JP4720103B2 - Printing apparatus and test pattern manufacturing method - Google Patents

Description

  The present invention relates to a printing apparatus, a test pattern, and a test pattern manufacturing method.

  2. Related Art Inkjet printers that perform printing by ejecting ink are known as printing apparatuses that print images on various media such as paper, cloth, and film. In such an ink jet printer, printing is performed by alternately repeating the process of ejecting ink from the nozzles and the process of moving the medium in the transport direction.

FIG. 30A is an explanatory diagram of printing by such an ink jet printer. A head 41 having a plurality of nozzles moves in the scanning direction, ink is ejected from the nozzles, and a strip-shaped print image piece BP1 having the width of the head is formed on the paper. Next, the transport unit transports the paper in the transport direction by a transport amount corresponding to the width of the head 41. Thereafter, the printer repeats the same ejection operation and conveyance operation, and forms print images by connecting the print image pieces BP2, BP3,... On the paper in the conveyance direction.
Since the transport unit that performs the transport operation transports paper using components such as a motor and gears, an error may occur in the transport amount.

  FIG. 30B is an explanatory diagram of printing when there is a conveyance error. Due to a transport error, if the transport unit transports the paper with a transport amount larger than the target transport amount (target transport amount), the distance between the print image strips is the same as the boundary between the print image strip BP1 and the print image strip BP2. A gap is formed in the pattern, and a light striped pattern (also called “bright banding”, “white banding”, or “light banding”) is generated. Further, due to a transport error, when the transport unit transports the paper with a transport amount smaller than the target transport amount, an overlap occurs between the print image pieces as in the boundary between the print image piece BP2 and the print image piece BP3. Dark stripes (also called “dark banding”, “black banding”, and “dark banding”) occur. Such banding causes deterioration in image quality.

Therefore, in order to suppress the influence of such a transport error, the target transport amount is corrected during the transport operation (see, for example, Patent Document 1).
JP 2001-71475 A

  In order to determine the correction amount for the target carry amount, a test pattern (test pattern) is printed as means for detecting the carry error amount. A plurality of correction patterns in which the correction amount with respect to the target carry amount is changed in stages are printed on the test pattern. Then, by selecting an optimum pattern from among a plurality of correction patterns, a conveyance error is detected, and a correction amount is determined so that appropriate correction can be performed.

  Each correction pattern formed in the test pattern corresponds to a specific correction amount. Therefore, it is desirable that as many correction patterns as possible be formed in a narrow area on the paper.

  Accordingly, an object of the present invention is to form more correction patterns in a narrow area on a medium.

A main invention for achieving the above object includes a plurality of nozzles that eject ink while moving in a moving direction, and a transport unit that transports a medium in a transport direction, and the plurality of the plurality of nozzles before transport by the transport unit. A correction pattern having a pre-transport pattern formed by nozzles and a post-transport pattern formed by the plurality of nozzles after transport by the transport unit and formed adjacent to the transport direction. A printing apparatus that prints a plurality of prints on a medium, wherein (A) a plurality of the pre-transport patterns in the plurality of correction patterns eject ink while the plurality of nozzles move once in the movement direction. Formed and ejecting ink while the plurality of nozzles move in the moving direction; and the transport unit transports the medium. It and is repeated a plurality of times alternately, while one of the transport after the pattern is formed between the movement of the nozzle of one, a plurality of the transport after the pattern of the plurality of correction patterns are formed The plurality of correction patterns are arranged in a direction intersecting the transport direction and formed on the medium, and (B) the medium is transported in the transport direction with a transport amount shorter than the nozzle pitch of the plurality of nozzles. Each time the medium is transported and the medium is transported in the transport direction with the short transport amount, the nozzle used for forming the post-transport pattern is changed, whereby the pre-transport pattern and the post-transport The printing apparatus is characterized in that the plurality of correction patterns that are stepwise different from each other at intervals shorter than the carry amount are formed.

  Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

=== Summary of disclosure ===
At least the following matters will become clear from the description of the present specification and the accompanying drawings.

A transport unit for transporting the medium in the transport direction;
A correction pattern having a pre-transport pattern formed before transport by the transport unit, and a post-transport pattern formed after transport by the transport unit and formed adjacent to the pre-transport pattern and the transport direction. A printing device for printing a plurality of images on a medium,
A printing apparatus, wherein a plurality of the correction patterns are arranged on the medium in a direction intersecting the transport direction.
According to such a printing apparatus, more correction patterns can be formed in a narrow area on the medium.

  In this printing apparatus, one of the pre-transport pattern and the post-transport pattern of the plurality of correction patterns is formed at the same position in the transport direction, and the other pattern is the transport pattern. It is desirable to form at different positions with respect to the direction. According to such a printing apparatus, more correction patterns can be formed in a narrow area on the medium.

  In this printing apparatus, after the other pattern of a correction pattern is formed on the medium, the medium is transported by the transport unit, and the other pattern of other correction patterns is formed on the medium. It is desirable. According to such a printing apparatus, the amount of conveyance performed between the formation of the pre-conveyance pattern for a certain correction pattern and the formation of the post-conveyance pattern, and the formation of the pattern for other correction patterns before conveyance to the post-conveyance pattern Therefore, the amount of conveyance performed before the formation of is different. As a result, the interval between the pre-carrying pattern and the post-carrying pattern is different for each correction pattern.

  In this printing apparatus, it is preferable to further include a carriage that moves a plurality of nozzles arranged in the transport direction. Then, one of the pre-conveying pattern and the post-conveying pattern of the plurality of correction patterns is formed at the same position in the carrying direction, and the other pattern is different from the carrying direction It is preferable that the nozzle that is formed at the position and forms the other pattern of the correction pattern is different from the nozzle that forms the other pattern of the other correction pattern. According to such a printing apparatus, since the positions of the nozzles used in forming each correction pattern in the transport direction are different, the positions of the formed patterns in the transport direction are different. The nozzle is capable of forming a plurality of sized dots on the medium, and at least one of the pre-carrying pattern and the post-carrying pattern is composed of the plurality of sized dots. Is preferred. The optimal correction pattern for test patterns consisting of only large dots may differ from the optimal correction pattern for test patterns consisting of only small dots due to the effects of ink drying and ink bleeding. Therefore, according to such a printing apparatus, it becomes possible to select an optimal correction pattern using a test pattern composed of dots of different sizes, and thus an average correction amount can be specified. Can do. Moreover, it is preferable that at least one of the pre-transport pattern and the post-transport pattern is composed of a plurality of dots of different colors. Since the optimum correction pattern of the test pattern composed only of each color may be different due to the influence of the nozzle mounting error of each color and the tolerance of dimensions, according to such a printing device, the dots of different colors If an optimal correction pattern is selected using the test pattern configured from the above, an average correction amount can be specified. The length in the transport direction of the region where the plurality of correction patterns is formed is preferably shorter than twice the length from the most upstream nozzle to the most downstream nozzle among the plurality of nozzles. According to such a printing apparatus, a large number of correction patterns can be formed in a narrow region where only one correction pattern can be formed in the transport direction.

  In this printing apparatus, the transport unit includes an upstream roller located on the upstream side of the printing area, and a downstream roller located on the downstream side of the printing area, and the upstream roller and the downstream side It is preferable that the correction pattern is formed on the medium when the medium is conveyed by one of the rollers. The conveyance state by two rollers and the conveyance state by one roller are different conveyance states. According to this printing apparatus, a large number of correction patterns can be formed in a narrow printing region where a medium is conveyed by one roller. The correction amount for the conveyance amount when the medium is conveyed using the upstream roller and the downstream roller is different from the correction amount for the conveyance amount when the medium is conveyed using the one roller. It is preferable. Since the conveyance state by two rollers and the conveyance state by one roller are different conveyance states, a correction amount corresponding to each conveyance state is set. The shape of the downstream roller is preferably different from the shape of the upstream roller. If the shapes of the two rollers are different, the conveyance state by two rollers and the conveyance state by one roller are different conveyance states. According to this printing apparatus, a large number of correction patterns can be formed in a narrow printing region where a medium is conveyed by one roller. The shape of the driven roller facing the downstream roller is preferably different from the shape of the driven roller facing the upstream roller. If the shape of each driven roller is different, the conveying state by two rollers and the conveying state by one roller are different. According to this printing apparatus, a large number of correction patterns can be formed in a narrow printing region where a medium is conveyed by one roller. The conveyance speed of the downstream roller is preferably different from the conveyance speed of the upstream roller. If the conveyance speeds of the two rollers are different, the conveyance state by two rollers and the conveyance state by one roller are different conveyance states. According to this printing apparatus, a large number of correction patterns can be formed in a narrow printing region where a medium is conveyed by one roller.

  In this printing apparatus, the transport unit includes an upstream roller located on the upstream side of the printing area, and a downstream roller located on the downstream side of the printing area, and the upstream roller and the downstream side When the medium is conveyed by a roller, the correction pattern may be formed on the medium. As described above, in this printing apparatus, the state when the correction pattern is formed is not limited to the state in which the correction pattern is conveyed by one of the two rollers.

  In this printing apparatus, it is preferable that the one pattern of a certain correction pattern is formed on the medium apart from the one pattern of another correction pattern. Such a printing apparatus is convenient when the user selects an optimal correction pattern from a plurality of correction patterns. However, the one pattern of a certain correction pattern may be formed on the medium integrally with the one pattern of another correction pattern.

  In this printing apparatus, it is preferable that the transport unit transports a plurality of times between the formation of the pre-transport pattern and the formation of the post-transport pattern. According to such a printing apparatus, it is possible to detect transport errors accumulated during a plurality of transports performed between the formation of the pre-transport pattern and the post-transport pattern.

  In such a printing apparatus, it is desirable that a code for identifying the correction pattern is attached to each correction pattern. Such a printing apparatus is convenient when the user selects an optimal correction pattern from among a plurality of correction patterns. The code is preferably formed together when forming the pre-transport pattern. According to such a printing apparatus, a large number of correction patterns can be formed in a narrow print region, and a code for identifying the correction pattern can be formed. It is preferable that the code is formed adjacent to the conveyance direction of the correction pattern. According to such a printing apparatus, since the interval between the plurality of correction patterns can be shortened, many correction patterns can be formed in a narrow print region.

A test in which a plurality of correction patterns each having a pre-transport pattern formed before being transported and a post-transport pattern formed after being transported and formed adjacent to the transport direction and the post-transport pattern are printed. A pattern,
A test pattern, wherein a plurality of the correction patterns are arranged in a direction intersecting the transport direction and formed on the medium.
According to such a test pattern, more correction patterns can be formed in a narrow area on the medium.

