WO2007102219A1

WO2007102219A1 - Heating discharge print head drive method

Info

Publication number: WO2007102219A1
Application number: PCT/JP2006/304572
Authority: WO
Inventors: Hisanobu Matsuzoe
Original assignee: Fukuoka Technoken Kogyo, Co., Ltd.
Priority date: 2006-03-09
Filing date: 2006-03-09
Publication date: 2007-09-13
Also published as: JPWO2007102219A1; JP4146885B2

Abstract

A heating discharge print head drive method for efficiently causing electric discharge by controlling the timing at which a voltage is applied to a discharge electrode and the timing at which the discharge electrode is heated. The energy is excellently saved, the amount of ions produced is accurately controlled to simply perform gradation recording, and a high-quality image can be created. The method comprises a potential difference setting step of setting a potential difference corresponding to the discharge control voltage between a heating discharge print head having a discharge electrode and heating means for selectively heating the discharge electrode and an opposing electrode opposed to the discharge electrode in such a way that a recording medium writable/erasable by the action of electric charge is interposed between the print head and the opposing electrode so as to produce an electric field and a discharge electrode heating step of allowing the heating means to selectively heating the discharge electrode according to image information. At the head voltage applying step of the potential difference setting step, the timing at which a drive voltage is applied to the discharge electrode is synchronized with the timing of the discharge electrode heating step.

Description

Driving method of heating and discharging type print head

Technical field

The present invention relates to a method for driving a heat-discharge type print head for forming an image on an electrostatic development type recording medium capable of repetitive recording by the action of electric discharge.

Background art

In recent years, as shown in (Patent Document 1), an ion irradiation method, which is an electrostatic latent image forming method different from the electrophotographic method, has been developed.

The electrophotographic method uses two processes, uniform charging and exposure, to release the exposed portion of the charge on the uniformly charged photoconductor, thereby forming an electrostatic latent image on the photoconductor as the electrostatic latent image carrier. On the other hand, in the ion irradiation method, in an atmosphere where ions can be generated (such as in the air), selective charging by irradiation of ions generated by the discharge of electrons from the discharge electrode (electrostatic latent image formation charging) The electrostatic latent image can be completely formed on the electrostatic latent image carrier (there is no need to be a photoconductor as long as it is an insulator). It is a method.

Further, (Patent Document 2) discloses a specific shape of an ion irradiation type print head compatible with a horizontal printer and an image forming apparatus including the shape.

In particular, the heating and discharging methods shown in (Patent Document 1) and (Patent Document 2) are in a state in which a voltage (discharge control voltage) is generated in which a discharge is generated by heating without generating a discharge just by being applied to the discharge electrode. Thus, by controlling the presence or absence of heating of the discharge electrode, the generation of ions is controlled by controlling the presence or absence of discharge, and it is not necessary to control the voltage applied to the discharge electrode. As a result, it is possible to control the occurrence of discharge with a low withstand voltage driver IC such as 5V drive used to control heating by a heating resistor, etc., and this is the most excellent control method from the viewpoint of discharge control. It can be said that there is.

Incidentally, as a digital paper at the present time, a minute ball is color-coded into two colors (for example, black and white), and the ball is rotated by the difference in electrical characteristics of each color to display an arbitrary color, a minute ball Two colors (for example, black and white) of fine powder are mixed in the ball. An electrophoretic method in which only one color is floated and displayed due to the difference in electrical characteristics of the fine powder of color, and a liquid crystal that displays the background color of the part where the shutter is opened by opening and closing the liquid crystal shutter of the liquid crystal plate or small liquid crystal block There are methods.

Patent Document 1: Japanese Patent Laid-Open No. 2003-326756

Patent Document 2: WO2005Z056297

Disclosure of the invention

Problems to be solved by the invention

[0003] However, the above-mentioned conventional technology has had the following problems.

(1) The heating and discharging type print heads of (Patent Document 1) and (Patent Document 2) are easy to control the discharge, and are optimal for non-contact writing on an electrostatic development type recording medium. As for the control of the generation amount, it was not fully studied.

(2) If the amount of ions generated is different, the amount of ions irradiated per unit area of the recording medium will be different, resulting in a change in the image density. In order to achieve this, controlling the amount of ion irradiation has become an important issue.

(3) In particular, in order to perform gradation recording, it was necessary to control the irradiation amount of ions in detail, and it was necessary to suppress fluctuations in the amount of generated ions.

[0004] The present invention meets the above-mentioned demand. By controlling the timing of applying a voltage to the discharge electrode and the timing of heating the discharge electrode, the discharge can be efficiently generated, and the energy saving property is excellent. At the same time, the purpose is to provide a method for driving a heat-discharge-type printhead that can easily control gradation and accurately record the amount of ions generated, and that can form high-resolution and high-quality images. And

Means for solving the problem

[0005] In order to solve the above problems, a driving method for a heat-discharge type print head according to the present invention has the following configuration.

According to a first aspect of the present invention, there is provided a heating / discharging printhead driving method comprising: a heating / discharging printhead having a discharge electrode having an electron emission site; and a heating means for selectively heating the discharge electrode; The potential difference corresponding to the discharge control voltage between the recording electrode that can be written and erased by the action of the counter electrode and the counter electrode that is disposed opposite to the discharge electrode. A potential difference setting step for forming an electric field by setting the voltage and a discharge electrode heating step for selectively heating the discharge electrode by the heating means based on image information. In the head-side voltage application step, the timing of applying a driving voltage lower than the discharge control voltage to the discharge electrode and the timing of the discharge electrode heating step are synchronized.

This configuration has the following effects.

(1) In the potential difference setting step, a potential difference corresponding to the discharge control voltage is set between the discharge electrode and the counter electrode to form an electric field. Since the discharge can be generated only by selectively heating the discharge electrode, it is not necessary to control the high voltage and the generation of the discharge can be easily controlled.

(2) By synchronizing the timing of applying the driving voltage to the discharge electrode in the head side voltage application process and the timing of selectively heating the discharge electrode in the discharge electrode heating process, the discharge can be reliably performed. As a result, it is possible to reduce variations in the amount of ions generated, and it is excellent in image quality reliability and energy saving without applying unnecessary voltage to the discharge electrode.

Here, an electric field is set by setting a potential difference corresponding to the discharge control voltage between the discharge electrode of the heat discharge type print head and the counter electrode formed on, or in contact with, or close to the back side of the recording medium. And the discharge electrode is selectively heated by a heating means including a heating resistor, a laser irradiation part, etc., so that a discharge can be generated between the discharge electrode and the counter electrode arranged opposite to each other. In addition, electrons and ions whose discharge electrode force is also released by the electric field can be moved to the recording surface (surface) of the recording medium, and the image can be written or erased by the action of the charges. By selecting the heating location by this heating means, it is possible to easily discharge electrons by selectively emitting electrons from the vicinity of any heating position (electron emission site) of the discharge electrode.

