Recording device and control method thereof

Abstract

To suppress degradation in image quality by leakage of ink from a discharge port after wiping.SOLUTION: A recording device includes: a carriage which is mounted with a recording head for discharging ink, and reciprocates with respect to a recording medium; a wiping part which wipes a discharge port surface formed with an ink discharge port of the recording head; and control means which controls moving operation of the carriage and wiping operation of the wiping part so that when deceleration when the carriage is stopped is first deceleration, time until the wiping part starts wiping of the discharge port surface after the carriage is stopped is defined as first time, when the deceleration when the carriage is stopped is second deceleration smaller than the first deceleration, time until the wiping part starts the wiping of the discharge port surface after the carriage is stopped is defined as second time shorter than the first time.SELECTED DRAWING: Figure 9A

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus provided with a means for wiping a discharge port surface. [Background technology]

[0002] In conventional inkjet recording devices that record by reciprocating an inkjet print head mounted on a carriage, larger ink tanks are required to reduce the frequency of ink tank replacement. However, in systems where the inkjet print head and ink tank are integrated, mounting a large ink tank on the carriage increases the carriage's inertia. For this reason, inkjet recording devices are known in which the ink tank is located in a stationary position rather than on a moving object such as the carriage. A supply tube connects the ink tank to the print head on the carriage, and ink is supplied from the ink tank to the print head.

[0003] In the above configuration, it is known that when the ink in the supply tube vibrates as the carriage moves, dynamic pressure is applied to the ink due to inertia. Patent Document 1 discloses a configuration in which the dynamic pressure of the ink generated in the tube is used to control the acceleration of the carriage to fill the ink into a sub-tank. The sub-tank is an ink storage unit located between the main tank and the print head.

[0004] On the other hand, in inkjet recording devices, fine droplets generated during ink ejection or ink rebounding from the recording medium may adhere to the ejection orifice surface. Such deposits may clog the ejection orifices or may come into contact with the ejected ink droplets, causing a decrease in the quality of the recorded image. To prevent such recording defects, a method has been known in the past to wipe (hereinafter also referred to as "wiping") the ejection orifice surface with a blade or the like to remove adhering ink droplets, etc. Patent Document 2 discloses an inkjet recording device that wipes the ejection orifice surface of the recording head during and after recording (after the recording paper is ejected). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-226738 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-094701 Summary of the Invention [Problem to be solved by the invention]

[0006] When ink flows from the supply tube into the print head due to dynamic pressure acting on the ink in the supply tube, the internal pressure of the print head increases. Patent Document 1 states that this ink dynamic pressure is proportional to the carriage acceleration / deceleration, and the same is true for the internal pressure of the print head. That is, depending on the magnitude of acceleration / deceleration, the internal pressure of the print head may become positive after the carriage stops. Patent Document 2 describes wiping being performed after the carriage stops. In this case, the convex meniscus formed at the ejection port is broken by the wiping member, and the subsequent movement of the carriage may cause ink to drip from the ejection port onto the print medium, etc., thereby degrading the quality of the printed image.

[0007] In addition, the internal pressure of the print head decreases from positive to negative during the operation time of the wiper, such as raising and lowering, after the carriage has stopped and before the wiping operation is performed, thereby preventing ink leakage.

[0008] On the other hand, if the carriage movement speed is increased to improve throughput, the carriage acceleration and deceleration speed must also be increased, which increases the range of increase and decrease in the internal pressure of the print head.

[0009] In particular, when performing a printing operation at high speed, there is a possibility that the time for the internal pressure of the print head to decrease from positive to negative pressure before the wiping operation is performed may not be sufficient.

[0010] The present invention has been made in view of the above-mentioned problems, and has an object to suppress deterioration in image quality due to leakage of ink from ejection ports after wiping. [Means for solving the problem]

[0011] The recording device according to the present invention is characterized by comprising: a carriage carrying a recording head that ejects ink and that moves back and forth relative to a recording medium; wiping means that wipes an ejection port surface on which ink ejection ports of the recording head are formed; and control means that controls the movement of the carriage and the wiping operation of the wiping means so that, when the deceleration rate at which the carriage is stopped is a first deceleration rate, the time from when the carriage stops until when the wiping means starts wiping the ejection port surface is a first time; and, when the deceleration rate at which the carriage is stopped is a second deceleration rate that is smaller than the first deceleration rate, the time from when the carriage stops until when the wiping means starts wiping the ejection port surface is a second time that is shorter than the first time. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress a decrease in image quality due to ink leakage from the ejection ports after wiping. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the overall configuration of an inkjet recording apparatus according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram of a recording head according to the first embodiment. [Figure 3A] FIG. 3 is a schematic diagram of a recovery unit according to the first embodiment. [Figure 3B] FIG. 3 is a schematic diagram of a recovery unit according to the first embodiment. [Figure 3C] FIG. 3 is a schematic diagram of a recovery unit according to the first embodiment. [Figure 3D] FIG. 3 is a schematic diagram of a recovery unit according to the first embodiment. [Figure 3E]FIG. 3 is a schematic diagram of a recovery unit according to the first embodiment. [Figure 4] FIG. 2 is a schematic cross-sectional view showing an ink flow path for one color of the ink jet recording apparatus according to the first embodiment. [Figure 5] FIG. 2 is a block diagram showing a control configuration in the first embodiment. [Figure 6] 4A and 4B are diagrams showing a carriage speed profile and an internal pressure profile of a recording head. [Figure 7A] FIG. 4 is a schematic diagram of the print head and supply tube when the carriage is scanning. [Figure 7B] FIG. 4 is a schematic diagram of the print head and supply tube when the carriage is scanning. [Figure 7C] FIG. 4 is a schematic diagram of the print head and supply tube when the carriage is scanning. [Figure 8A] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 8B] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. [Figure 8C] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 8D] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. [Figure 8E] FIG. 2 is a cross-sectional view of the vicinity of the ejection ports of the print head. [Figure 8F] FIG. 2 is a cross-sectional view of the vicinity of the ejection ports of the print head. [Figure 8G] FIG. 2 is a cross-sectional view of the vicinity of the ejection ports of the print head. [Figure 8H] FIG. 2 is a cross-sectional view of the vicinity of the ejection ports of the print head. [Figure 9A] 5 is a flowchart showing a wiping operation in the first embodiment. [Figure 9B] FIG. 4 is a diagram showing a wait time in the first embodiment. [Figure 10] 10A and 10B are diagrams showing a velocity profile of a carriage and an internal pressure profile of a print head in the second embodiment. [Figure 11] Vector diagram of the scanning during recording. [Figure 12] 10A and 10B are diagrams showing a velocity profile of a carriage and an internal pressure profile of a print head in the second embodiment. [Figure 13A] 10 is a flowchart showing a wiping operation in the second embodiment. [Figure 13B] FIG. 10 is a diagram showing the deceleration of the carriage immediately before wiping in the second embodiment. [Figure 14A] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 14B] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. [Figure 14C] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 14D] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. [Figure 15A] 10 is a flowchart showing a wiping operation in the third embodiment. [Figure 15B] FIG. 11 is a diagram showing a wait time in the third embodiment. [Figure 16A] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 16B] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. [Figure 16C] FIG. 10 is a diagram showing a velocity profile after the carriage starts to decelerate. [Figure 16D] FIG. 10 is a diagram showing the internal pressure profile of the carriage after the carriage starts to decelerate. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0015] In this specification, "recording" refers not only to the formation of meaningful information such as characters and figures, but also to the formation of meaningful or insignificant information. Furthermore, "recording" broadly refers to the formation of images, designs, patterns, etc. on a recording medium, or the processing of a medium, regardless of whether the information is visible to humans. Furthermore, "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 film, metal plates, glass, ceramics, wood, and leather. Furthermore, "ink" (sometimes referred to as "liquid") should be interpreted broadly, similar to the definition of "recording" above. Therefore, it refers to a liquid that can be applied to a recording medium to form images, designs, patterns, etc., or to process the recording medium, or to process ink (for example, to solidify or insolubilize coloring materials in ink applied to the recording medium). Furthermore, unless otherwise specified, "nozzle" collectively refers to an ejection port, a liquid path connected to the ejection port, and an element that generates energy used to eject ink.

