JP2012158412A - Image recorder and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect meandering of a web with high precision in an image recorder.SOLUTION: In the image recorder, a first photoelectric area sensor is located in a width direction of the web over a range where a lateral portion edge and a plurality of holes of the web pass, in an output time series 81 indicating a received light amount of a first photoelectric area sensor, a plurality of correction target ranges 84 corresponding to the plurality of holes of the web are extracted, and a light amount output of each of the correction target ranges 84 is corrected on the basis of a light amount output of an adjacent correction unnecessary range 85. Then, an amount of meandering of the web is calculated on the basis of a difference between the corrected output and a reference output. By this means, even in a portion where a hole is located at the lateral portion of the web, it is possible to calculate the amount of meandering of the web with high accuracy. As a result, it is possible to detect the meandering of the web with high accuracy over an entire range in a longitudinal direction and correct the meandering of the web with high accuracy by a meandering correcting section.

Description

  The present invention relates to an image recording apparatus and an image recording method for recording an image on a long sheet-like web.

  2. Description of the Related Art Conventionally, in an image recording apparatus that records an image on a long sheet-like web, meandering in which the position of the web conveyed in a predetermined conveyance direction is shifted in the width direction may occur. In Patent Document 1, in a printer device that prints on continuous form paper having no sprocket holes, the displacement detection sensor detects the amount of displacement in the width direction of the continuous form paper, and corrects the timing of image recording according to the amount of displacement. Thus, a technique for avoiding deterioration in image quality due to meandering is disclosed. The displacement detection sensor is a photo detector that is placed near the side edge of the continuous form paper, irradiates the light near the side edge of the continuous form paper from the light projecting part, and receives the reflected light from the continuous form paper The light is received by the unit. Then, based on the amount of light received by the light receiving unit, the displacement in the width direction of the continuous form sheet is obtained.

  Patent Document 2 discloses a technique for detecting a sheet end position of a printing sheet having a sheet feed hole in an electrophotographic apparatus. In the electrophotographic apparatus, the printing paper passes between the light source and the light receiving sensor while blocking a part of the light receiving surface of the light receiving sensor. The paper edge position of the printing paper is obtained based on the output from the light receiving sensor, but if the printing paper snakes and the paper feed hole passes over the light receiving surface of the light receiving sensor, the output from the light receiving sensor becomes large. Therefore, in Patent Document 2, the diameter of the paper feed hole is R, the distance between adjacent paper feed holes is L, and the number of samplings of the light receiving sensor at the distance L is N, and the output is large among the N sampling data (N × R / L) sampling data is excluded, and the paper edge position of the printing paper is obtained based only on the remaining sampling data.

JP 2007-91347 A JP 2003-114556 A

  By the way, the printer device of Patent Document 1 cannot accurately detect meandering of printing paper having a paper feed hole provided in the side portion. In the electrophotographic apparatus disclosed in Patent Document 2, the sheet edge position cannot be detected at the position corresponding to the excluded sampling data. Further, in Patent Document 2, sampling data having a large output is excluded on the assumption that the output from the light receiving sensor is maximized in a state where the light receiving sensor and the paper feed hole are overlapped, but the meandering of the printing paper is large, When the light receiving sensor protrudes greatly from the paper edge of the printing paper, the output may be larger than the state where the light receiving sensor overlaps the paper feed hole. In this case, the sampling data in a state where the light receiving sensor overlaps with the paper feed hole is not excluded, and the sampling data in a state where the light receiving sensor does not overlap with the paper feed hole is excluded, and the detection accuracy of the paper edge position is lowered.

  The present invention has been made in view of the above problems, and an object thereof is to accurately detect meandering of a web.

  The invention according to claim 1 is an image recording apparatus for recording an image on a long sheet-like web, wherein the web is transported in a longitudinal direction, and the web is synchronized with the web transport. An image recording unit that records an image on the web, a light source and a photoelectric area sensor that are arranged opposite to each other with the web interposed therebetween, upstream of the image recording unit in the conveyance direction of the web, and the photoelectric area sensor A meandering detection unit for detecting meandering of the web based on an output from the web, wherein the web has a plurality of holes arranged at a constant arrangement pitch along a side edge, and the photoelectric area sensor In the width direction of the web, the light receiving surface extends over a range through which the side edge and the plurality of holes pass, and the meandering detection unit outputs an amount of light received by the photoelectric area sensor. In the sequence, one range that protrudes in the direction in which the output increases is extracted, the peak position of the one range is obtained, and the center position in the transport direction of one hole is obtained based on the peak position Part, and the web transport speed, the length of each hole in the transport direction, the arrangement pitch, and the width in the transport direction of the light receiving surface of the photoelectric area sensor, in the time series of the output, A correction target range extracting unit that extracts a plurality of ranges in which light that has passed through the plurality of holes enters the photoelectric area sensor as a plurality of correction target ranges, and an output of the photoelectric area sensor in each correction target range, A sensor output correction unit configured to correct based on outputs in two correction unnecessary ranges between two correction target ranges adjacent to each other before and after each correction target range; Based on the difference between the predetermined reference and outputs the corrected output by serial sensor output correcting unit and a meandering amount acquisition unit for calculating the meandering amount of the web.

