JP2008114429A - Ion flow recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion flow recording head of a heating discharge type which can write a clear image by a low application voltage to a heating element. <P>SOLUTION: In the ion flow recording head 1 of the heating discharge type, a lateral width L<SB>2</SB>along a parallel arrangement direction of discharge electrodes 5a is made 10-40% of a pitch width L<SB>1</SB>of the discharge electrode 5a. A dot diameter becomes small. Moreover, electric flux density becomes high, and therefore an ion generation amount per unit area is increased, whereby a discharge amount becomes less varied. Printing omission is thus suppressed, enabling writing of the clear image. Also the application voltage can be lowered because the heating element attains small heat capacity. An improvement in the durability of the ion flow recording head 1 and saving of power are enabled accordingly. <P>COPYRIGHT: (C)2008,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.

  Whether or not the discharge electrode is heated in a state where a predetermined discharge control voltage is applied to the discharge electrode (the voltage in the voltage range where the discharge is generated by heating the discharge electrode but does not occur) There is known a heat discharge type ion flow recording head that controls the generation of ions by controlling (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 low-voltage-resistant driver IC such as 5 V drive used for heating control of the discharge electrode by a heating element is used to control the ion. 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 shows a driving method of 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 the discharge electrode is selectively heated by a heating means equipped with a heating element, whereby a discharge is generated between the discharge electrode arranged opposite to the counter electrode, and the electric field is further discharged. Electrons and ions emitted from the electrode are moved to the recording surface (front surface) of the storage medium to form an image by applying an electric charge. A drive signal voltage lower than the discharge control voltage is applied to the discharge electrode. The timing for applying and the timing for selectively heating the discharge electrode by the heating means based on the image information are synchronized.

In such an heat discharge type ion flow recording head, as shown in FIG. 5 (b), arranged a plurality of discharge electrodes 5a on the surface side of the insulating layer 13b is in parallel with a predetermined pitch L ₁ It has been, for obtaining a printing accuracy of the sharp image, the study of proper ratio of the horizontal width L ₂ along the parallel direction of the discharge electrode 5a to the pitch width L ₁ have been made.
JP 2003-326756 A WO2005 / 056297

In the study of the proper ratio of the horizontal width L ₂ of the discharge electrodes 5a to the pitch width L ₁ described above, studies initially discharge amount per unit area of the discharge electrode 5a, i.e. the ion generation amount is likely to be the same since it was believed to be better to as much as possible to the wide increases the amount of generated ions, for example, in the case where the discharge electrode 5a pitch L ₁ of which constitutes one pixel (one dot) was 125 [mu] m (resolution 200 dpi), the FIG 5 (b) as shown in, the lateral width _{L 2} and 85μm of each discharge electrode, had set the ratio of the width _{L 2} of the discharge electrodes 5a to the pitch width _{L 1} to 68%. However, in this way the width L ₂ of the discharge electrode 5a is set to 68% of the pitch width L _1, and writes the image by applying a voltage of 24V to the heating element for heating the discharge electrode 5a, FIG. 7 ( As shown in b), many printing omissions were observed due to variations in the discharge amount. In order to prevent the occurrence of this print omission, it is necessary to apply a high voltage of about 30V. Here, when a high voltage is applied to the heating element, there are problems that the service life of the ion flow recording head is shortened and the power consumption is increased. Moreover, when the width L ₂ of the discharge electrode 5a is subjected to writing tests by creating of the same 125μm pitch width L _1, you can not write the not apply a fairly high voltage to the heating element, and the dot diameter The image became large and a clear image could not be obtained. Therefore, better to narrow the width L ₂ of the discharge electrodes 5a to the pitch width L ₁ is, the dot diameter is reduced, also, the heat capacity is small, the finding that the voltage applied to the heating element may also be a low voltage Obtained. Further, according to subsequent studies, the amount of ion generation per unit area of the discharge electrode 5a is not the same, and if the area of the discharge electrode 5a is reduced, the electric flux density increases and the amount of ion generation per unit area increases. Obtained knowledge.

