JP2004354611A - Image recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct the position of a recording head with high accuracy in each traveling unit only by disposing a distance sensor which is mounted on one of a plurality of traveling units and measures the distance from the peripheral face of a drum in the direction of the optical axis. <P>SOLUTION: A focus curve relating to the varying state of the correction amount according to the position on a drum 1 is preliminarily acquired by measuring with a distance sensor 38, and the positions of recording heads 22, 23 are corrected on the basis of the focus curve. In particular, the variance ΔP of the gap distance caused by environmental changes is acquired during recording, and the position of the recording head is corrected by considering the variance ΔP. The variance ΔP is obtained by comparing the proper value preliminarily acquired relating to the traveling unit having the distance sensor with the measured value obtained during recording. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image recording apparatus that records an image by wrapping a plate as a recording medium around a drum and irradiating a laser beam.
[0002]
[Prior art]
In an image recording apparatus that performs image recording by irradiating a laser beam, a sensor is used to separate a recording head from a recording plate in order to avoid defocusing caused by a change in an optical axis direction of the recording head due to an environmental temperature change. 2. Description of the Related Art There is known an image recording apparatus configured to correct a position of a recording head in an optical axis direction by actually measuring a distance (see Patent Document 1). According to this, it is also effective against a defocus caused by a manufacturing error or an assembly error of a constituent member, and a great effect is obtained in improving the quality of a recorded image.
[Patent Document 1]
JP-A-2002-98925
[Problems to be solved by the invention]
By the way, as disclosed in the related art, an image having a configuration in which an image is recorded on a plate by winding and holding a recording plate around a drum, rotating the drum and moving a recording head in the axial direction of the drum. In the recording apparatus, if the recording head has a two-head configuration in which two recording heads are arranged in the axial direction (sub-scanning direction), the recording operation can be speeded up.
[0004]
However, in the case where two traveling units each having two recording heads individually mounted thereon travel along the guide rail, it is desirable to provide a sensor for each of the two traveling units, since this leads to an increase in cost. Instead, it is desired to provide a configuration capable of accurately correcting the position of the recording head for each traveling unit only by providing a sensor in one of the traveling units.
[0005]
The present invention has been devised based on the knowledge of the inventor, and its main purpose is to provide a configuration having a plurality of traveling units, and to provide a sensor only to one of the plurality of traveling units. An object of the present invention is to provide an image recording apparatus configured so that position correction of a recording head of a traveling unit can be accurately performed.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, the present invention includes a drum around which a recording plate is wound, a recording head that irradiates the recording plate with light for exposure, and a position correction unit that corrects a position of the recording plate in an optical axis direction. A plurality of traveling units capable of traveling in the axial direction of the drum along the same guide rail, and measuring a separation distance in an optical axis direction with respect to an outer peripheral surface of the drum mounted on any of the plurality of traveling units. A distance sensor, storage means for storing position-specific correction information relating to a variation state of the correction amount according to the position on the drum, which is obtained in advance by a measurement operation by the distance sensor, and the position stored in the storage means Recording control means for causing the recording head to perform recording while correcting the position of the recording head by the position correction means based on the separate correction information. It was as. According to this, it is possible to accurately correct the position of the recording head of each traveling unit only by providing a sensor in any of the plurality of traveling units.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An image recording apparatus according to a first embodiment of the present invention includes a drum around which a recording plate is wound, a recording head that irradiates the recording plate with light for exposure, and a position correction unit that corrects a position of the recording plate in an optical axis direction. A plurality of traveling units capable of traveling in the axial direction of the drum along the same guide rail, and a separation distance in the optical axis direction with respect to the outer peripheral surface of the drum mounted on any of the plurality of traveling units. A distance sensor to be measured, storage means for storing position-specific correction information relating to a variation state of the correction amount according to the position on the drum, which is obtained in advance by a measurement operation by the distance sensor, and stored in the storage means. Recording control means for causing the recording head to perform recording while correcting the position of the recording head by the position correction means based on the position-specific correction information. It is.
