Printing apparatus, method for controlling the printing apparatus, and program

Abstract

To improve the throughput of printing equipment. [Solution] The printing apparatus comprises a transport device for transporting a printing medium, a liquid ejection head 151 for ejecting liquid onto the printing medium to print an image, a fixing device 154 for fixing the liquid ejected onto the printing medium, a maintenance device for performing maintenance on the liquid ejection head 151, and a controller for obtaining the length of the margin between the first image and the second image when it is planned to print a second image after the first image for which the liquid has been fixed by the fixing device 154. The controller causes the maintenance device to perform maintenance in parallel with the fixing of the liquid in the first image by the fixing device 154 if the margin length is a first length, and does not cause the maintenance device to perform maintenance if the margin length is a second length which is shorter than the first length.

Description

Technical Field

[0001] The present disclosure relates to a printing apparatus, a control method for the printing apparatus, and a program.

Background Art

[0002] An inkjet printing apparatus, which is an example of a printing apparatus, prints an image on a print medium by ejecting a liquid such as ink from a liquid ejection head. When printing an image with the liquid ejection head, dirt such as fixed ink accumulates on the liquid ejection head. When dirt such as fixed ink accumulates on the liquid ejection head, the print medium may become dirty, or the supply of ink to the nozzles of the liquid ejection head may be hindered, resulting in non-ejection of ink. In order to suppress dirt on the print medium, non-ejection of ink, etc. caused by dirt accumulating on the liquid ejection head, it is necessary to periodically perform maintenance on the liquid ejection head.

[0003] The printing apparatus cannot perform printing during maintenance of the liquid ejection head. For this reason, as the number of maintenance operations increases, the printable time by the printing apparatus decreases, and the throughput of the printing apparatus decreases. Patent Document 1 discloses a technique for determining the timing of a flushing operation so that more image printing is performed as the time interval between image prints per page is shorter during the printable period. Note that the printable period is the period from when a flushing operation for ejecting a liquid from the liquid ejection head is executed until the next flushing operation is executed. Thereby, it is possible to reduce the number of flushing operations, which is a kind of maintenance of the liquid ejection head.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technology disclosed in Patent Document 1 may not be able to sufficiently reduce the number of maintenance cycles. For example, when printing multiple images where the spacing between them does not change significantly, or when maintenance is required after each print due to factors such as the print content and environment, the number of maintenance cycles may not be sufficiently reduced. In such cases, if the number of maintenance cycles cannot be sufficiently reduced, the throughput of the printing device may decrease.

[0006] This disclosure aims to improve the throughput of printing equipment. [Means for solving the problem]

[0007] A printing apparatus according to one aspect of the present disclosure comprises a transport device for transporting a printing medium, a liquid discharge head for discharging liquid onto the printing medium transported by the transport device to print an image, a fixing device for fixing the liquid discharged onto the printing medium by the liquid discharge head, a maintenance device for performing maintenance on the liquid discharge head, and a controller for acquiring the length of the margin between the first image and the second image along the transport direction on the printing medium when it is planned to print a second image after a first image on which the liquid is fixed by the fixing device, wherein the controller causes the maintenance device to perform the maintenance in parallel with the fixing of the liquid on the first image by the fixing device when the margin length is a first length, and does not cause the maintenance device to perform the maintenance when the margin length is a second length which is shorter than the first length. [Effects of the Invention]

[0008] According to this disclosure, the throughput of a printing device can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram illustrating the schematic configuration of a printing apparatus. [Figure 2] This is a schematic cross-sectional view of a printing apparatus. [Figure 3] This is a schematic diagram of a printing machine viewed from the front. [Figure 4] This is a schematic diagram showing the configuration of the suction mechanism. [Figure 5] This is a schematic diagram showing the configuration of the wiping mechanism. [Figure 6] This is a schematic diagram showing the maintenance confirmation screen for a printing device. [Figure 7] This is a schematic diagram showing the maintenance confirmation screen for an external device. [Figure 8] This is a flowchart showing the control method for the printing apparatus in the first embodiment. [Figure 9] This is an explanatory diagram that compares the length of the margin between the first and second images with the maintenance transport length. [Figure 10] This is a flowchart showing the control method for the printing apparatus in the second embodiment. [Figure 11] This is an explanatory diagram that compares the length of the margin between the first image and the second image with the length of the margins between each of the subsequent images. [Modes for carrying out the invention]

[0010] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings. However, the following embodiments are not limiting to the scope of this disclosure, and not all combinations of features described in the following embodiments are necessarily essential to the solutions of this disclosure. Furthermore, the relative arrangement of the components of the apparatus used in the following embodiments, the apparatus shape, etc., are merely illustrative and not limiting. The same components will be denoted by the same reference numerals.

[0011] <<First Embodiment>> <Printing device configuration> Figure 1 is a block diagram showing the schematic configuration of the printing device 100 according to this embodiment. In this embodiment, the printing device 100 has only a printing function, but is not limited thereto. For example, the printing device may function as a copier further equipped with a reading device for reading images on a document, or it may function as a multi-function device (MFP: Multi-Function Peripheral) with additional functions.

[0012] As shown in Figure 1, the printing device 100 comprises a printer controller 120, a printer engine 150, an HDD 161, and an input / output device 162. The printing device 100 can also be connected to a host computer 190 via a network 191. The printer controller 120 has an HDD interface (I / F) 121, an input / output device interface (I / F) 122, a ROM interface (I / F) 125, and a memory controller 126. The printer controller 120 also has a host interface (I / F) 127, a CPU 128, a printer interface (I / F) 129, and an image processing unit 130. Each interface, such as the HDD interface 121, the memory controller 126, the CPU 128, and the image processing unit 130 are connected via a system bus 132. Furthermore, the printer controller 120 has a Flash ROM 123 and a RAM 124. The FlashROM 123 is connected to the system bus 132 via the ROM interface 125, and the RAM 124 is connected to the system bus 132 via the memory controller 126.

[0013] The CPU (Central Processing Unit) 128 is a central arithmetic processing unit in the form of a microprocessor (microcomputer), and controls the overall operation of the printing apparatus 100 by executing a program or starting up the hardware. The Flash ROM 123 stores programs for the CPU 128 to execute and various data necessary for various operations of the printing apparatus 100. The RAM (Random Access Memory) 124 is used as a work area for the CPU 128, as a temporary storage area for various received data, or to store various setting data.

