JP2024006675A - Recording apparatus and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent mixed color ink and foreign substances from intruding into a fluid channel during recovery operation, while suppressing reduction in productivity.

SOLUTION: A recording apparatus comprises: a recording head with a discharge port for discharging ink; driving means for applying drive to move ink in the recording head so as to pass through the discharge port; recovery means for performing recovery operation of the recording head after recording operation by the recording head; and control means for controlling execution timing of the recovery operation by the recovery means. In the case of performing recording operation using the recording head while moving ink according to drive of the driving means, the control means stops the driving means before the recording operation terminates.

SELECTED DRAWING: Figure 10

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a recovery operation in a recording device.

In an inkjet recording device, an increase in the viscosity of the ink inside the ejection ports is prevented by circulating the ink through a flow path that communicates with each of the ejection ports arranged in high density and a pressure chamber corresponding to the ejection ports. A configuration for suppressing this is known (Patent Document 1). In Patent Document 1, a pressure difference between two pressure adjustment mechanisms is used to cause ink to flow through a pressure chamber.

In addition, in an inkjet recording apparatus, a recovery operation is generally performed by wiping the ejection port array surface of the recording head with a wiper blade or the like. At this time, so-called color mixing may occur in which ink adhering to the ejection port arrangement surface enters the ejection ports and mixes, or foreign matter may be pushed into the ejection ports. Typically, such mixed colors and foreign matter are removed by a pre-discharge or suction operation.

Here, in a configuration in which ink within the ejection ports is circulated as in Patent Document 1, if the recovery operation of the ejection port array surface is performed while the ink within the ejection ports is being circulated, the mixed color ink and foreign matter within the ejection ports will be transferred to the circulation flow path. It may penetrate deep into the body and become impossible to remove. Patent Document 2 describes a configuration in which a circulation pump is stopped when performing a recovery operation on a discharge port array surface.

Japanese Patent Application Publication No. 2017-124617 Japanese Patent Application Publication No. 2016-199021

However, even if the circulation pump is stopped when performing the recovery operation as in Patent Document 2, a time lag may occur until the flow velocity of ink passing through the ejection ports completely stops. For example, when the ink flow is caused by the pressure difference between the pressure adjustment mechanisms as in Patent Document 1, the ink flow may occur in the circulation channel including the ejection port until the pressure difference is eliminated. For this reason, for example, when the circulation drive is stopped after the recording operation is completed and the ejection port array surface is recovered, if the time from the end of the recording operation to the start of the recovery operation is short, the circulation flow velocity within the ejection ports remains unchanged. A recovery action will be performed. In that case, the mixed color ink or foreign matter may enter deep into the flow path due to the circulating flow velocity, and may not be removed by preliminary ejection or suction operation. As a result, there is a possibility that abnormalities in the color tone of the recorded image, misplacement of landing of ink droplets, and non-ejecting nozzles may occur.

On the other hand, if the circulation drive is stopped after the recording operation is completed and a waiting time is provided until the circulation flow velocity stops, the start of the recovery operation will be delayed as a result, which may lead to a decrease in productivity.

An object of the present disclosure is to suppress mixing of color mixed ink or foreign matter into a flow path during a recovery operation while suppressing a decrease in productivity.

A recording apparatus according to an aspect of the present disclosure includes a recording head having an ejection port for ejecting ink, a driving unit for driving ink in the print head to pass through the ejection port, and a drive unit configured to drive the ink in the print head so as to pass through the ejection port. A recording apparatus comprising a recovery means for performing a recovery operation of the recording head after a recording operation, and a control means for controlling the execution timing of the recovery operation by the recovery means, wherein the control means is configured to perform a recovery operation by the drive means. When a recording operation is performed using the recording head while moving ink by driving, the driving means is stopped before the recording operation is completed.

According to the present disclosure, it is possible to suppress the mixing of mixed color ink or foreign matter into the flow path during the recovery operation while suppressing a decrease in productivity.

1 is a diagram showing the appearance of a recording device. FIG. 2 is a block diagram showing the configuration of a recording control system in the recording apparatus. FIG. 3 is a diagram illustrating the configuration of a recording head. FIG. 3 is a schematic diagram of a recovery unit. FIG. 2 is a diagram schematically showing the configuration of a recording head. FIG. 3 is a diagram showing the configuration of an ejection port and a flow path, and the flow of ink. FIG. 3 is a schematic diagram of the bottom surface of the chip. It is a graph showing the relationship between circulation flow rate and elapsed time. FIG. 3 is a diagram showing time changes in circulation flow velocity and operation of a recording device. 7 is a flowchart for determining the timing to stop circulation drive during a recording operation. It is a table showing an example of required flow velocity. It is a figure showing a flow velocity prediction table. It is a graph showing circulation flow velocity and elapsed time. 7 is a flowchart for determining the timing to stop circulation drive during a recording operation. FIG. 3 is a diagram illustrating an example of a flowchart for determining whether a recovery operation can be performed. FIG. 7 is a diagram showing a table in which allowable values are set for each ink color and type of recovery operation. FIG. 6 is a diagram showing execution timing at which a recovery operation is executed.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the matters disclosed herein, and not all combinations of features described in the embodiments are essential to the solution means of the present disclosure. Note that the same reference numbers are given to the same components.

In this specification, the term "record" refers not only to the formation of significant information such as characters and figures, but also to any meaningful or non-significant information. Furthermore, "recording" broadly refers to the formation of images, patterns, patterns, etc. on recording media, or the processing of media, regardless of whether or not they have been visualized so that humans can perceive them visually. It shall also represent the case. "Recording medium" refers not only to paper used in general recording devices, but also to a wide range of materials that can accept ink, such as cloth, plastic films, metal plates, glass, ceramics, wood, and leather. do. "Ink" (sometimes referred to as "liquid") should be broadly interpreted as in the definition of "recording" above. Therefore, by being applied onto a recording medium, it is possible to form images, patterns, patterns, etc., process the recording medium, or process the ink (for example, solidify or insolubilize the coloring material in the ink applied to the recording medium). represents a liquid that can be served. Unless otherwise specified, the term "nozzle" refers to an ejection opening, a liquid path communicating with the ejection opening, and an element that generates energy used for ink ejection.

2. Description of the Related Art In order to improve image quality and durability, resins and the like are generally added to inks used in inkjet recording devices. The addition of resins, etc. increases the viscosity of the ink as water evaporates, so the coloring material stays on the recording medium to improve color development, or it protects the coloring material with a resin film to improve fastness. This is done to improve the quality of life. Here, when disposing ejection ports at a high density to eject smaller droplets in order to improve image quality, ink thickening may occur within the ejection ports due to water evaporation. As a result, the ejection of ink droplets may be obstructed, and the landing positions of ink droplets on the recording medium may be disturbed or non-ejection may occur, resulting in a loss of image quality.

The inkjet recording apparatus of this embodiment suppresses thickening of the ink inside the ejection ports by circulating the ink so as to pass through the ejection ports. In the following, an example of suppressing mixed color ink or foreign matter from entering the flow path during a recovery operation while suppressing a decrease in productivity in such an inkjet recording apparatus will be specifically described.

<<First embodiment>>
<Configuration of recording device>
FIG. 1 is a diagram showing the appearance of an inkjet recording apparatus (hereinafter also simply referred to as a recording apparatus) according to this embodiment. The recording apparatus 101 of this embodiment is a so-called serial scanning printer, and scans the recording head 110 in the X direction (scanning direction) perpendicular to the Y direction (transportation direction) in which the recording medium 103 is transported. It records images.

The configuration of the recording apparatus 101 and its operation during recording will be outlined using FIG. 1. First, the recording medium 103 is conveyed in the Y direction from the spool 106 holding the recording medium 103 by a conveyance roller driven by a conveyance motor 204 (FIG. 2) via a gear. The fed recording medium 103 is conveyed while being held between a paper feed roller and a pinch roller, and guided to a recording position (a scanning area of the recording head 110) on the platen 104. On the other hand, at a predetermined transport position, the carriage motor 205 (FIG. 2) causes the carriage unit 102 to reciprocate (reciprocate) in the X direction along the guide shaft 108 extending in the X direction. A recording head 110 is mounted on the carriage unit 102. During this scanning process, the nozzles (ejection ports) of the recording head 110 are caused to eject at a timing based on the position signal obtained by the encoder 107, and a constant band width corresponding to the array range of the ejection ports is ejected. A recording is made. Thereafter, the recording medium 103 is transported, and recording of the next band width is performed. In this way, a desired image is recorded on the recording medium 103 by alternately carrying out the conveyance of the recording medium 103 and performing recording scanning by the recording head 110.

