JP2009096122A - Moving section determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly convey a medium by performing determination so that the relative positional relation between a target moving section and an actual kick occurrence position is a predetermined positional relation. <P>SOLUTION: A moving section determination method is configured to include: a step of measuring a position in the conveying direction of the medium when the state of the medium is shifted from a state where the medium is conveyed by both of a pair of upstream side conveying rollers and a pair of downstream side conveying rollers to a state where the medium is conveyed by only one of the both; and a step of determining the target moving section of the medium in a conveying operation where the medium is conveyed to pass through the measured position, in the conveying operation for liquid discharge processing which is executed in such a manner that the conveying operation where the medium is conveyed by at least one of the both and a discharge operation where liquid is discharged to the medium are alternately repeated, so that the relative positional relation between the target moving section and the measured position is the predetermined relational position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a moving section determination method.

  It is executed by alternately repeating a transport operation in which the medium is transported by at least one of the pair of upstream transport rollers and the pair of downstream transport rollers and a discharge operation in which the liquid is discharged onto the medium. Liquid ejection processing is already known (see, for example, Patent Document 1).

By the way, if the state of the medium shifts from the state where the medium is transported by the both to the state where the medium is transported by only one of the both during execution of the transport operation in the liquid discharge process, a transport error is generated. (This phenomenon is called kicking off).
JP-A-5-96796

  In order to appropriately transport the medium in consideration of the occurrence of kicking, a position where the medium is positioned in the transporting direction (hereinafter referred to as kicking occurrence position) in the transporting operation of the liquid ejection process is referred to as the medium. It is necessary to determine the target movement section of the medium in the conveyance operation of conveying the medium so that the medium passes so that the relative positional relationship between the target movement section and the kicking occurrence position is a predetermined positional relationship.

  Conventionally, the kicking occurrence position has been predicted based on experience and the like. For this reason, conventionally, the target movement section has been determined based on the predicted kicking occurrence position. However, the actual kicking occurrence position may be different from the predicted kicking occurrence position. In such a case, the relative positional relationship between the target movement section determined based on the predicted kicking occurrence position and the actual kicking occurrence position is not a predetermined positional relationship, and as a result, the medium is transported appropriately. There is a risk of being lost.

  The present invention has been made in view of such problems, and an object of the present invention is to appropriately convey a medium.

  In order to solve the above-described problem, the main invention is that (A) the medium is transported by only one of the two from the state in which the medium is transported by both the pair of upstream transport rollers and the pair of downstream transport rollers. A step of measuring the position of the medium in the transport direction when the state of the medium transitions to a transported state; and (B) a transport operation in which the medium is transported by at least one of the two and the medium The medium in the transport operation in which the medium passes through the measured position among the transport operations of the liquid discharge process executed by alternately repeating the discharge operation for discharging the liquid. And (C) a step of determining a target movement section of the target movement section so that a relative positional relationship between the target movement section and the actually measured position is a predetermined positional relation. It is between determination method.

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

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

  First, (A) the state of the medium is changed from a state where the medium is conveyed by both the pair of upstream conveyance rollers and the pair of downstream conveyance rollers to a state where the medium is conveyed by only one of the both. The step of actually measuring the position of the medium in the transport direction, and (B) a transport operation in which the medium is transported by at least one of the both and a discharge operation in which liquid is ejected to the medium alternately The target movement section of the medium in the conveyance operation of the liquid discharge process executed by being repeated so that the medium is conveyed so as to pass the actually measured position is referred to as the target movement section. A step of determining the relative positional relationship with the measured position to be a predetermined positional relationship, and a moving section determination method including (C).

  In such a moving section determination method, the target moving section is more appropriately determined based on the actually measured position (that is, the actually measured kicking occurrence position). That is, as a result of determining the target movement section based on the actually measured kicking occurrence position, the relative positional relationship between the target movement section determined based on the kicking occurrence position predicted from experience and the actual kicking occurrence position This eliminates the conventional problem that is not in a predetermined positional relationship. Thereby, it becomes possible to convey a medium appropriately.

  Further, in the moving section determining method, in the step of determining the target moving section, the target moving section is adjusted by adjusting a positioning position when the medium is positioned in the transport direction at the start of the liquid discharge process. The relative positional relationship may be determined to be a predetermined positional relationship. In such a case, determination of the target movement section becomes easier.

  Further, in the above-described movement section determination method, in the step of determining the target movement section, the target movement section is determined by comparing the relative position relationship between the center position in the transport direction of the target movement section and the actually measured position. It is good also as determining so that it may become the positional relationship which matches. In such a case, a method of determining the target movement section based on the actually measured kicking occurrence position becomes more meaningful.

  In the moving section determination method, in the step of measuring the position, the position is actually measured for each type of medium, and in the step of determining the target moving section, the positioning position is adjusted by the type, The target movement section may be determined for each type so that the relative positional relationship is a predetermined positional relationship. In such a case, it is possible to appropriately determine the target movement section in consideration of the fact that the kicking occurrence position differs depending on the type of medium.

  In the moving section determination method, in the step of actually measuring the position, the position is actually measured for two different types of media, and the step of determining the target moving section is common to the types. The target movement section may be determined according to the type so that the relative positional relationship becomes a predetermined positional relationship. In such a case, it is not necessary to adjust the positioning position for each type of medium, and it is possible to save the capacity for storing information related to the positioning position.

=== About the printer ===
The liquid discharge process according to the present embodiment will be described using a specific example of a print process in which an ink that is an example of a liquid is discharged onto a medium and an image is printed on the medium.

<< Basic printer configuration >>
First, a basic configuration of an ink jet printer (hereinafter, printer 1) as an example of a printing apparatus that performs printing processing will be described with reference to FIGS. 1, 2A, and 2B. FIG. 1 is a block diagram of the overall configuration of the printer 1. FIG. 2A is a schematic diagram of the overall configuration of the printer 1. FIG. 2B is a cross-sectional view of the overall configuration of the printer 1. In FIG. 2A, the conveyance direction of the medium and the scanning direction of the head 41 are indicated by arrows. Moreover, the said conveyance direction is shown by the arrow in FIG. 2B.

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

  The transport unit 20 is for transporting paper in a predetermined direction (transport direction). The transport unit 20 includes a paper feed roller 21, a transport motor (hereinafter referred to as a PF motor 22), a pair of upstream transport rollers 23, a platen 24, and a pair of downstream transport rollers 25 (FIG. 2A). And FIG. 2B). The paper feed roller 21 is a roller for feeding the paper inserted into the paper insertion slot into the printer. The upstream side conveyance roller 23 includes a paper feed roller 23a and a driven roller 23b, and is provided on the upstream side of the platen 24 in the paper conveyance direction. The paper feed roller 23 a of the upstream side conveyance roller 23 is driven by the PF motor 22. The platen 24 supports the paper being printed. The downstream-side transport roller 25 includes a discharge roller 25a and a driven roller 25b, and is provided on the downstream side of the platen 24 in the transport direction. The paper discharge roller 25a of the downstream side conveyance roller 25 rotates in synchronization with the paper feed roller 23a. The details of the upstream side conveyance roller 23 and the downstream side conveyance roller 25 will be described later.

  As shown in FIG. 2A, the carriage unit 30 includes a carriage 31 and a carriage motor 32, and moves in the scanning direction in order to move a later-described head 41 in a predetermined direction (hereinafter referred to as a scanning direction). Further, the carriage 31 detachably holds an ink cartridge that stores ink.

  As shown in FIG. 2A, the head unit 40 includes a head 41 having a plurality of nozzles (see FIG. 3) on its lower surface. Since the head 41 is provided on the carriage 31, the head 41 moves in the scanning direction as the carriage 31 moves. Then, ink is intermittently ejected from the nozzles while the head 41 is moving, so that dot lines (raster lines) along the scanning direction are formed on the paper.

  The detector group 50 includes a linear encoder 51 for detecting the position of the carriage 31 in the scanning direction, a rotary encoder 52 for detecting the rotation amount of the paper feed roller 23a, and the position of the leading edge of the paper being fed. A paper detection sensor 53 for detecting the presence of the paper, an optical sensor 54 for detecting the presence or absence of paper, and the like. The optical sensor 54 can also detect the leading edge and the trailing edge of the paper depending on the situation.

  The controller 60 is for controlling the printer 1. The controller 60 includes an interface 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface 61 transmits and receives data between the computer 110 and the printer 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer. The memory 63 has a storage element such as a RAM or an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

<< About the transport roller >>
Both the upstream-side transport roller 23 and the downstream-side transport roller 25 are rollers that transport the paper in the transport direction by rotating while sandwiching the paper. Hereinafter, a state in which the paper in the printer 1 is moved in the transport direction by the upstream transport roller 23 and the downstream transport roller 25 will be described.

  The paper fed into the printer 1 by the paper feed roller 21 is first sandwiched between the paper feed roller 23a and the driven roller 23b and is transported in the transport direction only by the upstream transport roller 23. If the paper continues to be conveyed in the conveying direction while maintaining the state of being sandwiched between the upstream conveying rollers 23, the end (tip) on the downstream side in the conveying direction of the paper eventually becomes between the paper discharge roller 25a and the driven roller 25b. Sandwiched between. That is, the paper is pinched by both the upstream side conveyance roller 23 and the downstream side conveyance roller 25, and the paper is further conveyed downstream by the both. If the paper continues to be conveyed while being held between the two, the upstream end (rear end) of the paper in the conveyance direction will eventually move away from the upstream conveyance roller 23. In other words, the paper is sandwiched only by the downstream-side transport roller 25 of the both sides, and thereafter, the paper is continuously transported in the transport direction only by the downstream-side transport roller 25 and finally discharged out of the printer. Is done.

<< About the nozzle >>
Next, the nozzle arrangement on the lower surface of the head 41 will be described with reference to FIG. FIG. 3 is a diagram showing the nozzle arrangement. In the drawing, the conveyance direction and the scanning direction are indicated by arrows.

 As shown in FIG. 3, 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 on the lower surface of the head 41. Each nozzle group includes 90 nozzles for ejecting ink of a color corresponding to each nozzle group.

  A plurality of nozzles in each nozzle group are aligned at a constant interval (nozzle pitch: k · D) along the transport direction to form a nozzle row. In FIG. 3, the nozzles constituting each nozzle row are assigned a smaller number for the nozzles on the downstream side (# 1 to # 90). Here, D is the minimum dot pitch (interval at the highest resolution of dots formed on the paper) in the transport direction. Further, k is an integer equal to or greater than 1. In this embodiment, since the nozzle pitch is 90 dpi (1/90 inch) and the dot pitch in the transport direction is 720 dpi (1/720 inch), k = 8. is there. The optical sensor 54 is substantially at the same position as the nozzle # 90 on the most upstream side in the direction along the transport direction.