It should be noted that the discharge control voltage means that a discharge does not occur between the discharge electrode of the heat-discharge type print head and the counter electrode on the recording medium only by the potential difference, but the discharge occurs by heating the discharge electrode. Says voltage range. Discharge here means that discharge electrode force electrons are emitted. The emitted electrons ionize oxygen and nitrogen in the atmosphere and To reach the recording surface of the recording medium.

[0007] For example, the discharge electrode is formed in a comb shape by connecting one end of a plurality of electron emission sites with a common electrode, or formed in a ladder shape or the like by connecting both ends of a plurality of electron emission sites with a common electrode In addition, it can be formed into a single flat plate shape such as a rectangular shape or a square shape (see, for example, JP-A-2003-326756, WO2005Z056297).

By providing a common electrode in the vicinity of the electron emission site, such as a comb-type or ladder-type, the cooling area of the discharge electrode and the responsiveness to heating stop are improved by increasing the heat radiation area of the discharge electrode and increasing the heat capacity. In addition, since a stable voltage can always be applied by reducing the resistance value, the stability of discharge can be further improved. Incidentally, in the discharge electrode formed in a flat plate shape, the vicinity of the heating position by the heating means is an electron emission site, and other than the electron emission site is a common electrode.

In particular, when the width of the common electrode is wider than the width of the electron emission site, the cooling effect of the discharge electrode, which is temporarily heated to 100 to 300 ° C, is improved, and heat can be prevented from being burned. In addition, the discharge can be stopped in response to the heating off quickly, the discharge time interval can be shortened and the presence / absence of the discharge can be switched in a short time, and the recording speed can be increased. In addition, the resistance value of the common electrode can be reduced, and the potential difference generated between the electron emission sites connected by the common electrode can be suppressed as much as possible. Therefore, the amount of electron emission at each electron emission site is reduced. Fluctuations and excellent discharge stability.

[0008] The discharge electrode is formed by depositing a metal such as gold, silver, copper, or aluminum on the substrate by vapor deposition, sputtering, printing, plating, or the like, and then etching as necessary to pattern the electron emission site or the common electrode. What is to be formed, and after thinning at least a part of a metal such as stainless steel, copper, aluminum, etc. by cutting or the like, patterning of the discharge electrode by etching or laser caching, etc., if necessary is suitable. Used for. In addition, the discharge electrode may be formed using a conductive material such as carbon.

When the discharge electrode is formed on the substrate, the material of the substrate may be any material as long as the discharge electrode can be formed on the surface and has heat resistance to withstand the heating by the heating means. Further, when heating is performed from the back side of the substrate by the heating means, those having a heat transfer property capable of transferring the heat generated by the heating means to the discharge electrode are preferably used. Specifically, A synthetic resin such as glass, polyimide, aramid, or polyetherimide is preferably used.

When the discharge electrodes are formed in a comb shape, the shape of each electron emission site can be formed in a substantially rectangular shape, a trapezoidal shape, a semicircular shape, a bullet shape, or a combination thereof. Further, the peripheral length around the edge of the electron emission site can be increased by further dividing a part of the electron emission site with a slit or the like, or by forming an uneven portion on the peripheral edge (for example, WO

2005Z056297). Since the discharge electrode emits a large amount of electrons from the periphery of the edge, it is possible to increase the amount of emitted electrons and the intensity of emitted light by increasing the amount of electron emission of the discharge electrode force by increasing the circumference around the edge. In addition, the discharge control voltage and heating temperature can be set low, and the energy saving and discharge generation efficiency are excellent. In addition, since the discharge control voltage can be set low, the discharge electrode has excellent long life.

Instead of dividing the end portion of the discharge electrode or forming the uneven portion on the peripheral edge portion, a discharge hole portion may be formed in the vicinity of the electron emission site (heating position). As a result, electrons can be emitted from the peripheral edge of the discharge hole, and the same effect as dividing the end of the discharge electrode can be obtained. The shape of the discharge hole portion can be formed in various shapes such as a substantially circular shape, a substantially elliptical shape, a polygonal shape such as a quadrangle and a hexagon, and a star shape. Further, the number and size of the discharge hole portions per one electron emission site (near the heating position) can be appropriately selected and combined. Note that the concave and convex portions and the discharge holes of the discharge electrode can be formed by the above-described etching or laser processing.

[0010] Further, a conductive material layer may be formed on at least the surface of the common electrode among the discharge electrodes.

As a result, the resistance value of the common electrode can be further reduced, the potential difference generated between each electron emission site can be reliably reduced, and the discharge stability is excellent. The conductive material layer only needs to have conductivity superior to that of the discharge electrode, and can be easily formed by silver paste screen printing or silver plating. By increasing the thickness of the conductive material layer, the resistance value of the common electrode can be reduced, and the discharge stability can be improved.

The thickness of the discharge electrode is preferably 0.1 μm to 100 m when it is formed with a force plate depending on the material. The discharge electrode tends to be affected by wear as the thickness of the discharge electrode becomes thinner than 0. m, and the life of the discharge electrode tends to be shortened. As the thickness exceeds 100 m, the heat capacity increases, and the response to heating on and off is increased. It tends to be lowered, and the deviation is also preferable Yes. By reducing the thickness of the discharge electrode to 100 m or less, it is possible to quickly recover from the heated state and to increase the printing speed.

[0011] As a heating means for heating the discharge electrode, any heating means that can selectively heat an arbitrary position of the discharge electrode may be used in close contact with the discharge electrode, or separated from the discharge electrode. It can be heated.

As a heating means for heating by being brought into close contact with the discharge electrode, a configuration similar to that of a thermal print head used in a conventional thermal facsimile can be suitably used. Specifically, the heat generation of the heating resistor is controlled by a driver IC electrically connected to the heating resistor.

As a heating means for heating away from the discharge electrode, a method of irradiating laser light, a method of irradiating infrared rays, or the like can be suitably used. As a method of irradiating laser light, a combination of a laser irradiation unit and a polygon mirror or a galvanometer mirror, a method of serially scanning the laser irradiation unit, or the like is preferably used.

[0012] As described above, in the heat discharge type print head, the discharge is performed in a state where an electric field is formed by setting a potential difference corresponding to the discharge control voltage between the discharge electrode and the counter electrode during the potential difference setting step. A discharge is generated by selectively heating the discharge electrode with the heating means based on the image information in the electrode heating process, but various waveforms are selected as the driving voltage applied to the discharge electrode. Triangular waves, rectangular waves, trapezoidal waves, sin waves, etc. can be used alone or in combination, and a DC voltage or an AC voltage can be superimposed on them. For example, in the head-side voltage application step of the potential difference setting step, positive and negative ions are generated when only an AC voltage is applied to the discharge electrode as a driving voltage. Therefore, in order to select only negative ions, a negative DC voltage is superimposed on the AC voltage, and to select only positive ions, the discharge voltage is obtained by using a positive DC voltage superimposed on the AC voltage as a driving voltage. Apply to.

