Inkjet recording apparatus and recording method

Abstract

To adjust accurately a recording position.SOLUTION: An ink jet recording device includes: setting means capable of setting either of a first speed starting-up control of controlling starting-up to a first reaching speed as a recording scan speed in performing recording, and a second speed starting-up control as a starting-up control of a speed faster than that of the first speed starting-up control; acquisition means for acquiring a correction value corresponding to the starting-up control set by the setting means in a first correction value corresponding to the first speed starting-up control and a second speed correction value corresponding to the second speed starting-up control; and correction means for correcting an ejection timing of ink, on the basis of the correction value acquired by the acquisition means.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a technique for adjusting a printing position printed by a print head of an inkjet printing apparatus. [Background technology]

[0002] There are recording devices that perform recording by forming dots on a recording medium such as paper. Some recording devices use a recording head that is mounted on a carriage and moves in a predetermined direction relative to the recording medium, and has ink ejection ports arranged as recording elements in a different direction from the predetermined direction (for example, the conveyance direction of the recording medium). In a recording device that uses such a recording head, a process is required to determine the appropriate ejection timing (hereinafter also referred to as registration adjustment) in order to align the landing positions of ink droplets ejected from each ejection port array.

[0003] Patent Document 1 describes a registration adjustment technique for matching the landing positions of ink droplets in forward and backward recording in bidirectional recording, in which recording is performed while a recording head is scanned back and forth. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-241148 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the start-up control of the carriage scanning speed is different, the amount of fluctuation in the carriage attitude may change, which may cause deviation in the landing position.

[0006] An object of the present invention is to provide a technique for adjusting the printing position with high precision. [Means for solving the problem]

[0007] An inkjet recording apparatus according to one aspect of the present invention has a recording head equipped with a nozzle array in which nozzles for ejecting ink are arranged, and performs bidirectional recording on a recording medium by scanning the recording head back and forth in a direction different from the arrangement direction of the nozzles, and is equipped with: a setting means for setting either a first speed start-up control that controls a start-up up to a first reachable speed that is a recording scanning speed when recording, or a second speed start-up control that is a start-up control at a speed faster than the first speed start-up control; an acquisition means for acquiring a correction value corresponding to the start-up control set by the setting means out of a first correction value corresponding to the first speed start-up control that corrects a deviation in landing position due to the nozzle array, and a second correction value corresponding to the second speed start-up control that corrects a deviation in landing position due to the nozzle array; and a correction means for correcting an ink ejection timing based on the correction value acquired by the acquisition means. The inkjet recording apparatus is capable of recording at a second reaching speed which is a second recording scanning speed different from the recording scanning speed, the setting means is capable of setting either the first speed start-up control or the second speed start-up control as the start-up control up to the second reaching speed, and further comprises a determination means for determining a fifth correction value corresponding to the second speed start-up control for controlling the start-up up to the second reaching speed based on the first correction value, the second correction value, and a fourth correction value corresponding to the first speed start-up control for controlling the start-up up to the second reaching speed, and the acquisition means acquires the fifth correction value determined by the determination means when the second speed start-up control is set by the setting means as the start-up up to the second reaching speed. It is characterized by the above. Effect of the Invention

[0008] According to the present invention, the recording position can be adjusted with high precision. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of the external configuration of a recording apparatus. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of an optical sensor. [Diagram 3] FIG. 2 is a diagram showing an arrangement of ejection nozzles of a recording head. [Figure 4] FIG. 2 is a diagram illustrating a functional configuration of a recording apparatus. [Diagram 5] 10A and 10B are diagrams illustrating an example of the configuration of a registration adjustment pattern. [Figure 6] FIG. 4 is a diagram illustrating an example of a registration adjustment pattern. [Figure 7] FIG. 13 is a diagram showing the measurement results of optical reflectance. [Figure 8] FIG. 4 is a diagram showing the scanning distance and recording scanning speed for borderless printing and bordered printing. [Figure 9] 5A and 5B are diagrams illustrating changes in the position of a carriage. [Figure 10] 11A and 11B are diagrams illustrating deviations in landing positions on a recording medium. [Figure 11] 10 is a flowchart showing a process for determining a registration adjustment value. [Figure 12] 13 is a diagram showing an example of a storage area for registration adjustment values ​​for bidirectional printing; FIG. [Figure 13] 11A and 11B are diagrams illustrating an example of calculating a registration adjustment value. [Figure 14] 11A and 11B are diagrams illustrating an example of calculating a registration adjustment value. [Figure 15] 11A and 11B are diagrams for explaining landing deviation caused by changes in the carriage posture. [Figure 16] 11A and 11B are diagrams for explaining landing deviation in one-way printing. [Figure 17] 10 is a flowchart showing a process for determining a registration adjustment value. [Figure 18] 11 is a diagram illustrating an example of a storage area for registration adjustment values. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An example of an embodiment will be described in detail below with reference to the accompanying drawings. Note that the following embodiment does not limit the present invention, and not all of the combinations of features described in the embodiment are necessarily essential to the solution of the present invention. In addition, the relative positions and shapes of the components described in the embodiment are merely examples, and are not intended to limit the scope of the present invention to only those.

[0011] <<First embodiment>> <Recording device configuration> 1 is an external perspective view showing an outline of the configuration of an inkjet printing apparatus according to this embodiment. The printing apparatus 100 includes a carriage 102 mounted with a print head 103 that performs printing by ejecting ink according to the inkjet method. The printing apparatus 100 transmits a driving force generated by a carriage motor M1 to the carriage 102 via a transmission mechanism 104, and moves the carriage 102 back and forth in the direction of arrow A. The printing apparatus 100 feeds a printing medium P such as a recording paper via a paper feed mechanism 105 and transports it to a printing position. The printing apparatus 100 moves the carriage 102 back and forth in a scanning direction (direction of arrow A) that intersects with the transport direction of the printing medium P, and performs printing by ejecting ink from the print head 103 onto the printing medium P at the printing position.

[0012] Furthermore, in order to maintain the print head 103 in good condition, the printing device 100 moves the carriage 102 to the position of a recovery device 110 and intermittently performs an ejection recovery process for the print head 103. In addition to the print head 103, an ink cartridge 106 that stores ink to be supplied to the print head 103 is attached to the carriage 102 of the printing device 100. The ink cartridge 106 is configured to be freely attached to and detached from the carriage 102.

