Method for determining working gap, and recording device

A method for determining a working gap includes a first recording step for ejecting ink from a recording head onto a first recording medium to record a test pattern, a first imaging step for capturing the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, a function calculating step, a second recording step for recording the test pattern on a second recording medium, a second imaging step for capturing the test pattern recorded on the second recording medium, and a working gap determining step for determining, based on the number of pixels of the captured test pattern and a function, a distance between the recording head and the second recording medium.

The present application is based on, and claims priority from JP Application Serial Number 2019-015332, filed Jan. 31, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a method for determining a working gap, and a recording device.

2. Related Art

In related art, a recording device is known that records an image on a recording medium by ejecting ink onto the recording medium from a recording head provided with nozzles. For example, in JP-A-2013-233708, an inkjet recording device is disclosed as a recording device in which it is possible to adjust a distance between a recording head and a support surface that supports a recording medium.

However, in the recording device disclosed in JP-A-2013-233708, a working gap, which is a distance between the recording head and the recording medium, can be calculated in relation to the recording medium having a known medium thickness, but there is a problem that the working gap cannot be calculated in relation to the recording medium for which the thickness of the medium is unknown.

SUMMARY

A method for determining a working gap of the present application includes a first recording step for ejecting ink from a recording head onto a first recording medium having a known medium thickness to record a test pattern, a first imaging step for capturing the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, a function calculating step for calculating, based on the number of pixels of the test pattern captured at the first distance and the number of pixels of the test pattern captured at the second distance, a function to determine the distance based on the number of pixels of the captured test pattern, a second recording step for recording the test pattern on a second recording medium, a second imaging step for capturing the test pattern recorded on the second recording medium, and a working gap determining step for determining, based on the number of pixels of the captured test pattern and the function, a distance between the recording head and the second recording medium.

In the above-described method for determining the working gap, preferably, the test pattern is a pattern that is recorded by relative movement, along a first axis, of the recording head and one of the first recording medium and the second recording medium, and is used for adjusting a recording position along the first axis.

In the above-described method for determining the working gap, preferably, the first distance is a lower limit of the distance between the recording head and the first recording medium, and the second distance is an upper limit of the distance between the recording head and the first recording medium.

In the above-described method for determining the working gap, preferably, at the first distance of the first imaging step, the test pattern is enlarged or reduced to a predetermined size.

In the above-described method for determining the working gap, preferably the recording head includes a first recording head and a second recording head, in the second recording step, the test pattern is recorded, by the first recording head, onto the second recording medium, in the second imaging step, the test pattern recorded on the second recording medium is captured, and in the working gap determining step, a distance between the first recording head and the second recording medium is determined based on the number of pixels of the captured test pattern and the function, and a distance between the second recording head and the second recording medium is determined based on the distance between the first recording head and the second recording medium and the function for the second recording head.

A recording device of the present application includes a recording head configured to record a test pattern, a gap adjustment unit configured to adjust a height of the recording head, an imaging unit configured to capture the test pattern, and a control unit. The control unit records the test pattern on a first recording medium having a known medium thickness, captures the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, calculates, based on the number of pixels of the test pattern captured at the first distance and the number of pixels of the test pattern captured at the second distance, a function to determine the distance based on the number of pixels of the captured test pattern, records the test pattern on a second recording medium, captures the test pattern recorded on the second recording medium, and determines, based on the number of pixels of the captured test pattern and the function, a working gap that is a distance between the recording head and the second recording medium.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that in the drawings, apart fromFIG. 2,FIG. 3, andFIG. 8, for convenience of explanation, an X-axis, a Y-axis, and a Z-axis are illustrated as three axes orthogonal to one another. A leading end side of an arrow illustrating each of the axes is defined as a “positive side”, and a base end side is defined as a “negative side”. Additionally, in line with a direction of gravity, the positive side of the Z-axis is referred to as an “upper side” and the negative side of the Z-axis is referred to as a “lower side”. The X-axis corresponds to a first axis, and is also referred to as a main scanning direction. The Y-axis is also referred to as a transport direction. Further, a positional relationship along the transport direction of a recording medium W is also referred to as “upstream” or “downstream”.

