Recording device and correction value obtaining method

Abstract

To obtain an appropriate correction value while suppressing a medium and ink from being consumed, in recording a test pattern in order to obtain a correction value of a nozzle of a recording head.SOLUTION: A recording device comprises n-recording chips in which a plurality of nozzles that can discharge liquid to a medium is arranged, and a control part that controls discharging of the liquid by the nozzles, which can record a test pattern for obtaining a correction value of discharging characteristics of each nozzle on the medium, by the discharging of the liquid. The n-recording chips are arranged at different positions along a predetermined first direction. The control part records the test pattern on the medium using first chips that are m-chips (m is fewer than n) of the n-recording chips, and generates the correction value for the nozzles using second chips that are the recording chips, which have not been used in recording the test pattern, on the basis of the correction value of the nozzles using the first chips, obtained from the test pattern.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a printing apparatus and a correction value acquisition method. [Background technology]

[0002] A printing apparatus that employs an inkjet method has a print head that is composed of a printing chip with an array of multiple nozzles capable of ejecting liquid such as ink. Each nozzle has variation in the liquid ejection characteristics. Therefore, a technique is known in which correction values ​​and parameters for smoothing the variation in the ejection characteristics for each nozzle are obtained based on the read values ​​of the printing results of a test pattern, and the correction values ​​for each nozzle are applied to the printing data to obtain printing results with reduced density unevenness (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-9501 A Summary of the Invention [Problem to be solved by the invention]

[0004] To obtain correction values ​​for each of the nozzles of the print head, it is necessary to use a medium of a size that can be printed by all the print heads and to print a test pattern by ejecting liquid from all the nozzles of each print head. However, from the viewpoint of cost, a user may not have a medium of that size, or may not want to use a medium of that size to print a test pattern even if the user has a medium of that size. Thus, there is a problem that printing a test pattern to obtain the correction values ​​of the nozzles of all the print heads consumes a lot of medium and ink, and the cost increases. Therefore, there is a demand for an improvement that can obtain appropriate correction values ​​from a test pattern while solving such problems. [Means for solving the problem]

[0005] A recording device comprising n recording chips each having an array of nozzles capable of ejecting liquid onto a medium, and a control unit that controls the ejection of liquid by the nozzles, and capable of recording a test pattern onto the medium by the ejection of liquid to obtain a correction value for the ejection characteristics of each of the nozzles, wherein the n recording chips are arranged at different positions along a predetermined first direction, and the control unit records the test pattern onto the medium using first chips, which are m recording chips out of the n recording chips, the number of the first chips being less than n, and generates the correction value for the nozzles of a second chip, which is a recording chip that was not used to record the test pattern, based on the correction value for the nozzles of the first chip obtained from the test pattern.

[0006] A correction value acquisition method for acquiring a correction value for the ejection characteristics of each nozzle in n recording chips having an array of multiple nozzles capable of ejecting liquid onto a medium, the n recording chips being arranged at different positions along a predetermined first direction, the method comprising: a test pattern recording step of recording a test pattern for acquiring the correction value onto the medium by liquid ejection performed by m first chips, the m being less than n, of the n recording chips; and a correction value generation step of generating, based on the correction value of the nozzles of the first chip acquired from the test pattern, the correction value of the nozzles of a second chip, the second chip being a recording chip not used for recording the test pattern. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing a simplified device configuration. [Diagram 2] FIG. 2 is a diagram showing a simplified example of the relationship between a recording head and a medium as viewed from above. [Diagram 3] 4 is a flowchart showing a process relating to TP recording and correction value generation. [Figure 4] FIG. 13 is a diagram simply illustrating a state in which a TP is recorded on a medium as a result of step S120. [Diagram 5] FIG. 13 is a diagram illustrating an example of the correspondence relationship between the nozzles and the correction values ​​at the time when step S140 is completed and the correspondence relationship between the nozzles and the correction values ​​at the time when step S150 is completed. [Figure 6] FIG. 4 is a diagram illustrating an example of the correction value for each nozzle in table format. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that each drawing is merely an example for explaining the present embodiment. Since each drawing is an example, the ratios, shapes, shading, and numerical values ​​may not be accurate, may not match each other, and some parts may be omitted.

[0009] 1. Overview of the device configuration: 1 shows a simplified configuration of a recording apparatus 10 according to this embodiment. The recording apparatus 10 executes a correction value acquisition method. The recording device 10 includes a control unit 11, a display unit 13, an operation reception unit 14, a storage unit 15, a communication IF 16, a transport unit 17, and a recording head 18. IF stands for interface. The control unit 11 includes one or more ICs having a CPU 11a as a processor, a ROM 11b, a RAM 11c, and the like, and other non-volatile memories.

[0010] In the control unit 11, a processor, i.e., a CPU 11a, executes arithmetic processing according to a program 12 stored in a ROM 11b or other memory, using a RAM 11c or the like as a work area, thereby realizing various functions such as a TP recording control unit 12a and a correction value generating unit 12b. TP is an abbreviation for test pattern. The processor is not limited to one CPU, and may be configured to perform processing using multiple CPUs or a hardware circuit such as an ASIC, or may be configured to perform processing in cooperation with a CPU and a hardware circuit.

