JPS6027982B2 - Non-impact recording device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a non-impact recording device.

A counter electrode whose surface is uniformly covered with powder toner is placed opposite the recording electrode across a predetermined gap, a recording sheet is interposed in the gap, and an image signal is applied to the recording electrode. However, a method has been proposed in which the counter electrode is moved while maintaining the size of the gap, and the recording sheet is moved along with this movement to record an image signal on the surface of the recording sheet. FIG. 1 shows an example of a device for carrying out such a recording method.The following describes the outline of the above-mentioned recording method based on this example of the device, and also describes its problems. .

In the figure, the recording electrode indicated by reference numeral 1 has a plate shape that is elongated in the direction perpendicular to the drawing, and a large number of needle electrodes are embedded in one end surface of the narrow width along the longitudinal direction.

The end points of these needle electrodes are aligned in one direction at minute intervals on the one end surface, so that voltage can be applied to any combination of needle electrodes depending on the image signal to be recorded. . Other recording electrodes that can be used include pin tubes and letter shapes.

In this example, the counter electrode 2 is formed into a drum shape, with its axial direction parallel to the length direction of the recording electrode 1, and its periphery being spaced apart from the above one end surface by a predetermined gap. They are provided so as to face each other in the length direction.

The counter electrode 2 is rotatable in the direction of the arrow, holds the toner T on its peripheral surface, and rotates in the direction of the arrow during recording.

The recording sheet S is non-conductive, and during recording, it is conveyed in the direction of the arrow by a conveyance system (not shown), and when its leading end intervenes in the gap between the recording electrode and the counter electrode, recording becomes possible.

The above-mentioned narrow part is called a recording part. As the recording sheet, ordinary plain paper, insulating resin film, etc. are used.

The powder toner T has conductivity and magnetism, and is held on the surface of the counter electrode 2 by the magnetic force of a magnet installed in the counter electrode 2.

In the recordable state, the back surface of the recording sheet S is in contact with the end surface of the recording electrode 1 in which the needle electrode is embedded, and its surface is in light contact with the layer of toner T on the counter electrode 2.

The counter electrode 2 rotates in the direction of the arrow at a circumferential speed corresponding to the moving speed of the recording sheet S, and in this state, an image signal is applied to the recording electrode 1. Then, in the recording section, a strong electric field is generated locally in the thickness direction of the recording sheet S according to the signal voltage, and due to the action of this electric field, the toner T on the counter electrode 2 is charged by electrostatic induction. The toner T is injected, and due to the interaction between this charge and the electric field, the toner T is selectively transferred to the surface of the recording sheet S according to the image signal. In this way, the toner image formed on the surface of the recording sheet S in accordance with the image signal is transferred to the recording sheet S by any method.
fixed on top.

When a pin tube is used as the recording electrode, an electric charge is applied to the back surface of the recording medium 2 according to the image signal, and the toner T is electrically connected to the applied electric charge by electrostatic transfer and the above-mentioned electric charge. The interaction causes it to adhere to the recording sheet.

In this way, recording by charging the recording medium is
Note: This is also possible when using the green electrode 1 mentioned above. However, such a recording method has the following problems.

First, during recording, the surface of the recording sheet and the toner layer on the counter electrode come into contact with each other, but the degree of contact changes, affecting recording, making the image density of the recorded image non-uniform, and increasing the resolution. Images are difficult to obtain.

Further, due to physical contact between the surface of the recording medium and the toner layer, significant background staining occurs on the recorded image. This background stain can be removed to some extent by changing the conveying speed of the recording medium and the moving speed of the toner to create sliding friction between the two. It becomes difficult to obtain a density image as a recorded image.

In addition, since magnetic toner is used, there is a magnetic pole of a magnet for toner retention near the recording section, and after a pulsed image signal is applied, it already adheres to the surface of the recording medium and participates in image formation. A portion of the toner that is being used is drawn back onto the opposing electrode by the action of the magnetic field.

In order to prevent this, it is necessary to lengthen the application duration of the pulsed image signal in accordance with the width of the recording area, and as a result, increasing the recording speed is limited. In order to solve these problems, the present inventor previously proposed a non-impact recording method using an apparatus as shown in FIGS. 2 and 3.

