Printing device and its maintenance method

Abstract

To provide a printing device that has an auto-splice function and can execute appropriate maintenance in which printing processing scheduled to be executed after exchanging a roll paper is taken into consideration, in exchanging the roll paper.SOLUTION: When a roll paper to be used is exchanged from a precedent roll paper to a subsequent roll paper with a splicer 213, a printing control part 153 controls motion of a printing part 24 so that an inspection pattern is printed on an ending of a continuous paper wound off from the precedent roll paper. A maintenance content control part 151 determines maintenance-contents for an inkjet head, on the basis of an inspected result obtained in inspecting a printed image for the inspection pattern, in accordance with criteria for determination suitable for printing on the continuous paper wound off from the subsequent roll paper.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a printing apparatus and a maintenance method thereof.

Background Art

[0002] Conventionally, an inkjet printing apparatus that performs printing by discharging ink onto a substrate (printing medium) such as printing paper is known. In an inkjet printing apparatus, when the discharge interval becomes long, during the period of printing, drying of the ink due to evaporation of the solvent near the nozzles, mixing of air bubbles into the nozzles, adhesion of dust to the nozzles, etc. may occur. When such a phenomenon occurs, normal discharge etc. cannot be performed, and there is a possibility of printing defects. Therefore, maintenance for avoiding such problems is carried out at any time.

[0003] Maintenance is roughly classified into cleaning such as wiping (removing dirt) the nozzle surface of an inkjet head (printing head) using a dedicated mechanism, and flushing that forcibly executes an ink discharge operation irrelevant to the printed content. Flushing can be executed during the conveyance of the printing paper, but cleaning needs to be executed while the conveyance of the printing paper is stopped. There are various modes of the flushing method, such as star flushing (discrete flushing) that discharges ink thinly over the entire page to be printed, and line flushing that discharges ink simultaneously from a plurality of nozzles for a predetermined line of a certain page.

[0004] Regarding maintenance as described above, Japanese Patent Application Laid-Open No. 2011-152689 discloses a printing apparatus that determines whether the ejection state is a normal state, a clogged state, or an unstable ejection state based on measured values indicating the ejection state of ink, and performs different maintenance according to the determination result. In that printing apparatus, for example, when it is determined that the ejection state of the ink is a clogged state, maintenance including an ink suction operation is performed; when it is determined that the ejection state of the ink is an unstable ejection state, maintenance not including an ink suction operation is performed; and when it is determined that the ejection state of the ink is a normal state, no maintenance is performed.

[0005] Also, Pamphlet of International Publication No. 2015 / 163087 discloses a maintenance system for an inkjet recording apparatus, which includes a maintenance level determination criterion correction unit that corrects a maintenance level determination criterion for determining the content of maintenance to be performed. In that maintenance system, for example, the maintenance level determination criterion is automatically corrected based on the processing time of the job to be processed next to the current job. To give a more specific example, when the processing time of the job to be processed next is longer than the standardly defined processing time, the maintenance level determination criterion is corrected so that maintenance with a high recovery ability is performed even at a low ejection abnormality level.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In recent years, printing devices having an auto splice function have been developed. The auto splice function is a function that automatically joins the end portion of the roll paper in use and the start portion of the next roll paper to be used using an adhesive tape or the like when the remaining amount of the roll paper in use becomes small. According to such a printing device having an auto splice function, manual roll paper replacement work is not required, so the printing time is shortened.

[0008] According to a conventional printing device, maintenance is not performed when continuous printing is performed on a plurality of roll papers using the auto splice function. However, before and after the replacement of the roll paper, the head (inkjet head) to be used may change or the level of print quality required by the user may change. In such a case, it is considered preferable to perform maintenance. Note that neither Japanese Patent Application Laid-Open No. 2011-152689 nor International Publication No. 2015 / 163087 pamphlet describes maintenance when roll paper is replaced using the auto splice function.

[0009] Therefore, an object of the present invention is to realize a printing device capable of performing suitable maintenance in consideration of a printing process scheduled to be executed after replacement when roll paper is replaced in a printing device having an auto splice function.

Means for Solving the Problems

[0010] A first invention is a printing device, a printing unit including a printing head that performs printing by discharging ink onto a continuous sheet unwound from a roll paper; a print control unit that controls the operation of the printing unit; a maintenance mechanism that performs maintenance on the printing head; an inspection device that inspects a printed image obtained by printing by the printing unit; a maintenance content control unit that determines maintenance content for the printing head; A maintenance mechanism control unit that controls the operation of the maintenance mechanism so that maintenance of the maintenance content determined by the maintenance content control unit is performed on the print head, A splice unit that joins the end of the preceding roll paper that has already been the object of use and the start end of the succeeding roll paper that will be the next object of use, and exchanges the roll paper to be used from the preceding roll paper to the succeeding roll paper and includes, When the roll paper to be used is exchanged from the preceding roll paper to the succeeding roll paper by the splice unit, the print control unit controls the operation of the print unit so that an inspection pattern is printed at the end of the continuous paper unwound from the preceding roll paper, The maintenance content control unit determines the maintenance content for the print head based on the inspection result obtained from the inspection of the printed image of the inspection pattern by the inspection device according to the determination criteria suitable for printing on the continuous paper unwound from the succeeding roll paper.

[0011] A second invention is, in the first invention, When a part of the first print head group, which is a set of print heads used before the roll paper is exchanged by the splice unit, becomes unused after the roll paper is exchanged by the splice unit, the maintenance content control unit only for the second print head group, which is a set of print heads used after the roll paper is exchanged by the splice unit among the print heads, determines the maintenance content according to the determination criteria suitable for printing on the continuous paper unwound from the succeeding roll paper.

[0012] A third invention is, in the second invention, In the inspection by the inspection device, detection of defects in the print head is performed, If the second print head group does not include a print head in which a defect has been detected by the inspection by the inspection device, the maintenance content control unit determines that none of the print heads are to be the object of maintenance.

[0013] The fourth invention is in the second invention, if the second print head group includes a print head in which a defect is detected by the inspection by the inspection device, the maintenance content control unit determines whether maintenance of the second print head group is necessary, and if it is determined that maintenance of the second print head group is necessary, among the second print head group, the print head in which a defect is detected by the inspection by the inspection device and the print head that becomes unused after replacement of the roll paper by the splicing unit are determined to be maintenance targets, and if it is determined that maintenance of the second print head group is not necessary, it is determined that none of the print heads are maintenance targets.

[0014] The fifth invention is in any one of the second to fourth inventions, wherein the paper width of the subsequent roll paper is narrower than the paper width of the preceding roll paper.

[0015] The sixth invention is in any one of the second to fourth inventions, the first print head group is a set of print heads used for color printing, and the second print head group is a set of print heads used for monochrome printing.

[0016] The seventh invention is in any one of the second to fourth inventions, the first print head group is a set of print heads used for double-sided printing, and the second print head group is a set of print heads used for single-sided printing.

[0017] The eighth invention is in the first invention, The fourth print head group, which is a set of print heads used after the roll paper is replaced by the splicing unit, is composed of a fifth print head group, which is a set of print heads used before the roll paper is replaced by the splicing unit, and a sixth print head group, which is a set of print heads not used before the roll paper is replaced by the splicing unit. The maintenance content control unit is characterized by determining that all the print heads included in the sixth print head group are to be the maintenance targets.

[0018] A ninth invention is as follows in the eighth invention. The maintenance content control unit is characterized by determining, only for the fifth print head group, the print heads to be the maintenance targets according to the determination criteria suitable for printing on the continuous paper unwound from the subsequent roll paper.

[0019] A tenth invention is as follows in the eighth or ninth invention. The paper width of the subsequent roll paper is characterized by being wider than the paper width of the preceding roll paper.

[0020] An eleventh invention is as follows in the eighth or ninth invention. The fifth print head group is a set of print heads used for monochrome printing, and the fourth print head group is characterized by being a set of print heads used for color printing.

[0021] A twelfth invention is as follows in the eighth or ninth invention. The fifth print head group is a set of print heads used for single-sided printing, and the fourth print head group is characterized by being a set of print heads used for double-sided printing.