  A second aspect of the present invention is the image recording apparatus according to the first aspect, wherein the image recording apparatus is disposed between the photoelectric area sensor and the image recording unit in the transport direction, and a part of the web is mainly disposed. A meandering correction unit for correcting meandering of the web by rotating about an axis perpendicular to the plane is further provided.

  A third aspect of the present invention is the image recording apparatus according to the second aspect, wherein the light source is disposed opposite to the meandering correction unit on the downstream side in the transport direction with the web interposed therebetween. And another photoelectric area sensor, and a correction range correction unit that corrects the position of the plurality of correction target ranges based on an output from the other photoelectric area sensor, and a light receiving surface of the other photoelectric area sensor However, in the width direction, it exists over the range through which the plurality of holes pass, and the correction range correction unit increases the output in the time series of the output indicating the received light amount of the other photoelectric area sensor. A plurality of ranges protruding to the right are extracted, and the positions of the plurality of correction target ranges are corrected based on the positions of the plurality of ranges.

  Invention of Claim 4 is an image recording device in any one of Claim 1 thru | or 3, Comprising: The width | variety of the said conveyance direction of the said light-receiving surface of the said photoelectric area sensor is the said conveyance direction of each said hole. Or less.

  The invention according to claim 5 is an image recording method for recording an image on the web by an image recording unit in synchronization with the conveyance of the web while conveying a long sheet-like web in the longitudinal direction. The web has a plurality of holes arranged at a constant arrangement pitch along a side edge, and on the upstream side of the image recording unit in the web transport direction, the light source sandwiching the web, and Photoelectric area sensors are arranged opposite to each other, and a light receiving surface of the photoelectric area sensor exists over a range in which the side edge and the plurality of holes pass in the width direction of the web. A) obtaining a time series of outputs indicating the amount of light received by the photoelectric area sensor while conveying the web; and b) a range in which the outputs protrude in the direction in which the output increases in the time series of the outputs. A step of determining a peak position in the one range and determining a center position in the transport direction of one hole based on the peak position; c) a transport speed of the web, and a length of each hole in the transport direction. , Based on the arrangement pitch and the width in the transport direction of the light receiving surface of the photoelectric area sensor, a plurality of light beams that have passed through the plurality of holes are incident on the photoelectric area sensor in the time series of the output. A step of extracting ranges as a plurality of correction target ranges; and d) output of the photoelectric area sensor in each correction target range, two correction target ranges adjacent to the front and rear of each correction target range, and each correction target range. And e) based on the difference between the corrected output in step d) and the reference output determined in advance. And a step of calculating the meandering amount.

  A sixth aspect of the present invention is the image recording method according to the fifth aspect, wherein the step b) is performed immediately after the conveyance of the web is started.

  In the present invention, meandering of the web can be detected with high accuracy. In the invention of claim 2, the meandering of the web can be corrected with high accuracy.

1 is a perspective view of an image recording apparatus according to an embodiment of the present invention. It is a top view which shows a part of web. It is a block diagram which shows the function of a control part. It is a bottom view of a discharge part. It is a figure which shows the flow of the meandering detection of a web. It is a figure which shows the time series of the output of a 1st photoelectric area sensor. It is a figure which shows the time series of the output of a 2nd photoelectric area sensor.

  FIG. 1 is a perspective view showing an appearance of an image recording apparatus 1 according to an embodiment of the present invention. The image recording apparatus 1 is an ink jet printer that discharges micro droplets of ink onto a long sheet-like web 9 to record an image on the web 9 (that is, prints an image). In this embodiment, a color image is recorded on the web 9 which is an opaque printing paper.

