Liquid dispensing device

Abstract

To provide a liquid discharge device which can correct the impact position deviation of liquid to a recording medium in a short time.SOLUTION: A liquid discharge device according to an embodiment of the present invention comprises a head having a plurality of nozzle arrays in which a plurality of nozzles for discharging liquid are arrayed along a prescribed direction. The liquid discharge device forms an image in a recording medium. The liquid discharge device comprises: a detection unit which detects the impact position of the liquid discharged from the nozzle array to the recording medium; a correction unit which corrects the impact position on the basis of the detection result by the detection unit; and a storage unit which stores information about a relation between the impact positions of the liquid discharged from each of the plurality of nozzle arrays. The detection unit detects the impact position of the liquid discharged from the predetermined one representative nozzle array in the plurality of nozzle arrays. The correction unit corrects the impact positions of all the nozzle arrays on the basis of the detection result of the impact position of the representative nozzle array by the detection unit and the information about the relation between the impact positions stored in the storage unit.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, liquid ejection devices that eject liquid onto a recording medium to form an image are known.

[0003] Also disclosed is a liquid ejection device that forms an image on a recording medium by performing a main scan of a carriage equipped with a head that ejects liquid in both directions, and corrects the deviation of the position where the liquid lands on the recording medium (landing position) on the outward and return paths in the main scanning direction (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional configurations such as those described in Patent Document 1, correction of the impact position deviation is performed for all of the multiple nozzle rows included in the head every time the distance between the head and the recording medium is changed, which raises concerns that the correction takes a long time.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejection apparatus that can correct, in a short time, deviations in the landing position of liquid on a recording medium. [Means for solving the problem]

[0006] A liquid ejection device according to one aspect of the present invention is a liquid ejection device that includes a head having a plurality of nozzle rows in which a plurality of nozzles that eject liquid are arranged in a predetermined direction, and that forms an image on a recording medium, the liquid ejection device comprising: a detection unit that detects a landing position on the recording medium of the liquid ejected from the nozzle rows; and a correction unit that corrects the landing position based on the detection result by the detection unit; Complex number of The aforementioned a storage unit that stores information relating to the relationship between the landing positions of the liquid ejected from each nozzle row, and the detection unit Complex number of The aforementioned The landing positions of the liquid ejected from one predetermined representative nozzle row among the nozzle rows are detected, and the correction unit calculates the landing positions based on the detection result of the landing positions of the representative nozzle row by the detection unit and information related to the relationship between the landing positions stored in the storage unit. Complex number of The aforementioned Correct the landing positions of all nozzle rows the detection unit detects the landing position of the liquid ejected from the representative nozzle array based on a predetermined correction pattern formed on the recording medium by the liquid ejected from the representative nozzle array, the correction pattern being a correction pattern including three linear patterns each extending along the predetermined direction and arranged in a direction perpendicular to the predetermined direction, and being one correction pattern formed on the recording medium by the liquid ejected from one of the representative nozzle arrays. . [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a liquid ejection device that can correct deviations in the landing position of liquid on a recording medium in a short period of time. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating an example of the configuration of a liquid ejection device according to an embodiment. [Figure 2] 1 is a side view illustrating an example of the configuration of a liquid ejection device according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a carriage according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of an imaging unit according to the embodiment. [Figure 5] FIG. 2 is a block diagram showing an example of the configuration of a main control board according to the embodiment. [Figure 6] FIG. 2 is a block diagram illustrating an example of a functional configuration of a main control board according to the embodiment. [Figure 7] 5A to 5C are diagrams illustrating correction patterns according to an embodiment. [Figure 8] 10A to 10C are diagrams illustrating a correction method used by the liquid ejection device according to the embodiment. [Figure 9] FIG. 10 is a flowchart showing an example of a correction operation performed by the liquid ejection device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0010] In the figures shown below, directions may be indicated by the X-axis, Y-axis, and Z-axis, but the X-direction along the X-axis indicates the main scanning direction, which is the direction of movement of a carriage provided in the liquid ejection device according to the embodiment, the Y-direction along the Y-axis indicates the sub-scanning direction, which is the direction of movement of a recording medium, and the Z-direction along the Z-axis indicates the direction perpendicular to both the main scanning direction and the sub-scanning direction.

[0011] Furthermore, the direction in which the arrow points in the X direction will be referred to as the +X direction, and the direction opposite to the +X direction will be referred to as the -X direction. The direction in which the arrow points in the Y direction will be referred to as the +Y direction, and the direction opposite to the +Y direction will be referred to as the -Y direction. Furthermore, the direction in which the arrow points in the Z direction will be referred to as the +Z direction, and the direction opposite to the +Z direction will be referred to as the -Z direction. However, these do not limit the orientation of the liquid ejection device when in use, and the orientation of the liquid ejection device is arbitrary.

[0012] [Embodiment] <Configuration example of liquid ejection device 100> The configuration of the liquid ejection device 100 will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the liquid ejection device 100 according to an embodiment, viewed from the +Z direction. Figure 2 is a side view of the liquid ejection device 100, viewed from the +X direction.

[0013] The liquid ejection device 100 is a serial image forming device that ejects ink, which is an example of a liquid, while moving a head in the main scanning direction to form an image on roll paper, which is an example of a recording medium.