FIG. 1is a schematic cross-sectional view illustrating an outline overall configuration of a recording device according to an embodiment. First, the outline configuration of a recording device1according to the embodiment will be described with reference toFIG. 1. Note that, in the embodiment, the recording device1is exemplified that is used for performing textile printing on the recording medium W by supplying the long recording medium W, such as a fabric, in a roll-to-roll manner, and recording images and the like using an inkjet method.

As illustrated inFIG. 1, the recording device1is provided with a feeding portion2that feeds out and transfers the recording medium W, a medium transport unit12that transports the recording medium W in the transport direction, a recording unit5that performs recording on the recording medium W in cooperation with the medium transport unit12, a winding portion6that retrieves the recording medium W, and a cleaning unit65. Then, the recording device1includes a control unit7that performs overall control of each of these components.

First, a path of the recording medium W from the feeding portion2to the winding portion6will be described.

The feeding portion2is mounted on a feeding frame17provided upstream of the medium transport unit12in the transport direction of the recording medium W. The feeding portion2includes a feeding unit18that holds the band-like recording medium W wound in a roll shape and feeds out the recording medium W to the medium transport unit12, and a slack-eliminating unit19that eliminates slack in the fed out recording medium W. For example, a fabric such as cotton, wool, polyester, or the like is used as the recording medium W.

The medium transport unit12supplies the recording medium W fed out from the feeding portion2to the recording unit5. The medium transport unit12is supported by a pair of side frames62having a flat surface formed by a Y-axis and a Z-axis, the side frames62being fixed on a main body platform11configured by assembling steel materials. The medium transport unit12includes a driving roller81positioned downstream in the transport direction, a driven roller82positioned upstream in the transport direction, and a transporting belt64that is stretched between the driving roller81and the driven roller82. The driving roller81and the driven roller82have an axis along the X-axis and are rotatably supported on the pair of side frames62via a dedicated bearing. A transport motor86is coupled to a first axial end of the driving roller81, as a power source for intermittently moving the transporting belt64.

The transporting belt64is formed in an endless shape by coupling both ends of a band-like belt, which is wider than the width of the recording medium W. A top surface of the transporting belt64is provided with an adhesive layer onto which the recording medium W is adhered. The transporting belt64is held between the driving roller81and the driven roller82, in a state in which a predetermined tension acts thereon. A press roller66, which presses the recording medium W supplied from the feeding portion2and overlaid on the transporting belt64so as to adhere the recording medium W to the transporting belt64, is provided corresponding to an upstream section of the transporting belt64. When the transport motor86is driven, the transporting belt64transports the recording medium W adhered to the transporting belting64by the press roller66in the transport direction. In this way, images and the like can be recorded on the fabric that has elasticity. After being subject to the recording by the recording unit5, the recording medium W is transported in the transport direction, is separated from the transporting belt64by a separating roller67provided downstream of the medium transport unit12, and is relayed to the winding portion6. Note that in the above description, the transporting belt64is provided with the adhesive layer to which the recording medium W is adhered, but the transporting belt64is not limited to this example. For example, the transporting belt may be an electrostatic attraction-type belt that attracts the recording medium W using static electricity.

The winding portion6is installed on a winding unit platform24provided downstream of the medium transport unit12in the transport direction of the recording medium W. The winding portion6includes a winding unit21for winding and retrieving the recorded recording medium W onto a core member in a roll shape. Further, the winding portion6includes a heater unit23that, before the recording medium W is wound, vaporizes a solvent of the ink that has permeated into the recording medium W, and a slip sheet unit22that supplies a slip sheet P to the back surface of the recording medium W being supplied to the heater unit23. The winding portion6is provided with a tension roller25that presses the back surface of the recording medium W hanging down from the heater unit23under its own weight, and that applies tension to the recording medium W being wound by the winding unit21. The winding unit21is provided with a winding motor (not illustrated) that supplies rotary power to the core member. In this way, the belt-like recording medium W on which the images and the like are recorded can be wound onto the winding unit21.

