JP2009119669A - Ion flow recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion flow recording head capable of making each of dots constructing a printing image small and uniform and capable of printing a sharp image with low energy applied to a heating means, by using a single discharge electrode and generating ions in areas around minute long holes. <P>SOLUTION: The ion flow recording head of a heat discharge type includes a discharge electrode 5a disposed on the surface side of an insulation layer 15, and a heating element 14 disposed on the rear side of the insulation layer 15. The presence or absence of discharge by the discharge electrode 5a, which is caused by the application of discharge control voltage to the discharge electrode 5a and the application of heat to the heating element 14, is controlled by the selective application of heat to each of the heat receiving portion 16 of the discharge electrode 5a by the heating element 14. Corners 18 are formed in each of the heat receiving portions 16 of the discharge electrode 5a and in the surface side of the discharge electrode 5a. Each ion-generating long hole 17 whose lateral width along a direction perpendicular to the direction of recording medium conveyance during printing is 10 to 80 μm is formed in a predetermined length in the direction of recording medium conveyance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ion flow recording head used as a rewritable paper for writing with an electrostatic latent image or a writing device for an electrostatic recording apparatus.

  Heating each heated portion of the discharge electrode with a predetermined discharge control voltage applied (a voltage in a voltage range where discharge does not occur when applied, but discharge occurs when the discharge electrode is heated) There is known a heat-discharge type ion flow recording head that controls the generation of ions by discharge by controlling the presence or absence of light (see, for example, Patent Document 1 and Patent Document 2). Such a heat-discharge type ion flow recording head does not require control of the voltage applied to the discharge electrode, and a driver IC corresponding to a low withstand voltage such as 5 V drive used for heating control of the discharge electrode by a heating element is used. Since the generation can be controlled, there is an advantage that the cost can be reduced and the size can be reduced.

In addition, International Application No. PCT / JP2006 / 304572 discloses a method for driving a heat discharge type ion flow recording head. This is to set a potential difference corresponding to the discharge control voltage between the discharge electrode of the ion flow recording head and the counter electrode formed on, or in contact with, or close to the back surface of the electrostatic latent image recording medium. Then, an electric field is formed, and each heated portion of the discharge electrode is selectively heated by a heating means equipped with a heating element, thereby generating a discharge between the discharge electrode and the counter electrode arranged to face each other. Further, by moving the ions generated by the discharge of the discharge electrode to the recording surface (surface) of the recording medium by an electric field, the charge constituting the electrostatic latent image is applied to form an image, The timing at which a drive signal voltage equal to or lower than the discharge control voltage is applied to the discharge electrode and the timing at which the discharge electrode is selectively heated by the heating means based on the image information are synchronized.
JP 2003-326756 A WO2005 / 056297

In such a heat discharge type ion flow recording head, as shown in FIG. 8A, a plurality of discharge electrodes a are arranged in parallel at a predetermined pitch width on the surface side of the insulating layer c, and A ladder-shaped discharge body d in which strip-shaped common electrodes b and b are coupled to both ends of the discharge electrode a is provided, and a discharge control voltage is applied to the discharge body d and is arranged on the back side of the insulating layer c. Ions are generated by selectively heating an arbitrary discharge electrode a by a heating means (not shown) provided with a heating element provided to generate a discharge. Moreover, such a In the plurality of discharge electrodes a discharge member d which are arranged in parallel at a predetermined pitch, the pitch L ₁ of each discharge electrode a constituting one pixel (one dot) 125 [mu] m (resolution 200 dpi) If the lateral width L ₂ of each discharge electrode a is set to 85 .mu.m.

By the way, it is known that discharge is likely to occur at a pointed portion of an electrode. Therefore, in the ladder-shaped discharge body d as described above, when discharging at each discharge electrode a, as shown in FIG. 8B, at the corners f and f on the surface side of the discharge electrode a. As a result of this discharge, particularly strong ionization occurs at the corners f and f of the discharge electrode a, and a large amount of ions are generated in the vicinity of the two corners f and f. That is, ions are individually generated in the vicinity of two corners f and f on both side edges that are separated from each other at intervals corresponding to the width of the discharge electrode a. Then, the mutually distant two positions of the corner portion f, by ions generated in the vicinity of f is moved to the recording surface of the recording medium by an electric field, if the width L ₂ of the discharge electrode a is 85 .mu.m, the recording Since the width of each dot h constituting the image printed on the surface is as large as 200 μm, there is a problem that the edge of the printed image cannot be displayed sharply.