[0014] 1, the liquid ejection device 100 includes a device main body 101, a paper feeder 102 arranged below the device main body 101, and a winding device 103 arranged on the -Z direction side of the device main body 101. The paper feeder 102 may be arranged separately from the device main body 101 on the -Z direction side of the device main body 101, or may be configured integrally with the device main body 101 as shown in FIG. 2. The winding device 103 may also be arranged separately from the device main body 101 on the -Z direction side of the device main body 101, or may be configured integrally with the device main body 101 as shown in FIG. 2.

[0015] As shown in FIG. 2, inside the device main body 101, there are provided a paper feeding device 102 that feeds roll paper 120, which is a roll-shaped recording medium, a winding device 103 that winds up the roll paper 120, which is a roll-shaped recording medium, and an image forming unit 104 that forms an image on the roll paper 120.

[0016] The image forming unit 104 includes guides 1, which are guide members fixed to both side plates provided on the liquid ejection device 100. The guides 1 support the carriage 5 so that it can move in the X direction (main scanning direction, carriage movement direction).

[0017] 1, the liquid ejection device 100 is provided with a main scanning motor 8, which is provided on one side in the X direction and serves as a drive source for reciprocating a carriage 5. A timing belt 11 is wound between a drive pulley 9, which is rotationally driven by the main scanning motor 8, and a driven pulley 10, which is provided on the other side in the X direction. A belt holding portion of the carriage 5 is fixed to the timing belt 11, and when the main scanning motor 8 is driven, the carriage 5 reciprocates in the X direction.

[0018] The carriage 5 integrally mounts multiple heads and multiple head tanks that supply ink to each of the multiple heads. The heads are equipped with multiple nozzle rows in which multiple nozzles that eject ink are arranged along the Y direction (sub-scanning direction) that is perpendicular to the X direction. The heads are also equipped with these nozzle rows so that the ink ejection direction is along the -Z direction.

[0019] The liquid ejection device 100 is provided with an encoder sheet 12 along the movement direction of the carriage 5. The carriage 5 is provided with an encoder sensor that reads the encoder sheet 12. The encoder sheet 12 and the encoder sensor form a linear encoder, and the liquid ejection device 100 can detect the position and speed of the carriage 5 from the output of the linear encoder.

[0020] The liquid ejection device 100 uses a paper feed device 102 to feed the roll paper 120 to a formation area within the main scanning area of ​​the carriage 5 where an image is formed on the roll paper 120. The liquid ejection device 100 also uses a conveying means 21 to intermittently convey the roll paper 120 in the Y direction, which is perpendicular to the main scanning direction of the carriage 5.

[0021] 1, the liquid ejection device 100 includes an ink cartridge 50, which is a main tank that is replaceably mounted in a device main body 101. The ink cartridge 50 supplies ink of each color to a head tank of the head via a supply tube. The liquid ejection device 100 also includes a maintenance and recovery mechanism 80, which performs head maintenance and recovery, on one side in the X direction, beside the transport guide member 25.

[0022] 2, the conveying means 21 includes a conveying roller 23 that conveys the roll paper 120 fed from the paper feeder 102, and a pressure roller 24 that is disposed opposite the conveying roller 23. The liquid discharger 100 includes, downstream of the conveying roller 23, a conveying guide member 25 that has multiple suction holes formed therein, and a suction fan 26 as suction means that draws suction through the suction holes in the conveying guide member 25.

[0023] The paper feeder 102 is equipped with a roll body 112. The roll body 112 is formed by winding roll paper 120 in a roll shape around a hollow shaft 114, such as a cardboard tube, which serves as a core member. In this embodiment, the roll body 112 can be either one in which the end of the roll paper 120 is fixed to the hollow shaft 114 by gluing or other means, or one in which the end of the roll paper 120 is not fixed to the hollow shaft 114 and is not glued.

[0024] In FIG. 2, the liquid ejection device 100 includes a guide member 130 that guides the roll paper 120 pulled out from the roll body 112 of the paper feed device 102, and a paper discharge guide member 131 downstream of the conveying guide member 25 that guides the roll paper 120 after suction.

[0025] The winding device 103 has a hollow shaft 115 such as a paper tube that serves as a core member, and the leading end of the roll paper 120 is adhered to the hollow shaft 115 with an adhesive member such as tape.

[0026] During image formation, the liquid ejection device 100 moves the carriage 5 in the X direction and intermittently feeds the roll paper 120 fed from the paper feeder 102 using the transport means 21. The liquid ejection device 100 forms an image on the roll paper 120 by driving the head to eject ink in accordance with image data (image information). The liquid ejection device 100 guides the roll paper 120 on which the image has been formed using a paper discharge guide member 131, and winds it up around a hollow shaft 115 in the winding device 103.

[0027] The liquid ejection device 100 is provided with a cutter 27 as cutting means for cutting the roll paper 120 on which an image has been formed to a predetermined length on the downstream side of the paper discharge guide member 131 in the transport direction.

[0028] <Carriage 5 configuration example> The configuration of the carriage 5 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing an example of the configuration of the carriage 5. Fig. 3 shows the carriage 5 as viewed from the -Z direction side. Fig. 4 is a diagram showing an example of the configuration of the imaging unit 20 provided in the carriage 5.

