Method and apparatus for cleaning inkjet print heads
The method uses a two-step cleaning process with compatible and incompatible solvents to clean inkjet heads, effectively removing foreign substances and preventing aggregate formation, ensuring stable ink ejection.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KONICA MINOLTA INC
- Filing Date
- 2022-06-30
- Publication Date
- 2026-06-02
AI Technical Summary
Existing inkjet head cleaning methods disrupt the dispersion state of ink using solvents different from the ink, leading to pigment aggregation and ejection abnormalities.
A method involving a first cleaning solution that maintains ink dispersion, followed by a second cleaning solution with a different solvent, and optional steps of ink discharge and solution removal, using cleaning units like web, roller, or nozzle types to clean the inkjet head.
Effectively removes foreign substances while suppressing aggregate formation, maintaining ink stability and preventing ejection abnormalities.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for cleaning an inkjet head and a cleaning device for cleaning the inkjet head.
Background Art
[0002] In an inkjet head, it is known that ink ejection becomes unstable due to thickening of the ink, aggregation of pigments, or precipitation of components in the ink in the ink flow path toward the ejection port.
[0003] In Japanese Patent Application Laid-Open No. 2010-260296 (Patent Document 1), in order to simultaneously perform thickening or aggregation of ink and removal of water-soluble precipitates (foreign substances), an organic solvent solution containing water is used as a cleaning liquid to clean the inkjet head.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the cleaning method for cleaning an inkjet head using the cleaning liquid described in Patent Document 1, since a solvent different from the solvent contained in the ink penetrates into the inkjet head, the dispersion state of the ink is disrupted and the pigment aggregates. The generated pigment aggregates grow under the action of forces such as shear force when passing through the flow path, and as a result, ejection abnormalities may occur.
[0006] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a method for cleaning an inkjet head and a cleaning device capable of removing foreign substances while suppressing the generation of aggregates. [Means for solving the problem]
[0007] In the inkjet head cleaning method according to this disclosure, the inkjet head is cleaned using a first cleaning solution capable of maintaining the dispersion state of the ink and a second cleaning solution having a solvent different from the ink.
[0008] In the method for cleaning an inkjet head based on the above disclosure, the first cleaning solution may be composed of the same solvent as the ink.
[0009] The method for cleaning an inkjet head according to the present disclosure may include the steps of supplying the first cleaning solution to the ejection surface of the inkjet head, and, after the step of supplying the first cleaning solution to the ejection surface, supplying the second cleaning solution to the ejection surface.
[0010] The method for cleaning an inkjet head according to the above disclosure may further include a step of discharging the ink from the inkjet head after the step of supplying the second cleaning solution to the discharge surface.
[0011] The method for cleaning an inkjet head according to the above disclosure includes a step of supplying the second cleaning solution to the ejection surface, followed by a step of removing the first cleaning solution and / or the second cleaning solution remaining on the ejection surface. Furthermore It's a good idea to be prepared.
[0012] In the inkjet head cleaning method according to the above disclosure, the ink may contain wax. In this case, the inkjet head cleaning method may further include a step of gelling the ink located at least inside the ejection port of the inkjet head before the step of supplying the first cleaning solution to the ejection surface.
[0013] In the inkjet head cleaning method based on the above disclosure, ultraviolet-curable ink may be used as the ink. In this case, it is preferable to use water as the second cleaning solution.
[0014] The cleaning apparatus according to this disclosure is a cleaning apparatus for cleaning an inkjet head. The cleaning apparatus includes a cleaning unit for cleaning the ejection surface of the inkjet head using a first cleaning solution capable of maintaining the dispersion state of the ink and a second cleaning solution having a solvent different from the ink.
[0015] In the cleaning apparatus based on the above disclosure, the cleaning unit may include a web that moves while in contact with the ejection surface of the inkjet head, a first supply unit that supplies the first cleaning liquid to the web, and a second supply unit that supplies the second cleaning liquid to the web. In this case, it is preferable that the first supply unit and the second supply unit supply the first cleaning liquid and the second cleaning liquid alternately.