  As described above, the reason why the widths of the individual dots h constituting the image printed on the recording surface are increased is that, in a plurality of discharge electrodes a arranged in parallel at a predetermined pitch width, each discharge electrode a As shown by the arrow e in FIG. 8B, the field lines of the electric field formed between the counter electrode disposed on the medium side spread in the lateral width direction from the corners f and f of the discharge electrode a. It is presumed that ions are formed along the lines of force and diffused.

  Further, the inventors of the present invention are provided with a single discharge electrode, that is, a so-called solid electrode, in which each discharge electrode a is continuously connected in place of the ladder-shaped discharge body d in which a plurality of discharge electrodes a are arranged in parallel. When an ion flow recording head was created and a printing experiment was performed, the shape of each dot constituting the printed image was substantially a perfect circle, but the individual dot diameter was as large as 250 to 300 μm. In addition, the inventors have found that discharge is not generated unless an applied energy of about 3 to 4 times that of the ladder-shaped discharge body d is applied, and excessive applied energy is required.

  The present invention has been made on the basis of such research results and uses a single discharge electrode. By generating ions in the area around the long hole, individual dots constituting a printed image are provided. It is an object of the present invention to provide a heat-discharge type ion flow recording head that can make the image small and uniform and can print a clear image with low energy applied to the heating means.

  The present invention comprises a discharge electrode disposed on the front surface side of an insulating layer and a heating element disposed on the back surface side of the insulating layer, and applying a discharge control voltage to the discharge electrode and heating by the heating element. In the heating discharge type ion flow recording head that controls the presence or absence of discharge of the discharge electrode caused by the above by selectively heating the heated portion of the discharge electrode by the heating element, each heated portion of the discharge electrode In addition, an ion generation slot having a corner on the surface side of the discharge electrode and having a lateral width of 10 to 80 μm along the direction orthogonal to the feeding direction of the recording medium during printing is along the feeding direction of the recording medium. The ion flow recording head is characterized by being formed with a predetermined length.

  Here, the ion generation long hole is formed as a through hole penetrating the front and back of the discharge electrode or as a non-through hole in which the surface of the discharge electrode is recessed, and thereby has a corner on the surface side of the discharge electrode. It can be. Further, if the width of the ion generation long hole is less than 10 μm, it is not preferable because individual dots constituting the image printed on the recording surface of the recording medium become too small to obtain a clear image. If the width of the generated long hole exceeds 80 μm, the dots become too large as in the conventional case, and a clear image cannot be obtained, which is not preferable.

  In the present invention, as described above, each heated portion of the discharge electrode is provided with a corner on the surface side of the discharge electrode and has a lateral width of 10 to 80 μm along the direction perpendicular to the recording medium feeding direction during printing. When the heated portion is heated, the corners of the hole edge surrounding the ion generation slot are formed by forming the ion generation slots in the predetermined length along the feeding direction of the recording medium. A discharge is generated at this point, and ions are generated in the area around the ion generation slot due to the ionization generated by this discharge. Since ions generated in the area around the ion generation slot move to the recording surface of the recording medium by the electric field, individual dots constituting an image printed on the recording surface of the recording medium are reduced, and Since the dots are uniform, the edge of the printed image becomes sharp, and a clear image can be printed. In addition, since the corner portion is likely to be discharged, the discharge can be performed even when the applied energy to the heating unit is small, and the applied energy can be reduced as compared with the case of discharging with a solid electrode.