[0029] 3, the carriage 5 is equipped with three heads 6a, 6b, and 6c arranged in a staggered arrangement. Hereinafter, when there is no need to distinguish between the heads 6a, 6b, and 6c, they will be collectively referred to as the head 6. The head 6 is supported by the carriage 5 so that the nozzle surface, on which the nozzles that eject ink are formed, faces in the -Z direction.

[0030] The head 6 has nozzle rows consisting of a large number of nozzles aligned in the Y direction (sub-scanning direction). Specifically, each of the heads 6a, 6b, and 6c has a nozzle row 60Y that ejects yellow (Y) ink, a nozzle row 60C that ejects cyan (C) ink, a nozzle row 60M that ejects magenta (M) ink, and a nozzle row 60K that ejects black (K) ink. When there is no need to distinguish between the nozzle rows 60Y, 60C, 60M, and 60K, they will be collectively referred to as nozzle row 60.

[0031] In other words, the head 6 has four nozzle rows 60 in which a plurality of nozzles that eject ink are arranged along the Y direction, which is an example of a predetermined direction. The liquid ejection device 100 has three heads 6, each of which has four nozzle rows 60, for a total of 12 nozzle rows 60.

[0032] The liquid ejection device 100 intermittently transports the roll paper 120 in the Y direction, and while the transport of the roll paper 120 is stopped, it moves the carriage 5 back and forth in the X direction, selectively ejecting ink from multiple nozzles included in the nozzle row 60 in accordance with image data, thereby forming an image on the roll paper 120.

[0033] The carriage 5 also includes an imaging unit 20 for capturing an image of the correction pattern P formed on the roll paper 120. The imaging unit 20 captures an image of the predetermined correction pattern formed on the roll paper 120 using ink ejected from a representative nozzle array, which will be described later.

[0034] 4, the imaging unit 20 includes a two-dimensional image sensor 201 such as a CCD sensor or a CMOS sensor, and an imaging lens 202 that forms an optical image of the correction pattern P formed on the roll paper 120 on the light receiving surface of the two-dimensional image sensor 201. The imaging unit 20 converts light incident via the imaging lens 202 into an electrical signal using the two-dimensional image sensor 201, and outputs the signal as a captured image of the correction pattern P.

[0035] The imaging unit 20 is attached to the carriage 5 by any mounting member, for example, in a state in which the optical axis of the imaging lens 202 is approximately perpendicular to the roll paper 120 set in the image formation area of ​​the liquid ejection device 100. Note that the imaging unit 20 need not necessarily be mounted on the carriage 5, as long as it is positioned so as to be able to properly capture an image of the correction pattern P formed on the roll paper 120.

[0036] <Configuration example of main control board 135> Next, a description will be given of the configuration of the main control board 135 provided in the liquid ejection device 100. Fig. 5 is a block diagram showing an example of the hardware configuration of the main control board 135.

[0037] 4, the main control board 135 includes a CPU (Central Processing Unit) 110, a ROM (Read Only Memory) 136, a RAM (Random Access Memory) 137, a head driver 138, a main scanning driver 105, a sub-scanning driver 106, and a control FPGA (Field-Programmable Gate Array) 125. The CPU 110, the ROM 136, the RAM 137, the head driver 138, the main scanning driver 105, the sub-scanning driver 106, and the control FPGA 125 are provided on the main control board 135. The head 6, the encoder sensor 13, and the imaging unit 20 are provided on the carriage 5.

[0038] The CPU 110 is responsible for overall control of the liquid ejection apparatus 100. For example, the CPU 110 uses the RAM 137 as a work area to execute various control programs stored in the ROM 136 and outputs control commands for controlling various operations in the liquid ejection apparatus 100. In particular, in the liquid ejection apparatus 100 according to this embodiment, the CPU 110 realizes functions such as a function for forming a correction pattern, a function as a distance measurement device, and a function for adjusting parameters related to the position of image formation based on the distance.

[0039] The head driver 138, the main scanning driver 105, and the sub-scanning driver 106 are drivers for driving the head 6, the main scanning motor 8, and the sub-scanning motor 14, respectively.

[0040] The control FPGA 125 cooperates with the CPU 110 to control various operations in the liquid ejection device 100. The control FPGA 125 includes, as functional components, a CPU control unit 121, a memory control unit 122, an ink ejection control unit 123, a sensor control unit 124, and a motor control unit 126, for example.

[0041] The CPU control unit 121 communicates with the CPU 110 to transmit various pieces of information acquired by the control FPGA 125 to the CPU 110 and also receives control commands output from the CPU 110 .

[0042] The memory control unit 122 performs memory control for the CPU 110 to access the ROM 136 and the RAM 137 .

[0043] The ink ejection control unit 123 controls the operation of the head driver 138 in response to a control command from the CPU 110 , thereby controlling the timing of ink ejection from the head 6 driven by the head driver 138 .

[0044] The sensor control unit 124 performs processing on sensor signals such as encoder values ​​output from the encoder sensor 13. For example, the sensor control unit 124 performs processing to calculate the position, movement speed, movement direction, etc. of the carriage 5 based on the encoder values ​​output from the encoder sensor 13.