  The present invention has been made based on such research results, and an object of the present invention is to provide a heat-discharge type ion flow recording head capable of writing a clear image with a low applied voltage to a heating element. is there.

  The present invention comprises a plurality of discharge electrodes arranged in parallel at a predetermined pitch width on the front surface side of the insulating layer, and a heating element arranged on the back surface side of the insulating layer, each discharge electrode, Applying a voltage that generates a discharge by heating the discharge electrode without generating a discharge just by applying it, the presence or absence of ions generated by the discharge of each discharge electrode, the presence or absence of each discharge by the heating element In the heat discharge type ion flow recording head controlled by selective heating of the electrodes, the lateral width along the parallel direction of the discharge electrodes is 10 to 40% of the pitch width of the discharge electrodes. It is a recording head.

  Here, if the width of each discharge electrode is less than 10% of the pitch width, the dot diameter becomes too small compared to the pitch width and a clear image cannot be obtained. If the pitch exceeds 40% of the pitch width, the dot diameter becomes large as in the conventional case, a clear image cannot be obtained, and high voltage needs to be applied to the heating element, which is not preferable. In addition, when the ratio of the horizontal width of the discharge electrode to the pitch width is set to 10 to 40% as described above, for example, the pitch width of the discharge electrode constituting one pixel (1 dot) is 125 μm (resolution 200 dpi). The width of each discharge electrode is 12.5 to 50 μm.

  In the present invention, as described above, since the lateral width along the parallel direction of the discharge electrodes is 10 to 40% of the pitch width of the discharge electrodes, the dot diameter is reduced and the electric flux density is increased, resulting in a unit area. The amount of generated ions per hit increases and the variation in the amount of discharge decreases, so that the occurrence of missing prints is suppressed and a clear image can be written. In addition, since the heat capacity of the heat generating element is reduced, the applied voltage can be lowered, thereby improving the durability of the ion flow recording head and saving power.

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 plurality of discharge electrodes 5a constituting the discharge body 5 are arranged in parallel at a predetermined pitch width on the surface of the bent portion. ing.

  As shown in FIG. 1B, the discharge body 5 is connected to a plurality of narrow strip-like discharge electrodes 5a arranged in parallel along the lateral width direction of the projecting end 3, and to both ends of each discharge electrode 5a. It is composed of wide strip-like common electrodes 5b and 5b (see FIG. 2). As will be described later, each discharge electrode 5a is irradiated with ions under a predetermined condition. The discharge electrode 5a is a main part of the present invention and will be described in detail later.

  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 electrode 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 electrode 5b (discharge body 5) and applies a high voltage discharge control voltage to the discharge electrode 5a.

  On the other hand, a driver IC 6 is mounted in the IC cover 9 on the head substrate 4. The driver IC 6 controls heat generation of a heat generating element 13a described later, and the driver IC 6 and the head substrate 4 constitute a discharge control device 7.

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

  Further, as shown in FIGS. 2 and 3A, a comb-like heating electrode 11 and a strip-like individual heating electrode 12 are formed on the upper surface of the flexible substrate 10. More specifically, as shown in FIG. 2, the heating electrode 11 includes a narrow comb-shaped heating comb electrode 11a and a U-shape connected to each base end of the heating comb electrode 11a. And a wide heating common electrode 11b. Between the heat generating comb electrodes 11a, the heat generating individual electrodes 12 are arranged in parallel with the heat generating comb electrodes 11a. That is, on the flexible substrate 10, the comb electrodes 11a for heat generation and the individual electrodes 12 for heat generation are alternately arranged. The heat generating comb-teeth electrode 11a, the heat generating common electrode 11b, and the heat generating individual electrode 12 can be formed by etching after printing a conductor such as gold paste on the surface of the flexible substrate 10 formed in a flat shape. .