Next, the recording unit5will be described.

The recording unit5is disposed higher than the medium transport unit12. The recording unit5includes a head moving unit16, a carriage14that is caused to reciprocate, by the head moving unit16, in the main scanning direction that is a width direction of the recording medium W intersecting the transport direction, a recording head15mounted on the carriage14, and a printer cover102covering the head moving unit16, the carriage14, and the recording head15.

The head moving unit16is formed in a beam shape, and is provided between a pair of recording unit support portions211that are provided standing vertically on the outer side of the transporting belt64along the X-axis (seeFIG. 4). The head moving unit16is provided with two carriage guides111that slidably support the carriage14along the main scanning direction, and a carriage motor (not illustrated) as a power source that causes the carriage14to reciprocate along the carriage guides111. As a result of the driving of the carriage motor, the recording head15is guided by the carriage guides111along with the carriage14, and reciprocates in the main scanning direction.

The recording head15includes nozzle rows corresponding to a plurality of colors for color recording, and inks of each of the colors are supplied from ink tanks (not illustrated). A platen84that supports the recording medium W placed on the transporting belt64is provided at a position facing the recording head15. The recording head15ejects ink from each of the nozzle rows toward the recording medium W on the platen84. Further, an imaging unit50that captures the image or the like recorded on the recording medium W is provided on a downstream surface of the carriage14. The imaging unit50includes a lens, and an imaging element (not illustrated) that converts light entering from the lens into an electrical signal. The imaging unit50of the embodiment is provided with a zoom lens51(seeFIG. 4), which is a lens capable of changing an imaging range52(seeFIG. 5) by varying the focal length.

A gap adjustment unit220is provided between the head moving unit16and the recording unit support unit211supported by the main body platform11. The gap adjustment unit220expands and contracts along the Z-axis, and adjusts the height of the recording head15by raising and lowering the entire recording unit5with respect to the medium transport unit12provided on the main body platform11, that is, with respect to the transporting belt64. As a result, a working gap, which is a distance between a nozzle surface of the recording head15and the recording medium W placed on the transporting belt64, can be adjusted. For example, a mechanism including a combination of a ball screw and a ball nut, a linear guide mechanism, or the like may be employed as the gap adjustment unit220. Note that the configuration of the gap adjustment unit220described in the embodiment is an example, and a configuration may be adopted in which a gap adjustment unit using a cam mechanism or the like is incorporated into a carriage.

Note that in the embodiment, the recording head15is exemplified as being a so-called serial recording head type that is mounted on the reciprocating carriage14and ejects the ink while moving along the main scanning direction. However, the recording head15may be a so-called line recording head type in which recording heads are fixedly arranged so as to extend in the width direction of the recording medium W.

The cleaning unit65is provided below the medium transport unit12. The recording medium W is separated, and the cleaning unit65cleans, from below, the top surface of the transporting belt64moving from the driving roller81to the driven roller82. The cleaning unit65includes a rotating brush97that is driven to rotate while in contact with the transporting belt64, and removes ink, fabric fibers, or the like adhered to the top surface of the transporting belt64.

Further, a maintenance unit (not illustrated) is provided at one end in the width direction along the X-axis of the transporting belt64. In plan view from the positive side of the Z-axis, the maintenance unit is provided at a position overlapping with the recording head15that reciprocates along the X-axis. The maintenance unit includes a suction portion that sucks ink from the nozzles of the recording head15, a wiping portion that performs wiping to remove the ink adhered to the nozzle surface of the recording head15, a flushing portion that performs flushing to eject the ink from the nozzles of the recording head15, and the like.

