Printing device and maintenance method thereof

Abstract

To provide a printer which can reduce a work load related to maintenance of an operator and efficiently execute maintenance.SOLUTION: After termination of printing based on each job, a print control unit 153 controls an operation of a print unit 24 so as to print an inspection pattern on a print sheet in a period in which a conveyance speed of the print sheet is maintained at a constant speed by a conveyance control unit 152. A maintenance content determination unit 151 determines the content of maintenance to the print unit 24 on the basis of an inspection result obtained in an inspection of the print image for the inspection pattern. The print control unit 153 controls operations of the print unit 24 and a cleaning mechanism 25 according to the content of the maintenance determined by the maintenance content determination unit 151.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a printing device and a maintenance method thereof. [Background technology]

[0002] Inkjet printing devices that perform printing by ejecting ink onto a substrate (printing medium) such as printing paper have been known for some time. In inkjet printing devices, when the ejection interval becomes long, the ink may dry out due to evaporation of the solvent near the nozzle during printing, air bubbles may get into the nozzle, and dust may adhere to the nozzle. When such phenomena occur, normal ejection may not be possible, which may result in poor printing. Therefore, maintenance is performed from time to time to avoid such problems.

[0003] Maintenance can be broadly divided into cleaning, which involves wiping the nozzle surface of the inkjet head (print head) using a dedicated mechanism (wiping off dirt), and flushing, which involves forcibly ejecting ink unrelated to the print content. Flushing can be performed while the print paper is being transported, but cleaning must be performed while the print paper is stopped being transported. There are various flushing methods, including star flushing (discrete flushing), which ejects ink thinly over the entire page to be printed, and line flushing, which ejects ink simultaneously from multiple nozzles over a specific line on a page. In the following, acceleration and deceleration of the print paper transport speed will be simply referred to as "acceleration" and "deceleration", respectively.

[0004] Regarding the above-mentioned maintenance, Japanese Patent Application Laid-Open No. 2012-45854 describes a method of printing a test pattern when accelerating before printing starts and when decelerating after printing ends, and performing maintenance based on the results obtained by reading the printed test pattern with a scanner. Japanese Patent Application Laid-Open No. 2017-24287 describes a method of performing star flushing with a relatively large amount of ink ejection when accelerating before printing starts, and performing star flushing with a relatively small amount of ink ejection during printing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-45854 A [Patent Document 2] JP 2017-24287 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, the necessity of performing cleaning has been determined based on the results obtained by printing a test pattern before executing a job (executing printing) and reading the printed test pattern with a scanner. This work is performed by an operator, but it places a heavy burden on the operator. In addition, since it is difficult for an operator to identify inkjet heads that are prone to defects (faults) such as missing nozzles, it is conceivable that the operator will perform cleaning more than necessary. As described above, cleaning cannot be performed unless the transport of printing paper is stopped, so if cleaning is performed more than necessary, printing efficiency will decrease.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a printing device that reduces the workload of an operator in performing maintenance and enables maintenance to be performed efficiently. [Means for solving the problem]

[0008] The first aspect of the present invention includes a conveying mechanism for conveying a print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, and when chipping is detected consecutively a predetermined number of times for the same print head based on the inspection results obtained by the inspection device, the maintenance content determination unit includes, in the maintenance content for the printing unit, a content to increase the flushing amount when flushing is performed compared to the flushing amount when flushing was performed previously. A second aspect of the present invention is a printing apparatus including: a conveying mechanism for conveying a print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, and when chipping is detected a predetermined number of times consecutively for the same print head based on the inspection results obtained by the inspection device, the maintenance content determination unit includes, in the maintenance content for the printing unit, a content of using a larger number of flushing sheets when performing flushing than the number of flushing sheets used when the previous flushing was performed. A third aspect of the present invention includes a conveying mechanism for conveying a print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, the printing control unit controls the operation of the printing unit so that flushing of the printing unit is performed during the period when the transport control unit is accelerating the printing medium. A fourth aspect of the present invention is a printing medium conveying device comprising: a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; a monitoring unit for detecting an event that requires printing to be interrupted; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the print control unit controls an operation of the print unit so that a second test pattern is printed as the test pattern during a period in which the transport speed is maintained at the constant speed; the second test pattern is printed after a main image based on a job to be processed is printed; the print control unit controls the operation of the print unit so that, when the monitoring unit detects an event that requires printing to be interrupted, the second test pattern is printed next to the sheet being printed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance content determination unit, after the monitoring unit detects an event that requires printing to be interrupted, Based on the inspection result obtained by the inspection device inspecting the printed image of the second test pattern, A printing device, characterized in that the content of maintenance for the printing unit is determined. The fifth invention relates to the fourth invention, The print control unit prints a first test pattern as the test pattern during a period in which the transport speed is maintained at the constant speed. N Controlling the operation of the printing unit to print; The first test pattern is The above The image is printed before the actual image based on the job being processed is printed. R It is characterized by: The sixth invention is a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; a monitoring unit for detecting an event that requires printing to be interrupted; a printing medium supply section for supplying the printing medium to the printing section; and Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; the maintenance content determination unit determines the content of maintenance to be performed on the printing unit after the monitoring unit detects an event that requires printing to be interrupted; The monitoring unit detects an event in which the amount of printing media remaining in the printing media supply unit falls below a predetermined value as an event in which printing should be interrupted. , printing device .

[0009] No. 7 The invention is Any of 1 to 6 In the invention, The maintenance content determination unit further determines whether or not execution of maintenance on the printing unit is necessary.

[0013] No. 8 The invention is 1st to 3rd and 7th In any one of the above-mentioned inventions, When the maintenance content determined by the maintenance content determination unit is cleaning, the printing control unit controls the operation of the printing unit and the cleaning mechanism so that cleaning of the printing unit is performed during the period when the transport control unit maintains the transport speed at 0.

[0016] The ninth invention is 1st to 3rd, 7th and 8th In any one of the above-mentioned inventions, the print control unit controls an operation of the print unit so that a first test pattern and a second test pattern are printed as the test patterns during a period in which the transport speed is maintained at the constant speed; the first test pattern is printed before a main image based on a job to be processed is printed; The second test pattern is characterized in that it is printed either after the main image based on the job to be processed has been printed, after the printing of the main image has been interrupted, or after the printing of the main image has been stopped.

[0017] A tenth aspect of the present invention is a printing apparatus including: a conveying mechanism for conveying a print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit and transmits cleaning information; a cleaning history storage unit that accumulates the cleaning information transmitted from the maintenance content determination unit as a cleaning history; Equipped with The cleaning strength at the time when the cleaning mechanism performed the previous cleaning can be known by referring to the cleaning history, the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern and the cleaning history; the content of the maintenance determined by the maintenance content determination unit includes a cleaning strength when the cleaning mechanism cleans the printing unit; A printing device, characterized in that the print control unit controls operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit.

