Liquid ejection device, control method thereof, and program

Abstract

To suppress the problem of ink that has landed on a printing medium adhering to the roller arranged downstream in a conveyance direction with respect to the head.SOLUTION: A CPU of a printer is configured to perform recording processes of ejecting an ink from multiple nozzles for multiple recording areas aligned in a conveying direction of a sheet, the recording process including x (x is a natural number greater than or equal to 2) times of recording steps S3, S4, S8 including scanning operation and executed at time intervals for each of the multiple recording areas; and a sheet discharge process (conveyance process) S11 of conveying the sheet toward a downstream roller in the conveying direction by the conveying mechanism after performing the recording process. The CPU is further configured to determine a standby time for a first scanning operation (S2), and then, determine a tentative standby time for each of second and succeeding scanning operations (S6), and determine a standby time for a current scanning operation on the basis of the tentative standby time and the standby time of the previous scanning operation (S7). Then after a standby time for an x-th scanning operation has elapsed from the end of the x-th scanning operation, the CPU performs the sheet discharge process (conveyance process) (S10: YES → S11).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid ejection device having a roller disposed on the downstream side in the conveyance direction with respect to a head, a control method thereof, and a program.

Background Art

[0002] The recording device (liquid ejection device) described in Patent Document 1 has a paper discharge driven roller (roller) disposed on the downstream side in the sub-scanning direction (conveyance direction) with respect to the head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the paper discharge driven roller is disposed on the downstream side in the conveyance direction with respect to the head, there may occur a problem that the liquid landing on the recording medium adheres to the roller (and consequently, the liquid adhering to the roller is transferred to the recording medium). In this regard, in Patent Document 1, the above problem can be suppressed to some extent by including a ratchet in which the paper discharge driven roller has a plurality of teeth on its outer periphery. However, particularly when the ejection amount of the liquid with respect to the recording medium is large, the above problem cannot be suppressed.

[0005] An object of the present invention is to provide a liquid ejection device, a control method thereof, and a program capable of suppressing the problem that the liquid landing on the recording medium adheres to a roller disposed on the downstream side in the conveyance direction with respect to the head.

Means for Solving the Problems

[0006] The liquid ejection device according to the present invention includes a head having a plurality of nozzles, a conveyance mechanism that conveys a recording medium in a conveyance direction, the conveyance mechanism having a roller disposed on the downstream side of the head in the conveyance direction, and a control unit. The control unit performs a recording process of ejecting liquid from the plurality of nozzles onto a plurality of recording regions arranged in the conveyance direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording regions. After the recording process, the control unit performs a conveyance process of conveying the recording medium in the conveyance direction toward the roller by the conveyance mechanism. Further, based on the amount of liquid ejected from the plurality of nozzles onto the recording region in the first recording step and the conveyance time of the recording medium by the conveyance mechanism from the recording region to the roller, a first determination process for determining the standby time of the first recording step is performed. Based on the amount of liquid ejected from the plurality of nozzles onto the recording region in the nth (= 2 to x) recording step and the conveyance time of the recording medium by the conveyance mechanism from the recording region to the roller, a second determination process for determining the provisional standby time of the nth recording step is performed. A third determination process is performed to determine the standby time of the nth recording step as the longer one of the provisional standby time of the nth recording step and the time obtained by subtracting the time from the end point of the (n - 1)th recording step to the end point of the nth recording step from the standby time of the (n - 1)th recording step. After the standby time of the xth recording step has elapsed from the end point of the xth recording step, the conveyance process is executed. A liquid ejection device is provided, which is characterized by the above.

[0007] The control method according to the present invention is a control method for controlling a liquid ejection device including a head having a plurality of nozzles and a conveyance mechanism for conveying a recording medium in a conveyance direction, the conveyance mechanism having a roller disposed on the downstream side in the conveyance direction with respect to the head, the control method including: a recording process of ejecting liquid from the plurality of nozzles onto a plurality of recording regions arranged in the conveyance direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording regions; a conveyance process of conveying the recording medium in the conveyance direction toward the roller by the conveyance mechanism after the recording process; further, a first determination process of determining a standby time of the first recording step based on an amount of liquid ejected from the plurality of nozzles onto the recording region in the first recording step and a conveyance time of the recording medium by the conveyance mechanism from the recording region to the roller; a second determination process of determining a provisional standby time of the nth (n = 2 to x) recording step based on an amount of liquid ejected from the plurality of nozzles onto the recording region in the nth recording step and a conveyance time of the recording medium by the conveyance mechanism from the recording region to the roller; and a third determination process of determining, as the standby time of the nth recording step, the longer one of the provisional standby time of the nth recording step and a time obtained by subtracting a time from the end point of the (n - 1)th recording step to the end point of the nth recording step from the standby time of the (n - 1)th recording step; and executing the conveyance process after the standby time of the xth recording step has elapsed from the end point of the xth recording step.

[0008] The program according to the present invention is a program for controlling a liquid ejection device including a head having a plurality of nozzles and a conveyance mechanism for conveying a recording medium in a conveyance direction, the conveyance mechanism having a roller disposed downstream of the head in the conveyance direction, and causes the liquid ejection device to perform a recording process of ejecting liquid from the plurality of nozzles onto a plurality of recording areas arranged in the conveyance direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording areas, and includes a recording unit that causes the liquid ejection device to perform the recording process, and a conveyance unit that, after the recording process, causes the conveyance mechanism to convey the recording medium in the conveyance direction toward the roller. Further, based on the amount of liquid ejected from the plurality of nozzles onto the recording area in the first recording step and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller, a first determination unit determines the standby time of the first recording step; based on the amount of liquid ejected from the plurality of nozzles onto the recording area in the n-th (= 2 to x) recording step and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller, a second determination unit determines the provisional standby time of the n-th recording step; and a third determination unit determines the longer of the provisional standby time of the n-th recording step and the time obtained by subtracting the time from the end point of the (n - 1)-th recording step to the end point of the n-th recording step from the standby time of the (n - 1)-th recording step as the standby time of the n-th recording step. After the standby time of the x-th recording step has elapsed from the end point of the x-th recording step, the conveyance unit causes the conveyance process to be executed.