At this time, even if the heating amount by the heating means is controlled to be constant, if the voltage value of the driving voltage applied to the discharge electrode at the time of heating is different, the amount of ions generated is different. When the value changes with time, such as a sine wave or a triangular wave, the timing for applying the driving voltage over the head side voltage application process and the discharge electrode heating temperature It is necessary to synchronize the timing for heating the discharge electrode. This is because it is possible to reduce variations in the amount of ions generated by always heating the discharge electrode at the same timing against the driving voltage that periodically changes with time.

[0013] It should be noted that if the temperature of the discharge electrode reaches a peak when the voltage value of the driving voltage reaches a peak, the discharge generation efficiency is maximized, and the generated amount of ions generated accordingly is also maximized. It becomes. If the temperature of the discharge electrode does not reach the peak when the voltage value of the driving voltage is at the peak, the discharge generation efficiency will decrease, but the discharge electrode will be above the predetermined temperature while the driving voltage is applied. As long as it is heated, ions can be generated. If the heating time by the heating means is widened so that the voltage value of the driving voltage reaches a peak during the heating time, variations in the amount of ions generated can be greatly reduced, and the driving voltage can be reduced. The timing of the peak value of the working voltage and the peak temperature of the discharge electrode need not necessarily coincide.

Further, when synchronizing the head side voltage application process and the discharge electrode heating process, either may be used as a reference.

[0014] The invention according to claim 2 is the method for driving the heat-discharge type print head according to claim 1, wherein a plurality of application of the drive voltage in the head side voltage application step is performed within one print cycle. It has a structure that repeats!

With this configuration, in addition to the operation of claim 1, the following operation is provided.

(1) By repeating the application of the driving voltage in the head-side voltage application process a plurality of times within one printing cycle, the heating by the heating means can be divided and repeated a plurality of times in synchronization with the application of the discharge amount. As the number of heating rises can be increased, the total amount of ions generated can be increased, and the discharge generation efficiency is excellent.

(2) —By controlling the number of times of applying the driving voltage repeatedly within the printing cycle, the ion generation amount can be controlled easily and accurately, and high-quality gradation recording can be performed.

(3) By repeating the application of the driving voltage multiple times within one printing cycle, the number of discharges can be increased to increase the total amount of ions generated, so the peak value of the driving voltage is reduced. Setting and heating time by the heating means and discharge generation time can be shortened as a whole, and the long life of the discharge electrode is excellent. Here, when the application of the driving voltage is repeated within one printing cycle in the head-side voltage application process, the discharge electrode heating process is performed in synchronization with the timing of applying each driving voltage. Controls the voltage value and application time of the driving voltage per time or the heating time by the heating means, and controls the number of times the heating voltage is applied and the heating voltage is repeated within one printing cycle. Thus, the amount of generated ions can be controlled.

[0016] The invention according to claim 3 is the driving method of the heat discharge type print head according to claim 1 or 2, wherein the driving voltage applied to the discharge electrode in the head side voltage applying step. The discharge electrode is heated by the discharge electrode heating step at the peak of the time.

With this configuration, in addition to the operation of the first or second aspect, the following operation is provided.

(1) At the peak of the driving voltage applied to the discharge electrode in the head side voltage application process, the discharge electrode is heated by the discharge electrode heating process, so that the discharge can be generated reliably. When the voltage peak and the temperature peak of the discharge electrode heated by the discharge electrode heating step are substantially matched, the maximum amount of ions can be generated, and the discharge generation efficiency is excellent.

[0017] Here, the heating in the discharge electrode heating step has a range of time, so that the discharge can be surely generated if the timing is adjusted so that the voltage value of the driving voltage reaches the peak during the heating time. Can do.

When the drive voltage peak and the discharge electrode temperature peak are substantially matched, the heating means power is turned on in consideration of the time until heat is transferred to the discharge electrode. It is necessary to set the timing earlier than the timing of the peak of the driving voltage applied to the discharge electrode. In addition, the heating ON timing force of the heating means The time (time lag) until the discharge electrode reaches a predetermined temperature varies depending on the thickness of the heat generating part insulating film, the thermal conductivity of the material, the heating temperature, etc. Therefore, adjust the timing appropriately according to these conditions.

[0018] The invention according to claim 4 is the heating discharge type print head driving method according to any one of claims 1 to 3, wherein the opposing force is synchronized with the head side voltage application step. A medium side voltage applying step for applying a part of the discharge control voltage to the electrode; ing.

With this configuration, in addition to the operation of any one of claims 1 to 3, it has the following operation.

(1) The drive voltage directly applied to the discharge electrode can be reduced by performing the medium-side voltage application step of applying a part of the discharge control voltage to the counter electrode in synchronization with the head-side voltage application step. In addition to excellent long life of the discharge electrode, it is possible to form a high-quality image by optimally adjusting the voltage value applied to the counter electrode according to the type and characteristics of the recording medium. .

(2) By synchronizing the medium-side voltage application process with the head-side voltage application process, it is possible to prevent voltage from being applied to the counter electrode in a non-printing state, and printing is interrupted or stopped due to problems or the like. In this case, the recording medium can be removed safely, and it is easy to maintain.

Here, since the potential difference between the discharge electrode and the counter electrode only needs to be within the range of the discharge control voltage, the voltage value to be applied to the discharge electrode and the counter electrode within the range is arbitrarily set. Can do.

As the voltage applied to the counter electrode, various waveforms can be selected in the same manner as the driving voltage applied to the discharge electrode. For example, when a part of the discharge control voltage in which the DC voltage is superimposed on the AC voltage is applied to the counter electrode, at least a part of the DC component may be distributed and applied to the counter electrode. Even if the part is distributed and applied to the counter electrode,

[0020] The invention according to claim 5 is the heating discharge type print head drive method according to any one of claims 1 to 4, wherein the discharge is performed during the head side voltage application step. It has a configuration in which an auxiliary voltage having a polarity opposite to that of the driving voltage is applied to the discharge electrode at least either before or after application of the driving voltage to the electrode.

With this configuration, in addition to the operation of any one of claims 1 to 4, the following operation is provided.

(1) In the head-side voltage application step, before applying the driving voltage to the discharge electrode, an auxiliary voltage having a polarity opposite to that of the driving voltage is applied to the discharge electrode, so that the surplus generated in the previous driving is generated. It is possible to attract and collect unnecessary electrons and ions to the discharge electrode before driving, thereby preventing image smearing and improving image quality.

