Inkjet recording apparatus, control method, and program

Abstract

To shorten time elapsed until an ink circulation unit becomes in a state in which ink can be discharged without density unevenness after returning from a pause state while reducing operation time of the ink circulation unit.SOLUTION: An ink circulation type ink jet recording apparatus acquires a return time which is a time at which the ink jet recording apparatus returns from a first state being a state in which a recording operation is suspended to a second state being a state in which the recording operation can be executed, and control means executes maintenance before return including ink circulation by circulation means for returning the ink jet recording apparatus to the second state after the ink jet recording apparatus transitions to the first state, and completes the maintenance before return before the acquired return time.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to the suspension and restoration of ink circulation in an ink circulation type inkjet recording apparatus.

Background Art

[0002] Inkjet technology is required to be widely developed for industrial applications. For example, there is ink in which coloring materials such as white pigments such as titanium oxide, metallic pigments such as aluminum, and disperse dyes for textiles are dispersed. Since these coloring materials tend to settle, if concentration unevenness of the coloring materials occurs in the ink, a desired image may not be obtained. Therefore, it is necessary to reduce the concentration unevenness by circulating the ink or stirring the ink in the tank before starting the recording.

[0003] However, when starting the preparation operation including ink circulation and stirring after starting up the apparatus, it takes time until the ink can be ejected without concentration unevenness, and there is a problem that productivity decreases. On the other hand, if the ink circulation and stirring are continued even during the standby period when the apparatus is not performing the recording operation, the consumption of the circulation pump is accelerated, and there is a problem that productivity decreases due to the downtime caused by pump replacement.

[0004] Regarding the ink circulation during the standby period, in Patent Document 1, intermittent circulation in which the ink is circulated at predetermined time intervals during the non-operating period of the inkjet recording apparatus has been proposed. In addition, it has been proposed to start the ink circulation as a preliminary operation when there is a main power supply ON or a command for apparatus operation during the non-operating period. By performing such intermittent ink circulation and ink circulation at the time of restoration, a reduction in the operating time of the pump is expected as compared with the case where the ink circulation is always continued during the standby period.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the procedure disclosed in Patent Document 1, ink circulation is started when the user gives an instruction to turn on the main power or operate the apparatus. Therefore, there is a waiting time until the ink reaches a state where it can be ejected without density unevenness, and there is still room for improvement. An object of the present disclosure is to reduce the operation time of ink circulation and shorten the waiting time of the user until the ink reaches a state where it can be ejected without density unevenness after returning from the standby state.

Means for Solving the Problems

[0007] The inkjet recording apparatus of the present disclosure includes a recording head that performs a recording operation of ejecting ink to record an image, a circulation unit that supplies ink from a tank to the recording head and returns the ink recovered from the recording head to the tank for circulation, a control unit that controls the recording operation by the recording head and the ink circulation by the circulation unit, and an acquisition unit that acquires a return time which is a time when the inkjet recording apparatus returns from a first state where the recording operation is paused to a second state where the recording operation is executable. The control unit executes pre-return maintenance including ink circulation by the circulation unit for returning the inkjet recording apparatus to the second state after the inkjet recording apparatus has shifted to the first state, and completes the pre-return maintenance before the return time acquired by the acquisition unit.

Effects of the Invention

[0008] According to the inkjet recording apparatus of the present disclosure, it is possible to reduce the operation time of ink circulation and shorten the time until the ink reaches a state where it can be ejected without density unevenness after returning from the standby state.

Brief Description of the Drawings

[0009]

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Modes for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples, and the present disclosure is not limited to the illustrated configurations. Also, the physical property values shown in this specification are values at normal temperature (25°C) unless otherwise specified.

[0011] <First Embodiment> FIG. 1 is a diagram schematically showing the hardware configuration of an inkjet recording apparatus (hereinafter, recording apparatus 100). The recording apparatus 100 includes a recording head 101, a tank 102, a drying unit 103, and a conveyance unit 105. The conveyance unit 105 conveys a recording medium (hereinafter, referred to as sheet P) along a conveyance path. The arrow A in the figure indicates the conveyance direction of the sheet P. In the figure, X is the horizontal direction, Y is the vertical direction, and Z is the direction orthogonal to the X and Y directions.

[0012] The sheet P includes not only paper used in general recording apparatuses, but also widely, vinyl, cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc., including those capable of receiving ink. Also, the sheet may be a continuous sheet continuous in the longitudinal direction. Further, the sheet may be a label sheet to which a plurality of labels are detachably attached.

[0013] In the conveyance path of the sheet P, the sheet P passes through a position facing the ink ejection port of the recording head 101 and the drying unit 103. The conveyance unit 105 includes conveyance rollers, auxiliary rollers, a belt, etc., and is driven by a conveyance motor. The conveyance motor is driven by a control signal from the control unit 500. While being conveyed by the conveyance unit 105, recording by the recording head 101 and drying by the drying unit 103 are performed on the sheet P, and then it is discharged from the paper ejection port. The drying unit 103 is composed of, for example, a hot air dryer.

[0014] The recording head 101 is provided respectively for each type (color) of ink, such as white (W), cyan (C), magenta (M), yellow (Y), black (K), etc. A tank 102 for storing ink is connected to the recording head 101 for each type (color) of ink. The recording head 101 is provided with a plurality of ink ejection ports so as to face the recording surface of the sheet P. The recording apparatus 100 records an image by ejecting ink from the recording head 101 onto the sheet P. The ink ejection from the recording head 101 is controlled by the control unit 500 via the head driver 518. The head driver 518 executes the recording operation by the recording head 101 in conjunction with the conveyance operation of the sheet P and performs the recording process.

[0015] If there is ink with increased viscosity due to drying or foreign matter in the ink ejection port (nozzle), ejection defects such as non-ejection where the ink is not ejected may occur due to the influence. Also, the ink may cause density unevenness due to sedimentation in the recording head 101, the tank 102, and the flow paths described later. In particular, white (such as titanium oxide) and metallic (such as aluminum) which often use color materials with high specific gravity tend to have density unevenness easily.

[0016] In order to reduce such ejection defects and density unevenness, the recording apparatus 100 according to the present embodiment has an ink circulation unit 200 and an ink stirring unit 220 as shown in FIG. 2.

[0017] FIG. 2 is a diagram including the ink circulation unit 200 and the ink stirring unit 220 employed in the recording apparatus 100 of the present embodiment. Although the flow path configuration for one type of ink is shown in FIG. 2, actually, the same configuration is provided for each type of ink. Also, the ink stirring unit 220 does not necessarily need to be provided for all types of ink, and it may be configured to be provided only for white ink or metallic ink which often use color materials with high specific gravity. The operation of the ink circulation unit 200 is controlled by the control unit 500 (FIG. 5). Hereinafter, the configuration of each part of the ink circulation unit 200 will be described.

[0018] The ink circulation unit 200 includes a supply channel 201 that supplies ink from the tank 102 to the recording head 101 and a recovery channel 202 that recovers the ink not ejected from the recording head 101 and returns it to the tank 102. Pumps and valves are arranged in the middle of each of the channels 201 and 202, and the ink is circulated by operating the pumps. The channels may include a filtration filter, a degassing filter, etc. in their paths.

[0019] The ink mainly circulates through a channel intervening between the tank 102, which is mainly a liquid container, and the recording head 101. In the recording head 101, an ink ejection operation is performed based on image data, and the ink not ejected is recovered again into the tank 102. The tank 102 that stores a predetermined amount of ink is connected to a supply channel 201 for supplying ink to the recording head 101 and a recovery channel 202 for recovering ink from the recording head 101.

[0020] In addition to the supply channel 201 and the recovery channel 202, the recording and circulation path may include a relief channel 210 for stabilizing the pressure inside the circulation channel.

[0021] The supply channel 201 is a channel for supplying ink from the tank 102 to the recording head 101, and a supply pump 203 and a supply valve 204 are arranged in the middle thereof. During ink circulation, the supply pump 203 is driven with the supply valve 204 open. Thereby, while supplying ink to the recording head 101, the ink can be circulated in the circulation path. The amount of ink ejected per unit time by the recording head 101 varies according to the image data. The flow rate of the supply pump 203 is preferably determined so as to be able to cope even when the recording head 101 performs an ejection operation in which the ink consumption per unit time is maximum.

[0022] The recovery channel 202 is a channel for recovering ink from the recording head 101 to the tank 102. A recovery pump 207 is arranged in the middle of the recovery channel 202. When circulating the ink in the circulation path, the recovery pump 207 serves as a negative pressure generation source to suck the ink from the recording head 101. By driving the recovery pump 207, an appropriate pressure difference is generated between the two channels (IN channel 304 and OUT channel 305; Figure 3) in the recording head 101, and the ink can be circulated between the IN channel 304 and the OUT channel 305.

[0023] The supply channel 201 and the recovery channel 202 may each be provided with an atmosphere communication valve. By opening the atmosphere communication valves 205 and 206, the pressure difference generated in the circulation path can be eliminated.

[0024] A relief valve 211, which is a constant pressure valve, is arranged in the middle of the relief channel 210. The relief valve 211 opens and closes according to the pressure acting on itself. When the relief valve 211 opens, a channel including the relief channel 210 is formed, the ink supply amount to the recording head 101 can be adjusted, and the pressure in the circulation channel can be stabilized.

[0025] An ink stirring unit 220 is provided inside the tank 102. The ink stirring unit 220 stirs the ink in the tank 102 to reduce the density unevenness due to sedimentation. The ink stirring unit 220 is composed of, for example, a propeller-shaped stirrer 212 arranged near the bottom inside the tank 102, a shaft 213, a motor (not shown), etc. The stirrer 212 rotates by motor drive from outside the tank 102 through the shaft 213.