[0016] (First embodiment) An inkjet recording apparatus according to a first embodiment of the present invention will be described in detail below with reference to the drawings.

[0017] FIG. 1 is a schematic perspective view of the main recording components of a serial scan recording device according to this embodiment. In FIG. 1, a carriage 104 holds a recording head 101 and moves relative to a recording medium 105 in a main scanning direction indicated by coordinate axis X (main scanning direction). The carriage 104 is driven by a carriage motor (not shown) attached to the inkjet recording device body, pulling a drive belt (not shown) fixed on the carriage 104. As the transport roller 106 rotates, it transports the recording medium 105 in a sub-scanning direction indicated by coordinate axis Y (sub-scanning direction). An image is formed on the recording medium in stages by alternating between the main scanning, in which the carriage 104 moves in the main scanning direction while the recording head 101 ejects ink in accordance with recording data, and the transport operation of the recording medium associated with the rotation of the transport roller 106. As ink in the recording head 101 is consumed during the recording operation, ink is supplied from an ink supply system 108 via a supply tube 102. The ink supply system 108 is provided with a plurality of ink tanks 103, each containing a different color of ink.

[0018] The recovery unit 107 is disposed outside the printing area in the movement direction of the carriage 104. The carriage 104 stops at a home position outside the printing area before the start of a printing operation or during a printing operation as necessary. The home position refers to the rightmost position in the drawing in the main scanning direction of the carriage. The leftmost position in the drawing in the main scanning direction of the carriage is the back position. The recovery unit 107 is disposed in a position facing the print head 101 when the carriage 104 stops at the home position. The recovery unit 107 performs a cleaning operation by sucking ink and air from the multiple ejection ports provided in the ejection port surface 200 of the print head 101 as necessary, and performs a wiping operation to remove ink and foreign matter adhering to the ejection port surface.

[0019] FIG. 2 is a schematic diagram of a print head according to this embodiment. FIG. 2 is a view of the print head 101 as viewed from the ink ejection direction (bottom). The print head 101 has a print port surface (nozzle surface) 200 provided with a plurality of print port arrays (nozzle arrays) 201-206, each of which has a plurality of print port (nozzle) ejecting ink. The print port arrays 201-206 are arranged in a line along the movement direction of the carriage 104, so as to be capable of ejecting ink of different tones (including colors and densities). For example, the print port arrays 201-206 are arranged in a line along the movement direction of the carriage 104, so as to be capable of ejecting black (Bk), light cyan (Lc), cyan (C), light magenta (Lm), magenta (M), and yellow (Y) ink. Each print port receives ink from an ink introduction section 207, which is connected to an ink tank (not shown) via a tube, via an ink flow path within the print head. The print head 101 of this embodiment is an inkjet print head that ejects ink using thermal energy and is equipped with a plurality of electrothermal converters for generating thermal energy. That is, the print head 101 generates thermal energy by applying a pulse signal to the electrothermal converters, and this thermal energy causes film boiling of ink in an ink bubbling chamber (not shown), and the bubbling pressure of the film boiling is used to eject ink from the ejection orifices. Note that the ink ejection method is not limited to this, and may also be a method using a piezoelectric element.

[0020] 3A and 3B are schematic diagrams of the recovery unit 107 according to this embodiment. The recovery unit 107 includes a cap 302 that covers the nozzle surface of the print head 101, a suction pump 303 that sucks ink from the print head while the cap 302 covers the nozzle surface, and a wiper 301 that wipes the nozzle surface of the print head. The cap 302 is supported by a lifting mechanism (not shown) so that it can move up and down between a raised position and a lowered position. In the raised position, the cap 302 abuts against the print head 101 and covers (caps) the nozzle surface 200 of the print head 101. By covering the nozzle surface 200, the cap 302 can prevent the nozzles of the print head 101 from drying out and evaporating ink during non-printing operations, or can suck ink from the print head 101 by driving a suction pump 303 (described later).

[0021] During printing, the cap 302 is positioned in a lowered position to avoid interference with the print head 101, which moves together with the carriage 104. With the cap 302 in the lowered position, the print head 101 can perform preliminary ejection onto the cap 302 when it moves to a position facing the cap 302. The wiper 301 moves back and forth between a wiping position and a retracted position in the direction of arrow Z by well-known means to contact and retract from the print port surface 200 to remove foreign matter such as ink residue adhering to the print port surface 200. That is, when not wiping, the wiper 301 is positioned in the retracted position as shown in FIG. 3A. On the other hand, during wiping, the wiper 301 moves to the wiping position as shown in FIG. 3B, and in that state, the carriage 104 moves in the direction of arrow X, causing the wiper 301 to wipe the print port surface 200.

[0022] The suction pump 303 is driven when the cap 302 covers the ejection port surface 200 of the print head 101, creating a substantially sealed space inside, and generates negative pressure inside to perform a suction operation that sucks ink from the print head 101. This suction operation is performed when filling the print head 101 with ink from the ink tank 103 (initial filling) and when sucking and removing dust, solidified matter, air bubbles, etc. from inside the ejection ports (suction recovery). The cap 302 is connected to a waste ink absorber (not shown) via a flexible tube 304.

[0023] In this embodiment, the wiper 301 is made of an elastic material such as rubber, but it may also be made of a sheet-like porous material that absorbs ink. Porous materials are more likely to absorb and draw ink from the ejection ports during wiping than elastic materials, and therefore the effects of this embodiment are more pronounced. Schematic diagrams of the recovery unit 107, which is equipped with a wiping unit 309 made of a sheet-like porous material, are shown in Figures 3C and 3D.

[0024] The wiping unit 309 is made of a porous body formed in the shape of an elongated sheet, and is provided with a liquid-impregnated member (wiping member) 305 that is pre-impregnated with a wiping liquid whose main component is a low-volatility solvent such as polyethylene glycol. Hereinafter, this liquid-impregnated member (wiping member) 305 will also be referred to as a "sheet member."

[0025] The sheet member 305, which is formed in the shape of an elongated sheet, has one end wound in a roll around a first core material 307 and the other end wound in a roll around a second core material 308. The sheet member 305 is arranged so that the portion that is not wound in a roll (hereinafter referred to as the "non-rolled portion") faces the ink ejection orifice surface 200 when the recording head 101 moves back and forth. In other words, the non-rolled portion of the sheet member 305 is arranged vertically above the first core material 307 and the second core material 308.