(2) In the head side voltage application process, after applying the driving voltage to the discharge electrode, an auxiliary voltage having a polarity opposite to that of the driving voltage is applied to the discharge electrode, thereby driving excess electrons and ions generated by driving. It can be recovered immediately and prepared for the next drive (application of drive voltage), and is excellent in reliability that electrons and ions do not float even when the drive cycle is long.

[0021] Here, the auxiliary voltage may be a voltage that is small enough to attract excess electrons and ions to the discharge electrode! Even if an auxiliary voltage is applied and the discharge electrode is heated, the voltage value is set so that no discharge occurs even when the discharge electrode is heated, so that unnecessary electrons and ions are not generated and the reliability is excellent.

The invention's effect

[0022] As described above, according to the method for driving the heat discharge type print head of the present invention, the following advantageous effects can be obtained.

According to the invention described in claim 1, the following effects are obtained.

(1) For head side voltage application process! By synchronizing the timing of applying the driving voltage to the discharge electrode and the timing of selectively heating the discharge electrode in the discharge electrode heating process, the discharge is reliably generated and the variation in the amount of ions generated is reduced. Provides a method for driving a heat-discharge-type print head that has excellent image quality reliability, energy saving that prevents unnecessary voltage application to the discharge electrode, and excellent discharge electrode long life. be able to.

[0023] According to the invention described in claim 2, in addition to the effect of claim 1, the following effect is obtained.

(1) In the head-side voltage application process, the amount of ion generation can be easily and accurately controlled by controlling the number of times of application of the driving voltage repeated within one printing cycle, and image quality can be recorded with gradation. It is possible to provide a method for driving a heat-discharge type print head having excellent reliability.

(2) —Increase the number of discharges by repeating the application of drive voltage multiple times within the printing cycle. As a result, the number of heating rises in which the amount of discharge increases in synchronism with it can be increased, so that the total ion generation amount can be increased, and the peak value of the drive voltage can be set low or the heating can be performed. It is possible to provide a method for driving a heat-discharge type print head that can shorten the heating time and discharge generation time by the means and has a long life of the discharge electrode.

[0024] According to the invention of claim 3, in addition to the effect of claim 1 or 2, it has the following effect.

(1) By matching the timing of the discharge electrode heating process with the peak of the driving voltage in the head side voltage application process, heating can be performed while the maximum voltage is applied to the discharge electrode to generate discharge. In addition, it is possible to provide a method for driving a heat-discharge type print head that is excellent in the efficiency of ion generation.

[0025] According to the invention of claim 4, the effect of any one of claims 1 to 3 is achieved, and the following effects are obtained.

(1) By synchronizing the medium-side voltage application process with the head-side voltage application process, a potential difference corresponding to the discharge control voltage can be set reliably between the discharge electrode and the counter electrode, and applied directly to the discharge electrode. The drive voltage can be reduced to improve the durability of the discharge electrode, and a high-quality image can be formed by optimally adjusting the voltage applied to the counter electrode according to the type and characteristics of the recording medium. It is possible to provide a method for driving a heat-discharge type print head having excellent versatility.

[0026] According to the invention of claim 5, the effect of any one of claims 1 to 4 is reduced, and the following effects are obtained.

(1) In the head-side voltage application step, an extra voltage having a polarity opposite to that of the drive voltage is applied to the discharge electrode at least one of before or after application of the drive voltage to the discharge electrode. Electrons and ions can be attracted to the discharge electrode and collected immediately before or after driving, and the image quality can be reliably prevented from floating by preventing electrons and ions from floating. It is possible to provide a method for driving a heat-discharge type print head.

Brief Description of Drawings [0027] [Fig. 1] (a) A schematic side view showing a usage state of a heat discharge type print head. (B) A schematic perspective view of a main part showing a heat discharge type print head.

FIG. 2 is a schematic plan view of the head substrate of the heat discharge type print head in the first embodiment.

[Fig. 3] (a) Schematic cross-sectional view taken along line A-A in Fig. 2 (b) Schematic cross-sectional view taken along line B-B in Fig. 2

FIG. 4 is a schematic side view showing an image forming method using a heat discharge type print head.

FIG. 5 is a block diagram showing a configuration of a heat discharge type print head in the first embodiment.

[FIG. 6] (a) A diagram showing a driving voltage in a head-side voltage applying process of the heating discharge type print head driving method in Embodiment 1. (b) Driving of the heating discharge type print head in Embodiment 1. The figure which shows the temperature of the discharge electrode in the discharge electrode heating process of the method

[FIG. 7] (a) A diagram showing a driving voltage in a head-side voltage applying process of a heating discharge type print head driving method in Embodiment 2. (b) Driving of a heating discharge type print head in Embodiment 2. (C) Diagram showing the temperature of the discharge electrode in the discharge electrode heating step of the method for driving the heat discharge type print head in Embodiment 2 in the medium side voltage application step of the method

[FIG. 8] (a) A diagram showing a driving voltage in the head-side voltage applying process of the heating discharge type print head driving method in Embodiment 3. (b) Driving of the heating discharge type print head in Embodiment 3. (C) Diagram showing the temperature of the discharge electrode in the discharge electrode heating step of the method for driving the heat discharge type print head in Embodiment 3 in the medium side voltage application step of the method

[FIG. 9] (a) A diagram showing a driving voltage in a head-side voltage application process of a heating discharge type print head driving method in Embodiment 4. (b) Driving of a heating discharge type print head in Embodiment 4. The figure which shows the temperature of the discharge electrode in the discharge electrode heating process of the method

Explanation of symbols

[0028] 1 Heating discharge type print head

2 Heat sink

3a End face

4 head board

5 Discharge electrode 5a Electron emission site

5b Common electrode

6 Driver

7 Discharge control device

8 Printed circuit board

8a connector

9 IC cover

9a High voltage substrate

10 Flexible substrate

11a Comb electrode for heating

l ib Common electrode for heat generation

12 Individual electrode for heat generation

13 Heating means

13a Heating resistor

13b Heat-generating part insulation film

16 Conductive material layer

20 Recording media

21 Counter electrode

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1)

A method of driving the heat-discharge type print head in Embodiment 1 of the present invention will be described below with reference to the drawings.

First, the configuration of a heating / discharging printhead to which the heating / discharging printhead driving method according to the first embodiment is applied will be described.

FIG. 1 (a) is a schematic side view showing the usage state of the heating / discharge type print head, and FIG. 1 (b) is a schematic perspective view of the main part showing the heating / discharge type print head.