[0022] An eleventh aspect of the present invention is a maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, and a print control unit that controls the operation of the printing unit and the cleaning mechanism, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that, when the maintenance content determined in the maintenance content determination step is flushing, and when chipping is detected a predetermined number of times consecutively for the same print head based on the inspection results obtained in the inspection step, the maintenance content for the printing unit in the maintenance content determination step includes a content that the amount of flushing when flushing is performed is greater than the amount of flushing when flushing was performed previously. A twelfth aspect of the present invention is a maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, and a print control unit that controls the operation of the printing unit and the cleaning mechanism, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that, when the maintenance content determined in the maintenance content determination step is flushing, and when a predetermined number of consecutive defects are detected for the same print head based on the inspection results obtained in the inspection step, the maintenance content for the printing unit in the maintenance content determination step includes a content of increasing the number of flushing sheets when performing flushing compared to the number of flushing sheets used when the previous flushing was performed. A thirteenth aspect of the present invention is a maintenance method for a printing device including a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, a print control unit that controls the operation of the printing unit and the cleaning mechanism, a transport mechanism that transports the printing medium, and a transport control unit that controls a transport speed at which the transport mechanism transports the printing medium, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that when the maintenance content determined in the maintenance content determination step is flushing, the printing control unit controls the operation of the printing unit so that flushing of the printing unit is performed during the period when the transport control unit is accelerating the printing medium. The fourteenth aspect of the present invention is a printer including a printing unit including a plurality of print heads that print on a printing medium by ejecting ink, and a cleaning mechanism that cleans the printing unit. A print control unit that controls the operation of the print unit; A maintenance method for a printing device having a monitoring unit for detecting an event that requires printing to be interrupted, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step after an event that requires printing to be interrupted is detected by the monitoring unit; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including fruit, the print control unit controls an operation of the printing unit so that a second test pattern is printed as the test pattern during a period in which the print medium is transported at the constant speed in the test pattern printing step; the second test pattern is printed after a main image based on a job to be processed is printed; the print control unit controls the operation of the print unit so that, when the monitoring unit detects an event that requires printing to be interrupted, the second test pattern is printed next to the sheet being printed; In the maintenance content determination step, the content of the maintenance for the printing unit is determined based on an inspection result obtained by inspecting a printed image of the second inspection pattern in the inspection step. A maintenance method for a printing device. A fifteenth aspect of the present invention is a maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, and a cleaning mechanism that cleans the printing unit, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit and accumulating cleaning information as a cleaning history; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The cleaning strength at the time when the cleaning mechanism performed the previous cleaning can be known by referring to the cleaning history, In the maintenance content determination step, the content of maintenance for the printing unit is determined based on an inspection result obtained by inspecting the printed image in the inspection step and the cleaning history. 、 The content of the maintenance determined in the maintenance content determination step includes a cleaning strength when the cleaning mechanism cleans the printing unit. A maintenance method for a printing device. Effect of the Invention

[0023] Above 1 to 4 and Article 6 above.According to the invention, the maintenance content for the printing unit is determined by the maintenance content determination unit. Since the maintenance content is determined without the need for the operator's judgment, the workload of the operator related to the maintenance is reduced. Furthermore, by setting various judgment conditions for the process of determining the maintenance content so that cleaning is not performed more than necessary, it is possible to improve the efficiency of the maintenance. As described above, a printing device is realized that can reduce the workload of the operator related to the maintenance and perform the maintenance efficiently. Furthermore, the printing of the test pattern is performed in a state where the printing medium is transported at a constant speed. In other words, the printing of the test pattern is performed in a state close to the state where the main image (the image that should be printed) is printed. Therefore, the detection of the missing portion is performed with high accuracy. According to the first and second aspects of the present invention, for example, by performing cleaning when there is a large chipping and performing flushing when there is only a minor chipping, it is possible to suppress a decrease in printing efficiency while maintaining print quality. Furthermore, it is possible to effectively perform flushing so as to improve chipping. According to the third aspect of the present invention, for example, by performing cleaning when there is a large chipping and performing flushing when there is only a minor chipping, it is possible to suppress a decrease in printing efficiency while maintaining print quality. Furthermore, for example, after printing based on a certain job is completed, flushing of the printing unit can be reliably performed before printing based on the next job is started. In addition, the above-mentioned fourth and No. 5 above. According to the invention, when an event occurs that requires printing to be interrupted, necessary maintenance is reliably performed, thereby making it possible to maintain good print quality. Also The content of the maintenance is determined based on the inspection results of the test pattern printed immediately before. This makes it possible to perform maintenance so that any missing parts are reliably repaired. Furthermore, when an event occurs that requires printing to be interrupted, printing of the main image is stopped midway. This makes it possible to reduce the amount of wasted paper. Also, According to the sixth aspect of the present invention, when the print medium (typically roll paper) is changed, the necessary maintenance is performed reliably, thereby making it possible to maintain good print quality.

[0024] The above 7 According to the present invention, it is possible to prevent unnecessary maintenance from being performed, which allows the maintenance to be performed efficiently and, as a result, improves printing efficiency.

[0028] The above 8 According to the invention, cleaning of the printing section can be reliably performed while transport of the print medium is stopped.

[0031] According to the ninth aspect of the present invention, ~No. 4 above The same effects as those of the above invention can be obtained.

[0037] the above No. 11 to No. 14 above According to the invention, each, Above No. 1 ~No. 4 above The same effects as those of the above invention can be obtained. [Brief description of the drawings]

[0038] [Figure 1] 1 is an overall configuration diagram of a printing system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration example of an inkjet printing apparatus in the first embodiment. [Diagram 3] FIG. 2 is a plan view showing one configuration example of a printing unit in the first embodiment. [Figure 4] FIG. 2 is a block diagram showing a hardware configuration of a print control device in the first embodiment. [Diagram 5] FIG. 4 is a block diagram showing a schematic functional configuration of a control unit in the first embodiment. [Figure 6] FIG. 2 is a diagram for explaining the relationship between transport of print paper and maintenance in the first embodiment. [Figure 7] FIG. 2 is a block diagram showing a functional configuration related to control of maintenance in the first embodiment. [Figure 8] 5 is a flowchart showing a schematic procedure of a process relating to control of maintenance in the first embodiment. [Figure 9] 13 is a flowchart showing a detailed procedure of a maintenance content determination process in the first embodiment. [Figure 10] FIG. 11 is a block diagram showing a functional configuration related to maintenance control in a second embodiment of the present invention. [Figure 11] 13 is a flowchart showing a procedure of a process relating to control of maintenance in the second embodiment. [Figure 12] FIG. 13 is a diagram for explaining processing when printing is interrupted in the second embodiment. [Figure 13] FIG. 13 is a diagram for explaining processing when printing is interrupted in the second embodiment. [Figure 14] FIG. 13 is a block diagram showing a functional configuration related to maintenance control in a modification of the second embodiment. [Figure 15] 13 is a flowchart showing a procedure of a process relating to control of maintenance in a modification of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0040] <1. First embodiment> <1.1 Overall configuration of the 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 device 10 and a print data generating device 40. The inkjet printing device 10 and the print data generating device 40 are connected to each other by a communication line 5. The print data generating device 40 generates print data by performing RIP processing or the like on input data such as a PDF file. The print data generated by the print data generating device 40 is transmitted to the inkjet printing device 10 via the communication line 5. The inkjet printing device 10 outputs a print image on a printing paper as a print medium based on the print data transmitted from the print data generating device 40 without using a printing plate. The inkjet printing device 10 is composed of a printing machine main body 200, a print control device 100 that controls the operation of the printing machine main body 200, and an image inspection device 300 that inspects the print state. That is, this inkjet printing device 10 is a printing device with an inspection function. Some components of the image inspection device 300 are built into the printing machine main body 200.