[0008]
According to this, by correcting the position of the recording head based on the position-specific correction information, it is possible to avoid defocus, and, in a plurality of traveling units traveling on the same guide rail, according to the position on the drum. The variation of the correction amount is almost the same, and if the recording head of each traveling unit is set to an appropriate position in advance according to the manufacturing error and the assembly error of the constituent members, the correction according to the position on the drum is performed. By the position correction based on the fluctuation state of the amount, even a traveling unit having no distance sensor can secure sufficient accuracy for practical use. For this reason, it is not necessary to separately provide a distance sensor for a plurality of traveling units, and an increase in manufacturing cost can be suppressed.
[0009]
In this case, the correction information for each position relates to a correction amount corresponding to the position of the drum in the axial direction (sub-scanning direction), and the position correction of the recording head is performed in the sub-scanning direction feed period in which the recording head is moved in the axial direction during recording. It is good to do. According to this, it is possible to sufficiently secure the time required for correcting the separation distance without lowering the recording speed, and it is possible to perform highly accurate and stable correction.
[0010]
An image recording apparatus according to a second embodiment of the present invention is the image recording apparatus according to the first embodiment, wherein at the time of recording, the image recording apparatus is separated from a reference point set on the outer peripheral surface of the drum. Measurement control means for causing the distance sensor to measure the distance, and arithmetic means for acquiring recording-time correction information regarding the amount of change in the separation distance due to an environmental change based on the measurement result of the separation distance by the measurement control means. And a recording control unit that corrects the position of the recording head based on the recording-time correction information. According to this, it is possible to correct the fluctuation of the separation distance caused mainly by the expansion and contraction of the components due to the change of the environmental temperature, and it is possible to ease the limitation of the installation use condition due to the environmental temperature.
[0011]
In this case, it is preferable to set the reference point on the blank surface (plate non-mounting surface). This makes it possible to perform the work of measuring the separation distance for the reference point when the drum is in the standby position for attaching and detaching the recording plate, and it takes extra time for the measurement work. There is no need to secure them, and the recording process can be sped up. Moreover, since the blank surface that does not come into contact with the recording plate is to be measured, the blank surface is less susceptible to the effects of foreign matter such as dust, and highly accurate measurement is possible.
[0012]
In the image recording apparatus according to the third embodiment of the present invention, the storage unit is obtained in advance by performing a work of measuring a separation distance with respect to the reference point in an adjusted state so that appropriate image recording is possible. The appropriate value for the traveling unit provided with the distance sensor is further stored, and the arithmetic unit compares the measured value acquired at the time of recording by the measurement control unit with the appropriate value of the storage unit. Thus, the amount of fluctuation due to the environmental change is calculated. According to this, the fluctuation amount of the separation distance can be accurately and easily acquired.
[0013]
An image recording apparatus according to a fourth embodiment of the present invention, wherein the drum is formed in such a manner that open portions at both ends of a cylindrical pipe-shaped member are closed by lid-shaped members provided with a rotating shaft, A plurality of measurement points set on the outer peripheral surface of the drum to obtain correction information are arranged such that a central portion in the axial direction is denser than both end portions in the axial direction of the drum. . According to this, the variation in the separation distance is relatively small at both axial end portions that are solid in the lid-like member, and the variation in the separation distance is relatively large at the axial central portion that is hollow, and at this axial central portion. By making the measurement points dense, it is possible to perform high-accuracy correction that is responsive to variations in the separation distance.
[0014]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a front view showing the entire image recording apparatus according to the present invention. This image recording apparatus is used for making a printing plate in newsprint printing. A recording unit 2 for recording images by winding recording plates A and B around a drum 1 and a recording plate A A plate supplying unit 3 for supplying B, a plate discharging unit 4 for taking recorded recording plates A and B from the recording unit 2 and sending the recording plates to the outside, and one required recording plate A and B from the skid 5 and the cassette 6 And a suction unit 8 that picks up each plate and transfers it to the plate supply unit 3.