Effect of the Invention

[0009] According to the present invention, for each recording step after the second time, a provisional waiting time is determined, and based on the provisional waiting time and the waiting time of the previous recording step, the waiting time of the current recording step is determined. Then, after the waiting time of the x-th recording step has elapsed from the end point of the x-th recording step, the conveyance process is executed. In this case, when each recording area reaches the roller, the liquid that has landed on each recording area is in a dried state, and the problem of the liquid that has landed on the recording medium adhering to the roller can be suppressed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0011] <First Embodiment> The printer 100 shown in FIG. 1 is a first embodiment of the "liquid ejection device" according to the present invention. The printer 100 includes a head 10 having a plurality of nozzles 11 on its lower surface, a carriage 20 that holds the head 10, a scanning mechanism 30 that moves the carriage 20 and the head 10 in the scanning direction, a platen 40 that supports the paper P from below, a conveyance mechanism 50 that conveys the paper P in the conveyance direction, and a control device 90. The paper P corresponds to the "recording medium" of the present invention. The scanning direction, the conveyance direction, and the vertical direction are orthogonal to each other.

[0012] The scanning mechanism 30 includes a pair of guides 31 and 32 that support the carriage 20, and a belt 33 that is connected to the carriage 20. The guides 31 and 32 and the belt 33 extend in the scanning direction. When a carriage motor 30m (see FIG. 3) is driven under the control of the control device 90, the belt 33 runs, and the carriage 20 and the head 10 move in the scanning direction along the guides 31 and 32.

[0013] The platen 40 is disposed below the carriage 20 and the head 10. The paper P is supported on the upper surface of the platen 40.

[0014] The conveyance mechanism 50 has an upstream roller 51 disposed on the upstream side in the conveyance direction with respect to the head 10, and a downstream roller 52 disposed on the downstream side in the conveyance direction with respect to the head 10. The downstream roller 52 corresponds to the "roller" of the present invention, and may be configured as a spur roller having a plurality of protrusions formed on its outer peripheral surface, or may be configured as a roller made of rubber or the like having no protrusions formed on its outer peripheral surface. The head 10, the carriage 20, and the platen 40 are disposed between the upstream roller 51 and the downstream roller 52 in the conveyance direction.

[0015] The upstream roller 51 and the downstream roller 52 are each composed of a set of rotating members. The set of rotating members includes an upper rotating member disposed above the conveyance path of the paper P and a lower rotating member disposed below the conveyance path of the paper P. The upper rotating member and the lower rotating member are disposed such that their circumferential surfaces are in contact with each other.

[0016] When the conveyance motor 50m (see FIG. 3) is driven under the control of the control device 90, the rotating members of the upstream roller 51 and the downstream roller 52 rotate. As the rotating members of the upstream roller 51 and the downstream roller 52 rotate while sandwiching the paper P, the paper P is conveyed in the conveyance direction.

[0017] As shown in FIG. 2, the head 10 includes a flow path unit 12 and an actuator unit 13.

[0018] A plurality of nozzles 11 (see FIG. 1) are formed on the lower surface of the flow path unit 12.

[0019] Inside the flow path unit 12, a common flow path 12a communicating with an ink tank (not shown) and individual flow paths 12b for each nozzle 11 are formed. The individual flow path 12b is a flow path that leads from the outlet of the common flow path 12a through the pressure chamber 12p to the nozzle 11. A plurality of pressure chambers 12p are open on the upper surface of the flow path unit 12.

[0020] The actuator unit 13 includes a metal diaphragm 13a disposed so as to cover the plurality of pressure chambers 12p on the upper surface of the flow path unit 12, a piezoelectric layer 13b disposed on the upper surface of the diaphragm 13a, and a plurality of individual electrodes 13c disposed so as to face each of the plurality of pressure chambers 12p on the upper surface of the piezoelectric layer 13b.

[0021] The diaphragm 13a and the plurality of individual electrodes 13c are electrically connected to the driver IC 14. The driver IC 14 maintains the potential of the diaphragm 13a at the ground potential while changing the potential of the individual electrodes 13c. Specifically, the driver IC 14 generates a drive signal based on the control signals (waveform signal FIRE and selection signal SIN) from the control device 90 and supplies the drive signal to the individual electrodes 13c via the signal line 14s. As a result, the potential of the individual electrodes 13c changes between a predetermined drive potential (VDD) and the ground potential (0V). At this time, the portion (actuator 13x) sandwiched between each individual electrode 13c and each pressure chamber 12p in the diaphragm 13a and the piezoelectric layer 13b deforms, so that the volume of the pressure chamber 12p changes, pressure is applied to the ink in the pressure chamber 12p, and the ink is ejected from the nozzle 11. The actuator 13x is provided for each individual electrode 13c (i.e., for each nozzle 11) and can deform independently according to the potential supplied to the individual electrode 13c.

[0022] As shown in FIG. 3, the control device 90 includes a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, and an ASIC (Application Specific Integrated Circuit) 94. Among these, the CPU 91 and the ASIC 94 correspond to the "control unit" of the present invention.

