JPH04323050A - Image recording electrode - Google Patents

Abstract

PURPOSE:To optimize printing characteristics by specifying the cross section, shape and material of a recording electrode in an electrode supplying a current to the toner chain being in contact with a magnetic electrode needle to obtain a developed image. CONSTITUTION:In the comb tooth-shaped electrode in an image recording head consisting of an insulating substrate 1 and recording electrode needles 2..., in order to obtain printing characteristics good in black density, fog density and the resolving power of main scanning and sub-scanning lines, the cross section of the electrode is set to 8000/nmum<2> or more, pref., 9600/nmum<2> regardless of an electrode material. In the shape of a magnetic electrode, the thickness thereof is set to 15mum or more, pref., 20mum or more and the width thereof is set to 720/nmum or less, pref., 600/nmum or less. The material quality thereof is composed of a material having high magnetic permeability characteristics such as Ni or an Ni alloy such as an Ni-Fe alloy or Ni-Co alloy.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method of manufacturing a recording electrode for an image recording device, and particularly to an image recording device suitable for directly contacting conductive magnetic toner to obtain a high-resolution recorded image. concerning recording electrodes.

0002

2. Description of the Related Art Conventionally, various methods have been proposed in which a recording electrode is brought into direct contact with conductive magnetic toner and a voltage is applied to the recording electrode to obtain an arbitrary recorded image. The basic recording principles and configuration of this type of device are, for example:
It is described in Japanese Patent Publication No. 55-30228. In other words, this technology is different from the method that uses a photosensitive drum, which is the mainstream of current electrophotographic technology, to develop an electrostatic latent image with toner and transfer and record it onto recording paper. A recording method in which image information is directly formed as a toner image on a dielectric material without using a toner, and this is transferred to a recording medium, or it is directly formed on a recording medium made of a dielectric material.
This is also called the magnetic stylus recording method.

In order to implement this type of recording method, a large number of individual recording electrodes forming the pixel electrodes in FIG. requires a special image recording head.

0004

[Problems to be Solved by the Invention] This recording method uses magnetic force to form a toner chain in the gap between the magnetic recording electrode and the drum, and forms a developed image by passing current through the toner chain that contacts each magnetic electrode needle. do. For this reason, the material and cross-sectional shape of the recording electrodes that make up the image recording head are determined by the development density (density in the printed area) and fog density (density in areas other than the printed area).
, it is expected that printing characteristics (image quality) such as resolution of main scanning lines and sub-scanning lines will be greatly affected. However, until now, nothing has been clarified regarding the shape of each recording electrode constituting the image recording head to optimize the printing characteristics. Therefore, in order to actually create an electrode head, it was necessary to find a recording electrode shape that would optimize printing characteristics through trial and error, which required a great deal of time and effort.

An object of the present invention is to clarify the shape of a recording electrode that optimizes printing characteristics.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the inventors have developed a recording electrode formed of a magnetic material having high magnetic permeability such as Ni or a Ni alloy such as Ni-Fe or Ni-Co. As a result of studying the shape of the recording electrode that would optimize printing characteristics such as development density, fog density, and resolution of main and sub-scanning lines for the image recording head consisting of the following, the following knowledge was obtained. In addition, in order to draw a high-quality image, 1.
A resolution of about 8 dots per mm, that is, 8 recording electrodes per 1 mm, is required, and considering that this resolution has been increasing in recent years, various recording densities (1
The number of recording electrodes per mm was investigated.

[0007] The cross-sectional area of the electrode for developing a solid black density of 1.0 or more is 8000/nμm2 or more, preferably 9600/nμm2, regardless of the electrode material, at a gap of 50 to 150 μm between the electrode and the drum. That's all. n is the number of electrodes per 1 mm.

■Fog density The fog density is 0.1 or less regardless of the electrode material and cross-sectional shape.

(2) Resolution of main scanning line and sub-scanning line The shape of the magnetic electrode that provides good resolution is as follows, regardless of the material.