[0026] Note that the ink stirring unit 220 is not limited to this example. Additionally, a stirring unit using a magnetic stirrer that places a magnetic stirrer in the ink and rotates the stirrer by magnetic force from outside the tank 102 to stir the ink, or a stirring unit that swings the entire tank 102 containing the ink to stir the ink inside can also be used.

[0027] The tank 102 may be provided with a sub-tank in addition to the main tank. The sub-tank stores the ink supplied to the main tank. When there are a plurality of tanks 102 such as the main tank and the sub-tank, an ink stirring unit 220 may be provided for each tank. The operation of the motor, stirrer, etc. of the ink stirring unit 220 is controlled according to a control signal from the control unit 500.

[0028] The tank 102 may be provided with an ink remaining amount sensor (not shown) for detecting the height of the ink liquid surface. The ink remaining amount sensor is composed of, for example, a plurality of electrode pins. The control unit 500 can obtain the height of the ink liquid surface, that is, the remaining amount of ink in the tank 102, by detecting the presence or absence of a conduction current between these plurality of pins.

[0029] Next, the flow path configuration in the recording head 101 will be described. FIG. 3 is a diagram schematically showing the flow path configuration in the recording head 101. As shown in FIG. 3, inside the recording head 101, a filter 300, a first negative pressure control unit 301, a second negative pressure control unit 302, a common supply flow path (IN flow path) 304, individual supply flow paths, individual recovery flow paths, and a common recovery flow path (OUT flow path) 305 are provided. FIG. 4(a) is an enlarged plan schematic view of a part of the recording element substrate 306, and FIG. 4(b) is a cross-sectional schematic view taken along the cross-section line IVb-IVb of FIG. 4(a).

[0030] The ink supplied from the supply flow path 201 outside the recording head 101 into the recording head 101 passes through the filter 300 and is then supplied to the first negative pressure control unit 301 and the second negative pressure control unit 302. The first negative pressure control unit 301 has a control pressure set to a relatively weak negative pressure of, for example, -90 mmAq (1 mmAq = 9.80665 Pa) (a negative pressure with a small pressure difference from the atmospheric pressure).

[0031] The second negative pressure control unit 302 has a control pressure set, for example, to a strong negative pressure of -180 mmAq (a negative pressure with a large pressure difference from atmospheric pressure). The pressures in the first negative pressure control unit 301 and the second negative pressure control unit 302 are generated within an appropriate range by driving an ink circulation unit such as the recovery pump 207.

[0032] In the ink ejection unit 303, a plurality of recording element substrates 306 having a plurality of ejection ports arranged therein are arranged, and an ejection port row is formed in the Z direction in the figure. A common supply channel 304 (IN channel) for guiding the ink supplied from the first negative pressure control unit 301 and a common recovery channel 305 (OUT channel) for guiding the ink supplied from the second negative pressure control unit 302 also extend in the arrangement direction of the recording element substrates 306.

[0033] The recording element substrate 306 is provided with a pressure chamber 401 filled with ink and an ejection port 402 for ejecting the ink. In the pressure chamber 401, a recording element 403 is provided at a position facing the ejection port 402.

[0034] Further, on the recording element substrate 306, a plurality of individual supply channels 404 connected to the common supply channel 304 (IN channel) and a plurality of individual recovery channels 405 connected to the common recovery channel 305 (OUT channel) are formed for each ejection port 402. For this reason, in each recording element substrate 306, an ink flow is generated such that the ink flows in from the common supply channel 304 (IN channel) with relatively weak negative pressure and flows out to the common recovery channel 305 (OUT channel) with relatively strong negative pressure. An ink flow also occurs in the ejection ports and pressure chambers where recording is not being performed. When the ejection operation is performed on the recording element substrate 306, a part of the ink that moves from the common supply channel 304 (IN channel) to the common recovery channel 305 (OUT channel) is consumed by being ejected from the ejection port 402. The ink that is not ejected moves through the common recovery channel 305 to the recovery channel 202 outside the recording head 101.

[0035] With the above-described configuration, in the recording element substrate 306, ink flows in from the common supply channel 304 where the negative pressure is relatively weak (the absolute value of the pressure is high), and a flow is generated that flows out to the common recovery channel 305 where the negative pressure is relatively strong (the absolute value of the pressure is low).

[0036] Based on the above configuration, the control unit 500 closes the atmosphere communication valves 205 and 206, opens the supply valve 204, and drives the supply pump 203 and the recovery pump 207. Thereby, a circulation path of tank 102 → supply channel 201 → recording head 101 → recovery channel 202 → tank 102 is established. Also, during the pause period, the control unit 500 stops the supply pump 203 and the recovery pump 207 and closes the supply valve 204. As a result, the flow of ink in the recording head 101 stops.

[0037] By ink circulation, the ejection state of the ink in the recording head 101 can be restored. For example, when ink ejection failure occurs due to thickening of the ink near the ejection port 402 caused by evaporation of moisture in the ink, the ink ejection state can be restored to a normal state.

[0038] Also, in inks that are likely to have uneven density due to sedimentation, ink ejection failure may occur due to coloring materials or the like deposited near the ejection port 402, or color unevenness may occur in the image. In such cases as well, it is possible to reduce the density unevenness by ink circulation, restore the ink ejection state to a normal state, and restore the color unevenness of the image. Therefore, ink circulation is one of the recovery operations for maintaining not only the ink ejection state in the recording head 101 but also the uniformity of the image well.

[0039] The ink circulation by the above-described ink circulation unit 200 is executed not only when the recording apparatus 100 is in a state where the recording operation is possible but also when the recording operation is paused, in the pre-return maintenance, the first intermittent maintenance, and the second intermittent maintenance described later. Further, for specific inks such as white ink, metallic ink, and inks in which color materials such as disperse dyes for textiles are dispersed, which are color materials that tend to settle, it is preferable to agitate the ink in the tank 102 by the ink agitation unit 220 simultaneously with or prior to the ink circulation. In particular, by agitating near the bottom of the tank 102, the settled color materials can be homogenized. For general color inks (CMYK), ink agitation may also be performed simultaneously with or prior to the ink circulation. Note that the agitation of color inks is not essential.

[0040] Also, in addition to the pre-planned maintenance such as pre-return maintenance, first intermittent maintenance, and second intermittent maintenance, when a recording instruction is manually input, ink circulation and ink agitation are also performed. The control unit 500 controls the ink circulation unit 200 to execute ink circulation at a predetermined timing. Further, the control unit 500 controls the ink agitation unit 220 to control ink agitation at a predetermined timing. The start timing and execution time of ink circulation and ink agitation are determined by the process (Fig. 6) described later that the control unit 500 executes.

[0041] Next, the control configuration of the recording apparatus 100 according to the present embodiment will be described. Fig. 5 is a block diagram showing the control configuration of the recording apparatus 100. The recording apparatus 100 includes a control unit 500, an image processing controller 507, an operation panel 506, a sensor 519, etc. The recording apparatus 100 also has drive circuits 511 to 517 for driving a head driver 518 that drives the recording head 101, motors, actuators, pumps, etc. included in each unit of the recording apparatus 100. The head driver 518 and the drive circuits 511 to 517 are connected to the control unit 500.

[0042] The control unit (print controller) 500 includes a CPU 501, a ROM 502, a RAM 503, a storage device 504, an I / F 505, etc. The ROM 502, the RAM 503, the storage device 504, and the I / F 505 are connected to the CPU 501 via a bus 508. The CPU 501 is a processor that comprehensively controls each part of the recording device 100.

[0043] The CPU 501 calls and executes a program stored in the ROM 502 or the storage device 504, etc. into the work area of the RAM 503. The ROM 502 is a memory that permanently holds programs such as a boot program and BIOS, data, etc. The RAM 503 is a volatile or non-volatile memory that temporarily holds programs loaded from the storage device 504, the ROM 502, etc., and has a work area used for the control unit 500 to perform various processes described later.

[0044] The storage device 504 is a storage device such as an HDD, an SSD, a flash memory, etc., and holds programs executed by the CPU 501, data necessary for program execution, various parameters, setting information, job data, etc.

[0045] The program includes a program for causing the CPU 501 to execute the processing according to the method of the present disclosure. The CPU 501 realizes each means (function) of the present disclosure by executing the processing described later according to the program. The functions will be described later.

[0046] The I / F 505 includes interfaces such as USB and LAN. The control unit 500 is communicatively connected to the host device 530 via the I / F 505.

[0047] In addition, the control unit 500 is connected to the operation panel 506, the head driver 518, the sensor 519, etc. via the I / F 505. Drive circuits 511 to 517 for driving the conveyance unit 105, the head carriage unit 521, the drying unit 103, the maintenance unit 520, the ink circulation unit 200, and the ink agitation unit 220 are connected to the control unit 500 via the I / F 505. The maintenance unit 520 is a configuration related to the maintenance of the recording head 101 and includes, for example, a cap suction unit 522, a wipe unit 523, etc.

[0048] The CPU 501 controls each unit connected to the control unit 500 according to programs and various parameters stored in the ROM 502 or the storage device 504. When receiving various commands, image data, setting information input by the user, etc. from the host device 530 via the I / F 505, the CPU 501 temporarily stores them in the RAM 502.

[0049] The recording apparatus 100 of the present embodiment is provided with a pause period for pausing the ink circulation. The pause time, which is the length of the pause period, or the return time, which is the time to return after the pause period ends, is a value set by the user using a return timer described later. The setting information of the return timer transmitted from the host device 530 includes the return time or the pause time. The specific setting method of the return time or the pause time will be described later.

[0050] The image processing controller 507 is hardware capable of executing image processing faster than the CPU 501. The image processing controller 507 is activated when the CPU 501 writes parameters and data necessary for image processing to a predetermined address in the RAM 503. After reading the above parameters and data, it executes predetermined image processing on the above data. However, the image processing controller 507 is not an essential component, and equivalent processing can also be executed by the CPU 501.

