JP2008119951A - Conveyance amount correction evaluating method, conveyance amount correction evaluating device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate the correction result at conveying a medium by making the correction of a target conveyance amount using the correction value for correcting the conveyance error of DC component. <P>SOLUTION: A conveyance amount correction evaluating method includes the step of making a head record a pattern for checking the conveyance amount of the medium while conveying the medium to the head in the conveyance direction by rotating a roller according to the target conveyance amount used as a target, the step of calculating the correction value corresponding to the relative position of the head and the medium from the checking pattern, the step of conveying the medium from the recording position of the 1st pattern by the amount corresponding to one round of the roller while correcting the target conveyance amount using the correction value corresponding to the relative position and of making the head record the 2nd pattern and the step of evaluating the result of the target conveyance amount correction made with the correction value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a carry amount correction evaluation method, a carry amount correction evaluation apparatus, and a program.

  The DC component transport error is a transport error that occurs when the transport roller rotates once to transport the paper in the transport direction. This DC component transport error is considered to be caused by the fact that the peripheral length of the transport roller varies from one printer to another due to manufacturing errors or the like. That is, the DC component transport error is a transport error that occurs because the designed peripheral length of the transport roller is different from the actual peripheral length of the transport roller.

The actual DC component transport error varies depending on the total transport amount of paper due to the influence of paper friction and the like. That is, the DC component transport error has a different value depending on the relative position of the paper with respect to the printer. In order to cancel the DC component transport error, a correction value corresponding to the relative position of the paper with respect to the printer is obtained. Then, a correction value corresponding to the relative position of the sheet with respect to the printer is used, the conveyance amount is corrected, and the sheet is conveyed.
JP-A-5-96796 JP 2003-11345 A

  Even if the transport is performed by correcting the DC component transport error using the correction value, it is necessary to evaluate how accurately the transport is performed by correcting the transport amount.

  The present invention has been made in view of such circumstances, and a correction result when the medium is conveyed by correcting the target conveyance amount using the correction value for correcting the DC component conveyance error. The purpose is to evaluate.

The main invention for achieving the above object is:
A measurement pattern for recording on the head a measurement pattern for confirming the conveyance amount of the medium while rotating the roller according to the target conveyance amount as a target and conveying the medium in the conveyance direction with respect to the head. Recording step;
A correction value for correcting the target transport amount when transporting the medium based on the measurement pattern, and a correction value for determining a correction value associated with a relative position between the head and the medium A decision step;
The first pattern is recorded on the head, and the medium is equivalent to one rotation of the roller from the recording position of the first pattern while correcting the target transport amount using the correction value corresponding to the relative position. A second pattern recording step in which the head is transported by a transport amount, and the head records a second pattern;
An evaluation step of evaluating a result of the correction of the target transport amount using the correction value based on the distance between the first pattern and the second pattern;
Is a conveyance amount correction evaluation method including
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

At least the following matters will become clear from the description of the present specification and the accompanying drawings.
A measurement pattern for recording on the head a measurement pattern for confirming the conveyance amount of the medium while rotating the roller according to the target conveyance amount as a target and conveying the medium in the conveyance direction with respect to the head. Recording step;
A correction value for correcting the target transport amount when transporting the medium based on the measurement pattern, and a correction value for determining a correction value associated with a relative position between the head and the medium A decision step;
The first pattern is recorded on the head, and the medium is equivalent to one rotation of the roller from the recording position of the first pattern while correcting the target transport amount using the correction value corresponding to the relative position. A second pattern recording step in which the head is transported by a transport amount, and the head records a second pattern;
An evaluation step of evaluating a result of the correction of the target transport amount using the correction value based on the distance between the first pattern and the second pattern;
Conveyance correction evaluation method including
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

  In this transport amount correction evaluation method, it is preferable that the second pattern recording step includes a step of recording a plurality of sets of the first pattern and the second pattern on the medium. The second pattern recording step preferably includes a step of recording another set of first patterns between the set of the first pattern and the second pattern. Further, the second pattern recording step includes a step of recording the other pattern of the first pattern at a division position when the interval between the first pattern and the second pattern is equally divided into a plurality of portions. Is desirable. The evaluation step includes a step of evaluating that the correction of the target transport amount is properly performed when the absolute value of the distance between the first pattern and the second pattern is smaller than a predetermined threshold value. It is desirable to include.

Further, the evaluation step evaluates that the correction of the target transport amount is properly performed when the sum of absolute values of the distances between the first pattern and the second pattern is smaller than a predetermined threshold value. It is desirable to include a step. Further, the first pattern and the second pattern may be rectangular patterns. The evaluation step may include a step of evaluating a result of the correction of the target carry amount based on the degree of overlap between the first pattern and the second pattern.
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

A correction value for correcting a target transport amount when transporting the medium, based on a measurement pattern for confirming the transport amount of the medium, and between the medium and the head on which the confirmation pattern is recorded. Find the correction value associated with the relative position,
Recording is performed after the first pattern and the correction value are used to correct the target conveyance amount, and then conveyed from the recording position of the first pattern by a conveyance amount corresponding to one rotation of the roller that conveys the medium. A transport amount correction evaluation apparatus that evaluates a correction result using the correction value based on a distance from the second pattern.
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

A program for operating the conveyance amount correction evaluation apparatus,
Rotating the roller according to a target transport amount to be a target and transporting the medium in the transport direction with respect to the head, and recording a measurement pattern for confirming the transport amount of the medium on the head;
Obtaining a correction value for correcting the target transport amount when transporting the medium based on the measurement pattern, the correction value being associated with the relative position between the head and the medium; ,
The first pattern is recorded on the head, and the medium is equivalent to one rotation of the roller from the recording position of the first pattern while correcting the target transport amount using the correction value corresponding to the relative position. Transporting with a transport amount to be recorded, and causing the head to record a second pattern;
Evaluating a correction result of the target transport amount using the correction value based on a distance between the first pattern and the second pattern;
A program for causing the transport amount correction evaluation apparatus to perform
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

=== First Embodiment ===
<Inkjet printer configuration>
FIG. 1 is a block diagram of the overall configuration of the printer 1. FIG. 2A is a schematic diagram of the overall configuration of the printer 1. FIG. 2B is a cross-sectional view of the overall configuration of the printer 1. Hereinafter, a basic configuration of the printer will be described.

  The printer 1 includes a transport unit 20, a carriage unit 30, a head unit 40, a detector group 50, and a controller 60. The printer 1 that has received print data from the computer 110, which is an external device, controls each unit (the conveyance unit 20, the carriage unit 30, and the head unit 40) by the controller 60. The controller 60 controls each unit based on the print data received from the computer 110 and prints an image on paper. The situation in the printer 1 is monitored by a detector group 50, and the detector group 50 outputs a detection result to the controller 60. The controller 60 controls each unit based on the detection result output from the detector group 50.

  The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined direction (hereinafter referred to as a transport direction). The transport unit 20 includes a paper feed roller 21, a transport motor 22 (also referred to as a PF motor), a transport roller 23, a platen 24, and a paper discharge roller 25. The paper feed roller 21 is a roller for feeding the paper inserted into the paper insertion slot into the printer. The transport roller 23 is a roller that transports the paper S fed by the paper feed roller 21 to a printable area, and is driven by the transport motor 22. The platen 24 supports the paper S being printed. The paper discharge roller 25 is a roller for discharging the paper S to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area. The paper discharge roller 25 rotates in synchronization with the transport roller 23.

  When the transport roller 23 transports the paper S, the paper S is sandwiched between the transport roller 23 and the driven roller 26. Thereby, the posture of the paper S is stabilized. On the other hand, when the paper discharge roller 25 transports the paper S, the paper S is sandwiched between the paper discharge roller 25 and the driven roller 27.

  The carriage unit 30 is for moving (also referred to as “scanning”) the head in a predetermined direction (hereinafter referred to as a moving direction). The carriage unit 30 includes a carriage 31 and a carriage motor 32 (also referred to as a CR motor). The carriage 31 can reciprocate in the moving direction and is driven by a carriage motor 32. Further, the carriage 31 detachably holds an ink cartridge that stores ink.

  The head unit 40 is for ejecting ink onto paper. The head unit 40 includes a head 41 having a plurality of nozzles. Since the head 41 is provided on the carriage 31, when the carriage 31 moves in the movement direction, the head 41 also moves in the movement direction. Then, by intermittently ejecting ink while the head 41 is moving in the moving direction, dot lines (raster lines) along the moving direction are formed on the paper.

  The detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder 51 detects the position of the carriage 31 in the moving direction. The rotary encoder 52 detects the rotation amount of the transport roller 23. The paper detection sensor 53 detects the position of the leading edge of the paper being fed. The optical sensor 54 detects the presence or absence of paper by a light emitting unit and a light receiving unit attached to the carriage 31. The optical sensor 54 can detect the position of the edge of the paper while being moved by the carriage 31 to detect the width of the paper. The optical sensor 54 also detects the leading end (the end on the downstream side in the transport direction, also referred to as the upper end) and the rear end (the end on the upstream side in the transport direction, also referred to as the lower end) depending on the situation. it can.

  The controller 60 is a control unit (control unit) for controlling the printer. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 transmits and receives data between the computer 110 which is an external device and the printer 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

<About nozzle>
FIG. 3 is an explanatory diagram showing the arrangement of nozzles on the lower surface of the head 41. On the lower surface of the head 41, a black ink nozzle group K, a cyan ink nozzle group C, a magenta ink nozzle group M, and a yellow ink nozzle group Y are formed. Each nozzle group includes 90 nozzles that are ejection openings for ejecting ink of each color.