[0013] The recording device 100 shown in Fig. 1 is configured to be capable of color recording. Specifically, the carriage 102 is equipped with four ink cartridges that respectively contain magenta (M), cyan (C), yellow (Y), and black (K) ink. Each of these four ink cartridges can be attached and detached independently.

[0014] The carriage 102 and the print head 103 are configured so that the joint surfaces of both members are in proper contact with each other to achieve and maintain the required electrical connection. The print head 103 selectively ejects ink from a plurality of ejection ports by applying energy in response to a print signal. The print head 103 employs an inkjet method that ejects ink using thermal energy, and is provided with an electrothermal converter to generate thermal energy, which ejects ink from the ejection ports. The electrothermal converter is provided corresponding to each of the ejection ports, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal converter in response to a print signal. Note that the print head is not limited to one that uses an electrothermal converter, and an inkjet print head that uses a piezoelectric element or an electrostatic element may also be used.

[0015] 1, the carriage 102 is connected to a part of a drive belt 107 of a transmission mechanism 104 that transmits the driving force of a carriage motor M1, and is configured to be guided and supported so as to be slidable in the direction of arrow A along a guide shaft 113. That is, the carriage 102 reciprocates along the guide shaft 113 by the forward and reverse rotation of the carriage motor M1. Also, a scale 108 (CR encoder film) for indicating the absolute position of the carriage 102 is provided along the moving direction of the carriage 102 (the direction of arrow A). In this embodiment, a transparent PET film with black bars printed at a required pitch is used as the scale 108, one end of which is fixed to a chassis 109, and the other end is supported by a leaf spring (not shown).

[0016] The recording device 100 is also provided with a platen (not shown) facing the ejection port surface on which the ejection ports (not shown) of the recording head 103 are formed. When the carriage 102 carrying the recording head 103 moves back and forth by the driving force of the carriage motor M1, a recording signal is given to the recording head 103 to eject ink, thereby performing printing over the entire width of the recording medium P conveyed onto the platen. Also, an ejection recovery process is performed by ejecting ink onto the platen (hereinafter referred to as preliminary ejection) to prevent ejection failures due to drying of ink at the ejection ports of the recording head 103. The preliminary ejection is performed onto the platen outside the paper.

[0017] The print head 103 is supported by a carriage 102, which is connected to a motor (not shown) by a belt and is configured to be capable of reciprocating motion. The standby position of the print head 103 is also called a home position. The position corresponding to the opposite side of the print medium P is also called a back position. The position of the carriage 102 is managed by a linear scale arranged along the carriage scanning direction. The position of the carriage 102 is managed by optically reading the linear scale with an encoder sensor (not shown) provided on the carriage 102. The speed of the carriage 102 is managed by measuring the passing time of the scale 108. In addition, the speed is increased by setting each target speed at the position of the carriage 102, and is made to reach a certain speed. The timing of ink ejection from the print head 103 (hereinafter also simply referred to as ejection timing) is also determined based on the read pulse output from the encoder sensor. It is possible to adjust the landing position on the print medium P by delaying or advancing the ejection timing during carriage scanning using a parameter that controls the ejection timing.

[0018] 1 is driven by a conveying motor M2 to convey the recording medium P. A pinch roller 115 abuts the recording medium P against the conveying roller 114 by a spring (not shown). A pinch roller holder 116 supports the pinch roller 115 so as to be freely rotatable. A conveying roller gear 117 is fixed to one end of the conveying roller 114. The conveying roller 114 is driven by the rotation of the conveying motor M2 transmitted to the conveying roller gear 117 via an intermediate gear (not shown).

[0019] The discharge roller 120 discharges the recording medium P on which the image has been formed by the recording head 103 to the outside of the inkjet recording device. The discharge roller 120 is configured to be driven by the transmission of the rotation of the conveying motor M2. The discharge roller 120 abuts against a spur roller (not shown) that presses the recording medium P with a spring (not shown). The spur holder 122 rotatably supports the spur roller.

[0020] The recording device 100 is provided with a recovery device 110 for recovering from ejection defects in the recording head 103. As shown in Fig. 1, the recovery device 110 is provided at a position (e.g., a position corresponding to the home position) outside the range of reciprocating motion (outside the recording area) for recording operation of the carriage 102 carrying the recording head 103.

[0021] The recovery device 110 includes a capping mechanism 111 that caps the ejection port surface of the recording head 103, and a wiping mechanism 112 that cleans the ejection port surface of the recording head 103. The recovery device 110 performs an ejection recovery process in which ink is forcibly discharged from the ejection ports by a suction pump or the like in the recovery device in conjunction with the capping of the ejection port surface by the capping mechanism 111. This makes it possible to remove ink with increased viscosity or air bubbles in the ink flow path of the recording head 103.

[0022] Furthermore, when not performing printing, the ejection port surface of the print head 103 is capped by a capping mechanism 111 to protect the print head 103 and suppress evaporation or drying of ink. The wiping mechanism 112 is disposed near the capping mechanism 111 and configured to wipe off ink droplets adhering to the ejection port surface of the print head 103. The capping mechanism 111 and wiping mechanism 112 are configured to enable the ink ejection state of the print head 103 to be kept normal.

[0023] 2 is a diagram showing a schematic configuration of an optical sensor of the recording apparatus 100 of this embodiment. In addition to the recording head 103 and the ink cartridge 106, the carriage 102 is equipped with a reflective optical sensor (hereinafter referred to as the optical sensor) 200. The optical sensor 200 is a sensor capable of acquiring optical characteristics, and optically reads a registration adjustment pattern (described later) recorded on the recording medium P and measures its recording density. Note that the optical sensor 200 in FIG. 2 does not have a configuration for measuring the distance of the recording medium P, but measures the recording density of the registration adjustment pattern.

[0024] 2, the optical sensor 200 includes a light-emitting unit 201 realized by an LED or the like, and a light-receiving unit 202 realized by a photodiode or the like. Irradiation light 210 emitted by the light-emitting unit 201 is reflected on the recording medium P, and the reflected light 220 enters the light-receiving unit 202. The light-receiving unit 202 converts the reflected light 220 into an electrical signal.