[0014] The image processing unit 130 performs various image processes. For example, the image processing unit 130 performs a process of expanding (converting) print data handled by the printing apparatus 100 into image data (bitmap image data). The print data handled by the printing apparatus 100 is, for example, data represented in a page description language. Also, the image processing unit 130 converts the color space (e.g., YCbCr) of the image data included in the input print data into a standard RGB color space (e.g., sRGB). Further, the image processing unit 130 performs various image processes such as resolution conversion to an effective number of pixels (printable by the printing apparatus 100), image analysis, and image correction on the image data as necessary. The image data obtained by these image processes is stored in the RAM 124 or the HDD 161.

[0015] The printer engine 150 is the printing unit that prints images. The printer engine 150 comprises a liquid ejection head 151, a cutter unit 152, a transport motor 153, a fuser unit 154, a controller interface (I / F) 155, and an optical sensor 156. The printer engine 150 also comprises a suction mechanism 170 having a cap 171 and a suction pump 172 (see Figure 4 below) and a wiping mechanism 180 having a wiper 181 (see Figure 5 below). The liquid ejection head 151, cutter unit 152, transport motor 153, fuser unit 154, controller interface 155, optical sensor 156, cap 171, suction pump 172, and wiper 181 are connected via a system bus 157. The controller interface 155 is electrically connected to a printer interface 129 provided on the printer controller 120.

[0016] The liquid ejection head 151 prints an image onto a roll of paper, which is the printing medium, based on image data obtained by the image processing unit 130. The liquid ejection head 151 prints an image onto the roll of paper by ejecting liquid such as ink from the nozzles of the liquid ejection unit 151A (see Figure 4, described later) in synchronization with the transport of the roll of paper by the transport motor 153. The liquid ejection unit 151A is provided with multiple rows of nozzles corresponding to multiple types of ink. The printing apparatus 100 according to this embodiment is an inkjet type printing apparatus that performs printing by ejecting ink using the liquid ejection head 151.

[0017] The cutter unit 152 is a mechanism for cutting (severing) roll paper. The cutter unit 152 cuts the roll paper after printing an image to a predetermined length. When the paper type of the roll paper is a type that scatters paper dust during cutting by the cutter unit 152, in order to prevent the scattering of paper dust during cutting, a setting for drawing a cut waste reduction line at the cutting position of the roll paper is stored in the FlaShROM 123. Also, independently of the setting for drawing the cut waste reduction line, the operation settings of the cutter unit 152 for each paper type of the roll paper may be stored in the FlaShROM 123. For example, when the paper type of the roll paper is a type that cannot be cut using the cutter unit 152, since the user cuts the roll paper using scissors, a setting for not operating the cutter unit 152 is stored in the FlaShROM 123. The setting for not operating the cutter unit 152 is also referred to as user cutting. Also, when the paper type of the roll paper is a type whose cutting line will bend unless the user holds down the roll paper during cutting, a setting for operating the cutter unit 152 by the user's operation is stored in the FlaShROM 123. The setting for operating the cutter unit 152 by the user's operation is also referred to as eject cut. When the paper type of the roll paper is a type for which neither the user cutting nor the eject cut setting is performed, a setting for automatically cutting the roll paper by the cutter unit 152 is stored in the FlaShROM 123. The setting for automatically cutting the roll paper by the cutter unit 152 is also referred to as auto cut.

[0018] The conveyance motor 153 is a motor for driving a conveyance roller 205 (see FIG. 2 described later) that conveys roll paper. The conveyance motor 153 is controlled by the CPU 128. The optical sensor 156 is a reflection type optical sensor including an LED (Light Emitting Diode) as a light emitting element, a regular reflection light receiving element, a diffused reflection light receiving element, and the like. The optical sensor 156 is also a measuring instrument for measuring the attribute values of roll paper. The printing apparatus 100 uses the optical sensor 156 to measure the intensities of the regular reflection light and the diffused reflection light from the roll paper positioned on the platen 211 (see FIG. 2 described later), and attribute values such as the thickness of the roll paper.

[0019] The fixing device 154 is a device for drying the roll paper. The fixing device 154 dries and fixes the ink on the roll paper by applying hot air to the roll paper on which the image has been printed. The roll paper, with the ink fixed, is transported by the transport device, which consists of a transport motor 153 and transport rollers 205, and cut as needed by the cutter unit 152.

[0020] The HDD (Hard Disk Drive) 161 is a non-volatile storage device. It can store programs for execution by the CPU 128, print data, and setting information necessary for various operations of the printing device 100, and can also be read from the HDD 161. Note that other high-capacity storage devices, such as flash memory, may be used instead of the HDD 161.

[0021] The input / output device 162 includes hard keys or a panel for the user to perform various operations, and a display device (notified) for displaying (notifying) the user of various information. The display device is configured, for example, using a touch panel. The input / output device 162 may also notify the user of information by generating sound (e.g., a buzzer sound, voice, etc.) based on acoustic information using an acoustic generator. When feeding paper, the user performs an operation to input the type of roll paper to the input / output device 162, and the printing device 100 can transport the roll paper set for each paper type.

[0022] In this embodiment, the input / output device 162 is provided on the printing device 100, but is not limited to this. For example, the input / output device may be connected to the printing device via the network 191 as an external component. Alternatively, the host computer 190 may also function as an input / output device. Furthermore, in addition to the input / output device 162, other input / output devices may be connected to the printing device 100 via the network 191 or the like.

[0023] The host computer 190 is an external device such as a PC (Personal Computer) that serves as a source of print data. A printer driver is installed on the host computer 190. Instead of the host computer 190, the printing device 100 may be connected to a data supply device that serves as a source of print data, such as an image reader, a digital camera, or a smartphone. The connection method between each device and the printing device 100 is not limited to a connection method via the network 191. For example, the connection method between each device and the printing device 100 may be a direct connection method via wireless communication.

[0024] Figure 2 is a schematic cross-sectional view of the printing apparatus 100 according to this embodiment. Figure 2 shows the part related to the transport of the roll paper P, which is the printing medium. Also, in Figures 2 to 5, the Z direction represents the vertical direction and intersects (orthogonal in this embodiment) with the XY plane defined by the X and Y directions.

[0025] As shown in Figure 2, the printing apparatus 100 according to this embodiment further comprises a paper feeding unit 201, a transport roller 205, and a platen 211. A roll of paper P is placed in the paper feeding unit 201. The transport roller 205 and the platen 211 are located inside the printing apparatus 100. When the printing apparatus 100 feeds paper, the roll of paper P placed in the paper feeding unit 201 is transported along the transport path to the platen 211 by a transport device consisting of a transport motor 153 and transport roller 205. A liquid ejection head 151 and an optical sensor 156 are positioned inside the printing apparatus 100, facing the platen 211. The liquid ejection head 151 prints an image by ejecting ink onto the roll of paper P on the platen 211. The printing apparatus 100 uses the optical sensor 156 to measure the intensity of specular and diffuse reflected light from the roll of paper P located on the platen 211, the thickness of the roll of paper P, and the width of the roll of paper P. A fuser 154 and a cutter unit 152 are located outside the printing device 100. After the ink on the printed roll paper P is fixed by the fuser 154, the cutter unit 152 cuts it to the desired length. The liquid ejection head 151 is mounted on a carriage (not shown) and is capable of reciprocating in the main scanning direction (X direction) which intersects (orthogonal in this embodiment) with the transport direction of the roll paper P. Alternatively, both the fuser 154 and the cutter unit 152, or only the fuser 154, may be located inside the printing device 100.