[0051] The operation panel 506 includes, for example, a display unit composed of a liquid crystal display or the like, and an input unit composed of a touch panel, various keys, and the like. The display unit displays the current status and setting information of the recording device 100 input from the CPU 501. The input unit inputs the information input by the user's operation to the CPU 501. For example, a recording start instruction, various setting information, and the like are input.

[0052] Note that instead of the operation panel 506, the host device 530 may function as the operation unit of the recording device 100. In that case, the current status and setting information of the recording device 100 are transmitted from the CPU 501 to the host device 530 and displayed on the host device 530. Also, a recording start instruction, various setting information, and the like are input by the user of the host device 530 and input to the CPU 501.

[0053] The sensor 519 includes a sensor for detecting the remaining amount of ink in the tank, a sensor for detecting the conveyance position of the sheet, and the like.

[0054] Next, the functional configuration of the recording device 100 according to the present embodiment will be described. FIG. 6 is a block diagram showing the functional configuration of the recording device 100. The control unit 500 of the recording device 100 includes a conveyance control unit 601, a head carriage control unit 602, an ink circulation control unit 603, an ink agitation control unit 604, a counter 605, a maintenance control unit 610, and the like. The maintenance control unit 610 includes a return timer 611, a maintenance content determination unit 612, a maintenance start time setting unit 613, and the like. In the present embodiment, each of these functional units is realized by the CPU 501 calling a program stored in the ROM 502 or the storage device 504 and executing processing according to the program.

[0055] The conveyance control unit 601 drives the conveyance motor of the conveyance unit 105 to control the conveyance and stop of the sheet P. The head driver 518 discharges ink from the recording head 101 in accordance with the recording data transmitted from the control unit 500 in conjunction with the conveyance operation of the sheet.

[0056] The head carriage control unit 602 controls the position and orientation of the head carriage unit 521 on which the recording head 101 is mounted to change according to the operating state of the recording apparatus 100. The operating states include a recording state, a maintenance state, a cap state, and the like.

[0057] When shifting from the maintenance state to the recording state, the head carriage control unit 602 moves the position of the recording head 101 in the vertical direction (Y direction) to the recording position. When shifting from the recording state to the maintenance state or the cap state, the head carriage control unit 602 moves the position of the recording head 101 in the vertical direction to a predetermined maintenance position or cap position. In the maintenance state or the cap state, the head carriage control unit 602 changes the lateral relative position between the recording head 101 and the maintenance unit 520 so that the maintenance unit 520 or the head cap enters below the recording head 101.

[0058] Regarding the orientation of the recording head 101, when shifting to the recording state, the head carriage control unit 602 adjusts and fixes the angle of the recording head 101 so that the ink ejection surface of the recording head 101 faces parallel to the recording surface of the sheet P. When using a roll sheet, the sheet surface is often kept in a curved state to maintain the tension of the sheet. Therefore, the orientation of each color recording head 101 is adjusted and fixed so that the ink ejection surface faces parallel to the recording surface of the sheet P.

[0059] During the recording operation, the ink circulation control unit 603 controls the ink circulation unit 200 so that the pressure of the ink supplied to the recording head 101 remains within an appropriate range. Also, even during the pause period of the recording operation, the ink circulation control unit 603 controls the ink circulation unit 200 according to the schedule set by the maintenance control unit 610 to circulate the ink. For example, ink circulation is executed during the pre-return maintenance, the first intermittent maintenance, and the second intermittent maintenance described later. However, the first intermittent maintenance and the second intermittent maintenance include non-operating times when the ink circulation is paused.

[0060] The ink agitation control unit 604 controls the ink agitation unit 220 according to the schedule set by the maintenance control unit 610 to agitate the ink in the tank 102. For example, ink agitation in the tank is executed during the pre-return maintenance, the first intermittent maintenance, and the second intermittent maintenance described later. However, the first intermittent maintenance and the second intermittent maintenance include non-operating times when the ink agitation is paused.

[0061] The counter 605 is a real-time clock or the like and manages time and time points. The time and time points to be managed include the start time and end time of maintenance, the start time and end time (return time) of the pause period, and other time points when an instruction is input. Also, the start time and stop time of ink circulation and ink agitation are measured by the counter 605 and held in the RAM 503 as a log.

[0062] The maintenance control unit 610 controls the maintenance operations for the ink, including ink circulation by the ink circulation unit 200 and ink agitation in the tank using the ink agitation unit 220 (hereinafter referred to as ink agitation). Also, the maintenance control unit 610 controls the maintenance operations for the recording head 101 using the maintenance unit 520.

[0063] The maintenance operation for the recording head 101 includes ink suction inside the nozzles by the cap suction unit 522 and wiping of the nozzle surface by the wipe unit 523. The cap suction unit 522 seals the ink ejection surface (nozzle surface) of the recording head 101 with a cap, and discharges the ink and foreign matter inside the nozzles by reducing the pressure inside the cap. The wipe unit 523 includes a suction wipe unit and a blade wipe unit. The suction wipe unit has a suction port shorter than the length of the nozzle array of the recording head 101, and discharges the ink and foreign matter inside the nozzles while moving the suction port in the direction in which the nozzles are arranged with a negative pressure applied. The blade wipe unit wipes with a rubber blade without a suction unit to remove the ink and foreign matter on the nozzle surface.

[0064] The maintenance control unit 610 controls the maintenance operation of the recording apparatus 100. In the present embodiment, the maintenance control unit 610 controls so that the pre - return maintenance is completed before the time of returning from the pause period. In the pre - return maintenance, the maintenance control unit 610 controls the ink circulation unit 200 to execute ink circulation, and controls the ink agitation unit 220 to execute ink agitation in the tank 102. By the ink circulation, the ink in the recording head 101, the tank 102, and the flow path circulates, and the density unevenness is reduced. By the ink agitation, the ink in the tank 102 is agitated, and the density unevenness is reduced.

[0065] As a function for controlling the maintenance during the pause period, the maintenance control unit 610 includes a return timer 611, a maintenance content determination unit 612, and a maintenance start time setting unit 613.

[0066] The return timer 611 is a timer for the user to set the return time from the standby state (or recording state), which is a state where the recording operation is executable, to the standby state from the standby state where the recording operation has stopped, or the length of the standby period (standby period), which is the standby time. When the date and time are set in the return timer 611, the maintenance control unit 610 sets the set date and time as the return time. When the standby time is set in the return timer 611, the maintenance control unit 610 sets the time when the set standby time has elapsed from the start time of the standby period as the return time.

[0067] Regarding the return time, the user can arbitrarily set the return time, such as specifying the time for each day of the week, specifying a specific date and time (for example, 9:00 am on Monday, Tuesday, Wednesday, Thursday, Friday, or 9:00 am on April 1, 2023). Also, regarding the standby time, the user can arbitrarily set the length of time, such as 5 hours, 5 days, or 5 weeks. In this embodiment, the setting of these return times or standby times is referred to as the setting of the return timer.

[0068] FIG. 7 is a diagram showing an example of a setting screen for the return timer. FIG. 7(a) is an example of a setting screen 710 that accepts the setting of the return time. FIG. 7(b) is an example of a setting screen 720 that accepts the setting of the standby time. When a setting request for the return timer is input from the host device 530 to the recording device 100, the control unit 500 transmits the setting screen 710 shown in FIG. 7(a) or the setting screen 720 shown in FIG. 7(a) to the host device 530 and displays it. When the setting values input by the user of the host device 530 to the setting screens 710 and 720 are transmitted to the recording device 100, the control unit 500 receives the setting values and stores them in the RAM 503 as the setting values of the return timer.

[0069] The setting screen 710 is provided with a schedule setting column 711 for setting the days of the week and times to resume from the pause period, and a date and time setting column 714 for setting a specific date and time (next resume date and time) to resume from the pause period. The schedule setting column 711 is provided with a check box 712 and a time input column 713 for each day of the week, and the time input into the time input column 713 becomes valid for the checked days of the week. In the example of the figure, since Monday, Tuesday, Wednesday, Thursday, and Friday are checked and 8:30 is input, 8:30 on Monday, Tuesday, Wednesday, Thursday, and Friday is set in the resume timer as the resume time. The time display 701 on the setting screen 710 shows the current date and time. When the menu button 702 is operated, the screen transitions to the menu screen, and when the pause transition button 703 is operated, it transitions to the pause state after executing the process shown in FIG. 9.

[0070] The setting screen 720 is provided with a pause time setting column 721 for setting the pause time, a menu button 702, and a pause transition button 703. The time display 701 on the setting screen 720 shows the current date and time. When the pause transition button 703 is operated with a length of time input into the pause time setting column 721, the resume time is set in the resume timer so as to resume from the pause state at the time after the set pause time has elapsed. Then, the pause period is started. Note that the pause time setting column 721 may be provided on the setting screen 710 shown in FIG. 7(a).

[0071] As described above, the maintenance control unit 610 performs pre-resume maintenance including ink circulation and ink agitation so as to complete it before the resume time set by the resume timer 611. Therefore, the maintenance start time setting unit (hereinafter referred to as the start time setting unit 613) sets the start time of the pre-resume maintenance. Hereinafter, the resume time is t e and the start time of the pre-resume maintenance is t s are denoted.

[0072] The start time setting unit 613 sets the start time t e of the pre-resume maintenance to the time that is at least the time required for the pre-resume maintenance retrogressed from the resume time t sis set. When the start time t set by the start time setting unit 613 is reached, the pre-return maintenance is started under control. s The setting of the return time t

[0073] or the pause time T e by the user (the setting of the return timer 611) is performed before shifting to the pause period, and it is preferable that the maintenance control unit 610 acquires the return time before shifting to the pause period. When the return timer 611 is set before shifting to the pause period, the maintenance control unit 610 determines the start time t of the pre-return maintenance before shifting to the pause period based on the return time t d set in the return timer 611 or the pause time T e or the pause time T d . Note that since the pre-return maintenance is a preparation operation before starting the recording operation, it is preferably performed at a time close to the return time. More preferably, the pre-return maintenance is preferably executed immediately before the return time. s

[0074] In addition, the maintenance content determination unit 612 (hereinafter referred to as the determination unit 612) of the maintenance control unit 610 determines the processing content of the pre-return maintenance based on the elapsed time T c . The elapsed time T c is the length of time during which the ink circulation is not performed. Specifically, the elapsed time T c is the time from the end time of the last ink circulation executed before shifting to the pause period to the return time t e .

