Printing device and method

Abstract

To provide a printing device and a method that can suppress adverse effect on a printing image due to irregularities of a surface of cardboard.SOLUTION: A printing device controls an amount of ink to be discharged from line heads 21-24 on the basis of the line heads 21-24 for discharging ink to cardboard P having a corrugated flute F as an inner core and a correction waveform with a waveform having the same phase or an opposite phase to the flute F.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printing apparatus and method for printing on corrugated board. [Background technology]

[0002] 2. Description of the Related Art Printing devices have been proposed that eject ink onto cardboard to print barcodes and the like.

[0003] For example, Patent Document 1 proposes a printing device that uses an inkjet method to print multi-level barcodes on cardboard for packaging photosensitive materials. Patent Document 1 also proposes printing using hot melt ink to prevent misreading of the barcode and ensure consistent printing accuracy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-293857 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, cardboard is composed of paper (liner) on the front and back and wavy paper (flute) in the center. Due to this configuration, the corrugated shape of the flutes affects the surface of the cardboard, making it uneven. For this reason, when direct printing is performed by directly ejecting ink onto the cardboard using an inkjet head, the ink penetration rate and head gap differ depending on the unevenness, and unintended bleeding occurs in the printed image. In particular, the printed image printed on the cardboard often contains code information such as barcodes and QR codes (registered trademark) for management purposes, and bleeding has a significant adverse effect.

[0006] In Patent Document 1, in order to solve the problem of reduced printing accuracy caused by unevenness on the surface of the cardboard, hot melt ink is used, but there is a problem that the inkjet head and ink are limited.

[0007] In view of the above circumstances, an object of the present invention is to provide a printing device and method that can suppress the adverse effects on printed images caused by unevenness on the surface of cardboard. [Means for solving the problem]

[0008] The printing device of the present invention is a printing device comprising an ejection section that ejects ink onto cardboard having a corrugated flute as a center core, and a control section that controls the amount of ink ejected from the ejection section based on a correction waveform having a waveform that is in phase or opposite phase with the flutes. Effect of the Invention

[0009] According to the printing device of the present invention, the amount of ink ejected from the ejection section is controlled based on a correction waveform having a waveform that is in phase or opposite phase to the flute, thereby suppressing the adverse effects on the printed image caused by unevenness on the surface of the cardboard. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an external perspective view of an inkjet printing apparatus using an embodiment of a printing apparatus according to the present invention; [Diagram 2] Top view of the head unit [Diagram 3] FIG. 2 is a block diagram showing a control system of the inkjet printing apparatus shown in FIG. [Figure 4] FIG. 13 is a diagram for explaining ink ejection control based on a correction waveform when the direction in which the concaves and convexes of the flute continue is parallel to the transport direction; [Diagram 5] A diagram showing a case where the direction in which the flutes are continuous is perpendicular to the conveying direction of the cardboard. [Figure 6]FIG. 13 is a diagram for explaining ink ejection control based on a correction waveform when the direction in which the concaves and convexes of the flutes continue is perpendicular to the transport direction; [Figure 7] FIG. 13 is a diagram showing an example of a table showing the relationship between the type of flute and the correction waveform. [Figure 8] FIG. 1 shows an example of an ideal flute shape, a deformed flute shape, and a correction waveform generated based on the deformed flute shape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An inkjet printing apparatus 1 using one embodiment of a printing apparatus of the present invention will be described in detail below with reference to the drawings. The inkjet printing apparatus 1 of this embodiment performs a printing process on cardboard and is characterized by controlling the ink discharge onto the cardboard, but first, the overall configuration of the inkjet printing apparatus 1 will be described with reference to Fig. 1. Fig. 1 is an external perspective view showing a schematic configuration of the inkjet printing apparatus 1 of this embodiment. The up, down, left, right, front, and back directions shown in Fig. 1 are the up, down, left, right, front, and back directions of the inkjet printing apparatus 1 of this embodiment.