Note that, normally, in the rest state, the face surface of the recording head 110 is capped by a cap 211 provided in a recovery unit 210 (FIG. 4), which will be described later. For this reason, prior to printing, the cap 211 is opened to put the print head 110 (carriage unit 102) into a scannable state. Thereafter, when data for one scan is accumulated in the buffer, the carriage motor 205 causes the carriage unit 102 to scan, and the above-described recording operation is performed.

Note that a carriage belt (not shown) can be used to transmit the driving force from the carriage motor 205 to the carriage unit 102. However, instead of the carriage belt, for example, one may be provided with a lead screw that is rotationally driven by the carriage motor 205 and extends in the X direction, and an engaging portion that is provided on the carriage unit 102 and that engages with the groove of the lead screw. may also be used. In this way, it is also possible to use other drive methods.

Further, ink to be supplied to the recording head 110 is supplied from an ink tank 202 (FIG. 5) inside the main body of the recording apparatus 101 or mounted on an external unit via a supply tube 105 via the carriage unit 102. Ink may be supplied from the ink tank 202 to the recording head 110 using a pressure unit. Alternatively, the ink may be supplied by capping the ejection port surface of the recording head 110 using the cap 211 of the recovery unit 210 and applying negative pressure inside the cap with a suction pump 213 (FIG. 4) to suck it.

A plurality of recording heads 110 capable of ejecting one or more colors of ink may be mounted on the carriage unit 102, or one recording head 110 capable of ejecting multiple colors of ink may be mounted on the carriage unit 102. It may also be in the form of being mounted. Alternatively, one or more recording heads 110 capable of ejecting ink of a single color may be mounted on the carriage unit 102.

<Recording control>
FIG. 2 is a block diagram showing the configuration of a printing control system in the printing apparatus 101 shown in FIG.

The recording device 101 is connected to a data supply device such as a host computer (hereinafter referred to as host PC) 306 via an interface 307 . Various data or control signals related to recording transmitted from the host PC 306 are input to the recording control unit 301 of the recording apparatus 101. The recording control unit 301 includes a memory 303 that stores input image data, multi-level gradation data of an intermediate product, and a multi-pass mask, and a CPU 302 (which may be an ASIC) that is a control calculation device. The recording control unit 301 also includes an image processing unit 304 that performs various types of image processing, and a data processing unit 305 that performs various types of data processing. The processing by the image processing unit 304 and the data processing unit 305 may be executed by the CPU 302. The recording control unit 301 controls a motor driver and a head driver, which will be described later, according to a control signal input via an interface 307.

The conveyance motor 204 is a motor that rotationally drives a conveyance roller for conveying the recording medium 103. The carriage motor 205 is a motor that reciprocates the carriage unit 102 on which the recording head 110 is mounted. The recovery unit motor 206 is a motor mounted on the recovery unit 210, and switches the units driven by the camshaft to operate the wiper guide 223 and the suction pump 213 (FIG. 4). Motor drivers 308, 309, and 310 are drivers that rotationally drive the transport motor 204, carriage motor 205, and recovery unit motor 206, respectively. The head driver 311 is a driver that drives the recording head 110, and when a plurality of recording heads are mounted, a plurality of head drivers 311 are provided corresponding to the number of recording heads.

<Recording head configuration>
FIG. 3 is a diagram illustrating the configuration of the recording head 110 in this embodiment. FIG. 3 is a diagram showing an example of the configuration of the recording head 110 and the ejection port group. The recording head 110 in this embodiment includes independent buffer tanks 401C, 401M, 401Y, and 401BK that correspond to four color inks: cyan, magenta, yellow, and black. Although the buffer tank is shown in FIG. 3 so as to be visible for the sake of explanation, the buffer tank is stored inside the recording head 110. On the lower surface (+Z direction) of the recording head 110, a chip 403 is arranged, in which ejection port arrays corresponding to each ink are formed. On the chip 403, 1024 ejection ports 402 are formed in two rows at intervals of 1200 dpi per color, making it possible to eject two colors with one chip. By arranging two such chips 403, recording in four colors is possible. Note that the ejection port rows for one color do not need to be arranged on the same straight line, but may be arranged alternately one by one, and a total of 4 rows of 512 ejection port rows are arranged at an interval of 600 dpi.

<Recovery unit>
FIG. 4 is a schematic diagram of the recovery unit 210 according to this embodiment. The recovery unit 210 includes a cap 211 that covers the ejection port surface of the print head 110, and a suction pump 213 that sucks ink from the print head 110 while the cap 211 covers the ejection port surface. The recovery unit 210 also includes a first wiper 221 and a second wiper 222 that wipe the ejection port surface of the recording head 110. The recovery unit 210 is arranged outside the recording area in the moving direction (X direction) of the carriage unit 102. The carriage unit 102 stops at a standby position outside the recording area as necessary before and during the recording operation. The recovery unit 210 is arranged at a position facing the recording head 110 when the carriage unit 102 is stopped at the standby position.

The cap 211 is supported so as to be able to rise and fall by a lift mechanism (not shown), and moves between a raised position and a lowered position. In the raised position, the cap 211 contacts the recording head 110 and covers (caps) the ejection port surface of the recording head 110. By covering the ejection port surface of the print head 110, the cap 211 can prevent the ejection port 402 of the print head from drying and ink from evaporating during non-printing operations. Further, the cap 211 can suck ink from the recording head 110 by driving a suction pump 213, which will be described later. Furthermore, during the recording operation, the cap 211 is located at a lowered position to avoid interference with the recording head 110 that moves together with the carriage unit 102. With the cap 211 in the lowered position, the recording head 110 can perform preliminary ejection to the cap 211 when moved to a position facing the cap 211.

The first wiper (wiper blade) 221 and the second wiper (wiper blade) 222 are made of an elastic member such as rubber. In this embodiment, two first wipers 221 each wipe the ejection port surface of two chips 403 in FIG. 2, and a second wiper 222 wipes the entire ejection port surface including the ejection port array. There is. The first wiper 221 and the second wiper 222 are fixed to the wiper holder 220. The wiper holder 220 is movable along the wiper guide 223 in the front-rear direction in the figure indicated by the arrow W (the arrangement direction of the ejection ports in the recording head, ie, the Y direction). When the recording head 110 is located at the standby position, the wiper holder 220 moves in the direction of arrow W (one direction), so that the first wiper 221 and the second wiper 222 wipe the ejection port surface while coming into contact with the ejection port surface. A wiping operation can be performed. When the wiping operation is completed, the carriage unit 102 is moved and evacuated from the area where the wiping operation is performed, and then the wiper holder 220 is moved to return the first wiper 221 and the second wiper 222 to their original positions (positions before the wiping operation). Return to

Note that although this embodiment will be described using an example having the first wiper 221 and the second wiper 222, a configuration having only one of the wipers may be used. Further, in this embodiment, an example will be described in which the wiper is made of an elastic member such as rubber, but it may be a member made of a porous material that absorbs ink. Further, the wiper may be configured as a vacuum wiper capable of sucking the discharge port surface. Further, in the present embodiment, an example will be described in which wiping is performed only when the wiper moves in one direction, but a configuration may be adopted in which wiping is performed when the wiper moves in both directions. In addition, in this embodiment, an example will be explained in which the wiping direction is the arrangement direction of the ejection ports in the print head (Y direction), but the direction intersecting (orthogonal to) this direction (the arrangement direction of the ejection port array, the X direction) It may be configured to move to. Further, in this configuration, the wiper may be fixed and the discharge port surface may be wiped by moving the carriage unit 102 in the scanning direction. Alternatively, the wiper may be configured to wipe by moving in both the X direction and the Y direction. Further, in a configuration in which wiping is performed using a plurality of wiping members or different wiping directions, the recovery units may be arranged at separate positions. In that case, the recovery unit 210 may be divided and arranged near the standby position of the carriage unit 102 and on the opposite side across the recording medium.