[0045] The motor control unit 126 controls the operation of the main scanning driver 105 in response to control commands from the CPU 110, thereby controlling the main scanning motor 8 driven by the main scanning driver 105 and controlling the movement of the carriage 5 in the main scanning direction. The motor control unit 126 also controls the operation of the sub-scanning driver 106 in response to control commands from the CPU 110, thereby controlling the sub-scanning motor 14 driven by the sub-scanning driver 106 and controlling the movement of the roll paper 120 in the Y direction.

[0046] The above-described units are examples of control functions realized by the control FPGA 125, and various other control functions may be realized by the control FPGA 125. Also, all or part of the above control functions may be realized by a program executed by the CPU 110 or another general-purpose CPU. Also, part of the above control functions may be realized by dedicated hardware, such as another FPGA or an ASIC (Application Specific Integrated Circuit), different from the control FPGA 125.

[0047] The head 6 is driven by a head driver 138 whose operation is controlled by the CPU 110 and the control FPGA 125, and ejects ink onto the roll paper 120 to form an image.

[0048] The encoder sensor 13 detects the marks on the encoder sheet and outputs the obtained encoder value to the control FPGA 125. This encoder value is used by a sensor control unit 124 of the control FPGA 125 to calculate the position, movement speed, and movement direction of the carriage 5. The position, movement speed, and movement direction of the carriage 5 calculated by the sensor control unit 124 from the encoder value are sent to the CPU 110. The CPU 110 generates a control command for controlling the main scanning motor 8 based on the position, movement speed, and movement direction of the carriage 5 and outputs the control command to a motor control unit 126.

[0049] Under the control of the CPU 110, the imaging unit 20 captures an image of the correction pattern P formed on the roll paper 120 and outputs a captured image Im of the correction pattern P. The captured image Im of the correction pattern P output from the imaging unit 20 is sent to the control FPGA 125 and temporarily stored in a predetermined storage area such as the RAM 137.

[0050] The imaging unit 20 has a built-in function of converting analog signals obtained by photoelectric conversion of the two-dimensional image sensor 201 into digital image data through AD (Analog / Digital) conversion, and outputting the image data after performing various image processing such as shading correction, white balance correction, gamma correction, and image data format conversion. Various operating conditions of the two-dimensional image sensor 201 are set in accordance with various setting signals transferred from the CPU 110 via the control FPGA 125. Note that some or all of the various image processing operations on the image data may be performed outside the imaging unit 20.

[0051] In the liquid ejection device 100, the image forming unit 104 that forms an image on the roll paper 120 is made up of a head driver 138, a main scanning driver 105, and a sub-scanning driver 106, which are controlled by the CPU 110 and the control FPGA 125, and a head 6, a main scanning motor 8, and a sub-scanning motor 14, which are driven by these.

[0052] The functional configuration of the main control board 135 will be described with reference to FIGS.

[0053] Fig. 6 is a block diagram showing an example of the functional configuration of the main control board 135. Fig. 7 is a diagram illustrating the correction pattern P used by the liquid ejection device 100 to correct positional deviation.

[0054] 6, main control board 135 includes pattern forming unit 141, detection unit 142, correction unit 143, and storage unit 144. Main control board 135 realizes the functions of pattern forming unit 141, detection unit 142, and correction unit 143, for example, by CPU 110 using RAM 137 as a work area and executing a control program stored in ROM 136. Main control board 135 also realizes the function of storage unit 144, for example, by ROM 136 or the like.

[0055] In this embodiment, the main control board 135 forms a predetermined correction pattern P on the roll paper 120 using the pattern forming unit 141, and detects the position of the correction pattern P using the detection unit 142 based on the captured image Im of the formed correction pattern P captured by the imaging unit 20.

[0056] As shown in Figure 7, the correction pattern P includes three line patterns P0, P1, and P2 that are linear patterns extending along the Y direction and arranged along the X direction. Of the line patterns P0, P1, and P2, the line pattern P0 is the line pattern that serves as the reference for correcting deviation in the ink landing position. The two line patterns P1 and P2, formed on either side of the line pattern P0 in the X direction, are line patterns whose positions relative to the line pattern P0 are to be detected. Here, the ink landing position refers to the position where the liquid ejected from the head lands and is applied on the recording medium.

[0057] The imaging area 71 represents the area where the correction pattern P formed on the roll paper 120 is imaged by the imaging unit 20. The imaging unit 20 outputs the image Im of the imaging area 71 to the detection unit 142. The detection unit 142 detects the positions of the line patterns P1 and P2 relative to the line pattern P0 based on the image Im. The positions of the line patterns P1 and P2 correspond to the ink landing positions in the X direction.

[0058] The main control board 135 uses the position information of the line patterns P1 and P2 relative to the line pattern P0 detected by the detection unit 142 to correct, by the correction unit 143, the deviation of the ink landing positions of the line patterns P1 and P2 in the X direction.

[0059] Here, in order to correct the positional deviation of each of the 12 nozzle rows 60, the liquid ejection device 100 is required to correct the ink landing position in the X direction for each of 21 combinations of the 12 nozzle rows 60. Therefore, the correction time increases according to the number of combinations of the nozzle rows 60.

[0060] Furthermore, because a correction pattern P must be formed on the roll paper 120 for each combination of nozzle rows 60, the amount of roll paper 120 and the amount of ink used to correct the ink landing position increase according to the number of combinations of nozzle rows 60. The amount of roll paper 120 and the amount of ink used to correct the ink landing position are wasted because they are not used for forming the image intended by the liquid ejection device 100.