First, the configuration of a heat discharge type ion flow recording head to which the present invention is applicable will be described.
As shown in FIGS. 1 (a) and 1 (b), the ion flow recording head 1 includes an aluminum heat radiating plate 2 formed with a substantially U-shaped projecting end 3 projecting downward, and the heat radiating plate 2. And a flexible head substrate 4 disposed so as to cover the protruding end 3. The head substrate 4 is bent in a substantially U shape and is attached to the protruding end 3, and a single discharge electrode 5 a constituting the discharge body 5 is disposed on the surface of the bent portion.

  As shown in FIG. 1B, the discharge body 5 is formed in a wide rectangular shape, and a portion located at the lower end of the protruding end 3 is a discharge electrode 5a, and both end portions of the discharge electrode 5a are Common electrodes 5b and 5b (see FIG. 2) are provided. As will be described later, ions are irradiated from a plurality of heated portions 16 (see FIG. 5) provided on the discharge electrode 5a under predetermined conditions.

  Further, an IC cover 9 is mounted above the head substrate 4, and a thin plate-like printed circuit board 8 is interposed between the IC cover 9 and the heat radiating plate 2. With this configuration, the printed circuit board 8 is protected by the IC cover 9. Further, a connector 8 a connected to an external control unit (not shown) is attached to the upper end portion of the printed circuit board 8 so as to be positioned immediately above the heat radiating plate 2.

  A high voltage substrate 9 a electrically connected to the common electrodes 5 b and 5 b of the discharge body 5 is disposed on the surface of the IC cover 9. The high-voltage substrate 9a transmits a drive signal to the common electrodes 5b and 5b (discharger 5) and applies a high discharge control voltage to the discharge electrode 5a.

  On the other hand, a driver IC 6 is mounted on the head substrate 4 in an IC cover 9. The driver IC 6 controls heat generation of a heat generating element 14 described later, and the driver IC 6 and the head substrate 4 constitute a discharge control device 7.

Next, the configuration of the head substrate 4 will be described with reference to FIGS.
The head substrate 4 includes a thin flexible substrate 10. The flexible substrate 10 is formed of a thin film resin such as polyimide, aramid, or polyetherimide having heat resistance and insulating properties.

  The upper surface of the flexible substrate 10 has a plurality of narrow-width heat generating comb electrodes 11a that are arranged in parallel at regular intervals and have a U-shape connected to the base ends of the heat generating comb electrodes 11a. An exothermic electrode 11 having a wide exothermic common electrode 11b is disposed, and further, between each exothermic comb electrode 11a, a thin strip-like individual exothermic electrode 12 is provided for each exothermic comb tooth. The electrodes 11a are arranged so as to be parallel and staggered. In addition, the pitch width between adjacent comb electrodes 11a for heat generation is a region constituting one pixel (one dot). The heat generating comb-tooth electrode 11a, the heat generating common electrode 11b, and the heat generating individual electrode 12 may be formed by etching after printing a conductor such as a gold paste on the surface of the flexible substrate 10 formed in a planar shape.

On the heat generating comb electrode 11 a and the heat generating individual electrode 12, a belt-like heat generating element 14 electrically connected to the heat generating comb electrode 11 a and the heat generating individual electrode 12 is disposed. The heating element 13 is constituted by the heating element 14, the heating comb electrode 11a and the heating individual electrode 12. The heat generating element 14 can be formed by printing TaSiO ₂ , RuO ₂ or the like on the heat generating comb-teeth electrode 11 a and the heat generating individual electrode 12.

  An insulating layer 15 is covered on the flexible substrate 10 except for the end portions of the heat generating common electrode 11 b and the heat generating individual electrode 12. The insulating layer 15 can be formed by printing a thin film resin such as polyimide, aramid, or polyetherimide having heat resistance and insulation.

  On the insulating layer 15, the discharge body 5 is disposed. Accordingly, the discharge body 5 is insulated from the heating means 13 by the insulating layer 15. As shown in FIGS. 2 and 3 (b), the discharge electrode 5a constituting the discharge body 5 has a position to be heated 16 corresponding to each individual heating electrode 12 in the vertical direction. A minute ion generation long hole 17 is formed in each heated portion 16. The ion generation long hole 17 is a main part of the present invention and will be described in detail later. The discharge electrode 5a and the common electrodes 5b and 5b having the ion generation long holes 17 can be formed by etching after forming a metal such as gold, silver, copper, or aluminum by vapor deposition, sputtering, printing, or plating. .