The suction pump 213 is driven in a state where the cap 211 covers the ejection port surface of the recording head 110 and makes the inside thereof a substantially sealed space. Thereby, by generating negative pressure inside the cap 211, a suction operation for sucking ink from the recording head 110 is performed. This suction operation is performed when filling ink into the recording head 110 from the ink tank 202 (initial filling), or when removing dust, stuck objects, air bubbles, etc. inside the ejection port by suction (during suction recovery), etc. It will be held on. The cap 211 is connected to a waste ink absorber (not shown) via a flexible tube 212.

In this embodiment, a tube pump is used as the suction pump 213. The tube pump includes a holding part formed with a curved surface part that holds at least a part of the tube 212 along, a roller that can press the held tube 212, and a roller support part that rotatably supports the roller. have The tube pump rotates the roller while crushing the tube 212 by rotating the roller support portion in a predetermined direction. This generates negative pressure inside the cap 211 and sucks ink from the recording head 110. The sucked ink is discharged to the waste ink absorber through the tube 212. The suction operation is also performed when the recording head 110 performs preliminary ejection onto the cap 211 and when the ink received in the cap 211 due to the preliminary ejection is discharged. That is, by driving the suction pump 213 when the preliminary ejected ink held in the cap 211 reaches a predetermined amount, the ink held in the cap 211 is transferred to the waste ink absorber through the tube 212. can be discharged.

In this manner, the recovery unit 210 performs a recovery operation to restore the discharge port surface to a normal state. The recovery operation may also be referred to as a cleaning operation or cleaning operation. Further, the recovery unit 210 may be referred to as a maintenance unit that performs maintenance on the discharge port surface.

<Ink circulation>
FIG. 5 is a diagram schematically showing the configuration of the recording head 110. This is a schematic diagram of a flow path for one color. In this embodiment, as described above, it is assumed that buffer tanks and flow paths for four colors, cyan, magenta, yellow, and black, are configured in one recording head 110. A supply tube 105 connected to the ink tank 202 is connected to a joint 404 of the head body 120 through the inside of the carriage unit 102, and is communicated with the buffer tank 401. The supplied ink passes through the filter 405 and the flow path within the buffer tank 401 to reach the first pressure control member 406 . The first pressure control member 406 is connected to a second pressure control member 407, which is another pressure control member, via a flow path, and is connected to the second pressure control member 407 via a circulation drive pump 408 in another flow path. 407.

A valve 411 that opens when a predetermined negative pressure is reached is provided at the inlet of the first pressure control member 406. A valve 412 that opens when a predetermined negative pressure is reached is provided at the inlet of the second pressure control member 407. The inlet of the first pressure control member 406 is provided in the flow path between the first pressure control member 406 and the filter 405. The inlet of the second pressure control member 407 is provided in the flow path between the second pressure control member 407 and the first pressure control member 406. The negative pressure at which the valve 412 at the inlet of the second pressure control member 407 opens is configured to be higher than the negative pressure at which the valve 411 of the first pressure control member 406 opens.

Ink is supplied from the first pressure control member 406 into the chip 403 via a common supply channel 409 configured within the head main body 120 . Specifically, ink is supplied from the common supply channel 409 to supply channels (described later) of one or more ejection port arrays arranged in the chip 403. Then, ink is ejected from the ejection port 402. Further, ink that is not ejected is collected into the buffer tank 401 via the ejection port 402. That is, the ink that has passed through the ejection port 402 passes from a recovery channel (described later) in the chip 403 to a common recovery channel 410 configured in the head body 120 and is recovered by the second pressure control member 407 .

FIG. 6 is a diagram showing the configuration of the ejection port 402 and the flow path formed in the chip 403, and the flow of ink. FIG. 7 is a schematic diagram of the bottom surface of the chip 403 (the surface on which the ejection port 402 is arranged). The configuration of the ejection ports 402 and flow paths formed in the chip 403 and the flow of ink will be described below with reference to FIGS. 6 and 7. A discharge port 402 is formed in an orifice plate 420 on the surface of the chip 403. At a position (pressure chamber) corresponding to the ejection port 402 on the substrate 430, an ejection energy generating element 423 that generates ejection energy for ejecting ink is provided. That is, a discharge energy generating element 423 is provided corresponding to each of the discharge ports 402. As the ejection energy generating element 423, an electrothermal conversion element (heater), a piezoelectric element, or the like can be used. When a heater is used, the heat generated by the heater causes the ink in the ejection port 402 to bubble, and the bubbling energy can be used to eject the ink from the ejection port 402.

When the chip 403 is supplied with ink, it is maintained at a negative pressure such that a meniscus is formed on the ejection port surface. Two flow paths, an inflow port 421 and an outflow port 422, are formed on both sides of the discharge port 402, respectively. In this embodiment, the inlet 421 and the outlet 422 are arranged so that one corresponds to each of the two discharge ports 402, as shown in FIG. Note that the number of inflow ports 421 and outflow ports 422 may be one per each discharge port 402. One outlet may be arranged for each outlet 402 in number greater than two. Furthermore, the numbers of inflow ports 421 and outflow ports 422 do not need to match. As shown in FIG. 6, the inlet port 421 and the outlet port 422 are connected to a supply channel 431 and a recovery channel 432, respectively, which are formed along the discharge port array direction (Y direction). The supply channel 431 and the recovery channel 432 are covered with a cover plate 440 and are connected to the common supply channel 409 and the common recovery channel 410 of the head body 120 via an opening 441 on the cover plate. . One or more openings 441 are provided in each of the supply channel 431 and the recovery channel 432. Note that the number of openings 441 may be the same or different in the supply channel and the recovery channel.

Next, with reference to FIG. 5, a method of supplying ink to the print head 110 and buffer tank 401 and a method of circulating ink within the ejection ports in this embodiment will be described. The ink is pressurized from the ink tank 202 and reaches the recording head 110 via the supply tube 105, passes through the filter 405, and enters the ink in front of the valve 411 disposed at the inlet of the first pressure control member 406. It flows into the flow path. When the recording head is filled with ink at an appropriate negative pressure so that a meniscus is maintained on the ejection port surface, the valve 411 disposed at the inlet of the first pressure control member 406 is closed. , no ink flows into the first pressure control member 406 . On the other hand, when a strong negative pressure is applied to the ejection port 402 due to the suction operation using the cap 211 of the recovery unit 210, or when ink is ejected from the ejection port 402, the first pressure control member 406 becomes negative. When the pressure increases, the inlet valve 411 opens. Ink then flows into the first pressure control member 406 .

As shown in FIG. 5, the first pressure control member 406 and the second pressure control member 407 are connected to a circulation drive pump 408. When the circulation drive pump 408 is driven, ink is transferred from the second pressure control member 407 to the first pressure control member 406 via the circulation drive pump 408 . As a result, the negative pressure of the second pressure control member 407 increases, and the valve 412 at the inlet of the second pressure control member 407 opens, causing ink to flow from the first pressure control member 406 to the second pressure control member 407. be returned. Further, at this time, since a pressure difference is generated between the first pressure control member 406 and the second pressure control member 407, a flow of ink passing through the ejection port 402 is generated. That is, ink passes through the channels in this order from the first pressure control member 406 to the common supply channel 409, the opening 441 of the cover plate 440, the supply channel 431 of each ejection port array, and the inlet 421, and enters the ejection port 402. Some ink flows. Furthermore, ink passes through the flow channels in this order from the discharge port 402 to the outlet 422, the recovery channel 432, the opening 441 of the cover plate 440, and the common recovery channel 410, and is recovered by the second pressure control member 407. That is, the ink inside the chip 403 flows in the direction of the arrow shown in FIGS. 5 and 6. Note that the negative pressure within the ejection port 402 and the ink flow rate are adjusted to be within a range that can maintain the meniscus. That is, by adjusting the flow rate of the circulation drive pump 408, the pressure loss in the flow path between the first pressure control member 406 and the second pressure control member 407, and the opening/closing force of the inlet valve, the inside of the discharge port 402 can be adjusted. The negative pressure and ink flow rate are adjusted.