[0016] In the cleaning apparatus based on the above disclosure, the cleaning unit may include a first cleaning unit that cleans the ejection surface of the inkjet head using the first cleaning solution, and a second cleaning unit that cleans the ejection surface using the second cleaning solution.
[0017] In the cleaning apparatus based on the above disclosure, the first cleaning unit and the second cleaning unit are preferably one of a web-type cleaning unit, a roller-type cleaning unit, and a nozzle-type cleaning unit. In this case, the web-type cleaning unit preferably includes a web that moves while in contact with the discharge surface and a first supply unit that supplies the first cleaning liquid to the web. The roller-type cleaning unit preferably includes a roller to which the first cleaning liquid is supplied and which moves while in contact with the discharge surface. The nozzle-type cleaning unit preferably includes a nozzle that sprays the second cleaning liquid toward the discharge surface and a blade that moves while in contact with the discharge surface and scrapes off the second cleaning liquid adhering to the discharge surface.
[0018] In the cleaning apparatus based on the above disclosure, the first cleaning unit may be either the web-type cleaning unit or the roller-type cleaning unit, and the second cleaning unit may be the nozzle-type cleaning unit.
[0019] In the cleaning apparatus based on the above disclosure, the amount of the first cleaning solution supplied to the ejection surface of the inkjet head may be greater than the amount of the second cleaning solution supplied to the ejection surface.
[0020] In the cleaning apparatus based on the above disclosure, multiple inkjet heads are provided for each color. hand This is also acceptable. In this case, the cleaning unit may be configured to switch between a first cleaning mode in which the inkjet head is cleaned using the first cleaning solution and the second cleaning solution, and a second cleaning mode in which the inkjet head is cleaned using only the first cleaning solution. Furthermore, in this case, one of the plurality of inkjet heads may be cleaned using only the first cleaning solution. [Effects of the Invention]
[0021] According to the present disclosure, it is possible to provide a cleaning method and a cleaning device for an inkjet head that can remove foreign matter while suppressing the generation of aggregates.
Brief Description of the Drawings
[0022] [Figure 1] It is a diagram showing a state where foreign matter exists in the ejection opening of the inkjet head according to Embodiment 1. [Figure 2] It is a flowchart showing the flow of the cleaning method of the inkjet head according to Embodiment 1. [Figure 3] It is a schematic diagram showing the first cleaning part constituting the cleaning part of the cleaning device according to Embodiment 1. [Figure 4] It is a schematic diagram showing the second cleaning part constituting the cleaning part of the cleaning device according to Embodiment 1. [Figure 5] It is a schematic diagram showing the first modification example of the first cleaning part and / or the second cleaning part. [Figure 6] It is a schematic diagram showing the second modification example of the first cleaning part and / or the second cleaning part. [Figure 7] It is a diagram showing a modification example of the cleaning part. [Figure 8] It is a flowchart showing the flow of the cleaning method of the inkjet head according to Embodiment 2. [Figure 9] In the flow shown in FIG. 8, it is a diagram showing the state after the step of gelling the ink in the inkjet. [Figure 10] In the flow shown in FIG. 8, it is a diagram showing the state after the step of supplying the first cleaning liquid to the ejection surface of the inkjet head. [Figure 11] In the flow shown in FIG. 8, it is a diagram showing the state after the step of supplying the second cleaning liquid to the ejection surface of the inkjet head. [Figure 12] In the flow shown in FIG. 8, it is a diagram showing the state after the step of removing the second cleaning liquid remaining on the ejection surface of the inkjet head. [Figure 13]This figure shows the state after the ink ejection process from the inkjet head in the flow shown in Figure 8. [Modes for carrying out the invention]
[0023] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.
[0024] (Embodiment 1) Figure 1 shows the presence of foreign matter inside the ejection port of the inkjet head according to Embodiment 1.
[0025] As shown in Figure 1, the inkjet head 10 includes a main body 11. The main body 11 is provided with an ejection port 10h and a flow path 10p communicating with the ejection port 10h. The inkjet head 10 has an ejection surface 10a on which the ejection port 10h is provided.
