Recording device and recording method

Abstract

To accurately correct an ink landing position when a recording head is replaced.SOLUTION: Position detection means detects a nozzle position of a first recording head mounted on a mounting part, the nozzle position detection means detects a nozzle position of a second recording head when the first recording head is removed from the mounting part and the second recording head is mounted on the mounting part, and determination means determines an adjustment position of the second recording head on the basis of a difference between the nozzle position of the first recording head and the nozzle position of the second nozzle head, and an adjustment value of the first recording head determined by the determination means.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a recording apparatus and a recording method. [Background technology]

[0002] Inkjet recording devices are known that have replaceable recording heads and that correct the ink landing position when the recording head is replaced. However, correcting the ink landing position takes time, so correcting the ink landing position every time the recording head is replaced places a heavy burden on the user.

[0003] Patent Document 1 discloses a method for adjusting the ink landing position after replacing a printhead using information about the ink landing position that is written to the printhead in advance. Factors that cause deviations in the ink landing position include those specific to the printing device and those specific to the printhead. The ink landing position is corrected by printing an adjustment pattern on the printhead at the time of delivery. The ink landing position correction value at this time is equal to the sum of the printing device-specific correction value and the printhead-specific correction value. The printing device-specific correction value is calculated by taking the difference between the ink landing position correction value and the printhead-specific correction value. Subsequently, when the printhead is replaced, the ink landing position correction value is updated by taking the sum of the correction value specific to the installed printhead and the correction value specific to the printhead. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-5661 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method of Patent Document 1 requires that parameters that cause deviations in the ink landing position for each print head be measured and recorded in advance. Furthermore, if the position at which the print head is fixed shifts when the print head is installed, the shift cannot be corrected. Therefore, there is a risk that the accuracy of the correction of the ink landing position will be insufficient.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to accurately correct the ink landing position when replacing a recording head. [Means for solving the problem]

[0007] The present invention is a recording device comprising: an attachment section to which a recording head having nozzles for ejecting ink is detachably attached; a moving means for moving the recording head in a movement direction; a nozzle position detection means for acquiring the position of the nozzles of the recording head; and a determination means for determining a correction value for correcting the landing position of ink ejected from the recording head, wherein the position detection means detects the nozzle position of a first recording head attached to the attachment section, and the nozzle position detection means detects the nozzle position of the second recording head when the first recording head is removed from the attachment section and a second recording head is attached to the attachment section, and the determination means determines the adjustment value of the second recording head based on the difference between the nozzle position of the first recording head and the nozzle position of the second nozzle head and the adjustment value of the first recording head determined by the determination means. [Effects of the Invention]

[0008] According to the present invention, the ink landing position can be corrected with high precision when replacing the print head. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the appearance of a recording apparatus according to a first embodiment. [Figure 2]FIG. 1 is a perspective view showing the internal configuration of a recording apparatus according to a first embodiment. [Figure 3] FIG. 2 is a block diagram showing the control configuration of the recording apparatus according to the first embodiment. [Figure 4] 1 is a flowchart of the first embodiment. [Figure 5] FIG. 10 is a diagram showing the carriage position when detecting the nozzle position. [Figure 6] FIG. 2 is a schematic top view of the main part of the recording apparatus. [Figure 7] FIG. 10 is a diagram showing an output when the droplet detection sensor detects the nozzle position. [Figure 8] FIG. 10 is a diagram illustrating correction of the writing start position. [Figure 9] FIG. 10 is a diagram showing a state when an adjustment pattern is printed. [Figure 10] 10A and 10B are diagrams illustrating outputs when a density sensor detects an adjustment pattern. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention. Note that the same components will be described with the same reference numerals. Furthermore, the relative arrangements, shapes, etc. of the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention to only those.