Next, an electrical configuration of the recording device1will be described with reference toFIG. 2.FIG. 2is a block diagram illustrating electrical coupling of the recording device.

The recording device1records images and the like on the recording medium W based on recorded data input from an input device10. The input device10may be a personal computer or the like, and may have a configuration in which it is provided in the same housing as the recording device1. The input device10controls jobs causing the recording device1to perform the recording, and controls the recording device1in coordination with the control unit7of the recording device1. Software operated by the input device10includes general image processing application software for handling image data and printer driver software for generating recording data that causes the recording device1to perform the recording.

The recording device1includes the control unit7that controls each of the units and portions provided in the recording device1. The control unit7includes an interface unit (I/F)72, a CPU73, a control circuit74, a storage unit75, and the like. The interface unit72, the storage unit75, and the control circuit74are electrically coupled to the CPU73via a bus.

The interface unit72is configured to transmit and receive data between the input device10, which handles input signals and images, and the control unit7. For example, the interface unit72receives recording data and the like generated by the input device10.

The CPU73is an arithmetic processing device for performing various types of input signal processing, and overall control of the recording device1in accordance with a program stored in the storage unit75and the recording data received from the input device10. The CPU73determines the working gap, which is the distance between the recording head15and the recording medium W, and which will be described later.

The storage unit75, which serves as a storage medium that secures a program storage region, a working region, and the like of the CPU73, includes a storage element, such as a Random Access Memory (RAM), an Electrically Erasable Programmable Read Only Memory (EEPROM), or the like.

The control circuit74is electrically coupled to the recording head15, the head moving unit16, the transport motor86that rotates the drive roller81, and the like. The control circuit74generates control signals for controlling the recording head15, the head moving unit16, the transport motor86, and the like, based on the recording data and calculation results of the CPU73.

Further, the control circuit74is electrically coupled to the gap adjustment unit220. The control circuit74generates control signals for extending and contracting the gap adjustment unit220, based on a height of the recording head15input to the input device10.

Further, the control circuit74is electrically coupled to the imaging unit50. The imaging unit50is electrically coupled to the CPU73via a bus. The control circuit74generates control signals for controlling the imaging unit50. Based on the control signals generated by the control circuit74, the imaging unit50captures a test pattern53recorded on a first recording medium W1or a second recording medium W2to be described later, converts the captured test pattern53into an electrical signal, and transmits the electrical signal to the CPU73.

Based on control signals output from the control circuit74, the control unit7records a raster line of dots aligned along the X-axis, by performing main scanning, in which the carriage14is moved along the X-axis that is the main scanning direction while ejecting the ink from the nozzle rows. Further, based on control signals output from the control circuit74, the control unit7performs sub scanning, by moving the recording medium W along the Y-axis that is the transport direction. By alternately performing the main scanning and the sub scanning, a desired image based on the recording data is recorded on the recording medium W.

Next, a method for determining a working gap WG that is a distance between the second recording medium W2, which is the recording medium W for which the thickness of the medium is unknown, and the recording head15will be described with reference toFIG. 3toFIG. 10.FIG. 3is a flowchart illustrating the method for determining the working gap.FIG. 4,FIG. 6, andFIG. 9are diagrams illustrating working gaps.FIG. 5,FIG. 7, andFIG. 10are diagrams illustrating test patterns captured by the imaging unit.FIG. 8is a diagram illustrating a relationship between the number of pixels of the captured test pattern and the working gap.

Step S101is a first recording step in which the test pattern53is recorded by ejecting the ink from the recording head onto the first recording medium W1that is the recording medium W for which the thickness of the medium is known. The control unit7controls the transport motor86and transports the first recording medium W1to a position facing the recording head15. The control unit7controls the head moving unit16and moves the carriage14from a first side to a second side along the X-axis. In this way, the recording head15and the first recording medium W1move relative to each other along the X-axis. When moving the carriage14, the control unit7controls the recording head15, and records the test pattern53on the first recording medium W1using a predetermined nozzle row. For example, the recording data that forms a frame-shaped rectangle can be employed as the test pattern53.