[0026] In the inkjet head 10, foreign matter F may precipitate or adhere to the ejection port 10h. In this embodiment, the case in which the foreign matter F is a water-soluble precipitate that precipitates from the ink I will be used as an example to describe the cleaning method and cleaning apparatus for the inkjet head 10.
[0027] Figure 2 is a flowchart showing the flow of the inkjet head cleaning method according to Embodiment 1.
[0028] As shown in Figure 2, the method for cleaning the inkjet head 10 according to Embodiment 1 includes the steps of cleaning the inkjet head using a first cleaning solution and a second cleaning solution (S10), and the inkjet head A step (S20) to remove the cleaning solution remaining on the ejection surface of the inkjet printer, and head This includes the step of ejecting ink (S30).
[0029] In step (S10), the inkjet head 10 is cleaned using a cleaning device. This cleaning device uses a first cleaning solution W1 (see Figure 3) and a second cleaning solution W2 (See Figure 4) The system includes a cleaning unit for cleaning the inkjet head 10.
[0030] In carrying out process (S10), first, in process (S11), the first cleaning solution W1 is supplied to the ejection surface 10a of the inkjet head.
[0031] Figure 3 is a schematic diagram showing the first cleaning section that constitutes the cleaning section of the inkjet head device according to Embodiment 1.
[0032] As shown in Figure 3, the first cleaning unit 20 of the cleaning device may be a web-type cleaning unit. In this case, the first cleaning unit 20 includes an unwinding roller 21, a winding roller 22, a web 23 made of a strip of fabric, a pressing member 24, and a first supply unit 25.
[0033] The web 23 is pre-wound onto the unwinding roller 21. The web 23 is bridged between the unwinding roller 21 and the winding roller 22, passing between the pressing member 24 and the discharge surface 10a.
[0034] The first supply unit 25 includes a supply roller 26 and a storage tank 27. The storage tank 27 stores the first cleaning liquid W1. The supply roller 26 pumps up the first cleaning liquid W1 stored in the storage tank 27 and supplies it to the web 23.
[0035] As the winding roller 22 rotates and winds up the web 23, the web 23 moves from the unwinding roller 21 towards the winding roller 22. During this process, the first cleaning liquid W1 is supplied by the supply roller 26, and the web 23 moves while in contact with the discharge surface 10a. This supplies the first cleaning liquid W1 to the discharge surface 10a of the inkjet head 10. Furthermore, by pressing the web 23 toward the discharge surface 10a with the pressing member 24, the state in which the web 23 is in contact with the discharge surface 10a can be maintained.
[0036] As the first cleaning solution W1, it is preferable to use a solvent that can maintain the dispersion state of the ink. For example, the same solvent as the ink solvent can be used as such a solvent.
[0037] When using a UV-curable ink containing a vinyl ether compound, a (meth)acryloyl group-containing compound, and a photoacid generator as a photopolymerization initiator, a cleaning solution (solvent) containing the vinyl ether compound and the (meth)acryloyl group-containing compound is preferred. More specifically, the first cleaning solution W1 preferably contains the same or similar type of vinyl ether compound and the (meth)acryloyl group-containing compound as the ink.
[0038] The first cleaning solution W1 supplied to the discharge surface 10a penetrates into the discharge port 10h provided on the discharge surface 10a. By using the above-mentioned solution as the first cleaning solution W1, the dispersion state of the ink can be maintained. Furthermore, if the ink has become thickened or the pigment has aggregated, the first cleaning solution W1 can resolve the thickening of the ink and / or the aggregation of the pigment.
[0039] Next, as shown in Figure 2, in step (S12), the second cleaning solution W2 is supplied to the ejection surface 10a of the inkjet head 10.
[0040] Figure 4 is a schematic diagram showing the second cleaning section that constitutes the cleaning section of the inkjet head device according to Embodiment 1.
[0041] As shown in Figure 4, the second cleaning unit 30 of the cleaning device may be a web-type cleaning unit. In this case, the second cleaning unit 30 includes an unwinding roller 31, a winding roller 32, a web 33 made of a strip of fabric, a pressing member 34, and a second supply unit 35.
[0042] The web 33 is pre-wound onto the unwinding roller 21. The web 33 is bridged between the unwinding roller 21 and the winding roller 32, passing between the pressing member 34 and the discharge surface 10a.
