Printer, ink, and method of controlling charge of liquid-contact member

Abstract

To provide a technique capable of preventing pigment particles from adhering to a liquid contact member and preventing aggregation and precipitation.SOLUTION: A printer 30 includes an ink head 31 configured to eject an ink 20 containing pigment particles 22, and a liquid-contact member 40 configured to supply the ink 20 to the ink head 31 and to be in contact with the ink 20, wherein the liquid-contact member 40 is made of a material that is easily charged to the same polarity as the pigment particles 22, and the pigment particles 22 and the liquid-contact member 40 are charged to the same polarity.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a printer and a technique for controlling the charge of ink and liquid-contacting members. [Background technology]

[0002] Inkjet printers are required to have smooth ink flow. One known technique for achieving smooth ink flow is disclosed in Patent Document 1, for example.

[0003] In the inkjet recording device disclosed in Patent Document 1, a first conductive flow path member and a second conductive flow path member are interposed in the flow path through which the ink flows. An alternating current is applied to the first conductive flow path member and the second conductive flow path member. This application causes the pigment particles to vibrate (Patent Document 1, paragraph 0010). This vibration has the advantage of preventing the pigment particles from adhering to the wall of the flow path and from agglomerating and settling.

[0004] However, there is a drawback in that the materials that can be used for the flow path member are limited to conductive flow path members, which narrows the options for materials that can be used for the flow path member.

[0005] Furthermore, the technology of Patent Document 1 uses a voltage of 5V AC. If the voltage exceeds 5V, it will have an unwanted effect on the piezoelectric element. In addition, the technology of Patent Document 1 uses a frequency of 50Hz. If the voltage exceeds 50Hz, the entire ink will vibrate, which may result in unnecessary ink being ejected from the nozzle (Patent Document 1, paragraph 0042).

[0006] That is, with the technology of Patent Document 1, there is a risk that the effects of vibrations will affect surrounding components or induce ink leakage from the nozzles. As printers are required to have longer life spans, there is a need for technologies that can replace vibration. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-229997 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a technology that can prevent pigment particles from adhering to the wall of the liquid-contacting member and prevent aggregation and precipitation, and that can replace vibration. [Means for solving the problem]

[0009] According to the invention of claim 1, an ink head that ejects ink containing pigment particles; a liquid contact member that is a member for supplying the ink to the ink head and that comes into contact with the ink, the liquid contact member is made of a material that is easily charged to the same polarity as the pigment particles, A printer is provided in which the pigment particles and the liquid-contacting member are charged to the same polarity. [Effects of the Invention]

[0010] In the invention according to claim 1, the pigment particles and the liquid contact member are charged with the same polarity, so a repulsive force acts between the liquid contact member and the pigment particles. This repulsive force prevents the pigment particles from adhering to the wall of the liquid contact member. In addition, a repulsive force acts between the pigment particles themselves, and this repulsive force maintains the dispersibility of the pigment particles. That is, even when a material having electrostatic properties is used, the dispersibility of the pigment particles can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1(a) is a diagram illustrating the principle of the pigment particle charging mechanism used in the present invention, and FIG. 1(b) is an enlarged view of part b in FIG. 1(a) and also illustrates the mechanism. [Figure 2] 1A is a diagram showing the basic configuration of a printer according to the present invention, FIG. 1B is a cross-sectional view taken along line bb of FIG. 1A and is also a functional diagram, and FIG. 1C is a cross-sectional view taken along line cc of FIG. 1A and is also a functional diagram. [Figure 3] This is a triboelectric series table that explains materials that are more likely to be negatively charged than titanium oxide. [Figure 4] 1A is a diagram showing the principle of a pigment particle charging mechanism used in a modified example of the present invention, and FIG. 1B is an enlarged view of part b in FIG. 1A and also shows the mechanism. [Figure 5] 1A is a diagram showing the basic configuration of a printer according to a modified example of the present invention, FIG. 1B is a cross-sectional view and functional diagram along line bb in FIG. 1A, and FIG. 1C is a cross-sectional view and functional diagram along line cc in FIG. [Figure 6] This is a triboelectric table that explains materials that are more likely to be positively charged than aluminum. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0013] [Charge control of ink and wetted parts] The charge control of the ink and the liquid-contacting member according to the present invention is carried out by a pigment particle charging step carried out using a pigment particle charging mechanism and a liquid-contacting member charging step carried out using a liquid-contacting member charging mechanism. The pigment particle charging mechanism and the liquid contact member charging mechanism will be described below in order.