[0012] The inkjet printing device 1 of this embodiment ejects ink onto the surface of a liner L of a corrugated cardboard P having wave-shaped flutes F as a core, thereby performing printing. As shown in Fig. 1, the inkjet printing device 1 includes a transport unit 10 and a head unit 20. In this embodiment, the transport unit 10 corresponds to the transport section of the present invention, and an inkjet head 25 of the head unit 20, which will be described later, corresponds to the ejection section of the present invention.

[0013] The conveying unit 10 conveys the cardboard P in the direction of the arrow Y1 (conveying direction) shown in Fig. 1. In this embodiment, as shown in Fig. 1, a case will be described in which the direction in which the concaves and convexes of the flutes F of the cardboard P continue (the direction of the arrow Y2 shown in Fig. 1) is the same as the conveying direction of the cardboard P.

[0014] The conveying unit 10 includes two platen rollers 11 and 12 extending in a direction perpendicular to the conveying direction of the cardboard P, a conveying belt 13, and the like.

[0015] The two platen rollers 11, 12 are arranged parallel to and spaced apart in the conveying direction of the cardboard P. A circular conveyor belt 13 is stretched between the two parallel arranged platen rollers 11, 12, and the circular conveyor belt 13 moves as the platen rollers 11, 12 rotate, thereby conveying the cardboard P.

[0016] The head unit 20 is provided above the transport unit 10, and prints by ejecting ink onto the surface of the liner L of the cardboard P transported by the transport unit 10. Examples of the printed image printed by the head unit 20 include code information such as a barcode or QR code, and image information such as product photos or illustrations.

[0017] 1, the head unit 20 has four line heads 21, 22, 23, and 24. In this embodiment, the line head 21 ejects K (black) ink, the line head 22 ejects C (cyan) ink, the line head 23 ejects M (magenta) ink, and the line head 24 ejects Y (yellow) ink.

[0018] 2 is a diagram of the head unit 20 viewed from above. The four line heads 21-24 are arranged in parallel at predetermined intervals in the transport direction. Each of the line heads 21-24 is formed by arranging a plurality of inkjet heads 25 in a direction perpendicular to the transport direction.

[0019] As shown in Fig. 2, each of the line heads 21 to 24 in this embodiment includes six inkjet heads 25. In the inkjet heads 25, a plurality of nozzles that eject ink are arranged in the direction of the arrow X shown in Fig. 1 (a direction perpendicular to the conveying direction of the cardboard P).

[0020] In each of the line heads 21 to 24, the six inkjet heads 25 are arranged in a staggered manner in a direction perpendicular to the conveying direction. As the cardboard P is conveyed, ink is ejected from the six staggered inkjet heads 25 at preset ejection timings, thereby printing on the cardboard P.

[0021] 3 is a block diagram showing a control system of the inkjet printing apparatus 1 of this embodiment. The inkjet printing apparatus 1 includes a control unit 30 that controls the entire apparatus.

[0022] The control unit 30 includes a CPU (Central Processing Unit), a semiconductor memory, a hard disk, etc. The control unit 30 executes a program stored in advance in a storage medium such as the semiconductor memory or the hard disk, and controls the transport unit 10 and the head unit 20 by operating an electric circuit.

[0023] In particular, the control unit 30 of this embodiment controls the amount of ink ejected from each inkjet head 25 based on a correction waveform having a waveform in phase with the flutes F of the cardboard P. Specifically, where the waves of the flutes F are highest, the flutes F become convex parts and overlap with the surface paper (liner L), so ink is less likely to bleed even if a large amount of ink is ejected. On the other hand, where the waves of the flutes F are lowest, the flutes F become concave parts and are printed only on the liner L, so ink is more likely to bleed if a large amount of ink is ejected. If ink bleeds, there is a risk of a decrease in the reading accuracy of code information such as barcodes and QR codes.

