Image formation device and image formation method

Abstract

To provide a technique of making it easy to determine presence or absence of positional deviation of printing in a printing medium.SOLUTION: An image formation device is configured to: acquire a first period from timing at which a first mark printed on a printing medium to be conveyed has been detected to timing at which the first mark reaches a printing position of a first printing part; and control the first printing part so as to print a second mark to be printed while being superimposed on the first mark on the printing medium, at timing at which the first period has elapsed from the timing at which the first mark has been detected.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to the imaging arts. [Background technology]

[0002] Conventionally, in an image forming system that prints print information such as images and characters on a substrate, printing is controlled using eye marks to detect the position of the substrate. In such an image forming system, misalignment between the substrate and the print information can occur due to paper vibration during transport. However, it can be difficult to distinguish whether this misalignment is due to the design, and it can be difficult to determine whether it is a misalignment. Patent Document 1 proposes a method in which a position recognition reference mark is provided on the substrate in advance, a print position confirmation mark is printed when the print information is printed, and the misalignment is detected from the positions of these two marks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-272089 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology disclosed in Patent Document 1 requires providing four position recognition reference marks around the printing area, which causes problems such as the time required to provide the position recognition reference marks and the space required to place the four marks. The present invention provides a technology that makes it easy to tell whether or not there is a printing misalignment on a print medium. [Means for solving the problem]

[0005] One aspect of the present invention is characterized by comprising an acquisition means for acquiring a first period from the time when a first mark printed on a transported printing medium is detected to the time when the first mark reaches the printing position of a first printing unit, and a printing control means for controlling the first printing unit to print a second mark to be printed over the first mark on the printing medium at a time when the first period has elapsed from the time when the first mark is detected. Effect of the Invention

[0006] According to the present invention, it is possible to provide a technique for easily determining whether or not there is misalignment of printing on a print medium. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an image forming system. [Diagram 2] FIG. 2 is a block diagram showing an example of the main configuration of an image forming system 200. [Diagram 3] 4 is a flowchart of the operation of the image forming apparatus 100. [Figure 4] 2 is a diagram showing the state of the roll paper 400 during printing by the image forming apparatus 100. FIG. [Diagram 5] 2 is a diagram showing the state of roll paper 500 during printing by image forming apparatus 100. FIG. [Figure 6] 2 is a diagram showing the state of roll paper 600 during printing by image forming apparatus 100. FIG. [Figure 7] 4 is a flowchart of the operation of the image forming apparatus 100. [Figure 8] 2 is a diagram showing the state of roll paper 800 during printing by image forming apparatus 100. FIG. [Figure 9] 4 is a flowchart of the operation of the image forming apparatus 100. [Figure 10] FIG. 4 is a diagram showing a positional deviation confirmation mark. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0009] [First embodiment] First, a configuration example of an image forming system according to this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the image forming system according to this embodiment includes a paper feeder 103, an image forming apparatus 100, a UI (user interface) operation panel 101, a control PC (personal computer) 114, and a paper discharge device 104.

[0010] First, the paper feeder 103 will be described. The paper feeder 103 is a device that supplies roll paper 110, which is continuous paper capable of continuous printing (image formation), to the downstream image forming apparatus 100. The paper feeder 103 rotates the paper tube of the roll paper 110 around a rotation axis 112, and transports the roll paper 110 wound around the paper tube toward the image forming apparatus 100 at a constant speed via multiple rollers (transport rollers, paper feed rollers, etc.) and a skew correction device 109. The roll paper 110 transported toward the image forming apparatus 100 is roll paper whose skew has been corrected by the skew correction device 109.

[0011] Next, the paper discharge device 104 will be described. The paper discharge device 104 is a device that winds up the roll paper 110 transported from the image forming apparatus 100 into a roll around a paper tube. For example, as shown in Fig. 1, in the paper discharge device 104, the roll paper 110 is wound around a paper tube of a rotating shaft 113 and held in a roll shape. In other words, the paper discharge device 104 is a device that rotates the rotating shaft 113 to wind up the roll paper 110 transported to the paper tube at a constant speed around the rotating shaft 113 as a roll paper product via multiple rollers (e.g., transport rollers, paper discharge rollers).

