JPS60260350A - Image recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible to obtain density free from fogging and resolving power, in a toner system image recording apparatus, by intensifying the magnetic field due to a magnet at the time of the non-application of recording voltage to a recording electrode as compared with that at the time of the application thereof by a pulse magnetic field generation means. CONSTITUTION:When no signal voltage is applied to a recording electrode 7, toner T receives force in a D-direction by the movement of a recording medium 1 in an A-direction but a magnet 7 flows a current to a coil 14 from a pulse power source 12 so that the directional magnetic flux intensifying the magnetic flux at the leading end of the electrode is generated from a magnetic material 13 and magnetical restricting force is acted on the toner T to prevent the unnecessary toner T from flowing out to the downstream side of the electrode 7 and the fogging of an image is prevented. At the time of the application of signal voltage, no current is flowed to the coil 14 and the restricting force to the toner T at the leading end of the recording electrode 7 is weakened and, at this time, the toner T is adhered to the recording medium 1 by the voltage applied to the recording electrode 7 from a character signal generator and a sharp image is obtained.

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 conductive magnetic developer (hereinafter abbreviated as toner) to a recording medium in response to an image electrical signal. The present invention relates to an image recording device that records images.

[Background of the invention]

This type of device is described in detail in U.S. Pat. A very general outline of this conventional device will be explained with reference to FIG.

In FIG. 2, reference numeral 1 denotes a recording medium, which in this example has a structure in which alumite-treated dielectric layers 1 and b are provided on an aluminum cylinder 1a, but it is an electrostatic recording medium that is usually commercially available and is insulated. etc. can also be used. 2 is a hollow roller for storing conductive magnetic toner Tk, and inside is a hollow cylindrical toner application roller 4 made of a non-magnetic conductor.
A rolled magnet 3 is housed inside the magnet. Reference numeral 7 denotes a recording electrode, which is usually made of a magnetic material such as iron, permalloy, nickel, etc., and is made by arranging a large number of thin wires facing the recording medium 1 in parallel to the axial direction, or by a technique such as etching technique. .

Although not shown, they are electrically insulated from each other and fixed together using an insulating adhesive. The recording electrode 7 is held between magnets 8 having the same polarity and facing each other. Further, each of the recording electrodes 7 is independently connected to a character signal generator 9.

The recording medium 1 rotates in the direction indicated by the arrow. ) When the toner application roller 4 rotates in the direction of arrow B, the toner T in the toner application roller 4 is attracted to the toner application roller 4 by the action of the magnet 3, and a uniform toner T is applied by the doctor blade 5.
is formed on the application roller 4. When this toner T is carried by the rotation of the application roller 4 and comes into contact with the recording medium 1, it acquires all the electrostatic charge due to the application of a DC voltage from the bias power supply 6 and adheres to the recording medium 1.

By the time the toner T reaches the recording position 10 as the recording medium 1 rotates in the direction indicated by the arrow, most of the electrostatic charge has been lost and Q) the particles are attached to the recording medium and the recording When reaching position 10, the magnetic field emitted from the magnet 8 affects the recording electrode T, forming a spike of toner T spanning between the recording medium 1 and the recording electrode 7, and the remaining static charge escapes through this spike. Particularly, at this time, the toner has almost lost its adhesion to the recording medium 1. However, when a recording signal voltage corresponding to the image pattern is applied from the character signal generator 9 at this time, the toner T formed between the recording electrode 7 and the recording medium 1 is transmitted through the ears and mutually sandwiched between the dielectric layer 1b. Charges of opposite polarity appear on the conductive layer 1a and the tips of the ears of toner T.

This charge provides sufficient electrostatic force to adhere the toner Tt to the recording medium l. On the other hand, in the area where the recording signal voltage is not applied (non-image area), there is no charge injection as described above, so no electric force acts between the recording medium l and the toner 1, so the toner T in that area is transferred from the magnet 8. A small amount of the generated magnetic field is transmitted to the recording electrode 7 and accumulated near the magnet 8.

As a result, a visualized toner image is formed on the recording medium 1 that has passed through the recording position 10 facing the recording electrode 7.

Although not shown, this toner image is usually transferred to paper and fixed by electric discharge or pressure transfer, or if electrostatic recording paper or the like is used as the recording medium 1, it may be fixed as is. .

3A and 3B are enlarged views of the vicinity of the recording position 10 in order to explain the operation of the apparatus of FIG. 2 in more detail. Third
Figure A shows a case where a recording signal voltage is applied, and Figure 3B shows a case where a recording signal voltage is not applied. The broken line shows how the magnetic field generated by the magnet 8 passes near the recording electrode 7.

When a signal voltage is applied from the character signal generator 9 between the recording medium 1 and the recording electrode 7 as shown in FIG. 3A, the toner T adheres to the recording medium 1 and flows against the magnetic force of the magnetic field 10. Attach as described above.