[0011] In the following description of the embodiments, "recording" not only refers to the formation of significant information such as characters and figures, but also broadly includes the formation of images, designs, patterns, etc. on a sheet. In this embodiment, a roll sheet is assumed as the sheet, but cut paper, cloth, plastic film, etc. may also be used. Furthermore, "ink" should be broadly interpreted and refers to a liquid that can be applied to a sheet to form images, designs, patterns, etc., or to process the sheet, or to be used for ink processing.

[0012] <Inkjet recording device> The inkjet printing apparatus of this embodiment will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view of the printing apparatus 101. Fig. 2 is a perspective view of the main parts of the printing apparatus 101. Fig. 3 is a configuration diagram of the control system of the printing apparatus 101.

[0013] The recording device 101 holds a rolled sheet R, which is a sheet S wound in a roll shape, on the back side of the device by a spool 201. The sheet S is wound around a core, and the core is fixed to the spool 201 at both ends in the sheet width direction. Although the sheet S is held on the back side here, the rolled sheet R may also be held on the front side of the device. The spool 201 is rotatably held in the recording device 101 by a holding unit of the recording device 101 and rotated by a roll drive motor 303. When the spool 201 rotates, the sheet S is supplied from the rolled sheet R to a conveying roller 205. The conveying roller 205 rotates while sandwiching the sheet S, and conveys the sheet S to a position where the recording head 206 can record on the sheet S. The recording head 206 is disposed downstream of the conveying roller 205 in the conveying direction of the sheet S. The recording head 206 is detachable from a carriage 207, which is an attachment unit. An image is recorded by ejecting ink onto the sheet S conveyed from the recording head 206 while the carriage 207 moves in the X direction. The sheet S with the recorded image is discharged from a discharge section located downstream of the recording head 206 in the conveyance direction.

[0014] The operation panel 102 is an interface module that accepts various operations from the user. The user can use various switches and the like provided on the operation panel 102 to make various settings for the recording device 101. Examples of the various settings for the recording device 101 include settings for the size and type of sheet S. In addition, if the recording head 206 breaks down and images can no longer be recorded properly, the user can select replacement of the recording head 206 from the operation panel 102 and replace the recording head 206 by following the instructions displayed on the operation panel 102.

[0015] A sheet detection sensor 302 is disposed between the holder and the conveying rollers 205. When the sheet detection sensor 302 detects that a user has supplied a sheet S from the roll sheet R, the conveying operation of the sheet S is initiated. The conveying of the sheet S is performed by synchronizing the conveying rollers 205 and the spool 201. To record an image on the sheet S, first, a conveying operation is performed to convey the sheet S to a position facing the recording head 206. Next, a recording operation is performed to scan the recording head 206 in a direction intersecting (orthogonal to) the conveying direction of the sheet S while ejecting ink. The desired image is recorded on the sheet S by alternately performing the conveying operation of the sheet S and the image recording operation. The sheet S on which the image has been recorded is sequentially conveyed downstream of the recording head 206 in the conveying direction. The conveyed sheet S is cut by a cutter provided in the discharge section. The cut sheet S is stacked in the basket 103.

[0016] 3 is a block diagram showing the configuration of a control system provided in the recording apparatus 101. A motor control unit 307 controls a roll drive motor 303, a conveyance roller drive motor 304, a carriage drive motor 204, a lift drive motor 305, and a cutter drive motor 306 in accordance with a control program recorded in a memory 312. The conveyance roller drive motor 304 rotates the conveyance roller 205, and the roll drive motor 303 rotates the spool 201. The conveyance roller drive motor 304 is provided with an encoder 203 that detects the amount of rotation to detect the amount of conveyance of the sheet S. The carriage drive motor 204 rotates a carriage belt 202, thereby moving a carriage 207 and a recording head 206 mounted thereon.

[0017] Various setting information and the like based on user operations from the operation panel 102 or an external PC connected to a USB port 313 is input to the CPU 309 via an input IF 311. The input information is stored in a memory 312. The CPU 309 can read out the information stored in the memory 312 as needed and perform various processes on the read out information. That is, the CPU 309 includes a processing unit that executes various processes.