[0075] FIG. 8 is a diagram showing an example of a table 800 in which the maintenance content according to the elapsed time T c is determined in advance. Note that the example in FIG. 8 shows the case where the ink stirring unit 220 is mounted only on the tank 102 for white (W) and metallic ink and not on the tank 102 for color ink (C, M, Y, K).

[0076] The elapsed time T cWhen it is 0 hours or more and less than 3 hours, for white and metallic inks, ink circulation and ink agitation are each carried out for 15 minutes. For color inks, ink circulation and ink agitation are not carried out.

[0077] Standing time T c When it is 3 hours or more and less than 6 hours, for white and metallic inks, ink circulation and ink agitation are each carried out for 30 minutes. For color inks, ink circulation is carried out for 15 minutes.

[0078] Standing time T c When it is 6 hours or more and less than 11 hours, for white and metallic inks, ink circulation and ink agitation are each carried out for 45 minutes. For color inks, ink circulation is carried out for 15 minutes.

[0079] Standing time T c When it is 11 hours or more, for white and metallic inks, ink circulation and ink agitation are each carried out for 60 minutes, and further, for nozzle cleaning of the recording head 101, nozzle blade wiping and nozzle suction wiping are carried out. For color inks, ink circulation is carried out for 30 minutes, and further, nozzle blade wiping and nozzle suction wiping are carried out.

[0080] In the example of FIG. 8, different processing contents are set for color inks and white / metallic inks, respectively. The operating time of ink circulation for color inks is set to be equal to or less than the operating time of ink circulation for white / metallic inks. This is because depending on the type of ink, the ease of reducing density unevenness by ink circulation and ink agitation in the tank varies. For example, specific types of inks with a high specific gravity of colorants, such as white inks containing white pigments such as titanium oxide and metallic inks containing metal pigments such as aluminum, tend to sediment. Therefore, it takes more time to reduce density unevenness by ink circulation and ink agitation in the tank compared to general color inks (C, M, Y, K).

[0081] Also, the ink circulation and the ink agitation may be started simultaneously, or the ink agitation may be executed prior to the ink circulation. Further, when the ink agitation units 220 are provided in the tanks 102 for the color inks respectively, not only the ink circulation but also the ink agitation may be performed. Also, the information shown in the table 800 may be preset and stored in the RAM 503 or the ROM 502, or may be settable by the user. The standing time T shown in FIG. 8 c The relationship with the processing content is an example and is not limited to this example, and any processing content can be set for any standing time T c The processing content can be set arbitrarily for any standing time T

[0082] The table 800 shown in FIG. 8 is referred to when the determination unit 612 determines the processing content of the maintenance

[0083] Furthermore, the maintenance control unit 610 may intermittently execute the ink circulation and the ink agitation at a predetermined time interval during the pause period

[0084] For example, when the setting of the return timer 611, that is, the setting of the return time t e is not performed before the transition to the pause period, the maintenance control unit 610 controls to execute the first intermittent maintenance during the pause period. The first intermittent maintenance is a maintenance process in which the ink circulation unit 200 and the ink agitation unit 220 are intermittently operated at a predetermined time interval. The first intermittent maintenance includes the ink circulation and the ink agitation

[0085] Also, when the setting of the return timer 611, that is, the setting of the return time t e is performed before the transition to the pause period, and the standing time T c is greater than or equal to the threshold value T h the maintenance control unit 610 controls to execute the second intermittent maintenance. The second intermittent maintenance is from the transition time t a to the start time t of the pre-return maintenance sDuring this period, the ink circulation unit 200 and the ink agitation unit 220 perform maintenance processes intermittently at predetermined time intervals. The second intermittent maintenance includes ink circulation and ink agitation. Details of the first and second intermittent maintenance will be described later.

[0086] Also, before shifting to the rest period, the return timer 611 is set, that is, the return time t e is set, and when the idle time T c is shorter than the threshold value T h , the maintenance control unit 610 may perform only the pre-return maintenance without performing the second intermittent maintenance. This is because if the idle time T c is short, sedimentation and density unevenness are less likely to occur, so priority is given to reducing the operating time of the ink circulation unit 200 such as a pump to suppress the consumption of the pump and the like. The replacement frequency of parts such as the pump is reduced, and an improvement in productivity can be expected.

[0087] The threshold value T c of the idle time T h for determining whether to perform the second intermittent maintenance is preferably shorter than the time when ink circulation failure or ink agitation failure occurs due to ink sedimentation and deposition, and a problem occurs in the recording apparatus 100. Specific examples of the problem include, for example, ink ejection failure due to blockage of the nozzle flow path. In addition, streaks due to insufficient refilling due to the influence of the blockage are also included. This streak tends to occur mainly when the recording duty is high. Also, density unevenness may occur if there is not enough time for pre-return maintenance even without blockage.

[0088] The risks of these problems vary greatly depending on the ink composition, but in some cases, they can be recovered by taking sufficient time for pre-return maintenance. Specifically, in the case of white ink containing titanium oxide, if the circulation and agitation are stopped for one week, several hours of maintenance is required for recovery. Conversely, in order to be able to recover with maintenance within one hour, it is preferable to control the circulation and agitation at intervals of 24 hours as a guide.

[0089] Further, the recording apparatus 100 may receive an input of a manual return instruction by the user during the pause period. When a manual return instruction by the user is input during the pause period, the maintenance control unit 610 immediately starts the pre-return maintenance.

[0090] Thus, during the pause period, if a manual return is instructed before the return time t e the user needs to wait until the pre-return maintenance performed after the return instruction to the recordable state ends. Therefore, when determining the processing content and threshold value T h of the maintenance, it is preferable to consider the relationship between the above-described leaving time T c and the time for recovery, as well as the productivity due to pump consumption and the allowable waiting time. For example, when the allowable waiting time is set to a maximum of 1 hour, it is preferable to set the operating time and non-operating time of the first and second intermittent maintenances so that the ink state is restored by the pre-return maintenance for 1 hour.

[0091] Further, the determination unit 612 preferably determines the processing content of the pre-return maintenance based on the time (hereinafter referred to as the elapsed time T f ) between the time when a return to the recordable state is instructed and the end time of the last ink circulation executed before that time.

[0092] Further, the processing content of the pre-return maintenance may include maintenance of the recording head 101 by the cap suction unit 522 and the wipe unit 523.

[0093] In the above-described first intermittent maintenance, ink circulation and ink agitation are repeatedly executed intermittently at a predetermined time interval. That is, the operation and non-operation of the ink circulation and the ink agitation are alternately repeated. Similarly, in the above-described second intermittent maintenance, ink circulation and ink agitation are repeatedly executed intermittently at a predetermined time interval. That is, the operation and non-operation of the ink circulation and the ink agitation are alternately repeated.

[0094] However, the relationship between the ratio X1 of the operating time to the non-operating time of the ink circulation unit 200 in the first intermittent maintenance and the ratio Y1 of the operating time to the non-operating time of the ink circulation unit 200 in the second intermittent maintenance is preferably X1 ≥ Y1. Here, X1 is the operating time for one non-operating time of one of the multiple intermittent operations included in the first intermittent maintenance. Similarly, Y1 is the operating time for one non-operating time of one of the multiple intermittent operations included in the second intermittent maintenance.

[0095] Also, the relationship between the ratio X2 of the operating time to the non-operating time of the ink stirring unit 220 in the first intermittent maintenance and the ratio Y2 of the operating time to the non-operating time of the ink stirring unit 220 in the second intermittent maintenance is preferably X2 ≥ Y2. Here, X2 is the operating time for one non-operating time of one of the multiple intermittent operations included in the first intermittent maintenance. Similarly, Y2 is the operating time for one non-operating time of one of the multiple intermittent operations included in the second intermittent maintenance.

[0096] This is to shorten the time of pre-return maintenance, that is, the user's waiting time, which starts after the user manually gives a return instruction without a return timer being set. By making the ratio of the operating time of ink circulation or ink stirring in the first intermittent maintenance, which is executed when the return timer is not set, such as X1 ≥ Y1 or X2 ≥ Y2, larger than the ratio in the second intermittent maintenance, the time required for pre-return maintenance can be shortened. Thereby, the user's waiting time after the return instruction input can be shortened.

[0097] The relationship between the operating time A1 of ink circulation due to pre-return maintenance and the operating time B1 of ink circulation due to the second intermittent maintenance is preferably A1 ≤ B1. Here, B1 is the operating time for one of the multiple intermittent operations included in the second intermittent maintenance.

[0098] Also, the relationship between the operation time A2 of ink agitation during pre-return maintenance and the operation time B2 of ink agitation during the second intermittent maintenance is preferably A2 ≤ B2. Here, B2 is the operation time for one of the multiple intermittent operations included in the second intermittent maintenance.

[0099] This is because the time of pre-return maintenance starts after the user manually gives a return instruction before the scheduled start time t s of pre-return maintenance, that is, to minimize the waiting time of the user. By setting the operation time in the second intermittent maintenance, which is executed when the idle time T c is long, such as A1 ≤ B1 or A2 ≤ B2, to be longer than the operation time in pre-return maintenance, the time required for pre-return maintenance can be shortened. Thereby, the waiting time of the user after the return instruction input can be shortened.

[0100] Also, the ink agitation in pre-return maintenance, the first intermittent maintenance, and the second intermittent maintenance is preferably started simultaneously with or prior to ink circulation.