In FIG. 1, 1 is a heating discharge type print head to which the driving method of the heating discharge type print head according to Embodiment 1 of the present invention is applied, and 2 is a heating discharge type mark formed of a material such as aluminum. The heat sink of the character head 1, 3 a is a substantially arc-shaped end surface formed at the tip of the heat sink 2, 4 is a flexible substrate to be described later, and a discharge electrode 5, which will be described later, a heating resistor of the heating means, etc. are laminated to radiate heat The head substrate of the heat discharge type print head 1 disposed on the plate 2, 5 is the discharge electrode of the heat discharge type print head 1, 5 a is a plurality of electron emission sites of the discharge electrode 5 formed in a ladder shape, 5 b is A common electrode of the discharge electrode 5 connected to both ends of the plurality of electron emission sites 5a, 7 is a heating discharge type print head 1 having a head IC 4 and a driver IC 6 for controlling the heat generation of a heating resistor described later. Discharge control device 8 includes a connector 8a for connecting to an external control unit and a printed wiring board of the heat discharge type print head 1 disposed on the heat sink 2 9 protects the driver IC 6 and the printed wiring board 8 In order to perform 1 is an IC cover, 9a is a high voltage substrate that is disposed on the back of the IC cover 9 and is electrically connected to the common electrode 5b of the discharge electrode 5 and supplies a high voltage (discharge control voltage) to the electron emission site 5a. is there.

[0030] By disposing the high voltage substrate 9a on the back of the IC cover 9 and electrically connecting to the common electrode 5b of the discharge electrode 5, the electrical wiring for applying the discharge control voltage can be shortened, The high-pressure substrate 9a can be handled integrally with the heat-discharge type print head 1. This eliminates the need for electrical wiring, makes it easy to incorporate into an image forming apparatus, and excels in mass productivity. In particular, when an image is formed by scanning the heat-discharge type print head 1, the heat-discharge type print head 1 and the high-voltage board 9a can be moved together, so that it is difficult to place a load on the electric wiring. The occurrence of poor conduction can be reduced.

Note that the arrangement position of the high-voltage substrate 9a is not limited to the present embodiment, and it is sufficient that the discharge control voltage can be applied to the common electrode 5b of the discharge electrode 5.

Next, details of the structure of the head substrate will be described.

Fig. 2 is a schematic plan view of the head substrate of a heat discharge type print head. Fig. 3 (a) is a schematic cross-sectional view taken along the line AA in Fig. 2, and Fig. 3 (b) is a line B-B in Fig. 2. It is a cross-sectional schematic view. 2 and 3, 10 is a flexible substrate of the head substrate 4 made of a heat-resistant and insulating thin film resin such as polyimide, aramid, or polyetherimide, and 1 la is a comb-like shape on the upper surface of the substrate 10. The formed heating comb electrode, l ib is a heating common electrode formed in a substantially U-shape on the upper surface of the substrate 10 so as to connect the ends of the plurality of heating comb electrodes 11a, 12 Is a heating individual electrode formed on the upper surface of the substrate 10 alternately with a plurality of heating comb electrodes 11a, 13 is a heating means of the discharge control device 7, 13a is a heating comb electrode 11a and a heating individual electrode 12 A heating resistor 13 of the heating means 13 that is electrically connected to the heating element 13 and 13b is a heating part covered on the upper surface of the substrate 10 except for the ends of the heating common electrode l ib and the heating individual electrode 12. An insulating film 16 is a conductive material layer formed on the surface of the common electrode 5b in the discharge electrode 5.

Note that the discharge electrode 5 is insulated from the heating comb electrode l la, the heating individual electrode 12 and the heating resistor 13a by the heating portion insulating film 13b, and a plurality of electron emission portions 5a of the discharge electrode 5 are insulated. Is formed to face the heat generating resistor 13a at a position corresponding to the heat generating individual electrode 12. The heat generating portion insulating film 13b has heat resistance and insulating properties, and insulates between the discharge electrode 5 and the heating means 13. In order to ensure insulation, an insulating film may be formed on at least one of the two surfaces of the heat generating portion insulating film 13b. Insulating film is made of inorganic materials such as SiON and SiO

2

It can be formed into a thin film with an insulating material (whether organic or inorganic). In particular, a material having high thermal conductivity that can efficiently transfer the heat of the heating resistor 13a to the electron emission site 5a is preferable.

[0033] The conductive material layer 16 was formed of silver paste or the like having excellent conductivity. By forming the conductive material layer 16 on the surface of the common electrode 5b, the resistance value of the common electrode 5b can be lowered, and the potential difference generated between the respective electron emission sites _5a can be reliably reduced.

In the present embodiment, the conductive material layer 16 is formed on each of the two common electrodes 5b, but may be formed on only one of them. The conductive material layer 16 may be formed on a part of the common electrode 5b as shown in FIGS. 2 and 3, or may be formed over the entire width. Further, the conductive material layer 16 may be formed at a location other than the electron emission site 5 a of the discharge electrode 5.

By disposing the heat radiating plate 2 on the head substrate 4, the heat generated by the heating means 13 can be quickly absorbed by the heat radiating plate 2 and radiated from the heat radiating plate 2. As a result, the heating means 13 can be rapidly cooled to improve the response to the heating stop. In addition, it can protect the driver IC6 etc. from heat and has excellent reliability. When irregularities are formed on the surface of the heat radiating plate 2 by grooves or the like, the surface area of the heat radiating plate 2 can be increased, and the efficiency of heat radiation can be improved. The heating resistor 13a was heated at a low voltage of 24V, and the driver IC 6 used as a switch for generating heat from the heating resistor 13a was a 5V drive compatible with low withstand voltage. The driver IC 6 was wire bonded to the lead pattern extending from the heating means 13 with a gold wire, and then sealed with an IC protecting resin such as epoxy resin.

Next, a method for manufacturing the head substrate will be described in detail.

First, a heating part formation process is demonstrated.

2 and 3, a plurality of heat generating comb-teeth electrodes 11a connected by heat generating common electrodes l ib after printing a conductor such as a gold paste on the surface of the flexible substrate 10 formed in a flat shape. And the individual electrode 12 for heat generation is formed. After that, a strip-like shape is printed by printing TaSiO, RuO, etc. on the top of the heating comb electrode 11a and the heating individual electrode 12.

twenty two

A heating resistor 13a is formed.

[0036] In the present embodiment, the heating resistor 13a of the heating means 13 is formed in a strip shape, the heating comb electrodes 11a and the heating individual electrodes 12 are alternately arranged, and one heating heater at each center is provided. By energizing between the individual electrode 12 and the comb electrode 11a for heat generation on both sides thereof, any part of the heating resistor 13a corresponding to the position of each electron emission part 5a is selectively heated, and the electron emission part The force used to heat 5a is not limited to this, and any structure that can selectively heat each electron emission portion 5a is acceptable. The configuration of the heating means 13 may be a thick film type or a thin film type.

[0037] Next, the discharge electrode forming step will be described.