  Each nozzle is provided with an ink chamber and a piezo element (both ink chamber and piezo element are not shown). When the ink chamber expands and contracts by driving the piezo element, ink drops from the nozzle. Discharged.

<< About print processing >>
Next, a printing process for printing an image on paper will be described with reference to FIG. FIG. 4 is a flowchart of the printing process.

  As shown in FIG. 4, the printing process includes a print data reception operation (S001), a paper feed operation (S002), a transport operation (S003), a dot formation operation (S004), and a paper discharge operation (S005). Each operation is executed by the controller 60 controlling each unit.

  The print data reception operation is an operation in which the controller 60 receives print data from the computer 110 via the interface 61. The controller 60 analyzes various commands included in the print data and controls each unit to perform the following operations.

  The paper feeding operation is an operation of feeding paper into the printer 1 by the paper feeding roller 21. The transport operation is an operation of transporting paper in the transport direction by at least one of the upstream transport roller 23 and the downstream transport roller 25. Then, the controller 60 moves the paper relative to the head 41 in the transport direction by causing the transport roller to perform a transport operation. Each time a new sheet is fed, a conveying operation for positioning the sheet at the cueing position is executed as the first conveying operation. The cue position corresponds to a positioning position when the paper is positioned in the transport direction at the start of the printing process, and the following dot formation operation can be started when the paper is positioned at the cue position.

  The dot forming operation is an ink discharging operation, in which ink is intermittently discharged from the nozzles of the head 41 moving in the scanning direction to form a raster line composed of a plurality of dots on the paper. The dot forming operation and the carrying operation are repeatedly performed alternately. As a result, when the carrying operation is performed after the dot forming operation for forming a raster line at a certain position on the paper is performed, the next dot forming operation is performed at a position different from the certain position on the paper (different in the carrying direction). It is possible to form a raster line at (position).

  Then, based on the print data received by the print data receiving operation, when the dot forming operation is repeatedly performed alternately with the transport operation, a plurality of raster lines are eventually aligned on the paper along the transport direction on the paper. The image is printed. When the printing of the image is completed, the controller 60 causes the downstream transport roller 25 to execute a paper discharge operation for discharging the paper out of the printer 1.

  Thereafter, the controller 60 determines whether or not to continue printing. When printing on the next sheet, the controller 60 returns to the paper feeding operation and continues the printing process. On the other hand, when printing is not performed on the next paper, the printing process ends.

<< Raster line formation >>
The printing process according to the present embodiment is divided into three processes, ie, upper end printing, normal printing, and lower end printing, corresponding to the raster line formation position (see, for example, FIG. 23).

  Normal printing is performed by printing (interlace printing) in which raster lines that are not recorded are sandwiched between raster lines that are recorded in one pass. “Pass” means a dot forming operation, and “pass x” means an x-th dot forming operation. In the interlaced printing according to the present embodiment, if a pass forming a raster line is defined as a pass x, in pass x + 1, a position located immediately above a certain raster line (a position positioned on the leading end side by D from a certain raster line). A raster line is formed.

  Upper end printing and lower end printing are performed in order to form raster lines at locations where raster lines cannot be formed continuously in the transport direction by normal printing alone. Top-end printing is performed before normal printing in order to form a raster line near the leading edge of the paper. The lower end printing is performed after normal printing in order to form a raster line near the rear end of the paper. Note that the transport amount (more precisely, the target transport amount before correction described later) in the transport operation executed during upper-end printing or lower-end printing is shorter than the transport amount during normal printing.

<< About bordered printing and borderless printing >>
The printer 1 according to the present embodiment can perform “marginal printing” and “marginless printing” as two printing modes having different areas (image printing areas) where paper images are printed.

  Bordered printing is a printing method in which ink is ejected so as to provide a margin of a predetermined size at the end in the paper transport direction.

  Borderless printing is a printing method in which ink is ejected to the outside of the paper in the transport direction so that no margin is formed at the end of the paper in the transport direction. In borderless printing, since ink is ejected toward the outside of the paper, ink that does not land on the paper is generated. Such ink is accumulated in an ink accumulation groove (not shown) formed in the platen 24. Further, borderless printing is started in a state where the leading edge of the paper has reached the ink accumulation groove forming position in the transport direction. This is because, in borderless printing, ink is ejected to the outside (upstream side) from the upstream end in the transport direction of the ink containing groove, so that the position where the leading edge of the paper deviates from the ink accumulation groove forming position. When borderless printing is started in this state, the ink lands on the platen 24 (so-called platen printing), and the paper moving on the platen 24 is soiled. For this reason, at the start of borderless printing, the leading edge of the paper must reach the position where the ink accumulation groove is formed. The position of the leading edge of the paper at the start of borderless printing is determined by the above-described cueing position. Therefore, the cueing position for borderless printing needs to be adjusted so that platen printing does not occur. The adjustment of the cue position will be described later.

<< Concerning the control mechanism for transport operation >>
Next, the control mechanism for the transport operation will be described with reference to FIG. FIG. 5 is a perspective view showing the transport unit 20 including the control mechanism.

  The controller 60 drives the PF motor 22 by a predetermined drive amount so that at least the upstream side conveyance roller 23 among the upstream side conveyance roller 23 and the downstream side conveyance roller 25 performs the conveyance operation. When the PF motor 22 is driven with a predetermined drive amount, the paper feed roller 23a rotates with a predetermined rotation amount. As a result, the upstream transport roller 23 transports the paper by a predetermined transport amount. Here, the carry amount of the paper is determined according to the rotation amount of the paper feed roller 23a. In the present embodiment, when the paper feed roller 23a rotates once, the paper is transported for 1 inch (that is, the circumference of the paper feed roller 23a is 1 inch). Accordingly, if the rotation amount of the paper feed roller 23a can be detected, the paper conveyance amount can also be detected. Therefore, in the present embodiment, the above-described rotary encoder 52 is provided.

  For example, when the paper is transported with a target transport amount of 1 inch, the controller 60 drives the PF motor 22 until the rotary encoder 52 detects that the paper feed roller 23a has rotated once. As described above, the controller 60 drives the PF motor 22 until the rotary encoder 52 detects that the rotation amount corresponds to the target conveyance amount.

  On the other hand, when the transport operation for transporting the paper by only the downstream transport roller 25 is executed, the rotation amount of the paper discharge roller 25a is detected. Then, the controller 60 rotates the paper discharge roller 25a until the rotation amount of the paper discharge roller 25a reaches a rotation amount corresponding to the target carry amount.

<< About transport error >>
As described above, the rotary encoder 52 detects the amount of paper transport by detecting the amount of rotation of the paper feed roller 23a. However, strictly speaking, the rotary encoder 52 does not detect the amount of paper transport. For this reason, when the rotation amount of the paper feed roller 23a does not coincide with the paper conveyance amount, the paper conveyance amount is not accurately detected, and a conveyance error due to a detection error occurs.
There are two types of transport errors due to detection errors: DC component transport errors and AC component transport errors.

  The DC component transport error is a predetermined amount of transport error that occurs when the paper feed roller 23a rotates once. The DC component transport error is considered to be caused by the fact that the circumference of the paper feed roller 23a varies from one printer to another due to manufacturing errors or the like. That is, the DC component transport error is a transport error that occurs because the designed circumference of the paper feed roller 23a is different from the actual circumference of the paper feed roller 23a. This DC component transport error is constant regardless of the starting position when the paper feed roller 23a makes one rotation, but in actuality, it varies depending on the total transport amount of paper due to the influence of paper friction and the like. become. In other words, the actual DC component transport error varies depending on the relative positional relationship between the paper and the paper feed roller 23a (or the paper and the head 41).

  The AC component transport error is a transport error according to the location of the peripheral surface of the paper feed roller 23a used during transport. The AC component transport error varies depending on the location of the peripheral surface of the paper feed roller 23a used during transport. That is, the AC component transport error varies depending on the rotational position of the paper feed roller 23a at the start of transport and the transport amount. The AC component transport error is caused by the influence of the shape of the paper feed roller 23a (for example, when the paper feed roller 23a is oval or egg-shaped), the eccentricity of the rotation axis of the paper feed roller 23a, and the paper A mismatch between the rotation axis of the feed roller 23a and the center of the scale of the rotary encoder 52 can be considered.

  Further, when the paper held between both the upstream side conveyance roller 23 and the downstream side conveyance roller 25 continues to be conveyed in the conveyance direction, the trailing edge of the paper is eventually separated from the upstream side conveyance roller 23, and the both Transition to a state of being sandwiched only by one of them (that is, the downstream transport roller 25). At this time, the above-described kicking occurs and a conveyance error occurs. More specifically, as soon as the trailing edge of the paper is separated from the upstream transport roller 23, the area of the paper sandwiched by the upstream transport roller 23 decreases. On the other hand, since the upstream conveying roller 23 sandwiches the paper, the force exerted on the paper is substantially constant. For this reason, at the moment when the rear end is separated from the upstream conveying roller 23, the clamping pressure by the upstream conveying roller 23 acts excessively on the paper. As a result, when kicking occurs during execution of a certain transport operation, the paper is transported by a transport amount that is smaller than the initial target transport amount in the certain transport operation.

  As a countermeasure against the transport error as described above, before the printer 1 is shipped, first, a process of actually measuring the position where the paper is positioned in the transport direction when the kick occurs, that is, the position where the kick is generated (hereinafter referred to as an actual process). ) Is performed. In addition, a process of acquiring a correction value for correcting the target transport amount in each transport operation (hereinafter referred to as a correction value acquisition process) is performed. The correction value reflects the paper conveyance characteristics in the printer 1 after assembly is completed, and is stored in the memory 63 included in the controller 60. Thereafter, based on the kicking occurrence position actually measured in the actual measurement process, a process for determining a target movement section of the paper in a transport operation in which the paper is transported so as to pass through the actually measured kicking occurrence position ( Hereinafter, a movement section determination process) is performed.

  After the above processing is completed, the printer 1 is shipped to the user. Under the user who purchased the printer 1, the controller 60 performs image printing processing (hereinafter, main printing) based on print data transmitted from the computer 110 owned by the user. In the actual printing, the controller 60 reads the correction value from the memory 63, corrects the initial target transport amount based on the correction value, and executes the transport operation based on the corrected target transport amount. Further, during the actual printing, when the controller 60 performs a transport operation in which the paper is transported so as to pass through the actually measured kick occurrence position, the controller 60 is determined by the movement section determination process. The transport operation is executed so that the paper moves in the target movement section. In the following description, the initial target transport amount before being corrected by the correction value is also referred to as a pre-correction target transport amount, and the corrected target transport amount is also referred to as a post-correction target transport amount.

