JP2006069099A - Printing device, computer program, printing system and method for adjusting relative positions of dots - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set an adjustment value to adjust the relative positions of dots by restraining an influence of the undulation of a printing medium. <P>SOLUTION: By varying the relative positions of a first dot formed in an ink discharge section and a second dot formed at a time different from the first dot in a prescribed direction, the positions of peak sub patterns in which density peaks in the prescribed direction which are owned the two adjustment printing patterns having a plurality of sub patterns arranged in a manner that makes the density sequentially change along the prescribed direction are made different, the two adjustment printing patterns are printed in a manner that makes them intersect the prescribed direction, and the relative positions are adjusted on the basis of the output of a light receiving section at the time when a change in the density of the two adjustment printing patterns in the prescribed direction is detected by an optical sensor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus, a computer program, a printing system, and a method for adjusting the relative positions of dots.

  While reciprocatingly moving a print head in which a large number of nozzles serving as an ink discharge section are reciprocated, ink droplets are discharged from each nozzle to form dots on a print medium such as printing paper, thereby printing an image, text, or the like. An ink jet printer is known as a printing apparatus.

  When forming dots at a predetermined target position, the relative positions of the dots formed in the forward path and the backward path in the moving direction of the print head, or the dots formed in the forward path and the backward path moved at different timings. If they are different, the image quality deteriorates. For this reason, it is necessary to adjust the relative positions of the dots formed during each movement of the print head. For this reason, a plurality of adjustment values can be set in the printer, and an appropriate adjustment value is selected by the user or the like and set in the printer (see Patent Document 1).

For example, when setting an adjustment value for adjusting the relative position of dots formed in the forward path and the backward path of the print head, first, the relative position of dots formed in the forward path and the backward path is set to a predetermined amount. By making them different one by one, an adjustment print pattern is printed in which a plurality of sub-patterns formed so as to have different densities are arranged so that the densities sequentially change in a predetermined direction. Then, the density of the adjustment print pattern is detected along the predetermined direction by an optical sensor or the like, and an adjustment value that is an appropriate adjustment amount is set based on the detected result.
JP 2000-296609 A

  However, a printing paper as a printing medium may swell, so-called cockling, due to ejected ink or external force due to a rib or the like provided in the transport path. In particular, the cockling caused by the ejected ink may have different bending rates depending on the amount of ejected ink. For this reason, when the adjustment print pattern is printed on the printing paper, the sub-patterns having different densities of the adjustment print pattern have different amounts of ink. There is a risk of cockling.

  For this reason, since the print paper on which the adjustment print pattern is printed has cockling, when the density of the adjustment print pattern is detected by the optical sensor, printing is performed with the optical sensor in each sub-pattern. The distance from the paper and the angle when the optical sensor and the printing paper face each other are different. For this reason, the density of the print pattern for adjustment cannot be accurately detected, and an incorrect adjustment value may be set based on an inaccurate output, and as a result, a good image may not be printed. There was a problem.

  The present invention has been made in view of the above problems, and an object thereof is to set an adjustment value for adjusting the relative position of dots while suppressing the influence of waviness of the print medium. A printing apparatus, a computer program, a printing system, and a method for adjusting a relative position of dots are provided.

  The main invention is (a) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on a medium, (b) a light emitting unit for emitting light, and outputting a signal based on the received light (C) a relative position in the predetermined direction between the first dot formed by the ink discharge unit and the second dot formed at a timing different from the first dot. By making them different, the two adjustment print patterns each having two adjustment print patterns having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction, and the density has a peak. Different positions of the peak sub-pattern in the predetermined direction, and the two adjustment print patterns are printed so as to be aligned in a direction intersecting the predetermined direction, A control unit that adjusts the relative position based on the output of the light receiving unit when the change in density of the two adjustment print patterns in the predetermined direction is detected by the optical sensor; This is a printing apparatus.

  Other features of the present invention will be clarified by the description of the present specification and the accompanying drawings.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

  (A) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on the medium; (b) a light emitting unit for emitting light; and a light receiving unit for outputting a signal based on the received light. (C) By making the relative positions in the predetermined direction different between the first dots formed at the ink discharge section and the second dots formed at timings different from the first dots. , A peak sub-pattern having a peak density, each of the two adjustment print patterns having two adjustment print patterns having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction. And the two adjustment print patterns are printed so that the two adjustment print patterns are aligned in a direction crossing the predetermined direction. A printing unit comprising: a control unit that adjusts the relative position based on an output of the light receiving unit when a change in density of the pattern in the predetermined direction is detected by the optical sensor; and (d). Device.

  According to such a printing apparatus, the two adjustment print patterns are formed by changing the positions in the predetermined direction of the peak sub-patterns included in the respective adjustment print patterns. Each adjustment print pattern can be printed at different parts. That is, among the sub-patterns included in each adjustment print pattern, sub-patterns in which the relative positions of the first dots and the second dots are substantially the same can be formed at different positions in a predetermined direction. For this reason, by using two adjustment print patterns formed on different parts of the print medium, it is possible to adjust more appropriately than when adjusting the relative positions of dots using one adjustment print pattern. is there. In particular, since the two adjustment print patterns are printed so as to be aligned in a direction crossing the predetermined direction, each adjustment print pattern has sub-patterns having different densities at substantially the same position in the predetermined direction of the medium. Will be formed. That is, since almost the same position in the predetermined direction of the medium has almost the same undulation, it is possible to acquire two pieces of information on which the undulation similarly affects the output of the light receiving unit. For this reason, it is possible to obtain information from which the influence of waviness and the like is eliminated from the two pieces of information, and it is possible to adjust the relative position more accurately using the information from which the influence of waviness and the like is eliminated.

In such a printing apparatus, the change in density of the two adjustment print patterns is detected in association with the position in the predetermined direction, and the output of the light receiving unit is detected in association with the same position in the predetermined direction. It is desirable to adjust the relative position based on the difference in density.
According to such a printing apparatus, since the densities of the two adjustment print patterns are detected in association with the positions in the predetermined direction, the same position in the predetermined direction, that is, the position where the undulation or the like affects almost the same. The concentration of can be easily obtained. Then, unnecessary information that similarly affects the two adjustment print patterns is obtained by obtaining a difference in output indicating the density associated with the same position in the predetermined direction, obtained from the two adjustment print patterns. It can be removed.

In such a printing apparatus, the first dot and the second dot have a plurality of adjustment values in which the relative position in the predetermined direction changes step by step by a predetermined amount, and the adjacent sub patterns are different from each other. It is desirable to be formed with a value.
According to such a printing apparatus, it is possible to print two different adjustment print patterns so that the density changes at a similar rate along a predetermined direction. For this reason, when adjusting the relative position using the density of the sub-pattern formed at the same position in the predetermined direction, it is easy to process the output of the optical sensor, and the adjustment value can be clearly obtained. .

  In such a printing apparatus, the two adjustment print patterns are such that the first dot and the second dot are theoretically formed at the same position in the predetermined direction, and the sub-pattern has a predetermined reference position in the predetermined direction. Position at which the density difference detected in association with the same position in the predetermined direction of the two adjustment print patterns is switched from positive to negative, or from negative to positive, arranged so as to be distributed to each other as the center It is desirable to adjust the relative position based on the distance from the reference position.

