JP2011056833A - Recorder and method for acquiring conveyance error correction value - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exactly obtain a correction value for correcting a conveyance error of a recording medium without being influenced by eccentricity of a roller even if the conveyance error can be measured only in a range which does not fulfill one round of the roller. <P>SOLUTION: By fitting a plurality of conveyance amount data detected based on continuous conveyance of the recording medium by a plurality of number of times which is performed in a range less than peripheral length of the roller by a periodic function, the correction value for correcting the conveyance error of the roller is acquired. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a conveyance error correction value acquisition method, and more particularly to a technique for acquiring a correction value for correcting a conveyance error of a recording medium used in an inkjet recording apparatus.

  An ink jet recording apparatus records an image on a recording medium by using a recording head in which fine nozzles are arranged and ejecting ink from each nozzle according to recording data to form dots. Accordingly, in order to form a high-quality image, it is an important issue to prevent the dot formation position from being shifted on the recording medium. The deviation of the dot formation position occurs due to various factors such as variations in the nozzle shape of the recording head, noise components such as vibration of the apparatus during the recording operation, and the distance between the recording medium and the recording head. The present inventors have recognized that one of the major factors that cause the deviation of the dot formation position is the conveyance accuracy of the recording medium. Usually, a roller (conveyance roller) is used in the recording medium conveyance unit, and the recording medium is conveyed by a desired length by rotating the conveyance roller by a specified angle while the recording medium is pressed against the recording medium. Is possible.

A major cause of such a decrease in conveyance accuracy is an error in the outer circumference or outer diameter of the roller. If there is an error in the outer diameter of the roller, even if the roller is rotated by a rotation angle determined for a roller having a certain reference outer diameter, a predetermined conveyance amount cannot be obtained, and preferable continuity of images is not ensured. Will appear. In other words, if a roller with an outer diameter larger than the reference outer diameter is used, the conveyance amount will be larger than the predetermined conveyance amount, and in the so-called serial printer type device, it is between the image areas recorded by the movement of the recording head. A stripe-shaped blank portion (white stripe) is generated. Conversely, if a roller having an outer diameter smaller than the reference outer diameter is used, the conveyance amount becomes smaller than a predetermined conveyance amount, and a stripe-like high density portion (black streak) is generated between image areas.
Similarly, it has been found that the conveyance amount of the recording medium is affected by variations in the surface condition of the roller. This is because the frictional force acting between the roller and the recording medium differs depending on the surface condition of the roller, resulting in a difference in the amount of slip. As a result, the conveyance control amount that is the command value of the printing apparatus may differ from the actual conveyance amount.

  In order to prevent image defects caused by variations in the outer diameter of the roller and the surface state of the roller as described above, a special pattern is recorded for each individual recording device, a transport error is detected from the pattern, and the transport amount There is a method of performing correction.

  However, the conveyance accuracy of the recording medium greatly depends on the eccentricity of the conveyance roller. When the cross-sectional shape of the transport roller is a perfect circle and the central axis and the rotation axis coincide with each other, the transport rotating body is rotated by an angle R, assuming that the rotation angle for transporting the recording medium is uniform. The length in the circumferential direction (the length of the arc) when rotating is constant. Accordingly, the conveyance amount of the recording medium conveyed in contact with the conveyance roller is constant no matter where it is taken. However, when the cross section of the transport roller is an ellipse, even if the transport rotator is rotated by the same angle R, the transport amount differs depending on the rotation position of the transport roller. Further, since the rotation axis of the conveyance roller is deviated from the central axis of the design, the recording medium conveyance fluctuation depending on the period may occur. That is, when the rotation axis is deviated from the central axis, the conveyance amount varies with respect to a predetermined rotation angle of the conveyance roller, and the recording medium conveyance variation depending on the cycle of the conveyance rotator occurs.

  The eccentricity of the roller means a state where the cross-sectional shape of the roller is not a perfect circle as described above, or a state where the rotation axis is deviated from the central axis of the conveying roller.

  In order to perform high-quality image recording without unevenness, it is necessary to reduce the influence of the eccentricity of the rollers in order to correct the influence of the outer diameter error of the conveying roller.

  The amount of eccentricity of the conveyance roller is usually devised so as to be kept below a certain level, but the yield of the conveyance roller decreases as the standard for the amount of eccentricity becomes stricter, leading to an increase in the manufacturing cost of the recording apparatus. It is not preferable that the standard for the amount of eccentricity is too strict.

  Therefore, a technique has been proposed in which a test pattern is recorded at a rotational position of the roller every 180 °, or is recorded at a rotational position of the roller every 120 ° to reflect an error in the conveyance amount according to the phase of the roller. (Patent Document 1). In other words, the conveyance amount is appropriately corrected by taking the average value of the values determined from the test patterns of two or three rows formed at intervals of rotation of 180 ° or 120 °. .

  By using the technique disclosed in Patent Document 1, it is possible to reduce the influence of roller eccentricity. However, in Patent Document 1, when there is a restriction that the number of test patterns corresponding to one rotation of the roller cannot be recorded, or when there is a restriction that the test pattern cannot be recorded at a rotational position such as 180 ° or 120 °, an appropriate roller is used. There is a problem that a correction value cannot be obtained.

  20A to 20C are views showing a state where the recording medium is being conveyed. At the time of recording, the recording medium P is sandwiched between a conveying roller 1 that is one of a plurality of rollers provided on the conveying path and a pinch roller 2 that is driven by the recording medium P. 3 is conveyed from the right side to the left side in the figure while being guided and supported. A pinch roller 2 is elastically urged against the conveying roller 1 by a pressing member such as a spring (not shown). The transport roller 1 and the pinch roller 2 constitute the upstream transport unit. The recording medium P that has been transported and recorded on the platen 3 is then transported by being sandwiched between the rotating discharge roller 12 and a spur 13 that is a rotating body that follows this. These discharge rollers 12 and spurs 13 constitute the components of the downstream transport unit.

  Accordingly, the recording medium P is supported and transported only by the upstream transport unit, is supported and transported by both transport units, and is supported and transported only by the downstream transport unit (FIG. 20A, respectively). The three states (b) and (c)) can be taken.