[0024] Therefore, in order to suppress bleeding of ink in the concave portions of the flutes F, the control unit 30 of this embodiment controls the amount of ink based on the correction waveform having a waveform in phase with the flutes F as described above. Specifically, the control unit 30 reduces the amount of ink ejected into the concave portions of the flutes F.

[0025] FIG. 4 is a diagram for explaining control of ink ejection from each ink-jet head 25 based on the correction waveform.

[0026] First, the control unit 30 outputs a pulse signal with a predetermined period to each inkjet head 25, and ink is ejected from each nozzle of each inkjet head 25 in response to the rising edge of the pulse signal.

[0027] Fig. 4A is a diagram showing an example of pulse signals supplied to inkjet heads 25 arranged at the same position in each of the line heads 21 to 24 of C, M, Y, and K. The inkjet heads 25 arranged at the same position refer to the inkjet heads 25 arranged at the same position in each of the line heads 21 to 24 among the six inkjet heads 25 in each of the line heads 21 to 24. For example, the inkjet heads 25_1, 25_2, 25_3, and 25_4 in Fig. 2 are inkjet heads arranged at the same position.

[0028] As shown in FIG. 4A, the period of the pulse signals of the inkjet heads 25 that eject ink of each color is the same, but the phases are shifted depending on the position of each inkjet head 25.

[0029] Fig. 4C shows an example of a flute F of a cardboard P, and Fig. 4B shows an example of a correction waveform generated based on the flute F shown in Fig. 4C. In this embodiment, the correction waveform shown in Fig. 4B is expressed as 0.75 + 1 / 4 sinA(ω), with a minimum value of 0.5 and a maximum value of 1.0. Note that A changes depending on the flute F, and ω has a value in phase with the flute.

[0030] In addition, the phase of the pulse signal of the inkjet head 25 of each color shown in FIG. 4A and the phase of the correction waveform (phase of the flute) are adjusted in advance based on the positional relationship between the print start position on the cardboard P and each inkjet head.

[0031] The control unit 30 then determines the amount of ink to be ejected from the inkjet head 25 of each color based on the pulse signal of the inkjet head 25 of each color shown in FIG. 4A and the correction waveform shown in FIG. 4B. Specifically, when ink is ejected from the inkjet head 25 of K in response to the rising edge of the pulse signal at time t1, the control unit 30 determines the value of the correction waveform corresponding to time t1 as a correction value, and multiplies the correction value by the amount of ink ejected from the inkjet head 25 of K to determine the amount of ink after correction. The ink amount before multiplication by the correction value is the ink amount previously determined according to the density of the print image. By multiplying the correction value in this way, the previously set ink amount can be reduced.

[0032] Similarly, when ink is ejected from the C inkjet head 25 in response to the rising edge of the pulse signal at time t2, when ink is ejected from the M inkjet head 25 in response to the rising edge of the pulse signal at time t3, and when ink is ejected from the Y inkjet head 25 in response to the rising edge of the pulse signal at time t4, the control unit 30 determines the correction waveform values ​​corresponding to times t2, t3, and t4 as correction values, and multiplies the correction values ​​for each color by the amount of ink ejected from the inkjet head 25 for each color to determine the corrected ink amount.

[0033] Note that, although the method for obtaining the correction values ​​corresponding to some of the pulse signals of each color has been described here, in reality, correction values ​​corresponding to all of the pulse signals supplied to all of the inkjet heads 25 are obtained, and the correction values ​​are multiplied by a preset ink amount to determine the corrected ink amount.

[0034] By determining the corrected ink amount as described above, the ink amount can be reduced in the concave portions of the flutes F, thereby suppressing ink bleeding. Also, since the ink amount can be set to a preset amount in the convex portions of the flutes F, a print result of the desired density can be obtained.