[0043] The second supply unit 35 includes a supply roller 36 and a storage tank 37. The storage tank 37 stores the second cleaning liquid W2. The supply roller 36 pumps up the second cleaning liquid W2 stored in the storage tank 37 and supplies it to the web 33.
[0044] As the winding roller 32 rotates and winds up the web 33, the web 33 moves from the unwinding roller 31 towards the winding roller 32. During this process, the web 33 moves while in contact with the discharge surface 10a, with the supply roller 36 supplying the second cleaning fluid W2. This ensures that the second cleaning fluid W2 is supplied to the discharge surface 10a of the inkjet head 10. Furthermore, by pressing the web 33 toward the discharge surface 10a with the pressing member 34, the state in which the web 33 is in contact with the discharge surface 10a can be maintained.
[0045] Water can be used as the second washing solution W2. The water can be pure water such as ion-exchanged water, limit filtered water, reverse osmosis water, or distilled water, or ultrapure water. Alternatively, water sterilized by ultraviolet irradiation, hydrogen peroxide addition, etc., may be used.
[0046] The second cleaning liquid W2 supplied to the discharge surface 10a enters the discharge port 10h provided on the discharge surface 10a. At this time, by using the above-mentioned second cleaning liquid W2, water-soluble foreign matter F can be dissolved.
[0047] Next, as shown in Figure 2, in step (S20), the second cleaning solution remaining on the ejection surface 10a of the inkjet head 10 is removed. The remaining second cleaning solution W2 may contain a portion of the first cleaning solution W1.
[0048] The second cleaning unit 30 described above may be configured to switch between a supply state in which the supply roller 36 contacts the web 33 and supplies the second cleaning liquid W2 to the web 33, and a non-supply state in which the supply roller 36 is separated from the web 33 and the second cleaning liquid W2 cannot be supplied to the web 33. In this case, in the non-supply state, the cleaning liquid remaining on the discharge surface 10a can be removed by sliding the web 33, which is not supplied with the second cleaning liquid W2, against the discharge surface 10a.
[0049] Alternatively, instead of the web 33, an absorbent material capable of absorbing cleaning liquid, such as a sponge, may be slid across the discharge surface 10a to remove the second cleaning liquid remaining on the discharge surface 10a. This prevents the remaining second cleaning liquid from entering the discharge port 10h.
[0050] Next, as shown in Figure 2, in step (S30), ink I is ejected from the inkjet head (more specifically, the ejection port 10h). Specifically, the ink I, which has been purged and mixed with the second cleaning solution W2, is ejected from the ejection port 10h. This cleans the ejection port 10h of the inkjet head 10 and fills the ejection port 10h with ink I.
[0051] The first cleaning section 20 and the second cleaning section 30 described above are merely examples and may be modified as shown below.
[0052] Figure 5 is a schematic diagram showing a first modified example of the first cleaning section and / or the second cleaning section.
[0053] As shown in Figure 5, the first cleaning unit 20 and / or the second cleaning unit 30 may be a nozzle-type cleaning unit. This nozzle-type cleaning unit includes a nozzle 41, a storage tank 42, piping 43, and a blade 45.
[0054] The nozzle section 41 is positioned facing the discharge surface 10a. The nozzle section 41 is configured to eject cleaning liquid onto the discharge surface 10a. The storage tank 42 stores cleaning liquid (specifically, the first cleaning liquid W1 or the second cleaning liquid W2). The nozzle section 41 is connected to the piping 43. The end of the piping 43 on the opposite side from where the nozzle section 41 is located is in the cleaning liquid stored in the storage tank 42. The nozzle section 41 sprays the cleaning liquid transported by the piping 43 onto the discharge surface 10a.
[0055] The nozzle portion 41 is provided so as to be movable along the surface direction of the discharge surface 10a (for example, in the direction of arrow AR1 in Figure 5) by a moving mechanism (not shown). As the nozzle portion 41 moves and sprays the cleaning liquid, the cleaning liquid can be sprayed evenly across the discharge surface 10a.