[0012] Next, the control PC 114 and the UI operation panel 101 will be described. The UI operation panel 101 has a touch panel screen, and can display a list of information (print job information) related to a print job and accept an operation from a user according to the control of the control PC 114. The control PC 114 displays a list of information (print job information) related to a print job received from an external device on the UI operation panel 101. When a user touches print job information of a print job to be input to the image forming apparatus 100 from the list of print job information displayed on the UI operation panel 101, the control PC 114 inputs a print job corresponding to the touched print job information to the image forming apparatus 100. After that, when a user touches a print start button displayed on the UI operation panel 101, the control PC 114 inputs an execution instruction for the print job input to the image forming apparatus 100 to the image forming apparatus 100. Note that a method for inputting a print job to the image forming apparatus 100 and causing it to execute printing based on the print job is not limited to a specific method.

[0013] Next, the image forming apparatus 100 will be described. Before the image forming apparatus 100 starts printing, the roll paper 110 is passed from the paper feeder 103 through the image forming apparatus 100 to the paper discharger 104. More specifically, the roll paper 110 is set in the paper feeder 103, and the leading edge of the roll paper 110 is passed over the oblique light corrector 109. Next, the leading edge of the roll paper 110 passes under the eye mark detector 115 and the printer 102 of the image forming apparatus 100, passes under the dryer 105, passes over the coolers 107 and 108, passes between the two scanners 106, and is wound around the paper discharger 104. After completing these operations, the image forming apparatus 100 is ready to print based on a print job.

[0014] When printing begins in the image forming apparatus 100, the roll paper 110 is transported from the paper feeder 103 into the image forming apparatus 100, moving from right to left along the x-axis (the transport direction of the roll paper 110), passing underneath the eye mark detector 115 and the printer 102 (downward along the z-axis). In Fig. 1, the y-axis is the direction (paper width direction) of the roll paper 110 that is perpendicular to the transport direction.

[0015] Eye mark detection device 115 detects eye marks printed on roll paper 110. Eye marks will be described later. Printing device 102 is located downstream of eye mark detection device 115 in the transport direction of roll paper 110. When a specified period of time has elapsed from the timing when eye mark detection device 115 detects an eye mark, printing device 102 prints a page based on the print job on roll paper 110 and also prints a misalignment confirmation mark corresponding to that page. The specified period of time and the misalignment confirmation mark will be described later.

[0016] Thereafter, the image and marks printed on the roll paper 110 are fixed to the roll paper 110 by the drying device 105 and the cooling devices 107 and 108. The scanner device 106 scans the roll paper 110. The image forming apparatus 100 detects the eye mark and the misalignment confirmation mark in the image obtained by the scan, calculates the amount of misalignment between the detected eye mark and the misalignment confirmation mark, and executes a specified process if the calculated amount of misalignment is equal to or greater than a threshold. The specified process may be any of a variety of processes and is not limited to a specific process. For example, the image forming apparatus 100 may interrupt the printing process and display on the UI operation panel 101 a message notifying the user of the interruption as well as a message indicating that the skew of the roll paper 110 has not been sufficiently corrected.

[0017] Next, an example of the main configuration related to each process described below in the image forming system 200 according to this embodiment will be described with reference to the block diagram in Fig. 2. The paper transport unit 201 is a transport mechanism for the roll paper 111 inside the image forming apparatus 100. For example, the paper transport unit 201 includes multiple rollers inside the image forming apparatus 100 and a motor that controls the rotation of the rollers. The multiple rollers of the paper transport unit 201 transport the roll paper 111 transported from the paper feeder 103 to the paper discharger 104.

[0018] The printing device 102 prints the page and a misalignment confirmation mark on the roll paper 110 transported from the paper feeder 103 by the paper transport unit 201. The communication unit 203 is, for example, a communication control card such as a LAN (Local Area Network) card. The communication unit 203 can transmit and receive various data to and from external devices (such as personal computers) connected to a communication network such as a LAN or a WAN (Wide Area Network).

[0019] The control unit 204 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), etc. The CPU of the control unit 204 reads out various programs such as a system program and a processing program stored in the storage unit 205, loads them in the RAM of the control unit 204, and executes various processes according to the loaded programs. For example, when the control unit 204 receives an instruction to execute a print job from the control PC 114, the control unit 204 controls the operation of each unit and executes the print job input from the control PC 114.