[0035] Next, in the above embodiment, as shown in Figure 1, the direction in which the unevenness of the flutes F of the cardboard P continues (the direction of the arrow Y2 shown in Figure 1) is the same as the conveying direction of the cardboard P. However, as shown in Figure 5, a case will be described in which the direction in which the unevenness of the flutes F of the cardboard P continues (the direction of the arrow Y2 shown in Figure 5) is perpendicular to the conveying direction of the cardboard P.

[0036] When the direction in which the concaves and convexes of the flutes F of the cardboard P continue is perpendicular to the conveyance direction of the cardboard P, the direction in which the concaves and convexes of the flutes F of the cardboard P continue and the arrangement direction of the nozzles of each of the line heads 21-24 (the direction of the arrow X shown in FIG. 5) have the same relationship. FIG. 6 is a diagram for explaining ink ejection control based on a correction waveform when the direction in which the concaves and convexes of the flutes F of the cardboard P continue and the arrangement direction of the nozzles of the six inkjet heads 25 of each of the line heads 21-24 are the same.

[0037] When the direction in which the concaves and convexes of the flutes F of the cardboard P continue is the same as the arrangement direction of the nozzles of the inkjet head 25, a correction value is obtained based on the correction waveform for each nozzle of the inkjet head 25. It is assumed that the positional relationship between the position of the inkjet head 25 shown in Fig. 6A and the positional relationship between the flutes F of the cardboard P shown in Fig. 6C has been adjusted in advance.

[0038] Specifically, the correction waveform shown in FIG. 6B is expressed as 0.75+1 / 4 sinA(ω) in the same manner as in the above embodiment, with the minimum value being 0.5 and the maximum value being 1.0.

[0039] Then, the control unit 30 obtains a correction value corresponding to the position of each nozzle based on the nozzle position information shown in FIG. 6A and the correction waveform shown in FIG. 6B, and determines the amount of ink ejected from each nozzle based on the correction value. Specifically, for example, when ink is ejected from a nozzle at nozzle position p1, the control unit 30 obtains the value of the correction waveform corresponding to nozzle position p1 as a correction value, and multiplies the correction value by the amount of ink ejected from the nozzle at nozzle position p1 to determine the amount of ink after correction. The ink amount before multiplication by the correction value is the ink amount obtained in advance according to the density of the print image. By multiplying the correction value in this way, the ink amount that was set in advance can be reduced.

[0040] Similarly, when ink is ejected from a nozzle at nozzle position p2, when ink is ejected from a nozzle at nozzle position p3, and when ink is ejected from a nozzle at nozzle position p4, the control unit 30 determines the value of the correction waveform corresponding to the nozzle positions p2, p3, and p4 as a correction value, and multiplies the correction value by the amount of ink ejected from the nozzle at nozzle positions p2, p3, and p4 to determine the amount of ink after correction.

[0041] By determining the corrected ink amount as described above, the ink amount can be reduced in the concave portions of the flutes F, thereby suppressing ink bleeding. Also, since the ink amount can be set to a preset amount in the convex portions of the flutes F, a print result of the desired density can be obtained.

[0042] In addition, when the direction in which the unevenness of the flutes F of the cardboard P continues is the same as the arrangement direction of the nozzles of each line head 21 to 24, there is no change in the unevenness of the surface of the cardboard P in the transport direction, so the correction value of each nozzle does not change in the transport direction, and the same correction value is used from the start of printing on the cardboard P to the end of printing.

[0043] The control unit 30 may also change the ink ejection control depending on whether the direction in which the concaves and convexes of the flutes F of the cardboard P continue is parallel to the transport direction or perpendicular to it. Specifically, the control unit may obtain information indicating whether the direction in which the concaves and convexes of the flutes F continue is parallel or perpendicular to the transport direction, and switch between the ink amount control described in Fig. 4 and the ink amount control described in Fig. 6 based on the obtained information. The information indicating whether the direction in which the concaves and convexes of the flutes F continue is parallel or perpendicular to the transport direction may be set and input by the user, for example.

