Patent Description:
The present disclosure relates to a recording device and a recording method.

A recording device is known to record onto a medium by alternately repeating scanning the medium with a recording head having a nozzle array with nozzles that eject ink and transporting the medium in a transport direction that intersects the scanning direction of the recording head. Examples of recording devices are described in <CIT>; <CIT>; and <CIT>. In such a recording device, there is an error from the design value with respect to transport accuracy, and there are individual differences in such transport errors. Due to the transport errors, streaky density unevenness with relatively high or low density may occur at a boundary area between a band that is an image to be recorded in one scan and a band that is to be recorded in the next scan. To suppress the occurrence of such uneven density, a test pattern is recorded on the medium by two times of scans, and the transport amount of one time between scans is adjusted by evaluating the density of the aforementioned boundary area in the test pattern.

<CIT> discloses, as a related technology, recording an adjustment pattern including multiple patches arranged in the scanning direction of the recording head. According to <CIT>, each patch includes a reference pattern recorded by a first recording scan and, after an intervening transport, a displacement pattern recorded by the second recording scan, where the displacement differs from the reference pattern for each patch.

When adjusting the transport amount as described above, the medium is transported a predetermined distance, corresponding to the length of the nozzle array in the transport direction, between the two scans for recording the test pattern. Here, a transport roller that rotates to transport the medium may not be a perfect circle or may be eccentric in its cross-sectional shape. If there is a "transport roller error", which is an error of the transport roller itself, such as a non-perfect circle or eccentricity, the transport amount relative to the rotation amount fluctuates during a single transport roller revolution. Therefore, when the length of the nozzle array differs from the circumference length of the transport roller, test pattern recording results are affected by transport roller error, and it is difficult to obtain a correct adjustment value for the transport amount from the test pattern recording results.

In view of such circumstances, there is a demand for a test pattern that helps to eliminate as much as possible the influence of transport roller error and to obtain a correct adjustment value to suppress uneven density.

The recording device includes a recording head that has a nozzle array with a plurality of nozzles for ejecting liquid onto a medium, the nozzles being arranged in a predetermined nozzle alignment direction, and that ejects liquid while moving in a first direction that intersects the nozzle alignment direction to perform recording; a transport section that has a transport roller configured to rotate to transport the medium and that transports the medium in a second direction that intersects the first direction; and a control section that controls recording by the recording head and transport by the transport section, wherein: a circumference length of the transport roller is different from a nozzle array length, which is a length of the nozzle array in the second direction and the control section performs TP recording control to record, on the medium, a group of test patterns, in which a plurality of test patterns including a first patch and a second patch with different positions in the second direction are arranged in the first direction and an amount of liquid ejected for a boundary area between the first patch and the second patch is different in the first direction for each test pattern and, in the TP recording control, records a first test pattern group and a second test pattern group, which are the test pattern groups, at different positions in the second direction on the medium, transports the medium by a first distance based on the nozzle array length as a transport between the recording of the first patch and the second patch of the test pattern, and transports the medium by a second distance, which is a difference between an integer multiple of the circumference length and two times the first distance, as a transport between the recording of the second patch of the first test pattern group and the recording of the first patch of the second test pattern group.

A recording method of a recording device, the recording device including a recording head that has a nozzle array with a plurality of nozzles for ejecting liquid onto a medium, the nozzles being arranged in a predetermined nozzle alignment direction, and that ejects liquid while moving in a first direction that intersects the nozzle alignment direction to perform recording; and a transport section that has a transport roller configured to rotate to transport the medium and that transports the medium in a second direction that intersects the first direction, wherein a circumference length of the transport roller is different from a nozzle array length, which is a length of the nozzle array in the second direction, the method comprising: a TP recording step for recording, on the medium, a group of test patterns, in which a plurality of test patterns including a first patch and a second patch with different positions in the second direction are arranged in the first direction, and in which an amount of liquid ejected for a boundary area between the first patch and the second patch is different for each test pattern in the first direction, wherein the TP recording step records a first test pattern group and a second test pattern group, which are the test pattern groups, at different positions in the second direction on the medium, transports the medium by a first distance based on the nozzle array length as a transport between the recording of the first patch and the second patch of the test pattern, and transports the medium by a second distance, which is a difference between an integer multiple of the circumference length and two times the first distance, as a transport between the recording of the second patch of the first test pattern group and the recording of the first patch of the second test pattern group.

The following is a description of embodiments of this disclosure with reference to each figure. Each figure is merely an example to explain this embodiment. Since each figure is an example, proportions, shapes, and the shades may not be exact or consistent with each other, and some may be omitted.

<FIG> shows a simplified configuration of a recording device <NUM> in this embodiment. A recording method is executed by the recording device <NUM>. The recording device <NUM> is equipped with a control section <NUM>, a display section <NUM>, an operation section <NUM>, a storage section <NUM>, a communication IF <NUM>, a transport section <NUM>, a carriage <NUM>, a recording head <NUM>, and the like. IF is an abbreviation for interface. The control section <NUM> is composed of one or more ICs having a CPU 11a as a processor, a ROM 11b, a RAM 11c, and the like, and other nonvolatile memory, and the like.

In the control section <NUM>, the processor, that is, the CPU 11a executes calculation processing according to a program <NUM> stored in the ROM 11b or other memory, by using the RAM 11c or the like as a work area, to realize various functions such as a TP recording control section 12a and an adjustment value calculation section 12b. TP is an abbreviation for test pattern. The program <NUM> corresponds to a recording control program. The TP recording control section 12a and the adjustment value calculation section 12b are just some of the functions that the recording device <NUM> realize according to the program <NUM>. The processor is not limited to a single CPU, but may be configured to perform processing using multiple CPUs or hardware circuits such as an ASICs, or CPUs and hardware circuits may work together to perform processing.

The display section <NUM> is a unit for displaying visual information and is composed of, for example, a liquid crystal display, an organic EL display, or the like. The display section <NUM> may include a display and a drive circuit for driving the display. The operation section <NUM> is a unit for accepting operations or input by a user, and is realized, for example, by physical buttons, a touch panel, a mouse, a keyboard, or the like. The display section <NUM> and the operation section <NUM> may be collectively referred to as an operation panel of the recording device <NUM>. The operation section <NUM> as a touch panel is realized as a function of the display section <NUM>. Therefore, the display section <NUM> may be interpreted as including the operation section <NUM>.

The storage section <NUM> is, for example, a hard disk drive, a solid state drive, or other memory storage unit. A portion of the memory that the control section <NUM> has may be considered as the storage section <NUM>. The storage section <NUM> may be considered as a part of the control section <NUM>.

The communication IF <NUM> is a general term for one or more IFs that enable the recording device <NUM> to perform wired or wireless communication with external devices in accordance with predetermined communication protocols, including known communication standards. The communication IF <NUM> corresponds to a communication section. The external devices are, for example, personal computers (PCs), servers, smartphones, or tablet terminals, and other communication devices. In the example in <FIG>, the recording device <NUM> is connected to the reading device <NUM> via a communication IF <NUM>. The number of external devices to which the recording device <NUM> is communicatively connected is not limited to one. The reading device <NUM> is a unit that can read the medium <NUM> after recording by the recording device <NUM>, and may be a scanner or a colorimeter. The reading device <NUM> may be a part of the recording device <NUM>.