As described above, by driving the circulation drive pump 408, a flow is generated in which the ink near the ejection port 402 moves, suppressing an increase in ink viscosity due to drying inside the ejection port during printing operation, and deteriorating the ink ejection characteristics. can be suppressed.

<Recovery operation control process>
In this embodiment, a method for determining the timing to stop circulation drive will be described when ink is circulated in a flow path passing through an ejection port during a printing operation and a recovery operation of the ejection port surface is performed after the printing operation is completed. By stopping the circulation drive before the end of the recording operation, that is, at an appropriate timing during the recording operation, it is possible to reduce the time spent waiting for the start of the recovery operation while suppressing the influence on the recorded image.

FIG. 8 is a graph showing the relationship between circulation flow rate and elapsed time. FIG. 8 is a graph showing the ink flow velocity in the circulation channel passing through the ejection ports 402 from during the printing operation until the recovery operation of the ejection port surface is performed after the printing operation is completed. As described above, during the printing operation, the circulation drive pump 408 is driven to stabilize the ejection characteristics by circulating the ink within the ejection ports. Thereby, ink is circulated within the circulation channel.

Here, it is assumed that no ink is ejected from the ejection ports 402 during the printing operation in FIG. Therefore, a constant pressure difference is generated between the first pressure control member 406 and the second pressure control member 407, and the flow rate of the ink is also constant. Note that when ink is ejected, the negative pressure of the first pressure control member 406 and the second pressure control member 407 temporarily increases, and the pressure difference also changes. However, when the valve 411 at the inlet of the first pressure control member 406 opens and ink is supplied from the ink tank 202 to the buffer tank 401, the original pressure state is restored. In this way, a temporary change in pressure difference may occur during the printing operation, but in this embodiment, for the sake of simple explanation, no ink is ejected from the ejection ports 402, and the ink is not ejected during the printing operation. The explanation will be made assuming that the flow velocity is constant.

When the recording operation is finished, the recording head 110 returns to the standby position, performs a necessary recovery operation by the recovery unit 210, and is then capped. In FIG. 8, the preliminary operation includes an initialization operation in which the recording head 110 returns to the standby position and the wipers (including the first wiper 221 and the second wiper 222) of the recovery unit 210 are moved to the wiping start position. An example of wiping with a wiper after the preliminary operation is described.

After the printing operation is completed, there is no need to circulate the ink within the ejection ports 402 to suppress the increase in viscosity due to evaporation. Therefore, in FIG. 8, the recording control unit 301 stops driving the circulation drive pump 408 at the timing when the recording operation ends. However, immediately after the circulation flow rate of ink due to pump drive stops, a pressure difference remains between the first pressure control member 406 and the second pressure control member 407. Therefore, since the valve 412 at the inlet of the second pressure control member 407 is open, ink continues to flow for a certain period of time in the flow path between the pressure chambers and the flow path passing through the discharge port. . The pressure difference between the first pressure control member 406 and the second pressure control member 407 is gradually eliminated as the ink flows. Therefore, as time passes, the valve 412 closes, and the ink further flows through the ejection port 402, and the flow rate of the ink slows accordingly, and after a certain period of time, the circulation almost stops.

Here, if the time from the above-mentioned circulation drive stop to the time when the circulating flow velocity stops is longer than the time from when the circulating flow velocity starts to wiping, wiping is performed while the circulating flow velocity is stopped. Therefore, even if wiping is started, mixed color ink and foreign matter can be prevented from entering deep into the circulation flow path. On the other hand, as shown in FIG. 8, if the time from the stop of the circulation drive to the start of wiping is shorter than the time from the stop of the circulation drive to the stop of the circulation flow velocity, wiping will be performed before the circulation flow velocity has stopped. It turns out. As a result, mixed color ink and foreign matter enter deep into the circulation flow path. In order to prevent the mixed color ink and foreign matter from entering deep into the circulation flow path, wiping is started after waiting until the circulation flow rate stops.

FIG. 9 is a diagram showing temporal changes in circulation flow velocity and operation of the recording device. FIG. 9(a) shows the time change in the circulation flow velocity and the operation of the recording device, which can be applied when the time from the stop of the circulation drive to the start of wiping is shorter than the time from the stop of the circulation drive to the stop of the circulation flow velocity. There is. In FIG. 9(a), a wait time is provided for waiting for the flow velocity to stop. This wait time is a predetermined time added to the preliminary operation described above. As shown in FIG. 9(a), due to the wait time provided in this way, the start of the wiping operation is delayed compared to the case of FIG. 8. Therefore, due to the delay in wiping, the start of the recording operation for the next recorded image is also delayed. Therefore, the productivity of the recording apparatus decreases.

Furthermore, in order to avoid such a decrease in productivity, it is conceivable to stop the circulation drive pump 408 during the recording operation, thereby stopping the ink flow velocity in the circulation flow path at the time when wiping is started. FIG. 9(b) is a diagram showing the temporal change in the circulating flow velocity and the operation of the recording device in this case. Since the circulation drive pump 408 is stopped during the printing operation, the flow velocity of the ink in the ejection port 402 decreases until the printing operation ends. Here, during the time indicated by the shaded area in FIG. 9B, where the circulating flow velocity is slower than the flow velocity V1 required to maintain the ejection characteristics, there is a possibility that the ejection characteristics may deteriorate due to an increase in viscosity due to ink evaporation. As a result, the landing position may be disturbed, resulting in a decrease in image quality, or a non-ejecting nozzle may occur, resulting in image defects.

Therefore, in this embodiment, by stopping the circulation drive pump 408 at an appropriate timing during the recording operation, the flow velocity in the circulation flow path is maintained at an allowable level at the time when the recovery operation (also referred to as the cleaning operation) is started. An example of control will be explained.

FIG. 10 is a flowchart for determining the timing to stop the circulation drive during the recording operation in this embodiment. That is, FIG. 10 is a diagram showing a flowchart for determining the stop timing of the circulation drive pump 408 during the recording operation. Note that the processing shown in FIG. 10 is performed under the control of the recording control unit 301 by the CPU 302 executing a program stored in the memory 303 or the like. In this embodiment, the cyclic drive stop timing is determined including during the recording operation. Therefore, the process shown in FIG. 10 is a process that is repeatedly executed at predetermined timing during the recording operation. Note that the symbol "S" in the description of each process means a step in the flowchart (the same applies to other flowcharts described in this specification).

First, in S1001, the recording control unit 301 calculates the remaining time T1 of the recording operation at this point. In this embodiment, since an image is formed by serial scanning, the remaining number of scans is calculated from the unrecorded area of image data and the number of passes of multi-pass printing. Then, it is possible to calculate the remaining time T1 of the recording operation based on the remaining number of scans, the scanning speed and acceleration of the carriage, and the like.

Subsequently, in S1002, the recording control unit 301 determines whether to perform a recovery operation after the recording operation is completed. In this embodiment, a wiping operation for wiping the discharge port surface is performed as a recovery operation. Note that wiping may be performed using a plurality of first wipers 221, a second wiper 222, or both. In either case, the time required for pre-operation is known. If it is determined that the recovery operation is not to be performed after the end of the recording operation, the process advances to S1003, where the recording control unit 301 continues the cyclic drive and ends the cyclic drive stop determination flow at this timing. Thereafter, as described above, the process in FIG. 10 is performed again at a predetermined timing. Note that until the recording operation is completed, the result of the recovery operation execution determination may change depending on the timing at which the determination is performed. For example, when controlling to determine whether or not to perform a recovery operation according to the amount of ink ejected from the print head 110 and the passage of time, there is a possibility that the determination threshold value will be exceeded during the print operation. As mentioned above, the process in FIG. 10 is a process that is repeatedly executed at predetermined timing during the recording operation, so if the process in FIG. 10 is executed before or after the determination threshold is exceeded, the determination result in S1002 will change. It turns out. Therefore, in this embodiment, regardless of the determination result in S1002, the process in FIG. 10 is repeatedly performed until the recording operation is completed (that is, until the circulation drive operation is stopped).