[0025] When measuring the recording density of the registration adjustment patterns, conveyance of the recording medium P in the sub-scanning direction and movement of the carriage 102, to which the optical sensor 200 is attached, in the main scanning direction are alternately performed. In this way, the optical sensor 200 detects the density of the registration adjustment patterns recorded on the recording medium P as optical reflectance.

[0026] FIG. 3 is a diagram showing the arrangement of ejection nozzles in the print head of this embodiment. The print head 103 has nozzle rows in which a plurality of nozzles are arranged at predetermined intervals in the sub-scanning direction (Y direction, nozzle arrangement direction). The nozzle rows are arranged with a shift from each other in the sub-scanning direction (Y direction, nozzle arrangement direction) that intersects (orthogonal in this embodiment) the main scanning direction (X direction) in which the nozzle rows are arranged. Specifically, the nozzles (302K, 302C, 302M, 302Y) that eject ink of each color (CMYK) are arranged at predetermined intervals along the sub-scanning direction, and each nozzle row is arranged along the main scanning direction. The nozzle rows are arranged in pairs (302K-A, 302K-B, 302C-A, 302C-B, 302M-A, 302M-B, 302Y-A, 302Y-B) corresponding to each color of ink. In each nozzle row, for example, 640 nozzles are arranged at intervals of 600 dpi (dots per inch). In addition, the nozzle rows (two nozzle rows) ejecting ink of the same color are arranged to be shifted from each other in the sub-scanning direction by, for example, 1200 dpi (half pitch). That is, in order to achieve high printing resolution, the arrangement positions of the nozzle rows are shifted in the sub-scanning direction. In this embodiment, the resolution of each nozzle row in the sub-scanning direction is 600 dpi, but by shifting the arrangement positions of the nozzle rows, printing at a resolution of 1200 dpi in the sub-scanning direction is possible.

[0027] 4 is a diagram showing the functional configuration of the recording device of this embodiment. The controller 60 is configured with an MPU 51, a ROM 52, a ROM 57, an application specific integrated circuit (ASIC) 53, a RAM 54, a system bus 55, an A / D conversion unit 56, and the like. Here, the ROM 52 and ROM 57 store programs corresponding to a control sequence described later, required tables, and other fixed data. The ROM 52 is configured, for example, as an EEPROM (Electrically Erasable Programmable Read-Only Memory), and is configured so that the contents can be rewritten.

[0028] The ASIC 53 controls the carriage motor M1 and the transport motor M2. The ASIC 53 also generates control signals for controlling the print head 103. The RAM 54 is used as an area for loading image data or a working area for executing programs. A system bus 55 interconnects the MPU 51, the ASIC 53, and the RAM 54 for data exchange. The A / D conversion unit 56 A / D converts analog signals input from a sensor group 30 (described later) and supplies the converted digital signals to the MPU 51.

[0029] The MPU 51 performs overall control of the operation of the recording device 100. For example, during registration adjustment processing, the MPU 51 determines a registration adjustment correction value (hereinafter, referred to as the registration adjustment value) based on the measurement result of the above-mentioned registration adjustment pattern. This registration adjustment value is temporarily stored in, for example, the RAM 54, and then stored in the ROM 52. The MPU 51 also adjusts the ejection timing of ink ejected from each nozzle based on the registration adjustment value stored in, for example, the RAM 54, and corrects the landing position (attachment position) of dots formed on the recording medium. The ROM 52 and the like also hold the type of recording medium and information on the thickness of the recording medium that has been previously measured or otherwise specified. The ROM 52 and the like also hold a rough estimate value for a type of recording medium whose thickness information has not been specified.

[0030] The switch group 20 includes a power switch 21, a print switch 22, and a recovery switch 23. The sensor group 30 is a sensor group for detecting the state of the device, and includes a position sensor 31 and a temperature sensor 32. When the print head 103 scans, the ASIC 53 directly accesses the storage area of ​​the RAM 54 and transfers data to the print head 103 for driving the print elements (ejection heaters).

[0031] The printhead control unit 44 controls the printing operation by the printhead 103. The carriage motor M1 is a drive source for causing the carriage 102 to scan back and forth in a predetermined direction, and the carriage motor driver 40 controls the driving of the carriage motor M1. The transport motor M2 is a drive source for transporting the printing medium, and the transport motor driver 42 controls the driving of the transport motor M2.

[0032] The host device 10 is a computer (or an image reader or digital camera, etc.) that serves as a supply source of image data. Image data, commands, status signals, etc. are exchanged between the host device 10 and the recording device 100 via an interface (hereinafter referred to as I / F) 11. The host device 10 has a printer driver, which stores information on the type of recording medium and the thickness of the recording medium that has been previously measured or otherwise specified. The printer driver also stores rough estimates for types of recording media for which thickness information has not been specified. This concludes the explanation of the configuration of the recording device 100.

[0033] <Registration adjustment> The registration adjustment is a process for determining an appropriate ejection timing to match the landing positions of ink droplets ejected from an ejection port array (nozzle array). As a method of the registration adjustment, for example, a reference pattern is recorded on a recording medium by a certain reference nozzle array, and a plurality of patterns with slightly shifted recording positions are recorded on the recording medium by other nozzle arrays. Then, by measuring the density of the recorded patterns, a registration adjustment correction amount (registration adjustment value) for matching the recording positions is determined. In addition, in bidirectional printing, a reference pattern is recorded in forward printing, and a plurality of patterns with shifted recording positions are recorded in backward printing, thereby determining a registration adjustment value for matching the recording positions in the forward and backward directions. Hereinafter, the registration adjustment patterns used in the registration adjustment process will be described with reference to Figs. 5 to 7.

[0034] FIG. 5 is a diagram for explaining an example of the configuration of the registration adjustment pattern when the optical sensor 200 of this embodiment detects the density. The registration adjustment pattern is configured so that a rectangular pattern of i pixels×n pixels is periodically repeated in the main scanning direction for each blank area of ​​m pixels. The shift pattern 502 is printed with its printing position shifted by a predetermined number of pixels a with respect to the reference pattern 501. The resolution and shift amount of these registration adjustment patterns may be determined according to the printing resolution of the printing device. In this embodiment, the printing resolution is assumed to be 1200 dpi. In FIG. 5, the reference pattern and the shift pattern are illustrated shifted in the vertical direction for convenience of explanation, but in reality, the two patterns 501 and 502 are printed overlapping each other. That is, the reference pattern is printed overlapping the shift pattern shifted by a predetermined number of pixels a in the main scanning direction.