[0041] 1, the image inspection device 300 is one component of the inkjet printing device 10 (i.e., the image inspection device 300 is included in the inkjet printing device 10), but this is not limiting. The image inspection device 300 may be a device independent of the inkjet printing device 10.

[0042] <1.2 Configuration of inkjet printing device> 2 is a schematic diagram showing an example of the configuration of the inkjet printing apparatus 10. As described above, the inkjet printing apparatus 10 is made up of the print control device 100, the printing press main body 200, and the image inspection device 300.

[0043] The printer body 200 includes a paper delivery section 21 that supplies print paper (e.g., roll paper) PA, a printing mechanism 20 that prints on the print paper PA, and a paper take-up section 28 that takes up the print paper PA after printing. The printing mechanism 20 includes a first drive roller 22 for transporting the print paper PA to the inside, a plurality of support rollers 23 for transporting the print paper PA inside the printing mechanism 20, a printing section 24 that ejects ink onto the print paper PA to perform printing, a cleaning mechanism 25 that cleans the printing section 24 (e.g., sucking ink from the nozzles and wiping the nozzle faces, which will be described later), a drying section 26 that dries the print paper PA after printing, an imaging section 310 that captures the print image (print paper PA after printing), and a second drive roller 27 that outputs the print paper PA from inside the printing mechanism 20. The imaging section 310 is a component of the image inspection device 300, and is configured using an image sensor such as a CCD or CMOS.

[0044] The print control device 100 controls the operation of the printing press main body 200 configured as described above. When a print output instruction command is given to the print control device 100, the print control device 100 controls the operation of the printing press main body 200 so that the print paper PA is transported from the paper delivery unit 21 to the paper winding unit 28. Then, first, the printing unit 24 prints on the print paper PA, then the drying unit 26 dries the print paper PA, and finally the imaging unit 310 captures an image of the print image. In addition, the cleaning mechanism 25 cleans the printing unit 24 as necessary.

[0045] The image inspection device 300 is composed of an imaging unit 310 and an image inspection computer 320. The captured image data Di obtained by capturing an image of a print image by the imaging unit 310 is sent to the image inspection computer 320. The image inspection computer 320 performs an inspection to detect chipping (defects) by image analysis of the captured image data Di. Note that the method is not limited to this, and an inspection to detect chipping (defects) may be performed by comparing and matching the captured image data Di with the print data Dp transmitted from the print data generating device 40, or by comparing and matching 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.

[0046] FIG. 3 is a plan view showing an example of the configuration of the printing unit 24. As shown in FIG. 3, the printing unit 24 is composed of inkjet head rows 240C, 240M, 240Y, and 240K of C (cyan), M (magenta), Y (yellow), and K (black) arranged in a conveying direction of the print paper PA. Each inkjet head row is composed of a plurality of inkjet heads (printing heads) 241 arranged in a staggered pattern. Each inkjet head 241 includes a large number of nozzles that eject ink. Each nozzle of the inkjet head 241 included in the C inkjet head row 240C ejects C ink, each nozzle of the inkjet head 241 included in the M inkjet head row 240M ejects M ink, each nozzle of the inkjet head 241 included in the Y inkjet head row 240Y ejects Y ink, and each nozzle of the inkjet head 241 included in the K inkjet head row 240K ejects K ink.

[0047] Although the configuration of the inkjet printing device 10 that performs color printing has been exemplified here, the present invention can also be applied when an inkjet printing device that performs monochrome printing is used. Also, although the configuration of the inkjet printing device 10 that uses water-based ink has been exemplified here, the present invention can also be applied when an inkjet printing device that uses UV ink (ultraviolet-curable ink), such as an inkjet printing device for label printing, is used. As described above, there is no particular limitation on the type of printing device as long as it is equipped with a printing unit that requires cleaning.

[0048] <1.3 Hardware configuration of print control device> FIG. 4 is a block diagram showing a hardware configuration of the print control device 100. As shown in FIG. 4, the print control device 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 control unit 115 is connected to a display unit (display device) 123. A keyboard 124 and a mouse 125 are connected to the input interface unit 116. The printer 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 serving as a computer-readable recording medium such as a CD-ROM or 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 by the operator to input instructions to this print control device 100.

[0049] The auxiliary storage device 121 stores a print control program (program for controlling the execution of print processing by the printer body 200). The CPU 111 reads the print control program P stored in the auxiliary storage device 121 into the memory 112 and executes it to realize various functions of the print 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 print control program P stored in the auxiliary storage device 121. The print control program P is stored in the computer-readable recording medium (non-transient recording medium) and provided. That is, for example, the user purchases an optical disk 6 as a recording medium for the print control program P, inserts it into the optical disk drive 122, reads out the print control program P from the optical disk 6, and installs it in the auxiliary storage device 121. Alternatively, the print 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.

[0050] <1.4 Control section> 5 is a block diagram showing a schematic functional configuration of a control unit 150 that is realized by executing a print control program P in the print control device 100. The control unit 150 generally includes a maintenance content determination unit 151, a transport control unit 152, a print control unit 153, a drying control unit 154, and an inspection control unit 155.

[0051] The maintenance content determination unit 151 determines the content of maintenance for the printing unit 24 (more specifically, the inkjet head 241) based on the results of the inspection by the image inspection device 300 (the inspection results Dr obtained by the image inspection computer 320).

[0052] The transport control unit 152 controls the speed (transport speed) at which the transport mechanism 210 transports the print paper PA. In this embodiment, the transport mechanism 210 is realized by the paper delivery unit 21, the first drive roller 22, the multiple support rollers 23, the second drive roller 27, and the paper winding unit 28 (see FIG. 2).

[0053] The print control unit 153 controls the ejection of ink from each nozzle included in each inkjet head 241 constituting the print unit 24. For example, the timing of ejecting ink and the amount of ink ejected are controlled. The print control unit 153 also controls the operation of the cleaning mechanism 25. When maintenance is performed on the print unit 24, the print control unit 153 controls the operation of the print unit 24 and the cleaning mechanism 25 according to the content of the maintenance determined by the maintenance content determination unit 151.

[0054] The drying control unit 154 controls the temperature (drying temperature) when the drying unit 26 dries the print paper PA. The inspection control unit 155 controls the timing at which the imaging unit 310 captures the print image.