[0011] The display unit 13 is a means for displaying visual information, and is configured, for example, by a liquid crystal display, an organic EL display, etc. The display unit 13 may be configured to include a display and a drive circuit for driving the display.

[0012] The operation reception unit 14 is a means for receiving operations and inputs by a user, and is realized by, for example, a physical button, a touch panel, a mouse, a keyboard, etc. The display unit 13 and the operation reception unit 14 may be collectively called an operation panel. The operation reception unit 14 as a touch panel is realized as one function of the display unit 13.

[0013] The storage unit 15 is, for example, a hard disk drive, a solid state drive, or other memory-based storage means. A part of the memory of the control unit 11 may be regarded as the storage unit 15. The storage unit 15 may be regarded as a part of the control unit 11.

[0014] The communication IF 16 is a collective term for one or more IFs for the recording device 10 to communicate with an external device in a wired or wireless manner in accordance with a predetermined communication protocol including a known communication standard. The communication IF 16 corresponds to a communication unit. The external device is, for example, a communication device such as a personal computer (PC), a server, a smartphone, or a tablet terminal. In the example of FIG. 1, the recording device 10 is connected to a reading device 1, which is a type of external device, via the communication IF 16. The reading device 1 is a means for reading the medium 30 after recording, and may be a scanner or a colorimeter. There is no limit to the number of external devices that the recording device 10 can connect to for communication.

[0015] The conveying unit 17 is a means for conveying the medium 30 along a predetermined conveying direction under the control of the control unit 11. The conveying unit 17 includes, for example, a roller that rotates to convey the medium 30, and a motor as a power source for the rotation. The conveying unit 17 may be a mechanism that conveys the medium 30 by mounting the medium 30 on a belt, pallet, or drum. The medium 30 is typically paper, but may be any material that can be recorded on with a liquid, and various materials such as fabric and film can be used.

[0016] The transport unit 17 can be said to be a means for relatively moving the medium 30 and the recording head 18 in the transport direction. However, this relative movement may be realized by the movement of the recording head 18. In other words, the recording device 10 may have a mechanism such as a motor or rails that can reciprocate the recording head 18 along the transport direction, and the mechanism may move the recording head 18 relative to the medium 30 in the transport direction. In this case, the mechanism also corresponds to a type of transport unit that relatively moves the medium 30 and the recording head 18 in the transport direction.

[0017] The recording head 18 is a means for performing recording on the medium 30 by an inkjet method under the control of the control unit 11. The recording head 18 has a plurality of nozzles 20 capable of ejecting liquid onto the medium 30. The droplets ejected by the nozzles 20 are called dots. As will be described later, the recording head 18 is composed of a plurality of recording chips 19.

[0018] The recording device 10 is realized by a single printer in which the components shown in FIG. 1 are integrated. Alternatively, the recording device 10 may be a system realized by a plurality of devices connected to each other so as to be able to communicate with each other. The recording device 10 includes, for example, an information processing device that mainly functions as the control unit 11 and the operation panel, and a printer that performs recording by having a conveying unit 17 and a recording head 18. In this case, the information processing device can be regarded as a recording control device or an image processing device.

[0019] FIG. 2 shows a simplified example of the relationship between the recording head 18 and the medium 30 from a top view. Each of the white circles shown in FIG. 2 is an individual nozzle 20. The predetermined "first direction D1" is the longitudinal direction of the recording head 18. The "second direction D2" intersecting the first direction D1 is the "transport direction D2" of the medium 30 by the transport unit 17. The first direction D1 is also called the "width direction D1" of the medium 30. The length of the medium 30 in the width direction D1 is called the "medium width." In the example of FIG. 2, the intersection of the width direction D1 and the transport direction D2 is perpendicular or nearly perpendicular.

[0020] The transport unit 17 transports the medium 30 from upstream to downstream in the transport direction D2. The upstream and downstream in the transport direction D2 are simply referred to as upstream and downstream. According to Fig. 2, the recording head 18 is fixed at a predetermined position on the transport path of the medium 30. The transport unit 17 transports the medium 30 along the transport direction D2 in a state in which the medium 30 is positioned such that the center of the medium 30 in the width direction D1 basically coincides or nearly coincides with the center of the recording head 18 in the width direction D1.

[0021] The recording head 18 is configured by arranging a plurality of recording chips 19 along the width direction D1. In this embodiment, the number of recording chips 19 constituting the recording head 18 is also described as n. That is, n is a natural number meaning a plurality, and the n recording chips 19 are arranged at different positions along the width direction D1. Since they are at different positions along the width direction D1, the recording chips 19 may, for example, partially overlap each other in the width direction D1. In the example of FIG. 2, the number of recording chips 19 is three for space reasons, but it goes without saying that the number of recording chips 19 constituting the recording head 18 is not limited to three. It may be understood that the configuration and dimensions of each of the plurality of recording chips 19 are the same.

[0022] The recording head 18 ejects a plurality of types of ink. The ink may be of various colors such as cyan (C), magenta (M), yellow (Y), and black (K). The recording head 18 may be capable of ejecting white ink, ink of other colors, and various liquids such as reaction liquid and coating liquid. In the example of FIG. 2, one recording chip 19 includes nozzle rows 21C, 21M, 21Y, and 21K. A set of nozzles 20 that eject the same type of liquid and are arranged at regular or approximately regular intervals along a predetermined "nozzle arrangement direction D3" is called a nozzle row or a nozzle group.