=== Measurement processing ===
First, the above-described actual measurement process will be described with reference to FIGS. FIG. 6 is a flowchart of the actual measurement process. FIG. 7 is a diagram illustrating a state of the first test pattern printing. On the right side of the figure, a first test pattern printed on the test sheet TS is shown. The rectangle shown on the left side in the figure indicates the position of the head 41 in pass 1 and pass d. For the convenience of illustration, the head 41 is depicted as moving with respect to the test sheet TS, but this figure shows the relative position of the test sheet TS with respect to the head 41, and actually the test sheet TS. TS is transported intermittently in the transport direction. FIG. 8 is an explanatory diagram of a procedure for specifying the kicking occurrence position.

  The actual measurement process is a process of printing the first test pattern on the test sheet TS and specifying the actual kicking occurrence position based on information obtained from the first test pattern. As shown in FIG. 6, the actual measurement process includes a step of printing the first test pattern (S101), a step of reading the first test pattern (S102), and a step of specifying the kicking occurrence position from the read result (S103). Composed. Each step is performed, for example, in an inspection process at a printer manufacturing factory. The inspector connects the printer 1 after assembly to the computer 110 in the factory prior to the actual measurement process. A printer driver is installed in the computer 110 in advance.

  In the step of printing the first test pattern, first, print data for printing the first test pattern is transmitted to the printer 1 by the printer driver. A mode in which the controller 60 of the printer 1 forms a first test pattern on the test sheet TS (hereinafter referred to as a first test pattern printing) by repeatedly performing a conveyance operation and a dot formation operation alternately based on the print data. ). The test sheet TS used for the first test pattern printing is the same type (size and material) as the paper used for the main printing.

  As shown in FIG. 7, the first test pattern is composed of a plurality of ruled line patterns (hereinafter, actual measurement patterns). Each measurement pattern is a ruled line printed along the paper width direction of the test sheet TS, that is, the scanning direction of the head 41, and is formed sequentially from the leading end side of the test sheet TS. In addition, the plurality of actual measurement patterns are arranged in a direction intersecting the paper width direction on the test sheet TS. A procedure for forming such a first test pattern will be described with reference to FIG. In the following description, the i-th actual measurement pattern from the front end of the test sheet TS (that is, the actual measurement pattern printed in the path i during the first test pattern printing) is referred to as Ps (i). The theoretical position where the test sheet TS is positioned in the transport direction during pass i is referred to as the theoretical position in pass i.

  When there is a command for printing the first test pattern, the controller 60 first moves the test sheet TS from the cueing position for printing the first test pattern to a predetermined position. Thereafter, in pass 1, ink is ejected only from nozzle # 90, and Ps (1) is printed. After printing Ps (1), the controller 60 rotates the paper feed roller 23a about 1/80 to execute a transport operation for transporting the test sheet TS downstream in the transport direction by about 1/80 inch. Thereafter, in pass 2, ink is ejected only from nozzle # 90, and Ps (2) is printed. Thereafter, the same operation is repeatedly executed, and Ps (3) to Ps (d) are printed at intervals of about 1/80 inch. As described above, in the first test pattern printing, the conveyance operation and the dot formation operation are alternately performed, and as a result, d actual measurement patterns are finally printed. Then, when printing of all the actual measurement patterns is completed and the test sheet TS is discharged out of the printer, the first test pattern printing is completed.

  Here, Ps (1) is when the test sheet TS is transported by both the upstream transport roller 23 and the downstream transport roller 25, that is, when the test sheet TS is sandwiched by both (hereinafter, sandwiched state). Printed on. On the other hand, Ps (d) is a state in which the test sheet TS is transported by only one of the both, that is, a state in which the test sheet TS is sandwiched only by the downstream transport roller 25 (in other words, is sandwiched by the upstream transport roller 23). It is printed when it is in a lost state and is in a non-nipping state hereinafter. That is, the test sheet TS shifts from the pinched state to the non-pinched state between pass 1 to pass d. This means that a kicking occurrence position exists between the theoretical position in pass 1 and the theoretical position in pass d. That is, the theoretical positions in pass 1 and pass d are set so that kicking occurs between pass 1 and pass d. The theoretical position is set based on the mechanical characteristics of the printer 1 and the type of the test sheet TS.

  Next, the inspector sets the test sheet TS in a measurement device (not shown) and causes the measurement device to read the first test pattern. By measuring the first test pattern, the measuring device measures the interval between the two adjacent measurement patterns (hereinafter referred to as the pattern interval), and is significantly narrower than the original pattern interval (1/80 inch). It is possible to specify two actual measurement patterns forming the pattern interval. That is, the measurement device specifies the actual measurement patterns printed immediately before and after the occurrence of kicking. Further, the measuring device can calculate the distance from the rear end of the test sheet TS to the formation positions of the two actual measurement patterns on the test sheet TS. Then, based on the calculated distance, the inspector determines the position in the transport direction of the test sheet TS when the kicking actually occurs (in other words, the state of the test sheet TS shifts from the sandwiched state to the non-clamped state). The position in the transport direction of the test sheet TS).

  Hereinafter, the procedure for specifying the kicking occurrence position will be described with reference to FIG. In the following description, a case where kicking occurs between the path 4 and the path 5 and the pattern interval between Ps (4) and Ps (5) is significantly narrower than the original pattern interval will be described. .

  First, the distance from the rear end of the test sheet TS to the formation positions of Ps (4) and Ps (5) (indicated by L (4) and L (5) in FIG. 8) is calculated by the measuring device. . Next, based on the distance L (4) and the distance L (5), the inspector determines a position (denoted as a non-nip position in FIG. 8) on the test sheet TS that faces the nozzle # 90 when kicking occurs. Identify. Specifically, based on the distances L (4) and L (5), a distance (indicated by symbol Lk in FIG. 8) from the rear end of the test sheet TS to the non-nip position is obtained. Thereafter, the inspector, based on the distance Lk and the structure of the printer 1 (for example, the position of the upstream transport roller 25 in the transport direction), the position of the test sheet TS when the non-nip position faces the nozzle # 90, that is, kicking off. Specify the location.

=== Correction value acquisition processing ===
Next, the correction value acquisition process described above will be described with reference to FIG. FIG. 9 is a flowchart of the correction value acquisition process.

  In the correction value acquisition process, the second test pattern is printed on the test sheet TS by using the printer 1 after assembly is completed, and the correction value is calculated based on the information obtained from the second test pattern. The correction value is stored in the first memory 63. As shown in FIG. 9, the correction value acquisition process includes a step of printing the second test pattern (S111), a step of reading the second test pattern and the reference pattern (S112), a step of calculating the correction value (S113), and And the step of storing the correction value (S114). Each step is performed in the inspection process of the printer manufacturing factory, like each step of the actual measurement process. The correction value acquisition process is performed while the printer 1 and the computer 110 in the factory are connected. The inspector connects the scanner 150 to the computer 110 before the correction value acquisition process is performed. The computer 110 is preinstalled with a scanner driver and a correction value acquisition program.

  First, similarly to the first test pattern printing, the controller 60 prints the second test pattern on the test sheet TS based on the print data for the second test pattern printing transmitted by the printer driver (hereinafter referred to as the second test pattern printing). Test pattern printing). Note that the test sheet TS used for the second test pattern printing is also the same type of paper as that used for the main printing. Next, the inspector sets the test sheet TS on the scanner 150, and the scanner driver causes the scanner 150 to read the second test pattern, and acquires image data of the second test pattern. At this time, the reference sheet SS is set together with the test sheet TS in the scanner 150, and the reference pattern drawn on the reference sheet SS is also read together. Thereafter, the acquired image data is analyzed by the correction value acquisition program. Then, a correction value is calculated based on the result of the analysis. When the correction value is calculated, the correction value data is transmitted to the printer 1 and stored in the memory 63 by the correction value acquisition program.

<< Second test pattern printing >>
The step of printing the second test pattern will be described with reference to FIG. FIG. 10 is a diagram illustrating a state of the second test pattern printing. On the right side of the figure, a test pattern printed on the test sheet TS is shown. The rectangle shown on the left side in the figure indicates the position of the head 41 in each pass. FIG. 10 is also illustrated as if the head 41 has moved relative to the test sheet TS for the sake of illustration, as in FIG. 7, but this figure shows the relative position of the test sheet TS with respect to the head 41. It is shown.

  As shown in FIG. 10, the second test pattern includes an identification code and a plurality of ruled line patterns (hereinafter referred to as calculation patterns) for calculating correction values.

  The identification code is an individual identification symbol for identifying each individual printer 1, and this identification code is read when the test pattern is read, so that the printer that is the target of the correction value acquisition process is identified by the computer 110. Is done. Each of the plurality of calculation patterns is a ruled line formed along the paper width direction of the test sheet TS as in the actual measurement pattern, and is formed sequentially from the leading end side of the test sheet TS. The plurality of calculation patterns are arranged in a direction intersecting the paper width direction on the test sheet TS.

  The procedure for forming the second test pattern as described above will be described with reference to FIG. Note that the i-th calculation pattern from the leading edge of the test sheet TS (that is, the calculation pattern printed in pass i during the second test pattern printing) is P (i). In the following description, unless otherwise specified, the second test pattern is simply referred to as a test pattern, and the calculation pattern is simply referred to as a pattern.

  First, the controller 60 moves the test sheet TS to the cueing position for printing the second test pattern. Thereafter, in pass 1, ink is ejected only from nozzle # 90 and P (1) is printed. After printing P (1), the controller 60 rotates the paper feed roller 23a by 1/8 to execute a transport operation for transporting the test sheet TS by 1/8 inch. Thereafter, in pass 2, ink is ejected only from nozzle # 90 and P (2) is printed. Thereafter, the same operation is repeated, and P (3) to P (m−1) are printed at intervals of 1/8 inch. In pass 1 to pass m−1, the test sheet TS is sandwiched between at least the upstream transport roller 23 of both the upstream transport roller 23 and the downstream transport roller 25.

