Printer and printing method

Abstract

To allow proper printing to be performed in a forward path and a return path, when implementing printing by making a line head reciprocate relative to a printed matter, and by scanning the line head relative to the printed matter in both directions of the forward path and the return path.SOLUTION: When implementing printing in a return path, a row of discharge ports for discharging ink last in a forward path is used as a reference, and printing of each row of discharge ports is started in an order reverse to that of the forward path from the row of discharge ports being the reference, thereby ink discharged from each row of discharge ports is superposed, and image data is mirror-reversed relative to image data of the forward path.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a printer and a printing method, and more particularly to a printer equipped with a line head and a printing method for the printer.

[0002] In this specification and the claims, "printer" includes both so-called two-dimensional printers, which eject printing ink from the nozzles of a line head toward a medium to be printed on, thereby printing a two-dimensional image on the medium, and so-called three-dimensional printers (three-dimensional modeling devices), which eject a hardening liquid such as a binder or water from the nozzles of a line head toward a powder material or the like to be printed on, thereby hardening the powder material or the like to form a three-dimensional object.

[0003] Furthermore, in this specification and the claims, the printed material includes, in the case of 2D printers, not only various recording media made of paper such as plain paper, but also various media made of various materials such as resin materials such as polyvinyl chloride (PVC) and polyethylene terephthalate (PET), textiles, cloth, aluminum, iron, and wood, and in the case of 3D printers, includes various materials such as powder materials and other powder materials that are used as raw materials for 3D objects.

[0004] Furthermore, in this specification and the claims, "ink" includes not only various types of printing ink such as solvent-based pigment ink, water-based pigment ink, water-based dye ink, and ultraviolet-curable pigment ink, but also liquids such as curing liquids used in three-dimensional modeling, and the term "ink" is intended to mean all types of liquids that are sent to a line head.

[0005] Furthermore, in this specification and the scope of the claims, the ink ejection mechanism in the line head is not particularly limited, and for example, an inkjet system can be used.

[0006] In the following, for ease of explanation, various directions will be explained using an XYZ Cartesian coordinate system; however, these directions are merely defined for ease of explanation and do not in any way limit the installation or usage of the printer and printing method according to the present invention, nor do they in any way limit the present invention. [Background technology]

[0007] As a conventional three-dimensional modeling apparatus, for example, as disclosed in JP 2017-125393 A, there is known an apparatus equipped with a line head having a plurality of ejection ports that eject ink onto a powder material serving as a printing substrate.

[0008] Such line heads are widely installed in two-dimensional printers as well as in three-dimensional modeling devices as described above.

[0009] FIG. 1 is a conceptual diagram illustrating a conventional line head.

[0010] The line head 100 is a device that ejects ink onto the printing substrate 200, and is disposed so as to be located above the printing substrate 200 in the height direction (Z direction) when the width direction of the printing substrate 200 is defined as the X direction, the longitudinal direction as the Y direction, and the height direction as the Z direction. The line head 100 is disposed fixedly relative to the printing substrate 200, while the printing substrate 200 is scanned in one direction in the Y direction (for example, forward) relative to the line head 100.

[0011] The dimension of the line head 100 in the X direction is set to be longer than the dimension of the printing substrate 200 in the X direction. A lower surface 100a of the line head 100 is provided with a plurality of ejection ports 102 that eject ink toward the printing substrate 200. The ejection ports 102 of the line head 100 are linearly arranged so as to extend along the X direction perpendicular to the Y direction, which is the scanning direction of the printing substrate 200. In the line head 100, four rows of the ejection ports 102 linearly arranged along the X direction are arranged at predetermined intervals from the front to the rear along the Y direction, which is the scanning direction. The rows are a first row 102A, a second row 102B, a third row 102C, and a fourth row 102D.

[0012] Here, the lengths in the X direction of the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D correspond to the dimension in the X direction of the printing substrate 200. Also, the interval W1 in the Y direction between the first row 102A and the second row 102B, the interval W2 in the Y direction between the second row 102B and the third row 102C, and the interval W3 in the Y direction between the third row 102C and the fourth row 102D are all set to the same interval β (interval β = interval W1 = interval W2 = interval W3), that is, to be equally spaced.

[0013] Note that when the outlets 102 are arranged linearly along the X direction, the term "linear" refers not only to a strict geometrical straight line, but also to an arrangement of points that can be regarded as an approximate straight line. For example, the outlets 102 arranged in the X direction may be shifted in the Y direction as long as the shift is approximately equal to or smaller than the pitch between the outlets 102 in the X direction.

[0014] Furthermore, the ink ejection mechanism in the line head 100 is not particularly limited, and for example, an inkjet system can be used.

[0015] In the above configuration, the fixedly arranged line head 100 moves and scans the substrate 200 in one direction in the Y direction (e.g., the forward direction), thereby ejecting ink toward the substrate 200 from the ejection ports 102 in the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D.

[0016] In this way, by providing a plurality of rows of the ejection ports 102, namely, the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D, when the line head 100 is mounted on a three-dimensional modeling device, for example, the ejection accuracy of the ink supplied by the entire line head 100 can be improved, and a modeled object with higher accuracy can be formed. Also, the amount of ink supplied in one scan can be increased, making it possible to form a more solid three-dimensional object.

