JP7822252B2 - Print control device, print control method, and print control program - Google Patents

Description

The present invention relates to a printing control device, etc.

Inkjet printing devices such as those described in Patent Document 1 are known as printing devices that print on sheet-like substrates such as rolled paper. Print heads or printing nozzles for each color, such as cyan (C), magenta (M), yellow (Y), and black (K), eject ink of that color onto the substrate, which is transported by rotating transport rollers or the like, to print the desired image.

Japanese Patent Application Laid-Open No. 2004-181874

In this specification, the term "splicing" or "splicing" (when the substrate is paper, such as a roll of paper) refers to the process of splicing a "new" substrate (hereinafter referred to as the "second substrate") onto an "old" substrate (hereinafter referred to as the "first substrate") being printed by the print head, thereby switching between the old and new substrates with little or no interruption to the printing device. Because adhesives such as tape remain at the splice or splice location between the first and second substrates, it is preferable to temporarily retract the print head from the printing position to avoid contact with the adhesive. However, because the substrate continues to be transported while the print head is retracted, it is necessary to readjust the timing and position for the start of printing on the substrate (the spliced second substrate) after the print head returns to the printing position. The substrate that continues to be transported during this time is not printed on by the print head and is wasted. If the substrate is paper, this results in a large amount of wasted paper.

The present invention was made in light of these circumstances, and aims to provide a print control device and the like that can reduce the waste of printed material that occurs when the print head is retracted from the transfer position.

To solve the above problem, one aspect of the present invention is a print control device that controls a printing device equipped with a print head that ejects ink onto a transported substrate, and includes an insertion detection unit that detects, upstream of the print head in the transport direction, that a new second substrate has been inserted onto a first substrate being printed by the print head, and a print head retraction unit that retracts the print head from the first substrate and the second substrate when the insertion position where the second substrate has been inserted passes the point being printed by the print head, while the print head is being transported a distance that is an integer multiple of the unit print length by the print head.

In this configuration, the print head is retracted only while the joined first and second substrates are transported a distance that is an integral multiple of the unit print length, allowing the print head to begin printing the unit print length on the second substrate immediately after returning from retraction. This reduces the waste of substrate (waste paper, etc.) that occurs when the print head is retracted from the transition position.

Another aspect of the present invention is a printing control method. This method controls a printing device equipped with a print head that ejects ink onto a transported substrate, and includes an insertion detection step that detects, upstream in the print head transport direction, that a new second substrate has been inserted onto a first substrate being printed by the print head, and a print head retraction step that, when the insertion position where the second substrate has been inserted passes the location being printed by the print head, retracts the print head from the first substrate and the second substrate while the print head is transported a distance that is an integer multiple of the unit print length.

The present invention also encompasses any combination of the above components, as well as any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc.

This invention reduces the waste of printed material that occurs when the print head is retracted from the transfer position.

1 illustrates a schematic configuration of a printing device controlled by a print control device. FIG. 10 is a plan view of the printing medium, schematically illustrating the retraction of the print head by the print head retraction section.

The following describes in detail the form for carrying out the present invention (hereinafter also referred to as the embodiment) with reference to the drawings. In the description and/or drawings, the same or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant explanations are omitted. The scale and shape of each part shown in the drawings are set for convenience in order to simplify the explanation, and should not be interpreted as limiting unless otherwise specified. The embodiment is an example and does not limit the scope of the present invention in any way. All features and combinations thereof described in the embodiment are not necessarily essential to the present invention.

Figure 1 schematically illustrates the configuration of a printing device 10 controlled by a print control device 30 according to an embodiment of the present invention. The printing device 10 performs inkjet printing using a print head 11 on a sheet-like substrate 50 (50A and/or 50B), such as a roll of paper or a web. In the illustrated example, primary images P1 and P2 of a unit print length (hereinafter also referred to as the "repeat length") equivalent to the printing surface or paper surface of one page are pre-printed on a first substrate 50A wound around a first rotating shaft 41, which is the old shaft, and a second substrate 50B wound around a second rotating shaft 42, which is the new shaft. The unit print length is schematically represented by the distance between successive primary images P1 or successive primary images P2 in the transport direction (generally from left to right in Figure 1).