[0101] Also, the relationship between the ratio X1 of the operation time to the non-operation time of ink circulation in the first intermittent maintenance and the ratio X2 of the operation time to the non-operation time of ink agitation in the first intermittent maintenance is preferably set to satisfy X1 ≤ X2. This is to prevent the fine structure inside the recording head 101 from being blocked by the ink in the tank 102 with increased concentration due to sedimentation.

[0102] Also, in the first intermittent maintenance or the second intermittent maintenance, it is preferable to control so that ink is not ejected from the recording head 101. This is to reduce the uneven ink concentration in the recording head 101 by ink circulation and suppress an increase in the ink usage amount due to ink ejection.

[0103] Next, the relationship between the presence or absence of the setting of the return timer and the maintenance operation will be described. FIG. 9 is a flowchart showing the flow of processing executed when the recording apparatus 100 receives a standby transition instruction. The processing shown in this flowchart is described in a program stored in the ROM 502 or the storage device 504 of the recording apparatus 100. The program is called by the CPU 501, expanded in the RAM 503, and executed. When receiving a standby transition instruction from the host device 530 or the operation panel 506 (S900), the CPU 501 starts the processing shown in this flowchart. In the following description, the symbol "S" means step.

[0104] In S901, the CPU 501 checks whether the return timer 611 is set by the user. If the return timer 611 is set, the process proceeds to S902. If the return timer 611 is not set, the process proceeds to S908.

[0105] In S902, the CPU 501 calculates the idle time T c . The idle time T c is the time length from the end time of the last ink circulation performed before receiving the standby transition instruction to the return time t e set by the return timer 611.

[0106] In S903, the CPU 501 determines whether the idle time T c is equal to or longer than a predetermined time (threshold value T h ). If the idle time T c is shorter than the predetermined time (threshold value T h ), the process proceeds to S904.

[0107] In S904, the CPU 501 sets the processing content of the pre-return maintenance based on the idle time T c calculated in S902. The processing content of the pre-return maintenance for the idle time T c is, for example, preset in the table 800 shown in FIG. 8 and stored in the RAM 503 or the ROM 502. The CPU 501 uses the idle time T cDetermine the content of the pre-return maintenance according to the situation.

[0108] In S905, the CPU 501 determines the start time t of the pre-return maintenance as the time obtained by going back from the set return time t e by the time required for the pre-return maintenance. s Then, it proceeds to S906 and shifts to the standby state.

[0109] In S903, if the elapsed time T c is determined to be equal to or more than a predetermined time (threshold value T h ), it proceeds to S907.

[0110] In S907, the CPU 501 sets to execute the second intermittent maintenance after the standby transition, and then executes the processes of S904 to S906. The time interval and processing content of the second intermittent maintenance may be set in advance, or may be determined according to the elapsed time T c , or may be determined according to the allowable waiting time of the user as described above.

[0111] If it is determined in S901 that the return timer 611 is not set, it proceeds to S908.

[0112] In S908, the CPU 501 sets to execute the first intermittent maintenance after the standby transition. Then, it proceeds to S906 and shifts to the standby state. The time interval and processing content of the first intermittent maintenance may be set in advance, or may be determined according to the allowable waiting time of the user.

[0113] A specific example of the maintenance operation according to the setting of the return timer 611 will be described. FIG. 10 is an example (1) when the return time t e is set in the return timer 611. The rightward arrow in FIG. 10 indicates the time axis [t]. The time when the standby transition instruction is input to the control unit 500 is t a , and the end time of the last ink circulation before the standby transition (ink circulation stop time) is t b, let the start time of pre-return maintenance be t s , let the return time be t e as shown. Also, the pause period is T d , the idle time is T c as shown. The threshold T h for determining whether to set the second intermittent maintenance is 20 hours.

[0114] In the example of Fig. 10, a pause transition instruction is input at "17:00 on March 31" (time t a ), and the return time t e of the return timer 611 is set to "8:30 on April 1". Note that the ink circulation stop time t b is "16:30 on March 31".

[0115] The CPU 501 calculates the idle time T b from the ink circulation stop time t e (16:30 on March 31) and the return time t c (8:30 on April 1). As a result, the idle time T c is calculated to be 16 hours. In this case, since the idle time T c is shorter than the threshold T h (20 hours), the second intermittent maintenance is not executed.

[0116] Also, the processing content of the pre-return maintenance is set based on the length of the idle time T c . Referring to Fig. 8, when the idle time T c is 11 hours or more, 60 minutes of ink circulation and ink agitation are set for white / metallic ink. Also, nozzle blade wiping and nozzle suction wiping are set to be executed for the recording head 101. For color ink, 30 minutes of ink circulation is set. Also, nozzle blade wiping and nozzle suction wiping are set to be executed for the recording head 101.

[0117] The CPU 501 sets the start time t s of the pre-return maintenance for white / metallic ink to the return time te It is set to 7:30 on April 1, which is 60 minutes before , and shifts to the standby state. The start time t of the pre-return maintenance for the color ink s is set to 8:00 on April 1, but the notation is omitted in Fig. 10.

[0118] During the standby period, the time is managed by the counter 605. The CPU 501 starts the pre-return maintenance when it reaches the start time t of the pre-return maintenance s and ends the pre-return maintenance before the return time. After that, the CPU 501 sets the operating state to a state where recording can be started.

[0119] Fig. 11 shows an example (2) when the return time t e is set in the return timer 611. Different from the example shown in Fig. 10, the return time t e is set to "8:30 on April 10". In this case, the idle time T c is 9 days and 16 hours, and since it is equal to or greater than the threshold value T h (20 hours), it is set so that the second intermittent maintenance is executed by the CPU 501.

[0120] In the example of Fig. 11, in the second intermittent maintenance, the ink circulation and ink agitation are repeatedly performed as 1 hour of operating time after 23 hours of non-operating time. Note that the content of the pre-return maintenance is the same as in the example of Fig. 10. For white / metallic ink, 60 minutes before the return time t e is set as the start time t of the pre-return maintenance s . Therefore, "7:30 on April 10" is set as the start time t of the pre-return maintenance s . The start time t of the pre-return maintenance for the color ink s is set to "8:00 on April 1", but the notation is omitted in Fig. 11.

[0121] Fig. 12 shows an example (1) when the standby time T d (the length of the standby period) is set in the return timer 611. In the example of Fig. 12, "17:00 on March 31" (time ta ) A pause transition instruction is input, and the pause time T is set in the return timer 611 d (pause period) is set to "15 hours 30 minutes". The end time of the last ink circulation before transitioning to the pause state (ink circulation stop time t b ) is set to "March 31, 16:30". Also, the return time te is the time elapsed from the time t a when the pause transition instruction was input to the pause time T d and is calculated by the CPU 501 as "April 1, 8:30".

[0122] The CPU 501 calculates the time from the ink circulation stop time t b (March 31, 16:30) to the pause transition instruction (March 31, 17:00), which is 30 minutes, and the hold time T d (15 hours 30 minutes) set in the return timer 611 to calculate the standby time T c . As a result, the standby time T c is calculated to be 16 hours. In this case, the standby time T c is shorter than the threshold T h (20 hours), so the second intermittent maintenance is not set.

[0123] Also, the content of the pre-return maintenance is set based on the length of the standby time T c . As a result, similar to the example in Figure 10, 60 minutes of ink circulation and ink agitation are set for white / metallic ink. Also, nozzle blade wiping and nozzle suction wiping are set to be executed. For color ink, 30 minutes of ink circulation is set. Also, nozzle blade wiping and nozzle suction wiping are set to be executed.

[0124] The CPU 501 sets the start time t s of the pre-return maintenance for white / metallic ink to 7:30 on April 1 and transitions to the pause state. The start time t s of the pre-return maintenance for color ink is set to 8:00 on April 1, but the notation is omitted in Figure 12.

[0125] Figure 13 shows an example (2) when a pause time T is set in the return timer 611. d This is different from the example shown in Figure 12 in that the pause time T is set to "9 days and 15 hours 30 minutes". In this case, the idle time T d is 9 days and 16 hours, and since the threshold value T c is 20 hours or more, it is set so that the second intermittent maintenance is executed by the CPU 501. h (20 hours) or more, it is set so that the second intermittent maintenance is executed by the CPU 501.

[0126] In the example of Figure 13, in the second intermittent maintenance, ink circulation and ink agitation are repeatedly performed as 1 hour of operation time after 23 hours of non-operation time. The content of the pre-return maintenance is the same as in the example of Figure 10. For white / metallic ink, 60 minutes before the return time t e is set as the start time t of the pre-return maintenance s . Therefore, "7:30 on April 10" is set as the start time t of the pre-return maintenance s . The start time t of the pre-return maintenance for color ink s is set to "8:00 on April 1", but the notation is omitted in Figure 13.

[0127] Figure 14 shows an example of the maintenance operation when the return timer 611 is not set. In this case, the length of the pause period and the return time t e are undetermined. When a pause transition instruction is input, the CPU 501 sets to execute the first intermittent maintenance during the pause period and then transitions to the pause state.

[0128] In the example of Figure 14, in the first intermittent maintenance, ink circulation and ink agitation are repeatedly performed as 1 hour of operation time after 11 hours of non-operation time. Also, the pre-return maintenance is started when a return instruction is manually input by the user. In the example of Figure 14, a return instruction is input at "8:30 on April 10". The CPU 501 acquires the end time of the last ink circulation before the return instruction is input, and the elapsed time T from that time until the time when the return instruction is inputf According to this, the content of the pre-return maintenance is determined. Then, the pre-return maintenance is immediately started.

[0129] In the example of FIG. 14, the time when the return instruction is input is "8:30 on April 10th", and the end time of the last ink circulation before that time is "5:00 on April 10th". Therefore, the elapsed time T f is 3 hours and 30 minutes. Referring to the "idle time" in the table of FIG. 8 as the "elapsed time", when the elapsed time is 3 hours and 30 minutes, for white / metallic ink, an ink circulation and ink stirring for 30 minutes are set. For color ink, an ink circulation for 15 minutes is set.