[0017] Incidentally, in order to expand the above-mentioned usage of the line head 100 and improve productivity, a method has been considered in which the line head 100 is moved back and forth in the Y direction relative to the printing substrate 200, and the line head 100 is scanned in both directions in the Y direction (forward and backward in FIG. 1) relative to the printing substrate 200 for printing. By adopting such a method and scanning the printing substrate 200 in the X direction, it becomes possible to efficiently print on the printing substrate 200 having a larger area.

[0018] 2 is a conceptual diagram illustrating an example of a printer configured to scan and print the line head 100 in both directions in the Y direction (left and right in FIG. 2) relative to the printing substrate 200. Note that FIG. 2 shows the line head 100 positioned as viewed from the arrow A in FIG. 1.

[0019] In a printer 300 configured to scan and print a line head 100 in both directions in the Y direction (left and right in Figure 2) relative to a substrate 200, the line head 100 is configured to be freely movable back and forth in the left and right directions along the Y direction relative to a base member 302 extending along the Y direction.

[0020] The line head 100 performs printing by moving back and forth between an outward path moving left along the Y direction and a return path moving right along the Y direction, for example by a control device (not shown) composed of a microcomputer controlling a driving means (not shown) such as a motor in accordance with image data supplied to the control device.

[0021] A print processing operation start position marker 304 indicating the start position of a print processing operation by the line head 100 is disposed at a preset position on the base member 302. Meanwhile, a sensor 306 for detecting the print processing operation start position marker 304 is disposed at a preset position on the line head 100, for example, at the left side end portion 100L in the Y direction. Note that for the sensor 306 and the print processing operation start position marker 304, for example, a photointerrupter can be used as the sensor, and a light-shielding plate can be used as the print processing operation start position marker 304.

[0022] The rows of the outlets 102 in the line head 100 are arranged in the following order from left to right: first row 102A, second row 102B, third row 102C, and fourth row 102D.

[0023] Here, in order to facilitate understanding of the printing operation by the line head 100, the line head 100 ejects black ink (BK) from the first row 102A, ejects cyan ink (C) from the second row 102B, ejects magenta ink (M) from the third row 102C, and ejects yellow ink (Y) from the fourth row 102D. Also, the interval β is set to 11 mm.

[0024] In the printer 300, when the sensor 306 detects the print processing operation start position marker 304, the line head 100 moves a preset movement distance, an initial movement distance α (initial movement distance α is, for example, a "fixed value + minimum margin". In the printer 300, "fixed value = 16.1 mm" and "margin = 1.5 mm", so "initial movement distance α = 17.6 mm") under the control of the control device, and then starts ejecting black ink from the first row 102A. Thereafter, the line head 100 moves a further movement distance (11 mm) equivalent to the interval W1 (interval β), that is, after the line head 100 moves "initial movement distance α + 11 mm = 28.6 mm", the second row 102B starts ejecting cyan ink. After that, the line head 100 starts ejecting magenta ink from the third row 102C after it has moved a further distance (11 mm) corresponding to the interval W2 (interval β), i.e., after it has moved "initial movement distance α+11 mm+11 mm=initial movement distance α+22 mm=39.6 mm". After that, the line head 100 starts ejecting yellow ink from the fourth row 102D after it has moved a further distance (11 mm) corresponding to the interval W3 (interval β), i.e., after it has moved "initial movement distance α+11 mm+11 mm+11 mm=initial movement distance α+33 mm=50.6 mm". In this manner, the ink is ejected in order for each row of the ejection ports 102.

[0025] Here, it is assumed that image 1 data shown in Fig. 3 is supplied to the control device as image data for printing the image "<". That is, it is assumed that image 1 data consisting of BK1 data for ejecting black ink (BK) from the first row 102A, C1 data for ejecting cyan ink (C) from the second row 102B, M1 data for ejecting magenta ink (M) from the third row 102C, and Y1 data for ejecting yellow ink (Y) from the fourth row 102D is supplied to the control device as image data for forming the image "<" in which black ink (BK), cyan ink (C), magenta ink (M), and yellow ink (Y) are overlapped in four layers. The processing order of this image 1 data is "BK1 data → C1 data → M1 data → Y1 data".

[0026] 4(a), (b), (c), (d), (e), and (f) are explanatory diagrams that diagrammatically show the operation of the line head 100 on the forward path by the printer 300 shown in FIG.

[0027] That is, when the image 1 data shown in Fig. 3 is supplied to the control device, on the outward path in which the line head 100 moves leftward along the Y direction, when the sensor 306 detects the print processing operation start position marker 304 (Fig. 4(a)), the control device starts ejection of black ink from the first row 102A based on the BK1 data after the line head 100 moves leftward by the initial movement distance α, and prints with black ink on the substrate 200 (Fig. 4(b)). After that, after the line head 100 moves leftward by the "initial movement distance α+11 mm=28.6 mm", the control device starts ejection of cyan ink from the second row 102B based on the C1 data, and prints with cyan ink over the black ink printed on the substrate 200 (Fig. 4(c)). After that, the line head 100 moves leftward by "initial movement distance α+22 mm=39.6 mm", and then starts ejecting magenta ink from the third row 102C based on the M1 data, and prints the magenta ink over the cyan ink printed on the printing substrate 200 (FIG. 4(d)). After that, the line head 100 moves leftward by "initial movement distance α+33 mm=50.9 mm", and starts ejecting yellow ink from the fourth row 102D based on the Y1 data, and prints the yellow ink over the magenta ink printed on the printing substrate 200 (FIG. 4(e)).

