JP2024010457A - Recording device, control method of recording device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of properly and efficiently performing preliminary discharge executed correspondingly to a wiping operation to a discharge port surface of a recording head.

SOLUTION: A recording device 100 comprises: discharge means 423 which performs preliminary discharge of discharging ink from a discharge port 424 for recovering a discharge performance of the discharge port 424 of a recording head 110; and circulation means 408 which circulates ink in a flow channel communicating to the discharge port 424. The recording device 100 further includes: wiping means 530 which performs a wiping operation of a discharge port surface F; acquisition means 302 which acquires a flow rate of ink in the flow channel in the start of the wiping operation; and control means 302 which controls preliminary discharge on the basis of the flow rate acquired by the acquisition means 302.

SELECTED DRAWING: Figure 12

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a printing apparatus that performs printing by ejecting ink, a printing method for the printing apparatus, and a program.

In a printing device that performs printing by ejecting ink from the ejection ports of a print head, ink may adhere to the ejection port surface where the ejection ports are formed, and ink may increase within the ejection ports or the flow paths communicating with the ejection ports. Viscosity and the like are factors that reduce ink ejection performance. For this reason, a wiping process for wiping away ink adhering to the ejection port surface, and a process for discharging thickened ink and the like generated within the ejection port and the flow path are performed. Furthermore, in recent years, systems have been implemented in which ink in a flow path communicating with an ejection port is forcibly circulated by a pump to constantly supply ink in a state suitable for ejection to the flow path and the ejection port.

Patent Document 1 discloses a recording apparatus that implements a system that circulates ink. Further, Patent Document 1 discloses a configuration that performs the above-mentioned wiping process and discharge process (preliminary discharge). In the wiping process, ink adhering to the ejection port surface is wiped away by sliding a wiper against the ejection port surface. After this wiping process, preliminary ejection is performed to eject ink from the ejection ports. Preliminary ejection is also called purge ejection, and ink is ejected from the ejection port regardless of image data by driving an ejection element such as a heater provided opposite the ejection port. Thereby, ink unsuitable for ejection that has entered the ejection port due to wiping processing or the like can be ejected.

JP 2019-14152 Publication

In a recording device equipped with a system for flowing or circulating ink, such as the recording device disclosed in Patent Document 1, ink that is not suitable for ejection is forced into the ejection port by the wiping process, and then is carried away by the flowing ink. You may be swept away to the back of the road. If ink unsuitable for ejection is accumulated at the back of the flow path, image formation may be hindered. For example, if the ink that enters from the ejection port is a different color ink, there is a risk that color mixing will occur in the ink and a variation in color tone will occur in the formed image. Furthermore, there is a possibility that the flow of ink within the flow path may be inhibited. For this reason, in purge ejection performed after the wiping process, a large amount of ink is always ejected, assuming the maximum amount of ink that will enter the flow path from the ejection port. However, the amount of ink that enters the flow path from the ejection port varies depending on the flow rate of the ink within the flow path, and the flow speed of the ink within the flow path is not necessarily constant. Therefore, if a large amount of ink is uniformly discharged during purge discharge after the wiping process, there is a possibility that ink will be discharged in excess, resulting in waste in ink consumption and discharge processing time.

The present disclosure aims to provide a technique that can properly and efficiently perform preliminary ejection that is performed in response to a wiping operation on the ejection port surface of a print head.

The present disclosure relates to a recording device that records an image by ejecting ink from an ejection port provided on an ejection port surface of a print head, the ink being ejected from the ejection port in order to recover the ejection performance of the ejection port. an ejection means for performing preliminary ejection, a flow means for causing ink to flow in a flow path communicating with the ejection port, a wiping means for performing a wiping operation on the ejection port surface, and the flow path at the time of starting the wiping operation. and a control means that controls the preliminary ejection based on the flow velocity acquired by the acquisition means.

According to the present disclosure, it is possible to properly and efficiently perform preliminary ejection that is performed in response to a wiping operation on the ejection port surface of the print head.

1 is an external perspective view and a side view showing a schematic configuration of a recording device in an embodiment. FIG. FIG. 2 is a block diagram showing the configuration of a control system of the recording apparatus. FIG. 2 is a perspective view schematically showing the configuration of a recording head. FIG. 3 is a plan view of the head chip viewed from the ejection port side. FIG. 2 is a perspective view schematically showing the configuration of a recovery unit. It is a cross-sectional schematic diagram which shows a wiping mechanism. FIG. 3 is a diagram schematically showing a flow path configuration of a recording head main body and a buffer tank. FIG. 3 is a cross-sectional perspective view showing the configuration of a head chip. FIG. 2 is a plan view showing an ejection port in a head chip and its peripheral configuration. FIG. 3 is a diagram showing changes in the circulation flow rate of ink. FIG. 3 is a diagram showing the relationship between the time change of the circulating flow velocity and the operation of the recording device. 5 is a flowchart showing purge operation control in the first embodiment. It is a flowchart showing the operation in a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments do not limit the scope of the claimed invention, and not all combinations of features described in the embodiments are essential to the solution of the invention. In the embodiments described below, a printer will be used as an example of a recording apparatus using an inkjet recording method.

In this specification, "record" refers not only to the formation of significant information such as characters and figures, but also to information that is manifested in a way that humans can visually perceive, regardless of whether it is significant or not. It doesn't matter. In other words, "recording" also refers to forming an image, pattern, pattern, etc. on a recording medium, or processing the medium.

In addition, "recording medium" refers not only to paper used in general recording devices, but also to a wide range of materials that can accept ink, such as cloth, plastic films, metal plates, glass, ceramics, wood, and leather. shall be taken as a thing.

Furthermore, "ink" (sometimes referred to as "liquid") should be broadly interpreted as in the definition of "recording" above. In other words, "ink" is applied to a recording medium to form images, patterns, patterns, etc., process the recording medium, or process the ink (for example, coagulate the colorant in the ink applied to the recording medium). or insolubilization).

(First embodiment)
<Overall configuration>
FIG. 1 shows an inkjet recording device (hereinafter also simply referred to as a recording device) as a liquid ejection device according to this embodiment. 1(a) is an external perspective view of the recording apparatus 100, and FIG. 1(b) is a side view of the recording apparatus 100. The recording apparatus 100 shown in FIG. 1 records an image by scanning the recording head 110 in the x direction (main scanning direction: second direction) that intersects the y direction (transportation direction: first direction) of the recording medium 103. This is a so-called serial type recording device. Note that in this example, the x direction and the y direction are orthogonal to each other.

The recording apparatus 100 is supplied from a supply spool 131 (see FIG. 1(b)) wound with a long belt-shaped recording medium 103. That is, the recording medium 103 fed out from the supply spool 131 is held between a conveyance roller 40 and a pinch roller 41, and is sent to a recording position on the platen 104 (scanning area of the recording head) by the rotation of both rollers 40 and 41. Note that the conveyance roller 40 is interlocked with the conveyance motor 204 via a transmission mechanism such as a belt or gear, and is rotated by the driving force of the conveyance motor 204 to convey the recording medium 103 in the y direction.

The recording apparatus 100 also performs reciprocating movement (reciprocating scanning) along a guide shaft 108 extending in the main scanning direction (x direction) orthogonal to the conveyance direction (y direction) by the driving force of a carriage motor 205. A carriage 102 is provided. The carriage 102 is mounted with a recording head (liquid ejection head) 110, which will be described later, in which a plurality of ejection ports for ejecting liquid are arranged. Therefore, the recording head 110 performs reciprocating scanning along the main scanning direction together with the carriage 102. In this embodiment, a carriage belt is used as the power transmission mechanism that transmits the driving force from the carriage motor 205 to the carriage 102, but the present invention is not limited to this. It is also possible to rotate the lead screw extending in the x direction by the carriage motor 205 and move the carriage 102 engaged with the lead screw in the x direction.

The recording head 110 ejects ink (liquid) from the ejection ports at a timing based on a position signal obtained from the linear encoder 107 while performing main scanning. The print head in this embodiment uses an electrothermal conversion element (heater) 423 (see FIGS. 6 and 7) as an energy generating element (hereinafter also referred to as an ejection element) that generates ejection energy to eject ink from an ejection port. ing. The ejection element 423 is arranged at a position facing the ejection port 424 (see FIGS. 6 and 7). The ejection element 423 is driven according to recording data indicating whether ink is ejected or not ejected from the ejection port 424, foams the ink using heat generated during driving, and ejects liquid from the ejection port due to a pressure change during the bubbling. Note that as the ejection element 423, it is also possible to use an electromechanical transducer such as a piezo in addition to an electrothermal transducer (heater).