[0026] Figure 3 is a schematic diagram of the printing apparatus 100 viewed from the front. Figure 3 shows the positional relationship between the platen 211, the liquid ejection head 151, the suction mechanism 170, and the wiping mechanism 180. For the sake of simplicity, the liquid ejection head 151, the suction mechanism 170, and the wiping mechanism 180 are shown in a simplified form in Figure 3.

[0027] As shown in Figure 3, the suction mechanism 170 and the wiping mechanism 180 are positioned near the side of the platen 211 on the -X side. The suction mechanism 170 and the wiping mechanism 180 constitute a maintenance device that performs maintenance on the liquid ejection head 151 in order to restore its performance. The liquid ejection head 151 prints an image by ejecting ink onto the roll paper P on the platen 211 while moving in the main scanning direction (X direction) above the platen 211. The liquid ejection head 151 moves to a position opposite the suction mechanism 170 to perform nozzle suction processing as needed, and moves to a position opposite the wiping mechanism 180 to perform wiping. Note that the number and arrangement of the suction mechanism 170 and the wiping mechanism 180 are merely examples and are not limited thereto.

[0028] Figure 4 is a schematic diagram showing the configuration of a suction mechanism 170 that performs nozzle suction processing to suck ink from the nozzle of the liquid ejection head 151 (liquid ejection section 151A). As shown in Figure 4, the suction mechanism 170 comprises a cap 171 and a suction pump 172. The cap 171 is a unit that covers the liquid ejection section 151A of the liquid ejection head 151. When the liquid ejection head 151 moves to a position facing the suction mechanism 170, the cap 171 moves upward (+Z direction) in response to an instruction from the printer engine 150, and caps the surface of the liquid ejection section 151A. When the suction pump 172 is activated with the cap 171 covering the surface of the liquid ejection section 151A, ink is sucked from the nozzle of the liquid ejection section 151A and stored in the waste liquid tank 179 through the tube 173. Furthermore, the ink stored in the waste liquid tank 179 is usually disposed of by the user when the waste liquid tank 179 is full of ink, but this is not the only way to do so.

[0029] Figure 5 is a schematic diagram showing the configuration of a wiping mechanism 180 that wipes off ink adhering to the surface of the liquid discharge head 151 (liquid discharge section 151A). The wiping mechanism 180 includes a wiper 181. The wiper 181 is a unit for wiping off ink adhering to the surface of the liquid discharge section 151A (nozzle) of the liquid discharge head 151. The wiper 181 is formed using an absorbent material such as nonwoven fabric. When the liquid discharge head 151 moves to a position facing the wiping mechanism 180, the wiper 181 moves to the wiping start position. The wiper 181 wipes off the ink adhering to the surface of the liquid discharge section 151A by moving from the wiping start position in the direction of travel (-X direction) indicated by arrow 185 in Figure 5.

[0030] Furthermore, the wiper 181 is not limited to absorbent materials such as nonwoven fabric, but may also be formed into a blade shape using, for example, a rubber material. The wiper 181 may move not only in the X direction but also in the Y direction to wipe away ink adhering to the surface of the liquid discharge section 151A (nozzle). Alternatively, instead of the wiper 181, the liquid discharge head 151 may move in the X direction to wipe away ink adhering to the surface of the liquid discharge section 151A.

[0031] Figure 6 is a schematic diagram showing the maintenance confirmation screen in the printing device 100. The maintenance confirmation screen is a screen for confirming with the user whether or not to perform maintenance. The maintenance confirmation screen in the printing device 100 is displayed on a display device (not shown) that constitutes the input / output device 162. The maintenance confirmation screen in the printing device 100 is arranged with a panel display unit 301, an execution permission touch unit 302, and an execution rejection touch unit 303. The panel display unit 301 displays guidance regarding the confirmation of whether or not maintenance can be performed. For example, the panel display unit 301 displays guidance text prompting the user to input whether or not maintenance can be performed, or displays the details of the maintenance. The execution permission touch unit 302 and the execution rejection touch unit 303 display areas on the maintenance confirmation screen that the user can touch. If the user views the panel display unit 301 and wishes to permit the maintenance to be performed, they touch the execution permission touch unit 302 to cause the printing device 100 to perform the maintenance. If a user who has viewed the panel display unit 301 wishes to refuse maintenance, they can stop the maintenance on the printing device 100 by touching the refuse touch unit 303.

[0032] Figure 7 is a schematic diagram showing a maintenance confirmation screen on an external device (not shown). The external device is, for example, a PC equipped with an output display device and is connected to the printing device 100 in a communicative manner. The maintenance confirmation screen on the external device is displayed on the output display device provided on the PC, etc. The maintenance confirmation screen on the external device includes an external information display unit 401, an implementation permission selection unit 402, and an implementation denial selection unit 403. The external information display unit 401 displays guidance regarding the confirmation of whether or not maintenance can be performed. For example, the external information display unit 401 displays a guidance message prompting the user to input whether or not maintenance can be performed as notification information. The external information display unit 401 may also display information indicating the status of the print job. If the output display device is configured using a touch panel, the implementation permission selection unit 402 and the implementation denial selection unit 403 display areas on the maintenance confirmation screen that the user can touch. When a user views the external information display unit 401 and wishes to permit the maintenance, they touch the implementation permission selection unit 402 to have the printing device 100 perform the maintenance. If a user views the external information display unit 401 and wishes to refuse maintenance, they can stop the maintenance on the printing device 100 by touching the refusal selection unit 403.

[0033] Furthermore, the content displayed on the panel display unit 301 is not limited to that shown in Figure 6. The content displayed on the external information display unit 401 is not limited to that shown in Figure 7. When the output display device is configured using a liquid crystal display or the like, the implementation permission selection unit 402 and the implementation denial selection unit 403 may be selected using a mouse or keyboard provided on a PC or the like.

