Inkjet recording device

Abstract

To provide an inkjet recording device, which is configured to reduce unwiped ink to improve cleaning performance when wiping ink adhering to a nozzle surface of an inkjet head, with a textile fabric.SOLUTION: An inkjet recording device (1) comprises: an inkjet head (10) that discharges ink from a nozzle; and a cloth wipe unit (20) having a textile fabric (21) for wiping a nozzle surface (11a) of an opened discharge port (n) of a nozzle of the inkjet head, which is configured so that relative sliding of the textile fabric and the nozzle surface can wipe ink adhering to the nozzle surface. Mountain parts (m) formed on surfaces by yarns (warp yarns a) passing on cross yarns (weft yarns b) of the textile fabric are made to slide-rub any discharge port while sliding.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Conventionally, there is an inkjet recording device that records an image by ejecting ink from the nozzles of an inkjet head and landing the ink at a desired position on a recording medium. When ink adheres to the nozzle surface of the inkjet head, the adhered ink thickens and further solidifies while partially blocking the nozzle orifices, causing ink ejection failure. A cloth wiping method in which a woven fabric and the nozzle face are slid relative to each other to wipe off residual ink from the nozzle face, and a cleaning device that performs this method are known and used (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6162344 [Patent Document 2] JP 2018-79619 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques do not solve the following problems. The weave structure of a plain weave fabric is shown in Figures 4 and 5. When observing the surface of the woven fabric as shown in Figures 4 and 5, ridges m are formed on the surface by warp thread a passing over weft thread b. Ridges m are formed on the surface by weft thread b passing over warp thread a. Between parallel weft threads b and weft threads b, valleys va and gaps run parallel to weft thread b, resulting in positions where ridges m are not located. Between parallel warp threads a and warp threads a, valleys vb run parallel to warp thread a, resulting in positions where ridges m are not located. Therefore, even if the nozzle outlet n is rubbed at a position where the above-mentioned valleys and gaps are continuous and no peaks are arranged, the thickened ink around the outlet n cannot be sufficiently scraped off.

[0005] The present invention has been made in consideration of the above-mentioned problems in the conventional technology, and has an object to reduce the amount of ink left behind when wiping ink adhering to the nozzle surface of an inkjet head with a woven cloth, thereby improving cleaning performance. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an inkjet recording apparatus comprising an inkjet head which ejects ink from nozzles, and a cloth wiping unit having a woven cloth which wipes a nozzle surface on which the ejection ports of the nozzles of the inkjet head are opened, the woven cloth having a structure in which a valley portion formed on a surface by a thread passing from below to above or from above to below a crossing thread is continued at a position parallel to the crossing thread, and during the sliding, 、 In a plan view, in the direction perpendicular to the sliding direction 、 The woven fabric Weft Half-pick Send only This is an inkjet recording device that wipes off ink adhering to the nozzle surface by relative sliding between the woven fabric and the nozzle surface, and the ridges formed on the surface by threads passing over the crossing threads of the woven fabric are rubbed against each of the ejection ports. Effect of the Invention

[0007] According to the present invention, when wiping off ink adhering to the nozzle face of an inkjet head with a woven cloth, the amount of ink left unwiped can be reduced, improving cleaning properties. [Brief description of the drawings]

[0008] [Figure 1] 1 is a front view showing a head and a cloth wiping unit of an inkjet recording apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a side view showing a head and a cloth wiping unit of an inkjet recording apparatus according to an embodiment of the present invention; [Diagram 3] 1 is a block diagram showing main operating elements of an inkjet recording apparatus according to an embodiment of the present invention; [Figure 4] 1A is a longitudinal cross-sectional view, FIG. 1B is a plan view, and FIG. 1C is a cross-sectional view of a plain weave fabric. [Diagram 5] This is a diagram of the structure of a plain weave fabric. [Figure 6] FIG. 2 is a plan view (a) and a cross-sectional view (b) of a twill weave fabric. [Figure 7] This is a diagram of the weave of a twill fabric. [Figure 8] This is a diagram of the weave of a satin weave fabric. [Figure 9] 1A is a longitudinal section view, FIG. 1B is a structure diagram, and FIG. 1C is a transverse section view of a woven fabric made by an example of a highly irregular weave. [Figure 10] 1 is a table showing the results of evaluation of the intersecting angle between the sliding direction and the warp threads and the ink scraping property. [Figure 11] 11 is a table showing the results of evaluation of the pressing force of the nozzle face against the woven fabric, the ink scraping property, and the wear of the nozzle face. [Figure 12] 1 is a table showing the results of evaluation of weft density, ink scraping property, and ink absorption property into woven fabric. [Figure 13] 1 is a table showing the results of evaluation of the thickness of the woven fabric and the staining of the backup member. [Figure 14] 11 is a table showing the results of evaluation of the relative speed between the nozzle face and the woven fabric, the ink scraping performance, and the staining of the backup member. [Figure 15] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. The following is an embodiment of the present invention, and is not intended to limit the present invention.

[0010] [Outline of Inkjet Recording Apparatus] As shown in FIGS. 1 and 2, the inkjet recording apparatus 1 includes an inkjet head 10 and a cloth wiping unit 20. The ... head 10 includes a cloth wiping unit 20. The inkjet head 10 ejects ink from nozzles. The ejection openings of the nozzles of the inkjet head 10 are opened in a nozzle surface 11a of a nozzle plate 11, and a plurality of nozzles are arranged in the X direction. The cloth wiping unit 20 has a woven cloth 21 that wipes the nozzle surface 11a. The cloth wiping unit 20 holds a wiping surface 21a of the woven cloth 21 on an XY plane parallel to the nozzle surface 11a. In this embodiment, the woven cloth 21 is a long object wound into a roll, unwound from an unwinding roller 22, and stretched between support rollers 23 and 24 to form the wiping surface 21a at a predetermined position, and after wiping, is taken up by a take-up roller 25. A backup member 26 is arranged on the back side of the wiping surface 21a to resist the pressing force from the nozzle surface 21a to the wiping surface 21a.

[0011] FIG. 3 shows a block diagram of the main operating elements of the inkjet recording apparatus 1. As shown in FIG. The control unit 40 is a processor that controls the overall operation of the inkjet recording apparatus 1. The control unit 40 includes, for example, a CPU 41 (Central Processing Unit) and a RAM 42 (Random Access Memory). The CPU 41 performs calculations and various control processes. The RAM 42 provides a working memory space for the CPU 41 and stores temporary data.

[0012] The inkjet head 10 is mounted on a carriage and is movable in the X direction. A control unit 40 controls the inkjet head driving unit 15, the carriage driving unit 35, and the recording medium transport unit 55 to perform a recording operation. The control unit 40 suspends the recording operation, and controls the carriage drive unit 35 and the cloth wiping unit drive unit 29 to wipe and clean the nozzle surface 11a, thereby placing the inkjet head 10 at the cloth wiping position as shown in Figures 1 and 2. At the cloth wiping position shown in Figures 1 and 2, the nozzle surface 11a is pressed against the wiping surface 21a, although this is not shown in the figures. This pressing is achieved by the function of lifting and lowering the carriage by the carriage drive unit 35, or the function of lifting and lowering the cloth wiping unit 20 by the cloth wiping unit drive unit 29, or the like.

[0013] With the nozzle surface 11a pressed against the wiping surface 21a, the control unit 40 further controls the carriage drive unit 35 to perform a wiping operation by reciprocating the inkjet head 10 in the X direction, thereby causing relative sliding between the fabric 21 and the nozzle surface 11a, which in turn wipes away ink adhering to the nozzle surface 11a. In the sliding direction X, the dimension W2 of the woven cloth 21 exceeds the dimension W1 of the nozzle plate 11 having the nozzle surface 11a plus the sliding distance T1. Under these conditions, the entire surface of the nozzle surface 11a always contacts the woven cloth 21 during the wiping operation, improving cleaning performance.

[0014] [Application to various woven fabrics] Next, the application of fabrics of various constructions will be described. Figure 4 shows a plain weave fabric 21A. Figure 5 shows a structure diagram of the plain weave fabric 21A. The warp threads are represented by a and the weft threads by b, and are individually numbered, with the warp pitch being pa and the weft pitch being pb (same below). The threads passing over the crossing threads of the woven fabric 21A form a ridge m on the surface. The ridge m is located at the center of the square in the structure diagram of FIG. In the woven fabric 21A, a valley v is formed on the surface by a yarn passing from below to above or from above to below the crossing yarn. Here, the crossing yarn for the warp yarn a is the weft yarn b, and the crossing yarn for the weft yarn b is the warp yarn a. Therefore, a valley va is formed on the surface by the warp yarn a passing from below to above or from above to below the weft yarn b. A valley vb is formed on the surface by the weft yarn b passing from below to above or from above to below the warp yarn a. In FIG. 5, the valley va is marked on the surface by a white circle by the warp yarn a passing from below to above or from above to below the weft yarn b. It can then be confirmed that the valley va continues in the X direction, which is the sliding direction. The plain weave fabric 21A has a structure in which the valleys va (vb) formed on the surface by the threads a(b) passing from below to above or from above to below the crossing threads b(a) have a continuous valley structure, with no peaks m located parallel to the crossing threads b(a). As shown in FIG. 5, if the ejection opening n of the nozzle slides at the position of this valley va, the ink at the ejection opening n and its surroundings cannot be sufficiently scraped off.

[0015] In the inkjet recording apparatus 1, the peaks m are made to rub against all of the ejection ports n during the wiping operation. In other words, there is no ejection port n that is not rubbed against the peaks m even after the wiping operation. When a plain weave woven cloth 21A is used, during the wiping operation in which the nozzle surface 11a and the wiping surface 21a slide against each other, the woven cloth 21A can be fed in the Y direction by more than half a pitch (1 / 2 x pb) so that the ridge m rubs against each of the nozzle outlets n. The control unit 40 controls the carriage driving unit 35 and the cloth feed unit of the cloth wiping unit driving unit 29 to perform the wiping operation in which the sliding in the X direction and the cloth feed in the Y direction are performed.

[0016] Fig. 6 shows the twill weave fabric 21B, and Fig. 7 shows the structure of the twill weave fabric 21B. As shown in Figures 6 and 7, the twill weave fabric 21B has a structure in which a valley va is formed on the surface by a thread a passing from bottom to top or from top to bottom of a crossing thread b, and a peak m is located parallel to the crossing thread b (structure condition 1). Therefore, if the nozzle orifice n slides at the position of this valley va as shown in FIG. 7, the orifice n will also be rubbed against the peak m, so that the ink at and around the orifice n can be sufficiently scraped off. The inkjet recording device 1 uses such a twill woven fabric 21B, and performs a wiping operation on the nozzle surface 11a under the control of the control unit 40 with the weft direction X as the sliding direction. In this case, the sliding direction X intersects with the warp thread a, the sliding distance T1 is equal to or greater than two pitches (2×pa) of the warp thread a, and the woven fabric 21B has at least one peak m of the warp thread a within the sliding distance T1. FIG. 6 shows an example of a 2 / 2 twill weave, and FIG. 7 shows an example of a 2 / 1 twill weave. Since tension is applied to the warp threads a by the support of the woven fabric 21 by the fabric wiping unit 20, the ink is scraped off by the peaks of the warp threads a in this manner.

[0017] FIG. 8 shows a satin weave fabric 21C. The weave of the satin weave fabric 21C also satisfies the weave condition 1. Therefore, if the nozzle orifice n slides at the position of this valley va as shown in FIG. 8, the orifice n is also rubbed against the peak m, so that the ink at and around the orifice n can be sufficiently scraped off. The inkjet recording device 1 uses such a twill woven fabric 21C, and performs a wiping operation on the nozzle surface 11a under the control of the control unit 40 with the weft direction X as the sliding direction. In this case, the sliding direction X intersects with the warp thread a, the sliding distance T1 is equal to or greater than two pitches (2×pa) of the warp thread a, and the woven fabric 21B has at least one peak m of the warp thread a within the sliding distance T1. Since tension is applied to the warp threads a by the support of the woven fabric 21 by the fabric wiping unit 20, the ink is scraped off by the peaks of the warp threads a in this manner.

[0018] FIG. 9 shows another example of woven fabric 21D. The woven fabric 21D is a highly irregular fabric having an irregular structure in a range exceeding 5 warps by 5 wefts. Such a highly irregular fabric may be used. The weave of the woven fabric 21D also satisfies the weave condition 1. Therefore, if the nozzle orifice n slides at the position of this valley va as shown in FIG. 9, the orifice n is also rubbed against the peak m, so that the ink at and around the orifice n can be sufficiently scraped off. The inkjet recording device 1 uses such highly irregular woven fabric 21D, and performs a wiping operation on the nozzle surface 11a under the control of the control unit 40 with the weft direction X as the sliding direction. In this case, the sliding direction X intersects with the warp thread a, the sliding distance T1 is equal to or greater than two pitches (2×pa) of the warp thread a, and the woven fabric 21B has at least one peak m of the warp thread a within the sliding distance T1. The sliding distance T1 is appropriately lengthened according to the weave of the fabric so that the peak m of the warp thread a rubs against any of the discharge ports n. Since tension is applied to the warp threads a by the support of the woven fabric 21 by the fabric wiping unit 20, the ink is scraped off by the peaks of the warp threads a in this manner.

[0019] The above-mentioned woven fabrics 21B-21D are used as the woven fabric 21 of the fabric wiping unit 20 of the inkjet recording device 1. In this case, there is no need to feed the fabric in the Y direction during wiping, and no matter where the sliding occurs, the crest of the warp thread a always hits the nozzle outlet n by taking the necessary sliding distance, and the ink can be sufficiently scraped off. As a result, when ink adhering to the nozzle surface 11a of the inkjet head 10 is wiped off with the woven cloth 21, the amount of ink left unwiped is reduced, improving cleaning performance.

[0020] [Various evaluation experiments] (1) Intersecting angle between the sliding direction and the warp thread The intersecting angle between the sliding direction X and the warp thread a, and the ink scraping performance from the nozzle surface 11a were evaluated as shown in the table of FIG. The crossing angle between the sliding direction X and the warp thread a is preferably within the range of 90 degrees ±15 degrees. As described above, the wiping surface 21a has high scraping performance when rubbed at an angle of 90 degrees to the warp threads a that form the ridges m. Since the scraping is performed by the warp threads a, the scraping performance decreases if the angle is shifted by 15 degrees or more.

[0021] (2) Pressing force during sliding The pressing force of nozzle surface 11a against fabric 21 during sliding, the ability to scrape ink from nozzle surface 11a, and the wear of nozzle surface 11a were evaluated as shown in the table of FIG. The pressure of the nozzle surface 11a against the woven fabric 21 during sliding is 8 to 15 gf / cm 2 It is preferable that Pressing force is 8 gf / cm 2 If the pressing force is less than 15 [gf / cm 2 ], the fibers of the woven fabric 21 will not contact the nozzle surface 11a with sufficient pressing force, and the scraping performance will decrease. 2 ], wear of the water-repellent film on the nozzle surface 11a is accelerated.

[0022] (3) Weft density The density of the weft yarns b of the woven fabric 21, the ability to scrape the ink off the nozzle surface 11a, and the ink absorbency into the woven fabric 21 were evaluated as shown in the table of FIG. The density of the weft yarns b of the woven fabric 21 is preferably in the range of 50 to 120 [number of yarns / inch]. If the density of the weft threads b is less than 50 [number of threads / inch], the number of fibers that come into contact with the nozzle surface 11a will be reduced, resulting in reduced scraping performance. On the other hand, if the density of the weft threads b exceeds 120 [number of threads / inch], the gaps between the fibers will decrease, reducing the capillary force and resulting in reduced liquid absorption.

[0023] (4) Thickness of the fabric The thickness of the woven fabric 21 and the staining of the backup member 26 were evaluated as shown in the table of FIG. The thickness of the woven fabric 21 is preferably 0.2 mm or more. If the thickness of the fabric 21 is less than 0.2 mm, the fabric 21 will not be able to absorb the ink and will stain the back-up member.

[0024] (5) Relative speed between the nozzle face and the fabric (sliding speed) The relative speed between the nozzle surface 11a and the fabric 21 during sliding, the ability to scrape off the ink from the nozzle surface 11a, and the staining of the backup member 26 were evaluated as shown in the table of FIG. The relative speed between the nozzle surface 11a and the woven fabric 21 during sliding is preferably in the range of 5 to 100 mm / s. If the relative speed (sliding speed) is less than 5 mm / s, the capillary force of the woven cloth 21 will cause too much ink to be drawn out of the nozzles of the head 10, soiling the backup member 26, while if it exceeds 100 mm / s, the speed is too fast and the scraped ink cannot be completely absorbed by the woven cloth 21, resulting in reduced scraping performance.

[0025] (6) Evaluation method The evaluation methods described above are as follows: The scraping ability was evaluated by applying a specified amount of ink to a PET film (after drying at room temperature for 5 minutes) and wiping it off once with a cloth. The sliding speed was 50 mm / s. For cases where the pressing force was not specified, the pressing force was 15 gf / cm. 2 〕. The meanings of the evaluation symbols are as follows: 〇: Completely wiped off / △: Some ink remains / ×: Clearly some ink remains

[0026] The wear was evaluated by rubbing a weighted woven fabric 21 against the nozzle surface 11a of the nozzle plate 11 used in the head 10 1000 times, and then evaluating the degree of wear of the nozzle plate 11 around the nozzle outlet. The sliding speed was 50 mm / s. The meanings of the evaluation symbols are as follows: 〇: No wear / △: Slight wear around the nozzle outlet / ×: Clear wear around the nozzle outlet

[0027] The liquid absorption was evaluated by applying a predetermined amount of ink onto a PET film, contacting the woven fabric 21 with a predetermined pressure for a predetermined time, and measuring the change in the ink weight before and after the contact as the liquid absorption rate. The meanings of the evaluation symbols are as follows: 〇: Liquid absorption rate 70% or more / △: Liquid absorption rate 40~70% / ×: Liquid absorption rate ~40%

[0028] The contamination of the backup member was evaluated by applying a predetermined amount of ink to the nozzle surface 11a of the nozzle plate 11, sandwiching a woven cloth 21 between the nozzle surface 11a and the backup member 26 and pressing it against the backup member 26. The woven cloth 21 was then removed and the surface of the backup member 26 was observed. The meanings of the evaluation symbols are as follows: ◯: No ink stains / △: Some ink stains are visible / ×: Clearly ink stains

[0029] [About yarn material and splitting application] The yarn used in the woven fabric 21 may be a polyester fiber yarn or a nylon fiber yarn. The yarn used in the woven fabric 21 may be a split yarn having a cross section as shown in Fig. 15. As shown in Fig. 15, the split yarn is a composite of two fibers S1 and S2. Nylon fiber is used as the fiber S1, and nylon fiber is used as the fiber S2. The split yarn is composed of two fibers S1 and S2 of different materials, and the fibers are split by the opening process, becoming thinner and more irregularly shaped. Therefore, the thin fiber structure improves liquid absorption, and the irregularly shaped fibers come into contact with the nozzle surface 11a, improving scraping performance. [Explanation of symbols]

[0030] 1 Inkjet recording device 10 Inkjet head 11 Nozzle plate 11a Nozzle surface 15 Inkjet head drive unit 20 Cloth Wipe Unit 21 Textile cloth 21a Wiping surface 22 Unwinding roller 23,24 Support roller 25 Winding roller 26 Backup parts 29 Cloth wipe unit drive section 35 Carriage drive unit 40 Control section 55 Recording medium transport section T1 Sliding distance X sliding direction (weft direction) a Warp b Weft m Yamabe n Nozzle outlet v Tanibe

Claims

1. an inkjet recording device comprising: an inkjet head which ejects ink from nozzles; and a cloth wiping unit having a woven cloth which wipes a nozzle face on which the ejection ports of the nozzles of the inkjet head are open, the ink adhering to the nozzle face being wiped away by relative sliding between the woven cloth and the nozzle face, The woven fabric has a structure in which a valley formed on a surface by a yarn passing from below to above or from above to below a crossing yarn is continued in a position parallel to the crossing yarn, During the sliding, the woven fabric is fed by half the pitch of the weft thread in a direction perpendicular to the sliding direction in a plan view, so that the ridges formed on the surface by the threads passing over the crossing threads of the woven fabric are rubbed against any of the ejection ports.

2. 2. The ink jet recording apparatus according to claim 1, wherein an angle between the sliding direction and warp threads of the woven fabric is within a range of 90 degrees ±15 degrees.

3. The pressure of the nozzle surface against the woven fabric during the sliding is 8 to 15 gf / cm ２ 3. The ink jet recording apparatus according to claim 1, wherein

4. 4. The ink jet recording apparatus according to claim 1, wherein the density of the weft threads of the woven fabric is in the range of 50 to 120 [threads / inch].

5. 5. The ink jet recording apparatus according to claim 1, wherein the woven fabric has a thickness of 0.2 mm or more.

6. 6. The inkjet recording apparatus according to claim 1, wherein the material of the thread used in the woven fabric is polyester or nylon.

7. 7. The inkjet recording apparatus according to claim 1, wherein the yarn used in the woven fabric is a split yarn.

8. 8. The ink jet recording apparatus according to claim 7, wherein the split yarn is made of polyester and nylon.

9. 9. The ink jet recording apparatus according to claim 1, wherein the relative speed between the nozzle surface and the fabric during the sliding movement is in the range of 5 to 100 mm / s.

10. 10. The inkjet recording apparatus according to claim 1, wherein a dimension of the woven fabric in the sliding direction exceeds a dimension obtained by adding a dimension of the nozzle plate having the nozzle surface to a distance of the sliding.

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