[0022] A thirteenth invention is as follows in the first invention. The determination criteria are determined for each job. The maintenance content control unit determines according to the determination criterion in which the number of print heads determined as maintenance targets is the largest among the determination criteria defined for a plurality of jobs for which printing by the printing unit is scheduled to be executed from when the roll paper to be used is replaced by the splicing unit from the preceding roll paper to the succeeding roll paper until the roll paper to be used is further replaced by the splicing unit from the succeeding roll paper to the next roll paper.

[0023] The 14th invention is any one of the inventions from the 1st to the 13th, The printing control unit controls the operation of the printing unit so that an inspection pattern is printed at the head of the continuous paper unwound from the succeeding roll paper, The maintenance content control unit further determines whether to stop printing by the printing unit on the continuous paper unwound from the succeeding roll paper based on the inspection result obtained from the inspection of the printed image of the inspection pattern printed at the head of the continuous paper unwound from the succeeding roll paper by the inspection device.

[0024] The 15th invention is any one of the inventions from the 1st to the 14th, Pre Mark As types of maintenance for the print head, cleaning and flushing are prepared, The maintenance content control unit further determines the type of maintenance to be executed according to the determination criterion suitable for printing on the continuous paper unwound from the succeeding roll paper.

[0025] The 16th invention is any one of the inventions from the 1st to the 15th, When the remaining amount of the preceding roll paper becomes equal to or less than a predetermined threshold, the splicing unit outputs a splice trigger signal that triggers the replacement of the roll paper. The printing control unit controls the operation of the printing unit so that an inspection pattern is printed at the end of the continuous paper unwound from the preceding roll paper based on the splice trigger signal.

[0026] A 17th invention is a maintenance method for a printing apparatus including a printing unit including a print head that performs printing by discharging ink onto a continuous paper unwound from a roll paper, and a splice unit that joins a terminal end of a preceding roll paper that has already been used and a start end of a succeeding roll paper that is to be used next and exchanges the roll paper to be used from the preceding roll paper to the succeeding roll paper, the method comprising: an inspection pattern printing step in which the printing unit prints an inspection pattern at the end of the continuous paper unwound from the preceding roll paper; an inspection step of inspecting a printed image of the inspection pattern; a roll paper replacement step in which the splice unit exchanges the roll paper to be used from the preceding roll paper to the succeeding roll paper; a maintenance content control step of determining maintenance content for the print head according to a determination criterion suitable for printing on the continuous paper unwound from the succeeding roll paper based on the inspection result obtained in the inspection step; a maintenance step of performing maintenance of the maintenance content determined in the maintenance content control step on the print head and characterized by including the above.

Effect of the Invention

[0027] According to the first invention described above, a printing apparatus having an auto-splice function is provided with a maintenance mechanism for performing maintenance on a print head, a maintenance content control unit for determining the maintenance content for the print head, and a maintenance mechanism control unit for controlling the operation of the maintenance mechanism so that maintenance of the maintenance content determined by the maintenance content control unit is performed. When the roll paper to be used is replaced, the maintenance content control unit determines the maintenance content for the print head according to the determination criteria suitable for printing on the continuous paper unwound from the roll paper after replacement, based on the inspection results for the inspection pattern. Thereby, when the roll paper is replaced, maintenance of the print head is performed according to the printing process to be executed after replacement. As described above, a printing apparatus capable of performing suitable maintenance in consideration of the printing process scheduled to be executed after replacement when the roll paper is replaced and having an auto-splice function is realized.

[0028] According to the second invention described above, when some of the print heads used before the replacement of the roll paper are no longer used after the replacement of the roll paper, the necessity of maintenance for each print head used after the replacement of the roll paper is suitably determined.

[0029] According to the third invention described above, it is possible to suppress the execution of unnecessary maintenance and shorten the printing time.

[0030] According to the fourth invention described above, when maintenance of the print head used after the replacement of the roll paper is performed, maintenance of the print head that will no longer be used after the replacement of the roll paper is also performed. Thereby, maintenance is efficiently performed. Also, when maintenance of the print head used after the replacement of the roll paper is not performed, maintenance of the print head that will no longer be used after the replacement of the roll paper is not performed either. Thereby, it is possible to suppress the execution of unnecessary maintenance and shorten the printing time.

[0031] According to the fifth invention described above, when changing from a roll of wide paper to a roll of narrow paper, suitable maintenance is performed according to the printing process on the continuous narrow paper.

[0032] According to the sixth invention described above, when switching from color printing to monochrome printing before and after replacing the roll paper, suitable maintenance is performed in consideration of the execution of monochrome printing.

[0033] According to the seventh invention described above, when switching from double-sided printing to single-sided printing before and after replacing the roll paper, suitable maintenance is performed in consideration of the execution of single-sided printing.

[0034] According to the eighth invention described above, since the print head that changes from the unused state to the used state before and after replacing the roll paper is surely maintained, the occurrence of ejection failure of the print head in the unused state is effectively suppressed.

[0035] According to the ninth invention described above, the necessity of maintenance for each print head maintained in the used state from before to after replacing the roll paper is preferably determined.

[0036] According to the tenth invention described above, when changing from a roll of narrow paper to a roll of wide paper, suitable maintenance is performed according to the printing process on the continuous wide paper.

[0037] According to the eleventh invention described above, when switching from monochrome printing to color printing before and after replacing the roll paper, suitable maintenance is performed in consideration of the execution of color printing.

[0038] According to the twelfth invention described above, when switching from single-sided printing to double-sided printing before and after replacing the roll paper, suitable maintenance is performed in consideration of the execution of double-sided printing.

[0039] According to the 13th invention described above, when a plurality of jobs are to be printed between the replacement of the roll paper until the next replacement of the roll paper, the occurrence of ejection defects of the print head used in the printing of these plurality of jobs is effectively suppressed.

[0040] According to the 14th invention described above, it becomes possible to effectively suppress the occurrence of printing defects after the replacement of the roll paper.

[0041] According to the 15th invention described above, by suitably differentiating between cleaning and flushing, it becomes possible to suppress a decrease in printing efficiency while maintaining print quality.

[0042] According to the 16th invention described above, not only the joining of the end portion of the preceding roll paper and the start portion of the succeeding roll paper but also the printing of the inspection pattern can be automatically executed.

[0043] According to the 17th invention described above, the same effect as that of the 1st invention is obtained.

Brief Description of the Drawings

[0044]

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MODE FOR CARRYING OUT THE INVENTION

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0046] <1. First Embodiment> <1.1 Overall Configuration of Printing System> FIG. 1 is an overall configuration diagram of a printing system according to a first embodiment of the present invention. This printing system is composed of an inkjet printing apparatus 10 and a print data generation apparatus 40. The inkjet printing apparatus 10 and the print data generation apparatus 40 are connected to each other by a communication line 5. The print data generation apparatus 40 performs RIP processing or the like on input data such as a PDF file to generate print data. The print data generated by the print data generation apparatus 40 is transmitted to the inkjet printing apparatus 10 via the communication line 5. The inkjet printing apparatus 10 outputs a printed image on printing paper as a printing medium based on the print data transmitted from the print data generation apparatus 40 without using a printing plate. The inkjet printing apparatus 10 is composed of a printing machine main body 200, a print control apparatus 100 that controls the operation of the printing machine main body 200, and an image inspection apparatus 300 that inspects the printing state. That is, this inkjet printing apparatus 10 is a printing apparatus with an inspection function. Some components of the image inspection apparatus 300 are built into the printing machine main body 200.

[0047] Note that in the configuration shown in FIG. 1, the image inspection apparatus 300 is a component of the inkjet printing apparatus 10 (that is, the image inspection apparatus 300 is included in the inkjet printing apparatus 10), but it is not limited thereto. The image inspection apparatus 300 may be an independent apparatus separate from the inkjet printing apparatus 10.

[0048] <1.2 Configuration of Inkjet Printing Apparatus> FIG. 2 is a schematic diagram showing a configuration example of the inkjet printing apparatus 10. As described above, this inkjet printing apparatus 10 is composed of a print control apparatus 100, a printing machine main body 200, and an image inspection apparatus 300.