That is, main scanning line: electrode thickness of 15 μm or more, preferably 20 μm
Above, the electrode width is 720/nμm or less, preferably 600/nμm or less.
Sub-scanning line of nμm or less: electrode thickness of 15 μm or more, preferably 20 μm or more Summarizing the results, the optimum recording electrode dimensions for printing characteristics are as follows, regardless of the electrode material.

Cross-sectional area: 8000/nμm or more, preferably 9600/nμm or more Electrode thickness: 15μm or more, preferably 20μm or more Electrode width: 720/nμm or less, preferably 600/nμm or less When 8 and 16 recording electrodes are used, the results are shown in FIGS. 2 and 3.

0012

[Operation] The present invention provides black density (1.0 or more), fog density (0.1 or less), main scanning line/sub The optimum electrode shape for obtaining good printing characteristics such as scanning line resolution (MTF value of 0.3 or more) is shown. Therefore, when producing an image recording head, by designing recording electrodes according to the present invention, good printing characteristics can be obtained regardless of the material and recording density. This makes it possible to create an image recording head without spending the great amount of time and effort conventionally required to optimize printing characteristics.

[0013]

[Examples] Specific examples of the present invention will be shown below and explained in more detail. The image recording head used was created by the method shown below.

A Cr/Cu film with a thickness of 2 μm was formed as a plating base metal layer over the entire surface of the alumina substrate by sputtering.

Next, a photoresist pattern is formed on this in the same pattern as the recording electrode, and the underlying metal layer in the resist openings is removed by etching.

A dry film (PHT-145F-25, manufactured by Hitachi Chemical Co., Ltd.) having a photosensitive layer of 40 μm in thickness is pasted on the entire surface using a laminating device, and then, after development, it is selectively formed so that the recording electrode formation area becomes an opening. It was exposed and developed. Further, post-baking was performed at 120° C. for 30 minutes to form a resist pattern having a width of 65 μm, an interval of 60 μm, and a thickness of 35 μm.

[0017] Plasma ashing (300W, O2 pressure 0
．． 5 Torr) for 10 minutes to remove resist residue on the underlying metal layer that could not be completely removed by development.

A recording electrode of Ni--Fe was formed by electroplating.

The resist was removed by spraying methylene chloride to produce an image recording head having recording electrodes having this shape.

Regarding the printing characteristics, black density, fog density, and main and sub-scanning line resolutions (MTF values) were examined and were determined to be 1.0 or more, 0.1 or less, and 0.3, respectively.
If it is above, it is considered as good.

(Example 1) Image recording heads having 8 recording electrodes/mm with various cross-sectional shapes as shown in Table 1 were prepared. Ni-Fe was used as the material of the electrode. When their printing characteristics were evaluated, No. As in 2 to 4, cross-sectional area: 1000 μm or more, electrode thickness: 15 μm or more,
Good printing characteristics were obtained with an electrode width of 90 μm or less, a development density of 1.0 or more, a fog density of 0.1 or less, and an MTF value of 0.3 or more for both the main scanning line and the sub-scanning line.

Furthermore, when the cross-sectional area is 1200 μm or more, the electrode thickness is 20 μm or more, and the electrode width is 75 μm or less, the development density is 1.1 or more, and both the main scanning line and the sub-scanning line are MTF.
Even better printing characteristics with a value of 0.4 or more were obtained.

[0023]

[Table 1]

(Comparative Example 1) Same as Example 1, 8 pieces/mm
An image recording head having recording electrodes was created and its printing characteristics were evaluated. The thickness of the recording electrode is less than 15 μm (Table 1, No. 1) or the width is more than 90 μm (Table 1
, No. 5), the fog density was less than 0.1,
The development density and resolution were less than 1.0 and 0.3, respectively, and good printing characteristics could not be obtained. Furthermore, as the gap between the electrode and the developing drum widened, the developed density further decreased.