One main scan of the recording head 110 records an image on the recording medium 103 with a constant width (hereinafter referred to as band width) corresponding to the array range of the plurality of ejection ports 424. When an image of one band width is formed, the recording medium 103 is transported a predetermined distance in the y direction by the transport motor 204. Thereafter, the print head 110 performs main scanning again together with the carriage 102 to print on the print medium. In this way, a predetermined image is formed on the recording medium 103 by repeating the main scanning by the recording head 110 and the conveyance operation of the recording medium 103.

Note that in a standby state before the start of the printing operation or in a paused state of the printing operation, the carriage 102 is located at a home position set at one end of the main scanning area. At this time, the recording head 110 faces a recovery unit (recovery means) 500 provided outside the recording area where recording is performed on the recording medium 103, and the ejection opening is opened by a cap provided on the recovery unit 500, which will be described later. The surface is covered (capped).

When starting a printing operation, the cap 511 is separated from the ejection port surface of the printing head 110 to enable the printing head 110 to scan. After that, when print data for one scan is accumulated in the buffer, the carriage motor 205 causes the carriage 102 to main scan, and the print head 110 is driven according to the print data to eject ink and print onto the print medium 103. conduct. The recording medium 103 on which the image has been recorded is wound up by the take-up spool 132 to form a roll-shaped winding medium.

Further, the ink supplied to the recording head 110 is supplied to the recording head 110 from an ink tank (not shown) provided inside or outside the main body of the recording apparatus 100 via a supply tube 105 (see FIG. 5). Ru. Ink can be supplied from the ink tank to the recording head 110 by pressurizing the ink in the ink tank using a pressure unit. In addition, by capping the ejection port surface of the print head 110 with the cap 511 of the recovery unit 500 and generating negative pressure in the cap 511 with a suction pump communicating with the cap 511, the ink in the ink tank is removed into the print head 110. It is also possible to supply (fill) the

Further, the recording head 110 has a single ejection port row or a ejection port array formed by arranging a plurality of ejection ports 424 (see FIG. 7) along the conveying direction (y direction) for each type (color) of ink to be used. It has multiple head chips. The recording head 110 in this embodiment includes two head chips 402a and 402b (see FIG. 3), which will be described later.

Further, the ink supplied to the recording head 110 is supplied to the recording head 110 from an ink tank (not shown) provided inside or outside the main body of the recording apparatus 100 via a supply tube 105 (see FIG. 5). Ru. Ink can be supplied from the ink tank to the recording head 110 by pressurizing the ink in the ink tank using a pressure unit. In addition, by capping the ejection port surface of the print head 110 with a cap of the recovery unit 500 and generating negative pressure within the cap by a suction pump communicating with the cap, ink in the ink tank is supplied into the print head 110 ( Filling) is also possible.

FIG. 2 is a block diagram showing the configuration of a control system in the recording apparatus 100 shown in FIG. The recording device 100 is connected to a data supply device such as a host computer (hereinafter referred to as host PC) 306 via an interface 307 . Image data and control signals related to recording transmitted from the host PC 306 are input to the recording control unit 301 of the recording apparatus 100. The recording control unit 301 includes a memory 303 that stores input image data and programs for executing control described below. The recording control section 301 includes a CPU 302 (control means) that performs various calculation processes and controls each section of the recording apparatus 100 according to a program stored in a memory 303. Furthermore, the recording control unit includes an image processing unit 304 that performs image processing of image data together with the CPU 302, a data processing unit 305, and the like.

The CPU 302 functions as a control means that controls the transport motor 204, carriage motor 205, recovery motor 206, lifting motor 207, etc. via motor drivers 308 to 311. Further, the CPU 302 functions as first and twenty-first determination means for performing determination processing in the processing described later, and time acquisition means for acquiring elapsed time. The conveyance motor 204 is a motor that rotationally drives the conveyance roller 40 for conveying the recording medium 103, and together with the conveyance roller 40 constitutes a conveyance means. The carriage motor 205 is a motor for reciprocating the carriage 102 on which the recording head 110 is mounted. Recovery motor 206 is a motor mounted on recovery unit 500. This recovery motor 206 is a drive source for operating a suction pump 513 and wiper holder 520, which will be described later. That is, the driving force of the recovery motor 206 is selectively transmitted to the suction pump 513 and the wiper holder 520 by a camshaft (not shown). The elevating motor 207 is a motor for driving an elevating mechanism for elevating and lowering the cap, which will be described later.

Motor drivers 308, 309, 310, and 311 are drivers that rotationally drive the transport motor 204, carriage motor 205, recovery motor 206, and lifting motor, respectively. The head driver 312 is a driver that drives head chips 402a and 402b (see FIG. 3) provided in the recording head 110.

The counter group 313 is composed of a plurality of counters that count signals output from the recording control section 301. For example, the counter group 313 includes a recovery processing counter that counts the amount of ink discharged when ink is forcibly discharged from the print head 110, and a recovery processing counter that counts the amount of ink discharged from the print head 110, and a recovery processing counter that is performed before printing starts, at the end of printing, and during printing operation. It includes a preliminary discharge counter that counts the number of preliminary discharges. Furthermore, the counter group 313 also includes a borderless ink counter that counts ink printed outside the print medium area when performing borderless printing.

Further, a sensor group 314 is connected to the recording control unit 301. The sensor group 314 includes various sensors such as a temperature sensor (temperature acquisition means) that acquires the temperature of the recording head 110, an encoder sensor fixed to the carriage, and a temperature/humidity sensor that detects the temperature and humidity of the usage environment of the recording apparatus 100. Contains sensors.

The CPU 302 of the recording control unit 301 controls the driving of various motors via the above-mentioned motor drivers in accordance with control signals input via the interface 307. Further, the CPU 302 and the image processing unit 304 perform image processing on input image data, and generate print data representing whether ink is ejected or not ejected by the print head 110. The CPU 302 controls the driving of the print head 110 via the head driver 312 in accordance with the generated print data, and controls the ejection of ink by the print head 110.

<Recording head>
FIG. 3 is a perspective view showing the configuration of the recording head 110 in this embodiment. The recording head 110 includes a recording head main body 120 and a buffer tank (liquid holding section) 401 that supplies ink to the recording head main body 120. In this embodiment, a plurality of buffer tanks are provided as the buffer tank 401 corresponding to a plurality of colors of ink. In this example, eight colors of ink are used: black (Bk), gray (Gy), light gray (Lgy), light cyan (Lc), cyan (C), light magenta (Lm), magenta (M), and yellow (Y). Eight independent buffer tanks are provided, one for each buffer tank. That is, buffer tanks 401Bk, 401Gy, 401Lgy, 401LC, 401C, 401Lm, 401M, and 401Y are provided. In the following explanation, when referring to the eight buffer tanks individually, the reference numerals attached to each one are used, and when referring to the eight buffer tanks comprehensively, a generic reference numeral is used. 401 is used.

The eight buffer tanks 401 are communicatively connected to flow paths corresponding to each ink color of the recording head main body 120. Although the buffer tank 401 is shown in a visible state in FIG. 3 for the sake of explanation, the buffer tank 401 is actually housed in a covered state in the housing of the recording head 110. Two head chips 402a and 402b made of semiconductor or the like are attached to the lower surface of the recording head main body 120. Each of these head chips 402a and 402b is formed with a group of ejection ports corresponding to four types of ink.

In each of the head chips 402a and 402b, a group of 1024 ejection ports arranged in two rows and one set at an interval of 1200 dpi per color is arranged in the main scanning direction (x direction). That is, each head chip 402a, 402b has an ejection port group consisting of eight ejection port arrays, and each of the head chips 402a, 402b is capable of ejecting four colors of ink. ing. Therefore, the print head 110 can print a full-color image using eight color inks ejected from the two head chips 402a and 402b.

Note that in this embodiment, an example is shown in which eight ejection port arrays are arranged in each of the head chips 402a and 402b, but the present invention is not limited to this. The number of head chips, the number of ejection port groups provided in each head chip, the number of ejection port rows that make up each ejection port group, and the number and density of ejection ports that make up each ejection port row are determined as necessary. The design can be changed as appropriate. For example, it is also possible to arrange ejection port groups for two colors in one head chip. Further, a head chip may be provided for each ink color. Furthermore, it is also possible to configure the ejection port group for one color by one ejection port row consisting of a plurality of ejection ports arranged in the same straight line. Furthermore, it is also possible to configure the ejection port group for one color by three or more ejection port arrays that are parallel to each other. For example, by arranging 512 ejection ports that eject ink of the same color on the same straight line at intervals of 600 dpi, and arranging 4 rows of ejection ports parallel to each other, the ejection ports for one color can be May form a group. In this case, by shifting the positions of the ejection ports constituting each ejection port row in the y direction by 2400 dpi, it becomes possible to form an image with a resolution of 2400 dpi using one ejection port group.

FIG. 4 is a plan view of one of the two head chips 402a and 402b provided in the recording head 110, viewed from the ejection port side. In order to simplify the illustration, the size ratio of each part is shown in FIG. 6 as being different from the actual size, but the actual size of the head chip 10b is 9.55 mm in the x direction and 39.0 mm in the y direction. It has become.