If it is determined in S1002 that a recovery operation is to be performed after the recording operation ends, the process advances to S1004. The processing from S1004 to S1008 is repeated for each ink color. In S1004, the recording control unit 301 obtains a time T2 during which the ejection characteristics can be maintained when the circulation drive is stopped. In other words, the time T2 is a time that can be recorded without impairing the ejection characteristics from the circulation drive stop timing. In S1004, the recording control unit 301 calculates the time T2 as follows. First, the required flow velocity V1 changes depending on the type of ink, the recording operation mode, etc. The required flow velocity V1 is a flow velocity at which the ejection characteristics are maintained depending on the type of ink and the recording operation mode.

FIG. 11 is a table showing examples of required flow velocities corresponding to ink types and recording operation modes. The required flow rate is set for each type of ink because the degree to which the ejection characteristics deteriorate when evaporation of ink near the ejection port progresses varies depending on the type of ink. Further, a required flow velocity is provided depending on the recording operation mode. For example, it is necessary to suppress image quality deterioration more in high image quality mode. In addition, in high image quality mode, the number of printing passes increases and the frequency of ejection per ejection port decreases, so the time required for the ejection characteristics of the ejection port to recover due to ejection increases, resulting in image deterioration. stand out. For this reason, the required flow velocity is set faster in the high image quality mode than in other recording modes. The table shown in FIG. 11 is stored in advance in, for example, the memory 303.

In S1004, the recording control unit 301 first obtains the value of the required flow velocity V1 of the target ink color from the required flow velocity table shown in FIG. For example, if the ink to be determined this time is cyan (C) and the printing operation is in the standard image quality mode, the table in FIG. 11 is referred to and a flow velocity of 3 mm/s is obtained as the required flow velocity V1.

FIG. 12 is a diagram showing a flow velocity prediction table. FIG. 12 shows the predicted circulation flow velocity according to the elapsed time after the circulation drive was stopped. In FIG. 12, for example, in the case of cyan, when the current circulation flow velocity is 11.8 mm/s, and for example, 5 seconds have passed after stopping the circulation drive, the predicted value of the circulation flow velocity is 7.4 mm/s. It shows that. Although a single type of table is shown here as an example, processing is performed by appropriately referring to a table corresponding to the current circulating flow velocity. For example, in this embodiment, since the pressure difference is configured to be constant, the current circulation flow rate may also change depending on the viscosity of the ink. Since the viscosity of ink changes depending on the temperature, it is preferable to store tables depending on the temperature in the memory 303. Furthermore, the predicted circulating flow velocity may be derived by interpolation as appropriate.

The recording control unit 301 that has acquired the required flow velocity V1 subsequently acquires the circulation flow velocity for the elapsed time from the stop of the circulation drive from the flow velocity prediction table shown in FIG. 12 in the process of S1004. Then, the time period during which the required flow velocity V1 can be maintained after the circulation drive is stopped is obtained. Specifically, in the table of FIG. 12, the time period during which the cyan ink maintains a flow rate of 3 mm/s or more, which is the required flow rate V1, after the circulation drive is stopped is 10 seconds. In other words, time T2 (cyan)=10 seconds. In this way, in S1004, the time T2 during which the ejection characteristics of the target ink can be maintained when the circulation drive is stopped is obtained.

Next, in S1005, the recording control unit 301 compares the remaining time T1 of the recording operation calculated in S1001 with the time T2 during which the ejection characteristics can be maintained when the circulation drive is stopped. If the time T1 is less than the time T2 (T1<T2), the process advances to S1007. If T1<T2, even if the circulation drive pump 408 is stopped at this point, the ejection characteristics will not be impaired until the end of the recording operation. Therefore, in S1007, the recording control unit 301 stops the circulation drive pump 408 that is circulating the target ink. As described above, since the time T2 differs depending on the ink, the determination is made for each ink, and each circulation drive pump 408 is stopped individually. Note that in the circulation path using the circulation drive pump 408 that has been stopped, the circulation drive pump 408 is stopped under the judgment that the ejection characteristics of the target ink will be maintained until the end of the printing operation. For this reason, for example, when the process of FIG. 10 is repeatedly executed, the type of recovery operation after the end of the recording operation changes, and it is determined that there is no need to stop the circulation drive pump 408. However, the pump shall be stopped immediately. That is, in the process of FIG. 10, the process once proceeds to S1007, and the ink whose driving circulation is stopped may be skipped from S1004 to S1007 in the process of FIG. 10, which is repeatedly executed at a predetermined timing thereafter. Alternatively, if the circulation drive of the target ink has already stopped when the process proceeds to S1007, the process of S1007 may be skipped. After S1007, the process advances to S1008. On the other hand, if it is determined in S1005 that the remaining time T1 of the recording operation is longer than the time T2 during which the ejection characteristics can be maintained when the circulation drive is stopped, the process advances to S1006. In S1006, the recording control unit 301 determines that the current processing timing in FIG. 10 is not the timing to stop the circulating drive of the target ink, and continues the circulating drive of the target ink. After S1006, the process advances to S1008.

In S1008, the recording control unit 301 determines whether processing for all inks has been completed. If there is unprocessed ink, the process returns to S1004 and the process is repeated. In other words, the process in FIG. 10 is repeatedly executed at a predetermined timing during the printing operation, and at the executed timing, all inks are processed. If it is determined that the processing for all inks has been completed, the processing advances to S1009.

In S1009, the recording control unit 301 determines whether the circulation drive of all inks has stopped. If all the ink circulation drives have stopped, the process advances to S1010. If the circulation drive of all the inks has not stopped, the process of FIG. 10 at this timing ends. Then, the process in FIG. 10 is repeated again at the next predetermined timing.

In S1010, the recording control unit 301 counts the time T3 from the timing when all circulation drives stop until the end of the recording operation. At the time of S1010, the recording operation is being executed. For this reason, counting is performed from the timing when the circulation drive of the last target ink is stopped in S1007, and the time T3 until the end of the printing operation is counted. That is, in S1010, time T3 continues to be counted until the recording operation is completed. This time T3 corresponds to a time period in which the stop timing of the circulation drive can be brought forward from the original stop timing of the circulation drive, which is the time when the recording operation is stopped. The circulation flow speed is stopped earlier by this time T3, and the timing of executing the wiping operation can be brought forward. That is, as shown in FIG. 9(a), after stopping the circulation drive, a preparatory operation time is provided, and a wait time is provided, and then wiping is started, and the time can be advanced by the time T3. That is, when performing the wiping operation, it is possible to exclude the time T3 from the wait time until the circulating flow velocity stops and perform the wiping operation.

FIG. 13 is a graph showing circulation flow rate and elapsed time. In FIG. 13, the timing of stopping the circulation drive is the timing during the recording operation. That is, in FIG. 9A, the circulation drive is stopped at the timing when the recording operation is completed, whereas in FIG. 13, the circulation drive is stopped during the recording operation. Furthermore, in FIG. 13, at the timing when the recording operation ends, the circulating flow velocity is maintained higher than the required flow velocity V1. In FIG. 13, wiping is started at a timing obtained by subtracting the time T3 from the stop of the circulation drive to the end of the recording operation from the wait time. In other words, it is possible to advance the wiping start timing by the time T3 while maintaining the ejection characteristics.

Note that here, the timing obtained by subtracting the time T3 from the wait time is set as the wiping start timing. This is because the preliminary operation time from the end of the recording operation to the wiping operation cannot be reduced. In other words, the preliminary operation time for moving the recording head 110 to the recovery operation position and preparing the recovery unit 210 after the recording operation is finished is necessary preparation time. Therefore, if the circulation flow rate stops during the preliminary operation, wiping is started without waiting time after the preliminary operation.