In order to reduce complexity, it should be noted here that the same reference numerals are used throughout all the drawings starting with FIG. 1 for parts that are unlikely to be confused. In FIG. 2, the reference numeral 20 indicates a counter electrode, the reference numeral 3 a magnet, the reference numeral 5 a toner tank, and the reference numeral 60 a toner supply roller.

A hollow cylinder 202 made of a conductive and ferromagnetic material, such as nickel, cobalt, or an alloy thereof, is fixed to the circumferential surface of the support sleeve 201 of the two opposing electrodes.

In other words, the peripheral surface of the counter electrode 20 is made of a material that has conductivity and ferromagnetism. The circumferential surface of the hollow cylinder 202 has minute non-conductive and non-magnetic convex portions 203-1, 203-2. ......,203-
i, . . . are provided so as to protrude at substantially the same height with a substantially constant areal density.

The circumferential surface of the hollow cylinder 202 with respect to the convex portion 203-i is referred to as a bottom surface portion. The height of the convex portions 203-i and the spacing between the convex portions are from several tens of Buddha's skins to several ribs.

The material of the convex portion 203-i includes synthetic resin, synthetic rubber,
Possible materials include glass and ceramics. Now, in this example,
The bottom surface further has a microscopic unevenness distribution.

The depth and pitch of the unevenness in this unevenness distribution are approximately the same as the particle size of the toner used, and are determined within a range of about 0.5 to 300 peaks depending on the average particle size of the toner. Below the counter electrode 20, there is a toner supply low hood 60.
is provided, and toner T is stored in a toner tank 5 provided below this toner supply roller 60. The toner T is provided with conductivity and magnetism and is a powder. Here, when the toner T is conductive, it means that the toner has a volume resistivity of 107 Q or less, preferably 1 pi or less in an electric field of 200 V/. The toner supply roller 60 is a non-magnetic sleeve containing magnets 6a, 6b, 6c, and 6d, and the toner T is
The magnets 6a, 6b, 6c, and 6d hold the toner on the sleeve, and the rotation of the sleeve transports the toner to the toner supply section.

On the other hand, a toner supply roller 60 is provided inside the counter electrode 20.
A toner supply V supply magnet 3 is fixedly installed in the stereotaxic layer in the device space so as to face the toner supply magnet 3 .

Like the magnets 6a, 6b, 6c, and 6d, the toner supply magnet 3 has an elongated shape in the direction perpendicular to the drawing, is magnetized in the direction perpendicular to its length, and has one pole attached to the toner supply roller 6. I'm facing the river. The toner T conveyed from the toner supply roller 6 to the toner supply section is drawn to the circumferential surface of the counter electrode 20 by the magnetic force of the toner supply magnet 3, adheres thereto, and covers the circumferential surface. And counter electrode 2
0 is rotated in the direction of the arrow, it is held on the circumferential surface and conveyed toward the recording section. Since the bottom sleeve 202 is made of a ferromagnetic material, it is easily magnetized by the magnetic field of the magnets 3 and 6a as it passes through the toner supply section, and after leaving the area of influence of the magnets, the supplied toner T is held by the magnetic force of residual magnetization. However, the counter electrode 20
The magnetic force that restrains the toner T covering the circumferential surface of the toner T on the circumferential surface portion is strong on the circumferential surface of the bottom sleeve, which is a ferromagnetic material, that is, on the bottom surface portion, and is weak on the convex portion 203i, which is a non-magnetic material. Therefore, by blade means not shown,
Once the toner T adhering to the convex portion 203-i is scraped off between the toner supply section and the recording section, only the toner held on the bottom surface of the counter electrode 20 will be conveyed to the recording section. The upper part of the layer of toner T is the convex part 203-i.
Do not exceed the top of the

The size of the mesh gap between the recording electrode 1 and the counter electrode 20 is set to about 30mm to 3000mm depending on the thickness of the recording medium S. However, needless to say, the size of the slit here is the distance between the end surface of the recording electrode 1 and the top of the convex portion 203-i located closest thereto. At this time, in the recording state, the end surface of the recording electrode 1 contacts the back surface of the recording medium S,
Convex portions 203-i are formed on the surface of the recording body S.