[0020] The storage unit 205 includes, for example, a non-volatile semiconductor memory (so-called flash memory), a HDD (Hard Disk Drive), etc. The storage unit 205 stores various programs including a system program and a processing program executed by the control unit 204, and various data required for executing these programs.

[0021] The operation display unit 206 is a functional unit including the control PC 114 and the UI operation panel 101. Note that the operation display unit 206 may also include various operation keys that the image forming apparatus 100 has, such as a numeric keypad, a start key, and the like.

[0022] The operation display unit 206 is used, for example, when executing a print job, to set print settings based on the print job. The user can operate the UI operation panel 101 or operation keys to set print settings such as the paper to be used, the print speed (the transport speed of the roll paper 110), the number of prints, the number of copies, the print length, the print weight, the print diameter, and the like.

[0023] The inspection unit 207 includes an eye mark detection device 115. The eye mark detection device 115 scans the roll paper 110 and performs detection processing to detect eye marks from the image obtained by the scan.

[0024] Next, the operation of image forming apparatus 100 according to this embodiment will be described with reference to the flowchart in Fig. 3. In step S300, control unit 204 acquires an unprinted page (image) that has not yet been printed based on the print job to be executed by expanding the page in RAM of control unit 204.

[0025] In step S301, the eye mark detection device 115 scans the roll paper 110 that has been transported from the paper feed device 103 into the image forming device 100 by the paper transport unit 201, and performs a detection process to detect an eye mark from the image obtained by the scan.

[0026] In step S302, when the eye mark detection device 115 detects an eye mark, the control unit 204 calculates the timing (print start timing) T2 at which the printing device 102 starts printing based on the detection timing (detection timing) T1.

[0027] For example, the control unit 204 obtains the distance L between the eye mark detection device 115 and the printing device 102 in the transport direction of the roll paper 110, and the transport speed v of the roll paper 110. The distance L is known and is stored in advance in the storage device 103. The transport speed v can be obtained from the print settings described above. The control unit 204 then obtains the period Δ between detection timing T1 and print start timing T2 as Δ=L / v. In other words, the control unit 204 obtains the period Δ from the timing when an eye mark printed on the transported roll paper 110 is detected to the timing when the eye mark reaches the printing position of the printing device 102.

[0028] The period Δ may be calculated in advance and stored in the storage device 103 before the start of the processing according to the flowchart in FIG.

[0029] The control unit 204 then determines the print start timing T2 by calculating T2 = T1 + Δ. Note that, taking into account time ε, such as the time from when the printing device 102 starts to eject ink to when ink actually adheres to the roll paper 110, the period Δ may be calculated by subtracting time ε from the above period Δ.

[0030] In step S303, the control unit 204 controls (print controls) the printing device 102 to print, at the printing start timing (the timing when the period Δ has elapsed from the detection timing T1), the page acquired in the RAM in step S300 and the misalignment confirmation mark that has been preloaded from the storage device 103 to the RAM. This enables the printing device 102 to print the page and the misalignment confirmation mark on the roll paper 110 at the printing start timing.

[0031] In step S304, the control unit 204 determines whether all pages have been printed based on the print job to be executed. If the result of this determination is that all pages have been printed, the process according to the flowchart in Fig. 3 ends. On the other hand, if there are pages that have not yet been printed, the process proceeds to step S300.

[0032] FIG. 4 shows the state of roll paper 400 during printing by image forming apparatus 100. A base 401 and eye marks 402 are printed on roll paper 400 in advance. Base 401 is an area for printing images and characters, and in FIG. 4, two bases 401 are printed along the y-axis direction for each page. An eye mark is a mark that is detected by a reflection sensor, which is eye mark detection device 115, and is used to ensure printing without misalignment. In FIG. 4, the eye mark is a rectangle filled with white, and is printed near the downstream end of the base of each page in the transport direction.

[0033] Such a roll paper 400 is transported in the transport direction. When the eyemark detection device 115 detects the eyemark 402, the control unit 204 calculates the period Δ from the detection timing until the eyemark 402 moves to the printing position of the printing device 102 (the position of the printing device 102 on the x-axis) as described above. The control unit 204 then calculates the timing obtained by adding the period Δ to the detection timing T1 at which the eyemark detection device 115 detected the eyemark 402 as the above-mentioned print start timing T2. The printing device 102 then prints the page and the misalignment confirmation mark at the print start timing (the timing when the period Δ has elapsed since the detection timing T1).