As described above, according to the present embodiment, it is possible to suppress the mixing of mixed color ink or foreign matter into the flow path during the recovery operation while suppressing a decrease in productivity. In this embodiment, the execution timing of the wiping operation is determined according to the timing at which the circulation drive pump 408 is stopped. That is, the timing at which the circulation drive of each ink is stopped is brought forward from the end of the printing operation within a range in which the circulating flow velocity during the printing operation does not become slower than the flow velocity V1 necessary to maintain the ejection characteristics. Further, in accordance with the advance of the timing to stop the circulation drive of each ink, the timing of starting wiping is brought forward. Thereby, it is possible to suppress a decrease in productivity, suppress the influence on the recorded image after the circulation drive is stopped, and suppress color mixing during wiping and intrusion of foreign substances into the flow path.

<<Second embodiment>>
In the first embodiment, an example has been described in which the recovery operation executed after the end of the recording operation is a fixed recovery operation. That is, an example in which wiping processing is performed using a single type of wiper member has been described. In the first embodiment, since a single type of recovery operation is used, the time required for the preliminary operation is also fixedly determined. For this reason, in the first embodiment, an example has been described in which the time required for the preliminary operation is set as a fixed time and the wait time exceeding the preliminary time is adjusted.

In this embodiment, an example will be described in which there are multiple types of recovery operations that may be executed after the recording operation is completed. Depending on the recovery operation, the pre-operation time may vary. Furthermore, the circulation flow rate allowed during the recovery operation may also change depending on the recovery operation. Therefore, in this embodiment, the timing to stop the circulation pump during the recording operation is determined based on the selected recovery operation. Furthermore, the execution timing of the recovery operation is determined based on the circulating flow velocity that is allowed when executing the selected recovery operation. Thereby, it is possible to advance the recovery operation execution timing and to suppress foreign matter from entering the circulation flow path due to the recovery operation of the discharge port surface. Moreover, even if foreign matter enters, it can be prevented from flowing deep into the circulation path by the circulation flow, making it possible to easily discharge the foreign matter through preliminary ejection.

FIG. 14 is a flowchart for determining the timing to stop the circulation drive during the recording operation in this embodiment. Similar to the process described in FIG. 10 of the first embodiment, the process in FIG. 14 is a process that is repeatedly performed at predetermined timing during the recording operation.

First, in S1401, the recording control unit 301 calculates the remaining recording operation time T1. The process in S1401 is the same as the process in S1001 in FIG. Then, in S1402, the recording control unit 301 determines whether to perform a recovery operation after the recording operation. The recovery operation in this embodiment includes various types of wiping operations such as a wiper blade, a nonwoven fabric, or a porous body. Further, the recovery operation includes various suction operations such as a suction recovery operation in which suction is performed while capping, and a vacuum wiper operation in which wiping is performed while suctioning. Then, the recovery operation is specified by a combination of these recovery operations, the number of times the recovery operation is performed, the selection of the recording head to be recovered, the preliminary ejection amount, and the like. If it is determined in S1402 that the recovery operation is not to be performed, the process advances to S1403, continues the circulation drive, and ends the process at this timing. On the other hand, if it is determined that the recovery operation is to be performed, the process advances to S1404. In S1404, the recording control unit 301 selects a recovery operation and sequence to be executed after the recording operation is completed.

Next, in S1405, the recording control unit 301 obtains a time T2 during which the ejection characteristics can be maintained when the circulation drive is stopped. This process is similar to the process described in S1004 of FIG. That is, the time T2 is obtained based on the required flow velocity table shown in FIGS. 11 and 12 and the predicted circulating flow velocity table for the elapsed time from the stop of circulation. Next, in S1406, the recording control unit 301 compares T1 and T2. If T1<T2, the process advances to step S1408, and the recording control unit 301 stops driving the ink circulation drive pump 408. These processes from S1405 to S1408 are similar to the processes from S1004 to S1007 of the first embodiment. In this embodiment, unlike the first embodiment, at the timing when the circulation drive pump 408 for the target ink is stopped in S1408, the recording control unit 301 starts counting the elapsed time T4 from the stop of circulation in S1409. This is because the preliminary operation before performing recovery may differ depending on the recovery operation sequence selected in S1402 described above. Further, depending on the selected recovery operation sequence, the position of the carriage unit 102 at the end of the recording operation may differ, or the ejection process or cutting operation of the recording medium may differ. These may change the timing at which the recovery operation is started. In other words, the time of the preliminary operation and the timing at which the recovery operation is started may change depending on the recovery operation. As described in the first embodiment, this circulation drive stop determination flow is repeatedly executed at a predetermined timing, and the recovery operation selected in S1404 may also change depending on the execution timing. In other words, if the recovery operation initially selected in S1404 during a recording operation exceeds a determination threshold or the like due to subsequent processing during the recording operation, another recovery operation may be selected in S1404 at a subsequent timing. could be. Therefore, by counting the time T4 from the circulation stop, it is possible to appropriately determine whether the recovery operation can be started in the recovery operation feasibility determination flow shown in FIG. 15, which will be described later. Furthermore, time T4 will be counted for each ink. Since the recovery operation timing may differ for each ink, it is counted individually. That is, in S1409, the time T4 for the ink whose circulation drive was stopped in S1408 is counted. After that, the process advances to S1410.

If T1<T2 is not satisfied in S1406, the process advances to S1407, and the recording control unit 301 continues to drive the target ink in circulation. The process then proceeds to S1410.

In S1410, the recording control unit 301 determines whether processing for all inks has been completed. If there is unprocessed target ink, the process returns to S1405 and repeats the process. When the processing for all inks is completed, the processing in FIG. 14 is ended. That is, when the circulation drive of all inks is stopped in the process of the circulation drive stop flow of FIG. 14, the time T4 for each ink continues to be counted.

FIG. 15 is a diagram illustrating an example of a flowchart for determining whether a recovery operation can be executed. The process in FIG. 15 is a process that is executed at the timing when the preliminary operation is completed and the recovery operation becomes executable. In other words, the circulation drive of the circulation drive pump 408 is stopped in the process of FIG. 14, after which the recording operation is completed, the preliminary operation performed with the completion of the recording operation is completed, and the recovery operation is performed at a timing when it is executable. This is a process in which Note that the preliminary operation performed at this time is a preliminary operation for executing the recovery operation selected in S1404 of FIG. In FIG. 15, at the timing of starting the recovery operation, it is determined whether the recovery operation is to be performed based on the predicted ink flow velocity in the circulation flow path. The process in FIG. 15 is also a process that is repeatedly executed by the recording control unit 301 at a predetermined timing after the timing when the recovery operation becomes executable and before the recovery operation is actually executed. Further, the processing from S1501 to S1507 is performed for each ink color.

First, in S1501, the recording control unit 301 sets an allowable value V2 (also referred to as a predetermined flow velocity) of the circulating flow velocity during the recovery operation, which corresponds to the recovery operation selected in S1404. FIG. 16 is a diagram showing a table in which allowable values V2 are set for each ink color and type of recovery operation. In this embodiment, the table shown in FIG. 16 is held in the memory 303 in advance. In S1501, the recording control unit 301 refers to the table value of the selected recovery operation and determines the permissible value V2 of the circulating flow velocity during the recovery operation. For example, when wiping the cyan ink ejection port array with the first wiper 221 and the second wiper 222, which are wiper blades of the recovery unit 210, V2=0.5 mm/s. In addition, when using a recovery unit having a plurality of wiping members, the permissible value V2 of the circulating flow velocity may be changed depending on the member to be wiped. At this time, in the case of a highly absorbent wiping member such as a nonwoven fabric, the amount of ink that enters the ejection port due to wiping is smaller than in the case of a wiper blade made of an elastic member, so the allowable value V2 may be large. In addition, in the case of suction operation, negative pressure is applied to the cap unit and ink is sucked out from the ejection port, so the permissible flow rate is not set because there is no effect of the presence or absence of circulation flow speed, and the suction operation is performed immediately after the preliminary operation. Good too. In the table of FIG. 16, no allowable value is defined when a suction operation is performed. Further, for example, if the recovery operation is a sequence in which a wiping operation is performed after a suction operation, a large circulation flow velocity will not occur unless the circulation drive pump 408 is driven again after the suction operation. Therefore, even if the sequence includes a wiping operation, wiping may be performed without providing a waiting time. Note that in this embodiment, processing according to the table shown in FIG. 16 will be explained, but if, for example, the tolerance value V2 is uniformly set to "0", the processing will be substantially the same as the processing described in the first embodiment. Become.