[0026] The back surface of the non-roll portion of the sheet member 305 (the surface opposite to the surface facing the ink ejection port surface 200) is supported by a support member 306 made of an elastic material. The support member 306 moves back and forth between a wiping position and a retracted position in the direction of arrow Z by well-known means to contact and retract from the ejection port surface 200 in order to remove foreign matter such as ink residue adhering to the ejection port surface 200. That is, when not wiping, the support member 306 is located in the retracted position as shown in FIG. 3C. On the other hand, when wiping, the support member 306 moves to the wiping position as shown in FIG. 3D, and in this state, the carriage 104 moves in the direction of arrow X to perform the wiping operation.

[0027] The first core 307 is driven by a conveyance motor for the sheet member 305 and is configured to rotate in the R direction in FIGS. 3C and 3D. This allows the sheet member 305 to be conveyed in the same direction as the forward direction of the carriage 104 (see the arrow X direction). Meanwhile, the second core 308 is rotated in conjunction with the rotation of the first core 307, but the first core 307 is provided with a known torque limiter to prevent rotation when the support member 306 moves back and forth in the vertical direction. The conveyance length (conveyance amount) of the sheet member 305 is controlled by the amount of rotation of the conveyance motor, but may also be controlled based on the measurement results of a conveyance length measurement means using known means, for example, optical means. In this case, it is preferable that a scale (gradation) for measuring length is provided on the end of the sheet member 305 along the conveyance direction.

[0028] Furthermore, in this embodiment, the wiping direction is the direction in which the nozzle rows in the print head are arranged, but it may also be configured to move in a direction intersecting (orthogonal to) this direction (the direction in which the nozzles are arranged). A schematic diagram of a recovery unit configured so that the wiper moves in the direction in which the nozzles are arranged is shown in Figure 3E. Figure 3E is a view seen from the +Z direction in Figure 1.

[0029] In this embodiment, two wipers 310 and 311 are provided, each wiping three nozzle arrays (201-203, 204-206) in FIG. 2 , and a wiper 312 is provided for wiping the entire nozzle surface including the nozzle arrays 201-206. The wipers 310 and 311 are fixed to a wiper holder 313. The wiper holder 313 is movable in the forward and backward directions indicated by the Y direction in the figure (the direction in which the nozzles are arranged in the print head 101). When the print head 101 is positioned at the home position, the wiper holder 313 moves in the +Y direction (one direction), allowing the wipers 310 and 311 to perform a wiping operation in which they abut against the nozzle surface and wipe the nozzle surface. When the wiping operation is completed, the carriage 104 is moved out of the wiping operation area and retracted, and then the wiper holder 313 is moved back to its original position (the position before the wiping operation).

[0030] In the configuration shown in FIG. 3E, the wiper is not limited to an elastic member such as rubber, and may be a member made of a porous material that absorbs ink.

[0031] Furthermore, in this embodiment, the wiper is configured to perform wiping only when it moves in one direction, but the wiper may be configured to perform wiping when it moves back and forth in both directions.

[0032] Figure 4 is a view of the main recording section in Figure 1 as seen from the +Y direction. Figure 4 shows a serial scan type inkjet recording device in which an ink tank 103 is arranged at a fixed position in the main body of the inkjet recording device and ink is supplied to a recording head 101 on a carriage 104 via a tube 102. The ink path from the ink tank 103 to the recording head 101 is also shown. The supply tube 102 is arranged so that it has a section that is approximately parallel to the direction of movement of the carriage 104. Note that the arrangement of the supply tube 102 shown in Figure 4 is merely an example and is not limited to this.

[0033] The ink supply system 108 is held and fixed at a predetermined position in the recording apparatus body. In this embodiment, a sub-tank 407 is provided vertically below the ink tank 103, and the sub-tank 407 is provided with a first hollow tube 404 and a second hollow tube 405 that extend vertically upward. The sub-tank 407 also has an air vent port 406. The ink tank 103 also has a first joint portion 402 and a second joint portion 403 at its bottom. By inserting the first hollow tube 404 into the first joint portion 402 and the second hollow tube 405 into the second joint portion 403, the ink tank 103 is connected to the atmosphere via the air vent port 406.

[0034] The print head 101 is connected to a subtank 407, which stores ink, via a supply tube 102. During printing, as ink is consumed in the print head 101 by ejecting ink from each ejection port, ink is supplied from the subtank 407 via the supply tube 102 as needed. When the ink in the subtank 407 is consumed, the liquid level in the subtank 407 first drops. This causes the bottom end of the first hollow tube 404 to separate from the ink liquid level in the subtank 407, so that the ink tank 103 communicates with the atmosphere via the first hollow tube 404. As a result of communication with the atmosphere, air is discharged from the atmosphere communication port 406, the ink liquid level in the ink tank 103 drops, and the subtank 407 is refilled with ink. When the liquid level rises to the same vertical position as indicated by B in Figure 4, the lower end of the first hollow tube 404 is again blocked with ink, and the movement of ink from the ink tank 103 to the subtank 407 stops, i.e., filling is completed.

[0035] Additionally, the vertical position of the subtank 407 is set so that the ink level in the subtank 407 is lower in the direction of gravity than the ejection port surface 200 of the print head 101. Therefore, the pressure inside the print head 101 is maintained at a negative pressure due to a so-called head difference. The vertical position of the subtank 407 is also set so that this negative pressure does not destroy the meniscus formed at the ink ejection ports. In this embodiment, the height difference between the ejection port surface 200 and the ink level in the subtank 407, the so-called head difference H, is approximately 80 mm. An on-off valve 408 is disposed in the supply tube 102 adjacent to the subtank 407 to open and close the ink passage formed by the supply tube 102. When transporting the inkjet printing apparatus, closing the on-off valve 408 prevents ink from leaking or dripping from the ejection ports. This concludes the outline of the ink supply system using the head difference method in this embodiment.

[0036] Other ink supply methods include a pressure method using a regulator, and the effects of this embodiment can be achieved with any supply method. In particular, the head difference method controls the internal pressure of the print head only by the head difference, and the pressure fluctuation effect caused by the ink dynamic pressure generated by carriage movement is significant, so the effects of this embodiment are more pronounced.

[0037] Next, a control configuration for executing print control of the inkjet printing apparatus will be described. Fig. 5 is a block diagram for explaining the configuration of a control system of the inkjet printing apparatus shown in Fig. 1.

[0038] 5, first, multi-value image data stored in an image input device 501 such as a scanner or digital camera or in various storage media such as a hard disk is input to an image input unit 502. The image input unit 502 is a host computer connected to the outside of the recording device, and transfers image information to be recorded to an image output unit 504, which is a recording device, via an interface circuit 503. The image input unit 502 is provided with a CPU 505 and a memory element (ROM 506) required for transferring image data. The host computer may take the form of an information processing computer or may take the form of an image reader, etc.

[0039] The recording control unit 507 contains a CPU 508, an input / output port 509, a memory element (ROM 510) that stores control programs and the like, a RAM 511 that serves as a work area when performing various image processing, and a non-volatile memory NVRAM 512. The ROM 510 stores various data such as the control program for the CPU 508 and parameters required for recording operations. The RAM 511 is used as a work area for the CPU 508 and also temporarily stores various data such as image data received from the image input unit 502 and generated recording data. An image is then formed by applying ink from the orifices of the recording head 101 to a recording medium based on the image data converted by the recording control unit 507.

[0040] Also connected to the recording control unit 507 via an input / output port 509 are various motors 518 for operating the carriage and LF (line feed), a suction operation motor 519, the recording head 101, and their respective drive circuits 513, 514, and 515. The suction operation motor 519 is a drive source for operating the suction pump 303 for sucking and discharging ink from the recording head 101 described in FIG. 2. Furthermore, sensors such as a temperature / humidity sensor 521 for detecting the temperature and humidity of the surrounding environment and their drive circuit 517 are connected to the input / output port 509. Also connected is a display / operation unit controller 516 for controlling the display unit and operation unit 520 of the inkjet recording apparatus.