[0016]
FIG. 2 is a side view of the image recording apparatus shown in FIG. In this image recording apparatus, two types of recording plates, a standard-width recording plate A that can be mounted side by side on the drum 1 and a double-width recording plate B that can be mounted on the drum 1, can be used. The pair of skids 5 on which the recording plates A having the standard width are loaded are arranged side by side on the floor surface. Further, the cassette 6 accommodating the double-width recording plate B is loaded on a cassette tray 11 which can move forward and backward.
[0017]
A pair of the suction portions 8 are provided side by side so as to correspond to the pair of skids 5 and are supported by the guide posts 13 directly above the skids 5 so as to be able to move up and down. The suction unit 8 includes a suction pad 12 for holding the recording plates A and B. The suction unit 8 descends from the illustrated standby position, picks up the recording plate A on the skid 5, rises, and protrudes to the lower position. The recording plate A is placed on the plate feeding unit 3. The recording plate B on the cassette 6 protruding above the skid 5 is picked up by a pair of suction units 8 and conveyed to the plate feeding unit 3.
[0018]
After receiving the recording plates A and B from the suction unit 8, the plate feeding unit 3 returns to the standby position, and then sends the recording plates A and B to the drum 1 of the recording unit 2, and the recording process on the recording plates A and B ends. Then, the recording plates A and B having been recorded from the drum 1 are received by the plate discharging unit 4 and discharged to the outside.
[0019]
FIG. 3 is a perspective view showing the recording unit shown in FIG. FIG. 4 is a perspective view of the recording unit shown in FIG. 3 when viewed from a reverse direction. In the recording unit 2, the recording plate A is wound and held around the drum 1. The drum 1 is rotated by a drum rotation motor 21, and the recording heads 22 and 23 run in the axial direction of the drum 1. Is recorded. The drum 1 is provided with clamp portions 25 and 26 for tightening and fixing the ends of the recording plate A, and a negative pressure groove 27 which is maintained at a negative pressure by a vacuum pump is provided on the outer peripheral surface of the drum 1. The recording plate A is closely fixed to the outer peripheral surface of the drum 1.
[0020]
The first and second recording heads 22 and 23 are provided with focus motors (position correcting means) 31 and 32 for correcting the positions in the optical axis direction, and carriages (first and second traveling units 33 and 34) of the first and second traveling units 33 and 34, respectively. Trolleys) 35 and 36. The second traveling unit 34 is provided with a distance sensor 38 for detecting a distance in the optical axis direction from the outer peripheral surface of the drum 1. The position of the distance sensor 38 is adjusted by the focus motor 32 integrally with the recording head 23.
[0021]
The carriages 35 and 36 of the first and second traveling units 33 and 34 are moved along a guide rail 41 by a linear motor mechanism, and a linear scale 42 for allowing a linear encoder provided on the carriages 35 and 36 to detect a position. Are provided along the guide rail 41.
[0022]
After being positioned at a predetermined recording start position, the first and second traveling units 33 and 34 perform recording on the recording plate A while moving in the axial direction (sub-scanning direction) in the recording area shared by each. At this time, each time the scanning in the main scanning direction by the rotation of the drum 1 is completed, control is performed to move the traveling units 33 and 34 in the sub-scanning direction by a predetermined amount. In the case of a multi-beam system in which a plurality of light sources are provided in the recording heads 22 and 23, the recording head moves in the sub-scanning direction by the number of lines to be simultaneously recorded.
[0023]
In order to attach the recording plate A to the drum 1, the recording plate A is fed toward the front end side clamp portion 25, the front end portion of the recording plate A is fixed by the front end side clamp portion 25, and the drum 1 is moved in a required direction. After the recording plate A is wound around the drum 1 by rotating, the rear end of the recording plate A may be fixed by the rear end side clamp portion 26. In order to remove the recording plate A from the drum 1, the fixing of the rear end side clamp portion 26 is released, the recording plate A is rotated in the opposite direction to feed the recording plate A toward the plate discharging portion, and then the front end side clamp portion 25 is released. Then, the recording plate A may be drawn into the plate discharging section.