[0035] FIG. 6 shows an example in which a plurality of registration adjustment patterns shown in FIG. 5 are printed in the main scanning direction. In this case, the registration adjustment pattern group 610 shown in FIG. 6 is printed while changing the shift amount a of the shift pattern from -3 pixels to +3 pixels. That is, as can be seen from FIG. 6, when the shift amount is 0, the reference pattern and the shift pattern are printed overlapping each other. On the other hand, the larger the shift amount is, the larger the shift between the reference pattern and the shift pattern becomes, so that the width of the pattern becomes wider. For convenience, FIG. 6 shows an example in which the shift amount is 0 and the shift between the reference pattern and the shift pattern is small, but when the registration adjustment pattern is actually printed, the position where the shift between the reference pattern and the shift pattern is small varies depending on various conditions.

[0036] When the amount of deviation in the printing position between the reference pattern and the shift pattern changes, the area ratio of the ink on the printing medium changes as shown in FIG.

[0037] Fig. 7 shows the measurement result 720 of the optical reflectance when each of the registration adjustment patterns shown in Fig. 6 is measured by the optical sensor 200. Note that the density is inversely proportional to the reflectance, and the smaller the position shift between the registration adjustment patterns actually recorded on the recording medium, the lower the density. In other words, the higher the reflectance of the shifted pattern, the less position shift occurs, and the registration adjustment value can be determined when the density of the registration adjustment pattern is the lowest.

[0038] The number of registration adjustment patterns formed on the recording medium and the amount of shifting may be determined according to the adjustment range required by the mechanical tolerance of the device or the shift unit of the recording position. In other words, they may be determined according to the accuracy of the registration adjustment process. The recording area of ​​the registration adjustment patterns may be determined according to the size of the detection area of ​​the optical sensor 200, the width of the area that can be recorded in one recording scan, or the size of the area in which the registration adjustment patterns can be recorded on the recording medium.

[0039] In addition, the nozzle rows used to form the reference pattern and the shift pattern are determined by a combination of the ink color and the scanning direction of the nozzle row to be adjusted. For example, for the registration adjustment of the ink color of the nozzle row, a reference nozzle row (e.g., 302K-A) is determined to form the reference pattern, and the other nozzle row (e.g., 302C-A) forms the shift pattern. In addition, the registration adjustment during bidirectional printing can be performed in the same manner as above. For example, when forming the reference pattern, the nozzle row 302K-A is used to perform forward printing, and when forming the shift pattern, the nozzle row 302K-A is used to perform backward printing. This allows the registration adjustment of bidirectional printing using the same nozzle row 302K-A to be performed with high accuracy. The combination of nozzle rows is not limited to this, and any appropriate combination may be used.

[0040] A registration adjustment value is determined based on the position shift amount a thus determined. The registration adjustment value is a value indicating the amount of correction for the ink ejection timing, and the ink ejection timing of each nozzle row is controlled based on this registration adjustment value.

[0041] <Bidirectional recording registration adjustment> The following describes the registration adjustment for bidirectional printing performed in this embodiment. That is, when focusing on a specific nozzle row (first nozzle row) among multiple nozzle rows, an example of adjusting the printing position in the forward direction and the printing position in the reverse direction using the first nozzle row will be described.

[0042] FIG. 8 is a diagram showing an example of the scanning distance and recording scanning speed of the carriage 102 in borderless printing and bordered printing in this embodiment. The scanning distance of the carriage 102 from the home position or back position to the print start position is shorter in borderless printing than in bordered printing. In addition, when recording is performed in the speed rise section, the carriage scanning speed changes, so the landing position of the ink droplets also changes. For this reason, it is preferable to record only in the constant speed section where the speed rise is completed by the time the print start position is reached and the recording scanning speed of the carriage is stable. Therefore, even if the recording scanning speed of the carriage 102 in the constant speed section is the same, the speed rise section is shorter in borderless printing than in bordered printing. As a result, in borderless printing, it is necessary to increase the rise control of the scanning speed of the carriage 102 compared to bordered printing. In other words, in borderless printing, it is necessary to accelerate faster in the rise section than in bordered printing. FIG. 8 shows such a relationship.

[0043] FIG. 9 is a diagram for explaining the change in the carriage posture. FIG. 9(a) shows a case where the carriage 102 is not accelerating. FIG. 9(b) shows the posture of the carriage 102 in a constant speed section (i.e., a section where printing is performed) in the start-up control a of the scanning speed of forward printing. When the speed of the carriage 102 starts up, the carriage 102 is pulled in the scanning direction by the drive belt 107. That is, as shown in FIG. 9(b), the posture of the carriage 102 changes and tilts in a direction such that it rotates around the guide shaft 113 as a fulcrum. Also, in the constant speed section where the speed start-up is completed and the target speed is reached, the posture of the carriage 102 that occurred in the speed start-up section remains tilted without changing.

[0044] Fig. 9(d) shows a case where the carriage 102 is stopped by the control to decrease the scanning speed of forward printing. When the speed of the carriage 102 decreases, the carriage 102 is pulled in the opposite direction to the scanning direction by the drive belt 107. Therefore, the control to decrease the scanning speed of the carriage 102 eliminates the posture fluctuation of the carriage 102 that occurred due to the control to increase the scanning speed, and the carriage 102 returns to the posture in Fig. 9(a) when it is not accelerating.

[0045] Fig. 9(e) shows the posture of the carriage 102 in a constant speed section during scanning speed start-up control a for backward printing. When the speed of the carriage 102 starts to increase, the scanning direction is opposite to that for forward printing, so the posture of the carriage 102 is tilted in the opposite direction to that for forward printing due to the scanning speed start-up control of the carriage 102. Similarly, when the carriage 102 stops during backward printing, the posture returns to that in Fig. 9(a) when the carriage 102 is not accelerating.