A test pattern manufacturing method for printing a correction pattern having a pattern before conveyance and a pattern after conveyance on a plurality of media,
Forming a pre-transport pattern before transporting the medium;
Conveying the medium;
Forming a pattern before transport and a pattern after transport adjacent to the transport direction after transporting the medium;
A test pattern manufacturing method, wherein a plurality of the correction patterns are arranged in a direction intersecting with the transport direction and formed on the medium.
According to such a test pattern manufacturing method, more correction patterns can be formed in a narrow area on the medium.

=== Configuration of Printing System ===
Next, an embodiment of a printing system (computer system) will be described with reference to the drawings. However, the description of the following embodiments includes embodiments relating to a computer program and a recording medium on which the computer program is recorded.

  FIG. 1 is an explanatory diagram showing an external configuration of a printing system. The printing system 100 includes a printer 1, a computer 110, a display device 120, an input device 130, and a recording / reproducing device 140. The printer 1 is a printing apparatus that prints an image on a medium such as paper, cloth, or film. The computer 110 is electrically connected to the printer 1 and outputs print data corresponding to the image to be printed to the printer 1 in order to cause the printer 1 to print an image. The display device 120 has a display and displays a user interface such as an application program or a printer driver. The input device 130 is, for example, a keyboard 130A or a mouse 130B, and is used for operating an application program, setting a printer driver, or the like along a user interface displayed on the display device 120. As the recording / reproducing device 140, for example, a flexible disk drive device 140A or a CD-ROM drive device 140B is used.

  A printer driver is installed in the computer 110. The printer driver is a program for realizing the function of displaying the user interface on the display device 120 and the function of converting the image data output from the application program into print data. This printer driver is recorded on a recording medium (computer-readable recording medium) such as a flexible disk FD or a CD-ROM. Alternatively, the printer driver can be downloaded to the computer 110 via the Internet. In addition, this program is comprised from the code | cord | chord for implement | achieving various functions.

  The “printing apparatus” means the printer 1 in a narrow sense, but means a system of the printer 1 and the computer 110 in a broad sense.

=== Configuration of Printer ===
<Inkjet printer configuration>
FIG. 2 is a block diagram of the overall configuration of the printer of this embodiment. FIG. 3 is a schematic diagram of the overall configuration of the printer of this embodiment. FIG. 4 is a cross-sectional view of the overall configuration of the printer of this embodiment. Hereinafter, the basic configuration of the printer of this embodiment will be described.

  The printer of this embodiment includes a transport unit 20, a carriage unit 30, a head unit 40, a sensor 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 forms an image on paper. The situation in the printer 1 is monitored by a sensor 50, and the sensor 50 outputs a detection result to the controller 60. The controller that receives the detection result from the sensor controls each unit based on the detection result.

  The transport unit 20 is for feeding a medium (for example, the paper S) to a printable position and transporting the paper by a predetermined transport amount in a predetermined direction (hereinafter referred to as a transport direction) during printing. That is, the transport unit 20 functions as a transport mechanism (transport means) that transports paper. 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. However, in order for the transport unit 20 to function as a transport mechanism, all of these components are not necessarily required. The paper feed roller 21 is a roller for automatically feeding the paper inserted into the paper insertion slot into the printer. The paper feed roller 21 has a D-shaped cross section, and the length of the circumferential portion is set to be longer than the transport distance to the transport roller 23. 23 can be conveyed. The transport motor 22 is a motor for transporting paper in the transport direction, and is constituted by a DC motor. 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 printed paper S to the outside of the printer. The paper discharge roller 25 rotates in synchronization with the transport roller 23.

  The carriage unit 30 is for moving (scanning) the head in a predetermined direction (hereinafter referred to as a scanning 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 scanning direction. (Thus, the head moves along the scanning direction.) The carriage 31 detachably holds an ink cartridge that stores ink. The carriage motor 32 is a motor for moving the carriage 31 in the scanning direction, and is constituted by a DC motor.

  The head unit 40 is for ejecting ink onto paper. The head unit 40 has a head 41. The head 41 has a plurality of nozzles that are ink discharge portions, and discharges ink intermittently from each nozzle. The head 41 is provided on the carriage 31. Therefore, when the carriage 31 moves in the scanning direction, the head 41 also moves in the scanning direction. Then, when the head 41 is intermittently ejected while moving in the scanning direction, dot lines (raster lines) along the scanning direction are formed on the paper.

  The sensor 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 is for detecting the position of the carriage 31 in the scanning direction. The rotary encoder 52 is for detecting the rotation amount of the transport roller 23. The paper detection sensor 53 is for detecting the position of the leading edge of the paper to be printed. The paper detection sensor 53 is provided at a position where the position of the leading edge of the paper can be detected while the paper feed roller 21 feeds the paper toward the transport roller 23. The paper detection sensor 53 is a mechanical sensor that detects the leading edge of the paper by a mechanical mechanism. More specifically, the paper detection sensor 53 has a lever that can rotate in the transport direction, and this lever is disposed so as to protrude into the paper transport path. For this reason, since the leading edge of the paper comes into contact with the lever and the lever is rotated, the paper detection sensor 53 detects the position of the leading edge of the paper by detecting the movement of the lever. The optical sensor 54 is attached to the carriage 31. The optical sensor 54 detects the presence or absence of paper by the light receiving unit detecting reflected light of light irradiated on the paper from the light emitting unit. The optical sensor 54 detects the position of the edge of the paper while being moved by the carriage 41. Since the optical sensor 54 optically detects the edge of the paper, the detection accuracy is higher than that of the mechanical paper detection sensor 53.

  The controller 60 is a control unit (control means) 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 is for transmitting and receiving 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 the program of the CPU 62, a work area, and the like, and has storage means 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 printing operation>
FIG. 5 is a flowchart of processing during printing. Each process described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  The controller 60 receives a print command from the computer 110 via the interface unit 61 (S001). This print command is included in the header of print data transmitted from the computer 110. Then, the controller 60 analyzes the contents of various commands included in the received print data, and performs the following paper feed processing, transport processing, ink ejection processing, and the like using each unit.

  First, the controller 60 performs a paper feed process (S002). The paper feed process is a process of supplying paper to be printed into the printer and positioning the paper at a print start position (also referred to as a cue position). The controller 60 rotates the paper feed roller 21 and sends the paper to be printed to the transport roller 23. The controller 60 rotates the transport roller 23 to position the paper fed from the paper feed roller 21 at the print start position. When the paper is positioned at the print start position, at least some of the nozzles of the head 41 are opposed to the paper.

  Next, the controller 60 performs dot formation processing (S003). The dot formation process is a process for forming dots on paper by intermittently ejecting ink from a head that moves in the scanning direction. The controller 60 drives the carriage motor 32 to move the carriage 31 in the scanning direction. Then, the controller 60 ejects ink from the head based on the print data while the carriage 31 is moving. When ink droplets ejected from the head land on the paper, dots are formed on the paper.

  Next, the controller 60 performs a conveyance process (S004). The conveyance process is a process of moving the paper relative to the head along the conveyance direction. The controller 60 drives the carry motor and rotates the carry roller to carry the paper in the carrying direction. By this carrying process, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation process.

  Next, the controller 60 determines whether or not to discharge the paper being printed (S005). If there is still data to be printed on the paper being printed, no paper is discharged. Then, the controller 60 alternately repeats the dot formation process and the conveyance process until there is no data to be printed, and gradually prints an image composed of dots on paper. When there is no more data for printing on the paper being printed, the controller 60 discharges the paper. The controller 60 discharges the printed paper to the outside by rotating the paper discharge roller. The determination of whether or not to discharge paper may be based on a paper discharge command included in the print data.

  Next, the controller 60 determines whether or not to continue printing (S006). If printing is to be performed on the next paper, printing is continued and the paper feeding process for the next paper is started. If printing is not performed on the next paper, the printing operation is terminated.

<About nozzle>
FIG. 6 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 a plurality of nozzles (180 in this embodiment) 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) along the transport direction. In this embodiment, the nozzle pitch is 180 dpi (1/180 inch).

  The nozzles in each nozzle group are assigned a lower number in the downstream nozzle (# 1 to # 180). That is, the nozzle # 1 is located downstream of the nozzle # 180 in the transport direction. Each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets. Further, the optical sensor 54 is substantially at the same position as the nozzle # 180 on the most upstream side with respect to the position in the paper transport direction.

<About driving the head>
FIG. 7 is an explanatory diagram of the drive circuit of the head unit 40. This drive circuit is provided in the unit control circuit 64 described above, and includes an original drive signal generation unit 644A and a drive signal shaping unit 644B, as shown in FIG. Such drive circuits for the nozzles # 1 to # 180 are provided for each nozzle group, that is, for each nozzle group of black (K), cyan (C), magenta (M), and yellow (Y). Yes. In addition, the piezo elements are individually driven for each nozzle. In the figure, the numbers in parentheses at the end of each signal name indicate the number of the nozzle to which the signal is supplied.

  When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts in accordance with the expansion and contraction of the piezo element, and the ink amount corresponding to the contraction is ejected from the nozzles # 1 to # 180 of the respective colors as ink droplets.

  The original drive signal generator 644A generates an original signal ODRV that is used in common by the nozzles # 1 to # 180. The original signal ODRV is a signal including a plurality of pulses within the main scanning period for one pixel (within the time during which the carriage 41 crosses the interval of one pixel).

  The drive signal shaping unit 644B receives the original signal ODRV from the original signal generation unit 644A and the print signal PRT (i). The drive signal shaping unit 644B shapes the original signal ODRV according to the level of the print signal PRT (i), and outputs it as the drive signal DRV (i) toward the piezoelectric elements of the nozzles # 1 to # 180. The piezoelectric elements of the nozzles # 1 to # 180 are driven based on the drive signal DRV from the drive signal shaping unit 644B.

<About the head drive signal>
FIG. 8 is a timing chart for explaining each signal. In other words, the timing chart of each signal of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i) is shown in FIG.

  The original signal ODRV is a signal that is commonly supplied from the original signal generator 644A to the nozzles # 1 to # 180. In the present embodiment, the original signal ODRV includes two pulses of a first pulse W1 and a second pulse W2 within a main scanning period for one pixel (within a time during which the carriage crosses the interval of one pixel). The original signal ODRV is output from the original signal generation unit 644A to the drive signal shaping unit 644B.

  The print signal PRT is a signal corresponding to pixel data assigned to one pixel. That is, the print signal PRT is a signal corresponding to the pixel data included in the print data. In the present embodiment, the print signal PRT (i) is a signal having 2-bit information for one pixel. Note that the drive signal shaping unit 644B shapes the original signal ODRV according to the signal level of the print signal PRT and outputs the drive signal DRV.

