JPS59133075A - Electrostatic recording head - Google Patents

Abstract

PURPOSE:To make it possible to prevent the lowering in recording density by suppressing the surface change of a recording electrode, by coating the part of the head surface of a multi-needle recording electrode array, which forms an electrostatic image to a recording body, exposed from a head surface with a corrosion resistant material. CONSTITUTION:An electrostatic recording head is constituted of multi-needle electrodes 3 arranged so as to provide air gaps 2 each for performing corona discharge with respect to a recording body, control electrodes 4 arranged to both sides thereof at a predetermined interval, a gold plating layer 11 formed to the surface of each electrode 4 and an insulating spacer 12. Each needle electrode 3 comprises a nickel wire with a thickness of 50 mumphi and a gold plating layer 10 with a thickness of about 5mum is applied to the part thereof exposed to the air gap 2 in opposed relation to the recording body. By this method, because gold plating treatment is applied to the discharge surface of each electrode, oxidation or surface deterioration is not generated even if the recording electrode is used for a long period of time and, therefore, stable discharge can be stably performed while the lowering in recording density can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to an electrostatic recording head that suppresses changes in the surface of recording electrodes to prevent a decrease in recording density.

(2) Prior Art A conventional electrostatic recording head, for example, as shown in FIG. A multi-needle electrode (discharge electrode) 3 is arranged with an air gap 2 for causing corona discharge to the recording medium 1 (for example, a dielectric belt, a drum, etc.), and a
control electrodes 4 which are arranged at a predetermined interval (with respect to the moving direction of It is composed of a spacer 5 provided on the surface of the control electrode 4 and a resin mold 6 for fixing each electrode.

In the above configuration, a pulse voltage (for example, -300■) is applied to the multi-needle electrode 3 in accordance with the recorded information on a line-by-line basis, while the control electrode 4 has a polarity opposite to that of the voltage applied to the multi-needle electrode 3. voltage (for example, +350V) is applied. Usually, in order to simplify the drive circuit, electrodes are grouped and voltage is applied at predetermined timing. When there is recorded information, the sum of the voltage of the multi-needle electrode 3 and the voltage of the control electrode 4 (750V) is applied within the air gap 2, corona discharge is generated in the recording body 1, and the voltage applied within the multi-needle electrode 3 is applied. An electrostatic latent image is formed based on the electrodes.

However, in conventional electrostatic recording heads, due to long-term use, the multi-needle electrode 3 oxidizes in the discharge atmosphere and the surface becomes rough due to discharge, resulting in deterioration of corona discharge characteristics and recording. There was a phenomenon that the concentration decreased.

(3) Object and structure of the invention The present invention has been made in view of the above, and in order to prevent a decrease in recording density due to surface changes, the exposed portion of the multi-needle electrode from the head surface is coated with a corrosion-resistant metal. The present invention provides an electrostatic recording head as described above.

(4) Examples The electrostatic recording head according to the present invention will be explained in detail below.

FIGS. 2(a) and 2(b) show an embodiment of the present invention;
The same parts as in the figures are indicated by the same reference numerals, so redundant explanations will be omitted, but gold plating 10 and 11 (instead of gold, platinum, The structure differs from that of FIG. 1 in that it uses tungsten (tungsten or the like may also be used).

As for the processing, when a nickel wire of 50 μmφ is used for the needle electrode, the thickness of the gold plating 10 is set to about 5 μm, and the required number of wires are arranged in a line at a density of 12 wires/l+II+1. As the control electrode 4, a 5 μm thick gold plating 1 is formed on the opposite surface of the recording medium 1 made of a 4×4wn phosphor copper plate.
1, a Teflon-based resin is spray applied to the electrode surface to a thickness of 8 μm, excluding the air gap 2, to form an insulating spacer 12. In addition, each electrode shall be polished before gold plating. The recording medium 1 is, for example, a three-layered material in which a 20 μm thick low resistance layer (107Ω/hole) is formed on a 75 μm thick PET film, and a 6 μm thick dielectric layer (PET film) is formed on top of this. A structured dielectric belt can be used.