[0046] Fig. 9(c) shows the posture of the carriage 102 in a constant speed section in scanning speed start-up control b for forward printing. Note that scanning speed start-up control b has a greater start-up control than scanning speed start-up control a. In other words, scanning speed start-up control b has a greater acceleration than scanning speed start-up control a. As the start-up control of the scanning speed of the carriage 102 increases, the amount of posture fluctuation of the carriage 102 increases. In other words, the amount of posture fluctuation (amount of rotation) of the carriage 102 is greater in Fig. 9(c) than in Fig. 9(b).

[0047] FIG. 9(f) shows the posture of the carriage 102 in the constant speed section during scanning speed rise control b for backward recording. Similarly, as the rise control of the scanning speed of the carriage 102 increases, the amount of posture fluctuation of the carriage 102 increases. Also in the cases of FIGS. 9(c) and (f), the fall control of the scanning speed of the carriage 102 returns the carriage 102 to its original posture when the carriage 102 is not accelerating as shown in FIG. 9(a). In this way, the posture of the carriage 102 in the constant speed section (i.e., the section where recording is performed) changes depending on the magnitude of the scan speed rise control (magnitude of acceleration) in both forward recording and backward recording.

[0048] Fig. 10 is a diagram for explaining the shift in landing position on the printing medium P due to the start-up control of the scanning speed of the carriage 102 in bidirectional printing with the same arrival speed (printing scanning speed). As shown in Fig. 10, when the carriage 102 performs registration adjustment with the scanning speed start-up control a, the carriage 102 is adjusted with high precision with the scanning speed start-up control a. On the other hand, when the carriage 102 performs the scanning speed start-up control b, the posture is tilted more in the constant speed section than with the scanning speed start-up control a, so that the landing position shifts in bidirectional printing even if the registration adjustment value of the scanning speed start-up control a is applied. In other words, the optimal registration adjustment value for bidirectional printing changes depending on the scanning speed start-up control.

[0049] In this embodiment, an example of a registration adjustment method for bidirectional printing is described in which start-up control of a first scanning speed of the carriage and start-up control of a second scanning speed of the carriage can be implemented even if the arrival speed of the carriage printing scan is the same.

[0050] Fig. 11 is a flowchart showing the process of determining the registration adjustment value in this embodiment. The series of processes shown in Fig. 11 are performed by the MPU 51 of the controller 60 expanding the program code stored in the ROMs 52 and 57 into the RAM 54 and executing it. Alternatively, some or all of the functions of the steps in Fig. 11 may be realized by hardware such as the ASIC 53 or an electronic circuit. Note that the symbol "S" in the explanation of each process indicates that it is a step in the flowchart.

[0051] First, in S1101, the controller 60 obtains the print scanning speed X of the carriage 102 and the start-up control a of the first scan speed. In S1102, the controller 60 prints, using the print head 103, a registration adjustment pattern used in the registration adjustment process for bidirectional printing at the print scanning speed X and the start-up control a of the first scan speed. That is, as described above, the first nozzle row is used to print a reference pattern in the forward direction and a shift pattern in the backward direction. In S1103, the controller 60 measures the optical reflectance of each registration adjustment pattern with the optical sensor 200 to determine a registration adjustment value. In S1104, the controller 60 stores the registration adjustment value for bidirectional printing at the print scanning speed X of the carriage 102 and the start-up control a of the first scan speed in the storage area A of the RAM 54. Note that, although the first nozzle row has been described as an example here, when multiple nozzle rows need to be adjusted, the adjustment pattern may be printed with each nozzle row to measure the optical reflectance and determine the registration adjustment value.

[0052] Next, in S1105, the controller 60 determines whether the printing scanning speed of the carriage 102 is X and whether the start-up control b of the second scanning speed can be set. The start-up control b of the second scanning speed is different from the start-up control a of the first scanning speed described above. For example, the determination in S1105 may be made based on whether borderless printing or bordered printing can be set. In addition, it may be determined by various settings whether a start-up control different from the start-up control a of the first scanning speed can be set at the printing scanning speed X in the recording apparatus 100. If the start-up control b of the second scanning speed cannot be set, the registration adjustment ends.

[0053] On the other hand, if the second scanning speed start-up control b can be set, in S1106, the controller 60 acquires the print scanning speed X of the carriage 102 and the second scanning speed start-up control b. In S1107, the controller 60 prints, using the print head 103, a registration adjustment pattern used in the registration adjustment process for bidirectional printing at the print scanning speed X of the carriage 102 and the second scanning speed start-up control b. In S1108, the controller 60 measures the optical reflectance of each registration adjustment pattern with the optical sensor 200 to determine a registration adjustment value. In S1109, the controller 60 stores the registration adjustment value for bidirectional printing at the print scanning speed X of the carriage 102 and the second scanning speed start-up control b in the storage area B of the RAM 54. As described above, if there are multiple nozzle rows to be adjusted, the registration adjustment values ​​corresponding to the multiple nozzle rows are stored.

[0054] FIG. 12 is a diagram showing an example of a storage area for bidirectional printing registration adjustment values ​​in this embodiment. As shown in FIG. 12, the registration adjustment values ​​for the print scanning speed X and the start-up control a of the first scanning speed of the carriage 102 are stored in the storage area A, and the registration adjustment values ​​for the print scanning speed X and the start-up control b of the second scanning speed of the carriage 102 are stored in the storage area B. The registration adjustment value is an adjustment value of a relative difference in the return direction with respect to the reference forward direction. When printing based on print data is performed, the controller 60 sets the print scanning speed and the start-up control of the scanning speed according to the printing purpose of the recording. Then, the controller 60 acquires the registration adjustment value corresponding to the set print scanning speed and the start-up control of the scanning speed from the storage area shown in FIG. 12. Then, the controller 60 adjusts the ejection timing based on the acquired registration adjustment value, so that ink can be ejected at an appropriate printing position during bidirectional printing. For example, when a reference pattern is printed in the forward direction, the ejection timing may be adjusted based on the acquired registration adjustment value for printing in the return direction.