[0034] <Control method for printing devices> Next, the control method of the printing apparatus in the first embodiment will be described with reference to Figure 8. In this embodiment, a configuration that can improve the throughput of the printing apparatus will be described. Figure 8 is a flowchart of the control method of the printing apparatus in the first embodiment. Note that each step of the flowchart shown in Figure 8 is executed by the CPU 128 executing a program stored in the FlashROM 123 of the printer controller 120 as a computer. In this embodiment, when printing of an image is completed, the CPU 128 determines whether or not to perform maintenance in parallel with the drying of the printing medium (roll paper P) based on the length of the margins between images and the drying time. During printing, the movement of the liquid ejection head 151 in the main scanning direction and the transport operation of the printing medium by the transport motor 153 are performed alternately and intermittently, so the printing medium is transported intermittently at regular intervals by the transport motor 153. In order to perform uniform drying by the fuser 154, the printing medium on which the image has been printed is transported intermittently at regular intervals by the transport motor 153 even while the ink is being fixed (dried) by the fuser 154.

[0035] In step S101, the CPU 128 of the printer controller 120 starts printing using the liquid ejection head 151. At this time, the liquid ejection head 151 moves in the main scanning direction (X direction) above the platen 211 and prints an image by ejecting ink onto the printing medium (roll paper P) on the platen 211.

[0036] In step S102, the CPU 128 starts drying the printing medium using the fuser 154. At this time, the fuser 154 dries the ink on the printing medium by applying hot air to the printing medium on which the image has been printed, thereby fixing the ink to the printing medium. In this embodiment, the current image on which the ink is being fixed after printing may be referred to as the first image. The image to be printed after the current image may be referred to as the second image.

[0037] In step S103, the CPU 128 determines whether the next print is scheduled. For example, the CPU 128 determines whether the second image is scheduled to be printed after the first image (the current image) whose ink is fixed by the fuser 154. If the next print is scheduled, i.e., if the determination in step S103 is YES, the process proceeds to the next step S104. If the next print is not scheduled, i.e., if the determination in step S103 is NO, the process ends without maintenance being performed.

[0038] In step S104, the CPU 128 obtains the length of the margin between the first image and the second image along the transport direction of the printing medium. The CPU 128 then compares the length of the margin between the first image and the second image along the transport direction of the printing medium with the transport length required to complete the maintenance of the liquid ejection head 151. The length required to complete the maintenance of the liquid ejection head 151 is the transport length (transport distance) of the printing medium transported by the transport device (transport motor 153 and transport roller 205) from the start to the completion of the maintenance. Hereinafter, the transport length of the printing medium transported from the start to the completion of the maintenance will be referred to as the maintenance transport length.

[0039] Figure 9 is an explanatory diagram comparing the length of the margin 231 between the first image 221 and the second image 222 with the maintenance transport length H. Figure 9(a) is an explanatory diagram showing the case where the length of the margin 231 between the first image 221 and the second image 222 is less than or equal to the maintenance transport length H. Figure 9(b) is an explanatory diagram showing the case where the length of the margin 231 between the first image 221 and the second image 222 is greater than the maintenance transport length H.

[0040] As shown in Figures 9(a) and 9(b), the margin 231 between the first image 221 and the second image 222 represents the portion of the printing medium (roll paper P) between the upstream end of the first image 221 in the transport direction and the downstream end of the second image 222 in the transport direction. In Figures 9(a) and 9(b), the maintenance transport length H is shown as the length of a hypothetical margin 239 that is replaced by the margin between the first image 221 and the second image 222. The transport direction of the printing medium is the direction indicated by the arrow 215 in Figures 9(a) and 9(b).

[0041] Here, let t be the time from the start to the completion of maintenance. Let fa be the transport length (feed amount) of the printing medium per pass during ink fixing (drying), and let ft be the time it takes to transport the printing medium by that transport length per pass. The maintenance transport length H is expressed by the following equation (1). H = t × (fa / ft) ... (1)

[0042] The time t from the start to the completion of maintenance, the transport length fa of the print medium per transport, and the time ft required to transport the print medium by that transport length per transport are stored in the FlashROM 123 or HDD 161. This allows the CPU 128 to calculate the maintenance transport length H using equation (1). The CPU 128 can also obtain the length of the margin 231 between the first image 221 and the second image 222 based on the print data input from the host computer 190.

[0043] As shown in Figure 9(a), if the length of the margin 231 between the first image 221 and the second image 222 is less than or equal to the maintenance transport length H, it is difficult to complete the maintenance while the portion of the first image 221 (the current image) in the print medium is drying. As shown in Figure 9(b), if the length of the margin 231 between the first image 221 and the second image 222 is greater than the maintenance transport length H, it is possible to complete the maintenance while the portion of the first image 221 in the print medium is drying.

[0044] Returning to Figure 8, if the length of the gap 231 between the first image 221 and the second image 222 is a first length greater than the maintenance transport length H, that is, if the determination in step S104 is YES, the process proceeds to the next step S105. If the length of the gap 231 between the first image 221 and the second image 222 is a second length less than or equal to the maintenance transport length H (shorter than the first length), that is, if the determination in step S104 is NO, the maintenance is not performed and the process ends.

[0045] In step S105, the CPU 128 determines whether the number of ink ejections from the liquid ejection head 151 since the last maintenance (since the completion of the last maintenance) exceeds a threshold. If the number of ink ejections from the liquid ejection head 151 since the last maintenance exceeds the threshold, i.e., if the determination in step S105 is YES, the process proceeds to the next step S106. If the number of ink ejections from the liquid ejection head 151 since the last maintenance is less than or equal to the threshold, i.e., if the determination in step S104 is NO, the process ends without performing maintenance. If the number of ink ejections from the liquid ejection head 151 since the last maintenance is less than or equal to the threshold, maintenance is not performed even if the length of the margin 231 is a first length greater than the maintenance transport length H.

[0046] The number of ink ejections from the liquid ejection head 151 is measured by a counter (not shown) provided in the CPU 128, for example. The counter measures the number of ink ejections from the liquid ejection head 151 based on the output amount of ink droplets recorded in a memory element provided in the ink tank (not shown), for example, using a method called dot counting. Alternatively, the counter may measure the number of ink ejections from the liquid ejection head 151 by estimating the amount of ink droplets consumed based on the arrangement data for each ink color using a software algorithm. In the method called dot counting, it is possible to measure the amount of ink ejected from the liquid ejection head 151 for each nozzle by multiplying the amount of ink ejected per ejection by the number of ejections. Therefore, the CPU 128 may determine whether or not the amount of ink ejected from the liquid ejection head 151 exceeds a threshold. Steps S104 and S105 may be performed in any order.