  The heating element 14 generates heat when the driver IC 6 transmits a strobe signal to apply a strobe voltage to the comb electrode 11a for heating and the individual electrode 12 for heating. That is, the strobe voltage between the heat generating comb electrodes 11a and 11a on both sides of the heat generating comb electrodes 11a and the heat generating individual electrodes 12 arranged alternately. Is applied to cause any portion of the heating element 14 corresponding to each heated portion 16 of the discharge electrode 5a to generate heat, thereby heating the arbitrary heated portion 16. This strobe voltage becomes energy applied to the heating means 13. Further, the heating means 13 is not limited to such a method, and any heating means 13 may be used as long as each of the heated parts 16 can be selectively heated. Further, the driver IC 6 is wire-bonded to a lead pattern extending from the heat generating common electrode 11b and the heat generating individual electrode 12 with a gold wire and then sealed with an IC protecting resin such as an epoxy resin.

  As shown in FIG. 2, a conductive material layer 18 is formed in a strip shape on the surfaces of the common electrodes 5b and 5b. The conductive material layer 18 is formed of silver paste or silver plating having excellent conductivity. With this configuration, the resistance values of the common electrodes 5b and 5b can be reduced, and the potential difference generated in the discharge electrode 5a can be made uniform.

Next, the operation mode of the ion flow recording head 1 will be described with reference to FIG.
FIG. 4 shows an ion flow recording head 1 arranged at a predetermined interval on the upper surface side of a recording medium 20 made of an electrostatic latent image type rewritable paper capable of repeatedly printing and erasing an image by the action of electric charge. A state is shown in which the counter electrode 21 is formed on, or in contact with, or close to the back surface of the medium 20.

In such a state, first, an electric field is formed by setting a potential difference corresponding to the discharge control voltage E ₀ between the discharge body 5 of the ion flow recording head 1 and the counter electrode 21. Here, the discharge control voltage refers to a voltage in a voltage range in which discharge is not generated only by being applied to the discharge body 5, but discharge is generated when the discharge body 5 is heated. This discharge control voltage is generated by superimposing a direct current voltage on an alternating current voltage. By applying a negative direct current voltage to the alternating current voltage and applying it to the discharge body 5, negative ions are generated when the discharge electrode 5a is heated. Can be made.

Next, the heating means 13 is controlled by the driver IC 6 in a state where the discharge control voltage E ₀ is applied. That is, a strobe voltage is applied to an arbitrary heating individual electrode 12 and the heating comb electrodes 11a and 11a on both sides thereof, and an arbitrary portion of the heating element 14 corresponding to each heated portion 16 of the discharge electrode 5a is heated. Then, by selectively heating the arbitrary heated portion 16 of the discharge electrode 5a to a predetermined temperature (200 to 300 ° C.), the discharge is performed between the arbitrary heated portion 16 of the discharge electrode 5a and the counter electrode 21. Is generated. Then, ions generated by ionization caused by this discharge are moved to the recording surface (surface) of the recording medium 20 by the electric field formed between the discharge body 5 and the counter electrode 21, and image data is transferred to the recording medium 20. A predetermined pattern of charge based on the above is applied. As a result, an electrostatic latent image of a predetermined pattern is formed on the recording surface (front surface) of the recording medium 20, and the image is printed. The detailed control contents related to the image printing by the ion flow recording head 1 are not the main part of the present invention, and the description thereof will be omitted.