  After printing P (m−1), the controller 60 performs a transport operation to move the test sheet TS further downstream. Thereafter, in pass m, ink is ejected only from nozzle # 90 and P (m) is printed. At this time, the test sheet TS is sandwiched between the two, that is, in a sandwiched state. After printing P (m), the controller 60 performs a transport operation for transporting the test sheet TS further downstream by 1/6 inch. Thereafter, in pass m + 1, ink is ejected only from nozzle # 90, and P (m + 1) is printed. At this time, the test sheet TS is in the non-clamping state described above. Further, after printing P (m + 1), the controller 60 rotates the paper discharge roller 25a to execute a transport operation for transporting the test sheet TS further downstream by about 1 inch. Thereafter, in pass m + 2, ink is ejected only from nozzle # 3 and P (m + 2) is printed. Then, the second test pattern printing is completed when the test sheet TS is discharged out of the printer after the printing of P (m + 2) is completed.

  In the second test pattern printing as described above, P (m) is printed when the test sheet TS is sandwiched, while P (m + 1) is printed when the test sheet TS is unpinched. The That is, the test sheet TS shifts from the sandwiched state to the non-clamped state between the pass m and the pass m + 1. This means that a kicking position exists between the theoretical position in the path m and the theoretical position in the path m + 1. That is, the theoretical positions in the path m and the path m + 1 are set so that a kick occurs between the path m and the path m + 1 during the second test pattern printing. The theoretical position is set based on the kicking occurrence position measured in the actual measurement process. More specifically, the theoretical positions in the path m and the path m + 1 are set to positions that are separated from the actually measured kicking generation position by a deviation of the kicking generation position. More specifically, the theoretical position in the path m is set to a position that is 1/12 inch upstream in the transport direction from the measured kicking occurrence position, and the theoretical position in the path m + 1 is the occurrence of the kicking occurrence. It is set at a position located on the downstream side by 1/12 inch in the transport direction from the position. Note that the range between the theoretical positions in the path m and the path m + 1 determined in this way is hereinafter also referred to as a kicking occurrence range.

  By the way, all patterns other than P (m + 2) are printed by ejecting ink only from the most upstream nozzle # 90. Here, among the patterns printed by ejecting ink from nozzle # 90, the interval between two adjacent patterns (pattern interval) is theoretically the theoretical position in the pass for printing each of the two patterns. Equivalent to the interval (theoretical position interval). For example, the interval between two adjacent patterns in P (1) to P (m−1) is exactly 1/8 inch. The interval between P (m) and P (m + 1) is exactly 1/6 inch. However, since a conveyance error actually occurs during the conveyance operation, the pattern interval is different from the theoretical position interval. If the test sheet TS is transported more than the ideal transport amount, the pattern interval becomes wider than the theoretical position interval. Conversely, when the test sheet TS is transported less than the ideal transport amount, the pattern interval is narrowed. That is, each pattern interval reflects a transport error that occurs during each transport operation. For this reason, if the pattern interval is measured, the conveyance error can be measured, and a correction value for correcting the conveyance error can be calculated.

  Similarly, the interval between P (m + 1) and P (m + 2) is such that when the test sheet TS is conveyed ideally (more precisely, the ejection of ink from nozzle # 90 and nozzle # 3 is the same). In some cases, it should be exactly 3/90 inches, but not 3/90 inches due to transport errors. For this reason, if the interval between P (m + 1) and P (m + 2) is measured, the correction value can be calculated by measuring the transport error in the same manner as described above.

<< Reading test pattern >>
Next, the step of reading the test pattern will be described. In describing this step, first, a scanner 150 used for reading a test pattern will be described with reference to FIG. FIG. 11 is a schematic diagram showing the internal configuration of the scanner 150. In the figure, the moving direction (sub-scanning direction) of the image reading sensor 153 is indicated by an arrow. In the following description, a direction in which a plurality of light receiving elements (not shown) provided in the image reading sensor 153 are arranged and is substantially orthogonal to the sub-scanning direction is referred to as a main scanning direction.

  The scanner 150 irradiates the original G placed on the original table glass 152 with light in a state where the upper cover 151 is closed, detects the reflected light, and reads the image of the original G. As shown in FIG. 11, the scanner 150 has an image reading sensor 153 that moves in the sub-scanning direction while facing the original G through the original table glass 152, and a guide bar for moving the image reading sensor 153. A carriage 155 that moves in the sub-scanning direction along the line 154, a moving mechanism 156 for moving the carriage 155, and a scanner controller (not shown) that controls each part of the scanner are provided. Then, the image reading sensor 153 detects reflected light from the original G irradiated with light while moving in the sub-scanning direction. As a result, the image of the document G set on the document table glass 152 is read. The scanner controller transmits the read image data (image data) to the computer 110.

  The test pattern on the test sheet TS is read by the scanner 150 as described above. In the present embodiment, the scanning resolution of the scanner 150 is 720 dpi (main scanning direction) × 720 dpi (sub-scanning direction).

  By the way, regarding the reading position when the scanner 150 reads the test pattern, an error occurs between the theoretical value of the reading position and the actual reading position. If the test pattern is simply read in a state where there is an error in the reading position, the position of the pattern in the test pattern cannot be measured accurately. Therefore, in the present embodiment, when the test pattern is read by the scanner 150, the reference sheet SS is set and the reference pattern is also read.

  Hereinafter, reading of the test pattern and the reference pattern will be described with reference to FIGS. 12A and 12B. FIG. 12A is a diagram illustrating the reference sheet SS. FIG. 12B is a diagram illustrating a state where the test sheet TS and the reference sheet SS are set on the document table glass 152.

  A reference pattern is formed on the reference sheet SS. As shown in FIG. 12A, the reference pattern is composed of a plurality of lines arranged with high accuracy at intervals of 36 dpi. Then, the test sheet TS and the reference sheet SS are set at predetermined positions on the document table glass 152 as shown in FIG. 12B. The reference sheet SS is set so that each of the plurality of lines is parallel to the main scanning direction of the scanner 150. On the other hand, the test sheet TS is arranged next to the reference sheet SS, and is set so that each pattern is parallel to the main scanning direction.

  With the test sheet TS and the reference sheet SS set in this way, the scanner 150 reads the test pattern and the reference pattern. Thereby, image data is acquired for each of the test pattern and the reference pattern. However, the actual image data is distorted compared to the image data when read ideally due to the influence of the reading position error. Therefore, when analyzing the image data, the correction value acquisition program cancels the influence of the reading position error on the image data of the test pattern based on the image data of the reference pattern.

<< Calculation of correction value >>
Next, the step of calculating the correction value by analyzing the image data of the test pattern will be described with reference to FIG. FIG. 13 is a flowchart of steps for calculating a correction value.

<Preparation process>
As shown in FIG. 13, as a preparation for calculating a correction value, a preparation process for analyzing image data of a test pattern and a reference pattern acquired from the scanner 150 is performed (S121). The preparation process is executed by a correction value acquisition program. As the preparatory process, first, a process for correcting the inclination generated when each of the test sheet TS and the reference sheet SS is inclined and set on the scanner 150 is performed on each image data of the test sheet TS and the reference sheet SS. . In correcting the inclination, the inclination angle is detected by a known detection method for each image of the test pattern and the reference pattern. Then, based on the tilt angle, each image is rotated to correct the tilt of each image. The rotation process is performed individually for each of the test pattern and the reference pattern. As a result of performing such individual rotation processing, the position of the test pattern with respect to the reference pattern may be relatively shifted. In consideration of such a case, the deviation caused by the individual rotation processing is evaluated, and when the position of each pattern is calculated in the step of calculating the position of each pattern (S122), the deviation is subtracted from the position.

  Further, distortion of the test pattern itself is detected as the next preparation process. The distortion of the test pattern itself is distortion generated when the test sheet TS is tilted during printing of the test pattern. For example, if the paper width direction of the test sheet TS is inclined with respect to the scanning direction of the head 41 during printing of the test pattern, the test pattern is printed in a distorted state with respect to the test sheet TS. When the distortion of the test pattern itself becomes significant, an inappropriate value is obtained when the correction value is calculated based on the test pattern. In order to avoid such a situation, the distortion of the test pattern itself is evaluated, and if the distortion is more than a specified distortion, an error is determined.

<Calculation of pattern position>
After performing the above preparation processing, the position of each line of the reference pattern and the position of each pattern of the test pattern are calculated in the scanner coordinate system by the correction value acquisition program (S122). In the scanner coordinate system, an image acquired by reading by the scanner 150 is assumed to be composed of 1/720 × 1/720 inch pixels. Further, the position of the upper left pixel in each image is set as the origin of the scanner coordinate system. Thereafter, the correction value acquisition program calculates the formation position of each pattern on the test sheet TS, that is, the absolute position of each pattern, based on the position of each line and the position of each pattern in the scanner coordinate system ( S123).

  Hereinafter, a description will be given with reference to FIGS. 14A and 14B, FIG. 15 and FIG. FIG. 14A is a diagram illustrating a range used when calculating the position of each pattern in the scanner coordinate system in the test pattern image. FIG. 14B is an explanatory diagram for calculating the position of the pattern. The horizontal axis indicates the position of the pixel in the y direction (scanner coordinate system). The vertical axis indicates the gradation value of the pixel (the average value of the gradation values of the pixels arranged in the x direction). FIG. 15 is an explanatory diagram of the calculated pattern positions, and the positions shown in the figure are made dimensionless by performing a predetermined calculation. FIG. 16 is an explanatory diagram regarding the calculation of the absolute position of the i-th pattern of the test pattern. Here, the i-th pattern of the test pattern is a pattern located between the j-1th line of the reference pattern and the j-th line of the reference pattern.

  In the following description, the position of the i-th pattern (scanner coordinate system) of the test pattern is called “M (i)”, and the position of the j-th line (scanner coordinate system) of the reference pattern is “K (j ) ". The interval between the j−1th line and the jth line of the reference pattern (interval in the y direction) is called “L”, and the j−1th line of the reference pattern and the ith pattern of the test pattern Is referred to as “L (i)”.

  First, the correction value acquisition program calculates the position of each pattern using image data of an image in a range indicated by a dotted line in the test pattern image shown in FIG. 14A. Here, the correction value acquisition program calculates the centroid position of the gradation value for each pattern from the image data of the image in the range indicated by the dotted line (see FIG. 14B), and uses this centroid position as the position of each pattern. .