On the heat generating comb electrode 11 a and the heat generating individual electrode 12, the heating means 13 of the discharge control device 7 is disposed. The heating means 13 is constituted by a belt-like heating element 13 a electrically connected to the heating comb electrode 11 a and the heating individual electrode 12. The heating element 13a can be formed by printing TaSiO ₂ , RuO ₂ or the like on the top of the heating comb electrode 11a and the heating individual electrode 12.

  Further, an insulating layer 13 b is covered on the flexible substrate 10 except for the ends of the heat generating common electrode 11 b and the heat generating individual electrode 12. The insulating layer 13b can be formed by printing a thin film resin such as polyimide, aramid, or polyetherimide having heat resistance and insulation.

  In addition, the discharge body 5 is disposed on the insulating layer 13b. Therefore, the discharge body 5 is insulated from the heating means 13 by the insulating layer 13b. Here, as shown in FIG. 3B, the discharge electrode 5a of the discharge body 5 is disposed at a position that coincides with the individual heating electrode 12 in the vertical direction, and the heat of the heating element 13a is efficiently discharged. 5a is transmitted. The discharge electrode 5a and the common electrodes 5b and 5b 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 13a generates heat when the driver IC 6 transmits a strobe signal to apply a strobe voltage to the heating comb electrode 11a and the heating individual electrode 12. That is, the strobe voltage between the heat generating comb electrodes 11a and the heat generating comb electrodes 11a and 11a on one side 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 13a corresponding to each discharge electrode 5a to generate heat, thereby heating any discharge electrode 5a. The heating means is not limited to such a method, and any means can be used as long as it can selectively heat the discharge electrode 5a. 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 16 is formed in a band shape on the surface of the common electrode 5b. The conductive material layer 16 is formed of silver paste or silver plating having excellent conductivity. With this configuration, the resistance value of the common electrode 5b can be reduced, and the potential difference generated between the discharge electrodes 5a can be reliably reduced.

Next, the operation 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 writing and erasing an image by the action of electric charge, and recording. 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 does not occur when only applied to the discharge body 5, but discharge occurs when 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 the heat generating element 13a via the arbitrary heat generating comb-tooth electrode 11a and the individual heat generating electrode 12, and the heat generating element 13a is heated to selectively discharge the discharge electrode 5a to a predetermined temperature (200 to 300). C.), a discharge is generated between the discharge electrode 5a and the counter electrode 21. Then, ions generated by the discharge of each discharge electrode 5a are moved to the recording surface (front surface) of the recording medium 20 by the electric field formed between the discharge body 5 and the counter electrode 21, and an image is recorded on the recording medium 20. A predetermined pattern of charge based on the data is applied. As a result, an electrostatic latent image having a predetermined pattern is formed on the recording surface (front surface) of the recording medium 20, and image writing is performed. The detailed control contents related to the image writing 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, on the insulating layer 13b (see FIG. 3), the plurality of discharge electrodes 5a constituting the discharge body 5 are arranged in parallel at a predetermined pitch width. (a), the lateral width _{L 2} along the parallel direction of each such discharge electrodes 5a, 10 to 40% of the pitch width _{L 1} of the discharge electrode 5a, more preferably those that form with 28 to 36% .

Here, the pitch width _{L 1} of the discharge electrodes 5a to constitute one pixel (1 dot) and 125 [mu] m (resolution 200 dpi), the prototype of ion flow recording head 1 a lateral width _{L 2} of the heating discharge type in which a 40μm of each discharge electrode A writing test was conducted. In this case, the ratio of the width _{L 2} of the discharge electrodes 5a to the pitch width _{L 1} becomes 34%. For comparison, as shown in FIG. 5 (b), the pitch width _{L 1} is 125 [mu] m (resolution 200 dpi), the width _{L 2} of each discharge electrode was also write tests using conventional is 85 .mu.m. In this conventional product ratio of the width L ₂ of the discharge electrodes 5a to the pitch width L ₁ is in the 68%.