  The plurality of nozzles of each nozzle group are aligned at a constant interval (nozzle pitch: k · D) along the transport direction. Here, D is the minimum dot pitch in the carrying direction (that is, the interval at the highest resolution of dots formed on the paper S). K is an integer of 1 or more. For example, when the nozzle pitch is 90 dpi (1/90 inch) and the dot pitch in the transport direction is 720 dpi (1/720 inch), k = 8.

  The nozzles in each nozzle group are assigned a smaller number as the nozzles on the downstream side (# 1 to # 90). That is, the nozzle # 1 is located downstream of the nozzle # 90 in the transport direction. It should be noted that the optical sensor 54 described above is located at substantially the same position as the nozzle # 90 on the most upstream side with respect to the position in the paper transport direction.

  Each nozzle is provided with an ink chamber (not shown) and a piezoelectric element. By driving the piezo element, the ink chamber expands and contracts, and ink droplets are ejected from the nozzle.

<Conveying paper>
FIG. 4 is an explanatory diagram of the configuration of the transport unit 20.
The transport unit 20 drives the transport motor 22 by a predetermined drive amount based on a transport command from the controller 60. The conveyance motor 22 generates a driving force in the rotation direction according to the commanded driving amount. The transport motor 22 rotates the transport roller 23 using this driving force. That is, when the transport motor 22 generates a predetermined drive amount, the transport roller 23 rotates by a predetermined rotation amount. When the transport roller 23 rotates with a predetermined rotation amount, the paper is transported with a predetermined transport amount.

The carry amount of the paper is determined according to the rotation amount of the carry roller 23. Here, it is assumed that when the transport roller 23 makes one rotation, the paper is transported by 1 inch (that is, the peripheral length of the transport roller 23 is 1 inch). For this reason, when the transport roller 23 rotates 1/4, the paper is transported by 1/4 inch.
Therefore, if the rotation amount of the conveyance roller 23 can be detected, the conveyance amount of the paper can also be detected. Therefore, a rotary encoder 52 is provided to detect the rotation amount of the transport roller 23.

The rotary encoder 52 includes a scale 521 and a detection unit 522. The scale 521 has a large number of slits provided at predetermined intervals. The scale 521 is provided on the transport roller 23. That is, the scale 521 rotates together when the transport roller 23 rotates. When the transport roller 23 rotates, the slits of the scale 521 sequentially pass through the detection unit 522. The detection unit 522 is provided to face the scale 521 and is fixed to the printer main body side. The rotary encoder 52 outputs a pulse signal each time a slit provided in the scale 521 passes through the detection unit 522. Since the slits provided in the scale 521 sequentially pass through the detection unit 522 according to the rotation amount of the conveyance roller 23, the rotation amount of the conveyance roller 23 is detected based on the output of the rotary encoder 52. When the paper is transported in an amount of 1 inch, the controller 60 drives the transport motor 22 until the rotary encoder 52 detects that the transport roller 23 has rotated once. As described above, the controller 60 drives the carry motor 22 until the rotary encoder 52 detects that the rotation amount is in accordance with the target carry amount (target carry amount), and sets the paper to the target carry amount. Transport.

<About transport error>
By the way, the rotary encoder 52 directly detects the rotation amount of the transport roller 23, and strictly speaking, does not detect the transport amount of the paper S. For this reason, when the rotation amount of the transport roller 23 and the transport amount of the paper S do not match, the rotary encoder 52 cannot accurately detect the transport amount of the paper S, and a transport error (detection error) occurs. There are two types of transport errors: DC component transport errors and AC component transport errors.

  The DC component transport error is a predetermined amount of transport error that occurs when the transport roller rotates once. The DC component transport error is considered to be caused by the circumference of the transport roller 23 being different for each printer due to a manufacturing error or the like. That is, the DC component transport error is a transport error that occurs because the designed peripheral length of the transport roller 23 is different from the actual peripheral length of the transport roller 23. The DC component transport error is constant regardless of the start position when the transport roller 23 rotates once. However, the actual DC component transport error varies depending on the total transport amount of paper due to the influence of paper friction and the like (described later). In other words, the actual DC component transport error varies depending on the relative positional relationship between the paper S and the transport roller 23 (or the paper S and the head 41).

  The AC component transport error is a transport error according to the location of the peripheral surface of the transport roller used during transport. The AC component transport error varies depending on the location of the peripheral surface of the transport roller used during transport. That is, the AC component transport error varies depending on the rotation position of the transport roller at the start of transport and the transport amount.

  FIG. 5 is a graph for explaining the AC component transport error. The horizontal axis represents the rotation amount of the transport roller 23 from the reference rotation position. The vertical axis represents the transport error. If this graph is differentiated, a transport error that occurs when the transport roller is transporting at the rotational position can be derived. Here, the cumulative transport error at the reference position is zero, and the DC component transport error is also zero.

  When the transport roller 23 rotates 1/4 from the reference position, a transport error of δ_90 occurs, and the paper is transported by 1/4 inch + δ_90. However, if the transport roller 23 further rotates by 1/4, a transport error of -δ_90 occurs, and the paper is transported by 1/4 inch -δ_90.

There are three possible causes for the AC component transport error, for example.
First, the influence of the shape of the transport roller can be considered. For example, when the conveyance roller is elliptical or egg-shaped, the distance to the rotation center differs depending on the location of the circumferential surface of the conveyance roller. When the medium is transported at a portion where the distance to the rotation center is long, the transport amount with respect to the rotation amount of the transport roller increases. On the other hand, when the medium is transported at a portion where the distance to the rotation center is short, the transport amount with respect to the rotation amount of the transport roller is reduced.
Secondly, the eccentricity of the rotation shaft of the transport roller can be considered. Also in this case, the length to the center of rotation differs depending on the location of the peripheral surface of the transport roller. For this reason, even if the rotation amount of the conveyance roller is the same, the conveyance amount varies depending on the location of the circumferential surface of the conveyance roller.
Thirdly, a mismatch between the rotation axis of the transport roller and the center of the scale 521 of the rotary encoder 52 can be considered. In this case, the scale 521 rotates eccentrically. As a result, the amount of rotation of the transport roller 23 with respect to the detected pulse signal differs depending on the location of the scale 521 detected by the detection unit 522. For example, when the detected location of the scale 521 is away from the rotation axis of the conveyance roller 23, the rotation amount of the conveyance roller 23 with respect to the detected pulse signal decreases, and the conveyance amount decreases. On the other hand, when the detected location of the scale 521 is close to the rotation axis of the conveyance roller 23, the rotation amount of the conveyance roller 23 with respect to the detected pulse signal increases, and thus the conveyance amount increases.
Due to the above cause, the AC component transport error is substantially a sine curve as shown in FIG.

<Conveyance error to be corrected in the reference example>
FIG. 6 is a graph (conceptual diagram) of a transport error that occurs when transporting a paper having a size of 101.6 mm × 152.4 mm (4 inches × 6 inches). The horizontal axis of the graph indicates the total transport amount of paper. The vertical axis of the graph indicates the transport error. The dotted line in the figure is a graph of the DC component transport error. The AC component transport error can be obtained by subtracting the dotted line value (DC component transport error) in the drawing from the solid line value (total transport error) in the diagram. The AC component transport error is almost a sine curve regardless of the total paper transport amount. On the other hand, the DC component transport error indicated by the dotted line differs depending on the total transport amount of paper due to the influence of paper friction and the like.

  As already described, the AC component transport error varies depending on the location of the peripheral surface of the transport roller 23. For this reason, even when the same paper is transported, if the rotation position of the transport roller 23 at the start of transport is different, the transport error of the AC component is different, and therefore the total transport error (the transport error indicated by the solid line in the graph). ) Will be different. On the other hand, the DC component transport error is different from the AC component transport error and is not related to the location of the peripheral surface of the transport roller. Therefore, even if the rotational position of the transport roller 23 at the start of transport is different, the transport roller 23 The transport error (DC component transport error) that occurs when the motor rotates once is the same.

  Further, when trying to correct the AC component transport error, the controller 60 needs to detect the rotational position of the transport roller 23. However, in order to detect the rotational position of the transport roller 23, it is necessary to further provide an origin sensor in the rotary encoder 52, which increases costs.

  Therefore, in the correction of the carry amount of the reference example described below, the carry error of the DC component is corrected.

  On the other hand, the DC component transport error varies depending on the total transport amount of the paper (in other words, the relative positional relationship between the paper S and the transport roller 23) (see the dotted line in FIG. 6). For this reason, if more correction values can be prepared according to the position in the transport direction, the transport error can be finely corrected. Therefore, in the reference example, a correction value for correcting the DC component transport error is prepared for each 1/4 inch range, not for each 1 inch range corresponding to one rotation of the transport roller 23. .

<Overview>
FIG. 7 is a flowchart for determining a correction value for correcting the carry amount. FIG. 8A to FIG. 8C are explanatory diagrams of how the correction value is determined. These processes are performed in the inspection process of the printer manufacturing factory. Prior to this process, the inspector connects the assembled printer 1 to the computer 110 in the factory. A scanner 150 is also connected to the computer 110 in the factory, and a printer driver, a scanner driver, and a correction value acquisition program are installed in advance.