Next, when calculating the absolute position, the correction value acquisition program calculates the ratio H of the interval L (i) to the interval L based on the following equation.
H = L (i) / L
= {M (i) -K (j-1)} / {K (j) -K (j-1)}

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

  Hereinafter, the procedure for calculating the absolute position of each pattern will be described with reference to a case where the absolute position R (1) of the first pattern in the test pattern is calculated. First, as shown in FIG. 15, according to the correction value acquisition program, the position M (1) of the pattern P (1) is changed to the position K (2) of the second line and the position K (3 of the third line of the reference pattern. ) Is detected. Next, the correction value acquisition program determines that the ratio H is 0.40143008 (= (373.7686667-309.613250) / (469.430413-309.613250)). Finally, the absolute position R (1) of the first pattern is required to be 0.98878678 mm (= 0.038928613 inches {= 1/36 inch} × 0.40143008 + 1/36 inches) from the positional relationship shown in FIG. .

<Acquisition of correction value>
Next, the correction value is calculated from the absolute position of each pattern by the correction value acquisition program (S124).

  More specifically, the correction value C (i) is calculated based on the absolute position R (i) of the i-th pattern in the test pattern and the absolute position R (i + 1) of the i + 1-th pattern. This correction value C (i) is determined by the transport operation performed between pass i and pass i + 1 during the second test pattern printing (more precisely, the test sheet TS is transported between pass i and pass i + 1). Theoretical movement section moving in the direction). The correction value C (i) is obtained as a difference between the theoretical pattern interval and the actual pattern interval of the patterns P (i) and P (i + 1).

  Here, when i is 1 to m−2, the correction value C (i) is obtained by subtracting “R (i + 1) −R (i)” from “3.18 mm” (1/8 inch). Become. For example, the correction value C (1) is obtained for the transport operation between pass 1 and pass 2, and the value is 3.18 mm- {R (2) -R (1)}. In this way, correction values from the correction value C (1) to the correction value C (m−2) are calculated for each transport operation as shown in FIG. FIG. 17 is an explanatory diagram of correction values calculated for each transport operation.

  Similarly, a correction value Ck is calculated as a correction value for the transport operation between pass m and pass m + 1. The correction value Ck is obtained as a difference between the theoretical pattern interval of the patterns P (m) and P (m + 1) and the actual pattern interval, and the value is from “4.23 mm” (1/6 inch). A value obtained by subtracting “R (m + 1) −R (m)”. Further, as described above, kicking occurs between the path m and the path m + 1 (in other words, the test sheet TS passes through the actually measured kicking position), so the correction value Ck corrects the conveyance error due to kicking. It can be said that this is a correction value for this.

  Further, a correction value Cb is calculated as a correction value for the transport operation between pass m + 1 and pass m + 2. The correction value Cb is obtained as a difference between the theoretical pattern interval and the actual pattern interval of the patterns P (m + 1) and P (m + 2), and the value is calculated from “0.847 mm” (3/90 inch). A value obtained by subtracting “R (m + 2) −R (m + 1)”.

<Averaging correction values>
By the way, there is a possibility that the rotational position of the paper feed roller 23a at the start of each transport operation differs between printing processes. As a result, the pattern interval in the patterns P (1) to P (m−1) is affected not only by the DC component transport error but also by the AC component transport error. However, the correction values C (1) to C (m−2) obtained by the above method do not consider the influence of the AC component transport error. For this reason, if the correction values C (1) to C (m−2) are applied as they are, there is a possibility that the conveyance error is worsened.

Therefore, in the present embodiment, the correction values C (1) to C (m−2) are averaged by the following equation in order to make it difficult to reflect the influence of the AC component transport error (S125). A correction value obtained by averaging is referred to as an average correction value Ct.
Ct (i) = {C (i-3) + C (i-2) + C (i-1) + C (i) + C (i + 1) + C (i + 2) + C (i + 3) + C (i + 4)} / 8

  Hereinafter, the relationship between each pattern in the test pattern and the average correction value Ct will be described with reference to FIG. FIG. 18 is an explanatory diagram of the relationship.

  As shown in FIG. 18, the average correction value Ct (i) is obtained based on each pattern interval in the patterns P (i-3) to P (i + 4). For example, the average correction value Ct (4) is a value obtained by dividing the sum of the correction values C (1) to C (8) by 8 (an average value of the correction values C (1) to C (8)). The average correction value Ct (i) obtained in this way is obtained for the transport operation between pass i and pass i + 1 in the second test pattern printing. That is, the average correction value Ct (i) is calculated for the movement section (theoretical value) in which the test sheet TS moves in the conveyance operation between pass i and pass i + 1.

  When i is 3 or less when calculating the average correction value Ct (i), the average correction value Ct (i) is obtained by dividing the sum of C (1) to C (8) by 8. To do. Further, when i is m−5 or more when calculating the average correction value Ct (i), the average correction value Ct (i) is the sum of C (m−9) to C (m−2). The value divided by 8 is used. In addition, the average correction value Ct (m−1) for the transport operation (m-th transport operation) between the pass m−1 and the pass m is the transport operation between the pass m−2 and the pass m−1 ( The average correction value Ct (m−2) for the (m−1) th transport operation) is set to the transport direction length a of the travel section of the test sheet TS in the mth transport operation and the travel section in the (m−1) th transport operation. A value obtained by multiplying the ratio a / b with the length b in the transport direction.

  Incidentally, since the patterns P (1) to P (m−1) are formed approximately every 1/8 inch, the average correction value Ct is calculated every 1/8 inch. That is, since the pattern interval is set to be 1/8 of the circumferential length (1 inch) of the paper feed roller 23a in the second test pattern printing, each average correction value Ct (i) should be theoretically separated by 1 inch. Despite the value corresponding to the interval between the two patterns, the applicable range can be reduced to 1/8 inch. As a result, it becomes difficult to be influenced by the AC component transport error, and the DC component transport error can be finely corrected.

  The correction value Ck is a correction value for correcting a conveyance error due to kicking, and is not suitable for averaging together with other correction values. For this reason, in the present embodiment, the correction value Ck is not a target for averaging. Further, the correction value Cb is not suitable for averaging together with other correction values, and therefore is not subjected to averaging.

<< Storage of correction values >>
Next, the step (S114) of storing the correction value in the memory 63 of the printer 1 by the correction value acquisition program will be described.

  The correction values stored in the memory 63 are an average correction value Ct (i), a correction value Ck, and a correction value Cb. Further, boundary position information for indicating a range (application range) to which each correction value is applied is also stored in the memory 63. The boundary position information is information indicating both boundary positions on the upper end side in the transport direction and the lower end side in the transport direction of the application range of each correction value. The correction value and the boundary position information are stored as a table as shown in FIG. FIG. 19 is a diagram showing correction values and boundary position information stored in the memory 63. That is, in this embodiment, each correction value is stored in the memory 63 in association with the application range of each correction value. As shown in FIG. 19, the application range of the correction value Ck is from the theoretical position when the pattern P (m) is formed (that is, the theoretical position in the path m) to the theoretical position when the pattern P (m + 1) is formed (that is, The range up to (theoretical position in path m + 1). Since the range corresponds to the above-described kick generation range, the correction value Ck is stored in the memory 63 in association with the kick generation range.

=== Moving section determination processing ===
Next, the above-described movement section determination process will be described with reference to FIG. FIG. 20 is a flowchart of the movement section determination process.

  The movement section determination process is a transport operation in which the paper is transported so as to pass through the actually measured kicking position (hereinafter referred to as a transporting operation in which kicking occurs) among the transporting operations during the main printing performed by the user. This is a process of determining the target movement section of the paper so that the relative positional relationship between the target movement section and the actually measured kicking occurrence position is a predetermined positional relationship. Here, the target moving section is a theoretical moving section in which the paper moves in the transport direction when the transport operation is executed. More specifically, a section from the theoretical position in one pass to the theoretical position in the next pass during the main printing corresponds to the target movement section.

  Since the movement section determination process is performed based on the actually measured kicking occurrence position, the above-described measurement process is performed in advance of the movement section determination process. In addition, as shown in FIG. 20, in the movement section determination process, a step (S131) for specifying a conveyance operation in which kicking occurs based on the actually measured kicking occurrence position is determined, and a target movement section in the conveyance operation in which the kicking occurs is determined. It consists of a step (S132) and a step (S133) for updating information indicating the target conveyance amount before correction in the first conveyance operation. Each step is performed between the end of the correction value acquisition process and the shipment of the printer 1. The movement section determination process is performed by a movement section determination program installed in advance in the computer 110 in a state where the printer 1 and the computer 110 in the factory are connected.

<Conveying operation in actual printing>
Before describing each step of the movement section determination process, the transport operation in the main printing will be described with reference to FIGS. 21 and 22. FIG. 21 is an explanatory diagram of information related to the transport operation in the main printing. FIG. 22 is a diagram illustrating a state of the main printing. The right side of the drawing shows the paper on which the image is printed, and the rectangle shown on the left side of the drawing shows the position of the head 41 in each pass during the actual printing. As in FIG. 7, FIG. 22 is drawn as if the head 41 is moving with respect to the paper for the sake of illustration, but this figure shows the relative position of the paper with respect to the head 41. Further, in the head 41 shown in the drawing, a region filled with gray indicates a region where nozzles that do not eject ink are arranged in each pass. In the following description, the theoretical position of the paper in pass i during the actual printing is called a theoretical position Q (i).

  In performing the transport operation in the main printing, the controller 60 reads information (hereinafter referred to as recording information) related to the transport operation stored in advance in the memory 63 and executes the transport operation based on the record information. As shown in FIG. 21, the recording information includes information on a target transport amount before correction for transporting paper in a transport operation performed between passes. It should be noted that the period after the assembly of the printer 1 is completed until the movement section determination process is performed (more precisely, before the information on the target conveyance amount before correction is updated by the movement section determination process). A temporary determination value of the target conveyance amount before correction is stored in the memory 63 as information on the target conveyance amount.

  Here, the target conveyance amount before correction for conveying the paper in the conveyance operation between pass i-1 and pass i is F (i). If the actual printing is performed based on the provisional predetermined value of the target carry amount F (i) before correction, the theoretical position Q (i) of the paper in each pass is as shown in FIG. Of the target transport amount F (i) before correction, F (1) is the target transport amount before correction for positioning the paper at the cueing position in the first transport operation. As described above, the main printing includes borderless printing and bordered printing. Since the cueing position differs between these prints, the information on the target carry amount F (1) before correction is stored in the memory 63 separately for borderless printing and bordered printing.

Hereinafter, the target transport amount before correction will be described in more detail with reference to FIGS. 21 and 22.
When each transport operation is ideally executed without any transport error, the paper is transported by the target transport amount before correction in each transport operation. For example, when the transport operation between pass i-1 and pass i (i-th transport operation) is ideally performed, the paper is transported downstream in the transport direction by the target transport amount F (i) before correction. The When the i-th transport operation is completed, the paper is positioned at the theoretical position Q (i) in pass i. Further, the theoretical position Q (i) is theoretically separated downstream in the transport direction by a distance corresponding to the sum from the cueing position (that is, the theoretical position Q (1)) to F (2) to F (i). It becomes the position.