The transport section <NUM> is a unit for transporting the medium <NUM> along a predetermined transport path under control of the control section <NUM>. The transport section <NUM> is equipped with a transport roller that rotates to transport the medium <NUM>, a motor as a power source for rotation, and the like. The medium <NUM> is, for example, paper, but it can be any medium that can be subject to recording with liquid, and it can be a material other than paper, such as a film or a fabric.

The carriage <NUM> is a movement unit that reciprocates along a predetermined main scanning direction under the control of the control section <NUM> and is powered by a carriage motor (not shown). The carriage <NUM> has mounted thereon the recording head <NUM>. The main scanning direction corresponds to a "first direction". The recording head <NUM> is a unit that ejects liquid onto the medium <NUM> using an inkjet method under the control of the control section <NUM>. Droplets ejected by the recording head <NUM> are called dots. The liquid is mainly ink.

The recording head <NUM> is capable of ejecting inks of each color, for example, cyan (C), magenta (M), yellow (Y), and black (K). Of course, the recording head <NUM> may be capable of ejecting inks of colors other than CMYK or liquid other than ink. Movement of the carriage <NUM> and movement of the recording head <NUM> mean the same thing. The carriage <NUM> and the recording head <NUM> may be considered collectively as the recording head, or they may be referred to as a recording section.

The recording device <NUM> is a single printer whose components are integrated into a single unit. Alternatively, the recording device <NUM> may be a recording system realized by multiple devices or equipment communicatively connected to each other. The recording system includes, for example, an information processing device, which primarily serves as the control section <NUM>, and a printer, which includes the transport section <NUM>, the carriage <NUM>, and the recording head <NUM> to perform recording under the control of the information process device. In this case, the information process device can be considered a recording control device, an image processing device, or the like. The display section <NUM>, the operation section <NUM>, and the storage section <NUM> may be a part of the information processing device or the printer, or they may be peripheral devices connected to the information processing device or the printer.

<FIG> shows a simplified view of the relationship between the recording head <NUM> and the medium <NUM> as viewed from above. The recording head <NUM> has a plurality of nozzles <NUM> capable of ejecting liquid. Each of white circles shown in <FIG> is an individual nozzle <NUM>. The direction D2 that intersects the main scanning direction D1 is referred to as a sub-scanning direction D2 or a transport direction D2. The main scanning direction D1 and the transport direction D2 is orthogonal or substantially orthogonal. The transport direction D2 corresponds to a "second direction. " The transport section <NUM> transports the medium <NUM> from upstream to downstream in the transport direction D2, as indicated by the arrow of the transport direction D2. Upstream and downstream in the transport direction D2 are simply referred to as upstream and downstream.

The recording head <NUM> has a nozzle array for each liquid type. In <FIG>, the nozzle arrays 21C, <NUM>, 21Y, and <NUM> are shown very simply as the nozzle arrays. Each of the nozzle arrays 21C, <NUM>, 21Y, and <NUM> is composed of a plurality of nozzles <NUM> aligned in a predetermined nozzle alignment direction D3. In the example of <FIG>, the nozzle alignment direction D3 is parallel to the transport direction D2. However, as a structure of the recording head <NUM>, the nozzle alignment direction D3 may be inclined at an angle to the transport direction D2. In any case, the nozzle alignment direction D3 intersects the main scanning direction D1. A nozzle array includes a plurality of nozzles <NUM> that are arranged in a row with a constant or nearly constant nozzle pitch, which is the distance between nozzles <NUM> in the transport direction D2.

The nozzle array 21C is a nozzle array with a plurality of nozzles <NUM> that eject C ink are arranged. Similarly, the nozzle array <NUM> is a nozzle array with a plurality of nozzles <NUM> that eject M ink, the nozzle array 21Y is a nozzle array with a plurality of nozzles <NUM> that eject Y ink, and the nozzle array <NUM> is a nozzle array with a plurality of nozzles <NUM> that eject K ink. The plurality of nozzle arrays 21C, <NUM>, 21Y, and <NUM> are arranged along the main scanning direction D1, and are at identical positions with respect to the transport direction D2.

The length of the nozzle array in the transport direction D2 is called as a "nozzle array length". The nozzle array length can be interpreted as a distance in the transport direction D2 between the most downstream nozzle <NUM> and the most upstream nozzle <NUM>. However, if some of nozzles <NUM> at the downstream end or the upstream end of the nozzle array are not used to eject liquid as a specification, the nozzle array length can be understood as the length of the nozzle array excluding such nozzles <NUM> at the downstream end or the upstream end that are not used.

The control section <NUM> causes the recording head <NUM> to eject ink based on recording data representing an image to be recorded. As is known, the recording head <NUM> has drive elements for each of the nozzles <NUM>, and by controlling the application of drive signals to the drive elements of each of the nozzles <NUM> according to the recording data, each of the nozzles <NUM> ejects or does not eject a dot of the corresponding ink, and an image represented by the recording data is recorded on the medium <NUM>. The recording data is data that specifies whether or not dots are to be ejected for each pixel and each ink color, such as CMYK. Ejection of dots is also referred to as dot-on, and the non-ejection of dots is also referred to as dot-off.

Ejecting liquid from the recording head <NUM> while the carriage <NUM> moves the recording head <NUM> in the main scanning direction D1 is called "scanning" or "pass". The transport of the medium <NUM> downstream by the transport section <NUM> between passes is called "paper feed". The control section <NUM> records a two-dimensional image on the medium <NUM> by alternately repeating the pass and the paper feed. Movement from one side to the other side along the main scanning direction D1 is called outward path movement, and the movement from the other side to the one side is called return path movement. In addition, a pass by an outward path movement is called an outward pass, and a pass by a return path movement is called a return pass. Recording by using the outward path and the return path is bidirectional recording, and recording by using only one of the outward path and the return path is unidirectional recording. In this embodiment, either bidirectional recording or unidirectional recording may be used.

<FIG> shows a simplified view of a configuration, including the recording head <NUM> and the transport roller, from the viewpoint in the direction parallel to the main scanning direction D1. The recording head <NUM> is located above the medium <NUM>. In <FIG>, the recording head <NUM> and the carriage <NUM> mounted with the recording head <NUM> are shown as a single unit. The lower surface of the recording head <NUM> is a nozzle surface 19a. At the nozzle surface 19a, each of the nozzles <NUM> are opened, and dots are ejected from the nozzle surface 19a onto the medium <NUM>.

The transport section <NUM> has a transport roller 17a and a transport motor 17b that powers the transport roller 17a in rotation. From the transport motor 17b to the transport roller 17a is connected via a gear wheel train, a belt, or the like (not shown), to transmit the power. The transport roller 17a is located upstream from the recording head <NUM> and transports the medium <NUM> by rotating while in contact with the medium <NUM>. The cross-sectional shape of the transport roller 17a is a circle and, as shown in the figure, the circumference of this circle is the circumference length of the transport roller 17a. Although omitted in <FIG>, the transport section <NUM> may have a roller that contacts in the medium <NUM> and rotates in a driven manner or a platen that supports medium <NUM>.