  In the sub-pattern in which the first dot and the second dot are theoretically formed at the same position in the predetermined direction, since the first dot and the second dot overlap, the area occupied by the dots formed per unit area becomes narrower. Therefore, the peak sub-pattern has the lowest density. The two adjustment print patterns are arranged so as to distribute the sub patterns having the lowest theoretical density of the respective adjustment print patterns around the reference position in a predetermined direction. For this reason, in a state where the adjustment print pattern is printed, when the first dot and the second dot overlap, that is, when adjustment is not necessary, the sub-pattern having the lowest theoretical density is They are arranged equidistant from the reference position. At this time, of the two adjustment print patterns, one of the adjustment print patterns has a theoretically lowest peak, and the other adjustment print pattern has a theoretically lowest peak. The density changes sequentially in the direction of. Here, when the densities of the two adjustment print patterns are detected by the optical sensor, for example, it is assumed that the lowest density is a “positive value” and the highest value is “0”. explain. At this time, when the difference between the density of one of the two sub-patterns formed at the same position in the predetermined direction and the density of the other sub-pattern is obtained, the calculated information is the adjustment print pattern. The maximum positive value and the negative maximum value are obtained at the position of the sub-pattern having the lowest density. In other words, the density difference between the two adjustment print patterns at the same position in the predetermined direction changes from a positive value to a negative value and from a positive value to a negative value between the peak sub-patterns of the two adjustment print patterns. The position where the value shifts to the value of is located in the middle of the peak sub-patterns of the two adjustment print patterns, that is, at the reference. For this reason, by obtaining the difference between the density detected in one adjustment print pattern and the density detected in the other adjustment print pattern at the same position in a predetermined direction, it is caused by undulation of the medium. It is possible to seek information excluding the influence.

  On the other hand, in a state where the adjustment print pattern is printed and the first dot and the second dot do not overlap, the sub-patterns having the lowest density of the two adjustment print patterns are both It is formed at a position shifted by substantially the same amount in a predetermined direction. For this reason, when the difference between the density detected by one adjustment pattern and the density detected by the other adjustment pattern is obtained at the same position in a predetermined direction, the value is changed from a positive value to a negative value. In other words, the position from the positive value to the negative value is shifted from the reference position. Therefore, by adjusting the relative position based on the shifted distance, it is possible to easily adjust the relative position with an appropriate adjustment value by eliminating the influence of the waviness of the medium.

In such a printing apparatus, the ink discharge portion can reciprocate, the first dot is formed by movement of the ink discharge portion in the forward direction, and the second dot is formed in the return direction of the ink discharge portion. It is desirable to form by movement.
According to such a printing apparatus, when the ink ejection unit is reciprocated, the first dot is formed by the movement in the forward direction, and the second dot is formed by the movement in the backward direction. Thus, it is possible to appropriately adjust the relative position shift between the first dot and the second dot. Therefore, it is possible to print a good image while reciprocating the ink discharge unit.

In such a printing apparatus, the ink ejection unit can reciprocate, the first dot is formed by movement in a specific direction in the forward or backward direction of the ink ejection unit, and the second dot is the first dot. It is good also as forming by the movement of the said specific direction performed at the timing different from 1 movement.
According to such a printing apparatus, when an image is printed by forming the first dot while moving the ink ejection unit in a predetermined direction and forming the second dot by moving in a specific direction at different timings, It is possible to appropriately adjust the relative position shift between the first dot and the second dot. For this reason, it is possible to print a good image while moving the ink discharge portion a plurality of times in a specific direction.

In such a printing apparatus, a plurality of the ink discharge portions are provided along a predetermined direction, and the first dot and the second dot are different from each other when the ink discharge portion moves once in the predetermined direction. It is good also as forming in an ink discharge part.
According to such a printing apparatus, when the ink ejecting portion moves once in a predetermined direction, the first dot and the second dot formed by different ink ejecting portions provided along the predetermined direction. The relative position can be adjusted. For example, when inks of different colors are ejected from ink ejection units provided in a predetermined direction, it is possible to print a color image with better image quality.

In this printing apparatus, it is preferable that a plurality of the ink discharge portions are provided in a direction intersecting the predetermined direction, and the two adjustment print patterns are simultaneously formed by different ink discharge portions.
According to such a printing apparatus, since a plurality of ink discharge portions are provided in a direction intersecting the predetermined direction, it is possible to simultaneously print the adjustment print patterns one by one with different ink discharge portions. is there. For this reason, since two adjustment printing patterns are printed simultaneously, it is possible to shorten a required time.

In such a printing apparatus, the two adjustment print patterns may be formed by the same ink ejection unit.
Since the ink ejection characteristics of different ink ejection sections are different, they are caused by the ink ejection characteristics of the individual ink ejection sections when the two adjustment print patterns are formed in the same ink ejection section. It is possible to eliminate the density difference of the adjustment print pattern. For this reason, it is possible to adjust more accurately by adjusting the relative positions of the dots based on the two adjustment print patterns formed by the same ink discharge section.

In the printing apparatus, it is preferable that the two adjustment print patterns are formed adjacent to each other in a direction intersecting the predetermined direction.
According to such a printing apparatus, it is possible to form two adjustment print patterns used for eliminating waviness or the like of the medium at a position closer to the medium. For this reason, since the two adjacent adjustment print patterns are printed in a substantially similar medium state, if the influence of waviness or the like is eliminated using the two adjacent adjustment print patterns, It is possible to accurately eliminate the influence of waviness and the like. For this reason, it is possible to adjust the relative positions of the dots more appropriately.

  In such a printing apparatus, even if the medium is wavy due to the ink ejected onto the medium, the influence of the waviness and the like can be eliminated by using two adjustment printing patterns. It is possible to adjust the position.

Also, (a) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on the medium, (b) a light emitting unit that emits light, and a light receiving unit that outputs a signal based on the received light (C) differentiating the relative positions in the predetermined direction between the first dots formed in the ink discharge section and the second dots formed at a timing different from the first dots. Accordingly, each of the two adjustment print patterns has two adjustment print patterns each having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction. The positions of the sub-patterns in the predetermined direction are made different, and the two adjustment print patterns are printed so as to be aligned in a direction crossing the predetermined direction. A control unit that adjusts the relative position based on the output of the light receiving unit when the change in density of the print pattern in the predetermined direction is detected by the optical sensor; The change in density of the two adjustment print patterns is detected in association with the position in the predetermined direction, and based on the density difference detected in association with the same position in the predetermined direction of the output of the light receiving unit. , Adjusting the relative position, and having a plurality of adjustment values in which the relative position of the first dot and the second dot in the predetermined direction changes step by step by a predetermined amount, and each of the adjacent sub-patterns is The two adjustment print patterns are formed with the adjustment values different from each other, and the first and second dots are theoretically formed at the same position in the predetermined direction. The patterns are arranged so as to be distributed to each other around a predetermined reference position in a predetermined direction, and the difference in density detected in association with the same position in the predetermined direction of the two adjustment print patterns is positive. The relative position is adjusted based on the distance between the reference position and the position where the position is switched from negative to positive or from negative to positive, and the ink discharge portion is capable of reciprocating, and the first dot is the ink discharge The second dots are formed by movement of the ink ejection part in the backward direction, and a plurality of the ink ejection parts are provided in a direction crossing the predetermined direction. The two adjustment print patterns are formed simultaneously in different ink ejection portions, and the two adjustment print patterns are formed adjacent to each other in a direction intersecting the predetermined direction. The medium is a printing apparatus in which undulation is generated by ink ejected onto the medium.
According to such a printing apparatus, since all the effects described above are exhibited, the object of the present invention is achieved most effectively.

  An optical unit having an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on a medium, a light emitting unit that emits light, and a light receiving unit that outputs a signal based on the received light And a second dot formed at a timing different from the first dot in the predetermined direction. Density that each of the two adjustment print patterns has two adjustment print patterns each having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction by changing the relative positions. The positions of the peak sub-patterns having a peak in the predetermined direction are made different, and the two adjustment print patterns are arranged in a direction crossing the predetermined direction. And a function for adjusting the relative position based on the output of the light receiving unit when the change in density in the predetermined direction of the two adjustment print patterns is detected by the optical sensor. A computer program is also feasible.

  (A) a computer main body; (B) a printing apparatus connected to the computer main body having the following (a) to (c); and (a) ejecting ink droplets while moving in a predetermined direction. An ink ejection unit for forming dots on the medium; (b) an optical sensor having a light emitting unit that emits light; and a light receiving unit that outputs a signal based on the received light; and (c) the ink ejection unit. By arranging different relative positions in the predetermined direction between the first dot to be formed and the second dot formed at a timing different from that of the first dot, they are arranged so that the density sequentially changes along the predetermined direction. The two adjustment print patterns each having a plurality of sub-patterns, and the two adjustment print patterns each having a different density position in the predetermined direction. The two adjustment print patterns are printed so as to be aligned in a direction intersecting the predetermined direction, and the change in density of the two adjustment print patterns in the predetermined direction is detected by the optical sensor. A printing system including a control unit (C) that adjusts the relative position based on the output of the light receiving unit at the time can also be realized.

  In addition, a first dot formed in an ink discharge unit for forming a dot on a medium by discharging an ink droplet while moving in a predetermined direction, and a second dot formed at a timing different from the first dot By changing the relative positions in the predetermined direction, two adjustment print patterns having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction are converted into the two adjustment print patterns. And the step of causing the two sub-patterns for adjustment to be arranged in a direction intersecting with the predetermined direction, and changing the positions of the peak sub-patterns each having a peak density in the predetermined direction. A change in density in the predetermined direction of the print pattern for adjustment is received by a light emitting unit that emits light and a signal that is output based on the received light. And a step of setting an adjustment value for adjusting the relative position based on the output of the light receiving unit when detected. A method for adjusting the relative positions of the dots to be formed can also be realized.

=== Configuration of Printing System ===
An embodiment of a printing system according to the present invention 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 illustrating an example of 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 an ink jet printer as a printing apparatus that prints an image by ejecting ink onto 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 includes a display and displays a screen for realizing 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 when an application program is operated or a printer driver is set along the screen 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 a function of displaying a user interface screen on the display device 120 and a function of converting image data output from an 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.

=== Configuration of Printer ===
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 1 of this embodiment includes a transport unit 20, a carriage unit 30, a head unit 40, a detector group 50, and a controller 60 as a control unit. 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 a print sheet as a medium. The situation in the printer 1 is monitored by a detector group 50, and the detector group 50 outputs a detection result to the controller 60. The controller 60 that receives the detection result from the detector group 50 controls each unit based on the detection result.

  The transport unit 20 is a unit for feeding the printing paper S or the like to a printable position and transporting the print paper S or the like in a predetermined direction (hereinafter referred to as a transport direction) by a predetermined transport amount during printing. The transport unit 20 includes a paper feed roller 21, a transport motor 22, a transport roller 23, a platen 24, and a paper discharge roller 25. The paper feed roller 21 is a roller for feeding the paper inserted into the paper insertion slot into the printer 1. 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. FIG. 5 is a view showing the periphery of the drive unit of the transport unit 20. The carry motor 22 is a motor for carrying the printing paper in the carrying direction, and is constituted by a DC motor. The transport roller 23 is a roller that transports the printing paper S fed by the paper feed roller 21 to a printable area, and is driven by the transport motor 22. As shown in FIG. 5, a disk 521 provided with a plurality of slits is provided on the shaft of the conveyance roller 23 in order to detect the rotation amount of the conveyance roller 23, and a detection unit 522 provided in the main body of the printer 1. And the rotary encoder 52 is configured.

  The platen 24 supports the printing paper S being printed. FIG. 6 is a perspective view showing a printing sheet conveyed on the platen 24 by the conveying roller 23. A plurality of protrusions 242 are arranged on the platen 24 along the CR movement direction. The leading edge of the conveyed printing paper S contacts the protrusion 242 of the platen 24. The printing paper S in contact with the protrusions 242 is swelled and becomes wavy when viewed from the transport direction. In other words, the crest and trough portions of the undulating printing paper S are along the transport direction, and the crest and trough portions of the paper appear alternately in the CR movement direction. Since the printing paper S has such a shape and is conveyed in the conveyance direction, the printing paper S is conveyed without warping downward. The paper discharge roller 25 is a roller for discharging the printing paper S that has been printed out to the outside of the printer 1. The paper discharge roller 25 rotates in synchronization with the transport roller 23.

  The carriage unit 30 is a unit for moving the head 41 in a predetermined direction (hereinafter referred to as CR movement direction). The carriage unit 30 includes a carriage 31 and a carriage motor 32. The carriage 31 can reciprocate in the CR movement direction. Further, 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 CR movement direction, and is constituted by a DC motor.

  The head unit 40 is for ejecting ink onto the printing paper S. The head unit 40 has a head 41. The head 41 has a plurality of nozzles n (FIG. 8) as ink ejection units, and ejects ink intermittently from each nozzle n. The head 41 is provided on the carriage 31. Therefore, when the carriage 31 moves in the CR movement direction, the head 41 also moves in the CR movement direction. Then, the ink is intermittently ejected while the head 41 is moved in the CR movement direction, whereby dot lines (raster lines) along the CR movement direction are formed on the printing paper S.

  The detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder 51 is for detecting the position of the carriage 31 in the CR movement direction. The rotary encoder 52 is for detecting the rotation amount of the transport roller 23. Details of the linear encoder 51 and the rotary encoder 52 will be described later.

  The paper detection sensor 53 is for detecting the position of the leading edge of the paper to be printed and for detecting the presence or absence of the paper. The paper detection sensor 53 is provided at a position where the front end 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. FIG. 7 is a schematic diagram for explaining an example of the optical sensor 54. The optical sensor 54 includes, for example, a light emitting unit 54a configured by a light emitting diode and a light receiving unit 54b configured by a phototransistor, for example. The light receiving unit 54b receives the reflected light applied to the printing paper S from the light emitting unit 54a, and a signal corresponding to the intensity of the received reflected light is output. Therefore, the optical sensor 54 has a function of detecting the density of the print pattern printed on the print paper S.

  The controller 60 is a control unit for controlling the printer. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 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 a program of the CPU 62, a work area, and the like, and is configured by a RAM, an EEPROM, or the like. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

=== About the nozzle ===
FIG. 8 is an explanatory diagram showing the arrangement of the nozzles n 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 (180 in the present embodiment) of nozzles n as ink ejection portions for ejecting ink of each color.

  The plurality of nozzles n in each nozzle group are aligned at a constant interval (nozzle pitch: k · D) along the transport direction. Here, D is the minimum dot pitch in the carrying direction (that is, the interval at the highest resolution of dots formed on the printing paper S). K is an integer of 1 or more. For example, when the nozzle pitch is 180 dpi (1/180 inch) and the dot pitch in the transport direction is 720 dpi (1/720), k = 4.

  The numbers of the nozzles n in each nozzle group are smaller as the nozzles on the downstream side are smaller (n1 to n180). That is, the nozzle n1 is located downstream of the nozzle n180 in the transport direction. Each nozzle n is provided with a piezo element (not shown) as a drive element for driving each nozzle n to eject ink droplets. Further, the optical sensor 54 is located at substantially the same position as the most upstream nozzle n180 with respect to the position in the transport direction.

=== Head drive ===
Next, driving of the head 41 will be described with reference to FIG. FIG. 9 is a block diagram showing the configuration of the drive signal generator provided in the unit control circuit 64 (FIG. 2).

  In FIG. 9, the drive signal generation unit includes a plurality of mask circuits 204, an original drive signal generation unit 206, and a drive signal correction unit 230. The mask circuit 204 is provided corresponding to the piezo elements for ejecting ink from the nozzles n1 to n180 of the head 41, respectively. In FIG. 9, the numbers in parentheses at the end of each signal name indicate the number of the nozzle to which the signal is supplied. The original drive signal generator 206 generates an original drive signal ODRV that is commonly used for the nozzles n1 to n180. The original drive signal ODRV is a signal including two pulses, a first pulse W1 and a second pulse W2, within a CR movement period for one pixel. The drive signal correction unit 230 adjusts the ink ejection timing by shifting the timing of the drive signal DRV shaped by the mask circuit 204 based on the print signal PRT and the original drive signal ODRV back and forth in the entire return path. By adjusting the timing of the drive signal waveform, the landing positions of the ink droplets in the forward path and the return path, that is, the relative positions of the dots formed in the forward path and the return path, respectively, are adjusted.

=== About the encoder ===
Next, the rotary encoder 52 for detecting the conveyance amount of the printing paper and the linear encoder 51 for detecting the position of the carriage 31 will be described. FIG. 10 is an explanatory diagram of the configuration of the rotary encoder.

  The rotary encoder 52 includes a disk 521 provided with a slit and a detection unit 522. The slits of the disk 521 are provided at predetermined intervals along the circumferential direction of the disk 521. The disk 521 is provided on the transport roller 23. That is, the disk 521 rotates together with the rotation of the transport roller 23. For example, when the transport roller 23 rotates to transport the printing paper S for 1/1440 inches, the disk 521 rotates by one slit relative to the detection unit 522.

  The detection unit 522 is provided to face the disk 521 and is fixed to the printer 1 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 522B. The collimator lens 522B converts the light emitted from the light emitting diode 522A into parallel light, and irradiates the disk 521 with the parallel light. The parallel light that has passed through the slit provided in the disk 521 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 respective photodiodes 522D 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.

  FIG. 11A is a timing chart of the waveform of the output signal when the carry motor 22 is rotating forward, and FIG. 11B is a timing chart of the waveform of the output signal when the carry 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 22 is rotating forward or reverse. When the transport motor 22 is rotating forward, that is, when the printing paper S is transported in the transport direction, the phase of the pulse ENC-A is advanced by 90 degrees relative to the pulse ENC-B. On the other hand, when the transport motor 22 is reversed, that is, when the printing 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. ing. One period T of each pulse is equal to the time during which the transport roller 23 rotates by the interval of the slits of the disk 521 (for example, 1/1440 inch (1 inch = 25.4 mm)).

  Since the controller 60 counts the number of pulse signals, the rotation amount of the transport roller 23 can be detected, so that the transport amount of the printing paper S can be detected.

  In the rotary encoder 52, the slits provided along the circumferential direction in the disk 521 are arranged in parallel with each other at a predetermined interval in the linear encoder 51, and the scales 51a arranged along the CR moving direction are arranged. The detection unit 51b is provided on the carriage 31, but the other configurations are the same. The scale 51a is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 25.4 mm)). In the case of the linear encoder 51, every time the edge of the slit is detected, it can be detected that the carriage 31 has moved a distance corresponding to 1/4 of the slit interval.

=== About printing operation ===
FIG. 12 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 the printing paper S to be printed into the printer 1 and positioning the printing paper S at a printing start position (also referred to as a cueing position). The controller 60 rotates the paper feed roller 21 and sends the printing paper S to be printed to the transport roller 23. The controller 60 rotates the transport roller 23 to position the print paper S sent from the paper feed roller 21 at the print start position. When the printing paper S is positioned at the printing 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 the printing paper S by intermittently ejecting ink from the nozzles n while moving the head 41 along the CR movement direction. The controller 60 drives the carriage motor 32 to move the carriage 31 in the CR movement direction. Then, the controller 60 discharges ink from the head 41 based on the print data while the carriage 31 is moving. When ink droplets ejected from the head 41 land on the printing paper S, dots are formed on the paper.

  Next, the controller 60 performs a conveyance process (S004). The conveyance process is a process of moving the printing paper S relative to the head 41 along the conveyance direction. The controller 60 drives the carry motor 22 and rotates the carry roller 23 to carry the printing paper S 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 the printing paper S. When there is no more data for printing on the paper being printed, the controller 60 discharges the printing paper S. The controller 60 discharges the printed printing paper S to the outside of the printer 1 by rotating the paper discharge roller 25. 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 printing paper S, printing is continued, and a paper feeding process for the next printing paper S is started. If printing is not performed on the next printing paper S, the printing operation is terminated.

=== Print pattern for adjusting dot formation position ===
Next, an outline of adjustment of the relative position in the CR movement direction of dots formed at different timings will be described.

  As described above, the printer 1 of this embodiment forms dots on the printing paper S by ejecting ink droplets from the nozzles n provided on the head 41 while the carriage 31 reciprocates in the CR movement direction. Form an image. At this time, in the case of performing so-called bidirectional printing in which ink is ejected in both the forward path and the backward path in the CR movement direction to form dots, the first dots formed in the forward path as the first movement Therefore, it is necessary to adjust the relative position with the second dot formed in the return path as the second movement. Further, even in the case where dots are formed by ejecting ink droplets only when moving in one specific direction of either the forward path or the backward path in the CR movement direction, the movement in the specific direction as the first movement It is necessary to adjust the relative positions of the first dots that are sometimes formed and the second dots that are formed when moving in a specific direction at a different timing from the first movement as the second movement. Furthermore, it is necessary to adjust the relative position in the CR movement direction of the dots ejected from different nozzle groups when the carriage 31 moves once in one direction.

  For this reason, the relative positions of the dots are adjusted using an adjustment print pattern having a plurality of sub-patterns having different densities in the CR movement direction. At this time, each sub-pattern is formed with the first dot and the second dot formed at a different timing from the first dot. The different sub-patterns are formed at different timings for ejecting ink to form the second dots. Then, it is possible to detect the density of each sub-pattern of the formed adjustment print pattern with an optical sensor or the like, and adjust the timing of ejecting ink to form the second dot based on the detected result It is. However, as described above, the printing paper S is swelled by the protrusions 242 provided on the platen 24, and becomes wavy when viewed from the conveyance direction. Further, when ink is ejected onto the printing paper S in order to print the adjustment print pattern, the ink penetrates and a new undulation occurs. For this reason, even if the density of the printed adjustment print pattern is detected by the optical sensor 54 provided on the carriage 31 so as to face the printing paper S, the accurate density may not be detected. That is, due to the undulations occurring on the printing paper S, the distance between the optical sensor 54 and the surface of the printing paper S changes, and the correct density cannot be detected, and the relative positions of the first and second dots are appropriate. May not be adjusted. In the present embodiment, the influence on the output of the optical sensor 54 due to the undulation generated in the printing paper S is suppressed, and the relative position between the first dot and the second dot is adjusted more appropriately. Here, a case will be described in which the relative position between the first dot and the second dot when performing bidirectional printing is adjusted.

  FIG. 13 is a diagram for explaining an example of an adjustment print pattern used for adjusting the relative positions of the first dots and the second dots when performing bidirectional printing and the concept of the adjustment method.

  As shown in the drawing, in this embodiment, two adjustment print patterns 91 and 92 are used. Each of the adjustment print patterns 91 and 92 includes, for example, twelve sub patterns 91A to 91L and 92A to 92L having different densities. The twelve sub-patterns 91A to 91L and 92A to 92L are arranged in the CR movement direction so that the density changes stepwise. Each of the sub patterns 91A to 91L and 92A to 92L is formed by ejecting ink droplets from a specific nozzle row (for example, the black ink nozzle group K) while reciprocating the head 41 in the CR movement direction. At this time, ink droplets are ejected at regular intervals in the forward path, and the ejection timing is changed for each sub-pattern in the backward path.

  The adjustment print patterns 91 and 92 in FIG. 12 indicate adjustment print patterns formed when the relative positions of the first dots and the second dots are not shifted. That is, in the forward path, ink droplets are ejected onto the printing paper S at the same interval, for example, the interval at which the carriage 31 moves 1/180 inch. On the other hand, in the return path, ink droplets are ejected to form dots at similar intervals, but the ejection timing is changed for each of the sub-patterns 91A to 91L and 92A to 92L, and the amount of change is sequentially increased in the CR movement direction. Print side by side to change. At this time, the change amount of the ejection timing is the first dot formed in the forward path and the second formed in the backward path by the minimum adjustment amount (hereinafter referred to as unit adjustment amount) set to select the adjustment amount. The relative position with respect to the dots is set so as to change between adjacent sub-patterns. Here, the unit adjustment amount is the distance obtained by dividing the ideal inter-dot distance (= 1/180 inch) in the CR movement direction into, for example, eight equal parts, that is, (1/180 inch) ÷ 8 = 1/1440 inch. The sub-pattern is formed by shifting the ejection timing of the ink droplet in the return path so that the relative position is shifted.

  For example, in the sub-pattern 91A and the sub-pattern 91B, the difference between the forward ejection timing and the backward ejection timing in the sub-pattern 91A is Δt1, and the deviation between the forward ejection timing and the backward ejection timing in the sub-pattern 91B. Is Δt2, | Δt1−Δt2 | is a required time when the carriage 31 moves 1/1440 inch. Since 1/180 inch is equal to 8/1440 inch, if the difference between the discharge timing of the forward path and the discharge timing of the return path between the sub-pattern 91A and the eight adjacent sub-patterns 91I is Δt9, Δt1 = Δt9. It has become. The unit adjustment amount described above is associated with an adjustment value for adjusting the relative position of the dot, and is set so that the position of the dot formed on the return path is shifted by 1/1440 inch when the adjustment value is changed by one. ing.

  In the sub patterns 91A to 91L formed in this way, the overlap between the first dots formed on the printing paper S in the forward path and the second dots formed on the printing paper S in the backward path is larger. The density of the sub-pattern decreases, and the smaller the overlap between the first dot formed on the printing paper S in the forward path and the second dot formed on the printing paper S in the backward path, the lower the density of the sub-pattern. Get higher.

  The two adjustment print patterns 91 and 92 are arranged side by side in the transport direction. At this time, the sub patterns having the lowest density of the respective adjustment print patterns 91 and 92 are formed at different positions in the CR movement direction. Specifically, for example, when dots are formed at the target position when ink is ejected at the timing of the design value (as the theoretical value) in the forward path and the return path, the sub-pattern that should have the lowest density is The printing paper S is arranged in the left-right direction with the reference position CL being the center in the CR movement direction as the center. In FIG. 13, the sub-pattern 91E that should have the lowest density in the adjustment print pattern 91 is located on the left side by three sub-patterns from the reference position CL, and the sub-pattern 92H that should have the lowest density in the adjustment print pattern 92. Are located to the right of three sub-patterns from the reference position CL. Here, the reference position is not necessarily the center in the CR movement direction of the printing paper S.

  The adjustment print patterns 91 and 92 first form the upper adjustment print pattern 91 using, for example, the first nozzle n1 to the 90th nozzle n90 when the carriage 31 moves in the forward direction. Ink is ejected at predetermined intervals to form dots. Next, when the carriage 31 moves in the backward direction, the adjustment value is changed so that the adjustment value differs by 1 for each sub-pattern, and ink is ejected to form dots. At this time, the sub patterns 91 </ b> A to 91 </ b> L are formed at predetermined positions based on the outputs of the linear encoder 51 and the rotary encoder 52. Further, the adjustment value “0” is theoretically set so that the first dot and the second dot overlap at the position of the sub-pattern 91E in FIG. 13, and is positioned on the right side of the sub-pattern 91E. The sub patterns are sequentially changed to “+1”, “+2”..., And the sub patterns located on the left side are sequentially changed to “−1” “−2”.

  Next, the printing paper S is conveyed by the size of the adjustment print pattern in the conveyance direction. Thereafter, the carriage 31 is moved in the forward direction, and using the first nozzle n1 to the 90th nozzle n90, ink is ejected at a predetermined interval to a region where the lower adjustment print pattern 92 is formed, thereby forming dots. To do. That is, the ink is ejected so that the first sub pattern 92A in the lower adjustment print pattern 92 is positioned adjacent to the fourth sub pattern 91D in the upper adjustment print pattern 91 in the transport direction. Dots are formed in areas corresponding to the number of sub patterns. Then, the carriage 31 is moved in the backward direction, and ink is ejected and dots are formed while the adjustment value is changed so that the adjustment value is different by 1 in each sub-pattern. At this time, the adjustment value “0” is theoretically set so that the first dot and the second dot overlap at the position of the sub-pattern 92H in FIG. The sub-patterns to be changed are sequentially changed to “+1”, “+2”..., And the sub-patterns positioned on the left side are sequentially changed to “−1”, “−2”. The two adjustment print patterns 91 and 92 printed in this way are formed adjacent to each other in the transport direction.

  In this embodiment, the example in which the adjustment print pattern is printed using the black ink has been described. However, the adjustment print pattern may be printed using the ink of another color.

=== Outline of adjusting method of relative position of dots ===
A waveform 1 in FIG. 13 shows an ideal output as a curve when the density of each of the sub-patterns 91A to 91L in the upper adjustment print pattern 91 is detected by the optical sensor 54. A waveform 2 in FIG. 13 shows a curve of an ideal output when the optical sensor 54 detects the density of each of the sub-patterns 92A to 92L in the lower adjustment print pattern 92. A waveform 3 in FIG. 13 is a curve showing a difference between an output based on the upper adjustment print pattern 91 and an output based on the lower adjustment print pattern 92 at the same position in the CR movement direction.

  As described above, in the sub-pattern formed with the adjustment value “0”, the upper adjustment print pattern 91 is on the left side of the reference position CL, and the lower adjustment print pattern 92 is on the right side. They are arranged at an equal distance from the reference position CL. For this reason, when the relative positions of the first dot and the second dot are not shifted, the peak of the output of the optical sensor 54 is detected at an equal distance from the reference position CL. Therefore, when the difference between the output based on the upper adjustment print pattern 91 and the output based on the lower adjustment print pattern 92 is obtained, the difference in output decreases from a positive value to a negative value as shown by the waveform 3 in FIG. The position that changes to the value of coincides with the reference position CL. That is, the difference between the output based on the upper adjustment print pattern 91 and the output based on the lower adjustment print pattern 92 is obtained, and the position where the difference value changes from a positive value to a negative value is the reference position CL. When the value matches, the adjustment amount as the design value, that is, the adjustment amount “0” is set.

  Next, a case where the relative positions of the first dot and the second dot are shifted will be described. FIG. 14 is a diagram for explaining the concept of two adjustment print patterns and adjustment value setting methods that are printed when the relative positions of the first dots and the second dots are shifted. In the adjustment patterns 93 and 94 in FIG. 14, the sub pattern with the lowest density (hereinafter referred to as a peak sub pattern) is an adjustment print pattern 91 when the relative positions of the first dot and the second dot are not shifted. , 92 are formed on the right side by one sub-pattern.

  A waveform 4 in FIG. 14 shows a curve of an ideal output when the optical sensor 54 detects the density of each of the sub patterns 93 </ b> A to 93 </ b> L in the upper adjustment print pattern 93. A waveform 5 in FIG. 14 represents an ideal output as a curve when the density of each of the sub-patterns 94A to 94L in the lower adjustment print pattern 94 is detected by the optical sensor 54. A waveform 6 in FIG. 14 is a curve showing a difference between an output based on the upper adjustment print pattern 93 and an output based on the lower adjustment print pattern 94 at the same position in the CR movement direction.

  As shown by the waveform 6, when the difference between the output based on the upper adjustment print pattern 93 and the output based on the lower adjustment print pattern 94 is obtained, the position where the output difference changes from a positive value to a negative value is The position corresponds to the right side of one sub pattern from the reference position CL. Therefore, the difference between the output based on the upper adjustment print pattern 93 and the output based on the lower adjustment print pattern 93 is obtained, the position where the difference value changes from a positive value to a negative value, and the reference position The product of the number of sub-patterns corresponding to the distance Δx from CL and the unit adjustment amount (here, 1/1440 inch) when the adjustment print patterns 93 and 94 are printed is set as the adjustment amount.

  By the way, as described above, the print paper S on which the adjustment print pattern is printed has cockling caused by the protrusions 242 of the platen 24 and ink. For this reason, the output of the optical sensor 54 that detects the density of the adjustment print pattern includes noise components caused by cockling or the like, but two adjustment print patterns are used as in the above-described embodiment. By doing so, it is possible to eliminate noise components due to cockling or the like and adjust more appropriately.

  A waveform 7 in FIG. 14 is a curve showing only noise components due to cockling or the like. In this embodiment, only the noise component due to cockling or the like is not detected by the optical sensor 54, but is shown for convenience of explanation. A waveform 8 in FIG. 14 is a curve indicating an output when the density of the upper adjustment print pattern 93 including a noise component is detected. A waveform 9 in FIG. 14 is a curve showing an output when the density of the lower adjustment print pattern 94 including a noise component is detected. A waveform 10 in FIG. 14 shows a difference between an output including a noise component based on the upper adjustment print pattern 93 and an output including a noise component based on the lower adjustment print pattern 94 at the same position in the CR movement direction. It is a curve.

  Each of the waveform 8 and the waveform 9 includes a noise component due to cockling or the like, and is different from curves (waveform 4 and waveform 5) indicating the output of the same adjustment print pattern. However, the curve (waveform 10) showing the difference between the output based on the upper adjustment print pattern 93 and the output based on the lower adjustment print pattern 94 at the same position in the CR movement direction includes a noise component due to cockling or the like. A curve that is almost the same as the curve (waveform 6) in the absence is shown. That is, cockling or the like is performed by adjusting the relative positions of the first dots and the second dots based on the two adjustment print patterns in which the positions of the sub patterns whose density should be the lowest are different in the CR movement direction. It is possible to suppress the influence of noise components.

=== Adjustment Value Setting Method Using Adjustment Print Pattern ===
FIG. 15 is a flowchart for explaining the adjustment value setting procedure. 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 1 receives an instruction signal instructing printing of two adjustment print patterns (S101). This instruction signal may be received from the computer main body or may be input from a button provided on the printer. When instructing the printing of the adjustment print pattern from the computer 110, for example, a user interface screen as shown in FIG. 16 is displayed on the display device 120 connected to the computer 110. The display in the window 70 of the display device 120 includes a button 71 for instructing printing of an adjustment print pattern for adjusting the relative positions of the dots. When the user clicks this button 71, a signal instructing printing of two adjustment print patterns is transmitted from the computer 110 to the printer 1 side.

  Next, the printer 1 prints two adjustment print patterns (S102). The printer 1 that has received the instruction signal searches the adjustment print pattern data in the memory 63 for information related to the adjustment print pattern for adjusting the ink ejection timing. Then, the printer 1 prints the adjustment print pattern on the printing paper S according to the information regarding the adjustment print pattern.

  After printing the adjustment print pattern, the user sets the printing paper S on which the adjustment print pattern is printed on the printer 1 and performs an operation for adjusting the relative position of the dots (S103). The controller 60 that has detected the signal for executing the adjustment transmitted by the user operation feeds the printing paper S and transports it to the first density detection position (S104). The first density detection position is a position where the upper adjustment print pattern and the optical sensor 54 face each other when the carriage 31 reciprocates. When the printing paper S is conveyed to the first density detection position, the controller 60 moves the carriage 31 and detects the density of the upper adjustment print pattern by the optical sensor 54 (S105). At this time, the output of the linear encoder 51 is also detected, and the position information in the CR movement direction and the density information of the upper adjustment print pattern are associated and stored in the memory 63 as first adjustment information (S106).

  Next, the controller 60 conveys the printing paper S to the second density detection position (S107). The second density detection position is a position where the lower adjustment print pattern and the optical sensor 54 face each other when the carriage 31 reciprocates. When the printing paper S is conveyed to the second density detection position, the controller 60 moves the carriage 31 and detects the density of the lower adjustment print pattern by the optical sensor 54 (S108). At this time, the output of the linear encoder 51 is also detected, and the position information in the CR movement direction and the density information of the lower adjustment print pattern are associated and stored in the memory 63 as second adjustment information (S109).

  The controller 60 detects a peak subpattern having a peak density from the first adjustment information and the second adjustment information stored in the memory 63, and acquires position information of the peak subpattern (S110). Next, based on the acquired two pieces of position information, density information and position information in the region indicated by the two pieces of position information are extracted from the first adjustment information and the second adjustment information, respectively (S111). ). The difference between the density information of the first adjustment information and the density information of the second adjustment information at the same position in the CR movement direction based on the density information and the position information extracted from the first adjustment information and the second adjustment information, respectively. Is stored in the memory 63 in association with the position information (S112).

Next, from the density difference information stored in the memory 63, a place where the density difference changes from a positive value to a negative value, that is, a place where the density difference becomes “0” is detected. Is acquired as 0 position information (S113).
The controller 60 determines an adjustment value based on the acquired 0 position information and the adjustment value data table stored in the memory 63, and rewrites the adjustment value stored in the memory 63 (S114).

  The adjustment value data table is a data table for associating position information with adjustment values. FIG. 17 is a diagram illustrating an example of the concept of the adjustment value data table. In this example, the position information is indicated by the distance from the reference position CL, with the reference position CL being the center in the CR movement direction of the two adjustment patterns being “0”. Since the sub pattern is formed by changing the adjustment value stepwise, the association between the adjustment value and the position information is performed every time the width of the sub pattern in the CR movement direction, for example, the position information changes by 10 mm. The adjustment value is set to change. For this reason, when the adjustment print pattern is printed and the output of the optical sensor 54 is the waveform 10 shown in FIG. 14, the density difference detected by the optical sensor is “0”. “+10” is acquired as the position information at the center of the patterns 91I and 92F. Then, the adjustment value used at the time of bidirectional printing of the printer 1 is determined as the adjustment value “+1” associated with the acquired position information “+10”, and is rewritten with the adjustment value stored in the memory 63.

  The process for determining the adjustment value described above may be performed on the computer main body side or on the printer main body side. When it is performed on the computer main body side, the determined adjustment value is transmitted from the computer main body side to the printer side. Then, the printer stores the received adjustment value in the memory 63 in the printer.

  That is, when the image is bidirectionally printed on the printing paper S, the controller 60 reads the adjustment value stored in the memory 63 and adjusts the ink ejection timing of the nozzle (head) based on the adjustment value. To do. As a result, the relative position between the first dot and the second dot is adjusted, and the image quality can be improved.

  According to the printer 1 of the present embodiment, the two adjustment print patterns are formed with different positions in the CR movement direction of the peak sub-patterns included in the respective adjustment print patterns. It is possible to print the peak sub-patterns of the respective adjustment print patterns at parts having different situations. That is, it is possible to form sub-patterns having the same relative position between the first dot and the second dot among the sub-patterns included in each adjustment print pattern at different positions in the CR movement direction. Since the two adjustment print patterns are printed so as to be aligned in the transport direction, each adjustment print pattern has two sub-patterns having different densities at substantially the same position in the CR movement direction of the printing paper. become. Since almost the same position in the CR movement direction of the printing paper has almost the same undulation, it is possible to acquire two pieces of information affected by the undulation similarly as the output of the light receiving unit. For this reason, it is possible to obtain information from which the influence of waviness and the like is eliminated from the two pieces of information, and it is possible to adjust the relative position more accurately using the information from which the influence of waviness and the like is eliminated.

  The two adjustment print patterns 91 and 92 of the present embodiment are included in each of the adjustment print patterns 91 and 92, and the sub patterns 91E and 92H having the theoretically lowest density are the reference positions CL in the CR movement direction. Arranged to be distributed as the center. In the sub-pattern in which the first dot and the second dot are theoretically formed at the same position in the CR movement direction, the first dot formed in the forward path and the second dot formed in the backward path overlap each other. The area occupied by dots formed per area is narrowed, and the density becomes the lowest peak. For this reason, in a state where the adjustment print pattern is printed, when the first dot and the second dot overlap, that is, when adjustment is not necessary, the sub-pattern having the lowest theoretical density is They are arranged equidistant from the reference position CL. The two adjustment print patterns include a sub-pattern 91E having the lowest theoretical density of the upper adjustment print pattern 91 and a peak having the lowest theoretical density of the lower adjustment print pattern 92. The density changes in reverse with the sub-pattern 92H.

  When the difference between the density detected by the upper adjustment pattern 91 and the density detected by the lower adjustment pattern 92 is obtained at the same position in the CR movement direction, the calculated information is The maximum value (positive value) is at the lowest density position of the adjustment print pattern, and the minimum value (negative value) is the lowest density position of the other adjustment print pattern. That is, the difference in density between the two adjustment print patterns at the same position in the CR movement direction changes from a positive value to a negative value between the peak sub-patterns of the two adjustment print patterns. At this time, when the first dot and the second dot of the sub-pattern that should originally overlap the first dot and the second dot overlap, the position where the density difference turns from a positive value to a negative value Is positioned between the peak sub-patterns of the two adjustment print patterns, that is, at the reference position CL.

  On the other hand, when the adjustment print pattern is printed and the first dot and the second dot of the sub-pattern where the first dot and the second dot should originally overlap each other, the two adjustment prints All of the peak sub-patterns having the lowest pattern density are formed at positions shifted by a predetermined amount. For this reason, when the difference between the density detected by the upper adjustment print pattern and the density detected by the other adjustment print pattern is obtained at the same position in the CR movement direction, a negative value is obtained from a positive value. The position of turning to the value will deviate from the reference position CL. Therefore, by adjusting the relative position based on the shifted distance Δx, it is possible to easily adjust the relative position with an appropriate adjustment value by eliminating the influence of waviness or the like of the printing paper.

  In the present embodiment, during bidirectional printing, the relative position between the first dot formed when the carriage 31 moves in the forward direction and the second dot formed when the carriage 31 moves in the forward direction is adjusted. As a result, it is possible to appropriately adjust the shift of the relative position between the first dot and the second dot, and to print a good image while reciprocating the ink discharge portion. In the present embodiment, the density detected by the optical sensor 54 is “positive value” when it is the lowest, and “0” when it is the highest, but “0” when it is the lowest, and when it is the highest. It may be a “positive value”. In this case, the density difference between the two adjustment print patterns at the same position in the CR movement direction is changed from a negative value to a positive value between the peak sub-patterns of the two adjustment print patterns. Become.

  In the present embodiment, the sub-patterns 91E and 92H that theoretically have the lowest density are arranged so as to be distributed around the reference position CL in the CR movement direction, and the density difference between the two adjustment print patterns is detected. Thus, the center of the sub-patterns 91E and 92H that are peaks can be set to a position where the density difference is “0”. For this reason, it is possible to facilitate the processing of the controller 60 for detecting the centers of the sub-patterns 91E and 92H having the peak concentrations.

  In this embodiment, the example in which the first dot is formed in the forward path of the carriage 31 and the second dot is formed in the backward path has been described. However, both the first dot and the second dot are in the forward direction of the carriage 31. Alternatively, it may be formed in a different movement operation by movement in any direction of the return path direction. In this case, the relative displacement between the first dot and the second dot formed by movement in any direction at different timings is appropriately adjusted, and the ink ejection unit is moved a plurality of times in a specific direction. It is possible to print a good image. The two adjustment printing patterns used at this time are, for example, ejected ink at a predetermined interval when the carriage 31 is moved in the forward direction, and then moved in the backward direction without ejecting ink after forming the first dots. Thereafter, the second dot is formed so that the relative position with respect to the first dot is different for each sub-pattern while moving the carriage 31 in the forward direction. Also in this case, the sub-patterns that should have the lowest density are formed at different positions in the CR movement direction.

  Further, when a plurality of nozzle groups capable of ejecting ink at different timings are provided in the carriage movement direction as in the head 41 of the present embodiment, the carriage 31 is moved once. In addition, the relative positions of dots formed by nozzle groups that can be ejected at different timings may be adjusted. In this case, for example, it is possible to adjust the relative positions of the dots of different colors by forming the adjustment print pattern with the dots formed by the nozzles that eject different colors of ink as the first dots and the second dots, respectively. It is possible to print a good color image. The two adjustment print patterns used at this time are, for example, ejecting ink from the magenta ink nozzle group M to form the first dot when the carriage 31 moves in the forward direction, and ejecting ink from the cyan ink nozzle group C. As a result, second dots are formed. At this time, ink is ejected from the magenta ink nozzle group M at a predetermined interval, and the second dot is formed from the cyan ink nozzle group C so that the relative position to the first dot is different for each sub-pattern. Also in this case, the sub-patterns that should have the lowest density are formed at different positions in the CR movement direction. In addition, nozzles that discharge ink of the same color are arranged side by side in the CR movement direction, and if ink can be discharged at different timings, they are formed by nozzles that discharge ink of the same color arranged in the CR movement direction. The relative positions of the dots may be adjusted.

  Further, in the present embodiment, the two adjustment print patterns are printed on the upper adjustment print pattern, and then the printing paper is conveyed, and the lower nozzle is used by using the same nozzle as the nozzle on which the upper adjustment print pattern is printed. Although an example of forming the adjustment print pattern is described, the present invention is not limited to this. For example, when the upper adjustment print pattern is printed using the first nozzle n1 to the 90th nozzle n90 and the lower adjustment print pattern is printed using the 91st nozzle n91 to the 180th nozzle n180, two adjustment prints are used. A print pattern can be printed simultaneously and can be formed in a short time. In this case, since the timings for forming the second dots of the two sub-patterns positioned above and below are different, the positions for forming the second dots are shifted in the print data for forming the adjustment print pattern. Is desirable.

=== Other Embodiments ===
The above embodiment is mainly described for a printer, among which 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, a computer system, and a program are included. Needless to say, the disclosure includes 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 printer>
In the above-described embodiment, the printer has been described. However, the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporization apparatus, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technique as that of the present embodiment may be applied to various recording apparatuses to which an ink jet technique is applied such as an apparatus and a DNA chip manufacturing apparatus. These methods and manufacturing methods are also within the scope of application. Even if this technology is applied to such a field, the liquid can be directly ejected (directly drawn) toward the object. You can go down.

<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 discharged 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.

1 is an explanatory diagram illustrating an example of an external configuration of a printing system. 1 is a block diagram of the overall configuration of a printer according to an embodiment. 1 is a schematic diagram of the overall configuration of a printer. FIG. 2 is a cross-sectional view of the overall configuration of the printer. The figure which shows the drive part periphery of a conveyance unit. FIG. 3 is a perspective view showing a printing sheet conveyed on a platen by a conveyance roller. The schematic diagram for demonstrating an example of the optical sensor 54. FIG. An explanatory view showing the arrangement of nozzles n on the lower surface of the head. The block diagram which shows the structure of the drive signal generation part provided in the unit control circuit. Explanatory drawing of a structure of a rotary encoder. FIG. 11A is a timing chart of the waveform of the output signal when the carry motor is rotating forward, and FIG. 11B is a timing chart of the waveform of the output signal when the carry motor is reversed. The flowchart of the process at the time of printing. FIG. 5 is a diagram for explaining an example of an adjustment print pattern used for adjusting the relative positions of first dots and second dots when performing bidirectional printing and the concept of an adjustment method. The figure for demonstrating the concept of the setting method of the two adjustment printing patterns and adjustment value printed when the relative position of a 1st dot and a 2nd dot has shifted | deviated. The flowchart for demonstrating the adjustment value setting procedure. The figure for demonstrating the screen of the user interface which performs the printing instruction | indication of the printing pattern for adjustment. The figure which shows an example of the concept of an adjustment value data table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer, 20 Carrying unit, 21 Paper feed roller, 22 Carrying motor, 23 Carrying roller, 24 Platen, 25 Paper discharge roller, 30 Carriage unit, 31 Carriage, 32 Carriage motor, 40 Head unit, 41 Head, 50 Detector group , 51 linear encoder, 51a scale, 51b detector, 52 rotary encoder, 53 paper detector, 54 optical sensor, 54a light emitter, light receiver, 60 controller, 61 interface unit, 62 CPU, 63 memory, 64 units Control circuit, 70 window, button, 91 adjustment print pattern, 91A to 91L subpattern, 92 adjustment print pattern, 92A to 92L subpattern, 93 adjustment print pattern, 93A to 93L subpattern, 94 Adjustment printing pattern, 94A to 94L sub-pattern, 100 printing system, 110 computer, 120 display device, 130 input device, 130A keyboard, 130B mouse, 140 recording / reproducing device, 140A flexible disk drive device, 140B CD-ROM drive device, 204 mask circuit, 206 original drive signal generation unit, 230 drive signal correction unit, 242 protrusion, 521 disk, 522 detection unit, 522A diode, 522B collimator lens, 522C detection processing unit, 522D photodiode, 522E signal processing circuit, 522Fa comparator , N nozzles, n1 to n180 nozzles, CL reference position, DRV drive signal, PRT print signal, ODRV original drive signal, W1 pulse, W2 pulse, C cyanide Kunozuru group, K black ink nozzle group, M magenta ink nozzle group, Y yellow ink nozzle group, S printing paper

Claims (15)

(A) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on a medium;
(B) an optical sensor having a light emitting unit that emits light and a light receiving unit that outputs a signal based on the received light;
(C) Along the predetermined direction by making the relative positions in the predetermined direction different between the first dot formed by the ink ejection unit and the second dot formed at a timing different from the first dot. Two adjustment print patterns having a plurality of sub-patterns arranged so that the density changes sequentially,
Printing is performed such that the positions of the peak sub-patterns having the peak density in the two adjustment print patterns in the predetermined direction are different, and the two adjustment print patterns are arranged in a direction intersecting the predetermined direction. Let
A control unit that adjusts the relative position based on an output of the light receiving unit when a change in density in the predetermined direction of the two adjustment print patterns is detected by the optical sensor;
A printing apparatus having (d). The printing apparatus according to claim 1,
A change in density of the two adjustment print patterns is detected in association with a position in the predetermined direction,
The printing apparatus, wherein the relative position is adjusted based on a difference in density detected in association with the same position in the predetermined direction of the output of the light receiving unit. The printing apparatus according to claim 1 or 2,
A plurality of adjustment values in which the relative positions of the first dots and the second dots in the predetermined direction change stepwise by a predetermined amount;
The adjacent sub patterns are formed with adjustment values different from each other. The printing apparatus according to any one of claims 1 to 3,
In the two adjustment print patterns, the sub-patterns in which the first dots and the second dots are theoretically formed at the same position in the predetermined direction are distributed to each other around a predetermined reference position in the predetermined direction. Arranged to be
Based on the distance between the reference position and the position where the difference in density detected in association with the same position in the predetermined direction of the two adjustment print patterns is switched from positive to negative or from negative to positive. A printing apparatus characterized by adjusting the relative position. The printing apparatus according to any one of claims 1 to 4,
The ink discharge portion can reciprocate, the first dot is formed by movement of the ink discharge portion in the forward direction, and the second dot is formed by movement of the ink discharge portion in the return direction. A printing apparatus. The printing apparatus according to any one of claims 1 to 4,
The ink ejection unit can reciprocate, and the first dot is formed by a movement in a specific direction of the forward direction or the backward direction of the ink ejection unit, and the second dot is different from the first movement. The printing apparatus is formed by the movement in the specific direction executed at timing. The printing apparatus according to any one of claims 1 to 4,
A plurality of the ink discharge portions are provided along a predetermined direction,
The printing apparatus according to claim 1, wherein the first dot and the second dot are formed by different ink discharge portions when the ink discharge portion moves once in a predetermined direction. The printing apparatus according to any one of claims 1 to 7,
A plurality of the ink discharge portions are provided in a direction crossing the predetermined direction,
The printing apparatus, wherein the two adjustment print patterns are simultaneously formed by different ink discharge portions. The printing apparatus according to any one of claims 1 to 7,
The printing apparatus, wherein the two adjustment print patterns are formed by the same ink ejection unit. The printing apparatus according to any one of claims 1 to 9,
The printing apparatus, wherein the two adjustment print patterns are formed adjacent to each other in a direction intersecting the predetermined direction. The printing apparatus according to any one of claims 1 to 10,
The printing apparatus according to claim 1, wherein the medium is swelled by ink ejected onto the medium. (A) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on a medium;
(B) an optical sensor having a light emitting unit that emits light and a light receiving unit that outputs a signal based on the received light;
(C) Along the predetermined direction by making the relative positions in the predetermined direction different between the first dot formed by the ink ejection unit and the second dot formed at a timing different from the first dot. Two adjustment print patterns having a plurality of sub-patterns arranged so that the density changes sequentially,
Printing is performed such that the positions of the peak sub-patterns having the peak density in the two adjustment print patterns in the predetermined direction are different, and the two adjustment print patterns are arranged in a direction intersecting the predetermined direction. Let
A control unit that adjusts the relative position based on an output of the light receiving unit when a change in density in the predetermined direction of the two adjustment print patterns is detected by the optical sensor;
(D)
A change in density of the two adjustment print patterns is detected in association with a position in the predetermined direction,
Based on the difference in density detected in association with the same position in the predetermined direction of the output of the light receiving unit, the relative position is adjusted,
A plurality of adjustment values in which the relative positions of the first dots and the second dots in the predetermined direction change stepwise by a predetermined amount;
The adjacent sub-patterns are formed with adjustment values different from each other,
In the two adjustment print patterns, the sub-patterns in which the first dots and the second dots are theoretically formed at the same position in the predetermined direction are distributed to each other around a predetermined reference position in the predetermined direction. Arranged to be
Based on the distance between the reference position and the position where the difference in density detected in association with the same position in the predetermined direction of the two adjustment print patterns is switched from positive to negative or from negative to positive. , Adjust the relative position,
The ink discharge portion can reciprocate, the first dot is formed by movement of the ink discharge portion in the forward direction, and the second dot is formed by movement of the ink discharge portion in the return direction. ,
A plurality of the ink discharge portions are provided in a direction crossing the predetermined direction,
The two adjustment print patterns are simultaneously formed in different ink discharge portions,
The two adjustment print patterns are formed adjacent to each other in a direction intersecting the predetermined direction,
The printing apparatus according to claim 1, wherein the medium is swelled by ink ejected onto the medium. An optical sensor having an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on a medium, a light emitting unit for emitting light, and a light receiving unit for outputting a signal based on the received light In a printing apparatus having
By making the relative positions in the predetermined direction different between the first dot formed by the first movement of the ink ejection unit and the second dot formed at a timing different from the first dot, the predetermined direction Two adjustment print patterns having a plurality of sub-patterns arranged so that the density sequentially changes along
Printing is performed such that the positions of the peak sub-patterns having the peak density in the two adjustment print patterns in the predetermined direction are different, and the two adjustment print patterns are arranged in a direction intersecting the predetermined direction. Let
A computer program for realizing a function of adjusting the relative position based on the output of the light receiving unit when the change in density in the predetermined direction of the two adjustment print patterns is detected by the optical sensor. . (A) a computer body;
(B) a printing apparatus connected to the computer body and having the following (a) to (c):
(A) an ink ejection unit for ejecting ink droplets while moving in a predetermined direction to form dots on the medium;
(B) an optical sensor having a light emitting unit that emits light and a light receiving unit that outputs a signal based on the received light;
(C) By making the relative position in the predetermined direction different between the first dot formed by the ink discharge portion and the second dot formed by a timing different from the first dot, Two adjustment print patterns having a plurality of sub-patterns arranged so that the density sequentially changes along the
The positions of the peak sub-patterns having the peak in density in each of the two adjustment print patterns in the predetermined direction are made different, and the two adjustment print patterns are printed in a direction intersecting the predetermined direction. ,
A control unit that adjusts the relative position based on an output of the light receiving unit when a change in density of the two adjustment print patterns in the predetermined direction is detected by the optical sensor;
A printing system comprising (C). The first dot formed by the ink discharge unit for discharging the ink droplet while moving in a predetermined direction to form the dot on the medium, and the second dot formed at a timing different from the first dot. Two adjustment printing patterns having a plurality of sub-patterns arranged so that the density sequentially changes along the predetermined direction by changing the relative positions in the predetermined direction,
Printing is performed such that the positions of the peak sub-patterns having the peak density in the two adjustment print patterns in the predetermined direction are different, and the two adjustment print patterns are arranged in a direction intersecting the predetermined direction. Step to
Detecting changes in density of the two adjustment print patterns in the predetermined direction by optical sensors each having a light emitting unit that emits light and a light receiving unit that outputs a signal based on the received light;
Setting an adjustment value for adjusting the relative position based on the output of the light receiving unit when detected;
A method for adjusting the relative position of dots to be formed.