Liquid discharge device and control method of liquid discharge device

Abstract

To suppress mixing of foreign matter or the like into a flow passage during a recovery operation.SOLUTION: A liquid discharge device includes: a liquid discharge head having a discharge port for discharging liquid; circulation means which circulates liquid in the liquid discharge head so as to pass through a pressure chamber communicating with the discharge port; recovery means which performs a recovery operation of the liquid discharge head at a circulation flow rate slower than circulation flow rate by the circulation means when an image is recorded on a recording medium by the liquid discharge head; and control means which performs control to perform preliminary discharge for discharging liquid which is not used for recording from the discharge port in parallel with the recovery operation by the recovery means.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection device and a method for controlling the liquid ejection device.

Background Art

[0002] In an inkjet recording apparatus, a configuration is known in which ink is circulated so as to pass through a flow path communicating with each of ejection ports arranged at high density and a pressure chamber corresponding to the ejection port, thereby suppressing an increase in the viscosity of the ink in the ejection port (Patent Document 1). In Patent Document 1, a pressure difference between two pressure adjustment mechanisms is used to generate a flow of ink so as to pass through the pressure chamber.

[0003] Also, 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 the ink adhering to the ejection port array surface penetrates into the ejection port and mixes, or foreign matter may be pushed into the ejection port. Usually, such color mixing and foreign matter are removed by a preliminary ejection or suction operation.

[0004] Here, in a configuration in which the ink in the ejection port is circulated as in Patent Document 1, if the recovery operation of the ejection port array surface is performed while the ink in the ejection port is being circulated, the mixed-color ink and foreign matter in the ejection port may penetrate deep into the circulation flow path and may become impossible to remove. Patent Document 2 describes a configuration in which the circulation pump is stopped when performing the recovery operation of the ejection port array surface.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] 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 the ink passing through the discharge port completely stops. For example, when the flow of ink is generated by the pressure difference between the pressure regulating mechanisms as in Patent Document 1, the flow of ink can occur in the circulation flow path including the inside of the discharge port until the pressure difference is eliminated. Therefore, for example, when performing the recovery of the discharge port array surface after stopping the circulation drive after the recording operation, if the time from the end of the recording operation to the start of the recovery operation is short, the recovery operation will be performed with the circulation flow velocity in the discharge port not stopping. In that case, the mixed-color ink or foreign matter may enter to the back of the flow path due to the circulation flow velocity and may not be removable by the preliminary discharge or suction operation. As a result, there is a risk of abnormal color tone of the recorded image, deviation of the landing of ink droplets, and non-discharging nozzles.

[0007] On the other hand, if the circulation drive is stopped after the recording operation and a waiting time is provided until the circulation flow velocity stops, as a result, the start of the recovery operation will be delayed, which may lead to a decrease in productivity.

[0008] An object of the present disclosure is to suppress the entry of foreign matters and the like into the flow path during the recovery operation.

Means for Solving the Problems

[0009] A liquid discharge device according to an aspect of the present disclosure includes a liquid discharge head having a discharge port for discharging a liquid, a circulation means for circulating the liquid in the liquid discharge head so as to pass through a pressure chamber communicating with the discharge port, a recovery means for performing a recovery operation of the liquid discharge head at a circulation flow velocity slower than the circulation flow velocity by the circulation means when recording an image on a recording medium by the liquid discharge head, and a control means for controlling a preliminary discharge for discharging a liquid not used for recording from the discharge port in parallel with the recovery operation by the recovery means.

Effects of the Invention

[0010] According to the present disclosure, it is possible to suppress the entry of foreign matter or the like into the flow path during the recovery operation.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Mode for Carrying Out the Invention

[0012] 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 present disclosure, and not all combinations of features described in the embodiments are essential for the solution means of the present disclosure. The same reference numerals are assigned to the same components.

[0013] In this specification, "recording" shall include not only the case of forming significant information such as characters and figures, but also anything regardless of whether it is significant or not. Also, "recording" shall represent not only the case where it is made manifest so that it can be perceived visually by humans, but also the case of forming an image, pattern, pattern, etc. on a recording medium or processing the medium widely. "Recording medium" shall represent not only paper used in general recording devices, but also widely, cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc., which can receive ink. "Ink" (sometimes referred to as "liquid") shall be interpreted widely in the same manner as the definition of "recording" above. Therefore, it represents a liquid that can be used for forming an image, pattern, pattern, etc., processing the recording medium, or treating the ink (for example, coagulating or insolubilizing a coloring material in the ink applied to the recording medium) by being applied on the recording medium. "Nozzle" shall generally refer to a discharge port, a liquid path communicating with the discharge port, and an element that generates energy used for ink discharge, unless otherwise specified.

[0014] Ink used in an inkjet recording apparatus is generally added with a resin or the like in order to improve image quality and fastness. The addition of a resin or the like is performed to improve color developability by retaining a coloring material on a recording medium as the viscosity of the ink increases with evaporation of moisture, or to improve fastness by protecting the coloring material with a resin film. Here, when ejection ports are arranged at a high density and smaller droplets are ejected to improve image quality, thickening of the ink due to evaporation of moisture may occur inside the ejection ports. As a result, ejection of ink droplets may be inhibited, causing disturbance in the landing positions of the ink droplets on the recording medium or non-ejection, which may deteriorate the image quality.

[0015] The inkjet recording apparatus according to this embodiment suppresses thickening of the ink inside the ejection ports by circulating the ink so as to pass through the ejection ports. Then, in such an inkjet recording apparatus, an example of suppressing mixing of mixed-color ink or foreign matter into the flow path during a recovery operation while suppressing a decrease in productivity will be specifically described below.

[0016] <<First Embodiment>> <Configuration of Liquid Ejection Device> FIG. 1 is a diagram showing an external appearance of a liquid ejection device according to this embodiment. The liquid ejection device according to this embodiment is an inkjet recording apparatus (hereinafter, also simply referred to as a recording apparatus). The recording apparatus 101 according to this embodiment is a so-called serial scanning type printer. The recording apparatus 101 records an image by scanning a recording head 110, which is a liquid ejection head, in the X direction (scanning direction) orthogonal to the Y direction (conveying direction) in which a recording medium 103 is conveyed.

[0017] The configuration of the recording apparatus 101 and the outline of the operation during recording will be described with reference to 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 via a gear by a conveyance motor 204 (FIG. 2). The fed recording medium 103 is sandwiched and conveyed between a paper feed roller and a pinch roller, and is guided to a recording position (scanning area of the recording head 110) on the platen 104. On the other hand, at a predetermined conveyance position, the carriage motor 205 (FIG. 2) reciprocally scans (reciprocally moves) the carriage unit 102 in the X direction along a guide shaft 108 extending in the X direction. A recording head 110 is mounted on the carriage unit 102. Then, during this scanning process, ejection operation is performed from the nozzles (ejection ports) of the recording head 110 at a timing based on the position signal obtained by the encoder 107, and recording with a constant bandwidth corresponding to the array range of the ejection ports is performed. Thereafter, the recording medium 103 is conveyed, and recording of the next bandwidth is further performed. In this way, by alternately performing the conveyance of the recording medium 103 and the recording scan by the recording head 110, a desired image is configured to be recorded on the recording medium 103.

[0018] Incidentally, usually, in the standby state, capping is performed on the face surface of the recording head 110 by a cap 211 provided in a recovery unit 210 (FIG. 4) described later. For this reason, prior to recording, the cap 211 is opened to make the recording head 110 (carriage unit 102) in a scanable state. Thereafter, when data for one scan is accumulated in the buffer, the carriage motor 205 scans the carriage unit 102, and the recording operation as described above is performed.

[0019] Note that a carriage belt (not shown) can be used for transmitting the driving force from the carriage motor 205 to the carriage unit 102. However, instead of the carriage belt, for example, a lead screw that is rotationally driven by the carriage motor 205 and extends in the X direction, and an engagement portion provided on the carriage unit 102 and engaged with the groove of the lead screw may be used. In this way, it is also possible to use other driving methods.

[0020] Also, the ink supplied to the recording head 110 is supplied from the ink tank 202 (Fig. 5) mounted on the main body of the recording apparatus 101 or an external unit to the carriage unit 102 via the supply tube 105. The ink may be supplied from the ink tank 202 to the recording head 110 using a pressurizing unit. Alternatively, the discharge port surface of the recording head 110 may be capped using the cap 211 of the recovery unit 210, and the ink may be supplied by applying a negative pressure into the cap and sucking it by the suction pump 213 (Fig. 4).

[0021] A plurality of recording heads 110 capable of discharging one or a plurality of colors of ink may be mounted on the carriage unit 102, or a form in which one recording head 110 capable of discharging a plurality of colors of ink is mounted on the carriage unit 102 may be used. Further, a form in which one or a plurality of recording heads 110 capable of discharging a single color of ink are mounted on the carriage unit 102 may also be used. In the present embodiment, a serial scanning type printer has been described as an example, but a recording apparatus equipped with a full-line type recording head may also be used.