  As shown in FIG. 21, the pre-correction target transport amount F (i) in the transport operation executed between pass 1 to pass 4 among the pre-correction target transport amount F (i) is the above-described upper end printing. This is the target conveyance amount before correction in the middle conveyance operation. Similarly, the pre-correction target transport amount F (i) in the transport operation executed between pass 5 and pass n is the pre-correction target transport amount in the transport operation during normal printing, and between pass n + 1 to pass n + 4. The pre-correction target carry amount in the carry operation executed in the above is the pre-correction target carry amount in the carry operation during the lower end printing. Further, the target transport amount before correction in the transport operation during normal printing is different from the target transport amount in the transport operation during the second test pattern printing. In this embodiment, the target conveyance amount before correction in the conveyance operation during normal printing is set to be larger than 1/6 inch (that is, the theoretical conveyance direction length of the kicking occurrence range).

<Determination of target travel section>
Next, each step of the movement section determination process will be specifically described with reference to FIGS. FIG. 23 is an explanatory diagram of the procedure for determining the target movement section, and corresponds to FIG.

  In the movement section determination process, first, assuming that the actual printing is performed based on the provisionally determined value of the pre-correction target conveyance amount F (i), the conveyance in which kicking occurs in the conveyance operation during the actual printing. Identify the behavior. In the case shown in FIG. 22, in the actual printing performed based on the provisional predetermined value of the target conveyance amount F (i) before correction, the conveyance operation (n-th time) executed between pass n-1 and pass n. The transport operation) is specified as the transport operation in which kicking occurs.

  Next, the target movement section (that is, the section from the theoretical position Q (n−1) to the theoretical position Q (n)) in which the paper moves in the n-th transport operation is determined again. As a result, the target movement section in the conveying operation in which kicking occurs is determined such that the relative positional relationship between the target movement section and the actually measured kicking occurrence position is a predetermined positional relationship. Hereinafter, taking the above case (that is, a case where the transport operation in which kicking occurs as the n-th transport operation) as a specific example, a procedure for determining the target movement section of the paper in the transport operation in which kicking occurs will be described in detail. .

  As described above, if the actual printing is performed based on the provisional predetermined value of the pre-correction target transport amount F (i), the paper passes through the kicking occurrence position measured in the n-th transport operation. On the other hand, as shown in FIG. 22, when the main printing is performed based on the tentative value of the target transport amount F (i) before correction, the center in the transport direction of the target movement section of the paper in the nth transport operation. The position and the actually measured kicking occurrence position are shifted by a distance Δ in the transport direction.

  In such a situation, the target movement section is determined again so that the center position in the conveyance direction of the target movement section in the conveyance operation in which kicking occurs and the actually measured kicking occurrence position coincide with each other. In this embodiment, in order to re-determine the target movement section, the cue position, that is, the pre-correction target transport amount F (1) in the first transport operation is adjusted. This is because the theoretical position Q (i) in each path is determined depending on the cue position, so that adjusting the cue position also determines the target movement section in the nth transport operation (the transport operation in which kicking occurs). It is to be done.

  More specifically, in the case shown in FIG. 22, the pre-correction target transport amount F (1) in the first transport operation is adjusted to a transport amount that is smaller by the distance Δ. As a result, the cue position is positioned upstream by Δ from the initial cue position. Accordingly, the target movement section in the n-th transport operation is positioned upstream by Δ from the original target movement section. As a result, as shown in FIG. 23, the relative positional relationship between the target movement section in the n-th transport operation and the actually measured kicking occurrence position is such that the center position in the conveyance direction of the target movement section and the actually measured kicking occurrence position are The positional relationship is such that That is, the target movement section in the n-th transport operation is determined anew so that the relative positional relationship is the above positional relationship.

  Further, in the present embodiment, as shown in FIG. 23, as a result of re-determining the target movement section in the n-th transport operation, the target movement section is applied to the application range of the correction value Ck, that is, the section straddling the kicking occurrence range. Become. In other words, the application range of the correction value Ck is included in the target movement section in the n-th transport operation. This is because the conveyance direction length of the target movement section in the n-th conveyance operation, that is, the pre-correction target conveyance amount F (n) is set to be larger than the conveyance direction length of the kicking occurrence range. . Under this setting, if the center position in the transport direction of the target movement section in the n-th transport operation matches the center position in the transport direction of the kick generation range (that is, the measured kick generation position), the target movement section Will always straddle the kicking range.

  When the target movement section in the n-th transport operation is determined as described above, the information related to the pre-correction target transport amount F (1) in the first transport operation stored in the memory 63 is the adjusted F (1). It is updated to information indicating. When the update is completed, the movement section determination process is completed, and then the printer 1 is packed and shipped.

  In the present embodiment, the cue position is adjusted to determine the target movement section in the n-th transport operation, but the present invention is not limited to this. As another method for determining the target movement section in the n-th transport operation, one of the theoretical positions Q (i) from pass 2 to pass n−1, in other words, the target transport amount before correction F (2) ˜ A method of adjusting any one of F (n-1) is also conceivable. However, the theoretical position Q (1), which is the cueing position, can be adjusted more easily in terms of control compared to the theoretical position Q (i) after pass 2. In this respect, the present embodiment is more advantageous.

  However, there is a limit to the adjustment of the cue position. More specifically, when performing borderless printing, the cueing position must be adjusted so that the leading edge of the paper reaches the ink accumulation groove forming position at the start of borderless printing. In addition, when performing printing with margins, the cueing position must be adjusted so that printing is performed with a margin of a predetermined size provided at the end in the paper conveyance direction. On the other hand, when adjusting the cue position in order to determine the target movement section in the conveyance operation in which kicking occurs, if the adjustment amount (that is, the distance Δ) becomes large, the above requirement may not be satisfied. There is also. In such a case, instead of adjusting the cueing position, as shown in FIG. 24, any one of the pre-correction target transport amounts F (2) to F (n-1) is adjusted. FIG. 24 shows an example of adjusting the pre-correction target transport amount F (5) in the transport operation between the pass 4 and the pass 5 as another method for determining the target movement section in the transport operation in which kicking occurs. It is a figure.

=== Conveying operation during actual printing under the user ===
When the main printing is performed by the user who purchased the printer 1, the controller 60 reads the recording information and the correction value recorded in the memory 63, and the target conveyance amount F (i) before correction in the recording information. Is corrected by the correction value, and a transport operation is executed based on the corrected target transport amount (corrected target transport amount). Hereinafter, application of the correction value to each transport operation will be described.

 For example, when a target movement section in which a sheet moves in a certain transport operation overlaps a certain correction value application range, the certain correction value is applied to the certain transport operation. That is, for a transport operation for transporting paper from a position located upstream of the downstream boundary position of the application range of a certain correction value to a position positioned downstream of the upstream boundary position of the application range, A certain correction value is applied. In the following description, application examples of correction values will be described for each type of correction value (average correction value Ct, correction value Ck, and correction value Cb).

<Correction by average correction value Ct>
First, the correction using the average correction value Ct (i) will be specifically described.
As shown in FIG. 19, the application range of the average correction value Ct (i) corresponds to the range from the theoretical position at the time of forming the pattern P (i) to the theoretical position at the time of forming the pattern P (i + 1). For example, the application range of the average correction value Ct (3) corresponds to the range from the theoretical position when the pattern P (3) is formed to the theoretical position when the pattern P (4) is formed. Then, the target movement section of the paper in the transport operation between pass j-1 and pass j during the actual printing (the target movement section in the j-th transport operation, which is the theoretical position Q (j-1) to the theoretical position). When the Q (j) section) overlaps the application range of the average correction value Ct (i), the average correction value Ct (i) is applied to the j-th transport operation. Hereinafter, an application example of the average correction value Ct (i) will be specifically described with reference to FIGS. 25A to 25D. 25A to 25D are explanatory diagrams of application examples of the average correction value Ct (i).

  As shown in FIG. 25A, the first example of application of the average correction value Ct (i) is that the theoretical position Q (j-1) in the path j-1 is the upstream boundary position of the application range of the correction value Ct (i). And the theoretical position Q (j) in the path j matches the downstream boundary position of the application range. In this case, the controller 60 corrects the pre-correction target transport amount F (j) in the j-th transport operation using the average correction value Ct (i).

  As shown in FIG. 25B, the second example of application of the average correction value Ct (i) is that the theoretical position Q (j−1) and the theoretical position Q (j) are both within the application range of the correction value Ct (i). This is the case inside. In this case, the controller 60 sets the ratio F (j) / L between the target conveyance amount F (j) before correction and the conveyance direction length L of the application range of the average correction value Ct (i) to Ct (i). The multiplied value is used as a correction value. Then, the controller 60 corrects the pre-correction target transport amount F (j) with the correction value.

  As shown in FIG. 25C, the third example of application of the average correction value Ct (i) is that the theoretical position Q (j−1) is within the application range of the average correction value Ct (i) and the theoretical position Q This is a case where (j) is within the application range of the average correction value Ct (i + 1). That is, this is a case where the target movement section in the j-th transport operation covers the application range of two average correction values Ct (i) and Ct (i + 1). Here, among the uncorrected target transport amount F (j), the transport amount within the application range of the average correction value Ct (i) is Fx, and the transport amount within the application range of the average correction value Ct (i + 1) is Let it be Fy. In addition, the conveyance direction length of the application range of the average correction value Ct (i) is Lx, and the conveyance direction length of the application range of the average correction value Ct (i + 1) is Ly. In this case, the controller 60 uses the sum of the value obtained by multiplying Ct (i) by Fx / Lx and the value obtained by multiplying Ct (i + 1) by Fy / Ly as the correction value. Then, the controller 60 corrects the pre-correction target transport amount F (j) with the correction value.

  As shown in FIG. 25D, the fourth example of application of the average correction value Ct (i) is that the theoretical position Q (j−1) is within the application range of the average correction value Ct (i−1), and the path j This is a case where the theoretical position Q (j) is within the application range of the average correction value Ct (i + 1). That is, this is a case where the target movement section in the j-th transport operation covers the application range of the three average correction values Ct (i−1), Ct (i), and Ct (i + 1). Here, among the uncorrected target transport amount F (j), the transport amount within the application range of the average correction value Ct (i−1) is Fx, and the transport amount at the average correction value Ct (i + 1) is Fy. To do. In addition, the conveyance direction length of the application range of the average correction value Ct (i−1) is Lx, and the conveyance direction length of the application range of the average correction value Ct (i + 1) is Ly. In this case, the controller 60 uses the sum of a value obtained by multiplying Ct (i−1) by Fx / Lx, a value obtained by multiplying Ct (i) and Ct (i + 1) by Fy / Ly as a correction value. . Then, the controller 60 corrects the pre-correction target transport amount F (j) with the correction value.