In the writing test, the strobe voltage applied to the heating element 13a is changed in units of 2V from 20V to 28V to generate discharge in the discharge electrode 5a, and the surface potential charged on the surface of the recording medium 20 by writing at each applied voltage. Was measured. The test results are shown in FIG. Here, the higher the negative potential, the greater the discharge amount, that is, the amount of ion generation. As is clear from the test results, the discharge electrode 5a lateral width L ₂ of 40μm and 85μm and a high negative potential towards the discharge electrode 5a of width 40μm is compared to that of the width 85μm in any of applied voltage Moreover, the difference became more remarkable as the applied voltage was higher. In the case of the width of 85 μm, even if the applied voltage is increased from 20 V to 28 V, the surface potential increases only from 0 V to −18 V, whereas in the case of the width of 40 μm, from −7 V A significant increase in charge amount was observed up to -116V.

Further, FIG. 7, the discharge width _{L 2} of the electrode 5a is in those 40μm and 85 .mu.m, the heating element 13a by applying a strobe voltage of 24V, when the writing dot symbol y respectively conducted on the recording medium 20 Indicates the print status. There lateral width L ₂ of the discharge electrode 5a is that of 40μm, as shown in FIG. 7 (a), whereas the dot symbol y is clearly printed, the lateral width L ₂ of the discharge electrode 5a In the case of 85 μm, as shown in FIG. In FIG. 7, gray scale photographs of the recording medium 20 after writing are subjected to edge posterization using commercially available software [Adobe: Photoshop (registered trademark)], and then 50% as a reference. It is an image obtained by dividing into black and white and two gradations.

In the above writing test it has been described that setting the width _{L 2} of the discharge electrode 5a occupying the pitch _{L 1} to 34%, the width _{L 2} of the discharge electrode 5a occupying the pitch _{L 1} is 10-40% If it is preferably in the range of 28 to 36%, it can be assumed that substantially the same result as above is obtained. Here, the lateral width L ₂ of each discharge electrode 5a is less than 10% of the pitch L _1, it is not preferable because the dot size is not clear image can be obtained too smaller than the pitch width L _1, When the width L ₂ of each of the discharge electrodes 5a conversely exceeds 40% of the pitch width L _1, not clear image can be obtained by dot diameter similar to the conventional is increased, and the high voltage to the heating element 13a Since application is required, it is not preferable.

Thus, in the present invention, the width L ₂ along the parallel direction of each discharge electrode 5a, since 10 to 40% of the pitch width L ₁ of the discharge electrode 5a, the dot diameter becomes smaller, and electrostatic The bundle density is increased, the amount of ions generated per unit area is increased, and the variation in the discharge amount is reduced, so that the occurrence of print omission is suppressed and a clear image can be written. In addition, since the heat capacity of the heat generating element 13a is reduced, the applied voltage can be lowered, thereby improving the durability of the ion flow recording head 1 and saving power.

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. 3 is a schematic side view showing an image writing method by the ion flow recording head 1. FIG. (A) is a schematic diagram showing the relationship between the width L ₂ and the pitch L ₁ of this discharge electrodes 5a to the present invention, (b) is a schematic showing the relationship between the width L ₂ and the pitch L ₁ of the conventional discharge electrodes 5a FIG. It is a chart which shows the result of a writing test. It is explanatory drawing of a printing state.

Explanation of symbols

1 ion flow recording head 5a discharge electrode 13b width of pitch L ₂ discharge electrode insulating layer 13a heat generating element L ₁ discharge electrode

Claims (1)

A plurality of discharge electrodes arranged in parallel at a predetermined pitch width on the front surface side of the insulating layer, and a heating element arranged on the back surface side of the insulating layer, simply applied to each discharge electrode A voltage at which a discharge is generated by applying heat to the discharge electrode without applying a discharge is applied, and the presence or absence of ions generated by the discharge of each discharge electrode is selectively applied to each discharge electrode by the heating element. In a heat discharge type ion flow recording head controlled by heating,
The ion flow recording head characterized in that a horizontal width along the parallel direction of the discharge electrodes is 10 to 40% of a pitch width of the discharge electrodes.

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