  The drive signal DRV is a signal obtained by blocking the original signal ODRV according to the level of the print signal PRT. That is, that is, when the print signal PRT is 1 level, the drive signal shaping unit 644B passes the corresponding pulse of the original signal ODRV as it is as the drive signal DRV. On the other hand, when the print signal PRT is 0 level, the drive signal shaping unit 644B blocks the pulse of the original signal ODRV. The drive signal shaping unit 644B outputs the drive signal DRV to the piezo element provided for each nozzle. The piezo element is driven according to the drive signal DRV.

  When the print signal PRT (i) corresponds to the 2-bit data “01”, only the first pulse W1 is output in the first half of one pixel section. As a result, small ink droplets are ejected from the nozzles, and small dots (small dots) are formed on the paper. When the print signal PRT (i) corresponds to the 2-bit data “10”, only the second pulse W2 is output in the latter half of one pixel section. As a result, medium-sized ink droplets are ejected from the nozzles, and medium-sized dots (medium dots) are formed on the paper. When the print signal PRT (i) corresponds to the 2-bit data “11”, the first pulse W1 and the second pulse W2 are output in one pixel section. Thereby, a large ink droplet is ejected from the nozzle, and a large dot (large dot) is formed on the paper.

  As described above, the drive signal DRV (i) in one pixel section is shaped so as to have three different waveforms according to three different values of the print signal PRT (i).

=== Conveyance processing ===
<About transport processing>
FIG. 9 is an explanatory diagram of the configuration of the transport unit 20. In these drawings, the components already described are given the same reference numerals and the description thereof is omitted.

The transport unit 20 drives the transport motor 22 by a predetermined drive amount based on a transport command from the controller. 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. Further, the transport motor 22 rotates the paper discharge roller 25 using this driving force. That is, when the transport motor 22 generates a predetermined drive amount, the transport roller 23 and the paper discharge roller 25 rotate by a predetermined rotation amount. When the transport roller 23 and the paper discharge roller 25 are rotated by a predetermined rotation amount, the paper is transported by a predetermined transport amount. Since the transport roller 23 and the paper discharge roller 25 rotate in synchronization, the paper can be transported by the transport unit 20 as long as the paper is in contact with at least one of the transport roller 23 and the paper discharge roller 25.
The carry amount of the paper is determined according to the rotation amount of the carry roller 23. 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.

<About the configuration of the rotary encoder>
FIG. 10 is an explanatory diagram of the configuration of the rotary encoder. In these drawings, the components already described are given the same reference numerals and the description thereof is omitted.

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 14. That is, the scale 521 rotates together when the transport roller 23 rotates. For example, when the transport roller 23 rotates to transport the paper S for 1/1440 inch, the scale 521 rotates by one slit relative to 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 detection unit 522 includes a light emitting diode 522A, a collimator lens 522B, and a detection processing unit 522C. The detection processing unit 522C includes a plurality of (for example, four) photodiodes 522D and a signal processing circuit 522E. Two comparators 522Fa and 522Fb are provided.

  The light emitting diode 522A emits light when a voltage Vcc is applied through resistances at both ends, and this light enters the collimator lens. The collimator lens 522B converts the light emitted from the light emitting diode 522A into parallel light, and irradiates the scale 521 with the parallel light. The parallel light that has passed through the slit provided in the scale passes through a fixed slit (not shown) and enters each photodiode 522D. The photodiode 522D converts incident light into an electrical signal. The electric signals output from the photodiodes are compared in the comparators 522Fa and 522Fb, and the comparison result is output as a pulse. The pulses ENC-A and ENC-B output from the comparators 522Fa and 522Fb are the output of the rotary encoder 52.

<About rotary encoder signals>
FIG. 11A is a timing chart of the waveform of the output signal when the transport motor 22 is rotating forward. FIG. 11B is a timing chart of the waveform of the output signal when the conveyance motor 22 is reversed.

  As shown in the figure, the phase of the pulse ENC-A and the pulse ENC-B are shifted by 90 degrees regardless of whether the conveyance motor 12 is rotating forward or reversing. When the transport motor 22 is rotating forward, that is, when the paper S is transported in the transport direction, the phase of the pulse ENC-A is advanced by 90 degrees from the pulse ENC-B. On the other hand, when the transport motor 22 is reversed, that is, when the paper S is transported in the direction opposite to the transport direction, the phase of the pulse ENC-A is delayed by 90 degrees from the pulse ENC-B. Yes. One period T of each pulse is equal to a time during which the transport roller 23 rotates by an interval between slits of the scale 521 (for example, 1/1440 inch (1 inch = 2.54 cm)).

  If the controller counts the number of pulse signals, the rotation amount of the conveyance roller 23 can be detected, so that the conveyance amount of the paper can be detected. Further, if the controller detects one cycle T of each pulse, the rotational speed of the transport roller 23 can be detected, so that the paper transport speed can be detected.

<About transfer flow>
FIG. 12 is a flowchart of the conveyance process. Various operations described below are realized by the controller controlling the transport unit 20 based on a program stored in a memory in the printer 1. The program is composed of codes for performing various operations described below.

  First, the controller sets a target carry amount (S041). The target transport amount is a value that determines the drive amount of the transport unit 20 because the transport unit 20 transports the paper S with the target transport amount. This target carry amount is determined based on carry command data (information relating to the target carry amount) included in the print data received from the computer side. The target transport amount is set by setting a counter value by the controller. In the following description, since the target transport amount is X, the controller sets the counter value to X.

  Next, the controller drives the carry motor 22 (S042). When the transport motor 22 generates a predetermined drive amount, the transport roller 23 rotates with a predetermined rotation amount. When the transport roller 23 rotates by a predetermined rotation amount, the slit 521 provided on the transport roller 23 also rotates.

  Next, the controller detects the edge of the pulse signal of the rotary encoder (S043). That is, the controller detects a rising edge or a falling edge for the pulse ENC-A or ENC-B. For example, if the controller detects one edge, it means that the transport roller 23 transported the paper S by a transport amount of 1/1440 inch.

  When the controller detects the edge of the pulse signal of the rotary encoder, the controller subtracts the value of the counter (S044). That is, when the counter value is X and the controller detects one edge of the pulse signal, the controller sets the counter value to X-1.

  Then, the controller repeats the operations of S042 to S044 until the counter value becomes zero (S045). That is, the controller drives the carry motor 22 until the number of pulses of the value set in the counter is detected first. As a result, the transport unit 20 transports the paper S in the transport direction by the transport amount corresponding to the value initially set in the counter.

  For example, when the transport unit 20 transports the paper S by 90/1440 inches, the controller sets the counter value to 90 in order to set the target transport amount. The controller subtracts the value of the counter every time the rising edge or the falling edge of the pulse signal of the rotary encoder is detected. Then, when the value of the counter becomes zero, the controller ends the carrying operation. This is because if 90 pulse signals are detected, it means that the transport roller 23 transports the paper S at 90/1440 inches. Therefore, if the controller sets the counter value to 90 as the setting of the target carry amount, the carry unit 20 carries the paper S at 90/1440 inches.

  In the above description, the controller detects the rising edge or falling edge of the pulse ENC-A or ENC-B. However, the controller may detect both edges of the pulse ENC-A and the pulse ENC-B. good. The period of each of the pulses ENC-A and ENC-B is equal to the slit interval of the scale 521, and the phases of the pulses ENC-A and ENC-B are shifted by 90 degrees. Detecting either the edge or the falling edge means that the transport roller 23 transports the paper at 1/5760 inch. In this case, if the controller sets the counter value to 90, the transport unit 20 transports the paper S at 90/5760 inches.

  The above description relates to one transport operation. When the printer performs a plurality of transport operations intermittently, the controller sets a target transport amount (sets a counter value) at the end of each transport operation, and the transport unit 20 follows the set target transport amount. The paper S is conveyed.

  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. That is, if there is a slip between the transport roller 23 and the paper S, the rotary encoder 52 accurately detects the transport amount of the paper S because the rotation amount of the transport roller 23 and the transport amount of the paper S do not match. Cannot be performed, and a conveyance error (detection error) occurs. As described above, when slippage occurs between the transport roller 23 and the paper S, the controller transports the paper S with a transport amount larger than the target transport amount in order for the transport unit 20 to transport the paper S with the target transport amount. It is necessary to rotate the roller 23. Therefore, the controller can correct the target carry amount and set the counter to a value corresponding to the corrected target carry amount in order to carry the paper S by the optimum carry amount.

  In the embodiment described below, it is assumed that the rotary encoder can detect the rotation amount of the transport roller 23 in units of 1/5760 inch. In addition, the controller corrects the target carry amount by using 1/5760 inch as a unit of the minimum correction amount.

=== Method for Determining Correction Amount ===
First, it is necessary to determine in advance a correction amount for the target transport amount before shipment of the printer or at the user site. Therefore, a correction amount determination method will be described below.

<About the procedure for determining the correction amount>
FIG. 13 is a flowchart for explaining the procedure for determining the correction amount. Various operations of the printer described below are realized by programs stored in the memory 63 in the printer. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

  First, the printer receives an instruction signal for instructing printing of a test pattern for carrying amount correction (S101). This instruction signal may be received from the computer main body or may be input from a button provided on the printer main body. When an instruction to print a test pattern is issued from the computer main body, for example, a user interface as shown in FIG. 14 is displayed on a display device connected to the computer main body. In the window W1 displayed on the display device, a button for instructing printing of a test pattern for carrying amount correction is displayed. When the user clicks this button, a signal instructing printing of the test pattern is transmitted from the computer main body to the printer 1 side.

  Next, the printer prints a test pattern for carrying amount correction (S102). The printer that has received the instruction signal searches the test pattern in the memory 63 for information related to the transport amount correction test pattern. Then, the printer prints the test pattern on the paper S in accordance with the information related to the conveyance amount correction test pattern.

  FIG. 15 is an example of a test pattern for carrying amount correction printed on the paper S. The test pattern printed on paper has a plurality of correction patterns. For example, in the present embodiment, the test pattern printed on paper has five correction patterns. The correction pattern has two strip patterns. Hereinafter, the upper band-like pattern of the correction pattern is referred to as a first band pattern, and the lower pattern of the correction pattern is referred to as a second band pattern. The distance between the first band pattern and the second band pattern is different for each correction pattern. As a result, each correction pattern corresponds to a specific correction amount. For example, in the present embodiment, in order from the left correction pattern, the distance between the first band pattern and the second band pattern decreases, and the corresponding correction amount also decreases. Depending on the distance between the first band pattern and the second band pattern, white stripes (also called white banding or light banding) or black stripes (black banding or dark banding) between the first band pattern and the second band pattern. Called banding). However, in the correction pattern corresponding to the optimum correction amount, a striped pattern does not occur so much between the first band pattern and the second band pattern. For example, in the present embodiment, the striped pattern does not occur so much in the correction pattern assigned “number = 2”. A method of printing a test pattern for carrying amount correction will be described later.