Under the control of the register control unit 20 and the ink ejection control unit 23, the print head 11, which constitutes the inkjet printing unit, performs secondary printing (hereinafter also referred to as "overprinting") of substantially the same repeat length on the substrates 50A and 50B on which the primary print of the primary patterns P1 and P2 of the repeat length has been performed. As shown in the schematic diagram, the secondary pattern P3 generated by the overprinting performed by the print head 11 is printed on top of the primary patterns P1 and P2. The register control unit 20, which will be described later, reduces the printing misalignment (hereinafter also referred to as "register error") between the primary patterns P1 and P2 and the secondary pattern P3. The position control of each subsequent print to reduce the register error is also referred to as "register control." While this embodiment describes an example in which the print head 11 performs overprinting (secondary printing) on the substrate 50 on which primary printing has already been performed, the present invention is equally applicable when the print head 11 performs normal printing rather than overprinting.

While any paint may be used in the primary printing applied to the substrate 50 in advance and in the secondary printing (overprinting) by the print head 11, in this embodiment, inks of various colors, such as cyan (C), magenta (M), yellow (Y), and black (K), are used in both the primary printing and the secondary printing. Note that in the print head 11 acting as the overprinting unit, a surface protective paint such as varnish for protecting the surface of the substrate 50 may be used as the overprinting paint.

The print head 11 includes one or more print heads or print nozzles that eject ink of one or more colors onto the substrate 50 being transported under the control of the ink ejection control unit 23. One print head 11 in FIG. 1 represents one or more of these print heads or print nozzles. When multiple print heads 11 are provided, each print head 11 typically ejects ink of a different color onto the substrate 50. The number of print heads 11 is arbitrary; for example, by providing four print heads 11, full-color printing can be performed on the substrate 50 using the four common colors of ink: cyan (C), magenta (M), yellow (Y), and black (K).

The transport roller 12 is a transport unit or rotary transport unit that transports the substrate 50 in the transport direction at a position opposite the print head 11 during inkjet printing, and is driven to rotate counterclockwise in Figure 1 by a roller drive motor 22. The size (specifically, radius and circumference) of the transport roller 12 is arbitrary, but for example, if the circumference of the transport roller 12 is N times the repeat length (N is a natural number), the print head 11 prints the secondary pattern P3 N times on the substrate 50 during one rotation of the transport roller 12.

The print head 11 itself and/or the printing location (ink ejection location) by the print head 11 may be movable in a direction intersecting the transport direction of the substrate 50 (a direction generally from left to right at the position facing the print head 11 in Figure 1). For example, the print head 11 and/or the printing location may be movable back and forth in a direction perpendicular to the transport direction of the substrate 50 (a direction perpendicular to the plane of the paper in Figure 1). In this case, the reciprocating movement speed or scanning speed of the print head 11 and/or the printing location is greater than the transport speed of the substrate 50 which intersects or is perpendicular to it.

Specifically, while the substrate 50 is transported by one pixel in the transport direction (hereinafter also referred to as the "vertical direction"), the print head 11 and/or printing location scans all pixels in the scanning direction (hereinafter also referred to as the "horizontal direction"), and ink is selectively ejected onto the pixel locations where printing is to be performed. To ensure proper inkjet printing, the scanning speed or printing speed of the print head 11 and/or printing location may be adaptively controlled in accordance with the transport speed of the substrate 50 or the rotation speed of the transport roller 12. Alternatively, the scanning speed of the print head 11 and/or printing location may be constant, with a stop or standby period between each horizontal scan that corresponds to the transport speed of the substrate 50 or the rotation speed of the transport roller 12. Furthermore, the scanning speed or stop period of the print head 11 and/or printing location may be constant regardless of the transport speed of the substrate 50 or the rotation speed of the transport roller 12. In the following, it is assumed that the transport speed of the printing substrate 50 or the rotation speed of the transport roller 12 is a constant production speed, and that the scanning speed and stop period of the print head 11 and/or printing location are also constant.

The print head 11 prints register marks for each repeat length for register control by the register control unit 20, which will be described later. Similar register marks are also printed for each repeat length in the primary printing that is performed in advance on the printing substrate 50. On each printing surface or page, the primary register marks from the primary printing and the secondary register marks from the secondary printing (print head 11) are printed at predetermined intervals along the transport direction of the printing substrate 50.