[0023] The nozzle row 21C is a nozzle row in which a plurality of nozzles 20 that eject C ink are arranged. Similarly, the nozzle row 21M is a nozzle row in which a plurality of nozzles 20 that eject M ink are arranged, the nozzle row 21Y is a nozzle row in which a plurality of nozzles 20 that eject Y ink are arranged, and the nozzle row 21K is a nozzle row in which a plurality of nozzles 20 that eject K ink are arranged. In the example of FIG. 2, in the recording chip 19, the nozzle rows 21C, 21M, 21Y, and 21K are arranged along the transport direction D2 and are at the same position in the width direction D1. In the example of FIG. 2, the nozzle arrangement direction D3 is parallel to the width direction D1, but the nozzle arrangement direction D3 may be inclined obliquely with respect to the width direction D1. In any case, it can be said that the nozzle arrangement direction D3 intersects with the transport direction D2, and the plurality of nozzles 20 are arranged at regular or approximately regular intervals in the width direction D1 as well.

[0024] According to such a recording head 18, it can be said that a nozzle row longer than the length of one recording chip 19 in the width direction D1 is formed for each type of liquid by the n recording chips 19 as a whole. Hereinafter, the maximum range in which the recording head 18 can record in the width direction D1 is called the "maximum recording width" of the recording head 18. The length of the recording head 18 in the width direction D1 may be interpreted as the approximate maximum recording width. In addition, the range in which one recording chip 19 can record in the width direction D1 is called the "chip recording width". The maximum recording width and the chip recording width are values ​​determined by the structure of the recording head 18. In the example of FIG. 2, the medium width of the medium 30 is larger than the maximum recording width of the recording head 18, so this medium 30 has a size that can receive liquid discharged by all the nozzles 20 of the recording head 18.

[0025] The control unit 11 controls the ejection operation of the recording head 18 based on the recording data representing an image, causing the recording head 18 to eject ink onto the medium 30. As is known, the recording head 18 is provided with a driving element for each nozzle 20, and the application of a driving signal to the driving element of each nozzle 20 is controlled according to the recording data, causing each nozzle 20 to eject or not eject a dot, thereby recording an image represented by the recording data onto the medium 30. The recording data is data that specifies the ejection or non-ejection of a dot for each pixel and for each ink color. The ejection of a dot is also called dot-on, and the non-ejection of a dot is also called dot-off. The control unit 11 controls the transport unit 17 and the recording head 18 to eject ink toward the medium 30 that moves relative to the recording head 18, thereby recording an image onto the medium 30.

[0026] Although not particularly shown in FIG. 2, at the joints between the recording chips 19, the ends of the recording chips 19 may overlap in the width direction D1. The area where the ends of the recording chips 19 overlap is called an overlapping portion. With the recording head 18, one color of ink in one raster line can be recorded by one nozzle 20. The raster line is a line-shaped image having a length component in the transport direction D2, and in the state of the recording data, it is a row of pixels aligned along the transport direction D2. The raster line at the position recorded by the nozzle 20 corresponding to the overlapping portion can be recorded by sharing one color between two nozzles 20 belonging to different recording chips 19. The method of recording a raster line using the nozzle 20 corresponding to the overlapping portion is publicly known, so no particular description will be given here.

[0027] 2. TP recording and correction value generation: 3 is a flowchart showing the process of TP recording and correction value generation executed by the control unit 11 according to the program 12. The explanation of this flowchart will disclose a correction value acquisition method. The control unit 11 records the TP on the medium 30 to acquire a correction value for the ejection characteristics of each nozzle 20. The ejection characteristics of each nozzle 20 is a general term for various characteristics that affect the density of the recording result, such as the volume and shape of the dots, and the presence or absence and degree of flight curvature of the dots, and the ejection characteristics vary slightly for each nozzle 20.

[0028] In step S100, the control unit 11 acquires medium information. The medium information is information including at least the size of the medium 30. The user operates the operation reception unit 14 to input the medium information of the medium 30 set in the transport unit 17 in order to record the TP. The control unit 11 acquires the medium information input by the user. The medium information may be acquired by the control unit 11 through the communication IF 16 from an external device operated by the user. Alternatively, the size of the medium 30 may be detected as medium information by a sensor (not shown) provided in the transport unit 17, and the control unit 11 may acquire this detected medium information from the sensor.

[0029] In step S110, the TP recording control unit 12a obtains "TP recording data" which is recording data for recording a TP on the medium 30 having the size indicated by the medium information obtained in step S100. In this embodiment, it is assumed that the medium 30 used for recording the TP is a size that can be recorded using the "first chips" that are m recording chips 19 out of the n recording chips 19 that make up the recording head 18. m is a natural number, and n>m. In other words, when recording the TP, the user does not use a medium 30 whose medium width is larger than the maximum recording width of the recording head 18 as illustrated in FIG. 2, but uses a medium 30 whose medium width is smaller than the maximum recording width.

[0030] The TP recording control unit 12a determines the first chip among the n recording chips 19 according to the medium width indicated by the medium information. Since the chip recording width is known, the TP recording control unit 12a may determine, for example, m as the minimum multiple of the chip recording width required to exceed the medium width, and determine the m recording chips 19 as the first chips. Among the n recording chips 19, the recording chips 19 not used for TP recording are referred to as "second chips."

