JP2009113322A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method excelling in resource-saving property by considerably reducing voltage applied to an electric discharge electrode or dispensing with application of voltage to the electric discharge electrode to facilitate control while improving the durability and long service life of the electric discharge electrode. <P>SOLUTION: The image forming method comprises a potential difference setting process for forming a potential difference equivalent to a discharge control voltage between a dielectric layer of an electrostatic latent image carrier and the electric discharge electrode of a heat-discharge type printing head; a latent image forming process for forming an electrostatic latent image on the surface of the dielectric layer of the electrostatic latent image carrier by selectively heating the electric discharge electrode of the heat discharge type printing head based on image information to generate electric discharge; a developing process for developing the electrostatic latent image to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier; and a transfer process for transferring the visible image to a recording medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming method and an image forming apparatus for forming an image by developing an electrostatic latent image formed on an electrostatic latent image carrier using a heat discharge type print head.

  In the ion irradiation methods of (Patent Document 1) to (Patent Document 3), a discharge is not generated when only applied to a discharge electrode, but a voltage that generates a discharge by heating (discharge control voltage) is applied. This is a heating and discharge method that controls the presence or absence of discharge by controlling the presence or absence of heating to the electrode, and can control the generation of ions. The voltage can be applied to the entire discharge electrode at the same time. There is no need to individually control on / off of the voltage applied to the electrodes. As a result, it is possible to control the occurrence of discharge with a driver IC that supports low withstand voltage such as 5V drive used for controlling heating by a heating resistor or the like, and is the most excellent control method from the viewpoint of discharge control. It can be said that there is.

According to this ion irradiation type (heat discharge type) print head, an electrostatic development type recording medium that displays an image by the action of an electric charge (electrostatic latent image) applied to the surface, as represented by digital paper. On the other hand, since an electrostatic latent image can be directly formed by ion irradiation, it is an optimum print head that can be considered at present for writing in a non-contact manner on an electrostatic development recording medium.
In addition, as an application of an electrostatic latent image forming method using an ion irradiation method (Patent Document 3), an electrostatic latent image formed on the surface of an electrostatic latent image carrier by ion irradiation is developed. An image in which a visible image is formed on the surface of the electrostatic latent image carrier by a visualization means using toner, ink, etc., and the visible image is transferred to a printing medium such as plain paper or an OHP sheet by a transfer means. A forming apparatus has also been proposed.
Japanese Patent No. 3725092 WO2005-056297 Japanese Patent No. 3936726

(Patent Document 1) to (Patent Document 3), when heating is performed using a heating resistor in order to control the presence or absence of discharge by selectively heating a discharge electrode to which a voltage is applied by a heating means, It is necessary to reliably insulate between the discharge electrode and the heating resistor, and the insulating film is required to have high insulating properties, which requires man-hours for manufacturing, and improvement in mass productivity and yield has been desired.
In addition, if the insulating film is made thick in order to achieve high insulation properties, it takes time to transfer heat, and it is difficult to quickly switch between occurrence of discharge and it is difficult to increase the printing speed. Had.

  The present invention meets the above-mentioned conventional demands, and can greatly reduce the voltage applied to the discharge electrode or eliminate the need to apply the voltage to the discharge electrode. Providing an image forming method with excellent resource saving that can improve the lifespan, and even when heating the discharge electrode using a heating means such as a heating resistor, high insulation is provided between the heating means and the discharge electrode. It is unnecessary and can improve the yield by simplifying the process of forming the insulating film, excellent in mass production and long life, hardly change over time in the discharge amount from the heat discharge type print head, The purpose of the present invention is to provide an image forming apparatus that is excellent in reliability and stability, has excellent heat transfer from the heating means to the discharge electrode, and is capable of quickly switching whether or not discharge occurs. To do.

In order to solve the above problems, an image forming method and an image forming apparatus of the present invention have the following configurations.
The image forming method according to claim 1 of the present invention includes a potential difference setting step of forming a potential difference corresponding to a discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat discharge type print head. A latent image that forms an electrostatic latent image on the surface of the dielectric layer of the electrostatic latent image carrier by selectively heating the discharge electrodes of the heat-discharge type print head based on image information to generate a discharge; A forming step, a developing step of developing the electrostatic latent image to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier, and a transferring step of transferring the visible image to a recording medium. It has the structure provided with.
This configuration has the following effects.
(1) In the potential difference setting step, a potential difference corresponding to a discharge control voltage is formed between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head, so that the latent image can be prepared. Since the discharge can be generated simply by selectively heating the discharge electrodes of the heat-discharge type print head based on the image information in the forming process, it is not necessary to control the high voltage, and the generation of the discharge can be controlled easily. An electrostatic latent image can be formed on the surface of the dielectric layer of the electrostatic latent image carrier.
(2) In the potential difference setting step, voltage is applied to the discharge electrode or grounded, or the dielectric layer is charged, so that there is a gap between the discharge electrode of the heat discharge type print head and the dielectric layer of the electrostatic latent image carrier. Can be set to be equal to the discharge control voltage, the adjustment of the potential difference is easy, and the degree of freedom in setting the potential difference can be improved.
(3) The electrostatic latent image can be developed by the developing process to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier, and the visible image is transferred to the printing medium and recorded in the transferring process. In addition to plain paper, various media such as OHP sheets and glossy paper can be used as printing media, and the versatility is excellent.

Here, the heat discharge type print head forms a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat discharge type print head in the potential difference setting step, and the latent image. Since the generation of discharge can be controlled by selectively heating the discharge electrode in the forming step, the discharge electrode heating step is performed as a subsequent step of the potential difference setting step.
The discharge control voltage is a voltage range in which discharge does not occur only by the potential difference, but discharge occurs by heating the discharge electrode, and varies depending on the material of the discharge electrode, the surrounding environment, and the like. When the discharge space formed by separating the discharge electrode and the dielectric layer is an atmosphere capable of generating ions such as the atmosphere, the emitted electrons ionize oxygen and nitrogen and reach them to the surface of the dielectric layer. The electrostatic latent image can be efficiently formed with a large amount of ions.

For example, the discharge electrodes can be formed in a comb shape by connecting one end portions of a plurality of discharge generation portions with a common electrode, or can be formed in a ladder shape or the like by connecting both end portions of the plurality of discharge generation portions with a common electrode. In addition, it can be formed in a single flat plate shape such as a rectangular shape or a square shape (see, for example, Japanese Patent Application Laid-Open No. 2003-326756, WO 2005/056297).
By providing a common electrode in the vicinity of the discharge generating part, such as a comb type or a ladder type, the cooling effect of the discharge electrode and the response to heating stop are improved by increasing the heat radiation area of the discharge electrode and increasing the heat capacity. Since a stable voltage can always be applied by reducing the resistance value, the discharge stability and the like can be further improved. In addition, the discharge electrode formed in flat form becomes a common electrode except a discharge generation | occurrence | production part.
In particular, when the width of the common electrode is wider than the width of the discharge generating portion, the cooling effect of the discharge electrode that is temporarily heated to 100 to 300 ° C. is improved, and heat can be prevented from being heated. It is possible to quickly stop the discharge in response to turning OFF, to shorten the discharge time interval and to switch the presence or absence of discharge in a short time, and to increase the recording speed. In addition, the resistance value of the common electrode can be reduced, and the potential difference generated between the discharge generation units connected by the common electrode can be suppressed as much as possible, thereby reducing variations in the amount of electron emission in each discharge generation unit. And has excellent discharge stability.

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, etc., and then patterning to form a discharge generating part or a common electrode by etching as necessary. After thinning at least a part of a metal such as stainless steel, copper, or aluminum by etching or cutting, a pattern for forming a discharge electrode by etching or laser processing or the like is suitably used as necessary. 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. In addition, when heating is performed from the back side of the substrate by the heating means, those having heat transfer properties that can transfer heat generated by the heating means to the discharge electrode are preferably used. Specifically, synthetic resins such as glass, polyimide, aramid, and polyetherimide are preferably used.

When the discharge electrode is formed in a comb shape, the shape of each discharge generating portion can be formed in a substantially rectangular shape, trapezoidal shape, semicircular shape, bullet shape, or a combination thereof. Further, the peripheral length around the edge of the discharge generating portion can be increased by further dividing a part of the discharge generating portion with a slit or the like, or by forming an uneven portion on the peripheral portion (for example, WO2005 / 056297). reference). Since the discharge electrode has a large amount of electron emission 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 from the discharge electrode by increasing the circumference around the edge. In addition, the discharge control voltage and the heating temperature can be set low, and the energy saving and the efficiency of discharge generation are excellent. Moreover, since the discharge control voltage can be set low, the long life of the discharge electrode is also excellent.
Instead of dividing the end portion of the discharge electrode or forming the concavo-convex portion at the peripheral edge portion, a discharge hole portion may be formed in the vicinity of the discharge generating portion (heating position). Thereby, electrons can be emitted from the periphery of the edge of the discharge hole, and the same effect as that obtained by 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 polygon such as a quadrangle and a hexagon, and a star shape. Further, the number and size of the discharge hole portions per location of the discharge generation portion (near the heating position) can be appropriately selected and combined. In addition, the uneven | corrugated | grooved part and discharge hole part of a discharge electrode can be formed by the above-mentioned etching, laser processing, etc.

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 the respective discharge generating portions 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 screen printing of silver paste 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.
Although the thickness of the discharge electrode depends on the material, the thickness when formed of gold is preferably 0.1 μm to 100 μm. As the discharge electrode becomes thinner than 0.1 μm, it tends to be affected by wear, and the life of the discharge electrode tends to be shortened. As the discharge electrode becomes thicker than 100 μm, the heat capacity increases and the response to heating on / off decreases. There is a tendency to become easy and neither is preferable. By setting the thickness of the discharge electrode to 100 μm or less, it is possible to quickly recover from the heated state, and it is possible to increase the printing speed.

Any heating means for heating the discharge electrode may be used as long as it can selectively heat an arbitrary position (discharge generation portion) of the discharge electrode, and may be one that heats the discharge electrode in close contact with an insulating layer. Alternatively, heating may be performed separately from the discharge electrode.
As a heating means that heats the discharge electrode in close contact with the insulating layer, 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 this heating resistor, TaSiO ₂ , RuO ₂ or the like is preferably used.
As the material of the insulating layer that insulates the discharge electrode from the heating resistor, a material having insulation and heat resistance that can withstand the heating by the heating means and heat transfer that can transfer the heat generated by the heating means to the discharge electrode is preferable. Used for. Specifically, synthetic resins such as glass, polyimide, aromatic polyamide, polyphenylene oxide, polybenzimidazole, polyphenylquinoxaline, polyarylate, polyetherimide, polyethersulfone, polyphenylenesulfide, polyetheretherketone, aramid, etc. Preferably used.

  As a heating means for heating away from the discharge electrode, one having a light irradiation part such as a method of irradiating laser light or a method of irradiating infrared rays can be suitably used. As a light irradiating part for irradiating laser light, a laser irradiating part is combined with an optical scanning part such as a polygon mirror or a galvanometer mirror to scan only the laser light with respect to the discharge electrode. For example, a device that serially scans the laser irradiation unit itself is preferably used. Further, laser light or infrared light may be condensed by an optical fiber or a condensing lens and irradiated to the discharge electrode. In particular, when an optical fiber array in which a large number of optical fibers are arranged with high density and high accuracy is used, laser light and infrared rays can be selectively irradiated to the discharge generating portions of a plurality of discharge electrodes at the same time, enabling high-speed recording. Is possible. At this time, each optical fiber and the discharge electrode (discharge generation part) may be made to correspond one to one, and the exit tip of the optical fiber may be fixed to the discharge electrode. Alternatively, the discharge electrode can be formed by directly depositing chromium on the light exit surface of the light collecting portion such as the exit end of the optical fiber and gold plating.

  As the electrostatic latent image carrier, various shapes such as a drum type, a belt type, and a flat plate type (sheet type) can be used. The material for the electrostatic latent image bearing member may be any material as long as the surface is charged by irradiation with electrons or ions, so it does not have to be a photosensitive member, but an insulator such as anodized or a film such as polyethylene terephthalate (PET). A synthetic resin, glass or the like can also be used. If the electrostatic latent image carrier is a photosensitive member, it can be neutralized by irradiating light, and if it is an insulator, it can be neutralized by an AC voltage. In addition, when the electrostatic latent image carrier is an insulator, the deterioration is less likely to occur compared to the photoreceptor, and the long life is excellent.

The invention according to claim 2 is the image forming method according to claim 1, wherein the potential difference setting step uniformly charges the surface of the electrostatic latent image carrier on the dielectric layer side. It has the composition provided with.
In addition to the operation of the first aspect, this configuration has the following operation.
(1) Since the potential difference setting step includes a charging step for uniformly charging the surface of the electrostatic latent image carrier on the dielectric layer side, the voltage applied to the discharge electrode of the heat discharge type print head can be reduced. In particular, when a potential difference corresponding to the discharge control voltage can be formed only by the charging process, it is not necessary to apply a voltage directly by simply grounding the discharge electrode, greatly reducing damage to the discharge electrode. Thus, dielectric breakdown can be prevented, the durability of the discharge electrode can be improved, and deterioration in image quality over time can be prevented.

A third aspect of the present invention is the image forming method according to the first aspect, wherein the potential difference setting step is arranged so that the electrostatic latent image is disposed so as to face the heat-discharge type print head with the dielectric layer interposed therebetween. It has a configuration including a conductive layer side voltage selection step of applying a voltage to the conductive layer of the carrier or grounding.
With this configuration, in addition to the operation of the first aspect, the following operation is provided.
(1) Since the potential difference setting step includes a conductive layer side voltage selection step of applying a voltage or grounding to the conductive layer of the electrostatic latent image carrier disposed opposite to the heating / discharge type print head across the dielectric layer, The discharge electrode is grounded or applied with a voltage so as to form a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head. In the latent image forming step, the generation of discharge from the discharge electrode can be controlled only by selectively heating the discharge electrode with a heating means, and the handleability is excellent.

  Here, in the potential difference setting step, the discharge control voltage can be arbitrarily distributed and applied to the conductive layer of the electrostatic latent image carrier and the discharge electrode of the heat discharge type print head. Therefore, when one of the conductive layer of the electrostatic latent image carrier or the discharge electrode of the heat-discharge type print head is grounded, a discharge control voltage is applied to the other.

According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising: a heat discharge type print head having a discharge electrode and a heating means for selectively heating the discharge electrode; and a heat discharge type print head having a dielectric layer. An electrostatic latent image carrier on which an electrostatic latent image is formed on the surface of the dielectric layer by the action of electric charges of the discharge, the dielectric layer of the electrostatic latent image carrier, and the discharge electrode of the heating discharge type print head A potential difference setting unit that forms a potential difference corresponding to a discharge control voltage between the first and second electrostatic latent images formed on the surface of the electrostatic latent image carrier and developing the electrostatic latent image on the surface of the electrostatic latent image carrier. The image forming apparatus includes a visualization unit that forms a visible image and a transfer unit that transfers the visible image to a recording medium.
With this configuration, in addition to the operation of the third aspect, the following operation is provided.
(1) By forming a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heating and discharging type print head in the potential difference setting unit, it is possible to prepare for the discharge, Since the discharge can be generated simply by selectively heating the discharge electrode of the discharge type print head with the heating means, it is not necessary to control the high voltage, and the generation of the discharge can be easily controlled. It is possible to form an electrostatic latent image directly on the surface of the dielectric layer of the electrostatic latent image carrier by accurately irradiating ions to a desired position, and the image quality is excellent.
(2) The electrostatic latent image can be developed by the developing means to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier, and the visible image can be transferred to the printing medium by the transfer means. In addition to plain paper, various media such as an OHP sheet and glossy paper can be used as a print medium, and the versatility is excellent.
(3) Since an electrostatic latent image can be formed on the surface of the electrostatic latent image carrier by irradiating ions from the heat-discharge type print head, an exposure optical system such as a polygon mirror is not required, and the number of parts is reduced. Less structure can be simplified.

Here, the heat discharge type print head and the electrostatic latent image carrier are as described in the first aspect.
As the developing means, a developing device for performing toner development is preferably used, but development may be performed by ink or other methods. The toner used for toner development may be dry or wet.
As the transfer means, a transfer fixing roller in which the surface of a metal roller such as aluminum is covered with a synthetic rubber such as silicone rubber is preferably used. When a pressure fixing type toner is used during toner development, a visible image can be transferred to a recording medium and fixed by being pressed by a transfer unit.
The image forming apparatus preferably includes a cleaner that physically scrapes off the toner remaining on the surface of the latent electrostatic image bearing member after transfer. Thereby, the electrostatic latent image can be formed on the surface of the electrostatic latent image carrier in a stable state at all times, and the reliability is excellent.

A fifth aspect of the present invention is the image forming apparatus according to the fourth aspect, wherein the potential difference setting unit uniformly charges the surface of the electrostatic latent image carrier on the dielectric layer side. It has the structure provided with the part.
With this configuration, in addition to the operation of the fourth aspect, the following operation is provided.
(1) Since the potential difference setting unit has a charge control unit that uniformly charges the surface of the electrostatic latent image carrier on the dielectric layer side, the voltage applied to the discharge electrode can be kept low, or the discharge electrode can be grounded. Therefore, even when the discharge electrode of the heating and discharging type print head is heated by heating means using a heating resistor, the voltage between the heating resistor and the discharge electrode is high. It eliminates the need for insulation, simplifies the process of forming the insulating film, improves the yield of the heat-discharge type print head, and is superior in mass productivity and improves the heat transfer from the heating means to the discharge electrode. The occurrence of discharge can be quickly switched, and the printing speed is excellent.

Here, the charging control unit may be any unit that can uniformly charge the surface of the electrostatic latent image carrier on the dielectric layer side. For example, a non-contact discharge type corotron type or scorotron type charger, a contact type charging roller, a charging brush, or the like is preferably used.
The potential difference setting unit has a discharge electrode side voltage control unit that applies voltage to or grounds the discharge electrode of the heat discharge type print head. Insufficient voltage applied to form a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier uniformly charged by the charge controller and the discharge electrode of the heat-discharge type print head. Or for grounding.

A sixth aspect of the present invention is the image forming apparatus according to the fourth aspect, wherein the potential difference setting unit is arranged to face the heating / discharge type print head with the dielectric layer interposed therebetween. It has a configuration including a conductive layer side voltage selection unit that applies a voltage to the conductive layer of the carrier or grounds it.
With this configuration, in addition to the operation of the fourth aspect, the following operation is provided.
(1) The potential difference setting unit has a conductive layer side voltage selection unit that applies voltage to or grounds the conductive layer of the electrostatic latent image carrier disposed opposite to the heat discharge type print head with the dielectric layer interposed therebetween. The potential difference corresponding to the discharge control voltage can be formed by applying the required voltage or grounding according to the voltage (including grounding) applied to the discharge electrode of the heat discharge type print head. In addition, it is possible to form an electrostatic latent image by accurately irradiating a desired position on the surface of the electrostatic latent image carrier with ions generated in association with discharge, and the image quality is excellent.
(2) By applying a voltage to the conductive layer of the electrostatic latent image carrier at the conductive layer side voltage selector, the voltage applied to the discharge electrode can be kept low, or the voltage can be directly applied by simply grounding the discharge electrode. Therefore, even when heating the discharge electrode of a heat-discharge type print head by heating means using a heating resistor, high insulation is not required between the heating resistor and the discharge electrode, so The process of forming the film can be simplified to improve the yield of the heat-discharge type print head, and it is excellent in mass productivity, and also improves the heat transfer from the heating means to the discharge electrode, so that the occurrence of discharge can be confirmed. It can be switched quickly and has excellent printing speed.

  Here, the potential difference setting unit has a discharge electrode side voltage control unit that applies voltage to or grounds the discharge electrode of the heat discharge type print head. In order to form a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier that is applied with voltage or grounded to the conductive layer by the conductive layer side voltage selection unit and the discharge electrode of the heat discharge type print head. In addition, it is for applying insufficient voltage or grounding.

As described above, according to the image forming method and the image forming apparatus of the present invention, the following advantageous effects can be obtained.
According to invention of Claim 1, it has the following effects.
(1) In the potential difference setting step, a potential difference corresponding to the discharge control voltage is formed between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head, and image information is then transferred in the latent image forming step. Since the discharge can be generated by developing and selectively heating the discharge electrodes of the heat-discharge-type print head, it is not necessary to control the high voltage, and the generation of the discharge can be easily controlled. An image forming method excellent in controllability capable of forming a desired electrostatic latent image on the surface of the carrier can be provided.

According to invention of Claim 2, in addition to the effect of Claim 1, it has the following effects.
(1) In the charging step of the potential difference setting step, the voltage applied to the discharge electrode of the heat discharge type print head can be reduced by uniformly charging the surface of the electrostatic latent image carrier on the dielectric layer side in advance. In particular, when a potential difference corresponding to the discharge control voltage can be formed only by the charging process, it is not necessary to apply a voltage directly by simply grounding the discharge electrode, greatly reducing damage to the discharge electrode. Therefore, it is possible to provide an image forming method that can prevent dielectric breakdown, improve the durability of the discharge electrode, and prevent deterioration in image quality over time, and is excellent in image quality reliability.

According to invention of Claim 3, in addition to the effect of Claim 1, it has the following effects.
(1) In the conductive layer side voltage selection step of the potential difference setting step, by applying voltage or grounding to the conductive layer of the electrostatic latent image carrier disposed opposite to the heating / discharging print head with the dielectric layer interposed therebetween, A potential difference corresponding to the discharge control voltage can be reliably formed between the discharge electrode applied to the ground or voltage and prepared for the discharge. In the latent image forming step, the discharge electrode is selectively heated by the heating means. Thus, it is possible to provide an image forming method excellent in handleability capable of controlling the occurrence of discharge from the discharge electrode.

According to invention of Claim 4, it has the following effects.
(1) By forming a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heating and discharging type print head in the potential difference setting unit, it is possible to prepare for the discharge, Since the discharge can be generated simply by selectively heating the discharge electrode of the discharge type print head with the heating means, it is not necessary to control the high voltage, and the generation of the discharge can be easily controlled. To provide an image forming apparatus with excellent image quality capable of forming an electrostatic latent image directly on the surface of a dielectric layer of an electrostatic latent image carrier by accurately irradiating ions to a desired position. Can do.

According to invention of Claim 5, in addition to the effect of Claim 4, it has the following effects.
(1) By uniformly charging the surface of the electrostatic latent image carrier on the dielectric layer side with the charge control unit of the potential difference setting unit, the voltage applied to the discharge electrode of the heat discharge type print head can be kept low, By simply grounding the discharge electrode, no voltage can be applied directly, and even when the discharge electrode is heated by heating means using a heating resistor, high insulation is provided between the heating resistor and the discharge electrode. It is not necessary to simplify the process of forming the insulating film, improve the yield of the heat-discharge type print head, reduce the damage of the discharge electrode and prevent the occurrence of dielectric breakdown, and is excellent in mass productivity and handling, and heating It is possible to provide an image forming apparatus that is excellent in heat transfer from the means to the discharge electrode and that is capable of quickly switching whether or not discharge is generated, and that is excellent in printing speed.

According to invention of Claim 6, in addition to the effect of Claim 4, it has the following effects.
(1) The conductive layer side voltage selection unit of the potential difference setting unit faces the heating discharge type print head across the dielectric layer according to the voltage (including the case of grounding) applied to the discharge electrode of the heating discharge type print head. Applying or grounding the necessary voltage to the conductive layer of the arranged electrostatic latent image carrier can reliably form a potential difference corresponding to the discharge control voltage. It is possible to provide an image forming apparatus with high image quality that can form an electrostatic latent image by accurately irradiating a desired position on the surface of the electrostatic latent image carrier with a desired ion.
(2) By applying a voltage to the conductive layer of the electrostatic latent image carrier at the conductive layer side voltage selector, the voltage applied to the discharge electrode can be kept low, or the voltage can be directly applied by simply grounding the discharge electrode. Even when the discharge electrode of the heat-discharge type print head is heated by heating means using a heating resistor, there is no need for high insulation between the heating resistor and the discharge electrode, and the insulating film The yield of heat-discharge type print heads can be improved by simplifying the process of forming the electrode, and it is excellent in mass production and handling, as well as excellent heat transfer from the heating means to the discharge electrode, and whether or not discharge has occurred. It is possible to provide an image forming apparatus excellent in high-speed printing speed that can be switched quickly.

The image forming method and the image forming apparatus of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic front view of a main part of an image forming apparatus used in the image forming method according to the first embodiment.
In FIG. 1, 1 is an image forming apparatus used in the image forming method of Embodiment 1 of the present invention, 2 is a heating / discharging print head of the image forming apparatus 1, and 3 is a heating / discharging print head 2 having a dielectric layer 3a. The electrostatic latent image carrier of the image forming apparatus 1 in which an electrostatic latent image is formed on the surface of the dielectric layer 3a by the action of electric charges from the discharge from the electrostatic latent image carrier 4, the surface of the electrostatic latent image carrier 3 on the dielectric layer 3a side Charge control as a potential difference setting unit for forming a potential difference corresponding to a discharge control voltage between the dielectric layer 3a of the electrostatic latent image carrier 3 and the discharge electrode of the heating / discharge type print head 2 by uniformly charging And 5, a developing unit as a developing unit that develops the electrostatic latent image to form a visible image on the surface of the electrostatic latent image carrier 3 with the toner 35, and 6 represents the visible image on the print medium 30. A transfer fixing roller 7 as a transfer means for transferring to the surface 30a, 7 is the electrostatic latent image carrier 3 after transfer. Cleaner for cleaning taking physically scrapes the toner 35 remaining on the surface, 30 is plain paper, it is OHP sheet, various print media glossy paper.

In the present embodiment, the drum-type electrostatic latent image carrier 3 is used. However, the present invention is not limited to this, and various shapes such as a belt type and a flat plate type (sheet shape) may be used. it can.
The material of the electrostatic latent image carrier 3 may be any material as long as the surface is charged by irradiation with electrons or ions. An insulator such as alumite, a film-like synthetic resin such as polyethylene terephthalate (PET), glass, or the like. Can be used.
In addition, a non-contact discharge type corotron charger is used as the charge control unit 4, but the charge control unit 4 is not limited to this, and the charge control unit 4 is on the dielectric layer 3 a side of the electrostatic latent image carrier 3. Any material can be used as long as it can uniformly charge the surface.
As the developing means, the developing device 5 that performs toner development is used, but the toner may be dry or wet. Note that development may be performed by ink or other methods instead of toner.
As a transfer means, a transfer fixing roller 6 in which the surface of a metal roller such as aluminum was covered with a synthetic rubber such as silicone rubber was used. When a pressure fixing type toner is used during toner development, the visible image can be transferred to the printing medium 30 and fixed by being pressed by the transfer fixing roller 6.

Next, the heat discharge type print head of the image forming apparatus used in the image forming method of Embodiment 1 will be described.
2A is a schematic cross-sectional side view of a main part of the heat-discharge type print head in the image forming apparatus used in the image forming method of the first embodiment, and FIG. 2B is a diagram illustrating the image forming method of the first embodiment. It is a principal part schematic plan view of the discharge unit of the heating discharge type print head in the image forming apparatus to be used.
In FIG. 2, reference numeral 4 a denotes a discharge electrode side voltage control unit of the potential difference setting unit in the image forming apparatus 1 that is electrically connected to an electric connection unit 13 d of the heating and discharge type print head 2 to be described later and grounds the discharge electrode 13. A discharge unit of the discharge type print head 2, 11 is a substrate of a translucent discharge unit 10 formed of a synthetic resin such as polyimide, aramid, or polyetherimide, 11 a has an opening 11 b, and the substrate 11 is fixed. The shape-retaining plate of the discharge unit 10, 12 is a heat absorption layer of the discharge unit 10 formed by applying a black paint containing carbon or the like on the substrate 11 or vapor-depositing chromium, 13 is gold, A discharge electrode of the discharge unit 10 formed by depositing a metal such as silver, copper, or aluminum by vapor deposition, sputtering, printing, plating, etc., and then etching to form a ladder, 13a is a discharge current. 13 are a plurality of discharge generating portions, 13b is a common electrode of the discharge electrode 13 connecting both ends of the plurality of discharge generating portions 13a, and 13c is a discharge electrode 13 formed between the discharge generating portion 13a and the discharge generating portion 13a. A discharge opening 13d is connected to one end of the common electrode 13b of the discharge electrode 13 and is disposed on one side of the shape-retaining plate 11a and is grounded, and 15 is a discharge of the discharge unit 10. The heating means of the heating / discharge-type print head 2 includes a light irradiating portion that is disposed apart from the electrode 13 and selectively irradiates light to the discharge generating portion 13a of the discharge electrode 13.

The heat discharge type print head 2 scans the discharge electrode 13 of the discharge unit 10 with a laser beam (not shown) such as a polygon mirror or a galvanometer mirror that is emitted from the light irradiation unit of the heating unit 15. Arbitrary discharge generator 13a can be heated by serially scanning the heating means 15 itself with a heating means scanning section (not shown). Note that the laser beam may be condensed and irradiated by an optical fiber.
Any heating means 15 may be used as long as it can selectively heat the discharge generating portion 13a away from the discharge electrode 13. In addition to the device that emits laser light from the light irradiation portion, infrared rays are collected by an optical fiber or a condensing lens. What irradiates and irradiates can also be used.

The material of the substrate 3 is not limited to the present embodiment, the heat absorption layer 12 and the discharge electrode 13 can be formed on the surface, the heat resistance that can withstand the heating by the heating means 15, and the heating means 15. As long as it has heat transferability capable of transferring the heat propagated by the light emitted from to the discharge electrode 13. In addition, when the discharge electrode 13 has sufficient heat absorption property, the heat absorption layer 12 is not necessarily provided. Even if the arrangement of the substrate 11 and the heat absorption layer 12 is switched, the heat absorbed by the heat absorption layer 12 can be transmitted to the discharge electrode 13 through the substrate 11.
The discharge electrode 13 is formed in a ladder shape and divided into a plurality of discharge generation portions 13a, thereby increasing the discharge amount from the periphery of the discharge generation portion 13a and improving the discharge efficiency. Further, by providing the common electrode 13b in the vicinity of the discharge generating portion 13a, the cooling effect of the discharge generating portion 13a and the responsiveness to the heating stop are improved by increasing the heat radiation area of the discharge electrode 13 and increasing the heat capacity. Recording is possible. Furthermore, since a stable voltage can always be applied by reducing the resistance value, the discharge stability is also excellent.
Moreover, the shape of the discharge electrode 13 is not limited to this Embodiment, The number and arrangement | positioning of the discharge generation part 13a can be selected suitably. The discharge electrodes 13 can be arranged in a staggered pattern, a grid pattern, or the like, or the entire discharge electrode 13 can be formed in a single flat plate shape such as a rectangular shape or a square shape, or only one end side of the plurality of discharge generating portions 13a can be shared. The electrodes 13b may be connected to form a comb shape.

The image forming method of the first embodiment will be described based on the operation of the image forming apparatus configured as described above.
First, in the charging step of the potential difference setting step, the surface of the electrostatic latent image carrier 3 on the dielectric layer 3a side is uniformly negatively charged by the charging control unit 4.
Next, in the latent image forming step, the discharge generating portion 13a of the discharge electrode 13 of the heating and discharging type print head 2 is selectively heated by the heating means 15 based on the image information to generate a discharge, and the electrostatic latent image is carried. An electrostatic latent image is formed on the surface of the dielectric layer 3 a of the body 3. At this time, discharge control is performed between the dielectric layer 3 a of the electrostatic latent image carrier 3 and the discharge electrode 13 of the heating and discharging type print head 2. Discharge does not occur unless a potential difference corresponding to the voltage is formed.
In the present embodiment, the discharge electrode 13 of the heating / discharge type print head 2 is grounded by the discharge electrode side voltage control unit 4a of the potential difference setting unit, thereby the dielectric layer 3a of the electrostatic latent image carrier 3 uniformly charged and Although a potential difference corresponding to a discharge control voltage is formed between the discharge electrode 13 of the heat discharge type print head 2 and the charge amount on the electrostatic latent image carrier 3 side is insufficient, the discharge electrode side voltage What is necessary is just to apply a voltage to the discharge electrode 13 by the control part 4a.
In this embodiment, a case will be described in which an electrostatic latent image is formed by irradiating positive ions as a discharge is generated and neutralizing with negative charges.
Next, in the development process, the electrostatic latent image is developed by the developing device 5 to form a visible image, and then in the transfer process, the visible image is pressed by the transfer fixing roller 6 and applied to the surface 30 a of the print medium 30. Transferred and fixed.

The image forming method of Embodiment 1 has the following effects.
(1) In the potential difference setting step, a potential difference corresponding to a discharge control voltage is formed between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head, so that the latent image can be prepared. Since the discharge can be generated simply by selectively heating the discharge electrodes of the heat-discharge type print head based on the image information in the forming process, it is not necessary to control the high voltage, and the generation of the discharge can be controlled easily. An electrostatic latent image can be formed on the surface of the dielectric layer of the electrostatic latent image carrier.
(2) In the potential difference setting step, voltage is applied to the discharge electrode or grounded, or the dielectric layer is charged, so that there is a gap between the discharge electrode of the heat discharge type print head and the dielectric layer of the electrostatic latent image carrier. Can be set to be equal to the discharge control voltage, the potential difference can be easily adjusted, and the degree of freedom in setting the potential difference can be improved.
(3) The electrostatic latent image can be developed by the developing process to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier, and the visible image is transferred to the printing medium and recorded in the transferring process. In addition to plain paper, various media such as OHP sheets and glossy paper can be used as print media, and the versatility is excellent.
(4) Since the potential difference setting step includes a charging step for uniformly charging the surface of the electrostatic latent image carrier on the dielectric layer side, the voltage applied to the discharge electrode of the heat discharge type print head can be reduced. In particular, when a potential difference corresponding to the discharge control voltage can be formed only by the charging process, it is not necessary to apply a voltage directly by simply grounding the discharge electrode, greatly reducing damage to the discharge electrode. Thus, dielectric breakdown can be prevented, the durability of the discharge electrode can be improved, and deterioration of image quality over time can be prevented.

The image forming apparatus according to Embodiment 1 has the following effects.
(1) By forming a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heating and discharging type print head in the potential difference setting unit, it is possible to prepare for the discharge, Since the discharge can be generated simply by selectively heating the discharge electrode of the discharge type print head with the heating means, it is not necessary to control the high voltage, and the generation of the discharge can be easily controlled. It is possible to form an electrostatic latent image directly on the surface of the dielectric layer of the electrostatic latent image carrier by accurately irradiating ions to a desired position, and the image quality is excellent.
(2) The electrostatic latent image can be developed by the developing means to form a visible image on the surface of the dielectric layer of the electrostatic latent image carrier, and the visible image can be transferred to the printing medium by the transfer means. In addition to plain paper, various media such as an OHP sheet and glossy paper can be used as a print medium, and the versatility is excellent.
(3) Since an electrostatic latent image can be formed on the surface of the electrostatic latent image carrier by irradiating ions from the heat-discharge type print head, an exposure optical system such as a polygon mirror is not required, and the number of parts is reduced. Less structure can be simplified.
(4) Since the potential difference setting unit has a charge control unit that uniformly charges the surface of the electrostatic latent image carrier on the dielectric layer side, the voltage applied to the discharge electrode can be kept low, or the discharge electrode can be grounded. It is possible to prevent direct application of voltage, to prevent dielectric breakdown of the discharge electrode of the heat-discharge type print head, to improve the durability of the discharge electrode, and to improve the stability of discharge generation. .

(Embodiment 2)
FIG. 3 is a schematic front view of a main part of an image forming apparatus used in the image forming method according to the second embodiment. FIG. 4 is a main part of a heat discharge type print head in the image forming apparatus used in the image forming method according to the second embodiment. It is a schematic cross section side view. In addition, the same code | symbol is attached | subjected to the thing similar to Embodiment 1, and description is abbreviate | omitted.
In FIG. 3, the image forming apparatus 1A according to the second embodiment is different from the first embodiment in that the electrostatic latent image carrier 3A is electrically conductive with the dielectric layer 3a sandwiched between the heat-discharge type print head 2. The conductive layer 3b of the electrostatic latent image carrier 3 instead of the point having the layer 3b and the charge controller 4 that uniformly charges the surface of the electrostatic latent image carrier 3 on the dielectric layer 3a side as a potential difference setting unit. This is a point having a conductive layer side voltage selection section 4A for applying a voltage to the top.

The heating discharge type print head 2A used in the image forming apparatus 1A of the second embodiment is different from that of the first embodiment in that the discharge electrode 13A is formed in a flat plate shape and is separated from the discharge electrode 13. Instead of the heating means 15 having the arranged light irradiation part, a heating means 15A using a heating resistor 15a is provided.
In FIG. 4, 14 is an insulating film that insulates the discharge electrode 13A and the heating resistor 15a, and 15b is a driver IC of the heating means 15A that is electrically connected to the heating resistor 15a and controls the heat generation of the heating resistor 15a. is there.

The image forming method of the second embodiment will be described based on the operation of the image forming apparatus configured as described above.
The image forming method of the second embodiment is different from the first embodiment in that the surface of the electrostatic latent image carrier 3 on the dielectric layer 3a side is uniformly negatively charged directly by the charge controller 4 in the potential difference setting step. In place of the charging step of charging the electrostatic latent image carrier 3, a negative voltage is applied to the conductive layer 3b of the electrostatic latent image carrier 3 by the conductive layer side voltage selector 4A, so that the dielectric layer 3a side of the electrostatic latent image carrier 3 is It is a point which has the conductive layer side voltage selection process charged uniformly negatively.
Other steps are the same as those in the first embodiment, and thus the description thereof is omitted.

The image forming method according to the second embodiment has the following actions in addition to the actions (1) to (3) of the first embodiment.
(1) Since the potential difference setting step includes a conductive layer side voltage selection step of applying a voltage or grounding to the conductive layer of the electrostatic latent image carrier disposed opposite to the heating / discharge type print head across the dielectric layer, The discharge electrode is grounded or applied with a voltage so as to form a potential difference corresponding to the discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head. In the latent image forming step, the generation of discharge from the discharge electrode can be controlled only by selectively heating the discharge electrode with a heating means, and the handleability is excellent.

The image forming apparatus according to the second embodiment has the following actions in addition to the actions (1) to (3) of the first embodiment.
(1) The potential difference setting unit has a conductive layer side voltage selection unit that applies voltage to or grounds the conductive layer of the electrostatic latent image carrier disposed opposite to the heat discharge type print head with the dielectric layer interposed therebetween. The potential difference corresponding to the discharge control voltage can be formed by applying the required voltage or grounding according to the voltage (including grounding) applied to the discharge electrode of the heat discharge type print head. In addition, it is possible to form an electrostatic latent image by accurately irradiating a desired position on the surface of the electrostatic latent image carrier with ions generated in association with discharge, and the image quality is excellent.
(2) By applying a voltage to the conductive layer of the electrostatic latent image carrier at the conductive layer side voltage selector, the voltage applied to the discharge electrode can be kept low, or the voltage can be directly applied by simply grounding the discharge electrode. Therefore, even when heating the discharge electrode of a heat-discharge type print head by heating means using a heating resistor, high insulation is not required between the heating resistor and the discharge electrode, so The process of forming the film can be simplified to improve the yield of the heat-discharge type print head, and it is excellent in mass productivity, and also improves the heat transfer from the heating means to the discharge electrode, so that the occurrence of discharge can be confirmed. It can be switched quickly and has excellent printing speed.

  The present invention can greatly reduce the voltage applied to the discharge electrode or eliminate the need to apply a voltage to the discharge electrode, can be easily controlled, and can improve the durability and long life of the discharge electrode. Even when the discharge electrode is heated using a heating means such as an image forming method or a heating resistor, high insulation is not required between the heating means and the discharge electrode, and the process of forming an insulating film is simplified to yield. An image forming apparatus that is superior in mass production and long life, hardly changes over time in the amount of discharge from a heat-discharge type print head, and has excellent image quality reliability and stability. Thus, an electrostatic latent image can be formed directly on the electrostatic latent image carrier, and high-quality images can be formed on various printing media.

Schematic front view of main parts of an image forming apparatus used in the image forming method of Embodiment 1. (A) Schematic cross-sectional side view of a main part of the heat discharge type print head in the image forming apparatus used in the image forming method of Embodiment 1 (b) Heat discharge type printing in the image forming apparatus used in the image forming method of Embodiment 1 Schematic plan view of the main part of the head discharge unit Schematic front view of relevant parts of an image forming apparatus used in the image forming method of the second embodiment Schematic cross-sectional side view of a main part of a heat-discharge type print head in an image forming apparatus used in the image forming method of Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Image forming apparatus 2, 2A Heat discharge type print head 3, 3A Electrostatic latent image carrier 3a Dielectric layer 4 Charge control part 4a Discharge electrode side voltage control part 5 Developer 6 Transfer fixing roller 7 Cleaner 10 Discharge unit 11 Substrate 11a Shape holding plate 11b Opening 12 Heat absorption layer 13, 13A Discharge electrode 13a Discharge generating part 13b Common electrode 13c Discharge opening 13d Electrical connection part 14 Insulating film 15, 15A Heating means 15a Heating resistor 15b Driver IC
30 Printing medium 30a Surface 35 Toner

Claims (6)

A potential difference setting step for forming a potential difference corresponding to a discharge control voltage between the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heating discharge type print head; and image information about the discharge electrode of the heating discharge type print head. A latent image forming step of generating a discharge by selectively heating based on the electrostatic latent image carrier to form an electrostatic latent image on the surface of the dielectric layer of the electrostatic latent image carrier, developing the electrostatic latent image, and An image forming method comprising: a developing step of forming a visible image on the surface of the dielectric layer of an electrostatic latent image carrier; and a transferring step of transferring the visible image to a recording medium. The image forming method according to claim 1, wherein the potential difference setting step includes a charging step of uniformly charging a surface of the electrostatic latent image carrier on the dielectric layer side. The potential difference setting step includes a conductive layer side voltage selection step of applying a voltage to or grounding the conductive layer of the electrostatic latent image carrier disposed to face the heating / discharge type print head across the dielectric layer. The image forming method according to claim 1. A heat discharge type print head having a discharge electrode and a heating means for selectively heating the discharge electrode, and a dielectric layer, and static electricity is applied to the surface of the dielectric layer by the action of electric charges generated by the discharge from the heat discharge type print head. A potential difference corresponding to a discharge control voltage is formed between the electrostatic latent image carrier on which the electrostatic latent image is formed, and the dielectric layer of the electrostatic latent image carrier and the discharge electrode of the heat-discharge type print head. A potential difference setting unit; a visualization unit that develops the electrostatic latent image formed on the surface of the electrostatic latent image carrier to form a visible image on the surface of the electrostatic latent image carrier; An image forming apparatus comprising: transfer means for transferring a visual image to a recording medium. The image forming apparatus according to claim 4, wherein the potential difference setting unit includes a charge control unit that uniformly charges a surface of the electrostatic latent image carrier on the dielectric layer side. The potential difference setting unit includes a conductive layer side voltage selection unit that applies a voltage to or grounds the conductive layer of the electrostatic latent image carrier disposed opposite to the heating discharge type print head across the dielectric layer. The image forming apparatus according to claim 4.

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