[0023] The ROM 92 stores programs and data for various controls by the CPU 91 and the ASIC 94. The RAM 93 temporarily stores data (such as image data) used when the CPU 91 and the ASIC 94 execute programs. The control device 90 is communicably connected to an external device (such as a personal computer) 200, and based on the data input from the external device 200 or the input unit of the printer 100 (switches and buttons provided on the outer surface of the housing of the printer 100), the CPU 91 and the ASIC 94 execute recording processing and conveyance processing.

[0024] As shown in FIG. 3, ASIC 94 includes an output circuit 94a and a transfer circuit 94b.

[0025] The output circuit 94a generates a waveform signal FIRE and a selection signal SIN, and outputs these signals to the transfer circuit 94b for each recording period. The recording period is the time required for the paper P to move relative to the head 10 by a unit distance corresponding to the resolution of the image formed on the paper P, and corresponds to one pixel.

[0026] The waveform signal FIRE is a serial signal obtained by serializing four waveform data. The four waveform data respectively correspond to the ink droplet amounts ejected from the nozzles 11 in one recording period being "zero (no ejection)", "small", "medium", and "large", and the number of pulses is different from each other.

[0027] The selection signal SIN is a serial signal including selection data for selecting one of the above four waveform data, and is generated for each actuator 13x and for each recording period based on the image data included in the recording command.

[0028] The transfer circuit 94b transfers the waveform signal FIRE and the selection signal SIN received from the output circuit 94a to the driver IC 14. The transfer circuit 94b incorporates an LVDS (Low Voltage Differential Signaling) driver corresponding to each of the above signals, and transfers each signal to the driver IC 14 as a pulsed differential signal.

[0029] In the recording process, ASIC 94 controls the driver IC 14 to generate a drive signal based on the waveform signal FIRE and the selection signal SIN for each pixel, and supplies the drive signal to the individual electrode 13c via the signal line 14s. Thereby, ASIC 94 causes ink droplets of the droplet amount selected from among four types of droplet amounts (zero, small, medium, large) to be ejected from each of the plurality of nozzles 11 toward the paper P for each pixel.

[0030] Next, referring to FIG. 4, a program executed by the CPU 91 will be described. This program is executed after the control device 90 receives a recording command from an external device 200 or the like.

[0031] Based on the recording command, the CPU 91 executes a recording process by driving the driver IC 14, the carriage motor 30m, and the conveyance motor 50m (see FIG. 3) via the ASIC 94. In the recording process, a scanning operation (recording step) of ejecting ink from a plurality of nozzles 11 onto a recording area R (see FIG. 5) of the paper P while moving the carriage 20 and the head 10 in the scanning direction and a conveyance operation of conveying the paper P by a predetermined amount in the conveyance direction are alternately performed. As a result, ink dots are formed on the paper P and an image is recorded.

[0032] The recording area R is a partial area of the paper P and is a rectangular area extending in the scanning direction corresponding to one scanning operation (recording step). In the recording process, the scanning operation (recording step) is sequentially performed for each of a plurality of recording areas R (see FIGS. 6A and 6B) arranged in the conveyance direction on the paper P. The recording process includes x (x is a natural number of 2 or more) scanning operations (recording steps) executed at time intervals for each of the plurality of recording areas R.

[0033] In FIGS. 6A and 6B, for ease of understanding, the length in the scanning direction of each recording area R occupying the entire width (length in the scanning direction) of the paper P is shown shortened, and the plurality of recording areas R are shown shifted in the scanning direction.

[0034] In the example of FIG. 6A, the recording area R(n) corresponding to the n-th (n is a natural number) scanning operation and the recording area R(n + 1) corresponding to the (n + 1)-th scanning operation do not have an overlapping portion and are adjacent to each other in the conveyance direction. In the example of FIG. 6A, one scanning operation (recording step) is performed for a unit area Q (area corresponding to a predetermined amount of the conveyance operation) of the paper P. In this case, the unit area Q coincides with the recording area R corresponding to one scanning operation.

[0035] In the example of FIG. 6B, the recording area R(n) corresponding to the n-th scanning operation and the recording area R(n + 1) corresponding to the (n + 1)-th scanning operation have an overlapping portion. In the example of FIG. 6B, three scanning operations (recording steps) are performed on the unit area Q of the sheet P. That is, the ink ejected in the n-th scanning operation, the ink ejected in the (n + 1)-th scanning operation, and the ink ejected in the (n + 2)-th scanning operation land on the unit area Q. In this case, the length of the unit area Q in the conveyance direction is 1 / 3 of the length of the recording area R in the conveyance direction corresponding to one scanning operation.

[0036] First, as shown in FIG. 4, the CPU 91 sets n = 1 (S1).

[0037] After S1, the CPU 91 determines the standby time for the n(=1)-th scanning operation (S2: first determination process). The CPU 91 stores the determined standby time in the RAM 93.

[0038] In S2, the CPU 91 determines the standby time for the n(=1)-th scanning operation based on the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the n(=1)-th scanning operation indicated by the image data included in the recording command, and the conveyance time of the sheet P by the conveyance mechanism 50 from the recording area R to the downstream roller 52 (the time required to convey the sheet P by the distance D shown in FIG. 5). The CPU 91 stores the determined standby time in the RAM 93. For example, the standby time is longer as the amount of the above ink is larger, and longer as the above conveyance time is shorter.

[0039] Also, in S2, the CPU 91 determines the standby time based on either the first reference time T1 or the second reference time T2 according to whether the recording mode indicated by the recording command is the normal speed mode or the high speed mode.