[0031] For example, it is assumed that TP recording data for maximum recording width, which is recording data for recording a TP for the maximum recording width, is generated in advance and stored in the storage unit 15. In step S110, the TP recording control unit 12a generates and acquires necessary TP recording data based on the TP recording data for maximum recording width. The necessary TP recording data is a part of the TP recording data for maximum recording width, and is recording data of a size to be provided to each nozzle 20 in the range of the first chip corresponding to the medium width indicated by the medium information.

[0032] In the first chip, the nozzles 20 in the range corresponding to the medium width are referred to as "used nozzles", meaning that they are used for recording the TP. Also, the nozzles 20 that are not used for recording the TP are referred to as "unused nozzles". The nozzles 20 in the second chip naturally fall into the category of unused nozzles. Also, even the nozzles 20 in the first chip may become unused nozzles depending on their positional relationship with the medium 30 in the width direction D1. In step S120, the TP recording control unit 12a controls the recording head 18 based on the TP recording data obtained in step S110 to record the TP on the medium 30 with the nozzles in use.

[0033] 4 shows the state in which TP40 is recorded on the medium 30 as a result of step S120, from the same perspective as FIG. 2. The medium 30 shown in FIG. 4 has a medium width smaller than the maximum recording width. In FIG. 4, the recording head 18 is simplified more than in FIG. 2, and each of the n recording chips 19, 19a, 19b, 19c, 19d, 19e, 19f, and 19g, is represented by a simple rectangle. In addition, the recording chips 19a, 19b, 19c, 19d, 19e, 19f, and 19g are represented without shifting their positions in the transport direction D2.

[0034] According to Fig. 4, the recording chips 19a and 19g at both ends of the recording head 18 correspond to the second chips, and the continuous recording chips 19b, 19c, 19d, 19e, and 19f excluding the second chips correspond to m first chips. The medium width of the medium 30 is shorter than the length of the width direction D1 including the recording chips 19b, 19c, 19d, 19e, and 19f. That is, according to Fig. 4, n = 7 and m = 5, but of course this is also only one example. And according to Fig. 4, TP40 is recorded at a position downstream of the recording head 18 on the medium 30.

[0035] Assume that TP40 is a TP recorded with one color of ink, for example, C ink. TP40 is an image in which a plurality of pattern areas 31, 32, 33, and 34 with stepwise different ink amounts are arranged in the transport direction D2. The ink amount can be regarded as the ink coverage rate per unit area of ​​the medium 30, and may also be referred to as the recording rate or duty. In the image data before being converted into recording data having binary information of dot-on or dot-off for each pixel, the ink amount can be regarded as a gradation value for each pixel expressed in 256 gradations, for example, and in the recording data, it can also be regarded as the ratio of dot-on pixels to the number of pixels. Each of the pattern areas 31, 32, 33, and 34 has a constant ink amount within one area, and in the example of FIG. 4, the pattern area 31 has the smallest ink amount, and the pattern area 34 has the largest ink amount. Needless to say, the number of pattern areas forming TP40 is not limited to four.

[0036] The length of each of the pattern areas 31, 32, 33, and 34 constituting TP40 in the width direction D1 corresponds to the range of nozzles used in the width direction D1. In other words, TP40 is recorded using nozzles used in the recording head 18 for ejecting C ink. The TP recording data obtained in step S110 is recording data for recording such TP40 in the recording head 18. Note that, if a setting is made to secure a predetermined width of margin on the edge of the medium 30, that is, to perform so-called bordered recording, the range of nozzles used in the width direction D1 is naturally narrower than the medium width in order to secure the margin. In FIG. 4, the range of nozzles used is indicated by arrows at both ends of a two-dot chain line. Also, the linear area surrounded by a dashed line in FIG. 4 indicates one raster line RL. One raster line RL can be recorded by one nozzle 20.

[0037] In step S130, the correction value generating unit 12b of the control unit 11 obtains TP read data as a result of reading the TP. That is, the TP 40 recorded on the medium 30 in step S120 is read by the reading device 1, and the TP read data as a result of the reading is transferred from the reading device 1 to the control unit 11.

[0038] In step S140, the correction value generating unit 12b generates a correction value for each nozzle 20 of the first chip based on the TP read data acquired in step S130. Since the process of generating a correction value for the nozzles in use is publicly known, step S140 will be described briefly. The correction value generating unit 12b compares the density of each raster line RL and each pattern area of ​​the TP read data with a reference value of the density of each pattern area, and sets a correction value according to the comparison result as a correction value for each raster line RL, that is, for each nozzle in use used to record the raster line RL. The density referred to here is, for example, brightness, and high density corresponds to low brightness, and low density corresponds to high brightness. The reference value of the density for each pattern area is a kind of ideal value of the density for each pattern area, and may be determined in any way, for example, by adopting an average value or a median value for each pattern area regarding the density, or by adopting a value previously stored for each pattern area.