Step S102is a first imaging step in which the test pattern53recorded on the first recording medium W1is captured. As illustrated inFIG. 4, the control unit7raises and lowers the gap adjustment unit220, and sets the working gap WG, which is the distance between the recording head15and the first recording medium W1, to a first distance WG1. Using the gap adjustment unit20, the recording head15is set to a specified height with respect to the transporting belt64. Since the thickness of the medium is known for the first recording medium W1, the first distance WG1can be determined. The first distance WG1is preferably a lower limit at which the working gap WG can be set. The control unit7controls the driving of the transport motor86and the head moving unit16, and causes the test pattern53recorded on the first recording medium W1and the imaging unit50to face each other. Using the imaging unit50, the control unit7captures the test pattern53at the first distance WG1. For example, the imaging unit50captures the test pattern53inside the imaging range52, at 1920×1080 pixels.FIG. 5illustrates the test pattern53captured at the first distance WG1.

At the first distance WG1, the test pattern53is enlarged or reduced to a predetermined size using the zoom lens51of the imaging unit50. As the predetermined size, for example, a size along the X-axis of the test pattern53is set to 80% or more of the imaging range52. In this way, any recording data other than the test pattern53can be handled as a test pattern. In addition, when any recording data that is smaller than the predetermined size is used as the test pattern, the accuracy of a function WN to be described below can be improved by enlarging the test pattern. A user may manually manipulate the image of the imaging unit50displayed on the input device10while viewing the image, or the control unit7may calculate the number of pixels of the test pattern53and may perform control using a control signal based on a result of the calculation.

As illustrated inFIG. 6, the control unit7raises and lowers the gap adjustment unit220, and sets the working gap WG to a second distance WG2. The second distance WG2is preferably an upper limit at which the working gap WG can be set. Using the imaging unit50, the control unit7captures the test pattern53at the second distance WG2.FIG. 7illustrates the test pattern53captured at the second distance WG2.

Step S103is a function calculating step in which the function WN is calculated that is used to determine the working gap WG from the number of pixels NP of the captured test pattern53, based on the number of pixels NP1of the test pattern53captured at the first distance WG1and the number of pixels NP2of the test pattern53captured at the second distance WG2. The CPU73of the control unit7calculates the number of pixels NP1of a length along the X-axis of the test pattern53captured at the first distance WG1, and the number of pixels NP2of a length along the X-axis of the test pattern53captured at the second distance WG2. As illustrated inFIG. 8, the CPU73calculates the function WN that is used to determine the working gap WG from the number of pixels NP, based on the number of pixels NP1of the test pattern53with respect to the first distance WG1and the number of pixels NP2of the test pattern53with respect to the second distance WG2, and stores the calculated function WN in the storage unit75. The vertical axis inFIG. 8indicates inverse numbers of the number of pixels NP of the test pattern53, and the horizontal axis indicates the working gap WG. The function WN is a straight line on which the inverse number of the number of pixels NP and the working gap WG are proportional to each other. By setting the first distance WG1as the lower limit of the working gap WG and the second distance WG2as the upper limit of the working gap WG, that is, by increasing the difference between the first distance WG1and the second distance WG2, accuracy when calculating the function WN can be improved.