[0014] [Pigment particle charging mechanism] Please refer to Figure 1(a). The pigment particle charging mechanism 10 includes a first DC high-voltage power supply 11, a first conducting wire 12 extending from the first DC high-voltage power supply 11, and a cylindrical charging electrode 13 connected to the tip of the first conducting wire 12.

[0015] The cylindrical charging electrode 13 having this configuration is provided, for example, midway through or at the outlet of a liquid injection nozzle 16 extending from an ink tank 15 corresponding to a stock solution tank. The liquid injection nozzle 16 is set in the ink cartridge (including the ink bottle) 41, and a predetermined amount of ink is injected into the ink cartridge 41 by opening and closing the valve 17.

[0016] [ink] See Figure 1(b). The ink 20 is made by adding pigment particles 22 and other additives to a solution 21. If the ink 20 is a white ink, the pigment particles 22 are, for example, titanium oxide 23. Titanium oxide 23 has the property of being easily negatively charged.

[0017] Therefore, in FIG. 1( a ), a cylindrical charging electrode 13 is negatively charged by a first DC high voltage power supply 11 . 1(b), the titanium oxide 23 is negatively charged by the cylindrical charging electrode 13 and is injected into the ink cartridge 41 in this state.

[0018] [Printer] Please refer to Figure 2(a). The printer 30 comprises an ink head 31 that ejects ink, a liquid contact member 40 that supplies ink to the ink head 31 and comes into contact with the ink, and a liquid contact member charging mechanism 50 that charges part or all of the liquid contact member 40 with a desired polarity.

[0019] [Wetted parts] The liquid contact member 40 is a member that comes into contact with ink, and is composed of, for example, an ink cartridge 41, an ink flow path 42 extending from the ink cartridge 41, a sub-tank 43 that is provided midway along the ink flow path 42 and stores ink, and a damper 44 that is attached to the ink head 31 and stores ink. This is just an example, and the sub-tank 43 may be omitted.

[0020] The ink cartridge 41 is configured to be detachable from the printer 30. The ink cartridge 41 may have an ink pouch therein that hermetically stores ink (in this case, the ink pouch serves as the liquid contact member 40). The ink may be stored directly in the body of the ink cartridge 41. The shape of the ink cartridge 41 is not limited, and it may be a bottle type (ink bottle). The ink flow path 42 is configured, for example, by an ink tube. The damper 44 adjusts the pressure of the ink supplied to the ink head 31. The ink stored in the ink cartridge 41 is supplied to the ink head 31 via the ink flow path 42, sub-tank 43, and damper 44.

[0021] [Wetted material charging mechanism] The liquid-contacting member charging mechanism 50 includes, for example, a second DC high-voltage power supply 51, a second conducting wire 52 extending from the second DC high-voltage power supply 51, and a bar-shaped charging electrode 53 connected to the tip of the second conducting wire 52. The bar-shaped charging electrode 53 may be a so-called gun-type charging electrode. The liquid-contacting member charging mechanism 50 may also be a charging mechanism that utilizes a corona discharge phenomenon.

[0022] [Arrangement of bar-shaped charged electrodes] The bar-shaped charging electrode 53 is attached to, for example, the ink cartridge 41. Alternatively, the bar-shaped charging electrode 53 is attached to the ink flow path 42. Alternatively, the bar-shaped charging electrode 53 is attached to the ink cartridge 41, the ink flow path 42, the sub-tank 43, and the damper 44. Therefore, the bar-shaped charging electrode 53 can be attached to all or part of the liquid contact member 40 as desired.

[0023] [Dispersibility of pigment particles] Please refer to Figure 2(b). Ink 20 is filled in an ink cartridge 41. This ink 20 contains pigment particles 22 of titanium oxide 23 in a solution 21. The titanium oxide 23 is negatively charged in advance. Since both the pigment particle 22 and the neighboring pigment particle 22 are negatively charged, a first repulsive force F1 is generated between the pigment particles 22. This first repulsive force F1 causes the pigment particles 22 to move away from each other. As a result, the pigment particles 22 are dispersed. Because they are dispersed, aggregation and sedimentation do not occur.