  As described above, the controller 60 corrects the pre-correction target transport amount F (j) with the average correction value Ct (i) and corrects the pre-correction target transport amount F (j) based on the corrected target transport amount. The j-th transport operation is executed. As a result, the aforementioned DC component transport error is corrected. In addition, since the application range of each average correction value Ct (i) is set every 1/8 inch, the DC component transport error that changes according to the relative position between the paper and the head 41 can be corrected accurately. Can do.

<Correction with correction value Ck>
Next, correction using the correction value Ck will be described.
As shown in FIG. 19, the application range of the correction value Ck is a range from a theoretical position at the time of forming the pattern P (m) to a theoretical position at the time of forming the pattern P (m + 1). When the target movement section in a certain transport operation during the actual printing has an overlap with the application range of the correction value Ck, the correction value Ck is applied to the certain transport operation.

  In the present embodiment, since the target movement section in the n-th transport operation is determined to be a section across the application range of the correction value Ck by the movement section determination process (see FIG. 23), the n-th transport is performed. The correction value Ck is applied to the operation. Further, since the target movement section in the n-th transport operation straddles the application range of the correction value Ck, the correction value Ck is obtained by the same procedure as the fourth example of the application examples of the average correction value Ct (i) described above. Applied. That is, the controller 60 uses the values calculated using Ct (i), Ck, and Cb as correction values, and corrects the pre-correction target transport amount F (n) in the n-th transport operation using the correction values. To do.

  In this way, the controller 60 performs the nth time based on the corrected target transport amount corrected by the correction value Ck (more precisely, the correction value calculated using Ct (i), Ck, and Cb). By performing the transport operation, it becomes possible to correct the transport error due to kicking and transport the paper appropriately.

  Furthermore, as shown in FIG. 23, the target movement section that overlaps the application range of the correction value Ck is only the target movement section in the n-th transport operation. For this reason, the transport operation to which the correction value Ck is applied is limited to the n-th transport operation. In addition, as described above, the application range of the correction value Ck corresponds to the kicking occurrence range, and the kicking occurrence range includes the actually measured kicking occurrence position and is a range that takes into account the deviation of the kicking occurrence position. ing. Accordingly, the kicking is surely generated while the paper is moving in the target movement section across the application range of the correction value Ck (that is, when the n-th transport operation is performed) unless an unexpected disturbance or the like occurs. It will be. As a result, it is avoided that the correction value Ck is applied to a transport operation in which kicking does not occur (a transport operation other than the n-th transport operation and the correction value Ck should not be applied). Is possible.

<Correction with correction value Cb>
Next, correction using the correction value Cb will be described.
As shown in FIG. 19, the application range of the correction value Cb is a range during the conveyance of the paper from the theoretical position to the downstream side in the conveyance direction when the pattern P (m + 1) is formed. That is, the correction value Cb is applied to a transport operation that is executed when the paper is in the non-nip state during the actual printing. The transport operation executed when the paper state is in the non-nipping state is the nth to n + 4th transport operation.

  When the controller 60 executes the n + 1 to n + 4th transport operations, the controller 60 corrects the pre-correction target transport amounts F (n + 1) to F (n + 4) with the correction value Cb, and based on the corrected post-correction target transport amount. To execute the transfer operation. In this way, by performing the n + 1 to n + 4th transport operations based on the post-correction transport amount corrected by the correction value Cb by the controller 60, the transport error that occurs in the n + 1 to n + 4th transport operations can be accurately corrected. Is possible. Since the n-th transport operation is as described above, the description thereof is omitted.

=== Effectiveness of the Moving Section Determination Method of the Present Embodiment ===
In the present embodiment, the kicking occurrence position is actually measured, and in the carrying operation during the actual printing, the paper is carried so that the paper passes through the actually measured kicking occurrence position (that is, the carrying operation in which kicking occurs). The target movement section is determined such that the relative positional relationship between the target movement section and the actually measured kicking occurrence position is a predetermined positional relationship. Hereinafter, the effectiveness of the moving section determination method of the present embodiment will be described in more detail.

  Regarding the relative positional relationship between the target movement section in the transport operation in which kicking occurs and the kicking occurrence position, for various reasons, the positional relationship in which the central position in the conveyance direction of the target movement section and the kicking generation position coincide with each other. It is desirable that

  The reason for this is, for example, that the correction value Ck is avoided from being applied to a transport operation in which the correction value Ck for correcting the transport error due to kicking should not be applied. More specifically, in order to avoid the correction value Ck being applied to the transport operation to which the correction value Ck should not be applied, the correction value Ck is within the target movement section in the transport operation in which kicking occurs. Must be included, that is, the kicking occurrence range should be included. If the center position in the transport direction of the target movement section matches the center position in the transport direction of the kick generation range, that is, the kick generation position, the kick generation range is most efficiently included in the target movement section. Is possible.

  Another reason is that, for example, the kicking is generated in a state in which the moving speed of the paper is stable in the conveying operation in which the kicking occurs. More specifically, in the present embodiment, the paper moving speed is accelerated (decelerated) immediately after the start of each transport operation (immediately before the end), whereas the paper is transported in the target movement section in each transport operation. When passing through the central position, the moving speed becomes substantially constant. On the other hand, if kicking occurs while the paper moving speed is accelerated (decelerated), there is a possibility that the conveyance error due to kicking will be affected and the correction effect due to the correction value Ck may not be properly exhibited. On the other hand, if the center position in the transport direction of the target movement section in the transport operation in which kicking occurs is coincident with the kick generation position, it is possible to generate kicking in a state where the moving speed is substantially constant. Thus, the correction effect by the correction value Ck is also exhibited appropriately.

  For the reasons described above, the relative positional relationship is determined so as to be a positional relationship in which the center position in the transport direction of the target movement section where kicking occurs and the kicking occurrence position coincide with each other. And in determining the relative positional relationship, it is necessary to specify the kicking position. Conventionally, the kicking position has been specified by prediction based on experience or the like. However, as explained in the section “Problems to be Solved by the Invention”, the actual kicking occurrence position may be different from the predicted kicking occurrence position. For this reason, when the target movement section in the conveyance operation in which kicking occurs is determined based on the predicted kick occurrence position, when the actual printing is actually performed, the center position in the conveyance direction of the target movement section and the actual kick generation occur. The position may be shifted.

  On the other hand, in the present embodiment, the target movement section in the conveying operation in which kicking occurs is determined based on the actually measured kicking occurrence position. As a result, when the actual printing is performed, the relative positional relationship between the target movement section in the conveying operation in which kicking occurs and the actual kicking occurrence position is almost certainly the above positional relationship. That is, the center position in the transport direction of the target movement section substantially coincides with the actual kicking occurrence position. Accordingly, for example, the correction value Ck is avoided from being applied to a transport operation to which the correction value Ck should not be applied, and the kicking is generated with the paper moving speed being substantially constant. Is also possible. As a result, it is possible to appropriately transport the medium in consideration of a transport error due to kicking.

=== Method for Determining Movement Section for Plural Types of Paper ===
In the above-described embodiment, a method has been described in which the kicking occurrence position is actually measured for one piece of paper, and the target movement section in the conveying operation in which kicking occurs is determined based on the kicking occurrence position.

  On the other hand, the printer 1 may print images on a plurality of different types of paper. When the type of paper on which the image is printed (particularly, the paper size) is different, the kicking occurrence position is different. For this reason, when there are a plurality of types of paper on which an image can be printed by the printer 1, an example (another example) in which the target movement section in the transport operation in which kicking occurs is determined for each paper type is also conceivable. Other examples will be described below.

  First, in the actual measurement process, the kicking occurrence position is actually measured for each paper type according to the procedure described above. That is, in the present embodiment, the actual measurement process for actually measuring the occurrence position of kicking from the first test pattern by printing the first test pattern on each paper (more precisely, the same type of test sheet TS as each paper) is performed. Implement each type individually.

  Next, in the correction value acquisition process, the correction value is calculated for each type according to the procedure described above. In this embodiment, the correction value table shown in FIG. 19 is created for each type and stored in the memory 63 in association with the type.

  Next, based on the kicking occurrence position measured for each paper type, a target movement section in the transport operation in which kicking occurs is determined for each type. In the present embodiment, there are two methods for determining the target movement section by type.

  The first method for determining the target movement section for each paper type is to determine the target movement section for each paper type in the transport operation in which kicking occurs by the same procedure as the target movement section determination procedure described above. It is a method to do. More specifically, first, in the transport operation when the actual printing is performed based on the provisional predetermined value of the target transport amount before correction, a certain paper is caused to pass the kick occurrence position measured for the certain paper. A transport operation (hereinafter referred to as a transport operation in which kicking occurs for a certain sheet of paper) is specified. Next, the relative movement between the target movement section and the kicking occurrence position actually measured for the certain paper is determined as the target movement section in the conveyance operation in which kicking occurs for the certain paper, The determination is made again so that the positional relationship is matched with the actually measured kicking position for a certain paper. At this time, the target movement section is determined by adjusting the cueing position in the main printing, that is, the pre-correction target transport amount F (1) in the first transport operation. Hereinafter, the same procedure is carried out for other paper different in type from the certain paper. Then, information indicating the pre-correction target carry amount F (1) adjusted for each paper type is stored in the memory 63 in association with the information indicating the paper type. In other words, the memory 63 stores information indicating the pre-correction target carry amount F (1) for the type of paper.

  As described above, in the first method, the cueing position in the main printing is adjusted for each type of paper, and the target movement section in the transport operation in which kicking occurs is determined for each type. Accordingly, it is possible to appropriately determine the target movement section in the transport operation in which kicking occurs in consideration of the fact that the occurrence position of kicking differs for each type of paper on which an image is printed by the printer 1.