[0055] Incidentally, when each job is processed, the conveyance control unit 152 controls the operation of the conveyance mechanism 210 so that the conveyance of the stopped print paper PA is started first. The conveyance speed gradually increases, and when it reaches a preset standard speed (a speed suitable for printing), it is maintained constant at the standard speed. Normally, printing is performed on the print paper PA while the conveyance speed is maintained at the standard speed (i.e., while the print paper PA is conveyed at a constant speed). After printing is completed, the conveyance control unit 152 controls the operation of the conveyance mechanism 210 so that the conveyance speed gradually decreases. As a result, the conveyance of the print paper PA stops. During the period when printing is being performed on the print paper PA conveyed at the standard speed, a post-processing device (not shown) connected inline to the inkjet printing device 10 may notify the inkjet printing device 10 of a slow request signal to decrease the printing speed depending on the progress of post-processing. When the inkjet printing device 10 receives such a notification, the transport control unit 152 controls the operation of the transport mechanism 210 to decelerate the transport speed of the print paper PA from the standard speed to a predetermined low speed, and continues transporting the print paper PA while maintaining the low speed constant. Printing continues while the print paper PA is transported at this low speed. Then, when the slow request signal is released, the transport control unit 152 controls the operation of the transport mechanism 210 to accelerate the transport speed of the print paper PA from the low speed to the standard speed, and then transports the print paper PA while maintaining the transport speed constant at the standard speed, and printing continues on the print paper PA being transported while maintaining the standard speed. When printing is completed, the transport control unit 152 controls the operation of the transport mechanism 210 so that the transport speed gradually decreases from the standard speed. This stops the transport of the print paper PA. On the other hand, if the slow request signal is not released, the transport control unit 152 controls the operation of the transport mechanism 210 so as to maintain the transport speed at a constant low speed and continue transporting the print paper PA, and printing on the print paper PA transported at the constant low speed also continues. Then, when printing is completed, the transport control unit 152 controls the operation of the transport mechanism 210 so as to gradually reduce the transport speed from the constant low speed. This stops the transport of the print paper PA.

[0056] As described above, the conveying control unit 152 accelerates the printing paper PA until the conveying speed changes from 0 to the reference speed before printing based on each job begins, maintains the conveying speed at a constant speed at least throughout the period during which printing based on each job is being executed, and decelerates the printing paper PA until the conveying speed changes from the constant speed to 0 after printing based on each job is completed.

[0057] <1.5 Maintenance Control> In the inkjet printing apparatus 10 according to this embodiment, maintenance of the printing unit 24 (more specifically, the inkjet head 241) is performed based on the results of inspection by the image inspection device 300. In this regard, in this embodiment, after printing based on each job is completed, a process is performed to determine whether or not maintenance needs to be performed and the type of maintenance (hereinafter referred to as a "maintenance content determination process"). Then, the operation of the printing unit 24 and the cleaning mechanism 25 is controlled by the print control unit 153 according to the result of the maintenance content determination process, whereby the desired maintenance of the printing unit 24 is performed.

[0058] In the present embodiment, when printing based on each job is performed, a test pattern is added to the print data Dp of each job to check for missing parts (defects such as missing nozzles). More specifically, a test pattern is added to the beginning and end of the print data Dp of each job. The test pattern added to the beginning of the print data Dp and the test pattern added to the end of the print data Dp may be the same pattern or different patterns. In the following, the test pattern added to the beginning of the print data Dp is referred to as a "first test pattern," and the test pattern added to the end of the print data Dp is referred to as a "second test pattern." For convenience, an image based on the print data Dp sent from the print data generating device 40 (the image that should be printed) is referred to as a "main image."

[0059] The first test pattern, the main image, and the second test pattern are all printed when the print paper PA is transported at a constant speed. In more detail, in a normal case, after the transport speed of the print paper PA changes from 0 to the reference speed, the first test pattern, the main image, and the second test pattern are printed in order, and then the transport speed of the print paper PA changes from the reference speed to 0. Also, there may be cases where the inkjet printing device 10 receives the above-mentioned slow request signal when printing is being performed on the print paper PA transported at the reference speed, the transport speed of the print paper PA is decelerated from the reference speed to a predetermined low speed, and printing on the print paper PA is performed to the end while maintaining this low speed constant. Even in such a case, at least a part of the main image and the second test pattern are printed while the print paper PA is transported at a constant speed, although at a speed lower than the reference speed. Then, after the second test pattern is printed, the transport speed of the print paper PA changes from a low speed lower than the reference speed to 0.

[0060] The relationship between the transportation of print paper PA and maintenance will be described with reference to Fig. 6. Here, it is assumed that job J1 is processed in the period from time t1 to time t6, and job J2 is processed in the period from time t8 to time t13, and attention is focused on the maintenance content determination process that is performed after printing based on job J1 is completed.

[0061] After a print instruction for job J1 is issued at time t0, the conveying speed gradually increases from time t1, and reaches the above-mentioned reference speed at time t2. Thereafter, the first test pattern, the main image, and the second test pattern are printed during the period from time t3 to time t4. In detail, the first test pattern is printed during the period indicated by the arrow with reference number 71, the main image is printed during the period indicated by the arrow with reference number 72, and the second test pattern is printed during the period indicated by the arrow with reference number 73. In this way, the first test pattern, the main image, and the second test pattern are printed during the period in which the conveying speed is maintained at the reference speed.

[0062] After printing based on job J1 is completed, the transport speed gradually decreases from time t5, and transport of the print paper stops at time t6. In the period from time t4 to time t6, the second test pattern printed during the period indicated by the arrow with reference numeral 73 is inspected, and a maintenance content determination process is performed based on the results of the inspection. If a decision is made in the maintenance content determination process to perform cleaning, cleaning of the printing unit 24 is performed by the cleaning mechanism 25 immediately after time t6.

[0063] After a print instruction for job J2 is given at time t7, the transport speed gradually increases from time t8, and reaches the reference speed at time t9. If a decision is made to perform flushing in the maintenance content decision process performed after printing based on job J1 is completed, flushing is performed based on control of the printing unit 24 by the print control unit 153 during the period from time t8 to time t10.

[0064] Thereafter, the first test pattern, the main image, and the second test pattern are printed during the period from time t10 to time t11. In detail, the first test pattern is printed during the period indicated by the arrow with reference number 74, the main image is printed during the period indicated by the arrow with reference number 75, and the second test pattern is printed during the period indicated by the arrow with reference number 76. Then, after printing based on job J2 is completed, the transport speed gradually decreases from time t12, and transport of the print paper stops at time t13.

[0065] 7 is a block diagram showing a functional configuration related to the control of maintenance. In addition to the above-mentioned maintenance content determination unit 151, the control unit 150 is provided with an inspection result storage unit 156 and a cleaning history storage unit 157 as components necessary for executing the maintenance content determination process. In addition, the print control unit 153, the printing unit 24, the cleaning mechanism 25, the imaging unit 310, and the image inspection computer 320 are involved in the control of maintenance.

[0066] The inspection result holding unit 156 holds the inspection result Dr sent from the image inspection computer 320. In the maintenance content determination process, the missing information LI, which is the inspection result related to missing (defective) such as a missing nozzle, among the inspection results Dr sent from the image inspection computer 320, is used. The cleaning history holding unit 157 holds the cleaning information CI sent from the maintenance content determination unit 151. The cleaning information CI stored in the cleaning history holding unit 157 is referred to as a cleaning history CH by the maintenance content determination unit 151 during the maintenance content determination process. The maintenance content determination unit 151 performs the maintenance content determination process, which will be described in detail later, based on the missing information LI and the cleaning history CH. Then, the print control unit 153 controls the operation of the printing unit 24 and the cleaning mechanism 25 so that the maintenance determined in the maintenance content determination process is performed.