[0041] Next, the fluctuation in the internal pressure of the print head 101 due to the movement of the carriage 104 will be described.

[0042] FIG. 6(a) shows an example of a carriage speed profile when the carriage 104 makes one reciprocating scan from the home position side and performs wiping. FIG. 6(b) shows an example of an internal pressure profile of the print head at that time. In FIG. 6(a), the horizontal axis represents time and the vertical axis represents carriage speed. The speed when moving in the positive direction of the X axis in FIG. 1 is considered positive. In FIG. 6(b), the horizontal axis represents time and the vertical axis represents the internal pressure of the print head.

[0043] 7A shows a schematic diagram of the arrangement of the supply tube 102 at time 0 in FIG. 6A. This is the moment when the carriage 104 starts scanning from the home position side, and the speed is 0.

[0044] During period A in FIG. 6(a), the carriage 104 starts moving from the home position side and accelerates until it reaches a predetermined speed V1. In this embodiment, it accelerates until it reaches a speed of 60 inches / s. When the carriage 104 accelerates on the home position side as shown in FIG. 7(A), ink dynamic pressure is generated by inertial force in the direction from the subtank 407 toward the print head 101. The generated ink dynamic pressure moves the ink in the tube toward the print head 101, so the pressure inside the print head 101 increases. During period A in FIG. 6(b), the internal pressure of the print head 101 increases to P1. In this embodiment, it increases to +10 mmAq.

[0045] Next, during period B, the carriage 104 moves at a constant speed V1. At this time, because no inertial force acts on the ink, the internal pressure of the print head 101 gradually decreases toward the reference pressure P0. The reference pressure P0 here refers to the internal pressure of the print head 101 when the carriage 104 is stationary, and in this embodiment is set to -80 mmAq. Because the internal pressure of the print head 101 has increased during period A, during period B in Figure 6(b), the internal pressure of the print head 101 decreases toward the reference pressure P0.

[0046] Next, during periods C and D, the carriage 104 decelerates at the back position, reverses direction, then accelerates, moving in the opposite direction at a velocity V2. In this embodiment, velocity V2 is also set to 60 inches / s. Figure 7B shows a schematic diagram of the arrangement of the supply tube 102 at time TC in Figure 6(a). When the carriage 104 decelerates at the left end of the main scanning direction and then accelerates in the opposite direction, ink dynamic pressure is generated in the ink in the tube due to inertial force in the direction from the print head 101 to the subtank 407. The generated ink dynamic pressure causes the ink in the tube to move back toward the subtank 407, decreasing the pressure inside the print head 101. During periods C and D in Figure 6(b), the internal pressure of the print head 101 decreases to P2. In this embodiment, the decrease is to -85 mmAq.

[0047] Next, in period E, the carriage 104 moves at a constant speed, just like in period B. Because the internal pressure of the print head 101 decreases in period D, the internal pressure of the print head 101 increases toward the reference pressure P0 in period E in FIG. 6B. Next, to perform wiping after the carriage 104 stops, the carriage 104 must stop on the recovery unit 107. Therefore, the carriage scanning distance during period E is longer than the carriage scanning distance during period B. Therefore, the duration of period E is longer than the duration of period B.

[0048] Finally, during period F, the carriage 104 is decelerated to stop it at a position above the recovery unit 107. The position of the supply tube 102 at time TF (the time the carriage stops) in FIG. 6(a) is shown in FIG. 7C. The carriage 104 stops above the recovery unit 107 to perform wiping. Because the inertial force acts in the same direction as during period A, the internal pressure of the print head 101 rises to P1 during period F in FIG. 6(b). This completes the explanation of pressure fluctuations due to carriage movement. Hereinafter, the acceleration during deceleration will be referred to as "deceleration."

[0049] As described above, the internal pressure of the print head 101 is likely to become positive on the home position side where the recovery unit 107 is located. Therefore, the effect of this embodiment is greater when the supply tube 102 is connected from the back position side. Here, the dynamic pressure of the ink in the tube is Pn=(mn·an) / S …Equation (1) mn: mass of ink under acceleration S: cross-sectional area of supply tube an: Carriage acceleration In this case, the ink mass when the maximum dynamic pressure occurs is mn=k·S·Ln …Formula (2) k: specific gravity of ink S: cross-sectional area of supply tube Ln: Maximum length of supply tube subjected to inertia due to acceleration It can be expressed as:

[0050] By substituting equation (2) into equation (1), Pn=k·Ln·an …Equation (3) The relationship is as follows.

[0051] Here, acceleration is the difference between the carriage speed at the start of acceleration and the carriage speed at the end of acceleration divided by the acceleration time. Similarly, deceleration is the difference between the carriage speed at the start of deceleration and the carriage speed at the end of deceleration divided by the deceleration time. In both cases, the positive direction of the X-axis in Figure 1 is considered positive.

[0052] From equation (3), we can see that ink dynamic pressure is proportional to acceleration / deceleration. Acceleration / deceleration is mainly affected by the carriage speed during printing. If the carriage speed is increased to improve throughput, the acceleration / deceleration also increases. Conversely, if the carriage speed is decreased to improve image quality, the acceleration / deceleration also decreases.

[0053] Furthermore, equation (3) shows that ink dynamic pressure is also proportional to the maximum length of the tube that is subjected to inertia due to acceleration. Therefore, in an inkjet recording device with tubes arranged as shown in Figure 4, when the carriage 104 accelerates or decelerates on the home position side, the fluctuation range of the pressure generated inside the recording head 101 is larger than when the carriage 104 accelerates or decelerates on the back position side. This is because the maximum length of the supply tube that is subjected to inertia is longer (L701 > L702) when the carriage 104 accelerates or decelerates on the home position end side as shown in Figure 7A than when the carriage 104 accelerates or decelerates on the back position side as shown in Figure 7B.

[0054] For these reasons, the increase in the internal pressure of the print head due to carriage acceleration / deceleration at the home position may be greater than the decrease in the internal pressure of the print head due to carriage acceleration / deceleration at the back position, and the increase in the internal pressure of the print head during constant speed movement. In this case, the internal pressure of the print head due to carriage acceleration / deceleration at the home position remains above the reference pressure P0.

[0055] The effect of this embodiment can also be seen in a system in which the print head and ink tank are integrated, provided that part of the ink flow path has a section that is approximately parallel to the direction of carriage movement. However, the effect of this embodiment is more pronounced in a system in which ink is supplied from the ink tank to the print head through a supply tube.

[0056] Next, a control for setting a wait time from when the carriage stops until the wiping operation starts, which is a feature of this embodiment, will be described.

[0057] The carriage, which was moving at a speed of V801, decelerates at a rate of a801 (inches / second) 2 8A shows the carriage velocity profile when the carriage decelerates at a speed V802 and stops on the recovery unit at a deceleration a802 (inches / sec), and the time when the internal pressure of the print head becomes 0 is T801b. The internal pressure profile of the print head in this case is shown in FIG. 8B. 2) (a802>a801) and stops on the recovery unit, time T802a, and time T802b when the internal pressure of the print head becomes 0. The internal pressure profile of the print head in this case is shown in Figure 8D. In Figures 8A and 8C, the horizontal axis represents time, and the vertical axis represents carriage speed. Also, the speed when moving in the positive direction of the X-axis in Figure 1 is considered positive. In Figures 8B and 8D, the horizontal axis represents time, and the vertical axis represents internal pressure of the print head.