[0047] In step S106, the CPU 128 uses a display device (not shown) that constitutes the input / output device 162 to display a maintenance confirmation screen for the printing device 100. A user who views the panel display unit 301 of the maintenance confirmation screen touches the permission touch unit 302 if they wish to permit the maintenance. A user who views the panel display unit 301 touches the rejection touch unit 303 if they wish to reject the maintenance. An operation signal based on the touch operation of the permission touch unit 302 or the rejection touch unit 303 is transmitted from the input / output device 162 to the printer controller 120 (CPU 128).

[0048] In step S107, the CPU 128 determines whether or not maintenance is permitted based on the user's touch operation in the previous step S106. If the permission touch unit 302 on the maintenance confirmation screen is touched and maintenance is permitted, i.e., the determination in step S107 is YES, the process proceeds to the next step S108. If the rejection touch unit 303 on the maintenance confirmation screen is touched and maintenance is not permitted (rejected), i.e., the determination in step S107 is NO, the maintenance is not performed and the process ends. When the permission touch unit 302 is touched when the maintenance confirmation screen is displayed on the display device, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image 221 by the fixing device 154. When the rejection touch unit 303 is touched when the maintenance confirmation screen is displayed on the display device, the CPU 128 does not cause the maintenance device to perform maintenance even if the length of the margin 231 is a first length greater than the maintenance transport length H.

[0049] Then, in step S108, the CPU 128 decides to perform maintenance using the maintenance device (suction mechanism 170 and wiping mechanism 180). After printing the first image 221 using the liquid ejection head 151, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image 221 by the fixing device 154. At this time, when the liquid ejection head 151 moves to a position facing the suction mechanism 170, the suction mechanism 170 performs nozzle suction as described above. Also, when the liquid ejection head 151 moves to a position facing the wiping mechanism 180, the wiping mechanism 180 performs wiping as described above.

[0050] As described above, the throughput of the printing apparatus can be improved according to the first embodiment. Specifically, in this embodiment, when the next print is scheduled, the CPU 128 of the printer controller 120 obtains the length of the margin 231 between the first image 221 and the second image 222 along the transport direction of the printing medium. If the length of the margin 231 is a first length greater than a predetermined length, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image 221 by the fuser 154. If the length of the margin 231 is a second length shorter than the first length (less than or equal to the predetermined length), the CPU 128 does not cause the maintenance device to perform maintenance. In the first embodiment, the predetermined length is the maintenance transport length H. The first length is greater than the maintenance transport length H. As a result, maintenance of the liquid ejection head 151 can be performed while the ink in the first image 221 is being fixed by the fuser 154, and the maintenance can be completed before the start of printing of the second image 222. Therefore, interruptions to printing operations for maintenance can be minimized, and the reduction in the throughput of the printing device can be prevented. In this way, the throughput of the printing device can be improved.

[0051] In the first embodiment described above, the CPU 128 obtains the length of the margin 231 between the first image 221 and the second image 222 along the transport direction in the printing medium, but is not limited to this. Furthermore, the CPU 128 may obtain the length of the first image 221 along the transport direction in the printing medium based on print data input from the host computer 190. Thus, for example, in step S104, the CPU 128 may compare the smaller of the length of the margin 231 between the first image 221 and the second image 222 and the length of the first image 221 with the maintenance transport length H. If the smaller of the length of the margin 231 and the length of the first image 221 is a first length greater than the maintenance transport length H, maintenance may be performed in parallel with the fixing of ink by the fixing device 154. If the smaller of the length of the margin 231 and the length of the first image 221 is a second length less than or equal to the maintenance transport length H (shorter than the first length), maintenance may not be performed.

[0052] In step S105 of the first embodiment described above, the CPU 128 determines whether the amount of ink ejected from the liquid ejection head 151 exceeds a threshold, but is not limited to this. For example, in step S105, the CPU 128 may determine whether the time to perform maintenance falls within the maintenance permission time set by the user. The maintenance permission time is the time during which maintenance is permitted. If the time to perform maintenance falls within the maintenance permission time, the process may proceed to the next step S106. If the time to perform maintenance falls outside the maintenance permission time, the process may end without performing maintenance. Thus, during the time period excluding the maintenance permission time, maintenance does not need to be performed even if the length of the margin 231 between the first image 221 and the second image 222 is a first length greater than the maintenance transport length H. Furthermore, the determination process in step S105 may be omitted.

[0053] In step S106 of the first embodiment described above, the CPU 128 displays a maintenance confirmation screen for the printing device 100 using a display device that constitutes the input / output device 162, but is not limited to this. For example, the CPU 128 may display a maintenance confirmation screen for an external device (PC) using an output display device of an external device. In this case, in step S107, the CPU 128 may determine whether or not maintenance is permitted based on a touch operation of the execution permission selection unit 402 or execution denial selection unit 403 on the maintenance confirmation screen for the external device.

[0054] In the first embodiment described above, when the authorization touch unit 302 is touched, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink by the fixing device 154, but it is not limited to this. For example, if the authorization touch unit (and the rejection touch unit) is not touched within the set time elapsed after the maintenance confirmation screen is displayed, the CPU 128 does not have the maintenance device perform maintenance. If the rejection touch unit (and the authorization touch unit) is not touched within the set time elapsed, the CPU 128 may cause the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image by the fixing device 154.

[0055] <<Second Embodiment>> Next, a second embodiment will be described. Since the individual components in the second embodiment have the same configuration as those in the first embodiment described above, they will be described using the same reference numerals as those used for each component in the first embodiment. The printing apparatus according to the second embodiment is formed in the same manner as the printing apparatus 100 according to the first embodiment.

[0056] <Control method for printing devices> Next, the control method of the printing apparatus in the second embodiment will be described with reference to Figure 10. Figure 10 is a flowchart showing the control method of the printing apparatus in the second embodiment. The CPU 128 executes a program stored in the FlashROM 123 of the printer controller 120, which acts as a computer, thereby executing each step of the flowchart shown in Figure 10. In this embodiment, when printing of an image is completed, the CPU 128 determines whether or not to perform maintenance in parallel with the drying of the printing medium (roll paper P) based solely on the margins between images. Similar to the first embodiment, the printing medium on which the image has been printed is intermittently transported at regular intervals by the transport motor 153 even while the ink is being fixed (dried) by the fuser 154.

[0057] In step S201, the CPU 128 of the printer controller 120 starts printing using the liquid ejection head 151, similar to the first embodiment. In step S202, the CPU 128 starts drying the printing medium (roll paper P) using the fuser 154, similar to the first embodiment.

[0058] In step S203, the CPU 128 determines whether the next print is scheduled. For example, the CPU 128 determines whether it is scheduled to sequentially print multiple subsequent images, including a second image, after the first image (the current image) whose ink is fixed by the fuser 154. If the next print is scheduled, i.e., if the determination in step S203 is YES, the process proceeds to the next step S204. If the next print is not scheduled, i.e., if the determination in step S203 is NO, the process ends without maintenance being performed.