However, as described above, since the upper part of the toner T layer held on the bottom surface of the recording electrode 20 does not exceed the top of the convex part 203-i, there is no space between the toner T and the recording medium S. A constant micro gap is always maintained. Therefore, physical contact between the recording medium S and the toner T is effectively prevented, and the inconvenience caused by the physical contact is avoided. In addition, since the toner supply magnet 3 is placed at a position away from the recording section and there is no magnetic pole of a magnet with strong magnetic force near the recording section, there is no need to apply the pulse of the image signal for a long time, and the speed is high. Recording becomes possible. Instead of using the above-mentioned plating means, as shown in FIG. 3, a magnetic roller 70 may be used to suction and remove the excess toner on the counter electrode 20.

In the drawing, reference numeral 8 indicates a blade for removing toner adsorbed to the surface of the magnetic roller 70 from the surface. When recording using the recording method shown in FIGS. 2 and 3, it is true that images with high image density and high resolution can be obtained, and background stains can be effectively prevented.
When recording is performed continuously, the recording time becomes longer, and background stains and image disturbances appear.

An object of the present invention is to further improve the non-impact recording device in order to solve such problems.

The present invention will be described below with reference to illustrated embodiments.

FIG. 4 shows one embodiment of the invention.

A feature of the present invention is that, in this example, a toner transport path from the recording section to the toner supply section is provided with
This is due to the presence of the static eliminating charger 90 as a static eliminating means.
That is, the inventor of the present invention repeatedly conducted experiments to investigate the cause of the background staining and image disturbance, and as a result, found that this was caused by charging of minute convex portions on the counter electrode.

That is, since the minute convex portions 203-i are non-conductive, when they come into contact with the recording sheet S or the toner T, they are frictionally charged and electrically adsorb the powder toner T. .

If the toner that has adhered to the convex portions 203-i in this way adheres to the recording sheet S during recording, background stains will occur, and the charged convex portions 203-i will remove the toner that has transferred to the recording sheet S during recording. If it is adsorbed, image disturbance will occur. The static elimination charger 90 eliminates static electricity from the minute protrusions 203-i after passing through the recording section. This prevents toner from adhering to the convex portion 203-i, and makes it easier to remove the toner adhering to the convex portion 203-i. The toner that is easily removed is removed from the convex portion 203-i by interaction with the magnetic brush formed in the toner supply section or by the suction force of the magnetic roller 70. In this way, in the recording apparatus according to the present invention, the occurrence of background stains and image disturbances can be effectively prevented. It is desirable that the static elimination charger 90 is an AC charger.

The static eliminating means may also be disposed between the toner supply section and the magnetic roller 70 in FIG.

Of course, if only the charge is removed from the convex portion 203-i,
Since the toner adhering to the convex portion is not removed, after static electricity is removed, the toner adhering to the convex portion 203-i is forcibly removed from the convex portion before the toner reaches the recording section again. Although a means for removing is required, since the magnetic brush and the energy filter serve as the means, there is no need to provide a dedicated device for the means. If a dedicated device for the above means is provided as necessary, the device may include an air nozzle, a fur brush, a blade plate, etc. In Figures 5 to 8,
Here are four examples of the structure with the above-mentioned fine irregularities.

In these figures, (1) shows a side view, and (0) shows a plan view. In the example shown in FIG. 5, the concavo-convex structure has a structure in which minute non-conductive and non-magnetic convex portions 7 are formed on a bottom member 6 that is conductive and ferromagnetic. In the example shown in FIG. 6, the protrusions 7 protrude from the support 8, and the bottom member 61 is provided between the protrusions 7 on the support 8. In the example shown in FIG.

In the example shown in FIG. 7, the relief plates 71 are provided in a lattice pattern on the support 8, and the bottom sections 62 are provided between the respective lattice portions of the convex portions 71. In the example shown in FIG.

In this way, the convex portion may be connected as a whole. In this case as well, since the lattice unit of the convex portions and the width of the convex portions forming the lattice are minute, the convex portions 71 are referred to as minute convex portions.
In the example shown in FIG. 8, the protrusion 72 has a two-dimensionally minute thread-like shape, and the bottom portion is constituted by a two-dimensionally very small thread-like member 63.