[0034] Here, the misregistration confirmation mark is a mark for printing overlaid with the eye mark. Since the position of the eye mark on the roll paper in the paper width direction is fixed, the nozzle for printing the misregistration confirmation mark is the nozzle corresponding to the position of the eye mark on the roll paper. Therefore, when the roll paper 400 is not displaced in the y-axis direction (for example, when the skew of the roll paper 400 is sufficiently corrected by the skew correction device 109), as in the first page, the misregistration confirmation mark 406 is printed overlapping the eye mark 402. Also, as in the first page, the page 405 is printed within the base 401.

[0035] However, when the roll paper 400 is displaced in the y-axis direction (for example, when the skew of the roll paper 400 is not sufficiently corrected by the skew correction device 109), as in the second page, the misregistration confirmation mark 406 is printed at a position displaced from the eye mark 402. Also, the page 405 is printed at a position displaced from the original printing position indicated by the dotted line within the base 401.

[0036] In FIG. 4, a mark having a "field" shape is used as the misregistration confirmation mark. However, any shape of mark can be used as the misregistration confirmation mark as long as it is a mark whose misregistration with the eye mark can be confirmed when printed, such as a mark having squares at the four corners, a mark represented by a plurality of vertical / horizontal / diagonal lines, a circular or elliptical mark, etc.

[0037] [Second Embodiment] In the following embodiments including this embodiment, the differences from the first embodiment will be described, and unless otherwise specifically mentioned below, it is assumed to be the same as the first embodiment. In this embodiment, the roll paper conveyed to the image forming apparatus 100 does not have the base and the eye mark printed thereon. After the image forming apparatus 100 prints the base and the eye mark, the page and the misregistration confirmation mark are printed in the same manner as in the first embodiment. Therefore, this embodiment has a first printing device for printing the base and the eye mark, and a second printing device for printing the page and the misregistration confirmation mark.

[0038] FIG. 5 shows the state of roll paper 500 during printing by the image forming apparatus 100. Neither a base nor eyemarks are printed on the roll paper 500. Such roll paper 500 is transported in the transport direction. The base printing unit 507, which is the first printing device, prints a base 501 and eyemarks 502 on the transported roll paper 500. The positional relationship between the base and the eyemarks is the same as in the first embodiment. When the eyemark detection device 115, located downstream in the transport direction from the base printing unit 507, detects the eyemark 502, the control unit 204 determines the period Δ until the eyemark 502 moves to the printing position of the mark printing unit 504, which is the second printing device (the position of the mark printing unit 504 on the x-axis), in the same manner as in the first embodiment. The control unit 204 then determines the timing obtained by adding the period Δ to the detection timing T1 at which the eyemark detection device 115 detects the eyemark 502, as the above-mentioned print start timing T2. Then, the mark printing unit 504 prints a page 505 and a misalignment check mark 506 at the print start timing (the timing when the period Δ has elapsed from the detection timing T1).

[0039] [Third embodiment] In this embodiment, we will explain a case in which, if the amount of misalignment between the misalignment confirmation mark and the eye mark is within a threshold value, it is determined that the misalignment confirmation mark / the page corresponding to the eye mark has been printed correctly, and the misalignment confirmation mark is filled in.

[0040] Fig. 6 shows the state of roll paper 600 during printing by image forming apparatus 100. In this embodiment, as shown in Fig. 6, in addition to eye mark detection device 115, inspection unit 207 has inspection unit 608 located downstream of printing device 102 in the transport direction, and printing unit 607 located downstream of inspection unit 608 in the transport direction.

[0041] A base 601 and an eye mark are printed in advance on the roll paper 600. Such roll paper 600 is transported in the transport direction. When the eye mark detection device 115 detects the eye mark, the printing device 102 prints a page 605 and a misalignment confirmation mark 606 at the start of printing, as in the first embodiment.

[0042] The inspection unit 608 scans the vicinity of the eye mark, and detects the eye mark and the misalignment confirmation mark from the image obtained by the scan. The control unit 204 then judges whether the amount of misalignment between the eye mark and the misalignment confirmation mark is within a threshold value. If the amount of misalignment is within the threshold value as a result of this judgment, the control unit 204 judges that there is no misalignment between the eye mark and the misalignment confirmation mark, and calculates the timing (print start timing) T4 at which the printing unit 607 starts printing based on the detection timing (detection timing) T3.