Next, the main part of the present invention will be described.
As described above, minute ion generation long holes 17 are formed in each heated portion 16 of the single discharge electrode 5a constituting the discharge body 5 disposed on the insulating layer 15 (see FIG. 3). In the present invention, as shown in FIGS. 5 (a) and 5 (b), the ion generation slot 17 is provided with a corner 18 on the surface side of the discharge electrode 5a, and the recording medium 20 at the time of printing. The lateral width along the direction orthogonal to the feed direction is 10 to 80 μm, more preferably 30 to 60 μm, and the length along the feed direction of the recording medium 20 is set to a predetermined length 2 to 3 times the lateral width. is there. Here, as shown in FIG. 5A, each ion generation long hole 17 is formed as a rectangular long hole. Instead, semi-circular end portions are provided at both ends in the length direction. It may be a long hole provided. Each ion generation long hole 17 is formed as a through hole penetrating the front and back of the discharge electrode 5a as shown in FIG. 5 (b), whereby a corner 18 is provided on the surface side of the discharge electrode 5a. It has become. Each ion generation slot 17 can be formed as a non-through hole in which the surface of the discharge electrode 5a is recessed as shown in FIG. 5C. In this case as well, the surface of the discharge electrode 5a can be formed. The corner 18 is provided on the side.

In this configuration, as described above, an electric field is formed by setting a potential difference corresponding to the discharge control voltage E ₀ between the discharge body 5 of the ion flow recording head 1 and the counter electrode 21 (see FIG. 4). As shown in FIG. 6, by heating an arbitrary heated portion 16 by the heating means 13 in the state, the corner 18 of the hole edge surrounding the ion generation elongated hole 17 formed in the heated portion 16 is used. A discharge is generated, and ions are generated in an area around the ion generation slot 17 by ionization generated by the discharge. Then, the ions generated in the area around the ion generation slot 17 move to the recording surface of the recording medium 20 by the electric field, and an image is printed on the recording surface of the recording medium 20 with uniform small dots j.

  Here, the reason why the individual dots j constituting the image printed on the recording surface of the recording medium 20 are uniform and small is that the electric field formed between the discharge body 5 and the counter electrode 21 (see FIG. 4). As shown by the arrow g in FIG. 6, the force lines of the current are formed so as to deviate from the corner 18 of the hole edge surrounding the ion generation long hole 17 toward the center side of the ion generation long hole 17. It is presumed that by moving along the line, it is difficult to diffuse when the recording surface of the recording medium 20 is reached.

[Experimental example]
Four types of heating discharge type ion flow in which the pitch width of one pixel (1 dot) is 125 μm (resolution 200 dpi), and the ion generation elongated holes 17 having a lateral width of 10 μm, 40 μm, 60 μm, and 80 μm are respectively formed in the heated portion 16. The recording head 1 was prototyped and a printing experiment was conducted. For comparison, a printing experiment was also conducted using an ion flow recording head provided with a single discharge electrode, that is, a so-called solid electrode, in which the ion generation elongated hole 17 was not formed in the heated portion 16. In this printing experiment, in the case of the ion flow recording head 1 having the ion generation long holes 17, a strobe voltage of 24V is applied to the heating individual electrode 12 and the heating comb electrode 11a of the heating means 13, and the solid electrode is used. The provided image is printed by applying a strobe voltage of 26V, generating a discharge in a state where a discharge control voltage is applied to the discharge electrode 5a, and printing an image on the recording surface of the recording medium 20. The size of each dot constituting the image was measured. The result is shown in FIG. Here, when the ion generation elongated hole 17 has a width of 10 μm, the dot width of the printed image is 20 μm, when the width is 40 μm, the dot width is 80 μm, and when the width is 60 μm, the dot width is 119 μm. When the width was 80 μm, the dot width was 160 μm. In all cases, the size of each dot was uniform. On the other hand, in the solid electrode, the dot shape was a perfect circle, but the dot diameter was as large as 250 to 300 μm, and variation in size was observed between the dots. Further, in the conventional printing using the ladder-shaped discharge body d (see FIG. 8A) in which the discharge electrodes a having a lateral width of 85 μm are arranged in parallel, the dot width is 200 μm as described above, and therefore the ion generation slot 17 It can be seen that the dot width of the printed image is reduced in the ion flow recording head 1 having the above.