  The second method of determining the target movement section according to the type of paper is based on the kicking occurrence position measured for two types of media that are different from each other, and a common cueing position between the types (in other words, This is a method of determining the target movement section for each type by adjusting the pre-correction target carry amount F (1)) in the first carry operation common to the types of paper. That is, in the second method, the cueing position is not adjusted individually for each type, but the cueing position is adjusted collectively between the types. Hereinafter, an example of a procedure for adjusting the common cueing position will be described with reference to FIGS. 26, 27A and 27B, and FIGS. 28A and 28B. FIG. 26 is a diagram illustrating kicking positions actually measured for each type of paper and initial target movement sections in a transport operation in which kicking occurs. FIG. 27A and FIG. 27B are diagrams showing a state in which an adjustment amount for a common cue position is obtained. FIG. 28A and FIG. 28B are diagrams illustrating a state in which a common cue position is adjusted to determine a target movement section in a transport operation in which kicking occurs for each paper type.

  Hereinafter, as a specific example, a case will be described in which a common cueing position is adjusted for two sheets A and B having different sizes (lengths in a direction intersecting the sheet width direction).

  In the second method, first, as in the first method, among the transport operations of actual printing that are temporarily performed based on the provisional predetermined value of the target transport amount before correction, the transport operation in which kicking occurs is specified for each paper type. To do. Here, as shown in FIG. 26, the transport operation in which kicking occurs is a transport operation between pass v-1 and pass v (vth transport operation) for paper A, and pass w for paper B. It is assumed that the transfer operation is between -1 and pass w (the w-th transfer operation).

  Further, as shown in FIG. 26, as a result of different transport operations in which kicking occurs due to differences in size, the relative positional relationship between the target movement section in the transport operation and the actually measured kicking occurrence position (provisional determination of the target transport amount before correction) The relative positional relationship when the actual printing is performed based on the value (hereinafter referred to as the initial relative positional relationship) differs depending on the paper type. In the case shown in FIG. 26, for the paper A, the actually measured kicking occurrence position is separated from the central position in the transport direction of the target movement section where the kicking occurs by a distance Δa. For paper B, the measured kicking occurrence position is separated from the central position in the transport direction of the target movement section where kicking occurs by a distance Δb.

  On the other hand, the distances Δa and Δb are adjusted simultaneously by adjusting the common cueing position. However, when the distances Δa and Δb are different from each other, for each of the paper A and the paper B, the measured kick generation position and the center position in the transport direction of the target movement section in the transport operation in which the kick occurs are matched ( In other words, the common cueing position cannot be adjusted (so that the distances Δa and Δb are both 0). Therefore, in such a case, the sum of the adjusted distances Δa and Δb is minimized, and the distances Δa and Δb are equal to each other (that is, the distances Δa and Δb are arithmetic average distances of the distances Δa and Δb). The common cueing position is adjusted.

  In order to adjust the common cueing position, it is necessary to obtain the adjustment amount in consideration of the difference in the initial relative positional relationship due to the difference in paper type. In obtaining the adjustment amount, as shown in FIG. 27A and FIG. 27B, the boundary between one target movement section in the target movement section in the v-th transport operation and the target movement section in the w-th transport operation. The position is virtually matched with the boundary position of the other target movement section. As a method of adjusting the boundary position, a method of matching the upstream boundary position of one target movement section with the downstream boundary position of the other target movement section (see FIG. 27A), and the upstream boundary of one target movement section There is a method of matching the position with the upstream boundary position of the other target movement section (see FIG. 27B).

  By the way, when the boundary position of the target movement section is adjusted by the above method, the distance between the kicking occurrence positions (indicated by the symbol t in FIGS. 27A and 27B) is equal to the sum of the adjusted distances Δa and Δb. Become. In order to minimize the sum, a method of reducing the distance t between the kicking occurrence positions among the above two methods is adopted. Then, by adjusting the boundary position of the target movement section virtually by this method, it is possible to obtain the adjustment amount of the common cue position. In the case shown in FIG. 26, the distance t between the kicking occurrence positions can be made smaller when the boundary position of the target movement section is matched by the method shown in FIG. 27A. An example in which the common cue position adjustment amount is obtained by matching the boundary positions of the target movement sections by the method shown in FIG. 27A will be described.

  As shown in FIG. 28A, the adjustment amount of the common cueing position includes the center position between the kick occurrence positions and the center position in the transport direction of the target movement section in the transport operation in which kick kick occurs (in FIG. 28A, as a specific example, , The center position in the transport direction of the target movement section in the v-th transport operation is indicated) and the distance Δ. Then, by resetting the pre-correction target transport amount F (1) in the first transport operation to a value that is smaller than the provisional value by a value corresponding to the distance Δ, the common cueing position is adjusted. The common cueing position adjusted in this way is, of course, a position where both the paper A and the paper B are positioned during the first transport operation in the main printing. Then, in the actual printing, when each of the paper A and the paper B is positioned at the adjusted cueing position, as shown in FIG. 28B, in the central position between the kicking occurrence positions and in the conveying operation in which the kicking occurs. The center position in the transport direction of the target movement section matches (accurately, the boundary position of the target movement section matches). As a result, the sum of the distances Δa and Δb is minimized, and the distances Δa and Δb are equal to each other. That is, for both the paper A and the paper B, it is possible to determine the target movement section in the conveyance operation in which kicking occurs so that the center position in the conveyance direction of the target movement section is close to the actually measured kicking occurrence position. In this case, as a result of adjusting the common cueing position, as shown in FIG. 28B, the transport operation in which kicking of the paper B occurs shifts from the w-th transport operation to the (w + 1) th transport operation.

  After the adjustment as described above is performed, the information indicating the pre-correction target transport amount F (1) stored in the memory 63 is changed from the information indicating the provisional value to the information indicating the value adjusted by the above method. Updated. In the second method, unlike the first method, information common to the paper types (ie, single information) is stored in the memory 63 as the information indicating the pre-correction target transport amount F (1). Remembered. For this reason, the amount of information stored in the memory 63 is reduced, and the capacity of the memory 63 can be saved.

=== Other Embodiments ===
The above embodiment mainly describes a method of determining a target movement section in a transport operation in which kicking occurs in the transport operation during the printing process (main printing) of the printer 1, but it is easy to understand the present invention. The present invention is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

1 is a block diagram of an overall configuration of a printer 1. FIG. FIG. 2A is a schematic diagram of the overall configuration of the printer 1. FIG. 2B is a cross-sectional view of the overall configuration of the printer 1. It is a figure which shows a nozzle arrangement | sequence. It is a figure which shows an example of the flow of a printing process. It is a figure which shows the conveyance unit 20 including the control mechanism of conveyance operation. It is a flowchart of an actual measurement process. It is a figure which shows the mode of 1st test pattern printing. It is explanatory drawing of the procedure which specifies a kicking generation | occurrence | production position. It is a flowchart of a correction value acquisition process. It is a figure which shows the mode of 2nd test pattern printing. 2 is a schematic diagram illustrating an internal configuration of a scanner 150. FIG. FIG. 12A is a diagram illustrating the reference sheet SS. FIG. 12B is a diagram illustrating a state when the test sheet TS and the reference sheet SS are set on the document table glass 152. It is a flowchart of the step which calculates a correction value. FIG. 14A is an explanatory diagram of a range of an image used when calculating a pattern position. FIG. 14B is an explanatory diagram for calculating the position of the pattern. It is explanatory drawing of the position of the calculated pattern. It is explanatory drawing of calculation of the absolute position of the i-th pattern of a test pattern. It is explanatory drawing about the correction value calculated with respect to each conveyance operation. It is explanatory drawing about the relationship between each pattern in a test pattern, and the average correction value Ct. It is a figure which shows the correction value memorize | stored in the memory 63, and boundary position information. It is a flowchart of a movement area determination process. It is explanatory drawing about the information regarding the conveyance operation in this printing. It is a figure which shows the mode of this printing. It is explanatory drawing about the procedure which determines a target moving area. It is a figure which shows the other example for determining a target moving area. 25A to 25D are explanatory diagrams of application examples of the average correction value Ct (i). It is a figure which shows the kicking position measured according to the kind of paper, and the initial target moving area in the conveyance operation in which kicking occurs. FIG. 27A and FIG. 27B are diagrams showing a state in which an adjustment amount for a common cue position is obtained. FIG. 28A and FIG. 28B are diagrams illustrating a state in which a common cue position is adjusted and a target moving section in a transport operation in which kicking occurs is determined for each paper type.

Explanation of symbols

1 printer, 110 computer, 20 transport unit,
21 paper feed roller, 22 PF motor, 23 upstream transport roller,
23a paper feed roller, 23b driven roller, 24 platen,
25 downstream transport roller, 25a paper discharge roller, 25b driven roller,
30 Carriage unit, 31 Carriage, 32 Carriage motor,
40 head units, 41 heads, 50 detector groups,
51 Linear encoder, 52 Rotary encoder,
53 paper detection sensor, 54 optical sensor, 60 controller,
61 interface, 62 CPU, 63 memory,
64 unit control circuit, 150 scanner, 151 top cover,
152 platen glass, 153 image reading sensor,
154 guide bar, 155 carriage, 156 moving mechanism,
G Document, TS test sheet, SS reference sheet

Claims (5)

When the state of the medium transitions from a state in which the medium is conveyed by both the pair of upstream-side conveyance rollers and the pair of downstream-side conveyance rollers to a state in which the medium is conveyed by only one of the two, Measuring the position in the transport direction of the medium;
Among the transport operations of the liquid discharge process executed by alternately repeating the transport operation in which the medium is transported by at least one of the both and the discharge operation in which the liquid is ejected onto the medium, A transport operation to be transported so as to pass through the measured position;
Determining a target movement section of the medium at a position such that a relative positional relationship between the target movement section and the actually measured position is a predetermined positional relationship;
A moving section determination method characterized by comprising: In the moving section determination method according to claim 1,
In the step of determining the target movement section,
A positioning position when the medium is positioned in the transport direction at the start of the liquid ejection process;
To determine the target movement section so that the relative positional relationship becomes a predetermined positional relation. In the moving section determination method according to claim 2,
In the step of determining the target movement section, the target movement section is
A moving section determining method, wherein the relative position relation is determined so as to be a positional relation in which a center position in the transport direction of the target moving section matches the measured position. A moving section determination method according to any one of claims 2 and 3,
In the step of measuring the position, the position is measured for each type of medium,
In the step of determining the target movement section,
Adjust the positioning position by type,
A method for determining a moving section, wherein the target moving section is determined for each type so that the relative positional relationship is a predetermined positional relationship. It is the movement section determination method of Claim 2, Comprising:
In the step of actually measuring the position, the position is actually measured for two types of media that are different from each other,
In the step of determining the target movement section,
Adjust the common positioning position between the types,
A method for determining a moving section, wherein the target moving section is determined for each type so that the relative positional relationship is a predetermined positional relationship.