[0043] For example, the control unit 204 acquires the distance L1 between the inspection unit 608 and the printing unit 607 in the transport direction of the roll paper 600, and the transport speed v of the roll paper 600. The distance L1 is known and is stored in advance in the storage device 103. The transport speed v can be acquired from the print settings described above. The control unit 204 then acquires the period Δ1 between the detection timing T3 and the print start timing T4 as Δ1=L1 / v. In other words, the control unit 204 acquires the period Δ1 from the timing at which the eye mark and the misalignment confirmation mark printed on the transported roll paper 600 are detected to the timing at which the eye mark / the misalignment confirmation mark arrive at the printing position of the printing unit 607. The period Δ1 may be acquired in advance and stored in the storage device 103. In this case, the control unit 204 reads out the period Δ1 stored in the storage device 103.

[0044] The control unit 204 then determines the print start timing T4 by calculating T4 = T3 + Δ1. Note that, taking into consideration time ε1, such as the time from when the printing unit 607 starts to eject ink to when ink actually adheres to the roll paper 600, the period Δ1 may be calculated by subtracting time ε1 from the above period Δ1.

[0045] The control unit 204 then instructs the printing unit 607 to print a fill-in mark, which is a mark for filling in the misalignment confirmation mark, at print start timing T4 (the timing when period Δ1 has elapsed since detection timing T3). Because the position of the eye mark on the roll paper in the paper width direction is fixed, the nozzles that print the fill-in mark are the nozzles that correspond to the position of the eye mark on the roll paper. Upon receiving this instruction, the printing unit 607 prints the fill-in mark.

[0046] On the other hand, if the amount of positional deviation between the eye mark and the positional deviation confirmation mark is not within the threshold value, the control unit 204 does not instruct the printing unit 607 to print a fill mark.

[0047] Therefore, on the first and third pages, the amount of misalignment between the eye mark and the misalignment confirmation mark is within the threshold, so the fill mark 606 is printed. On the second page, the amount of misalignment between the eye mark and the misalignment confirmation mark is not within the threshold, so the fill mark 606 is not printed.

[0048] In this embodiment, the fill-in mark is a black rectangle for filling in the misalignment confirmation mark, but the shape and color of the fill-in mark are not limited to a specific shape or color as long as it can fill in the misalignment confirmation mark. Also, the fill-in mark does not have to be a mark for completely filling in the misalignment confirmation mark, and may be, for example, a stamp with specific characters written on it or a stamp with a cross.

[0049] The operation of the image forming apparatus 100 according to this embodiment will be described with reference to the flowchart of Fig. 7. In the flowchart of Fig. 7, the same process steps as those shown in Fig. 3 are given the same step numbers, and the description of those process steps will be omitted.

[0050] As shown in Fig. 7(a), processing relating to printing of a fill-in mark is carried out in step S700. Details of the processing in step S700 will be described with reference to the flowchart in Fig. 7(b).

[0051] In step S710, the inspection unit 608 detects the eye mark and the misalignment confirmation mark from the image obtained by scanning the roll paper 110. Then, in step S720, the control unit 204 determines whether the amount of misalignment between the eye mark and the misalignment confirmation mark is within a threshold value.

[0052] If the result of this determination is that the amount of positional deviation between the eye mark and the positional deviation confirmation mark is within the threshold, the process proceeds to step S730. On the other hand, if the amount of positional deviation between the eye mark and the positional deviation confirmation mark is not within the threshold, the process proceeds to step S340.

[0053] In step S730, the control unit 204 determines the print start timing T4 based on the detection timing T3 as described above. Then, in step S740, the control unit 204 instructs the printing unit 607 to print a fill mark at the print start timing T4. Upon receiving this instruction, the printing unit 607 prints the fill mark.

[0054] [Fourth embodiment] In this embodiment, when misalignment between the eye mark and the misalignment confirmation mark occurs continuously for a certain period of time, the page and the print position of the misalignment confirmation mark are corrected according to the amount of misalignment.

[0055] Fig. 8 shows the state of roll paper 800 during printing by the image forming apparatus 100. In this embodiment, as shown in Fig. 8, the inspection unit 207 has, in addition to the eye mark detection device 115, an inspection unit 608 located downstream of the printing device 102 in the transport direction.

