JPH02188273A - Image recording device - Google Patents

Abstract

PURPOSE:To enhance the insulating characteristics of an area between adjacent pin electrodes and prevent current leakage progressively by allowing pin electrodes which constitute and electrode array to be depressed from the surface of an electrode support of pin electrodes. CONSTITUTION:An electrode support 10 consists of two long plate materials 10a put together in a mutually opposed manner with a specified clearance provided in the axial direction of a sleeve 2, and is formed like a trapezoidal block in cross-section as a whole. Many pin electrodes 9 are implanted in line in the longitudinal direction of the electrode support 10 in a clearance between the sections of the electrode support 10. The pin electrodes 9 are implanted in such a manner that their tops are slightly depressed from the surface of the electrode support 10. The base end of each pin electrode 9 protruding from the lower end surface of the electrode support 10 is drawn out without being crossed and bounded together into an electric cord 11 which is connected to a recording power supply.

Description

[Detailed description of the invention] Uchikurijo ■Ushikobu! The present invention relates to an image recording apparatus that performs recording on a transfer material by conveying developer to an electrode array disposed on a sleeve and selectively applying a voltage corresponding to a recording signal to pin electrodes of the electrode array.

This type of image recording apparatus has been developed in response to demands for miniaturization of the entire apparatus and simplification of the apparatus configuration.

In order to improve image quality and recording efficiency in such an image recording device, it is necessary to suppress leakage as much as possible between each pin electrode of the electrode array to which high voltage is selectively applied. .

That is, if leakage can be suppressed as much as possible, the following effects will be achieved.

(2) Since a correspondingly higher voltage can be applied to the pin electrode, an image with higher density, that is, an image with higher clarity, can be obtained.

■As a high voltage can be applied to the pin electrode, the bias voltage to the back electrode facing the electrode array can be set to a correspondingly higher level. This means that it is possible to obtain a clear image with less noise (a phenomenon that deteriorates image quality due to a small potential difference between the peripheral area and the area to be printed).

(2) For reasons described later, by using toner with low electrical resistance as a developer and recording by injecting charge into the toner from a pin electrode, it is possible to improve recording efficiency as a result.

However, no conventional image recording apparatus has taken this point into consideration.

The present invention has been made in view of the current situation, and it is an object of the present invention to provide an image recording apparatus that can improve image quality and recording efficiency.

According to the present invention, a developing material is conveyed to an electrode array arranged in a convex shape on a sleeve, and a voltage corresponding to a recording signal is selectively applied to a pin electrode of the electrode array to record on a transfer material. The recording head is characterized in that the electrode array is supported by an electrode support material, and the tip surfaces of the pin electrodes are recessed with respect to the surface of the electrode support material.

In certain cases, by recessing the tips of the pin electrodes, the distance between adjacent pin electrodes, that is, the insulation, can be improved, which will reduce the creepage, which is a cause of leaks, as described below. This means that electrical discharge, etc. can be suppressed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front sectional view showing a schematic structure of an image recording device according to the present invention, FIG. 2 is a perspective view of an electrode array, FIG. 3 is a cross-sectional view thereof, FIG. 4 is a vertical sectional view, and FIG. is a bottom view.

First, the general configuration of this image recording apparatus will be explained.

A sleeve 2 is fixedly arranged at a predetermined position in the main body of the apparatus, and a magnet roller I is rotatably provided inside the sleeve 2. When the magnet roller 1 is rotated in the clockwise direction indicated by the arrow mark in the figure, the toner 17 charged with positive or negative polarity is taken out from the casing 16 as the magnetic roller 1 rotates. The removed toner 17 moves over the peripheral surface of the sleeve 2 in a thin film-like manner, and is clamped and supported in an opening 20 formed on the left end peripheral surface of the sleeve 2 with the leading end protruding. The head 3, more specifically, is transported to the position of the electrode array 4 embedded therein.