<FIG> shows a different example from <FIG>, from the same viewpoint as <FIG>. With respect to <FIG>, the explanation common to <FIG> will be omitted. Multiple transport rollers may be located along the transport direction D2. The transport rollers that have the same position with respect to the transport direction D2 are not referred to as multiple transport rollers in this embodiment. For example, the transport roller 17a may be divided in the main scanning direction D1. In the example of <FIG>, the transport section <NUM> has the transport roller 17a and a transport roller 17c as transport rollers rotated by the transport motor 17b. Between the transport motor 17b and the transport roller 17c are connected by a gear wheel train, a belt, or the like (not shown), to transmit the power. The transport roller 17c is located downstream from the recording head <NUM>, and transport the medium <NUM> by rotating while in contact with the medium <NUM>. The cross-sectional shape of the transport roller 17c is a circle as shown in the figure, and the circumference of this circle is the circumference length of the transport roller 17c. In the example of <FIG>, the transport amount per unit time is designed to be balanced between the transport roller 17a and the transport roller 17c.

In the following, the number of transport rollers may be one, as shown in <FIG>, or multiple, as shown in <FIG>. However, when there are multiple transport rollers, the multiple transport rollers are considered to be one virtual transport roller, and "circumference length of the transport roller" is the common multiple of the circumference lengths of the multiple transport rollers. The common multiple here can be basically interpreted as the least common multiple, but it does not necessarily have to be the least common multiple. When the example of <FIG> is used, "circumference length of the transport roller" is the least common multiple of the circumference length of the transport roller 17a and the circumference length of the transport roller 17c. In this embodiment, the explanation will be continued assuming that the nozzle array length and the circumference length of the transport roller are different from each other. The nozzle array length and the circumference length of the transport roller are known values in each product.

<FIG> shows a flowchart of the process from recording a TP group to obtaining an adjustment value, which is executed by the control section <NUM> according to the program <NUM>. Steps S100 to S160 in this flowchart correspond to a "TP recording control" or a "TP recording step" in this embodiment. <FIG> shows a plurality of "TP groups" recorded onto the medium <NUM> by the recording head <NUM> in the TP recording control, from the same viewpoint as <FIG>. In <FIG>, the recording head <NUM> is shown as a mere rectangle box, and the carriage <NUM> is omitted.

In step S100, the TP recording control section 12a of the control section <NUM> controls the carriage <NUM> and the recording head <NUM>, and causes the recording head <NUM> to eject ink based on the TP group recording data, which is the recording data representing the TP group, and to record a plurality of first patches <NUM> of the first TP group <NUM> on the media <NUM> in one pass. The TP group recording data is stored in advance, for example, in the storage section <NUM>.

In this embodiment, one TP group is formed by a plurality of TPs aligned in, and separated by spaces in, the main scanning direction D1. In the following, right and left which is viewed from the upstream toward the downstream are simply referred to right and left. In the example of <FIG>, the first TP group <NUM> is formed by five TPs 40a, 40b, 40c, 40d, and 40e, which are equally spaced from left to right. Similarly, the second TP group <NUM> is formed by five TPs 40a, 40b, 40c, 40d, and 40e, which are equally spaced from left to right. Of course, the number of TPs forming one TP group is not limited to five. One TP is formed by the first patch <NUM> and the second patch <NUM> at positions that differ in the transport direction D2. In one TP, the patch on the downstream side is the first patch <NUM>, and the patch on the upstream side is the second patch <NUM>. In <FIG>, the symbols <NUM> and <NUM>, and a symbol <NUM> indicating a "boundary area" are omitted from the TPs 40a, 40b, 40d, and 40e except for the TP40c.

The first patch <NUM> and the second patch <NUM> are plain images, each recorded with one color of ink. The color of the first patch <NUM> and the color of the second patch <NUM> may be the same or different. For simplicity, it is assumed that the first patch <NUM> and the second patch <NUM> are recorded with the same color, for example, C ink. Therefore, in <FIG>, the recording head <NUM> may be considered as single nozzle array, for example, the nozzle array 21C, which ejects ink of one color.

In the transport direction D2, each of the first patches <NUM> and the second patches <NUM> may be band size images, which are recorded using all or substantially all of the nozzles <NUM> over the nozzle array length. However, the TP should be an image that enables evaluation of the density of the boundary area <NUM>, as will be described later, so each of the first patches <NUM> and the second patches <NUM> may be an image of smaller size than the band size in the transport direction D2. In the example in <FIG>, the first patch <NUM> is an image recorded by using some of the consecutive nozzles <NUM> on the upstream side of the nozzle array, and the second patch <NUM> is an image recorded by using some of the consecutive nozzles <NUM> on the downstream side of the nozzle array. Thereby, ink consumption amount can be suppressed when recording the TP.

The four recording heads <NUM> shown in <FIG> with their positions shifted along the transport direction D2 are all the same recording head <NUM>. The symbols P1, P2,. shown next to the symbol <NUM> mean which number pass each is. In other words, <FIG> shows that the recording head <NUM> has performed the first to fourth passes P1, P2, P3, and P4, and that the positional relationship between the recording head <NUM> and the medium <NUM> in the transport direction D2 is different for each pass P1, P2, P3, and P4 due to the transport of the medium <NUM>. As can be seen from <FIG>, the plurality of first patches <NUM> of the first TP group <NUM> are recorded by the pass P1.

In step S110, the TP recording control section 12a controls the transport section <NUM> to perform a "first paper feed". The first paper feed in step S110 and step S150 described later is a transport between the recording of the first patch <NUM> and the recording of the second patch <NUM> in the TP. The TP recording control section 12a performs the first paper feed by instructing the transport section <NUM> to transport a "first distance" based on the nozzle array length. The symbol L1 indicates the first distance L1. The first distance L1 based on the nozzle array length is a predetermined one-time paper feed amount. The first distance L1 may be, for example, the nozzle array length itself. However, to avoid gaps in the transport direction D2 between images recorded in each successive pass, and in consideration of an adjustment value using an adjustment value for each TP 40a, 40b, 40c, 40d, and 40e, which will be described later, the first distance L1 is assumed to be shorter than the nozzle array length by a predetermined number of nozzle pitches.

By setting the first distance L1 to a distance that is shorter than the nozzle array length by a predetermined number of nozzle pitches, an upstream end of the first patch <NUM> and a downstream end of the second patch <NUM> can easily overlap. If an error in transport accuracy by the transport section <NUM> when compared to the design ideal, that is, "transport error," is zero, then when the transport section <NUM> is instructed to transport a certain distance, the transport of the instructed distance will be performed accurately. However, because of possible transport errors, the distance instructed to the transport section <NUM> may not always be actually achieved. Thus, even when described in this embodiment that to transport by the first distance, or that the transport section <NUM> is instructed to transport the first distance and perform the first paper feed, and the like, these do not mean that the transport of the first distance is realized exactly. Such an interpretation is applied to a second distance transport and a second paper feed, which will be described later.

In step S120, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM>, and causes the recording head <NUM> to eject ink based on the TP group recording data to record a plurality of the second patches <NUM> of the first TP group <NUM> onto the media <NUM> in a single pass. In other words, according to <FIG>, a plurality of the second patches <NUM> of the first TP group <NUM> are recorded by the pass P2.