[0058] As shown in Figures 8B and 8D, the internal pressure of the print head when the carriage is stopped is positive (P802 > P801 > 0) in both cases. Figure 8E shows a cross-sectional view of the vicinity of the ejection orifices when the internal pressure of the print head reaches P801, and Figure 8F shows a cross-sectional view of the vicinity of the ejection orifices when the internal pressure of the print head reaches P802. Both cross-sections are taken along the XZ plane in Figure 1. As shown in Figures 8E and 8F, when the internal pressure of the print head is positive, the ink meniscus formed at the ejection orifices is convex. If the wiper comes into contact with the ink meniscus in this state, it is possible that the ink meniscus will be destroyed. In other words, if wiping is performed immediately after the carriage stops, there is a high risk of ink leakage from the ejection orifices. Furthermore, because P802 > P801, the meniscus height from the ejection orifice surface is h802 > h801. Therefore, the case of Figure 8C is particularly prone to ink leakage compared to the case of Figure 8A. Subsequently, when the carriage starts to move, there is a possibility that ink may leak and drip from the ejection ports onto the recording medium or the like.

[0059] Therefore, in this embodiment, a wait time is provided with the carriage stopped until the internal pressure of the print head drops from positive to negative, and then the wiping operation is performed. By providing a wait time of at least T802 (seconds) from time T802a to time T802b in FIG. 8D, wiping can be performed when the internal pressure of the print head is negative in both FIG. 8C and FIG. 8A. As shown in FIG. 8G, even if wiping is performed when the internal pressure of the print head is negative, there is little risk of ink leaking. This prevents ink from leaking and dripping from the ejection ports onto the print medium, even if the carriage subsequently moves.

[0060] Also, as shown in FIGS. 8B and 8D, the time until the internal pressure of the recording head becomes negative pressure is different between the case of FIG. 8A and the case of FIG. 8C (T801 < T802). Therefore, by optimizing the wait time in the case of FIG. 8A and introducing control to make it shorter than the wait time in the case of FIG. 8C, a decrease in throughput can be suppressed.

[0061] Furthermore, this wait time can also be optimized according to the scan width and the recording driving density (hereinafter also referred to as "duty"). Note that the recording driving density refers to, in this embodiment, the application ratio (%) of ink dots to a predetermined area during the movement operation of the carriage, and applying 1 ink dot to an area of 1 / 1200 inches square (1200 dpi square) is defined as 100% duty.

[0062] During the constant-speed movement of the carriage, the internal pressure of the recording head converges to the reference pressure P0. The reference pressure P0 mentioned here is the pressure (-80 (mmag)) inside the recording head 101 when the carriage is stationary. When the internal pressure of the recording head during the period D shown in FIG. 6(b) is higher than the reference pressure P0, the longer the scan width immediately before the wiping operation and the longer the time of the period E of the constant-speed movement of the carriage, the closer the internal pressure of the recording head drops to the reference pressure P0.

[0063] On the other hand, the shorter the scan width immediately before the wiping operation and the shorter the period E of the low-speed movement of the carriage, the smaller the decrease in the internal pressure of the recording head and it does not converge to the reference pressure P0. Therefore, the carriage starts to decelerate during the period F while the internal pressure of the recording head has not dropped sufficiently, and the internal pressure of the recording head after the carriage stops becomes high. Therefore, in this embodiment, control is performed such that the shorter the scan width immediately before the wiping operation, the longer the wait time until the wiping operation.

[0064] Furthermore, a high duty cycle during printing means that a larger amount of ink is ejected from the print head. In other words, in addition to the ink being returned from the print head to the tank through the supply tube while the carriage is moving at a constant speed, the ink inside the print head is also reduced by ejection. Therefore, the pressure inside the print head is more likely to decrease as the duty cycle increases. Therefore, in this embodiment, when the carriage is stopped for a wiping operation, the wait time before the wiping operation is controlled to be shorter the higher the duty cycle during scanning.

[0065] In this embodiment, the wait time is determined based on all factors: carriage deceleration, scan width, and print amount. Fig. 9A is a flowchart showing the operation of the recording device from the start to the end of recording. Fig. 9B is a table showing the wait time according to carriage deceleration, scan width, and duty.

[0066] In step S901, the carriage deceleration a, scan width w, and print density (duty) d for the print mode are acquired at the start of printing. In step S902, the wait time Tw for the stop before wiping is determined from these values based on the table in Figure 9B.

[0067] In this embodiment, for example, the carriage deceleration is 400 (inches / second 2 ) or more, the scan width is 36 inches, and the duty is 50%, the wait time is 2.9 seconds.

[0068] After printing is started in step S903, the carriage is accelerated in step S904.

[0069] In step S905, it is determined whether wiping should be performed after scanning is completed. Specifically, the number of dots ejected from the print head during printing is counted as a dot count value, and if this count value exceeds a predetermined value, it is determined that wiping should be performed. Alternatively, the time since the previous wiping is performed is counted as a timer count value, and if this count value exceeds a predetermined value, it is determined that wiping should be performed. The dot count value or timer count value is cleared (set to 0) after wiping is performed. If it is determined that wiping should be performed using the above determination method, the carriage is stopped in step S906, and then the wait time Tw is awaited in step S908, and wiping is performed in step S909.

[0070] On the other hand, if it is determined in step S905 that wiping will not be performed after the scan is completed, the carriage is stopped at deceleration a in step S907.

[0071] In step S910, it is determined whether or not to end the recording. If not, the process returns to step S904; if to end the recording, the operation of this flow ends.

[0072] As described above, in this embodiment, a wait time is set while the carriage is stopped until the internal pressure of the print head drops from positive to negative, depending on the deceleration at which the carriage is stopped, the scan width, and the print density, and then wiping is performed. This makes it possible to prevent ink from leaking and dripping from the ejection ports onto the print medium, even if the carriage starts moving again after wiping.

[0073] Although a specific time has been shown for the wait time, it is not limited to the above numerical value as long as it is equal to or longer than the time it takes for the internal pressure of the print head to decrease from positive pressure to negative pressure.

[0074] Furthermore, although it was determined in step S905 whether wiping should be performed, the number of carriage scans before wiping may be preset, such as every time the carriage moves to the home position or every few times.

[0075] Also, if the carriage deceleration is less than a predetermined value (for example, 100 (inches / second) 2 If the internal pressure of the print head does not become positive immediately after the carriage stops because the waiting time is less than 0 seconds, the waiting time may be set to 0 seconds.

[0076] In this embodiment, as shown in FIG. 9B, the carriage deceleration, scan width, and duty are each divided into two stages to determine the wait time, but each may be divided into multiple stages.

[0077] Furthermore, in this embodiment, the wait time is determined by referring to all three elements of the carriage deceleration, the scan width, and the duty, but it is sufficient to determine the wait time from at least one element.

[0078] The carriage deceleration here may refer to a signal for controlling the carriage speed, or may refer to the results of real-time measurements using an acceleration sensor or the like.

[0079] (Second embodiment) A second embodiment will be described below, which describes a method for controlling the carriage deceleration when the carriage is stopped during a wiping operation.