In the above configuration, a pulse voltage of, for example, -300V is applied to the multi-needle electrode 3 provided with the gold plating 10 according to recorded information, and the control electrode provided adjacent to the needle electrode symmetrical with this drive 4, for example +350v
A pulse voltage of is applied. The application time of these applied voltages is about 15 μs. As a result, 700V is applied to the surface of the recording medium directly under the multi-needle electrode 3, and an electrostatic latent image is formed depending on the charging state. Since the discharge surface of each electrode is gold-plated, there is no risk of oxidation or surface deterioration even during long-term use.

In the above embodiment, an example was shown in which the control electrode was also plated with gold in addition to the multi-needle electrode, but the effects of the present invention are not impaired even if only the multi-needle electrode is plated with gold. Further, the present invention can also be applied to a back surface control method in which the control electrode is provided on the back surface of the recording electrode.

FIG. 3 shows the electrostatic recording head 100 of the present invention shown in FIG.
This is a system in which an electrostatic recording head 100 according to the present invention is used to form an electrostatic latent image on a recording medium formed on the surface of an endless belt. A recording body belt 21 on which the recording body 1 described above is formed, an electrostatic recording head 100 in which the recording body belt 21 and the spacer 5 are provided so as to be able to come into contact with each other, and a recording body belt 2
1, a motor 23 that drives the row 222, a developing device 24 that attaches toner to the surface of the recording belt 21 according to the surface charge, and a roller 222 that drives the recording belt 21.
A transfer corotron 26 that attaches (transfers) the toner attached to the surface of the belt 21 to the recording paper (plain paper) 25; a cleaner 27 that removes the toner attached to the surface of the belt 21 after the transfer is completed; an erase corotron 28 for removing electric charge from the cleaned recording belt 21;
A fixing device 2 that fixes the print or image transferred to the recording paper 25
9 and a recording belt 2 sent to the electrostatic recording head 100.
A precharge corotron 3o that uniformizes the charged state of the surface of the electrode 1, a drive circuit 31 that applies a recording voltage to the multi-needle electrode 3 and a bias voltage to the control electrode 4, and a drive circuit 31 and a row 222. It is also configured with a control section 32 that controls the motor 23 to be driven.

In the above configuration, for example, the drive circuit 31 and the electrostatic recording head 100 are
When a recording voltage is applied to the multi-needle electrode 3, an electrostatic latent image is formed on the surface as the motor 23 driven by the control section 32 rotates the precharged dielectric belt 21. This latent image is developed with toner by a developing device 24 and transferred onto a recording paper 25 by a transfer corotron 26. The transferred toner image is fixed by a fixing device 29 to obtain a recorded image. On the other hand, the recording belt 21 is cleaned by the erase corotron 28 after the remaining I/N is removed by the cleaner 27.
The latent image is erased.

(5) Effects of the invention When a conventional electrostatic recording head is used in such a recording device, surface deterioration occurs due to oxidation or discharge after printing 300 sheets/A4 or after one month, and the print density becomes normal. It has fallen to about 70% of the previous year. However, when the electrostatic recording head of the present invention was used, the print density after 20,000 sheets/A4 paper or 4 months was 90 cm compared to normal, and a significant improvement in performance was observed.

According to the electrostatic recording head of the present invention as explained above,
Since at least the surface of the multi-needle electrode facing the recording medium is coated with a corrosion-resistant metal, a decrease in recording density (print density) can be prevented by suppressing changes in the surface of the recording electrode.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional electrostatic recording head, Figure 2 (A)
, (b) shows an embodiment of the present invention, (a) is a cross-sectional view,
(B) is an enlarged view of the recording electrode covered part of 0). FIG. 3 is a configuration diagram showing an example of a recording apparatus using the electrostatic recording head of the present invention. Explanation of symbols 3...Multi-needle electrode, 4...Control electrode, 6...
Resin molding)', 10.11...Gold plating,
12...Spacer. Patent Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Nobuyuki Matsubara Same as Seishunma Muraki Same as above 1) Yudo Tadashi Same as above
Jun Shima - Same Suzuki
Figure 1 Figure 2 (season ω)

Claims (1)

[Scope of Claims] Column multi-needle recording electrodes that are applied with a voltage according to recorded information to form an electrostatic latent image on a recording medium row by row, and control in which a bias voltage is applied to both sides of the recording electrodes. An electrostatic recording head comprising an electrode, characterized in that an exposed portion of the recording electrode from the head surface is coated with a corrosion-resistant material.