[0040] In the case of the normal speed mode, for each of the x scanning operations, while moving the head 10 in the scanning direction at the first speed V1, ink is ejected from a plurality of nozzles 11 onto the recording area R. In the case of the high speed mode, for each of the x scanning operations, while moving the head 10 in the scanning direction at the second speed V2, ink is ejected from a plurality of nozzles 11 onto the recording area R. That is, for each of the x scanning operations, while moving the head 10 in the scanning direction at the first speed V1 or the second speed V2, ink is ejected from a plurality of nozzles 11 onto the recording area R. The second speed V2 is higher than the first speed V1 (V2 > V1).

[0041] The first reference time T1 and the second reference time T2 are stored in the ROM 92 (see FIG. 3) corresponding to the "memory unit" of the present invention. The second reference time T2 is shorter than the first reference time T1 (T2 < T1). For example, the first reference time T1 may be 500 ms and the second reference time T2 may be 300 ms.

[0042] The maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the normal speed mode is larger than the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the high speed mode. That is, in the high speed mode, relatively small ink droplets are ejected.

[0043] In S2, when in the normal speed mode, the CPU 91 determines the standby time based on the first reference time T1, while when in the high speed mode, the CPU 91 determines the standby time based on the second reference time T2. For example, when other conditions except the recording mode are the same, the standby time in the normal speed mode is longer than that in the high speed mode.

[0044] After S2, the CPU 91 executes the first (n = 1) scanning operation (recording step) of ejecting ink from the nozzles 11 onto the recording area R (see FIG. 5) while moving the carriage 20 and the head 10 in the scanning direction (S3).

[0045] After S3, the CPU 91 executes a conveyance operation to convey the sheet P by a predetermined amount in the conveyance direction by the conveyance mechanism 50 (S4).

[0046] After S4, the CPU 91 sets n = n + 1 (S5).

[0047] After S5, the CPU 91 determines the provisional standby time for the n-th (= 2 to x) scanning operation (S6: second determination process). The CPU 91 stores the determined provisional standby time in the RAM 93.

[0048] In S6, the CPU 91 determines the provisional standby time for the n-th (= 2 to x) scanning operation based on the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the n-th (= 2 to x) scanning operation indicated by the image data included in the recording command, and the conveyance time of the sheet P by the conveyance mechanism 50 from the recording area R to the downstream roller 52 (the time required to convey the sheet P by the distance D shown in FIG. 5). The CPU 91 stores the determined provisional standby time in the RAM 93. For example, the provisional standby time is longer as the amount of the above ink is larger, and is longer as the above conveyance time is shorter.

[0049] Also, in S6, the CPU 91 determines the provisional standby time based on either the first reference time T1 or the second reference time T2 according to whether the recording mode indicated by the recording command is the normal speed mode or the high speed mode. The CPU 91 determines the provisional standby time based on the first reference time T1 in the case of the normal speed mode, while determines the provisional standby time based on the second reference time T2 in the case of the high speed mode. For example, when other conditions except the recording mode are the same, the provisional standby time in the normal speed mode is longer than that in the high speed mode.

[0050] After S6, the CPU 91 determines the standby time for the n-th (= 2 to x) scanning operation (S7: third determination process).

[0051] In S7, the CPU 91 determines the waiting time for the n-th scanning operation as the longer one between the provisional waiting time for the n-th scanning operation and the time obtained by subtracting the waiting time for the (n - 1)-th scanning operation from the time from the end point of the (n - 1)-th scanning operation to the end point of the n-th scanning operation. At this time, while the CPU 91 stores the longer one of the provisional waiting time for the n-th scanning operation and the time obtained by subtracting the waiting time for the (n - 1)-th scanning operation from the time from the end point of the (n - 1)-th scanning operation to the end point of the n-th scanning operation in the RAM 93, it deletes the shorter one of them from the RAM 93. Details of S7 will be described later with reference to FIG. 7.

[0052] After S7, the CPU 91 executes the n-th (= 2 to x) scanning operation (recording step) (S8).

[0053] After S8, the CPU 91 determines whether n = x (S9).

[0054] If n ≠ x (S9: NO), the CPU 91 returns the process to S4 and executes the processes after S5 again.

[0055] Here, with reference to FIG. 7, the waiting time determined for each scanning operation (recording step) will be described.

[0056] In the example of FIG. 7, the standby time of the first scanning operation is determined to be 500 ms based on, for example, the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the first scanning operation (S2). The provisional standby time of the second scanning operation is determined to be 150 ms based on, for example, the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the second scanning operation (S6). The standby time of the second scanning operation is determined to be the longer of the provisional standby time of the second scanning operation (150 ms) and the time obtained by subtracting the time from the end point of the first scanning operation to the end point of the second scanning operation (500 ms) from the standby time of the first scanning operation (500 ms) (0 ms), i.e., 150 ms (S7). The provisional standby time of the third scanning operation is determined to be 0 ms based on, for example, the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the third scanning operation (S6). The standby time of the third scanning operation is determined to be the longer of the provisional standby time of the third scanning operation (0 ms) and the time obtained by subtracting the time from the end point of the second scanning operation to the end point of the third scanning operation (500 ms) from the standby time of the second scanning operation (150 ms) (-350 ms), i.e., 0 ms (S7). The provisional standby time of the fourth scanning operation is determined to be 0 ms based on, for example, the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the fourth scanning operation (S6). The standby time of the fourth scanning operation is determined to be the longer of the provisional standby time of the fourth scanning operation (0 ms) and the time obtained by subtracting the time from the end point of the third scanning operation to the end point of the fourth scanning operation (500 ms) from the standby time of the third scanning operation (0 ms) (-500 ms), i.e., 0 ms (S7). The provisional standby time of the fifth scanning operation is determined to be 500 ms based on, for example, the amount of ink ejected from the plurality of nozzles 11 onto the recording area R in the fifth scanning operation (S6). The standby time of the fifth scanning operation is determined to be the longer of the provisional standby time of the fifth scanning operation (500 ms) and the time obtained by subtracting the time from the end point of the fourth scanning operation to the end point of the fifth scanning operation (500 ms) from the standby time of the fourth scanning operation (0 ms) (-500 ms), i.e., 500 ms (S7).