[0080] FIG. 10(a) shows the carriage velocity profile from when the carriage starts to decelerate and stops on the recovery unit 107 until the internal pressure of the print head becomes zero, and FIG. 10(b) shows the internal pressure profile of the print head at that time. In FIG. 10(a), the horizontal axis represents time and the vertical axis represents carriage velocity. The velocity when moving in the positive direction of the X axis in FIG. 1 is considered positive. In FIG. 10(b), the horizontal axis represents time and the vertical axis represents internal pressure of the print head.

[0081] Here, the carriage speed profile of data 1001 in FIG. 10 (carriage deceleration is 500 (inch / sec) 2 )) will be described.

[0082] 11 is a vector diagram showing the carriage scanning during printing on print medium P. Scans 1, 3, and 5 are scans without wiping operations before or after the scan. We will explain the case where a wiping operation is performed at the end of scan 7, and then scan 9 begins.

[0083] To transition to wiping operation, the carriage must be moved above the recovery unit, so scans 7 and 9 have a longer carriage movement distance than scans 1, 3, and 5. If the deceleration rate for scan 7 were the same as that in Figure 10(a), the internal pressure of the print head would be positive (P1001>0) when the carriage stopped, as shown by data 1001 in Figure 10(b). Therefore, if the wiping operation is transitioned to immediately after the carriage stops, ink may leak and drip.

[0084] Therefore, in this embodiment, when the carriage deceleration is such that the internal pressure of the print head becomes positive after the carriage stops, the carriage deceleration when performing the wiping operation is switched to a value smaller than the carriage deceleration when the wiping operation is not performed. In addition, as described in the first embodiment, the shorter the scan width or the lower the duty, the higher the internal pressure of the print head when the carriage stops. Therefore, in this embodiment, the carriage deceleration after switching is controlled to be smaller the shorter the scan width or the lower the duty during the printing operation.

[0085] Whether or not to switch the carriage deceleration that stops the carriage when performing the wiping operation is determined based on whether or not the carriage deceleration exceeds a predetermined carriage deceleration, which is a carriage deceleration that prevents the internal pressure of the print head from becoming positive when the carriage is stopped.

[0086] FIG. 12(a) shows the carriage velocity profile from when the carriage starts to decelerate at the above-mentioned predetermined deceleration until it stops on the recovery unit, and FIG. 12(b) shows the internal pressure profile of the print head at that time. In FIG. 12(a), the horizontal axis represents time and the vertical axis represents carriage velocity. The velocity when moving in the positive direction of the X-axis in FIG. 1 is considered positive. In FIG. 12(b), the horizontal axis represents time and the vertical axis represents the internal pressure of the print head. It is desirable that the deceleration of scan 7 in FIG. 11 be the same as the deceleration in FIG. 12(a).

[0087] Data 1101 in FIG. 12(a) indicates that the carriage deceleration is smaller than data 1001 (for example, 100 (inches / second)). 2 In this case, the internal pressure of the print head after the carriage stops will not be positive (P1101<0) as shown by data 1101 in FIG. 12(b). Therefore, it is possible to perform the wiping operation immediately after the carriage stops.

[0088] FIG. 13A is a flowchart showing the operation of the printing apparatus from the start to the end of printing, and FIG. 13B is a table showing the carriage deceleration, scan width, and deceleration immediately before wiping according to duty.

[0089] In FIG. 13A, in step S1201, the carriage deceleration a, scan width w, and print density (duty) d for the print mode are acquired at the start of printing. In step S1202, the carriage deceleration aw immediately before wiping is determined from these values based on the table in FIG. 13B. In this embodiment, for example, if the carriage deceleration a is 100 (inches / second), 2 ) or more, the scan width is 36 (inch), and the duty is 50 (%), the carriage deceleration aw is 100 (inch / sec 2 )

[0090] After printing is started in step S1203, the carriage is accelerated in step S1204.

[0091] In step S1205, it is determined whether or not wiping is to be performed after scanning is completed. Whether wiping is necessary is determined in the same manner as in the first embodiment. If it is determined that wiping is to be performed, in step S1206, the carriage is stopped at carriage deceleration aw, and then wiping is performed in step S1208.

[0092] On the other hand, if it is determined in step S1205 that wiping will not be performed after the scan is completed, the carriage is stopped at deceleration a in step S1207.

[0093] In step S1209, it is determined whether or not to end the recording. If not, the process returns to step S1204; if to end, the operation of this flow ends.

[0094] As described above, in this embodiment, when the carriage deceleration during normal printing is such that the internal pressure of the print head becomes positive after the carriage stops, the following is done. That is, the carriage deceleration when a wiping operation is performed is switched to a value smaller than the carriage deceleration when a wiping operation is not performed. This makes it possible to prevent ink from leaking and dripping from the ejection ports onto the print medium, even when the carriage starts moving again after wiping is performed.

[0095] Although specific carriage decelerations have been shown for the carriage deceleration when performing the wiping operation, the carriage deceleration is not limited to the above numerical values as long as the internal pressure of the head does not become positive after the carriage stops.

[0096] Furthermore, in this embodiment, the carriage speed is assumed to be constant, but the carriage speed during scanning when the carriage is stopped for the wiping operation may also be switched.

[0097] In addition, in this embodiment, the carriage speed profile is switched for a scan that stops the carriage for a wiping operation. However, the carriage speed profile may be switched for multiple scans that include a scan that stops the carriage for a wiping operation.

[0098] Furthermore, in this embodiment, the carriage deceleration immediately before wiping is determined by referring to all three elements of carriage deceleration, scan width, and duty, but it is sufficient to determine the carriage deceleration aw from at least one element.

[0099] In this embodiment, the carriage deceleration just before wiping is determined by dividing each of the carriage deceleration, scan width, and duty into two stages, but each may be divided into multiple stages.

[0100] In this embodiment, the case where the wiping operation is started during printing has been described, but the same applies to the case where the wiping operation is started after the carriage movement other than printing has finished.

[0101] (Third embodiment) A third embodiment will be described below, in which a wiping operation is performed continuously after the carriage has stopped, and then a control for setting a carriage stop time is described.

[0102] The time when the carriage, which was moving at speed V803, decelerates at deceleration a803 and stops on the recovery unit is defined as T803. The time from when wiping begins to when wiping ends is defined as T803y, and the time from when wiping ends (T803a) to when the internal pressure of the print head becomes 0 (T803b) is defined as T803c. The carriage speed profile in this case is shown in Figure 14A. The internal pressure profile of the print head at this time is also shown in Figure 14B.

[0103] Also, T804 is the time when the carriage, which was moving at speed V804, decelerates at deceleration a804 (a804 > a803) and stops on the recovery unit. T804y is the time from when wiping begins to when wiping ends, and T804c is the time from when wiping ends (T804a) to when the internal pressure of the print head becomes 0 (T804b). The carriage speed profile in this case is shown in FIG. 14C. The internal pressure profile of the print head at this time is shown in FIG. 14D. In FIGS. 14A and 14C, the horizontal axis represents time, and the vertical axis represents carriage speed. The velocity when moving in the positive direction of the X-axis in FIG. 1 is considered positive. In FIGS. 14B and 14D, the horizontal axis represents time, and the vertical axis represents the internal pressure of the print head.