  First, the printer driver transmits print data to the printer 1, and the printer 1 prints the measurement pattern on the test sheet TS (S101, FIG. 8A). Next, the inspector sets the test sheet TS on the scanner 150, and the scanner driver causes the scanner 150 to read the measurement pattern and acquire image data (S102, FIG. 8B). A reference sheet is set in the scanner 150 together with the test sheet TS, and a reference pattern drawn on the reference sheet is also read together.

  Then, the correction value acquisition program analyzes the acquired image data and calculates a correction value (S103). Then, the correction value acquisition program transmits the correction data to the printer 1 and stores the correction value in the memory 63 of the printer 1 (FIG. 8C). The correction value stored in the printer reflects the conveyance characteristics of each printer.

  The printer storing the correction value is packed and delivered to the user. When the user prints an image with the printer, the printer conveys the paper based on the correction value and prints the image on the paper.

<Printing measurement pattern (S101)>
First, the measurement pattern printing will be described. Similar to normal printing, the printer 1 alternately repeats a dot formation process for forming dots by ejecting ink from the moving nozzles and a transport operation for transporting the paper in the transport direction, and the measurement pattern is printed on the paper. Print on. In the following description, the dot formation process is referred to as “pass”, and the nth dot formation process is referred to as “pass n”.

  FIG. 9 is an explanatory diagram of how the measurement pattern is printed. The size of the test sheet TS on which the measurement pattern is printed is 101.6 mm × 152.4 mm (4 inches × 6 inches).

  On the right side of the figure, a measurement pattern printed on the test sheet TS is shown. The left rectangle in the drawing indicates the position of the head 41 in each pass (relative position with respect to the test sheet TS). For convenience of explanation, the head 41 is depicted as moving with respect to the test sheet TS, but this figure shows the relative positional relationship between the head and the test sheet TS. The test sheet TS is intermittently conveyed in the conveyance direction.

  As the test sheet TS continues to be conveyed, the lower end of the test sheet TS passes through the conveyance roller 23. The position of the test sheet TS that faces the most upstream nozzle # 90 when the lower end of the test sheet TS passes the transport roller 23 is indicated by a dotted line in the drawing as an “NIP line”. That is, in the path in which the head 41 is above the NIP line in the figure, printing is performed with the test sheet TS sandwiched between the transport roller 23 and the driven roller 26 (also referred to as “NIP state”). Is called. In the drawing, in a path where the head 41 is below the NIP line, there is no test sheet TS between the transport roller 23 and the driven roller 26 (the test sheet TS is formed only by the paper discharge roller 25 and the driven roller 27). And is also referred to as “non-NIP state”).

The measurement pattern includes an identification code and a plurality of lines.
The identification code is an individual identification symbol for identifying each printer 1. This identification code is read together when the measurement pattern is read in S102, and is identified by the computer 110 by character recognition by OCR.
Each line is formed along the moving direction. Many lines are formed on the upper end side of the NIP line. Regarding the line on the upper end side from the NIP line, the i-th line in order from the upper end side is referred to as “Li”. Two lines are formed on the lower end side of the NIP line. Of the two lines on the lower end side of the NIP line, the upper end side line is called Lb1, and the lower end side line (lowermost line) is called Lb2. A specific line is formed longer than the other lines. For example, the line L1, the line L13, and the line Lb2 are formed longer than the other lines. These lines are formed as follows.

  First, after the test sheet TS is conveyed to a predetermined printing start position, ink droplets are ejected from only the nozzle # 90 in pass 1 to form a line L1. After pass 1, the controller 60 rotates the transport roller 23 by 1/4 to transport the test sheet TS by about 1/4 inch. After transport, in pass 2, ink droplets are ejected only from nozzle # 90, and line L2 is formed. Thereafter, the same operation is repeated, and the lines L1 to L20 are formed at intervals of about 1/4 inch. Thus, the lines L1 to L20 located on the upper end side of the NIP line are formed by the most upstream nozzle # 90 among the nozzles # 1 to # 90. Thereby, as many lines as possible can be formed on the test sheet TS in the NIP state. The lines L1 to L20 are formed only by the nozzle # 90, but in the pass for printing the identification code, nozzles other than the nozzle # 90 are also used when printing the identification code.

  After the lower end of the test sheet TS passes through the transport roller 23, ink droplets are ejected only from the nozzle # 90 in pass n to form a line Lb1. After pass 1, the controller 60 rotates the transport roller 23 once to transport the test sheet TS by about 1 inch. After transport, in pass n + 1, ink droplets are ejected only from nozzle # 3 to form line Lb2. If nozzle # 1 is used, the distance between line Lb1 and line Lb2 becomes very narrow (about 1/90 inch), and it becomes difficult to measure the distance between line Lb1 and line Lb2 later. . For this reason, here, by forming the line Lb2 using the nozzle # 3 located upstream in the transport direction from the nozzle # 1, the distance between the line Lb1 and the line Lb2 is widened to facilitate measurement.

  By the way, when the test sheet TS is conveyed ideally, the interval between the lines L1 to L20 should be exactly 1/4 inch. However, if there is a conveyance error, the line interval does not become 1/4 inch. If the test sheet TS is transported more than the ideal transport amount, the line interval increases. Conversely, when the test sheet TS is transported less than the ideal transport amount, the line interval is narrowed. That is, the interval between two lines reflects a transport error in a transport process performed between a path in which one line is formed and a path in which the other line is formed. For this reason, if the distance between two lines is measured, it is possible to measure a transport error in a transport process performed between a path in which one line is formed and a path in which the other line is formed. .

  Similarly, the distance between the line Lb1 and the line Lb2 is such that when the test sheet TS is transported ideally (more precisely, when the ink ejection of the nozzle # 90 and the nozzle # 3 is the same). It should be exactly 3/90 inches. However, if there is a transport error, the line spacing does not become 3/90 inches. For this reason, it is considered that the interval between the line Lb1 and the line Lb2 reflects a transport error in the transport process in the non-NIP state. For this reason, if the distance between the line Lb1 and the line Lb2 is measured, it is possible to measure the transport error in the transport process in the non-NIP state.

<Reading pattern (S102)>
<Scanner configuration>
First, the configuration of the scanner 150 used for reading the measurement pattern will be described.
FIG. 10A is a longitudinal sectional view of the scanner 150. FIG. 10B is a top view of the scanner 150 with the upper lid 151 removed.

  The scanner 150 includes an upper cover 151, a document table glass 152 on which the document 5 is placed, a reading carriage 153 that moves in the sub-scanning direction while facing the document 5 through the document table glass 152, and a sub-scanning of the reading carriage 153. A guide unit 154 for guiding in the direction, a moving mechanism 155 for moving the reading carriage 153, and a scanner controller (not shown) for controlling each unit in the scanner 150 are provided. The reading carriage 153 receives an exposure lamp 157 for irradiating the original 5 with light, a line sensor 158 for detecting a line image in the main scanning direction (a direction perpendicular to the paper surface in FIG. 10A), and reflected light from the original 5. An optical system 159 for guiding to the line sensor 158 is provided. A broken line inside the reading carriage 153 in the drawing indicates a locus of light.

  When reading the image of the document 5, the operator opens the upper cover 151, places the document 5 on the document table glass 152, and closes the upper cover 151. Then, the scanner controller moves the reading carriage 153 along the sub-scanning direction with the exposure lamp 157 emitting light, and reads the image on the surface of the document 5 by the line sensor 158. The scanner controller transmits the read image data to the scanner driver of the computer 110, whereby the computer 110 acquires the image data of the document 5.

<Reading position accuracy>
As will be described later, in the reference example, the scanner 150 reads the measurement pattern of the test sheet TS and the reference pattern of the reference sheet with a resolution of 720 dpi (main scanning direction) × 720 dpi (sub-scanning direction). For this reason, in the following description, description will be made on the assumption that an image is read at a resolution of 720 × 720 dpi.

  FIG. 11 is a graph of the error in the reading position of the scanner. The horizontal axis of the graph indicates the reading position (theoretical value) (that is, the horizontal axis of the graph indicates the position (theoretical value) of the reading carriage 153). The vertical axis of the graph represents the reading position error (difference between the theoretical value of the reading position and the actual reading position). For example, when the reading carriage 153 is moved by 1 inch (= 25.4 mm), an error of about 60 μm occurs.

  If the theoretical value of the reading position matches the actual reading position, a pixel that is 720 pixels away from the pixel indicating the reference position (position where the reading position is zero) in the sub-scanning direction is exactly 1 inch from the reference position. It should show an image at a distant location. However, when an error in the reading position as shown in the graph occurs, a pixel that is 720 pixels away from the pixel that indicates the reference position in the sub-scanning direction is a position that is further 60 μm away from a position that is 1 inch away from the reference position. An image will be shown.

  If the slope of the graph is zero, images should be read at equal intervals every 1/720 inch. However, when the slope of the graph is positive, images are read at intervals longer than 1/720 inch. Further, when the slope of the graph is negative, images are read at intervals shorter than 1/720 inch.

  As a result, even if the measurement pattern lines are formed at equal intervals, the line images on the image data do not have equal intervals in a state where there is an error in the reading position. As described above, in a state where there is an error in the reading position, the line position cannot be accurately measured simply by reading the measurement pattern.

  Therefore, in the reference example, when the test sheet TS is set and the measurement pattern is read by the scanner, the reference sheet is set and the reference pattern is also read.