[0022] <Recording control> FIG. 2 is a block diagram showing the configuration of the recording control system in the recording apparatus 101 shown in FIG. 1.

[0023] The recording device 101 is connected to a data supply device such as a host computer (hereinafter referred to as the host PC) 306 via the interface 307. Various data transmitted from the host PC 306 or control signals related to recording are input to the recording control unit 301 of the recording device 101. The recording control unit 301 includes a memory 303 that stores input image data, multi-valued gradation data of intermediate products, and a multi-pass mask, and a CPU 302 (which may be an ASIC) that is a control arithmetic device. The recording control unit 301 also includes an image processing unit 304 that performs various image processes and a data processing unit 305 that performs various data processes. The processes of the image processing unit 304 and the data processing unit 305 may be executed by the CPU 302. The recording control unit 301 controls the motor driver and the head driver described later according to the control signal input via the interface 307.

[0024] 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 reciprocally drives a 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, switches a unit driven by a camshaft, and operates the wiper guide 223 and the suction pump 213 (Fig. 4). The motor drivers 308, 309, 310 are drivers that rotationally drive the conveyance motor 204, the carriage motor 205, and the recovery unit motor 206, respectively. The head driver 311 is a driver that drives the recording head 110. When a plurality of recording heads are mounted, a plurality of them are provided corresponding to the number.

[0025] <Recording head configuration> FIG. 3 is a diagram for explaining the configuration of the recording head 110 in the present embodiment. FIG. 3 is a diagram showing an example of the recording head 110 and the configuration of the ejection port group. The recording head 110 in the present embodiment is provided with independent buffer tanks 401C, 401M, 401Y, and 401BK corresponding to four colors of ink: cyan, magenta, yellow, and black. In FIG. 3, the buffer tanks are shown for the purpose of explanation so that they can be visually recognized, but the buffer tanks are stored inside the recording head 110. On the lower surface (+Z direction) of the recording head 110, chips 403 in which ejection port arrays corresponding to the respective inks are formed are arranged. In the chip 403, 1024 ejection ports 402 are formed in two rows at intervals of 1200 dpi per color, and it is possible to eject two colors with one chip. By arranging two such chips 403, four-color recording is possible. Note that the ejection port arrays of one color do not need to be arranged on the same straight line, and they may be arranged alternately one by one, and a total of four rows of 512 ejection port arrays may be arranged at intervals of 600 dpi. In FIG. 3, the configuration in which independent buffer tanks are provided for four colors of ink has been described as an example, but they may all be the same color, and the number and arrangement of ink colors can take any form.

[0026] <Recovery unit> FIG. 4 is a schematic diagram of the recovery unit 210 according to the present embodiment. The recovery unit 210 includes a cap 211 that covers the ejection port surface of the recording head 110, and a suction pump 213 that sucks ink from the recording head 110 in a state where 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 (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 needed 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 stops at the standby position.

[0027] The cap 211 is supported so as to be movable up and down by a lifting mechanism (not shown) and moves between the raised position and the lowered position. When in the raised position, the cap 211 abuts against the recording head 110 and covers (caps) the discharge port surface of the recording head 110. By covering the discharge port surface of the recording head 110, the cap 211 can suppress the drying of the discharge port 402 of the recording head and the evaporation of the ink during the non-recording operation. Further, the cap 211 can suck the ink from the recording head 110 by driving a suction pump 213 described later. Also, during the recording operation, the cap 211 is positioned at the lowered position to avoid interference with the recording head 110 that moves together with the carriage unit 102. In a state where the cap 211 is positioned at the lowered position, when the recording head 110 moves to a position facing the cap 211, the recording head 110 can perform preliminary discharge with respect to the cap 211. The preliminary discharge is the discharge of ink not used for recording on the recording medium 103, and is an operation for discharging the mixed-color ink, foreign matter, thickened ink, etc. that have entered the recording head (inside the liquid discharge head) to the outside of the recording head.

[0028] The first wiper (wiper blade) 221 and the second wiper (wiper blade) 222 are composed of an elastic member such as rubber. In the present embodiment, as shown in FIG. 2, two first wipers 221 that wipe the discharge port surfaces of the two chips 403 respectively, and a second wiper 222 that wipes the entire discharge port surface including the discharge port row are provided. 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 of the figure (the arrangement direction of the discharge ports in the recording head, that is, the Y direction) indicated by the arrow W. When the recording head 110 is located at the standby position, by moving the wiper holder 220 in the direction of the arrow W (one direction), the first wiper 221 and the second wiper 222 can perform a wiping operation of wiping the discharge port surface while being in contact with the discharge port surface. When the wiping operation is completed, the carriage unit 102 is moved and retracted 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).

[0029] In addition, in the present embodiment, an example having the first wiper 221 and the second wiper 222 is used for explanation, but a configuration having only one of the wipers may be adopted. Further, in the present embodiment, an example in which the wiper is composed of an elastic member such as rubber is described, but it may be a member composed of a porous material that absorbs ink. Further, the wiper may have a configuration of a vacuum wiper capable of sucking the discharge port surface. Further, in the present embodiment, an example in which wiping is performed only when the wiper moves in one direction is described, but a configuration in which wiping is performed when the wiper moves in a reciprocating bidirectional manner may be adopted. Further, in the present embodiment, an example in which the wiping direction is the arrangement direction (Y direction) of the discharge ports in the recording head is described, but a configuration in which the wiper moves in a direction (the arrangement direction of the discharge port rows, X direction) intersecting (orthogonal to) the direction may be adopted. Further, in such a configuration, a configuration in which the wiper is fixed and the carriage unit 102 moves in the scanning direction to wipe the discharge port surface may be adopted. Further, a configuration in which the wiper moves in both the X direction and the Y direction to perform wiping may also be adopted. Further, in a configuration in which a plurality of wiping members or wiping is performed in different wiping directions, the positions of the respective recovery units may be separately arranged. 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.

[0030] When the discharge port surface is wiped by the wiper, there is a possibility that mixed-color ink or the like may enter the discharge ports on the downstream side of the wiping. Therefore, in the present embodiment, a preliminary discharge operation is performed after the recovery operation by wiping.

[0031] The suction pump 213 is driven in a state where the cap 211 covers the discharge port surface of the recording head 110 and the inside thereof is made into a substantially airtight space. Thereby, by generating a 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 the recording head 110 with ink from the ink tank 202 (during initial filling), or when sucking and removing dust, deposits, or air bubbles inside the discharge port (during suction recovery). The cap 211 is connected to a waste ink absorber (not shown) via a flexible tube 212.

[0032] In the present embodiment, a tube pump is used as the suction pump 213. The tube pump includes a holding portion formed with a curved surface portion that holds at least a part of the tube 212, a roller that can press the held tube 212, and a roller support portion that rotatably supports the roller. The tube pump rotates the roller while crushing the tube 212 by rotating the roller support portion in a predetermined direction. Thereby, a negative pressure is generated inside the cap 211, and ink is sucked from the recording head 110. The sucked ink is discharged to the waste ink absorber through the tube 212. Further, the suction operation is also performed when discharging the ink received in the cap 211 to the outside of the cap 211 by preliminary discharge when the recording head 110 performs preliminary discharge on the cap 211. That is, when the amount of ink preliminarily discharged and held in the cap 211 reaches a predetermined amount, by driving the suction pump 213, the ink held in the cap 211 can be discharged to the waste ink absorber through the tube 212.

[0033] As described above, the recovery unit 210 performs a recovery operation for recovering the discharge port surface to a normal state. The recovery operation may be referred to as a cleaning operation or a purging operation. Further, the recovery unit 210 may be referred to as a maintenance unit that performs maintenance on the discharge port surface.

[0034] <Ink Circulation> FIG. 5 is a diagram schematically showing the configuration of the recording head 110. Here, it is a schematic diagram of the flow path for one color. In the present embodiment, as described above, buffer tanks and flow paths for four colors, cyan, magenta, yellow, and black, are configured in one recording head 110. The supply tube 105 connected to the ink tank 202 is connected to the joint 404 of the head body 120 through the inside of the carriage unit 102 and communicates with the buffer tank 401. The supplied ink passes through the filter 405, passes through the flow path in the buffer tank 401, and reaches the first pressure control chamber 406. The first pressure control chamber 406 is connected to the second pressure control chamber 407, which is another pressure control chamber, through a flow path, and is also connected to the second pressure control chamber 407 through another flow path via the circulation drive pump 408.

[0035] A valve 411 that opens when a predetermined negative pressure is reached is provided at the inlet of the first pressure control chamber 406. A valve 412 that opens when a predetermined negative pressure is reached is provided at the inlet of the second pressure control chamber 407. The inlet of the first pressure control chamber 406 is provided in the flow path between the first pressure control chamber 406 and the filter 405. The inlet of the second pressure control chamber 407 is provided in the flow path between the second pressure control chamber 407 and the first pressure control chamber 406. The negative pressure at which the valve 412 at the inlet of the second pressure control chamber 407 opens is configured to be higher than the negative pressure at which the valve 411 of the first pressure control chamber 406 opens.