[0059] In step S204, the CPU 128 obtains the length of the margin between the first image and the second image along the transport direction in the printing medium. The CPU 128 obtains the length of the margin between each of the multiple subsequent images along the transport direction in the printing medium. Then, the CPU 128 compares the length of the margin between the first image and the second image along the transport direction in the printing medium with the length of the margin between each of the multiple subsequent images along the transport direction in the printing medium.

[0060] Figure 11 is an explanatory diagram comparing the length of the margin 231 between the first image 221 and the second image 222 with the lengths of the margins between multiple subsequent images. Figure 11(a) is an explanatory diagram showing the case where the length of the margin 231 between the first image 221 and the second image 222 is less than or equal to the length of the largest margin among the lengths of the margins between multiple subsequent images. Figure 11(b) is an explanatory diagram showing the case where the length of the margin 231 between the first image 221 and the second image 222 is greater than the length of the largest margin among the lengths of the margins between multiple subsequent images.

[0061] Figures 11(a) and 11(b) show the second image 222, the third image 223, and the fourth image 224 as subsequent images printed sequentially after the first image 221. Similar to the first embodiment, the transport direction of the printing medium (roll paper P) is the direction indicated by the arrow 215 in Figures 11(a) and 11(b). In the example shown in Figure 11(a), the length of the margin 231 between the first image 221 and the second image 222 along the transport direction of the printing medium is greater than the length of the margin 232 between the second image 222 and the third image 223. The length of the margin 231 between the first image 221 and the second image 222 along the transport direction of the printing medium is less than the length of the margin 233 between the third image 223 and the fourth image 224. Of the lengths of the margins between multiple subsequent images, the longest margin is the length of the margin 233 between the third image 223 and the fourth image 224.

[0062] In the example shown in Figure 11(b), the length of the margin 231 between the first image 221 and the second image 222 along the transport direction in the print medium is greater than the length of the margin 232 between the second image 222 and the third image 223. The length of the margin 231 between the first image 221 and the second image 222 along the transport direction in the print medium is greater than the length of the margin 233 between the third image 223 and the fourth image 224. Of the lengths of the margins between multiple subsequent images, the longest margin is the length of the margin 233 between the third image 223 and the fourth image 224. When the length of the margin 231 between the first image 221 and the second image 222 is greater than the longest margin among the lengths of the margins between multiple subsequent images, there is a relatively high probability that maintenance can be completed while the portion of the first image 221 in the print medium is drying.

[0063] Returning to Figure 10, if the length of the margin 231 is a first length greater than the length of the largest margin among the lengths of the margins between multiple subsequent images, that is, if the determination in step S204 is YES, the process proceeds to the next step S205. If the length of the margin 231 is a second length less than or equal to the length of the largest margin among the lengths of the margins between multiple subsequent images (shorter than the first length), that is, if the determination in step S204 is NO, the maintenance is not performed and the process ends. Such a determination is useful, for example, when it is difficult to predict the time from the start to the completion of maintenance, or when the time from the start to the completion of maintenance is very long. When the time from the start to the completion of maintenance is very long, it is likely that the length of any of the margins is smaller than the length required to complete the maintenance of the liquid discharge head 151 (maintenance transport length).

[0064] In step S205, the CPU 128 sends output data to an external device (PC) and displays the maintenance confirmation screen on the external device using the output display device (not shown) of the external device. If the user views the external information display unit 401 of the maintenance confirmation screen and wishes to authorize the maintenance, they touch the authorization selection unit 402. If the user views the external information display unit 401 and wishes to refuse the maintenance, they touch the refusal selection unit 403. Operation signals based on the touch operation of the authorization selection unit 402 or the refusal selection unit 403 are transmitted from the external device to the printing device 100 (CPU 128).

[0065] In step S206, the CPU 128 determines whether or not maintenance is permitted based on the user's touch operation in the previous step S205. If the permission selection unit 402 on the maintenance confirmation screen is touched and maintenance is permitted, i.e., the determination in step S206 is YES, the process proceeds to the next step S207. If the rejection selection unit 403 on the maintenance confirmation screen is touched and maintenance is not permitted (rejected), i.e., the determination in step S206 is NO, the maintenance is not performed and the process ends. When the permission selection unit 402 is touched when the maintenance confirmation screen is displayed on the output display device, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image 221 by the fixing device 154. When the rejection selection unit 403 is touched, the CPU 128 does not cause the maintenance device to perform maintenance even if the length of the margin 231 is a first length that is greater than the length of the largest margin among the margin lengths between multiple subsequent images.

[0066] Then, in step S207, the CPU 128 decides to perform maintenance using the maintenance device (suction mechanism 170 and wiping mechanism 180). Similar to the first embodiment, after printing the first image 221 using the liquid ejection head 151, the CPU 128 has the maintenance device perform maintenance in parallel with the fixing of the ink in the first image 221 by the fixing device 154.

[0067] As described above, the second embodiment can improve the throughput of the printing apparatus. Specifically, in this embodiment, when the next print is scheduled, the CPU 128 of the printer controller 120 obtains the length of the margin 231 between the first image 221 and the second image 222 along the transport direction of the printing medium. The CPU 128 also obtains the length of each margin between a plurality of subsequent images along the transport direction of the printing medium. If the length of the margin 231 is a first length greater than a predetermined length, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of ink in the first image 221 by the fixing device 154. If the length of the margin 231 is a second length shorter than the first length (less than or equal to the predetermined length), the CPU 128 does not cause the maintenance device to perform maintenance. In the second embodiment, the predetermined length is the length of the largest margin among the lengths of each margin between a plurality of subsequent images. The first length is greater than the length of the largest margin among the lengths of each margin between a plurality of subsequent images. This allows maintenance of the liquid ejection head 151 to be performed while the ink in the first image 221 is being fixed by the fuser unit 154, so that the maintenance can be completed as much as possible before the start of printing of the second image 222. Therefore, interruptions to the printing operation due to maintenance can be suppressed, and a decrease in the throughput of the printing device can be suppressed. In this way, the throughput of the printing device can be improved.