[0130] Therefore, after the time "8:30 on April 10th" when the return instruction is input, as soon as the processing content is determined, the pre-return maintenance is started. For white / metallic ink, the pre-return maintenance is executed for 30 minutes and ends at "9:00 on April 10th". For color ink, the pre-return maintenance is executed for 15 minutes and ends at "8:45 on April 10th", but the notation in FIG. 14 is omitted.

[0131] Next, the processing executed by the CPU 501 during the pause period (pause state) will be described. FIG. 15 is a flowchart showing the flow of processing executed by the CPU 501 after transitioning to the pause state. Note that the processing shown in FIG. 15 starts together with the start of the pause state (S1500).

[0132] When transitioning to the pause state without setting the return timer 611, it is set to execute the first intermittent maintenance by the processing of FIG. 9. Therefore, the start times and operation times (or end times) of one or more ink circulations and ink stirrings are set by the CPU 501. The start times and operation times (or end times) are determined based on the operation times and non-operation times of the ink circulation and ink stirring in the first intermittent maintenance. The start time and processing content of the pre-return maintenance are in an undetermined state.

[0133] When shifting to the standby state after the return timer 611 is set, the start time t of the maintenance before return is determined by the process of FIG. 9 s and the processing content has been determined. Furthermore, the elapsed time T c is longer than the threshold value T h and when it is set to execute the second intermittent maintenance, the start time and the operation time (or end time) of the ink circulation and the ink agitation in the second intermittent maintenance are set for one or more times. The start time and the operation time (or end time) of the ink circulation and the ink agitation are determined based on the operation time and the non-operation time of the ink circulation and the ink agitation in the second intermittent maintenance.

[0134] In S1501, the CPU 501 determines whether there is a manual return instruction by the user. If no manual return instruction is input, the process proceeds to S1502. If a return instruction is input, the process proceeds to S1506. Note that the manual return instruction can be input regardless of whether the return timer 611 is set.

[0135] In S1502, the CPU 501 determines whether the start time of the first intermittent maintenance or the second intermittent maintenance has been reached. If the start time of the first intermittent maintenance or the second intermittent maintenance has been reached, the process proceeds to S1503.

[0136] In S1503, the CPU 501 instructs to start the maintenance. The CPU 501 instructs the ink circulation unit 200 and the ink agitation unit 220 to start the maintenance according to the maintenance processing content. The ink circulation unit 200 and the ink agitation unit 220 execute the maintenance process including the ink circulation and the ink agitation according to the instruction from the CPU 501. When the operation time has elapsed (or when the end time is reached), the CPU 501 stops the maintenance process.

[0137] If it is determined in the determination of S1502 that the start time of the first intermittent maintenance or the second intermittent maintenance has not been reached, or after a maintenance instruction is given in S1503, the process proceeds to S1504.

[0138] In S1504, the CPU 501 determines whether the start time t s of the pre - return maintenance has been reached. If the start time t s of the pre - return maintenance has been reached, the process proceeds to S1505. If the start time t s of the pre - return maintenance has not been reached, the process returns to S1501.

[0139] In S1505, the CPU 501 instructs to start the pre - return maintenance. The CPU 501 instructs the ink circulation unit 200 and the ink agitation unit 220, or the maintenance unit 520, to start maintenance according to the maintenance processing content determined by the processing shown in FIG. 9. The ink circulation unit 200 and the ink agitation unit 220, or the maintenance unit 520, execute maintenance processing including ink circulation and ink agitation according to the instruction from the CPU 501. When the operation time has elapsed (or when the end time has been reached), the CPU 501 stops the maintenance processing.

[0140] In S1501, if it is determined that a return instruction has been manually input by the user, in S1506, the CPU 501 calculates the elapsed time T f . The elapsed time T f is the time from the time when the last ink circulation ended before the return instruction was input to the time when the return instruction was input.

[0141] Specifically, if the return instruction is input after the transition to the standby state and before the first or second intermittent maintenance is performed, the elapsed time T f is the time from the end time of the last ink circulation executed before the transition to the standby period to the time when the return instruction was input (= the elapsed time T c) That is, if a return instruction is input after the first or second intermittent maintenance has been performed at least once after transitioning to the standby state, the elapsed time T f is defined as follows. The elapsed time T f is the time from the end time of ink circulation in the first or second intermittent maintenance performed immediately before the return instruction is input to the time when the return instruction is input.

[0142] In S1507, the CPU 501 determines the processing content of the pre-return maintenance based on the calculated elapsed time T f . For example, the CPU 501 reads the "idle time T c " in the table 800 shown in FIG. 8 as "elapsed time T f ", and determines the processing content of the maintenance according to the elapsed time T f . Then, it proceeds to S1505, and the CPU 501 instructs to execute the pre-return maintenance with the processing content determined in S1507, and ends this flowchart.

[0143] As described above, after the return instruction is input, the processing content of the maintenance and the idle time T c are determined in consideration of the allowable waiting time until the pre-return maintenance is completed, and the relationship between the operating time and the non-operating time in the first and second intermittent maintenances. Therefore, the user's waiting time is suppressed within the allowable waiting time.

[0144] As described above, the recording apparatus 100 according to the present embodiment executes pre-return maintenance including ink circulation after a predetermined standby period, and completes the pre-return maintenance before the return time set by the return timer 611. As a result, since a standby period is provided, the operating time of the ink circulation unit 200 is reduced. In addition, the user's waiting time until the ink can be ejected without density unevenness after returning from the standby state can be shortened. Further, since intermittent maintenance is performed at predetermined time intervals during the standby period, the maintenance time before return can be shortened.

[0145] Even when the return timer is not set, intermittent maintenance is performed at predetermined time intervals during the pause period, so that the time required for pre-return maintenance executed after a return instruction is input can be shortened. Therefore, it is possible to shorten the time until the ink can be ejected in a state without density unevenness after returning from the pause state.

[0146] In the recording apparatus 100 of the first embodiment, in the pre-return maintenance, the first and second intermittent maintenances, an example in which ink circulation and ink agitation are performed for white and metallic inks, and ink circulation is performed for color inks has been shown. However, the processing content of the maintenance is not limited to this. For all ink types, maintenance processing including ink circulation and ink agitation may be performed, or only ink circulation may be performed in each maintenance process for all ink types. Further, an example in which the return timer 611 is set before shifting to the pause period has been shown, but it is not limited to this example, and the setting of the return timer 611 may be accepted after shifting to the pause period. When the return timer 611 is set after shifting to the pause period, the CPU 501 sets the start time t e of the pre-return maintenance based on the return time t s set in the return timer 611. Further, for example, the time from the end time of the last ink circulation before the time when the return timer 611 is set to the return time t e is calculated as the standstill time T c , and it is preferable to determine the processing content of the pre-return maintenance according to the standstill time T c .

[0147] Also, an example in which the allowable user waiting time after the return instruction is input is set to a maximum of 1 hour has been shown, but it is not limited to this example and may be any time. Also, the allowable user waiting time may be configured to be set by the user.

[0148] <Second Embodiment> Next, a second embodiment of the present disclosure will be described. In a recording apparatus capable of using a plurality of types of inks, such as white ink and color ink, the maintenance content can be set differently depending on the type of ink (see FIG. 8). In that case, even if maintenance is started at the same time, the time when maintenance ends differs depending on the type of ink.

[0149] Therefore, in the recording apparatus 100 of the second embodiment, when maintenance has ended for the ink used in a print job, the print job can be started even if maintenance for other inks is still in progress. As a result, depending on the type of ink used in the image data to be recorded, the user's waiting time may be reduced.

[0150] Since the hardware configuration and functional configuration (FIGS. 1 to 6) of the recording apparatus 100 of the second embodiment are the same as those of the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted. The maintenance process (FIGS. 9 and 15) according to the presence or absence and content of the setting to the return timer is also the same as that of the first embodiment. Further, as shown in FIG. 8, it is assumed that maintenance with different processing contents is preset according to the type of ink.

[0151] In the second embodiment, the CPU 501 manages information on whether or not pre-return maintenance has ended for each type of ink. Further, the CPU 501 controls reception of a print job, analysis, storage, and start of the job data.

[0152] FIG. 16 is a diagram showing an example of a flag (hereinafter referred to as a completion flag 1600) indicating whether or not pre-return maintenance managed by the CPU 501 has been completed. The CPU 501 (maintenance control unit 610) monitors the start and completion of pre-return maintenance for each ink circulation unit 200 provided for each type of ink. When starting pre-return maintenance, the CPU 501 sets the completion flag 1600 to the value "0", and when the pre-return maintenance is completed, the CPU 501 sets the completion flag 1600 to the value "1".

[0153] For example, assume that pre-return maintenance is set for 30 minutes for color ink and 60 minutes for white / metallic ink. In this case, if pre-return maintenance is started simultaneously for both inks, the pre-return maintenance for the color ink will end 30 minutes earlier than that for the white / metallic ink. As shown in FIG. 16, the completion flag 1600 in that state is set to "0" for white (W) ink and "1" for each of the C, M, Y, and K inks.

[0154] FIG. 17 is a flowchart showing the flow of job reception processing executed by the CPU 501 of the recording apparatus 100 according to the second embodiment. This flowchart starts when the recording apparatus 100 receives a print job transmitted from the host apparatus 530.

[0155] In S1701, the CPU 501 receives a print job. The CPU 501 stores the received print job in the RAM 503.

[0156] In S1702, the CPU 501 acquires the maintenance completion flag 1600 for each type of ink. In S1703, the CPU 501 analyzes the print job received in S1701 and identifies the types of ink used by the image data included in the print job.