<Reading measurement pattern and reference pattern>
FIG. 12A is an explanatory diagram of the reference sheet SS. FIG. 12B is an explanatory diagram showing a state in which the test sheet TS and the reference sheet SS are set on the platen glass 152.

  The size of the reference sheet SS is 10 mm × 300 mm, and the reference sheet SS has a long and thin shape. In the reference sheet SS, a large number of lines are formed as reference patterns at intervals of 36 dpi. Since the reference sheet SS is repeatedly used, it is not a paper but a PET film. The reference pattern is formed with high accuracy by laser processing.

  By using a jig (not shown), the test sheet TS and the reference sheet SS are set at predetermined positions on the platen glass 152. The reference sheet SS is set on the platen glass 152 so that the long side thereof is parallel to the sub-scanning direction of the scanner 150, that is, each line of the reference sheet SS is parallel to the main scanning direction of the scanner 150. The A test sheet TS is set next to the reference sheet SS. The test sheet TS is set on the platen glass 152 so that the long side is parallel to the sub-scanning direction of the scanner 150, that is, the lines of the measurement pattern are parallel to the main scanning direction.

  With the test sheet TS and the reference sheet SS set in this way, the scanner 150 reads the measurement pattern and the reference pattern. At this time, due to the influence of the error in the reading position, the image of the measurement pattern in the reading result becomes a distorted image as compared with the actual measurement pattern. Similarly, the image of the reference pattern is also distorted compared to the actual reference pattern.

  Note that the measurement pattern image in the reading result is affected not only by the error of the reading position but also by the conveyance error of the printer 1. On the other hand, since the reference pattern is formed at equal intervals irrespective of the transport error of the printer, the image of the reference pattern is affected by the error in the reading position of the scanner 150. It is not affected by the error.

  Therefore, when calculating the correction value based on the measurement pattern image, the correction value acquisition program cancels the influence of the reading position error in the measurement pattern image based on the reference pattern image.

<Calculation of correction value (S103)>
Before describing the correction value calculation, the image data acquired from the scanner 150 will be described. The image data is composed of a plurality of pixel data. Each pixel data indicates the gradation value of the corresponding pixel. If the reading error of the scanner is ignored, each pixel corresponds to a size of 1/720 inch × 1/720 inch. An image (digital image) is configured with such a pixel as a minimum structural unit, and the image data is data indicating such an image.

  FIG. 13 is a flowchart of the correction value calculation process in S103. The computer 110 executes each process according to the correction value acquisition program. That is, the correction value acquisition program has a code for causing the computer 110 to execute each process.

<Image Division (S131)>
First, the computer 110 divides the image indicated by the image data acquired from the scanner 150 into two (S131).
FIG. 14 is an explanatory diagram of image division (S131). On the left side of the drawing, an image indicated by the image data acquired from the scanner is drawn. The divided image is drawn on the right side in the figure. In the following description, the left-right direction (horizontal direction) in the figure is called the x direction, and the up-down direction (vertical direction) in the figure is called the y direction. Each line in the reference pattern image is substantially parallel to the x direction, and each line in the measurement pattern image is substantially parallel to the y direction.

  The computer 110 divides the image into two by extracting an image in a predetermined range from the image of the reading result. By dividing the image of the reading result into two, one image shows the image of the reference pattern and the other image shows the image of the measurement pattern. The reason for dividing in this way is that the reference sheet SS and the test sheet TS may be separately inclined and set in the scanner 150, so that the inclination correction (S133) is performed separately.

<Detection of Inclination of Each Image (S132)>
Next, the computer 110 detects the inclination of the image (S132).
FIG. 15A is an explanatory diagram illustrating a state where the inclination of the image of the measurement pattern is detected. The computer 110 extracts, from the image data, the KX2th pixel from the left and the KY1st to JY pixels from the top. Similarly, the computer 110 extracts from the image data the KX3th pixel from the left and the KY1 to JY pixels from the top. The parameters KX2, KX3, KY1, and JY are set so that the pixel indicating the line L1 is included in the extracted pixels.
FIG. 15B is a graph of the gradation values of the extracted pixels. The horizontal axis indicates the position of the pixel (Y coordinate). The vertical axis indicates the gradation value of the pixel. The computer 110 obtains the gravity center positions KY2 and KY3 based on the pixel data of the extracted JY pixels.
Then, the computer 110 calculates the inclination θ of the line L1 by the following equation.
θ = tan ⁻¹ {(KY2-KY3) / (KX2-KX3)}

  The computer 110 detects not only the inclination of the measurement pattern image but also the inclination of the reference pattern image. Since the method of detecting the inclination of the image of the reference pattern is substantially the same as the above method, the description thereof is omitted.

<Correction of inclination of each image (S133)>
Next, the computer 110 rotates the image based on the inclination θ detected in S132 and corrects the inclination of the image (S133). The measurement pattern image is rotationally corrected based on the inclination result of the measurement pattern image, and the reference pattern image is rotationally corrected based on the inclination result of the reference pattern image.
A bilinear method is used as an algorithm for image rotation processing. Since this algorithm is well known, its description is omitted.

<Detection of tilt during printing (S134)>
Next, the computer 110 detects an inclination (skew) during printing of the measurement pattern (S134). If the lower end of the test sheet passes the transport roller when printing the measurement pattern, the lower end of the test sheet may come into contact with the head 41 and the test sheet may move. When this happens, the correction value calculated from the measurement pattern becomes inappropriate. Therefore, it is detected whether or not the lower end of the test sheet is in contact with the head 41 by detecting the inclination at the time of printing the measurement pattern.

  FIG. 16 is an explanatory diagram of how the inclination is detected when the measurement pattern is printed. First, the computer 110 sets the left-side interval YL and the right-side interval YR in the line L1 (the uppermost line) and the line Lb1 (the lowermost line, the line formed after the lower end passes through the transport roller). Is detected. Then, the computer 110 calculates the difference between the interval YL and the interval YR. If the difference is within the predetermined range, the computer 110 proceeds to the next process (S135). If the difference is outside the predetermined range, an error is determined.

<Calculation of margin amount (S135)>
Next, the computer 110 calculates a margin amount (S135).
FIG. 17 is an explanatory diagram of the margin amount X. A solid square (outer square) in the figure indicates an image after the rotation correction in S133. A dotted-line rectangle (inner oblique rectangle) in the figure indicates an image before rotation correction. In order to make the image after rotation correction into a rectangular shape, right-angled triangular margins are added to the four corners of the rotated image when the rotation correction processing of S133 is performed.

If the inclination of the reference sheet SS and the inclination of the test sheet TS are different, the amount of added margin is different, and the position of the measurement pattern line relative to the reference pattern is relative before and after the rotation correction (S133). It will shift to. Therefore, the computer 110 obtains the margin amount X by the following equation, and subtracts the margin amount X from the line position calculated in S136, thereby preventing the shift of the line position of the measurement pattern with respect to the reference pattern.
X = (w cos θ−W ′ / 2) × tan θ

<Calculation of Line Position in Scanner Coordinate System (S136)>
Next, the computer 110 calculates the position of the line of the reference pattern and the position of the line of the measurement pattern in the scanner coordinate system (S136).

  The scanner coordinate system is a coordinate system when the size of one pixel is 1/720 × 1/720 inch. The scanner 150 has a reading position error, and considering the reading position error, the corresponding actual area of each pixel data is not exactly 1/720 inch × 1/720 inch, but in the scanner coordinate system, The size of the corresponding region (pixel) of each pixel data is 1/720 × 1/720 inch. Further, the position of the upper left pixel in each image is set as the origin of the scanner coordinate system.

  FIG. 18A is an explanatory diagram of an image range used when calculating the position of a line. Image data of an image in a range indicated by a dotted line in the figure is used when calculating the position of the line. FIG. 18B is an explanatory diagram of calculation of the position of the line. The horizontal axis indicates the position of the pixel in the y direction (scanner coordinate system). The vertical axis indicates the gradation value of the pixel (the average value of the gradation values of the pixels arranged in the x direction).

  The computer 110 obtains the position of the peak value of the gradation value and sets a predetermined range centered on this position as the calculation range. Based on the pixel data of the pixels in this calculation range, the barycentric position of the gradation value is calculated, and this barycentric position is set as the line position.

  FIG. 19 is an explanatory diagram of the calculated line positions (note that the positions shown in the figure are made dimensionless by a predetermined calculation). Although the reference pattern is composed of equally spaced lines, the positions of the calculated lines are not evenly spaced when attention is paid to the position of the center of gravity of each line of the reference pattern. This is considered to be due to the influence of the reading position error of the scanner 150.

<Calculation of absolute position of each line of measurement pattern (S137)>
Next, the computer 110 calculates the absolute position of each line of the measurement pattern (S137).
FIG. 20 is an explanatory diagram for calculating the absolute position of the i-th line of the measurement pattern. Here, the i-th line of the measurement pattern is located between the j−1th line of the reference pattern and the j-th line of the reference pattern. In the following description, the position (scanner coordinate system) of the i-th line of the measurement pattern is referred to as “S (i)”, and the position of the j-th line (scanner coordinate system) of the reference pattern is “K (j)”. " The interval between the j−1th line and the jth line of the reference pattern (interval in the y direction) is called “L”, and the j−1th line of the reference pattern and the ith line of the measurement pattern (Interval in the y direction) is referred to as “L (i)”.

