JPH038544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct recording method in which a latent image forming step and a developing step are simultaneously performed on a recording medium, and more particularly to a direct recording method with improved retention of a powder image.

In recent years, in contrast to recording methods in which the latent image forming step and the developing step are separated, a direct recording method has been proposed in which the latent image forming step and the developing step are performed simultaneously. The configuration and recording principle of this direct recording method will be explained with reference to FIG. A recording electrode 1 formed by implanting a large number of needle-shaped electrodes and a cylindrical counter electrode 2 are arranged facing each other with a predetermined gap in between, and a sheet-shaped recording body 3 is placed on the recording electrode 1 in this gap. interpose in contact with. On the other hand, a magnetic and conductive toner 5 is supplied to the surface of the counter electrode 2 using a magnetic field from a rotating magnet 4 and other means. These constitute a magnetic brush forming means, and the tip of the magnetic brush made of toner 5 is brought into contact with the recording medium. In this state, when a voltage corresponding to the image signal is applied to the recording electrode 1 from the power supply 6, and the counter electrode 2 is grounded in potential or a bias voltage of the opposite polarity is applied, charges are injected into the toner 5. , attracts the electric field of the recording electrode 1 and adheres to the recording medium 3. At the same time, when the recording body 3 is moved at a constant speed in the direction of the arrow a, a toner image corresponding to the image signal is obtained on the surface of the recording body 3.

In the prior art described above, there is a method of directly recording using paper as the recording medium 3. Although this case has great advantages in terms of miniaturization and simplification of the device, it has the following drawbacks.

(1) Since the resistance value of paper is as low as 10 ¹⁰ to 10 ¹¹ Ωcm, the electric field caused by the recording electrode 1 spreads and the resolution does not improve.

(2) Paper has a small dielectric constant of 1.2 to 2.5, and its capacity is low, so a high recording voltage is required.

Therefore, in order to compensate for the above drawbacks, the paper thickness should be increased from 40 to
There are ways to make the paper as thin as 60 μm or to apply special processing to the paper, but either method limits the type and material of the recording paper, and it is not possible to record on ordinary plain paper. For this reason, the applicant has filed a patent application filed in
No. 64840 and the specification of Japanese Patent Application No. 54-64841 disclose a method in which an insulating film with a high resistance of 10 ¹² to ^{10 16} Ωcm is used as the recording medium 3, and a toner image is formed on the film and then transferred to plain paper. Proposed. The configuration of a recording apparatus using this method will be explained using FIG. 2. The recording body 3 is made of an insulating film in the form of a belt, and is rotated at a constant speed by cylinders 8, 9, and 10. A recording electrode 1 is installed inside this belt-shaped recording body 3 and brought into contact with the recording body 3. Further, a developing machine 11 having magnetic toner 5 on opposite sides of the recording electrode 1 and the recording medium 3 is installed, and the opposing electrode 2 is a sleeve of a developing roller. After forming a toner image on the recording medium 3 using the method described with reference to FIG. The toner image is transferred onto the recording paper 12 from the back side using a transfer corotron 13 or a transfer roller.
Thereafter, the toner image is fixed onto the recording paper 12 by the fixing roller 14. On the other hand, the recording body 3 is rotated further and the cleaning blade 1 removes the toner remaining after the transfer.
5, and the AC corona charge remover 16 erases the residual charge caused by the transfer action of the transfer corotron 13 on the recording medium 3, and the charge is used for repeated recording.

As described above, in this recording apparatus, a high-resistance, high-permittivity film can be used as the recording medium 3, so that relatively high image quality can be obtained in terms of resolution, and the recording voltage can also be lowered. Further, ordinary plain paper can be used as the recording paper.