[0024] [Effect of bar-shaped charged electrodes] The bar-shaped charging electrode 53 irradiates the ink cartridge 41 with negative ions, resulting in the ink cartridge 41 being negatively charged. Because both the ink cartridge 41 and the pigment particles 22 are negatively charged, a second repulsive force F2 is generated between the ink cartridge 41 and the pigment particles 22. This second repulsive force F2 causes the pigment particles 22 to move away from the ink cartridge 41. As a result, the pigment particles 22 are prevented from adhering to the ink cartridge 41.

[0025] As shown in FIG. 2(c), for example, the walls of the ink flow path 42 may be negatively charged. Because the walls of the ink flow path 42 and the pigment particles 22 are both negatively charged, a second repulsive force F2 is generated between the walls of the ink flow path 42 and the pigment particles 22. This second repulsive force F2 causes the pigment particles 22 to move away from the walls of the ink flow path 42. As a result, the pigment particles 22 are prevented from adhering to the walls of the ink flow path 42.

[0026] [Strengthening the second repulsion] Focusing on the second repulsive force F2, the larger the second repulsive force F2, the better the pigment particles 22 are separated from the walls of the ink cartridge 41 and the ink flow path 42. Therefore, strengthening the second repulsive force F2 is considered. Please refer to Figure 3. Figure 3 shows the well-known triboelectric series. Titanium oxide is in the region where it tends to be negatively charged.

[0027] [Wetted material] It is recommended that the material of the liquid contact member 40 be selected from rubber, polystyrene, polyurethane, polyester, axle, polypropylene, polyethylene, cellophane, polyvinyl chloride, Teflon (registered trademark), silicone, and fluororesin. These materials are more likely to be negatively charged than titanium oxide (these materials are located to the right of titanium oxide in the triboelectric column of FIG. 3). By selecting a material that is more likely to be charged than the pigment particles 22 as the material for the liquid contact member 40, the second repulsive force F2 can be made stronger.

[0028] An example in which the present invention is applied to white ink has been described above. In recent years, metallic ink has also come into practical use, and therefore, an example in which the present invention is applied to metallic ink will be described below as a modified example.

[0029] [Pigment particle charging mechanism (changed example)] Please refer to Figure 4(a). The pigment particle charging mechanism 10 according to the modified example has the same configuration as the pigment particle charging mechanism 10 described with reference to FIG. 1(a), and therefore the same reference numerals will be used and detailed description will be omitted.

[0030] [Ink (changed example)] See Figure 4(b). If the ink 20 is a metallic ink, the pigment particles 22 are, for example, aluminum 25. Aluminum 25 has the property of being easily positively charged.

[0031] Therefore, in FIG. 4( a ), the cylindrical charging electrode 13 is positively charged by the first DC high voltage power supply 11 . Then, in FIG. 4(b), the aluminum 25 is positively charged and is injected into the ink cartridge 41 in this state.

[0032] [Printer (changed example)] Please refer to Figure 5(a). The printer 30 has the same configuration as the printer 30 described in FIG. 2(a), so the same reference numerals will be used and detailed description will be omitted.

[0033] [Dispersibility of pigment particles (changed example)] See Figure 5(b). Ink 20 is filled in an ink cartridge 41. This ink 20 contains pigment particles 22 of aluminum 25 in a solution 21. The aluminum 25 is positively charged. Since both the pigment particle 22 and adjacent pigment particles 22 are positively charged, a first repulsive force F1 is generated between the pigment particles 22. This first repulsive force F1 causes the pigment particles 22 to move away from each other. As a result, the pigment particles 22 are dispersed. Because they are dispersed, no aggregation or sedimentation occurs.

[0034] [Function of bar-type charged electrodes (modified example)] The bar-shaped charging electrode 53 irradiates the ink cartridge 41 with positive ions, resulting in the ink cartridge 41 being positively charged. Because both the ink cartridge 41 and the pigment particles 22 are positively charged, a second repulsive force F2 is generated between the ink cartridge 41 and the pigment particles 22. This second repulsive force F2 causes the pigment particles 22 to move away from the ink cartridge 41. As a result, the pigment particles 22 are prevented from adhering to the ink cartridge 41. As shown in FIG. 5(c), for example, the walls of the ink flow path 42 may be positively charged.

[0035] [Secondary repulsion strengthening (change example)] Please refer to Figure 6. Figure 6 shows the well-known triboelectric potential chart. Aluminum is in the region where it tends to be positively charged.