[0157] In S1704, the CPU 501 checks whether maintenance has been completed for all the types of ink identified in S1703. If the completion flag 1600 is set to "1" (completed) for all the identified types of ink, it is determined as YES in S1704 and the process proceeds to S1705. In S1705, the CPU 501 instructs to start the print job received in S1701.

[0158] On the other hand, if the completion flag 1600 acquired in S1702 is set to "0" (in progress) for any one of the identified types of ink, it is determined as NOS in S1704 and the process proceeds to S1706. In S1706, the CPU 501 waits for the start of the print job received in S1701 and returns to S1702. Thereafter, the CPU 501 repeats the processes of S1702 to S1704, starts recording when maintenance is completed for all the specified ink types, and ends this flowchart.

[0159] As described above, when there are a plurality of ink types, the recording apparatus 100 according to the second embodiment controls to execute maintenance with different contents according to the ink types.

[0160] Furthermore, when the recording apparatus 100 according to the second embodiment receives a print job, it determines whether maintenance of the ink used in the received print job has been completed. When maintenance has been completed for the ink used in the received print job, it controls to start recording related to the print job. Therefore, even when maintenance of all types of ink has not been completed, recording can be started at an earlier timing.

[0161] For example, when receiving a print job that uses only color ink and does not use white ink, the CPU 501 can start a recording process using color ink in parallel while the maintenance of the white ink continues.

[0162] Note that the processing contents of the maintenance shown in the above-described embodiment are merely examples, and the present disclosure is not limited thereto. Since the processing steps and processing time required for maintenance differ depending on the ink composition or environment, it is preferable to set appropriate processing time and processing steps.

[0163] Also, in the above-described embodiment, as shown in FIG. 5, it has been described that the recording apparatus 100 and the host apparatus 530 are connected to each other via a network such as a LAN. However, data transfer between the apparatuses may be performed using a USB memory or the like in an offline state.

[0164] In the above-described embodiment, an example in which the recording apparatus 100 receives the setting of the return timer and the return instruction from the host apparatus 530 has been shown. However, the recording apparatus 100 may accept the setting of the return timer and the return instruction using the operation panel 506 of the recording apparatus 100 itself. The setting screen of the return timer is not limited to the example of the above-described embodiment, and may have an arbitrary screen configuration.

[0165] In the above-described embodiment, an example in which the CPU 501 of the recording apparatus 100 executes the processes of the flowcharts shown in FIGS. 9 and 15 has been shown. However, these processes may be executed by the CPU of the host apparatus 530. In that case, the CPU of the host apparatus 530 determines the start time of the pre-return maintenance, the start times in the first and second intermittent maintenances, the operation time, etc. according to the setting of the return timer, and transmits them to the recording apparatus 100. Further, during the pause period, the CPU of the host apparatus 530 may monitor the start time of the maintenance in the recording apparatus 100, and when the start time is reached, transmit a maintenance start instruction to the recording apparatus 100.

[0166] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. However, the present disclosure is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea disclosed in the present application, and it is naturally understood that they also belong to the technical scope of the present invention.

[0167] <Other Embodiments> The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and having one or more processors in a computer of the system or apparatus read and execute the program. Further, it can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

[0168] Note that the disclosure of the above-described embodiment includes the following configurations.

[0169] (Configuration 1) A recording head that performs a recording operation of ejecting ink to record an image, Circulation means for supplying ink from a tank to the recording head and returning the ink recovered from the recording head to the tank for circulation, Control means for controlling the recording operation by the recording head and the ink circulation by the circulation means, Obtaining means for obtaining a return time which is a time when returning from a first state in which the recording operation is paused to a second state in which the recording operation is executable, An inkjet recording apparatus comprising: The control means executes pre-return maintenance including ink circulation by the circulation means for returning the inkjet recording apparatus to the second state after the inkjet recording apparatus has shifted to the first state, and completes the pre-return maintenance before the return time obtained by the obtaining means. An inkjet recording apparatus characterized by that.

[0170] (Configuration 2) The control means sets a time at least the time required for the pre-return maintenance back from the return time as the start time of the pre-return maintenance, and starts the pre-return maintenance when the set start time is reached. The inkjet recording apparatus according to Configuration 1, characterized by that.

[0171] (Configuration 3) The control means sets the start time before shifting to the first state The inkjet recording apparatus according to Configuration 2, characterized by that.

[0172] (Configuration 4) Further comprising reception means for receiving a setting of the return time by a user, The obtaining means obtains, as the return time, the time received by the reception means before shifting to the first state. The inkjet recording apparatus according to any one of Configurations 1 to 3, characterized by that.

[0173] (Configuration 5) Further comprising reception means for receiving a setting of a period for the first state by the user, Based on the length of the period for the first state received by the reception means before the acquisition means shifts to the first state, the acquisition means acquires the return time The inkjet recording apparatus according to any one of Configurations 1 to 3, characterized in that.

[0174] (Configuration 6) Based on the time from the end time of the ink circulation last executed by the circulation means to the return time before shifting to the first state, the control means determines the processing content of the maintenance before return. The inkjet recording apparatus according to any one of Configurations 1 to 5, characterized in that.

[0175] (Configuration 7) When the acquisition means cannot acquire the return time before shifting to the first state, The control means, After shifting to the first state, a first intermittent maintenance is executed in which ink circulation by the circulation means is intermittently performed at predetermined time intervals. The inkjet recording apparatus according to any one of Configurations 1 to 6, characterized in that.

[0176] (Configuration 8) Before shifting to the first state, the acquisition means acquires the return time, and When the time from the end time of the ink circulation last executed by the circulation means to the return time before shifting to the first state is equal to or greater than a threshold value, The control means, After shifting to the first state, before starting the maintenance before return, a second intermittent maintenance is executed in which ink circulation by the circulation means is intermittently performed at predetermined time intervals. The inkjet recording apparatus according to any one of Configurations 1 to 6, characterized in that.

[0177] (Configuration 9) When a return to the second state is instructed in the first state, the control means immediately starts the pre-return maintenance The inkjet recording apparatus according to any one of Configurations 1 to 8, characterized in that.

[0178] (Configuration 10) the control means Based on the time from the time when the return to the second state is instructed to the end time of the ink circulation that was last executed before that time, the inkjet recording apparatus according to Configuration 9, characterized in that it determines the processing content of the pre-return maintenance.

[0179] (Configuration 11) When the acquisition means cannot acquire the return time before shifting to the first state, the control means After shifting to the first state, it executes a first intermittent maintenance in which the ink circulation by the circulation means is intermittently performed at a predetermined time interval, Before shifting to the first state, the acquisition means acquires the return time, and When the time from the end time of the ink circulation that the circulation means last executed before shifting to the first state to the return time is equal to or greater than a threshold value, the control means After shifting to the first state, before starting the pre-return maintenance, it executes a second intermittent maintenance in which the ink circulation by the circulation means is intermittently performed at a predetermined time interval, The relationship between the ratio X1 of the operating time to the non-operating time of the circulation means in the first intermittent maintenance and the ratio Y1 of the operating time to the non-operating time of the circulation means in the second intermittent maintenance is X1≧Y1 The inkjet recording apparatus according to any one of Configurations 1 to 10, characterized in that.

[0180] (Configuration 12) It further includes stirring means for stirring the ink in the tank, In the pre-return maintenance, the control means causes the stirring means to stir the ink. The inkjet recording apparatus according to any one of Configurations 1 to 6, 9, and 10, characterized in that.

[0181] (Configuration 13) The inkjet recording apparatus further includes a stirring means for stirring the ink in the tank. The first intermittent maintenance includes ink stirring by the stirring means. The inkjet recording apparatus according to Configuration 7, characterized in that.

[0182] (Configuration 14) The inkjet recording apparatus further includes a stirring means for stirring the ink in the tank. The second intermittent maintenance includes ink stirring by the stirring means. The inkjet recording apparatus according to Configuration 8, characterized in that.

[0183] (Configuration 15) When the acquisition means cannot acquire the return time before shifting to the first state, The control means, After shifting to the first state, a first intermittent maintenance is executed in which ink circulation by the circulation means and ink stirring by the stirring means are intermittently performed at a predetermined time interval. When the acquisition means acquires the return time before shifting to the first state, and When the time from the end time of the last ink circulation executed before shifting to the first state to the return time is equal to or greater than a threshold value, The control means, After shifting to the first state, a second intermittent maintenance is executed in which ink circulation by the circulation means and ink stirring by the stirring means are intermittently performed at a predetermined time interval until the pre-return maintenance is started. The relationship between the ratio X2 of the operating time to the non-operating time of the stirring means in the first intermittent maintenance and the ratio Y2 of the operating time to the non-operating time of the stirring means in the second intermittent maintenance is X2 ≥ Y2 The inkjet recording apparatus according to Configuration 12, characterized in that

[0184] (Configuration 16) The relationship between the operating time A1 of the circulation means in the pre-return maintenance and the operating time B1 of the circulation means in the second intermittent maintenance is A1 ≤ B1. The inkjet recording apparatus according to Configuration 8 or Configuration 14, characterized in that

[0185] (Configuration 17) The relationship between the operating time A2 of the stirring means in the pre-return maintenance and the operating time B2 of the stirring means in the second intermittent maintenance is A2 ≤ B2. The inkjet recording apparatus according to Configuration 14 or Configuration 15, characterized in that

[0186] (Configuration 18) The control means starts the ink stirring by the stirring means simultaneously with or prior to the ink circulation by the circulation means The inkjet recording apparatus according to any one of Configurations 12 to 14, characterized in that

[0187] (Configuration 19) When the acquisition means cannot acquire the return time before transitioning to the first state, The control means After transitioning to the first state, the first intermittent maintenance including ink circulation by the circulation means and ink stirring by the stirring means is executed at a predetermined time interval, The relationship between the ratio X1 of the operating time to the non-operating time of the circulation means in the first intermittent maintenance and the ratio X2 of the operating time to the non-operating time of the stirring means in the first intermittent maintenance is X1 ≤ X2 The inkjet recording apparatus according to Configuration 13, characterized in that