[0067] The outline of the process related to the maintenance control will be described with reference to Fig. 8. First, after printing based on the job to be processed is completed, the printing unit 24 prints a second test pattern on the print paper PA (step S100). As described above, the second test pattern is printed during the period in which the transport speed of the print paper PA is maintained at the reference speed.

[0068] Next, the image inspection device 300 inspects the printed image of the second inspection pattern (step S110). First, the imaging unit 310 captures the printed image obtained by printing in step S100 (printing the second inspection pattern on the printing paper PA). Next, the captured image data Di obtained by the imaging unit 310 is sent to the image inspection computer 320. Then, the image inspection computer 320 performs image analysis of the captured image data Di. In this manner, chipping (defects) are detected based on the printed image of the second inspection pattern.

[0069] After the print image of the second test pattern is inspected, a maintenance content determination process is performed (step S120). This determines the content of the maintenance to be performed before printing based on the next job is started. A detailed explanation of the maintenance content determination process will be given later. Typically, the process of step S110 is performed during a period in which the transport speed of the print paper PA is maintained at the reference speed, and the process of step S120 is performed while the transport speed of the print paper PA is decelerating.

[0070] After the maintenance content determination process is completed, the maintenance determined in the maintenance content determination process is performed (step S130). However, if the maintenance content determination process determines that maintenance is not necessary, the maintenance is not performed. If the maintenance content determination process determines that cleaning is to be performed, cleaning of the printing unit 24 is performed based on the control of the printing unit 24 and the cleaning mechanism 25 by the print control unit 153 during the period when the transport of the printing paper PA is stopped. If the maintenance content determination process determines that flushing is to be performed, flushing (e.g., line flushing) is performed based on the control of the printing unit 24 by the print control unit 153 during the period from when the transport of the printing paper PA is resumed until printing based on the next job is started.

[0071] In this embodiment, step S100 realizes a test pattern printing step, step S110 realizes an inspection step, step S120 realizes a maintenance content determination step, and step S130 realizes a maintenance step.

[0072] Next, the procedure of the maintenance content determination process (the process of step S120 in FIG. 8) will be described with reference to FIG. 9. This maintenance content determination process is performed by the maintenance content determination unit 151. As described above, in this embodiment, the maintenance content determination process is performed after printing based on each job is completed. Note that the procedure described below is an example, and is not limited to this.

[0073] After the maintenance content determination process starts, first, it is determined whether or not maintenance of the printing unit 24 is necessary based on the inspection result of the second inspection pattern printed immediately before (step S121). For example, the number of chips indicated by the inspection result of the second inspection pattern printed immediately before is compared with a predetermined threshold, and if the number of chips is equal to or greater than the threshold, it is determined that maintenance is necessary, and if the number of chips is less than the threshold, it is determined that maintenance is not necessary. Also, for example, the size (area) of the maximum chipping indicated by the inspection result of the second inspection pattern printed immediately before is compared with a predetermined threshold, and if the size of the maximum chipping is equal to or greater than the threshold, it is determined that maintenance is necessary, and if the size of the maximum chipping is less than the threshold, it is determined that maintenance is not necessary.

[0074] If it is determined in step S121 that maintenance is not required, this maintenance content determination process ends. In this case, printing based on the next job begins without performing maintenance on the printing unit 24. If it is determined in step S121 that maintenance is required, the process proceeds to step S122.

[0075] In step S122, it is determined whether or not cleaning of the printing unit 24 is necessary based on the inspection results of the second test pattern printed immediately before. This determination is also made, for example, based on the results of comparing the number of chippings or the maximum chipping size indicated by the inspection results of the second test pattern printed immediately before with a predetermined threshold. In this regard, if a configuration is adopted in which the determinations in steps S121 and S122 are made based on the results of comparing the number of chippings with a threshold, the threshold used in step S122 is set to a value larger than the threshold used in step S121.

[0076] If it is determined in step S122 that cleaning is necessary, it is decided to perform cleaning, and the process proceeds to step S123. On the other hand, if it is determined in step S122 that cleaning is not necessary, it is decided to perform flushing, and the process proceeds to step S124.

[0077] In step S123, the strength (cleaning strength) when cleaning the printing unit 24 is determined. This determination is made based on the inspection result of the second test pattern printed immediately before and the inspection result of the second test pattern printed in the past. For example, if chipping has been detected in the same inkjet head a predetermined number of times or more, the cleaning strength of this time is set to a strength higher than the cleaning strength when the previous cleaning was performed, and if not, the cleaning strength of this time is set to the same strength as the cleaning strength when the previous cleaning was performed. The cleaning strength when the previous cleaning was performed can be grasped by referring to the above-mentioned cleaning history CH. Regarding lowering the increased cleaning strength, for example, a rule can be considered that when it is found that chipping has been improved after cleaning at the maximum strength is performed, the cleaning strength at the next cleaning is reduced to the normal strength.

[0078] When the process of step S123 is completed, this maintenance content determination process is completed. In this case, cleaning is performed with the cleaning strength set in step S123 during the period when the transport of the print paper PA is stopped when the printing target is shifted from the previous job to the next job.

[0079] In step S124, it is determined whether or not it is possible to increase the number of flushing sheets when flushing is performed. Regarding this, if a setting is made to use flushing sheets, it is determined that the number of flushing sheets can be increased, and if a setting is not made to use flushing sheets, it is determined that the number of flushing sheets cannot be increased. Note that a flushing sheet is a sheet on which a special pattern (hereinafter referred to as a "chipped improvement pattern") for improving (eliminating) chipping is printed. Therefore, the above "using a flushing sheet" means "printing a chipped improvement pattern." If it is determined in step S124 that the number of flushing sheets can be increased, the process proceeds to step S125. On the other hand, if it is determined in step S124 that the number of flushing sheets cannot be increased, the process proceeds to step S126.

[0080] In step S125, the number of flushing sheets in the current flushing is set to a number larger than the number of flushing sheets in the previous flushing. At this time, the difference between the number of flushing sheets in the current flushing and the number of flushing sheets in the previous flushing is determined, for example, based on the inspection result of the second test pattern printed immediately before. If a missing portion is detected in the same inkjet head a predetermined number of times or more consecutively based on the inspection result of the second test pattern printed immediately before and the inspection result of the second test pattern printed in the past, the number of flushing sheets in the current flushing may be set to a larger number. When the process of step S125 ends, this maintenance content determination process ends. In this case, during the period in which the conveying speed of the printing paper PA is accelerated to start printing based on the next job, printing of a missing portion improvement pattern (flushing for printing a missing portion improvement pattern) is performed according to the number set in step S125.