Step S104is a second recording step in which the test pattern53is recorded on the second recording medium W2, which is the recording medium W for which the thickness of the medium is unknown. The control unit7controls the transport motor86and transports the second recording medium W2to the position facing the recording head15. As illustrated inFIG. 9, the control unit7raises and lowers the gap adjustment unit220, and sets the distance between the recording head15and the second recording medium W2to a third distance WG3, which is the desired working gap WG. Using the gap adjustment unit220, the recording head15is set to a specified height with respect to the transporting belt64. Since the thickness of the medium of the second recording medium W2is unknown, the third distance WG3at the time of recording the test pattern53on the second recording medium W2is also unknown. The control unit7controls the head moving unit16and moves the carriage14from the first side to the second side along the X-axis. As a result, the recording head15and the second recording medium W2move relative to each other along the X-axis. When moving the carriage14, the control unit7controls the recording head15, and records the test pattern53on the second recording medium W2using a predetermined nozzle row.

Step S105is a second imaging step in which the test pattern53recorded on the second recording medium W2is captured. The control unit7controls the driving of the transport motor86and the head moving unit16, and causes the test pattern53recorded on the second recording medium W2to face the imaging unit50. The control unit7captures the test pattern53using the imaging unit50, at the third distance WG3.FIG. 10illustrates the test pattern53captured at the third distance WG3.

Step S106is a working gap determining step in which the third distance WG3, which is the unknown working gap WG, is determined. The CPU73of the control unit7calculates the number of pixels NP3of the length along the X-axis of the test pattern53captured in the second imaging step. Then, the CPU73refers to the function WN stored in the storage unit75, and, based on the number of pixels NP3and the function WN, determines the third distance WG3, which is the working gap WG at the time of recording the test pattern53on the second recording medium W2in the second recording step. In this way, the working gap WG can be determined when using the second recording medium W2for which the thickness of the medium is unknown. Further, the CPU73calculates the thickness of the second recording medium W2based on the height of the recording head15with respect to the transporting belt64and on the third distance WG3.

Note that, in this embodiment, the description is given in which the function WN and the unknown working gap WG are determined based on the number of pixels NP of the length along the X-axis of the captured test pattern53, but the function WN and the unknown working gap WG may be determined based on the number of pixels of a length along the Y-axis of the test pattern53.

According to the above-described method for determining the working gap and recording device1of this embodiment, the following effects can be achieved.

The method for determining the working gap captures, at the first distance WG1and at the second distance WG2, the test pattern53recorded on the first recording medium W1, for which the thickness of the medium is known, and, using the number of pixels NP1and NP2of each of the captured test patterns53and the first distance WG1and the second distance WG2, calculates the function WN that determines the working gap WG based on the number of pixels NP. In this way, even when the thickness of the second recording medium W2is unknown, the third distance WG3, which is the working gap WG at the time of recording the test pattern53on the second recording medium W2, can be determined based on the number of pixels NP3of the test pattern53that is recorded on the second recording medium W2and captured, and the function WN. Thus, the method for determining the working gap can be provided for determining the working gap WG of the recording medium W for which the thickness of the medium is unknown.

The first distance WG1is preferably the lower limit of the working gap WG and the second distance WG2is preferably the upper limit of the working gap WG. In this way, by increasing the difference between the first distance WG1and the second distance WG2, the accuracy when determining the function WN can be improved.

The imaging unit50is provided with the zoom lens51. Because the test pattern53is enlarged or reduced to the predetermined size by the zoom lens51, any recording data other than the test pattern53can be handled as the test pattern. Further, when any recording data smaller than a predetermined size is used as the test pattern, the accuracy when determining the function WN can be improved by expanding the test pattern.

The control unit7of the recording device1captures, at the first distance WG1and the second distance WG2, the test pattern53recorded on the first recording medium W1for which the thickness of the medium is known, and, using the number of pixels NP1and NP2of each of the captured test patterns53and the first distance WG1and the second distance WG2, calculates the function WN that determines the working gap WG based on the number of pixels NP. In this way, even when the thickness of the second recording medium W2is unknown, the third distance WG3, which is the working gap WG at the time of recording the test pattern53on the second recording medium W2, can be determined based on the number of pixels NP3of the test pattern53that is recorded on the second recording medium W2and captured, and the function WN. Thus, the recording device1can be provided for determining the working gap WG of the recording medium W for which the thickness of the medium is unknown.