[0055] The recording scan speed and the start-up control of the scanning speed can be determined based on the settings of the print job. For example, the printing purpose of the printed matter may be set to be borderless printing or bordered printing in the print job. The controller 60 sets the recording scan speed and the start-up control of the scanning speed according to the printing purpose specified from the print job. Then, the controller 60 applies the bidirectional recording registration adjustment value stored in the storage area that corresponds to the set recording scan speed and the start-up control of the scanning speed, thereby enabling accurate bidirectional recording for each print job.

[0056] In this embodiment, the carriage scanning speed start-up control is changed even when the carriage recording scanning speed is the same, using the example of bordered printing and borderless printing, but this is not limited to this example. For example, the carriage scanning speed start-up control may be changed even when the carriage recording scanning speed is the same depending on the printing purpose, such as an image-centered image or a text-centered image. Also, the carriage scanning speed start-up control may be changed even when the carriage recording scanning speed is the same depending on the paper type, such as glossy paper, coated paper, and plain paper. This embodiment can be applied to such cases as well.

[0057] <<Second embodiment>> In the first embodiment, an example of a registration adjustment method for bidirectional printing in a case where the arrival speed of the carriage's printing scan is the same and start-up control of the first scanning speed of the carriage and start-up control of the second scanning speed of the carriage can be set is described. In the second embodiment, an example is further described in which the arrival speed of the carriage's printing scan is the same and start-up control of a third scanning speed different from the start-up control of the first scanning speed of the carriage and the start-up control of the second scanning speed of the carriage is performed.

[0058] In the second embodiment, it is assumed that the arrival speed of the carriage printing scan is the same, and the bidirectional printing registration adjustment values ​​for both the known carriage first scanning speed start-up control and the known second scanning speed start-up control are already stored. An example will be described in which the bidirectional printing registration adjustment value for the unknown third scanning speed start-up control is determined from these known registration adjustment values.

[0059] If the printing scanning speed (arrival speed) is the same, the amount of carriage posture fluctuation is determined by the magnitude of the scanning speed startup control (magnitude of acceleration). Therefore, the amount of carriage posture fluctuation is proportional to the magnitude of the scanning speed startup control (magnitude of acceleration). Taking advantage of this point, in this embodiment, a registration adjustment value according to the scanning speed startup control is obtained.

[0060] FIG. 13 is a diagram for explaining an example of determining a registration adjustment value in a third speed start-up control from registration adjustment values ​​corresponding to the scanning speed start-up controls at two known points. Note that the carriage printing speed reaches the same speed in both cases. As shown in the figure, the start-up controls at two scanning speeds (5 m / s 2 ,15m / s 2 The registration adjustment values ​​corresponding to the first scanning speed start-up control (5 m / s 2 ) corresponds to the registration adjustment value of "5", and the second scanning speed start-up control (15 m / s 2 The registration adjustment value corresponding to the unknown third scanning speed (10 m / s 2 13, a registration adjustment value of "7" can be obtained by linear interpolation. In this way, a registration adjustment value corresponding to start-up control of an unknown scanning speed can be obtained by linear interpolation from a registration adjustment value corresponding to start-up control of a known scanning speed and the magnitude of the scanning speed in the start-up control. This makes it possible to reduce the number of items to be adjusted for registration in bidirectional printing, and also shorten the time required for registration adjustment.

[0061] In the present embodiment, an example in which the registration adjustment value for bidirectional printing is determined (calculated) by linear interpolation has been described, but the present invention is not limited to this example. For example, the interpolation may be performed using an approximation curve. Also, the registration adjustment value corresponding to the unknown scanning speed start-up control may be determined from the registration adjustment values ​​corresponding to the three known scanning speed start-up controls. That is, the magnitudes of the scanning speeds of the known carriage start-up control of the first scanning speed, the second scanning speed, and the third scanning speed, and the registration adjustment values ​​for bidirectional printing corresponding to each start-up control are obtained. Then, from these obtained values, the registration adjustment value for bidirectional printing corresponding to the unknown fourth scanning speed start-up control may be obtained from an approximation formula.

[0062] <<Third embodiment>> In the second embodiment, an example was described in which a bidirectional registration adjustment value corresponding to the start-up control of an unknown third scanning speed is determined from a bidirectional registration adjustment value corresponding to the start-up control of two known scanning speeds. In the third embodiment, a registration adjustment value corresponding to the start-up control of a first scanning speed at a known first printing scanning speed (arrival speed) and a registration adjustment value corresponding to the start-up control of a second scanning speed at a known first printing scanning speed are used. In addition, a bidirectional registration adjustment value corresponding to the start-up control of a first scanning speed at a known second printing scanning speed is used. Then, an example is described in which a bidirectional registration adjustment value of the start-up control corresponding to a second scanning speed at an unknown second printing scanning speed is determined from these values. In the following, an example is described in which a registration adjustment value is determined using an acceleration time after a difference between the registration adjustment values ​​corresponding to the start-up control of the scanning speed is obtained.

[0063] FIG. 14 is a diagram for explaining an example of determining a registration adjustment value based on a registration adjustment value corresponding to the start-up control of the scanning speed at two points at a first printing scanning speed and a registration adjustment value corresponding to the start-up control of the scanning speed at one point at a second printing scanning speed. As shown in the figure, the known registration adjustment values ​​stored in the storage area are as follows: Start-up control of the first scanning speed (15 m / s) at the first printing scanning speed (500 mm / s) 2 The registration adjustment value corresponding to the first printing scanning speed (500 mm / s) is "9". 2 The registration adjustment value corresponding to the second scanning speed (250 mm / s) is "5". 2 ) the corresponding registration adjustment value is "5".

[0064] Here, the start-up control of the first scanning speed (15 m / s) at the first recording scanning speed (500 mm / s) 2 ) and second scanning speed startup control (5m / s 2 ) the difference in registration adjustment value is "4".