2 and 3, the surface of the flexible substrate 10 except for the ends of the heat generating common electrode l ib and the heat generating individual electrode 12 has a heat resistance and insulation properties of about 300 ° C on the surface of the flexible substrate 10. The heat generating portion insulating film 13b is formed by printing a thin film resin such as ether imide. The heat generating portion insulating film 13b may be any material that can protect and insulate the heat generating common electrode l lb, the heat generating individual electrode 12, the heat generating resistor 13a, etc., but the heat of the heat generating resistor 13a is efficiently discharged 5 Those having a high thermal conductivity capable of being transmitted to are preferably used. The heat generating portion insulating film 13b may be formed by applying a heat-resistant and insulating resin solution such as polyimide garamide by screen printing or the like, or a thin film sheet formed of the same resin. A cover may be formed. Next, a plurality of electron emission portions 5a facing the heat generating individual electrodes 12 of the heating means 13 and a common electrode 5b connecting them are formed on the heat generating portion insulating film 13b. For the formation of the electron emission portion 5a and the common electrode 5b, a material such as gold, silver, copper, aluminum, or the like, which is formed by vapor deposition or notter printing and then etched to form a pattern is suitably used. . In addition, a conductive material such as carbon may be used.

In the present embodiment, the electron emission site 5a is formed in a substantially rectangular shape, but can be formed in a trapezoidal shape, a shell shape, a semicircular shape, or a combination of these. In addition, since the discharge electrode 5 has a large amount of discharge due to the peripheral edge force, a plurality of irregularities are formed on the outer peripheral edge of the electron emission site 5a to increase the peripheral length of the peripheral edge, thereby improving the discharge generation efficiency. It can be made. As a result, the amount of discharge from the electron emission site 5a is increased, and the amount of ion irradiation and emission intensity can be increased, so that the energy saving property of the discharge control device 7 is excellent. In addition, since the voltage applied to the discharge electrode 5 can be set small, the life of the discharge electrode 5 is excellent.

[0039] The thickness of the flexible substrate 10 of the head substrate 4 and the heat generating part insulating film 13b is extremely thin, for example, several / zm to several tens / zm. Can be formed to be extremely thin with a thickness of about several tens / zm to several hundreds / zm. Although the head substrate 4 is formed in a flat state, it is extremely thin and flexible, so it can be easily processed (deformed) by bending it from the flat state according to the shape of the end surface 3a of the heat sink 2. Therefore, it is possible to obtain a heat discharge type print head 1 that is not subject to restrictions on the formation technology of the discharge electrode 5, the heating means 13, and the like. In addition, the head substrate 4 remains the same, and the heat discharge type print head 1 can be obtained in various forms simply by changing the shape of the heat sink 2 and the attachment position of the head substrate 4. Excellent mass productivity.

The basic operation of the heat discharge type print head formed as described above will be described. FIG. 4 is a schematic side view showing an image forming method using the heat discharge type print head. In FIG. 4, 20 is an electrostatic development type recording medium that can repeatedly write and erase images by the action of electric charge, and 21 is a counter electrode formed on, or in contact with, or close to the back side of the recording medium 20. is there. First, in the potential difference setting step, as shown in FIG. 4, the discharge control voltage E (discharging does not occur only when applied) between the discharge electrode 5 and the counter electrode 21 of the heat discharge type print head 1.

0

However, the electric field is formed by setting a potential difference corresponding to the voltage range in which discharge occurs when heated. The potential difference setting unit that sets the potential difference between the discharge electrode 5 and the counter electrode 21 includes a head-side voltage application unit that applies a voltage to the discharge electrode 5, and a selective grounding or voltage application to the counter electrode 21. A device provided with a medium-side voltage control unit is preferably used. The discharge control voltage E is applied to the discharge electrode 5 by the head side voltage application unit, and the medium side voltage control unit

0

The counter electrode 21 may be grounded by a discharge control voltage E and the discharge electrode 5

0

It may be distributed and applied to the counter electrode 21. As a result, the voltage value applied to the counter electrode 21 can be adjusted according to the type of the recording medium 20, and the discharge on the discharge electrode 5 side can be reduced and discharge can be generated efficiently. .

[0041] Next, in the discharge electrode heating step, the discharge control voltage E is applied to the discharge electrode 5 (common electrode 5b).

In a state where a voltage of 0 or less is applied, the heating means 13 is controlled by the driver IC6, and the electron emission site 5a is selectively heated (100 to 300 ° C.) by the heating resistor 13a of the heating means 13. It is possible to generate a discharge between the electron emission site 5a of the discharge electrode 5 and the counter electrode 21 that are arranged to face each other. Then, the electrons and ions emitted from the electron emission site 5a of the discharge electrode 5 by the electric field can be moved to the recording surface (surface) of the recording medium 20, and an image can be formed by applying charges. By selecting the heating location by the heating means 13, it is possible to easily emit electrons by selectively emitting electrons from any electron emission site 5a of the discharge electrode 5 (see FIGS. 2 and 3). .

[0042] As described above, in the heating and discharging type print head 1, the presence or absence of discharge can be controlled by controlling the presence or absence of heating of the discharge electrode 5 to which a voltage is applied. The amount of ions generated varies depending on the voltage and the temperature of the discharge electrode 5. Therefore, in order to control the amount of ions generated, it is necessary to control the timing of applying a driving voltage to the discharge electrode 5 and the timing of heating the discharge electrode 5 by the heating means 13 and the amount of heating by the heating means 13.

The details of the method for driving the heat-discharge type print head in Embodiment 1 will be described below. FIG. 5 is a block diagram showing the configuration of the heat discharge type print head according to the first embodiment. In FIG. 5, the heating means 13 of the heat discharge type print head 1 includes heat generation points corresponding to n electron emission sites 5 a. A heating resistor 13a having Rl to Rn and a driver IC 6 that is electrically connected to the heating resistor 13a and controls the heat generation of the heating resistor 13a are provided.

The driver IC 6 includes a shift register unit, a latch unit, an output gate unit, and output transistors Q1 to Qn. Signals are also input to each part through the cable connected to the connector 8a (see Fig. 1).

A DC power supply voltage VHD for driving the heating resistor 13a is applied to the heating common electrode l ib (see FIGS. 2 and 3) common to the heating points Rl to Rn of the heating resistor 13a. Image data (image information) is input to a shift register unit synchronized with a clock signal Clock as one line of serial data Serial in rather than parallel data. These image data are transferred to the latch unit at the timing of the latch signal Latch. The output gate unit turns on the output transistors Ql to Qn for the time when the strobe signal Strobe is at the L level for the heat generation points Rl to Rn where the output level of the latch unit is the H level. As a result, the heat generation points Rl to Rn generate heat corresponding to the H level of the image data. At this time, since a driving voltage is applied from the high-voltage substrate 9a to the discharge electrode 5 based on the strobe signal Strobe, the discharge electrode 5 has a discharge control voltage equal to or less than the discharge control voltage during the head side voltage application step of the potential difference setting step. The timing for applying the driving voltage can be synchronized with the timing of the discharge electrode heating step in which the discharge means 5 is selectively heated by the heating means 13. If it is necessary to shift the timing of applying the driving voltage with respect to the timing of heating the discharge electrode 5 in consideration of the thermal conductivity of the heat generating part insulating film 13b, etc., it is delayed in the high voltage substrate 9a. A circuit may be provided.