[0068] In the second embodiment described above, the CPU 128 obtains, but is not limited to, the length of the margin 231 between the first image 221 and the second image 222, and the length of each margin between the plurality of subsequent images. Furthermore, the CPU 128 may obtain the length of the first image 221 along the transport direction on the printing medium based on the print data input from the host computer 190. The CPU 128 may also obtain the lengths of the plurality of subsequent images, including the second image 222, along the transport direction on the printing medium based on the print data input from the host computer 190. Thus, for example, in step S204, the CPU 128 may compare the smaller of the margin length 231 between the first image 221 and the second image 222 and the length of the first image 221 with a predetermined length. If the smaller of the margin length 231 and the length of the first image 221 is a first length greater than the predetermined length, maintenance may be performed in parallel with the fixing of ink on the first image by the fixing device. Maintenance may not be performed if the smaller of the margin length 231 and the length of the first image 221 is a second length that is less than or equal to a predetermined length (shorter than the first length). In this case, the predetermined length may be the maximum of the smaller of the margin length between one subsequent image and the next subsequent image and the length of the said subsequent image in a plurality of subsequent images.

[0069] In step S205 of the second embodiment described above, the CPU 128 displays a maintenance confirmation screen on the external device (PC) using the output display device of the external device, but is not limited to this. For example, the CPU 128 may display a maintenance confirmation screen on the printing device 100 using the display device that constitutes the input / output device 162. In this case, in step S206, the CPU 128 may determine whether or not maintenance is permitted based on a touch operation of the permission touch unit 302 or the denial touch unit 303 on the maintenance confirmation screen for the printing device 100.

[0070] In the second embodiment described above, when the permission selection unit 402 is touched, the CPU 128 causes the maintenance device to perform maintenance in parallel with the fixing of the ink by the fixing device 154, but it is not limited to this. For example, if the permission selection unit (and the permission selection unit) is not touched within the set time elapsed after the maintenance confirmation screen is displayed, the CPU 128 does not have the maintenance device perform maintenance. If the permission selection unit (and the permission selection unit) is not touched within the set time elapsed, the CPU 128 may cause the maintenance device to perform maintenance in parallel with the fixing of the ink in the first image 221 by the fixing device 154.

[0071] In the second embodiment described above, similar to the first embodiment, maintenance may not be performed if the amount of ink ejected by the liquid ejection head 151 is below a threshold. During the time period excluding the permitted time for performing maintenance, maintenance may not be performed even if the length of the margin 231 is a first length greater than the length of the longest margin among the margin lengths between multiple subsequent images.

[0072] In each of the embodiments described above, when performing maintenance on the liquid ejection head 151, the suction mechanism 170 performs nozzle suction and the wiping mechanism 180 performs wiping, but the invention is not limited to this. For example, when performing maintenance on the liquid ejection head 151, the liquid ejection head 151 may perform a preliminary ejection of ink. In this case, the liquid ejection head 151 may move to a position opposite the suction mechanism 170 and eject ink toward the cap 171 of the suction mechanism 170 to perform the preliminary ejection of ink.

[0073] In each of the embodiments described above, the fixing device 154 dries the ink on the roll paper by applying hot air to the roll paper on which the image is printed, but it is not limited to this. For example, the fixing device may dry the ink on the roll paper by heating the roll paper with a heater provided below the roll paper. Also, if an ink that hardens with ultraviolet light is used, the fixing device may harden the ink on the roll paper by irradiating the roll paper on which the image is printed with ultraviolet light.

[0074] In the embodiments described above, roll paper is used as the printing medium, but the invention is not limited to this. For example, roll film or nonwoven fabric rolls may be used as the printing medium.

[0075] <<Other Embodiments>> The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0076] The disclosure of this embodiment includes configurations represented by the following examples of printing apparatus, printing apparatus control methods, and programs.

[0077] <Configuration 1> A transport device for transporting printing media, A liquid dispensing head that dispenses liquid onto a printing medium transported by the transport device to print an image, A fixing device that fixes the liquid discharged onto the printing medium by the liquid discharge head, A maintenance device for performing maintenance on the liquid discharge head, If a second image is to be printed after a first image, which has been fixed with liquid by the fixing device, a controller is provided to obtain the length of the margin between the first image and the second image along the transport direction on the printing medium. Equipped with, The printing apparatus is characterized in that, when the length of the margin is a first length, the controller causes the maintenance device to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device, and when the length of the margin is a second length shorter than the first length, the maintenance device does not perform the maintenance.

[0078] <Configuration 2> The printing apparatus according to configuration 1, wherein the first length is greater than the maintenance transport length of the printing medium transported by the transport device between the start and completion of the maintenance.

[0079] <Structure 3> During the fixing of the liquid by the fixing device, the transport device intermittently transports the printing medium. The aforementioned maintenance transport length is expressed by the following formula, for the printing apparatus according to configuration 2. H = t × (fa / ft) However, H: Maintenance transport length t: Time from the start to the completion of the aforementioned maintenance. fa: The length of each transport of the printing medium during the fixing process. ft: The time required to transport the printing medium by the aforementioned transport length per trip.

[0080] <Structure 4> If the controller is scheduled to sequentially print a plurality of subsequent images, including a second image, after the first image, it obtains the length of the margin between the first image and the second image along the transport direction in the printing medium, and the length of the margin between each of the plurality of subsequent images along the transport direction in the printing medium. The printing apparatus according to configuration 1, wherein the first length is greater than the length of the largest margin among the margin lengths between the plurality of subsequent images.

[0081] <Composition 5> The printing apparatus according to any one of configurations 1 to 4, wherein the controller prevents the maintenance device from performing the maintenance, even if the margin length is the first length, if the number of times the liquid has been dispensed from the liquid dispensing head since the last maintenance was performed is below a threshold.

[0082] <Composition 6> The printing apparatus according to any one of configurations 1 to 4, wherein the controller prevents the maintenance device from performing the maintenance during the time period excluding the permitted time for performing the maintenance, even if the margin length is the first length.

[0083] <Composition 7> The printing apparatus according to any one of configurations 1 to 6, wherein the controller obtains the length of the first image along the transport direction in the printing medium, and if the smaller of the margin length and the length of the first image is the first length, the fixing device fixes the liquid in the first image and the maintenance device performs the maintenance in parallel, and if the smaller of the lengths is the second length, the maintenance device does not perform the maintenance.

[0084] <Structure 8> If the length of the margin is greater than the first length, the controller displays a confirmation screen on the display device to confirm whether or not to perform the maintenance. The printing apparatus according to any one of configurations 1 to 7, wherein when an operation is performed to authorize the maintenance to be carried out when the confirmation screen is displayed on the display device, the maintenance device is made to carry out the maintenance in parallel with the fixing of the liquid in the first image by the fixing device.

[0085] <Composition 9> The printing apparatus according to configuration 8, wherein the controller prevents the maintenance device from performing the maintenance, even if the margin length is the first length, when an operation to refuse to perform the maintenance is performed when the confirmation screen is displayed on the display device.