[0039] Therefore, for a nozzle in use whose density obtained from the TP read data is higher than the reference value, the correction value generating unit 12b generates a correction value for lowering the density according to the difference between the density and the reference value. On the other hand, for a nozzle in use whose density obtained from the TP read data is lower than the reference value, the correction value generating unit 12b generates a correction value for increasing the density according to the difference between the density and the reference value. As a result of such processing, a correction value is generated for each nozzle in use, here for each nozzle in use for ejecting C ink of the recording head 18. The correction value of a nozzle 20 is data to be applied to a raster line RL recorded by the nozzle 20 in the recording data, and is applied to the ink amount for each pixel expressed in 256 gradations from 0 to 255, for example. Needless to say, the correction value of one nozzle 20 may be each correction value for each of the 256 gradations of the ink amount. Alternatively, the correction value may be data to be applied to the recording data itself having binary information for each pixel to increase or decrease the number of dots on.

[0040] As described above, the first chip may also include unused nozzles. In step S140, the correction value generating unit 12b may conveniently associate some dummy value with the unused nozzles among the nozzles 20 of the first chip as a correction value.

[0041] Since the explanation is the same, it will be omitted, but the control unit 11 naturally records the TP for each ink other than C ink, such as MYK, using the nozzles in use that correspond to the medium width, generates correction values ​​for the nozzles in use for each ink based on the TP reading data, and also executes steps S150 and S160 described below.

[0042] In step S150, the correction value generating unit 12b generates a correction value for each nozzle 20 of the second chip based on the correction value generated in step S140 for each nozzle 20 of the first chip. Step S150 will be specifically described below.

[0043] First Example: In this embodiment, the position of each nozzle 20 in the width direction D1 in the recording chip 19 is called the "nozzle position in the chip". Since all of the n recording chips 19 have the same structure, each of them has the same number of nozzles 20. Therefore, for each recording chip 19, a position number indicating the nozzle position in the chip, such as #1, #2, #3, ... #N, is assigned to each nozzle 20 in sequence from one end side to the other end side along the width direction D1, so that the nozzle position in the chip of each nozzle 20 can be grasped. In other words, if one recording chip 19 has N nozzles 20, each of the multiple recording chips 19 will have nozzles 20 with position numbers = #1 to #N.

[0044] In step S150, the correction value generating unit 12b generates the correction value of the nozzle 20 of the second chip based on the correction value of the nozzle 20 of the first chip, which has the same nozzle position in the chip as the nozzle 20. For example, the correction value of the nozzle 20 of the position number = #p of the recording chip 19c, which is one of the first chips, is set as the correction value of the nozzle 20 of the position number = #p of the recording chip 19a, which is one of the second chips. p indicates any one integer from 1 to N. Similarly, for example, the correction value of the nozzle 20 of the position number = #p of the recording chip 19e, which is one of the first chips, is set as the correction value of the nozzle 20 of the position number = #p of the recording chip 19g, which is one of the second chips. In this way, the correction value of the nozzle 20 of the first chip obtained from the TP reading data and the nozzle 20 of the nozzle 20 that has the same nozzle position in the chip as the nozzle 20 of the second chip is directly used as the correction value of the nozzle 20 of the second chip, so that the correction value can be easily generated for each nozzle 20 of the second chip.

[0045] Example 2: In step S150, the correction value generating unit 12b may generate the correction value for the nozzles 20 of the second chip by using an average value of the correction values ​​for the nozzles 20 of the first chip. For example, the correction value generating unit 12b calculates an average value of the correction values ​​of the multiple first chips generated as described above from the TP read data, and sets such average value as the correction value for each nozzle 20 of the second chip.

[0046] Alternatively, in step S150, the correction value generating unit 12b may average the correction values ​​of the nozzles 20 in the first chip that share a common nozzle position in the chip, and use this average value as the correction value of the nozzles 20 in the second chip that share a common nozzle position in the chip. Specifically, an average value is calculated from the correction values ​​of the nozzles 20 with position number = #p of each of the recording chips 19c, 19d, and 19e, and this average value is used as the correction value of the nozzles 20 with position number = #p of each of the recording chips 19a and 19g.

[0047] Additional explanation regarding steps S140 and S150: Here, the processing of steps S140 and S150 will be further explained. FIG. 5 shows a graph of the correspondence between the nozzles 20 that eject a certain ink color, for example, C ink, and the correction values. The upper part of FIG. 5 shows the correction values ​​at the time when step S140 is completed, and the lower part of FIG. 5 shows the correction values ​​at the time when step S150 is completed. The graphs shown in the upper and lower parts of FIG. 5 are read in the same way, and as an example, they show the correspondence between the nozzles 20 of each of the recording chips 19a, 19b, 19c, 19d, and 19e and the correction values. As described above, each recording chip 19 has nozzles 20 with position numbers = #1 to #N.

[0048] The vertical axis of the graph in Fig. 5 is not the correction value itself, but the ink amount after the correction value has been applied, that is, the correction ink amount, which indirectly indicates the correction value. For example, it is the correction ink amount obtained by adding the correction value for each nozzle 20 to the ink amount for C ink with a gradation value of 128. Therefore, if the correction ink amount > 128, it means that a positive correction value that increases the ink amount has been applied, and if the correction ink amount < 128, it means that a negative correction value that decreases the ink amount has been applied. Since the correction ink amount indirectly indicates the correction value, the correction ink amount is also simply referred to as the correction value in Fig. 5 and Fig. 6 described below.

