JPH05107846A - Image recorder - Google Patents

Abstract

PURPOSE:To obtain an image recorder which is free from the occurrence of the stain of a recording head and the occurrence of tailing of a highly-resolved electrostatic latent image and is miniaturized, highly reliable and has high image quality by providing a heating layer which can be energized selectively as a recording medium. CONSTITUTION:As the recording medium 1, a medium provided with the heating layer which can be selectively energized is employed. The recording medium 1 itself is heated by selectively energizing the heating layer of the recording medium 1 by means of the recording head 10, thereby destaticizing it with heat. After the surface of the recording medium 1 is uniformly electrified, the heating layer of the recording medium 1 is energized by the recording head 10 according to image information and the energized part of the heating layer is heated in the form of a spot by the resistance. When the surface of the recording medium 1 is heated higher than the prescribed temperature by the heating of the heating layer thereafter, charges on the surface of the recording medium 1 are dispersed, so that heat destaticization is caused to form an electrostatic latent image on the surface of the recording medium 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus adopting an electrostatic recording system, and more particularly to a small-sized and highly reliable image recording apparatus.

[0002]

2. Description of the Related Art Conventionally, as this type of image recording apparatus,
For example, there is one disclosed in JP-A-59-37578. This uses a dielectric belt having a dielectric layer laminated on a conductive layer as a transfer medium, and a recording head such as a stylus head or an ion head is used to selectively charge the surface of the transfer medium according to an image signal. An electrostatic latent image is formed by applying or removing it. Then, the electrostatic latent image is developed with toner to form a toner image, and the toner image is transferred onto a transfer material to record the image.

However, in such an image recording apparatus, since the recording head is located on the surface side of the dielectric belt, the contamination of the recording head by the toner poses a problem, and the layout of the recording head and the developing device is examined, There is a problem in that it is necessary to consider the airflow to prevent the recording head from becoming dirty, which eventually leads to an increase in system size and cost. Further, since the electrostatic latent image is formed on the dielectric belt by the recording head located on the surface side of the dielectric belt, the fluctuation of the distance between the recording head and the dielectric belt directly affects the image quality, and the good image quality is obtained. There was also a problem that it was difficult to maintain.

As a means for solving such problems,
The one disclosed in JP-A-60-78463 has already been proposed. This is one in which the recording head is arranged on the back side of the dielectric belt. Heating is performed from the back side of the uniformly charged dielectric belt by the recording head according to the image information, and an electrostatic latent image is formed by thermal neutralization. The electrostatic latent image is formed on a dielectric belt, developed with toner, and then transferred and fixed on a transfer material.

[0005]

However, the above-mentioned prior art has the following problems. That is, in such a system, since the recording head is arranged on the back side of the dielectric belt, the problem of stains on the recording head due to toner is solved, but the recording head is heated from the back side of the dielectric belt. Therefore, there is a problem in that heat diffuses before the heat reaches the surface of the dielectric belt, and the resolution of the electrostatic latent image actually formed on the dielectric belt is reduced. Further, by the heat storage of the heating means such as a thermal head arranged on the back side of the dielectric belt,
There is a problem in that the area other than the area to be heated of the dielectric belt is also heated, and the trailing of the electrostatic latent image occurs.

[0006]

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art.
The purpose of this is not to say that the recording head is not contaminated, but it is of high resolution and does not cause tailing of the electrostatic latent image. The present invention is to provide an image recording device.

That is, according to the present invention, after the surface of the recording medium is uniformly charged, the uniformly charged recording medium is selectively heated according to image information to charge the surface of the recording medium. An electrostatic latent image is formed by thermally removing the generated charges, the electrostatic latent image formed on the recording medium is developed, and the developed image is transferred and fixed on a transfer material to record an image. In the image recording apparatus for performing the above, as the recording medium, one having a heat generating layer capable of being selectively energized is used, and by selectively energizing the heat generating layer of the recording medium, the recording medium itself is caused to generate heat and is subjected to thermal neutralization. Is configured to do.

As the recording head for energizing the recording medium, for example, an energizing stylus head is used.

Further, the structure of the above recording medium has a resin such as polyimide, polyaramid, polysulfone, polyimideamide, polyester-imide, polyphenylene oxide, poly-p-xylylene, polybenzimidazole or the like, as viewed from the head contact side. the binder resin containing the derivative, a conductive filler, such as carbon particles, metal powder, conductive ceramic powder, obtained by dispersing or dissolving the ionic conductive agent in the charge transfer complex or the like, a volume resistivity of 10 ^{0 -} 10 ² A heating layer controlled to Ω · cm, a metal such as aluminum, nickel, gold, silver, copper, platinum, or a conductive ceramic material such as RuO2 or TiN,
A conductive return electrode layer made of TaB2, CrB2, B4C, TiC, etc., a silicon-based resin, a polyimide-based resin,
The film is composed of at least three layers including an insulating recording layer made of a Teflon resin.