[0018] The CPU 309 controls the carriage encoder 301, the density sensor 210, the droplet detection sensor 208, and the sheet detection sensor 302 via the sensor control unit 308 to obtain information. Various controls are performed based on inputs from the carriage encoder 301, the density sensor 210, the droplet detection sensor 208, and the sheet detection sensor 302.

[0019] The user sets the type of sheet S and the like using the operation panel 102. Therefore, the CPU 309 can execute various controls using correction values, conversion tables, and the like stored in the memory 312. For example, the CPU 312 calculates an optimal correction value for the ink landing position based on the difference in nozzle position before and after replacement of the print head 206, a correction value for the ink landing position that was previously stored, and the set information for the sheet S. As a result, the CPU 309 sets the correction value for the ink landing position in the head control unit 310, thereby achieving highly accurate image recording.

[0020] <Correction of ink landing position when replacing a recording head> A flowchart for correcting the ink landing position of the recording device 101 when replacing the recording head 206 is shown in Fig. 4. The processing in Fig. 4 is executed by the CPU 309 controlling each control unit in accordance with a program stored in the memory 312. The following explanation will also use Figs. 5 and 6.

[0021] In step S101, the CPU 309 controls the carriage drive motor 204 via the motor control unit 308. Figure 5 shows the carriage position during nozzle detection. By continuously driving the carriage drive motor 204, the carriage 207 moves from the position shown in Figure 5(a) to the position shown in Figure 5(b). Figure 5(a) is the start position of nozzle position detection, and the carriage position at this time is referred to as carriage position C1. Figure 5(b) is the end position of nozzle position detection, and the carriage position at this time is referred to as carriage position C2.

[0022] FIG. 6 is a schematic diagram of the main components of the print head 206, the sheet S, and the droplet detection sensor 208, seen through from the top surface (+Z direction) of the printing apparatus. The print head 206 has multiple nozzle rows arranged in the X direction, with the nozzles aligned in the Y direction. The designated nozzle 603 is the single nozzle at the most downstream position in the nozzle row that is closest to the density sensor 210. While the carriage 207 is moving, the CPU 309 controls the print head 206 via the head control unit 310 to continuously eject ink from the designated nozzle 603 in FIG. 6. The CPU 309 obtains the output value of the droplet detection sensor 208, as shown in FIG. 7, via the sensor control unit 308. The droplet detection sensor 208 receives light emitted from the light-emitting element 605 with the light-receiving element 604. When ink is present near the optical axis 606, it outputs a signal corresponding to the amount of ink. The vertical axis of the graph in FIG. 7 represents the output of the droplet detection sensor 208, and the horizontal axis represents the carriage position. The carriage position is calculated from the output value of the carriage encoder 301, with carriage position C1 as the reference. At the carriage position of the carriage 207 corresponding to the center between the rising and falling edges of the graph in FIG. 7, the designated nozzle 603 is located directly above the droplet detection sensor 208. The position of the carriage 207 at this time is calculated from the output value of the carriage encoder 301. When the position of the designated nozzle 603 of the print head 206 attached to the carriage 207 changes, the position of the carriage when the designated nozzle 603 is located directly above the droplet detection sensor 208 also changes equally. In other words, the change in nozzle position and the change in carriage position are equal. Therefore, in this embodiment, the position of the carriage when the designated nozzle 603 is located directly above the droplet detection sensor 208 is defined as the nozzle position. The nozzle position in the graph in FIG. 7 is defined as nozzle position n2.

[0023] In step S102, the CPU 309 records the nozzle position n2 in the memory 312.

[0024] In step S103, the CPU 309 retrieves nozzle position n1 and nozzle position n2 from memory 312. Nozzle position n1 is the nozzle position of the print head 206 before replacement. Furthermore, the difference between n2 and n1 is taken to calculate the difference d1 between the nozzle positions before and after replacement. When the nozzle position difference d1 is positive, the nozzle positions of the installed print head 206 are shifted toward the density sensor 210 relative to the nozzle positions of the print head 206 before replacement. When the nozzle position difference d1 is negative, the nozzle positions are shifted away from the density sensor 210 relative to the nozzle positions of the print head 206 before replacement.