  Since the conveyance amount error due to the influence of roller eccentricity or the like varies depending on the combination of rollers involved in conveyance, the conveyance errors in the above three states are measured separately, and a conveyance amount correction value corresponding to each is set. Is preferred. In general, however, the recordable area corresponding to FIGS. 20A and 20C is often narrow. The reason for this is as follows. During recording in the recordable area corresponding to FIGS. 5A and 5C, one end of the recording medium is free without being sandwiched between rollers. The size of these recordable areas is determined by the interval between the transport roller and the discharge roller. However, the wider this interval, the more likely it is that the recording medium comes into contact with the recording head due to warping of the recording medium. It is. Therefore, in general, the printable area corresponding to (a) and (c) of FIG. 5 must be narrowed, and accordingly, the conveyance amount error detection pattern is sufficient to record over one roller. In many cases, it is not possible to secure a secure area.

  When the technique disclosed in Patent Document 1 is applied to such a configuration, an average of values determined from test patterns formed at several rotational positions in a region less than one rotation of the roller, that is, less than 360 degrees. Will take the value. However, when there is an eccentricity as described above, the average value varies depending on the position of the region, and therefore there is a high possibility that the conveyance error correction value obtained therefrom will not be appropriate.

  FIG. 21 is a schematic diagram showing the result of measuring the transport error. (B) in the figure is the result of measuring the conveyance amount error for one rotation of the roller, and any roller is affected by the eccentricity of the roller to a greater or lesser extent. In general, it exhibits periodic characteristics. However, as shown in FIGS. 20A and 20C described above, in the front end region and the rear end region of the recording medium, there may be a case where the transport amount error can be measured only in a region less than one turn of the transport roller and the discharge roller. Many. For this reason, as shown in FIGS. 21A and 21C, only a part of the transport error periodically distributed can be acquired. When the transport error correction value is obtained from the average value of these transport amount error measurement data, the average values in the cases of FIGS. 21A, 21B, and 21C are “3.8” and “3. 1 ”and“ 2.3 ”. That is, although FIGS. 21A and 21C are data obtained by extracting only a part of the data in FIG. 21B, such a difference is obtained only by the difference in the range for obtaining the average value. It will occur. This means that the conveyance error correction value obtained from the range in which the conveyance error is measured is not appropriate. In this case, the transport error correction value obtained by calculating the average value from the data of FIG. 21B in which the transport error measurement value in the range of one cycle is obtained is the most appropriate.

  Further, an example in which the conveyance error correction value cannot be obtained accurately will be given. FIGS. 22A and 22B are schematic views showing the results of measuring the transport error. However, in this case, since the detection pattern can be recorded only every 66 degrees of the roller angle due to restrictions on recording of the conveyance error detection pattern, it is assumed that a measurement value for one rotation of the roller cannot be obtained accurately. Yes. Therefore, when trying to acquire data close to one round, it is obtained from the average value of data up to 330 degrees as shown in FIG. 22 (a) or data up to 396 degrees as shown in FIG. 22 (b). . The average values in the cases of FIGS. 22A and 22B are “3.06” and “3.26”, respectively. That is, it can be seen that the correction value also differs depending on the method of acquiring the data for obtaining the transport error correction value, and the transport error correction cannot be performed properly.

JP 2004-122361 A

  The present invention can accurately obtain a correction value for correcting a conveyance error of a recording medium without being affected by the eccentricity of the roller even if the conveyance error can be measured only within a range of less than one rotation of the roller. By doing so, an object is to be able to contribute to high-quality image recording.

  Therefore, the present invention provides a recording apparatus including a roller for conveying a recording medium, and a plurality of continuous recording medium conveyances performed within a range less than the circumferential length of the roller. And a detection unit for detecting conveyance amount data, and an acquisition unit for acquiring a correction value for correcting the conveyance error of the roller by fitting the plurality of conveyance amount data with a periodic function. And

  The present invention also provides a transport error correction value acquisition method for acquiring a correction value for correcting a transport error of the roller in a recording apparatus including a roller for transporting a recording medium, By detecting a plurality of conveyance amount data based on a plurality of continuous conveyances of the recording medium performed in a range less than a length, and by fitting the plurality of conveyance amount data with a periodic function, An acquisition step of acquiring a correction value for correcting the conveyance error.

  According to the present invention, even if the conveyance error can be measured only within a range of less than one rotation of the roller, the correction value for correcting the conveyance error of the recording medium is reduced by reducing the influence of the eccentricity of the roller. It will be obtained. Thereby, it becomes possible to contribute to high-quality image recording.

1 is a schematic perspective view illustrating an overall configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram schematically illustrating a state in which the recording head employed in the embodiment of FIG. 1 is viewed from the nozzle forming surface side. FIG. 2 is a block diagram illustrating a configuration example of a main part of a control system of the ink jet recording apparatus of FIG. 1. It is a flowchart which shows the outline | summary of the process sequence for acquiring a conveyance error correction value. It is explanatory drawing which shows an example of the test pattern used by embodiment of this invention. FIG. 6 is an explanatory diagram of an aspect in which the entire recording area of the recording medium is divided into an area where the upstream conveying unit is involved in the conveying operation and an area where the recording medium is conveyed only by the downstream conveying unit. It is explanatory drawing of the nozzle usage condition at the time of test pattern formation. It is explanatory drawing of the formation mode of the test pattern using the upstream nozzle group NU and the downstream nozzle group ND in FIG. 7, or the patch which comprises this. (A) And (b) is explanatory drawing which respectively shows the reference | standard patch element group and adjustment patch element group which are recorded by one recording operation. It is explanatory drawing of the formation aspect of the test pattern FR in the area | region I of FIG. It is explanatory drawing which shows the detail of the test pattern FR of FIG. It is explanatory drawing of the formation aspect of the test pattern in the area | region II of FIG. It is explanatory drawing which expands and shows a reference | standard patch element and the patch element for adjustment. It is explanatory drawing which expands and further shows the patch element of FIG. (A) And (b) is explanatory drawing for demonstrating the density change by interference with a reference | standard patch element and an adjustment patch element. It is explanatory drawing for demonstrating the process for pinpointing the point used as the minimum density from each patch line shown by FIG. (A) And (b) is explanatory drawing for demonstrating the process for acquiring a conveyance error correction value from the test pattern FR formed in the area | region I of FIG. (A) And (b) is explanatory drawing for demonstrating the process for acquiring a conveyance error correction value from the test pattern FR formed in the area | region I of FIG. It is explanatory drawing for demonstrating the image with the nonuniformity resulting from eccentricity of a roller. (A) and (b) are explanatory views for explaining different conveyance states of the recording medium, and (c) is a state where the conveyance by the upstream conveyance unit is canceled and the conveyance is performed only by the downstream conveyance unit. It is explanatory drawing for. (A)-(c) is explanatory drawing of the problem of the prior art which obtains a conveyance error correction value. (A) And (b) is explanatory drawing of the problem of the prior art which obtains a conveyance error correction value.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(1) Device Configuration FIG. 1 is a schematic perspective view showing the overall configuration of an ink jet recording apparatus according to an embodiment of the present invention. At the time of recording, the recording medium P is sandwiched between a conveying roller 1 that is one of a plurality of rollers provided on the conveying path and a pinch roller 2 that is driven by the recording medium P. 3 is conveyed in the direction of arrow A in the figure while being guided and supported. A pinch roller 2 is elastically urged against the conveying roller 1 by a pressing member such as a spring (not shown). The transport roller 1 and the pinch roller 2 constitute the upstream transport unit.