Each of the ejection port rows 115 to 118 of the head chip 402b is a set of two ejection port rows, each of which is a combination of a first ejection port row L1 and a second ejection port row L2 that are adjacent to each other. Each of the first and second ejection port rows includes 768 ejection ports arranged at a pitch of 1200 dpi (dots/inch) in the y direction. Moreover, the arrangement positions of the ejection ports of the ejection ports 424 of the first ejection port row L1 and the second ejection port row L2 are shifted by 1/2 pitch from each other in the y direction. Therefore, each of the ejection port arrays 111 to 118 has a configuration in which substantially 1536 ejection ports 424 are arranged in the y direction at a density of 2400 dpi. Note that in this embodiment, 1200 dpi corresponds to approximately 0.02 mm.

Here, the head chip 110b has nine diode sensors (temperature detection means) S111 to S111 disposed at multiple locations (nine locations) on the head chip 110b as temperature acquisition means for acquiring the temperature of ink near the recording element. S119 is formed. Of the nine diode sensors, two diode sensors S111 and S116 are arranged near one end in the y direction of the discharge port arrays 115 to 118. Specifically, the diode sensors S111 and S116 are each arranged at a position 0.2 mm away from the discharge port at one end in the y direction. Here, the diode sensor S111 is arranged between the ejection port rows 115 and 116 in the x direction, and the diode sensor S116 is arranged between the ejection port rows 117 and 118 in the x direction.

Further, two diode sensors S112 and S117 are arranged near the other end of the discharge port arrays 115 to 118 in the y direction. Here, the diode sensor S112 is arranged between the ejection port rows 115 and 116 in the x direction, and the diode sensor S117 is arranged between the ejection port rows 117 and 118 in the x direction. Specifically, the diode sensors S112 and S117 are each arranged at a position 0.2 mm away from the discharge port at the other end in the y direction.

Further, five diode sensors S113, S114, S115, S118, and S119 are each arranged at the center of the discharge port arrays 115 to 118 in the y direction. Here, the diode sensor S114 is arranged between the ejection port array 115 and the ejection port array 116 in the x direction. The diode sensor S115 is arranged between the discharge port rows 116 and 117 in the x direction. The diode sensor S118 is arranged between the discharge port rows 117 and 118 in the x direction. Further, the diode sensor S113 is arranged outside the ejection port row 115 in the x direction, and the diode sensor S119 is arranged outside the ejection port row 118 in the x direction.

Note that in this embodiment, the temperature of the ink in the ejection port near the diode sensor is almost the same as the temperature of the head chip 110b at the position where the diode sensor is provided, so the temperature of the head chip 110b is determined by the temperature of the ink. Treated as the temperature.

Further, the head chip 110b is provided with heating elements (hereinafter also referred to as sub-heaters) 119a and 119b for heating the temperature of ink within the ejection port. Here, the heating element 119a is formed of a continuous member so as to surround the side of the ejection port array 115 in the x direction where the diode sensor S113 is provided. Similarly, the sub-heater 119b is formed of a continuous member so as to cover the side of the discharge port array 118 in the x direction where the diode sensor S119 is provided. Note that the sub-heaters 119a and 119b are located 1.2 mm outside the discharge port row 113 in the x direction and 0.0 mm away from the diode sensors S111, S112, S116, and S117 in the y direction. Located 2mm outside.

Although the head chip 402b has been described in detail here, the head chip 402a also has a substantially similar configuration.

In this embodiment, a representative temperature is calculated based on the temperatures detected by each of the diode sensors S111 to S119, and various temperature controls are performed using the representative temperature as the ink temperature. Here, in order to simplify the explanation, the temperature detected by the diode sensor S115 will be described as a representative temperature in various temperature controls. Note that this representative temperature setting process is performed by the CPU 302.

However, this embodiment is not limited to such a configuration in which the detected temperature from a single diode sensor is always used in common for all temperature controls. For example, the combination of temperature sensors used to calculate the representative temperature may be changed for each type of temperature control. For example, the representative temperature may be the average value of the temperatures detected by four surrounding diode sensors S111, S112, S113, and S114.

<Recovery unit>
FIG. 5 is a perspective view schematically showing the configuration of a recovery unit (recovery means) 500 according to this embodiment. The recovery unit 500 has two caps 511 facing each of the two head chips 402 (402a, 402b (FIG. 3)) of the print head 110 when the print head 110 is at the home position at the end of the main scanning area. (511a, 511b). The caps 511a and 511b are supported so as to be able to rise and fall by a lifting mechanism (not shown), and move between a raised position (closed position) and a lowered position (opened position). When the caps 511a and 511b are in the raised position, the head chips 402 (402a, 402b) are in close contact with the lower surface of the print head 110, and cover (cap) the ejection port surface F (Fa, Fb (FIG. 3)) of the print head. . By capping the ejection port surfaces Fa and Fb, it is possible to prevent damage to the ejection port surfaces Fa and Fb, and to suppress evaporation of volatile components of ink from the ejection ports 424 of each head chip 402a and 402b. It becomes possible to suppress thickening and sticking of ink.

Suction ports 511a1, 511b1 are formed at the bottoms of the caps 511a, 511b, and tubes 512a, 512b communicating with suction pumps 513a, 513b are connected to the suction ports 511a1, 511b1. Further, the caps 511a and 511b are connected to an on-off valve (not shown) via a tube. The on-off valve is also referred to as an atmospheric valve, and by closing the atmospheric valve and performing capping, the spaces inside the caps 511a and 511b are cut off from communicating with the space outside the caps (atmosphere). In this manner, when capping is performed and the atmospheric valve is closed, ink can be sucked from the ejection ports by driving suction pumps 513a and 513b, which will be described later. On the other hand, when the atmospheric valve is opened and the suction pump is driven in the capped state, the ink in the caps 511a and 511b can be discharged without suctioning the ink from the ejection port 424. Note that during the printing operation, the caps 511a and 511b are held at a position (lowered position) separated from the head chips 402a and 402b to avoid interference with the printing head 110 that moves together with the carriage 102. With the cap 511 in the lowered position, the recording head 110 can perform a purge operation (wiping operation) on the cap 511 when moved to a position facing the cap 511.

The suction pumps 513a and 513b in this embodiment are configured by tube pumps. The tube pumps 513a, 513b rotatably support a holding part (not shown) having a curved surface part that holds a part of the tubes 512a, 512b connected to the caps 511a, 511b, and a pressing roller (not shown). It includes rotating bodies 514a and 514b. The rotating bodies 514a, 514b are rotated by the recovery motor 206 (FIG. 2). As the rotating bodies 514a and 514b rotate, the pressure roller moves while crushing the tubes 512a and 512b, and transfers the fluid (ink and gas) in the tubes 512a and 512b to the discharge side. As a result, negative pressure is generated inside the cap 511 in the capping state. At this time, if the atmospheric valve is closed, ink is sucked from the ejection ports 424 of each head chip 402a, 402b, and the sucked ink is discharged to a waste ink absorber (not shown) via tubes 512a, 512b. Ru. This discharge operation discharges thickened or solidified ink, ink containing dust or air bubbles, etc. present in the discharge port 424, making it possible to restore the discharge performance of the discharge port 424 to an appropriate state. Become.

The suction operation by the suction pumps 513a and 513b is also performed when ink received in the cap 511 by preliminary ejection is discharged to the waste ink absorber via the cap 512. For example, when the amount of ink received in the cap 511 due to preliminary ejection reaches a predetermined amount, the atmospheric valve is opened and the suction pumps 513a and 513b are driven to remove the ink received in the cap 511 from the cap 512. The waste ink can be discharged through the waste ink absorber. Further, the suction operation using the caps 511a, 511b and the suction pumps 513a, 513b is also performed when filling ink into the recording head 110 from the buffer tank 401 (at the time of initial filling).

Further, the recovery unit 500 is provided with a wiping mechanism (wiping means) that wipes the ejection port surfaces Fa and Fb of the head chips 402a and 402b with a wiper (wiping member) 521. Here, the wipers 521 include two wipers 521a and 521b that perform wiping (wiping operation) on the ejection orifice surfaces Fa and Fb of the two head chips 402a and 402b in FIG. 3, and two ejection orifice surfaces Fa and Fb. A single wiper 521c is provided for wiping. Wipers 521a, 521b, and 521c are fixed to wiper holder 520. The wiper holder 520 is supported so as to be movable along a guide 523 extending in the arrangement direction (x direction) of the ejection ports in the recording head 110 .

By moving the wiper holder 520 in the y1 direction when the recording head 110 is located at the standby position (home position), the wipers 521a, 521b, and 522 move while contacting the ejection port surfaces Fa and Fb. Thereby, ink, dust, etc. adhering to the ejection port surfaces Fa and Fb can be wiped away. Hereinafter, this operation will be referred to as wiping. When this wiping is completed, the carriage 102 is moved in the x2 direction to retreat from the area to be wiped. Thereafter, the wiper holder 520 is moved in the y2 direction, and the wipers 521 and 522 are returned to their original positions (the positions before wiping).