In this embodiment, in one TP group, the amount of liquid ejected for the boundary area <NUM> between the first patch <NUM> and the second patch <NUM> is different for each TP 40a, 40b, 40c, 40d, and 40e aligned in the main scanning direction D1. The boundary area <NUM> is the area that includes a portion where the first patch <NUM> and the second patch <NUM> are closest to each other in the TPs 40a, 40b, 40c, 40d, and 40e, which are aligned in the main scanning direction D1. Specifically, the boundary area <NUM> is, in each TP 40a to 40e, an area that is, in the transport direction D2, the larger one between an overlap region where the first patch <NUM> and the second patch <NUM> overlaps as viewed from the main scanning direction D1 and a gap region between an upstream end of the first patch <NUM> and a downstream end of the second patch <NUM>. For example, as shown in <FIG>, in the TP 40a of the first TP group <NUM>, the width in the transport direction D2 of the black streak region corresponds to the width of the boundary area <NUM>, and in the TP 40e of the second TP group <NUM>, the width in the transport direction D2 of the white streak region corresponds to the width of the boundary area <NUM>. Alternatively, the boundary area <NUM> may be an area, as viewed from the main scanning direction D1, that adds a maximum width of the overlap region where the first patch <NUM> and the second patch <NUM> overlap in each TP 40a to 40e and a maximum width of the gap between the upstream end of the first patch <NUM> and the downstream end of the second patch <NUM>. Each TP in one TP group shall be considered to have the boundary area <NUM> of the same size at the same location as viewed from the main scanning direction D1.

The <NUM>, + α, +2α, +3α, and +<NUM>α shown in <FIG> are adjustment values of liquid ejection for the boundary areas <NUM> for TP 40a, 40b, 40c, 40d, and 40e, respectively. As a specific example, α is a numerical value meaning a predetermined distance. Such adjustment values may or may not be recorded on the medium <NUM> with the TP near the corresponding TP. Among the TPs 40a, 40b, 40c, 40d, and 40e, the adjustment value for the TP 40a, which is the leftmost TP, is <NUM>. This means that the positional relationship between the first patch <NUM> and the second patch <NUM> follows the first distance L1 and is not otherwise adjusted. In other words, in the TP 40a, after the first patch <NUM> is recorded in the pass P1 and then after the first paper feed in step S110, the second patch <NUM> is recorded by the pass P2.

When the amount of the overlap portion between the first patch <NUM> and the second patch <NUM> in the boundary area <NUM> increases, the density of the boundary area <NUM> increases and is easily seen as a dark streak of unevenness. On the other hand, when the amount of the overlap portion in the boundary area <NUM> is too small, or when there is no overlap portion and a gap is created, the density of the boundary area <NUM> will decrease and will be easily seen as a bright streak of unevenness. Hereinafter, the dark streak of unevenness compared to the surrounding color will be referred to as a "black streak", and the bright streak of unevenness compared to the surrounding color will be referred to as a "white streak". The black streak does not necessarily have to be black, and similarly, the white streak does not have to be white.

In <FIG>, the adjustment value of the TP 40b recorded to the right of the TP 40a is +α. This means that after the pass P1 in which the first patch <NUM> was recorded, the second patch <NUM> was recorded in the pass P2 so that a paper feed of "first distance L1 + α" was executed. Similarly, the adjustment value of the TP 40c recorded to the right of the TP 40b is +2α. This means that after the pass P1 in which the first patch <NUM> was recorded, the second patch <NUM> was recorded in the pass P2 so that the paper feed of "first distance L1 + 2α" was executed. The adjustment value of the TP 40d recorded to the right of the TP 40c is +3α. This means that after the pass P1 in which the first patch <NUM> was recorded, the second patch <NUM> was recorded in the pass P2 so that the paper feed of "first distance L1 + 3α" was executed. The adjustment value of the TP 40e recorded to the right of the TP 40d is +4α. This means that after the pass P1 in which the first patch <NUM> was recorded, the second patch <NUM> was recorded in the pass P2 so that the paper feed of "first distance L1 + 4α" was executed.

<FIG> shows an enlarged view of a nozzle array and a part of the medium <NUM> to explain how the plurality of the second patches <NUM> are recorded in step S120. In <FIG>, the nozzle array 21C as a nozzle array is simply shown by an elongated rectangle in the transport direction D2. Due to space limitations, in <FIG>, only the TPs 40a and 40e are partially shown from among the TPs 40a, 40b, 40c, 40d, and 40e in the first TP group <NUM>. In <FIG>, the first patch <NUM> and the second patch <NUM>, which form a single TP, are shown shifted in the main scanning direction D1, in order to prioritize ease of viewing. Actually, the first patch <NUM> and the second patch <NUM> forming a single TP are recorded at the same position in the main scanning direction D1. The meanings of the symbols P1 and P2 appended to the nozzle array 21C are the same as in <FIG>.

In the pass P2, the TP recording control section 12a changes the usage range of nozzles <NUM> for each TP's second patch <NUM>, and records the second patches <NUM> of each TP 40a, 40b, 40c, 40d, and 40e. In other words, for the second patch <NUM> of TP40a with an adjustment value of <NUM>, it is sufficient that the second patch <NUM> be recorded by ink ejection using a range of nozzles including the most downstream nozzle <NUM> from amongst the plurality of nozzles <NUM> spanning the length of the nozzle array. On the other hand, in the recording of the second patch <NUM> of TPs 40b, 40c, 40d, and 40e, the range of unused nozzles is set differently for each of the TPs 40b, 40c, 40d, and 40e, to a downstream range of the nozzle array 21C including the most downstream nozzle <NUM>, in accordance with the adjustment values of +α, +2α, +3α, and +4α. Then, it is sufficient that the second patch <NUM> of each TP 40b, 40c, 40d, and 40e be recorded by ejection of ink in the same pass P2, using a range of nozzles that are not unused, that differs for each of the TPs 40b, 40c, 40d, and 40e.

For example, the second patch <NUM> of the TP 40e with the adjustment value = +4α must have its downstream edge shifted upstream by a distance equal to <NUM> × α compared to the downstream edge of the second patch <NUM> of the TP 40a with adjustment value = <NUM>. Therefore, in the course of pass P2 during the period of recording the second patch <NUM> of TP 40e, the control section <NUM> sets the unused nozzle range corresponding to <NUM> × α in the transport direction D2, to the downstream range of the nozzle array 21C that includes the most downstream nozzle <NUM>. In <FIG>, the unused nozzle range in the course of the pass <NUM> during the period of recording the second patch <NUM> of the TP 40e, is illustrated in gray. Although not shown in the figure, the TP recording control section 12a expands such unused nozzle range step by step upstream when recording the second patch <NUM> for each TP 40b, 40c, 40d, and 40e.

According to this method of recording the second patch <NUM>, second patches <NUM>, which have different positional relationships in the transport direction D2 to the corresponding first patch <NUM>, can be recorded in a single pass P2. In other words, as shown in <FIG>, it is possible to record the TP 40a, which has a relatively large amount of liquid ejection for the boundary area <NUM> between the first patch <NUM> and the second patch <NUM>, and the TP 40e, which has a relatively small amount of liquid ejection for the boundary <NUM> between the first patch <NUM> and second patch <NUM>. As can be seen from the previous explanations, TPs with an adjustment value close to <NUM> tend to generate black streaks on the boundary <NUM> because the amount of liquid ejection to the boundary area <NUM> is large and TPs with a larger adjustment value tend to generate white streaks on the boundary area <NUM> because the amount of liquid ejection to the boundary area <NUM> is smaller. As can be seen from <FIG>, the boundary area <NUM> of the TP 40a and the boundary area <NUM> of the TP 40e are common areas for the TP 40a and the TP 40e in the transport direction D2. The boundary area <NUM> shown in <FIG> is a specific example of an area, as viewed from the main scanning direction D1, that adds the maximum width of the overlap region where the first patch <NUM> and the second patch <NUM> overlap in each TP 40a to 40e and the maximum width of the gap between the upstream end of the first patch <NUM> and the downstream end of the second patch <NUM>. Furthermore, the boundary area <NUM> shown in <FIG> can be said to be an area corresponding to the difference between the range of the nozzles used when recording the second patch <NUM> in the TP 40a and the range of nozzles used when recording the second patch <NUM> in the TP 40e.