[0049] The printing machine main body 200 includes a paper feeding unit 21 that supplies printing paper (roll paper) PA, a printing mechanism 20 that performs printing on the printing paper PA, and a paper winding unit 28 that winds up the printed printing paper PA. The printing mechanism 20 includes a first driving roller 22 for conveying the printing paper PA inside, a plurality of support rollers 23 for conveying the printing paper PA inside the printing mechanism 20, a printing unit 24 that discharges ink onto the printing paper PA to perform printing, a cleaning mechanism 25 that performs cleaning of the printing unit 24 (for example, suction of ink from nozzles and wiping of the nozzle surface described later), a drying unit 26 that dries the printed printing paper PA, an imaging unit 310 that images the printed image (printed printing paper PA), and a second driving roller 27 for outputting the printing paper PA from inside the printing mechanism 20. The imaging unit 310 is a component of the image inspection device 300 and is configured using an image sensor such as a CCD or CMOS.

[0050] The printing control device 100 controls the operation of the printing machine main body 200 having the above configuration. When an instruction command for printing output is given to the printing control device 100, the printing control device 100 controls the operation of the printing machine main body 200 so that the printing paper PA is conveyed from the paper feeding unit 21 to the paper winding unit 28. First, printing on the printing paper PA is performed by the printing unit 24, then the printing paper PA is dried by the drying unit 26, and finally the printed image is imaged by the imaging unit 310. Also, if necessary, cleaning of the printing unit 24 by the cleaning mechanism 25 is performed.

[0051] The image inspection apparatus 300 is composed of an imaging unit 310 and an image inspection computer 320. The captured image data Di obtained by imaging the printed image by the imaging unit 310 is sent to the image inspection computer 320. In the image inspection computer 320, an inspection is performed to analyze the captured image data Di and detect defects (deficiencies). Note that the inspection is not limited to such a method, and an inspection for detecting defects (deficiencies) may be performed by comparing and collating the captured image data Di with the print data Dp transmitted from the print data generation device 40, or by comparing and collating the captured image data Di with the inspection image data Dc. The inspection result Dr obtained by the image inspection computer 320 is sent to the print control device 100.

[0052] FIG. 3 is a plan view showing a configuration example of the printing unit 24. As shown in FIG. 3, the printing unit 24 is composed of inkjet head arrays 240C, 240M, 240Y, and 240K of C color (cyan), M color (magenta), Y color (yellow), and K color (black) arranged in a row in the conveyance direction of the printing paper PA. Each inkjet head array is composed of a plurality of inkjet heads (printing heads) 241 arranged in a staggered manner. Each inkjet head 241 includes a number of nozzles for discharging ink. Each nozzle of the inkjet head 241 included in the C color inkjet head array 240C discharges C color ink, each nozzle of the inkjet head 241 included in the M color inkjet head array 240M discharges M color ink, each nozzle of the inkjet head 241 included in the Y color inkjet head array 240Y discharges Y color ink, and each nozzle of the inkjet head 241 included in the K color inkjet head array 240K discharges K color ink.

[0053] Incidentally, this inkjet printing apparatus 10 has the auto splice function described above. Therefore, as shown in FIG. 4, the paper feeding unit 21 includes two unwinding units 211 and 212 and a splicer (splice unit) 213. When the remaining amount of the roll paper RL1 unwound from the unwinding unit 211 becomes small, for example, the splicer 213 joins the end portion of the roll paper RL1 and the start portion of the roll paper RL2 unwound from the unwinding unit 212 using an adhesive tape or the like. Thereby, the printing paper used for printing is changed from the roll paper RL1 to the roll paper RL2. Thus, in the inkjet printing apparatus 10 in the present embodiment, the roll paper to be used can be exchanged without stopping the conveyance of the printing paper PA.

[0054] Here, the configuration of the inkjet printing apparatus 10 that performs color printing has been illustrated. However, the present invention can also be applied when an inkjet printing apparatus that performs monochrome printing is adopted. Also, here, the configuration of the inkjet printing apparatus 10 that uses aqueous ink has been illustrated. However, the present invention can also be applied when an inkjet printing apparatus that uses UV ink (ultraviolet curable ink), such as an inkjet printing apparatus for label printing, is adopted. As described above, as long as it has an auto splice function and includes a printing unit that discharges ink and requires cleaning, the type of the printing apparatus is not particularly limited.

[0055] <1.3 Hardware Configuration of Printing Control Device> FIG. 5 is a block diagram showing the hardware configuration of the printing control apparatus 100. As shown in FIG. 5, the printing control apparatus 100 includes a main body 110, an auxiliary storage device 121, an optical disk drive 122, a display unit 123, a keyboard 124, and a mouse 125. The main body 110 includes a CPU 111, a memory 112, a first disk interface unit 113, a second disk interface unit 114, a display control unit 115, an input interface unit 116, an output interface unit 117, and a network interface unit 118. The CPU 111, the memory 112, the first disk interface unit 113, the second disk interface unit 114, the display control unit 115, the input interface unit 116, the output interface unit 117, and the network interface unit 118 are connected to each other via a system bus. The auxiliary storage device 121 is connected to the first disk interface unit 113. The optical disk drive 122 is connected to the second disk interface unit 114. The display unit (display device) 123 is connected to the display control unit 115. The keyboard 124 and the mouse 125 are connected to the input interface unit 116. The printing machine main body 200 is connected to the output interface unit 117 via a communication cable. A communication line 5 is connected to the network interface unit 118. The auxiliary storage device 121 is a magnetic disk device or the like. An optical disk 6 as a computer-readable recording medium such as a CD-ROM or a DVD-ROM is inserted into the optical disk drive 122. The display unit 123 is a liquid crystal display or the like. The display unit 123 is used to display information desired by the operator. The keyboard 124 and the mouse 125 are used for an operator to input instructions to the printing control apparatus 100.

[0056] The auxiliary storage device 121 stores a printing control program P (a program for controlling the execution of printing processing by the printer main body 200). The CPU 111 reads out the printing control program P stored in the auxiliary storage device 121 to the memory 112 and executes it, thereby realizing various functions of the printing control device 100. The memory 112 includes a RAM and a ROM. The memory 112 functions as a work area for the CPU 111 to execute the printing control program P stored in the auxiliary storage device 121. Note that the printing control program P is stored and provided in the above computer-readable recording medium (non-transitory recording medium). That is, for example, the user purchases the optical disk 6 as a recording medium for the printing control program P, inserts it into the optical disk drive 122, reads out the printing control program P from the optical disk 6, and installs it in the auxiliary storage device 121. Alternatively, the printing control program P transmitted via the communication line 5 may be received by the network interface unit 118 and installed in the auxiliary storage device 121.

[0057] <1.4 Control Unit> FIG. 6 is a block diagram showing a schematic functional configuration of a control unit 150 realized by executing the printing control program P in the printing control device 100. The control unit 150 generally includes a maintenance content control unit 151, a conveyance control unit 152, a printing control unit 153, a maintenance mechanism control unit 154, a drying control unit 155, and an inspection control unit 156.

[0058] The maintenance content control unit 151 determines the content of maintenance for the printing unit 24 (more specifically, the inkjet head 241) based on the result of inspection by the image inspection device 300 (the inspection result Dr obtained by the image inspection computer 320). A more detailed description of the maintenance content control unit 151 will be given later.

[0059] The conveyance control unit 152 controls the speed (conveyance speed) at which the conveyance mechanism 210 conveys the printing paper PA. In the present embodiment, the conveyance mechanism 210 is realized by the paper delivery unit 21, the first drive roller 22, the plurality of support rollers 23, the second drive roller 27, and the paper winding unit 28 (see FIG. 2).

[0060] The print control unit 153 controls the ejection of ink from each nozzle included in each inkjet head 241 that constitutes the printing unit 24. For example, the ejection timing of the ink and the control of the ejection amount of the ink are performed.

[0061] The maintenance mechanism control unit 154 controls the operation of the maintenance mechanism 250 according to the content of the maintenance determined by the maintenance content control unit 151. In this regard, the maintenance mechanism 250 is composed of a cleaning mechanism 25 that cleans the inkjet head 241 and a flushing mechanism 242 that performs flushing. The flushing mechanism 242 is included in the printing unit 24.