In this embodiment, the wipers 521 (521a, 521b, 521c) are made of an elastic member such as rubber, but may be made of a porous member (for example, nonwoven fabric) that absorbs ink.

Here, the internal structures and operations of the wiping mechanism in which the wiper 521 is made of an elastic member and the wiping mechanism in which the wiper 521 is made of a porous member will be described with reference to FIG. 6.

FIG. 6A is a schematic cross-sectional view showing an example of a wiping mechanism (wiping means) 530 having a wiper 521 made of a rubber elastic member. The wiping mechanism shown here corresponds to the wiping mechanism provided in the recovery unit 500 in FIG. 4. The wiping mechanism 530 shown in FIG. 6A includes a wiper holder 520 movable in the y direction and a wiper 521 held by the wiper holder 520. The wiper 521 is made of a rubber elastic member, and is elastically supported in the z direction by a spring 531 provided within the wiper holder 520. This wiper 521 is brought into contact with the ejection port surface F of the recording head 110 located at the home position, and is moved together with the wiper holder 520 in the y1 direction (wiping direction). As a result, the ejection port surface F of the recording head 110 is completely wiped. At this time, the wiper 521 performs a wiping operation without absorbing the ink adhering to the ejection port surface F. Therefore, if a large amount of ink adheres to the ejection orifice surface F, while the ink is being wiped off, ink of other colors will enter from the ejection orifice 424 and mix into the flow path, causing the ink to be mixed inside the recording head 110. There is a possibility that color mixing may occur. Therefore, after the wiper 521 performs the wiping operation, preliminary ejection (also referred to as purge) is performed to eject the mixed color ink from the ejection port 424 and the flow path.

Further, FIG. 6(b) is a schematic cross-sectional view showing an example of a wiping mechanism 550 in which a wiper (wiping member) for wiping the discharge port surface F is made of a porous member (here, a nonwoven fabric). The wiping mechanism 550 shown here includes a belt-shaped sheet member 541 constituting the wiper, a supply roller 542 that supplies the sheet member 541, a take-up roller 543 that collects the sheet member 541, a pressing member 544, and a pressing spring. 545 and the like are housed in the wiper holder 540. The sheet-like member 541 is wound around a supply roller 542, and the sheet supplied from the supply roller 542 is wound around a take-up roller 543. The sheet-like member 541 is used in a state in which it is previously impregnated with an impregnating liquid. As the impregnating liquid, a liquid consisting of water, a surfactant, a solvent, etc. is used. More specifically, an impregnation liquid containing a low volatility solvent such as polyethylene glycol as a main component is used. Further, the pressing member 544 presses the sheet-like member 541 from the supply roller 542 to the take-up roller 543 from below to above by the compression spring 544. Thereby, the contact pressure of the sheet-like member can be changed depending on the area of the discharge port surface 18 that is wiped by the sheet-like member 541.

In the wiping mechanism 550 shown in FIG. 6B, the wiper holder 540 is moved in the y1 direction while pressing the sheet-like member 541 against the ejection port surface F of the recording head 110 by the pressing member 544. Thereby, the sheet-like member 541 wipes the discharge port surface F as a wiper. When a nonwoven fabric is used as a wiper, ink penetrates into the wiper, so a wiping operation is performed while absorbing ink on the ejection port surface F. Therefore, it is possible to suppress the ink from entering the ejection port 424, and it is possible to suppress the occurrence of color mixing of ink in the ejection port and the flow path. However, after the wiping operation, the sheet-like member 541 has reduced ink absorbency and has ink adhered to its surface. For this reason, the supply roller 542 and take-up roller 543, which constitute the sheet moving means, are rotated as appropriate to move the sheet-like member 541 in the longitudinal direction, thereby performing a wiping operation while maintaining good ink absorption and wiping performance. The sheet-like member 541 may be moved each time the wiping operation is completed, or may be performed while the wiping operation is being performed, and the movement control of the sheet-like member 541 can be changed as necessary.

In this embodiment, an example has been shown in which the wipers 521 and 541 wipe the discharge port surface F only when moving in the forward direction (y1 direction), but the present invention is not limited to this. The discharge port surface F may be wiped both when the wipers 521 and 541 move in the forward direction (y1 direction) and in the backward direction (y2 direction). Further, in this embodiment, the wiping direction is the arrangement direction (y direction) of the ejection ports 424 in the recording head 110, but the wiper 521 is moved in a direction (x direction) that intersects (orthogonal to) the y direction. Good too. Furthermore, a configuration may be adopted in which the wiper 521 is fixed and the carriage 102 moves in the main scanning direction (x direction) to wipe the discharge port surface F. Further, it is also possible to use a configuration in which a plurality of wipers 521 are used to wipe in different directions. In this case, each recovery unit may be placed at a different position. For example, one recovery unit may be placed near the standby position of the carriage 102, and the other recovery unit may be placed on the opposite side of the recording area on the recording medium. Furthermore, it is also possible to use a vacuum wiper that can suction the wiped ink using negative pressure.

<Ink circulation>
FIG. 7 is a diagram schematically showing the flow path configuration of the recording head 110 and the buffer tank 401. Although the configuration of the ink flow path for one color is shown here, in this embodiment, buffer tanks 401C, 401M, 401Y, and 401BK corresponding to ink for eight colors are provided, and the print head 110 is provided with buffer tanks 401C, 401M, 401Y, and 401BK corresponding to ink for eight colors. A flow path for ejecting ink is formed.

The supply tube 105 passes through the inside of the carriage 102 and is connected to a joint 404 of the recording head 110, and the joint 404 communicates with the buffer tank 401. The ink supplied to the supply tube 105 is supplied to the buffer tank 401 via the joint 404. In the buffer tank 401, the ink supplied from the joint 404 passes through the filter 405, the flow path 450, and the valve 411, and reaches the first pressure control member 406. The first pressure control member 406 is connected to the second pressure control member 407 via a flow path 451 and a valve 412. Further, the second pressure control member 407 is connected to a circulation pump (flow means) 408 via a flow path 452, and the circulation pump 408 is connected to the first pressure control member 406 via a flow path 453.

A valve 411 connected to the inlet of the first pressure control member 406 and a valve 412 connected to the inlet of the second pressure control member 407 are each configured to open when a predetermined negative pressure is applied thereto. There is. The negative pressure at which the valve 412 of the inlet of the second pressure control member 407 opens is set to a higher negative pressure than the negative pressure at which the valve 411 of the first pressure control member opens.

Ink is supplied to the head chip 402 from the first pressure control member 406 via a channel 454 and a common supply channel 409. The ink supplied into the head chip 402 flows into a supply channel, which will be described later, that communicates with one or more ejection port arrays arranged within the head chip 402. A portion of the ink that has flowed into the supply channel is supplied to each ejection port in the ejection port array, and the remaining ink passes through a recovery channel (described later) formed within the head chip 402 and enters the recording head main body 120. Inflow. The ink that has flowed into the recording head main body 120 passes through a common recovery channel 410 formed within the recording head main body 120 and is returned to the second pressure control member 407 via a channel 455.

In this way, the recording head 110 is connected to the circulation pump 408 as an ink supply source, through the first pressure control member 406 and the common supply channel 409, to the channel communicating with the ejection port 424 in the head chip 402. A flow path on the supply side is formed. Further, a recovery-side flow path is formed from the flow path communicating with the discharge port 424 of the head chip 402 to the circulation pump 408 via the common recovery flow path 410 and the second pressure control member 407. The supply side flow path and the recovery side flow path form a circulation flow path that circulates within the recording head 110.

Here, the channel configuration and ink flow within the head chip 402 will be described with reference to FIGS. 8 and 9. FIG. 8 is a cross-sectional perspective view showing a part of the structure of the head chip 402 (402a, 402b), and FIG. 9 is a plan view showing the ejection port 424 formed in the head chip 402 and its peripheral structure. As shown in FIG. 8, the head chip 402 mainly includes an orifice plate 420, a substrate 430, and a cover plate 440, and has a structure in which these are sequentially stacked from the front side. A discharge port 424 is formed in the orifice plate 420 located at the outermost surface side of the head chip 402 . On the surface of the substrate 430 overlapping the orifice plate 420 (the surface facing the orifice plate 420), an ejection element 423 that generates ejection energy for ejecting ink is provided at a position facing the ejection opening 424. As described above, in this embodiment, an electrothermal conversion element (heater) is used as the ejection element 423.