[0057] When n = x (S9: YES), the CPU 91 determines whether or not the waiting time for the x-th scanning operation has elapsed since the end of the x-th scanning operation (S10).

[0058] If it is determined that the waiting time for the x-th scanning operation has not elapsed since the end of the x-th scanning operation (S10: NO), the CPU 91 repeats the process of S10.

[0059] If it is determined that the waiting time for the x-th scanning operation has elapsed since the end of the x-th scanning operation (S10: YES), the CPU 91 executes a paper discharge process (S11) and ends the program.

[0060] In S11, the CPU 91 causes the transport mechanism 50 to transport the sheet P in the transport direction toward the downstream roller 52 with a transport amount equal to or greater than a predetermined amount of the transport operation. As a result, the recording areas R corresponding to the n-th (= 1 to x) scanning operations sequentially reach the downstream roller 52.

[0061] In the program of FIG. 4, the processes of S3 and S4, and the process of S8 → S9: NO → S4 correspond to the "recording process" of the present invention. S11 corresponds to the "transport process" of the present invention.

[0062] As described above, according to the present embodiment, for each scanning operation (recording step) after the second time, a temporary waiting time is determined (S6), and the waiting time for the current scanning operation (recording step) is determined based on the temporary waiting time and the waiting time for the previous scanning operation (recording step) (S7). Then, after the waiting time for the x-th scanning operation (recording step) has elapsed since the end of the x-th scanning operation (recording step), a paper discharge process (transport process) is executed (S10: YES → S11). In this case, when each recording area R reaches the downstream roller 52, the ink that has landed on each recording area R is in a dried state, and the problem of the ink adhering to the downstream roller 52 can be suppressed.

[0063] The reference times T1 and T2 used in the determination process (S2) of the waiting time for the first scanning operation and the determination process (S6) of the provisional waiting time for the n-th (= 2 to x) scanning operation are different between the normal speed mode and the high speed mode. Thereby, it is possible to appropriately determine a waiting time that can suppress the problem that the ink landing on the sheet P adheres to the downstream roller 52.

[0064] In the normal speed mode, the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 is larger than the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the high speed mode. The larger the maximum value is, the more time is required until the ink landing on the sheet P dries. Therefore, in the normal speed mode where the maximum value is larger, the determination process (S2) of the waiting time for the first scanning operation and the determination process (S6) of the provisional waiting time for the n-th (= 2 to x) scanning operation are performed based on the first reference time T1 (> the second reference time T2). Thereby, it is possible to more appropriately determine a waiting time that can suppress the problem that the ink landing on the sheet P adheres to the downstream roller 52.

[0065] <Second Embodiment> Subsequently, a second embodiment of the present invention will be described.

[0066] In the first embodiment, S2 and S6 are executed based on different reference times T1 and T2 between the normal speed mode and the high speed mode. On the other hand, in the second embodiment, S2 and S6 are executed based on different reference times T1 and T2 between the normal image quality mode and the high image quality mode. Note that the reference time T1 of the first embodiment and the reference time T1 of the second embodiment may be different from each other or the same as each other. The reference time T2 of the first embodiment and the reference time T2 of the second embodiment may be different from each other or the same as each other.

[0067] The first reference time T1 and the second reference time T2 are stored in the ROM 92 (see FIG. 3) corresponding to the "storage unit" of the present invention. The second reference time T2 is shorter than the first reference time T1 (T2 < T1). For example, the first reference time T1 may be 500 ms and the second reference time T2 may be 250 ms.

[0068] In S2, the CPU 91 determines the standby time based on either the first reference time T1 or the second reference time T2 according to whether the recording mode indicated by the recording instruction is the normal image quality mode or the high image quality mode. When the normal image quality mode is selected, the CPU 91 determines the standby time based on the first reference time T1, while when the high image quality mode is selected, the CPU 91 determines the standby time based on the second reference time T2. For example, when other conditions except the recording mode are the same, the standby time in the normal image quality mode is longer than that in the high image quality mode.

[0069] In S6, the CPU 91 determines the temporary standby time based on either the first reference time T1 or the second reference time T2 according to whether the recording mode indicated by the recording instruction is the normal image quality mode or the high image quality mode. When the normal image quality mode is selected, the CPU 91 determines the temporary standby time based on the first reference time T1, while when the high image quality mode is selected, the CPU 91 determines the temporary standby time based on the second reference time T2. For example, when other conditions except the recording mode are the same, the temporary standby time in the normal image quality mode is longer than that in the high image quality mode.

[0070] In the normal image quality mode, as shown in FIG. 6A, the recording process causes a (a = 1 in this embodiment) scanning operation (recording step) to be performed on the unit area Q (the area corresponding to a predetermined amount of the conveying operation) of the paper P.

[0071] In the high image quality mode, as shown in FIG. 6B, the recording process causes b (b = 3 in this embodiment) scanning operations (recording steps) to be performed on the unit area Q (the area corresponding to a predetermined amount of the conveying operation) of the paper P. a and b are natural numbers, and a < b.

[0072] The maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the normal image quality mode is larger than the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the high image quality mode. That is, in the high image quality mode, relatively small ink droplets are ejected.