[0028] Therefore, on the outward path in which the line head 100 described above moves leftward along the Y direction, an accurate image "<" is formed by overlapping four layers of black ink (BK), cyan ink (C), magenta ink (M) and yellow ink (Y) based on the image 1 data (Figure 4(f)).

[0029] Next, FIGS. 5(a), 5(b), 5(c), 5(d), 5(e), and 5(f) are explanatory diagrams that diagrammatically show the operation of the line head 100 in the return pass by the printer 300 shown in FIG.

[0030] That is, as in the case of the forward pass, when the image 1 data shown in FIG. 3 is supplied to the control device, in the return pass where the line head 100 moves rightward along the Y direction, when the sensor 306 detects the print processing operation start position marker 304 (FIG. 5(a)), the control device starts ejection of black ink from the first row 102A based on the BK1 data after the line head 100 moves rightward by the initial movement distance α, and prints with black ink on the substrate 200 (FIG. 5(b)). After that, after the line head 100 moves rightward by the "initial movement distance α+11 mm=28.6 mm", it starts ejection of cyan ink from the second row 102B based on the C1 data, and prints cyan ink at a position 22 mm (interval W1 (interval β)+11 mm movement distance of the line head 100=22 mm, i.e., twice the distance of the interval β) away from the black ink printed on the substrate 200 (FIG. 5(c)). After that, the line head 100 moves to the right by "initial movement distance α+22 mm=39.6 mm", and then starts ejecting magenta ink from the third row 102C based on the M1 data, and prints magenta ink at a position 22 mm (movement distance of interval W2 (interval β)+11 mm=22 mm, i.e., twice the distance of interval β) away from the cyan ink printed on the printing substrate 200 (FIG. 5(d)). After that, the line head 100 moves to the right by "initial movement distance α+33 mm=50.9 mm", and then starts ejecting yellow ink from the fourth row 102D based on the Y1 data, and prints yellow ink at a position 22 mm (movement distance of interval W3 (interval β)+11 mm=22 mm, i.e., twice the distance of interval β) away from the magenta ink printed on the printing substrate 200 (FIG. 5(d)).

[0031] For this reason, on the return path in which the above-mentioned line head 100 moves to the right along the Y direction, it is not possible to print four layers of black ink (BK), cyan ink (C), magenta ink (M) and yellow ink (Y) based on the image 1 data, and the printed image becomes a mirror-inverted image ">", meaning that an accurate image "<" cannot be formed. [Prior art documents] [Patent documents]

[0032] [Patent Document 1] JP 2017-125393 A Summary of the Invention [Problem to be solved by the invention]

[0033] The present invention has been made in consideration of the above-mentioned problems with the conventional technology, and has as its object to provide a printer and printing method which enables appropriate printing on both the forward and return paths when the line head is moved back and forth relative to the substrate to print by scanning the line head in both forward and return paths across the substrate, thereby expanding the usage patterns of the line head and improving productivity. [Means for solving the problem]

[0034] In order to achieve the above object, the printer and printing method of the present invention, when printing on the return pass, uses the row of nozzles that ejects ink latest on the forward pass as a reference, and starts printing of each row of nozzles from this reference row of nozzles in the reverse order to the forward pass, so that the ink ejected from each row of nozzles overlaps and the image data is mirror-inverted with respect to the image data on the forward pass.

[0035] Therefore, the printer and printing method according to the present invention can perform proper printing on both the forward and return passes.

[0036] That is, the printer according to the present invention comprises a line head which has a plurality of rows of ejection ports arranged at preset intervals, and which moves back and forth in a direction perpendicular to the direction in which the rows extend, ejecting ink in sequence from each row of ejection ports in accordance with image data supplied as a print target, and a line head ejection control device which controls, when the line head ejects the ink from the ejection ports on the return path, to eject the ink from each row of ejection ports in the plurality of rows in the reverse order to the outgoing path from the row of ejection ports which ejects the ink latest on the outgoing path as a reference. The ink jet head has a forward reversing means, and an image data conversion means for adding null data to the image data supplied as the printing target to convert the image data into image data in which the ink ejected from each row of the multiple rows of nozzles overlaps, and for converting the image data supplied as the printing target into image data that is a mirror image of the image data of the outward pass, and when the line head ejects the ink from the nozzles on the return pass, ink is ejected from the nozzles based on control by the line head ejection order reversing means in accordance with the image data converted by the image data conversion means.

[0037] In addition, the printer of the present invention is the printer of the present invention described above, which has an outbound printing process operation start position marker indicating the start position of the printing process operation by the line head on the outbound pass, a return printing process operation start position marker indicating the start position of the printing process operation by the line head on the return pass, and a sensor provided on the line head for detecting the outbound printing process operation start position marker and the return printing process operation start position marker, and when the marker detects the outbound printing process operation start position marker or the return printing process operation start position marker, it moves a predetermined distance and then starts printing process.

[0038] Furthermore, the printer according to the present invention is the printer according to the present invention described above, wherein the intervals between the plurality of rows are equal, and the line head ejects ink in sequence from each row of the ejection openings each time it moves by the interval.

[0039] Furthermore, the printer according to the present invention is the printer according to the present invention described above, wherein the multiple rows are a first row that ejects black ink, a second row that ejects cyan ink, a third row that ejects magenta ink, and a fourth row that ejects yellow ink, and on the forward pass, ink is ejected row by row in the order of the first row, the second row, the third row, and the fourth row, and on the return pass, ink is ejected row by row in the order of the fourth row, the third row, the second row, and the first row.