The register control unit 20 detects the printing misalignment (register error) between the primary patterns P1, P2 and the secondary pattern P3 as a deviation from the specified spacing between the primary and secondary register marks, and controls the phase (rotational position) of the transport roller 12 via the roller drive motor 22 to reduce this. Alternatively, the register control unit 20 may control the printing location, scanning speed, and stop period of the print head 11 to reduce the register error detected by the mark sensor 21. The register control unit 20 also controls the ink discharge control unit 23 to cause the print head 11 to discharge ink to sequentially print the desired secondary pattern P3 on the printing substrate 50, with ink discharge timing synchronized with the roller drive motor 22. The spacing between the primary and secondary register marks in the transport direction is detected by the mark sensor 21 located downstream of the transport roller 12. The mark sensor 21 has two detectors, such as photodetectors, that can simultaneously detect the primary and secondary register marks. The distance between these two detection units in the transport direction is approximately equal to the intended distance (predetermined distance) between the primary and secondary register marks, so while one detection unit detects the primary register mark, the other detection unit detects the secondary register mark. If the distance between the primary and secondary register marks detected by mark sensor 21 deviates from the predetermined distance, register control unit 20 issues a command to roller drive motor 22, print head 11, and/or head drive motor 35 to reduce the printing misalignment (register error).

As shown in FIG. 1A, when the remaining amount of the first substrate 50A being unwound in the transport direction from the first rotating shaft 41 (the old shaft) becomes low, the second substrate 50B being unwound in the transport direction from the second rotating shaft 42 (the new shaft) is spliced onto the first substrate 50A being printed by the print head 11. This switching between the old and new rolls of paper or other substrates 50A and 50B is called splicing or splicing. The first substrate 50A and the second substrate 50B are adhered to each other with an adhesive such as tape at the splicing position RC, which serves as the splicing position. Then, a cutting unit 43 such as a cutter provided before the splicing position RC in FIG. 1A cuts the first substrate 50A at the cutting position CP. As a result, except for the short sections immediately before and after the splice position RC where the first and second substrates 50A and 50B overlap, the printed material 50 is made up of only the first printed material 50A after the splice position RC (right side in Figure 1), and is made up of only the second printed material 50B before the splice position RC (left side in Figure 1).

As a result of the splicing process described above, adhesive materials such as tape remain at the splice position RC between the first substrate 50A and the second substrate 50B. Therefore, as shown in FIG. 1B, it is preferable to temporarily retract the print head 11 from the printing position (the position of the print head 11 in FIG. 1A) so as not to come into contact with the adhesive material. The print control device 30 according to this embodiment, described below, reduces waste of the substrate 50 caused by the retraction of the print head 11 from the splice position RC.

In addition to the aforementioned register control unit 20 and ink discharge control unit 23, the print control device 30 also includes an insertion/replacement detection unit 31, a cutting length detection unit 32, a transport amount detection unit 33, and a print head retraction unit 34. These functional blocks are realized through the cooperation of hardware resources such as the computer's central processing unit, memory, input devices, output devices, and peripheral devices connected to the computer, as well as software executed using these resources. Regardless of the type of computer or its installation location, each of the above functional blocks may be realized by the hardware resources of a single computer, or by combining hardware resources distributed across multiple computers.

The splice detection unit 31 detects that a new second substrate 50B has been spliced (spliced) onto the first substrate 50A being printed by the print head 11 at the splice position RC, upstream of the print head 11 in the transport direction. Specifically, the splice detection unit 31 may detect splicing based on a cut signal generated when the cutting unit 43 cuts the first substrate 50A at the cutting position CP, or may detect splicing based on an adhesion signal generated when the first substrate 50A and the second substrate 50B are bonded to each other at the splice position RC (or when the bonded portion of the first substrate 50A and the second substrate 50B passes the splice position RC). As will be described later with regard to the cut length detection unit 32, the distance in the feed direction between the splice position RC and the cut position CP (the length of the tail region TL, described later) is typically a known constant value, so whether splicing is detected based on a cut signal or an adhesive signal, both the splice position RC and the cut position CP at that time are detected by the splice detection unit 31.