  After printing the transport amount correction test pattern, the user selects an optimal correction pattern from a plurality of correction patterns printed as test patterns (S103). This optimum pattern selection may be performed on the computer main body side or on the printer main body side. When selecting an optimum pattern on the computer main body side, for example, a user interface as shown in FIG. 16 is displayed on a display device connected to the computer main body. In the window W2 displayed on the display device, a plurality of buttons are displayed so as to correspond to the plurality of printed correction patterns. When the user clicks this button, the correction pattern corresponding to the clicked button is selected as the optimum pattern. For example, in the present embodiment, the user clicks a button corresponding to “number = 2”.

  Next, the correction amount for correcting the carry amount is saved (stored) in the printer (S104). When the optimum pattern is selected on the computer main body side, information on the correction amount corresponding to the optimum pattern (information on the carry amount) is transmitted from the computer main body side to the printer side. Then, the printer stores the received information regarding the correction amount in the memory 63 in the printer.

<Correction of target transport amount>
FIG. 17 is a flowchart for explaining a flow when an image is formed on paper. Various operations of the printer described below are realized by programs stored in the memory 63 in the printer. Various operations of the computer main body described below are realized by a printer driver which is a program stored in the computer main body. These programs are composed of codes for performing various operations described below.

First, the user turns on the printer and puts the printer in a print standby state (S211).
Then, the user gives a print instruction from an application operating on the computer side (S201). When the user gives a print instruction to the computer, the print mode (printing method) is set via the user interface of the printer driver. Then, the printer driver can determine the target carry amount based on the set print mode (S202). Also, image data to be printed is converted into pixel data by the printer driver. This pixel data is data for pixels corresponding to the resolution of the set print mode.
Then, the printer driver transmits print data including data relating to the target carry amount and pixel data to the printer side (S203).

  The printer that has received the print data reads information regarding the correction amount stored in the memory (S212). Next, the printer corrects the target carry amount based on the read correction amount (S213). Then, based on the corrected target transport amount, a counter value set in the transport process is determined. For example, when the paper S is transported for 1 inch, the value of the counter is 5760 unless the target transport amount is corrected, but the correction amount stored in the memory is “+ C (= + 1/5760 inch)”. In the corresponding case, the value of the counter is 5761 (= 5760 + 1). Then, the printer performs a printing process with the corrected target carry amount according to the print data (S214). For example, even if the conveyance processing is performed with the counter value of 5761, the conveyance error and the correction amount are offset, and the actual conveyance amount of the paper S becomes 1 inch. Since the printing process is performed while transporting the paper S according to the corrected target transport amount, the interval in the transport direction of the dots formed on the paper S becomes appropriate, so that a highly accurate image can be printed on the paper S. it can.

=== Reference explanation ===
<Test pattern of reference example>
FIG. 18 is an explanatory diagram of a test pattern printing method in the reference example. The test pattern printing method of the reference example described below is performed at S102 described above. Note that the rectangles 41A to 41F drawn on the left side in the figure indicate the position of the head 41 with respect to the paper S, and are not printed on the paper S. The number in the rectangle representing the head 41 indicates the relative position of the head in the number of passes (the pass means the dot forming process in S003). For example, the head 41C in the figure indicates the relative position of the head 41 in the third pass. In this figure, the head 41 appears to move with respect to the paper S, but this figure shows the relative position between the head 41 and the paper S, and the paper S is actually transported in the transport direction. As a result, the relative positions of the two have moved.

  Each correction pattern of the test pattern of the reference example is composed of two strip patterns (band patterns). Of the two band patterns, the band pattern (first band pattern) on the paper leading end side (upper side in the figure) is formed by nozzles on the upstream side (nozzle # 180 side) in the transport direction. On the other hand, the band pattern (second band pattern) on the paper rear end side (lower side in the figure) of the two band patterns is formed by nozzles on the downstream side (nozzle # 1 side) in the transport direction. The first band pattern and the second band pattern are formed adjacent to each other in the transport direction, and a boundary portion is configured by the two band patterns. In this way, the paper S is conveyed by the width of the head 41 approximately between the formation of the first band pattern and the formation of the second band pattern. Further, the two band patterns are formed so as to be shifted in the scanning direction so that the position of the boundary portion constituted by the two band patterns becomes clear. The numbers in the rectangles representing the band patterns in the figure indicate the number of passes formed.

  Since each correction pattern is formed by changing the carry amount in stages, the state of the boundary portion between the band patterns of each correction pattern is different. Therefore, each correction pattern (or boundary portion) corresponds to a different correction amount. In the test pattern printing method of the reference example, as described below, a plurality of correction patterns (that is, boundary portions) are formed by changing the conveyance amount in steps of C (= 1/5760 inch). Yes.

  First, the paper S is transported so that the head 41 is positioned at the head 41 </ b> A with respect to the paper S. Then, the first printing operation (pass 1) is performed, and the first band pattern P1a of the correction pattern P1 to which “number = 1” is attached is printed.

  Next, the paper S is transported by the target transport amount F + 2C, and the head 41 is positioned with respect to the paper S as the head 41B in the drawing. Here, the target carry amount F is a carry amount substantially corresponding to the width of the head 41. For example, when 180 nozzles are arranged in the head 31 at intervals of 180 dpi, the target carry amount F is 1 inch. Then, the second dot formation process (pass 2) is performed, and the second band pattern P1b of the correction pattern P2 to which “number = 1” is attached is printed. Thereby, the correction pattern P1 to which “number = 1” is attached is completed. When the second pass (pass 2: second dot formation process) is performed, the second band pattern P1b is printed, and the first band pattern P2a of the correction pattern P2 to which “number = 2” is attached. Is printed. That is, in the second pass, two band patterns (P1b and P2a) are printed. These two band patterns are formed with a blank space.

  Next, the paper S is transported by the target transport amount F + C, and the head 41 is in the position of the head 41C in the drawing with respect to the paper S. Then, the third dot formation process (pass 3) is performed, and the second band pattern P2b of the correction pattern P2 to which “number = 2” is attached is printed. Thereby, the correction pattern P2 to which “number = 2” is attached is completed. When the third pass (pass 3: third dot formation process) is performed, the second band pattern P2b is printed, and the first band pattern P3a of the correction pattern P3 to which “number = 3” is attached. Is printed. That is, in the third pass, two band patterns (P2b and P3a) are printed. These two band patterns are formed with a blank space.

  Then, the other correction patterns P3 to P5 are printed on the paper S by substantially the same operation as described above. However, the target transport amount when transporting the paper S changes stepwise by C (= 1/5760 inch) every time the paper S is transported by the width of the head. As a result, printing is performed so that the interval between the first band pattern and the second band pattern differs depending on each correction pattern.

  In the test pattern printing method of the reference example, a plurality of correction patterns (P1 to P5) are printed by repeatedly carrying a carry amount substantially equal to the head width. Thereby, the plurality of correction patterns (P1 to P5) printed on the paper S are arranged in the transport direction. As a result, in order to print the test pattern of the reference example, it is necessary to ensure a wide print area in the transport direction.

<Difficulty of printing test patterns at the bottom>
FIG. 19A is an explanatory diagram of a normal transport process. FIG. 19B is an explanatory diagram of the transport process after the trailing edge of the paper has passed the transport roller. In the figure, the same reference numerals are given to the components already described, and the description thereof is omitted.

  A conveyance roller 23 (upstream roller) positioned upstream of the printing area and a paper discharge roller 25 (downstream roller) positioned downstream of the printing area rotate synchronously. During normal transport processing, the paper S is transported by two rollers, a transport roller 23 and a paper discharge roller 25. In the conveyance of the paper S, this normal conveyance process is almost all. That is, a wide print area with this normal transport process is secured. Therefore, the correction amount of the target carry amount in the normal carrying process can be determined by printing the test pattern of the reference example described above.

  However, the conveyance state before and after the trailing edge of the paper S passes through the conveyance roller 23 is different. For example, after the trailing edge of the paper S has passed the transport roller 23, the paper S is transported only by the paper discharge roller 25, so that the paper is transported by two rollers (normal transport state) and Will be in different states. Further, the shapes (for example, radius and cross-sectional shape) of the transport roller 23 and the paper discharge roller 25 are different. Further, the roller provided opposite to the paper discharge roller 25 has a different shape from the driven roller on the transport roller 23 side in order to reduce contact with the printing surface. In order to prevent paper from being wrinkled during normal conveyance, the conveyance speed on the paper discharge roller 25 side is designed to be slightly higher than the conveyance speed on the conveyance roller 23 side. Due to these factors, the transport state after the trailing edge of the paper S passes the transport roller 23 is different from the normal transport state.

  For this reason, even if the paper S is transported with the same target transport amount, the transport amount of the paper after the trailing end of the paper S passes the transport roller 23 is different from the transport amount of the paper during normal transport. That is, after the trailing edge of the paper S passes the transport roller 23, even if the target transport amount is corrected based on the correction amount for the normal transport process, suitable transport is not performed (the state where there is a transport error). The paper S is transported). Therefore, after the trailing edge of the paper S passes through the conveyance roller 23, it is necessary to correct the target conveyance amount based on the correction amount for the conveyance processing of the trailing edge of the paper S.

Therefore, in order to determine the correction amount at the time of carrying processing of the trailing edge of the paper S, it is necessary to print a test pattern. However, the test pattern for determining the correction amount for the conveyance process at the trailing edge of the paper S needs to be printed in the same state as that for the conveyance process at the trailing edge of the paper S. That is, this test pattern must be printed after the trailing edge of the paper S has passed the transport roller 23.
However, when the trailing edge of the paper S passes the transport roller 23, the area where the printer can print on the paper S is narrow.

  FIG. 20 is an explanatory diagram of the positional relationship between the paper and the head when the trailing edge of the paper passes the transport roller 23. In the figure, the same reference numerals are given to the components already described, and the description thereof will be omitted.

  The hatched portion in the figure indicates an area where the head 41 can print after the trailing edge of the paper has passed the transport roller 23. Only the length L is secured in the hatched printing area in the transport direction. The length L is determined according to the design position of the components of the printer (particularly the head 41 and the transport roller 23). Usually, in order to make the printer 1 small, the positions of the head 41 and the transport roller 23 are close to each other, so the length L is the width of the head (from # 180 being the most upstream nozzle to # 1 being the most downstream nozzle). Is less than twice the length). In the present embodiment, the width F of the head 41 is 1 inch (= 2.54 cm), and the length L is about 3.5 cm.

