a result, the toner separates from the conveying member, so the adhesion between the conveying member and the toner is weakened, and even if the voltage applied to the recording electrode on the recording medium side is low, the toner can be successfully transferred to the recording medium side. Further, when the toner is reciprocated at the development position of the conveyance member, any agglomeration of the toner is dispersed, so it is possible to form stable images over a long period of time using the same toner.

FIG. 1 shows an embodiment of the present invention, in which numeral 1 denotes a web-shaped recording medium, 2 an electrode member for applying an image-shaped signal voltage, and 3 a means for conveying toner to a recording position. The toner 5 in the toner container 4 is a one-component magnetic toner, and this toner is transported by the action of a magnet 7 in which magnetic poles of different polarity are alternately magnetized, which rotates inside a toner transport member 6 made of a non-magnetic cylinder. The member 6 is conveyed in a direction opposite to the rotation of the magnet 7.
When the toner on the toner conveying member 6 passes through the doctor blade 8, it is formed into a uniform thin layer by the action of this blade and reaches the recording position. Recording position 10
The toner that has reached the recording medium 1 adheres to the recording medium 1 in correspondence with the electrode to which a voltage is applied among the many electrodes 9 arranged in the width direction of the recording medium, thereby forming an image. The toner image on the recording medium 1 is then fixed by means such as heating and pressure.

An enlarged sectional view of the vicinity of the recording position 10 is shown in FIG.

As shown in the figure, the recording position 10 of the toner conveying member 6
A pair of electrodes 11 and 12 are placed near the
is arranged, and an alternating voltage, for example, whose direction changes periodically is applied to this electrode. When the toner transport member 6 is made of a conductive material, the electrodes 11 and 12 are provided with an insulating layer interposed therebetween. Here, the electrodes 11 and 1 are
The toner that has moved onto the electrode 2 is subjected to a force that causes it to reciprocate between the electrodes 11 and 12 due to the effect of this alternating current electric field. When the toner is insulating, it is effective to use a toner mixed with or mixed with a charge control agent because it can be stably charged to a specific polarity.

When the toner is subjected to the force of reciprocating movement between the electrodes in this manner and is not attached to the toner conveying member 6 or the adhesion force is weakened due to the reciprocating movement, a voltage is applied to the electrode 9. The toner easily moves and adheres to the recording medium 1. Therefore, a high voltage is not required to be applied to the electrodes, and stable recording is possible with a low applied voltage. For high-speed recording, the electrodes 9 are preferably arranged in a state in which a large number of electrodes are arranged, for example, at a ratio of 4 to 20 electrodes per 1 mm, and each electrode is individually connected to a signal source. connected to. Further, in order to further increase the recording density, the positions of the electrodes may be shifted to form two rows in a staggered manner. On the other hand, in this embodiment, it is preferable that the distance between the toner conveying member 6 and the recording medium 1 is approximately 50 to 300 microns. For example, if it is 200 microns, the bias effect on the electrodes
Image formation is possible with an applied voltage of about 200V.
The distance between the electrodes 11 and 12 is determined by the toner transport member 6.
Good results have been obtained when the spacing is about the same as or smaller than the spacing between the recording medium 1 and the recording medium 1, and a spacing of 50 to 300 microns is particularly desirable. Among them, when the spacing is 100 microns, even an AC voltage of about 100V produces toner agitation and movement effects at low voltage.

As for the method of applying the AC voltage, a constant DC voltage may be applied to one of the electrodes and an AC voltage applied only to the other electrode, or as in the case of the power supply 13 shown in FIG.
Voltages of opposite polarity may be applied to both electrodes. The frequency of the alternating current voltage is selected from several hundred hertz to several tens of kilohertz depending on the recording speed. In order to prevent the influence of frequency from appearing as "unevenness" in the image, it is desirable to apply an alternating current voltage of one cycle or more within the recording time of one example of the recording electrode.

As explained above, according to the present invention, toner is attached to the toner conveying member by applying voltages of different polarities to the plurality of electrodes of the present invention provided on the toner conveying member in the vicinity of the recording electrode at the recording position. The attachment force is weakened and recording is possible with a lower applied voltage.
Furthermore, since the toner is sufficiently agitated at the recording position,
Variations in toner adhesion due to environmental changes have less influence on recording characteristics. Therefore, stable recording is always possible. In addition, when the magnet in the toner is fixed and the conveying member is rotating, the electrodes of the present invention are arranged on the entire circumferential surface of the toner conveying member, and a plurality of these electrodes are brought to a predetermined position for recording. The voltage may be applied only when the voltage is applied.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a recording apparatus according to the present invention, and FIG. 2 is a partially enlarged sectional view of a recording position. In the figure, 1 is a recording medium, 2 is a recording electrode group,
Reference numeral 6 indicates a toner conveying member, and reference numerals 11 and 12 indicate AC voltage application electrodes.

Claims (1)

[Claims] 1. Arranging at least one pair of electrodes with a small interval on the toner conveying member, and applying an electric field in periodically different directions to the electrodes, the toner of the toner conveying member is transferred to the one-component toner on the electrode. A recording member is disposed close to the space between the electrodes, and a signal is generated by approaching or contacting this recording member on the side opposite to the side facing the toner conveying member. An image recording device that is provided with a recording electrode and applies a signal voltage to the recording electrode.