The cut length detection unit 32 detects the cut length, which is the distance in the transport direction between the cutting position CP and the splice position RC of the first substrate 50A, which is cut after the second substrate 50B is spliced. Specifically, the cut length detection unit 32 may detect the cut length based on the splice position RC (the position of the adhesive material, etc.) when the cutting unit 43 cuts the first substrate 50A at the cutting position CP. Alternatively, the cut length detection unit 32 may store in advance the cut length between the cutting position CP and the splice position RC, which is typically a known set value. As schematically shown in FIG. 1B, in the tail region TL between the splice position RC and the cutting position CP in the substrate 50, the first substrate 50A and the second substrate 50B coexist over the cut length detected by the cut length detection unit 32.

Although not shown, just as the tail region TL is formed when the rear end of the first substrate 50A remains before the splice position RC (generally to the left in FIG. 1), a front region where the leading end of the second substrate 50B remains may be formed after the splice position RC (generally to the right in FIG. 1). As will be described later, the print control device 30 (particularly the print head retraction unit 34) according to this embodiment temporarily retracts the print head 11 from the printing position so that the print head 11 does not come into contact with not only the splice position RC where the adhesive remains, but also the tail region TL and/or the front region where the first substrate 50A and the second substrate 50B coexist.

The transport distance detection unit 33 detects the transport distance of the printing substrate 50 after splicing is detected by the splice detection unit 31 using one or more length measuring rolls 44 provided between the splice position RC and the print head 11 in FIG. 1A. This makes it possible to detect the approach of the splice position RC and the front and rear tail regions TL and/or front regions in FIG. 1A to the print head 11 as well as the specific distance from the print head 11, as shown in FIG. 1B.

As shown in FIG. 1B, the print head retraction unit 34 retracts the print head 11 from the substrate 50 when the splice position RC, the front and rear tail regions TL, and/or the front region pass through the printing area of the print head 11. In the example of FIG. 1B, the head drive motor 35, upon receiving a retraction command from the print head retraction unit 34, drives the print head 11 in a direction (downward in FIG. 1) away from the substrate 50 or the transport roller 12 to temporarily retract it. As will be described later with reference to FIG. 2, the print head 11 is retracted to the retracted position in FIG. 1B by the print head retraction unit 34 and the head drive motor 35 while the substrate 50 is transported a distance that is a predetermined integer multiple of the repeat length. Then, after the print head 11 begins to retract, when the transport amount of the printing substrate 50 detected by the transport amount detection unit 33 reaches a predetermined integer multiple of the repeat length, the print head 11 is driven by the print head retraction unit 34 and head drive motor 35 in a direction approaching the printing substrate 50 or transport roller 12 (upward in Figure 1) and returns to the printing position in Figure 1A.

Figure 2 is a plan view of the substrate 50, schematically illustrating the retraction of the print head 11 by the print head retraction section 34. The left-to-right direction in this figure is the transport direction of the substrate 50, and patterns P1 to P3 are repeatedly printed along this direction with a repeat length 1. As mentioned above, an adhesive such as tape remains at the splice position RC between the first substrate 50A and the second substrate 50B. Furthermore, a tail region TL is formed in the section preceding the splice position RC (left side in Figure 2) by the remaining rear end of the first substrate 50A. Meanwhile, in the example shown in this figure, a front region is not formed by the leading end of the second substrate 50B in the section following the splice position RC (right side in Figure 2). In other words, at the splice position RC, the leading end of the second substrate 50B is adhered to the first substrate 50A by an adhesive such as tape. Thus, in the example of Figure 2, only the first substrate 50A exists after the splice position RC, while the first substrate 50A and the second substrate 50B coexist in the tail region TL before the splice position RC, and only the second substrate 50B exists before the tail region TL.

The print head retraction unit 34 retracts the print head 11 from the substrate 50 when one or more pages (repeat length) including the splice position RC and the tail region TL (and/or the front region) pass the area printed by the print head 11. In the illustrated example, the print head 11 is retracted from the substrate 50 when a total of three pages pass the area printed by the print head 11: one page on the front side (right side) including the splice position RC (and the front region) and two pages on the tail side (left side) not including the splice position RC but including the tail region TL.