The recording layer preferably has a small thickness because it is necessary to efficiently remove charges on the surface of the recording layer by heat applied from the heat generating layer, but an electrostatic latent image is formed on the recording layer. Since it is formed, the layer thickness is determined in consideration of the charging property. Further, regarding the recording layer, the surface energy of the recording layer is 40 dyn because it is necessary to improve the peeling of the ink layer when the ink layer is transferred and fixed on the transfer material.
The es / cm is preferably 35 dynes / cm or less.

Further, as the charging means for charging the surface of the recording medium, it is sufficient that the recording layer can be uniformly charged, and a known means such as a scorotron may be used.

The developing means for developing the electrostatic latent image obtained on the recording medium may be known developing means for copying machines and the like.

The transfer / fixing unit is, for example, a current-carrying head.

As the transfer / fixing means in this case, a heat fixing roll, a thermal head or the like used in a usual electrophotographic apparatus can be used. However, it is necessary to select the method in consideration of the thermal efficiency at the time of transfer / fixing.

[0015]

According to the present invention, a recording medium having a heat generating layer capable of being selectively energized is used, and by selectively energizing the heat generating layer of the recording medium, the recording medium itself is heated to remove heat. Is configured to do. Therefore, after uniformly charging the surface of the recording medium, the recording head energizes the heating layer of the recording medium according to the image information, and the energized portion of the heating layer is spot-heated by the resistance. Next, when the surface of the recording medium is heated to a temperature equal to or higher than a predetermined temperature due to the heat generated by the heat generating layer, the electric charges existing on the surface of the recording medium are dispersed and thermally removed, and an electrostatic latent image is formed on the surface of the recording medium. An image will be formed. As described above, since the recording medium itself is heated to form an electrostatic latent image, the thermal efficiency is good, and since the heat diffusion is small, high-resolution image recording is possible. Further, since the recording medium itself is configured to generate heat, the heat accumulation of the recording head does not pose a problem as in the case where the recording medium is heated by another recording head, so that the trailing of the electrostatic latent image occurs. It is possible to obtain a high quality image from this point as well.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 1 shows an embodiment of an image recording apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a recording medium, which is formed as an endless belt.
Drive roller 2 and driven roller 3 having a large diameter and arranged in parallel with each other, and these drive roller 2 and driven roller 3
Is wound around the follower rollers 4 and 5 having a small diameter, which are arranged at a narrow distance below the arrow. As shown in FIG. 2, the recording medium 1 includes a heating layer 6 made of a carbon-dispersed polyimide resin having a volume resistivity of 10 ⁰ to 10 ² Ω · cm from the back side, a return electrode layer 7 made of aluminum, and silicon. The recording layer 8 is made of resin and the thickness of each of the layers 6, 7 and 8 is set to 20 μm, 0.2 μm and 3.5 μm, respectively.

A primary charger 9 for uniformly charging the surface of the recording medium 1 is provided on the surface of the upper portion of the recording medium 1 which is held horizontally. A scorotron is used as the primary charger 9, and the recording layer 8 of the recording medium 1 is uniformly charged to, for example, -200V.

Further, a recording head 10 for forming an electrostatic latent image is provided downstream of the primary charger 9 on the back surface of the upper portion of the recording medium 1 which is held horizontally.
As the recording head 10, for example, an energizing stylus head having a resolution of 8 dots / mm is used.
The recording head 10 energizes the heat generating layer 6 of the recording medium 1 in response to an image signal to cause the heat generating layer 6 to generate heat in accordance with the image signal, thereby heating the uniformly charged electric charge of the recording layer 8. The charge is removed to form an electrostatic latent image.

A developing device 11 for developing the electrostatic latent image formed on the surface of the recording medium 1 with toner is disposed on the side of the driven roller 3. The developing roll of the developing device 11 is driven by a magnet fixing / sleeve rotating method, and the rotating direction is the same as the moving direction of the recording medium 1. The developing bias applied to the developing sleeve of the developing device 11 is set to -150V, for example.

Here, the developer used in the developing device 11 is a two-component developer composed of toner and carrier,
The toner has an average particle size of 10μ obtained by mixing, pulverizing and classifying 90 parts by weight of polyester resin and 10 parts by weight of carbon black.
m, and 0.5 parts by weight of silica fine powder externally added to the above composition was used. The viscosity of this toner is 120 ℃
The viscosity was as low as 10 ⁴ poise. As the carrier, a ferrite powder having an average particle size of 50 μm and coated with polymethylmethacrylate was used. The toner concentration of the developer at this time was 8 wt /%.