  Further, in the ion flow recording head provided with the solid electrode, the discharge does not occur unless the strobe voltage is applied to the heating means 13 three to four times, and excessive application energy is required for printing. In the ion flow recording head 1 provided with the ion generation long holes 17, it was recognized that the discharge was generated by applying the strobe voltage once. From this, it can be seen that the ion flow recording head 1 having the ion generation elongated holes 17 consumes less printing energy than the ion flow recording head having the solid electrode.

  FIG. 7B is a graph showing the relationship between the lateral width of the ion generation elongated hole 17 created based on the above experimental results and the size of the printed dots. As can be seen from this graph, the size of the printed dots is directly proportional to the lateral width of the ion generation slot 17.

  As can be seen from this graph, if the width of the ion generation elongated hole 17 is less than 10 μm, the individual dots constituting the image printed on the recording surface of the recording medium 20 become too small and a clear image is obtained. On the contrary, when the width of the ion generation elongated hole 17 exceeds 80 μm, the dot exceeds 160 μm, and gradually approaches 200 μm as printed by the ladder-shaped discharge body d (see FIG. 8A). As in the prior art, the dots are too large and a clear image cannot be obtained, which is not preferable.

  Thus, in the present invention, each heated portion 16 of the discharge electrode 5a is provided with the corner 18 on the surface side of the discharge electrode 5a, and the direction orthogonal to the feeding direction of the recording medium 20 during printing. Are formed in a predetermined length along the feeding direction of the recording medium 20, so that when the heated portion 16 is heated, ion generation occurs. A discharge is generated at the corner 18 of the hole edge surrounding the long hole 17, and ions are generated in the area around the ion generating long hole 17 by ionization generated by this discharge. Since ions generated in the area around the ion generation slot 17 move to the recording surface of the recording medium 20 by an electric field, individual dots constituting an image printed on the recording surface of the recording medium 20 are small. As a result, the edges of the printed image become sharp and a clear image can be printed. In addition, since the corner portion 18 is likely to be discharged, the discharge can be performed even when the applied voltage to the heating unit 13 is low, and the applied energy can be saved, as compared with the case of discharging with a solid electrode.

2A is a schematic side view of the ion flow recording head 1, and FIG. 2B is a schematic external perspective view of the ion flow recording head 1. FIG. 3 is a plan view of a head substrate 4. FIG. (A) is the sectional view on the AA line of FIG. 2, (b) is the sectional view on the BB line of FIG. 2 is a schematic side view showing an image printing method by an ion flow recording head 1. FIG. (A) is a partially enlarged plan view showing the ion generation long hole 17 formed in each heated portion 16 of the discharge electrode 5a, (b) is an enlarged cross-sectional view of the ion generation long hole 17 portion, and (c) is the others. It is an expanded sectional view of the ion generation long hole 17 part of the form. FIG. 6 is an explanatory diagram showing the movement direction of ions generated in an area around the ion generation long hole 17. (A) is a chart showing the results of a printing experiment, and (b) is a graph showing the relationship between the width of the ion generation slot 17 created based on the experimental results and the size of the printed dots. (A) is a plan view showing a conventional ladder-shaped discharge body d in which a plurality of discharge electrodes a are arranged in parallel at a predetermined pitch width, and (b) shows an ion generation state at corners f and f of the discharge electrode a. It is explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion flow recording head 5a Discharge electrode 14 Heating element 15 Insulating layer 16 Heated site | part 17 Ion generation long hole 18 Corner | angular part

Claims (1)

A discharge electrode disposed on a front surface side of the insulating layer; and a heating element disposed on a back surface side of the insulating layer, and the discharge electrode is generated by applying a discharge control voltage to the discharge electrode and heating by the heating element. In a heating discharge type ion flow recording head that controls the presence or absence of discharge of the discharge electrode by selective heating of each heated portion of the discharge electrode by the heating element,
In each heated portion of the discharge electrode, an ion generation elongated hole having a corner on the surface side of the discharge electrode and having a lateral width of 10 to 80 μm along the direction perpendicular to the feeding direction of the recording medium at the time of printing, An ion flow recording head, which is formed with a predetermined length along the feeding direction of the recording medium.

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