Specifically, the print head retraction unit 34 starts retracting the print head 11 at retraction start time ST, which is before the splice position RC passes the printing location and when the print head 11 completes printing the repeat length (page) immediately before the splice position RC. The distance between the print head 11 and the splice position RC at retraction start time ST is l/ _f as shown in the figure. In other words, the print head retraction unit 34 starts retracting the print head 11 when the splice position RC reaches a distance l/ _f just before the print head 11 (retraction start time ST). The retraction start time ST is detected, for example, by the transport distance detection unit 33. As described above, the transport distance detection unit 33 detects the transport distance of the printing material 50 after the splice detection unit 31 detects the splice. Here, if the distance in the transport direction between the splice position RC in FIG. 1A and the print head 11 when splicing is detected is D, and the transport amount of the splice position RC from the state of FIG. 1A detected by the transport amount detection unit 33 is d, the time when d = D - l _f is the start time ST of the evacuation.

As shown in FIG. 2, if a front area is not formed due to the excess leading edge of the second printing material 50B, the front-side waiting area, including the splice position RC, is kept to a minimum of one page. Here, if the length of the front-side waiting area is expressed as an integer "n" in units of the repeat length l, n is 1 or greater, and can be set to 1 if no front area is formed. Note that if a front area is formed, the print head waiting section 34 may begin waiting for the print head 11 at a waiting start time ST' earlier than the waiting start time ST in FIG. 2 to prevent the print head 11 from contacting the front area. For the waiting start time ST' shown, n = 2. Thus, if a front area is formed, n may be 2 or greater. However, as with the tail area TL described below, a minimum n can be set according to the length of the front area. By providing such a front-side waiting area (length n x l), contact between the splice position RC and the front area and the print head 11 can be prevented. Furthermore, the print head 11 can continue printing the repeat length on the first printing substrate 50A (printing the secondary pattern P3 on the primary pattern P1 that was previously printed as a primary print, as in the illustrated "P1 & P3") until just before the standby start time ST.

The print head retraction section 34 ends the retraction of the print head 11 at the retraction end time ED, which occurs after the splice position RC and the tail region TL (cut length) have passed the printing location and when the print head 11 begins printing the repeat length (page) immediately following the tail region TL. Here, when the length of the tail-side retraction section is expressed as an integer "m" in units of the repeat length l, m is 1 or greater. In the illustrated example, when a tail region TL longer than the repeat length l is formed, m can be 2 or greater (m = 2). The length of such a tail-side retraction section, "m × l," is typically longer than the length of the tail region TL (cut length). Furthermore, the total length of the retraction sections, including the tail and front sides, "(m + n) × l," is always longer than the total length of the tail region TL (and the front region). Providing such a tail-side retraction section (length m × l) prevents contact between the print head 11 and the splice position RC and tail region TL. Furthermore, immediately after returning from retraction at the end of retraction ED, the print head 11 can begin printing the repeat length on the second printing substrate 50B under the control of the ink discharge control unit 23 (printing the secondary pattern P3 on the primary pattern P2 that was previously printed as a primary print, as in the illustrated "P2 & P3").

The distance between the print head 11 and the splice position RC at the retraction end ED is _lt + m x l as shown in the figure (where _lt + _lf = l). In other words, the print head retraction unit 34 ends the retraction of the print head 11 when the splice position RC reaches the distance _lt + m x l ahead of the print head 11 (retraction end ED). The retraction end ED is detected, for example, by the transport distance detection unit 33, in the same manner as the retraction start ST described above. Specifically, the retraction end ED occurs when the transport distance d of the splice position RC from the state in Figure 1A detected by the transport distance detection unit 33 becomes D + _lt + m x l.

As described above, the retraction section of the print head 11 defined by the print head retraction section 34 can be set to a minimum length (m+n) x l to avoid contact between the print head 11 and the splice position RC, the front and rear tail regions TL, and/or the front region. By setting the length of the retraction section to an integer (m+n) times the repeat length l, the print head 11 can continue printing the repeat length on the first substrate 50A until just before the retraction start time ST, and can begin printing the repeat length on the second substrate 50B immediately after returning from retraction at the retraction end time ED. Therefore, this embodiment reduces waste of the substrate 50 (such as wasted paper) associated with the retraction of the print head 11 from the splice position RC, the front and rear tail regions TL, and/or the front region.

The length "n" of the front-side waiting area and the length "m" of the tail-side waiting area may be set independently. As mentioned above, the length "n" of the front-side waiting area is typically set to "1" when no front area is formed, and is set manually or automatically to the smallest natural number corresponding to the length of the front area when a front area is formed. Furthermore, the length "m" of the tail-side waiting area is set manually or automatically to the smallest natural number corresponding to the length of the tail area TL. Unlike the repeat length l, which varies depending on the print content, the tail area TL is often set to a fixed length (e.g., 50 cm). Therefore, the optimal "m" can be automatically derived based on the repeat length l set for each print and the given (fixed) cutting length.