[0073] In the high-quality mode, the CPU 91 selectively ejects ink from a plurality of nozzles 11 based on data obtained by decomposing image data into complementary patterns in each scanning operation.

[0074] Specifically, as shown in FIG. 8, image data indicating the amount of ink ejected for a unit area Q (an area corresponding to a predetermined amount of the conveyance operation) is decomposed into complementary patterns for partial image data of a recording area R(n) corresponding to the n-th scanning operation, partial image data of a recording area R(n + 1) corresponding to the (n + 1)-th scanning operation, and partial image data of a recording area R(n + 2) corresponding to the (n + 2)-th scanning operation.

[0075] The ejection duty for the recording area R in each scanning operation changes in three steps of 20%, 30%, and 50% from the upstream side to the downstream side in the conveyance direction. The ejection duty refers to the ratio of the ejection amount of the nozzle 11 to the required ejection amount of the nozzle 11 based on the image data included in the recording command. The ejection duty for the unit area Q is the sum of the ejection duty of 50% for the n-th scanning operation, the ejection duty of 30% for the (n + 1)-th scanning operation, and the ejection duty of 20% for the (n + 2)-th scanning operation, and totals 100%. The ejection duty of 20% for the (n + 2)-th scanning operation for the unit area Q is lower than the ejection duty of 30% for the (n + 1)-th scanning operation for the unit area Q. The ejection duty of 30% for the (n + 1)-th scanning operation for the unit area Q is lower than the ejection duty of 50% for the n-th scanning operation for the unit area Q.

[0076] As described above, according to the present embodiment, the reference times T1 and T2 used in the determination process (S2) of the standby time for the first scanning operation and the determination process (S6) of the temporary standby time for the n-th (= 2 to x) scanning operation are different between the normal-quality mode and the high-quality mode. Thereby, it is possible to appropriately determine a standby time that can suppress the problem that the ink landing on the paper P adheres to the downstream roller 52.

[0077] In the normal image quality mode, the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 is greater than the maximum value of the amount per unit area of the ink droplets ejected from one of the plurality of nozzles 11 in the high image quality mode. The larger the maximum value is, the more time it takes for the ink landing on the paper P to dry. Therefore, in the normal image quality mode where the maximum value is larger, based on the first reference time T1 (> the second reference time T2), the determination process (S2) of the waiting time for the first scanning operation and the determination process (S6) of the provisional waiting time for the n (= 2 to x) -th scanning operation are performed. Thereby, it is possible to more appropriately determine the waiting time that can suppress the problem that the ink landing on the paper P adheres to the downstream roller 52.

[0078] In the high image quality mode, the CPU 91 selectively ejects ink from the plurality of nozzles 11 based on the data obtained by decomposing the image data into complementary patterns in each scanning operation (see FIG. 8). In this case, when any one of the plurality of nozzles 11 is a defective nozzle, the image can be complemented by another nozzle corresponding to the position of the defective nozzle in a scanning operation different from the scanning operation in which the defective nozzle is used, thereby suppressing the deterioration of the image quality.

[0079] The ink ejected in the (n + 2)(α)-th scanning operation lands on the paper P later than the ink ejected in the (n + 1)(β)-th scanning operation and is less likely to dry over time. Therefore, in the present embodiment, the ejection duty 20% in the (n + 2)-th scanning operation for the unit area Q is lower than the ejection duty 30% in the (n + 1)-th scanning operation for the unit area Q (see FIG. 8). Also, the ink ejected in the (n + 1)(α)-th scanning operation lands on the paper P later than the ink ejected in the n(β)-th scanning operation and is less likely to dry over time. Therefore, in the present embodiment, the ejection duty 30% in the (n + 1)-th scanning operation for the unit area Q is lower than the ejection duty 50% in the n-th scanning operation for the unit area Q (see FIG. 8). Thereby, the ink landing on the paper P becomes easier to dry, and the problem that the ink landing on the paper P adheres to the downstream roller 52 can be more reliably suppressed.

[0080] <Embodiment 3> Next, a third embodiment of the present invention will be described.

[0081] In the first embodiment, S2 and S6 are executed based on different reference times T1 and T2 in the normal speed mode and the high speed mode. On the other hand, in the third embodiment, S2 and S6 are executed based on different reference times T1 and T2 according to the type of the sheet P. Note that the reference time T1 in the first embodiment and the reference time T1 in the third embodiment may be different from each other or the same as each other. The reference time T2 in the first embodiment and the reference time T2 in the third embodiment may be different from each other or the same as each other.

[0082] The first reference time T1 and the second reference time are stored in the ROM92 (see FIG. 3) corresponding to the "memory unit" of the present invention. Generally, for glossy paper, the ink penetration speed is lower than that of plain paper, and it takes time until the ink landing on the sheet P dries. Therefore, the first reference time T1 is longer than the second reference time T2. In other words, the second reference time T2 is shorter than the first reference time T1 (T2 < T1). For example, the first reference time T1 may be 500 ms and the second reference time T2 may be 200 ms.

[0083] In S2, the CPU91 determines the standby time based on either the first reference time T1 or the second reference time T2 according to whether the type of the sheet P indicated by the recording command is glossy paper (first type) or plain paper (second type). When the sheet P is glossy paper, the CPU91 determines the standby time based on the first reference time T1, while when the sheet P is plain paper, the CPU91 determines the standby time based on the second reference time T2. For example, when other conditions except the type of the sheet P are the same, the standby time in the case of glossy paper is longer than that in the case of plain paper.