In this proposal, the toner 5 adheres to the insulating film and is held by this adhesive force or frictional force, but if the adhesive force of the toner 5 is insufficient, the transfer Previously, there was a problem with toner disappearing from the film. In addition, when matrix driving is performed between the recording electrode 1 and the counter electrode 2, if the toner adhesion force is sufficient, there is a problem that toner will adhere even at a low voltage and that toner will adhere even at a half-selected point. It was hot. An object of the present invention is to provide a novel direct recording method that can sufficiently retain toner so that it does not disappear.

To achieve this objective, the direct recording method of the present invention:
A recording electrode and a magnetic brush forming means are disposed opposite to each other with a recording body interposed therebetween, and while the tip of a magnetic brush made of powder toner of the magnetic brush forming means is brought into contact with one surface of the recording body, a magnetic brush is formed between the recording electrode and the magnetic brush forming means. In the direct recording method, in which a toner image is formed on one surface of the recording medium by applying a voltage to the recording medium, the gap between the recording electrode and the magnetic brush forming means is maintained while maintaining a minute gap between the recording electrode and the recording medium. A gap discharge is generated between the recording electrode and the recording body by applying a voltage, and an electric charge is attached to the other surface of the recording body, and the powder toner of the magnetic brush forming means is held on one surface of the recording body by the electric charge. It is characterized by causing

Furthermore, in one embodiment of the present invention, in order to maintain a microgap between the recording electrode and the recording body,
The recording body is characterized in that unevenness is formed on the surface on the side of the recording electrode, and in another embodiment, the recording electrode is formed with an electrode needle in order to maintain a minute gap between the recording electrode and the recording body. It is characterized in that it is composed of a holding member, and the tip of the electrode needle is located at a position set back from the tip of the holding member.

That is, as a result of studying the use of an insulating film as the recording medium 3, the inventor came up with the following idea.

In order for the toner 5 to adhere to and be transported to the recording medium 3, the conventional different friction force or adhesive force alone is insufficient, and a reverse charge supplied from the recording electrode 1 is required. If this reverse charge does not adhere to the recording medium 3,
The toner 5 once attached to the recording medium 3 by the electric field is pulled back toward the counter electrode 2 by the magnetic field by the magnet 4 and the mechanical self-sweeping action of the toner 5 after the recording pulse voltage 6 ends. . In order to attach this reverse charge 7 to the recording medium 3, it is necessary to generate a gap discharge between the recording medium 3 and the recording electrode 1. When a gap discharge occurs, the opposite charges inside the recording electrode 1 move through the gap and adhere to the recording medium 3.
This process will be explained using FIG. 3, which is a diagram illustrating the principle of the present invention.

In FIG. 3, the voltage applied between the recording electrode 1 and the counter electrode 2 is V ₀ , the thicknesses and dielectric constants of the recording body 3 and the toner layer 5 are ds, dt, ε _S , εt, respectively, and the recording electrode 1 and the counter electrode 2 are If the gap distance of the recording medium 3 is g, then the voltage Vg applied to the gap can be found from the following relationship.

Vg=V ₀ ·g/dt/εt+d _S /ε _S +g When this gap voltage Vg exceeds the gap discharge voltage of Patsien, a gap discharge occurs and the charge 7 moves and adheres to the recording medium 3. If the relationship between the gap distance g and the discharge starting voltage V ₀ is expressed in a graph, it will be as shown in the gap vs. discharge starting voltage characteristic diagram in FIG.

As can be seen from FIG. 4, it is necessary to maintain an appropriate gap distance g in order to start discharge at a low applied voltage V ₀ . That is, if the gap distance g is very narrow and the recording electrode 1 and the recording medium 3 are in close contact with each other, gap discharge is unlikely to occur, and if the gap distance g is too large, gap discharge is also unlikely to occur. That is, in order to cause proper gap discharge, it is necessary to maintain the gap distance g at 5 to 15 μm. or,
Since such a gap discharge has a threshold voltage (discharge starting voltage), matrix driving is possible.

The present invention will be explained below using examples.