A back electrode holder 6 is located on the left side of the recording head 3.
The back electrodes 7 embedded in the pin electrodes 9 forming the electrode array 4 are arranged opposite to each other.
When a voltage corresponding to the recording signal is selectively applied to the electrode array 4 and a predetermined potential difference is created between the electrode array 4 and the back electrode 7, the signal is transported between the two while being guided by the tip of the back electrode 7. The recording head 3 repulses the charged toner 17 toward the transfer material (for example, recording paper) 5 by Coulomb force, thereby performing an image recording operation. The transfer material 5 on which the recording operation has been performed is then conveyed to a fixing device (not shown), where a fixing process is performed.

However, the voltage application to each pin electrode 9 of the electrode array 4 is performed by the recording power supply 12, and the bias voltage application to the back electrode 7 is performed by the bias power supply 8. Further, the reason why the recording head 3 is arranged in a convex shape from the circumferential surface of the sleeve 2 is to increase the distance between the electrode array 4 and the back electrode 7, thereby increasing the recording efficiency.

The toner 17 is charged by frictional charging at the installation position of a doctor blade 18 that is attached to the upper left wall of the casing 16 and regulates the height of the toner 17 conveyed on the circumferential surface of the sleeve 2 .

In addition, as for the developer, in the above embodiment, a one-component developer made of insulating magnetic toner was shown, but a one-component developer made of conductive toner may be used, or a two-component developer made of toner and a magnetic carrier may be used. You may also do so.

Here, when a one-component developer consisting of conductive magnetic toner is used as the developer, since the toner is conductive,
A toner chain is formed on the sleeve 2 by magnetic force without being charged. When voltage is applied to this toner chain from the pin electrode 9, charge is injected into the toner chain,
An electric field is formed between the back electrode 7 and the back electrode 7. When the electrostatic force of the formed electric field overcomes the magnetic force of sleeve 2,
The toner chain is cut, and the toner flies in the direction of the back electrode 7 and adheres to the transfer material 5. When such a developer is used, the recording efficiency is high because charges are injected into the tips of the toner chains, and the advantage is that the voltage applied to the electrode array 4 may be low (several volts to several tens of volts).

On the other hand, when a one-component developer made of insulating magnetic toner is used as the developer, the toner is charged by friction with a part of the developing device such as the sleeve 2. When the electrostatic force caused by the electric field between the electrode array 4 and the back electrode 7 overcomes the magnetic force of the sleeve 2, the charged toner flies out of the sleeve 2 and adheres to the transfer material 5.

When a two-component developer consisting of an insulating non-magnetic toner and a conductive magnetic carrier is used as the developer, the toner is frictionally charged with the carrier and is conveyed on the sleeve 2 while adhering to the circumferential surface of the carrier. When a voltage of the same polarity as that of the toner is applied to the electrode array 4, the toner is repelled by this, flies out of the sleeve 2, and adheres to the transfer material 5. When using such a developer, the carrier is conductive;
It has the advantage of good recording efficiency because charge is injected.

When a two-component developer consisting of an insulating non-magnetic toner and an insulating magnetic carrier is used as the developer, the toner is triboelectrically charged with the carrier and is conveyed on the sleeve 2 while being attached to the carrier circumferential surface by electrostatic force. Ru. When a voltage of the same polarity as that of the toner is applied to the electrode array 4, the toner repels this, flies from above the sleeve 2, and adheres to the transfer material 5. When such a developer is used, since the carrier is insulating, there is an advantage that leakage does not occur between the electrode array 4 and the back electrode 7 via the carrier.