[0084] In S6, the CPU 91 determines the temporary standby time based on either the first reference time T1 or the second reference time T2 according to whether the type of the paper P indicated by the recording instruction is glossy paper (first type) or plain paper (second type). When the paper is glossy paper, the CPU 91 determines the temporary standby time based on the first reference time T1, while when the paper is plain paper, the CPU 91 determines the temporary standby time based on the second reference time T2. For example, when other conditions except the type of the paper P are the same, the temporary standby time is longer for glossy paper than for plain paper.

[0085] As described above, according to the present embodiment, the reference times T1 and T2 used in the determination process (S2) of the standby time for the first scanning operation and the determination process (S6) of the temporary standby time for the n-th (= 2 to x) scanning operation are different according to the type of the paper P (the difference in the ink penetration speed). Thereby, it is possible to appropriately determine a standby time that can suppress the problem that the ink landing on the paper P adheres to the downstream roller 52.

[0086] <Modification Example> As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various design changes are possible as long as they are described in the claims.

[0087] For example, in the above-described embodiment, as the distance from the recording area to the roller, the center distance between the recording area and the roller (refer to the distance D in FIG. 5) is exemplified, but it is not limited thereto. For example, the distance from the upstream end in the conveyance direction of the recording area to the upstream end in the conveyance direction of the roller, the distance from the downstream end in the conveyance direction of the recording area to the downstream end in the conveyance direction of the roller, the distance from the downstream end in the conveyance direction of the recording area to the upstream end in the conveyance direction of the roller, the distance from the upstream end in the conveyance direction of the recording area to the downstream end in the conveyance direction of the roller, etc. may be used as the distance from the recording area to the roller.

[0088] When there are a plurality of rollers on the downstream side in the conveyance direction with respect to the head, any roller for which it is desired to suppress the problem that the liquid landing on the recording medium adheres to can be used as the "roller" of the present invention.

[0089] As factors for determining the standby time and the temporary standby time, the color of the liquid, the components of the liquid, the environmental temperature, the environmental humidity, etc. may be added.

[0090] In each determination process, a weight corresponding to the position in the scanning direction may be assigned to the amount of liquid with respect to the recording area. For example, when a plurality of partial rollers constituting the roller of the present invention are arranged at intervals in the scanning direction, a larger weight may be assigned to the position where each partial roller is provided in the scanning direction than to other positions.

[0091] The program in FIG. 4 is based on the premise that the recording area corresponding to the first scanning operation (recording step) does not reach the downstream roller 52 at the end of the x-th scanning operation (recording step). If, before the end of the x-th scanning operation (recording step), the recording area corresponding to the first scanning operation (recording step) reaches the downstream roller 52, the paper discharge process (conveying process) may be executed after the standby time of the scanning operation (recording step) has elapsed from the end of the scanning operation (recording step) immediately before the recording area corresponding to the first scanning operation (recording step) reaches the downstream roller 52.

[0092] In the high-quality mode, it is not limited to the fact that three scanning operations (recording steps) are performed on the unit area Q of the paper P (see FIG. 6B), and any number of scanning operations (recording steps) of two or more may be performed.

[0093] The head is serial in the above-described embodiment, but may be line type.

[0094] The liquid ejected from the nozzle is not limited to ink, and may be a liquid other than ink (for example, a processing liquid that aggregates or precipitates components in the ink, etc.).

[0095] The recording medium is not limited to paper, and may be, for example, cloth, a resin member, etc.

[0096] The program according to the present invention can be recorded and distributed on a removable recording medium such as a flexible disk or a fixed recording medium such as a hard disk, and can also be distributed via a communication line.

[0097] The present invention is not limited to printers, and is also applicable to facsimiles, copiers, multifunction devices, etc. Further, the present invention is also applicable to a liquid ejection device used for applications other than image recording (for example, a liquid ejection device that ejects a conductive liquid onto a substrate to form a conductive pattern).

Explanation of Signs

[0098] 10 Head 11 Nozzle 50 Conveying mechanism 52 Downstream roller (roller) 91 CPU (Control unit) 92 ROM (Storage unit) 94 ASIC (Control unit) 100 Printer (Liquid ejection device) P Paper (Recording medium) Q Unit area R Recording area

Claims

1. a head having a plurality of nozzles; a transport mechanism for transporting a recording medium in a transport direction, the transport mechanism having a roller disposed downstream of the head in the transport direction; a control unit, wherein the control unit performs a recording process of discharging liquid from the plurality of nozzles onto a plurality of recording areas arranged in the transport direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording areas; after the recording process, performs a transport process of transporting the recording medium in the transport direction toward the roller by the transport mechanism; furthermore, a first determination process for determining a standby time of the first recording step based on an amount of liquid discharged from the plurality of nozzles onto the recording area in the first recording step and a transport time of the recording medium by the transport mechanism from the recording area to the roller; a second determination process for determining a provisional standby time of the nth (n = 2 to x) recording step based on an amount of liquid discharged from the plurality of nozzles onto the recording area in the nth recording step and a transport time of the recording medium by the transport mechanism from the recording area to the roller; a third determination process for determining, as the standby time of the nth recording step, the longer one of the provisional standby time of the nth recording step and a time obtained by subtracting, from the standby time of the (n - 1)th recording step, a time from the end point of the (n - 1)th recording step to the end point of the nth recording step; and performs the transport process after the standby time of the xth recording step has elapsed from the end point of the xth recording step. A liquid ejection device characterized by this.