On the other hand, a transfer fixing means for transferring and fixing the toner image formed on the surface of the recording medium 1 onto the transfer material is provided on the back surface of the lower portion of the recording medium 1 which is held horizontally. ing. As the transfer / fixing means, an energizing head 12 is used for uniformly heating the heat generating layer 8 of the recording medium 1 to uniformly generate heat in the heat generating layer 8 to melt-transfer the toner image. As the energizing head 12, a stylus head for energizing is used similarly to the recording head 10, but a high resolution like the recording head 10 is not required at all. This transfer / fixing unit is of a backside heating type in which the energizing head 12 is arranged inside the recording medium 1, and the linear velocity of the recording medium 1 is 40 mm in the direction of the arrow in FIG.
The energization is controlled by the control circuit so that the surface of the recording medium 1 becomes 150 ° C. when driven at / s.

Regarding the transferability of the toner image,
By controlling the surface energy of the recording layer of the recording medium, good transferability can be obtained, and a cleaner is unnecessary.

With the above structure, the image recording apparatus according to this embodiment records an image as follows. First, the surface of the recording layer 8 is thermally neutralized to about 0 V by heating the recording medium 1 by the transfer fixing unit. This static elimination is performed by energizing the heating layer 6 of the recording medium 1 entirely by the energizing head 12 and causing the heating layer 6 to generate heat. After that, the surface of the recording layer 8 of the recording medium 1 is set to −20 by the primary charger 9 as shown in FIG.
It is uniformly charged to 0V. Next, a current is applied from the back surface of the recording medium 1 to the portion corresponding to the image by the recording head 10,
By partially heating the heating layer 6 of the recording medium 1, as shown in FIG. 3, the charges on the recording layer 8 are dispersed to eliminate the electric potential of the image portion to approximately 0V. Thus, an electrostatic latent image having a background portion potential of −200 V and an image portion potential of 0 V is formed on the recording layer 8 of the recording medium 1. Then, the electrostatic latent image formed on the recording layer 8 of the recording medium 1 is developed by the developing device 11 to form a toner image on the recording layer 8.

The toner image thus formed is fused and fixed on the transfer material 15 by energizing the heat generating layer 6 of the recording medium 1 by the energizing head 12 in the transfer and fixing portion to heat the entire heat generating layer 6. To be done.

When an image was actually recorded on the transfer material 15 in this way, a good printed sample was obtained.
Further, when the printing test was carried out by repeating the above cycle, it was confirmed that stable image quality was obtained.

As described above, in this embodiment, the recording medium 1 is provided with the heat generating layer 6 which can be selectively energized, and the heat generating layer 6 of the recording medium 1 is selectively energized by the recording head 10. By doing so, the recording medium 1 itself is heated to remove heat. Therefore, after the surface of the recording medium 1 is uniformly charged, the recording head 10 energizes the heating layer 6 of the recording medium 1 in accordance with image information, and the energized portion of the heating layer 6 is spot-shaped by its resistance. After that, when the surface of the recording medium 1 is heated to a temperature equal to or higher than a predetermined temperature due to the heat generation of the heat generating layer 6, the electric charges existing on the surface of the recording medium 1 are dispersed and thermally removed, and the surface of the recording medium 1 is discharged. An electrostatic latent image will be formed on it. As described above, since the recording medium 1 itself is configured to generate heat to form an electrostatic latent image, thermal efficiency is good, and since heat diffusion is small, high-resolution image recording is possible. Further, since the recording medium 1 itself is configured to generate heat, the accumulation of heat in the recording head 10 does not pose a problem as in the case where the recording medium 1 is heated by another recording head. No pulling occurs and a high quality image can be obtained from this point as well.

Next, in FIG. 1, when the recording head 10 was replaced with a thermal head and a method of heating from the back side of the recording medium 1 was tried, a reduction in resolution due to thermal diffusion of the electrostatic latent image was observed. Further, when printing was repeated, trailing due to heat accumulation of the thermal head was also observed.

[0030]

According to the present invention, which has the above-described structure and operation, the recording head is not contaminated, and the electrostatic latent image is trailed with high resolution. It is possible to provide a compact, highly reliable, high-quality image recording device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image recording apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing a recording medium.

FIG. 3 is a graph showing an electrostatic latent image formed on the surface of a recording medium.

[Explanation of symbols]

1 recording medium, 6 heating layer, 7 return electrode layer, 8 recording layer, 9 primary charger, 10 recording head, 11 developing device, 12 energizing head

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/22 101 B 6830-2H 15/24 6830-2H 21/00 116 6605-2H

Claims (1)

[Claims] 1. After uniformly charging the surface of a recording medium,
An electrostatic latent image is formed on the recording medium by selectively heating the uniformly charged recording medium according to image information to thermally eliminate the electric charges charged on the surface of the recording medium. In an image recording apparatus for recording an image by developing the formed electrostatic latent image and transferring and fixing the developed image on a transfer material, a heating layer capable of selectively energizing is provided as the recording medium. An image recording apparatus characterized in that a recording medium itself is heated to remove heat by selectively energizing a heat generating layer of the recording medium.