Note that, the present disclosure is not limited to the embodiment described above, and various modifications and improvements can be added to the above-described embodiment. Modified examples are described below.

FIG. 11is a diagram illustrating a test pattern captured by the imaging unit according to Modified Example 1. A test pattern55described in Modified Example 1 differs in shape from the test pattern53described in the embodiment.

The test pattern55is a pattern used to adjust a recording position along the X-axis. As illustrated inFIG. 11, the test pattern55is configured by a first region Fd and a second region Sd. The first region Fd is recorded by a forward movement in which the carriage14moves from the first side to the second side along the X-axis. The second region Sd is recorded by a return movement in which the carriage14moves from the second side to the first side along the X-axis. A plurality of rectangular patterns that are long along the Y-axis are arranged at equal intervals along the X-axis in the first region Fd and the second region Sd. The interval between the rectangular patterns disposed in the first region Fd and the interval between the rectangular patterns disposed in the second region Sd are different, and one end of each of the rectangular patterns disposed in the first region Fd overlaps with one end of each of the rectangular patterns disposed in the second regions Sd.

The positions of the rectangular pattern of the first region Fd and the rectangular pattern of the second region Sd disposed in the center of the X-axis are aligned with each other on the X-axis. A degree of displacement in arrangement positions, on the X-axis, between the rectangular patterns of the first region Fd and the rectangular patterns of the second region Sd increases toward both ends of the X-axis. The test pattern55is recorded on the recording medium W, and the recording positions recorded along the X-axis at the forward movement and the return movement can be adjusted, using a correction value that accords with the position at which the rectangular pattern of the first region Fd and the rectangular pattern of the second region Sd are aligned on the X-axis.

In the flow of determining the working gap WG described in the embodiment, the test pattern55may be used instead of the test pattern53. As illustrated inFIG. 11, the imaging unit50is provided with the zoom lens51, and therefore, the test pattern55can be captured at a predetermined size, and the number of pixels NP of a length along the X-axis of the captured test pattern55can be determined. In the flow of determining the working gap WG, by using the test pattern55, the working gap can be determined and the recording position along the X-axis can be adjusted simultaneously.

FIG. 12is a diagram illustrating the recording head15according to Modified Example 2. The recording head15of Modified Example 2 is configured by a plurality of recording heads.

As illustrated inFIG. 12, the recording head15includes a first recording head15aand a second recording head15b, and is mounted on the carriage14. The second recording head15bis positioned on the positive side along the X-axis and on the negative side along the Y-axis with respect to the first recording head15a, and part of the second recording head15boverlaps with the first recording head15ain a side view from the X-axis direction.

When the recording head15has the plurality of recording heads, the working gap WG may be determined using the following steps. At S101to S103, processing similar to the above-described example is performed for each of the first and second recording heads15aand15b, and a function for the first recording head15aand a function for the second recording head15bare obtained. At S104, the one first recording head15a, of the plurality of recording heads, performs the recording on the second recording medium W2. At S105and S106, processing similar to the above-described embodiment is performed for the first recording head15aand the working gap WG3of the first recording head15ais determined. Then, as a new step S107, the working gap WG3of the second recording head15bis determined based on the working gap WG3of the first recording head15aand the function for the second recording head15b.

In this way, a measurement time can be shortened by determining the working gap WG of the other recording head from the result for the first recording head. Note that the recording head15can achieve the same effect even in a configuration in which three or more of the recording heads are arranged along the X-axis and the Y-axis.

Contents derived from the embodiment will be described below.