  FIG. 2 is a plan view showing a part of the web 9. In FIG. 2, a part of the configuration of the image recording apparatus 1 is depicted. The web 9 has a plurality of holes 92 of the same shape arranged in the longitudinal direction at a constant arrangement pitch along the side edge 91. The hole 92 is used when the web 9 is conveyed at low speed with very high positional accuracy. In the present embodiment, the hole 92 is circular, but the hole 92 may be square or other shapes.

  An image recording apparatus 1 illustrated in FIG. 1 includes a transport mechanism 2, a discharge unit 3, a first sensor unit 4, a meandering correction unit 5, a second sensor unit 6, and a control unit that controls these configurations. FIG. 3 is a block diagram illustrating functions of the control unit 7. FIG. 3 also shows a part of the configuration of the image recording apparatus 1 connected to the control unit 7. The control unit 7 controls a recording control unit 71 that controls the recording of an image on the web 9 and the meandering of the web 9 (that is, the position of the web 9 being transported is shifted in a direction perpendicular to the transport direction). A meandering detection unit 72 for detection is provided. The meandering detection unit 72 includes a center position detection unit 73, a correction target range extraction unit 74, a sensor output correction unit 75, a meandering amount acquisition unit 76, and a correction range correction unit 77.

  The transport mechanism 2 shown in FIG. 1 transports the web 9 in the Y direction in FIG. 1 (that is, the longitudinal direction of the web 9). In the transport mechanism 2, the web 9 is transported without using the holes 92. In the transport mechanism 2, a plurality of rollers 21 that are long in the X direction in FIG. 1 are arranged in the Y direction. The X direction is a direction that is horizontal and perpendicular to the Y direction, and is also the width direction of the web 9. A supply unit 22 for holding a roll-shaped web 9 (supply roll) is provided on the (+ Y) side of the plurality of rollers 21, and a roll-shaped web 9 (winding) is provided on the (−Y) side of the plurality of rollers 21. A winding unit 23 for holding a roll is provided. The web 9 is rolled in each of the supply unit 22 and the winding unit 23. In the following description, the web 9 simply means the web 9 being conveyed (that is, the web 9 on the plurality of rollers 21).

  One roller 21 a of the transport mechanism 2 is provided with an encoder 29 that detects the moving speed of the web 9 in the scanning direction, and the recording control unit 71 (see FIG. 2) is driven by the motor of the winding unit 23 based on the output of the encoder 29. By controlling the rotation of the web 9, the web 9 is conveyed at a constant speed in the (−Y) direction. Hereinafter, the (−Y) direction in FIG. 1 is also referred to as the conveyance direction of the web 9. When the web 9 is conveyed, a load (tension) in the direction opposite to the moving direction (that is, (+ Y) direction) is applied to the web 9 by the motor of the supply unit 22, so The web 9 moves smoothly without undulations.

  The discharge unit 3 is fixed to the frame 25 provided on the base 20 so as to straddle the transport mechanism 2 above the transport mechanism 2 (that is, on the (+ Z) side). FIG. 4 is a bottom view showing the discharge unit 3. The ejection unit 3 includes a plurality of (four in the present embodiment) ink jet heads 31 that eject inks of different colors, and these ink jet heads 31 have the same structure. The plurality of inkjet heads 31 are arranged in the Y direction (that is, the scanning direction) and attached to the attachment part 30 of the ejection part 3.

  The most (+ Y) side inkjet head 31 in FIG. 4 ejects K (black) color ink, and the (−Y) side inkjet head 31 of the K inkjet head 31 is C (cyan) color ink. The (−Y) side inkjet head 31 of the C inkjet head 31 ejects M (magenta) color ink, and the (−Y) side inkjet head 31 has Y (yellow) color ink. Ink is ejected. The ejection unit 3 may be provided with an ink jet head for other colors such as light cyan, light magenta, and white.

  In the image recording apparatus 1, the recording control unit 71 (see FIG. 2) controls the ejection of ink from the ejection unit 3 in synchronization with the conveyance of the web 9 by the conveyance mechanism 2, so that an image is formed on the web 9. Is recorded. That is, the discharge unit 3 functions as an image recording unit that records an image on the web 9. Each inkjet head 31 (see FIG. 4) of the discharge unit 3 is provided over the entire print region on the web 9 (here, over the entire X direction of the web 9) in the X direction. Then, the web 9 is moved only once in the transport direction below the discharge unit 3 to complete the recording of the image on the web 9 (so-called one-pass printing is performed).