Next, in S1502, the recording control unit 301 obtains a time T5 during which the circulating flow velocity becomes equal to or less than the allowable value V2. The recording control unit 301 refers to the flow velocity table shown in FIG. 12. Then, the time T5 from when the circulation drive is stopped until the flow velocity reaches the allowable value V2 or less (predetermined flow velocity or less) set in S1501 is determined with reference to the table shown in FIG. 12. If there is no flow velocity value in the table that matches the circulating flow velocity tolerance value V2, T5 may be determined by linear interpolation from previous and subsequent predicted flow velocity values. For example, when V2 of cyan ink is 0.5 mm/s, the time T5 is approximately 21.4 seconds after linear interpolation. In other words, when time T5 (approximately 21.4 seconds) has elapsed since the circulation drive was stopped, the flow rate will decrease to a circulation flow rate that allows the selected recovery operation. Therefore, as described in the next step S1504, it is possible to determine whether or not the recovery operation can be performed by comparing the elapsed time T4, which is a timer, and the time T5 since the circulation drive was stopped.

In addition, in this embodiment, the example which referred to the table which defined the elapsed time and predicted flow velocity value since the circulation drive stop was demonstrated, but is not limited to this. The flow velocity of ink within the circulation channel may be actually measured. In addition, by calculating the flow velocity based on the ink flow rate in the circulation channel and the pressure difference between the first pressure control member 406 and the second pressure control member 407, it is possible to determine whether the flow velocity falls below the allowable value V2. You may judge. In this case, since it is possible to determine whether to perform the recovery operation without depending on the elapsed time T4 from the stop of the circulation drive, it is not necessary to count the elapsed time T4.

In S1504, the recording control unit 301 compares and determines T4 and T5. If T4>T5, the process advances to step S1505, where the recording control unit 301 determines that the ink is in a recovery operation-enabled state, and turns on the recovery operation-enabled flag of the ink. Then, the process advances to S1507. On the other hand, if T4≦T5, the process advances to S1506, where the recording control unit 301 determines to continue the wait without starting the recovery operation, and ends the process at this timing.

The above processing from S1501 to S1506 is executed for each ink based on the determination in S1507. In the determination in S1508, if all the recovery operation enable flags for the target ink of the recovery operation are ON, the process advances to S1509 and the recovery operation is executed. On the other hand, in the determination in S1507, if the recovery operation enable flags for all inks are not turned on, the process advances to S1510, continues waiting, and ends this flow. In this case, the process of FIG. 15 will be executed again at a predetermined timing.

FIG. 17 is a diagram showing the execution timing at which the recovery operation is executed in S1509. In FIG. 17, the circulation drive is stopped during the recording operation. Further, at the timing when the recording operation is completed, the circulating flow velocity maintains the required flow velocity V1. Furthermore, wiping is executed at a time when a time T5 in which the circulation flow velocity becomes equal to or less than the allowable value V2 has elapsed from the timing at which the circulation drive was stopped. At this time, although the circulation has not completely stopped, the flow rate is lower than the allowable value V2. Therefore, even if the recovery operation is executed, it is possible to prevent foreign matter from entering deep inside the ejection port.

Note that in this embodiment, an example has been shown in which the recovery operation execution flag is managed for each ink and repeated determination is performed, considering the case where the execution content of the recovery operation is different for each ink color, but this is not the case. For example, in the case where the same recovery operation is performed simultaneously for all ink ejection ports, the timer may start counting according to the ink whose count starts the latest for the elapsed time T4. Also, when comparing the elapsed time T4 and the time T5 when the circulation flow velocity becomes less than the allowable value, the recovery start timing is determined when the circulation drive of all ink colors has stopped and the type of recovery operation after the recording operation has been determined. may be determined. That is, in this embodiment, an example has been described in which the process in FIG. 15 and the process in FIG. 14 are executed at different timings, but the process corresponding to FIG. 15 may be incorporated in the circulation drive stop determination flow in FIG. 14.

As described above, according to the present embodiment, even when executing a recovery sequence that includes a plurality of recovery operations, the recovery operations can be executed at suitable timing. In this embodiment, the execution timing of the recovery operation is determined according to the timing at which the circulation drive pump 408 is stopped. The timing at which the circulation drive pump 408 is stopped is a timing at which the ejection characteristics are not affected at the end of the recording operation. The timing at which the recovery operation is performed is the timing at which the ink flow velocity within the circulation channel becomes equal to or lower than the allowable flow velocity for each ink. As a result, the amount of ink or foreign matter that enters deep into the circulation flow path during the recovery operation can be suppressed, and the range can be kept within a range that can be discharged by preliminary ejection. As a result, it is possible to prevent the ink in the circulation flow path from mixing with the ink that has entered, causing problems such as changing the color tone of the recorded image and deteriorating the ejection characteristics. It becomes possible.

<<Other embodiments>>
In each of the embodiments described above, a so-called serial type print head is used, in which the print head 110 is mounted on the carriage unit 102 and ink is ejected from the print head 110 in accordance with the reciprocal scanning of the carriage. However, a so-called line-type recording head may be used, in which the ejection openings of the recording head are provided along the length of the recording medium in the width direction. When using a line-type recording head, an image may be recorded on the recording medium by ejecting ink onto the recording medium without the recording head scanning back and forth. Even when a line-type print head is used, it is possible to calculate the remaining time of the print operation in S1001 of FIG. 10. For example, the remaining time of the printing operation can be calculated from the unrecorded area of image data and the conveyance speed of the printing medium.

Further, in each of the above-described embodiments, the circulation drive pump 408 is included in the print head 110, but the circulation drive pump is provided outside the print head, that is, on the main body side. It may be in the form of In either embodiment, each of the embodiments described above is useful when a predetermined time is required from when the circulation drive pump is stopped to when the circulation within the circulation channel is stopped.

Further, in each of the embodiments described above, an example has been described in which ink flows even after the circulation drive pump 408 is stopped due to the pressure difference between the two pressure control members, but the invention is not limited to this example. The embodiment described above is applicable to any form as long as the movement of ink does not stop immediately after the circulation drive pump 408 is stopped and the ink can flow.

The present invention provides a system or device with a program that implements one or more functions of the embodiments described above via a network or a storage medium, and one or more processors in a computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The disclosure of this embodiment includes configurations typified by the following example of a recording device and example of a control method for the recording device.

<Configuration 1>
a recording head having an ejection port for ejecting ink;
a driving means for driving ink within the recording head to pass through the ejection port;
recovery means for performing a recovery operation of the recording head after the recording operation by the recording head;
control means for controlling execution timing of the recovery operation by the recovery means;
A recording device having:
A recording apparatus characterized in that, when performing a recording operation using the recording head while moving ink by driving by the driving means, the control means stops the driving means before the recording operation is completed.

<Configuration 2>
The recording apparatus according to configuration 1, wherein the control means determines the execution timing of the recovery operation according to the timing at which the drive means is stopped.

<Configuration 3>
The control means may stop the driving means before the recording operation ends so that the flow velocity at the timing at which the recording operation ends is higher than the flow velocity at which ejection characteristics are maintained. The recording device according to configuration 1 or 2.

<Configuration 4>
The control means, based on the time required for the remaining recording operation, the flow velocity predicted according to the elapsed time after stopping the driving means, and the flow velocity at which the ejection characteristics are maintained during the recording operation, The recording apparatus according to configuration 3, wherein the driving means is stopped.

<Configuration 5>
5. The recording apparatus according to configuration 3 or 4, wherein the flow rate at which the ejection characteristics are maintained varies depending on the recording mode in which the recording operation is performed.

<Configuration 6>
6. The recording apparatus according to any one of configurations 3 to 5, wherein the flow rate at which the ejection characteristics are maintained varies depending on the type of ink.

