JPS6124464A - Image recorder - Google Patents

Abstract

PURPOSE:To raise magnetic flux density in the tip of a recording cell by securing a space for a removing means of unnecessary toners between a recording medium and a recording magnet having a portion where there are greater magnetomotive forces on the opposite side of the recording medium. CONSTITUTION:Magnets 13a and 13b having greater magnetomotive forces are attached to the opposite side of recording medium 1 to the recording magnets 11a and 11b of the recording head having a recording cell group 8 and the magnets 11a and 11b. Magnetic flux density on the tip of the recording cell 8 can be raised, and since the magnets 11a and 11b are separated from the tip of the recording cell, the space for magnetic wires 14 and feeding screws 15 can be greatly increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image recording device, and particularly to an image recording device that directly attaches a component polar electromagnetic developer (hereinafter abbreviated as toner) to a recording medium in response to an image electric signal. The present invention relates to an image recording device that records images.

[Background of the invention]

A conventional image recording device of this type is U.S. Patent No. 3816.
Some of these are detailed in the specification of No. 840 and Japanese Patent Application Laid-Open No. 127578/1983. The outline of this conventional device is explained in Fig. 4. In Fig. 4, 1 is a recording medium, and in this example, it has a structure in which a dielectric layer 3 treated with alumite is provided on an aluminum cylinder 2. You may also use commercially available electrostatic recording paper. Aluminum cylinder 2 is grounded. 4 is a hollow/4'- containing conductive magnetic toner T;
Inside, a toner application roller 6 made of a hollow cylinder made of a non-magnetic conductive material is immersed in toner T, and a magnet 7 is fixed inside. This is a power source that applies a constant DC voltage to the 12 coating rollers 6. Magnetic recording electrodes 8 are arranged in the axial direction facing the recording medium 1, and are usually made by laminating a large number of thin wires of magnetic material, such as iron, copper alloy, nickel, etc., in parallel. , or by a technique such as magnetic sheet etching technique. This is electrically insulated and fixed to the body using an insulating adhesive (not shown), and is held between magnets 11a and 11b.

The recording electrodes 8 are each independently connected to a signal character generator 9.

The recording medium 1 rotates in the direction indicated by the arrow. On the other hand, the toner T in the hopper 4 is transferred to the toner application roller 6 by the action of the magnet 70.
9) The toner T is transported to the doctor blade 4' by the rotation of the toner application roller 6 in the direction of arrow B.
A uniform layer of toner is formed. When this toner T contacts the recording medium 1, a DC voltage is applied from the bias power supply 12, so that the toner T acquires a charge and adheres to the recording medium 1.

When the recording medium 1 further rotates in the direction of the arrow and the toner T on it reaches the recording position 10, the magnets 11a and llb
Ears of toner T are formed between the recording medium 1 and the recording electrode 8 under the influence of the magnetic field emitted from the recording medium 1 .

Furthermore, since the charge of the toner escapes through the dielectric layer 3 before reaching the recording section, the adhesion force of the toner to the recording medium 1 is mainly due to intermolecular force, and the recording electrode 8 It is weaker than the magnetic binding force caused by the ears of toner T formed at the tip. However, when a recording signal voltage selected according to the image pattern is applied from the character generator 9 to the recording electrode 8 at this time, a charge having a polarity opposite to that signal voltage is induced in the conductive layer 2.
Due to this induced charge, charge is injected into the toner T from the recording electrode 8. The charge injected into the toner T is transferred to the recording electrode 8.
It provides an electric force sufficient to overcome the magnetic binding force caused by the ears of toner T formed at the tip and sufficiently adhere the toner T to the recording medium 1. On the other hand, since there is no charge injection as described above in the area to which the recording signal voltage is not applied (non-image area), the adhesion force between the recording medium 1 and the toner 1 is mainly due to the intermolecular force, and the toner T The particles are removed from the recording medium by the magnetic binding force of the ears, and are further attracted by the magnetic field generated from the magnets 11a and 11b, and are deposited and accumulated near the magnets along the recording electrode 8. Although not shown, the toner image visualized on the recording medium 1 according to the above-mentioned image pattern is usually transferred to paper by corona discharge or pressure transfer and fixed by force 1.
, or if the recording medium 1 is electrostatic recording paper, it may be fixed as is. By the way, in the above-mentioned type of image recording apparatus, in order to obtain a clear image without fog, it is necessary to It is preferable that the magnetic flux density at the tip be as strong as possible without reducing the image recording density. However, in the past, in order to increase this magnetic flux density, the recording magnets 11a, 11b' were so large that there was not enough space to provide a means for removing unnecessary toner that adhered to and accumulated on the recording electrode group 8 and the recording magnets 11a, 11b'. The magnet must be placed close to the recording medium 1 or an expensive rare earth magnet must be used, both of which are impractical.

[Purpose of the invention]

An object of the present invention is to secure a space between the recording medium and the recording magnet for an unnecessary toner removing means and to increase the magnetic flux density at the tip of the recording electrode in this type of image recording apparatus.

[Summary of the invention]

A feature of the present invention is that in the above-mentioned type of image recording device,
The reason is that the recording magnet has a portion where the magnetomotive force is thicker on the side opposite to the recording medium.

In implementing the present invention, as shown in each embodiment described later, the magnets include a pair of magnets located on the recording medium side and a pair of magnets located on the opposite side from the recording medium and having a magnetomotive force larger than υ. or a pair of magnets whose thickness becomes thinner as they get closer to the recording medium, or a pair of magnets and a large magnet (such as a magnetomotive force) adjacent to each other with the same poles in between. It can consist of

[Embodiments of the invention]

Examples of the present invention will be described in detail below. Since the basic configuration is the same as that shown in FIG. 4, this will be explained with reference to FIG. The dielectric layer 3 was formed by alumite treatment with a thickness of 2 μm. Toner T contains 1o10 magnetic material.
Although a conductive toner having a conductivity of Ω-m or less can be used, in this example, carden was externally added to Imaging Powder 355) toner sold by A3M Company to adjust the conductivity to 105Ω. The recording electrode 8 is a pure iron wire f with a diameter of 20μ.
3,360 adhesives are lined up in parallel over a width of 210 tm and are sold by Cemedine Co., Ltd.
(product name) was used. The gap between the recording electrode 8 and the recording medium 1 was set to 75±25 μm in this example, although it depends on the recording linear density.

The recording medium 1 is rotated in the direction of the arrow at a circumferential speed of 180 cm/sec,
Similarly to the above explanation, after the toner T is applied with uniform pressure onto the recording medium 1 by the toner application roller 6, the recording electrode 8
When it reaches the position facing the character signal generator 9, 5so
By applying an image signal voltage of v, an image of toner T is recorded on the recording medium 1.

By the way, the recording magnet 11aellb shown in FIG.
In the case of a 0 Gauss magnet, the magnetic flux density at the tip of the recording electrode 8 is as low as 400 Gauss when the distance between the magnet and the tip of the recording electrode 8 is 5fi, and the unnecessary toner T on the recording medium 1 is
It cannot be removed sufficiently, and this appears as fog on the recorded image.

Therefore, in this embodiment, in order to prevent this, the recording head section (recording electrode group 8 and magnets 11m, 11b
Th). That is, as shown in the figure, a horizontal 12
m+, height 25m+, width 220m+, surface magnetic flux density 1350
Gauss magnet 13m.

13bt-install. Magnet 11a, Ilb and magnet 13a
, 13b have the same polarity. This allows the recording electrode 8
The magnetic flux density at the tip rose to 880 Gauss. This means that when obtaining a magnetic flux at the tip of the recording electrode of 400 Gauss, the magnet 1
1a, l1bt - 7-8 m+ to 1 from the recording electrode tip
This means that it may be separated by about 0 cm.

When recording was carried out in the same manner as shown in FIG. 4 using the recording head configured as described above, a clear toner image without fog could be obtained on the recording medium 1. And with this configuration,
The space for removing unnecessary toner accumulated near the recording magnets 11m and llb, for example, the magnetic wire 14 and the conveyance screw 15 that circulate in the direction toward the back and the front of the paper, can be greatly increased. .

FIG. 2 shows an embodiment of the present invention, in which the magnets 13a and 13b are replaced by a magnetic field having the same polarity as the magnetic pole facing the recording electrode 8 of the recording magnets 11a and llb. In this case, two magnets 16 are arranged.

FIG. 3 shows still another embodiment, in which the above-mentioned recording magnet 11
ae11b and magnets 12a, 12b'1i=integrated and obliquely shaped toward the recording medium;
In addition to producing the same effect as explained in the figure, if there is a large space between the recording medium 1 and the recording magnets 11a + 11b, there is a means for removing unnecessary toner that accumulates, such as a magnetic wire. 14 and a screw can be easily placed here.

〔Effect of the invention〕

According to the present invention, in this type of image recording device, the magnetic flux density at the tip of the recording electrode can be increased with a simple configuration, a clear image without fog can be obtained, and the space between the recording medium and the recording magnet can be enlarged. Since the width can be increased, it is possible to secure sufficient space there for a means for removing unnecessary toner accumulated on the recording electrode and recording magnet.
There is no need to use expensive rare earth magnets.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views of recording head sections according to different embodiments of the present invention, and FIG. 4 is a cross-sectional view showing a conventional example of an image recording apparatus to which the present invention relates.・Recording medium 4...Toner storage Hono J
? 6... Toner application roller 8... Recording electrode 9... Image signal voltage source ii
a, iib...Recording magnets 13a, 13b, 16-magnets Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] 1. A recording medium comprising a recording electrode array, a surface dielectric layer and a conductive layer that closely oppose and move relative to the recording electrode array, and a conductive magnetic layer on the surface of the recording medium. means for applying toner; means for applying a recording voltage according to an image pattern between a conductive layer of the recording medium and selected electrodes in the recording electrode array; and generating a magnetic field between the recording medium and the recording electrode array. In an image recording apparatus, the magnets are arranged to sandwich a recording electrode array so that the same poles face each other in order to clamp the recording medium, and the magnets direct a larger part of the magnetomotive force to the side opposite to the recording medium. An image recording device comprising: 2. The image recording apparatus according to claim 1, wherein the magnets include a pair of magnets located on the side of the recording medium and a pair of magnets with a larger magnetomotive force located on the side farther from the recording medium. 3. The image recording apparatus according to claim 1, comprising a pair of magnets whose thickness becomes thinner as the magnet is closer to the recording medium. 4. The image recording apparatus according to claim 1, wherein the magnets are comprised of a pair of magnets, and a magnet located between them that is adjacent to each other with the same polarity and has a larger magnetomotive force.