[0061] On the other hand, the deviation in the ink landing position changes depending on the change in the distance between the head 6 and the recording medium, which is dependent on the thickness of the recording medium, such as the roll paper 120. Therefore, it is not desirable to correct the deviation in the ink landing position every time the thickness of the recording medium is changed, as this takes a lot of time and results in a lot of wasted roll paper 120 and ink.

[0062] In this embodiment, the liquid ejection device 100 uses the detection unit 142 to detect the landing positions on the roll paper 120 of the ink ejected from the nozzle rows 60, and the correction unit 143 corrects the landing positions based on the detection results from the detection unit 142. The liquid ejection device 100 also uses the storage unit 144 to store information relating to the relationships between the landing positions of the ink ejected from each of the multiple nozzle rows 60.

[0063] In the liquid ejection device 100, the detection unit 142 detects the landing position of ink ejected from one predetermined representative nozzle array out of the multiple nozzle arrays 60, and the correction unit 143 corrects the landing positions of all of the multiple nozzle arrays 60 based on the detection result of the detection unit 142 for the landing position of the representative nozzle array and information relating to the relationship between the landing positions stored in the storage unit 144. As a result, it is only necessary to detect the landing position of ink ejected from one representative nozzle array, which shortens the time required to correct deviations in the ink landing position and also reduces waste of roll paper 120 and ink.

[0064] Each functional configuration will be described in more detail below.

[0065] The pattern forming unit 141 reads pattern data stored in advance in, for example, the ROM 136, and causes the image forming unit 104 to perform an image forming operation according to this pattern data, thereby forming a correction pattern P on the roll paper 120.

[0066] The correction pattern P formed on the roll paper 120 by the pattern forming unit 141 is imaged by the imaging unit 20. The captured image Im of the correction pattern P is stored in the RAM 137 or the like via the control FPGA 125 and temporarily held therein.

[0067] The detection unit 142 detects the landing position of the ink ejected from the nozzle row 60 onto the roll paper 120. The detection unit 142 detects the landing position of the ink ejected from the representative nozzle row based on, for example, an image Im of the correction pattern P captured by the imaging unit 20.

[0068] More specifically, the detection unit 142 reads out the captured image Im of the correction pattern P captured by the imaging unit 20 and stored in the RAM 137 or the like, and performs predetermined processing such as binarization processing on the captured image Im to detect the positions of the line patterns P0, P1, and P2 in the captured image Im by calculation.

[0069] Here, the representative nozzle row refers to one predetermined nozzle row among the multiple nozzle rows included in the liquid ejection device 100. There are no particular restrictions on which of the multiple nozzle rows is designated as the representative nozzle row. For example, in this embodiment, the representative nozzle row is nozzle row 60K in head 6a.

[0070] The position information detected by the detection unit 142 is position information on the two-dimensional coordinates of the image expressed in units of pixels. In many cases, the line patterns P0, P1, and P2 in the captured image Im are obtained as clusters of multiple pixels, and the detection unit 142 detects a predetermined position, such as the center of gravity of the cluster.

[0071] The detection unit 142 detects the positions (distances) of the line patterns P1 and P2 in the X direction relative to the line pattern P0 in the captured image Im in units of pixels. Using predetermined imaging magnification information of the imaging unit 20, the detection unit 142 converts the distances of the line patterns P1 and P2 in the X direction relative to the line pattern P0 in units of pixels into actual distances, which are actual distances expressed in units of millimeters, for example.

[0072] The detection unit 142 can detect the amount of misalignment s from the difference between the actual distance in mm of the line patterns P1 and P2 relative to the line pattern P0 in the X direction and the actual distance based on the original data of the line patterns P1 and P2 relative to the line pattern P0. The detection unit 142 outputs the detected position information to the correction unit 143.

[0073] The correction unit 143 corrects the landing position deviations of all 12 nozzle arrays 60 based on the detection result of the positional deviation amount s by the detection unit 142 and information related to the relationship between the landing positions stored in the storage unit 144. For example, the correction unit 143 corrects the landing positions of all 12 nozzle arrays 60 based on the detection result of the positional deviation amount s of ink ejected from the representative nozzle array and by referring to the information related to the relationship between the landing positions stored in the storage unit 144.

[0074] More specifically, the correction unit 143 refers to the storage unit 144 to obtain information indicating the positional relationship between the nozzle rows 60, and for each nozzle row 60, adds the information indicating the positional relationship with the representative nozzle row to the positional deviation s of the representative nozzle row to obtain the positional deviation amount s of all the nozzle rows 60.

[0075] The correction unit 143 corrects parameters related to image formation by the image forming unit 104 for all nozzle rows 60 according to the positional deviation amount s of all nozzle rows 60. Parameters related to image formation include, for example, parameters that control the ink ejection timing of the head 6 and parameters that control the movement speed of the carriage 5. The correction unit 143 can correct the control operations of the ink ejection control unit 123, the motor control unit 126, etc. by transmitting the correction values ​​of these parameters to the control FPGA 125.