[0025] In step S104, the CPU 309 records the nozzle position difference d1 in the memory 312. The nozzle position difference d1 is the difference in the position of the same nozzle at the same carriage position after replacing the print head 206. Therefore, it is possible to cope with a case where the position at which the print head 206 is fixed shifts when the same print head 206 is detached.

[0026] In step S105, the CPU 309 retrieves from the memory 312 the correction value p1 for the ink landing position of the print head 206 in the past and the difference d1 in the nozzle position. Furthermore, the CPU 309 calculates the sum of the correction value p1 and the difference d1 to calculate the correction value p2 for the ink landing position of the currently installed print head 206. Calculation of the correction value for the ink landing position will be described in detail later. The CPU 309 sets the calculated correction value p2 for the ink landing position in the head control unit 310. This enables highly accurate image recording.

[0027] In step S106, the CPU 309 records the ink landing position correction value p2 in the memory 312.

[0028] In step S107, the CPU 309 records the nozzle position n2 as the nozzle position n1 in the memory 312. The nozzle position n1 is the nozzle position of the print head 206 before replacement, and is called up when the print head 206 is next replaced. The nozzle position n1 also records the nozzle position of the print head 206 installed at the time of shipping inspection as the initial value. Therefore, the nozzle position n1 is already set when the printing apparatus 101 arrives. The nozzle position at this time is obtained in the same way as in step S101.

[0029] In step S108, the CPU 309 records the ink landing position correction value p2 as the ink landing position correction value p1 in the memory 312. The ink landing position correction value p1 is the ink landing position correction value of the print head 206 before replacement and is called up when the print head 206 is next replaced. The correction value p1 also records the ink landing position correction value of the print head 206 at the time of shipping inspection as the initial value. Therefore, the correction value p1 is already set when the printing apparatus 101 arrives. The correction value p1 at this time is obtained by printing an adjustment pattern with the print head 206 and detecting it with the density sensor 210. The adjustment pattern is an array of patches corresponding to multiple ink landing position correction values. The density sensor 210 reads each patch, and the ink landing position correction value corresponding to the patch with the optimal output result is recorded as p1 in the memory 312.

[0030] <Calculation of correction value for ink landing position based on difference in nozzle position> There are various types of correction values ​​for the ink landing position. Here, we will explain how to correct the writing start position. The writing start position is an important parameter for borderless printing. Borderless printing involves recording an image without margins along the edge of the sheet S. The density sensor 210 detects the light intensity when light emitted from the light-emitting element 601 is reflected off the detection area and enters the light-receiving element 602. The output value changes depending on the color density. By using the density sensor 210 to detect the difference in density between the platen 209 and the sheet S, both ends of the sheet S can be detected. In this embodiment, the platen 209 is black and the sheet S is white. The sheet S may be any color other than white as long as it is not exactly the same color as the platen 209. The carriage position at which image recording begins aligned with the edge of the sheet S is called the writing start position. Replacing the print head 206 changes the position of the designated nozzle 603 at the same carriage position. As shown in Figure 8, the ink landing position also shifts by the amount of nozzle position shift. If the landing position is shifted, a blank space will be created at one end of the sheet S, and the image will be cut off at the other end.

[0031] In step S105, the CPU 309 retrieves from memory 312 the correction value p1 for the previous ink landing position of the print head 206 and the difference d1 in the nozzle position. By shifting the write start position by the difference d1 from the nozzle position of the previously used print head 206, correct borderless printing can be performed. Therefore, by taking the sum of the correction value p1 for the previously used print head 206 and the difference d1, the correction value p2 for the ink landing position of the currently installed print head 206 is determined.