In step S130, the TP recording control section 12a controls the transport section <NUM> to perform a "second paper feed". The second paper feed is a transport between the recording of the second patch <NUM> in the first TP group <NUM> and the recording of the first patch <NUM> of a second TP group <NUM>. The TP recording control section 12a instructs the transport section <NUM> to perform the second paper feed by instructing the transport section <NUM> to transport a "second distance," which is a difference between n times the transport roller circumference length and <NUM> times the first distance L1. The symbol L2 in <FIG> indicates the second distance L2.

"n" is an integer equal to or higher than <NUM> and is the smallest integer that satisfies the following relationship: <MAT>.

In step S140, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM> to cause the recording head <NUM> to eject ink based on the TP group recording data to record a plurality of first patches <NUM> of the second TP group <NUM> onto the media <NUM> in a single pass. According to <FIG>, the plurality of first patches <NUM> of the second TP group <NUM> are recorded by the path P3.

In step S150, the TP recording control section 12a controls the transport section <NUM> to perform the first paper feed. In step S160, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM> to cause the recording head <NUM> to eject ink based on the TP group recording data to record a plurality of second patches <NUM> of the second TP group <NUM> onto the media <NUM> in a single pass. According to <FIG>, the plurality of second patches <NUM> of the second TP group <NUM> are recorded by the pass <NUM>.

The explanation of steps S140 to S160 applies similarly to steps S100 to S120. In this way, the process of recording the second TP group <NUM> by the pass P3, one first paper feed, and the pass P4, in steps S140-S160, is not different from the process of recording the first TP group <NUM> by the pass P1, one first paper feed, and pass P2, in steps S100-S120, except for the recording position of the TP group on the media <NUM> in the transport direction D2. According to steps S100 to S160, the first TP group <NUM> and the second TP group <NUM> are recorded on the medium <NUM> at different positions in the transport direction D2. The total distance of the first paper feed, the second paper feed, and the first paper feed in steps S110, S130, and S150 is n times the circumference length of the transport roller.

If there is no transport error, there will be no or little difference between the recording results of the first TP group <NUM> and the second TP group <NUM> on the medium <NUM>. In reality, however, there is a difference between the recording result of the first TP group <NUM> and the result of the second TP group <NUM> due to the transport errors. In the example in <FIG>, in the first TP group <NUM>, a black streak occurs in the boundary areas <NUM> of the TPs 40a, 40b, and 40c, a white streak occurs in the boundary area <NUM> of the TP 40e, and almost no black streak or white streak occurs in the boundary area <NUM> of the TP 40d. On the other hand, in the second TP group <NUM>, a black streak occurs in the boundary area <NUM> of the TP 40a, a white streak occurs in the boundary areas <NUM> of the TPs 40c, 40d, and 40e, and almost no black streak or white streak occurs in the boundary <NUM> of the TP 40b.

In the example shown in <FIG>, the second TP group <NUM> has a stronger tendency to generate the white streaks as a whole than the first TP group <NUM>. From this, it can be inferred that the actual paper transport amount by the first paper feed in step S150 was greater than the actual paper transport amount by the first paper feed in step S110. As described above, the transport roller may not be perfectly circular or may be eccentric in its cross-sectional shape. "Transport roller errors" such as not being a perfect circle or being eccentric are one of the causes of transport errors. In particular, transport roller errors cause variations in the actual transport amount in the first paper feed.

<FIG> shows a graph of errors in transport amount relative to rotation amount of the transport roller, when there is a transport roller error. In <FIG>, the horizontal axis is the rotation amount of the transport roller shaft, and the vertical axis is the error in transport amount caused by the transport roller error. Ideally, in terms of design, transport amount should also be constant for a constant transport amount for a constant rotation of the transport roller. However, in practice, due to transport errors, the transport amount for a given rotation amount varies more or less than the designed value within one cycle of one transport roller rotation. Therefore, even if the transport section <NUM> is instructed to feed the paper a constant distance of the first distance L1, if the transport roller starts rotating at different phases, then the amount actually transported by said instruction will be different from the instructed amount. In a configuration with a plurality of transport rollers as shown in <FIG>, the error waveform shown in <FIG> should be interpreted as a composite waveform of the errors in the transport amount caused by the transport roller errors of all of the plurality of transport rollers.

In the explanation of <FIG>, the following relationship is assumed to be true: <MAT> and n = <NUM>.

The angle P° is, by design, the rotation amount of the transport roller shaft corresponding to the transport of the first distance L1 and, in step S110, the TP recording control section 12a takes the current angle of the transport roller shaft as the standard angle of <NUM>° and rotates it by angle P° from there to perform the first paper feed. This corresponds to the transport instruction for the first distance L1. In the example in <FIG>, the positive error is predominant in the range angle <NUM>° to angle P°, thus, as a result of step S110, the actual transport amount is more than the first distance L1, contrary to the example in <FIG>.

If n = <NUM>, the total transport amount in steps S110, S130, and S <NUM> is twice the circumference length of the transport roller, that is, two revolutions of the transport roller. Therefore, in step S130, the TP recording control section 12a performs the second paper feed by rotating the transport roller shaft from angle P° at that position to angle (<NUM>° - P°). This corresponds to the transport instruction for the second distance L2. In step S150, the TP recording control section 12a performs the first paper feed by rotating the transport roller shaft from angle (<NUM>° - P°) at that time to angle <NUM>°. This corresponds to the transport instruction for the first distance L1. In the example in <FIG>, the negative error is predominant in the range angle (<NUM>° - P°) to angle <NUM>°, thus, as a result of step S150, the actual transport amount is less than the first distance L1, contrary to the example in <FIG>.

As can be seen from <FIG>, the second paper feed in step <NUM> results in the opposite relationship to the errors in the first paper feed in steps S110 and S150, and they can cancel each other out. In this embodiment, the first TP group <NUM> with boundary area <NUM>, which is affected by the error in the transport amount generated in the first paper feed of step S110, and the second TP group <NUM> with boundary area <NUM>, which is affected by the error in the transport amount generated in the first paper feed of step S150, are recorded onto the medium <NUM>. This makes it possible to evaluate both the first TP group <NUM> and the second TP group <NUM>. As a result, it is easier to obtain appropriate adjustment values without the influence of the transport roller errors.

In step S170, the adjustment value calculation section 12b of the control section <NUM> obtains reading data of the first TP group <NUM> and the second TP group <NUM>. In other words, the reading device <NUM> reads the medium <NUM> on which the first TP group <NUM> and the second TP group <NUM> are recorded and outputs reading data as a result of the reading to the recording device <NUM>. Thereby, the control section <NUM> can obtain the reading data of the first TP group <NUM> and the second TP group <NUM>. The format of the reading data output by the reading device <NUM> is not limited, and can be red, green, and blue (RGB) color image data, monochrome luminance data, or colorimetric values from other color coordinate system.