[0065] Here, the difference in the registration adjustment value due to the posture change in the start-up control of the two different scanning speeds varies depending on the printing scanning speed (attainment speed). This is because the time required to reach the attainment speed, i.e., the acceleration time, differs depending on the attainment speed, and as a result, the posture change of the carriage changes. For example, the speed ratio of the second printing scanning speed (250 mm / s) to the first printing scanning speed (500 mm / s) in this example is 1 / 2. In this case, the acceleration time to reach the second printing scanning speed (250 mm / s) is 0.5 times the acceleration time to reach the first printing scanning speed (500 mm / s). In this case, the difference between the registration adjustment value due to the posture change in the start-up control of the first scanning speed at the second printing scanning speed and the registration adjustment value due to the posture change in the start-up control of the second scanning speed is 1 / 2 according to the speed ratio. That is, this difference is half the difference between the registration adjustment value due to posture variation in the start-up control of the first scanning speed at the first printing scanning speed and the registration adjustment value due to posture variation in the start-up control of the second scanning speed. Specifically, applying this to the example of FIG. 14, the registration adjustment value due to posture variation in the start-up control of the first scanning speed at the second printing scanning speed (250 mm / s) is 2 ) from the registration adjustment value corresponding to the second scanning speed start control (5 m / s 2 The difference in the registration adjustment value corresponding to the unknown second printing scanning speed (250 mm / s) is "2". 2 ) can be found to be "3." In this way, the difference in the registration adjustment value due to the posture variation during the start-up control of the scanning speed can be found, and the registration adjustment value corresponding to the start-up control of the unknown scanning speed can be determined using the found difference.

[0066] In this manner, in this embodiment, the magnitudes of the first scanning speed startup control at the first recording scanning speed, the second scanning speed startup control, and the first scanning speed startup control at the second recording scanning speed, which are known, are acquired. Also, the bidirectional recording registration adjustment values ​​corresponding to these are acquired. Then, from the acquired values, it is possible to determine the bidirectional recording registration adjustment value corresponding to the unknown second scanning speed startup control at the second recording scanning speed. This makes it possible to set an appropriate registration adjustment value. The recording device 100 may be capable of setting multiple carriage recording scanning speeds and scanning speed startup controls to accommodate a wide variety of paper types. Even in such a case, according to this embodiment, the number of items to be registered can be reduced, and the registration adjustment time can be shortened.

[0067] <<Fourth embodiment>> In the first, second and third embodiments, examples of registration adjustment in bidirectional printing have been described, but in the fourth embodiment, an example of registration adjustment in unidirectional printing will be described.

[0068] 15 is a diagram for explaining landing deviation caused by carriage posture fluctuation. As described in the first embodiment, the amount of posture fluctuation of the carriage 102 changes depending on whether the scanning speed start-up control is a or b.

[0069] 16 is a diagram for explaining landing deviation in one-way printing. The print start position for N scan is the left edge of recording medium P, and the print start position for N+1 scan is the center of recording medium P. For example, if the recording data corresponding to N scan indicates that there are pixels to be recorded at least on the left edge of recording medium P, N scan starts printing from the left edge of recording medium P. On the other hand, if the recording data corresponding to N+1 scan indicates that there are no pixels to be recorded on the left edge of recording medium P, but there are pixels to be recorded in the center or to the right side of recording medium P, N+1 scan starts printing from the center of recording medium P.

[0070] In the N scan, the carriage 102 moves to the left edge of the recording medium P, so preliminary ejection can be performed outside the left edge of the recording medium P. On the other hand, in the N+1 scan, the print start position is the center of the recording medium P, and movement time occurs when the carriage 102 moves for preliminary ejection to the outside left edge of the recording medium P. Therefore, the N+1 scan starts scanning from the center of the recording medium P (by controlling the start-up of the scanning speed), and the movement time until preliminary ejection to the outside right edge of the recording medium P is shortened.

[0071] As mentioned above, if printing is performed during acceleration, the ejection position is not stable, so it is preferable to print at a constant speed. For this reason, in order to shorten the acceleration distance, the N scan is configured to have a larger scanning speed startup control than the N+1 scan. Therefore, in the N scan and the N+1 scan, one-way printing is performed with different scanning speed startup controls. In other words, the landing positions of the scanning speed startup controls a and b are shifted. Therefore, the change in scanning speed startup control in one-way printing causes a shift in the landing position on the recording medium P.

[0072] 17 is a flowchart showing the process of determining the registration adjustment value of the fourth embodiment. First, in S1701, the controller 60 determines whether the start-up control a of the first scanning speed and the start-up control b of the second scanning speed can be set for the print scanning speed X of the carriage 102. In this example, an example is described in which it is determined whether the start-up controls of two scanning speeds can be set, but it is sufficient to determine whether the start-up controls of a plurality of scanning speeds can be set. If the start-up control a of the first scanning speed and the start-up control b of the second scanning speed cannot be set, the process ends.

[0073] On the other hand, if the first scanning speed start-up control a and the second scanning speed start-up control b can be set, in S1702 the controller 60 acquires the printing scanning speed X of the carriage 102 and the first scanning speed start-up control a. In S1703, the controller 60 prints the reference pattern using the printing scanning speed X of the carriage 102 and the first scanning speed start-up control a.

[0074] Next, in S1704, the controller 60 acquires the recording scanning speed X of the carriage 102 and the start-up control b of the second scanning speed. In S1705, the controller 60 prints the shift pattern at the recording scanning speed X of the carriage 102 and the start-up control b of the second scanning speed. In S1706, the controller 60 measures the optical reflectance of the registration adjustment pattern with the optical sensor 200 to determine the registration adjustment value. In S1707, the controller 60 stores the registration adjustment value for one-way printing from the start-up control a of the first scanning speed to the start-up control b of the second scanning speed at the recording scanning speed X of the carriage 102 in the storage area C of the RAM 54.

[0075] FIG. 18 is a diagram showing an example of a storage area of ​​the registration adjustment value of the fourth embodiment. The registration adjustment value of one-way printing from the first scanning speed start-up control a to the second scanning speed start-up control b at the printing scanning speed X of the carriage 102 is stored in the storage area C. The controller 60 applies the correction amount of the ink ejection timing during one-way printing with the stored registration adjustment value every time the speed start-up control for the printing scanning speed of the printing scanning changes from the speed start-up control a to the speed start-up control b. Note that when returning to the scanning speed start-up control a, the ink is ejected without using the registration adjustment value because the ink is returned to the standard. This allows the printing position of the dots in one-way printing to be adjusted with high precision. In this embodiment, the registration adjustment value to be applied can change depending on the printing scanning.