[0056] A base 801 and an eye mark are printed in advance on the roll paper 600. Such roll paper 800 is transported in the transport direction. When the eye mark detection device 115 detects an eye mark, the printing device 102 prints a page 805 and a misalignment confirmation mark 806 at the start of printing, as in the first embodiment.

[0057] The inspection unit 608 detects the eye mark and the misalignment confirmation mark from the image obtained by scanning. Then, the control unit 204 judges whether or not the misalignment amount between the eye mark and the misalignment confirmation mark is within a threshold value. If the result of this judgment is that the misalignment amount is within the threshold value, the control unit 204 increments the counter value by one. The initial value of the counter value is 0, and if the control unit 204 judges that the misalignment amount between the eye mark and the misalignment confirmation mark is not within the threshold value, it initializes the counter value to 0. In other words, the counter value indicates the number of times (number of pages) that it has been consecutively judged that the misalignment amount between the eye mark and the misalignment confirmation mark is within the threshold value.

[0058] When the counter value is equal to or greater than the threshold value, the control unit 204 changes the printing positions of the page and the misalignment confirmation mark so that the misalignment amount between the eye mark and the misalignment confirmation mark becomes zero. For example, in the case of FIG. 8, the misalignment confirmation mark is printed shifted upward with respect to the eye mark from the first page to the third page. In the example of FIG. 8, the threshold value is set to 4, so the control unit 204 corrects the printing positions of the page and the misalignment confirmation mark downward by a shift amount according to the misalignment amount so that the misalignment amount becomes zero from the fourth page onward. The shift amount may be, for example, an average value of the misalignment amounts calculated for the first to third pages, or any of the misalignment amounts calculated for the first to third pages.

[0059] The operation of the image forming apparatus 100 according to this embodiment will be described with reference to the flowchart of Fig. 9. In the flowchart of Fig. 9, the same process steps as those shown in Fig. 3 and Fig. 7 are given the same step numbers, and the description of those process steps will be omitted.

[0060] As shown in Fig. 9A, in step S901, the page and the printing position of the misalignment check mark are controlled. Details of the process in step S901 will be described with reference to the flowchart in Fig. 9B.

[0061] In this embodiment, if the result of the determination in step S720 is that the amount of positional deviation between the eye mark and the positional deviation confirmation mark is within the threshold, the process proceeds to step S912. On the other hand, if the amount of positional deviation between the eye mark and the positional deviation confirmation mark is not within the threshold, the process proceeds to step S911. In step S911, the control unit 204 increments the counter value by one.

[0062] In step S912, the control unit 204 determines whether the counter value is equal to or greater than the threshold value. If the counter value is equal to or greater than the threshold value, the process proceeds to step S913. If the counter value is less than the threshold value, the process proceeds to step S304. In step S913, the control unit 204 changes the page and the print position of the misalignment confirmation mark so that the amount of misalignment between the eye mark and the misalignment confirmation mark becomes zero.

[0063] [Fifth embodiment] By printing the misalignment check mark with ink of a different color, it becomes possible to check whether there is any misalignment specific to the head. The misalignment check mark according to this embodiment will be described with reference to FIG.

[0064] In FIG. 10, misalignment confirmation mark 1000 is the misalignment confirmation mark employed in the above embodiment, and all parts are printed in the same color. On the other hand, misalignment confirmation mark 1001 is the misalignment confirmation mark according to this embodiment. In the misalignment confirmation mark 1001, a line segment 1002 is printed in cyan ink, a line segment 1003 is printed in magenta ink, a line segment 1004 is printed in yellow ink, and a line segment 1005 is printed in black ink. By using such a misalignment confirmation mark, it is possible to check whether printing by a specific ink head is misaligned. Note that the colors of the line segments are not limited to the above colors. Furthermore, the shape of the misalignment confirmation mark, each part of which is printed in a different color, is not limited to a specific shape.

[0065] In addition, in each of the above embodiments, the case where the print medium is roll paper has been described, but this is not limited thereto, and it may be paper of a size such as A4, A5, B5, etc. In this case, each paper corresponds to each of the above pages.

[0066] The numerical values, processing timing, processing order, processing subject, data (information) acquisition method / destination / source / storage location, etc. used in each of the above embodiments are given as examples to provide a concrete explanation, and are not intended to be limited to these examples.