[0062] The drying control unit 155 controls the temperature (drying temperature) when the drying unit 26 dries the printing paper PA. The inspection control unit 156 controls the imaging timing of the printed image by the imaging unit 310.

[0063] <1.5 Control of Maintenance> As described above, the inkjet printing apparatus 10 according to the present embodiment has an auto splice function. In a conventional inkjet printing apparatus, maintenance was not performed when roll paper was replaced using the auto splice function. In contrast, in the inkjet printing apparatus 10 according to the present embodiment, maintenance of the inkjet head 241 is performed when roll paper is replaced using the auto splice function. The control of the maintenance will be described in detail below.

[0064] In the following, the roll paper currently in use (the roll paper that has already been the object of use) is referred to as the "preceding roll paper", the roll paper to be the next object of use is referred to as the "subsequent roll paper", the printing paper in the state of continuous paper unwound from the preceding roll paper is referred to as the "preceding printing paper", and the printing paper in the state of continuous paper unwound from the subsequent roll paper is referred to as the "subsequent printing paper".

[0065] <1.5.1 Functional Configuration Related to Maintenance> Figure 7 is a block diagram showing the functional configuration related to maintenance. In the control unit 150, as components related to maintenance, in addition to the above-described maintenance content control unit 151, printing control unit 153, and maintenance mechanism control unit 154, an inspection result holding unit 157 and a job information holding unit 158 are provided. Further, the printing unit 24, maintenance mechanism 250 (cleaning mechanism 25 and flushing mechanism 242), imaging unit 310, image inspection computer 320, and splicer 213 are related to maintenance.

[0066] When the remaining amount of the preceding roll paper becomes small, a splice trigger signal ST is output from the splicer 213. This splice trigger signal ST is a signal that triggers the replacement of the roll paper. When the printing control unit 153 receives the splice trigger signal ST, it controls the operation of the printing unit 24 so that an inspection pattern for inspecting for defects (such as nozzle defects) is printed at the end of the preceding printing paper. Imaging of the printed image of the inspection pattern is performed by the imaging unit 310, and the captured image data Di obtained by the imaging is sent to the image inspection computer 320. The image inspection computer 320 performs an inspection for detecting defects based on the captured image data Di, and the inspection result Dr is held in the inspection result holding unit 157.

[0067] The job information holding unit 158 holds various types of information (job information JI) such as printing conditions for jobs in a state where printing is reserved. From the splicer 213, paper information PI such as paper type and paper width for the leading roll paper and the trailing roll paper is provided to the maintenance content control unit 151. When the maintenance content control unit 151 receives the splice trigger signal ST, based on the job information JI, the paper information PI, and the defect information LI which is the inspection result regarding defects among the inspection results Dr held in the inspection result holding unit 157, it determines the necessity of maintenance, the inkjet head 241 to be the maintenance target, and the type of maintenance. The maintenance mechanism control unit 154 controls the operations of the cleaning mechanism 25 and the flushing mechanism 242 according to the content determined by the maintenance content control unit 151.

[0068] Incidentally, in the present embodiment, a determination criterion for determining maintenance content including the necessity of maintenance and the specification of the inkjet head 241 to be the maintenance target is provided. For example, the number of defects is used as the determination criterion. In this case, for example, a determination criterion such as "if the number of defects is 3 or more, maintenance is necessary" is defined. Also, the determination criterion varies depending on the paper type, printing conditions, etc. For example, on the premise that the first threshold is larger than the second threshold, when paper that does not require good quality is used, a determination criterion such as "if the number of defects is equal to or more than the first threshold, maintenance is necessary" is defined, whereas when paper that requires good quality is used, a determination criterion such as "if the number of defects is equal to or more than the second threshold, maintenance is necessary" is defined. According to this example, for the same inspection result, when paper that requires good quality is used, the possibility of determining that maintenance is necessary is higher than when paper that does not require good quality is used. Regarding the level of the determination criterion, in this specification, it is assumed that as the determination criterion becomes higher, the possibility of determining that maintenance is necessary becomes higher.

[0069] In addition, in the present embodiment, regarding maintenance when roll paper is replaced using the auto splice function, the identification of the inkjet head 241 to be maintained is performed according to a determination criterion suitable for printing after the roll paper is replaced.

[0070] As described above, when the roll paper to be used is replaced from the preceding roll paper to the succeeding roll paper by the splicer 213, the maintenance content control unit 151 determines the inkjet head 241 to be maintained based on the inspection result Dr obtained from the inspection of the printed image of the inspection pattern (inspection pattern for inspecting defects of the print head including nozzle missing) by the image inspection device 300 according to the determination criterion suitable for printing on the succeeding printing paper (continuous paper unwound from the succeeding roll paper). Note that, for such a case, a function for notifying and storing the determination content when assuming that it is made according to the determination criterion suitable for printing on the preceding printing paper (continuous paper unwound from the preceding roll paper) may be provided.

[0071] <1.5.2 Overall processing flow when roll paper is replaced> With reference to the flowchart shown in FIG. 8, the overall processing flow when roll paper is replaced will be described.

[0072] Under the situation where printing on the preceding printing paper (step S100) is being performed, when the remaining amount of the preceding roll paper becomes slightly less, a splice trigger signal ST is output from the splicer 213 (step S102). Specifically, a threshold value for comparing with the remaining amount of the roll paper is provided, and when the remaining amount of the preceding roll paper becomes equal to or less than the threshold value, a splice trigger signal ST is output from the splicer 213.

[0073] In response to the output of the splice trigger signal ST, the above-described inspection pattern is printed at the end of the preceding printing paper (step S104). Then, an inspection of the printed image of the inspection pattern is performed by the image inspection apparatus 300 (step S106). Regarding this, first, the imaging unit 310 images the printed image obtained by the printing in step S104. Next, the captured image data Di obtained by the imaging by the imaging unit 310 is sent to the image inspection computer 320. Then, in the image inspection computer 320, image analysis of the captured image data Di is performed. As described above, detection of defects is performed based on the printed image of the inspection pattern. Note that since the inspection based on the printed image of the inspection pattern printed at the end of the preceding printing paper is performed in this manner, the inspection result indicating no abnormality guarantees that the printing result of the job executed before the roll paper is replaced is good.

[0074] After the inspection of the printed image of the inspection pattern is completed, based on the inspection result, a process of determining the necessity of maintenance, the inkjet head 241 to be the maintenance target, and the type of maintenance (hereinafter referred to as "maintenance content determination process") is performed (step S110). Then, a determination is made as to whether maintenance is necessary (step S112). As a result, if it is determined that maintenance is necessary, the process proceeds to step S114, and if it is determined that maintenance is not necessary, the process proceeds to step S130. In step S114, maintenance of the inkjet head 241 is performed by the maintenance mechanism 250.

[0075] Also, in parallel with the processes of steps S110 to S114, the roll paper is replaced (step S120). That is, the end portion of the preceding printing paper and the start portion of the subsequent printing paper are joined by the splicer 213, and the roll paper to be used is replaced from the preceding roll paper to the subsequent roll paper. In this way, in step S120, the roll paper is replaced without human intervention.

[0076] In step S130, an inspection pattern is printed on the leading portion of the subsequent printing paper. Then, an inspection of the printed image of the inspection pattern is performed by the image inspection device 300 (step S132).

[0077] Thereafter, based on the inspection result, it is determined whether there is a need to stop printing (step S140). As a result, if it is determined that printing needs to be stopped, the process proceeds to step S142, and if it is determined that printing does not need to be stopped, the process proceeds to step S144. In step S142, printing is stopped. In this case, the conveyance of the subsequent printing paper is stopped, and printing is resumed after, for example, performing cleaning of the inkjet head 241. In step S144, printing on the subsequent printing paper is executed.

[0078] In the present embodiment, the inspection pattern printing step is realized by step S104, the inspection step is realized by step S106, the maintenance content control step is realized by step S110, the maintenance step is realized by step S114, and the roll paper replacement step is realized by step S120.