[0040] Furthermore, a printing method according to the present invention is a printing method which includes a plurality of rows of nozzles arranged at predetermined intervals, and which uses a line head which moves back and forth in a direction perpendicular to the direction in which the rows extend to eject ink from each row of the nozzles in sequence in accordance with image data supplied as the object to be printed, and which adds null data to the image data supplied as the object to be printed to convert it into image data in which ink ejected from the plurality of rows of nozzles in each row overlaps, and converts the image data supplied as the object to be printed into image data which is a mirror image of the image data in the forward pass, and when the line head ejects the ink from the nozzles on the return pass, the ink is ejected from the plurality of rows of nozzles in sequence in accordance with the converted image data, from the row of the nozzles which ejects the ink latest on the forward pass as a reference, in the reverse order to the forward pass, from the reference row of the nozzles.

[0041] Furthermore, the printing method according to the present invention is the printing method according to the present invention described above, wherein the intervals between the plurality of rows are equal, and ink is ejected in sequence from each row of the ejection ports each time the nozzles move by the interval. Effect of the Invention

[0042] Since the present invention is configured as described above, when the line head is moved back and forth relative to the substrate and scanned in both directions, forward and backward, to print across the substrate, it is possible to perform appropriate printing on the forward and backward paths, thereby achieving the excellent effect of expanding the usage patterns of the line head and improving productivity. [Brief description of the drawings]

[0043] [Figure 1] FIG. 1 is a conceptual diagram illustrating a conventional line head. [Diagram 2] Fig. 2 is a conceptual diagram illustrating an example of a printer configured to scan a line head in both directions in the Y direction to print on a substrate. Fig. 2 shows the line head positioned as viewed from the arrow A in Fig. 1. [Diagram 3] FIG. 3 is an explanatory diagram showing image 1 data as an example of image data. [Figure 4] 4(a), (b), (c), (d), (e), and (f) are explanatory diagrams that diagrammatically show the operation of the line head on the forward pass by the printer shown in FIG. [Diagram 5] 5(a), (b), (c), (d), (e), and (f) are explanatory diagrams that diagrammatically show the operation of the line head on the return pass by the printer shown in FIG. [Figure 6] FIG. 6 is a schematic perspective view illustrating a printer according to an embodiment of the present invention. [Figure 7]Figures 7(a), (b), and (c) are explanatory diagrams that show a schematic representation of the main parts of the printer shown in Figure 6. More specifically, Figure 7(a) is an explanatory diagram seen from the arrow B in Figure 6 that shows a schematic representation of the positional relationship between a forward pass print processing operation start position marker that indicates the start position of a print processing operation by the line head on the forward pass and a backward pass print processing operation start position marker that indicates the start position of a print processing operation by the line head on the backward pass, and a sensor. Figure 7(b) is an explanatory diagram seen from the arrow C in Figure 7(a). Figure 7(c) is an explanatory diagram of a photointerrupter used as a sensor. [Figure 8] FIG. 8 is an explanatory diagram showing an example of various dimensions related to the reciprocating motion of the line head in the printer shown in FIG. [Figure 9] FIG. 9 is a block diagram showing the functional configuration of the control device in the printer shown in FIG. 6, which is related to the implementation of the present invention. [Figure 10] 10(a), (b), (c), (d), (e), and (f) are explanatory diagrams that diagrammatically show the operation of the line head on the forward pass by the printer shown in FIG. [Figure 11] 11(a), (b), and (c) are explanatory diagrams that show a schematic relationship between the operation of the line head and image data at the start of printing on the return pass by the printer shown in FIG. [Figure 12] 12(a), 12(b), 12(c), 12(d), 12(e), and 12(f) are explanatory diagrams that show the print results on the return pass by the printer shown in FIG. [Figure 13] 13(a), 13(b), and 13(c) are explanatory diagrams that show a schematic relationship between the operation of the line head and image data when printing is completed on the return pass by the printer shown in FIG. [Figure 14] FIG. 14 is an explanatory diagram showing another example of the positional relationship between the forward print processing operation start position marker and the return print processing operation start position marker and the sensor. [Figure 15] FIG. 15 is an explanatory diagram showing another example of the positional relationship between the forward pass print processing operation start position marker and the backward pass print processing operation start position marker and the sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a printer and a printing method according to the present invention will be described in detail below with reference to the accompanying drawings.

[0045] In the following description, the components that are the same as or equivalent to those described with reference to Figures 1 to 5 will be denoted by the same reference symbols as those used in the description with reference to Figures 1 to 5, and descriptions of their configurations and functions will be omitted as appropriate.

[0046] (I) Description of the configuration of a printer according to an embodiment of the present invention FIG. 6 is a schematic perspective view illustrating a printer 10 according to an embodiment of the present invention.

[0047] That is, a printer 10 according to an embodiment of the present invention includes a fixed base member 14 arranged to extend along the Y direction on a base unit 12 which is a fixed member, a line head 100 arranged to be movable back and forth in the left and right direction along the Y direction relative to the base member 14, an X-rail 16 arranged to extend along the X direction on the base unit 12, a print substrate placement table 18 that is movable back and forth in the X direction on the X-rail 16, and a control device 20 that comprehensively controls the operation of each part of the printer 10. A print substrate 200 is placed on the print substrate placement table 18 and scanned along the X direction. The first row 102A, second row 102B, third row 102C, and fourth row 102D of the outlets 102 in the line head 100 are arranged at intervals β from left to right in the order of the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D.