[0032] In step S101, ink is continuously ejected only from the designated nozzle 603, but this is not a limitation and any nozzle on the print head 206 may be used. Ink may also be ejected from multiple nozzles. When multiple nozzles are used, an average value may be taken as the position of one nozzle. Alternatively, the position corresponding to each nozzle may be obtained, and a correction value for the ink landing position corresponding to each nozzle may finally be calculated.

[0033] Furthermore, in step S103, the correction value for the ink landing position is calculated by adding the nozzle position difference d1, but this is not limited to this, and calculations can also be performed by subtraction, multiplication by a weighted coefficient, or calculations using a table.

[0034] Furthermore, in step S105, the writing start position has been described as an example of correcting the ink landing position, but the present invention is not limited to this, and correction values ​​for any ink landing position can be similarly corrected from the nozzle position difference d1.

[0035] Also, in step S107, the nozzle position of the print head 206 at the time of shipping inspection is recorded as the initial value of the nozzle position n1, but this is not limited to this, and it may also be the average value of the nozzle positions of print heads 206 circulating on the market.

[0036] Furthermore, in step S108, the correction value of the ink landing position of the recording head 206 at the time of shipping inspection is recorded as the initial value of the correction value p1 of the ink landing position, but this is not limited to this, and it may also be the average value of the correction values ​​of the ink landing position of recording heads 206 distributed on the market, for example.

[0037] As described above, the nozzle positions before and after replacing the print head 206 are compared, and the difference between the nozzle positions and the correction value for the ink landing position before replacing the print head are used to calculate the correction value for the ink landing position after replacing the print head. By doing this, it is possible to print highly accurate images without printing adjustment patterns.

[0038] (Second embodiment) <High-precision nozzle position detection> In the first embodiment, when the nozzle positions of the print head 206 are detected in step S101 of Fig. 4, ink is ejected while the carriage drive motor 204 is being driven. Therefore, ink is ejected while the carriage 207 is moving. As shown in Fig. 9, when ink is ejected while the carriage 207 is moving, the ink is ejected in the direction of a resultant vector 902 of a carriage velocity vector 901 and an ink ejection velocity vector 903. At this time, if there is variation in the carriage velocity or ink ejection speed, the detected nozzle positions will also vary.

[0039] In this embodiment, ink is ejected when the carriage 207 is stopped, making it possible to detect the nozzle position without being affected by the carriage speed and ink ejection speed. To achieve this, the carriage 207 is repeatedly moved slightly and stopped by intermittently driving the carriage drive motor 204. Ink is ejected only when the carriage 207 is stopped. The smaller the amount of carriage movement when the carriage drive motor 204 is intermittently driven, the more accurately the nozzle position can be detected.

[0040] However, if the carriage movement amount during intermittent driving of the carriage drive motor 204 is small, the time required to move the carriage 207 from carriage position C1 to C2, i.e., the nozzle position detection time, becomes very long. Therefore, as in the first embodiment, the carriage drive motor 204 is first continuously driven to detect nozzle position n2. Next, in the vicinity of the detected nozzle position, the nozzle position is detected with high precision by repeatedly moving slightly and stopping, and ejecting ink when stopped, and the nozzle position n2 is updated. In this way, by limiting the range of movement of the carriage position when performing high-precision nozzle position detection, it is possible to suppress an increase in the nozzle position detection time.

[0041] As described above, by stopping the carriage 207 before ejecting ink during nozzle position detection, it is possible to perform highly accurate nozzle position detection that is not dependent on the carriage speed or ink ejection speed. Furthermore, by limiting the range in which highly accurate nozzle position detection is performed using the results of nozzle position detection performed while continuously driving the carriage 207, it is possible to prevent an increase in the time required for highly accurate nozzle position detection.