[0079] <1.5.3 Maintenance Content Determination Process> Next, the maintenance content determination process (step S110 in FIG. 8) will be described in detail. Here, paying attention to the case where the paper width changes before and after the replacement of the roll paper, the printing paper with a wide paper width is referred to as "wide paper", and the printing paper with a narrow paper width is referred to as "narrow paper". The wide paper is labeled with reference numeral 61, and the narrow paper is labeled with reference numeral 62. Also, assume that there are 10 inkjet heads H1 to H10 (hereinafter abbreviated as "head H1" to "head H10"), and the relationship between each of the wide paper 61 and the narrow paper 62 and the heads H1 to H10 is as shown in FIG. 9. The paper width of the wide paper 61 is W1, and the paper width of the narrow paper 62 is W2. When printing on the wide paper 61, heads H1 to H10 are used, and when printing on the narrow paper 62, heads H1 to H7 are used.

[0080] <1.5.3.1 Replacement from Wide Paper to Narrow Paper> While referring to the flowchart shown in FIG. 10, the procedure of the maintenance content determination process when replacing from the wide paper 61 to the narrow paper 62 will be described. This maintenance content determination process is performed by the maintenance content control unit 151. In this case, after the roll paper is replaced, printing on the narrow paper 62 is performed, so the heads H1 to H7 are used. In this example, the heads H1 to H10 correspond to the first printing head group, the heads H1 to H7 correspond to the second printing head group, and the heads H8 to H10 correspond to the third printing head group. Here, it is assumed that there are chips in the heads H8 and H10 among the heads H8 to H10 that become unused after the roll paper is replaced.

[0081] After the start of the maintenance content determination process, first, the inspection result Dr (more specifically, the chip defect information LI among the inspection results Dr) regarding the inspection pattern printed at the end of the preceding printing paper (here, the wide paper 61) is acquired (step S200). Next, the paper information PI, which is information such as the paper type and paper width for each of the preceding printing paper and the subsequent printing paper (here, the narrow paper 62), is acquired (step S210). Further, the job information JI, which is various information such as the printing conditions for the job executed after the roll paper is replaced, is acquired (step S220).

[0082] Next, based on the paper width information obtained in step S210, a head to be used after the roll paper is replaced (hereinafter referred to as the "used head") and a head not to be used after the roll paper is replaced (hereinafter referred to as the "unused head") are identified (step S230). In this case, heads H1 to H7 are identified as used heads, and heads H8 to H10 are identified as unused heads. Then, based on the inspection result Dr obtained in step S200, it is determined whether there is a defect in the used head (step S240). As a result, if there is a defect in the used head, the process proceeds to step S250. On the other hand, if there is no defect in the used head, a decision is made not to perform maintenance, and this maintenance content determination process ends.

[0083] In step S250, it is determined whether maintenance is necessary. Specifically, based on the inspection result Dr obtained in step S200, it is determined whether maintenance of the used heads (heads H1 to H7) is necessary according to the determination criteria (determination criteria suitable for printing on the narrow-width paper 62) defined for printing on the narrow-width paper 62. This determination is made, for example, based on the comparison result between the number of defects, the size of the largest defect, and a threshold value predetermined for the narrow-width paper 62 instead of the wide-width paper 61. As a result, if it is determined that maintenance is necessary, the process proceeds to step S260. On the other hand, if it is determined that maintenance is not necessary, this maintenance content determination process ends. Note that the determination of whether maintenance is necessary in this step S250 is made for the entire used heads (the entire heads H1 to H7), not for each head.

[0084] In step S260, the heads to be subject to maintenance are identified. In this case, the heads with defects among the used heads (heads H1 to H7) and the heads with defects among the unused heads (heads H8 to H10) are determined to be the maintenance targets. If, for example, only head H1 among the used heads (heads H1 to H7) has a defect, then heads H1, H8, and H10 are determined to be the maintenance targets.

[0085] In step S270, based on the inspection result Dr obtained in step S200, it is determined whether cleaning of the maintenance target head is necessary according to the determination criteria defined for printing on the narrow-width paper 62. Similar to step S250, this determination is also made, for example, based on the comparison result between the number of chips, the size of the largest chip, and the threshold value predetermined for the narrow-width paper 62 instead of the wide-width paper 61. As a result, if it is determined that cleaning is necessary, the process proceeds to step S272, and if it is determined that cleaning is not necessary, the process proceeds to step S274. Note that if it is determined that cleaning is not necessary, flushing will be executed. As described above, the type of maintenance is determined according to the determination criteria suitable for printing on the subsequent printing paper (here, the narrow-width paper 62).

[0086] In step S272, the intensity of cleaning (cleaning intensity) when performing cleaning is determined. Regarding this, for example, past inspection results may be saved, and the cleaning intensity may be determined based on the immediately preceding inspection result and the past inspection results. Also, the cleaning intensity is determined according to the judgment criteria suitable for printing on the subsequent printing paper (here, the narrow-width paper 62).

[0087] In step S274, the content of flushing is determined. Regarding this, for example, the flushing amount and the number of flushing sheets (sheets printed with a special pattern for improving chips) are determined. The content of flushing is also determined according to the judgment criteria suitable for printing on the subsequent printing paper (here, the narrow-width paper 62).

[0088] As described above, in this example, only regarding the used heads, the print heads to be maintained and the maintenance contents (e.g., cleaning intensity and flushing contents) are determined according to the criteria suitable for printing on subsequent printing paper. Regarding the unused heads, it is as follows. When there is a shortage in the used heads and it is determined in step S250 that maintenance is necessary, the unused heads are included in the heads to be maintained. On the contrary, when there is no shortage in the used heads or it is determined in step S250 that maintenance is not necessary, the maintenance of the unused heads is not performed.

[0089] <1.5.3.2 Replacement from Narrow Paper to Wide Paper> With reference to the flowchart shown in FIG. 11, the procedure of the maintenance content determination process when replacing from the narrow paper 62 to the wide paper 61 will be described. In this case, after the roll paper is replaced, printing on the wide paper 61 is performed, so the heads H1 to H10 are used. In this example, the heads H1 to H10 correspond to the fourth print head group, the heads H1 to H7 correspond to the fifth print head group, and the heads H8 to H10 correspond to the sixth print head group.

[0090] After the start of the maintenance content determination process, first, the inspection result Dr of the inspection pattern printed at the end of the preceding printing paper (here, the narrow paper 62), more specifically, the defect information LI which is the inspection result regarding the defect among the inspection results Dr, is acquired (step S300). Since the narrow paper 62 corresponds to the heads H1 to H7, the inspection results for the areas corresponding to the heads H8 to H10 cannot be obtained. In step S310, the paper information PI is acquired in the same manner as step S210 in FIG. 10, and in step S320, the job information JI is acquired in the same manner as step S220 in FIG. 10.

[0091] Next, based on the paper width information obtained in step S310, the heads that were used before the roll paper replacement (hereinafter referred to as "used heads") and the heads that were not used before the roll paper replacement (hereinafter referred to as "unused heads") are identified (step S330). In this case, heads H1 to H7 are identified as used heads, and heads H8 to H10 are identified as unused heads.

[0092] Thereafter, it is determined whether maintenance of the used heads is necessary (step S340). Specifically, based on the inspection result Dr obtained in step S300, it is determined whether maintenance of the used heads (heads H1 to H7) is necessary according to the determination criteria defined for printing on the wide paper 61 (the determination criteria suitable for printing on the wide paper 61). As a result, if it is determined that maintenance is necessary, the process proceeds to step S342, and if it is determined that maintenance is not necessary, the process proceeds to step S344.

[0093] In step S342, the heads with chips among the used heads (heads H1 to H7) and all the unused heads (heads H8 to H10) are determined to be maintenance targets. If, for example, only head H1 among the used heads (heads H1 to H7) has a chip, then head H1 and heads H8 to H10 are determined to be maintenance targets.

[0094] In step S344, all the unused heads (heads H8 to H10) are determined to be maintenance targets.

[0095] In step S350, based on the inspection result Dr obtained in step S300, it is determined whether cleaning of the maintenance target heads is necessary according to the determination criteria defined for printing on the wide paper 61. As a result, if it is determined that cleaning is necessary, the process proceeds to step S352, and if it is determined that cleaning is not necessary, the process proceeds to step S354.