[0048] In addition, the configuration in which the line head 100 can be freely moved back and forth along the Y direction relative to the base member 14, and the configuration in which the printing substrate placing table 18 can be freely moved back and forth on the X rail 16 can be realized by controlling a driving means such as a motor (not shown) with the control device 20. Since these technologies are conventionally known technologies disclosed in the above-mentioned JP 2017-125393 A and the like, detailed explanations thereof will be omitted.

[0049] At a predetermined location on the base member 14, for example, at the right side portion 14R in the Y direction, an outbound printing operation start position marker 22 is arranged, indicating the start position of the printing operation by the line head 100 on the outbound path (the path along which the line head 100 moves leftward in the Y direction), and at the left side portion 14L in the Y direction, a return printing operation start position marker 24 is arranged, indicating the start position of the printing operation by the line head 100 on the return path (the path along which the line head 100 moves rightward in the Y direction).

[0050] On the other hand, a sensor 306 for detecting the forward print process operation start position marker 22 and the return print process operation start position marker 24 is disposed at a preset position of the line head 100, for example, at the left end portion 100L in the Y direction.

[0051] 7(a), (b), and (c), the sensor 306 and the forward print processing operation start position marker 22 and the return print processing operation start position marker 24 may be, for example, a photointerrupter having a light-emitting portion 306a and a light-receiving portion 306b as the sensor 306, and a light-shielding plate may be used as the forward print processing operation start position marker 22 and the return print processing operation start position marker 24. In this case, when the forward print processing operation start position marker 22 or the return print processing operation start position marker 24 functioning as the light-shielding plate comes between the light-emitting portion 306a and the light-receiving portion 306b of the sensor 306 functioning as a photointerrupter, the light-receiving portion 306b cannot receive light emitted from the light-emitting portion 306a, and the sensor 306 detects the forward print processing operation start position marker 22 or the return print processing operation start position marker 24.

[0052] Fig. 8 is an explanatory diagram showing an example of various dimensions related to the reciprocating movement of the line head 100 in the printer 10 shown in Fig. 6. As described in the "Background Art" section, the various dimensions related to the line head 100 include the intervals W1, W2, and W3, i.e., the interval β, which is 11 mm, and when the initial movement distance α when the sensor 306 detects the forward print processing operation start position marker 22 or the return print processing operation start position marker 24 is 17.6 mm, it is preferable to set the dimensions as shown in the example in Fig. 8.

[0053] (II) Description of the functional configuration related to the implementation of the present invention of a control device in a printer according to an embodiment of the present invention The control device 20 comprehensively controls the operation of each part of the printer 10 as described above, but the configuration is not particularly limited. The control device 20 is configured by, for example, a microcomputer. The hardware configuration of the microcomputer is also not particularly limited, but for example, it includes an interface (I / F) that receives image data and the like from an external device such as a host computer, a central processing unit (CPU) that executes instructions of a control program, a read only memory (ROM) that stores the program executed by the CPU, a random access memory (RAM) used as a working area for expanding the program, and a storage unit that stores various data such as the control program described above.

[0054] Here, Figure 9 shows a block diagram illustrating the functional configuration related to the implementation of the present invention of the control device 20 in the printer 10 shown in Figure 6, and the control device 20 has a line head ejection order reversal unit 20a and an image data conversion unit 20b.

[0055] The line head ejection order reversal unit 20a controls the line head 100 so that, when the line head 100 prints on the return pass, it uses the fourth row 102D, which is the row of ejection ports that ejects ink latest on the forward pass, as a reference and starts printing of each row of ejection ports from this reference fourth row 102D in the reverse order of the forward pass, i.e., in the order of "fourth row 102D → third row 102C → second row 102B → first row 102A."

[0056] The image data conversion unit 20b is configured to include an adjustment unit 20b-1 and a mirror inversion unit 20b-2, and converts image data supplied as the print target into image data to be used for printing on the return pass.

[0057] When the line head 100 prints on the return pass, the adjustment unit 20b-1 starts ejecting yellow ink (Y) from the fourth column 102D at a position that is a further distance β×6=66 mm from the position of the first column 102A when the sensor 306 detects the forward pass printing process operation start position marker 22 and moves the initial movement distance α, and adds null data to the beginning of the image data so that the yellow ink (Y) ejected from the fourth column 102D, the magenta ink (M) ejected from the third column, the cyan ink (C) ejected from the second column, and the black ink (BK) ejected from the first column overlap, and adjusts the processing order of each column of ejection ports after the null data is finished to be reversed from the processing order on the forward pass (see Figure 11(b)).

[0058] The mirror inversion unit 20b-2 processes the image based on the image data supplied to the control device 20 as the print target so as to produce a mirror inverted image (see FIG. 11(c)).

[0059] (III) Description of the operation of a printer and a printing method according to an embodiment of the present invention In the printer 10 configured as described above, under the control of the control device 20, ink is ejected from the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D of the nozzles of the line head 100 to perform a printing process on the substrate 200.

[0060] Here, the line head 100 ejects black ink (BK) from the first row 102A, ejects cyan ink (C) from the second row 102B, ejects magenta ink (M) from the third row 102C, and ejects yellow ink (Y) from the fourth row 102D, as explained in the "Background Art" section. Also, the intervals W1, W2, and W3, i.e., the interval β, are set to 11 mm, as explained in the "Background Art" section.