  The first sensor unit 4 is disposed on the (−X) side of the web 9 on the upstream side (that is, (+ Y) side) of the web 9 in the conveying direction of the discharge unit 3. The first sensor unit 4 includes a first light source 41 and a first photoelectric area sensor 42. The first light source 41 and the first photoelectric area sensor 42 are arranged to face each other up and down with the web 9 interposed therebetween. In the present embodiment, the first light source 41 is disposed on the (+ Z) side of the web 9, and the first photoelectric area sensor 42 is disposed on the (−Z) side of the web 9.

  In the first photoelectric area sensor 42, as shown in FIG. 2, the (−X) side end of the light receiving surface 421 is located on the (−X) side of the (−X) side edge 91, The end on the (+ X) side of the light receiving surface 421 is located on the (+ X) side of the end on the (+ X) side of the hole 92 on the (−X) side. That is, the light receiving surface 421 extends in a range in which the side edge 91 on the (−X) side of the web 9 and the plurality of holes 92 on the (−X) side pass in the X direction which is the width direction of the web 9. Exist. The width in the Y direction of the light receiving surface 421 of the first photoelectric area sensor 42 is preferably equal to or less than the length of each hole 92 in the Y direction (that is, the diameter of the hole 92), and more preferably the length of the hole 92 in the Y direction. It is 1/2 or less. Although not shown in FIG. 2, the first light source 41 is also present in a range in which the side edge 91 and the plurality of holes 92 of the web 9 pass in the X direction that is the width direction of the web 9.

  As shown in FIG. 1, the meandering correction unit 5 is disposed between the first sensor unit 4 and the discharge unit 3 in the conveyance direction of the web 9. The meandering correction unit 5 includes a cylindrical roller 51 that is long in the X direction. As shown in FIG. 2, the meandering correction unit 5 further includes a rotation mechanism 52 that rotates the roller 51 around an axis 53 (that is, an axis perpendicular to the main surface of the web 9) that faces the Z direction. The roller 51 is disposed between the plurality of rollers 21 (see FIG. 1) of the transport mechanism 2 and is rotated in synchronization with the winding unit 23 of the transport mechanism 2 by a motor (not shown).

  In the meandering correction unit 5, when the roller 51 is rotated by a predetermined angle by the rotation mechanism 52, a part of the web 9 in contact with the upper part of the roller 51 is slightly rotated around the shaft 53, and the meandering of the web 9 is performed. It is corrected. When the roller 51 rotates clockwise in a plan view (that is, viewed from the (+ Z) side), the web 9 on the roller 51 is displaced toward the (+ X) side on the right side in the transport direction. Is rotated counterclockwise, the web 9 is displaced to the (−X) side.

  As shown in FIG. 1, the second sensor unit 6 is arranged on the (−X) side of the web 9 on the downstream side (that is, the (−Y) side) of the web 9 in the conveyance direction of the meandering correction unit 5. The The second sensor unit 6 includes a second light source 61 and a second photoelectric area sensor 62. The second light source 61 and the second photoelectric area sensor 62 are arranged to face each other up and down with the web 9 interposed therebetween. In the present embodiment, the second light source 61 is disposed on the (+ Z) side of the web 9, and the second photoelectric area sensor 62 is disposed on the (−Z) side of the web 9.

  In the second photoelectric area sensor 62, as shown in FIG. 2, the (−X) side end of the light receiving surface 621 is located on the (−X) side of the (−X) side edge 91, The end portion on the (+ X) side of the light receiving surface 621 is positioned on the (+ X) side than the end portion on the (+ X) side of the hole 92 on the (−X) side. That is, the light receiving surface 621 exists over a range in which the plurality of holes 92 on the (−X) side of the web 9 pass in the X direction which is the width direction of the web 9 (the same applies to the second light source 61). The width in the Y direction of the light receiving surface 621 of the second photoelectric area sensor 62 is preferably equal to or less than the length of each hole 92 in the Y direction, and more preferably the Y direction of the hole 92, as in the first photoelectric area sensor 42. Is ½ or less of the length.