A pressure chamber 433 is formed between the substrate 430 and the orifice plate 420. Furthermore, a supply channel 431 and a recovery channel 432 are formed in the substrate 430, which extend along the arrangement direction (y direction) of the discharge ports 424. The supply channel 431 communicates with the pressure chamber 433 via an inlet 421 formed in the top plate portion 434 of the substrate 430 . Furthermore, the recovery channel 432 communicates with the pressure chamber 433 via an outlet 422 formed in the top plate portion 434 . The inlet 421 and the outlet 422 are located on both sides of the outlet 424, as shown in the plan view of FIG. In this embodiment, as shown in FIG. 9, one inlet port 421 and one outlet port 422 are arranged for each of the two discharge ports 424. Note that the number of inflow ports and outflow ports may be one for each discharge port 424, or conversely, one for each of three or more discharge ports 424.

The supply channel 431 and the recovery channel 432 are covered with a cover plate 440. The cover plate 440 is formed with a supply opening 441 and a recovery opening (not shown). The supply opening 441 communicates with the supply channel 431, and the recovery opening A recovery flow path 432 is communicated with. One or more supply openings 441 are formed for each supply channel 431. Similarly, one or more recovery openings are provided for the recovery channel 432. However, the number of supply openings and the number of recovery openings may be the same or different. As described above, in the head chip, the flow path communicating with the discharge port 424 is configured by the pressure chamber 433, the supply flow path 431, and the recovery flow path 432.

Next, with reference to FIG. 7, a method of supplying ink to the print head 110 and buffer tank 401 and a method of circulating ink within the print head 110 in this embodiment will be described. The ink is pressurized from an ink tank (not shown), reaches the recording head 110 via the supply tube 105, passes through the filter 405, and then flows into the flow path 450. As described above, when the ejection port 424 is filled with ink at an appropriate negative pressure so that the meniscus is maintained, the valve 411 connected to the inlet of the first pressure control member 406 is closed. It becomes. Therefore, ink does not flow into the first pressure control member 406. However, if a strong negative pressure is applied to the ejection port 424 due to the suction operation by the cap 511 of the recovery unit 500, or if ink is ejected from the ejection port 424, the negative pressure of the first pressure control member 406 becomes higher, so valve 411 opens. As a result, ink flows into the first pressure control member 406.

As shown in FIG. 7, the first pressure control member 406 and the second pressure control member 407 are connected to a circulation pump 408, and when the circulation pump 408 is driven, the first pressure control member 407 is transferred to the second pressure control member 407 via the circulation pump 408. Ink flows to pressure control member 406 . Then, the negative pressure in the second pressure control member 407 increases, and the valve 412 communicating with the inlet of the second pressure control member 407 opens. As a result, ink flows back from the first pressure control member 406 to the second pressure control member 407. At this time, a pressure difference occurs between the first pressure control member 406 and the second pressure control member 407. Due to this pressure difference, ink flows in the order of first pressure control member 406 → common supply channel 409 → supply opening 441 → supply channel 431 → inlet 421 → pressure chamber 433, and some of the ink flows It flows into the discharge port 424. Further, the remaining ink that has not been supplied to the ejection port 424 flows in the order of the pressure chamber 433 → the outlet 422 → the recovery channel 432 → the opening 441 → the common recovery channel 410, and returns to the second pressure control member 407.

Note that the negative pressure in the discharge port 424 and the flow rate of the ink are adjusted so that the flow rate of the pump and the pressure of the flow path between the first pressure control member 406 and the second pressure control member 407 are within a range that can maintain the meniscus. It is adjusted by the loss and the opening/closing force of the valves 411 and 412.

As described above, by driving the circulation pump 408, the ink near the discharge port 424 flows. Thereby, it is possible to suppress drying of the ink in the ejection ports 424 or increase in ink viscosity during the recording operation, and it is possible to suppress deterioration in the ink ejection performance of each ejection port 424.

<Purge discharge after wiping operation>
Here, purge discharge performed after the wiping operation will be explained. In the inkjet recording apparatus 100, there is a risk that ink mist and the like generated during ink discharge may adhere to the discharge port surface F of the recording head 110, reducing the discharge performance of the recording head. Therefore, it is necessary to remove the ink adhering to the ejection port surface F, and a wiping operation for wiping the ejection port surface F is performed by the wiper 521. However, in the wiping operation, the ink adhering to the ejection port surface F is spread out and pushed into the ejection port 424, which may reduce the ejection performance and image quality. In particular, if the ink pushed into the ejection port 424 is of a different color from the ink that should be ejected from the ejection port 424, color mixture occurs within the recording head 110. Therefore, normally, after the wiping operation, ink that does not contribute to the recording operation is ejected from each ejection port 424, that is, purge ejection is performed, and inappropriate ink that has entered from the ejection port 424 is ejected by wiping.

If the recording device has a configuration that does not perform ink circulation, the ink that enters through the ejection port 424 remains near the ejection port 424, so a small amount of ink is ejected by the purge operation to prevent inappropriate ink such as mixed color ink from being ejected. can be completed. However, in this embodiment, a configuration is adopted in which the ink is circulated within the recording head 110 in order to suppress thickening, solidification, etc. of the ink and maintain good ejection performance. For this reason, in the recording apparatus 100 of the present embodiment, the ink that has entered the ejection port 424 is immediately spread to the depths of the flow path by the ink flow in the flow path communicating with the ejection port 424. You will be washed away. Therefore, in order to discharge inappropriate ink by the purge operation, it is necessary to perform a large number of ejections in the purge operation.

FIG. 10 is a diagram showing changes in the circulation flow velocity of ink from a state during a printing operation to when wiping is performed after the printing operation is completed. As described above, during the printing operation, ink is circulated by the circulation pump 408 in order to stabilize the ejection performance of the printing head 110, and when the printing operation is completed, the circulation pump 408 is stopped. When the driving of the circulation pump 408 is stopped, as shown in FIG. 10, the ink flow rate decreases over time, and finally the ink flow stops.

FIG. 10 shows a case where a constant pressure difference occurs between the first pressure control member 406 and the second pressure control member 407 during the recording operation, and the ink flow rate is also constant. Note that when ink is ejected during a recording operation, the negative pressure between the first pressure control member 406 and the second pressure control member 407 increases temporarily, and the pressure difference between them also changes. However, as the negative pressure increases, the valve 411 communicating with the inlet of the first pressure control member 406 opens, and ink is supplied from the ink tank to the buffer tank 401, so that the original pressure state is restored.

When the recording operation is completed and the circulation pump 408 serving as the circulation means is stopped, the recording head 110 returns to its home position. After the recovery unit 500 performs a necessary recovery operation on the recording head 110 located at the home position, the cap 511 caps the ejection port surface F of the recording head 110. FIG. 10 shows an example in which the preliminary operation is the initialization operation in which the recording head 110 returns to the home position and the wiper 521 of the recovery unit 500 is moved to the wiping start position, and wiping is performed after the preliminary operation.

After the recording operation is completed, there is no need to circulate the ink in the recording head 110 to suppress the increase in viscosity due to evaporation, so the drive of the circulation pump 408 is stopped at the timing of stopping the circulation drive shown in FIG. However, immediately after the circulation pump 408 stops, a pressure difference remains between the first pressure control member 406 and the second pressure control member 407, and the valve 412 at the inlet of the second pressure control member 407 is in an open state. . Therefore, the flow path 421 between the first pressure control member 406 and the second pressure control member 407 and the flow path communicating with the ejection port 424 formed in the recording head main body 120 continue for a certain period of time. The ink continues to flow. The pressure difference between the first pressure control member 406 and the second pressure control member 407 gradually decreases as the ink flows, so the valve 412 becomes closed. After that, the ink continues to flow through the flow path communicating with the ejection port 424, but the circulating flow velocity of the ink gradually decreases, and after a certain period of time, the circulating flow of ink almost stops.

If the time from the stop of the circulation drive to the start of wiping is longer than the time from the stop of the circulation drive to the stop of the circulating flow, wiping will be started with the circulation flow stopped. In this case, even if mixed color ink or foreign matter enters the ejection port 424 due to wiping, the problem of them entering deep into the flow path does not occur.

On the other hand, as shown in FIG. 10, if the time from the stop of the circulation drive to the start of wiping is shorter than the time from the stop of the circulation drive to the stop of the circulation flow velocity, the circulation flow has not stopped. Therefore, in order to prevent mixed color ink and foreign matter from penetrating deep into the flow path, it is necessary to wait until the circulating flow stops before starting wiping. FIG. 11A shows the relationship between the time change in the circulating flow velocity and the operation of the recording apparatus 100 in this case. As shown in FIG. 11(a), when wiping is performed after waiting for the circulation flow to stop, a wait time occurs after the preliminary operation, which delays the start of the next recording operation, reducing the productivity of the recording apparatus 100. will decrease.