[0061] In the printer 10, when printing on the forward pass in which the line head 100 moves to the left, when the sensor 306 detects the forward pass print processing operation start position marker 22, the line head 100 moves to the left a preset movement distance, an initial movement distance α (initial movement distance α is, for example, a fixed value + minimum margin. In the printer 300, the fixed value = 16.1 mm and the margin = 1.5 mm, therefore, the initial movement distance α = 17.6 mm), under the control of the control device 20, in the same way as when the sensor 306 detects the print processing operation start position marker 304 described in the "Background Art" section, and then begins ejecting black ink from the first row 102A. After that, the line head 100 moves further to the left by a movement distance (11 mm) corresponding to the interval W1 (interval β), i.e., after the line head 100 moves left by "initial movement distance α+11 mm=28.6 mm", the second row 102B starts ejecting cyan ink. After that, the line head 100 moves further to the left by a movement distance (11 mm) corresponding to the interval W2 (interval β), i.e., after the line head 100 moves left by "initial movement distance α+11 mm+11 mm=initial movement distance α+22 mm=39.6 mm", the third row 102C starts ejecting magenta ink. After that, the line head 100 moves further to the left by a movement distance (11 mm) corresponding to the interval W3 (interval β), that is, after the line head 100 moves left by the "initial movement distance α+11 mm+11 mm+11 mm=initial movement distance α+33 mm=50.6 mm", the ink is controlled to be ejected in sequence from each row of the ejection ports 102 so that the ejection of yellow ink from the fourth row 102D begins.

[0062] 10(a), (b), (c), (d), (e), and (f) are explanatory diagrams that diagrammatically show the operation of the line head 100 on the forward path of the printer 10 shown in FIG.

[0063] That is, when the image 1 data shown in Fig. 3 is supplied to the control device 20, in the forward pass where the line head 100 moves leftward along the Y direction, when the sensor 306 detects the forward pass print processing operation start position marker 22 (Fig. 10(a)), the control device 20 starts ejecting black ink from the first row 102A based on the BK1 data after the line head 100 moves leftward by the initial movement distance α, as explained in the "Background Art" section, and prints black ink on the printing substrate 200 (Fig. 10(b)). After that, the line head 100 moves leftward by the "initial movement distance α+11 mm=28.6 mm", and starts ejecting cyan ink from the second row 102B based on the C1 data, and prints cyan ink over the black ink printed on the printing substrate 200 (Fig. 10(c)). After that, the line head 100 moves leftward by "initial movement distance α+22 mm=39.6 mm", and then starts ejecting magenta ink from the third row 102C based on the M1 data, and prints the magenta ink over the cyan ink printed on the printing substrate 200 (FIG. 10(d)). After that, the line head 100 moves leftward by "initial movement distance α+33 mm=50.9 mm", and starts ejecting yellow ink from the fourth row 102D based on the Y1 data, and prints the yellow ink over the magenta ink printed on the printing substrate 200 (FIG. 10(e)).

[0064] For this reason, in the printer 10, on the outward path in which the above-mentioned line head 100 moves leftward along the Y direction, an accurate image "<" is formed by overlapping four layers of black ink (BK), cyan ink (C), magenta ink (M) and yellow ink (Y) based on the image 1 data, in the same manner as described in the "Background Art" section (Figure 10(f)).

[0065] Next, in the printer 10, when printing on the return pass in which the line head 100 moves to the right, the line head ejection order reversal unit 20a of the control device 20 controls the fourth row 102D, which is the row of ejection ports that ejects ink latest on the forward pass, to start printing for each row of ejection ports 102, by ejecting ink from each row of ejection ports 102 in the reverse order from the forward pass, i.e., "fourth row 102D → third row 102C → second row 102B → first row 102A," based on the fourth row 102D used as the reference.

[0066] The image data is converted by the image data conversion unit 20b as shown in Fig. 11(b) and (c). That is, when the line head 100 prints on the return path, the adjustment unit 20b-1 of the image data conversion unit 20b starts ejection of yellow ink (Y) from the fourth row 102D at a position that is further away from the position of the first row 102A by "the interval β×6=66 mm" from the position at which the sensor 306 detects the forward print processing operation start position marker 22 and moves by the initial movement distance α, and adds null data to the beginning of the image data so that the yellow ink (Y) ejected from the fourth row 102D, the magenta ink (M) ejected from the third row, the cyan ink (C) ejected from the second row, and the black ink (BK) ejected from the first row overlap, and adjusts the processing order of each row of ejection ports after the null data ends to be the opposite to the processing order on the forward path (see Fig. 11(b)). Furthermore, the image based on the image data supplied to the control device 20 as the print target is converted into a mirror-inverted image by the mirror inversion section 20b-2 of the image data conversion section 20b (see FIG. 11(c)).