First, the computer 110 calculates the ratio H of the interval L (i) to the interval L based on the following equation.
H = L (i) / L
= {S (i) -K (j-1)} / {K (j) -K (j-1)}

By the way, since the actual reference patterns on the reference sheet SS are equally spaced, if the absolute position of the first line of the reference pattern is zero, the position of an arbitrary line of the reference pattern can be calculated. For example, the absolute position of the second line of the reference pattern is 1/36 inch. Therefore, when the absolute position of the jth line of the reference pattern is “J (j)” and the absolute position of the ith line of the measurement pattern is “R (i)”, R ( i) can be calculated.
R (i) = {J (j) −J (j−1)} × H + J (j−1)

Here, a specific procedure for calculating the absolute position of the first line of the measurement pattern in FIG. 19 will be described. First, the computer 110 determines that the first line of the measurement pattern is located between the second line and the third line of the reference pattern based on the value of S (1) (373.768667). To detect. Next, the computer 110 calculates that the ratio H is 0.40143008 (= (373.7686667-309.613250) / (469.430413-309.613250)). Next, the computer 110 calculates that the absolute position R (1) of the first line of the measurement pattern is 0.98878678 mm (= 0.038928613 inch = {1/36 inch} × 0.40143008 + 1/36 inch).
In this way, the computer 110 calculates the absolute position of each line of the measurement pattern.

<Calculation of Correction Value (S138)>
Next, the computer 110 calculates correction values corresponding to a plurality of transport operations performed when the measurement pattern is formed (S138). Each correction value is calculated based on the difference between the theoretical line spacing and the actual line spacing.

  The correction value C (i) of the transport operation performed between the pass i and the pass i + 1 is from “6.35 mm” (1/4 inch, that is, the theoretical distance between the line Li and the line Li + 1) to “R. It is a value obtained by subtracting (i + 1) −R (i) ”(the absolute position of the line Li + 1 and the actual distance between the lines Li). For example, the correction value C (1) of the transport operation performed between pass 1 and pass 2 is 6.35 mm- {R (2) -R (1)}. In this way, the computer 110 calculates the correction value C (1) to the correction value C (19).

  However, when the correction value is calculated using the lines Lb1 and Lb2 below the NIP line (upstream in the transport direction), the theoretical distance between the line Lb1 and the line Lb2 is “0.847 mm” (= 3/90 Calculate as inches. In this way, the computer 110 calculates the correction value Cb in the non-NIP state.

  FIG. 21 is an explanatory diagram of a corresponding range of the correction value C (i). If the value obtained by subtracting the correction value C (1) from the initial target carry amount is set as the target in the carrying operation between pass 1 and pass 2 when the measurement pattern is printed, the actual value is obtained. The transport amount should be exactly 1/4 inch (= 6.35 mm). Similarly, if a value obtained by subtracting the correction value Cb from the original target carry amount is set as the target in the carrying operation between pass n and pass n + 1 when the measurement pattern is printed, the actual value is obtained. The carry amount should be exactly 1 inch.

<Averaging correction values (S139)>
Incidentally, since the rotary encoder 52 of the reference example does not include the origin sensor, the controller 60 can detect the rotation amount of the transport roller 23 but does not detect the rotation position of the transport roller 23. For this reason, the printer 1 cannot guarantee the rotational position of the transport roller 23 at the start of transport. That is, every time printing is performed, the rotational position of the transport roller 23 at the start of transport may be different. On the other hand, the interval between two adjacent ruled lines in the measurement pattern is affected not only by the DC component transport error when transporting at 1/4 inch, but also by the AC component transport error.

Therefore, when correcting the target carry amount, if the correction value C calculated based on the interval between two ruled lines adjacent to each other in the measurement pattern is applied as it is, the carry is caused by the influence of the AC component carry error. The amount may not be corrected correctly. For example, even when a transport operation of a 1/4 inch transport amount is performed between pass 1 and pass 2 as in the case of printing a measurement pattern, the rotation position of the transport roller 23 at the start of transport is If the measurement pattern is different from the printing time, even if the target carry amount is corrected with the correction value C (1), the carry amount is not correctly corrected. If the rotation position of the conveyance roller 23 at the start of conveyance is 180 degrees different from that at the time of printing the measurement pattern, the conveyance amount is not corrected correctly because of the influence of the AC component conveyance error. Can get worse.
Therefore, here, in order to correct only the DC component transport error, the correction amount Ca for correcting the DC component transport error is obtained by averaging four correction values C as shown in the following equation. Is calculated.
Ca (i) = {C (i-1) + C (i) + C (i + 1) + C (i + 2)} / 4

Here, the reason why the correction value Ca for correcting the DC component transport error can be calculated by the above equation will be described.
As described above, the correction value C (i) of the transport operation performed between the pass i and the pass i + 1 is “6.35 mm” (1/4 inch, that is, the theoretical distance between the line Li and the line Li + 1. ) Minus “R (i + 1) −R (i)” (the absolute position of the line Li + 1 and the actual distance between the lines Li). Then, the above equation for calculating the correction value Ca has the following meaning.
Ca (i) = [25.4 mm- {R (i + 3) -R (i-1)}] / 4

  That is, the correction value Ca (i) is a difference between the distance between two lines (line Li + 3 and line Li-1) that should theoretically be 1 inch apart and 1 inch (the conveyance amount for one rotation of the conveyance roller 23). The value divided by. In other words, the correction value Ca (i) is a value corresponding to the interval between the line Li-1 and the line Li + 3 formed after the line is formed and conveyed for 1 inch.

  Therefore, the correction value Ca (i) calculated by averaging the four correction values C is not affected by the AC component transport error and is a value reflecting the DC component transport error.

  The correction value Ca (2) of the transport operation performed between pass 2 and pass 3 is a value obtained by dividing the sum of correction values C (1) to C (4) by 4 (correction value C (1)). (Average value of .about.C (4)). In other words, the correction value Ca (2) is a value corresponding to the interval between the line L1 formed in the pass 1 and the line L5 formed in the pass 5 after the line L1 is formed and conveyed for 1 inch. Become.

  Further, when i-1 is equal to or less than zero when calculating the correction value Ca (i), C (1) is applied as the correction value C (i-1). For example, the correction value Ca (1) of the transport operation performed between pass 1 and pass 2 is calculated as {C (1) + C (1) + C (2) + C (3)} / 4. Further, when i + 1 is 20 or more when calculating the correction value Ca (i), C (19) is applied to C (i + 1) for calculating the correction value Ca. Similarly, when i + 2 is 20 or more, C (i + 2) applies C (19). For example, the correction amount Ca (19) of the conveyance operation performed between the pass 19 and the pass 20 is calculated as {C (18) + C (19) + C (19) + C (19)} / 4.

  In this way, the computer 110 calculates the correction values Ca (1) to Ca (19). Thus, a correction value for correcting the DC component transport error is obtained for each 1/4 inch range.

<Storage of correction value (S104)>
Next, the computer 110 stores the correction value in the memory 63 of the printer 1 (S104).
FIG. 22 is an explanatory diagram of a table stored in the memory 63. The correction values stored in the memory 63 are the correction values Ca (1) to Ca (19) in the NIP state and the correction value Cb in the non-NIP state. Further, boundary position information for indicating a range to which each correction value is applied is also stored in the memory 63 in association with each correction value.

  The boundary position information associated with the correction value Ca (i) is information indicating the position (theoretical position) corresponding to the line Li + 1 of the measurement pattern, and the correction value Ca (i) is applied to this boundary position information. The boundary of the lower end side of the range to be shown is shown. Note that the upper end side boundary can be obtained from the boundary position information associated with the correction value Ca (i−1). Therefore, for example, the application range of the correction value C (2) is a range between the position of the line L1 and the position of the line L2 (where the nozzle # 90 is located) with respect to the paper S. Note that since the range in which the non-NIP state is set is known, the boundary value information may not be associated with the correction value Cb.

  In the printer manufacturing factory, a table reflecting individual characteristics of each printer is stored in the memory 63 for each printer manufactured. The printer storing this table is packed and shipped.

<Conveying operation using correction value Ca>
When the correction value Ca is stored in the memory, when printing is performed, the controller 60 reads the table from the memory 63, corrects the target transport amount based on the correction value, and transports based on the corrected target transport amount. Perform the action.

  FIG. 23A is an explanatory diagram of correction values in the first case. In the first case, the position of the nozzle # 90 before the transport operation (relative position with respect to the paper) matches the boundary position on the upper end side of the application range of the correction value Ca (i), and the position of the nozzle # 90 after the transport operation Corresponds to the boundary position on the lower end side of the application range of the correction value Ca (i). In such a case, the controller 60 sets the correction value Ca (i), drives the carry motor 22 with the target value obtained by adding the correction value Ca (i) from the initial target carry amount F, and carries the paper. To do.

  FIG. 23B is an explanatory diagram of correction values in the second case. In the second case, the position of the nozzle # 90 before and after the transport operation is both within the application range of the correction value Ca (i). In such a case, the controller 60 sets a value obtained by multiplying the ratio F / L between the initial target transport amount F and the transport range length L of the applicable range by Ca (i) as a correction value. Then, the controller 60 drives the carry motor 22 with the target value obtained by adding the correction value Ca (i) × (F / L) from the initial target carry amount F to carry the paper.