[0104] As shown in Figures 14B and 14D, the internal pressure of the print head when the carriage is stopped is positive (P804 > P803 > 0) in both cases. Figure 8E shows a cross-sectional view of the vicinity of the ejection orifices when the internal pressure of the print head reaches P803, and Figure 8F shows a cross-sectional view of the vicinity of the ejection orifices when the internal pressure of the print head reaches P804. Both cross-sections are taken along the XZ plane in Figure 1. As shown in Figures 8E and 8F, when the internal pressure of the print head is positive, the ink meniscus formed at the ejection orifice is convex. If the wiper comes into contact with the ink meniscus in this state, it is possible that the ink meniscus will be destroyed. In other words, if the carriage starts moving immediately after wiping is performed, there is a high possibility that ink will leak from the ejection orifice and drip onto the print medium.

[0105] Therefore, in the present embodiment, after wiping is performed after the carriage stops, a waiting time in the carriage stop state is provided until the internal pressure of the recording head decreases from a positive pressure to a negative pressure. FIG. 8H is a cross-sectional view near the discharge port after wiping is performed. As shown in FIG. 8H, when wiping is performed while the internal pressure of the recording head is positive, the meniscus of the ink formed at the discharge port may break. However, if a waiting time is provided without immediately starting the movement of the carriage, the internal pressure of the recording head tends to converge to a negative pressure state. During that time, a force due to capillary action (indicated by the arrow in FIG. 8H) that tries to return the ink that has leaked from the discharge port due to the breakage of the ink meniscus to the discharge port acts, and a meniscus as shown in FIG. 8G can be formed again. If a waiting time of T804c (seconds) or more from T804a to T804b in FIG. 14D is provided after wiping, both data 803 and 804 can converge the internal pressure of the recording head to a negative pressure state. As a result, since the movement of the carriage is started when the internal pressure of the recording head is negative, it is possible to suppress ink from leaking or falling from the discharge port onto the recording medium or the like.

[0106] Also, as shown in FIGS. 14B and 14D, the time until the internal pressure of the recording head becomes negative is different for data 803 and data 804 (T803c < T804c). Therefore, by introducing control to optimize the waiting time of data 803 and make it shorter than the waiting time of data 804, a decrease in throughput can be suppressed.

[0107] Furthermore, this waiting time can be optimized according to the scan width and the recording writing density. FIG. 15A shows a flowchart of the operation from the start to the end of recording, and FIG. 15B shows a table of the waiting time according to the carriage deceleration speed, the scan width, and the duty.

[0108] 15A, in step S1401, the carriage deceleration a, scan width w, and print density (duty) d for that print mode are acquired at the start of printing. In step S1402, the wait time Tw before the carriage moves after wiping is determined from these values based on the table in FIG.

[0109] In this embodiment, for example, the carriage deceleration is 400 (inches / second 2 ) or more, the scan width is 36 inches, and the duty is 50%, the wait time is 2.9 seconds.

[0110] After printing is started in step S1403, the carriage is accelerated in step S1404.

[0111] In step S1405, it is determined whether wiping should be performed after scanning is completed. Specifically, the number of dots ejected from the print head during printing is counted as a dot count value, and if this count value exceeds a predetermined value, it is determined that wiping should be performed. Alternatively, the time since the previous wiping is counted as a timer count value, and if this count value exceeds a predetermined value, it is determined that wiping should be performed. The dot count value or timer count value is cleared (set to 0) after wiping is performed. If it is determined that wiping should be performed using the above determination method, the carriage is stopped in step S1406, and then wiping is performed in step S1408, and carriage movement is stopped for a wait time Tw in step S1409.

[0112] On the other hand, if it is determined in step S1405 that wiping will not be performed after the scan is completed, the carriage is stopped at deceleration a in step S1407.

[0113] In step S1410, it is determined whether or not to end the recording. If not, the process returns to step S1404; if to end, the operation of this flow ends.

[0114] As described above, in this embodiment, a wait time is set in which the carriage is stopped after wiping is performed, depending on the deceleration rate at which the carriage is stopped, until the internal pressure of the print head drops from positive to negative. This makes it possible to prevent ink from leaking or dripping from the ejection ports onto the print medium, even if the carriage starts moving again after wiping. Note that although a specific wait time is shown, it is not limited to the above numerical value, as long as it is equal to or longer than the time it takes for the internal pressure of the print head to drop from positive to negative.

[0115] Also, although it was determined in step S1405 whether wiping should be performed, the number of carriage scans before wiping may be preset, such as every time the carriage moves to the home position or every few times.

[0116] (Fourth embodiment) A fourth embodiment will be described below, which describes control for setting a carriage stop time after a wiping operation is performed at a low speed immediately before the carriage stops.

[0117] The carriage, which was moving at speed V805, decelerates at deceleration a805 and is at a low speed just before stopping on the recovery unit. The time when wiping starts is T805y, and the time from when wiping ends to when the internal pressure of the print head becomes 0 is T805c. The carriage speed profile in this case is shown in Figure 16A. The internal pressure profile of the print head at this time is shown in Figure 16B.

[0118] Furthermore, the time when wiping begins is T806, when the carriage, moving at speed V806, decelerates at deceleration a806 (a806 > a805) and stops on the recovery unit. The time from when wiping begins to when it ends is T806y, and the time from when wiping ends (T806a) to when the internal pressure of the print head becomes zero (T806b) is T806c. The carriage speed profile in this case is shown in Figure 16C. The internal pressure profile of the print head at this time is also shown in Figure 16D. In Figures 16A and 16C, the horizontal axis represents time, and the vertical axis represents carriage speed. The speed when moving in the positive direction of the X-axis in Figure 1 is considered positive. In Figures 16B and 16D, the horizontal axis represents time, and the vertical axis represents the internal pressure of the print head.

[0119] 16B and 16D, the internal pressure of the print head when the carriage is moving at low speed just before it stops is positive (P806>P805>0). As with the third embodiment described above, if the wiper comes into contact with the nozzle face in this state, the ink meniscus may be destroyed. In other words, if the carriage starts moving immediately after wiping, ink may leak and drip from the nozzles onto the print medium.

[0120] Therefore, in this embodiment, after wiping at a low speed immediately before the carriage stops, a waiting time is provided in the stopped state of the carriage until the internal pressure of the recording head decreases from a positive pressure to a negative pressure. Similar to the third embodiment, a cross-sectional view near the discharge port after wiping is shown in FIG. 8H. As shown in FIG. 8H, when wiping is performed in a state where the internal pressure of the recording head is positive, the ink meniscus formed at the discharge port may break. However, if a waiting time is provided without immediately starting the movement of the carriage, the internal pressure of the recording head tends to converge to a negative pressure state. During that time, a capillary force (indicated by an arrow in FIG. 8H) that tries to return the ink leaking from the discharge port due to the breakage of the ink meniscus acts on the ink, and a meniscus as shown in FIG. 8G can be formed again. If a waiting time of T806c (seconds) or more from time T806a to time T806b in FIG. 16D is provided after wiping, both data 805 and 806 can converge the internal pressure of the recording head to a negative pressure state. As a result, since the movement of the carriage is started when the internal pressure of the recording head is negative, it is possible to suppress ink from leaking or falling from the discharge port onto the recording medium or the like.

[0121] Also, as shown in FIGS. 16B and 16D, the time until the internal pressure of the recording head becomes negative is different for data 805 and data 806 (T805c < T806c). Therefore, by optimizing the waiting time of data 805 and introducing control to make it shorter than the waiting time of data 806, a decrease in throughput can be suppressed.

[0122] Furthermore, similar to the first and third embodiments, this waiting time can also be optimized according to the scan width and the recording write density.