[0036] Ink is supplied from the first pressure control chamber 406 into the chip 403 through the common supply flow path 409 formed in the head body 120. Specifically, ink is supplied from the common supply flow path 409 to the supply flow path (described later) of one or a plurality of ejection port rows arranged in the chip 403. Then, the ink is ejected from the ejection port 402. Also, the ink that is not ejected is recovered into the buffer tank 401 via the ejection port 402. That is, the ink that has passed through the ejection port 402 passes through the common recovery flow path 410 formed in the head body 120 from the recovery flow path (described later) in the chip 403 and is recovered into the second pressure control chamber 407.

[0037] FIG. 6 is a diagram showing the configuration of the discharge 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 discharge port 402 is arranged). Hereinafter, with reference to FIGS. 6 and 7, the configuration of the discharge port 402 and the flow path formed in the chip 403 and the flow of ink will be described. The discharge port 402 is formed in the orifice plate 420 on the surface of the chip 403. An energy generating element 423 that generates discharge energy for discharging ink is provided at a position (pressure chamber 424) corresponding to the discharge port 402 on the substrate 430. That is, an energy generating element 423 is provided corresponding to each of the discharge ports 402. As the energy generating element 423, an electrothermal conversion element (heater) or a piezoelectric element can be used. When a heater is used, the ink in the discharge port 402 is foamed by its heat generation, and the ink can be discharged from the discharge port 402 by utilizing the foaming energy.

[0038] When ink is supplied, the chip 403 is maintained at a negative pressure such that a meniscus is formed on the ejection port surface. Two flow paths, an inlet 421 and an outlet 422, are respectively formed on both sides of the ejection port 402. In the present embodiment, as shown in FIG. 7, one inlet 421 and one outlet 422 are arranged corresponding to each of the two ejection ports 402. Note that the number of inlets 421 and outlets 422 may be one for each ejection port 402, may be one for each of more than two ejection ports 402, and the number of inlets 421 and outlets 422 may not be the same. As shown in FIG. 6, the inlet 421 and the outlet 422 are respectively connected to a supply flow path 431 and a recovery flow path 432 formed along the ejection port row direction (Y direction). The supply flow path 431 and the recovery flow path 432 are covered with a cover plate 440 and are connected to a common supply flow path 409 and a common recovery flow path 410 of the head body 120 through an opening 441 on the cover plate. One or more openings 441 are provided for each of the supply flow path 431 and the recovery flow path 432. Note that the number of openings 441 may be the same or different for the supply flow path and the recovery flow path. The common supply flow path 409 or the supply flow path 431 is also referred to as a first flow path, and the common recovery flow path 410 or the recovery flow path 432 is also referred to as a second flow path.

[0039] Next, with reference to FIG. 5, an ink supply method to the recording head 110 and the buffer tank 401, and an ink circulation method in the discharge port in the present embodiment will be described. The ink is pressurized from the ink tank 202 and reaches inside the recording head 110 through the supply tube 105, passes through the filter 405, and flows into the flow path in front of the valve 411 arranged at the inlet of the first pressure control chamber 406. When the inside of the recording head is filled with ink at an appropriate negative pressure so that a meniscus is held on the discharge port surface, the valve 411 arranged at the inlet of the first pressure control chamber 406 is in a closed state, and the ink does not flow into the first pressure control chamber 406. On the other hand, when a strong negative pressure is applied to the discharge port 402 by the suction operation using the cap 211 of the recovery unit 210, or when the negative pressure in the first pressure control chamber 406 becomes high when ink is discharged from the discharge port 402, the valve 411 at the inlet opens. Then, the ink flows into the first pressure control chamber 406.

[0040] As shown in FIG. 5, the first pressure control chamber 406 and the second pressure control chamber 407 are connected to the circulation drive pump 408. When the circulation drive pump 408 is driven, ink is transferred from the second pressure control chamber 407 to the first pressure control chamber 406 via the circulation drive pump 408. As a result, the negative pressure in the second pressure control chamber 407 increases, and the valve 412 at the inlet of the second pressure control chamber 407 opens, allowing ink to flow back from the first pressure control chamber 406 to the second pressure control chamber 407. At this time, since a pressure difference is generated between the first pressure control chamber 406 and the second pressure control chamber 407, a flow of ink passing through the discharge port 402 is generated. That is, ink passes through the flow path in the order of the first pressure control chamber 406, the common supply flow path 409, the opening 441 of the cover plate 440, the supply flow path 431 of each discharge port row, and the inlet 421, and a part of the ink flows into the discharge port 402. Also, from the discharge port 402, ink passes through the flow path in the order of the outlet 422, the recovery flow path 432, the opening 441 of the cover plate 440, and the common recovery flow path 410, and is recovered into the second pressure control chamber 407. That is, the flow of ink in the chip 403 flows in the direction of the arrows shown in FIGS. 5 and 6. Note that the negative pressure and the ink flow velocity in the discharge port 402 are adjusted so as to be within a range capable of holding the meniscus. That is, by adjusting the flow rate of the circulation drive pump 408, the pressure loss of the flow path between the first pressure control chamber 406 and the second pressure control chamber 407, and the opening and closing force of the valve at the inlet, the negative pressure and the ink flow velocity in the discharge port 402 are adjusted.

[0041] As described above, by driving the circulation drive pump 408, a flow in which the ink near the discharge port 402 moves is generated, suppressing an increase in ink viscosity due to drying in the discharge port during the recording operation, and suppressing deterioration of the ink ejection characteristics.

[0042] <Composition of Ink> Next, the ink used in this embodiment will be described. Hereinafter, "parts" and "%" are based on mass unless otherwise specified.

[0043] (Black Ink) (1) Preparation of Pigment Dispersion Liquid First, an anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (polymerization ratio (weight ratio) = 30 / 40 / 30), acid value 202, weight average molecular weight 6500] was prepared. This was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10 mass% polymer aqueous solution.

[0044] 100 g of the above polymer solution, 100 g of carbon black, and 300 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hours. Next, using a microfluidizer, this mixture was processed by passing it through the interaction chamber 5 times under a liquid pressure of about 70 MPa. Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed matter containing coarse particles to obtain a black dispersion. The obtained black dispersion had a pigment concentration of 10 mass% and a dispersant concentration of 6 mass%.

[0045] (2) Preparation of resin fine particle dispersion First, under a nitrogen atmosphere, while heating to 70 °C and stirring with a motor, the following three additive solutions were added dropwise little by little and polymerization was carried out for 5 hours. Each additive solution is a mixed solution containing a hydrophobic monomer consisting of 28.5 parts of methyl methacrylate, a mixed solution containing a hydrophilic monomer consisting of 4.3 parts of sodium p-styrenesulfonate and 30 parts of water, and a polymerization initiator-containing mixed solution consisting of 0.05 parts of potassium persulfate and 30 parts of water.

[0046] (3) Preparation of ink For the preparation of the ink, the above black dispersion and the above resin fine particle dispersion were used. The following components were added thereto to a predetermined concentration, and after these components were sufficiently mixed and stirred, pressure filtration was carried out using a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink having a pigment concentration of 5 mass% and a dispersant concentration of 3 mass%.

[0047] 50 parts of the above black dispersion 10 parts of the above resin fine particle dispersion 15 parts of 2-methyl-1,3-propanediol 5 parts of 2-pyrrolidone 0.5 part of acetylene glycol EO adduct (manufactured by Kawaken Fine Chemicals Co., Ltd.) Ion-exchanged water, the balance

[0048] (cyan ink) (1) Preparation of dispersion liquid First, using benzyl acrylate and methacrylic acid as raw materials, an AB-type block polymer with an acid value of 250 and a number average molecular weight of 3000 was prepared by a conventional method, and then neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50 mass% polymer aqueous solution

[0049] 180 g of the above polymer solution, 100 g of C.I. Pigment Blue 15:3, and 220 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour

[0050] Next, using a microfluidizer, this mixture was processed by passing it through the interaction chamber 5 times under a liquid pressure of about 70 MPa

[0051] Furthermore, the dispersion liquid obtained above was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed matter containing coarse particles to obtain a cyan dispersion liquid. The obtained cyan dispersion liquid had a pigment concentration of 10 mass% and a dispersant concentration of 10 mass%

[0052] (2) Preparation of resin fine particle dispersion liquid A resin fine particle dispersion liquid was prepared by the same raw materials and preparation method as those described for the above cyan ink

[0053] (3) Preparation of ink For the preparation of the ink, the above cyan dispersion liquid was used, and the following components were added thereto to a predetermined concentration. Then, after these components were sufficiently mixed and stirred, pressure filtration was performed with a microfilter having a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink having a pigment concentration of 2 mass% and a dispersant concentration of 2 mass%

[0054] 20 parts of the above cyan dispersion liquid 10 parts of the above resin microparticle dispersion 15 parts of 2-methyl-1,3-propanediol 5 parts of 2-pyrrolidone 0.5 part of acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) The balance is ion-exchanged water.