[0076] The storage unit 144 stores in advance information relating to the relationship between the landing positions of ink ejected from each of the multiple nozzle rows 60. The information stored in the storage unit 144 is information that indicates the positional relationships between the nozzle rows 60, for example, in all 21 combinations of the nozzle rows 60.

[0077] When acquiring information to be stored in the storage unit 144, the liquid ejection device 100 causes the pattern forming unit 141 to form correction patterns P on the roll paper 120 for all combinations of nozzle rows 60. Then, the liquid ejection device 100 causes the imaging unit 20 to capture an image of the correction pattern P for each combination, the detection unit 142 to detect the amount of misalignment s for each combination, and stores the detected amount of misalignment s in the storage unit 144 in association with the combination.

[0078] The liquid ejection device 100 only needs to acquire the information to be stored in the storage section 144 once, for example, when the liquid ejection device 100 is shipped from the factory or when the liquid ejection device 100 is delivered to a customer, and does not need to acquire the information every time the thickness of the recording medium, etc. is changed.

[0079] The correction unit 143 detects the landing position of ink ejected from the representative nozzle array using the detection unit 142. The correction unit 143 acquires the landing position of ink ejected from nozzle arrays other than the representative nozzle array by referring to information stored in the storage unit 144 based on the detection result of the positional deviation amount s of the representative nozzle array, and corrects the landing position based on this acquired information.

[0080] <Method for correcting deviation of ink landing position by liquid ejection device 100> Fig. 8 is a diagram illustrating an example of a method for correcting deviation of ink landing positions in the X direction by the liquid ejection device 100. Fig. 8 shows a correction pattern P formed on a captured image Im.

[0081] 8, distance a is the distance in the X direction between the reference line pattern P0 and the line pattern P1 to be detected, and distance b is the distance in the X direction between the reference line pattern P0 and the line pattern P2 to be detected.

[0082] In the correction by the liquid ejection device 100, the detection unit 142 performs the following procedure.

[0083] (1) In the captured image Im, distances a and b are detected. The unit of distance in this case is the number of pixels.

[0084] (2) In the captured image Im, the amount of positional deviation s' of the line patterns P1 and P2 relative to the line pattern P0 is detected using the following equation: The unit of the amount of positional deviation s' is the number of pixels. (a+b) / 2-a=s'

[0085] (3) A ratio value f of the amount of positional deviation s' in the captured image Im to the width W' of the correction pattern P in the captured image Im is calculated using the following formula: Note that the width W' is the sum of the distance a and the distance b. s' / W'=f

[0086] (4) The ratio value f is multiplied by the actual width W of the correction pattern P formed on the roll paper 120 to detect the amount of misalignment s on the roll paper 120. The unit of the amount of misalignment s is [mm].

[0087] In this way, the liquid ejection device 100 can detect the amount of positional deviation s.

[0088] <Example of Correction Operation by Liquid Ejection Apparatus 100> Fig. 9 is a flowchart showing an example of a correction operation performed by the liquid ejection device 100. When the distance between the recording medium and the head 6 is changed, mainly due to a change in the thickness of the recording medium such as roll paper 120, the liquid ejection device 100 starts the operation shown in Fig. 9 in response to an instruction to start a landing position correction process by a user of the liquid ejection device 100 using an operation unit.

[0089] First, in step S91, the liquid ejection device 100 determines whether or not the storage unit 144 stores information relating to the relationship between the landing positions of ink ejected from each of the 12 nozzle arrays 60.

[0090] If it is determined in step S91 that the nozzles are not stored (step S91, No), in step S92, the liquid ejection device 100 causes the pattern forming unit 141 to form 21 correction patterns P on the roll paper 120 for each of the 21 combinations of the 12 nozzle rows 60.

[0091] Subsequently, in step S93, the liquid ejection device 100 causes the imaging unit 20 to capture images of the 21 correction patterns P, and passes the 21 captured images Im to the detection unit 142.

[0092] Subsequently, in step S94, the liquid ejection device 100 causes the detection unit 142 to detect 21 amounts of positional deviation s from the 21 captured images Im, and passes the detection results to the correction unit 143 and the storage unit 144, respectively.

[0093] Subsequently, in step S95, the liquid ejection device 100 stores the 21 positional deviation amounts s in the storage unit 144. Thereafter, the liquid ejection device 100 proceeds to step S100.

[0094] On the other hand, if it is determined in step S91 that the data is stored (step S91, Yes), in step S96, the liquid ejection device 100 forms one correction pattern P on the roll paper 120 using ink ejected from one representative nozzle row by the pattern forming unit 141.

[0095] Subsequently, in step S97, the liquid ejection device 100 causes the imaging unit 20 to capture an image of one correction pattern P, and passes the captured image Im to the detection unit 142.

[0096] Subsequently, in step S98, the liquid ejection device 100 causes the detection unit 142 to detect one positional deviation amount s from one captured image Im, and passes the detection result to the correction unit 143.

[0097] Next, in step S99, the correction unit 143 refers to the storage unit 144 and acquires the misalignment amounts s of the 20 nozzle rows 60 other than the representative nozzle row out of the 12 nozzle rows 60, based on the misalignment amount s of the representative nozzle row detected by the detection unit 142. The correction unit 143 acquires the misalignment amounts s of the 21 nozzle rows 60 in total, including the misalignment amount s of one representative nozzle row and the misalignment amount s of each of the 20 nozzle rows 60 other than the representative nozzle row.