[0042] (Third embodiment) <Nozzle position detection taking nozzle misalignment into account> Consider a case where the nozzles of the print head 206 are not formed in a straight downward direction when they are generated. Even if ink is ejected while the carriage is stopped, the ink will be ejected at an angle from a deviated nozzle 1001, as shown in Figure 10. In this case, the detection results will vary depending on the distance from the optical axis 606 of the droplet detection sensor 208 to the nozzle. Figure 10 shows optical axis 1003 when the distance from the optical axis 606 to the nozzle is short, and optical axis 1004 when the distance is long. There is no deviation in the carriage movement direction between droplet detection positions 1005 and 1006 of a non-deviated nozzle 1002, but there is a deviation between droplet detection positions 1007 and 1008 of a deviated nozzle 1001.

[0043] Therefore, the height of the carriage 207 is changed in multiple steps by the lift drive motor 305, and the nozzle position is detected at each height. When the carriage height is x and the nozzle position is y, a linear function y = ax + b can be calculated. This makes it possible to obtain the nozzle position according to the carriage height.

[0044] As described above, by detecting the nozzle position while changing the height of the carriage 207 in multiple stages, it is possible to detect the nozzle position while taking into consideration the deviation of the nozzle. [Explanation of symbols]

[0045] 101 Recording device 202 Carriage Belt 203 Encoder 204 Carriage drive motor 206 Recording head 207 Carriage 208 Droplet Detection Sensor 309 CPU

Claims

1. a mounting portion to which a recording head having nozzles for ejecting ink is detachably mounted; a moving means for moving the recording head in a moving direction; a nozzle position detection means for acquiring the nozzle positions of the recording head; a determination unit for determining a correction value for correcting the landing position of ink ejected from the recording head; A recording device comprising: the nozzle position detecting means detects the nozzle position of the first recording head attached to the attachment portion, the nozzle position detecting means detects the nozzle position of the second recording head when the first recording head is removed from the mounting portion and the second recording head is mounted to the mounting portion; a determination unit that determines a correction value for the second print head based on a difference between the nozzle positions of the first print head and the nozzle positions of the second print head and the correction value for the first print head determined by the determination unit;

2. the recording head has a nozzle row in which a plurality of nozzles are arranged in a direction intersecting the movement direction, 2. The printing apparatus according to claim 1, wherein the nozzle position detection means acquires and averages the positions of a plurality of nozzles in the same nozzle row of the print head as the nozzle position used by the determination means.

3. a droplet detection means for detecting ink ejected from the recording head; and a position detection means for detecting the position of the moving means, 3. The recording apparatus according to claim 1, wherein the nozzle position detection means acquires the nozzle position based on the detection result of the droplet detection means and the detection result of the position detection means.

4. 4. A recording device according to claim 1, wherein the nozzle position detection means acquires a nozzle position based on ink ejected while the recording head is moving, and then acquires the nozzle position used by the determination means based on ink ejected while the recording head is stopped in the vicinity of the acquired nozzle position.

5. Further, the recording head has a height adjusting means for adjusting the height of the recording head. The recording device according to any one of claims 1 to 4, characterized in that the nozzle position detection means changes the height of the recording head in multiple stages by the change, detects the nozzle position at each stage, and uses the results to obtain the nozzle position that linearly corresponds to the height of the recording head.

6. a mounting portion to which a recording head having nozzles for ejecting ink is detachably mounted; a moving means for moving the recording head in a moving direction; a nozzle position detection means for acquiring the nozzle positions of the recording head; a determination unit for determining a correction value for correcting the landing position of ink ejected from the recording head; A recording method for a recording device comprising: the nozzle position detecting means detects the nozzle position of the first recording head attached to the attachment portion, the nozzle position detecting means detects the nozzle position of the second recording head when the first recording head is removed from the mounting portion and the second recording head is mounted to the mounting portion; the determining means determines a correction value for the second print head based on a difference between the nozzle positions of the first print head and the nozzle positions of the second print head and the correction value for the first print head determined by the determining means; a correction value for the second printhead that is determined, and a timing for ejecting ink from the second printhead is controlled using the correction value;

Images