A method for determining a working gap of the present application includes a first recording step for ejecting ink from a recording head onto a first recording medium having a known medium thickness to record a test pattern, a first imaging step for capturing the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, a function calculating step for calculating, based on the number of pixels of the test pattern captured at the first distance and the number of pixels of the test pattern captured at the second distance, a function to determine the distance based on the number of pixels of the captured test pattern, a second recording step for recording the test pattern on a second recording medium, a second imaging step for capturing the test pattern recorded on the second recording medium, and a working gap determining step for determining, based on the number of pixels of the captured test pattern and the function, a distance between the recording head and the second recording medium.

According to this method, the method for determining the working gap captures, at the first distance and at the second distance, the test pattern recorded on the first recording medium for which the thickness of the medium is known, and, based on the number of pixels of the test pattern captured at the first distance and at the second distance, calculates the function used to determine the working gap based on the number of pixels of the captured test pattern. In this way, even when the thickness of the second recording medium is unknown, it is possible to determine the distance between the recording head and the second recording medium, that is, the so-called working gap, based on the number of pixels of the test pattern recorded on the second recording medium and captured, and on the function. Thus, the method for determining the working gap can be provided for determining the working gap for the recording medium for which the thickness of the medium is unknown.

In the above-described method for determining the working gap, preferably, the test pattern is a pattern that is recorded by relative movement, along a first axis, of the recording head and one of the first recording medium and the second recording medium, and is used for adjusting a recording position along the first axis.

According to this method, the working gap can be determined and the recording position along the first axis can be adjusted simultaneously.

In the above-described method for determining the working gap, preferably, the first distance is a lower limit of the distance between the recording head and the first recording medium, and the second distance is an upper limit of the distance between the recording head and the first recording medium.

According to this method, by increasing the difference between the first distance and the second distance, accuracy when determining the function can be improved.

In the above-described method for determining the working gap, preferably, at the first distance of the first imaging step, the test pattern is enlarged or reduced to a predetermined size.

According to this method, any image can be treated as the test pattern for determining the working gap. Further, when any recording data that is smaller than a predetermined size is used as the test pattern, the accuracy when determining the function can be improved by enlarging the test pattern.

In the above-described method for determining the working gap, preferably the recording head includes a first recording head and a second recording head, in the second recording step, the test pattern is recorded, by the first recording head, onto the second recording medium, in the second imaging step, the test pattern recorded on the second recording medium is captured, and in the working gap determining step, a distance between the first recording head and the second recording medium is determined based on the number of pixels of the captured test pattern and the function, and a distance between the second recording head and the second recording medium is determined based on the distance between the first recording head and the second recording medium and the function for the second recording head.

According to this method, when the recording head is configured by the plurality of recording heads, such as the first recording head and the second recording head, the distance between the second recording head and the second recording medium is determined based on a result for the first recording head. In this way, a measurement time for determining the distance between each of the plurality of recording heads and the second recording medium can be shortened.

A recording device of the present application includes a recording head configured to record a test pattern, a gap adjustment unit configured to adjust a height of the recording head, an imaging unit configured to capture the test pattern, and a control unit. The control unit records the test pattern on a first recording medium having a known medium thickness, captures the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, calculates, based on the number of pixels of the test pattern captured at the first distance and the number of pixels of the test pattern captured at the second distance, a function to determine the distance based on the number of pixels of the captured test pattern, records the test pattern on a second recording medium, captures the test pattern recorded on the second recording medium, and determines, based on the number of pixels of the captured test pattern and the function, a working gap that is a distance between the recording head and the second recording medium.

According to this configuration, the control unit captures, at the first distance and the second distance, the test pattern recorded on the first recording medium for which the thickness of the medium is known, and, based on the number of pixels of the test pattern captured at the first distance and the second distance, calculates the function used to determine the working gap based on the number of pixels of the captured test pattern. In this way, even when the thickness of the second recording medium is unknown, it is possible to determine the distance between the recording head and the second recording medium, that is, the so-called working gap, based on the number of pixels when the test pattern recorded on the second recording medium is captured, and on the function. Thus, the recording device can be provided for determining the working gap for the recording medium for which the thickness of the medium is unknown.