<Configuration 7>
The control means causes the recovery means to perform the recovery operation after a first time period has elapsed since the drive means is stopped and the flow velocity of the ink becomes equal to or less than a predetermined flow velocity. 6. The recording device according to any one of 6.

<Configuration 8>
8. The recording device according to configuration 7, wherein the predetermined flow velocity is 0.

<Configuration 9>
8. The recording apparatus according to configuration 7, wherein the predetermined flow velocity is a flow velocity determined according to a type of the recovery means and at which execution of the recovery means is permitted.

<Configuration 10>
The timing at which the flow rate becomes equal to or less than the predetermined flow rate is determined based on the elapsed time since the driving means is stopped and the flow rate predicted according to the elapsed time since the driving means is stopped. The recording device according to any one of features 7 to 9.

<Configuration 11>
The recording head includes a first pressure control member connected to a first flow path communicating with the ejection port, and a second pressure control member connected to a second flow path communicating with the ejection port,
According to any one of configurations 7 to 9, the ink moves through the ejection port depending on the pressure difference between the first pressure control member and the second pressure control member. Recording device.

<Configuration 12>
12. The recording apparatus according to configuration 11, wherein the timing at which the flow rate becomes equal to or lower than the predetermined flow rate is determined based on a pressure difference between the first pressure control member and the second pressure control member.

<Configuration 13>
12. The recording device according to configuration 11, wherein the timing at which the flow rate becomes equal to or less than the predetermined flow rate is determined by measuring the flow rate in at least one of the first flow path and the second flow path.

<Configuration 14>
14. The recording apparatus according to any one of configurations 7 to 13, wherein the control means does not execute the recovery operation until the flow rate becomes equal to or less than the predetermined flow rate.

<Configuration 15>
The control means performs the recovery operation after a time period obtained by adding a predetermined waiting time to a second time period from the end of the recording operation to the time required for a preliminary operation before the recovery operation is executed by the recovery means. is configured to run
Recording according to any one of configurations 1 to 8, wherein the predetermined standby time is determined based on a third time from when the driving means is stopped until the recording operation is completed. Device.

<Configuration 16>
The recovery means executes a recovery operation according to a recovery sequence including a type of recovery operation, a member of the recovery means, and a combination thereof, and the second time varies depending on the recovery operation according to the recovery sequence. 16. The recording device according to configuration 15.

<Configuration 17>
17. The recording device according to configuration 16, wherein the recovery operation according to the recovery sequence can change while performing the recording operation.

<Configuration 18>
The recording head is equipped with a plurality of types of ink, and
The recovery means applies a recovery operation for each ink,
18. The recording apparatus according to any one of configurations 1 to 17, wherein the control means determines a common recovery operation timing for all inks.

<Configuration 19>
19. The recording device according to any one of configurations 1 to 18, wherein when the recovery operation is a predetermined recovery operation, the control means does not stop the driving means before the recording operation is completed. .

<Configuration 20>
20. The recording apparatus according to configuration 19, wherein the predetermined recovery operation includes an operation of suctioning the ejection port surface of the recording head.

<Configuration 21>
21. According to any one of configurations 1 to 20, when the recovery operation is not performed after the recording operation, the control means does not stop the driving means before the recording operation is completed. Recording device.

<Configuration 22>
a recording head having an ejection port for ejecting ink;
a driving means for driving ink within the recording head to pass through the ejection port;
recovery means for performing a recovery operation of the recording head after the recording operation by the recording head;
A recording device having:
A method for controlling a recording apparatus, characterized in that, when a recording operation is performed using the recording head while moving ink by driving by the driving means, the method includes the step of stopping the driving means before the recording operation is completed. .

110 Recording head 210 Recovery unit 301 Recording control section 402 Discharge port 408 Circulation drive pump

Claims (22)

a recording head having an ejection port for ejecting ink;
a driving means for driving ink within the recording head to pass through the ejection port;
recovery means for performing a recovery operation of the recording head after the recording operation by the recording head;
control means for controlling execution timing of the recovery operation by the recovery means;
A recording device having:
A recording apparatus characterized in that, when performing a recording operation using the recording head while moving ink by driving by the driving means, the control means stops the driving means before the recording operation is completed. 2. The recording apparatus according to claim 1, wherein the control means determines the execution timing of the recovery operation according to the timing at which the drive means is stopped. The control means may stop the driving means before the recording operation ends so that the flow velocity at the timing at which the recording operation ends is higher than the flow velocity at which ejection characteristics are maintained. The recording device according to claim 1 or 2. The control means, based on the time required for the remaining recording operation, the flow velocity predicted according to the elapsed time after stopping the driving means, and the flow velocity at which the ejection characteristics are maintained during the recording operation, 4. The recording apparatus according to claim 3, wherein the driving means is stopped. 4. The recording apparatus according to claim 3, wherein the flow rate at which the ejection characteristics are maintained varies depending on the recording mode in which the recording operation is performed. 4. The recording apparatus according to claim 3, wherein the flow rate at which the ejection characteristics are maintained varies depending on the type of ink. 2. The control means causes the recovery means to perform the recovery operation after a first time period in which the ink flow rate becomes equal to or less than a predetermined flow rate after stopping the drive means has elapsed. Or the recording device according to 2. 8. The recording device according to claim 7, wherein the predetermined flow rate is zero. 8. The recording apparatus according to claim 7, wherein the predetermined flow velocity is a flow velocity determined according to the type of the recovery means and at which execution of the recovery means is permitted. The timing at which the flow rate becomes equal to or less than the predetermined flow rate is determined based on the elapsed time since the driving means is stopped and the flow rate predicted according to the elapsed time since the driving means is stopped. The recording device according to claim 7, characterized in that: The recording head includes a first pressure control member connected to a first flow path communicating with the ejection port, and a second pressure control member connected to a second flow path communicating with the ejection port,
8. The recording apparatus according to claim 7, wherein the ink moves through the ejection port according to a pressure difference between the first pressure control member and the second pressure control member. 12. The recording apparatus according to claim 11, wherein the timing at which the flow rate becomes equal to or lower than the predetermined flow rate is determined based on a pressure difference between the first pressure control member and the second pressure control member. 12. The recording apparatus according to claim 11, wherein the timing at which the flow rate becomes equal to or less than the predetermined flow rate is determined by measuring the flow rate in at least one of the first flow path and the second flow path. 8. The recording apparatus according to claim 7, wherein the control means does not execute the recovery operation until the flow rate becomes equal to or less than the predetermined flow rate. The control means performs the recovery operation after a time period obtained by adding a predetermined waiting time to a second time period from the end of the recording operation to the time required for a preliminary operation before the recovery operation is executed by the recovery means. is configured to run
2. The recording apparatus according to claim 1, wherein the predetermined standby time is determined based on a third time period from when the driving means is stopped until the recording operation is completed. The recovery means executes a recovery operation according to a recovery sequence including a type of recovery operation, a member of the recovery means, and a combination thereof, and the second time varies depending on the recovery operation according to the recovery sequence. 16. The recording device according to claim 15. 17. The recording apparatus according to claim 16, wherein the recovery operation according to the recovery sequence can change while performing the recording operation. The recording head is equipped with a plurality of types of ink, and
The recovery means applies a recovery operation for each ink,
3. The recording apparatus according to claim 1, wherein the control means determines a common recovery operation timing for all inks. 3. The recording apparatus according to claim 1, wherein when the recovery operation is a predetermined recovery operation, the control means does not stop the driving means before the recording operation is completed. 20. The recording apparatus according to claim 19, wherein the predetermined recovery operation includes an operation of suctioning the ejection port surface of the recording head. 3. The recording apparatus according to claim 1, wherein if the recovery operation is not performed after the recording operation, the control means does not stop the driving means before the recording operation is completed. a recording head having an ejection port for ejecting ink;
a driving means for driving ink within the recording head to pass through the ejection port;
recovery means for performing a recovery operation of the recording head after the recording operation by the recording head;
A recording device having:
A method for controlling a recording apparatus, characterized in that, when a recording operation is performed using the recording head while moving ink by driving by the driving means, the method includes the step of stopping the driving means before the recording operation is completed. .

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