Next, the specific structure of the recording head 3 will be explained with reference to FIGS. 2 to 5. This recording head 3 has a structure in which a large number of pin electrodes 9 made of enamelled wire are embedded in an electrode support material 10 made of acrylic resin. That is,
The electrode supporting material 10 is formed by facing two plate members 10a, 10a which are long in the axial direction of the sleeve 2 with a predetermined gap therebetween, and has a block shape having a trapezoidal cross section as a whole. The structure is such that a large number of pin electrodes 9 are arranged in the longitudinal direction of the electrode support material 10 in the gap between the electrode support materials IO. however,
As shown in the figure, the pin electrodes 9 and
The upper end surface (the tip end surface when assembled in the image recording apparatus as described above) is slightly depressed from the surface of the electrode support material 10.

This recording head 3 is manufactured as follows.

That is, the pin electrode 9... is inserted into the gap, and while this state is maintained, an insulating resin such as epoxy resin 10b is poured into the gap, and this is solidified. It has become. Thus, in the solidified state of the epoxy resin 10b, the pin electrodes 9... and the electrode support material 10
will be integrated.

Note that in this manufacturing state, the tip surfaces of the pin electrodes 9 are flush with the surface of the electrode support material 10, but by performing the following steps, the pin electrodes 9 will be depressed. Become. That is, the tip side of the recording head 3, in which the tip surfaces of the pin electrodes 9 and the surface of the electrode support material lO are flush with each other, is immersed in an aqueous solution of iron chloride (+hydrochloric acid), and the concentration, temperature, A depression is formed by osteolyzing (etching) the pin electrodes 9 to a predetermined length by controlling the immersion time and the like.

As shown in FIG. 5, the proximal ends of the pin electrodes 9 protruding from the lower end surface of the electrode supporting material 10 are pulled out without intersecting with each other, and are bundled at the pull-out section to form the recording It is an electrode cord 11 connected to a power source.

The manufacturing method of the recording head 3 and the materials of the electrode support material 10 and the pin electrodes 9 are not limited to those described above, and the pin electrodes 9 are individually insulated.
Any structure may be used as long as it is supported by the electrode support material 10 insulated from the electrode array 4.

However, if a magnetically permeable material such as nickel or ferrite coated with insulation is used for the pin electrodes 9..., the magnetic flux density on the surface of the pin electrodes 9 can be increased to a higher level, so the hotaka (chain-like Refers to the length of the conductive toner spike.
There is an advantage that the longer this value is, the faster and more reliable the recording operation can be set.

Next, according to FIGS. 6 to 10, in the present invention,
As described above, the tip surface of the pin electrode 9... is attached to the electrode support material 10.
The effect of caving in from the surface will be explained using experimental results using a comparative example.

However, FIG. 6 is a longitudinal sectional view showing the recording head of the present invention, and FIG.
The figure is a vertical cross-sectional view showing a comparative example having the same typical dimensions as the recording head of the present invention, Figure 8 is a diagram illustrating the dimensions of the main parts of both, and Figure 9 is a diagram showing toner on the surface of the recording head of the present invention. A model diagram showing the adhered state, FIG. 10, is also a model diagram of a comparative example.

The specifications of the recording head 3 of the present invention and the comparative example 30 used in this experiment are as follows.
Occurrence of leakage when every other pin electrode 9 (90) in (30) is connected to the power supply, the remaining pin electrodes 9 (90) are grounded, and the voltage applied from the power supply is gradually increased. We conducted an experiment to observe the

” ■Diameter a [μm] of pin electrode 9 (90) Inventive recording head: 200 Comparative example: 200 ■Distance between adjacent pin electrodes! [μm] Recording head of the present invention: 20 Comparative example = 20 ■ Surface of electrode support material 10 (100) and pin electrode 9 (90
) Distance (concave it) d (μm) Recording head of the present invention: 20 Comparative example: 0 In Comparative Example 30, leakage occurred when the power supply voltage was set to -300 to -400V. On the other hand, in the recording head 3 of the present invention, no leakage occurred even when the power supply voltage was set to -500V.