The thread-like member 63 preferably has about 2 to 30 threads. Note that the counter electrode may be formed into a belt shape. lastly,
An explanation will be added regarding the function performed by the magnetic roller 70. In the practice of the present invention, the magnetic roller 70 forcibly removes toner adhering to the discharged convex portion from the convex portion, as described above. In addition to this role, this magnetic LoFu 70 also plays a role in removing records.
It performs the following functions. That is, the toner T covering the surface of the counter electrode 20 is transported as the counter electrode 20 rotates and does not approach the vicinity of the magnetic roller 70 and the counter electrode 20. Electrode 2
In addition to the magnetic force that restrains the toner T, a magnetic force that separates the toner T from the counter electrode 20 is exerted by the magnetic roller 70.

As mentioned above, since the toner T is only loosely restrained by the convex portion 203i on the circumferential surface of the counter electrode 20, the toner T adhering to the convex portion is completely absorbed by the magnetic roller. 701 is sucked in and captured.

Further, a portion of the toner T that is restrained at the bottom of the circumferential surface is also captured by the magnetic loaf 70. magnetic roller 70
In this way, the magnetic force of the toner T covering the surface of the counter electrode 20 is adjusted to such a magnitude that only an appropriate amount of the toner T is left on the bottom surface, and the rest is sucked and removed from the surface of the counter electrode 20. be.

At this time, the toner T left on the bottom part of the circumferential surface of the counter electrode
When passing through the vicinity of the magnetic roller 70, the toner particles are not aligned in the normal direction of the bottom surface, following the lines of magnetic force of the magnetic field of the magnetic roller 70, as shown in FIG. You will be kicked.

An appropriate amount of toner means that the tip of the toner arranged in this manner does not exceed the top of the convex portion 2031i. The toner T from which the surplus has been removed by the magnetic roller 70' is conveyed to the recording section as the counter electrode 20 rotates, but at this time, the alignment of the toner T is preserved. Then, when an image signal is applied to the recording electrode 1 and an electric field is locally generated, the toner T
Since the toner T is arranged in an array, the lines of electric force are concentrated at the leading end of the arrangement, that is, the toner closest to the recording medium S, and charge injection into this toner is promoted.
It adheres to the recording medium S very easily.

Note that the voltage applied as an image signal is 20 to 3000
V range, preferably 20 to 1500V,
The application method may be either direct current or optical current.

Methods for forming minute irregularities on the counter electrode by the bottom surface portion and the convex portions include a method using mechanical processing, a method using chemical corrosion processing, and a method using electrical surface treatment processing.

[Brief explanation of the drawing]

FIG. 1 is a side view showing only the essential parts of an example of a conventionally known non-impact recording device, and FIGS. 2 and 3 are side views showing an example of a non-impact recording device to be improved according to the present invention. Figure 4 is a side view showing only the essential parts of an embodiment of the present invention, Figures 5 to 8 are diagrams showing examples of the uneven structure on the surface of the counter electrode, and Figure 9 explains the function of the magnetic roller. This is a diagram for 1... Recording electrode, 20... Counter electrode,
202... Bottom sleeve, 203-1, 20
3-2,... ..., 203-i, ... minute convex portion, T...・Conductive magnetic powder toner, S
... Recording body, 90 ... Static elimination charger as a static elimination means. Rare A figure Rare 2 figure Sei 5 figure Rare 4 figure Rare 5 figure Camellia 6 figure Rare W figure Rare 8 figure Composition 9 figure

Claims (1)

[Claims] 1. A recording electrode and a counter electrode are placed facing each other with a predetermined gap in between, a recording sheet is interposed in the gap, powder toner is held on the surface of the counter electrode, and the recording electrode is Recording in which, while applying an image signal, the surface of the counter electrode is moved while maintaining the size of the gap, and at the same time the recording sheet is moved to form a toner image corresponding to the image signal on the surface of the recording sheet. In this method, it is formed into a drum or belt shape, the peripheral surface is made of a material that is conductive and ferromagnetic, and small non-magnetic and non-conductive convex portions are placed approximately uniformly on the peripheral surface. a counter electrode protruding at substantially the same height with areal density; a means for supplying and retaining conductive magnetic powder toner on the circumferential surface of the counter electrode; and the minute protrusion after passing through the recording section. and a means for forcibly removing the magnetic powder toner adhering to the minute convex portion from the convex portion before the magnetic powder toner adheres to the minute convex portion after the static neutralization reaches the recording portion. A non-impact recording device characterized by having.