JPS58145468A - Image recorder - Google Patents

Abstract

PURPOSE:To obtain clear-cut pictures with lesser fogging by making separation of toner from a toner carrier better by a method in which the toner carrier is closely set on the surface of a recording paper, recording electrode group is provided on the back, the other electrode is provided on the upstream side, and AC voltage is applied between the toner carrier and the other electrode. CONSTITUTION:A toner carrier 6 to feed toners in a laminar state is closely set on the surface of a recording paper 1, a recording electrode group 2 is provided on the back of the paper, the other electrode 11 is provided on the upstream side (of flowing direction of the paper), and AC voltage is applied between the other electrode 11 and the toner carrier 6. The preferred frequency of the AC voltage to be applied is between hundreds kH2 and tens kH2 according to the recording speeds, and its amplitude value is preferably 200-800V. By this, when the distance between the toner carrier 6 and a paper 1 is set to 200mum, signal voltage to be applied between the recording electrode group 2 and the toner carrier 6 is only about 100-300V and therefore, fogging is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus, and particularly to an apparatus for recording an image by transferring a developer to a recording medium by applying a voltage to an electrode group in an imagewise manner.

Conventionally, developer powder (toner) is layered on a toner-carrying member (called a donor), and by applying a voltage to a pin electrode, the toner is partially deposited onto plain paper, which is a recording member, in the form of an image. Several methods have been proposed to directly obtain images on plain paper by transferring the
4004. JP-A-49-87333, etc.). These methods have the advantage of being able to directly obtain images on plain paper in a simple process, but the layered toner adheres to the toner carrying member, and the adhesion force is dependent on the individual toner particles. Because of the unevenness, a large voltage is required for recording, and the resulting image has the disadvantage of being prone to fogging in which the degree of a is light.

The present invention eliminates the drawbacks of the conventional example described above, reduces the adhesion force of toner to the toner carrying member at the recording position, makes it possible to reduce the applied signal voltage required for recording, and produces clear images without fog. The present invention provides an image recording device that makes it possible to obtain images.

The image recording apparatus of the present invention includes a toner carrying member that conveys toner in a layered manner to a position close to a recording medium, and a side opposite to the side of the recording medium facing the toner carrying member at the next position. An electrode group is arranged on the side so as to be close to or in contact with the recording medium, and a signal voltage corresponding to the image to be recorded is applied to the electrode group to transfer the toner from the toner carrying member to the recording medium in the form of an image. In the image recording device, the toner is transferred to the toner carrying member, and means for applying an alternating current voltage between another electrode disposed close to and upstream of the electrode group, another electrode, and the toner carrying member; It is characterized by having the following.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of an image recording device based on the aAK of the present invention as a cross-sectional view. In this figure, 1 is a recording medium such as plain paper, which moves in the direction of the arrow. 1
is a general representation of the electrode assembly to which a voltage is applied for image recording.

3 is an overall representation of a means for supplying and conveying toner to the recording position 10, in which a toner container 4 stores l-component magnetic toner 5, and a toner carrying member made of a non-magnetic cylinder comes into contact with the toner container 4. A magnet 7 is provided inside the toner carrying member 6, and the toner 5 adheres to the surface of the toner carrying member 6 and is conveyed to the recording position 1.0 by rotation in the direction of the arrow. The action of the doctor blade 80 forms the toner on the surface of the carrier member 6 into a thin layer of uniform thickness. At the recording position 10, the image forming electrode group 9 of the electrode assembly 2 is placed close to or in contact with the recording medium 1 on the side opposite to the toner bearing member 6 of the recording medium 1 facing the toner bearing member 6. It is placed. The toner that has reached the recording position 10 is transferred from the toner carrying member 6 to the recording medium 1 in an image-like manner when a signal voltage corresponding to the self-image is applied to the electrode group 9 and adheres thereto, forming an image. Ru. The toner image on the recording medium 1 is fixed by means such as heating and pressure.

FIG. 2 shows an enlarged view of the vicinity of the recording position 10 in FIG. In the electrode group 9 for applying a signal voltage, there is a separate electrode 11 on the upstream side in the toner transport direction, and an insulator 12.
This electrode and the toner supporting member 6
An alternating current voltage is applied between them. The toner that has been conveyed near the recording position 10 is subjected to a force of reciprocating movement between the toner carrying member 6 and the recording medium 10 due to the action of this alternating current electric field. If the toner is insulative, a charge control agent is mixed or mixed to make it easier to charge to a specific polarity1.
When a signal voltage is applied to the electrode group 9 while the toner is not attached to the toner carrying member 6 due to the force of reciprocating motion or the adhesion force is weakened, the toner easily moves. moves from the carrier member 6 to the recording medium 1 and adheres thereto;
Stable recording is possible with low signal voltage. As is well known, it is preferable for the electrode group 9 to consist of a large number of electrodes lined up in order to record high-performance equipment, and each
They are arranged at a ratio of ~20 and individually connected to the signal source.

Further, in order to make the recorded image even more detailed, the positions thereof may be shifted and arranged in two rows. Toner carrying member 6 and recording medium 1 (It is preferable that the distance between D is 50 to 300 microns, and when it is 200 microns, the AC voltage applied to the coil is about 200 to 800 V in amplitude value, and the signal voltage is about 100 to 300 V. In order to apply an AC voltage, a constant DC voltage is applied to one of the electrode 11 and the toner carrying member 6 to prevent toner from adhering to the background portion of the recording medium, and the other is applied with a constant DC voltage. Alternatively, as shown at 13 in FIG. 2, the AC voltage may be applied only to the electrode 11.The frequency of the AC voltage varies from several hundred cycles to several hundred cycles depending on the recording speed. A value of several tens of kilocycles is chosen.

As explained above, in the image recording apparatus of the present invention, an AC voltage is applied to separate electrodes provided near the upstream side of a group of electrodes to which a signal voltage corresponding to an image to be recorded is applied. Since the adhesion force of the toner to the toner carrying member at the recording position is reduced, the signal voltage lost to recording can be reduced, and the above-mentioned adhesion force variation due to product term variation, toner variation, etc. can be reduced. Since the influence on the recording characteristics is reduced, stable image recording with good image quality can be performed at all times.

[Brief explanation of drawings]

1 is a schematic sectional view of one embodiment of the image recording apparatus according to the present invention, and FIG. 2 is an enlarged view of the vicinity of the recording position in FIG. 1. 1... Recording medium 4... Toner container 6...
- Toner carrying member 7...Magnet 8...Doctor blade 9...Signal voltage is applied to pole group 11...AC voltage application electrode Fig. 1

Claims (1)

[Claims] a toner carrying member that conveys toner in a layered manner to a position close to the recording medium; and a toner carrying member that is close to the scissors and on the side opposite to the side facing the toner carrying member of the cough recording medium so as to be close to or in contact with the corpse recording medium. an image recording apparatus comprising a group of arranged electrodes, and applying a signal voltage corresponding to an image to be recorded to the electrode group to transfer toner from the toner carrying member to a recording medium in the form of an image; The image is characterized by further comprising: another electrode disposed close to and upstream of the electrode group; and means for applying an alternating current voltage between the other electrode and the toner carrying member. Recording device.