[0044] In the above explanation, a correction waveform that is in phase with the wave of the flute F is used to suppress bleeding and improve the reading accuracy of code information such as barcodes and QR codes. However, when printing image information such as photographs or illustrations, if the ink amount is determined as described above, the density of the printed image will be high in the convex parts of the flute F and low in the concave parts, which may cause unevenness and degradation of image quality.

[0045] Therefore, when printing image information such as photographs or illustrations, the opposite phase of the wave of the flute F may be used as the correction waveform. The method of determining the amount of ink from the correction waveform is the same as when using the correction waveform of the same phase. By using the correction waveform of the opposite phase in this way, the amount of ink is reduced in the convex parts of the flute F and the amount of ink is increased in the concave parts, making it possible to reduce the shading of the printed image caused by the surface unevenness.

[0046] Furthermore, the control unit 30 may be configured to switch between an in-phase correction waveform and an opposite-phase correction waveform, for example, when printing code information and when printing image information on the cardboard P. The correction waveform may be switched by, for example, a user setting and inputting whether to use an in-phase correction waveform or an opposite-phase correction waveform, or the control unit 30 may obtain information on whether to print code information or image information, and automatically switch the correction waveform based on that information. The information on whether to print code information or image information may be set and input by the user, or may be obtained from print job information.

[0047] In addition, the control unit 30 may control the amount of ink based on the same phase correction waveform only when printing code information, and when printing image information, control the amount of ink based on a preset density of the print image without controlling the amount of ink based on the correction waveform.

[0048] Also, the control unit 30 may control the amount of ink based on the correction waveform only when a specific color is printed. For example, code information is often printed in black (K) and is also greatly affected by bleeding, so when printing black (K), the amount of ink may be controlled based on a correction waveform of the same phase, and when printing other colors, the amount of ink may not be controlled based on the correction waveform, or the amount of ink may be controlled based on a correction waveform of the opposite phase.

[0049] The structural information of the flutes F of the cardboard P or the correction waveform corresponding to the structural information of the flutes F is stored in advance in a storage medium such as a semiconductor memory or a hard disk of the control unit 30. The structural information of the flutes F or the correction waveform may be stored in advance as a default in the inkjet printing device 1, or may be freely registered by the user.

[0050] Also, for example, as shown in FIG. 7, the relationship between the type of flute (commonly known flute A, flute B, etc.) and the correction waveform may be stored in advance in a table or the like, and when the user sets and inputs the type of flute to be printed, the control unit 30 may determine the correction waveform by referring to the table shown in FIG. 7.

[0051] Also, the structure of the flutes F of the cardboard P to be printed may be detected by a predetermined waveform detector and acquired by the control unit 30.

[0052] The waveform detection section may be, for example, a contact sensor that comes into contact with the surface of the unprinted cardboard P transported by the transport unit 10 and detects the unevenness of the surface of the cardboard P. More specifically, a wheel with a suspension may be provided so as to come into contact with the surface of the cardboard P, and the height of the cardboard P and the period of the unevenness may be read by detecting the up and down movement of the wheel with a pressure sensor or the like as the cardboard P is transported.

[0053] The period of the flutes F may also be detected by capturing an image of the surface of the cardboard P using, for example, an image sensor. Specifically, a light and a camera may be installed on the transport path of the transport unit 10, and the light may be shone on the unprinted cardboard P being transported, the camera may capture an image of the surface of the cardboard P, and the period of the flutes F may be determined by detecting stripes that appear in the captured image. When the period of the flutes F is determined by capturing an image in this manner, the height of the flutes F may be detected by a separate sensor or the like, or may be set and input by the user.

[0054] As described above, the period, height and start intercept of the irregularities of the flutes F of the cardboard P can be detected, and the control unit 30 can generate a correction waveform based on this information.

[0055] The control unit 30 may also generate a correction waveform according to the material of the cardboard P. Specifically, as described above, a correction waveform may be generated based on structural information about the flutes F of the cardboard P, and the minimum value of the correction waveform may be adjusted according to the material of the liner of the cardboard P. For example, the minimum value may be made smaller as the liner material is more susceptible to bleeding. Information about the material of the cardboard P may be set and input by the user, or may be selected from materials stored in advance.