[0067] In addition, a part or all of the embodiments described above may be used in appropriate combination. In addition, a part or all of the embodiments described above may be used selectively.

[0068] (Other embodiments) The present disclosure can also be realized by a process in which a program for implementing one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0069] The invention of this specification includes the following image forming apparatus and method for controlling the image forming apparatus. (Item 1) an acquisition means for acquiring a first period from a timing when a first mark printed on the transported print medium is detected to a timing when the first mark reaches a printing position of a first printing unit; a print control means for controlling the first printing unit to print a second mark, which is to be printed over the first mark, on the print medium at a timing when the first period has elapsed from a timing when the first mark is detected; An image forming apparatus comprising: (Item 2) 2. The image forming apparatus according to item 1, wherein the print control means further controls a second printing unit to print the first mark on the print medium being transported. (Item 3) The image forming apparatus described in item 1 or 2, characterized in that the printing control means detects the first mark and the second mark on the printing medium, and when it is determined that there is no positional misalignment between the first mark and the second mark, obtains a second period from the time of the detection to the time when the first mark reaches the printing position of the third printing unit, and controls the third printing unit to print a third mark to be printed over the second mark on the printing medium at a time when the second period has elapsed from the time of the detection. (Item 4) The image forming apparatus according to any one of items 1 to 3, characterized in that when the number of consecutive pages on which it has been determined that there is a positional misalignment between the first mark and the second mark is equal to or greater than a threshold value, the print control means changes the printing position of the second mark on the printing medium based on the amount of misalignment. (Item 5) 5. The image forming apparatus according to any one of items 1 to 4, wherein the print control means prints each portion of the second mark in a different color. (Item 6) 6. The image forming apparatus according to claim 1, wherein the print medium is roll paper. (Item 7) A control method for an image forming apparatus, comprising: an acquisition step of acquiring a first period from a timing when an acquisition means of the image forming apparatus detects a first mark printed on the transported print medium to a timing when the first mark reaches a printing position of a first printing unit; a print control step in which a print control means of the image forming apparatus controls the first printing unit to print a second mark to be printed over the first mark on the print medium at a timing when the first period has elapsed from a timing of detecting the first mark; 11. A method for controlling an image forming apparatus comprising:

[0070] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0071] 101: UI operation panel 102: Printing device 103: Paper feed device 104: Paper discharge device 114: Control PC 200: Image forming system 201: Paper transport section 203: Communication section 204: Control section 205: Storage section 206: Operation display section 207: Inspection section

Claims

1. An acquisition means for acquiring a first period from the moment a first mark printed on the transported printing medium is detected until the moment the first mark reaches the printing position of the first printing section, A printing control means controls the first printing unit to print a second mark on the printing medium at a time when the first period has elapsed from the time the first mark is detected, in order to print a second mark on top of the first mark. An image forming apparatus characterized by comprising:

2. The image forming apparatus according to claim 1, further characterized in that the printing control means controls the second printing unit to print the first mark on the conveyed printing medium.

3. The image forming apparatus according to claim 1, characterized in that the printing control means detects the first mark and the second mark on the printing medium, and if it is determined that there is no misalignment between the first mark and the second mark, it obtains a second period from the timing of the detection to the timing when the first mark reaches the printing position of the third printing unit, and controls the third printing unit to print the third mark on the printing medium at the timing when the second period has elapsed from the timing of the detection.

4. The image forming apparatus according to claim 1, characterized in that, if the number of consecutive pages on which a misalignment between the first mark and the second mark is determined to occur exceeds a threshold, the printing control means changes the printing position of the second mark on the printing medium based on the amount of the misalignment.

5. The image forming apparatus according to claim 1, characterized in that the printing control means prints each part of the second mark in a different color.

6. The image forming apparatus according to claim 1, characterized in that the printing medium is roll paper.

7. A method for controlling an image forming apparatus, The acquisition step includes an acquisition step in which the acquisition means of the image forming apparatus acquires a first period from the timing when it detects a first mark printed on the conveyed printing medium to the timing when the first mark reaches the printing position of the first printing section, The printing control means of the image forming apparatus controls the first printing unit to print a second mark on top of the first mark onto the printing medium at a time when the first period has elapsed from the time the first mark was detected; A control method for an image forming apparatus, characterized by comprising the following:

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