[0036] [Wetted material (example of change)] It is recommended that the material of the liquid contact member 40 be selected from acetate, zinc, lead, rayon, nylon (registered trademark), and glass. These materials are more likely to be positively charged than aluminum (these materials are located to the left of aluminum in the triboelectric column of FIG. 6). By selecting a material that is more likely to be positively charged than the pigment particles 22 as the material of the liquid contact member 40, the second repulsive force F2 can be made stronger.

[0037] Based on the above-described matters, the present invention can be summarized as follows. As shown in Figures 2(a) and 2(b), the present invention provides: an ink head 31 that ejects ink 20 containing pigment particles 22; a liquid contact member (40) that is a member for supplying the ink (20) to the ink head (31) and that comes into contact with the ink (20); The liquid contact member 40 is made of a material that is easily charged to the same polarity as the pigment particles 22, The pigment particles 22 and the liquid contact member 40 are charged to the same polarity, thereby providing a printer 30.

[0038] In the present invention, the pigment particles 22 and the liquid contact member 40 are charged with the same polarity, so that the second repulsive force F2 acts on the pigment particles 22. This second repulsive force F2 causes the pigment particles 22 to move away from the liquid contact member 40, as shown in FIG. 2(c) and FIG. 5(c), preventing the pigment particles 22 from adhering to the wall of the liquid contact member 40.

[0039] Furthermore, as shown in FIG. 2(b) and FIG. 5(b), a first repulsive force F1 acts between the pigment particles 22, and the dispersibility of the pigment particles 22 is maintained. That is, even when a material having electrostatic properties is used, the dispersibility of the pigment particles 22 can be improved.

[0040] Additionally, in the present invention, the liquid contact member 40 is made of a material that is easily charged to the same polarity as the pigment particles 22. The material that is easily charged is not limited to a conductive material. Therefore, the present invention has the advantage of widening the options for materials that can be used for the liquid contact member 40.

[0041] The printer 30 does not include the pigment particle charging mechanism 10 described in Figure 1 (or Figure 4) as a component. However, the pigment particle charging mechanism 10 may be included as a component of the printer 30.

[0042] Preferably, as shown in FIG. 3 (or FIG. 6), the liquid contact member 40 is made of a material that is more easily charged than the pigment particles 22 (titanium oxide 23 or aluminum 25).

[0043] A repulsive force (second repulsive force F2) can be generated between the pigment particles 22 and the liquid contact member 40.

[0044] Furthermore, according to the present invention, there is provided a pigment particle charging step of charging the pigment particles 22 contained in the ink 20; a liquid contact member charging step of charging a liquid contact member 40 that comes into contact with the ink 20; Including, The liquid contact member 40 is made of a material that is easily charged to the same polarity as the pigment particles 22, In the pigment particle charging step and the liquid contact member charging step, the pigment particles 22 and the liquid contact member are charged to the same polarity, thereby providing a charge control method for the ink and the liquid contact member.

[0045] Even when a material having electrostatic properties is used, the dispersibility of the pigment particles can be improved.

[0046] While the printer 30 has been described above, the present invention may also be an ink container (ink cartridge 41, ink bottle, ink pouch, etc.) that stores ink containing pigment particles, and in which at least the portion of the ink container that comes into contact with the ink is made of a material that is easily charged to the same polarity as the pigment particles, and the pigment particles and the liquid-contacting member are charged to the same polarity. It is preferable that at least the portion of the ink container that comes into contact with the ink is made of a material that is more easily charged than the pigment particles 22. [Industrial Applicability]

[0047] The present invention is suitable for inkjet printers. [Explanation of symbols]

[0048] 10...pigment particle charging mechanism, 20…ink, 22...pigment particles, 30...printer, 31...ink head, 40...liquid-contacting member, 50...liquid contact member charging mechanism, F1…first repulsive force, F2…Second repulsive force.

Claims

1. an ink head that ejects ink containing pigment particles; a liquid contact member that is a member for supplying the ink to the ink head and that comes into contact with the ink, the liquid contact member is made of a material that is easily charged to the same polarity as the pigment particles, the pigment particles and the liquid contact member are charged to the same polarity; Printer.

2. 2. The printer according to claim 1, wherein the liquid contact member is made of a material that is more easily charged than the pigment particles.

3. a pigment particle charging step of charging pigment particles contained in the ink; a liquid contact member charging step of charging a liquid contact member that comes into contact with the ink; Including, the liquid contact member is made of a material that is easily charged to the same polarity as the pigment particles, In the pigment particle charging step and the liquid contact member charging step, the pigment particles and the liquid contact member are charged to the same polarity.

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