  The platen 3 is provided at a recording position facing the surface (ejection surface) on which the ejection port of the recording head 4 in the form of an ink jet recording head is formed, and supports the back surface of the recording medium P so that the surface of the recording medium P The distance from the discharge surface is maintained at a constant or predetermined distance.

  The recording medium P that has been transported and recorded on the platen 3 is then sandwiched between a rotating discharge roller 12 and a spur 13 that is a rotating body that is driven by the recording roller P, and is transported in the A direction. Are discharged onto the paper discharge tray 15. These discharge rollers 12 and spurs 13 constitute the components of the downstream transport unit. In FIG. 1, only one pair of the discharge roller 12 and the spur 13 is shown, but two pairs may be provided as will be described later.

  14 is a member that is disposed on one side of the recording medium and that serves as a conveyance reference when conveying the recording medium. Regardless of the width dimension, the recording medium has one side along the conveyance reference member 14. Are transported. The conveyance reference member 14 may also be used for the purpose of restricting the recording medium P from floating upward, that is, toward the ejection surface of the recording head 4.

  The recording head 4 is detachably mounted on the carriage 7 with its discharge surface facing the platen 3 or the recording medium P. The carriage 7 is reciprocated along the two guide rails 5 and 6 by a motor as a driving source, and the recording head 4 can perform an ink ejection operation in the course of the movement. This carriage movement direction is a direction orthogonal to the recording medium conveyance direction (arrow A direction). Recording on the recording medium P is performed by alternately repeating the movement of the carriage 7 or the recording head 4 and the conveyance of the recording medium.

  Here, the recording head 4 includes an element (for example, a heating resistance element) that generates thermal energy as energy used for ink ejection, and causes a change in ink state (film boiling) by the thermal energy. Can be used. Further, an element that generates mechanical energy such as a piezo element as an energy generating element, and a system that ejects ink by the mechanical energy may be used.

  The recording apparatus of the present embodiment forms an image with 10 color pigment inks. The ten colors are cyan (C), light cyan (Lc), magenta (M), light magenta (Lm), yellow (Y), first black (K1), second black (K2), red (R), and green. (G) and Gray. The K ink is the ink of the first black K1 or the second black K2 described above. Here, the first black K1 ink and the second black K2 ink are respectively a photo black ink that realizes high glossy recording on glossy paper and a matte black ink that is suitable for matte paper without gloss. be able to.

  FIG. 2 schematically shows a state in which the recording head 4 employed in the present embodiment is viewed from the nozzle forming surface side. The recording head 4 of this example has two recording element substrates H3700 and a recording element substrate H3701 in which nozzle rows for each of the ten colors are formed. H2700 to H3600 are nozzle rows corresponding to 10 different colors of ink, respectively.

  One recording element substrate H3700 is provided with nozzle rows H3200, H3300, H3400, H3500, and H3600 that are supplied with gray, light cyan, first black, second black, and light magenta inks and perform ejection operations. . On the other recording element substrate H3701, nozzle rows H2700, H2800, H2900, H3000, and H3100 are formed which are supplied with cyan, red, green, magenta, and yellow inks and perform ejection operations. Each nozzle row is composed of 768 nozzles arranged at an interval of 1200 dpi (dot / inch) in the conveyance direction of the recording medium, and ejects ink droplets of about 3 picoliters. The opening area at each nozzle outlet is set to approximately 100 square μm.

  With such a head configuration, it is possible to execute so-called one-pass printing in which printing on the same area on the printing medium is completed by one printing scan. However, in order to reduce variations in nozzles and improve recording quality, it is also possible to execute so-called multi-pass recording in which recording on the same recording scanning area on the recording medium is completed by a plurality of recording scans. . The number of passes at the time of multi-pass recording is appropriately determined according to the recording mode and other conditions.

  A plurality of independent ink tanks are detachably attached to the recording head 4 according to the color of the ink to be used. Alternatively, ink may be supplied from an ink tank provided at a fixed portion of the apparatus via a liquid supply tube.

  In the non-recording area that is within the movable range of the recording head 4 in the moving direction and outside the side edge of the recording medium P or the platen 3, the recovery unit 11 can face the ejection surface of the recording head 4. Has been placed. The recovery unit 11 has a known configuration as described below. That is, a cap portion for capping the ejection surface of the recording head 4, a suction mechanism for forcibly sucking ink from the recording head 4 in a state where the ejection surface is capped, and a cleaning blade for wiping off dirt on the ink ejection surface.

  FIG. 3 shows a configuration example of a main part of a control system of the ink jet recording apparatus according to the present embodiment. Here, reference numeral 100 denotes a control unit that controls each unit of the ink jet recording apparatus according to the present embodiment. The control unit 100 includes a CPU 101, a ROM 102, an EEPROM 103, and a RAM 104. The CPU 101 performs various calculations and determinations for processing related to the recording operation and the like, including processing procedures to be described later, and performs processing for print data and the like. The ROM 102 stores a program corresponding to a processing procedure executed by the CPU 101, other fixed data, and the like. The EEPROM 103 is a non-volatile memory and is used to hold predetermined information even when the recording apparatus is turned off. The RAM 104 temporarily stores print data supplied from the outside and print data expanded in accordance with the apparatus configuration, and also functions as a work area for arithmetic processing by the CPU 101.

  The interface (I / F) 105 has a function of connecting to an external host device 1000 and performs bidirectional communication with the host device 1000 based on a predetermined protocol. The host device 1000 has a known form such as a computer, and serves as a print data supply source for causing the recording apparatus of this embodiment to perform printing, and a printer driver which is a program for causing the printing operation to be performed. Installed. That is, the printer driver sends print data, print setting information such as the type information of the recording medium on which the print data is printed, and a control command for controlling the operation of the recording apparatus.