[0056] The blade 45 is also provided to move along the direction of arrow AR1 in Figure 5 by a moving mechanism. By scraping off the cleaning liquid ejected toward the discharge surface 10a with the blade 45, the cleaning liquid supplied to the discharge surface 10a can be made uniform across the surface.
[0057] The cleaning fluid may be supplied to the inkjet head using a nozzle-type cleaning unit as described above. In particular, when using the second cleaning fluid W2, since the second cleaning fluid W2 is water, it has little effect on the surroundings even when ejected from the nozzle section 41.
[0058] Figure 6 is a schematic diagram showing a second modified example of the first cleaning unit and / or the second cleaning unit.
[0059] As shown in Figure 6, the first cleaning unit 20 and / or the second cleaning unit 30 may be a roller-type cleaning unit. This roller-type cleaning unit includes a supply roller 51 and a storage tank 52. The supply roller 51 rotates and supplies the cleaning liquid (specifically, the first cleaning liquid W1 or the second cleaning liquid W2) stored in the storage tank 52 to the discharge surface 10a.
[0060] The supply roller 51 and the storage tank 52 are provided to be movable along the planar direction of the discharge surface 10a (for example, in the direction of arrow AR1 in Figure 6). The supply roller 51 can supply the cleaning fluid evenly to the discharge surface 10a by moving while in contact with the discharge surface 10a.
[0061] Furthermore, although the above example illustrates a case where the cleaning unit includes two cleaning units (a first cleaning unit 20 and a second cleaning unit 30), it may also be a single unit as described below.
[0062] Figure 7 shows a modified example of the cleaning unit. In this case, the cleaning unit 60 includes an unwinding roller 61, a winding roller 62, a web 63 made of a strip of fabric, a pressing member 64, a first supply unit 65, and a second supply unit 75.
[0063] The web 63 is pre-wound onto the unwinding roller 61. The web 63 is bridged between the unwinding roller 61 and the winding roller 62, passing between the pressing member 64 and the discharge surface 10a.
[0064] The first supply unit 65 includes a supply roller 66 and a storage tank 67. The storage tank 67 stores the first cleaning liquid W1. The supply roller 66 pumps up the first cleaning liquid W1 stored in the storage tank 67 and supplies it to the web 63.
[0065] The first supply unit 65 is configured to switch between a supply state in which the supply roller 66 contacts the web 63 and supplies the first cleaning liquid W1 to the web 63, and a non-supply state in which the supply roller 66 is separated from the web 63 and the first cleaning liquid W1 cannot be supplied to the web 63. The supply state and non-supply state of the first supply unit 65 are switched by the control unit of the cleaning unit 60.
[0066] The second supply unit 75 includes a supply roller 76 and a storage tank 77. The storage tank 77 stores the second cleaning liquid W2. The supply roller 76 pumps up the second cleaning liquid W2 stored in the storage tank 77 and supplies it to the web 63. The second supply unit 75 is located downstream of the first supply unit 65 and upstream of the discharge surface 10a and the pressing member 64 in the direction of movement of the web 63.
[0067] The second supply unit 75 is provided in a way that it can switch between a supply state in which the supply roller 76 is in contact with the web 63 and the second cleaning liquid W2 is supplied to the web 63, and a non-supply state in which the supply roller 76 is separated from the web 63 and the second cleaning liquid W2 cannot be supplied to the web 63.
[0068] The first supply unit 65 and the second supply unit 75 can switch between supply and non-supply states as appropriate to alternately supply the first cleaning liquid W1 and the second cleaning liquid W2 to the web 63. For example, when the web 63 is moving toward the winding roller 62, the first supply unit 65 is in the supply state and is supplying the first cleaning liquid W1 to the web 63, while the second supply unit 75 is in the non-supply state.
[0069] After the first supply unit 65 supplies the first cleaning liquid W1 to the web 63 for a predetermined period, the first supply unit 65 is switched to a non-supply state. Subsequently, after the portion of the web 63 supplied with the first cleaning liquid W1 by the first supply unit 65 has passed through the second supply unit 75, the second supply unit 75 is switched to a supply state and the second cleaning liquid W2 is supplied to the web 63. This allows the first cleaning liquid W1 and the second cleaning liquid W2 to be supplied to the discharge surface 10a in this order.