In addition, as shown in FIG. 11(a), as a method to avoid a decrease in productivity due to delaying the wiping start timing, by stopping the driving of the circulation pump 408 during the recording operation, the circulating flow is It is possible to stop the FIG. 11(b) shows the relationship between the change in circulating flow velocity over time and the operation of the recording apparatus 100 when this method is implemented. In the method shown in FIG. 11(b), since the driving of the circulation pump 408 is stopped during the recording operation, the circulation flow velocity decreases until the recording operation is finished, and the circulation flow velocity is almost stopped at the end of the preliminary operation. becomes possible. According to this, it becomes possible to start wiping without providing a wait time after the completion of the preliminary operation, so it is possible to suppress a decrease in productivity. However, in this case, a period (the period indicated by the shaded area in FIG. 11B) in which the circulating flow velocity is slower than the circulating flow velocity V1 required to maintain the ejection performance of the recording head 110 occurs during the recording operation. For this reason, in the period of the shaded area, viscosity increases due to ink evaporation, resulting in a decrease in ejection performance, disturbance in the landing position of ink, etc., and there is a concern that image quality will deteriorate.

Therefore, in order to avoid a decrease in productivity, as shown in FIG. 10, it is necessary to perform the wiping operation while the circulating flow velocity remains, and to eliminate color mixing by the purging operation. In this case, the time and ink ejection amount required for recovery of ejection performance by the purge operation vary greatly depending on the amount of mixed ink, the circulation flow rate, the time from the start of wiping to the purge operation, and the like. In this embodiment, an example will be described in which the time from wiping to purge operation is short and high productivity can be obtained.

Here, the circulating flow velocity of ink within the recording head 110 will be explained. The circulation flow rate within the recording head 110 is expressed as the flow rate of ink per unit time. The higher this circulation flow velocity is at the end of the recording operation, that is, when the circulation drive is stopped, the greater the pressure difference between the first pressure control member 406 and the second pressure control member 407 (hereinafter simply referred to as pressure difference) after the circulation drive is stopped. resolved sooner. Therefore, the faster the circulation flow rate when the circulation drive is stopped, the smaller the pressure difference at the start of wiping becomes, and the slower the circulation flow rate becomes, so the amount of mixed color ink that enters the inner part of the flow path also decreases. Therefore, when a printing operation is performed under conditions in which it is difficult to eliminate the pressure difference after the printing operation is finished, color mixing can be efficiently eliminated by increasing the number of ejections in the purge operation after wiping.

As described above, the higher the circulation flow velocity when the circulation drive is stopped in response to the end of the recording operation, the faster the pressure difference after the circulation drive is stopped is eliminated. If the driving conditions of the circulation pump 408 are the same, the lower the viscosity of the ink, the higher the circulation flow velocity, and the higher the temperature of the ink, the lower the viscosity of the ink. In other words, the higher the temperature of the recording head 110, the higher the temperature of the circulating ink, and the faster the pressure difference after the circulation drive is stopped is eliminated. Therefore, the higher the temperature of the recording head 110, the lower the circulating flow velocity at the start of wiping, and the less the amount of mixed color ink entering the inner part of the flow path.

Therefore, in this embodiment, the temperature of the ink is detected by a temperature sensor mounted on the recording head 110, and when the detected temperature is high, the number of ejections by the purge operation is relatively reduced, and when the detected temperature is low, the ink temperature is detected. Control is performed to relatively increase the number of discharges due to purge operation. This makes it possible to perform an appropriate purge operation with no excess or deficiency. That is, by wiping, inappropriate ink such as mixed color ink existing in the ejection port and the flow path can be reliably discharged, and it is also possible to suppress discharge of excessive ink.

<Purge operation control using this embodiment>
The purge operation control executed in this embodiment will be explained based on the flowchart of FIG. 12. It is assumed that each process in the flowchart of FIG. 12 is executed by the CPU 302. Further, the S attached to each step number in the flowchart of FIG. 12 and the flowchart shown in FIG. 13, which will be described later, means a step.

The CPU 302 performs processing as an acquisition unit that acquires the circulation flow velocity of ink at the time of starting wiping (S1201). The circulation flow velocity of this ink is determined by the wiping start time (first elapsed time) from the time when the circulation drive is stopped until the wiping start, and the circulation flow velocity remaining time (the second elapsed time) which is the time from the time when the circulation drive is stopped until the ink flow stops. (elapsed time). Note that the circulation flow rate remaining time is derived based on the ink temperature detected by the temperature sensor. That is, the circulation flow rate remaining time becomes shorter when the detected ink temperature is high, and becomes longer when the detected ink temperature is low. If the wiping start time from the ink circulation drive stop time to the wiping start is longer than the circulation flow velocity remaining time determined by the ink temperature, the ink flow velocity at the time of wiping start becomes zero. Furthermore, if the circulating flow velocity remaining time is longer than the wiping start time, the ink will be in a flowing state at the time of wiping start.

Next, in S1202, the CPU 302 determines the purge operation to be performed based on the obtained circulation flow rate (S1202). That is, if the obtained circulating flow velocity of ink at the start of wiping is 0, a purge operation with a standard number of ejections is determined. Furthermore, if the obtained circulation flow rate is not 0, a purge operation with a discharge amount corresponding to the circulation flow rate is determined (S1203). That is, if the ink circulation flow velocity at the start of wiping is relatively high, a purge operation is determined that has a relatively large degree of recovery of ejection performance, and if the circulation flow velocity is relatively small, the ejection performance is restored. determine a purge operation that has a relatively small degree of Note that the degree to which the ejection performance is restored is determined by the number of ejections, ejection speed (ejection frequency), etc. in the purge ejection operation.

Thereafter, the CPU 302 starts wiping (S1204), and after a predetermined wiping is performed, ends the wiping (S1205). When wiping is completed, the CPU 302 executes the purge operation determined in S1202.

Note that in this embodiment, in S1201 of FIG. 12, the circulating flow velocity at the start of wiping was calculated using the wiping start time and the circulating flow velocity remaining time, but the method for obtaining the circulating flow velocity at the start of wiping is not limited to this. . For example, it is also possible to use a direct flowmeter to measure the circulation flow rate at the start of wiping, or to measure the pressure difference between each liquid chamber with a pressure gauge and obtain the circulation flow rate at the start of wiping based on the measured pressure. It is.

As described above, in this embodiment, the degree of intrusion of mixed color ink, etc. into the flow path is predicted from the circulation flow velocity, and the purge operation is performed with the number of ejections according to the prediction, thereby reducing the amount of waste ink due to excessive purge operation. This suppresses the increase in purge time and maintains appropriate discharge performance. On the other hand, in the conventional purge operation after wiping, the purge operation is performed assuming the severest degree of color mixing that can occur due to wiping. The effectiveness of this embodiment will be specifically explained below in comparison with a comparative example in which a conventional purge operation is performed.

First, the wiping operation and the occurrence of color mixture after wiping will be explained. Note that the wiping operation is performed under the same conditions in both the present embodiment and the comparative example.

First, the time from the stop of ink circulation in the recording head 110 (stopping of circulation pump 408) until the wiper comes into contact with the ejection port surface for wiping (hereinafter referred to as wiper contact time) was measured. As a result, the wiper contact time was 10 to 15 seconds. In this example, a wiper made of elastic resin is used, and wiping is started when the wiper contact time has elapsed.

Further, under a temperature condition where the ink temperature was 25° C., the time from the stop of the circulation drive until the ink flow actually stopped (circulation flow rate remaining time) was measured. As a result, it was confirmed that the circulation stop time was about 20 seconds.

As a result of performing wiping under the above conditions, color mixture occurred in the flow path of the recording head 110. This is because, as described above, the wiper contact time is shorter than the circulation stop time, and the ink is flowing when wiping starts.

After the above wiping operation, a purge operation was performed under the following conditions, and the degree of color mixture occurring in the recording head 110 was confirmed. First, the ejection frequency in the purge operation was set to 10 kHz, and the number of ejections was set to 100,000 times. Hereinafter, the conditions for this purge operation will be referred to as purge operation conditions [1]. As a result of performing the purge operation under the purge operation condition [1], no color mixture was observed in the ink ejected from the print head 110, and it was confirmed that the color mixture that had occurred inside the print head 110 was resolved.

In addition, when the purge operation was performed under the purge operation conditions (hereinafter referred to as purge operation condition [2]) in which the ejection frequency was 1 kHz and the number of ejections was 1000 shots, it was confirmed that color mixing was not resolved. This is because under the purge operation condition [2], the discharge speed and amount of ink due to the purge operation are reduced compared to the purge operation condition [1]. However, when the wiping contact time was 30 seconds, it was possible to eliminate color mixing even under purge operation condition [2]. This is because by delaying the wiping start timing, the ink flow velocity at the time of wiping start is lowered, and the degree of color mixing is reduced. As described above, it has become clear that when the degree of color mixing caused by the wiping operation is small, the color mixing can be eliminated even if the ejection frequency and the number of ejections are reduced as the purge operation conditions.