As described above, the area where the head 41 can print after the trailing edge of the paper passes through the conveyance roller 23 is a narrow area in the conveyance direction. Since the test pattern printing requires a wide print area in the transport direction, the test pattern cannot be printed after the trailing edge of the paper has passed the transport roller 23. Even if an attempt is made to print the test pattern of the reference example in the printing region having the length L in the transport direction, only one correction pattern can be printed.
Therefore, in this embodiment, the test pattern is printed as follows.

=== Test Pattern Printing of this Embodiment ===
<Test pattern printing method>
First, a test pattern printing method according to the present embodiment will be described with reference to FIGS. 21 and 22. Each operation described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  FIG. 21 is an explanatory diagram of a test pattern printing method according to the present embodiment. The test pattern printing method of the present embodiment described below is performed at S102 described above. Note that rectangles 41A to 41H drawn on the left side in the drawing indicate the position of the head 41 with respect to the paper S, and are not printed on the paper S. The number in the rectangle representing the head 41 indicates the relative position of the head in the number of passes (the pass means the dot forming process in S003). However, in the present embodiment, the first dot forming process after the trailing edge of the paper S has passed the transport roller is referred to as a “first pass”. For example, the head 41C in the figure indicates the relative position of the head 41 in the third pass after the trailing edge of the paper S has passed the transport roller. On the other hand, when no numeral is written in the rectangle, it means that the dot formation process is not performed when the head 41 is positioned at the position of the rectangle. In this figure, the head 41 appears to move with respect to the paper S, but this figure shows the relative position between the head 41 and the paper S, and the paper S is actually transported in the transport direction. As a result, the relative positions of the two have moved.

  In the present embodiment, the test pattern printed on paper has five correction patterns. Each correction pattern is composed of a first band pattern and a second band pattern which are two band-like patterns (band patterns). Here, the band pattern on the leading end side (upper side in the figure) of the paper S is called a first band pattern, and the band pattern on the rear end side (lower side in the figure) of the paper S is called a second band pattern. The first band pattern and the second band pattern are formed adjacent to each other in the transport direction, and a boundary portion is configured by the two band patterns. Further, the two band patterns are formed so as to be shifted in the scanning direction so that the position of the boundary portion constituted by the two band patterns becomes clear. The numbers in the rectangles representing the band patterns in the figure indicate the number of passes formed. As will be apparent from the following description, in the present embodiment, the first band pattern is a pre-transport pattern formed before transport by the transport unit, and the second band pattern is formed after transport by the transport unit. It is a pattern after conveyance.

  FIG. 22 is an explanatory diagram of the positional relationship between nozzles and paper in the test pattern printing method of the present embodiment. This figure shows the relative position between the head 41 and the paper S. In actuality, the relative position of the paper S is moved as the paper S is transported in the transport direction. In the present embodiment, the head 41 has a plurality of nozzle groups corresponding to the type of ink to be ejected, and each nozzle group has 180 nozzles along the transport direction. However, here, in order to simplify the description, the relative position between one nozzle group and the paper S will be described. The nozzles of the nozzle group are aligned at an interval of 180 dpi (= 1/180 inch) along the transport direction. The numbers in the circles in the figure indicate the nozzle numbers. For example, a circle including “180” in the drawing indicates the position of the nozzle # 180.

  Next, a test pattern printing order will be described with reference to FIGS. 21 and 22.

  When the trailing edge of the paper S passes the transport roller, the head 41 is in the position of the head 41A in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the first dot formation process (pass 1). At this time, the head 41 forms five first band patterns using the nozzles on the upstream side (nozzle # 180 side) in the transport direction. Since five first band patterns are formed in one pass, the positions of these first band patterns in the transport direction are the same. In this pass 1, the head 41 uses the nozzle on the downstream side (nozzle # 1 side) in the transport direction, and the number (for example, “number = 1”, etc.) given to the correction pattern is also applied to the paper S. Form.

  Next, the controller 60 causes the transport unit 20 to transport the paper four times intermittently with a target transport amount of about 1/4 inch (176/720 inch in this embodiment). The target carry amount at this time is substantially equal to the target carry amount for printing in accordance with the purpose of use of the printer (printing performed by the user after printing the test pattern). If the target transport amount at the time of printing according to the purpose of use of the printer is 1/8 inch, after pass 1, the target transport amount is about 1/8 inch (for example, 176/1440 inch). Is intermittently conveyed 8 times.

  Note that during the intermittent conveyance described above, the paper S is actually conveyed in a state including a conveyance error. Then, after the intermittent conveyance, the paper S is in a state where the conveyance errors of the four conveyances are accumulated. The test pattern of the present embodiment is used to obtain an optimum correction amount for the transport error accumulated during intermittent transport (transport performed from pass 1 to pass 2).

  After intermittent conveyance, the head 41 is in the position of the head 41E in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the second dot formation process (pass 2). At this time, the head 41 uses the nozzle # 5 and a nozzle (nozzle # 6, etc.) upstream of the nozzle # 5 in the transport direction to give a correction pattern P3 (five corrections) to which “number = 3” is assigned. The second band pattern of the middle correction pattern) is formed. Thereby, the correction pattern P3 to which “number = 3” is attached is completed.

  Next, the controller 60 causes the transport unit 20 to transport the paper S with a target transport amount of 3/720 inch. However, since the paper conveyance amount at this time is small, no conveyance error occurs when the conveyance unit 20 conveys the paper. In other words, the paper is being transported at a transport amount of 3/720 inch which is the same as the target transport amount. As a result, the head 41 is in the position of the head 41F in the drawing with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the third dot formation process (pass 3). At this time, the head 41 uses the nozzle # 4 and the nozzles upstream of the nozzle # 4 in the transport direction (nozzle # 5, etc.), and the correction pattern P4 (five corrections) to which “number = 4” is assigned. The second band pattern of the second correction pattern from the right among the patterns for use) is formed. Thereby, the correction pattern P4 to which “No. = 4” is attached is completed.

  Next, the controller 60 causes the transport unit 20 to transport the paper S with a target transport amount of 3/720 inch. However, since the paper conveyance amount at this time is small, no conveyance error occurs when the conveyance unit 20 conveys the paper. In other words, the paper is being transported at a transport amount of 3/720 inch which is the same as the target transport amount. As a result, the head 41 is in the position of the head 41G in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the fourth dot formation process (pass 4). First, the head 41 uses a nozzle # 4 and a nozzle (nozzle # 5, etc.) upstream in the transport direction from the nozzle # 4, and a correction pattern P1 (five correction patterns) to which “number = 1” is assigned. The second band pattern of the leftmost correction pattern among the patterns) is formed. Thereby, the correction pattern P1 to which “number = 1” is attached is completed. Further, the head 41 uses the nozzle # 3 and the nozzle (nozzle # 4, etc.) upstream in the transport direction from the nozzle # 3, and the correction pattern P5 (five correction patterns) to which “number = 5” is assigned. The second band pattern of the rightmost correction pattern among the patterns is formed. Thereby, the correction pattern P5 to which “number = 5” is attached is completed. That is, in the dot formation process in pass 4, the controller 60 makes the head 41 form the second band pattern of two correction patterns at different locations in the transport direction by changing the nozzles that eject ink.

  Next, the controller 60 causes the transport unit 20 to transport the paper S with a target transport amount of 3/720 inch. However, since the paper conveyance amount at this time is small, no conveyance error occurs when the conveyance unit 20 conveys the paper. In other words, the paper is being transported at a transport amount of 3/720 inch which is the same as the target transport amount. As a result, the head 41 is in the position of the head 41H in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the fifth dot formation process (pass 5). At this time, the head 41 uses the nozzle # 3 and the nozzles upstream of the nozzle # 3 in the transport direction (nozzle # 4 and the like) and a correction pattern P4 (five corrections) to which “number = 2” is assigned. The second band pattern of the second correction pattern from the left among the patterns for use) is formed. Thereby, the correction pattern P2 to which “number = 2” is attached is completed.

  The test pattern formed in this way is a pattern in which a plurality of correction patterns are arranged in the order of correction amounts as described below.

<Regarding the correction amount corresponding to each correction pattern>
FIG. 23 is an explanatory diagram of the dot interval at the boundary between the first band pattern and the second band pattern of each correction pattern when there is no conveyance error. The left side of the figure shows the relative position of the head in each pass. The black circle on the right side in the figure indicates the dots that make up each correction pattern. On the right side of the drawing, only one row of dots along the transport direction is shown for each correction pattern. However, in reality, a large number of such dot rows are arranged in the scanning direction, as shown in FIGS. 15 and 21. In this way, a correction pattern is formed (described later). The number in the black circle on the right side in the figure indicates the number of the nozzle that forms the dot.

  When there is no conveyance error, the most upstream dot (the dot formed by nozzle # 180 in pass 1) of the dots constituting the first band pattern of the correction pattern P3 and the most downstream side of the dots constituting the second band pattern The distance D3 between the dots (dots formed by the nozzle # 5 in pass 2) is equal to the nozzle distance (= 1/180 inch). Therefore, no striped pattern is generated at the boundary between the first band pattern and the second band pattern of the correction pattern P3.

  On the other hand, when there is no transport error, when there is no transport error, the dots on the most upstream side of the dots constituting the first band pattern of the correction pattern 2 (dots formed by the nozzle # 180 in pass 1) and the second band pattern The distance D2 between the dots constituting the dots and the dots on the most downstream side (dots formed by the nozzle # 3 in pass 5) is 1/720 inch wider than the nozzle interval (= 1/180 inch). For this reason, a white stripe pattern is generated at the boundary between the first band pattern and the second band pattern of the correction pattern P2. Similarly, the interval D1 of the correction pattern P1 is widened by 2/720 inch from the nozzle interval. Therefore, a thick white stripe pattern is generated at the boundary portion of the correction pattern P1.

  Further, when there is no transport error, when there is no transport error, the dots on the most upstream side of the dots constituting the first band pattern of the correction pattern 4 (dots formed by the nozzle # 180 in pass 1) and the second band pattern The distance D4 between the dots forming the most downstream dots (dots formed by the nozzle # 4 in pass 3) is narrower by 1/720 inch than the nozzle interval (= 1/180 inch). Therefore, a black striped pattern is generated at the boundary between the first band pattern and the second band pattern of the correction pattern P4. Similarly, the interval D5 of the correction pattern P5 is narrower by 2/720 inch than the nozzle interval. Therefore, a thick black striped pattern occurs at the boundary portion of the correction pattern P5.

  Thus, the interval between the first band pattern and the second band pattern of each correction pattern changes by 1/720 inch. If there is no conveyance error during four intermittent transfers from pass 1 to pass 2, no stripe pattern is generated in the correction pattern P3 to which “number = 3” is attached. The pattern for use is selected as the optimum pattern (see S103).