[0096] In step S352, the cleaning intensity is determined in the same manner as step S272 in FIG. 10, and in step S354, the content of the flushing is determined in the same manner as step S274 in FIG. 10.

[0097] As described above, in this example, for the used heads only, the print head to be maintained is determined according to the determination criteria suitable for printing on the subsequent print paper. For the unused heads, regardless of the necessity of maintenance of the used heads, they are to be maintained.

[0098] <1.6 Effect> According to the present embodiment, the control unit 150 of the inkjet printing apparatus 10 having the auto splice function is provided with a maintenance content control unit 151 that determines the necessity of maintenance of the inkjet head 241, the inkjet head 241 to be maintained, and the type of maintenance, and a maintenance mechanism control unit 154 that controls the operations of the cleaning mechanism 25 and the flushing mechanism 242 according to the content determined by the maintenance content control unit 151. When the roll paper to be used is replaced by the splicer 213, the maintenance content control unit 151 determines the inkjet head 241 to be maintained according to the determination criteria suitable for printing on the subsequent print paper based on the inspection results of the inspection pattern. Thereby, when the roll paper is replaced, the maintenance of the inkjet head 241 is performed according to the print process to be executed after the replacement. As described above, according to the present embodiment, the inkjet printing apparatus 10 capable of performing suitable maintenance in consideration of the print process planned to be executed after the replacement when the roll paper having the auto splice function is replaced is realized.

[0099] Further, according to the present embodiment, when switching from the wide paper 61 to the narrow paper 62, if there is no defect in the inkjet head 241 used after the roll paper is replaced, or if there is a defect in the inkjet head 241 used after the roll paper is replaced but maintenance of these inkjet heads 241 is not necessary, maintenance is not performed on any of the inkjet heads 241. As a result, it is possible to suppress the execution of maintenance more than necessary, and shorten the printing time.

[0100] Furthermore, according to the present embodiment, when switching from the narrow paper 62 to the wide paper 61, all the inkjet heads 241 that were not used before the roll paper is replaced are determined to be maintenance targets. In this way, since the inkjet heads 241 that change from the unused state to the used state before and after the roll paper replacement are surely maintained, the occurrence of ejection failure of the inkjet heads 241 that were in the unused state is effectively suppressed.

[0101] Furthermore, according to the present embodiment, cleaning and flushing are prepared as types of maintenance for the inkjet head 241. By appropriately differentiating between cleaning and flushing, it is possible to suppress a decrease in printing efficiency while maintaining print quality.

[0102] <1.7 Modification Example> In the description of the above embodiment, attention was paid to the case where the paper width changes before and after the roll paper is replaced. However, the present invention can also be applied to other cases. Therefore, a case where double-sided printing and single-sided printing are switched before and after the roll paper is replaced will be described as a first modification example, and a case where color printing and monochrome printing are switched before and after the roll paper is replaced will be described as a second modification example. In the description of this modification example, the inkjet head is abbreviated as "head".

[0103] <1.7.1 First Modification Example> FIG. 12 is a schematic diagram showing a configuration example of the inkjet printing apparatus 10 in this modified example. In this modified example, the printing machine main body 200 includes a paper feeding unit 21 that supplies printing paper (roll paper), a first printing mechanism 20a that performs printing on the front surface of the printing paper, a reversing unit 29 that reverses the front and back surfaces of the printing paper output from the first printing mechanism 20a, a second printing mechanism 20b that performs printing on the back surface of the printing paper, and a paper winding unit 28 that winds up the printed paper after printing. The internal configuration of the first printing mechanism 20a and the second printing mechanism 20b is the same as the internal configuration of the printing mechanism 20 in the above embodiment. As described above, since printing can be performed on both the front surface and the back surface of the printing paper, it is also possible to switch between double-sided printing and single-sided printing.

[0104] When single-sided printing is executed, ink ejection from the printing unit to the printing paper is stopped in either the first printing mechanism 20a or the second printing mechanism 20b. That is, when double-sided printing is executed, both heads of the first printing mechanism 20a and the second printing mechanism 20b are used, whereas when single-sided printing is executed, only one of the heads of either the first printing mechanism 20a or the second printing mechanism 20b is used. Thus, when single-sided printing is executed, a part of the plurality of heads used when double-sided printing is executed is used. Therefore, "switching from double-sided printing to single-sided printing" before and after the replacement of the roll paper corresponds to "replacement from the wide paper 61 to the narrow paper 62" in the first embodiment, and "switching from single-sided printing to double-sided printing" before and after the replacement of the roll paper corresponds to "replacement from the narrow paper 62 to the wide paper 61" in the first embodiment.

[0105] When switching from double-sided printing to single-sided printing before and after the roll paper is replaced, the maintenance content determination process is executed in the same procedure as when "replacing the wide paper 61 with the narrow paper 62" in the first embodiment (see Fig. 10). As a result, when there is no chip in the head used for single-sided printing and it is determined that maintenance is not necessary according to the judgment criteria suitable for single-sided printing for the head used for single-sided printing, no head maintenance is performed when replacing the roll paper. On the other hand, when there is a chip in the head used for single-sided printing and it is determined that maintenance is necessary according to the judgment criteria suitable for single-sided printing for the head used for single-sided printing, maintenance is performed on the head with a chip among the plurality of heads used for single-sided printing and on the head with a chip among the plurality of heads used for both single-sided printing and double-sided printing. In this example, the set of heads used for double-sided printing corresponds to the first printing head group, the set of heads used for single-sided printing corresponds to the second printing head group, and the set of heads used only when double-sided printing is performed corresponds to the third printing head group.

[0106] When switching from single-sided printing to double-sided printing before and after replacing the roll paper, the maintenance content determination process is executed in the same procedure as in the case of "replacing the narrow-width paper 62 with the wide-width paper 61" in the first embodiment (see Fig. 11). As a result, when it is determined that maintenance is necessary for the heads used for single-sided printing according to the criteria suitable for double-sided printing, maintenance is performed on the heads with chips among the multiple heads used for single-sided printing, and maintenance is performed on all the heads used for both single-sided printing and double-sided printing. On the other hand, when it is determined that maintenance is not necessary for the heads used for single-sided printing according to the criteria suitable for double-sided printing, only maintenance is performed on all the heads used for both single-sided printing and double-sided printing. In this example, the set of heads used for double-sided printing corresponds to the fourth printing head group, the set of heads used for single-sided printing corresponds to the fifth printing head group, and the set of heads used only when double-sided printing is performed corresponds to the sixth printing head group.

[0107] As described above, also according to this modification example, in the inkjet printing apparatus 10 having the auto splice function, when the roll paper is replaced, suitable maintenance considering the printing process scheduled to be executed after the replacement is performed.

[0108] <1.7.2 Second Modification Example> When the printing unit 24 having the configuration shown in Fig. 3 is adopted, for monochrome printing, there are cases where only K-color ink is used and cases where C-color ink, M-color ink, Y-color ink, and K-color ink are used. However, in this modification example, it is assumed that only K-color ink is used when monochrome printing is executed.

[0109] Regarding color printing, C ink, M ink, Y ink, and K ink are used. That is, when color printing is performed, a head for discharging C ink (hereinafter referred to as the "C-color head"), a head for discharging M ink (hereinafter referred to as the "M-color head"), a head for discharging Y ink (hereinafter referred to as the "Y-color head"), and a head for discharging K ink (hereinafter referred to as the "K-color head") are used. In this modification, when monochrome printing is performed, only the K-color head is used. Thus, when monochrome printing is performed, some of the plurality of heads used when color printing is performed are used. Therefore, the "switching from color printing to monochrome printing" before and after the roll paper replacement corresponds to the "replacement from the wide paper 61 to the narrow paper 62" in the first embodiment, and the "switching from monochrome printing to color printing" before and after the roll paper replacement corresponds to the "replacement from the narrow paper 62 to the wide paper 61" in the first embodiment.