Since the strobe signal Strobe is turned on only when there is data, the number of ons within one printing cycle can be controlled by the number of data. Therefore, depending on the density of the image (1 dot), it is possible to change the number of times the heating voltage is applied by applying the driving voltage to the discharge electrode 5 and the heating means 13 within one printing cycle, thereby changing the amount of generated ions. Therefore, the charge amount in the recording medium 20 can be controlled, and gradation recording can be easily performed. 5 is merely an example of a configuration in which a heating resistor 13a is used as the heating means 13, and means for synchronizing the timing of the head-side voltage application process and the discharge electrode heating process or the heating means 13 Is not limited to this.

FIG. 6 (a) is a diagram showing a driving voltage in the head-side voltage application process of the heating and discharging type print head driving method in the first embodiment, and FIG. 6 (b) is a diagram in the first embodiment. FIG. 5 is a diagram showing the temperature of the discharge electrode in the discharge electrode heating step of the heating / discharging type print head driving method.

First, the head side voltage application step of the potential difference setting step will be described.

The driving voltage is applied to the discharge electrode 5 from the high voltage substrate 9a (see FIG. 1) connected to the common electrode 5b. In this embodiment, the driving voltage applied to the discharge electrode 5 can be considered in various combinations. As shown in FIG. 6 (a), a DC bias is superimposed on the triangular wave, and the peak value is the discharge control voltage E. Repeated several times within one printing cycle T (3 times in Fig. 6).

0

Applied repeatedly. At this time, the counter electrode 21 is grounded.

[0046] Next, the discharge electrode heating step will be described.

In the discharge electrode heating step, the force for selectively heating the discharge electrode 5 by the heating means 13 is synchronized with the timing of applying the driving voltage in the head side voltage applying step, as shown in FIG. Do.

At this time, the temperature of the discharge electrode 5 heated by the discharge electrode heating step is at the peak at the peak of the drive voltage (E) applied to the discharge electrode 5 in the head side voltage application step.

0

The timing was adjusted. By adjusting the timing so that the voltage value of the driving voltage reaches the peak (E) while the temperature of the discharge electrode 5 is at the peak, efficient discharge is generated.

0

It is because it can be made. The ion generation amount (charge amount) changes almost in proportion to the temperature of the discharge electrode 5 shown in FIG. 6 (b). Actually, the heat transfer to the discharge electrode 5 varies depending on the thickness of the heat-generating part insulating film 13b and the thermal conductivity of the material, so the heating ON timing to the heating means 13 in the discharge electrode heating process And drive voltage peak (E)

0 It is preferable that the heating means 13 accelerate the heating by shifting the time lag of the heat transfer. Further, in the head-side voltage application process, the driving voltage is applied several times within one printing cycle T. When applying (three times in FIG. 6), heating by the heating means 13 is performed in synchronization with the timing of applying each driving voltage. Controls the voltage value and application time of the driving voltage per time or the heating time by the heating means 13, and controls the number of times the driving voltage is applied and the heating means 13 is repeated within one printing cycle T. As a result, the amount of ion generation can be controlled, and gradation recording can be easily performed.

The method for driving the heat-discharge type print head according to the first embodiment is configured as described above, and thus has the following effects.

(1) Corresponds to the discharge control voltage E between the discharge electrode 5 and the counter electrode 21 in the potential difference setting process.

0

By setting the potential difference to be generated and preparing an electric field, it is possible to prepare for the discharge, and it is possible to generate a discharge simply by selectively heating the discharge electrode 5 based on the image information in the discharge electrode calorie heating process. Therefore, it is not necessary to control a high voltage, and the generation of discharge can be easily controlled.

(2) During the head-side voltage application process, the timing of applying the driving voltage to the discharge electrode 5 and the timing of selectively heating the discharge electrode 5 in the discharge electrode heating process are synchronized to ensure reliable discharge. As a result, it is possible to reduce the variation in the amount of ions generated, and the image quality is highly reliable, and an unnecessary voltage is not applied to the discharge electrode 5 and energy saving is excellent.

(3) By repeating the application of the driving voltage in the head side voltage application process a plurality of times within one printing cycle, the heating by the heating means 13 can be divided and repeated a plurality of times in synchronization with it, Since the number of heating rises that increase the amount of discharge can be increased, the total amount of ions generated can be increased and the efficiency of discharge generation is excellent.

(4) The amount of ion generation can be easily and accurately controlled simply by controlling the number of times of applying the driving voltage repeated within one printing cycle T, and high-quality images can be formed by gradation recording.

(5) By repeating the application of the driving voltage multiple times within one printing cycle T, the number of discharges can be increased and the total amount of generated ions can be increased, so the peak of the driving voltage can be increased. Set the value (E) low, the heating time by the heating means 13 and the discharge occurrence time. As a whole, it can be shortened, and the long life of the discharge electrode is excellent.

(6) At the peak of the driving voltage applied to the discharge electrode 5 in the head side voltage application process, the discharge electrode 5 can be heated by the discharge electrode heating process to reliably generate a discharge. When the peak of the driving voltage and the temperature peak of the discharge electrode 5 heated by the discharge electrode heating step are substantially matched, the maximum amount of ions can be generated, and the discharge generation efficiency is excellent.

[0048] (Embodiment 2)

A method for driving the heat-discharge type print head according to the second embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 (a) is a diagram showing a driving voltage in the head side voltage application process of the heating discharge type print head driving method in the second embodiment, and FIG. 7 (b) is a heating discharge in the second embodiment. FIG. 7 (c) is a diagram showing a voltage applied to the counter electrode in the medium-side voltage application step of the method for driving the mold print head, and FIG. It is a figure which shows the temperature of the discharge electrode in a process. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In FIG. 7, the driving method of the heat discharge type print head in the second embodiment is different from that in the first embodiment in that discharge control is performed on the counter electrode 21 in synchronization with the head side voltage application process in the potential difference setting process. This is a point having a medium side voltage applying step for applying a part of the voltage E.

0

At this time, the peak of the potential difference between the discharge electrode 5 and the counter electrode 21 is the discharge control voltage E.

The relationship of E−E = E is established between the peak value E of the driving voltage applied to the discharge electrode 5 and the voltage E applied to the counter electrode 21.

2 1 2 0

Thus, the discharge control voltage E force discharge set between the discharge electrode 5 and the counter electrode 21

Except for being distributed and applied to the electrode 5 and the counter electrode 21, they are the same as in the first embodiment, and thus description thereof is omitted.

In the present embodiment, only a part of the force applied to the counter electrode 21 may be applied to the voltage E corresponding to the DC bias component of the driving voltage in the first embodiment.