[0070] In the above description, the first supply unit 65 is located upstream of the second supply unit 75 in the direction of movement of the web 63, but it may also be located downstream of the second supply unit 75. In this case, the first supply unit 65 is set to supply state and the first cleaning liquid W1 is supplied to the web 63, and the second supply unit 75 is set to supply state so as to follow the first cleaning liquid W1 supplied from the first supply unit 65. Before the second cleaning liquid W2 reaches the first supply unit 65, the first supply unit 65 is switched to a non-supply state. After supplying the second cleaning liquid W2 to the web 63 for a predetermined period, the second supply unit 75 is switched to a non-supply state. This allows the first cleaning liquid W1 and the second cleaning liquid W2 to be supplied to the discharge surface 10a in this order.
[0071] In the above example, foreign matter F is shown as a water-soluble substance formed by the precipitation of components of ink I. However, foreign matter F may also be thickened ink I, aggregates formed by the aggregation of pigments in ink I, or a mixture of these with the water-soluble substance. Furthermore, the water-soluble foreign matter is not limited to the precipitation of components of ink I, but may be other water-soluble substances.
[0072] As in Embodiment 1, by supplying the first cleaning solution W1 to the ejection surface 10a of the inkjet head 10, the viscosity of the ink I and / or the aggregation of pigments can be eliminated by the first cleaning solution W1. In this case, by using a solvent that can maintain the dispersion state of the ink I as the first cleaning solution W1, the generation of aggregates can be suppressed. Furthermore, by supplying the second cleaning solution W2 to the ejection surface 10a of the inkjet head 10, water-soluble foreign matter can be dissolved.
[0073] Furthermore, by removing the second cleaning solution W2 remaining on the discharge surface 10a, it is possible to prevent the second cleaning solution from unnecessarily entering the discharge port 10h. In addition, after cleaning with the second cleaning solution W2, ink I is discharged from the discharge port 10h to expel the second cleaning solution W2 that has entered the discharge port 10h to the outside, and the inside of the discharge port 10h is filled with ink I, thereby preventing the dispersion state of ink I within the inkjet head 10 from being disrupted.
[0074] (Embodiment 2) Figure 8 is a flowchart showing the flow of the inkjet head cleaning method according to Embodiment 2. The inkjet head cleaning method according to Embodiment 2 will be described with reference to Figure 8. In Embodiment 2, the example given is that the foreign matter F is water-soluble.
[0075] As shown in Figure 8, the inkjet head cleaning method according to Embodiment 2 differs from the inkjet head cleaning method according to Embodiment 1 mainly in that it includes a step (S1) to gel the ink in the inkjet. The other steps are substantially the same.
[0076] In carrying out the inkjet head cleaning method according to Embodiment 2, first, in step (S1), at least within the ejection port 10h position The ink I (see Figure 9) is gelled. Specifically, the main body 11 is cooled using a cooler, and the ink I inside the main body 11 is cooled to below the sol-gel transition point (freezing point). Ink I containing wax is preferably used. Furthermore, foreign matter F is present inside the gelled ink I.
[0077] Figure 9 shows the state after the process of gelling the ink in the inkjet, as shown in Figure 8. As shown in Figure 9, in the state after the process of gelling the ink in the inkjet, the ink I gels, and gaps 81 are formed between the gelled ink I. By gelling at least the ink I in the ejection port 10h, it becomes difficult for liquids other than the ink solvent, such as water, to enter the ejection port 10h.
[0078] Next, as shown in Figure 8, in step (S10), the inkjet head 10 is cleaned using the first cleaning solution W1 and the second cleaning solution W2. Specifically, in step (S11), the first cleaning solution W1 is supplied to the ejection surface 10a of the inkjet head in substantially the same manner as the cleaning method according to Embodiment 1.
[0079] Figure 10 shows the state after the step of supplying the first cleaning solution to the ejection surface of the inkjet head, in the flow shown in Figure 8. As shown in Figure 10, after the step of supplying the first cleaning solution W1 to the ejection surface 10a of the inkjet head 10, the gaps 81 of the gelled ink I are filled with the first cleaning solution.