[0055] (magenta ink) (1) Preparation of the dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB-type block polymer with an acid value of 300 and a number-average molecular weight of 2500 was prepared by a conventional method. Further, it was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50% by mass polymer aqueous solution.

[0056] 100 g of the above polymer solution, 100 g of C.I. Pigment Red 122, and 300 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour.

[0057] Next, using a microfluidizer, this mixture was processed by passing it through the interaction chamber 5 times under a liquid pressure of about 70 MPa.

[0058] Furthermore, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed matter containing coarse particles to obtain a magenta dispersion. The obtained magenta dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 5% by mass.

[0059] (2) Preparation of the resin microparticle dispersion A resin microparticle dispersion was prepared by the same raw materials and production method as those described for the cyan ink.

[0060] (3) Preparation of the ink The ink is prepared by using the above magenta dispersion liquid, adding the following components thereto to a predetermined concentration, and after sufficiently mixing and stirring these components, subjecting them to pressure filtration through a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink having a pigment concentration of 4% by mass and a dispersant concentration of 2% by mass.

[0061] 40 parts of the above magenta dispersion liquid 10 parts of the above resin fine particle dispersion liquid 15 parts of 2-methyl-1,3-propanediol 5 parts of 2-pyrrolidone 0.5 part of acetylene glycol EO adduct (manufactured by Kawaken Fine Chemicals Co., Ltd.) The balance is ion-exchanged water.

[0062] (Yellow Ink) (1) Preparation of dispersion liquid First, the anionic polymer P-1 was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer aqueous solution.

[0063] 30 parts of the above polymer solution, 10 parts of C.I. Pigment Yellow 74, and 60 parts of ion-exchanged water were mixed, charged into a batch vertical sand mill (manufactured by Aimex), filled with 150 parts of zirconia beads having a diameter of 0.3 mm, and subjected to a dispersion treatment for 12 hours while cooling with water.

[0064] Furthermore, the dispersion liquid obtained above was subjected to centrifugal separation treatment to remove non-dispersed substances containing coarse particles to obtain a yellow dispersion liquid. The obtained yellow dispersion liquid had a solid content of about 12.5% and a weight average particle diameter of 120 nm.

[0065] (2) Preparation of resin fine particle dispersion liquid A resin fine particle dispersion liquid was prepared by the same raw materials and production method as those described for the cyan ink.

[0066] (3) Preparation of ink The following components were mixed and stirred well until dissolved and dispersed, and then pressure filtered through a microfilter with a pore size of 1.0 μm (manufactured by Fujifilm Corporation) to prepare the ink.

[0067] 40 parts of the above yellow dispersion 10 parts of the above resin fine particle dispersion 15 parts of 2-methyl-1,3-propanediol 5 parts of 2-pyrrolidone 0.5 part of acetylene glycol EO adduct (manufactured by Kawaken Fine Chemicals Co., Ltd.) The balance is ion-exchanged water.

[0068] As a feature of the ink used in this embodiment, in order to fix the ink on a non-permeable recording medium, it contains "resin fine particles". "Resin fine particles" means fine particles made of resin and having a particle size that can be dispersed in an aqueous medium. The resin fine particles have a function of melting by heating and forming a film (film formation) on the surface of the recording medium, thereby fixing the pigment on the surface of the recording medium.

[0069] In the present disclosure, it is preferable that the glass transition point Tg of the resin constituting the resin fine particles is more than 30°C and less than 80°C. When it is 30°C or lower, the difference between the Tg of the resin and room temperature is small, and the resin fine particles are in a state close to the molten state even in the ink. Therefore, the viscosity of the ink increases in the head, and the quality of the image (color development, sharpness, etc.) may deteriorate due to poor ink ejection. When it is 80°C or higher, a large amount of heat is required by the heat drying means to melt the resin fine particles, and the resin fine particles cannot be melted before the aggregation of the pigment due to the evaporation of the moisture in the ink occurs, and the quality of the image (color development, etc.) may deteriorate.

[0070] The resin constituting the resin fine particles is not particularly limited as long as its glass transition temperature Tg satisfies the above range. Specifically, examples thereof include acrylic resin, styrene-acrylic resin, polyethylene resin, polypropylene resin, polyurethane resin, styrene-butadiene resin, and fluoroolefin resin. For example, acrylic resin can be synthesized by emulsion polymerization of monomers such as alkyl (meth)acrylate and alkyl (meth)acrylamide. Styrene-acrylic resin can also be synthesized by emulsion polymerization of monomers such as alkyl (meth)acrylate and alkyl (meth)acrylamide and styrene. By emulsion polymerization, an emulsion in which fine particles (resin fine particles) made of the above resin are dispersed in a medium can be obtained.

[0071] In the present disclosure, as the resin fine particles having a sulfonic acid group, those that are insoluble in water and made of any resin component generally used can be used. The resin component constituting the resin fine particles is not particularly limited as long as it is a resin containing a sulfonic acid group, and any resin component such as any generally used natural or synthetic polymer, or a polymer newly developed for the present disclosure can be used without limitation. In particular, from the viewpoint of general usability and easy functional design of resin fine particles, polymers or copolymers of monomer components having a radically polymerizable unsaturated bond, such as acrylic resin and styrene / acrylic resin, can be used.

[0072] Generally, surfactants are used as penetrants for the purpose of improving the penetrability of ink with respect to inkjet - dedicated recording media. In the case of non - penetrable recording media, they are used for the purpose of improving wettability. The greater the amount of surfactant added, the stronger the property of reducing the surface tension of the ink, and the better the wettability and penetrability of the ink with respect to the recording media. It is preferable to use surfactant acetylene glycol EO adducts or fluorine - based or silicone - based surfactants. Fluorine - based or silicone - based surfactants can reduce the surface tension of the ink even with a small content, so they can enhance the wettability of the ink with respect to the recording media. Thereby, even when recording on a non - absorbent recording media, the phenomenon that the ink bounces off the surface of the recording media is suppressed, and the image quality can be further improved. In the case of this embodiment, the surface tension of all inks is preferably adjusted to 30 dyn / cm or less. The surface tension was measured using a fully automatic surface tension meter CBVP - Z (manufactured by Kyowa Interface Science Co., Ltd.). Note that as long as the surface tension of the ink can be measured, the measuring instrument is not limited to the above - exemplified one.

[0073] Also, since all the inks of this embodiment use anionic colorants, the pH of the ink is stable on the alkaline side, and its value is 8.5 - 9.5. From the viewpoint of preventing the elution of impurities from the members in contact with the ink, the deterioration of the materials constituting the members, and the decrease in the solubility of the pigment - dispersing resin in the ink, generally, the pH of the ink is preferably 7.0 or more and 10.0 or less. The pH was measured using a pH METER model F - 52 manufactured by Horiba, Ltd. Note that as long as the pH of the ink can be measured, the measuring instrument is not limited to the above - exemplified one.

[0074] <Recovery operation and timing of preliminary ejection> In the recording apparatus 101 configured as described above, ink in the flow path (pressure chamber) passing through the nozzles is circulated during the recording operation. In this embodiment, a method and control for determining the timing of the recovery operation of the nozzle surface (discharge port surface) and preliminary discharge after the recording operation are described. Thereby, it is possible to suppress the thickened ink, foreign matter, and miscolored ink that have entered the nozzles during the execution of the recovery operation from flowing to the back of the circulation flow path, and it is possible to reduce the influence on the image and ink discharge performance. In addition, the time until the start of the recovery operation can be shortened, and it is possible to suppress a decrease in productivity.

[0075] FIG. 8 is a graph showing the ink flow velocity in the nozzle internal circulation flow path with respect to the elapsed time when circulation is stopped after the recording operation. The nozzle internal circulation flow path is the flow path passing through the pressure chamber 424. As described above, during the recording operation, the discharge characteristics are stabilized by circulating the ink in the nozzle, so the circulation drive pump 408 is driven. For simplicity of explanation, it is assumed that there is no ink discharge from the nozzle during the recording operation shown in FIG. 8, and a constant pressure difference is generated between the first pressure control chamber 406 and the second pressure control chamber 407, and the ink flow velocity is also constant. When the ink is discharged, the negative pressure in the first pressure control chamber 406 and the second pressure control chamber 407 temporarily increases, and the pressure difference also changes. However, as described above, when the valve 411 at the inlet of the first pressure control chamber 406 opens and ink is supplied from the ink tank 202 to the buffer tank 401, it returns to the original pressure state. For this reason, although the flow velocity can locally change in response to the ink discharge, in the description of FIG. 8, for simplicity of explanation, it is described as if there is no ink discharge. When the recording operation ends, under the control of the recording control unit 301, the recording head 110 returns to the standby position, and after the necessary recovery operation is performed by the recovery unit 210, it is capped.