[0098] Next, in step S100, the liquid ejection device 100 corrects the positional deviation of the 12 nozzle rows 60.

[0099] In this way, the liquid ejection device 100 can correct deviations in the landing positions of the ink ejected from each of the 12 nozzle arrays 60.

[0100] <Effects of the liquid ejection device 100> As described above, the liquid ejection device 100 according to the embodiment is a liquid ejection device that includes three heads 6, each having four nozzle rows 60 in which a plurality of nozzles that eject ink (liquid) are arranged along the Y direction (predetermined direction), and forms an image on roll paper 120 (recording medium). In this embodiment, there are a total of 12 nozzle rows 60.

[0101] The liquid ejection device 100 includes a detection unit 142 that detects the landing position of ink ejected from the nozzle array 60 onto the roll paper 120, a correction unit 143 that corrects the landing position based on the detection results by the detection unit 142, and a storage unit 144 that stores information relating to the relationship between the landing positions of ink ejected from each of the 12 nozzle arrays 60. A liquid ejection device.

[0102] The detection unit 142 detects the landing position of ink ejected from one predetermined representative nozzle row out of the 12 nozzle rows 60, and the correction unit 143 corrects the landing positions of all 12 nozzle rows 60 based on the detection result by the detection unit 142 of the landing position of ink ejected from the representative nozzle row and information related to the relationship between the landing positions stored in the storage unit 144.

[0103] For example, the correction unit 143 corrects the landing positions of ink ejected from nozzle rows 60 other than the representative nozzle row among the 12 nozzle rows 60, based on the detection results by the detection unit 142 of the landing positions of ink ejected from the representative nozzle row, by referring to information relating to the relationship between the landing positions stored in the storage unit 144.

[0104] Information relating to the relationship between the landing positions of ink ejected from each of the 12 nozzle arrays 60 is acquired only once, for example, when the liquid ejection device 100 is shipped from the factory or when the liquid ejection device 100 is delivered to a customer, and is stored in storage unit 144. After the information is stored in storage unit 144, the liquid ejection device 100 can correct the landing positions of all 12 nozzle arrays 60 by detecting only the landing position of ink ejected from one representative nozzle array. As a result, the liquid ejection device 100 can shorten the time required to correct misalignment of ink landing positions, and can provide a liquid ejection device that can quickly correct misalignment of ink landing positions on the roll paper 120.

[0105] Furthermore, the liquid ejection device 100 does not need to form 21 correction patterns P on the roll paper 120 to correct the misalignment of the landing position of the ink ejected from the nozzle row 60, so the amount of roll paper 120 and ink used for correction can be reduced, thereby reducing waste of roll paper 120 and ink.

[0106] Furthermore, in this embodiment, the detection unit 142 detects the landing position of ink ejected from the representative nozzle array based on a predetermined correction pattern P formed on the roll paper 120 by ink ejected from the representative nozzle array. This correction pattern P extends along the Y direction and includes line patterns P0, P1, and P2 (three linear patterns) arranged in the X direction (a direction perpendicular to the predetermined direction). With this configuration, it is possible to correct deviations in the ink landing position in the X direction using a simple correction pattern P.

[0107] This embodiment also includes an imaging unit 20 that captures an image of a predetermined correction pattern P formed on the roll paper 120 with ink ejected from the representative nozzle array. The detection unit 142 detects the landing positions of the ink ejected from the representative nozzle array based on the captured image Im of the correction pattern P captured by the imaging unit 20. With this configuration, the detection unit 142 can detect the distances between the line patterns P0, P1, and P2 in the correction pattern P by image processing of a two-dimensional image, thereby enabling accurate and highly robust detection of the distances between the line patterns P0, P1, and P2. As a result, the liquid ejection device 100 can accurately correct deviations in the landing positions of the ink ejected from the nozzle array 60.

[0108] [Other Preferred Embodiments] Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

[0109] For example, in the above-described embodiment, an inkjet printer has been mainly used as an example of a liquid ejection device, but the present invention is not limited to this. The liquid ejection device may also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices, post-processing devices, etc.

[0110] Examples of liquid ejection devices include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0111] Furthermore, the liquid ejection device is not limited to one that visualizes meaningful images such as letters and figures using the ejected liquid. For example, it also includes one that forms patterns that have no meaning in themselves, and one that forms three-dimensional images.

[0112] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0113] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0114] The "liquid" is not particularly limited as long as it has a viscosity and surface tension that allows it to be ejected from a head, but it is preferably one whose viscosity is 30 mPa·s or less at room temperature and normal pressure, or upon heating or cooling. More specifically, it is a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic devices or light-emitting elements, or electronic circuit resist patterns, and material liquids for 3D modeling.

[0115] Energy sources for ejecting liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode.

[0116] Other liquid ejection devices include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that sprays a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0117] In the terms used in the embodiments, image formation, recording, printing, copying, printing, modeling, and the like are all synonymous terms.