In one embodiment of the present invention based on this idea,
Furthermore, the gap distance g between the recording electrode 1 and the recording body 3 is
As a means for maintaining the recording body 3 at a constant minute distance even during rotation of the recording body 3, irregularities are provided on the surface of the recording body 3 on the side where the recording electrode 1 contacts, so that stable air gap discharge occurs. Facilitates image formation.

FIG. 5 is a configuration diagram of an embodiment of a recording medium used in an embodiment of the present invention. The recording body 3 is a base material layer 3
1 and an uneven layer 32. The base material layer 31 may be an insulating film made of a polymeric material such as polyester, polyethylene, polyvinyl chloride tetrafluoroethylene, polypropylene, etc., and has a resistance value of 10 ^{to 12.}
A film of ~10 ¹⁶ Ω-cm is desirable. Also, the thinner the thickness, the better the resolution, but considering the tensile strength when made into a belt, it is 25 ~
A thickness of 50 μm is desirable. The means for forming an uneven layer on the surface of the base material layer 31 is to apply calcium carbonate glass powder (average particle size 8 to 15 μm) 33 to an insulating resin such as unsaturated polyester, acrylic, or epoxy.
Mix and separate the mixture and apply with a blade. When the dry film thickness d is 5 to 15 μm, a recording medium 3 having an uneven surface suitable for air gap discharge can be obtained. Alternatively, the recording medium 3 may be formed by directly roughening the base layer 31 itself mechanically with a file or the like to form an uneven surface.

FIG. 6 is a configuration diagram of an embodiment of the present invention.

While bringing the uneven surface of the recording medium 3 into contact with the recording electrode 1, the recording medium 3 is fed at a constant speed in the direction of arrow a. At this time, the toner 5 is in the first position with respect to the counter electrode 2.
It is held by the means shown in the figure. Recording electrode 1
When a voltage 6 corresponding to the image signal is applied to the recording voltage 6, as described using the principle diagram in FIG. The reverse charge 7 attracts the toner 5 and adheres to the uneven surface of the recording medium 3. The recording voltage V ₀ at this time is 25 to 50 μm in thickness of the recording medium 3.
When this happens, image formation is possible at 700 to 900V.

As described above, according to this embodiment, the recording medium 3
The gap distance g can be maintained by a simpler method of simply forming an uneven surface on the surface, and this allows charge to be attached by gap discharge, allowing stable image formation at a low voltage, resulting in improved performance. This has the effect of improving both costs.

Next, other embodiments of the present invention will be described.

In another embodiment of the present invention, the recording electrode 1 is provided as a means for maintaining the gap distance g between the recording electrode 1 and the recording body 3 in FIG. When a step is provided by a minute distance between the electrode needle and the holding member at the tip of the recording electrode 1 and the recording body 3 are brought into contact, the distance between the tip of the electrode needle and the recording body is maintained with a minute gap. This is how it was done.

FIG. 7 is an example configuration diagram of a recording electrode in another embodiment of the present invention. Note that FIG. 7a is a longitudinal cross-sectional view thereof, and FIG. 7b is a cross-sectional view thereof.

The recording electrode 1 is made up of a plurality of electrode needles 11 arranged at equal intervals and fixed with a holding member 12. Copper wire, phosphor bronze wire, nickel wire, etc. are used as the material for this electrode needle, and the holding member is made of insulating and moldable resin material, such as epoxy, methacrylic, phenol, ethylene tetrafluoride, etc. Quartz powder is sometimes mixed in to increase strength. A plurality of electrode needles 1 are attached to the tip of the holding member 12.
An effective method for uniformly forming steps at the tips of the recording electrodes 1 at intervals g is to immerse the recording electrodes 1 in a liquid that corrodes the electrode needles 11 for a certain period of time to etch them.