  Next, detection of meandering of the web 9 in the image recording apparatus 1 will be described. FIG. 5 is a diagram showing the flow of the meandering detection of the web 9. In the image recording apparatus 1, first, when the web 9 is transported by the transport mechanism 2, an output indicating the amount of light received from the first photoelectric area sensor 42 of the first sensor unit 4 (hereinafter referred to as “light amount output”). The series is acquired by the meander detection unit 72 (see FIG. 3) of the meander correction unit 5 (step S11). FIG. 6 is a diagram showing a part of the time series 81 of the light amount output of the first photoelectric area sensor 42. In FIG. 6, a predetermined reference output is indicated by a two-dot chain line 80 (the same applies to FIG. 7). The reference output is a first output in a state where the light receiving surface 421 does not overlap the hole 92 when the web 9 is transported at a predetermined position in the X direction (hereinafter referred to as “reference position”) without meandering. 1 is a light amount output from the photoelectric area sensor 42.

  When the web 9 meanders from the reference position to the (−X) side, the area covered by the web 9 on the light receiving surface 421 of the first photoelectric area sensor 42 increases, and the light output of the first photoelectric area sensor 42 is the reference output. Smaller than. When the web 9 meanders from the reference position to the (+ X) side, the area covered by the web 9 on the light receiving surface 421 of the first photoelectric area sensor 42 decreases, and the light output of the first photoelectric area sensor 42 is larger than the reference output. Become. The difference between the light output and the reference output is proportional to the amount of deviation of the web 9 from the reference position in the X direction. Further, when the light receiving surface 421 of the first photoelectric area sensor 42 overlaps the hole 92, the light output of the first photoelectric area sensor 42 becomes considerably larger than the reference output.

  In the meandering detection unit 72, the center position detection unit 73 (see FIG. 3) projects a range in which the light output increases in the time series 81 of the light output of the first photoelectric area sensor 42 shown in FIG. 82 (hereinafter referred to as “protrusion range 82”) is extracted. The protruding range 82 corresponds to a time zone in which the light receiving surface 421 of the first photoelectric area sensor 42 overlaps the one hole 92. The start position of the protruding range 82 is extracted as, for example, a point where the amount of change in the light amount output per unit time becomes larger than a predetermined positive threshold in the time series 81 of the light amount output. For example, the end position of the protruding range 82 decreases after the light amount output increases from the start position of the protruding range 82, and is extracted as a point where the amount of change in the light amount output per unit time becomes larger than a predetermined negative threshold. . When the protruding range 82 is extracted, the peak position 83 of the protruding range 82 is obtained, and based on the peak position 83, the center position in the transport direction of one hole 92 corresponding to the protruding range 82 is obtained (step S12). . The peak position 83 of the protrusion range 82 is obtained as a position where the light amount output takes the maximum value in the protrusion range 82. The peak position 83 may be obtained as the center position of the protruding range 82.

  Subsequently, by the correction target range extraction unit 74, a plurality of ranges in which the light that has passed through the plurality of holes 92 is incident on the light receiving surface 421 of the first photoelectric area sensor 42 in the time series 81 of the light output are a plurality of correction targets. A range 84 is extracted (step S13). Extraction of the correction target range 84 includes the peak position 83 of the protrusion range 82 obtained in step S12, the conveyance speed of the web 9 as V, the length of the hole 92 in the conveyance direction as L, and the light reception of the first photoelectric area sensor 42. The width of the surface 421 in the transport direction is Bi, and the pitch P in the transport direction of the plurality of holes 92 is performed.

  Specifically, a position separated by a peak pitch Pc1 (= P / V) starting from the peak position 83 of the protruding range 82 is obtained as the center position of the plurality of correction target ranges 84. Further, the width t1 of each correction target range 84 is obtained as t1 = (L + 2Bi) / V. Thereby, the positions of a plurality of correction target ranges 84 are obtained. In the following description, a plurality of ranges alternately arranged with the plurality of correction target ranges 84 in FIG. The width t2 of each correction unnecessary range 85 is obtained as t2 = P / V−t1.

  Next, the light output of the first photoelectric area sensor 42 in each correction target range 84 by the sensor output correction unit 75 includes two correction target ranges 84 adjacent to each other before and after each correction target range 84, and each correction target range 84. Is corrected based on the light amount output in the two unnecessary correction ranges 85 between (step S14). In the present embodiment, in the two unnecessary correction ranges 85 before and after the correction target range 84, the light amount output at the position closest to the correction target range 84 is acquired, and the two light amount outputs are linearly interpolated, thereby correcting the correction. The correction output of the target range 84 (that is, the received light amount when it is assumed that the hole 92 does not exist) is obtained. In FIG. 6, the correction output of the correction target range 84 is drawn by a broken line 81a. The correction of the light amount output in the correction target range 84 may be performed by, for example, spline interpolation based on a plurality of light amount outputs in the two adjacent unnecessary correction ranges 85.