2. each of the plurality of recording steps causes the head to perform a scanning operation of discharging liquid from the plurality of nozzles onto the recording area while moving the head in a scanning direction intersecting the transport direction at a first speed or a second speed higher than the first speed; further includes a storage unit that stores a first reference time and a second reference time shorter than the first reference time; wherein the control unit When causing the scanning operation to be performed at the first speed in each of the plurality of recording steps, in the first determination process, the standby time of the first recording step is determined based on the first reference time, and in the second determination process, the provisional standby time of the nth recording step is determined based on the first reference time. The liquid ejection apparatus according to claim 1, wherein when causing the scanning operation to be performed at the second speed in each of the plurality of recording steps, in the first determination process, the standby time of the first recording step is determined based on the second reference time, and in the second determination process, the provisional standby time of the nth recording step is determined based on the second reference time.

3. The maximum value of the amount per unit area of droplets ejected from one of the plurality of nozzles when causing the scanning operation to be performed at the first speed in each of the plurality of recording steps is larger than the maximum value of the amount per unit area of droplets ejected from one of the plurality of nozzles when causing the scanning operation to be performed at the second speed in each of the plurality of recording steps. The liquid ejection apparatus according to claim 2.

4. The recording process causes the recording steps to be performed a or b times (a and b are natural numbers, a < b) on a unit area of the recording medium. Further comprising a storage unit. The storage unit stores a first reference time and a second reference time shorter than the first reference time. The control unit. When the recording process causes the recording steps to be performed a times on the unit area, in the first determination process, the standby time of the first recording step is determined based on the first reference time, and in the second determination process, the provisional standby time of the nth recording step is determined based on the first reference time. The liquid ejection apparatus according to claim 1, wherein when the recording process causes the recording steps to be performed b times on the unit area, in the first determination process, the standby time of the first recording step is determined based on the second reference time, and in the second determination process, the provisional standby time of the nth recording step is determined based on the second reference time.

5. When the recording process causes the a recording steps to be performed on the unit area, the maximum value of the amount per unit area of the liquid droplets ejected from one of the plurality of nozzles is greater than the maximum value of the amount per unit area of the liquid droplets ejected from one of the plurality of nozzles when the recording process causes the b recording steps to be performed on the unit area. The liquid ejection apparatus according to claim 4, characterized in that.

6. The control unit, When the recording process causes a plurality of recording steps to be performed on the unit area, the liquid is selectively ejected from the plurality of nozzles based on data obtained by decomposing the image data into complementary patterns in each recording step. The liquid ejection apparatus according to claim 4, characterized in that.

7. When the recording process causes a plurality of recording steps to be performed on the unit area, the ejection duty in the α-th recording step for the unit area is lower than the ejection duty in the β-th (<α) recording step for the unit area. The liquid ejection apparatus according to claim 6, characterized in that.

8. Further comprising a storage unit, The storage unit stores a first reference time and a second reference time shorter than the first reference time, The control unit, When the recording medium is of the first type, the standby time is determined in the first determination process and the temporary standby time is determined in the second determination process based on the first reference time. When the recording medium is of the second type having a higher liquid penetration rate than the first type, the standby time is determined in the first determination process and the temporary standby time is determined in the second determination process based on the second reference time. The liquid ejection apparatus according to claim 1, characterized in that.

9. A control method for controlling a liquid ejection apparatus including a head having a plurality of nozzles and a transport mechanism for transporting a recording medium in a transport direction, the transport mechanism having a roller disposed downstream of the head in the transport direction. A recording process of ejecting liquid from the plurality of nozzles onto a plurality of recording areas arranged in the transport direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording areas. After the recording process, a transport process of transporting the recording medium in the transport direction toward the roller by the transport mechanism is executed. Furthermore, A first determination process for determining a standby time of the first recording step based on the amount of liquid ejected from the plurality of nozzles onto the recording area and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller in the first recording step; A second determination process for determining a provisional standby time of the n-th recording step based on the amount of liquid ejected from the plurality of nozzles onto the recording area and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller in the n-th recording step (n = 2 to x); A third determination process for determining, as the standby time of the n-th recording step, the longer one of the provisional standby time of the n-th recording step and the time obtained by subtracting the time from the end point of the (n - 1)-th recording step to the end point of the n-th recording step from the standby time of the (n - 1)-th recording step; and execute A control method, characterized in that after the standby time of the x-th recording step has elapsed from the end point of the x-th recording step, the conveyance process is executed.

10. A program for controlling a liquid ejection device including a head having a plurality of nozzles and a conveyance mechanism for conveying a recording medium in a conveyance direction, the conveyance mechanism having a roller disposed downstream of the head in the conveyance direction, The liquid ejection device is A recording means for causing the liquid ejection device to execute a recording process of ejecting liquid from the plurality of nozzles onto the plurality of recording areas arranged in the conveyance direction on the recording medium, the recording process including x (x is a natural number of 2 or more) recording steps executed at time intervals for each of the plurality of recording areas, and A conveyance means for causing the conveyance mechanism to execute a conveyance process of conveying the recording medium in the conveyance direction toward the roller after the recording process, Furthermore, A first determination means for determining a standby time of the first recording step based on the amount of liquid ejected from the plurality of nozzles onto the recording area and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller in the first recording step; Second determination means for determining a provisional standby time for the n-th recording step based on the amount of liquid ejected from the plurality of nozzles onto the recording area and the conveyance time of the recording medium by the conveyance mechanism from the recording area to the roller in the n-th (= 2 to x) recording step, and Function as third determination means for determining, as the standby time for the n-th recording step, the longer of the provisional standby time for the n-th recording step and the time obtained by subtracting the standby time for the (n - 1)-th recording step from the time from the end point of the (n - 1)-th recording step to the end point of the n-th recording step, A program, characterized in that after the standby time for the x-th recording step has elapsed from the end point of the x-th recording step, the conveyance means is caused to execute the conveyance process.

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