  FIG. 23C is an explanatory diagram of correction values in the third case. In the third case, the position of the nozzle # 90 before the transport operation is within the application range of the correction value Ca (i), and the position of the nozzle # 90 after the transport operation is within the application range of the correction value Ca (i + 1). is there. Here, of the target transport amount F, the transport amount within the application range of the correction value Ca (i) is F1, and the transport amount within the application range of the correction value Ca (i + 1) is F2. In such a case, the controller 60 sets the sum of a value obtained by multiplying Ca (i) by F1 / L and a value obtained by multiplying Ca (i + 1) by F2 / L as a correction value. Then, the controller 60 drives the carry motor 22 with the target value obtained by adding the correction value from the initial target carry amount F to carry the paper.

  FIG. 23D is an explanatory diagram of correction values in the fourth case. In the fourth case, the paper is conveyed so as to pass through the application range of the correction value Ca (i + 1). In such a case, the controller 60 sets the sum of a value obtained by multiplying Ca (i) by F1 / L, a value obtained by multiplying Ca (i + 1) and Ca (i + 2) by F2 / L as a correction value. Then, the controller 60 drives the carry motor 22 with the target value obtained by adding the correction value from the initial target carry amount F to carry the paper.

  Thus, when the controller corrects the initial target transport amount F and controls the transport unit based on the corrected target transport amount, the actual transport amount is corrected to become the initial target transport amount F, The DC component transport error is corrected.

<Evaluation process for transport amount correction>
Even if the DC component transport error is corrected using the correction value obtained as described above, it is evaluated how accurately the correction of the transport amount is performed. There is a need. Here, after the correction value determination process is completed, the conveyance amount correction evaluation process is performed.

  FIG. 24 is a flowchart of the conveyance amount correction evaluation process. This conveyance amount correction evaluation process is also performed in the inspection process of the printer manufacturing factory. Hereinafter, each process will be described with reference to this flowchart.

  FIG. 25 is a diagram illustrating a confirmation pattern used in the evaluation process for the conveyance amount correction. First, the conveyance amount is corrected while using the obtained correction value, and a confirmation pattern as shown in the figure is printed on the test sheet TS '(S241). Here, 4 × 6 size paper is used. The confirmation pattern is composed of lines L1 'to L20'. Further, in the conveyance of the sheet during the printing of the confirmation pattern, the conveyance amount is corrected and conveyed by the method described in the “conveying operation using the correction value Ca”.

  The confirmation patterns from the line L1 'to the line L20' are formed by substantially the same method as that for forming the measurement patterns L1 to L20 in FIG. The difference from the measurement pattern is that the confirmation pattern is formed while the carry amount is corrected, the lines Lb1 and Lb2 from the lower end of the NIP line are not formed, and the line L20. 'Is extended to the same length as the line L1'.

  First, after the test sheet TS 'is conveyed to a predetermined printing start position, in pass 1, ink droplets are ejected from the nozzle # 90 to form a line L1'. After pass 1, the controller 60 rotates the transport roller 23 by 1/4 to transport the test sheet TS 'by about 1/4 inch. After the conveyance, in pass 2, ink droplets are ejected from the nozzle # 90, and a line L2 'is formed. Thereafter, the same operation is repeated, and the lines L1 'to L20' are formed at intervals of about 1/4 inch. Since lines are formed in this way, the distance from the line L1 'to the line L5' should be 1 inch when accurate conveyance is performed. Similarly, the distance from line L2 'to line L6' should be 1 inch.

  By forming the lines in this way, there is a line that is formed 1 inch apart for each of the lines L1 'to L16'. Then, based on the distance corresponding to one round of the transport roller 23, the effect of the correction on the DC component transport error can be evaluated.

  Next, the confirmation pattern and the reference pattern are read (S241). The reading of the confirmation pattern and the reference pattern here is performed by the same process as the “reading of the measurement pattern and the reference pattern” in S102 of FIG.

  Next, an absolute position calculation process is performed for each line L1 'to L20' of the confirmation pattern (S243). The absolute position calculation method here is the same as the processing of S131 to S137 of the correction value calculation processing in FIG.

  FIG. 26 is a flowchart of an absolute position calculation process. First, image division processing is performed in the calculation processing of the absolute position of each line of the confirmation pattern (S261). This is a process similar to the process of S131 described above, whereby the confirmation pattern and the reference pattern are divided, and inclination correction described later can be performed separately.

  Next, the inclinations of the confirmation pattern and the reference pattern are detected (S262). As a method for detecting the inclination, the same method as “detecting the inclination of each image” in S132 is used. Then, the image is rotated based on the detected inclination, and the inclination of the image is corrected (S263). As the image rotation processing algorithm used here, the bilinear method is used as in “correction of the inclination of each image” in S133.

  FIG. 27 is an explanatory diagram of how the inclination is detected when the confirmation pattern is printed. In step S264, an inclination (skew) during printing of the confirmation pattern is detected. This process is substantially the same as the “detection of inclination during printing” in S134. The difference is that a left interval YL 'and a right interval YR' in the lines L1 'and L20' are detected.

  Next, a margin amount is calculated (S265). This process is the same as the process of “calculation of margin amount” in S135. By this processing, the shift of the line position of the confirmation pattern with respect to the reference pattern is prevented.

  Next, the line position of the reference pattern and the line position of the confirmation pattern in the scanner coordinate system are calculated (S266). This process is the same as the “calculation of the absolute position of each line in the scanner coordinate system” in S136.

  Next, the absolute position of each line of the confirmation pattern is calculated by the computer 110 (S267). This process is substantially the same as the process of “calculation of absolute position of each line of measurement pattern” in S137. Here, the “measurement pattern” in S137 is replaced with the “confirmation pattern”.

  Thus, when the absolute position of the line of the confirmation pattern is calculated, the absolute position value is associated with each line number and stored in the memory of the computer 110.

  When the calculation processing of the absolute position of each line of the confirmation pattern is completed, the correction result is evaluated next (S244). In the evaluation of the correction result, the distance between the lines separated by 1 inch is obtained, and it is evaluated whether the distance is different from 1 inch which is the length of one circumference of the roller.

FIG. 28 is a diagram for explaining the distance Di between the lines. In the figure, distances D1 to D16 from line L5 ′ to line L20 ′ that are 1 inch apart from the line L1 ′ to line L16 ′ are described. For example, when the first pattern of the confirmation pattern is the line L1 ′, the corresponding second pattern is the line L5 ′, and when the first pattern is the line L2 ′, the corresponding second pattern is the line L6 ′. The distance from the line L1 ′ to the line L5 ′ that is 1 inch away is D1, and the distance between the line L6 that is 1 inch away from the line L2 is D2. That is, the distance Di from the absolute position R ′ (i) of the line is obtained as follows.
Di = R ′ (i + 4) −R ′ (i)

These distances D1 to D16 are distances between lines recorded while the conveyance amount is corrected so as to be 1 inch, which is the distance of one rotation of the conveyance roller. Therefore, when the DC component is corrected with high accuracy, all of these Di values should be exactly 1 inch. Therefore, the effect of correcting the DC component transport error can be evaluated by how much each of these D1 to D16 is different from 1 inch. For example, for each distance Di, the effect of correction on the DC component transport error can be evaluated by the following equation. Here, D0 is 1 inch, and TH is a predetermined threshold value.
| Di-D0 | <TH

  If the above equation is satisfied, the printer can be shipped after evaluating that the correction effect on the DC component has been confirmed. On the other hand, if the above equation is not satisfied, it can be evaluated that the effect of correction on the DC component cannot be confirmed, and the printer can be prevented from being shipped.

As another evaluation method, the correction effect can be evaluated using the following equation. If D0 is 1 inch and the evaluation value is E,

And The above equation finds the sum of absolute values of differences with respect to 1 inch of each distance Di. The evaluation value E becomes smaller as the distances Di are closer to 1 inch. In other words, in the above equation, the smaller the evaluation value E, the more accurate the conveyance is performed.

  Therefore, when the evaluation value E is smaller than the predetermined threshold value TH ′, it is evaluated that the printer can be shipped. When the evaluation value E is equal to or higher than the predetermined threshold value TH, The printer may not be shipped.

  There are various other methods for evaluating the distance Di, and other methods may be adopted.

  By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

=== Second Embodiment ===
In the second embodiment, the processing until obtaining a correction value for correcting the DC component transport error is the same as that in the first embodiment. Here, a method for confirming the effect of the conveyance amount correction by forming the confirmation pattern on the sheet while performing the conveyance amount correction using the obtained correction value will be described.

  FIG. 29 is a flowchart of the conveyance amount correction evaluation process in the second embodiment. First, in the carry amount correction evaluation process, a confirmation pattern is printed while carrying amount is corrected (S291).

<Printing Confirmation Pattern (S291)>
FIG. 30 is a diagram showing a confirmation pattern in the second embodiment. In FIG. 30, twelve confirmation patterns including patterns A and B are printed. Here, first, a method of forming individual patterns A and B will be described, and then a method of forming a confirmation pattern on the entire sheet (test sheet TS ″) will be described.

  FIG. 31 is a diagram for explaining the relationship between the pattern A and the nozzles of the head. Each pattern is formed by one pass. Here, only black K nozzles are used, and ink droplets are ejected only in the forward direction of the head 41. Pattern A is formed by ink droplets ejected from nozzle # 69 to nozzle # 90 in one pass.

  FIG. 32 is a diagram for explaining the relationship between the pattern B and the nozzles of the head. Pattern B is formed by ink droplets ejected from nozzle # 1 to nozzle # 22 in one pass.