[0067] Specifically, in the printer 10, when printing on the return pass in which the line head 100 moves to the right, when the sensor 306 detects the return pass print processing operation start position marker 24 ((Figure 11(a)(a-1)), the line head 100 moves to the right by a preset movement distance, an initial movement distance α (initial movement distance α is, for example, a fixed value + minimum margin. In the printer 300, it is assumed that "fixed value = 16.1 mm" and "margin = 1.5 mm", and therefore "initial movement distance α = 17.6 mm"), and then, since the image data is null data, the first column 102A does not eject black ink (BK) ((Figure 11(a)(a-2)). After that, the line head 100 moves to the right a distance (11 mm) corresponding to the interval β, and then the second row 102B does not eject cyan ink (C) as the image data is null data (Figure 11(a)(a-3)). After that, the line head 100 moves to the right a distance (11 mm) corresponding to the interval β, and then the third row 102C does not eject magenta ink (M) as the image data is null data (Figure 11(a)(a-4)). After that, the line head 100 moves to the right a distance (11 mm) corresponding to the interval β, and then the image data is not null data, and then the fourth row 102D begins ejecting yellow ink (Y) (Figure 11(a)(a-5)).

[0068] In other words, as shown in FIG. 12(b), after the sensor 306 detects the return print processing operation start position marker 24 (FIG. 12(a)), when the line head 100 moves "17.6 mm + 11 mm + 11 mm + 11 m = 50.6 mm," that is, when the fourth row 102D is at a position "distance β x 6 = 66 mm" away from the position of the first row 102A when it moves the initial movement distance α, the ejection of yellow ink (Y) begins and printing begins.

[0069] Next, after the line head 100 moves to the right a distance (11 mm) equivalent to the interval β, the image data is not null data, so it begins ejecting magenta ink (M) from the third row 102C ((Figure 11(a)(a-6)). In other words, when the line head 100 moves "50.6 mm + 11 mm = 61.6 mm," it begins ejecting magenta ink (M) and performs printing (Figure 12(c)).

[0070] Next, after the line head 100 moves to the right a distance (11 mm) equivalent to the interval β, the image data is not null data, so the ejection of cyan ink (C) begins from the second row 102B ((Figure 11(a)(a-7)). In other words, when the line head 100 moves "61.6 mm + 11 mm = 72.6 mm," the ejection of cyan ink (C) begins and printing begins (Figure 12(d)).

[0071] Next, after the line head 100 moves a distance (11 mm) equivalent to the interval β to the right, since the image data is not null data, it starts ejecting black ink (BK) from the first row 102A ((Figure 11(a)(a-8)). In other words, when the line head 100 moves 72.6 mm + 11 mm = 83.6 mm, it starts ejecting black ink (BK) and starts printing (Figure 12(e)).

[0072] Therefore, in the printer 10, even on the return path in which the line head 100 moves to the right along the Y direction, an accurate image "<" can be formed by overlapping four layers of yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (BK) based on the image data (Figure 12 (f)).

[0073] Here, Figures 13(a), (b), and (c) are explanatory diagrams that show a schematic relationship between the operation of the line head and image data at the end of printing on the return pass by the printer shown in Figure 6. Note that Figures 13(a) and (b) are the image data shown in Figures 11(b) and (c), respectively.

[0074] When printing is to be completed, first, the reading of image data for the fourth row 102D is completed, the ejection of yellow ink is completed, and printing by the fourth row 102D is completed (FIG. 13(c)(c-1)). After that, the line head 100 moves to the right by a movement distance (11 mm) corresponding to the interval β, after which the reading of image data for the third row 102C is completed, the ejection of magenta ink is completed, and printing by the third row 102C is completed (FIG. 13(c)(c-2)). After that, the line head 100 moves to the right by a movement distance (11 mm) corresponding to the interval β, the reading of image data for the second row 102B is completed, the ejection of cyan ink is completed, and printing by the second row 102B is completed (FIG. 13(c)(c-3)). After that, the line head 100 moves to the right a distance (11 mm) corresponding to the interval β, then completes reading of the image data for the first row 102A, stops ejecting black ink, and ends printing by the first row 102A (Figure 13 (c) (c-4)).

[0075] (IV) Description of the effects of the printer and printing method according to an embodiment of the present invention As described above, according to the printer 10 and printing method of an embodiment of the present invention, when the line head 100 prints on its return pass, it is possible to print an accurate image with four layers of black ink (BK), cyan ink (C), magenta ink (M), and yellow ink (Y) using the image data used on the forward pass, just as when the line head 100 prints on its forward pass.

[0076] (V) Description of other embodiments and modifications The above-described embodiment is merely an example, and the present invention can be embodied in various other forms. In other words, the present invention is not limited to the above-described embodiment, and various omissions, substitutions, modifications, etc. can be made without departing from the gist of the present invention.

[0077] For example, the above-described embodiment may be modified as shown in the following (V-1) to (V-6).

[0078] (V-1) In the above embodiment, a photointerrupter is provided as the sensor 306, but it goes without saying that the sensor 306 is not limited to this. The sensor 306 may have any configuration as long as it can detect the forward print processing operation start position marker 22 and the return print processing operation start position marker 24. For example, the sensor 306 may be an optical sensor other than a photointerrupter (e.g., a reflective optical sensor), a magnetic sensor, or a touch sensor that reacts when it comes into contact with the forward print processing operation start position marker 22 and the return print processing operation start position marker 24.

[0079] (V-2) In the above embodiment, the forward print processing operation start position marker 22 and the return print processing operation start position marker 24 are configured as separate entities, but this is of course not limited to this and the two may be connected. Furthermore, the forward print processing operation start position marker 22 and the return print processing operation start position marker 24 may be configured in any manner as long as they can be detected by the sensor 306.