When the above purge operation conditions and color mixture elimination state are taken into consideration, in the comparative example, the purge operation under purge operation condition [1] is always performed assuming a situation where maximum color mixture occurs. In contrast, in this embodiment, in S1202 of FIG. 12, the degree of color mixing is predicted from the circulating flow velocity at the start of wiping, and the purge operation conditions for the number of ejections are determined in accordance with the prediction. In other words, if the circulating flow velocity at the start of wiping is high and the degree of color mixing is significant, purge operation condition [1] is implemented, and if the circulating flow velocity at the start of wiping is low and the degree of color mixing is slight, , implement purge operating condition [2].

Therefore, according to this embodiment, compared to the comparative example in which the purge operation [1] is always performed assuming the occurrence of maximum color mixing, it is possible to reduce the amount of waste ink and the wiping time, thereby reducing running costs. , it becomes possible to improve productivity. That is, it becomes possible to realize more efficient purging operations.

In addition, as mentioned above, the time from when the circulation drive stops until the ink flow actually stops (circulation flow velocity remaining time) changes depending on the temperature at the start of wiping. also changes. For example, when the ink temperature was 60° C., the circulation flow velocity remaining time was about 15 seconds. That is, compared to the case where the ink temperature is 25° C., the circulation remaining time is shortened, and the circulation flow rate at the start of wiping is also reduced accordingly. In this case, it was possible to eliminate the color mixture of inks in the recording head 110 under both of the above-mentioned purge operation conditions [1] and [2]. Therefore, in this embodiment, the purge operation condition [2], in which the amount of ink discharged is small and the wiping time is short, is executed. In this way, in this embodiment, since the purge operation is determined in consideration of the ink temperature, it becomes possible to perform a more appropriate and efficient purge operation.

Note that in this embodiment, an example has been shown in which the purge operating conditions are determined by taking into account the temperature detected by the temperature sensor provided in the print head 110. It is also possible to determine the purge operation. For example, when comparing the case where the environmental temperature is 10° C. and the case where the environmental temperature is 30° C., there may be a difference in the circulation flow velocity remaining time. That is, when the environmental temperature is 10°C, the ink temperature tends to decrease, and the circulation flow rate remaining time tends to be longer than when the environmental temperature is 30°C. Therefore, by acquiring the environmental temperature as well as the ink temperature, and determining the remaining circulation flow rate time based on the temperature difference between the two, it will be possible to perform a more appropriate purge operation, and the effectiveness of the recording device will be improved. will further increase.

(Second embodiment)
Next, a second embodiment of the present disclosure will be described. In this embodiment, a purge operation control suitable for performing wiping by a wiping mechanism 550 equipped with a porous member (nonwoven fabric) wiper shown in FIG. 6 will be described.

As described above, the wiping mechanism 550 shown in FIG. 6B includes a sheet-like member 541 as a wiper capable of wiping off ink adhering to the ejection port surface of the recording head. A porous member such as a nonwoven fabric can more easily absorb ink from the ejection port during wiping than an elastic member, and therefore can provide a better wiping effect. In this embodiment, the length of the sheet-like member 541 that is brought into contact with the discharge port surface F by the pressing member is about 5 mm in the discharge port row direction (that is, the wiping direction).

<Relationship between wiping and purge operation control>
In this embodiment, more suitable purge operation control will be described for a case where a large amount of mixed color ink is generated in the print head. As described above, when the ink temperature is low, the circulation flow rate remaining time becomes long. However, if a waiting time is provided before wiping starts, a lot of time is required for the recovery operation from wiping to completion of the purge operation. Therefore, even in a situation where the amount of mixed color ink generated in the recording head 110 is expected to increase, in order to complete the recovery operation in about the same amount of time as when normal color mixing occurs, it is necessary to reduce the degree of color mixing. It is necessary to perform the purge operation immediately after color mixing while suppressing the color mixing.

In the first embodiment, the number of ejections and the ejection frequency in the purge operation performed after wiping is completed are controlled. In contrast, in this embodiment, control is performed to advance the start timing of the purge operation, suppressing the mixed color ink from penetrating deep into the flow path due to the circulation flow, and reducing the amount of ink discharged by the purge operation and the purge operation. Reduce time.

Specifically, while wiping is performed using the sheet-like member 541, a purge operation is performed on the sheet-like member 541. That is, by immediately discharging the mixed color ink, etc. that entered the ejection port through the wiping onto the sheet-like member 541, the color mixture is instantly eliminated. According to this, it becomes possible to discharge the mixed color ink etc. before it enters the depths of the flow path, and it becomes possible to eliminate problems such as color mixing with a smaller ejection amount.

For example, when wiping was performed at a speed of 100 mm/s, the time during which the sheet-like member 541 was in contact with the discharge port surface F due to wiping was about 0.3 seconds. Therefore, in this embodiment, purge discharge was performed on the seed member 541 for 0.3 seconds from the time when the sheet member 541 came into contact with the discharge port surface F. As a result, the mixed color ink that has entered through the ejection ports due to wiping can be immediately discharged onto the sheet-like member 541, and it is possible to maintain appropriate ejection performance while reducing the amount of ejection caused by the purge operation.

The above-mentioned operation will be explained according to the flowchart of FIG. Note that each process in the flowchart of FIG. 13 is executed by the CPU 302 shown in FIG. 2.

In S1301, the CPU 302 stops driving the circulation pump 408 as a circulation means, and then acquires a wiping start time Ti, which is the elapsed time from the stop of the circulation drive to the start of the wiping operation (S1302). Further, the CPU 302 obtains the ink temperature Te detected by the temperature sensor (S1303). Thereafter, the CPU 302 obtains the circulation flow velocity at the time of starting wiping based on the obtained wiping start time Ti and ink temperature Te (S1304). Thereafter, it is determined whether the difference between the circulating flow velocity remaining time and the wiping start time (circulating flow velocity remaining time - wiping start time) is shorter than a predetermined time (20 seconds in this embodiment) (S1305). In addition, the larger the difference between the circulation velocity remaining time and the wiping start time, the greater the circulation flow velocity at the start of wiping, and the smaller the difference, the lower the circulation flow velocity.If the difference is less than 0, the circulation flow velocity is 0. Become. In the determination in S1305, if it is determined that the difference between the circulating flow velocity remaining time and the wiping start time is equal to or greater than the predetermined time, the CPU 302 sets the ejection start timing by the purge operation so that ink is ejected onto the sheet-like member 541. Hurry up (S1307). Specifically, the purge operation is executed simultaneously with the start of wiping. As a result, the mixed color ink generated by wiping is immediately discharged onto the sheet-like member 541, and it becomes possible to eliminate the color mixture with a small amount of ejection.

On the other hand, if it is determined in S1305 that the difference between the circulating flow velocity remaining time and the wiping start time is shorter than the predetermined time, the CPU 302 starts the wiping operation in S1406. Thereafter, when the wiping operation is ended in S1304, the CPU 302 executes a purge operation according to the circulation flow rate obtained in S1304 described above (S1309). That is, the larger the obtained circulation flow velocity is, the larger the amount of ink discharged is performed.

(Other embodiments)
In the above-mentioned embodiment, a serial type printing apparatus using a circulation method in which ink is supplied and collected by the buffer tank 401 of the print head 110 mounted on the carriage 102 has been described as an example, but the present disclosure is not limited thereto. For example, the present disclosure discloses a full-line printing apparatus that holds a print head in a fixed position and performs a printing operation while continuously conveying a print medium, in which ink can be circulated and wiping can be performed. It is also applicable to those that take .

Further, in the above embodiment, an example was shown in which cleaning is performed by generating negative pressure in the cap 511 that can be brought into contact with and separated from the recording head 110 and sucking ink from the ejection ports 424. It is also possible to adopt the method. For example, it is also possible to perform a pressure recovery process as cleaning, in which positive pressure is applied within the recording head and ink is forcibly discharged from the ejection ports using the positive pressure.

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

Note that the present disclosure includes the following configurations, methods, and programs.

(Configuration 1)
A recording device that records an image by ejecting ink from an ejection port provided on an ejection port surface of a print head,
ejection means for performing preliminary ejection to eject ink from the ejection port in order to recover the ejection performance of the ejection port;
a flow means for flowing ink within a flow path communicating with the ejection port;
wiping means that performs a wiping operation on the discharge port surface;
acquisition means for acquiring the flow velocity of ink in the flow path at the start of the wiping operation;
A recording apparatus comprising: a control means for controlling the preliminary ejection based on the flow velocity acquired by the acquisition means.

(Configuration 2)
The recording apparatus according to configuration 1, wherein the control means performs the preliminary ejection such that the greater the flow velocity, the greater the degree of recovery of the ejection performance of the print head.