In step S180, the adjustment value calculation section 12b obtains the streak density for each TP 40a, 40b, 40c, 40d, and 40e from the reading data of the first TP group <NUM>, and calculates an approximate line of these streak densities. Similarly, the adjustment value calculation section 12b obtains the streak density for each TP 40a, 40b, 40c, 40d, and 40e from the reading data of the second TP group <NUM>, and calculates an approximate line of these streak densities.

<FIG> shows the streak density obtained from the reading result of the first TP group <NUM> recorded on the medium <NUM>. According to <FIG>, the streak density for each adjustment value <NUM>, +α, +<NUM>α, +<NUM>α, and +<NUM>α, that is, for each TP 40a, 40b, 40c, 40d, and 40e, is plotted by black circles in a graph with the vertical axis being streak density and the horizontal axis being adjustment value. Streak density is the brightness of the boundary area <NUM> for each TP. Streak density may be interpreted as the difference between the density of the patch outside the boundary area <NUM> and the density of the boundary area <NUM>. The streak density D0 is an ideal value of the streak density, and refers to a state in which there is no difference from the density of the patch, that is, substantially no black streaks or no white streaks are visible.

In the graph, the streak density below D0, that is, at the high density side of the graph, corresponds to the black streaks, and the streak density above D0, that is, at the low density side of the graph, corresponds to the white streaks. Such streak density can be said to represents a deviation amount between the first patch <NUM> and the second patch <NUM> in the transport direction D2. After obtaining the streak densities for each TP 40a, 40b, 40c, 40d, and 40e of the first TP group <NUM>, the adjustment value calculation section 12b calculates an approximate line for these streak densities. According to <FIG>, the approximate line F1 is calculated from the streak densities for each TP 40a, 40b, 40c, 40d, and 40e by the least-squares method.

<FIG> shows the streak density obtained from the reading result of the second TP group <NUM> recorded on the medium <NUM>. The interpretation of <FIG> is the same as in <FIG>, so common explanations are omitted. After obtaining the streak densities for each TP 40a, 40b, 40c, 40d, and 40e of the second TP group <NUM>, the adjustment value calculation section 12b calculates an approximate line for these streak densities. According to <FIG>, the approximate line F2 is calculated from the streak densities for each TP 40a, 40b, 40c, 40d, and 40e by the least-squares method.

In step S190, the adjustment value calculation section 12b obtains β1 as an adjustment value when the streak density of the approximate line F1 is D0. According to <FIG>, the adjustment value β1 is larger than +2α and smaller than +3α. The adjustment value β1 is the adjustment value for the first distance L1, which is derived by focusing on the recording results of the first TP group <NUM>. Similarly, the adjustment value calculation section 12b obtains β2 as an adjustment value when the streak density of the approximate line F2 is D0. According to <FIG>, the adjustment value β2 is larger than <NUM> and smaller than +α. The adjustment value β2 is an adjustment value for the first distance L1, which is derived by focusing on the recording results of the second TP group <NUM>.

As can be seen from the previous explanations, the adjustment value β1 is affected by the errors in the transport amount that occurred in the first paper feed in step S110. On the other hand, the adjustment value β2 is affected by the errors in the transport amount that occurred in the first paper feed in step S150. Therefore, the adjustment value calculation section 12b calculates and stores an adjustment value βav, which is the average of the adjustment values β1 and β2. By the above, the flowchart in <FIG> ends.

The adjustment value βav can be said to be an adjustment value that cancels out the errors in the transport amount that occur in the first paper feed in step S110 and the first paper feed instep S150 due to transport roller errors, and also optimizes the first paper feed by the transport section <NUM> to avoid generation of black streaks and white streaks as much as possible. In other words, the TP recording control of steps S100 to S160 is a process of recording a plurality of TP groups suitable for calculating such an adjustment value βav. Thereafter, during the recording process of an image selected arbitrarily by the user, the control section <NUM> adopts the adjustment value βav and instructs the transport section <NUM> to use the "first distance L1 + βav" as the paper feed amount each time. As a result, it is possible to obtain a favorable recording quality with no or almost no black or white streaks occurring in the boundary area between each band-sized image recorded on the medium <NUM> in each pass.

Some of the modifications included in this embodiment will be described. A case in which the circumference length of the transport roller is N times the first distance L1 will be explained. N is an integer of <NUM> or more. The fact that the circumference length of the transport roller is N times the first distance L1 naturally means that following relationship is true:
(circumference length of transport roller) > (first distance L1) In such a case, the control section <NUM> records, in the TP recording control, N sets of the TP groups, including the first TP group <NUM> and the second TP group <NUM>, at different positions in the transport direction D2 on the medium <NUM>.

<FIG> shows a flowchart of the TP recording control when the circumference length of the transport roller is N times the first distance L1. If the circumference length of the transport roller is N times the first distance L1, the control section <NUM> executes the flowchart of <FIG> instead of steps S100 to S160 of <FIG>. <FIG> shows a state in which a plurality of TP groups is recorded on the medium <NUM> by the recording head <NUM> in the TP recording control of <FIG>, from the same viewpoint as in <FIG>. For the interpretation of <FIG>, the interpretation of <FIG> will be applied appropriately, and explanations common to those of <FIG> will be omitted. In <FIG>, the description of the adjustment values for each TP 40a, 40b, 40c, 40d, and 40e is omitted, but this can be understood in the same way as in <FIG>. In the following description of <FIG> and <FIG>, it is assumed that N = <NUM> as an example.

In step S200, the TP recording control section 12a sets a variable i, which indicates the number of the TP group, to <NUM> as an initial value. In step S210, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM> to record a plurality of first patches of the i-th TP group onto the medium <NUM>. The i-th TP group in step S210 is the first TP group, so step S210 is the same process as step S100 in <FIG>.

In step S220, the TP recording control section 12a instructs the transport section <NUM> to transport the first distance L1 to perform the first paper feed. Step S220 is the same process as step S110 or step S150 in <FIG>. After step S220, in step S230, the TP recording control section 12a determines whether the number of the current variable i is equal to N. If the number i has not reached N, the process proceeds to step S240 according to the judgment "No" in step S230. If the number of i = N, the process proceeds to step S260 according to the judgment "Yes" in step S230.

In step S240, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM> to record a plurality of second patches of the i-th TP group and a plurality of first patches of the (i + <NUM>)th TP group onto the medium <NUM>. The printing method for the plurality of second patches in one TP group has already been described. In other words, the recording of the plurality of second patches of the i-th TP group and the recording of the plurality of first patches of the (i + <NUM>)th TP group are recorded simultaneously in a single pass. According to <FIG>, the path P2 causes the recording of the second patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e in the first TP group <NUM> and the recording of the first patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e in the second TP group <NUM>. In this way, as an exception, the TP recording control described in <FIG> and <FIG> has no second paper feed in this embodiment.