[0110] When switching from color printing to monochrome printing before and after the roll paper replacement, the maintenance content determination process is executed in the same procedure as in the case of the "replacement from the wide paper 61 to the narrow paper 62" in the first embodiment (see FIG. 10). As a result, when there is no shortage in the K-color head and it is determined that maintenance is not necessary according to the determination criteria suitable for monochrome printing for the K-color head, no head maintenance is performed during the roll paper replacement. On the other hand, when there is a shortage in the K-color head and it is determined that maintenance is necessary according to the determination criteria suitable for monochrome printing for the K-color head, maintenance is performed on the head with the shortage among the plurality of K-color heads and on the heads with the shortage among the plurality of C-color heads, the plurality of M-color heads, and the plurality of Y-color heads. In this example, the set of heads used for color printing corresponds to the first printing head group, the set of heads used for monochrome printing corresponds to the second printing head group, and the set of heads used only when color printing is performed corresponds to the third printing head group.

[0111] When switching from monochrome printing to color printing before and after the roll paper is replaced, the maintenance content determination process is executed in the same procedure as in the case of "replacement from the narrow-width paper 62 to the wide-width paper 61" in the first embodiment (see FIG. 11). Thus, when it is determined that maintenance is necessary for the K-color heads according to the determination criteria suitable for color printing, maintenance is performed on the heads with chips among the plurality of K-color heads, and maintenance is performed on all C-color heads, all M-color heads, and all Y-color heads. On the other hand, when it is determined that maintenance is not necessary for the K-color heads according to the determination criteria suitable for color printing, maintenance is performed on all C-color heads, all M-color heads, and all Y-color heads. In this example, the set of heads used for color printing corresponds to the fourth printing head group, the set of heads used for monochrome printing corresponds to the fifth printing head group, and the set of heads used only when color printing is performed corresponds to the sixth printing head group.

[0112] Note that when switching from monochrome printing to color printing before and after the roll paper is replaced, an inspection pattern may be printed at the end of the printing paper for monochrome printing, which is the preceding printing paper, using the C-color head, M-color head, Y-color head, and K-color head. In this case, inspection patterns of C color, M color, Y color, and K color are formed on the printing paper for monochrome printing. Then, these inspection patterns are read, and the maintenance content for the heads that require maintenance and the heads that require maintenance for the colors based on the reading result of the inspection pattern may be determined. By executing such control, during the period of executing printing on the preceding printing paper, it is possible to determine the necessity and content of maintenance for each head according to the determination criteria suitable for printing on the subsequent printing paper. Therefore, printing can be surely performed with high print quality from the leading portion of the subsequent printing paper.

[0113] As described above, also in this modified example, in the inkjet printing apparatus 10 having the auto splice function, when the roll paper is replaced, suitable maintenance is executed in consideration of the printing process scheduled to be executed after the replacement.

[0114] Note that the second modified example was about the case of switching between color printing and monochrome printing before and after the replacement of the roll paper, but the same control can be adopted for the case of switching between printing using a special head and printing not using a special head before and after the replacement of the roll paper. For example, when switching from normal color printing that does not use a special feature to color printing that uses a special feature, an inspection pattern is printed at the end of the printing paper for normal color printing, which is the preceding printing paper, using the normal C, M, Y, K color heads and the special feature head used for the subsequent printing paper. Then, the inspection patterns of C, M, Y, K colors and the special feature are read, and based on the read results, the maintenance content for the heads of the colors that require maintenance and the heads of the colors that require maintenance may be determined.

[0115] <2. Second Embodiment> <2.1 Outline and Configuration> In an inkjet printing apparatus, continuous printing based on a plurality of jobs may be executed. When continuous printing is being executed, a plurality of jobs may be the printing targets between the replacement of the roll paper and the next replacement of the roll paper. Also, the criteria used for determining the content of maintenance (necessity of maintenance, inkjet heads 241 to be the maintenance targets, type of maintenance, etc.) may be determined for each job. Therefore, an embodiment assuming that the criteria are determined for each job and continuous printing based on a plurality of jobs is executed will be described as the second embodiment.

[0116] In the present embodiment, when determining the content of maintenance to be performed when the roll paper to be used is replaced from the preceding roll paper to the succeeding roll paper, among the determination criteria defined for a plurality of jobs for which printing is scheduled to be performed until the roll paper to be used is replaced from the further succeeding roll paper to the next roll paper, the strictest determination criterion (the determination criterion for which the number of inkjet heads 241 determined to be maintenance targets becomes the largest) is used.

[0117] The overall configuration of the printing system, the configuration of the inkjet printing apparatus 10, the configuration of the printing unit 24, the configuration related to the auto splice function, the hardware configuration of the printing control apparatus 100, the schematic functional configuration of the control unit 150, and the functional configuration related to maintenance are the same as those in the first embodiment described above, and thus the description thereof is omitted (see FIGS. 1 to 7).

[0118] <2.2 Maintenance Control> Hereinafter, the maintenance control in the present embodiment will be described. Here, as shown in FIG. 13, attention is paid to the maintenance performed at the time of the first roll paper replacement in the case where the first roll paper replacement is performed at time t1 and the second roll paper replacement is performed at time t2. In this regard, it is assumed that printing based on job (C), job (D), and job (E) is scheduled to be performed from the time of the first roll paper replacement until the time of the second roll paper replacement. In the portion marked with reference numeral 71 in FIG. 13, the level of the determination criterion for each job is numerically indicated, and it is assumed that the higher the numerical value, the higher the possibility of being determined to require maintenance.

[0119] According to FIG. 13, the level of the determination criterion for job (C) is 2, the level of the determination criterion for job (D) is 3, and the level of the determination criterion for job (E) is 1. The strictest determination criterion among the determination criteria for these three jobs is the determination criterion for job (D). Therefore, in the example shown in FIG. 13, according to the determination criterion for job (D), the content of the maintenance to be performed at the time of the first roll paper replacement is determined.

[0120] With reference to the flowchart shown in FIG. 14, the procedure of the maintenance content determination process in this embodiment will be described. Also in this embodiment, the maintenance content determination process is performed by the maintenance content control unit 151.

[0121] After the start of the maintenance content determination process, first, the inspection result Dr for the inspection pattern printed at the end of the preceding printing paper is acquired (step S400).

[0122] Thereafter, job information JI regarding a group of jobs (a plurality of jobs) to be executed until the roll paper is replaced next is acquired (step S410). Here, job information JI regarding a group of jobs for which printing is scheduled to be executed from the first roll paper replacement until the second roll paper replacement is acquired. That is, job information JI regarding jobs (C), (D), and (E) is acquired. Note that the job information JI includes information such as printing conditions.

[0123] Next, the level of the determination criterion for each job is acquired based on the job information JI, and the maximum level among the acquired levels is specified (step S420). Here, the level of the determination criterion for each of jobs (C), (D), and (E) is acquired, and 3, which is the level of the determination criterion for job (D), is specified as the maximum level.

[0124] Next, it is determined whether maintenance is necessary (step S430). Specifically, based on the inspection result Dr obtained in step S400, for example, whether maintenance of the inkjet head 241 used in printing based on job (C), job (D), and job (E) is necessary is determined according to the determination criteria for job (D). As a result, if it is determined that maintenance is necessary, the process proceeds to step S440. On the other hand, if it is determined that maintenance is not necessary, a decision is made not to perform maintenance, and this maintenance content determination process ends.

[0125] In step S440, the inkjet head 241 to be maintained is specified. For example, among the inkjet heads 241 used in printing based on job (C), job (D), and job (E), the inkjet head 241 with a chip is determined to be the maintenance target.

[0126] Thereafter, based on the inspection result Dr obtained in step S400, whether cleaning of the inkjet head 241 to be maintained is necessary is determined according to the determination criteria for job (D). As a result, if it is determined that cleaning is necessary, the process proceeds to step S452, and if it is determined that cleaning is not necessary, the process proceeds to step S454. Note that if it is determined that cleaning is not necessary, flushing will be executed.

[0127] In step S452, the cleaning intensity is determined in the same manner as step S272 in FIG. 10, and in step S454, the content of flushing is determined in the same manner as step S274 in FIG. 10.