The present invention has been described above based on an embodiment. Various modifications are possible to the combinations of the components and processes in the exemplary embodiment, and it will be obvious to those skilled in the art that such modifications are within the scope of the present invention.

In the embodiment, a web of rolled paper is used as the substrate 50, but the printing device 10 can print on any substrate. For example, the substrate can be a sheet made of any material, or the surface of a solid object of any shape, such as a container or product.

The configuration, action, and functionality of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources that can be used include processors, ROM, RAM, and various integrated circuits. Examples of software resources that can be used include operating systems, application programs, and other programs.

10 Printing device, 11 Print head, 12 Conveyor roller, 20 Register control unit, 30 Print control device, 31 Insertion detection unit, 32 Cut length detection unit, 33 Conveyance amount detection unit, 34 Print head retraction unit, 50A First printing material, 50B Second printing material.

Claims (5)

A print control device that controls a printing device having a print head that ejects ink onto a conveyed printing substrate,
an insertion detection unit that detects, at a front stage in the transport direction of the print head, that a new second substrate has been inserted onto a first substrate being printed by the print head, based on a cut signal indicating that the first substrate has been cut and/or an adhesion signal indicating that the first substrate and the second substrate have been adhered to each other;
a print head retraction unit that retracts the print head from the first and second substrates while the print head is transported a distance that is an integral multiple of a unit print length of repeated printing by the print head so that a cut piece of the first substrate and/or an adhesive piece of the first and second substrates do not come into contact with the print head when the joining position where the second substrate is joined passes through a printing position where ink is ejected by the print head;
Equipped with
The printing machine further includes a cutting length detection unit that detects a cutting length from the joining position of the first printing material that is cut after the second printing material is joined,
The print head retraction unit completes retraction of the print head after the joining position and the cutting length have passed the printing location . The print control device described in claim 1, wherein the print head retraction unit begins retracting the print head when printing of the unit print length is completed before the transition position passes the printing location. a primary printing of the unit printing length is applied to the first printing substrate and the second printing substrate;
the print head performs secondary printing of the unit printing length on the first printing substrate and the second printing substrate;
The print control device according to claim 1 or 2. A printing control method for controlling a printing device having a print head that ejects ink onto a conveyed printing substrate, comprising:
an insertion detection step of detecting that a new second substrate has been inserted onto a first substrate being printed by the print head at an upstream stage in the transport direction of the print head, based on a cut signal indicating that the first substrate has been cut and/or an adhesion signal indicating that the first substrate and the second substrate have been adhered to each other;
a print head retracting step of retracting the print head from the first and second substrates while the print head is transported a distance that is an integral multiple of a unit print length of repeated printing by the print head so that a cut piece of the first substrate and/or an adhesive piece of the first and second substrates do not come into contact with the print head when the joining position where the second substrate is joined passes through a printing position where ink is ejected by the print head;
Equipped with
The method further includes a cutting length detection step of detecting a cutting length from the joining position of the first substrate to be cut after the second substrate is joined,
The print head retracting step completes retraction of the print head after the splicing position and the cutting length have passed the printing position . A print control program for controlling a printing device having a print head that ejects ink onto a conveyed printing substrate,
an insertion detection step of detecting that a new second substrate has been inserted onto a first substrate being printed by the print head at an upstream stage in the transport direction of the print head, based on a cut signal indicating that the first substrate has been cut and/or an adhesion signal indicating that the first substrate and the second substrate have been adhered to each other;
a print head retracting step of retracting the print head from the first and second substrates while the print head is transported a distance that is an integral multiple of a unit print length of repeated printing by the print head so that a cut piece of the first substrate and/or an adhesive piece of the first and second substrates do not come into contact with the print head when the joining position where the second substrate is joined passes through a printing position where ink is ejected by the print head;
on the computer ,
The computer is further caused to execute a cutting length detection step of detecting a cutting length from the joining position of the first substrate to be cut after the second substrate is joined,
The print head retracting step is a print control program that ends retraction of the print head after the splicing position and the cutting length have passed the printing position .