  The pattern A and the pattern B formed in this way are 22/90 inches in the paper transport direction and have a rectangular shape of 50/90 inches in a direction perpendicular to the paper transport direction. Then, the pattern A is formed so as to be shifted from the pattern B by 20/90 inches on the left side of the sheet. The pattern B is formed so as to be shifted from the pattern A by 22/90 inches in the transport direction.

  FIG. 33 is a relative movement diagram of the head when a confirmation pattern is formed on 4 × 6 paper. With reference to the drawings, each pass and the conveyance performed before and after the confirmation pattern will be described. The numbers written in the head 41 in the figure are pass numbers. Further, the numbers described in each pattern on the test sheet TS ″ in the drawing are also the pass numbers when the pattern is formed. For example, “1” is described because the pattern formed near the uppermost end of the test sheet TS ″ is formed in the first pass. Further, since the pattern formed near the lowermost end of the test sheet TS ″ is formed in the 16th pass, “16” is described. In addition, P1 to P12 described in the figure indicate the numbers of the confirmation patterns. For example, P1 indicates the confirmation pattern P1.

  First, the test sheet TS ″ is transported so that the nozzle # 90 can eject ink droplets to a position advanced 38.6 mm from the upper end of the sheet. Then, the first pass (corresponding to the pass in FIG. 31 described above) is performed, and the pattern A of the confirmation pattern P1 is formed.

  Next, the test sheet TS ″ is transported by 1/4 inch in the transport direction. Then, the pattern A of the confirmation pattern P2 is formed in the second pass. In this way, the 1/4 inch conveyance and the pass are repeated in the same manner, and the pattern A of the confirmation pattern P4 is formed. Then, 1/4 inch conveyance is performed in the conveyance direction.

  In the next fifth pass, the pattern B of the confirmation pattern P1 and the pattern A of the confirmation pattern P5 are formed simultaneously. At this time, in the fifth pass, the above-described pass in FIG. 31 and the pass in FIG. 32 are performed simultaneously. As described above, the pattern B of the confirmation pattern P1 is formed by the nozzles # 1 to # 22, and the pattern A of the confirmation pattern P5 is formed by the nozzles # 69 to # 90.

  FIG. 34 is a diagram for explaining a method of forming the pattern B of the confirmation pattern P1 and the pattern A of the confirmation pattern P5. The figure shows that the pattern B of the confirmation pattern P1 and the pattern A of the confirmation pattern P5 are formed simultaneously. It is also shown that the distance from the upper end of the pattern B of the confirmation pattern P1 formed simultaneously to the lower end of the pattern A of the confirmation pattern P5 is 1 inch.

  The pattern A of the confirmation pattern P1 was formed in the first pass, and 1 inch was conveyed from the position where the first pass was performed before the fifth pass was performed. Then, after one inch of conveyance, the pattern B of the confirmation pattern P1 is formed. Then, when the pattern B of the confirmation pattern P1 is formed by accurately carrying 1 inch, the lower end of the pattern A of the confirmation pattern P1 and the upper end of the pattern B are formed so as to be aligned in the carrying direction. Become. As will be described later, the correction result is evaluated based on the overlapping state of the pattern A and the pattern B.

  When the fifth pass is completed in this way, next 1/4 inch conveyance is performed. Then, in the sixth pass, the pattern B of the confirmation pattern P2 and the pattern A of the confirmation pattern P6 are formed. Thereafter, the 1/4 inch conveyance and the formation of the pattern A and the pattern B are repeatedly performed, and the processes up to the 12th pass are performed. Then, up to the pattern A of the confirmation pattern P12 is formed. Thereafter, 1/4 inch conveyance is performed.

  Next, the confirmation pattern P13 to the confirmation pattern P16 are performed from the 13th pass to the 16th pass, and each pattern B is formed.

<Evaluation of correction result (S292)>
In this way, when the printing of the confirmation pattern is completed, the correction result is evaluated based on the confirmation pattern (S292).

  FIG. 35A to FIG. 35C are diagrams for explaining the appropriateness of the carry amount determined by the overlapping state of the pattern A and the pattern B. FIG. When the pattern A and the pattern B are viewed as a set of patterns, the pattern A is formed first as the order of formation, and then the conveyance for several passes is performed, and the pattern B is formed. Therefore, by observing the interval between the pattern A and the pattern B, that is, the overlapping state of the rectangular pattern A and the pattern B, the conveyance amount between the formation of the pattern A and the formation of the pattern B is appropriate. It can be determined whether the amount.

  For example, in the above description, the confirmation pattern P1 is formed in the first pass, and 1 inch is conveyed from the position where the first pass is performed before the fifth pass is performed. Then, after the conveyance of 1 inch, the pattern B of the confirmation pattern P1 was formed. Then, when the pattern B of the confirmation pattern P1 is formed by accurately carrying 1 inch, the lower end of the pattern A of the confirmation pattern P1 and the upper end of the pattern B are formed so as to be aligned in the carrying direction. Become.

  In FIG. 35A, white stripes and black stripes are not generated between the pattern A and the pattern B. This is because the pattern A and the pattern B are formed so as to be accurately aligned because the conveyance amount between the formation of the pattern A and the formation of the pattern B is exactly 1 inch. In this case, it can be determined that an appropriate amount of conveyance has been performed.

  In FIG. 35B, white stripes are generated between the pattern A and the pattern B. This is because the conveyance amount from the formation of the pattern A to the formation of the pattern B is larger than 1 inch, and the pattern A and the pattern B are formed apart from each other. At this time, it can be determined that the actual carry amount is larger than the proper carry amount.

  In FIG. 35C, black streaks are generated between the pattern A and the pattern B. This is because the transport amount from the time when the pattern A is formed to the time when the pattern B is formed is smaller than 1 inch, and the patterns are partially overlapped. At this time, it can be determined that the actual transport amount is smaller than the proper transport amount.

  Thus, when the confirmation pattern P1 to the confirmation pattern P12 are formed, it becomes possible to confirm the overlapping state of the patterns A and B of each confirmation pattern. When the pattern A and the pattern B are appropriately formed side by side, it can be evaluated that the printer can be shipped as a product on the assumption that the effect of the conveyance amount correction has been confirmed. On the other hand, if the pattern A and the pattern B often overlap, or if the pattern A and the pattern B are often separated, the effect of the carry amount correction cannot be confirmed, and the printer cannot be shipped as a product. Can be evaluated.

  In the above description, the overlapping state of the pattern A and the pattern B is visually confirmed. However, the test sheet TS '' is read by a scanner, and the area where the pattern A and the pattern B overlap is calculated. It is also possible to calculate the distance at which the pattern A and the pattern B are separated. When the area where the pattern A and the pattern B overlap is larger than a predetermined threshold value, or when the distance between the pattern A and the pattern B is larger than the predetermined threshold value, the conveyance is performed. If the effect of the amount correction cannot be confirmed, it can be evaluated that the printer cannot be shipped as a product.

=== Other Embodiments ===
The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About the head>
In the above-described embodiment, ink is ejected using a piezoelectric element. However, the method for discharging the liquid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

  In the above-described embodiment, the head is provided on the carriage. However, the head may be provided in an ink cartridge that is detachable from the carriage.

=== Summary ===
(1) In the evaluation process of the conveyance amount correction in the present embodiment, first, according to the target conveyance amount as a target, the conveyance roller 23 is rotated and the sheet is conveyed to the head 41 in the conveyance direction, and this sheet The measurement pattern (lines L1 to L20, Lb1, Lb2) for confirming the transport amount is recorded on the head 41.

  Next, based on these measurement patterns (lines L1 to L20, Lb1, Lb2), there are correction values for correcting the target transport amount when transporting the paper, and the relative position between the head 41 and the paper. A correction value associated with is obtained.

Next, the first pattern (line L1) is recorded on the head 41, and the sheet is conveyed from the recording position of the first pattern (line L1) while correcting the target conveyance amount using the correction value corresponding to the relative position. 23, the second pattern (line L5) is recorded on the head 41. Then, based on the distance between the first pattern and the second pattern, the result of correcting the target carry amount using the correction value is evaluated.
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

(2) Further, recording the second pattern on the head 41 may include recording a plurality of sets of the first pattern and the second pattern on the sheet. For example, the line L1 to the line L16 can be recorded as the first pattern, and the line L5 to the line L20 can be recorded as the second pattern corresponding to each of them.
By doing so, it is possible to evaluate a DC component correction result in a region in which a sheet is subdivided in the conveyance direction using a set of a plurality of first patterns and second patterns.

(3) The recording of the second pattern by the head 41 may be performed by recording another pattern of the first pattern between the first pattern and the second pattern. For example, lines L2, L3, and L4 can be recorded as another set of first patterns between the line L1 as the first pattern and the line L5 as the second pattern.
In this way, it is possible to evaluate the DC component correction result in a region where the paper is subdivided in the transport direction using a set of a plurality of first patterns and second patterns.

(4) Further, recording the second pattern on the head 41 described above means that another set of the first pattern is provided at the division position when the interval between the first pattern and the second pattern is equally divided into a plurality of portions. It may be recorded. For example, the line L1 and the line L5 are separated by 1 inch. Assuming that this interval is divided into four, another set of first patterns can be recorded by arranging the line L2, the line L3, and the line L4 at each division position.
In this way, it is possible to evaluate the DC component correction result in a region where the paper is subdivided in the transport direction using a set of a plurality of first patterns and second patterns.