[0118] The embodiments include a liquid ejection method. For example, the liquid ejection method is a liquid ejection method using a liquid ejection device that includes a head having multiple nozzle arrays, each of which has a plurality of nozzles that eject liquid arranged in a predetermined direction, and that forms an image on a recording medium. The liquid ejection device includes a step of detecting, by a detection unit, a landing position on the recording medium of the liquid ejected from the nozzle arrays, a step of correcting, by a correction unit, the landing position based on the detection result by the detection unit, and a step of storing, by a storage unit, information relating to the relationship between the landing positions of the liquid ejected from each of the multiple nozzle arrays. The detection unit detects the landing position of the liquid ejected from one representative nozzle array among the multiple nozzle arrays, and the correction unit corrects the landing positions of all of the multiple nozzle arrays based on the detection result of the landing position of the representative nozzle array by the detection unit and the information relating to the relationship between the landing positions stored in the storage unit. This liquid ejection method can achieve the same effects as the liquid ejection device 100 described above.

[0119] The ordinal numbers, quantities, and other figures used in the description of the embodiments are all provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the illustrated figures. Furthermore, the connection relationships between the components are provided as examples to specifically explain the technology of the present invention, and do not limit the connection relationships that realize the functions of the present invention.

[0120] Each function of the embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and conventional circuit modules designed to perform each of the functions described above. [Explanation of symbols]

[0121] 1 Guide 5 Carriage 6 heads 8 Main scanning motor 9 Drive pulley 10 driven pulley 11 Timing belt 12 Encoder sheet 13 Encoder Sensor 14 Sub-scanning motor 20 Imaging unit 201 2D image sensor 202 Imaging Lens 21 Transportation 23 Conveyor roller 24 Pressure roller 25 Conveyor guide member 26 Suction fan 27 cutter 50 ink cartridges 60 nozzle rows 80 Maintenance and Recovery Mechanism 100 Liquid dispensing device 101 Device body 102 Paper feeder 103 Winding device 104 Image forming unit 105 Main scanning driver 106 Sub-scan driver 110 CPU 112 Roll body 114 Hollow shaft part 120 Roll paper (example of recording medium) 121 CPU control unit 122 Memory control unit 123 Ink discharge control unit 124 Sensor control unit 125 Control FPGA 126 Motor control unit 130 Guide member 131 Paper ejection guide member 135 Main control board 136 ROM 137 RAM 138 Head Driver 141 Pattern forming section 142 Detector 143 Correction Unit 144 Storage Unit Im Captured Image P Correction pattern P0, P1, P2 line patterns a, b distance W width [Prior art documents] [Patent documents]

[0122] [Patent Document 1] Patent No. 3624755

Claims

1. A liquid ejection device that includes a head having a plurality of nozzle rows in which a plurality of nozzles that eject liquid are arranged in a predetermined direction, and that forms an image on a recording medium, a detection unit that detects a landing position on the recording medium of the liquid ejected from the nozzle array; a correction unit that corrects the impact position based on the detection result by the detection unit; a storage unit that stores information relating to the relationship between the landing positions of the liquid ejected from each of the plurality of nozzle arrays, the detection unit detects the landing position of the liquid ejected from one predetermined representative nozzle row among the plurality of nozzle rows, the correction unit corrects the landing positions of all of the plurality of nozzle arrays based on the detection result of the landing positions of the representative nozzle array by the detection unit and information related to the relationship between the landing positions stored in the storage unit; the detection unit detects the landing position of the liquid ejected from the representative nozzle array based on a predetermined correction pattern formed on the recording medium by the liquid ejected from the representative nozzle array; The correction pattern is a correction pattern that includes three linear patterns that each extend along the predetermined direction and are arranged in a direction perpendicular to the predetermined direction, and is one correction pattern formed on the recording medium by liquid ejected from one of the representative nozzle rows.

2. an imaging unit that images the correction pattern; The liquid ejection device according to claim 1 , wherein the detection section detects the landing position of the liquid ejected from the representative nozzle array based on an image of the correction pattern captured by the imaging section.

3. The liquid ejection device according to claim 2, wherein the correction unit corrects the landing position of the liquid ejected from a nozzle array other than the representative nozzle array among the plurality of nozzle arrays, based on the detection result of the detection unit of the landing position of the representative nozzle array, and by referring to information relating to the relationship between the landing positions stored in the storage unit.

4. A liquid ejection method using a liquid ejection device that includes a head having a plurality of nozzle rows in which a plurality of nozzles that eject liquid are arranged in a predetermined direction, and that forms an image on a recording medium, the liquid ejection device comprising: detecting, by a detection unit, a landing position on the recording medium of the liquid ejected from the nozzle array; correcting the impact position by a correction unit based on the detection result by the detection unit; and storing, by a storage unit, information relating to the relationship between the landing positions of the liquid ejected from each of the plurality of nozzle rows; the detection unit detects the landing position of the liquid ejected from one representative nozzle row among the plurality of nozzle rows, the correction unit corrects the landing positions of all of the plurality of nozzle arrays based on the detection result of the landing positions of the representative nozzle array by the detection unit and information related to the relationship between the landing positions stored in the storage unit; the detection unit detects the landing position of the liquid ejected from the representative nozzle array based on a predetermined correction pattern formed on the recording medium by the liquid ejected from the representative nozzle array; A liquid ejection method in which the correction pattern includes three linear patterns that each extend along the predetermined direction and are arranged in a direction perpendicular to the predetermined direction, and the correction pattern is one correction pattern formed on the recording medium by liquid ejected from one of the representative nozzle arrays.

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