[0076] When the recording head 110 returns to the standby position, the recording control unit 301 moves the wipers (the first wiper 221 and the second wiper 222) of the recovery unit 210 to the wiping start position. After the recording operation is completed, it is not necessary to circulate the ink in the nozzles to suppress the increase in viscosity due to evaporation. Therefore, the recording control unit 301 stops driving the circulation drive pump 408 at the timing of stopping the circulation drive shown in FIG. 8. However, immediately after the circulation flow rate of the ink due to the pump drive disappears, a pressure difference remains in the first pressure control chamber 406 and the second pressure control chamber 407. And since the valve 412 at the inlet of the second pressure control chamber 407 is open, the ink continues to flow for a certain period of time in the flow path between the pressure control chambers and the flow path passing through the nozzles. Since the pressure difference between the first pressure control chamber 406 and the second pressure control chamber 407 is gradually eliminated as the ink flows, the valve 412 closes, and the ink further flows through the nozzles, and accordingly the flow rate of the ink also decreases. And after a certain period of time, the flow of the ink almost stops.

[0077] When the time from the above-described circulation drive stop to the start of wiping is longer than the time from the circulation drive stop to the stop of the circulation flow rate, wiping is performed in a state where the circulation flow rate has stopped. For this reason, even if wiping is started, problems such as the thickened ink, foreign matter, and miscolored ink on the nozzle surface layer invading the back of the circulation flow path do not occur.

[0078] However, when wiping is started after waiting until the circulation flow rate stops, the start of the wiping operation is delayed by the waiting time, and accordingly the start of the recording operation of the next recorded image is also delayed. Therefore, the productivity of the recording apparatus 101 is reduced.

[0079] FIG. 9 is a diagram schematically showing wiping and preliminary ejection operations. FIG. 9(a) shows a comparative example in which wiping is performed without waiting for the circulation flow velocity to stop and preliminary ejection is carried out. In FIG. 9, as an example of the wiper, the first wiper 221 is illustrated. In FIG. 9(a), an example is shown in which preliminary ejection is being performed after the first wiper 221 has finished wiping the nozzle surface of the recording head 110 in the direction W. When wiping is performed without waiting for the circulation flow velocity to stop, as shown in FIG. 9(a), the thickened ink, foreign matter, and mixed-color ink are flowed by circulation to the depth of the circulation flow path (for example, the outlet 422). That is, the thickened ink and the like that have entered the nozzle (inside the ejection port 402 and the pressure chamber 424) due to the wiping operation are flowed by circulation to the depth of the circulation flow path (for example, the outlet 422). For this reason, even if preliminary ejection is performed after the wiping operation is completed, there is a possibility that the thickened ink, foreign matter, and mixed-color ink cannot be removed.

[0080] FIG. 9(b) shows an example of the wiping and preliminary ejection operations in the present embodiment. As shown in FIG. 9(b), in the present embodiment, preliminary ejection is performed from the nozzle for which the wiping operation has been completed. That is, before the first wiper 221 finishes wiping all the ejection ports 402 (nozzles), preliminary ejection is performed from the nozzle for which the wiping operation has been completed. In other words, control is performed so that the preliminary ejection of each nozzle is carried out at different timings. By performing preliminary ejection from the nozzle for which the wiping operation has been completed, that is, by performing the wiping operation and the preliminary ejection in parallel, it is possible to suppress the thickened ink, foreign matter, and mixed-color ink that have entered the nozzle from flowing to the depth of the circulation path. As a result, it is possible to reduce the influence on the image and the ink ejection performance.

[0081] However, when wiping is performed without waiting for the circulation flow rate to stop after the circulation drive is stopped, the circulation flow rate is in a state of being lower than during the image recording operation on the recording medium 103. Therefore, if preliminary ejection is performed at a timing when the circulation flow rate falls below the circulation flow rate at which ink can be ejected, ejection may not be possible, and there is a possibility that the thickened ink, foreign matter, and mixed-color ink cannot be eliminated. If the circulation flow rate at which ink can be ejected drops even slightly, nozzles that become unable to eject may occur due to the influence of thickening or the like. Therefore, the circulation flow rate at which ink can be ejected can also be said to be a circulation flow rate such that the thickened ink does not clog the ejection port.

[0082] Thus, in order to avoid the inability to eject when preliminary ejection is performed at a timing when the circulation flow rate at which ink can be ejected is exceeded, the following method is implemented in the present embodiment.

[0083] FIG. 10 is a diagram showing the recovery operation (wiping operation) and the preliminary ejection execution period in the present embodiment. As shown in FIG. 10(a), the wiping and preliminary ejection operations are completed within a time range in which the circulation flow rate of the recording head 110 is equal to or higher than the circulation flow rate v1 at which ink can be ejected. Thereby, since preliminary ejection can be appropriately performed, it is possible to suppress the thickened ink, foreign matter, and mixed-color ink that have entered the nozzles from flowing to the back of the circulation path. Therefore, it is possible to reduce the influence on the image and the ink ejection performance.

[0084] Furthermore, in this embodiment, although the case where the circulation drive is stopped after the image recording operation on the recording medium 103 is completed has been described as an example, the present invention is not limited to this example. For example, there may be a case where the wiping and preliminary ejection operations cannot be completed within the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate v1 at which ink ejection is possible, from the stop of the circulation drive. In such a case, for example, as shown in FIG. 10(b), the rotation speed of the circulation drive pump 408 is decelerated. By decelerating the rotation speed of the circulation drive pump 408, the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate v1 at which ink ejection is possible can be extended. Therefore, the wiping and preliminary ejection operations can be completed within the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate at which ink ejection is possible, from the stop of the circulation drive.

[0085] Furthermore, the method for dealing with the case where the wiping and preliminary ejection operations cannot be completed within the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate v1 at which ink ejection is possible, from the stop of the circulation drive, is not limited to the example of decelerating the rotation speed of the circulation drive pump 408.

[0086] FIG. 11 is a diagram showing another example of the recovery operation and the preliminary ejection execution period in the present embodiment. As shown in FIG. 11, after the image recording operation on the recording medium 103 is completed, the wiping operation and the preliminary ejection operation are performed without stopping the circulation drive. By stopping the circulation drive after starting the wiping, it is also possible to control the wiping and preliminary ejection operations to be completed within the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate v1 at which ink ejection is possible. Also, in the example shown in FIG. 11, as shown in FIG. 9(b), preliminary ejection is performed from the nozzles where the wiping operation has been completed.

[0087] As yet another example, in the case where the wiping and preliminary ejection operations cannot be completed within the time range in which the circulation flow rate of the recording head 110 becomes equal to or higher than the circulation flow rate v1 at which ink ejection is possible, from the stop of the circulation drive, control may be performed to increase the ejection frequency in the preliminary ejection. Thereby, it becomes possible to shorten the required time for the preliminary ejection.

[0088] Furthermore, by combining the examples described above, the wiping and preliminary ejection operations can be completed within the time range from when the circulation drive is stopped until the circulation flow velocity of the recording head 110 becomes equal to or greater than the circulation flow velocity v1 at which ink can be ejected.

[0089] FIG. 12 shows a flowchart of the control of performing preliminary ejection from nozzles for which wiping operation has been completed after the end of the recording operation in this embodiment. The process shown in FIG. 12 is performed by the recording control unit 301 of the recording device 101. That is, the CPU 302 of the recording control unit 301 reads a program stored in the memory 303 or an external storage device, and the CPU 302 executes the program, thereby realizing the process. Note that some or all of the functions of the steps in FIG. 12 may be realized by hardware such as ASIC or electronic circuits. The symbol "S" in the description of each process means a step in the flowchart (the same applies to the flowcharts in the following specification). The process shown in FIG. 12 is a process that is performed when it is determined that a recovery operation is necessary during circulation driving. In this embodiment, the time required for both the recovery operation and the preliminary ejection to be completed is described as T1. T1 may be a value obtained by actually performing preliminary ejection from nozzles for which wiping has been completed, or may be a value derived using the wiping movement speed and the preliminary ejection time.

[0090] In S1201, the recording control unit 301 obtains a time T2 during which recording is possible without impairing the ejection characteristics from the circulation drive stop timing. To obtain the time T2, the recording control unit 301 obtains a circulation flow velocity v1 at which ink can be ejected. The circulation flow velocity v1 at which ink can be ejected varies depending on the type of ink and the recording operation mode, etc. For example, when the recording operation mode is the high-quality mode, the circulation flow velocity v1 at which ink can be ejected is faster than in the standard mode or the high-speed mode. In the case of the high-quality mode, the amount of ink ejected per unit time onto the recording medium is larger than in the standard mode or the high-speed mode. Therefore, the speed (circulation flow velocity) required to supply fresh ink to the nozzles again is faster in the high-quality mode than in the standard mode or the high-speed mode.

[0091] Thus, based on the ink and the recording operation mode, the circulation flow velocity v1 at which ink can be ejected (hereinafter also referred to as the required flow velocity) varies. Therefore, the recording control unit 301 obtains the value of v1 from, for example, the required flow velocity table shown in FIG. 13.

[0092] FIG. 13 is a diagram showing a required flow velocity table. FIG. 14 is a diagram showing a flow velocity prediction table. The required flow velocity table shown in FIG. 13 and the flow velocity prediction table shown in FIG. 14 are stored, for example, in the memory 303 or an external storage device.