(5) Also, evaluating the result of correcting the target carry amount is that the target carry amount is properly corrected when the absolute value of the distance between the first pattern and the second pattern is smaller than a predetermined threshold value. It is good also as evaluating that it was performed.
By doing so, it is possible to evaluate whether or not the conveyance has been performed with accuracy by correcting the target conveyance amount, and when the conveyance is not performed with accuracy, it is possible to take measures such as not shipping the product. .

(6) Also, evaluating the result of correcting the target carry amount is that the target carry amount is corrected when the sum of absolute values of the distances between the first pattern and the second pattern is smaller than a predetermined threshold value. It is good also as evaluating that it was performed appropriately.
By doing so, it is possible to evaluate whether or not the conveyance has been performed with accuracy by correcting the target conveyance amount, and when the conveyance is not performed with accuracy, it is possible to take measures such as not shipping the product. .

(7) Further, as shown in the second embodiment described above, the first pattern and the second pattern may be rectangular patterns.
By doing in this way, the effect of conveyance amount correction | amendment can be confirmed easily based on the overlap condition of a 1st pattern and a 2nd pattern.

(8) In addition, evaluating the result of correcting the target carry amount may include evaluating the result of correcting the target carry amount based on the degree of overlap between the first pattern and the second pattern.
By doing in this way, the effect of conveyance amount correction | amendment can be confirmed easily visually.

(9) The computer 110 constituting the transport amount correction evaluation apparatus uses a correction value for correcting the target transport amount when transporting the paper based on the measurement pattern for confirming the transport amount of the paper. Therefore, a correction value associated with the relative position between the paper and the head on which the confirmation pattern is recorded is obtained.

Next, the computer 110 is transported by the transport amount corresponding to one rotation of the roller that transports the sheet from the recording position of the first pattern while correcting the target transport amount using the first pattern and the correction value. The result of the correction using the correction value is evaluated based on the distance from the second pattern recorded after that.
By doing so, it is possible to evaluate the correction result when the medium is transported by correcting the target transport amount using the correction value for correcting the DC component transport error.

(10) Needless to say, there is a program for performing the above-described transport amount correction evaluation process.

1 is a block diagram of an overall configuration of a printer 1. FIG. FIG. 2A is a schematic diagram of the overall configuration of the printer 1. FIG. 2B is a cross-sectional view of the overall configuration of the printer 1. It is explanatory drawing which shows the arrangement | sequence of a nozzle. 4 is an explanatory diagram of a configuration of a transport unit 20. FIG. 6 is a graph for explaining AC component transport error. It is a graph (conceptual figure) of the conveyance error which arises when conveying paper. It is a flowchart until it determines the correction value for correct | amending conveyance amount. FIG. 8A to FIG. 8C are explanatory diagrams of how the correction value is determined. It is explanatory drawing of the mode of printing of the pattern for a measurement. FIG. 10A is a longitudinal sectional view of the scanner 150. FIG. 10B is a top view of the scanner 150 with the upper lid 151 removed. It is a graph of the error of the reading position of a scanner. FIG. 12A is an explanatory diagram of the reference sheet SS. FIG. 12B is an explanatory diagram showing a state in which the test sheet TS and the reference sheet SS are set on the platen glass 152. It is a flowchart of the correction value calculation process in S103. It is explanatory drawing of a division | segmentation (S131) of an image. FIG. 15A is an explanatory diagram illustrating a state where the inclination of the image of the measurement pattern is detected. FIG. 15B is a graph of the gradation values of the extracted pixels. It is explanatory drawing of the mode of the detection of the inclination at the time of printing of the pattern for a measurement. It is explanatory drawing of the margin amount X. FIG. FIG. 18A is an explanatory diagram of an image range used when calculating the position of a line. FIG. 18B is an explanatory diagram of calculation of the position of the line. It is explanatory drawing of the position of the calculated line. It is explanatory drawing of calculation of the absolute position of the i-th line of the pattern for a measurement. It is explanatory drawing of the range to which correction value C (i) respond | corresponds. It is explanatory drawing of the table memorize | stored in the memory. It is explanatory drawing of the correction value in a 1st case. It is explanatory drawing of the correction value in a 2nd case. It is explanatory drawing of the correction value in a 3rd case. It is explanatory drawing of the correction value in a 4th case. It is a flowchart of the evaluation process of conveyance amount correction. It is a figure which shows the pattern for confirmation used in the evaluation process of conveyance amount correction | amendment. It is a flowchart of an absolute position calculation process. It is explanatory drawing of the mode of the detection of the inclination at the time of printing of the pattern for confirmation. It is a figure for demonstrating the distance Di between lines. It is a flowchart of the evaluation process of conveyance amount correction in the second embodiment. It is a figure which shows the pattern for confirmation in 2nd Embodiment. It is a figure for demonstrating the relationship between the pattern A and the nozzle of a head. It is a figure for demonstrating the relationship between the pattern B and the nozzle of a head. FIG. 4 is a relative movement diagram of a head when a confirmation pattern is formed on 4 × 6 paper. It is a figure for demonstrating the formation method of the pattern B of the pattern P1 for confirmation, and the pattern A of the pattern P5 for confirmation. FIG. 35A to FIG. 35C are diagrams for explaining the appropriateness of the carry amount determined by the overlapping state of the pattern A and the pattern B. FIG.

Explanation of symbols

1 printer, 110 computer,
20 transport unit, 21 paper feed roller, 22 transport motor, 23 transport roller,
24 platen, 25 paper discharge roller, 26 driven roller, 27 driven roller,
30 Carriage unit, 31 Carriage, 32 Carriage motor,
40 head units, 41 heads,
50 detector groups, 51 linear encoders,
52 Rotary encoder, 521 scale, 522 detector,
53 Paper detection sensor, 54 Optical sensor,
60 controller, 61 interface unit, 62 CPU, 63 memory,
64 unit control circuit,
150 scanner, 151 top cover, 152 platen glass,
153 reading carriage, 154 guide section, 155 moving mechanism,
157 exposure lamp, 158 line sensor, 159 optical system,
TS test sheet, SS reference sheet

Claims (10)

A measurement pattern for recording on the head a measurement pattern for confirming the conveyance amount of the medium while rotating the roller according to the target conveyance amount as a target and conveying the medium in the conveyance direction with respect to the head. Recording step;
A correction value for correcting the target transport amount when transporting the medium based on the measurement pattern, and a correction value for determining a correction value associated with a relative position between the head and the medium A decision step;
The first pattern is recorded on the head, and the medium is equivalent to one rotation of the roller from the recording position of the first pattern while correcting the target transport amount using the correction value corresponding to the relative position. A second pattern recording step in which the head is transported by a transport amount, and the head records a second pattern;
An evaluation step of evaluating a result of the correction of the target transport amount using the correction value based on the distance between the first pattern and the second pattern;
Conveyance correction evaluation method including   The transport amount correction evaluation method according to claim 1, wherein the second pattern recording step includes a step of recording a plurality of sets of the first pattern and the second pattern on the medium.   The transport amount correction evaluation method according to claim 2, wherein the second pattern recording step includes a step of recording another set of first patterns between the set of the first pattern and the second pattern.   The second pattern recording step includes a step of recording the other pattern of the first pattern at a division position when an interval between the first pattern and the second pattern is equally divided into a plurality. 3. The conveyance amount correction evaluation method according to 3.   The evaluation step includes a step of evaluating that the correction of the target transport amount is appropriately performed when the absolute value of the distance between the first pattern and the second pattern is smaller than a predetermined threshold value. The conveyance amount correction | amendment evaluation method in any one of Claims 1-4.   The evaluation step includes a step of evaluating that the correction of the target transport amount is properly performed when the sum of absolute values of the distance between the first pattern and the second pattern is smaller than a predetermined threshold value. The conveyance amount correction | amendment evaluation method in any one of Claims 2-4 containing.   The conveyance amount correction evaluation method according to claim 3, wherein the first pattern and the second pattern are rectangular patterns.   The transport amount correction evaluation method according to claim 7, wherein the evaluation step includes a step of evaluating a correction result of the target transport amount based on a degree of overlap between the first pattern and the second pattern. A correction value for correcting a target transport amount when transporting the medium, based on a measurement pattern for confirming the transport amount of the medium, and between the medium and the head on which the confirmation pattern is recorded. Find the correction value associated with the relative position,
Recording is performed after the first pattern and the correction value are used to correct the target conveyance amount, and then conveyed from the recording position of the first pattern by a conveyance amount corresponding to one rotation of the roller that conveys the medium. A transport amount correction evaluation apparatus that evaluates a correction result using the correction value based on a distance from the second pattern. A program for operating the conveyance amount correction evaluation apparatus,
Rotating the roller according to a target transport amount to be a target and transporting the medium in the transport direction with respect to the head, and recording a measurement pattern for confirming the transport amount of the medium on the head;
Obtaining a correction value for correcting the target transport amount when transporting the medium based on the measurement pattern, the correction value being associated with the relative position between the head and the medium; ,
The head is recorded with the first pattern, and the medium is equivalent to one rotation of the roller from the recording position of the first pattern while correcting the target transport amount using the correction value corresponding to the relative position. Transporting with a transport amount to be recorded, and causing the head to record a second pattern;
Evaluating a correction result of the target transport amount using the correction value based on a distance between the first pattern and the second pattern;
A program for causing the transport amount correction evaluation apparatus to perform