[0080] (V-3) In the above embodiment, four rows of the ejection ports 102, namely, the first row 102A, the second row 102B, the third row 102C, and the fourth row 102D, are provided, but it goes without saying that the number of rows of the ejection ports 102 is not limited to four. There may be two or more rows of the ejection ports 102.

[0081] (V-4) In the above embodiment, black ink is ejected from the first row 102A, cyan ink is ejected from the second row 102B, magenta ink is ejected from the third row 102C, and fourth row 102D, but it is of course not limited to this, and the type and color of ink ejected from the rows of ejection openings are not limited.

[0082] (V-5) In the above embodiment, the forward print process start position marker 22 is disposed at the right side portion 14R of the base member 14, the backward print process start position marker 24 is disposed at the left side portion 14L of the base member 14, and the sensor 306 is disposed at the left end portion 100L of the line head 100. However, the arrangement of the forward print process start position marker 22, the backward print process start position marker 24, and the sensor 306 is not limited to this. For example, as shown in Fig. 14, the sensor 306 may be provided at the center of the line head 100 in the Y direction, or as shown in Fig. 15, the sensor 306 may be provided at a position protruding from the line head 100 in the Y direction.

[0083] (V-6) The above-described embodiment and the various other embodiments and modifications shown in (V-1) to (V-5) may of course be combined as appropriate. [Industrial Applicability]

[0084] The present invention can be used in so-called two-dimensional printers, which eject printing ink toward a medium to print a two-dimensional image on the medium, and in so-called three-dimensional printers (three-dimensional modeling devices), which eject a hardening liquid such as a binder or water toward a powder material, hardening the powder material, and forming a three-dimensional object. [Explanation of symbols]

[0085] 10 Printers 12 Base 14 Base material 14R Right side part 14L left side part 16 x Rails 18 Printing material placement table 20 Control device 20a Line head ejection order reversing unit (line head ejection order reversing means) 20b Image data conversion unit (image data conversion means) 20b-1 Adjustment unit (image data conversion means) 20b-2 Mirror inversion unit (image data conversion means) 22 Forward print processing operation start position marker 24 Return pass print processing operation start position marker 100 Line Head 100a bottom side 102 Discharge port 102A 1st row 102B 2nd row 102C 3rd row 102D 4th row 100L left side end 200 Printing material 300 Printers 302 Base material 304 Print processing operation start position marker 306 Sensor 306a Light emitting part 306b Light receiving part

Claims

1. a line head including a plurality of rows of ejection ports arranged at predetermined intervals, the line head moving back and forth in a direction perpendicular to the direction in which the rows extend, and ejecting ink in sequence from each row of ejection ports in accordance with image data supplied as an object to be printed; a line head ejection order reversing means for controlling, when the line head ejects the ink from the ejection openings on the return pass, to eject the ink from the ejection openings of the plurality of rows for each row in a reverse order to the forward pass from the row of the ejection openings that ejects the ink latest on the forward pass; an image data conversion means for converting the image data supplied as the object to be printed into image data in which inks ejected from the ejection openings in each of the plurality of rows overlap by adding null data to the image data supplied as the object to be printed, and for converting the image data supplied as the object to be printed into image data that is mirror-inverted with respect to the image data of the outward pass; having When the line head ejects the ink from the ejection openings during the return pass, the ink is ejected from the ejection openings under the control of the line head ejection order reversing means in accordance with the image data converted by the image data conversion means. A printer characterized by:

2. 2. The printer according to claim 1, a forward pass print processing operation start position marker indicating a start position of a print processing operation by the line head in the forward pass; a return pass print processing operation start position marker indicating a start position of a print processing operation by the line head in the return pass; a sensor provided on the line head for detecting the forward print processing operation start position marker and the return print processing operation start position marker; having When the marker detects the forward print processing operation start position marker or the return print processing operation start position marker, the marker moves a preset distance and then starts the print processing. A printer characterized by:

3. 3. The printer according to claim 1, the spacing between the rows is equal; The line head ejects ink in sequence for each row of the ejection openings every time the line head moves by the interval. A printer characterized by:

4. 4. The printer according to claim 3, the plurality of rows are a first row for ejecting black ink, a second row for ejecting cyan ink, a third row for ejecting magenta ink, and a fourth row for ejecting yellow ink; In the forward pass, ink is ejected for each row in the order of the first row, the second row, the third row, and the fourth row; In the return pass, ink is ejected for each row in the order of the fourth row, the third row, the second row, and the first row. A printer characterized by:

5. A printing method comprising: a line head having a plurality of rows of ejection ports arranged at predetermined intervals, the line head moving back and forth in a direction perpendicular to a direction in which the rows extend; and ejecting ink in sequence from each of the rows of ejection ports in accordance with image data supplied as a print target, the method comprising: adding null data to the image data supplied as the object to be printed, converting the image data into image data in which ink ejected from the ejection openings of the plurality of rows overlaps, and converting the image data supplied as the object to be printed into image data that is mirror-inverted with respect to the image data of the outward pass; When the line head ejects the ink from the ejection openings on the return path, the ink is ejected from the ejection openings of the plurality of rows for each row according to the converted image data, in a reverse order to the outgoing path, starting from the row of ejection openings that is the reference, based on the row of ejection openings that ejects the ink latest on the outgoing path. A printing method comprising:

6. 6. The printing method according to claim 5, the spacing between the rows is equal; Each time the nozzle moves by the distance, ink is ejected from each row of the ejection openings in order. A printing method comprising:

Images