[0188] (Configuration 20) The control means is In the first intermittent maintenance or the second intermittent maintenance, control the recording head so as not to eject ink The inkjet recording apparatus according to Configuration 11 or Configuration 15, characterized in that

[0189] (Configuration 21) The recording head is capable of ejecting a plurality of types of ink, The control means independently determines the processing content of the pre-return maintenance for each of the plurality of types of ink The inkjet recording apparatus according to any one of Configurations 1 to 20, characterized in that

[0190] (Configuration 22) When a print job is input before the return time arrives, the control means starts the recording operation according to the print job at the time when the pre-return maintenance for the ink used in the print job is completed The inkjet recording apparatus according to Configuration 21, characterized in that

[0191] (Configuration 23) The inkjet recording apparatus according to any one of Configurations 1 to 22, characterized in that the ink contains white ink

[0192] (Configuration 24) The inkjet recording apparatus according to any one of Configurations 1 to 22, characterized in that the ink contains metallic ink

[0193] (Configuration 25) A recording head that performs a recording operation of ejecting ink to record an image, A control method for an inkjet recording apparatus, comprising: a circulation means for supplying ink from a tank to the recording head and returning the ink recovered from the recording head to the tank for circulation A step of obtaining a return time, which is the time to return from a first state where the recording operation is paused to a second state where the recording operation is executable; After transitioning to the first state, a step of performing pre-return maintenance including ink circulation so that the pre-return maintenance is completed before the return time; A control method characterized by including the above.

[0194] (Configuration 26) A recording head that performs a recording operation of discharging ink to record an image; A program for causing a computer to execute a control method of an inkjet recording apparatus including a circulation unit that supplies ink from a tank to the recording head and returns the ink recovered from the recording head to the tank for circulation, the program including: A step of obtaining a return time, which is the time to return from a first state where the recording operation is paused to a second state where the recording operation is executable; After transitioning to the first state, a step of performing pre-return maintenance including ink circulation so that the pre-return maintenance is completed before the return time; A program including the above.

Claims

1. A recording head that performs a recording operation of discharging ink to record an image, circulation means for supplying ink from a tank to the recording head and returning the ink recovered from the recording head to the tank for circulation, control means for controlling the recording operation by the recording head and the ink circulation by the circulation means, acquisition means for acquiring a return time which is the time to return from a first state in which the recording operation is paused to a second state in which the recording operation is executable, An inkjet recording apparatus comprising: After the inkjet recording apparatus has shifted to the first state, the control means executes pre-return maintenance including ink circulation by the circulation means for returning the inkjet recording apparatus to the second state, and completes the pre-return maintenance before the return time acquired by the acquisition means. An inkjet recording apparatus characterized by that.

2. The control means: sets a time at least as far back as the time required for the pre-return maintenance from the return time as the start time of the pre-return maintenance, and starts the pre-return maintenance when the set start time is reached. The inkjet recording apparatus according to Claim 1.

3. The control means: sets the start time before shifting to the first state The inkjet recording apparatus according to Claim 2, characterized by that.

4. Further comprising reception means for receiving a setting of the return time by a user, The acquisition means acquires, as the return time, the time received by the reception means before shifting to the first state. The inkjet recording apparatus according to any one of Claims 1 to 3, characterized by that.

5. Further comprising reception means for receiving a setting of a period for the first state by a user, The acquisition means acquires the return time based on the length of the period for the first state received by the reception means before shifting to the first state. The inkjet recording apparatus according to any one of Claims 1 to 3, characterized by that.

6. The control means determines the processing content of the pre-return maintenance based on the time from the end time of the ink circulation last executed by the circulation means before shifting to the first state to the return time. The inkjet recording apparatus according to any one of Claims 1 to 3, characterized by that.

7. When the acquisition means cannot acquire the return time before shifting to the first state, the control means after shifting to the first state, executes first intermittent maintenance for intermittently performing ink circulation by the circulation means at a predetermined time interval The inkjet recording apparatus according to claim 1, characterized in that.

8. Before shifting to the first state, the acquisition means acquires the return time, and When the time from the end time of the ink circulation last executed by the circulation means to the return time is equal to or greater than a threshold value before shifting to the first state, the control means After shifting to the first state, before starting the pre-return maintenance, executes second intermittent maintenance for intermittently performing ink circulation by the circulation means at a predetermined time interval The inkjet recording apparatus according to claim 1, characterized in that.

9. When a return to the second state is instructed in the first state, the control means Immediately starts the pre-return maintenance The inkjet recording apparatus according to claim 1, characterized in that.

10. the control means Based on the time from the time when the return to the second state is instructed to the end time of the ink circulation last executed before that time, determines the processing content of the pre-return maintenance. The inkjet recording apparatus according to claim 9, characterized in that.

11. When the acquisition means cannot acquire the return time before shifting to the first state, the control means After shifting to the first state, executes first intermittent maintenance for intermittently performing ink circulation by the circulation means at a predetermined time interval, Before shifting to the first state, the acquisition means acquires the return time, and When the time from the end time of the ink circulation last executed by the circulation means to the return time is equal to or greater than a threshold value before shifting to the first state, the control means After shifting to the first state, before starting the pre-return maintenance, executes second intermittent maintenance for intermittently performing ink circulation by the circulation means at a predetermined time interval, The relationship between the ratio X1 of the operating time to the non-operating time of the circulation means in the first intermittent maintenance and the ratio Y1 of the operating time to the non-operating time of the circulation means in the second intermittent maintenance is X1≧Y1 The inkjet recording apparatus according to claim 1, characterized in that.

12. It further includes stirring means for stirring the ink in the tank, In the pre-return maintenance, the control means causes the stirring means to stir the ink The inkjet recording apparatus according to claim 1, characterized in that.

13. It further includes stirring means for stirring the ink in the tank, The first intermittent maintenance includes ink stirring by the stirring means The inkjet recording apparatus according to claim 7, characterized in that.

14. It further includes stirring means for stirring the ink in the tank, The second intermittent maintenance includes ink stirring by the stirring means The inkjet recording apparatus according to claim 8, characterized in that.

15. When the acquisition means cannot acquire the return time before shifting to the first state, The control means, After shifting to the first state, it executes first intermittent maintenance in which ink circulation by the circulation means and ink stirring by the stirring means are intermittently performed at a predetermined time interval, Before shifting to the first state, the acquisition means acquires the return time, and When the time from the end time of the last ink circulation executed before shifting to the first state to the return time is equal to or greater than a threshold value, The control means, After shifting to the first state, before starting the pre-return maintenance, it executes second intermittent maintenance in which ink circulation by the circulation means and ink stirring by the stirring means are intermittently performed at a predetermined time interval, The relationship between the ratio X2 of the operating time to the non-operating time of the stirring means in the first intermittent maintenance and the ratio Y2 of the operating time to the non-operating time of the stirring means in the second intermittent maintenance is X2≧Y2 The inkjet recording apparatus according to claim 12, characterized in that.

16. The relationship between the operating time A1 of the circulation means in the pre-return maintenance and the operating time B1 of the circulation means in the second intermittent maintenance is A1≦B1, and the inkjet recording apparatus according to claim 8 or claim 14, characterized in that.

17. The relationship between the operating time A2 of the stirring means in the pre-return maintenance and the operating time B2 of the stirring means in the second intermittent maintenance is A2≦B2, and the inkjet recording apparatus according to claim 14 or claim 15, characterized in that.

18. The control means starts the ink agitation by the agitation means either simultaneously with or prior to the ink circulation by the circulation means. The inkjet recording apparatus according to any one of claims 12 to 14, characterized in that.

19. When the acquisition means cannot acquire the return time before shifting to the first state, The control means, After shifting to the first state, the first intermittent maintenance including ink circulation by the circulation means and ink agitation by the agitation means is executed at a predetermined time interval, The relationship between the ratio X1 of the operating time to the non-operating time of the circulation means in the first intermittent maintenance and the ratio X2 of the operating time to the non-operating time of the agitation means in the first intermittent maintenance is X1 ≦ X2 The inkjet recording apparatus according to claim 13, characterized in that.

20. The control means, In the first intermittent maintenance or the second intermittent maintenance, controls the recording head so as not to eject ink The inkjet recording apparatus according to claim 11 or claim 15, characterized in that.

21. The recording head is capable of ejecting a plurality of types of ink, The control means independently determines the processing content of the pre-return maintenance for each of the plurality of types of ink The inkjet recording apparatus according to claim 1, characterized in that.

22. When a print job is input before the return time is reached, the control means starts the recording operation according to the print job at the time when the pre-return maintenance for the ink used in the print job is completed The inkjet recording apparatus according to claim 21, characterized in that.

23. The inkjet recording apparatus according to claim 1, characterized in that the ink contains white ink.

24. The inkjet recording apparatus according to claim 1, characterized in that the ink contains metallic ink.

25. A recording head that performs a recording operation of ejecting ink to record an image, A control method for an inkjet recording apparatus, comprising: a circulation means that supplies ink from a tank to the recording head and returns the ink recovered from the recording head to the tank for circulation, A step of acquiring a return time, which is a time of returning from a first state in which the recording operation is paused to a second state in which the recording operation is executable After transitioning to the first state, performing pre-return maintenance including ink circulation so that the pre-return maintenance is completed before the return time; A control method characterized by including the above.

26. A recording head that performs a recording operation of discharging ink to record an image; A program for causing a computer to execute a control method for an inkjet recording apparatus including a circulation unit that supplies ink from a tank to the recording head and returns the ink recovered from the recording head to the tank for circulation, the program comprising: Obtaining a return time which is a time to return from a first state in which the recording operation is paused to a second state in which the recording operation is executable; After transitioning to the first state, performing pre-return maintenance including ink circulation so that the pre-return maintenance is completed before the return time; A program including the above.

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