  FIG. 24 shows the dot interval at the boundary between the first band pattern and the second band pattern of each correction pattern when “-1/720 inch transport error” has occurred during four intermittent transports. It is explanatory drawing of. Here, “− / 720 inch conveyance error” means that when the paper is conveyed based on the target conveyance amount, the actual conveyance amount is smaller than the target conveyance amount by 1/720 inch. Since “−1/720 inch conveyance error” occurs in the intermittent conveyance four times, the relative position of the nozzles after pass 2 is 1/720 compared to the nozzle position of FIG. It is off by an inch.

  If a “− / 720 inch transport error” has occurred during four intermittent transports, the dots on the most upstream side of the dots constituting the first band pattern of the correction pattern P2 (nozzles in pass 1) The distance D2 between the dots formed by # 180 and the dots on the most downstream side of the dots forming the second band pattern (dots formed by nozzle # 3 in pass 5) is the nozzle distance (= 1/180 inch). Is equal to Therefore, no striped pattern is generated at the boundary between the first band pattern and the second band pattern of the correction pattern P2. In other words, if a “− / 720 inch conveyance error” has occurred during four intermittent conveyances, the correction pattern P2 assigned with “number = 2” is selected as the optimum pattern. (See S103).

  In other words, if the correction pattern P2 is an optimum pattern, it is detected that the conveyance error occurring during the four intermittent conveyances is “−1/720 inch”. As a result, if the correction pattern P2 is an optimal pattern, a conveyance error of “−1/2880 inch” may occur for each conveyance (a conveyance with a target conveyance amount of about ¼ inch). Detected.

  Therefore, when the correction pattern P2 is selected as the optimum pattern, the correction amount 2C (= 2/5760 inch) is added to the target conveyance amount of about 1/4 inch, and the paper is based on the corrected target conveyance amount. If S is transported (if the counter of S041 is set based on the corrected target transport amount), the actual paper transport amount becomes the target transport amount. That is, the correction pattern P2 corresponds to the correction amount 2C.

  Similarly, the correction pattern P1 corresponds to the correction amount 4C, the correction pattern P3 corresponds to the correction amount 0, the correction pattern P4 corresponds to the correction amount −2C, and the correction pattern P5 corresponds to the correction amount −4C. It corresponds.

  According to the present embodiment, the five first band patterns of the five correction patterns are respectively formed at the same position with respect to the transport direction by one dot formation process. The five second band patterns of the five correction patterns are formed at different positions with respect to the transport direction. As a result, correction patterns having different intervals between the first band pattern and the second band pattern are formed along the scanning direction. In the test pattern of the reference example, since the correction pattern is arranged along the conveyance direction, a wide print area is necessary. On the other hand, in the test pattern of the present embodiment, since the correction patterns are arranged along the scanning direction, a large number of correction patterns can be formed in a print region having a narrow length L in the transport direction.

  In addition, according to the present embodiment, after forming the second band pattern of a certain correction pattern (for example, the correction pattern P3 with “number = 3”), the paper is fed at 3/720 inch by the transport unit. The second band pattern of the other correction pattern (for example, the correction pattern P4 to which “number = 4” is attached) is formed. As a result, the transport amount performed between the formation of the first band pattern of a certain correction pattern and the formation of the second band pattern, and the formation of the second band pattern from the formation of the first band pattern of another correction pattern. The amount of conveyance performed until this time is different. Thereby, the interval between the first band pattern and the second band pattern is different for each correction pattern. That is, the correction amount corresponding to each correction pattern is different. According to the present embodiment, a large number of correction patterns corresponding to different correction amounts can be formed in a narrow print region.

  Further, according to the present embodiment, nozzles (nozzles upstream from the nozzle # 4) that form the second band pattern of the correction pattern P1 to which “number = 1” is assigned, and “number = 5” are assigned. The nozzles forming the second band pattern of the correction pattern P5 (nozzles upstream from the nozzle # 3) are different. Since the positions in the transport direction of the nozzles used when forming each correction pattern are different, the positions in the transport direction of the second patterns to be formed are different. Thereby, the 2nd pattern of a position different in a conveyance direction can be formed in one pass. Further, according to the present embodiment, for example, nozzles (nozzles upstream from nozzle # 5) that form the second band pattern of the correction pattern P3 to which “number = 3” is attached, and “number = 4” The nozzles (nozzles upstream from nozzle # 4) that form the second band pattern of the correction pattern P4 to be attached are different. By using different nozzles and carrying 3/720 inch, the interval between the first band pattern and the second band pattern of each correction pattern can be reduced to 1/720 inch. Since the transport unit transports the paper using a motor, gears, or the like, it is difficult to accurately transport the paper with a short transport amount (for example, 1/720 inch). However, in this embodiment, the nozzles used are different. In addition, by adding paper conveyance, different correction patterns can be formed in order at intervals of 1/720 inch.

  Further, according to the present embodiment, 180 nozzles arranged in the transport direction are moved in the scanning direction. Thus, a band pattern composed of dots arranged along the transport direction and the scanning direction can be formed on the paper by intermittently ejecting ink while the plurality of nozzles are moving.

  Further, according to the present embodiment, the length in the transport direction of the printing area where the five correction patterns are formed is L (about 3.5 cm), and this length L is the width of the head (the most upstream nozzle). The length from a certain nozzle # 180 to the nozzle # 1, which is the most downstream nozzle, is shorter than twice an inch (= 2.54 cm). In the test pattern of the reference example, since the correction pattern is arranged along the conveyance direction, only one correction pattern can be formed in the printing region having a length L in the conveyance direction. However, since the test pattern is for selecting an optimum pattern from a plurality of correction patterns, it is necessary to form a plurality of correction patterns in the test pattern. According to the present embodiment, many correction patterns can be formed even in such a narrow print region.

  Further, according to the present embodiment, the transport unit includes an upstream roller (transport roller) positioned upstream of the print area (area facing the head 31) and a downstream roller (transport roller) positioned downstream of the print area. Paper discharge roller). In this embodiment, when the paper is transported only by the downstream roller (when the rear end of the paper passes through the transport roller), the correction pattern is formed on the paper. The conveyance state by two rollers and the conveyance state by one roller are different conveyance states. Therefore, if the correction amount according to the conveyance state by the two rollers is applied to the correction amount according to the conveyance state by the one roller, the image quality may be deteriorated. On the other hand, the printing area in the conveyance state by one roller is narrow. According to this embodiment, many correction patterns can be formed in a narrow print region where a medium is conveyed by one roller.

  In the present embodiment, the correction amount corresponding to the normal conveyance state (conveyance state using two rollers (upstream roller and downstream roller)) is the conveyance amount only by the downstream roller (the trailing edge of the paper is This is different from the transport amount according to the transport state when passing the transport roller. This is because if the correction amount according to the conveyance state by the two rollers is applied to the correction amount according to the conveyance state by the one roller, the image quality may be deteriorated. In the present embodiment, the memory 63 stores not only information on the correction amount according to the normal conveyance state but also information on the correction amount applied after the trailing edge of the paper passes the conveyance roller. If the paper detection sensor 53 detects the trailing edge of the paper and then transports the paper by a predetermined transport amount, the trailing edge of the paper passes through the transport roller, so the controller 60 causes the trailing edge of the paper to pass through the transport roller. After that, when the target transport amount is corrected, the correction amount is switched from the correction amount according to the normal transport state to the correction amount according to the transport state using only the discharge rollers.

  Further, in the present embodiment, the first band pattern of a certain correction pattern (for example, the correction pattern P3 to which “number = 3” is attached) is assigned another correction pattern (for example, “number = 4”). The first band pattern of the correction pattern P4 and the like) is formed apart from the scanning direction. Thereby, a plurality of correction patterns are visually recognized separately. Therefore, it is convenient when the user selects an optimal correction pattern from a plurality of correction patterns.

  In this embodiment, for example, the transport unit performs transport four times between the formation of the first band pattern and the formation of the second band pattern of the correction pattern P3 to which “number = 3” is attached. Yes. As a result, the interval between the first band pattern and the second band pattern reflects the conveyance error accumulated during four conveyances (four times as large as one conveyance error). That is, if an optimum correction pattern is selected from a plurality of correction patterns, the accumulated transport error can be detected.

  Further, according to the present embodiment, in order to identify each correction pattern, a code such as “number = 1” is attached to each correction pattern. Therefore, it is convenient when the user selects an optimal correction pattern from a plurality of correction patterns. When printing a test pattern for correcting the carry amount, a number corresponding to the correction pattern is displayed on the display device connected to the computer. An optimum pattern can be selected in correspondence with the displayed number.

  Further, according to the present embodiment, a code such as “number = 1” for identifying the correction pattern is formed together when the first band pattern is formed. For example, when the nozzles on the upstream side in the transport direction form the first band pattern of the correction pattern P1, the nozzles on the downstream side in the transport direction form “number = 1”. As a result, a large number of correction patterns can be formed in a narrow print region, and a code for identifying the correction pattern can be formed.

  Further, according to the present embodiment, a code such as “number = 1” for identifying the correction pattern is formed adjacent to the correction pattern in the transport direction. When a code such as “number = 1” is adjacent to the correction pattern in the scanning direction as in the test pattern of the reference example, the correction pattern and the correction pattern are arranged even if the correction patterns are arranged in the scanning direction. And a large number of correction patterns cannot be arranged in the scanning direction. On the other hand, according to the present embodiment, since the intervals between the plurality of correction patterns can be shortened, a large number of correction patterns can be formed in a narrow print region.

=== Configuration of Band Pattern ===
The correction pattern band patterns (first band pattern and second band pattern) are composed of countless dots arranged along the transport direction and the scanning direction. Hereinafter, the dots constituting the band pattern will be described.

  FIG. 25A to FIG. 25D are examples of dots constituting a band pattern. As shown in the figure, the band patterns are arranged along the transport direction and the scanning direction. The dot interval in the carrying direction is equal to the nozzle interval and is 1/180 inch. However, the interval between the dots in the scanning direction may be 1/180 inch or may be another interval.

  In the band pattern of FIG. 25A, adjacent dots are not in contact. In the band pattern of FIG. 25B, adjacent dots are in contact. Thus, the band pattern of the above-mentioned test pattern may be in contact with adjacent dots or may not be in contact.

  The band pattern in FIG. 25C is composed of dots of different sizes (large dots, medium dots, small dots). In the band pattern of the above test pattern, dots having different sizes may be mixed. Even if dots of different sizes are mixed, it is possible to form a uniform density pattern as the entire band pattern. The optimal correction pattern for test patterns consisting of only large dots may differ from the optimal correction pattern for test patterns consisting of only small dots due to the effects of ink drying and ink bleeding. Therefore, if an optimal correction pattern is selected using a test pattern composed of dots of different sizes, the average correction amount can be specified.