  The linear encoder 106 detects the position of the recording head 4 in the moving direction. The sheet sensor 107 is provided at an appropriate position on the recording medium conveyance path. By detecting the leading and trailing edges of the recording medium using the sheet sensor 107, the conveyance position of the recording medium can be known. Motor drivers 108 and 112 and a head drive circuit 109 are connected to the control unit 100. Under the control of the control unit 100, the motor driver 108 drives the transport motor 110 that is a recording medium transport drive source. The driving force of the conveyance motor 110 is transmitted to the conveyance roller 1 and the discharge roller 2 through a transmission mechanism such as a gear. The motor driver 112 drives a carriage motor 114 that is a driving source for moving the carriage 7. The driving force of the carriage motor 114 is transmitted to the carriage 7 via a transmission mechanism such as a timing belt. The head drive circuit 109 drives the recording head 4 under the control of the control unit 100 to perform an ejection operation.

  The rotary encoder 116 is attached to the shafts of the transport roller 1 and the discharge roller 2 and is used for controlling the transport motor by detecting the respective rotational positions and speeds.

  The reading sensor 120 is used as a detector that detects the density of an image recorded on the recording medium P. As a form thereof, a reading head mounted on the carriage 7 together with or instead of the recording head 4 may be used, or an image reading apparatus configured separately from the recording apparatus of FIG. Good.

(2) Outline of processing In the recording apparatus configured as described above, one of the major causes of a decrease in conveyance accuracy is that depending on the error of the roller outer diameter. If there is an error in the outer diameter of the roller, a predetermined conveyance amount cannot be obtained even if the roller is rotated by a rotation angle determined with respect to a certain reference outer diameter. In other words, if a roller having a larger outer diameter than the reference outer diameter is used, the conveyance amount increases and white streaks are likely to occur in the recorded image. Conversely, if a roller having an outer diameter smaller than the reference outer diameter is used. The carry amount is reduced and black streaks are likely to occur in the recorded image.

  In view of this, the present embodiment basically aims to provide a configuration that can suppress the deviation of the dot formation position due to insufficient conveyance accuracy due to the outer diameter error of the conveyance roller and the discharge roller. In addition, this embodiment reduces the influence of the eccentricity of the roller and acquires a correction value (conveyance error correction value) for reducing the outer diameter error with high accuracy, and rotates the roller during actual recording, that is, the conveyance motor. This is applied to drive control. As described above, the eccentricity of the roller means that the rotational axis is deviated from the central axis of the roller and the rotational central axis is eccentric with respect to the geometrical central axis, or the sectional shape of the roller is true. A state that is not a circle.

  FIG. 4 is a flowchart showing an outline of a processing procedure for obtaining a conveyance error correction value. In this procedure, first, preparation for starting a recording operation including setting and feeding of a recording medium is performed (step S9), and when the recording medium is conveyed to a predetermined recording position, a test pattern is recorded (step S11). This test pattern can simultaneously detect a conveyance amount error (hereinafter also referred to as a conveyance error) due to an eccentricity and an outer diameter error, which will be described later. Next, the test pattern is read using the reading sensor 120, and the density information is acquired (step S13). Then, based on the density information, a process for obtaining a correction value for correcting the conveyance error of the recording medium (step S15) is executed.

(3) Test Pattern FIG. 5 shows an example of a test pattern used in this embodiment. In the present embodiment, a test pattern for detecting a transport error of the transport roller 1 and a test pattern for detecting a transport error of the discharge roller 12 are formed side by side in a direction corresponding to the recording medium transport direction. That is, in the figure, FR is a test pattern for detecting the transport error of the transport roller 1, and ER is a test pattern for detecting the transport error of the discharge roller 12.

  Here, the reason for recording the test patterns of the transport roller 1 and the discharge roller 12 is as follows.

  In the recording apparatus of the present embodiment, transport units are respectively provided on the upstream side and the downstream side in the recording medium transport direction from the position (recording position) where recording is performed by the recording head 4. Therefore, the recording medium P can take three states as described above. That is, a state of being supported and transported only by the upstream transport unit, a state of being supported and transported by both transport units, and a state of being supported and transported only by the downstream transport unit (FIGS. 20A and 20B, respectively) (C)).

  Here, the conveyance roller 1 and the discharge roller 12 often have a slight difference in conveyance accuracy due to the difference in their main roles. The main role of the transport roller 1 is to position the recording medium at an appropriate position with respect to the recording head 4 for each recording scan. Therefore, it has a sufficiently large roller diameter, and can perform a transport operation with relatively high accuracy. On the other hand, the main role of the discharge roller 12 is to reliably discharge the recording medium after recording. Therefore, the conveyance accuracy of the recording medium is often inferior to that of the conveyance roller 1.

  Therefore, the conveyance error of the recording medium is related to the conveyance accuracy when the conveyance roller 1 is involved in the conveyance operation, and is related to the conveyance accuracy when only the discharge roller 12 is involved in the conveyance operation. become.

  Therefore, in the present embodiment, as shown in FIG. 6, the conveyance roller 1 is divided into an area I where the conveyance operation is involved and an area II where the recording medium is conveyed only by the discharge roller 12. Then, test patterns are recorded while being transported by rollers mainly involved in each transport operation, density information is acquired from each test pattern, and correction values applied during actual recording in each region To get. The recording apparatus of the present embodiment is configured as a recording apparatus capable of realizing an image having no margin at the front and rear end portions of the recording medium, that is, so-called “marginless recording”, and the recording medium is conveyed only by the discharge roller 12. Acquiring the correction value in this case is effective when recording without margins at the rear end.

  Here, in the actual operation of the recording apparatus, the area II to be recorded while being transported only by the downstream transport unit is narrow, and as shown below the broken line in FIG. Only test patterns can be formed. For this reason, in the present embodiment, an appropriate conveyance error correction value is obtained by performing processing as described later.

  In the present embodiment, even when the conveyance roller 1 and the discharge roller 12 are used for conveyance, the conveyance accuracy of the conveyance roller 1 is dominant with respect to the conveyance error. I decided to divide it. However, if the transport error differs between the case where only the transport roller 1 is involved in the transport (the recording medium front end portion) and the case where both the transport roller 1 and the discharge roller 12 are involved in the transport, Furthermore, processing can be performed by dividing the area. In this case, if a test pattern can be formed only in an area that is less than one round of the transport roller 1, a process as described later is applied to the leading end of the recording medium to obtain an appropriate transport error correction value. it can.

(4) Details of Test Pattern Each test pattern shown in FIG. 5 is formed as follows.

  FIG. 7 is an explanatory diagram of a mode of nozzle use during test pattern formation. For forming the test pattern, for example, out of 768 nozzles included in the second black nozzle row H3500, a part of the nozzle group NU which is located relatively upstream in the transport direction and continuous, and relatively downstream Another part of the nozzle group ND located on the side and continuing is used.