[0056] In addition, in the description of the above embodiment, the wave shape of the flutes F is an ideal sine curve, but the wave shape of the flutes F may be crushed or chipped due to defects in the formation of the corrugated cardboard P during its manufacture or due to various processes and transportation.

[0057] Therefore, the correction waveform may be approximated to the waveform of the flutes F of the current corrugated cardboard P using not only a sine function but also a continuous function or a discrete function such as a composite function of trigonometric functions.

[0058] FIG. 8A shows an ideal shape of a flute F in dotted lines and a deformed shape of a flute F in solid lines. The part indicated by the arrow in FIG. 8A is the deformed part. FIG. 8B shows an example of a correction waveform generated based on the deformed shape of the flute F shown in FIG. 8A. FIG. 8B shows an example of a correction waveform generated by combining a sine function and an approximation function according to the deformation of the flute F. The correction waveform in FIG. 8B is an example in which an approximation function is inserted between sine functions. The approximation function is divided into three parts a to c, a and c are linear functions, and b is an n-th order function.

[0059] The control unit 30 may obtain the crushing and chipping of the waves of the flute F using the waveform detection unit described above and generate a correction waveform, or multiple correction waveforms that take into account the crushing and chipping of the waves of the flute F may be generated in advance and stored, and the user may select from the multiple correction waveforms to use, taking into account the degree of crushing based on the appearance and usage history.

[0060] Furthermore, the cardboard P absorbs the ink when printed, and the shape is restored and changed according to the moisture content of the cardboard P. Therefore, a correction waveform may be generated taking into account the restoration rate of the waveform of the flutes F according to the moisture content of the cardboard P. Also, for example, a plurality of correction waveforms for each cardboard P with different restoration rates may be generated and stored in advance, and the user may select a correction waveform according to the restoration rate of the cardboard P to be printed from the plurality of correction waveforms. Furthermore, since the amount of ink absorbed by the cardboard P differs depending on the type of ink, a correction waveform according to the type of ink or a correction waveform according to both the type of ink and the type of cardboard P may be selected.

[0061] In addition, as described above, a message may be displayed asking the user whether or not to use a correction waveform that takes into account the restoration rate of the waveform of the flute F, and if the user sets and inputs an approval instruction, a correction waveform that takes into account the restoration rate of the waveform of the flute F may be used.

[0062] According to the inkjet printing device 1 of the above embodiment, the amount of ink ejected from the inkjet head 25 is controlled based on a correction waveform having a waveform that is in phase or opposite phase with the flute F, thereby suppressing the adverse effects on the printed image caused by unevenness on the surface of the cardboard P.

[0063] Furthermore, in the inkjet printing device 1 of the above embodiment, if the ink ejection control is changed depending on whether the direction in which the unevenness of the flutes F continues is parallel or perpendicular to the conveying direction, it is possible to control the amount of ink appropriately regardless of how the cardboard P is installed.

[0064] Furthermore, in the inkjet printing device 1 of the above embodiment, if the correction waveform is changed according to the type of flute F, it is possible to suppress the adverse effects on the printed image caused by unevenness on the surface of the cardboard P for cardboard P with various flutes F.

[0065] Furthermore, in the inkjet printing device 1 of the above embodiment, if a correction waveform is generated based on the waveform detected by the waveform detection unit described above, the amount of ink can be appropriately controlled even when printing on cardboard P whose flute F structure is not known in advance.

[0066] Furthermore, in the inkjet printing device 1 of the above embodiment, if a correction waveform based on information regarding the condition of the cardboard P (for example, information regarding the flattening or chipping of the waves of the flutes F) is used, the amount of ink can be appropriately controlled even if the condition of the cardboard P is not normal.