[0049] As described above, in step S140, the correction value generating unit 12b generates a correction value for each nozzle 20 of the first chip. Therefore, as shown in the upper part of FIG. 5, at the time when step S140 is completed, the correction value for each nozzle 20 has not been generated for the recording chip 19a, which is the second chip. Here, the first chip that is closest to the second chip in the width direction D1 among the first chips is called the "boundary chip". According to FIG. 4, among the recording chips 19b, 19c, 19d, 19e, and 19f, which are the first chips, the recording chips 19b and 19f correspond to the boundary chips. As described above, the control unit 11 recorded TP40 on the medium 30 using the first chip including the boundary chip.

[0050] In Fig. 5, the correction value is also expressed for the boundary chip, recording chip 19b. In the upper part of Fig. 5, focusing on recording chip 19b, the range of nozzles 20 with position numbers = #1 to #N is divided into ranges X, Y, and Z from recording chip 19a side toward recording chip 19c side. Range X, which is closest to recording chip 19a, is the range of unused nozzles of recording chip 19b, and as described above, a predetermined dummy value is given as a correction value. Range Y and range Z are the ranges of used nozzles of recording chip 19b.

[0051] Although it depends on the structure and characteristics of the reading device 1 that reads the medium 30 on which the TP40 is recorded, in this embodiment, the influence of stray light, which is external light, when the TP40 is read is taken into consideration. The stray light is reflected light from the paper white portion of the medium 30 that is received by the sensor of the reading device 1. Due to the influence of stray light, the color of the edge portion of the TP40 may not be read accurately, the TP reading data may lack accuracy, and the resulting correction value may also be incorrect. Therefore, among the correction values ​​of the nozzles 20 of the first chip, the correction value corresponding to the range affected by the stray light is not adopted as it is, so that the value generated in step S140 is not adopted as it is. The range Y corresponds to the range affected by the stray light, and the size of the range Y, that is, the number of nozzles corresponding to the range Y, is determined in advance based on the structure and characteristics of the reading device 1. According to the upper part of FIG. 5, the correction value of the range Y is relatively larger than the correction value of the range Z, which indicates that the correction value of the range Y was generated based on the TP reading data affected by the stray light.

[0052] In step S150, the correction value generating unit 12b generates a correction value for the nozzle 20 of the second chip based on the correction value of the nozzle 20 of the first chip excluding the boundary chip, acquired from TP40. That is, when generating the correction value of each nozzle 20 of the recording chip 19a, which is the second chip, as described above, the correction value of the nozzle 20 of the second chip is generated using the correction value of the nozzle 20 of each first chip such as the recording chips 19c, 19d, and 19e that are not boundary chips among the first chips. However, it is possible to use a part of the correction value of the nozzle 20 of the boundary chip in generating the correction value for the second chip. The correction value generating unit 12b may generate a correction value for the nozzle 20 of the second chip using the correction value of the nozzle 20 of the boundary chip that belongs to the range Z whose correction value can be said to be not affected by stray light.

[0053] FIG. 6 illustrates the correction values ​​of the nozzles 20 of the recording chips 19a, 19b, 19c, 19d, and 19e with position numbers = #1 to #N. However, the numerical values ​​shown in FIG. 6 are not the correction values ​​themselves but the correction ink amounts as described in FIG. 5. In the graph in the lower part of FIG. 5 and FIG. 6, the correction value of the recording chip 19a, which is the second chip, is a value generated in step S150 based on the correction values ​​of the recording chips 19c, 19d, and 19e, which are the first chips, as described above. For example, as shown in the gray boxes in FIG. 6, the correction value of the nozzle 20 of the recording chip 19a with position number = #1 is the average value of the correction values ​​of the nozzles 20 of the recording chips 19c, 19d, and 19e with position number = #1. Similarly, in the graph at the bottom of Figure 5 and Figure 6, the correction value of nozzle 20 with position number = #p on recording chip 19a is set to the average of the correction values ​​of nozzle 20 with position number = #p on recording chips 19c, 19d, and 19e.

[0054] The correction values ​​of the ranges X and Y of the recording chip 19b, which are indicated by thick frames in Fig. 6, remain the correction values ​​generated in step S140, and as described above, the correction values ​​for the range X are dummy values. Also, the correction values ​​for the range Y are affected by stray light. Therefore, in step S150, the correction value generating unit 12b replaces the correction values ​​of the ranges X and Y of the recording chip 19b with the correction values ​​generated for the recording chip 19a, which is the second chip. In Fig. 6, as an example, the ranges X and Y are the ranges of position numbers #1 to #103 in terms of nozzle positions within the chip.

[0055] The correction value generating unit 12b may simply replace the correction values ​​of the position numbers = #1 to #103 of the recording chip 19b with the correction values ​​of the position numbers = #1 to #103 of the recording chip 19a, but may also perform the replacement after making the following offset: That is, the correction value generating unit 12b offsets the correction values ​​of the nozzles 20 of the second chip according to the difference between the average value of the correction values ​​of the nozzles 20 of the boundary chip and the average value of the correction values ​​of the nozzles 20 of the second chip, and replaces at least a part of the correction values ​​of the nozzles 20 of the boundary chip with the correction values ​​of the nozzles 20 of the second chip after the offset.