  In this example, the nozzle group ND on the downstream side is used as a reference nozzle group, and 120 nozzles in the 1st to 120th range from the nozzle located on the most downstream side are fixedly used, and a plurality of reference patch elements are used. Record (first patch element). On the other hand, the upstream nozzle group NU is an adjustment nozzle group, and the number of nozzles to be used is 120, which is the same as that of the downstream nozzle group ND. At this time, a plurality of adjustment patch elements (second patches) are shifted while the range to be used is shifted one nozzle at a time around the nozzle group in the 129th to 248th range from the nozzle located at the most downstream position. Element).

  FIG. 8 is an explanatory diagram of a test pattern using the upstream nozzle group NU and the downstream nozzle group ND, or a mode of forming a patch constituting the test pattern. The operation of forming the adjustment patch element in the recording scan (scan 0) at a certain transport position, then transporting the medium for 128 nozzles, and forming the next recording scan adjustment patch element is repeated. Since the adjustment patch element formed first reaches the position of the downstream nozzle group ND at the second recording scan (scan 1), a patch (1 for acquiring density information by forming a reference patch element there) (Line) is completed.

  Similarly, the adjustment patch element formed in the second recording scan reaches the position of the downstream nozzle group ND in the third recording scan (scan 2). Therefore, by forming a reference patch element, the patch in the second row is completed. Patches in the third and subsequent rows are formed in the same manner, and a plurality of rows of patches are completed in the transport direction.

  That is, in order to complete the patch, in this embodiment, one medium conveyance is interposed between the scan for forming the adjustment patch element and the scan for forming the reference patch element. Therefore, each of the patches included in the test pattern of the present embodiment is used for one medium conveyance interposed between the recording scan in which the adjustment patch element is formed and the recording scan in which the reference patch element is formed. This reflects the conveyance error in the roller area.

  FIGS. 9A and 9B respectively show a reference patch element group and an adjustment patch element group that are recorded in one printing scan. As shown in FIG. 9A, the reference patch elements RPE are recorded in alignment in the recording scanning direction, whereas as shown in FIG. 5B, the adjustment patch element APE is equivalent to one nozzle pitch. It will be recorded shifted by one. The group of adjustment patch elements APE includes adjustment standard patch elements APEr recorded using 120 nozzles in the 129th to 248th range from the nozzle located at the most downstream position.

  The adjustment patch element on the side of the conveyance reference member 14 (left side in the figure) from the adjustment standard patch element APEr toward the conveyance reference side, the usage range of the adjustment nozzle group NU one nozzle at a time in the conveyance direction downstream. It has been recorded with a shift. Conversely, the adjustment patch element on the non-conveyance reference side (right side in the figure) from the adjustment standard patch element APEr increases the use range of the adjustment nozzle group NU on the upstream side in the conveyance direction one nozzle at a time as it moves away from the conveyance reference. It has been recorded staggered. The shift range is 3 nozzles on the transport reference side and 4 nozzles on the non-transport reference side. If the shift is positive, the entire shift range is −3 to +4.

  Here, the recording medium is conveyed without error by a distance (128/1200 × 25.4 = 2.709 [mm]) corresponding to the range of 128 nozzles arranged at a pitch of 1200 dpi between the recording scans. Shall. Then, the reference patch element RPE recorded in the second recording scan having passed through one medium is exactly overlapped with the adjustment standard patch element APEr (shift amount 0) recorded in a certain recording scan. Further, a positive shift amount corresponds to a larger carry amount than the distance, and a negative shift amount corresponds to a smaller carry amount.

  FIG. 10 shows how the test pattern FR is formed, and FIG. 11 shows the details. The test pattern FR is formed in the region I in FIG. 6, and the region is wide, and the length in the transport direction can be in a range that is greater than or equal to the circumferential length of the transport roller 1.

  Since the adjustment patch element APE is recorded by shifting one nozzle at a time in the range of −3 to +4 nozzles relative to the adjustment standard patch element APEr, eight patches are formed in the recording scanning direction for one test pattern. Will be. In the present embodiment, the medium conveyance amount (ideal value) between the recording scans is set to 2.709 mm, and 14 recording patches are formed over the range in the conveyance direction by repeating 13 recording scans. To do. For this reason, the length of the test pattern FR in the transport direction is 2.709 × 14 = 37.93 mm (ideal amount). When a roller having a nominal outer circumference of 37.19 mm is used, this is equivalent to one round. Equivalent to super.

  10 and 11, the patch string indicated by the symbol A is a patch string including the adjustment standard patch element APEr. The patch rows indicated by A + 1 to A + 4 are adjustment patch elements recorded by shifting the use range of the adjustment nozzle group NU by 1 to 4 nozzles upstream of the adjustment standard patch element APEr on the upstream side in the transport direction. It is a patch string that contains. The patch rows indicated by A-1 to A-3 are for adjustment recorded by shifting the use range of the adjustment nozzle group NU from the adjustment standard patch element APEr by 1 to 3 nozzles on the downstream side in the transport direction. A patch string including patch elements.

  Each patch row indicated by reference numerals B1 to B14 is formed by different roller areas used for medium conveyance between the scan for creating the adjustment patch element and the scan for creating the reference patch element. It is. It is assumed that the medium is transported from the reference position of the roller after recording the patch element for adjustment in the patch row B1. In this case, in the patch row B1, an area (0 to 2.709 mm) corresponding to one medium conveyance from the reference position of the roller is used from the scan for creating the adjustment patch element to the scan for creating the reference patch element. That's right. In the patch row B2, an area (2.709 to 5.418 mm) corresponding to the next one-time medium conveyance is used. Similarly, the roller area (5.418 to 8.127 mm) is used in the patch row B3, and the roller area (8.127 to 10.8339 mm) is used in the patch row B4. Thus, in each patch row, different roller areas are used from the scan for creating the adjustment patch element to the scan for creating the reference patch element.

  FIG. 12 shows details of the test pattern ER. The test pattern ER is formed in the region II of FIG. 6 and the region is generally narrow, so that it is often impossible to form a test pattern having a length in the conveyance direction for one circumference of the discharge roller. When the conveyance amount between recording scans is 128 nozzle length (2.709 [mm]) as described above, in the example of FIG. 12, only patch rows indicated by reference numerals B1 to B8 can be formed. Here, the length of the test pattern ER in the conveyance direction is about three-fifths of a discharge roller having a nominal outer circumference of 34.56 mm.