[0086] <Composition 10> The printing apparatus according to configuration 8 or 9, wherein the controller prevents the maintenance device from performing the maintenance if the operation to authorize the maintenance is not performed within a set time elapsed after the confirmation screen is displayed on the display device, even if the margin length is the first length.

[0087] <Composition 11> The printing apparatus according to configuration 9, wherein if no operation to refuse the maintenance is performed within a set time elapsed after the confirmation screen is displayed on the display device, the controller causes the maintenance device to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device.

[0088] <Composition 12> The fixing device fixes the liquid by drying the liquid discharged onto the printing medium by the liquid discharge head, as described in any one of the configurations 1 to 11.

[0089] <Composition 13> The printing apparatus according to any one of configurations 1 to 12, wherein the maintenance includes a nozzle suction process for sucking liquid from the nozzle of the liquid discharge head.

[0090] <Composition 14> The printing apparatus according to any one of configurations 1 to 13, wherein the maintenance includes wiping off any liquid adhering to the surface of the liquid ejection head.

[0091] <Composition 15> A control method for a printing apparatus comprising: a transport device for transporting a printing medium; a liquid discharge head for dispensing liquid onto the printing medium transported by the transport device to print an image; a fixing device for fixing the liquid discharged onto the printing medium by the liquid discharge head; and a maintenance device for performing maintenance on the liquid discharge head, If it is planned to print a second image after a first image which has been fixed with liquid by the fixing device, the steps include obtaining the length of the margin between the first image and the second image along the transport direction in the printing medium, If the length of the margin is a first length, the maintenance device is made to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device; if the length of the margin is a second length shorter than the first length, the maintenance device is not made to perform the maintenance; A method for controlling a printing apparatus, characterized by having the following features.

[0092] <Composition 16> A program that causes a computer to execute the control method of the printing apparatus described in configuration 15. [Explanation of Symbols]

[0093] 100 Printing device 120 Printer Controllers 128 CPU 153 Conveyor motor 154 Fixing device 170 Suction mechanism 180 Wiping Mechanism 205 Conveyor Roller

Claims

1. A transport device for transporting printing media, A liquid dispensing head that dispenses liquid onto a printing medium transported by the transport device to print an image, A fixing device that fixes the liquid discharged onto the printing medium by the liquid discharge head, A maintenance device for performing maintenance on the liquid discharge head, When it is planned to print a second image after a first image has been fixed with liquid by the fixing device, a controller is provided to acquire the length of the margin between the first image and the second image along the transport direction on the printing medium. Equipped with, The printing apparatus is characterized in that, when the length of the margin is a first length, the controller causes the maintenance device to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device, and when the length of the margin is a second length shorter than the first length, the maintenance device does not perform the maintenance.

2. The printing apparatus according to claim 1, wherein the first length is greater than the maintenance transport length of the printing medium transported by the transport device between the start and completion of the maintenance.

3. During the fixing of the liquid by the fixing device, the transport device intermittently transports the printing medium. The printing apparatus according to claim 2, wherein the maintenance transport length is expressed by the following formula. H=t×(fa / ft) However, H: Maintenance transport length t: Time from the start to the completion of the aforementioned maintenance. fa: The length of each transport of the printing medium during the fixing process. ft: The time required to transport the printing medium by the aforementioned transport length per transport.

4. If the controller is scheduled to sequentially print a plurality of subsequent images, including a second image, after the first image, it obtains the length of the margin between the first image and the second image along the transport direction in the printing medium, and the length of the margin between each of the plurality of subsequent images along the transport direction in the printing medium. The printing apparatus according to claim 1, wherein the first length is greater than the length of the largest margin among the lengths of the margins between the plurality of subsequent images.

5. The printing apparatus according to claim 1, wherein the controller does not allow the maintenance device to perform the maintenance, even if the margin length is the first length, if the number of times the liquid has been dispensed from the liquid dispensing head since the last maintenance was performed is below a threshold.

6. The printing apparatus according to claim 1, wherein the controller prevents the maintenance device from performing the maintenance during a time period other than the permitted time for performing the maintenance, even if the margin length is the first length.

7. The printing apparatus according to claim 1, wherein the controller obtains the length of the first image along the transport direction in the printing medium, and if the smaller of the margin length and the length of the first image is the first length, the fixing device fixes the liquid in the first image and the maintenance device performs the maintenance in parallel, and if the smaller of the two lengths is the second length, the maintenance device does not perform the maintenance.

8. If the length of the margin is greater than the first length, the controller displays a confirmation screen on the display device to confirm whether or not to perform the maintenance. The printing apparatus according to claim 1, wherein when an operation is performed to authorize the maintenance to be carried out when the confirmation screen is displayed on the display device, the maintenance device is made to carry out the maintenance in parallel with the fixing of the liquid in the first image by the fixing device.

9. The printing apparatus according to claim 8, wherein the controller prevents the maintenance device from performing the maintenance, even if the margin length is a first length, when an operation to refuse to perform the maintenance is performed when the confirmation screen is displayed on the display device.

10. The printing apparatus according to claim 8 or 9, wherein the controller does not allow the maintenance device to perform the maintenance if the operation to permit the maintenance is not performed within a set time elapsed after the confirmation screen is displayed on the display device, even if the margin length is the first length.

11. The printing apparatus according to claim 9, wherein if no operation to refuse the maintenance is performed within a set time elapsed after the confirmation screen is displayed on the display device, the controller causes the maintenance device to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device.

12. The printing apparatus according to claim 1, wherein the fixing device fixes the liquid by drying the liquid discharged onto the printing medium by the liquid discharge head.

13. The printing apparatus according to claim 1, wherein the maintenance includes a nozzle suction process of sucking liquid from the nozzle of the liquid discharge head.

14. The printing apparatus according to claim 1, wherein the maintenance includes wiping off any liquid adhering to the surface of the liquid ejection head.

15. A control method for a printing apparatus comprising: a transport device for transporting a printing medium; a liquid discharge head for dispensing liquid onto the printing medium transported by the transport device to print an image; a fixing device for fixing the liquid discharged onto the printing medium by the liquid discharge head; and a maintenance device for performing maintenance on the liquid discharge head, If it is planned to print a second image after a first image which has been fixed with liquid by the fixing device, the steps include obtaining the length of the margin between the first image and the second image along the transport direction in the printing medium, If the length of the margin is a first length, the maintenance device is made to perform the maintenance in parallel with the fixing of the liquid in the first image by the fixing device; if the length of the margin is a second length shorter than the first length, the maintenance device is not made to perform the maintenance; A method for controlling a printing apparatus, characterized by having the following features.

16. A program for causing a computer to execute the control method of the printing apparatus described in claim 15.

Images