[0067] Furthermore, in the inkjet printing device 1 of the above embodiment, if a correction waveform based on the type of ink, the material of the cardboard P, or the restoration rate of the cardboard P due to ink absorption is used, the amount of ink can be appropriately controlled using a correction waveform that takes into account the amount of ink absorbed by the cardboard P and the restoration of the cardboard P due to ink absorption.

[0068] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, all the components shown in the embodiment can be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention.

[0069] The present invention further discloses the following supplementary notes.

[0070] (Appendix 1) The printing device of the present invention is a printing device comprising an ejection section that ejects ink onto cardboard having a corrugated flute as a center core, and a control section that controls the amount of ink ejected from the ejection section based on a correction waveform having a waveform that is in phase or opposite phase with the flutes.

[0071] (Appendix 2) The printing device described in Appendix 1 is provided with a transport unit that transports at least one of the cardboard and the ejection unit relatively in a predetermined transport direction, and the control unit can change the ink ejection control depending on whether the direction in which the flute's irregularities continue is parallel to the transport direction or perpendicular to it.

[0072] (Appendix 3) In the printing device according to Supplementary Note 1 or 2, the control unit can change the correction waveform according to the type of flute.

[0073] (Appendix 4) The printing device described in Supplementary Note 1 to Supplementary Note 3 includes a waveform detection unit that detects the waveform of the flute, and the control unit can generate a correction waveform based on the waveform detected by the waveform detection unit.

[0074] (Appendix 5) In the printing device described in Supplementary Note 1 to Supplementary Note 4, the control unit can use a correction waveform based on information regarding the state of the cardboard.

[0075] (Appendix 6) In the printing device according to any one of claims 1 to 5, the control unit can use a correction waveform based on at least one of information on the type of ink and information on the material of the cardboard.

[0076] (Appendix 7) In the printing device described in Supplementary Note 1 to Supplementary Note 6, the control unit can use a correction waveform based on information regarding the restoration rate of the cardboard due to the absorption of ink.

[0077] (Appendix 8) In the printing method of the present invention, when ink is ejected onto cardboard having wave-shaped flutes as a core, the amount of ink is controlled based on a correction waveform having a waveform in phase or opposite phase to the flutes. [Explanation of symbols]

[0078] 1 Inkjet printing device 10 Transport unit 11,12 Platen roller 13 Conveyor belt 20 Head Unit 21~24 Line Head 25 Inkjet head 30 Control section F flute L Liner P Cardboard

Claims

1. an ejection unit that ejects ink onto a corrugated cardboard having a corrugated flute as a core; a control unit that controls the amount of ink ejected from the ejection unit based on a correction waveform having a waveform in phase or opposite phase to that of the flute.

2. a conveying unit that conveys at least one of the cardboard and the discharge unit relatively in a predetermined conveying direction, 2. The printing apparatus according to claim 1, wherein the control unit changes the ejection control of the ink depending on whether a direction in which the concaves and convexes of the flutes continue is parallel to the transport direction or perpendicular to the transport direction.

3. The printing apparatus according to claim 1 , wherein the control unit changes the correction waveform in accordance with the type of the flute.

4. A waveform detection unit is provided for detecting the waveform of the flute, 2. The printing apparatus according to claim 1, wherein the control unit generates the correction waveform based on the waveform detected by the waveform detection unit.

5. 2. The printing apparatus according to claim 1, wherein the control unit uses the correction waveform based on information regarding the state of the cardboard.

6. 2. The printing apparatus according to claim 1, wherein the control unit uses the correction waveform based on at least one of information on the type of ink and information on the material of the cardboard.

7. 2. The printing device according to claim 1, wherein the control unit uses the correction waveform based on information regarding a restoration rate of the cardboard due to absorption of the ink.

8. When ink is discharged onto a corrugated cardboard having a corrugated flute as a core, A printing method in which the amount of ink is controlled based on a correction waveform having a waveform in phase or opposite phase to that of the flute.

Images