(5) Details of Patch FIG. 13 is an enlarged view of the reference patch element and the adjustment patch element. FIG. 14 is a view showing these patch elements in an enlarged manner. The patch element is formed as a stepped pattern having a recording block of 2 dots in the carrying direction and 10 dots in the recording scanning direction as a basic unit. Further, the distance in the transport direction between the staircase patterns is secured in consideration of the range in which the used nozzle group is shifted. In the illustrated example, 6 nozzles (6 to 6) (6 to 6) correspond to shifting 1 to 4 nozzles (+1 to +4) on the upstream side in the transport direction and 1 to 3 nozzles (-1 to -3) on the downstream side in the transport direction. (Dots) apart.

  In the present embodiment, patch elements as shown in this figure are recorded in both the upstream nozzle group NU and the downstream nozzle group ND. For this reason, the overlapping state of the reference patch element and the adjustment patch element changes according to the level of the transport error, and patches of various densities are present in the test patterns FR and ER as shown in FIGS. Will be formed.

  That is, if the adjustment patch element recorded by the upstream nozzle group NU and the reference patch element recorded by the downstream nozzle group ND overlap as shown in FIG. 15A, the density (OD value) is low. Become. On the other hand, if these are shifted, the blank portion is filled as shown in FIG.

  In the present embodiment, the area factor is reduced as the reference patch element and the adjustment patch element overlap each other, and a patch having a lower density is formed. The area factor increases as the reference patch element and the adjustment patch element overlap each other, and a patch having a high density may be formed. In short, it is sufficient that the density information changes sensitively with respect to the degree of overlap or deviation between the reference patch element and the adjustment patch element (that is, the conveyance error).

  Further, in this embodiment, each patch element is formed by a recording block arranged in a staircase pattern, but the recording block is not continuous in the recording scanning direction, and the influence of ejection defects can be effectively reduced. For example, other arrangements can be used. For example, the recording blocks may be arranged in spots, or may be arranged randomly.

  In the present embodiment, mat black ink is used to form the test pattern. However, the ink used may be of other colors as long as the density information can be satisfactorily acquired using the reading sensor. Ink of different colors may be used for the reference patch element and the adjustment patch element.

  Further, the number of nozzle groups to be used and the position of the used nozzles are not limited to the above examples as long as the change in density information with respect to the conveyance error can be obtained satisfactorily and is not easily affected by the nozzle ejection failure. For example, the nozzle groups NU and ND need only have a positional relationship in which the distance between them is obtained by multiplying the number of print scans performed before the patch elements overlap with the amount of conveyance performed between the print scans.

  In addition, the configuration of the patch is not limited to the interference pattern as described above.

(6) Acquisition of Carriage Error Correction Value (6-1) Process for Region I First, in the present embodiment, the density of the patches constituting the test pattern is measured using the reading sensor 120. The reading sensor 120 scans an optical sensor having a light emitting portion and a light receiving portion on the test pattern, thereby causing a patch (FIGS. 15A and 15B) in which the reference pattern and the adjustment pattern interfere with each other. Measure the concentration. That is, the density of the patch is detected as a reflected light amount (reflected light intensity) when the patch is irradiated with light. This detection operation may be performed only once for the detection area. However, by performing the detection operation a plurality of times, the influence of the detection error can be reduced.

  For each patch row, the density of each patch of A-3 to A + 4 columns recorded in the recording scanning direction is detected, and the one with the lowest density is specified. Next, when the density of the three patches including both sides is plotted, it is distributed in a quadratic curve as shown in FIG. Therefore, the amount of dot deviation that is the minimum point of this quadratic curve is obtained, and the transport error is calculated based on this.

  For example, as shown in FIG. 16, when the density of the patch in the A column is the minimum, a quadratic curve approximation is performed for the three points of the density value and the density values of the patches in the A-1 column and the A + 1 column on both sides thereof. I do. It can be seen that the minimum in the function corresponding to this is a shift amount of about -0.17 dots. By approximating the quadratic curve in this way, it is possible to calculate the transport error with a finer precision from patches shifted by 1200 dpi units (21.17 micron units). That is, when −0.17 is set to the minimum value, 21.17 × (−0.17) = − 3.60 μm is the deviation amount (transport error) from the ideal transport length.

  For the test pattern FR formed in the region I, this process is performed for every 14 patch rows formed in the transport direction. As a result, a transport error is detected for each circumferential length (2.709 mm) of the roller used in one medium transport in each patch row.

  FIG. 17A is an example in which the transport error for each medium transport (LF) obtained by the above procedure is plotted. Since the transport amount of one medium is 128 nozzles (128/1200 × 25.4 = 2.709 [mm]) and the outer peripheral length of the transport roller 1 is 37.19 mm, the transport rollers in the patch rows B1 to B14 Can cover more than one lap. The transport amount data shows a distribution in which the outer peripheral length of any of the rollers used for transport is a period, although there is an individual difference in amplitude. Depending on the configuration of the recording apparatus, the cycle corresponding to which roller is different, but in the present embodiment, in region I, the transport roller 1 is mainly involved in transport, and thus affects transport errors. That is, the transport error has a distribution with the outer peripheral length of the transport roller 1 as a cycle. This is due to the eccentricity of the transport roller, encoder scale, gear, and the like.

  What is required to determine the transport error correction value is the average value of the medium transport length before correction. If the average value is determined from data that is an integral multiple of the period, the average value of the medium transport length before correction can be calculated. However, the uncorrected medium transport length data that can be obtained from the relationship between the transport length during test pattern recording in the present embodiment (the length of the test pattern in the transport direction) and the outer peripheral length of the transport roller 1 is an integral multiple of the period. It is not. While the outer peripheral length of the transport roller 1 is 37.19 mm, the length in the sub-scanning direction of the patch rows B1 to B13 is 128/1200 × 25.4 × 13 = 35.22 mm, and the transport of the patch rows B1 to B14 is performed. The length in the direction is 128/1200 × 25.4 × 14 = 37.93 mm.

  Therefore, if the average value is obtained from the data of the patch rows B1 to B14, a fraction exceeding one turn of the conveying roller 1 is reflected in the average value calculation as an error factor. On the other hand, in this embodiment, the average of the acquired data is not calculated, but the acquired data is fitted with a periodic function, and the average value of one period of the obtained function is calculated. Since the conveyance error caused by the eccentricity of the roller is normally distributed in a sine function, the sine function is used for fitting in this embodiment. At the time of fitting, the fitting function can be efficiently obtained by setting the period of the conveying roller 1 that is dominant in the region I to the period of the sine function.