[0076] As in the second embodiment, a registration adjustment value for the unknown start-up control of the third scanning speed may be determined from a registration adjustment value corresponding to the start-up control of the first scanning speed of the carriage, which is known, and a registration adjustment value corresponding to the start-up control of the second scanning speed. In this embodiment, the start-up control of the first scanning speed is used as a reference, so a registration adjustment value corresponding to the start-up control of the third scanning speed with respect to the start-up control of the first scanning speed is obtained.

[0077] Furthermore, similarly to the third embodiment, registration adjustment values ​​corresponding to the start-up control at the first scanning speed of the carriage, the start-up control at the second scanning speed, and the start-up control at the first scanning speed of the second printing scanning speed, which are known, are obtained. Then, from these values, a registration adjustment value corresponding to the start-up control at the second scanning speed at the unknown second printing scanning speed may be determined. Note that, since the start-up control at the first scanning speed is used as the basis in this embodiment, a registration adjustment value corresponding to the start-up control at the second scanning speed for the start-up control at the first scanning speed of the second printing scanning speed is obtained.

[0078] <<Other embodiments>> In the above embodiment, an example has been described in which the registration adjustment values ​​are temporarily stored in RAM 54 of recording device 100 and then stored in ROM 52, but they may also be stored in a storage device outside recording device 100. Recording device 100 may perform the above-mentioned processing by referring to the registration adjustment values ​​stored externally.

[0079] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a 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 implements one or more of the functions. [Explanation of symbols]

[0080] 103 Recording head 200 Optical Sensor 60 Controller

Claims

1. An inkjet recording apparatus having a recording head with a nozzle row in which nozzles for ejecting ink are arranged, and performing bidirectional recording on a recording medium by reciprocating scanning of the recording head in a direction different from the direction of the nozzle arrangement, a setting means for setting either a first speed start-up control for controlling start-up up to a first ultimate speed which is a print scanning speed when printing, or a second speed start-up control which is a start-up control at a speed faster than the first speed start-up control; an acquisition means for acquiring a correction value corresponding to the start-up control set by the setting means, out of a first correction value which is corresponding to the first speed start-up control and corrects a deviation in the landing position caused by the nozzle row, and a second correction value which is corresponding to the second speed start-up control and corrects a deviation in the landing position caused by the nozzle row; a correction means for correcting ink ejection timing based on the correction value acquired by the acquisition means; Equipped with the inkjet recording apparatus is capable of recording at a second ultimate speed which is a second recording scanning speed different from the recording scanning speed; the setting means is capable of setting either the first speed start-up control or the second speed start-up control as the second reaching speed, a determination means for determining a fifth correction value corresponding to the second speed start-up control for controlling a start-up to the second reaching speed, based on the first correction value, the second correction value, and a fourth correction value corresponding to the first speed start-up control for controlling a start-up to the second reaching speed, The inkjet recording apparatus is characterized in that the acquisition means acquires the fifth correction value determined by the determination means when the second speed start-up control is set by the setting means as a start-up to the second reaching speed.

2. the first correction value is obtained by detecting a positional deviation from a first adjustment pattern formed at the first attainment speed reached by start-up control of the first speed; 2. The inkjet recording apparatus according to claim 1, wherein the second correction value is obtained by detecting a positional deviation from a second adjustment pattern formed at the first attainment speed reached by start-up control of the second speed.

3. 3. The inkjet recording apparatus according to claim 1, wherein the setting unit sets the first speed start-up control or the second speed start-up control in accordance with a setting of a printing purpose.

4. 4. The inkjet recording apparatus according to claim 3, wherein the setting of the printing purpose includes setting whether the print will have a border or not.

5. 4. The inkjet recording apparatus according to claim 3, wherein the setting of the printing purpose includes setting of an image-centered image or a text-centered image.

6. 4. The inkjet recording apparatus according to claim 3, wherein the setting of the printing purpose includes a setting of a paper type.

7. The setting means is configured to be further capable of setting a third speed start-up control for controlling a start-up to the first reaching speed, a determination means for determining a third correction value corresponding to a third speed start-up control for controlling a start-up to the first reaching speed, based on the first correction value and the second correction value; 7. The inkjet recording apparatus according to claim 1, wherein the acquisition means acquires the third correction value determined by the determination means when the third speed start-up control is set by the setting means.

8. 8. The inkjet recording apparatus according to claim 7, wherein the determining unit determines the third correction value by linearly interpolating the first correction value and the second correction value in accordance with the speeds in the start-up controls of the first and second correction values.

9. 9. An inkjet recording apparatus according to claim 1, wherein the determination unit determines the fifth correction value by calculating a difference between the fourth correction value and the fifth correction value from a difference between the first correction value and the second correction value and a speed ratio between the first reaching speed and the second reaching speed.

10. A recording method using an inkjet recording apparatus having a recording head with a nozzle row in which nozzles for ejecting ink are arranged, the recording head being caused to perform bidirectional recording on a recording medium by reciprocating scanning in a direction different from the nozzle arrangement direction, the method comprising: a setting step for setting either a first speed start-up control for controlling start-up up to a first ultimate speed which is a print scanning speed when printing, or a second speed start-up control which is a start-up control at a speed faster than the first speed start-up control; an acquisition step of acquiring a correction value corresponding to the start-up control set in the setting step, out of a first correction value corresponding to the first speed start-up control and configured to correct a deviation in the landing position due to the nozzle array, and a second correction value corresponding to the second speed start-up control and configured to correct a deviation in the landing position due to the nozzle array; a correction step of correcting the ink ejection timing based on the correction value acquired in the acquisition step; Equipped with the inkjet recording apparatus is capable of recording at a second ultimate speed which is a second recording scanning speed different from the recording scanning speed; In the setting step, as the start-up control up to the second reaching speed, either the start-up control at the first speed or the start-up control at the second speed can be set, a determination step of determining a fifth correction value corresponding to the second speed start-up control for controlling a start-up to the second reaching speed, based on the first correction value, the second correction value, and a fourth correction value corresponding to the first speed start-up control for controlling a start-up to the second reaching speed, a fifth correction value determined by the determination step when the second speed start-up control is set by the setting means as a start-up to the second reaching speed, the fifth correction value determined by the determination step is obtained in the acquisition step.

Images