  Then, the meandering amount of the web 9 is calculated based on the difference between the output corrected by the sensor output correcting unit 75 and the reference output 80 (step S15). That is, the meandering amount at the position corresponding to the correction target range 84 is obtained based on the difference between the correction output of the correction target range 84 and the reference output, and the meandering amount at the position corresponding to the correction unnecessary range 85 is corrected. It is obtained based on the difference between the light amount output in the unnecessary range 85 and the reference output.

  In the image recording apparatus 1, when the meandering of the web 9 is detected based on the light amount output from the first photoelectric area sensor 42, the correction amount for correcting the meandering from the meandering detection unit 72 to the meandering correction unit 5. Is instructed. Then, the meandering correction unit 5 corrects the meandering of the web 9 and returns the web 9 to the reference position. In the ejection unit 3, ink is ejected onto the web 9 conveyed at the reference position, and an image is recorded on the web 9 with high positional accuracy. In the image recording apparatus 1, while the web 9 is being conveyed, the above-described meander detection (steps S11 to S15), meander correction, and image recording are repeated.

  The web 9 that has passed through the discharge section 3 is further transported in the transport direction, and the (−X) side end of the web 9 passes through the second sensor section 6. The output indicating the amount of received light of the second photoelectric area sensor 62 of the second sensor unit 6 is sent to the meandering detection unit 72 (see FIG. 3), and the time series of the light amount output of the second photoelectric area sensor 62 is the correction range. Acquired by the correction unit 77. FIG. 7 is a diagram showing a part of the time series 86 of the light amount output of the second photoelectric area sensor 62. Since the position of the web 9 in the X direction is the reference position by the meandering correction unit 5, the light output is equal to the reference output 80 at the position where the light receiving surface 621 of the second photoelectric area sensor 62 does not overlap the hole 92. .

  In the meandering detection unit 72, the correction range correction unit 77 extracts a plurality of protruding ranges 87 protruding in the direction in which the light output increases in the time series 86 of the light output of the second photoelectric area sensor 62. The protruding range 87 corresponds to a time zone in which the light receiving surface 621 of the second photoelectric area sensor 62 overlaps the hole 92. In the correction range correction unit 77, a range in which the light amount output is larger than the reference output 80 is extracted as the protruding range 87 at high speed. The extraction of the protruding range 87 may be performed by the same method as the extraction of the protruding range 82 described above.

  Subsequently, the center position of each protruding range 87 is obtained as a peak position, and the correction of the positions of the plurality of correction target ranges 84 (see FIG. 6) is performed based on the peak positions of the plurality of protruding ranges 87. Specifically, the peak pitch Pc2 of the plurality of projection ranges 87 is obtained based on the peak positions of the plurality of projection ranges 87, and the peak pitch Pc2 and the plurality of correction target ranges 84 obtained by calculation in step S13 are calculated. The peak pitch Pc1 is compared. Actually, a time between peaks at both ends of a predetermined number (for example, 101) of the protruding range 87 is obtained and compared with a multiple (100 times) of the corresponding peak pitch Pc1.

  For example, when the peak pitch Pc1 is larger than the actual peak pitch Pc2, the position of the correction target range 84 that is away from the protruding range 82 due to the accumulation of the error is that the light that has actually passed through the hole 92 is the first photoelectric area. It shifts to the rear side of the range incident on the light receiving surface 421 of the sensor 42. Therefore, when the peak pitch Pc2 is different from the peak pitch Pc1, the positions separated from the peak position 83 of the projecting range 82 by the peak pitch Pc2 by the same method as the calculation of the center positions of the plurality of correction target ranges 84 in step S13. The center position of the plurality of correction target ranges 84 is obtained. The new positions of the plurality of correction target ranges 84 obtained by the correction range correcting unit 77 (that is, the positions of the corrected correction target ranges 84) are sent to the correction target range extracting unit 74, and the positions are determined in step S14. The light output of the first photoelectric area sensor 42 in the corrected correction target range 84 is corrected by the sensor output correction unit 75.

  In the correction of the position of the correction target range 84 by the correction range correction unit 77 described above, for example, the start position or the end position of the protrusion range 87 may be used instead of the peak position of the protrusion range 87. In other words, the correction range correcting unit 77 corrects the positions of the plurality of correction target ranges 84 based on the positions of the plurality of protruding ranges 87.