[0056] Such offset will be specifically described with reference to FIG. 5. The correction value generating unit 12b obtains an average value (first average value) of the correction values ​​of the nozzles 20 in the range Z of the recording chip 19b, which is the boundary chip, where it can be said that an appropriate correction value has been obtained, and further obtains an average value (second average value) of the correction values ​​of the nozzles 20 of the position numbers = #1 to #N of the recording chip 19a. Next, a difference = first average value - second average value is obtained. Then, a value obtained by adding the difference to the correction values ​​of the nozzles 20 of the position numbers = #1 to #103 corresponding to the range X, Y of the recording chip 19b among the correction values ​​of the recording chip 19a is set as a post-offset correction value, and the correction values ​​of the nozzles 20 of the range X, Y (position numbers = #1 to #103) of the recording chip 19b are replaced with this post-offset correction value. The lower part of FIG. 5 shows the correction values ​​in a state where such replacement has been completed. By performing replacement via an offset in this manner, it is possible to prevent the correction value for each nozzle 20 in the recording chip 19b from suddenly changing between the ranges X and Y and the range Z.

[0057] Alternatively, the correction value generation unit 12b may add the difference to the correction value of the nozzles 20 of the position numbers = #1 to #N of the recording chip 19a to obtain a post-offset correction value, and replace the correction value of the nozzles 20 of the position numbers = #1 to #N of the recording chip 19b with this post-offset correction value. 5 and 6, the correction value generating unit 12b also generates a correction value for the second chip, recording chip 19g, located on the opposite side to recording chip 19a in the width direction D1, based on the correction value of the nozzle 20 of the first chip. Also, for recording chip 19f, which is a boundary chip located on the opposite side to recording chip 19b in the width direction D1, the above-mentioned replacement is performed using the correction value and offset of the nozzle 20 of recording chip 19g for at least the correction values ​​of the nozzles 20 corresponding to unused nozzles and a predetermined range affected by stray light.

[0058] In step S160, the correction value generating unit 12b stores the correction value finally generated through steps S140 and S150 in a predetermined storage location such as the storage unit 15, and ends the illustrated flowchart. Thereafter, the control unit 11 performs correction using the correction value when converting image data arbitrarily selected by the user as the recording target into recording data and causing the recording head 18 to record an image based on the recording data. This suppresses uneven density in the recording result caused by variations in the ejection characteristics of each nozzle 20.

[0059] 3. Summary: Thus, according to this embodiment, the recording device 10 includes n recording chips 19 each having a plurality of nozzles 20 arranged thereon capable of discharging liquid onto a medium 30, and a control unit 11 that controls liquid discharge by the nozzles 20, and is capable of recording a TP onto the medium 30 for acquiring a correction value for the discharge characteristics of each nozzle 20 by the liquid discharge, and the n recording chips 19 are arranged at different positions along a predetermined first direction. The control unit 11 records the TP onto the medium 30 using first chips, which are m recording chips 19 out of the n recording chips 19, the number of which is less than n, and generates a correction value for the nozzles 20 of a second chip that is a recording chip 19 and was not used to record the TP, based on the correction value for the nozzles 20 of the first chip acquired from the TP.

[0060] According to the above configuration, the recording device 10 records a TP on a medium 30 using the first chips, which are m recording chips 19 out of the n recording chips 19, and generates a correction value for the nozzles 20 of the second chip that was not used to record the TP based on the correction value for the nozzles 20 of the first chip obtained from the TP. Therefore, when recording the TP, it is possible to reduce consumption of liquid such as ink and to use a medium 30 that is smaller than the size of the medium 30 that can be recorded using all the recording heads 19, which reduces costs for the user. In addition, by generating a correction value for the nozzles 20 of the second chip, when recording on a large-sized medium 30 that actually requires the use of the second chip, it is not necessary to record the TP using the second chip again, and it is possible to obtain a recording result of good image quality by applying the correction values ​​of the first chip and the second chip.

[0061] Furthermore, according to this embodiment, when the first chip among the first chips that is closest to the second chip in the first direction is determined to be the boundary chip, the control unit 11 may record a TP on the medium 30 using the first chip including the boundary chip, and generate a correction value for the nozzle 20 of the second chip based on the correction value of the nozzle 20 of the first chip excluding the boundary chip obtained from the TP. According to the above configuration, the control unit 11 generates correction values ​​for the nozzles 20 of the second chip based on the correction values ​​for the nozzles 20 of the first chip excluding the boundary chip. This makes it possible to eliminate the influence of stray light and the like when reading the TP and generate correction values ​​appropriate for each nozzle 20 of the second chip.

[0062] Furthermore, according to this embodiment, when the position of each nozzle 20 in the first direction within the recording chip 19 is defined as the nozzle position within the chip, the control unit 11 may generate a correction value for the nozzle 20 of the second chip based on the correction value for the nozzle 20 of the first chip, which has the same nozzle position within the chip as the nozzle 20 in question. According to the above configuration, the control unit 11 can easily and appropriately generate correction values ​​for each nozzle 20 in the second chip that is not used for recording the TP, under the assumption that nozzles 20 that have a common nozzle position within the chip tend to have similar ejection characteristics.