[0093] For example, when the ink to be determined is cyan (C) and the recording operation mode is the standard image quality mode, the recording control unit 301 refers to the table shown in FIG. 13 and determines that a flow velocity of 3 mm / s is required. Subsequently, the recording control unit 301 obtains the circulation flow velocity with respect to the elapsed time from the circulation drive stop using the flow velocity prediction table shown in FIG. 14. In the table of FIG. 14, the time T2 (cyan) during which the cyan ink maintains a flow velocity of 3 mm / s or more after the circulation drive stop is 10 seconds.

[0094] In S1202, the recording control unit 301 compares T1 and T2 acquired (determined) as described above, and determines whether the recovery operation and the preliminary discharge operation can be completed. That is, the recording control unit 301 determines whether T1 < T2. If T1 < T2, even if the circulation drive pump 408 is stopped, the discharge characteristics will not be impaired until the recovery operation and the preliminary discharge operation are completed. Therefore, the recording control unit 301 proceeds to S1203. On the other hand, if T1 < T2 is not satisfied, if the circulation drive pump 408 is stopped, the discharge characteristics will be impaired until the recovery operation and the preliminary discharge operation are completed. Therefore, when T1 < T2 is not satisfied, the recording control unit 301 proceeds to S1208. Note that since T2 varies depending on the ink, the determination in S1202 is performed for each ink. That is, depending on the ink, there are cases where the process proceeds to S1203 and cases where the process proceeds to S1208. Note that the wiping process described later is a process of wiping the entire nozzles of the recording head 110 together without individually wiping the nozzles for each ink. That is, although the stop timing of the circulation drive pump 408 may vary depending on the ink, in the present embodiment, it is assumed that the time required until the recovery operation and the preliminary discharge operation are completed is common for each ink. Note that the time required for the preliminary discharge operation may also vary depending on the ink. In such a case, the time required until the recovery operation and the preliminary discharge operation are completed may be stored for each ink, and that time may be used as T1. That is, it may be a process of acquiring T1 for each ink.

[0095] In S1203, the recording control unit 301 stops the circulation drive by the circulation drive pump 408. Next, in S1204, the recording control unit 301 starts the wiping operation. Then, in S1205, the recording control unit 301 acquires the wiper position with respect to the nozzle position during the wiping operation. The acquisition of the wiper position can be derived, for example, from the elapsed time since the start of wiping and the wiping speed. Also, the recording control unit 301 can manage the wiper position based on the count information obtained by the encoder sensor corresponding to the recovery unit motor 206 that operates the wiper counting the slits. That is, the wiper position can also be obtained from the sensor information. Note that any method may be used as long as the wiper position with respect to the nozzle position during the wiping operation can be obtained.

[0096] Next, in S1206, the recording control unit 301 determines the nozzles passed by the first wiper 221 and the second wiper 222 as the nozzles to start the preliminary discharge. Then, at the determined nozzles, the preliminary discharge is performed. That is, the recording control unit 301 discharges ink from the energy generating element 423 corresponding to the determined nozzles (discharge ports).

[0097] Next, in S1207, the recording control unit 301 determines whether the wiping and the preliminary discharge are completed. If it is determined that the wiping and the preliminary discharge are completed, the recording control unit 301 ends the process shown in FIG. 12. If it is determined that the wiping and the preliminary discharge are not completed, the recording control unit 301 returns to S1205 and repeats the process. In this way, by repeating the acquisition of the wiper position and the preliminary discharge operation of the nozzles passed by the wiper, the preliminary discharge operation is sequentially started from the nozzles where the wiping is completed. That is, the parallel operation of wiping and preliminary discharge is performed.

[0098] Next, the process when it is determined in S1202 that T1 < T2 is not satisfied will be described. In S1208, the recording control unit 301 performs the process of stopping the circulation drive after starting the recovery operation. Then, the recording control unit 301 ends the process shown in FIG. 12.

[0099] FIG. 15 is a flowchart showing the detailed processing of S1208. In S1501, the recording control unit 301 determines whether to decelerate the rotational speed of the circulation drive pump 408. The determination in S1501 may be made based on the preset content or by a designation from the user. If it is determined to decelerate the rotational speed of the circulation drive pump 408, the recording control unit 301 proceeds to S1502. In S1502, the recording control unit 301 decelerates the rotational speed of the circulation drive pump 408. Then, it proceeds to S1503. If it is not determined to decelerate the rotational speed of the circulation drive pump 408, the recording control unit 301 proceeds to S1503.

[0100] The processing from S1503 to S1505 is the same as the processing from S1204 to S1206, so the description is omitted. In S1506, the recording control unit 301 determines whether to stop the circulation drive pump 408. For example, when it is determined that T1 < T2 does not hold, the recording control unit 301 can identify the time when T1 < T2 by adding a predetermined time to T2. When the predetermined time has elapsed, the recording control unit 301 determines to stop the circulation drive pump 408. Also, even when the rotational speed is being decelerated, similarly, since the circulation operation becomes unnecessary at the time of recording stop, when the time when T1 < T2 is reached at the original rotational speed, the recording control unit 301 may determine to stop the circulation drive pump 408.

[0101] If it is determined in S1506 to stop the circulation drive pump 408, it proceeds to S1507. In S1507, the recording control unit 301 stops the circulation drive pump 408. Then, it proceeds to S1508. If it is not determined in S1506 to stop the circulation drive pump 408, the recording control unit 301 proceeds to S1508. The processing in S1508 is the same as the processing in S1207, so the description is omitted.

[0102] Still, as described above, wiping is performed in common for each ink. Therefore, for example, even when inks with T1 < T2 and inks with T1 ≥ T2 are mixed, the processes for starting the wiping operation in S1204 and S1503 are processes at the same timing. Of course, if wiping is performed individually for each nozzle of the ink, the processes for starting the wiping operation in S1204 and S1503 do not have to be processes at the same timing. Also, as described above, the control for increasing the ejection frequency in the preliminary ejection may be a process combined with the flowchart shown in FIG. 12 or FIG. 15.

[0103] As described above, according to the present embodiment, it is possible to suppress the entry of foreign substances and the like into the flow path during the recovery operation. Also, it is possible to suppress a decrease in productivity. That is, in the present embodiment, wiping and preliminary ejection operations are performed in parallel. Thereby, before wiping is completed for all nozzles, preliminary ejection is performed from the nozzles for which wiping has been completed, so that it is possible to suppress a decrease in productivity while suppressing the entry of mixed-color ink or foreign substances into the flow path during the recovery operation. In particular, in a recording head in which the nozzle row is lengthened, the time required for wiping all nozzles tends to increase. By performing wiping and preliminary ejection operations in parallel as in the present embodiment, a decrease in productivity can be suppressed.

[0104] Also, in the present embodiment, it is configured to complete the wiping and preliminary ejection operations within a time range in which the circulation flow velocity of the recording head 110 becomes equal to or higher than the circulation flow velocity v1 at which ink can be ejected from the stop of the circulation drive of each ink. Therefore, it is possible to suppress the influence on the recorded image after the circulation drive is stopped and suppress the entry of thickened ink, foreign substances, and mixed-color ink into the flow path during wiping.

[0105] <<Second Embodiment>> In this embodiment, an example will be described in which when the ink in the flow path (pressure chamber) passing through the nozzles is circulated during the recording operation and the recovery operation of the discharge port surface is executed after the recording operation is completed, the preliminary discharge amount is determined according to the circulation flow velocity at the time of performing the preliminary discharge. As a result, it is possible to reduce the range of intrusion of the thickened ink, foreign matter, and mixed-color ink into the flow path during wiping, and facilitate the discharge by the preliminary discharge. Since the basic configuration is the same as the example described in the first embodiment, the description will focus on the differences.

[0106] FIG. 16 is a diagram showing the change over time of the circulation flow velocity after the circulation drive pump is stopped. The horizontal axis represents the elapsed time since the circulation drive pump was stopped. The vertical axis represents the circulation flow velocity. When the circulation drive is stopped after the image recording operation on the recording medium 103 is completed, immediately after the circulation flow velocity of the ink by the pump drive disappears, a pressure difference remains in the first pressure control chamber 406 and the second pressure control chamber 407. And since the valve 412 at the inlet of the second pressure control chamber 407 is open, in the flow path between the pressure control chambers and the flow path passing through the nozzles, for a certain period of time, the ink continues to flow while the flow velocity of the ink gradually decreases. If the recovery operation of the discharge port surface is performed in this state, as described above, the thickened ink, foreign matter, and mixed-color ink pushed into the nozzles may penetrate deeper into the circulation flow path.

[0107] Here, the thickened ink, foreign matter, and mixed-color ink that have entered the nozzles have different progress ranges and progress speeds into the flow path according to the circulation flow velocity. FIG. 16 shows that the higher the circulation flow velocity, the faster the progress speed of the thickened ink into the circulation flow path, but the progress range of the thickened ink from the corresponding nozzle becomes narrower. Also, as the circulation flow velocity decreases, the progress speed of the thickened ink slows down, and the progress range of the thickened ink from the corresponding nozzle becomes wider.