Discussion Based on the above experimental results, it is considered that leakage occurs due to creeping discharge that occurs without passing through the toner 17. That is, in the recording head 3 of the present invention, the pin electrodes 9...
By recessing, the distance l between the pin electrodes becomes essentially g+2d=60 μm, and! This is because the distance l between the pin electrodes is larger than that of Comparative Example 30, which is 20 μm, so it is thought that creeping discharge is less likely to occur due to improved insulation.

Next, as shown in FIGS. 9 and 10, experimental results will be described when a recording operation was actually performed using the toner 17. However, for convenience of explanation, the diameter of the toner (toner particles) 17 is the distance between the pin electrodes! It is drawn larger than that.

In this experiment as well, it was confirmed that the recording head 3 of the present invention was able to reduce the degree of leakage, as in the above experimental example.

Discussion Based on the above experimental results, it is believed that in addition to the above-mentioned creeping discharge, leakage can be suppressed for the following reasons.

That is, when the electrical resistance of the toner 17 is large, the pin electrode 9 a (
90a) and the adjacent pin electrode 9b (to which no voltage is applied)
90b), the amount of charge leaking through the toner 17 is small; It is thought that there is not much difference in the degree of leakage between the two, but when the electrical resistance of the toner 17 is small, the degree of leakage between the two is large (different).

This phenomenon can be explained by the following reasons. That is, the 10th
As shown in the figure, in the case of Comparative Example 30, both pin electrodes 9a and 9b are electrically connected by toner 17, and in order to cause leakage through this, one toner 17 is required.
However, in the case of the recording head 3 of the present invention, the substantial distance β between the pin electrodes is large due to the above-mentioned reason, so at least three toners 17 are required. Therefore, the degree of leakage can be reduced accordingly.

Further, based on this consideration, according to the present invention, as a developer,
Even when using conductive toner 17 with low electrical resistance, leakage is less likely to occur, so there is no problem when using conductive toner 17, which is convenient for improving recording efficiency. This has the advantage that the recording operation can be performed without any problems. Note that leakage due to conductive carriers can also be prevented for the same reason.

The illustrated embodiment has been described in its entirety as described above, but the present invention can be modified in various ways. That is, in the above embodiment, an image is recorded on a transfer material 5 such as a recording paper, but the image is first recorded on an intermediate transfer material such as a transfer belt, and then this recorded image is transferred to a paper such as plain paper. It is also possible to take the form of re-transferring the image.

In the case of the present invention described above, the pin electrodes constituting the electrode array are recessed from the surface of the electrode supporting material that supports them, so that the insulation between adjacent pin electrodes can be improved accordingly. This means that leaks can be suppressed as much as possible.

Therefore, for the reasons mentioned above, image quality and recording efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a schematic structure of an image recording device according to the present invention, FIG. 2 is a perspective view of an electrode array, FIG. 3 is a cross-sectional view thereof, FIG. 4 is a vertical sectional view, and FIG. is a bottom view, FIG. 6 is a vertical sectional view showing the recording head of the present invention, FIG. 7 is a vertical sectional view showing a comparative example having the same typical dimensions as the recording head of the present invention, and FIG. 8 is a longitudinal sectional view of the main parts of both. Drawing explaining dimensions, No. 9
The figure is a model diagram showing a state in which toner adheres to the surface of the recording head of the present invention, and FIG. 10 is a model diagram of a comparative example. 2... Sleeve, 3... Recording head, 4... Electrode array, 5... Transferred material, 7... Back electrode, 9...
・Pin electrode, 10... Electrode support material, 17... Toner patent applicant Minolta Camera Co., Ltd. Figure 1 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] (1) An image recording device that records on a transfer material by conveying developer to an electrode array arranged in a convex shape on a sleeve and selectively applying a voltage corresponding to a recording signal to the pin electrodes of the electrode array. An image recording apparatus characterized in that the electrode array is supported by an electrode support material, and the tip surfaces of the pin electrodes are recessed with respect to the surface of the electrode support material.