[0063] Furthermore, according to this embodiment, the control unit 11 may generate the correction value for the nozzles 20 of the second chip by using an average value of the correction values ​​for the nozzles 20 of the first chip. According to the above configuration, the control unit 11 can easily generate a correction value that is reasonably appropriate for the second chip, whose nozzles 20 have unknown ejection characteristics, by calculating the average correction value of the nozzles 20 of multiple first chips. Furthermore, the control unit 11 may generate the correction value for the nozzle 20 of the second chip by averaging the correction values ​​for the nozzles 20 of a plurality of first chips that have the same nozzle position within the chip as the nozzle 20 in question.

[0064] Furthermore, according to this embodiment, the control unit 11 may offset the correction value of the nozzle 20 of the second chip according to the difference between the average value of the correction value of the nozzle 20 of the boundary chip and the average value of the correction value of the nozzle 20 of the second chip, and replace at least a portion of the correction value of the nozzle 20 of the boundary chip with the correction value of the nozzle 20 of the second chip after offset. According to the above configuration, the control unit 11 can replace, among the correction values ​​for each nozzle 20 of the boundary chip, a correction value that is unreliable due to the influence of stray light or the like during TP reading, with a more appropriate correction value.

[0065] In the process of generating the correction value described above in this embodiment, the control unit 11 can further use a predetermined coefficient or the like to further optimize the correction value depending on the purpose.

[0066] Although only some of the combinations of claims are described in the claims, this embodiment naturally includes within its scope not only one-to-one combinations of independent claims and dependent claims, but also various combinations of multiple dependent claims. In addition to the recording device 10 and system, this embodiment discloses inventions in various categories, such as a method based on the processes or steps executed by them, and a program 12 for implementing the method in cooperation with a processor.

[0067] For example, according to a correction value acquisition method for acquiring a correction value of the ejection characteristics of each nozzle 20 in n recording chips 19 in which a plurality of nozzles 20 capable of ejecting liquid onto a medium 30 are arranged, the n recording chips 19 are arranged at different positions along a predetermined first direction, and the method includes a TP recording step of recording a TP for acquiring a correction value onto the medium 30 by liquid ejection performed by a first chip, which is m recording chips 19, the number of which is less than n, among the n recording chips 19, and a correction value generating step of generating a correction value for the nozzles 20 of a second chip of the recording chip 19 that was not used for recording the TP, based on the correction value for the nozzles 20 of the first chip acquired from the TP. According to the above embodiments, for example, steps S110 and S120 can be interpreted as corresponding to the TP recording step, and steps S140 and S150 as corresponding to the correction value generating step. [Explanation of symbols]

[0068] 10...recording device, 11...control unit, 12...program, 12a...TP recording control unit, 12b...correction value generation unit, 13...display unit, 14...operation reception unit, 15...storage unit, 16...communication IF, 17...transport unit, 18...recording head, 19, 19a, 19b, 19c, 19d, 19e, 19f, 19g...recording chip, 20...nozzle, 21C, 21M, 21Y, 21K...nozzle array, 30...medium, 31, 32, 33, 34...pattern area, 40...TP

Claims

1. n recording chips each having an array of nozzles capable of ejecting liquid onto a medium; a control unit for controlling liquid ejection from the nozzle, a recording apparatus capable of recording a test pattern on the medium by the liquid ejection to obtain a correction value of the ejection characteristics of each of the nozzles, the n recording chips are arranged at different positions along a predetermined first direction, The control unit is recording the test pattern on the medium using first chips, which are m recording chips out of the n recording chips, the number of which is less than n; A printing apparatus characterized in that the correction value of the nozzles of a second chip, which is a printing chip that was not used to print the test pattern, is generated based on the correction value of the nozzles of the first chip obtained from the test pattern.

2. When the first chip that is closest to the second chip in the first direction among the first chips is defined as a boundary chip, The control unit is recording the test pattern on the medium using the first chip including the boundary chip; 2. The printing apparatus according to claim 1, wherein the correction values ​​for the nozzles of the second chip are generated based on the correction values ​​for the nozzles of the first chip excluding the boundary chip, the correction values ​​being obtained from the test pattern.

3. When the position of each of the nozzles in the first direction in the recording chip is defined as a nozzle position in the chip, 3. The printing apparatus according to claim 1, wherein the control unit generates the correction value for the nozzle of the second chip based on the correction value for the nozzle of the first chip that has the same nozzle position in the chip as the nozzle of the second chip.

4. 3. The printing apparatus according to claim 1, wherein the control unit generates the correction value for the nozzles in the second chip by using an average value of the correction values ​​for the nozzles in a plurality of the first chips.

5. 3. The recording device according to claim 2, wherein the control unit offsets the correction value of the nozzles of the second chip according to a difference between an average value of the correction values ​​of the nozzles of the boundary chip and an average value of the correction values ​​of the nozzles of the second chip, and replaces at least a portion of the correction value of the nozzles of the boundary chip with the correction value of the nozzles of the second chip after the offset.

6. A correction value acquisition method for acquiring a correction value of an ejection characteristic of each of n nozzles arranged in a recording chip capable of ejecting liquid onto a medium, the correction value comprising: the n recording chips are arranged at different positions along a predetermined first direction, a test pattern recording step of recording a test pattern for acquiring the correction value on the medium by liquid ejection performed by first chips, which are m of the n recording chips, the m being a number less than the n; a correction value generation process for generating the correction values ​​for the nozzles of a second chip, which is the recording chip and was not used to record the test pattern, based on the correction values ​​for the nozzles of the first chip acquired from the test pattern.

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