In step S250, the TP recording control section 12a increments the number of the variable i. In other words, the number of the variable i is updated by adding <NUM> to the current number of the variable i. After step S250, the first paper feed of step S220 is performed and the process proceeds to a decision of step S230. According to this process flow, as shown in <FIG>, after the pass P2 and then the first paper feed, the pass P3 causes the recording of the second patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e in the second TP group <NUM>, and the recording of the first patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e of the third TP group <NUM>. Similarly, after the pass P3 and then the first paper feed, the pass P4 is causes the recording of the second patches <NUM> for each TP <NUM> a, 40b, 40c, 40d, and 40e in the third TP group <NUM>, and the recording of the first patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e in the fourth TP group <NUM>.

In step S260, which is proceeded to from step S230, the TP recording control section 12a controls the carriage <NUM> and the recording head <NUM> to record a plurality of second patches of the i-th TP group onto the medium <NUM>. In other words, according to <FIG>, after the pass P4 and then the first paper feed, the pass <NUM> causes the recording of the second patches <NUM> for each TP 40a, 40b, 40c, 40d, and 40e in the fourth TP group <NUM>. "N", that is, the four TP groups <NUM>, <NUM>, <NUM>, and <NUM> shown in <FIG>, are TP groups that are all recorded in the same way, except for the recording position on the medium <NUM> in the transport direction D2. However, in each of the TP groups <NUM>, <NUM>, <NUM>, and <NUM>, the "actual transport amount" by the first paper feed in step S220, which is performed between the recording of the first patches <NUM> and the second patches <NUM>, is different due to the transport roller errors. Therefore, the densities of the boundary areas <NUM> are also different for each of the TP groups <NUM>, <NUM>, <NUM>, and <NUM>.

After step S260, the control section <NUM> should execute processes from step S170 and thereafter in <FIG>. In other words, the adjustment value calculation section 12b obtains reading data of the medium <NUM> on which the first TP group <NUM>, the second TP group <NUM>, the third TP group <NUM>, and the fourth TP group <NUM> are recorded. Then, an approximate line is calculated based on the streak density of the boundary area <NUM> of each TP of each of the first TP group <NUM>, the second TP group <NUM>, the third TP group <NUM>, and the fourth TP group <NUM>, an adjustment value is calculated from the calculated approximate lines for each of the first TP group <NUM>, the second TP group <NUM>, the third TP group <NUM>, and the fourth TP group <NUM>, an average value of the adjustment values is calculated from these adjustment values for each of the first TP group <NUM>, the second TP group <NUM>, the third TP group <NUM>, and the fourth TP group <NUM>, and then the calculated average value is stored as an adjustment value βav.

In the TP recording control, the control section <NUM> may record a "marker" indicating the location of the boundary area <NUM> together with the TP. Referring to <FIG>, the TP 40d of the second TP group <NUM> is recorded on the media <NUM> together with a marker pattern <NUM> outside the TP 40d. The marker pattern <NUM> is a specific example of a marker, and is a ruled line located near the boundary area <NUM> of the corresponding TP 40d and having a length component in the main scanning direction D1.

The TP recording control section 12a, for example, controls the recording head <NUM> at the timing of recording the first patch <NUM> of TP 40d of the second TP group <NUM>, and can record one of the marker patterns <NUM> to the outside of the first patch <NUM> using the nozzle <NUM> that is furthest upstream from amongst the nozzles <NUM> being used when the recording the first patch <NUM>, or a nozzle <NUM> one or two nozzles downstream from that nozzle <NUM>. Similarly, the TP recording control section 12a can record, at the timing of recording the second patch <NUM> of the second TP of the TP40d group <NUM>, one of the marker patterns <NUM> to the outside of the second patch <NUM> using the nozzle <NUM> that is further downstream from amongst the nozzles <NUM> being used when recording the second patch <NUM>, or a nozzle <NUM> on one or two nozzles upstream from that nozzle <NUM>.

Although not illustrated in all of the TPs, needless to say, a marker such as the marker pattern <NUM> can be recorded in the same way for all of the TPs 40a, 40b, 40c, 40d, and 40e shown in <FIG> and <FIG>. The fact that the marker pattern <NUM> is recorded with the TPs enables the adjustment value calculation section 12b to efficiently and accurately obtain the streak density of the boundary area <NUM> for each TP from the reading data, by using the marker pattern <NUM> for each TP as a landmark when the reading data of multiple TP groups is acquired.

The marker pattern <NUM> is also useful when the user visually evaluates the multiple TP groups recorded on the medium <NUM>. The user can recognize the position near the marker pattern <NUM> in the TPs as the boundary area <NUM> and determine whether the black or white streaks occur in the boundary area <NUM>. When the user visually evaluates the TP groups, the user selects a TP of good image quality with the least noticeable black and white streaks for each TP group, and inputs the selection result to the control section <NUM> through the operation section <NUM>. The adjustment value calculation section 12b may recognizes the adjustment value corresponding to the TP selected by the user as an appropriate adjustment value for each TP group. Then, the average value of such appropriate adjustment values for each TP group is obtained, and this average value can be used as the adjustment value βav.

The marker to be recorded with the TP should appropriately indicate the location of the boundary area <NUM> in the TP. Therefore, in addition to ruled lines such as the marker patterns <NUM>, various other forms of maker can be considered, such as marks of specific shapes or colors, specific character strings, and so on.

As described above, according to this embodiment, the recording device <NUM> includes a recording head <NUM> that has a nozzle array with a plurality of nozzles <NUM> arranged in a predetermined nozzle alignment direction D3, the nozzles being configured to eject liquid onto a medium <NUM>, and that ejects liquid while moving in a first direction that intersects the nozzle alignment direction D3 to perform recording; a transport section <NUM> that has a transport roller configured to rotate to transport the medium <NUM> and that transport the medium <NUM> in a second direction that intersects the first direction; and a control section <NUM> that controls recording by the recording head <NUM> and transport by the transport section <NUM>. A circumference length of the transport roller is different from a nozzle array length which is a length of the nozzle array in the second direction. The control section <NUM> performs TP recording control to record, on the medium <NUM>, a group of TPs, in which a plurality of TPs including a first patch <NUM> and a second patch42 with different positions in the second direction are arranged in the first direction and in which an amount of liquid ejected for a boundary area <NUM> between the first patch <NUM> and the second patch <NUM> is different in the first direction for each TP. The control section <NUM>, in the TP recording control, records a first TP group <NUM> and a second TP group <NUM>, which are the TP groups, at different positions in the second direction onto the medium <NUM>, transports the medium <NUM> by a first distance L1 based on the nozzle array length as a transport between the recording of the first patch <NUM> and the second patch <NUM> of the TP, and transports the medium <NUM> by a second distance L2, which is a difference between an integral multiple (n times) of the circumference length and twice the first distance L1, as a transport between the recording of the second patch <NUM> of the first TP group <NUM> and the recording of the first patch <NUM> of the second TP group <NUM>.

Since the circumference length of the transport roller is different from the nozzle array length, the actual transport amount of transport in response to the instruction for the first distance L1 based on the nozzle array length can easily vary due to the transport roller errors. In this embodiment, in such a situation, the first TP group <NUM> and the second TP group <NUM> are recorded at different positions in the second direction as described above. By recording the TP, it can be said that the effect of transport roller errors can now be eliminated as much as possible to obtain the correct transport volume adjustment value.