[0123] As described above, in this embodiment, a wait time is provided during the carriage stop state until the internal pressure of the print head drops from positive to negative pressure after wiping is performed at a low speed just before the carriage stops, depending on the deceleration rate at which the carriage stops. This prevents ink from leaking or dripping from the ejection ports onto the print medium, even if the carriage starts moving again after wiping. Furthermore, because wiping is performed before the carriage stops, the time required for the carriage to start decelerating and then accelerate again after wiping is shorter than in the previous embodiment, improving throughput. Therefore, this is particularly preferable when wiping is performed frequently, such as every time the carriage moves to the home position or every few times.

[0124] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more of the functions.

[0125] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0126] 101: recording head, 102: supply tube, 103: ink tank, 104: carriage, 107: recovery unit, 108: ink supply system, 407: subtank, 301: wiper, 309: wiping unit

Claims

1. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement of the carriage and the wiping operation of the wiping means so that, when the deceleration when the carriage is stopped is a first deceleration, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a first time, and, when the deceleration when the carriage is stopped is a second deceleration smaller than the first deceleration, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a second time shorter than the first time; A recording device comprising:

2. 2. The recording apparatus according to claim 1, wherein the first deceleration rate and the second deceleration rate are deceleration rates at which the internal pressure of the recording head becomes positive when the carriage stops.

3. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement of the carriage and the wiping operation of the wiping means so that, when the distance traveled by the carriage at a constant speed before the carriage is stopped is a first distance, a first time is the time from when the carriage stops to when the wiping means starts wiping the ejection port surface, and, when the distance traveled by the carriage at the constant speed is a second distance longer than the first distance, a second time is the time from when the carriage stops to when the wiping means starts wiping the ejection port surface; A recording device comprising:

4. 4. The recording apparatus according to claim 3, wherein the internal pressure of the recording head is a positive pressure when the carriage stops.

5. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement of the carriage and the wiping operation of the wiping means so that, when a recording impact density indicating the rate at which ink dots are applied to a predetermined area of the recording medium during movement of the carriage before the carriage is stopped is a first impact density, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a first time, and, when the recording impact density is a second impact density higher than the first impact density, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a second time shorter than the first time; A recording device comprising:

6. 5. The recording apparatus according to claim 4, wherein the internal pressure of the recording head is a positive pressure when the carriage stops.

7. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement operation of the carriage and the wiping operation of the wiping means so that, when the deceleration when stopping the carriage is a first deceleration, a time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage starts is a first time, and, when the deceleration when stopping the carriage is a second deceleration smaller than the first deceleration, a time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage starts is a second time shorter than the first time; A recording device comprising:

8. 8. The recording apparatus according to claim 7, wherein wiping of the ejection port surface by the wiping means is started after the carriage has stopped.

9. 8. The recording apparatus according to claim 7, wherein wiping of the ejection port surface by the wiping means is started before the carriage stops.

10. 10. The recording apparatus according to claim 7, wherein the first deceleration rate and the second deceleration rate are deceleration rates at which the internal pressure of the recording head becomes positive when the carriage stops.

11. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement operation of the carriage and the wiping operation of the wiping means so that, when the distance traveled by the carriage at a constant speed before the carriage is stopped is a first distance, a time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage starts is a first time, and, when the distance traveled by the carriage at the constant speed is a second distance longer than the first distance, a time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage starts is a second time shorter than the first time; A recording device comprising:

12. 12. The recording apparatus according to claim 11, wherein wiping of the ejection port surface by the wiping means is started after the carriage has stopped.

13. 12. The recording apparatus according to claim 11, wherein wiping of the ejection port surface by the wiping means is started before the carriage stops.

14. 14. The recording apparatus according to claim 11, wherein the internal pressure of the recording head is a positive pressure when the carriage stops.

15. a carriage that is equipped with a recording head that ejects ink and moves back and forth relative to the recording medium; a wiping means for wiping an ejection port surface of the recording head on which ink ejection ports are formed; a control means for controlling the movement operation of the carriage and the wiping operation of the wiping means so that, when a recording impact density indicating the rate at which ink dots are applied to a predetermined area of the recording medium during movement of the carriage before the carriage is stopped is a first impact density, a first time is the time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage begins, and, when the recording impact density is a second impact density higher than the first impact density, a second time is the time from when the wiping means finishes wiping the ejection port surface to when the next movement operation of the carriage begins, which is shorter than the first time; A recording device comprising:

16. 16. The recording apparatus according to claim 15, wherein wiping of the ejection port surface by the wiping means is started after the carriage has stopped.

17. 16. The recording apparatus according to claim 15, wherein wiping of the ejection port surface by the wiping means is started before the carriage stops.

18. 18. The recording apparatus according to claim 15, wherein the internal pressure of the recording head is a positive pressure when the carriage stops.

19. 19. A recording apparatus according to claim 1, wherein the internal pressure of the recording head when the carriage is stopped so that the wiping means can wipe the ejection port surface is higher than the internal pressure of the recording head when the carriage is stationary.

20. 20. The recording apparatus according to claim 1, further comprising an ink tank for storing ink, wherein ink is supplied from the ink tank to the recording head by a water head difference.

21. 19. The recording apparatus according to claim 1, wherein the wiping means has a wiping member made of a sheet-like porous material.

22. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, comprising a control step of controlling the movement operation of the carriage and the wiping operation of the wiping means so that, when the deceleration when stopping the carriage is a first deceleration, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a first time, and, when the deceleration when stopping the carriage is a second deceleration smaller than the first deceleration, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a second time shorter than the first time.

23. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, comprising a control step of controlling the movement operation of the carriage and the wiping operation of the wiping means so that, when the distance traveled by the carriage at a constant speed before the carriage is stopped is a first distance, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a first time, and, when the distance traveled by the carriage at a constant speed is a second distance longer than the first distance, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a second time shorter than the first time.

24. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, characterized by having a control process for controlling the carriage movement operation and the wiping operation of the wiping means so that, when a recording impact density indicating the rate of ink dot application to a specified area of the recording medium during the carriage movement operation before the carriage is stopped is a first impact density, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a first time, and when the recording impact density is a second impact density higher than the first impact density, the time from when the carriage stops to when the wiping means starts wiping the ejection port surface is a second time shorter than the first time.

25. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, comprising a control step of controlling the carriage movement operation and the wiping operation of the wiping means so that, when the deceleration when stopping the carriage is a first deceleration, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation starts is a first time, and when the deceleration when stopping the carriage is a second deceleration that is smaller than the first deceleration, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation starts is a second time that is shorter than the first time.

26. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, comprising a control step of controlling the carriage movement operation and the wiping operation of the wiping means so that, when the distance traveled by the carriage at a constant speed before the carriage is stopped is a first distance, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation begins is a first time, and, when the distance traveled by the carriage at a constant speed is a second distance longer than the first distance, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation begins is a second time shorter than the first time.

27. A method for controlling a recording apparatus including a carriage that is mounted with a recording head that ejects ink and that moves back and forth relative to a recording medium, and a wiping unit that wipes an ejection port surface of the recording head on which ink ejection ports are formed, comprising: A control method for a recording device, characterized by having a control process for controlling the carriage movement operation and the wiping operation of the wiping means so that, when a recording impact density indicating the rate of ink dot application to a specified area of the recording medium during the carriage movement operation before the carriage is stopped is a first impact density, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation starts is a first time, and when the recording impact density is a second impact density higher than the first impact density, the time from when the wiping means finishes wiping the ejection port surface to when the next carriage movement operation starts is a second time shorter than the first time.

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