2

[0050] The method for driving the heat-discharge-type print head according to the second embodiment is configured as described above. Therefore, in addition to the operation of the first embodiment, the following operation is provided. (1) A part of the discharge control voltage E is applied to the counter electrode 21 in synchronization with the head side voltage application process.

By performing the medium-side voltage application process to be applied, the driving voltage E directly applied to the discharge electrode 5 can be reduced, and the discharge electrode 5 has excellent long life and the type of the recording medium 20 High quality by optimally adjusting the voltage value E applied to the counter electrode 21 according to the characteristics etc.

2

An excellent image can be formed.

[0051] (Embodiment 3)

A method for driving the heat-discharge type print head according to the third embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 (a) is a diagram showing a driving voltage in the head side voltage application process of the heating discharge type print head driving method in the third embodiment, and FIG. 8 (b) is a heating discharge in the third embodiment. FIG. 8 (c) is a diagram showing a voltage applied to the counter electrode in the medium side voltage application process of the driving method of the print head, and FIG. 8 (c) shows the discharge electrode heating of the driving method of the heating and discharging print head in the third embodiment. It is a figure which shows the temperature of the discharge electrode in a process. The same components as those in the first or second embodiment are denoted by the same reference numerals and description thereof is omitted.

In FIG. 8, the heating discharge type print head driving method in the third embodiment is different from that in the second embodiment in that the voltage applied to the counter electrode 21 in the medium side voltage applying step is not DC bias. The peak value is the triangular wave of E.

Four

0, the peak value E of the driving voltage applied to the discharge electrode 5 and the counter electrode 21 are marked.

Three

The relationship of E− E = E is established with the applied voltage E.

4 3 4 0

The description is omitted because it is the same as in Embodiments 1 and 2 except that the voltage is distributed and applied to the electrode 5 and the counter electrode 21.

Note that the peak value E of the driving voltage applied to the discharge electrode 5 and the counter electrode 21 are applied.

Three

The ratio to the voltage E can be selected as appropriate according to the type and characteristics of the recording medium 20.

Four

The

[0053] The driving method of the heat-discharge type print head of the third embodiment is configured as described above. Therefore, in addition to the operation of the second embodiment, the following operation is provided. (1) When the media side voltage application process is synchronized with the head side voltage application process so that no voltage is applied to the counter electrode 21 in the non-printing state, when printing is interrupted or stopped due to a malfunction or the like. Therefore, the recording medium 20 can be removed safely, and the maintenance is excellent.

(2) Since the voltage applied to the counter electrode 21 is a triangular wave, the amount of ions generated can be controlled in synchronism with the driving voltage, and the gradation is excellent.

[Embodiment 4]

A method for driving a heat-discharge type print head according to Embodiment 4 of the present invention will be described below with reference to the drawings.

FIG. 9 (a) is a diagram showing a driving voltage in the head side voltage application process of the heating discharge type print head driving method in the fourth embodiment, and FIG. 9 (b) is a heating discharge in the fourth embodiment. FIG. 6 is a diagram showing the temperature of the discharge electrode in the discharge electrode heating step of the method for driving the mold print head. In addition, the same code | symbol is attached | subjected to the thing similar to Embodiment 1, and description is abbreviate | omitted.

In FIG. 9, the driving method of the heat discharge type print head in the fourth embodiment is different from that in the first embodiment in that the driving voltage applied to the discharge electrode 5 in the head side voltage applying step is a rectangular wave. One point is that an auxiliary voltage having a polarity opposite to that of the driving voltage is applied to the discharge electrode 5 after application of the driving voltage.

At this time, the auxiliary voltage may be a voltage (E) that is small enough to attract excess electrons and ions generated by the discharge to the discharge electrode 5. Auxiliary voltage is applied

Five

Set the voltage value E so that no discharge occurs even if the discharge electrode 5 is heated in this state.

Therefore, it is excellent in reliability without generating unnecessary electrons and ions.

The embodiment except that the auxiliary voltage is applied after the driving voltage is applied as described above.

The explanation is omitted because it is the same as 1.

In the present embodiment, the auxiliary voltage is applied after the driving voltage is applied to the discharge electrode 5, but the auxiliary voltage may be applied before the driving voltage is applied. Also, discharge control voltage

Instead of applying all the voltages corresponding to E to the discharge electrode 5 as drive voltages,

0

A part thereof may be applied to the counter electrode 21 as in the second embodiment.

[0056] The method of driving the heat-discharge-type print head according to the fourth embodiment is configured as described above! Therefore, in addition to the operation of the first embodiment, the following operation is provided.

(1) By applying a driving voltage to the discharge electrode 5 after applying a driving voltage to the discharge electrode 5 in the head-side voltage application step, extra electrons and ions generated by driving It is recovered immediately after driving and can be prepared for the next driving (application of driving voltage), and it has excellent reliability because electrons and ions do not float even when the driving cycle is long.

Industrial applicability

In the present invention, by controlling the timing of applying a voltage to the discharge electrode and the timing of heating the discharge electrode, it is possible to efficiently generate a discharge, which is excellent in energy saving and accurately controls the amount of ions generated. By providing a method for driving a heat-discharge type print head that can easily perform gradation recording and can form a high-quality image with high resolution, an electrostatic development type recording medium is provided. Can be promoted.

Claims

The scope of the claims

[1] A discharge electrode having an electron emission site and a heating discharge type print head having a heating means for selectively heating the discharge electrode, and the discharge electrode sandwiched by a recording medium capable of writing and erasing by the action of electric charge A potential difference setting step in which an electric field is set by setting a potential difference corresponding to the discharge control voltage between the counter electrode and the counter electrode disposed opposite to the counter electrode, and the heating means selectively selects the discharge electrode based on image information. A discharge electrode heating step for heating, a timing for applying a driving voltage equal to or lower than the discharge control voltage to the discharge electrode over the head side voltage application step of the potential difference setting step, and the discharge electrode heating step A method for driving a heat-discharge type print head, characterized in that the timings of these are synchronized.

[2] The method for driving a heat-discharge type print head according to [1], wherein the application of the driving voltage in the head side voltage applying step is repeated a plurality of times within one printing cycle.

3. The discharge electrode is heated by the discharge electrode heating step when the driving voltage applied to the discharge electrode is peaked in the head side voltage application step. A driving method of the heating and discharging type print head described in the above.

[4] The medium side voltage applying step of applying a part of the discharge control voltage to the counter electrode in synchronization with the head side voltage applying step is performed. 2. A method for driving a heat-discharge type print head according to item 1.

[5] In the head-side voltage application step, an auxiliary voltage having a polarity opposite to that of the drive voltage is applied to the discharge electrode either before or after application of the drive voltage to the discharge electrode. 5. The method for driving a heat discharge type print head according to claim 1, wherein the heating is applied.