FIG. 17B shows a general sine function y = a × sin (2π / L × x−b) + c (1)
An example in which fitting is performed with L corresponding to the period of 37.19 mm is shown. Then, c obtained as a result of the fitting corresponds to an average value for one cycle of the sine function to be obtained now.

An example of the fitting method will be described. The transport amount of each of the 14 patch rows acquired from the test pattern this time is {Y (1), Y (2), Y (3),..., Y (14)}.
And When the fitting function is a sine function as described above, the transport amount of the nth patch row is y (n) = a × sin (2π / L × x (n) −b) + c (2)
And the carry amount for 14 times is {y (1), y (2), y (3), ..., y (14)}
Can be shown.

Here, if the root mean square value S (n) of Y (n) and y (n) is defined,
S (n) ² = (Y (1) −y (1)) ² + (Y (2) −y (2)) ²
+ (Y (3) −y (3)) ² +... + (Y (n) −y (n)) ² (3)
It becomes. An optimum sine function is obtained by obtaining a, b, and c that minimize this S. A combination of (a, b, c) that calculates S (n) in a state where various combinations of numerical values of (a, b, c) are set within an effective range and S (n) is the smallest. Of the sine functions obtained by finding, what is desired now is the value of c. In the present embodiment, the value of c obtained as a result of fitting the data of FIG. 17B is 12.5 μm. Accordingly, the conveyance amount correction value is −12.5 μm of the opposite sign.

The correction value obtained here is for carrying 128 nozzles, which is the carry control command value at the time of test pattern FR recording, and another correction value is used when carrying the other carry amount. In general, it is desirable to increase or decrease the conveyance control correction value in proportion to the conveyance control command value. Taking these into consideration, using C (transport control correction value per unit transport length) and B (pre-correction transport control command value) obtained from the test pattern, A (corrected transport control command value) is determined as follows. It is done.
A = B × (1 + C) (4)
The above procedure is a procedure for calculating the conveyance control correction value in the region I shown in FIGS. 5 and 6 using the conveyance roller in this embodiment.

(6-2) Processing for area I Next, the trailing edge of the recording medium passes through the upstream conveyance unit (conveyance roller 1 and pinch roller 2) and is conveyed only by the downstream conveyance unit (discharge roller 12 and spur 13). A procedure for acquiring the conveyance control correction value after switching to (FIG. 20C) will be described. As described above, since the recordable range after the trailing edge of the recording medium passes through the upstream transport unit is generally narrow, it is often impossible to record for one round of the discharge roller. A case will be described in which recording is possible only for a half circumference that is less than the circumference of the roller. Here, the outer peripheral length of the discharge roller is 34.56 mm, and the transport amount when recording the test pattern ER is 128 nozzle lengths (128/1200 × 25.4 = 2) as in the test pattern recording for the transport roller 1. .709 [mm]).

  As shown in FIG. 5, in this embodiment, since the area I is wide, it is possible to record the test pattern FR for the transport roller 1 over one cycle length of the transport roller. Even in the region II where the recording medium is transported only by the discharge roller 12, it is desirable to record a test pattern for one cycle of the discharge roller in terms of measurement accuracy. For this purpose, the transport roller 1 and the discharge roller 12 are kept away from each other. In many cases. However, the farther these are, the larger the area to be recorded in a state where the recording medium is supported only by the discharge roller 12 in the recording area at the rear end of the recording medium. For this reason, when the recording medium is warped, the contact with the recording head occurs, and there is a high possibility that the recorded image is soiled.

  In the present embodiment, as shown in FIG. 12, the test pattern ER corresponding to eight conveyances less than one cycle of the discharge roller is recorded, and the conveyance amount data is fitted to a periodic function to obtain accuracy. Secure. In other words, the interval between the conveyance roller 1 and the discharge roller 12 is set to a minimum, and the conveyance control with high accuracy is realized while avoiding contact with the recording head at the rear end of the recording medium as much as possible.

  FIG. 18A is an example in which the transport error for each medium transport (LF) in the region II is plotted. This corresponds to the test pattern ER (including the patch rows B1 to B8) involving eight times of medium conveyance less than one cycle of the discharge roller, and the conveyance amount is corrected in the same manner as in the case of the region I. The value can be obtained. That is, as shown in FIG. 18B, the conveyance roller correction value is obtained by setting the cycle of the discharge roller 12 to the cycle of the sine function and performing the same processing as the above equations (1) to (3). can do.

  Here, if an average value of eight data corresponding to the patch rows B1 to B8 is obtained, as described above with reference to FIG. However, according to the method according to the present embodiment, a preferable correction value can be obtained even in such a case. That is, when the eight data shown in FIG. 18 are simply averaged to be −10.1 μm, the result obtained from the fitting is −8 μm, and a more preferable transport error correction value can be obtained.

  The two transport error correction values obtained as described above (the correction value when the transport roller 1 is involved in transport and the correction value when only the discharge roller 12 is involved in transport) are, for example, the EEPROM 103 (FIG. 3). ). Then, according to the progress of the recording, the areas I and II may be used properly. Further, when the procedure as shown in FIG. 4 is executed, the stored contents of the EEPROM may be updated.

(7) Others The above processing may be performed in accordance with a user instruction, or may be performed by bringing it into a service person or a service center. In any case, if it is stored in the EEPROM, the correction value can be updated as appropriate, and it is possible to cope with a change with time of the roller or the like.

  However, if the change over time does not matter so much and it is not necessary to update the correction value after shipment, the default value of the correction value is determined in the inspection process at the time of shipment from the factory, and the ROM 102 storing this is installed in the recording apparatus. do it. In this sense, the transport error correction value acquisition method of the present invention characterized by the determination of the transport error correction value is not necessarily realized by the recording apparatus, but is realized by an apparatus or inspection system separate from the recording apparatus. It is possible.

  In such a case, it is possible to pay attention to the constant a among the constants a, b, and c obtained as a result of the fitting, and to notify an error when this numerical value is larger than a predetermined numerical value. In the sine function, a corresponds to the amplitude, and the larger this value, the easier the periodic unevenness appears in the image. FIG. 19 is a schematic view of unevenness caused by the eccentricity of the roller. Therefore, after investigating in advance how large the value of a would be when the unevenness reached an unacceptable level, the threshold value A of a was set to a predetermined value and stored in a ROM or the like, while the result of fitting was obtained. The value of a is compared with the threshold A. If the threshold A is exceeded, an error can be generated to notify the operator. In accordance with this result, the operator can stop shipping the recording apparatus and replace the parts related to the conveyance. The threshold A is as follows. The threshold value for the transport roller and the threshold value for the discharge roller may be set to different values.