[0108] Generally, the higher the flow velocity, the farther the thickening ink flows to the back of the downstream of the flow path. In that case, it is necessary to increase the preliminary discharge amount. However, in the example of FIG. 16, the transition of the flow velocity decrease after the circulation drive is stopped is shown. In this aspect of the flow velocity decrease, by determining the preliminary discharge amount based on the progress range, it is possible to suppress the progress of the thickening ink over a wide range, and thus suppress the progress of the thickening ink as a whole. The progress range and the required preliminary discharge amount have a correlation as shown in FIG. 16. Therefore, in the present embodiment, from the perspective of the progress range, when the circulation flow velocity after the circulation drive is stopped is high, since the progress range is small, it is configured to reduce the preliminary discharge amount. Hereinafter, an example of determining the preliminary discharge amount according to the circulation flow velocity at the time of performing the preliminary discharge will be described.

[0109] FIG. 17 is a diagram showing a flowchart of control for performing preliminary discharge from a nozzle for which a wiping operation has been completed after the recording operation in the present embodiment. The process shown in FIG. 17 is a process performed by the recording control unit 301 of the recording apparatus 101, similar to the example described with reference to FIG. 12. Further, the process shown in FIG. 17 is a process performed on the occasion of determining that a recovery operation is required in the state during the circulation drive, similar to the example described with reference to FIG. 12. Also in the present embodiment, the required time required until both the recovery operation and the preliminary discharge are completed is described as T1.

[0110] The processes from S1701 to S1704 are the same as the processes from S1201 to S1204 in FIG. 12. That is, when T1 < T2, since the discharge characteristics are not impaired until the end of the recording operation even if the circulation drive pump 408 is stopped, the recording control unit 301 stops the circulation drive by the circulation drive pump 408 in S1703 and starts the wiping operation in S1704.

[0111] Next, in the same manner as the example described in the first embodiment, in S1705, the recording control unit 301 acquires the wiper position with respect to the nozzle position during the wiping operation. Note that the method for acquiring the wiper position is the same as the example described in the first embodiment. In this embodiment, in parallel with the process of S1705, in S1706, the recording control unit 301 acquires the current circulation flow velocity v2. The current circulation flow velocity v2 can be derived based on the required flow velocity table shown in FIGS. 13 and 14 and the predicted circulation flow velocity table with respect to the elapsed time from the circulation stop.

[0112] Next, in S1707, the recording control unit 301 determines a preliminary discharge amount according to the current circulation flow velocity v2 acquired in S1706. Subsequently, in S1708, the recording control unit 301 determines the nozzles (discharge ports) passed by the first wiper 221 and the second wiper 222 as the nozzles at which to start the preliminary discharge, and starts the preliminary discharge at those nozzles. In the preliminary discharge performed in S1708, the preliminary discharge amount is the preliminary discharge amount of the relationship shown in FIG. 16. In the circulation flow velocity v2 shown in FIG. 16, it is shown that the preliminary discharge amount is A. Actually, a table defining the number of discharge times per nozzle corresponding to A to D is stored in advance in the memory 303, and the recording control unit 301 may control the preliminary discharge amount by referring to this table. Also, the required preliminary discharge amount varies depending on the configuration of the ink and the recording head, etc. For this reason, for example, by checking the preliminary discharge amount that can discharge the thickened ink, foreign matter, and miscolored ink that have entered the circulation flow path by wiping, the preliminary discharge amount defined in the table can be determined. Note that, as a method for checking whether the thickened ink, foreign matter, and miscolored ink have been discharged by the preliminary discharge, for example, it may be checked whether the image recorded on the recording medium has the desired density and color tone.

[0113] Since S1709 is the same process as S1207, the description thereof is omitted. Also, when it is determined in S1702 that T1 < T2, the recording control unit 301 proceeds to S1710.

[0114] FIG. 18 is a flowchart showing details of S1710. The processes from S1801 to S1803 are the same as the processes from S1501 to S1503 in FIG. 15. Also, the processes from S1804 to S1807 are the same as the processes from S1705 to S1708. Further, the processes from S1808 to S1810 are the same as the processes from S1506 to S1508. Thus, even when the driving of the circulation drive pump 408 is stopped after starting the recovery operation, the process of determining the preliminary discharge amount based on the circulation flow velocity at the time of performing the preliminary discharge is performed.

[0115] As described above, according to the present embodiment, by determining the preliminary discharge amount according to the circulation flow velocity at the time of performing the preliminary discharge, it is possible to reduce the intrusion range of the thickened ink, foreign matter, and mixed-color ink into the flow path during wiping. Further, it is possible to facilitate the discharge by the preliminary discharge while reducing the amount of waste ink required for the preliminary discharge.

[0116] <<Third Embodiment>> In the first and second embodiments, an example of control for determining the nozzles for which the wiping operation has been completed and performing preliminary discharge at those nozzles has been described. In the present embodiment, an example of determining that the wiping has been completed in area units and performing preliminary discharge at the nozzles in the corresponding area will be described. Since the basic configuration and the like are the same as the examples described in the first or second embodiment, the description will be omitted.

[0117] FIG. 19 is a diagram showing an example of a wiping area. Depending on the type of the recording head 110, it may be difficult to control the start of pre-discharge in each nozzle unit through which the first wiper 221 and the second wiper pass. In the present embodiment, in such a case, all the nozzles on the discharge port surface are divided into areas of a predetermined nozzle unit. The example of FIG. 19 shows an example of dividing into three areas: a first area, a second area, and a third area. For example, when the first wiper 221 and the second wiper 222 pass through the first area and start wiping in the second area, the recording control unit 301 performs pre-discharge at the nozzles in the first area. Note that in the present embodiment, an example of dividing the area into three is used for explanation, but it may be divided into two or more areas.

[0118] As described above, according to the present embodiment, even when it is not possible to manage the completion of wiping for each nozzle, it is possible to suppress a decrease in productivity and suppress the mixing of mixed-color ink or foreign matter into the flow path during the recovery operation.

[0119] <<Fourth Embodiment>> In the second embodiment, an example of controlling the pre-discharge amount according to the circulation flow velocity at the time of performing the pre-discharge was described. In the present embodiment, an example of controlling the pre-discharge amount for each nozzle according to the flow path configuration of the nozzle will be described. Since the basic configuration is the same as the example described in the first embodiment, the description will focus on the differences. Further, the present embodiment may be combined with the examples described in the second embodiment or the third embodiment.

[0120] In the example described with reference to FIG. 7, on both sides of the nozzle, there are formed an inlet 421 for allowing ink to flow into the discharge port 402 and the pressure chamber 424, and an outlet 422 for allowing ink to flow out from the discharge port 402 and the pressure chamber 424. The inlet 421 and the outlet 422 also form a flow path. In the example of FIG. 7, the inlet 421 and the outlet 422 are arranged such that there is one for each two nozzles. However, for example, when one inlet 421 and one outlet 422 are arranged for each of more than two nozzles, in the nozzles close to the outlet 422, it is necessary to discharge, including the thickened ink that has entered the recovery flow path 432 connected to the outlet 422, etc., by preliminary discharge.

[0121] In the present embodiment, an example will be described in which the range of intrusion of thickened ink, foreign matter, and miscolored ink into the flow path during wiping is reduced by increasing the preliminary discharge amount for the nozzles closer to the outlet 422.

[0122] FIG. 20 is a diagram for explaining the control of the preliminary discharge amount for each nozzle according to the flow path configuration of the nozzle in the present embodiment. FIG. 20 shows an example in which three outlets 422 are provided with respect to the entire length of the arrangement portion where the discharge ports 402 are arranged. And in FIG. 20, it is shown that the preliminary discharge amount is controlled to increase for the nozzles closer to the outlet 422.

[0123] As described above, according to the present embodiment, it is possible to reduce the range of intrusion of thickened ink, foreign matter, and miscolored ink into the flow path during wiping, reduce the amount of waste ink required for preliminary discharge, and facilitate discharge by preliminary discharge.

[0124] In addition, also in the present embodiment, as in the example described in the third embodiment, an area where preliminary discharge is performed may be set according to the flow path configuration. For example, an area corresponding to the number of outlets 422 arranged corresponding to the number of discharge ports 402 (nozzles) may be set, and preliminary discharge may be started in units of areas where wiping has been completed.

[0125] <<Other Embodiments>> In addition, in each of the above-described embodiments, the form in which the circulation drive pump 408 is included in the recording head 110 has been described as an example. However, the circulation drive pump may be provided outside the recording head, that is, on the main body side. In any form, if it takes a predetermined time from when the drive of the circulation drive pump is stopped until the circulation in the circulation flow path stops, each of the above-described embodiments is useful.

[0126] In addition, in each of the above-described embodiments, an example in which the ink flows even after the circulation drive pump 408 is stopped due to the pressure difference between the two pressure control chambers has been described. However, the present invention is not limited to this example. The above-described embodiments are applicable to any form as long as the movement of the ink does not stop immediately after the circulation drive pump 408 is stopped and the ink can flow.