[0080] Next, as shown in Figure 8, in step (S12), the second cleaning solution W2 is supplied to the ejection surface 10a of the inkjet head 10 in substantially the same manner as the cleaning method according to Embodiment 1.
[0081] Figure 11 shows the state after the step of supplying the second cleaning solution W2 to the ejection surface 10a of the inkjet head 10, in the flow shown in Figure 8. As shown in Figure 11, in the state after the step of supplying the second cleaning solution W2 to the ejection surface 10a of the inkjet head 10, a portion of the second cleaning solution W2 penetrates into the ejection port 10h, and the foreign matter F dissolves in the second cleaning solution W2.
[0082] Next, as shown in Figure 8, in step (S20), the second cleaning solution W2 remaining on the ejection surface 10a of the inkjet head 10 is removed, in substantially the same manner as in Embodiment 1.
[0083] Figure 12 shows the state after the step of removing the second cleaning solution remaining on the ejection surface of the inkjet head, in the flow shown in Figure 8. As shown in Figure 12, in the state after the step of removing the second cleaning solution W2 remaining on the ejection surface 10a of the inkjet head 10, the second cleaning solution W2 adhering to the ejection surface 10a is removed, and the second cleaning solution W2 remains inside the ejection port 10h on the open end side.
[0084] Next, as shown in Figure 8, in step (S30), ink I is ejected from the inkjet head (more specifically from the ejection port 10h). Specifically, the main body 11 is heated using a heater or other heating device to raise the ink I inside the main body 11 to above its sol-gel transition temperature. Subsequently, it is purged, and the ink I mixed with the second cleaning solution W2 is ejected from the ejection port 10h.
[0085] Figure 13 shows the state after the ink ejection process from the inkjet head, as shown in the flow diagram in Figure 8. As shown in Figure 13, after the ink I is ejected from the inkjet head 10, the ejection port 10h of the inkjet head 10 is cleaned and the ejection port 10h is filled with ink.
[0086] Even when cleaning the inkjet head 10 as in Embodiment 2, substantially the same effects as in Embodiment 1 can be obtained.
[0087] (Other variations) In the embodiments 1 and 2 and their respective modifications described above, the example illustrates the cleaning of a single inkjet head 10. However, the cleaning method and cleaning apparatus can also be applied when multiple inkjet heads 10 are provided for each color. In this case, the cleaning unit may be switchable between a first cleaning mode in which the inkjet head 10 is cleaned using a first cleaning solution W1 and a second cleaning solution W2, and a second cleaning mode in which the inkjet head 10 is cleaned using only one of the first cleaning solution W1 or the second cleaning solution. The first and second cleaning modes can be switched by the control unit of the cleaning apparatus. Furthermore, in this case, one of the multiple inkjet heads 10 may be cleaned using the second cleaning mode.
[0088] Specifically, for example, in inkjet heads that handle inks of a color where water-soluble precipitates are easily formed and ink thickening and pigment aggregation are less likely to occur, the second cleaning mode may be used to clean using only the second cleaning solution. Also, in inkjet heads that handle inks of a color where water-soluble precipitates are less likely to form and ink thickening and pigment aggregation are easily formed, the second cleaning mode may be used to clean using only the first cleaning solution. On the other hand, in inkjet heads that handle inks of a color where water-soluble precipitates are easily formed and ink thickening and pigment aggregation are also easily formed, the first cleaning mode may be used to clean using both the first and second cleaning solutions.
[0089] The embodiments and modifications disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]
[0090] 10 Inkjet head, 10a Discharge surface, 10h Discharge port, 10p Flow path, 11 Main body, 20 First cleaning section, 21 Unwinding roller, 22 Rewinding roller, 23 Web, 24 Pressing member, 25 First supply section, 26 Supply roller, 27 Storage tank, 30 Second cleaning section, 31 Unwinding roller, 32 Rewinding roller, 33 Web, 34 Pressing member, 35 Second supply section, 41 Nozzle section, 43 Piping, 45 Blade, 36 Supply roller, 37 Storage tank, 60 Cleaning section, 61 Unwinding roller, 62 Rewinding roller, 63 Web, 64 Pressing member, 65 First supply section, 66 Supply roller, 67 Storage tank, 75 Second supply section, 76 Supply roller, 77 Storage tank, 81 Gap, F Foreign matter, I Ink, W1 First cleaning solution, W2 second cleaning solution.
Claims
1. The inkjet head is cleaned using a first cleaning solution capable of maintaining the dispersion state of the ink, and a second cleaning solution having a solvent different from the ink. A step of supplying the first cleaning solution to the ejection surface of the inkjet head, The process includes the step of supplying the first cleaning solution to the discharge surface, followed by the step of supplying the second cleaning solution to the discharge surface, Using an ink containing wax, A method for cleaning an inkjet head, further comprising the step of gelling the ink located at least within the ejection port of the inkjet head before supplying the first cleaning solution to the ejection surface.
2. The method for cleaning an inkjet head according to claim 1, wherein the first cleaning solution is composed of the same solvent as the ink.
3. The method for cleaning an inkjet head according to claim 1, further comprising the step of supplying the second cleaning solution to the discharge surface, followed by the step of discharging the ink from the inkjet head.
4. The method for cleaning an inkjet head according to claim 1, further comprising the step of removing the second cleaning solution remaining on the discharge surface after the step of supplying the second cleaning solution to the discharge surface.
5. A UV-curing ink is used as the aforementioned ink. The method for cleaning an inkjet head according to claim 1 or 2, wherein water is used as the second cleaning solution.
6. A cleaning device for cleaning an inkjet head, The system includes a cleaning unit for cleaning the inkjet head using a first cleaning solution capable of maintaining the dispersion state of the ink and a second cleaning solution having a solvent different from the ink. The cleaning unit supplies the first cleaning solution to the ejection surface of the inkjet, and then supplies the second cleaning solution to the ejection surface. The aforementioned ink contains wax, A cleaning apparatus further comprising a cooler that gels the ink, located at least within the ejection port of the inkjet head, before supplying the first cleaning solution to the ejection surface.
7. The cleaning unit includes a web that moves while in contact with the ejection surface of the inkjet head, a first supply unit that supplies the first cleaning solution to the web, and a second supply unit that supplies the second cleaning solution to the web. The cleaning apparatus according to claim 6, wherein the first supply unit and the second supply unit alternately supply the first cleaning liquid and the second cleaning liquid.
8. The cleaning apparatus according to claim 6, wherein the cleaning unit includes a first cleaning unit that cleans the ejection surface of the inkjet head using the first cleaning solution, and a second cleaning unit that cleans the ejection surface using the second cleaning solution.
9. The first cleaning unit and the second cleaning unit are one of a web-type cleaning unit, a roller-type cleaning unit, and a nozzle-type cleaning unit. The web-type cleaning unit includes a web that moves while in contact with the discharge surface, and a first supply unit that supplies the first cleaning liquid to the web. The roller-type cleaning unit includes a roller to which the first cleaning fluid is supplied and which moves while in contact with the discharge surface, The cleaning apparatus according to claim 8, wherein the nozzle-type cleaning unit includes a nozzle portion that sprays the second cleaning liquid toward the discharge surface, and a blade that moves while in contact with the discharge surface and scrapes off the second cleaning liquid adhering to the discharge surface.
10. The first cleaning unit is either the web-type cleaning unit or the roller-type cleaning unit. The cleaning apparatus according to claim 9, wherein the second cleaning unit is the nozzle-type cleaning unit.
11. The cleaning apparatus according to any one of claims 6 to 10, wherein the amount of the first cleaning solution supplied to the ejection surface of the inkjet head is greater than the amount of the second cleaning solution supplied to the ejection surface.
12. Multiple inkjet heads are provided for each color. The cleaning unit is configured to be switchable between a first cleaning mode in which the inkjet head is cleaned using the first cleaning solution and the second cleaning solution, and a second cleaning mode in which the inkjet head is cleaned using only either the first cleaning solution or the second cleaning solution. The cleaning apparatus according to claim 6, wherein one of the plurality of inkjet heads is cleaned in the second cleaning mode.