However, as shown in FIG. 3B, if the signal voltage is not applied to the recording electrode 7 from the character signal generator 9, the recording medium 1 and the toner 1
Since no adhesive force acts between them, the toner TU moves in the direction of arrow C by the magnetic force of the magnetic field (broken line) generated by the magnet 8. As a result, a visualized toner image appears on the recording medium 1.

However, in the above-mentioned apparatus, depending on the strength of the magnetic force of the magnet 8, there is a possibility that the recorded image density may decrease or fog may occur. According to the inventor's experiments, a good image quality with uniform density without fog could not be obtained unless the magnetic flux density at the tip of the recording electrode 7 was set to 1000-1300 Gauss. Moreover, due to ambient temperature and humidity, toner variations, etc.
Since the optimum value of the magnetic flux density mentioned above also changes, it is difficult to adjust the magnetic force, so it is difficult to adjust the magnetic force. For this reason, the apparatus becomes larger and the image density decreases, making it impractical.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks in an image recording apparatus of the above-mentioned type, and to enable the formation of fog-free images with good density and resolution.

[Summary of the invention]

The present invention provides a recording electrode array, a recording medium comprising a surface galvanic layer and a conductive layer that closely oppose and move relative to the tip of the recording electrode array, and a nuclear recording medium surface and a recording electrode layer. means for supplying all of the conductive magnetic toner between the recording medium, means for applying a recording voltage according to an image pattern between the conductive layer of the recording medium and selected electrodes in the recording electrode array; In an image recording device including a magnet that generates a magnetic field sound between a medium and a tip of a recording electrode array,
A pulsed magnetic field generating means is provided which sandwiches the recording medium and faces the recording electrode array, and the pulsed magnetic field generating means makes the magnetic field generated by the magnet stronger when the recording voltage is not applied to the recording electrodes than when the recording voltage is not applied. It is characterized by this.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the invention. In the figure, parts similar to those in FIGS. 2 and 3 are designated by the same numbers. As the recording medium 1, a cylinder made of aluminum with a diameter of 100 cm is used as the conductive layer 1a, and the surface of this aluminum cylinder is further coated with a thickness of 2 μm.
The insulating layer 1b was formed by processing thick alumite. Toner T can be used as long as it is about 1010 Ω-m or less and contains magnetism, but in this example, imaging powder VQC3 sold by 3M Company was used.
The one adjusted to 55 was used. Recording electrode 7 has a diameter of 20
A total of 3,360 pieces of μm pure iron were carried across a width of 210 mm, each of which was electrically insulated independently and solidified with an insulating material 11 made of Cemedine High Super (trade name). . The fixed recording electrode group 7 faces the recording medium 1 so as to be substantially perpendicular to the recording medium 1 with a gap of 75±25 μm. As shown in FIG. 1, the magnets 8 are arranged so that the recording electrode group 7 is sandwiched therebetween, and the same poles face each other so that the magnetic flux density at the recording position of the recording electrode 7 is high. If the magnetic flux density of the magnet 8 alone is sufficiently high, the magnet may be provided only on one side.

Reference numeral 12 denotes a voltage generating power source, and a coil 14 is wound around a magnetic material 13, and this coil 14 is connected to the pulse power source 12. The magnetic material 13 is placed within the recording medium 1 across the entire width of the recording electrode group 7 to face it. 200mm/sec (Df
ffJx t −)'T@に'@<, 1 car. After the toner Te is uniformly deposited on the recording medium using the cloth roller 4, when the recording position 10 is reached, an image signal voltage of about 30 V corresponding to the image pattern is applied to the recording electrode 7 by the character signal generator 9. By applying this, image recording is performed as explained in FIG.

By the way, as explained with reference to FIGS. 2 and 3, conventional methods have been unsatisfactory in terms of image fog and density.

Therefore, in the present embodiment shown in FIG. 1, when the signal voltage from the character signal generator 9 is applied to the recording electrode 7,
A noggle current k is caused to flow from the pulse power source 12 to the coil 14 so that a magnetic flux fully magnetic material 13 is generated that weakens the magnetic flux created by the magnet 8 at the tip of the recording electrode 7. Alternatively, when the signal voltage from the character signal generator 9 is applied to the recording electrode 7, no current is caused to flow through the coil 14 at all. However, it is better to do the latter in order to obtain clearer images with better resolution. Also, when the signal voltage from the character signal generator 9 is not applied to the recording electrode 7.

In this case, an A pulse current is caused to flow through the coil 14 so that a magnetic flux is generated from the magnetic material 13 to strengthen the magnetic flux created by the magnet 8 at the tip of the recording electrode 7.