  As described above, in the image recording apparatus 1, a plurality of correction target ranges 84 corresponding to the plurality of holes 92 of the web 9 are extracted in the time series 81 of the light amount output of the first photoelectric area sensor 42, and each correction is performed. The light amount output of the target range 84 is corrected based on the light amount output of the adjacent correction unnecessary range 85. Then, the meandering amount of the web 9 is calculated based on the difference between the corrected output and the reference output. As a result, the meandering amount of the web 9 can be calculated with high accuracy even at a portion where the hole 92 exists in the side portion of the web 9. As a result, the meandering of the web 9 can be accurately detected over the entire longitudinal range. In addition, the meandering correction unit 5 can correct the meandering of the web 9 with high accuracy, and can record an image on the web 9 with high positional accuracy.

  In the meandering detection unit 72, the correction range correction unit 77 corrects the positions of the plurality of correction target ranges 84 based on the output from the second photoelectric area sensor 62. Accordingly, it is possible to prevent a decrease in accuracy of position detection of the correction target range 84 due to a measurement error of the encoder 29, and to perform meandering detection of the web 9 with higher accuracy.

  In the image recording apparatus 1, even if the width of the light receiving surface 421 in the transport direction is longer than the length of the hole 92 in the transport direction, the meandering of the web 9 can be detected and corrected with high accuracy, but step S12. When calculating the peak position 83 of the protrusion range 82, complicated calculation is required. Therefore, as described above, by setting the width of the light receiving surface 421 in the conveyance direction to be equal to or less than the length of the hole 92 in the conveyance direction, the peak position 83 of the protruding range 82 can be easily obtained. Further, when the width of the light receiving surface 421 in the transport direction is set to ½ or less of the length of the hole 92 in the transport direction, the peak position 83 of the protruding range 82 can be obtained more easily.

  In step S12, when the number of times of light amount measurement per unit time by the first photoelectric area sensor 42 is larger, the accuracy of extraction of the protruding range 82 and calculation of the peak position 83 is improved, and one corresponding to the protruding range 82 is obtained. The center position of the hole 92 can be obtained with high accuracy. Therefore, step S12 is preferably performed immediately after the start of the conveyance of the web 9 in which the conveyance speed of the web 9 is relatively small and the number of times of light amount measurement per unit time by the first photoelectric area sensor 42 can be increased.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, if the meandering of the web 9 can be detected with sufficiently high accuracy, the second sensor unit 6 and the correction range correction unit 77 may be omitted. Further, instead of performing the meandering correction of the web 9 by the meandering correction unit 5, the amount of meandering of the web 9 is sent from the meandering detection unit 72 to the recording control unit 71, and the ejection sent from the recording control unit 71 to the ejection unit 3. The signal may be corrected based on the amount of meandering. Also in this case, an image is recorded on the web 9 with high positional accuracy.

  In the image recording apparatus 1, one-pass printing is performed in which printing of an image on the web 9 is completed only by passing the web 9 below the discharge unit 3 once. However, even if the image is recorded by other methods, Good. For example, a mechanism for moving a discharge part having a plurality of discharge ports arranged in the longitudinal direction of the web 9 in the width direction of the web 9 is provided, and the discharge part crosses the web 9 once above the web 9. In addition, the image may be recorded on the web 9 by repeating the movement of the web 9 in the longitudinal direction by a predetermined distance.

  In the image recording apparatus 1, for example, an image may be recorded on an opaque or translucent long sheet-like web formed of plastic. Alternatively, a fine droplet of a fluid material other than ink may be ejected from the ejection unit 3, and an image may be recorded on the object by the fluid material. For example, even when a paste containing metal particles is selected as a fluid material and a fine droplet of the paste is discharged onto a web which is a long sheet-like flexible substrate, a wiring pattern is recorded as an image on the web. Good. The image recording apparatus 1 may be provided with image recording units having various structures other than the ejection unit 3. For example, a transfer mechanism for transferring a toner image held on the surface by electrophotography to a web may be provided as the image recording unit.