(Configuration 3)
The acquisition means includes a first elapsed time from when the driving of the flowing means stops until the wiping operation starts, and a second elapsed time from when the driving of the flowing means stops until the flow of ink in the flow path stops. According to configuration 1 or 2, the flow rate of ink in the flow path at the time of starting the wiping operation is acquired based on the first elapsed time and the second elapsed time. recording device.

(Configuration 4)
further comprising temperature acquisition means for acquiring the temperature of the ink in the recording head,
The acquisition means determines the amount of ink in the flow path at the start of the wiping operation based on the temperature of the ink in the recording head detected by the temperature acquisition means, a first elapsed time, and a second elapsed time. The recording device according to configuration 3, wherein the recording device acquires a flow velocity.

(Configuration 5)
4. The recording apparatus according to configuration 4, wherein the temperature acquisition means acquires at least the temperature of the ink when driving of the flow means is stopped.

(Configuration 6)
The temperature acquisition means further acquires an environmental temperature around the recording device,
A flow velocity of the ink in the flow path at the time of starting the wiping operation is obtained based on a temperature difference between the temperature of the ink and the environmental temperature, a first elapsed time, and a second elapsed time. 6. The recording device according to configuration 4 or 5.

(Configuration 7)
The temperature acquisition means includes a plurality of temperature detection means arranged at a plurality of locations within the recording head, and determines the lowest temperature among the plurality of temperatures detected by each of the plurality of temperature detection means as the temperature of the ink within the recording head. 7. The recording device according to any one of configurations 4 to 6, wherein the recording device acquires the information as follows.

(Configuration 8)
8. The recording apparatus according to any one of configurations 1 to 7, wherein the wiping means is constituted by an elastic member that moves while contacting the ejection port surface.

(Configuration 9)
8. The recording apparatus according to any one of configurations 1 to 7, wherein the control means causes the ejection means to perform the preliminary ejection while the wiping means is performing the wiping operation.

(Configuration 10)
The wiping means includes a porous member that moves while contacting the discharge port surface,
10. The recording apparatus according to configuration 9, wherein the control means causes the porous member to perform the wiping operation and causes the ejection means to perform the preliminary ejection.

(Configuration 11)
11. The recording apparatus according to configuration 10, wherein the control means starts the preliminary ejection so that the ink ejected by the preliminary ejection lands on the porous member.

(Configuration 12)
The porous member is constituted by a belt-like sheet-like member,
The wiping means includes the sheet-like member, a pressing member that brings a part of the sheet-like member into contact with the discharge port surface, and a sheet movement that moves the sheet-like member in the longitudinal direction with respect to the pressing member. 12. The recording device according to configuration 11, comprising: means.

(Configuration 13)
The recording head includes a supply channel for supplying ink to the channel, a recovery channel for recovering ink from the channel, and a connection to the supply channel and the recovery channel. an ink circulation flow path including an ink supply source;
Any one of configurations 1 to 12, wherein the ink supply source supplies ink to the flow path via the supply flow path and collects ink from the flow path via the recovery flow path. Recording device described in .

(Configuration 14)
A discharge port array is formed on the discharge port surface by a plurality of the discharge ports arranged along the first direction,
The recording head performs recording on a recording medium by ejecting ink from each ejection port of the ejection port array while moving along a second direction intersecting the first direction,
13. The recording apparatus according to any one of configurations 1 to 12, wherein the wiping means performs the wiping operation by moving along the first direction.

(Configuration 15)
15. The recording apparatus according to configuration 14, wherein a plurality of ejection port arrays corresponding to a plurality of colors of ink are arranged on the ejection port surface along a direction intersecting the first direction.

(Configuration 16)
16. The recording apparatus according to configuration 14 or 15, wherein the recording head is mounted on a carriage that moves along the first direction.

(Method 1)
A method for controlling a recording apparatus that records an image by ejecting ink from an ejection port provided on an ejection port surface of a print head, the method comprising:
performing preliminary ejection to eject ink from the ejection port in order to recover the ejection performance of the ejection port;
a step of causing ink to flow in a flow path communicating with the ejection port;
performing a wiping operation on the discharge port surface;
acquiring the flow velocity of ink in the flow path at the start of the wiping operation;
controlling the preliminary discharge based on the obtained flow rate;
A method for controlling a recording device, comprising:

(Program 1)
A program for causing a computer to execute each step described in Method 1.

100 Recording device 302 CPU
408 Circulation pump 423 Discharge element 424 Discharge port 530 Wiping mechanism

Claims (18)

A recording device that records an image by ejecting ink from an ejection port provided on an ejection port surface of a print head,
ejection means for performing preliminary ejection to eject ink from the ejection port in order to recover the ejection performance of the ejection port;
a flow means for flowing ink within a flow path communicating with the ejection port;
wiping means that performs a wiping operation on the discharge port surface;
acquisition means for acquiring the flow velocity of ink in the flow path at the start of the wiping operation;
A recording apparatus comprising: a control means for controlling the preliminary ejection based on the flow velocity acquired by the acquisition means. 2. The printing apparatus according to claim 1, wherein the control unit performs the preliminary ejection in such a manner that the greater the flow velocity, the greater the degree of recovery of the ejection performance of the print head. The acquisition means includes a first elapsed time from when the driving of the flowing means stops until the wiping operation starts, and a second elapsed time from when the driving of the flowing means stops until the flow of ink in the flow path stops. 3. The method of claim 1 or 2, further comprising acquiring a time, and acquiring a flow velocity of ink in the flow path at the time of starting the wiping operation based on the first elapsed time and the second elapsed time. Recording device as described. further comprising temperature acquisition means for acquiring the temperature of the ink in the recording head,
The acquisition means determines the amount of ink in the flow path at the start of the wiping operation based on the temperature of the ink in the recording head detected by the temperature acquisition means, a first elapsed time, and a second elapsed time. 4. The recording device according to claim 3, wherein the recording device acquires flow velocity. 5. The recording apparatus according to claim 4, wherein the temperature acquisition means acquires at least the temperature of the ink when driving of the flow means is stopped. The temperature acquisition means further acquires an environmental temperature around the recording device,
A flow velocity of the ink in the flow path at the time of starting the wiping operation is obtained based on a temperature difference between the temperature of the ink and the environmental temperature, a first elapsed time, and a second elapsed time. 5. The recording device according to claim 4. The temperature acquisition means includes a plurality of temperature detection means arranged at a plurality of locations within the recording head, and determines the lowest temperature among the plurality of temperatures detected by each of the plurality of temperature detection means as the temperature of the ink within the recording head. 5. The recording device according to claim 4, wherein the recording device acquires the information as follows. 2. The recording apparatus according to claim 1, wherein the wiping means is constituted by an elastic member that moves while contacting the ejection port surface. 2. The recording apparatus according to claim 1, wherein the control means causes the ejection means to perform the preliminary ejection while the wiping means is performing the wiping operation. The wiping means includes a porous member that moves while contacting the discharge port surface,
10. The recording apparatus according to claim 9, wherein the control means causes the porous member to perform the wiping operation and causes the ejection means to perform the preliminary ejection. 11. The recording apparatus according to claim 10, wherein the control means starts the preliminary ejection so that the ink ejected by the preliminary ejection lands on the porous member. The porous member is constituted by a belt-like sheet-like member,
The wiping means includes the sheet-like member, a pressing member that brings a part of the sheet-like member into contact with the discharge port surface, and a sheet movement that moves the sheet-like member in the longitudinal direction with respect to the pressing member. 12. The recording device according to claim 11, comprising: means. The recording head includes a supply channel for supplying ink to the channel, a recovery channel for recovering ink from the channel, and a connection to the supply channel and the recovery channel. an ink circulation flow path including an ink supply source;
Recording according to claim 1, characterized in that the ink supply source supplies ink to the flow path via the supply flow path and collects ink from the flow path via the recovery flow path. Device. A discharge port array is formed on the discharge port surface by a plurality of the discharge ports arranged along the first direction,
The recording head performs recording on a recording medium by ejecting ink from each ejection port of the ejection port array while moving along a second direction intersecting the first direction,
The recording apparatus according to claim 1, wherein the wiping means performs the wiping operation by moving along the first direction. 15. The recording apparatus according to claim 14, wherein a plurality of ejection port arrays corresponding to a plurality of colors of ink are arranged on the ejection port surface along a direction intersecting the first direction. 16. The recording apparatus according to claim 14, wherein the recording head is mounted on a carriage that moves along the first direction. A method for controlling a recording apparatus that records an image by discharging ink from an ejection port provided on an ejection port surface of a print head, the method comprising:
performing preliminary ejection to eject ink from the ejection port in order to recover the ejection performance of the ejection port;
a step of causing ink to flow in a flow path communicating with the ejection port;
performing a wiping operation on the discharge port surface;
acquiring the flow velocity of ink in the flow path at the start of the wiping operation;
controlling the preliminary discharge based on the obtained flow rate;
A method for controlling a recording device, comprising: A program for causing a computer to execute each step according to claim 17.

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