(Example 2) Same as Example 1, 8 lines/mm
An image recording head having recording electrodes was made of Ni--Co material, and its printing characteristics were evaluated (Table 1, No. 6). Also in this case, cross-sectional area: 1000 μm2 or more, electrode thickness:
Good printing characteristics were obtained with an electrode width of 15 μm or more and an electrode width of 90 μm or less.

(Example 3) Same as Example 1, 8 lines/mm
An image recording head having a recording electrode of 1 was made of Ni material, and its printing characteristics were evaluated (Table 1, Nos. 7 and 8). Also in this case, cross-sectional area: 1000 μm2 or more, electrode thickness: 1
Good printing characteristics were obtained with an electrode width of 5 μm or more and an electrode width of 90 μm or less.

(Example 4) Image recording heads having 16 recording electrodes/mm with various cross-sectional shapes as shown in Table 2 were prepared. Ni-Fe was used as the material of the electrode. When their printing characteristics were evaluated, No. As shown in 2 to 4, cross-sectional area: 500 μm or more, electrode thickness: 15 μm or more, electrode width:
45 μm or less, development density: 1.0 or more, fog density:
0.1 or less, MTF value for both main scanning line and sub-scanning line is 0.
Good printing characteristics of 3 or higher were obtained.

Furthermore, when the cross-sectional area is 600 μm or more, the electrode thickness is 20 μm or more, and the electrode width is 37.5 μm or less,
Development density: 1.1 or higher, both main and sub-scanning lines are MT
Even better printing characteristics with an F value of 0.4 or more were obtained.

[0029]

[Table 2]

(Comparative Example 2) Same as Example 4, 16 pieces/m
An image recording head with m recording electrodes was created and its printing characteristics were evaluated. The thickness of the recording electrode is less than 15 μm (Table 2, No. 1, 5) or the width is more than 45 μm (
Table 2, No. 1), the fog density was 0.1 or less, but the developed density and resolution were less than 1.0 and 0.3, respectively, and good printing characteristics could not be obtained.

[0031]

According to the present invention, an image recording head with good printing characteristics can be created by designing recording electrodes. This makes it possible to efficiently create an image recording head without spending the great amount of time and effort conventionally required to optimize printing characteristics.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a general image recording head;

[Fig. 2] The optimum electrode size range from the viewpoint of printing characteristics according to the present invention is 8.
A characteristic diagram illustrating a recording electrode of 1/mm,

[Figure 3]
FIG. 2 is a characteristic diagram illustrating the optimum electrode size range for a recording electrode of 16 lines/mm in terms of printing characteristics according to the present invention.

[Explanation of symbols]

1... Insulating substrate, 2... Recording electrode needle.

Claims (9)

[Claims] 1. An image recording head used in a recording method in which a toner chain is formed by magnetic force in the gap between a magnetic recording electrode and a drum, and a developed image is formed by passing current through the toner chain in contact with each magnetic electrode needle. A recording electrode, characterized in that the cross-sectional area of the n pieces/mm recording electrode constituting the recording electrode is 8000/nμm2 or more, preferably 9600/nμm2 or more. 2. According to claim 1, the thickness is 15 μm or more,
Preferably 20μm or more and electrode width of 720/nμm
Hereinafter, the recording electrode preferably has a diameter of 600/nμm or less. Claim 3: According to claim 1 or 2, the material is N.
A recording electrode having high magnetic permeability characteristics such as Ni or Ni alloy such as Ni-Fe or Ni-Co. 4. An image recording head comprising a recording electrode having the shape according to claim 1. 5. An image recording head comprising a recording electrode having the shape according to claim 2. 6. An image recording head comprising a recording electrode having the shape according to claim 3. 7. An image recording apparatus comprising an image recording head comprising recording electrodes having the shape according to claim 1. 8. An image recording apparatus comprising an image recording head comprising recording electrodes having the shape according to claim 2. 9. An image recording apparatus comprising an image recording head comprising recording electrodes having the shape according to claim 3.