[0128] <2.3 Effects> According to this embodiment, in the inkjet printing apparatus 10 having an auto splice function, when the roll paper to be used is replaced by the splicer 213, the maintenance content control unit 151 determines the inkjet head 241 to be maintained according to the strictest determination criterion among the determination criteria defined for a plurality of jobs for which printing is scheduled before the next roll paper replacement. Thereby, when the roll paper is replaced, maintenance of the inkjet head 241 is performed according to the printing process to be executed after the replacement. As described above, similar to the first embodiment, also according to this embodiment, an inkjet printing apparatus 10 capable of performing suitable maintenance in consideration of the printing process scheduled to be executed after replacement when the roll paper is replaced and having an auto splice function is realized.

[0129] <3. Others> The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiments, either cleaning or flushing is performed as maintenance for the printing unit 24, but the present invention is not limited to this, and both cleaning and flushing may be performed as maintenance for the printing unit 24.

Explanation of Reference Numerals

[0130] 10… Inkjet printing apparatus 24… Printing unit 25… Cleaning mechanism 100… Printing control apparatus 150… Control unit 151… Maintenance content control unit 153… Printing control unit 154… Maintenance mechanism control unit 157… Inspection result holding unit 158… Job information holding unit 200… Printing machine main body 213… Splicer 241… Inkjet head 242… Flushing mechanism 250…Maintenance mechanism 300…Image inspection device 310…Imaging unit 320…Image inspection computer ST…Splice trigger signal

Claims

1. A printing unit including a print head that performs printing by discharging ink onto continuous paper unwound from a roll of paper; A print control unit that controls the operation of the printing unit; A maintenance mechanism that performs maintenance on the print head; An inspection device that inspects a printed image obtained by printing by the printing unit; A maintenance content control unit that determines maintenance content for the print head; A maintenance mechanism control unit that controls the operation of the maintenance mechanism so that maintenance of the maintenance content determined by the maintenance content control unit is performed on the print head; A splice unit that joins the end of a preceding roll of paper that has already been the object of use and the start of a subsequent roll of paper that will be the next object of use, and exchanges the roll of paper to be used from the preceding roll of paper to the subsequent roll of paper and comprising When the roll of paper to be used is exchanged from the preceding roll of paper to the subsequent roll of paper by the splice unit, the print control unit controls the operation of the printing unit so that an inspection pattern is printed at the end of the continuous paper unwound from the preceding roll of paper, the maintenance content control unit determines the maintenance content for the print head according to determination criteria suitable for printing on the continuous paper unwound from the subsequent roll of paper, based on the inspection results obtained by inspection of the printed image of the inspection pattern by the inspection device. A printing apparatus characterized by that.

2. When a part of a first print head group, which is a set of print heads used before the roll paper is exchanged by the splice unit, becomes unused after the roll paper is exchanged by the splice unit, the maintenance content control unit The printing apparatus according to claim 1, wherein the maintenance content is determined according to determination criteria suitable for printing on the continuous paper unwound from the subsequent roll of paper only for a second print head group, which is a set of print heads used after the roll paper is exchanged by the splice unit, among the print heads.

3. In the inspection by the inspection device, detection of defects in the print head is performed, If the second print head group does not include a print head in which a defect has been detected by the inspection by the inspection device, the maintenance content control unit determines that none of the print heads are to be the object of maintenance. The printing apparatus according to claim 2, characterized by that.

4. If the second print head group includes a print head in which a defect has been detected by the inspection by the inspection device, the maintenance content control unit determines whether maintenance of the second print head group is necessary. If it is determined that maintenance of the second print head group is necessary, it is determined that the print head in which a defect has been detected by the inspection by the inspection device among the second print head group and the print head that becomes unused after replacement of the roll paper by the splicing unit, which is a set of the third print head group, will be the maintenance targets. If it is determined that maintenance of the second print head group is not necessary, it is determined that none of the print heads will be the maintenance targets. The printing apparatus according to claim 2, characterized in that.

5. The printing apparatus according to any one of claims 2 to 4, characterized in that the paper width of the subsequent roll paper is narrower than the paper width of the preceding roll paper.

6. The first print head group is a set of print heads used for color printing, The printing apparatus according to any one of claims 2 to 4, characterized in that the second print head group is a set of print heads used for monochrome printing.

7. The first print head group is a set of print heads used for double-sided printing, The printing apparatus according to any one of claims 2 to 4, characterized in that the second print head group is a set of print heads used for single-sided printing.

8. The fourth print head group, which is a set of print heads used after replacement of the roll paper by the splicing unit, is composed of the fifth print head group, which is a set of print heads that were used before replacement of the roll paper by the splicing unit, and the sixth print head group, which is a set of print heads that were not used before replacement of the roll paper by the splicing unit. The printing apparatus according to claim 1, characterized in that the maintenance content control unit determines that all the print heads included in the sixth print head group will be the maintenance targets.

9. The printing apparatus according to claim 8, characterized in that the maintenance content control unit determines, only with respect to the fifth print head group, the print heads to be the maintenance targets according to the determination criteria suitable for printing on the continuous paper unwound from the subsequent roll paper.

10. The printing apparatus according to claim 8 or 9, characterized in that the paper width of the subsequent roll paper is wider than the paper width of the preceding roll paper.

11. The fifth printing head group is a set of printing heads used for monochrome printing, The printing apparatus according to claim 8 or 9, characterized in that the fourth printing head group is a set of printing heads used for color printing.

12. The fifth printing head group is a set of printing heads used for single-sided printing, The printing apparatus according to claim 8 or 9, characterized in that the fourth printing head group is a set of printing heads used for double-sided printing.

13. The determination criteria are determined for each job, The maintenance content control unit determines, according to the determination criteria in which the number of printing heads determined to be maintenance targets is the largest among the determination criteria determined for a plurality of jobs in which printing by the printing unit is scheduled to be executed from when the roll paper to be used is replaced by the splicing unit from the preceding roll paper to the subsequent roll paper until the roll paper to be used is further replaced by the splicing unit from the subsequent roll paper to the next roll paper, the printing heads to be maintenance targets. The printing apparatus according to claim 1.

14. The printing control unit controls the operation of the printing unit so that an inspection pattern is printed at the head of the continuous paper unwound from the subsequent roll paper, The maintenance content control unit further determines whether to stop printing by the printing unit on the continuous paper unwound from the subsequent roll paper based on the inspection result obtained from the inspection of the printed image of the inspection pattern printed at the head of the continuous paper unwound from the subsequent roll paper by the inspection device. The printing apparatus according to any one of claims 1 to 13.

15. As types of maintenance for the printing heads, cleaning and flushing are provided, The maintenance content control unit further determines the type of maintenance to be executed according to the determination criteria suitable for printing on the continuous paper unwound from the subsequent roll paper. The printing apparatus according to any one of claims 1 to 14.

16. When the remaining amount of the preceding roll paper becomes equal to or less than a predetermined threshold value, the splicing unit outputs a splice trigger signal serving as a trigger for roll paper replacement. The printing control unit controls the operation of the printing unit so that an inspection pattern is printed at the end of the continuous paper unwound from the preceding roll paper based on the splice trigger signal. The printing apparatus according to any one of claims 1 to 15.

17. A maintenance method for a printing apparatus including a printing unit including a print head that performs printing by discharging ink onto a continuous paper unwound from a roll paper, and a splice unit that joins a terminal end of a preceding roll paper that has already been used and a start end of a succeeding roll paper that is to be used next and exchanges the roll paper to be used from the preceding roll paper to the succeeding roll paper, An inspection pattern printing step in which the printing unit prints an inspection pattern at the end of the continuous paper unwound from the preceding roll paper; An inspection step of inspecting a printed image of the inspection pattern; A roll paper replacement step in which the splice unit replaces the roll paper to be used from the preceding roll paper to the succeeding roll paper; A maintenance content control step of determining maintenance content for the print head according to a determination criterion suitable for printing on the continuous paper unwound from the succeeding roll paper based on the inspection result obtained in the inspection step in the inspection step; A maintenance step of performing maintenance of the maintenance content determined in the maintenance content control step on the print head A maintenance method for a printing apparatus, characterized by including.

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