  The configurations in the above embodiment and each modification may be appropriately combined as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Image recording apparatus 2 Conveyance mechanism 3 Discharge part 5 Meander correction part 9 Web 41 1st light source 42 1st photoelectric area sensor 53 Axis 61 2nd light source 62 2nd photoelectric area sensor 72 Meander detection part 73 Center position detection part 74 Correction object Range extraction unit 75 Sensor output correction unit 76 Meander amount acquisition unit 77 Correction range correction unit 80 Reference output 81 Time series 82 Projection range 83 Peak position 84 Correction target range 85 Correction unnecessary range 86 Time series 87 Projection range 91 Side edge 92 Hole 421 Light-receiving surface 621 Light-receiving surface S11-S15 Step

Claims (6)

An image recording apparatus for recording an image on a long sheet-like web,
A transport mechanism for transporting the web in the longitudinal direction;
An image recording unit for recording an image on the web in synchronization with conveyance of the web;
A light source and a photoelectric area sensor disposed opposite to each other across the web, on the upstream side of the web recording direction from the image recording unit;
A meandering detection unit for detecting meandering of the web based on an output from the photoelectric area sensor;
With
The web has a plurality of holes arranged at a constant arrangement pitch along the side edges;
The light receiving surface of the photoelectric area sensor exists in a width direction of the web over a range through which the side edge and the plurality of holes pass,
The meander detection unit is
In the time series of outputs indicating the received light amount of the photoelectric area sensor, one range protruding in the direction in which the output increases is extracted, the peak position of the one range is obtained, and one hole is determined based on the peak position. A center position detection unit for obtaining a center position in the transport direction;
Based on the transport speed of the web, the length of each hole in the transport direction, the arrangement pitch, and the width in the transport direction of the light receiving surface of the photoelectric area sensor, A correction target range extraction unit that extracts a plurality of ranges in which light that has passed through the hole enters the photoelectric area sensor as a plurality of correction target ranges;
The output of the photoelectric area sensor in each correction target range is corrected based on outputs in two correction unnecessary ranges between the two correction target ranges adjacent to each other and the correction target ranges. A sensor output correction unit;
A meandering amount acquisition unit that calculates a meandering amount of the web based on a difference between an output after correction by the sensor output correction unit and a predetermined reference output;
An image recording apparatus comprising: The image recording apparatus according to claim 1,
A meandering correction that is arranged between the photoelectric area sensor and the image recording unit in the transport direction and corrects meandering of the web by rotating a part of the web around an axis perpendicular to the main surface. An image recording apparatus further comprising a unit. The image recording apparatus according to claim 2,
Other light sources and other photoelectric area sensors disposed opposite to each other across the web, on the downstream side in the transport direction from the meandering correction unit,
A correction range correction unit for correcting the positions of the plurality of correction target ranges based on outputs from the other photoelectric area sensors;
Further comprising
The light receiving surface of the other photoelectric area sensor exists in a range in which the plurality of holes pass in the width direction,
The correction range correction unit extracts a plurality of ranges protruding in a direction in which the output increases in a time series of outputs indicating the received light amount of the other photoelectric area sensor, and based on the positions of the plurality of ranges, An image recording apparatus for correcting positions of the plurality of correction target ranges. The image recording apparatus according to any one of claims 1 to 3,
The width of the light receiving surface of the photoelectric area sensor in the transport direction is equal to or less than the length of the holes in the transport direction. An image recording method for recording an image on the web by an image recording unit in synchronization with conveyance of the web while conveying a long sheet-like web in the longitudinal direction,
The web has a plurality of holes arranged at a constant arrangement pitch along the side edges;
On the upstream side of the web recording direction from the image recording unit, a light source and a photoelectric area sensor are arranged opposite to each other with the web interposed therebetween, and a light receiving surface of the photoelectric area sensor is arranged in the width direction of the web. A side edge and a range over which the plurality of holes pass;
The image recording method comprises:
a) obtaining a time series of outputs indicating the amount of light received by the photoelectric area sensor while conveying the web;
b) In the time series of the outputs, one range protruding in the direction in which the output increases is extracted, the peak position of the one range is obtained, and the center of the one hole in the transport direction based on the peak position A process for determining a position;
c) Based on the transport speed of the web, the length of each hole in the transport direction, the arrangement pitch, and the width in the transport direction of the light receiving surface of the photoelectric area sensor, in the time series of the output, Extracting a plurality of ranges where light passing through a plurality of holes is incident on the photoelectric area sensor as a plurality of correction target ranges;
d) The output of the photoelectric area sensor in each correction target range is based on the outputs in the two unnecessary correction ranges between the two correction target ranges adjacent to each other and the correction target ranges. A process of correcting,
e) calculating a meandering amount of the web based on a difference between the corrected output in the step d) and a predetermined reference output;
An image recording method comprising: The image recording method according to claim 5,
The image recording method, wherein the step b) is performed immediately after the start of conveyance of the web.

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