Further, according to this embodiment, when a plurality of the transport rollers is located along the second direction, the control section <NUM> sets the second distance L2 as the difference between a common multiple of circumference lengths of the plurality of transport rollers and twice the first distance L1. If there is more than one transport roller, then the transport rollers are regarded as one virtual transport roller. In other words, the control section <NUM> can calculate the second distance L2 by treating the common multiple of the circumference lengths of multiple transport rollers as the circumference length of one virtual transport roller. In this case, n = <NUM> basically. However, in some cases, the value of n may be higher than <NUM>, and the second distance L2 may be obtained by following formula: <MAT>.

Since two times the least common multiple and three times the least common multiple are still common multiples, the second distance L2 is ultimately obtained by the same formula: <MAT>.

According to this configuration, even if the transport section <NUM> has a plurality of transport rollers, the TPs can be recorded to eliminate the effects of errors in each transport roller, which helps to obtain the correct adjustment value of the transport amount.

According to this embodiment, when the circumference length of the transport roller is N times the first distance L1 (where N is an integer of <NUM> or more), the control section <NUM> may record N number of TP groups, including the first TP group <NUM> and the second TP group <NUM>, at different positions in the second direction on the medium <NUM> in the TP recording control. According to the above configuration, the N number of TP groups can be recorded in the process of making one rotation of the transport roller by eliminating the transport of the second distance L2 as an exception and executing transport by instructing the first distance L1 N number of times. Since the transport errors caused by the transport roller errors vary even within one cycle of the transport roller, recording more TP groups will lead to obtaining more appropriate adjustment values.

According to this embodiment, the control section <NUM> may record the marker indicating the location of the boundary area <NUM> together with the TP in the TP recording control. According to the above configuration, the markers, which indicate the location of the boundary area <NUM>, will improve efficiency and accuracy when the control section <NUM> detects the position and the density of the boundary area <NUM> from the reading data of the TP group, or when the user visually evaluates the boundary area <NUM>. This avoids that the control section <NUM> wastefully detects the position and the density of the boundary areas <NUM>, saving processing time and memory consumption.

According to this embodiment, in the TP recording control, the control section <NUM> may record a plurality of TPs forming a TP group at equal intervals in the first direction. Assuming that the difference in positions in the first direction is also one of the causes that affect the density of the TPs on the medium <NUM>, then when calculating the adjustment value for each TP group from the approximate line of the streak density in the boundary area <NUM> of each TP, the accuracy of the calculated adjustment value is better if the TPs are equally spaced in the first direction.

This embodiment discloses various categories of embodiments, including not only things such as recording devices and systems, but also methods they execute, and programs <NUM> that cause a processor to execute the methods. For example, in a recording method of the recording device <NUM>,the recording device <NUM> has a recording head <NUM> that has a nozzle array with a plurality of nozzles <NUM> arranged in a predetermined nozzle alignment direction D3, the nozzles being configured to eject liquid onto a medium <NUM>, and that ejects liquid while moving in a first direction that intersects the nozzle alignment direction D3 to perform recording; a transport section <NUM> having a transport roller that rotates to transport the medium <NUM> and transport the medium <NUM> in a second direction that intersects the first direction, wherein a circumference length of the transport roller is different from a nozzle array length, which is a length of the nozzle array in the second direction, the recording method includes a TP recording step for recording, on the medium <NUM>, a group of TPs, in which a plurality of TPs including a first patch <NUM> and a second patch <NUM> with different positions in the second direction are arranged in the first direction, and in which an amount of liquid ejected for a boundary area <NUM> between the first patch <NUM> and the second patch <NUM> is different for each TP in the first direction. In the TP recording step, the recording method records on the medium <NUM> a first TP group <NUM> and a second TP group <NUM>, which are TP groups, at different positions in the second direction, transports by a first distance L1 based on the nozzle array length as a transport between the recording of the first patch <NUM> and the second patch <NUM> of the TP, and transports by a second distance L2, which is a difference between an integer multiple of the circumference length and two times the first distance L1, as a transport between the recording of the second patch <NUM> of the first TP group <NUM> and the recording of the first patch <NUM> of the second TP group <NUM>.

In the previous explanation, when recording TP groups in which the amount of liquid ejected for the boundary areas <NUM> between the first patches <NUM> and the second patches <NUM> is different for each TP 40a, 40b, 40c, 40d, and 40e in the first direction, the control section <NUM> differs the positional relationship between the first patches <NUM> and the second patches <NUM> in the second direction using the adjustment values for each TP 40a, 40b, 40c, 40d, and 40e. However, the method of recording the TP groups where the amount of liquid ejected to the boundary areas <NUM> differs for each TP 40a, 40b, 40c, 40d, and 40e in the first direction is not limited to this type of position adjustment.

For example, the control section <NUM> makes the positional relationship between the first patches <NUM> and the second patched <NUM> in the second direction the same for all of the plurality of TPs 40a, 40b, 40c, 40d, and 40e in one TP group. That is, when recording the second patches <NUM> as described above, no region of unused nozzles <NUM> is provided. Then, the control section <NUM> varies the amount of the ink ejection to the boundary area <NUM> for each TP 40a, 40b, 40c, 40d, and 40e according to the adjustment value for each TP 40a, 40b, 40c,40d, and 40e. For example, a TP with a smaller adjustment value will reduce the number of dots ejected by the nozzles <NUM> that are predetermined as the nozzles <NUM> to be used for recording the boundary area <NUM>, and a TP with a larger adjustment value will increase the number of dots ejected by the nozzles <NUM> used for recording the boundary area <NUM>. According to this configuration, the adjustment value is not an adjustment value for the transport amount of the transport section <NUM>, but an adjustment value for the amount of ejection with respect to the nozzles <NUM> used to record the boundary area <NUM>.

Claim 1:
A recording device (<NUM>) comprising:
a recording head (<NUM>) that has a nozzle array (<NUM>) with a plurality of nozzles (<NUM>) for ejecting liquid onto a medium (<NUM>), the nozzles being arranged in a predetermined nozzle alignment direction (D3), and that ejects liquid while moving in a first direction (D1) that intersects the nozzle alignment direction (D3) to perform recording;
a transport section (<NUM>) that has a transport roller (17a) configured to rotate to transport the medium (<NUM>) and that transports the medium in a second direction (D2) that intersects the first direction (D1); and
a control section (<NUM>) that controls recording by the recording head (<NUM>) and transport by the transport section (<NUM>), wherein
a circumference length of the transport roller (17a) is different from a nozzle array length, which is a length of the nozzle array in the second direction (D2),
the control section (<NUM>)
performs TP recording control to record, on the medium, a group of test patterns, in which a plurality of test patterns including a first patch (<NUM>) and a second patch (<NUM>) with different positions in the second direction (D2) are arranged in the first direction (D1) and an amount of liquid ejected for a boundary area (<NUM>) between the first patch (<NUM>) and the second patch (<NUM>) is different in the first direction (D1) for each test pattern and,
in the TP recording control,
records a first test pattern group (<NUM>) and a second test pattern group (<NUM>), which are the test pattern groups, at different positions in the second direction (D2) on the medium,
transports the medium (<NUM>) by a first distance (L1) based on the nozzle array length as a transport between the recording of the first patch (<NUM>) and the second patch (<NUM>) of the test pattern, and
transports the medium (<NUM>) by a second distance (L2), which is a difference between an integer multiple of the circumference length and two times the first distance (L1), as a transport between the recording of the second patch (<NUM>) of the first test pattern group (<NUM>) and the recording of the first patch (<NUM>) of the second test pattern group (<NUM>).