[0081] In step S126, the flushing amount in the current flushing is set to a larger amount than the flushing amount in the previous flushing. At this time, the difference between the flushing amount in the current flushing and the flushing amount in the previous flushing is determined, for example, based on the inspection result of the second test pattern printed immediately before. If a missing portion is detected in the same inkjet head a predetermined number of times or more consecutively based on the inspection result of the second test pattern printed immediately before and the inspection result of the second test pattern printed in the past, the flushing amount in the current flushing may be set to a larger amount. When the process of step S126 is completed, this maintenance content determination process is completed. In this case, during the period in which the conveying speed of the print paper PA is accelerated to start printing based on the next job, line flushing is performed with the flushing amount set in step S126. Of course, line flushing can be performed after the transport speed of the printing paper PA for starting printing based on the next job has reached the standard speed, but by performing line flushing during the acceleration period before the standard speed suitable for the actual printing is reached, the period during which the transport speed of the printing paper PA is maintained at a constant speed suitable for printing can be efficiently used for the actual printing.

[0082] Incidentally, maintenance (cleaning and flushing) may be performed commonly for all inkjet heads 241, or may be performed only for the inkjet head 241 for which a chipping has been detected.

[0083] If a setting has been made to use flushing sheets, even if the maintenance content determination process determines that maintenance is not necessary, a minimum amount of flushing is performed according to the number of flushing sheets set by the user before printing based on the next job is executed. Also, if a setting has not been made to use flushing sheets, even if the maintenance content determination process determines that maintenance is not necessary, a minimum amount of line flushing is performed before printing based on the next job is executed.

[0084] <1.6 Effects> According to this embodiment, the maintenance content determination unit 151 determines whether or not maintenance is required for the printing unit 24, and the type of maintenance if maintenance is required. This allows the content of maintenance to be determined without the need for an operator to make a decision, thereby reducing the workload of the operator in relation to maintenance. Furthermore, by setting various judgment conditions in the maintenance content determination process so that cleaning is not performed more than necessary, it is possible to improve the efficiency of maintenance. As described above, according to this embodiment, an inkjet printing apparatus 10 is realized that reduces the workload of the operator in relation to maintenance and can perform maintenance efficiently.

[0085] Furthermore, according to this embodiment, the second test pattern used to detect missing parts is printed while the print paper PA is transported at a constant speed. In other words, the second test pattern is printed under conditions similar to those in which the main image is printed. This allows for accurate detection of missing parts.

[0086] <2. Second embodiment> <2.1 Overview and configuration> In the above first embodiment, it is assumed that printing based on each job is completed without any problems. However, it is desirable to have a configuration that can obtain the same effect as the above first embodiment even when printing is interrupted for some reason. Therefore, a printing system with such a configuration will be described below as a second embodiment of the present invention.

[0087] In this embodiment, when printing is interrupted due to the printer main body 200, a maintenance content determination process and the maintenance content determined thereby are executed, similar to when printing based on each job ends in the first embodiment. Here, an event in which the remaining amount of roll paper in the paper feed unit 21 (see FIG. 2) falls below a predetermined value is given as an example of an event that causes printing to be interrupted. The paper feed unit 21 realizes the print medium supply unit.

[0088] The overall configuration of the printing system, the configuration of the inkjet printing device 10, the configuration of the printing unit 24, the hardware configuration of the print control device 100, and the general functional configuration of the control unit 150 are similar to those of the first embodiment described above, so descriptions will be omitted (see Figures 1 to 5).

[0089] <2.2 Maintenance Control> FIG. 10 is a block diagram showing a functional configuration related to maintenance control. In this embodiment, the control unit 150 is provided with a roll remaining amount monitoring unit 158 ​​in addition to the components in the first embodiment (see FIG. 7). The roll remaining amount monitoring unit 158 ​​monitors whether the remaining amount of roll paper in the paper delivery unit 21 is below a predetermined value, for example, based on data SD obtained from a sensor provided inside the printing machine main body 200. When the roll remaining amount monitoring unit 158 ​​detects that the remaining amount of roll paper is below a predetermined value, it instructs the print control unit 153 to stop printing and instructs the maintenance content determination unit 151 to execute a maintenance content determination process. In this embodiment, the roll remaining amount monitoring unit 158 ​​realizes a monitoring unit for detecting an event that requires printing to be interrupted.

[0090] The procedure of the process related to the control of the maintenance in this embodiment will be described with reference to Fig. 11. Note that the procedure described here is an example, and the present invention is not limited to this.

[0091] While printing is being performed, a determination is repeatedly made as to whether an event has occurred that requires printing to be interrupted (step S200). In this embodiment, specifically, the roll remaining amount monitoring unit 158 ​​determines whether the remaining amount of roll paper is below a predetermined value. If the remaining amount of roll paper is not below the predetermined value, there is no need to interrupt printing, and processing returns to step S200. If the remaining amount of roll paper is below the predetermined value, printing must be interrupted, and processing proceeds to step S210.

[0092] In step S210, the printing of the main image is stopped, and the above-mentioned second test pattern is printed. This will be described with reference to FIG. 12 and FIG. 13. In this embodiment, when an event occurs that requires printing to be interrupted, the print control unit 153 controls the operation of the printing unit 24 so that printing based on the job to be processed is stopped, and the second test pattern is printed next to the sheet being printed. For example, it is assumed that a print result as shown in FIG. 12 is obtained when printing is normally completed. In FIG. 12, the symbol C(S) represents the first test pattern, 1-20 represent the 1st to 20th sheets of the main image, and the symbol C(E) represents the second test pattern. Here, for example, when an event occurs that requires printing to be interrupted during printing of the 13th sheet of the main image (specifically, when it is detected that the remaining amount of roll paper has fallen below a predetermined value during printing of the 13th sheet of the main image), the printing of the 14th to 20th sheets of the main image is not performed, and the second test pattern is printed next to the 13th sheet of the main image as shown in FIG. 13. Then, under the control of the transport mechanism 210 by the transport control unit 152, the transport speed of the print paper PA gradually decreases.

[0093] After printing of the second test pattern is completed, the printed image of the second test pattern is inspected (step S220) by the image inspection device 300. In this step S220, similar to step S110 (see FIG. 8) in the first embodiment, chipping (defects) are detected based on the printed image of the second test pattern.

[0094] Thereafter, a maintenance content determination process is performed (step S230). The procedure of the maintenance content determination process is the same as that of the first embodiment (see FIG. 9). That is, based on the inspection result of the second test pattern printed immediately before, it is determined whether or not maintenance of the printing unit 24 is necessary. Then, if it is determined that maintenance of the printing unit 24 is necessary, it is determined whether or not cleaning of the printing unit 24 is necessary based on the inspection result of the second test pattern printed immediately before.

[0095] In the above example, printing was interrupted during printing of the 13th sheet of the original image. In this case, printing of the original image on a new roll of paper for that job can be restarted from the first sheet, or from the 14th sheet.

[0096] <2.3 Effects> According to this embodiment, when printing is interrupted due to the printing press main body 200, in the same manner as in the first embodiment described above, it is determined whether or not maintenance should be performed on the printing unit 24, and if maintenance is required, the type of maintenance. Therefore, similar to the first embodiment described above, this embodiment also realizes an inkjet printing apparatus 10 that reduces the workload of the operator in relation to maintenance and can efficiently perform maintenance.

[0097] Incidentally, in recent years, inkjet printing devices 10 have been developed that have a function (for example, called "auto splice") that automatically switches a roll of paper that is running low in the paper feed section 21 to a new roll of paper without human intervention. When the configuration of this embodiment is applied to an inkjet printing device 10 with such a function, necessary maintenance is reliably performed when switching rolls of paper. Specifically, cleaning and flushing of the printing section 24 are performed automatically while preparing to print on a new roll of paper. This makes it possible to maintain good print quality.

[0098] <2.4 Modifications> In the second embodiment described above, the maintenance content determination process was performed when printing was interrupted due to the printer main body 200. However, printing may be interrupted due to factors other than the printer main body 200. Therefore, a case in which printing is interrupted based on the inspection result of the first test pattern added to the beginning of the print data Dp will be described below as a modified example of the second embodiment described above.

[0099] FIG. 14 is a block diagram showing a functional configuration related to the control of maintenance in this modified example. In this modified example, the control unit 150 is provided with a chipping monitor 159 instead of the roll remaining amount monitor 158 (see FIG. 10) in the second embodiment. The chipping monitor 159 monitors whether or not the inspection result of the first inspection pattern corresponds to the chipping condition set by the user, by referring to the chipping information LI stored in the inspection result storage unit 156. When the chipping monitor 159 detects that the inspection result of the first inspection pattern corresponds to the chipping condition, it instructs the print control unit 153 to stop printing and instructs the maintenance content determination unit 151 to execute the maintenance content determination process. In this embodiment, the chipping monitor 159 realizes a monitoring unit for detecting an event that requires printing to be interrupted. Note that the contents of the maintenance content determination process are significantly different from those in the first embodiment and the second embodiment. This will be described later.

[0100] Here, the missing condition will be explained. The missing condition can be registered by the user in the print control device 100 before executing a job. Specific examples of missing conditions include the following conditions, where N and M are natural numbers: Chipping conditions: There are N or more consecutive chips in the inkjet head, or there are M or more chips in total in the inkjet head.

[0101] The procedure of the process related to the control of the maintenance in this modified example will be described with reference to Fig. 15. Note that the procedure described here is an example, and the present invention is not limited to this.

[0102] While printing is being performed, a determination is repeatedly made as to whether or not the inspection results meet the set conditions (step S300). In this modified example, specifically, the missing portion monitoring unit 159 determines whether or not the inspection results for the first inspection pattern meet the missing portion conditions set by the user. If the inspection results do not meet the missing portion conditions, there is no need to interrupt printing, and the process returns to step S300. If the inspection results meet the missing portion conditions, there is a need to interrupt printing, and the process proceeds to step S310.

[0103] In step S310, similar to step S210 (see FIG. 11) in the second embodiment, printing of the main image is stopped and printing of the second test pattern is performed. In step S320, similar to step S220 (see FIG. 11) in the second embodiment, the image inspection device 300 inspects the printed image for the second test pattern.

[0104] Thereafter, the cleaning history CH is referenced to determine whether or not cleaning has been performed a preset number of times for the inkjet head that meets the missing condition (step S330). If it is determined in step S330 that cleaning has been performed a preset number of times, the process proceeds to step S340. On the other hand, if it is determined in step S330 that cleaning has not been performed a preset number of times, the process proceeds to step S342.

[0105] In step S340, the cleaning strength of the current cleaning is set to a strength higher than the cleaning strength when the previous cleaning was performed. In step S342, the cleaning strength of the current cleaning is set to the same strength as the cleaning strength when the previous cleaning was performed. The cleaning strength when the previous cleaning was performed can be known by referring to the cleaning history CH described above. In steps S340 and S342, the cleaning strength may be adjusted based on information about the inkjet head determined to meet the missing condition in step S300 and the inspection result of the second inspection pattern. For example, when the inspection result of the second inspection pattern also indicates that there is a missing portion for the inkjet head determined to meet the missing condition in step S300, the cleaning strength of the inkjet head may be increased.

[0106] In this modification, the processes of steps S330, S340, and S342 correspond to the maintenance content determination process. That is, in the maintenance content determination process in this modification, only the strength of cleaning is determined based on the cleaning history CH, and the type of maintenance is not determined. In this modification, when printing is interrupted, cleaning of the printing unit 24 is performed instead of flushing the printing unit 24, regardless of the test result of the first test pattern.

[0107] <3.Other> The present invention is not limited to the above-described embodiments (including modified examples), and can be modified in various ways without departing from the spirit of the present invention. For example, in the above-described embodiments (including modified examples), neither cleaning nor flushing is performed between the processing of a preceding job and the processing of a subsequent job, but there may be cases in which both cleaning and flushing are performed between the processing of a preceding job and the processing of a subsequent job.

[0108] In the second embodiment and the modified example, the second test pattern is printed after the printing of the main image is interrupted and stopped, and the second test pattern is inspected, and the maintenance content is determined based on the inspection result. However, depending on the circumstances of the occurrence of the cause of the interruption or stop of the printing of the main image, the second test pattern may not be printed when the printing is interrupted or stopped. In addition, depending on the way the printing program of the printing device is written, there are cases where the progress of the job is progressed while printing the test pattern during the execution of the job. Therefore, when the second test pattern cannot be printed when the printing of the main image is interrupted or stopped, the maintenance content of the present invention may be determined based on the inspection result of the first test pattern printed on the printing medium PA before the printing of the main image. In addition, when the job progresses while printing the test pattern during the execution of the job, the maintenance content of the present invention may be determined based on the inspection result of the test pattern printed closest to the interruption or stop of the printing of the main image. In this way, even if the second test pattern cannot be printed when the printing of the main image is interrupted or stopped, the optimal maintenance can be appropriately performed. [Explanation of symbols]

[0109] 10...Inkjet printing device 24…Printing Department 25…Cleaning mechanism 100...Print control device 150...Control unit 151…Maintenance Content Decision Division 152...Transport control unit 153...Print control unit 156...Test result storage unit 157…Cleaning history storage unit 158...Roll remaining amount monitoring unit 159…Crack Monitoring Department 200…Printing machine body 210...Transport mechanism 300...Image inspection device 310…imaging unit 320...Image inspection computer

Claims

1. a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, and when chipping is detected consecutively a predetermined number of times for the same print head based on the inspection results obtained by the inspection device, the maintenance content determination unit includes, in the maintenance content for the printing unit, a content to increase the flushing amount when flushing is performed compared to the flushing amount when flushing was performed previously.

2. a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, and when chipping is detected a predetermined number of times consecutively for the same print head based on the inspection results obtained by the inspection device, the maintenance content determination unit includes, in the maintenance content for the printing unit, a content of using a larger number of flushing sheets when performing flushing than the number of flushing sheets used when the previous flushing was performed.

3. a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined by the maintenance content determination unit is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined by the maintenance content determination unit is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A printing device characterized in that, when the maintenance content determined by the maintenance content determination unit is flushing, the printing control unit controls the operation of the printing unit so that flushing of the printing unit is performed during the period when the transport control unit is accelerating the printing medium.