  The band pattern in FIG. 25D is composed of dots of different colors (black, cyan, magenta, yellow). “K” in the figure indicates a black dot composed of black ink. “C” in the figure indicates a cyan dot composed of cyan ink. “M” in the drawing indicates magenta dots formed by magenta ink. “Y” in the figure indicates a yellow dot composed of yellow ink. The optimum correction pattern of the test pattern composed only of each color may differ depending on the mounting error of each nozzle group, dimensional tolerance, etc., so use a test pattern composed of different color dots. If an optimum correction pattern is selected, an average correction amount can be specified.

  The band pattern of the above test pattern may be any of the above band patterns. Moreover, the band pattern which combined the concept of said band pattern may be sufficient.

=== Another Embodiment ===
Next, an embodiment different from the above-described embodiment will be described below. However, the same description as the above-described embodiment is omitted for simplification.

  FIG. 26 is an explanatory diagram showing an arrangement of nozzles according to another embodiment. 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 a plurality of nozzles (720 in this embodiment) which are ejection openings for ejecting ink of each color. In this embodiment, the nozzle pitch is different from that in the above-described embodiment. In this embodiment, the nozzle pitch is 720 dpi (1/720 inch).

  Next, a test pattern printing method according to the present embodiment will be described with reference to FIGS. Each operation described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  When the trailing edge of the paper S passes the transport roller, the head 41 is in the position of the head 41A in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the first dot formation process (pass 1). At this time, the head 41 forms five first band patterns using the nozzles on the upstream side (nozzle # 180 side) in the transport direction. However, the nozzles used for forming the first band pattern are nozzles having a number that is a multiple of four. As a result, the dot spacing in the transport direction of the dots constituting the first band pattern becomes 1/180 inch. The nozzles used for forming the five first band patterns are the same. Thereby, the positions in the transport direction of these first band patterns are the same.

  Next, the controller 60 causes the transport unit 20 to transport the paper four times intermittently with a target transport amount of 1/4 inch (180/720 inch in this embodiment). The target carry amount at this time is substantially equal to the target carry amount for printing in accordance with the purpose of use of the printer (printing performed by the user after printing the test pattern). If the target transport amount for printing in accordance with the purpose of use of the printer is 1 inch, after pass 1, the paper is transported intermittently once with the target transport amount of 1 inch.

  Note that during the above intermittent conveyance (conveyance performed from pass 1 to pass 2), the paper S is actually conveyed in a state including a conveyance error. Then, after the intermittent conveyance, the paper S is in a state where the conveyance errors of the four conveyances are accumulated. The test pattern of the present embodiment is used to obtain an optimum correction amount for the transport error accumulated during intermittent transport (transport performed from pass 1 to pass 2).

  After intermittent conveyance, the head 41 is in the position of the head 41E in the figure with respect to the paper S. Then, the controller 60 moves the carriage 31 in the scanning direction and ejects ink from the head 41 to perform the second dot formation process (pass 2).

  Here, in this embodiment, the controller 60 makes the head 41 form second band patterns of a plurality of correction patterns at different locations in the transport direction by changing the nozzles that eject ink. Hereinafter, this point will be described in detail. In the following description, it is assumed that the head 41 moves from left to right in the drawing.

First, the head 41 uses the nozzle # 6 and the nozzle # 4N + 2 upstream of the nozzle # 6 (for example, nozzle # 10, etc., where N is an integer) for correction with “number = 1”. A second band pattern of the pattern P1 is formed. Thereby, the correction pattern P1 to which “number = 1” is attached is completed.
Subsequently, while the second dot formation process (pass 2) is being performed, the head 41 uses the nozzle # 5 and the nozzle # 4N + 1 (for example, the nozzle # 9) on the upstream side of the nozzle # 5. Thus, the second band pattern of the correction pattern P2 to which “number = 2” is attached is formed. Thereby, the correction pattern P2 to which “number = 2” is attached is completed.

Further, during the second dot formation process (pass 2), the head 41 uses the nozzle # 4 and the nozzle # 4N (for example, the nozzle # 8) on the upstream side of the nozzle # 4. , The second band pattern of the correction pattern P3 to which “number = 3” is attached is formed. Thereby, the correction pattern P3 to which “number = 3” is attached is completed.
During the second dot formation process (pass 2), the head 41 performs nozzle # 3 and nozzle # 4N-1 (for example, nozzle # 7) on the upstream side of nozzle # 3. The second band pattern of the correction pattern P4 to which “No. = 4” is attached is formed. Thereby, the correction pattern P4 to which “No. = 4” is attached is completed.

Finally, while the second dot formation process (pass 2) is being performed, the head 41 performs nozzle # 2 and nozzle # 4N-2 (for example, nozzle 6) on the upstream side of nozzle # 2. The second band pattern of the correction pattern P5 to which “No. = 5” is attached is formed. Thereby, the correction pattern P5 to which “number = 5” is attached is completed.
The test pattern formed in this way is a pattern in which a plurality of correction patterns are arranged in the order of correction amounts as described below.

  The nozzles (nozzles # 6, 10, 14,...) That form the second band pattern of the correction pattern P1 to which “number = 1” is assigned are the second of the correction pattern P2 to which “number = 2” is assigned. It is located upstream of the nozzles (nozzles # 5, 9, 13,...) That form the band pattern by one nozzle. On the other hand, the nozzle pitch is 1/720 inch. Therefore, the second band pattern of the correction pattern P1 to which “number = 1” is attached is upstream of the second band pattern of the correction pattern P2 to which “number = 2” is attached by 1/720 inch. Formed. As a result, the interval D1 between the correction patterns P1 is wider by 1/720 inch than the interval D2 between the correction patterns P2.

  Thus, the interval between the first band pattern and the second band pattern of each correction pattern changes by 1/720 inch. If there is no conveyance error in the four intermittent conveyances from pass 1 to pass 2, the interval D3 of the correction pattern P3 with “number = 3” is 1/180 inch. Therefore, no stripe pattern is generated in the correction pattern P3, so that the correction pattern P3 is selected as an optimum pattern (see S103).

  If a “− / 720 inch conveyance error” occurs during four intermittent conveyances, the interval D2 of the correction pattern P2 with “number = 2” is 1/180 inch. Therefore, since no stripe pattern is generated in the correction pattern P2, the correction pattern P2 is selected as an optimum pattern (see S103).

  In other words, if the correction pattern P2 is an optimum pattern, it is detected that the conveyance error occurring during the four intermittent conveyances is “−1/720 inch”. As a result, if the correction pattern P2 is an optimum pattern, it is detected that a conveyance error of “−1/2880 inch” occurs for each conveyance (a conveyance with a target conveyance amount of ¼ inch). Is done.

Therefore, when the correction pattern P2 is selected as the optimum pattern, the correction amount 2C (= 2/5760 inch) is added to the target conveyance amount of about 1/4 inch, and the paper is based on the corrected target conveyance amount. If S is transported (if the counter of S041 is set based on the corrected target transport amount), the actual paper transport amount becomes the target transport amount. That is, the correction pattern P2 corresponds to the correction amount 2C.
Similarly, the correction pattern P1 corresponds to the correction amount 4C, the correction pattern P3 corresponds to the correction amount 0, the correction pattern P4 corresponds to the correction amount −2C, and the correction pattern P5 corresponds to the correction amount −4C. It corresponds.

  Even in the present embodiment, since the correction patterns are arranged along the scanning direction, a large number of correction patterns can be formed in a print region having a length L in the transport direction, which is the above-described embodiment. The same effect can be obtained.

  Further, according to the present embodiment, the nozzles that form the second band pattern of a certain correction pattern (for example, the correction pattern P1 to which “number = 1” is assigned) and other correction patterns (for example, “ The nozzles forming the second band pattern of the correction pattern P2) to which “number = 2” is attached are different. Since the positions in the transport direction of the nozzles used when forming each correction pattern are different, the positions in the transport direction of the second patterns to be formed are different. Thereby, the 2nd pattern of a position different in a conveyance direction can be formed in one pass.

=== Other Embodiments ===
The above-described embodiment is mainly described for a printer. Among them, a printing apparatus, a recording apparatus, a liquid ejection apparatus, a printing method, a recording method, a liquid ejection method, a printing system, a recording system, and a computer system are included. Needless to say, the disclosure includes a program, a storage medium storing the program, a display screen, a screen display method, a printed material manufacturing method, and the like.

  Moreover, although the printer etc. as one embodiment were demonstrated, said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this 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 first band pattern and the second band pattern>
According to the above-described embodiment, the first band patterns of the plurality of correction patterns are formed at the same position with respect to the transport direction, and the second band patterns of the plurality of correction patterns are respectively different positions with respect to the transport direction. Was formed. However, the first band pattern and the second band pattern may be reversed. That is, the second band patterns of the plurality of correction patterns may be formed at the same position with respect to the transport direction, and the first band patterns of the plurality of correction patterns may be formed at different positions with respect to the transport direction. . Even if it does in this way, the effect similar to the above-mentioned embodiment can be acquired.

<About the first band pattern>
According to the above-described embodiment, the first band pattern of a certain correction pattern (for example, the correction pattern P3 to which “number = 3” is attached) has another correction pattern (for example, “number = 2”). It was formed on the paper apart from the first band pattern of the correction pattern P2). However, the first band patterns of the respective correction patterns need not be formed separately.

  FIG. 29 is an explanatory diagram of a first band pattern according to another embodiment. In the present embodiment, the first band pattern of five correction patterns is integrally formed during pass 1. In other words, in the present embodiment, the first band pattern of a certain correction pattern (for example, the correction pattern P3 to which “number = 3” is attached) is assigned another correction pattern (for example, “number = 2”). The correction pattern P2) is formed integrally with the first band pattern. Even when the first band pattern is formed in this way, the same effect as that of the above-described embodiment can be obtained. However, as in the above-described embodiment, forming the first band patterns apart from each other is more convenient when selecting an optimum pattern.

<About rear end>
According to the above-described embodiment, the test pattern is formed on the rear end side of the paper after the rear end of the paper has passed the transport roller. However, the position where the test pattern is printed is not limited to this.

  For example, a test pattern may be formed on the leading end side of the paper. Before the leading edge of the paper transported to the transport roller passes through the paper discharge roller, the paper is not transported by both the transport roller and the paper discharge roller, but is transported only by the transport roller. This is because different transport states occur. The printing area being conveyed only by the conveying roller is a narrow area because the length in the conveying direction is short, as in the state where the sheet is conveyed only by the paper discharge roller. Therefore, as in the above-described embodiment, a large number of correction patterns can be formed by forming a plurality of correction patterns in a narrow area on the leading end side of the paper along the scanning direction.

  In the present embodiment, the memory 63 stores not only information on the correction amount according to the normal conveyance state but also information on the correction amount applied before the leading edge of the paper passes the paper discharge roller. After the paper detection sensor 53 detects the leading edge of the paper, if the paper is transported by a predetermined transport amount, the leading edge of the paper passes through the paper discharge roller. Therefore, the controller 60 passes the paper leading edge through the paper discharge roller. Thereafter, when the target transport amount is corrected, the correction amount is switched from the correction amount according to the transport state using only the transport roller to the correction amount according to the normal transport state.

  Further, a similar test pattern may be formed in a printing region in a normal conveyance state (a state where paper is conveyed by two rollers, a conveyance roller and a discharge roller). Even in such a case, an effect of printing a large number of correction patterns in a narrow print region can be obtained.

<Regarding correction pattern placement>
According to the above-described embodiment, the first band patterns of the plurality of correction patterns are each formed at the same position with respect to the transport direction. However, they need not be formed at exactly the same position. For example, the first band pattern of each correction pattern may be formed at a position shifted in the transport direction. In short, the plurality of correction patterns are arranged in a direction (scanning direction) intersecting the transport direction, so that the plurality of correction patterns have a narrow print area (for example, the length L in the transport direction as shown in FIG. 20). In the printing area).

<About printing devices>
According to the above-described embodiment, the printing apparatus is an ink jet printer that ejects ink from nozzles. However, the printing apparatus is not limited to an ink jet printer. In short, any printing apparatus that includes a transport unit that transports a medium such as paper and sets a correction amount for offsetting a transport error of the transport unit may be used. And, if a test pattern for correcting the target transport amount of the transport unit of such a printing apparatus is formed on paper in the same manner as in the previous embodiment, many correction patterns can be printed on a narrow area of the paper, The same effects as those of the above-described embodiment can be obtained.

<About ink>
Since the above-described embodiment is an embodiment of a printer, dye ink or pigment ink is ejected from the nozzle. However, the liquid ejected from the nozzle is not limited to such ink. For example, liquids (including water) including metal materials, organic materials (especially polymer materials), magnetic materials, conductive materials, wiring materials, film-forming materials, electronic inks, processing liquids, gene solutions, etc. are ejected from nozzles. May be. If such a liquid is directly discharged toward the object, material saving, process saving, and cost reduction can be achieved.

<About nozzle>
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.

It is explanatory drawing of the whole structure of a printing system. 1 is a block diagram of an overall configuration of a printer. 1 is a schematic diagram of an overall configuration of a printer. 1 is a cross-sectional view of the overall configuration of a printer. It is a flowchart of the process at the time of printing. It is explanatory drawing which shows the arrangement | sequence of a nozzle. It is explanatory drawing of the drive circuit of a head unit. It is a timing chart for explanation of each signal. It is explanatory drawing of a structure of a conveyance unit. It is explanatory drawing of a structure of a rotary encoder. FIG. 11A is a timing chart of the waveform of the output signal during forward rotation. FIG. 11B is a timing chart of the waveform of the output signal at the time of inversion. It is a flowchart of a conveyance process. It is a flowchart for demonstrating the determination procedure of a correction amount. It is an instruction screen for printing a test pattern. It is an example of the test pattern for conveyance amount correction | amendment. This is a screen for selecting an optimum pattern. It is a flowchart when forming an image on paper. It is explanatory drawing of the printing method of the test pattern in a reference example. FIG. 19A is an explanatory diagram of a normal transport process. FIG. 19B is an explanatory diagram of the transport process after the trailing edge of the paper has passed the transport roller. FIG. 6 is an explanatory diagram of a positional relationship between the paper and the head when the rear end of the paper passes through a conveyance roller. It is explanatory drawing of the printing method of the test pattern of this embodiment. It is explanatory drawing of the positional relationship of the nozzle and paper in the printing method of the test pattern of this embodiment. It is explanatory drawing between the 1st, 2nd band patterns when there is no conveyance error. It is explanatory drawing between the 1st, 2nd band patterns in case there exists a conveyance error. FIG. 25A to FIG. 25D are examples of dots constituting a band pattern. It is explanatory drawing which shows the arrangement | sequence of the nozzle of another embodiment. It is explanatory drawing of the printing method of the test pattern of another embodiment. It is explanatory drawing of the positional relationship of the nozzle and paper in the printing method of the test pattern of another embodiment. It is explanatory drawing of the 1st band pattern of other embodiment. FIG. 30A is an explanatory diagram of the discharge operation and the transport operation. FIG. 30B is an explanatory diagram of image quality degradation due to a transport error.

Explanation of symbols

1 printer,
20 transport unit, 21 paper feed roller, 22 transport motor (PF motor),
23 transport roller, 24 platen, 25 discharge roller,
30 Carriage unit, 31 Carriage,
32 Carriage motor (CR motor),
40 head units, 41 heads,
50 sensors, 51 linear encoders, 52 rotary encoders,
521 scale, 522 detector,
53 Paper detection sensor, 54 Optical sensor,
60 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit 644A original drive signal generating unit, 644B drive signal shaping unit,
100 printing system 110 computer,
120 display device,
130 input device, 130A keyboard, 130B mouse,
140 recording / reproducing apparatus, 140A flexible disk drive apparatus, 140B CD-ROM drive apparatus

Claims (17)

A plurality of nozzles that eject ink while moving in the moving direction;
A transport unit that transports the medium in the transport direction,
A pattern before conveyance formed by the plurality of nozzles before conveyance by the conveyance unit, and formed by the plurality of nozzles after conveyance by the conveyance unit and formed adjacent to the pattern before conveyance and the conveyance direction. A printing apparatus for printing a plurality of correction patterns on a medium having a post-conveying pattern,
(A) The plurality of pre-transport patterns in the plurality of correction patterns are formed by ejecting ink while the plurality of nozzles move once in the movement direction,
The ejection of ink while the plurality of nozzles move in the movement direction and the conveyance unit conveying the medium are alternately repeated a plurality of times, so that one post-conveying pattern is one time. By forming the plurality of post-conveying patterns in the plurality of correction patterns while being formed during the movement of the nozzle ,
A plurality of the correction patterns are arranged in a direction intersecting the transport direction and formed on the medium.
(B) Each time the medium is transported in the transport direction with a transport amount shorter than the nozzle pitch of the plurality of nozzles, and the post-transport pattern every time the medium is transported in the transport direction with the short transport amount. By changing the nozzles used for forming the plurality of correction patterns, the intervals between the pre-carrying pattern and the post-carrying pattern are stepwise different at intervals shorter than the carry amount. A printing apparatus characterized by that. The printing apparatus according to claim 1,
A printing apparatus, further comprising a carriage that moves a plurality of nozzles arranged along the transport direction. The printing apparatus according to claim 2,
One of the pattern before conveyance and the pattern after conveyance of the plurality of correction patterns is formed at the same position with respect to the conveyance direction, respectively.
The other patterns are formed at different positions with respect to the transport direction,
The printing apparatus is characterized in that a nozzle that forms the other pattern of a certain correction pattern is different from a nozzle that forms the other pattern of another correction pattern. The printing apparatus according to claim 2 or 3,
The nozzle can form dots of a plurality of sizes on the medium,
At least one of the pre-carrying pattern and the post-carrying pattern is configured by the plurality of sized dots. The printing apparatus according to any one of claims 2 to 4,
At least one of the pre-carrying pattern and the post-carrying pattern is composed of a plurality of dots of different colors. The printing apparatus according to any one of claims 2 to 5,
The length of the area in which the plurality of correction patterns are formed in the transport direction is shorter than twice the length from the most upstream nozzle to the most downstream nozzle among the plurality of nozzles. apparatus. The printing apparatus according to any one of claims 1 to 6,
The transport unit includes an upstream roller located on the upstream side of the printing area, and a downstream roller located on the downstream side of the printing area,
The printing apparatus, wherein the correction pattern is formed on the medium when the medium is conveyed by one of the upstream roller and the downstream roller. The printing apparatus according to claim 7, wherein
The correction amount for the transport amount when transporting the medium using the upstream roller and the downstream roller is different from the correction amount for the transport amount when transporting the medium using the one roller. Characteristic printing device. The printing apparatus according to claim 7 or 8,
The printing apparatus according to claim 1, wherein a shape of the downstream roller is different from a shape of the upstream roller. The printing apparatus according to any one of claims 7 to 9,
The shape of the driven roller facing the downstream roller is different from the shape of the driven roller facing the upstream roller. It is a printing apparatus in any one of Claims 7-10, Comprising:
The printing apparatus, wherein a conveyance speed of the downstream roller is different from a conveyance speed of the upstream roller. The printing apparatus according to any one of claims 1 to 6,
The transport unit includes an upstream roller located on the upstream side of the printing area, and a downstream roller located on the downstream side of the printing area,
The printing apparatus, wherein the correction pattern is formed on the medium when the medium is conveyed by the upstream roller and the downstream roller. The printing apparatus according to any one of claims 1 to 12,
The printing apparatus, wherein the transport unit transports a plurality of times between the formation of the pre-transport pattern and the formation of the post-transport pattern. The printing apparatus according to claim 1,
A printing apparatus, wherein a code for identifying a correction pattern is attached to each correction pattern. The printing apparatus according to claim 14,
The printing apparatus is characterized in that the code is formed together when the pre-transport pattern is formed. The printing apparatus according to claim 14 or 15,
The printing apparatus according to claim 1, wherein the code is formed adjacent to the conveyance direction of the correction pattern. A test pattern manufacturing method for printing a correction pattern having a pattern before conveyance and a pattern after conveyance on a plurality of media,
Forming a pre-transport pattern with a plurality of nozzles that eject ink while moving in the moving direction before transporting the medium;
Conveying the medium;
Forming a pattern after conveyance by the plurality of nozzles adjacent to the conveyance direction after the medium is conveyed, and the conveyance direction;
(A) The plurality of pre-transport patterns in the plurality of correction patterns are formed by ejecting ink while the plurality of nozzles move once in the movement direction,
The ejection of ink while the plurality of nozzles move in the movement direction and the conveyance unit conveying the medium are alternately repeated a plurality of times, so that one post-conveying pattern is one time. By forming the plurality of post-conveying patterns in the plurality of correction patterns while being formed during the movement of the nozzle ,
A plurality of the correction patterns are arranged in a direction intersecting the transport direction and formed on the medium.
(B) Each time the medium is transported in the transport direction with a transport amount shorter than the nozzle pitch of the plurality of nozzles, and the post-transport pattern every time the medium is transported in the transport direction with the short transport amount. By changing the nozzles used for forming the plurality of correction patterns, the intervals between the pre-carrying pattern and the post-carrying pattern are stepwise different at intervals shorter than the carry amount. The test pattern manufacturing method characterized by the above-mentioned.

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