As an example, when the electrode needle 11 has a phosphor bronze wire diameter of 80 μm, when it is immersed in a nitric acid solution for about 15 seconds and then washed, the tip of the electrode needle is etched by 10 μm to 12 μm, and a cylindrical shape is formed between it and the holding member 12. A hole will form.
Using the recording electrode 1 manufactured in this way, the second
In the recording apparatus shown in the figure, when recording is performed, even if the recording electrode 1 and the recording medium 3 are held in close contact with each other, a certain gap g always exists between the recording electrode 1 and the electrode needle 11, so that discharge is likely to occur. Thickness as recording body 3
700~ when using 25μm polyester film
Good image formation was achieved with an applied voltage of 900V.

FIG. 8 is a configuration diagram of another example of the recording electrode according to another embodiment of the present invention. As a method of maintaining the gap between the recording electrode needles, the tip of the recording electrode 1 is machined to hold the electrode needle 11. Step 13 between members 12
This is an example where . Incidentally, FIG. 8a is a longitudinal cross-sectional view thereof, and FIG. 8b is a cross-sectional view thereof.

There is a gap g at the tip of the recording electrode 1 except for the electrode needle 11.
It is also possible to attach a member with a thickness of .

As described above, according to this embodiment, a simpler method of etching the tip of the recording electrode can be used.
Since the gap distance g can be maintained and stable image formation can be performed with a low voltage, both performance and cost are improved in the recording apparatus shown in FIG.

As described above, according to the present invention, a minute gap is maintained between the recording electrode and the recording body, a gap discharge is generated, and the resulting charge is attached to the recording body to retain the toner, thereby toner A stable image can be obtained without image disappearance. Furthermore, matrix drive is also possible. Furthermore, although it is possible to generate electric charge without maintaining a microgap, this requires a high voltage.In comparison, the present invention allows electric charge to be generated at a low voltage due to air gap discharge. You also get benefits.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the conventional direct recording method, Fig. 2 is a block diagram of the previously proposed device, Fig. 3 is a principle diagram of the recording part of the present invention, Fig. 4 is a relationship diagram in the principle of the present invention, FIG. 5 is a block diagram of an example of a recording body used in an embodiment of the present invention, FIG. 6 is a block diagram of an embodiment of the present invention, and FIG. 7 is a block diagram of an example of a recording electrode in another embodiment of the present invention. , FIG. 8 shows another example configuration diagram of a recording electrode in another embodiment of the present invention. The symbols in the figure indicate the following. DESCRIPTION OF SYMBOLS 1... Recording electrode, 2... Counter electrode, 3... Recording body, 4... Rotating magnet, 5... Toner, 6... Power source, 7... Reverse charge, 8, 9, 10,... Cylinder, 11...Developing machine, 12...Recording paper, 13...
Transfer corotron, 14... Fixing roller, 15...
Cleaning blade, 16... AC corona static eliminator, 31... Base material layer, 32... Uneven layer, 11...
Recording needle, 12...holding member.

Claims (1)

[Scope of Claims] 1. A recording electrode and a magnetic brush forming means are disposed facing each other with an insulating recording member interposed therebetween, and while the tip of the magnetic brush made of powder toner of the magnetic brush forming means is in contact with one surface of the recording member, In a direct recording method in which a toner image is formed on one surface of the recording medium by applying a voltage between the recording electrode and the magnetic brush forming means, while maintaining a microscopic space between the recording electrode and the recording medium. By applying a voltage between the recording electrode and the magnetic brush forming means, a space discharge is generated between the recording electrode and the recording body, and an electric charge is attached to the other surface of the recording body, and the magnetic brush is caused by the electric charge to adhere to the other surface of the recording body. A direct recording method characterized in that powder toner of a brush forming means is adsorbed and held on one surface of the recording medium. 2. A microscopic space is formed between the recording electrode and the recording body.
Claim 1, characterized in that the surface of the recording body on the side of the recording electrode is formed with unevenness in order to maintain the
Direct recording method as described in section. 3. In order to maintain a microscopic space between the recording electrode and the recording body, the recording electrode is composed of an electrode needle and a holding member, and the tip of the electrode needle is located at a position set back from the tip of the holding member. A direct recording method according to claim 1, characterized in that: