JP3372188B2 - Ink charger, filter for ink charger, and print head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus such as a copying machine, a facsimile, a printer, etc., and more specifically, it intermittently ejects liquid ink or solid ink to selectively adhere or permeate a recording medium. The present invention relates to an ink charger, an ink charger filter, and a print head used in an image recording apparatus that forms an image by performing the above.

[0002]

2. Description of the Related Art In Japanese Patent Application No. 7-49778, we intermittently eject ink in accordance with an electric signal corresponding to image data to be recorded, and adhere or permeate it onto a recording medium to form the image. Proposed a new way to get.

The construction of this method is such that a heating device for heating ink for producing fine grain ink, an ejection device for ejecting the ink, and an electric signal corresponding to image data to be recorded are intermittently provided. The ejection device is configured to include a charging electrode unit that charges the ink and a back electrode unit that is disposed on the back surface of the recording medium and guides the charged ink onto the recording medium. The ejection control device includes a shutter unit that physically or electrically controls the ejection of the ink, and a control unit that outputs a control signal in response to the input of an electric signal corresponding to image data to control the shutter unit. The heating device, the charging electrode section, and the shutter section are integrated into a print head.

A description will be given below with reference to the drawings. FIG. 11 is an overall configuration diagram of a conventional print head. Inside the print head, a solid ink 41 is stored in the ink container 4 as an ink supply unit, and the fine particle ink 42 is supplied to the inside of the head (supply means is not shown). The charger 2 for charging the fine particle ink 42 is composed of a thin wire charging electrode 3 of 50 to 80 μm and a grid electrode 21.
The discharge part has a hole diameter according to the resolution, for example, 300 dp
In the case of i, the discharge hole 5 of about 120 to 300 μm is vacant, and the back electrode 7 is arranged outside the discharge hole 5.

As the color material of the ink, colored inks are used. For yellow, anthryothothiazole-based, quinophthalone-based, pyrazolonazo-based, pyridoneazo-based, styryl-based, etc. are used, and for magenta, anthraquinone-based, dicyanoimidazole-based, Thiadiazole azo type, tricyano vinyl type, etc. can be used, and cyan can use azo type, anthraquinone type, naphthoquinone type, indoaniline type and the like. Next, the operation will be described. The ink 41 becomes a fine particle ink 42 by a supply means (not shown).

By applying a voltage of +1 kV to 5 kV to the charging electrode 3, corona discharge occurs in the direction of the grid electrode 21 which is grounded, and the fine particle ink 42 is charged with positive ions.

The charged fine particle ink 42 is applied to the recording medium 6
-0.5 to-on the back electrode 7 arranged on the back side of the printing surface of
Induction on the recording medium by applying a negative voltage of 2 kV, for example, -1 kV. Here, the electric field shutter electrodes 51 and 52 are normally 50 kV to 1 kV depending on a control signal corresponding to an electric signal of image data to be recorded.
A voltage of (High level; H) or 0V (Low level; L) is applied.

For example, if the voltage of the electric field shutter electrode 51 is
500V (H), the voltage of the electric field shutter electrode 52 is 0V
In the case of (L), the ejection hole 5 is in a blocking state, and the finely charged fine particle ink 42 cannot pass through the ejection hole 5. On the other hand, when the voltage of both the electric field shutter electrodes 51 and 52 is 0 V (L), the fine particle ink 42 passes through the ejection holes 5 by being attracted to the electric field by the back electrode. In this case, the discharge hole 5 functions as an open state. In this way, ink ejection can be intermittently controlled by turning on / off the voltage of the electric field shutter electrode. Further, by controlling the potential of the electrode corresponding to each pixel, the passage of the fine particle ink 42 can be controlled in pixel units.

[0009]

In the above method, the finer the particle size of the ink, the higher the quality of the image that can be formed. Therefore, the solid ink is miniaturized by means such as a vaporization method and an ultrasonic method. Also,
As a means for charging fine ink particles, conventionally, there has been corona charging using a charging electrode such as a wire / needle electrode. However, the ink floating in the head at the time of charging adheres to the charging electrode, which causes problems such as a decrease in charging efficiency, abnormal discharge, and deterioration of the attached ink.

The present invention improves the charging efficiency by preventing ink from adhering to the charging electrode inside the charger.
An object of the present invention is to provide an ink charger that can suppress deterioration of ink.

Another object of the present invention is to provide a filter for an ink charger that allows air to flow through the inside of the charger but prevents the inflow of ink. Another object of the present invention is to provide a print head capable of reusing ink.

[0012]

Means for Solving the Problems] (claim 1) Ink charger filter of the present invention, have use a predetermined image by the ink was charged in an image recording apparatus for recording by electrostatic forces on a recording medium, wherein Ink charger is equipped with a charging electrode inside the housing to prevent ink from entering.
A filter used as a means to prevent
It is made of metal with pores, and the surface is insulated.
And is preferable from the viewpoint of improving discharge stability.
It

[0013]

(Claim 2 ) It is preferable that the filter is composed of a plurality of sheets from the viewpoint of enhancing the filter effect.

(Claim 3 ) In the filter, it is preferable that the fine pores have a diameter of 1 to 100 microns from the viewpoint of selecting the particle size of particles that prevent the fine particles from entering the charger. (Claim 4 ) The fine pores of the filter are preferably slits having a width of 1 to 100 μm from the viewpoint of suppressing clogging.

(Claim 5 ) In the filter, the fine pores of the plurality of filters are not aligned in the streamline direction of the air passing through the filters, thereby increasing the flow path resistance of the filters to the inside of the charger. It is preferable from the viewpoint of suppressing the intrusion of fine grain ink.

(Claim 6 ) It is preferable that the filter has a heat generating portion in order to prevent clogging when the ink used is solid ink. (Claim 7 ) It is preferable that the heat generating portion of the filter is formed of a planar heating element in order to make the surface temperature of the filter uniform.

(Claim 8 ) When the temperature T of the filter of the ink charger is the melting point Tm of the ink, Tm≤T≤T
It is preferable to control the temperature to be m + 40 ° C. from the viewpoint of not causing thermal damage to the ink.

(Claim 9 ) It is preferable from the viewpoint of energy saving that the temperature of the filter of the ink charger is controlled intermittently. (Claim 10 ) The print head of the present invention is provided with an ink feedback path to the ink supply unit.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a print head using the present invention. 1 is a filter, 2 is a charger, 3 is a wire type charging electrode, 4 is an ink container, 41 is ink, 42 is fine particle ink floating in the head, 5 is a discharge hole, 51 and 52 are electric field shutter electrodes, 6 Is a recording medium, 7 is a back electrode, 100 is the air flow direction in the front of the charger, 101 is the air flow direction in the rear of the charger, 102 is the ink flow direction from the ink supply unit, and 103 is the ink ejection direction. Is.

First, the principle of ink ejection will be described below. The ink 41 contained in the ink container 4 is supplied as fine-grained ink 42 inside the head. In the figure, the means for supplying the fine particle ink 42 from the ink container 4 to the inside of the head is not shown, but examples of the means include a supply method by heating and vaporization, and a method using ultrasonic vibration in combination. Regardless of the ink supply method, it is required to be a method that can supply all kinds of fine grain ink.

As the coloring material of the ink to be used, as an example of a colored ink, for yellow, an anthryothothiazole-based, quinophthalone-based, pyrazolonazo-based, pyridoneazo-based, styryl-based or the like is used, and for magenta, anthraquinone-based or dicyanoimidazole-based. , Cyanodiazole azo, and tricyanovinyl, and cyan can be azo, anthraquinone, naphthoquinone, indoaniline, and the like.

Next, the fine grain ink 42 inside the head is charged by the charger 2. The configuration of the charger 2 will be described in more detail with reference to FIG. The charger 2 has a grid electrode 21,
A case 22 and a filter unit 23 are provided as a case, a positive voltage of +1 to 5 kV is applied to the charging electrode 3, and the grid electrode 21 is electrically connected as a ground electrode. Further, the case 22 and the filter portion 23 are electrically insulated.

As a result, the wire type charging electrode 3 is discharged in the direction of the grid electrode 21 arranged on the front surface, and the ion wind passes through the grid to charge the fine particle ink 42 floating inside the head.

The charged fine particle ink 42 is discharged from the discharge hole 5 by applying a negative voltage of −0.5 to −2 kV, for example, −1 kV to the back electrode 7 in the vicinity of the discharge hole 5 shown in FIG. Fly to the outside of the head. At this time, the electric field shutter electrodes 51 and 52 are normally 50 kV to
1kV (High level; H) or 0V (Low level;
The voltage of L) is applied.

By controlling the flight of the fine grain ink 42 by applying an electric field to the electric field shutter electrodes 51 and 52, flight control becomes possible, and an image is formed on the recording medium 6 placed in front of the back electrode 7. .

The above is the overall configuration of the present invention, but in FIG. 1, even if the potentials applied to the respective electrodes are positive and negative, there is no problem with the ejection principle. Further, regarding the charger 2, the grid electrode 21 is described as a ground electrode, but it is not necessary to ground it as long as it has a potential difference with the wire-type charging electrode 3 that causes corona discharge.

Here, in the charger 2, the air flows in the directions indicated by 100 and 101, and the fine particle ink 42 floating in the head also moves along with this flow. However, since the filter 1 is provided, the floating fine particle ink 42 cannot enter the inside of the charger 2. Therefore, ink does not adhere to the wire type charging electrode 3, and the corona discharge is continued extremely stably.

Here, regarding the shape of the charging electrode, the wire type charging electrode 3 is shown in the figure, but a shape in which electric charge is concentrated because corona discharge is easily generated, for example, a needle electrode or a sawtooth electrode may be used. .

FIG. 3 shows an embodiment of the invention according to claim 3 and shows the structure of a filter. The center is
The metal plate filter portion, on which the fine holes are formed by a fine processing means such as laser processing or etching processing, and the outer side 1a are made of an insulating material such as polyimide or fluororesin as an example. Thereby, the stability of the discharge of the wire type charging electrode 3 is improved, and the corona wind can be stably flown in a desired direction.

FIG. 4 shows an embodiment of the invention according to claim 4, wherein a plurality of filters 1 are installed to enhance the filter effect. FIG. 5 shows an embodiment of the invention according to claim 5, and is an enlarged perspective view of the filter when the pore diameter of the filter 1 is 1 μm. This makes it possible to select the particle size of particles that prevent the particles from entering the charger 2.

FIG. 6 shows an embodiment of the invention according to claim 6 and is an enlarged perspective view of the filter when the slit width of the filter 1 is 10 μm. As a result, it is possible to select the particle size of the particles that prevent the particles from entering the charger 2 and suppress clogging.

FIG. 7 shows an embodiment of the invention according to claim 7, and is a filter enlarged perspective view showing a state in which the fine holes of the plurality of filters are not aligned in the streamline direction of the air passing through the filter 1. is there. As a result, the flow path resistance of the filter 1 is increased, and it is possible to prevent the fine particle ink from entering the inside of the charger. Although FIG. 7 shows a layout of three filters, the number of filters used is not limited to this.
In addition, although a filter having a circular hole shape is described in FIG. 7, as for a filter to which a slit is applied, the slit pattern may be rotated or translated,
By laying out, it is easy to create an unaligned state.

FIG. 8 shows an embodiment of the present invention according to claim 8. By adding a heater 1b as a heat generating portion to the filter, the effect of preventing clogging when the ink used is solid ink is obtained. To be Although FIG. 8 describes a filter having a circular hole shape, the same applies to a filter to which a slit is applied. Further, it goes without saying that a method of heating by externally connecting the filter with a heat source may be considered.

FIG. 9 shows an embodiment of the invention according to claim 9 in which a planar heating element is incorporated in a filter, and a heating resistor 1c such as a metal film is used as an example of a photolithography process, a screen printing process or the like. It was formed by. As a result, the surface temperature of the filter is made uniform, a local high temperature state does not occur, and damage to the ink can be minimized even when using ink or the like that is significantly deteriorated by heat.

The heat generating filter shown in FIGS. 8 and 9 is effective when the ink 41 is solid as described above, and the control temperature T is within the range of Tm when the melting point of the solid ink is Tm. Within the range of ≦ T ≦ Tm + 40 ° C., no deterioration of the ink color material was observed within the actual use time. In addition, these temperature controls do not always have to be continued during operation, and should be performed according to the usage situation and device configuration. For example, the temperature control should be performed within 10 to 60 minutes during use.
It may be performed intermittently and regularly, such as once.

FIG. 10 shows an embodiment of the invention according to claim 12, 1'is the filter with heat generating unit 1'shown in FIGS. 8 and 9, 8 is an ink tray, and 9 is an ink supply unit. Shows the recovery route to. As a result, the fine-grained ink collected by the filter is collected in the ink tray 8 during the operation of the heat generating part and returned to the ink supply part through the recovery path 9.
Therefore, the ink can be reused and the efficiency of use of the ink can be improved.

[0038]

In the ink charging device for filter <br/> of claim 1, wherein, according to the present invention, in the ink charger ink does not adhere to the charging electrode for the inflow is not the charger inside the ink,
On construction is simple, it is easy to control the creation and air inflow filter, Ri Do and thin filters, deer
Also makes it easier to control the direction of the corona wind of the charger, and
Higher efficiency can be expected, and the print time is short.
Reduction in power consumption can be achieved.

[0039]

In the filter for the ink charger according to the second aspect of the present invention, by providing a plurality of filters, the effect of preventing the invasion of the ink is further enhanced, and the ink adheres to the charging electrode even after a long time driving. do not do.