[0127] In addition, in the above-described embodiments, as an example of the recovery operation, the wiping operation using the first wiper 221 and the second wiper 222 has been described as an example. However, the recovery operation is not limited to this example. For example, a recovery operation in which wiping is performed while sucking using a suction wiper may be used. In addition, any recovery operation may be used as long as the recovery operation is performed in the longitudinal direction of the recording head.

[0128] The present invention 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 the 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.

[0129] The disclosure of the present embodiment includes configurations typified by the following examples of a recording apparatus and a control method of the recording apparatus.

[0130] <Configuration 1> A liquid discharge head having a discharge port for discharging a liquid, Circulation means for circulating the liquid in the liquid ejection head so as to pass through a pressure chamber communicating with the ejection port, Recovery means for performing a recovery operation of the liquid ejection head at a circulation flow rate slower than the circulation flow rate by the circulation means when an image is recorded on a recording medium by the liquid ejection head, Control means for controlling to perform preliminary ejection of discharging liquid not used for recording from the ejection port in parallel with the recovery operation by the recovery means, A liquid ejection apparatus, comprising:

[0131] <Configuration 2> The liquid ejection apparatus according to Configuration 1, wherein the control means performs the preliminary ejection from the ejection port where the recovery operation has been completed.

[0132] <Configuration 3> The liquid ejection apparatus according to Configuration 1 or 2, wherein the control means stops the circulation means and then performs the recovery operation after the recording operation on the recording medium is completed.

[0133] <Configuration 4> The liquid ejection apparatus according to Configuration 1 or 2, wherein the control means performs the recovery operation while decelerating the rotation speed of the pump in the circulation means after the recording operation on the recording medium is completed.

[0134] <Configuration 5> The liquid ejection apparatus according to Configuration 3 or 4, wherein the control means completes the recovery operation and the preliminary ejection within a time range in which the liquid ejection head has a circulation flow rate or more at which liquid can be ejected.

[0135] <Configuration 6> The liquid ejection apparatus according to Configuration 3 or 4, wherein when the recovery operation and the preliminary ejection are not completed within a time range in which the liquid ejection head has a circulation flow rate or more at which liquid can be ejected, after the recording operation on the recording medium is completed and after the start of the recovery operation, the control means stops the circulation means.

[0136] <Configuration 7> The liquid discharge device according to Configuration 3 or 4, wherein the control means increases the discharge frequency of the preliminary discharge when the preliminary discharge is not completed within a time range in which the liquid discharge head can discharge liquid at a circulation flow rate or higher.

[0137] <Configuration 8> Further comprising deriving means for deriving a circulation flow rate, The liquid discharge device according to any one of Configurations 1 to 7, wherein the control means determines the amount of the preliminary discharge based on the circulation flow rate derived by the deriving means at the time of performing the preliminary discharge.

[0138] <Configuration 9> The liquid discharge device according to Configuration 8, wherein the control means reduces the amount of the preliminary discharge as the circulation flow rate after stopping the circulation means is higher.

[0139] <Configuration 10> The liquid discharge device according to any one of Configurations 1 to 9, wherein the control means performs the control for each area constituted by a predetermined number of discharge ports.

[0140] <Configuration 11> The liquid discharge head has an inlet through which liquid flows into the discharge port and an outlet through which liquid flows out through the discharge port, The liquid discharge device according to any one of Configurations 1 to 10, wherein the control means determines the amount of the preliminary discharge based on the position of the outlet and the position of the discharge port.

[0141] <Configuration 12> The liquid discharge device according to Configuration 11, wherein the control means increases the amount of the preliminary discharge for discharge ports closer to the position of the outlet.

[0142] <Configuration 13> The liquid ejection head includes a first pressure control chamber connected to a first flow path communicating with the ejection port, and a second pressure control chamber connected to a second flow path communicating with the ejection port, The liquid ejection apparatus according to any one of Configurations 1 to 12, wherein liquid circulates through the ejection port according to a pressure difference between the first pressure control chamber and the second pressure control chamber.

[0143] <Configuration 14> The recovery means is a wiper that wipes the ejection port surface provided with the ejection port, The liquid ejection apparatus according to any one of Configurations 1 to 13, wherein the recovery operation is an operation of wiping the ejection port surface.

[0144] <Configuration 15> A liquid ejection head having an ejection port for ejecting liquid, Circulation means for circulating the liquid in the liquid ejection head so as to pass through a pressure chamber communicating with the ejection port, Recovery means for performing a recovery operation of the liquid ejection head at a circulation flow rate slower than the circulation flow rate by the circulation means when an image is recorded on a recording medium by the liquid ejection head, A control method for a liquid ejection apparatus having: Executing the recovery operation by the recovery means; A control method for a liquid ejection apparatus, comprising: controlling to perform a preliminary ejection of ejecting liquid not used for recording from the ejection port in parallel with the recovery operation by the recovery means.

Description of Reference Numerals

[0145] 110 Liquid ejection head 210 Recovery unit 301 Recording control unit 402 Ejection port 424 Pressure chamber

Claims

1. A liquid discharge head having a discharge port for discharging a liquid, Circulation means for circulating the liquid in the liquid discharge head so as to pass through a pressure chamber communicating with the discharge port, Recovery means for performing a recovery operation of the liquid discharge head at a circulation flow rate slower than the circulation flow rate by the circulation means when an image is recorded on a recording medium by the liquid discharge head, Control means for controlling to perform preliminary discharge for discharging liquid not used for recording from the discharge port in parallel with the recovery operation by the recovery means, A liquid discharge apparatus, comprising the above.

2. The liquid discharge apparatus according to claim 1, wherein the control means performs the preliminary discharge from the discharge port where the recovery operation has been completed.

3. The liquid discharge apparatus according to claim 1, wherein the control means performs the recovery operation after stopping the circulation means after the recording operation on the recording medium has been completed.

4. The liquid discharge apparatus according to claim 1, wherein the control means performs the recovery operation while decelerating the rotational speed of the pump in the circulation means after the recording operation on the recording medium has been completed.

5. The liquid discharge apparatus according to claim 3, wherein the control means completes the recovery operation and the preliminary discharge within a time range in which the circulation flow rate is equal to or higher than the circulation flow rate at which the liquid discharge head can discharge liquid.

6. The liquid discharge apparatus according to claim 3, wherein when the recovery operation and the preliminary discharge are not completed within a time range in which the circulation flow rate is equal to or higher than the circulation flow rate at which the liquid discharge head can discharge liquid, after the recording operation on the recording medium has been completed and after the start of the recovery operation, the control means stops the circulation means.

7. The liquid discharge apparatus according to claim 3, wherein when the preliminary discharge is not completed within a time range in which the circulation flow rate is equal to or higher than the circulation flow rate at which the liquid discharge head can discharge liquid, the control means increases the discharge frequency of the preliminary discharge.

8. Further comprising derivation means for deriving a circulation flow rate, The liquid discharge apparatus according to claim 1, wherein the control means determines the amount of the preliminary discharge based on the circulation flow rate derived by the derivation means at the time of performing the preliminary discharge.

9. The liquid discharge apparatus according to claim 8, wherein the faster the circulation flow rate after the circulation means is stopped, the smaller the amount of the preliminary discharge.

10. The liquid ejection apparatus according to claim 1, wherein the control means performs the control for each area constituted by a predetermined number of ejection ports.

11. The liquid ejection head has an inlet through which liquid flows into the ejection port and an outlet through which liquid flows out through the ejection port. The liquid ejection apparatus according to claim 1, wherein the control means determines the amount of preliminary ejection based on the position of the outlet and the position of the ejection port.

12. The liquid ejection apparatus according to claim 11, wherein the control means increases the amount of preliminary ejection for ejection ports closer to the position of the outlet.

13. The liquid ejection head includes a first pressure control chamber connected to a first flow path communicating with the ejection port and a second pressure control chamber connected to a second flow path communicating with the ejection port. The liquid ejection apparatus according to any one of claims 1 to 12, wherein liquid circulates through the ejection port in response to a pressure difference between the first pressure control chamber and the second pressure control chamber.

14. The recovery means is a wiper that wipes the ejection port surface provided with the ejection port. The liquid ejection apparatus according to claim 1, wherein the recovery operation is an operation of wiping the ejection port surface.

15. A liquid ejection head having an ejection port for ejecting liquid, Circulation means for circulating the liquid in the liquid ejection head so as to pass through a pressure chamber communicating with the ejection port, Recovery means for performing a recovery operation of the liquid ejection head at a circulation flow rate slower than the circulation flow rate by the circulation means when an image is recorded on a recording medium by the liquid ejection head, A control method for a liquid ejection apparatus having: Executing a step of performing the recovery operation by the recovery means; A control method for a liquid ejection apparatus, comprising a step of performing control to perform preliminary ejection of ejecting liquid not used for recording from the ejection port in parallel with the recovery operation by the recovery means.

Images