  As another embodiment, the conveyance error correction value may be acquired based on density information obtained by scanning a test pattern using a reading sensor 120 mounted on a carriage together with a recording head. Good. Alternatively, density information may be obtained by scanning a test pattern using a reading sensor 120 in the form of a reading head mounted in place of the recording head, and the measurement may be performed based on this. In other words, the recording medium is set first, the test pattern as described above is formed, the recording medium is reset in the apparatus after the formation, and the reading of the test pattern is performed to obtain the density information. it can.

  Further, in the case of a recording apparatus that does not have a reading sensor inside (including the case where the recording apparatus is configured as a multi-function apparatus having an integrated scanner unit), the recording medium on which the test pattern is formed is connected to the external scanner apparatus. It may be set and read. That is, a recording medium on which a test pattern is formed may be set in an external scanner device, and a conveyance error correction value may be acquired in response to input of density information read there. In addition, the calculation of the correction value is not performed as a process on the recording apparatus side, but can be performed as a process of a printer driver operating on a host device 1000 in a computer form connected to the recording apparatus. That is, the density information read by the external scanner device is provided to the host device 1000 to calculate the correction value, and the recording device stores (updates) the correction value in the EEPROM 103 when the correction value is input. Good.

  In addition, in the above example, the configuration in which the conveyance roller and the discharge roller are respectively provided on the upstream side and the downstream side in the recording medium conveyance direction has been described. However, the recording medium is transported by various transport units until the recording medium is fed and recording is completed. Other than the above-mentioned rollers at the time of recording are also involved in the conveyance, and if there is a concern about the influence of the conveyance error due to the eccentricity or variation in the outer diameter, individually with respect to those rollers or with other rollers In this combination, a correction value for the conveyance error can be acquired. Also in this case, the test pattern can be recorded in the same manner as described above, and the conveyance error correction value can be acquired from the density information. In other words, test pattern recording and correction value acquisition can be performed according to the number and combination of transport units involved in transport during recording, which enables uniform and high-quality recording on the entire recording medium. It becomes feasible.

  For example, when there are two rollers used for conveyance, processing can be performed for the case where the conveyance roller is involved in conveyance as described above and the case where only the discharge roller is involved in conveyance. Furthermore, the process can be performed separately for the case where only the transport roller is involved in transport and the case where the transport roller is involved in transport in cooperation with the discharge roller. Even in the former case, even when the size of the region is small, the conveyance error correction value can be obtained with high accuracy by performing the same process as when only the discharge roller is involved in the conveyance. When there are three rollers, the processing can be divided into a maximum of five cases (areas) in the same manner. Generally speaking, when carrying by using n (n ≧ 2) rollers, the processing can be performed by dividing into a maximum of 3 + 1/2 [n (n−1)] areas.

  In addition, when performing fitting effectively with a sine function, it is preferable that there is conveyance length data that is at least 1/4 of the cycle, and the reliability of fitting can be improved by expanding the data acquisition range. Further, since the data amount increases as the data acquisition pitch (conveyance pitch at the time of test pattern recording) is shorter, the reliability of fitting can be improved.

  In addition, the number of ink color tones (color, density, etc.) used, the type of ink, the number of nozzles, the mode of setting the used nozzle range and the conveyance amount of the recording medium, and various numerical values are merely examples, It goes without saying that an appropriate one can be adopted.

  In the above example, the case where the present invention is applied to a so-called serial type ink jet recording apparatus has been described. However, the present invention is also applicable to a so-called line printer type ink jet recording apparatus using a line type head in which nozzles are aligned over a range corresponding to the width of the recording medium. In this case, such a line type head can be arranged on the upstream side and the downstream side in the transport direction. On the one hand, the reference patch element as described above is recorded, and on the other hand, the adjustment patch element is recorded while shifting the recording timing to obtain the test pattern, so that the roller transport error is known and the correction value is obtained. Can do.

1 Conveying roller 4 Recording head 12 Discharging roller 103 EEPROM
120 Reading sensor 1000 Host device (computer)
FR, ER test pattern P Recording medium

Claims (9)

A recording apparatus comprising a roller for conveying a recording medium,
Detection means for detecting a plurality of conveyance amount data based on a plurality of continuous conveyances of the recording medium performed in a range less than the circumference of the roller;
An acquisition means for acquiring a correction value for correcting a conveyance error of the roller by fitting the plurality of conveyance amount data with a periodic function;
A recording apparatus characterized by comprising:   The recording apparatus according to claim 1, wherein a sine function is used as the periodic function.   The recording apparatus according to claim 1, wherein the circumferential length of the roller, which is a dominant factor of the conveyance error, is set in the period of the periodic function.   4. The detection unit according to claim 1, wherein the detection unit forms a test pattern for detecting the conveyance error on a recording medium, and detects the plurality of conveyance amount data based on the test pattern. A recording apparatus according to claim 1.   A recording scan in which recording is performed while moving a recording head on which nozzles for ejecting ink are arrayed in a direction different from the direction of the array, and the recording medium in a direction orthogonal to the direction of the recording scan The recording apparatus according to claim 4, wherein an image is recorded by performing the conveyance of the image. The test pattern includes two patch elements, and includes a plurality of patches whose density changes depending on the overlapping state of the two patch elements.
One of the patch elements is formed by fixedly using a part of the nozzle group that is continuous among the nozzles, and the other patch element is a part of the other nozzle group that is different from the part of the nozzle group. The recording apparatus according to claim 5, wherein the recording apparatus is formed using different positions.   A plurality of the rollers, and according to the state of involvement of the plurality of rollers in the conveyance of the recording medium, the detection unit conveys the recording medium a plurality of times in a range less than the circumference of the roller. And detecting the plurality of conveyance amount data based on a plurality of continuous conveyances of the recording medium performed in a range equal to or greater than the circumference of the roller. The recording apparatus according to claim 1, wherein a correction value of the conveyance error is acquired according to a state of participation of the plurality of rollers in conveyance of the recording medium. A transport error correction value acquisition method for acquiring a correction value for correcting a transport error of the roller in a recording apparatus including a roller for transporting a recording medium,
A detection step of detecting a plurality of conveyance amount data based on a plurality of continuous conveyances of the recording medium performed in a range less than the circumference of the roller;
An acquisition step of acquiring a correction value for correcting the conveyance error of the roller by fitting the plurality of conveyance amount data with a periodic function;
A conveyance error correction value acquisition method comprising:   9. The transport error correction value acquisition method according to claim 8, further comprising a step of notifying an error according to a periodic function fitted to the plurality of transport amount data.

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