In the ink charger filter according to a third aspect of the present invention, the pore diameter is set to 1 to 100 μm, which has the effect of preventing the fine particle ink to be used from flowing into the inside of the charger when the particle size is 1 to 100 μm. .

In the ink charger filter of the fourth aspect , since the hole shape is a slit shape, it is effective against clogging. In the ink charger filter according to the fifth aspect, the flow path resistance passing through the filter is increased, so that the effect of preventing ink from entering the charger is enhanced.

In the ink charger filter according to the sixth aspect, the ink attached to the filter can be collected in a liquid state by the heat generated from the heat generating portion, so that the filter refreshing effect and the ink reuse can be achieved.

In the ink charger filter according to the seventh aspect of the present invention, by providing the sheet heating element, a thin filter can be constructed, and the temperature distribution in the filter can be made uniform, thereby damaging the reused ink. Few.

In the filter for the ink charger according to the eighth aspect , by setting the filter temperature T to Tm ≦ T ≦ Tm + 40 ° C., thermal damage to the ink can be suppressed, and the number of reuses of the ink is increased. To do.

In the ink charger filter according to the ninth aspect , the energy saving effect can be expected by performing the control intermittently. In the print head according to the tenth aspect, the ink attached to the filter can be collected in the supply unit, and the ink attached to the filter can be reused.

[Brief description of drawings]

FIG. 1 is an overall conceptual diagram showing a print head using an ink charger according to the present invention.

FIG. 2 is a sectional view showing an embodiment of an ink charger according to the present invention.

FIG. 3 is a sectional view showing an embodiment of a filter for an ink charger according to the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the ink charger filter according to the present invention.

FIG. 5 is a perspective view showing another embodiment of the ink charger filter according to the present invention.

FIG. 6 is a perspective view showing another embodiment of the ink charger filter according to the present invention.

FIG. 7 is a perspective view showing another embodiment of the ink charger filter according to the present invention.

FIG. 8 is a perspective view showing another embodiment of the ink charger filter according to the present invention.

FIG. 9 is a perspective view showing another embodiment of the ink charger filter according to the present invention.

FIG. 10 is an overall schematic diagram showing an embodiment of a print head according to the present invention.

FIG. 11 is an overall schematic diagram showing a print head as a prior art.

[Explanation of symbols]

1 filter 1a Insulator for filter 1b Filter heater 1c Sheet heating element 2 charger 21 grid electrode 22 cases 3 charging electrodes 4 ink containers 41 ink 42 Fine-grained ink that floats inside the head 5 discharge holes 51, 52 Electric field shutter electrode 6 recording media 7 Back electrode 8 Ink collection container 9 collection routes 100 Corona-like movement direction 101 Direction of the wind that flows into the charger 102 Supply direction of fine grain ink 103 Fine particle ink flight direction

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-91863 (JP, A) JP-A-8-238784 (JP, A) JP-A-7-137297 (JP, A) Actual development Sho-61- 71438 (JP, U) Actual development Sho 58-28851 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2/06 B41J 2/175 B41J 2/385

Claims (10)

(57) [Claims] 1. An image recording apparatus for recording a predetermined image of charged ink on a recording medium by electrostatic force.
There, the ink Lee ink charging device arranged charging electrode in a housing which is adapted difficult to penetrate, a filter used as a way ink is hard to penetrate, a metal having micropores It is, features and be Louis ink charging dexterity filter that insulation treatment is applied to the surface portion. 2. A plurality of sheets are formed.
1. The ink charger filter according to 1. 3. A process according to claim 1 or 2 ink charging dexterity filter, wherein the diameter of the micropores is 100 microns 1. Wherein said micropores claim 1 or, characterized in that the width of slit 100 microns 1
2. The ink charger filter described in 2 . 5. The ink charger filter according to claim 2, wherein the fine holes of the plurality of filters are not aligned in a streamline direction of air passing through the filters. 6. A heat generating portion is provided.
The filter for an ink charger according to any one of 1 to 5 . 7. The filter for an ink charger according to claim 6 , wherein the heat generating portion is formed of a planar heat generating element. 8. The temperature control of a filter used as a means for preventing ink from penetrating is controlled so as to show Tm ≦ T ≦ Tm + 40 ° C. when a melting point Tm of the ink is set. 1. The ink charger according to 1. 9. The ink charger according to claim 8, wherein the temperature of the filter is controlled intermittently. 10. A print head comprising the ink charger according to claim 8 or 9 , wherein an ink feedback path to an ink supply unit is installed.