4. a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; a monitoring unit for detecting an event that requires printing to be interrupted; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the print control unit controls an operation of the print unit so that a second test pattern is printed as the test pattern during a period in which the transport speed is maintained at the constant speed; the second test pattern is printed after a main image based on a job to be processed is printed; the print control unit controls the operation of the print unit so that, when the monitoring unit detects an event that requires printing to be interrupted, the second test pattern is printed next to the sheet being printed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; a maintenance content determination unit that determines the content of maintenance to be performed on the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the second test pattern after the monitoring unit detects an event that requires printing to be interrupted.

5. the print control unit controls an operation of the print unit so that a first test pattern is printed as the test pattern during a period in which the transport speed is maintained at the constant speed; 5. The printing apparatus according to claim 4, wherein the first test pattern is printed before printing of a main image based on the job to be processed is performed.

6. A transport mechanism for transporting a print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit; a monitoring unit for detecting an event that requires printing to be interrupted; a printing medium supply unit for supplying the printing medium to the printing unit; Equipped with the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of the maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern, the print control unit controls the operation of the print unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit; the maintenance content determination unit determines the content of maintenance to be performed on the printing unit after the monitoring unit detects an event that requires printing to be interrupted; The printing device, wherein the monitoring section detects an event in which the amount of printing media remaining in the printing media supply section falls below a predetermined value as an event in which printing should be interrupted.

7. 7. The printing device according to claim 1, wherein the maintenance content determination unit further determines whether or not execution of maintenance on the printing unit is necessary.

8. A printing device as described in any one of claims 1 to 3 and 7, characterized in that when the maintenance content determined by the maintenance content determination unit is cleaning, the printing control unit controls the operation of the printing unit and the cleaning mechanism so that cleaning of the printing unit is performed during the period when the transport control unit maintains the transport speed at 0.

9. the print control unit controls an operation of the printing unit so that a first test pattern and a second test pattern are printed as the test patterns during a period in which the transport speed is maintained at the constant speed; the first test pattern is printed before a main image based on a job to be processed is printed; A printing device as described in any one of claims 1 to 3, 7 and 8, characterized in that the second test pattern is printed either after the main image based on the job to be processed has been printed, after the printing of the main image has been interrupted, or after the printing of the main image has been stopped.

10. a transport mechanism for transporting the print medium; a printing unit including a plurality of print heads that print on the print medium by ejecting ink; a cleaning mechanism for cleaning the printing unit; An inspection device that inspects a printed image obtained by printing; a transport control unit that controls a transport speed at which the transport mechanism transports the print medium; a print control unit that controls operations of the printing unit and the cleaning mechanism; a maintenance content determination unit that determines the content of maintenance for the printing unit and transmits cleaning information; a cleaning history storage unit that stores the cleaning information transmitted from the maintenance content determination unit as a cleaning history; Equipped with The cleaning strength at the time when the cleaning mechanism performed the previous cleaning can be known by referring to the cleaning history, the transport control unit accelerates the print medium until the transport speed changes from 0 to a predetermined reference speed before printing based on each job starts, transports the print medium so that the transport speed of the print medium includes a period during which the transport speed of the print medium is maintained at a constant speed including the reference speed at least during a period during which printing based on each job is being executed, and decelerates the print medium until the transport speed changes from the constant speed to 0 after printing based on each job ends; the print control unit controls an operation of the print unit so that a test pattern is printed on the print medium during a period in which the transport speed is maintained at the constant speed; the maintenance content determination unit determines the content of maintenance for the printing unit based on an inspection result obtained by the inspection device inspecting a printed image of the inspection pattern and the cleaning history; the content of the maintenance determined by the maintenance content determination unit includes a cleaning strength when the cleaning mechanism cleans the printing unit; A printing device, characterized in that the print control unit controls operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined by the maintenance content determination unit.

11. A maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, and a print control unit that controls the operation of the printing unit and the cleaning mechanism, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that, when the maintenance content determined in the maintenance content determination step is flushing, and when chipping is detected a predetermined number of times consecutively for the same print head based on the inspection results obtained in the inspection step, the maintenance content for the printing unit in the maintenance content determination step includes a content that the amount of flushing when flushing is performed is greater than the amount of flushing when flushing was performed previously.

12. A maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, and a print control unit that controls the operation of the printing unit and the cleaning mechanism, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step for determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that, when the maintenance content determined in the maintenance content determination step is flushing, and when a predetermined number of consecutive defects are detected for the same print head based on the inspection results obtained in the inspection step, the maintenance content for the printing unit in the maintenance content determination step includes a content of increasing the number of flushing sheets when performing flushing compared to the number of flushing sheets used when the previous flushing was performed.

13. A maintenance method for a printing device including a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, a print control unit that controls the operation of the printing unit and the cleaning mechanism, a transport mechanism that transports the printing medium, and a transport control unit that controls a transport speed at which the transport mechanism transports the printing medium, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The maintenance for the printing unit includes cleaning and flushing. If the maintenance content determined in the maintenance content determination step is cleaning, the print control unit controls the operation of the print unit and the cleaning mechanism so that cleaning of the print unit is performed, and if the maintenance content determined in the maintenance content determination step is flushing, the print control unit controls the operation of the print unit so that flushing of the print unit is performed; A maintenance method for a printing device, characterized in that when the maintenance content determined in the maintenance content determination step is flushing, the printing control unit controls the operation of the printing unit so that flushing of the printing unit is performed during the period when the transport control unit is accelerating the printing medium.

14. A maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, a cleaning mechanism that cleans the printing unit, a print control unit that controls the operation of the printing unit, and a monitoring unit that detects an event that requires printing to be interrupted, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit based on an inspection result obtained by inspecting the print image in the inspection step after an event that requires printing to be interrupted is detected by the monitoring unit; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, the print control unit controls an operation of the printing unit so that a second test pattern is printed as the test pattern during a period in which the print medium is transported at the constant speed in the test pattern printing step; the second test pattern is printed after a main image based on a job to be processed is printed; the print control unit controls the operation of the print unit so that, when the monitoring unit detects an event that requires printing to be interrupted, the second test pattern is printed next to the sheet being printed; A maintenance method for a printing device, characterized in that in the maintenance content determination step, the content of maintenance for the printing unit is determined based on the inspection results obtained by inspecting the printed image of the second test pattern in the inspection step.

15. A maintenance method for a printing device having a printing unit consisting of a plurality of print heads that print on a printing medium by ejecting ink, and a cleaning mechanism that cleans the printing unit, comprising: a test pattern printing step in which the printing unit prints a test pattern on the printing medium while the printing medium is being transported at a constant speed; an inspection step of inspecting a printed image obtained by printing the test pattern; a maintenance content determination step of determining the content of maintenance for the printing unit and accumulating cleaning information as a cleaning history; a maintenance step of controlling operations of the printing unit and the cleaning mechanism in accordance with the maintenance content determined in the maintenance content determination step; Including, The cleaning strength at the time when the cleaning mechanism performed the previous cleaning can be known by referring to the cleaning history, In the maintenance content determination step, a maintenance content for the printing unit is determined based on an inspection result obtained by inspecting the printed image in the inspection step and the cleaning history, A maintenance method for a printing device, wherein the content of the maintenance determined in the maintenance content determination step includes a cleaning strength when the cleaning mechanism cleans the printing section.

Images