It has been confirmed that by doing this, unnecessary toner does not flow onto the recording medium 1 downstream of the recording position 10, and it is possible to prevent fog from occurring, and the magnetic flux density at the tip of the recording electrode 7 is maintained as before. 1000-1300 Gauss is not necessary (it has been confirmed that it is possible to obtain very clear and fog-free images with about 200-1000 Gauss).

In this embodiment, the magnetic flux at the tip of the recording electrode 7 is set to 450 Gauss, and the magnetic material 13 is placed slightly closer to the toner application side instead of facing directly in front of the tip of the recording electrode 7. It turns out that there is.

FIGS. 4A and 4B are views explaining in detail all the functions of the embodiment shown in FIG. 1.

FIG. 4A shows the state when no signal voltage is applied to the recording electrode 7. As the recording medium 1 moves in the direction of the arrow, a force is exerted on the toner TK in the direction of the arrow, but the magnetic flux from the magnetic material 13 in the direction of strengthening the magnetic flux created by the magnet 8 at the tip of the electrode 7 is A current is passed through the coil 14 from the pulse power supply 12 to generate the recording electrode 7.
At the tip of the recording electrode 7, the magnetic fields emitted from the magnet 8 and the magnetic material 13d) combine to exert a strong magnetic binding force on the toner T, so that unnecessary toner does not flow downstream from the recording electrode 7.
Therefore, the occurrence of image fogging is prevented.

On the other hand, FIG. 4B shows the state when a signal voltage is being applied to the recording electrode 7. At this time, no current is allowed to flow through the coil 14 (although it is possible to flow a current in the opposite direction to that shown in FIG. 4A, it is better not to flow it as described above). As a result, the magnetic field at the tip of the recording electrode 7 is
9) The binding force on the toner T is weakened, but at this time, the character signal generator 9 applies voltage to the recording electrode 7, so the toner T is
adheres to the recording medium 1. In this case, the conventional recording electrode 7
Since the magnetic force from is weaker than in the case of FIG. 2, the toner T is restrained weakly and the recording density increases.

Furthermore, since the magnetic field from the recording electrode 7 is concentrated on the magnetic material 13, it is possible to obtain a clearer image than ever before.

Next, when the signal voltage is no longer applied to the recording electrode 7 from the character signal generator 9, current is applied from the pulse power source 12 to the coil 14 as shown in FIG. 4A, and a strong magnetic field is immediately applied to the recording electrode 7 again. The unnecessary toner T that was formed at the tip and did not contribute to recording is trapped between the recording medium 1 and the recording electrode 7, so it does not flow downstream and adhere to the recording medium 1, thereby preventing fogging. etc. will not occur.

Note that the magnetic material 13 may be divided into as many parts as the number of recording electrodes 7 and each part may be independently excited and driven.

FIG. 5 is a block diagram of the electrical circuit used in the embodiment described in FIGS. 1 and 4 above.

The detector 15 performs QOR detection of the signal from the character signal generator 9 to the recording electrode 7, and provides a signal to the pulse voltage generator 12 to generate the magnetic field from the magnetic material 13 as shown in FIG. 4B.

As a modification, a better effect can be obtained by shaping the magnetic material 13 so that its end facing the tip of the recording electrode 7 is bent toward the toner inflow side.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent the fogging density of recorded images and to make the magnet smaller and weaker than before, and the image density can be increased without the need for a complicated fog removing device. In addition, it is possible to reduce the size of the device.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a sectional view of a conventional image recording device, Figs. 3A and 3B are partially enlarged views for explaining the entire operation thereof, and Figs. FIG. 4B is a partially enlarged view for explaining the operation of the embodiment shown in FIG. 1, and FIG. 5 is an illustrative diagram of an electric circuit used in the embodiment. 1... Recording medium 3... Roll magnet 4... Toner application roller 6... DC power supply 7... Recording electrode 8
...Magnet 9...Character signal generator 10...Recording position 12...
・Pulse voltage generator 13...Magnetic material 14...Coil 15...Detector T...Toner Figure 1 12 Figure 4A Figure 5] Go to 14

Claims (1)

[Claims] A recording medium consisting of a recording electrode array, a surface dielectric layer and a conductive layer that closely face and move relative to the tip of the recording electrode layer, and a conductive magnetic layer between the recording medium surface and the recording electrode array. means for supplying toner; means for applying a recording voltage according to an image pattern between the conductive layer of the recording medium and selected electrodes in the recording electrode array; and between the recording medium and the tip of the recording electrode array. A magnet for generating a magnetic field, and a pulsed magnetic field generating means facing the recording electrode array sandwiching the recording medium in an image recording apparatus that is fully equipped,
An image recording apparatus characterized in that the pulsed magnetic field generating means makes the magnetic field based on the magnet stronger when the recording voltage is not applied to the recording electrode than when the recording voltage is not applied.