[0024]
FIG. 5 is a block diagram showing a main configuration of the image recording apparatus shown in FIG. Here, a sensor input unit 52 to which the output signals of the distance sensor 38 and the drum position sensor 51 for detecting the rotation position of the drum 1 are input, a drum motor control unit 53 for controlling the operation of the drum rotation motor 21, A recording control unit 55 for controlling the motor 54, the recording heads 22 and 23, and the focus motors 31 and 32, a clamp control unit 56 for controlling the operations of the clamp units 25 and 26, and a plate for controlling the feeding and discharging of the recording plate A feed / discharge control unit 57, an interface 59 for connecting to a host (external computer) 58, an operation unit 60, a main control unit (arithmetic means) 61 for controlling these units, and control required here. It has a memory (storage means) 62 for storing information, and a measurement control unit 63 for operating the distance sensor 38 to measure the separation distance. The host 58 constitutes a higher-order plate making system, and generates and stores image data and plate information to be recorded on a recording plate.
[0025]
In this image recording apparatus, at the time of factory adjustment, installation of the apparatus, or maintenance, a focus table (position-specific correction information) relating to the fluctuation state of the separation distance according to the position on the drum 1 is created in advance and stored in the memory 62. At the time of recording, the recording controller 55 operates the focus motors 31 and 32 to correct the positions of the first and second recording heads 22 and 23 based on the focus table stored in the memory 62 during recording. Then, the recording heads 22 and 23 perform recording. The focus table is acquired by the measurement control unit 63 by causing the distance sensor 38 to measure the separation distance for a plurality of measurement points set on the outer peripheral surface of the drum 1.
[0026]
FIG. 6 shows a developed surface of the drum shown in FIG. A negative pressure groove 27 for adsorbing and fixing the recording plate is formed on a recording surface (plate mounting surface) 71 of the drum 1, and the negative pressure groove 27 is formed near the tip clamp 25. The negative pressure of the vacuum pump is introduced through the negative pressure introduction hole 72. The negative pressure grooves 27 are provided independently of each other in a plate mounting area corresponding to the standard width recording plate A so that two standard width recording plates A that can be mounted side by side on the drum can be fixed by suction alone. Have been.
[0027]
On the recording surface (plate mounting surface) 71 provided with the negative pressure grooves 27, in order to acquire a focus table (correction information for each position), the positions in the axial direction (sub-scanning direction) X1 to X18 and the circumferential direction ( A total of 162 measurement points defined by the positions (main scanning direction) Y1 to Y9 are set so as to avoid the negative pressure groove 27. The focus table is for setting a correction amount according to the axial position of the drum 1, and nine measurement points (Xn, Y1) to (Xn, Y9) arranged in the circumferential direction at the axial measurement position Xn. The median value of the nine measurement values obtained by the measurement for is the separation distance representing the measurement position Xn in the axial direction.
[0028]
The measurement point (Xn, Ym) is located at the center portion in the axial direction, that is, the measurement position X4 to X4 in the axial direction, as compared with both end portions in the axial direction of the drum 1, ie, the measurement positions X1 to X4 and X15 to X18 in the axial direction. The parts X9 and X10 to X15 are arranged so as to be dense.
[0029]
As shown in FIGS. 3 and 4, the drum 1 is formed in such a manner that the open portions at both ends of the cylindrical pipe-like member 44 are closed by a lid-like member 46 having a rotating shaft 45. Fluctuations in the separation distance are relatively small at both ends in the axial direction, which are solid, and fluctuations in the separation distance are relatively large, at the center portion in the hollow axial direction. Accordingly, highly accurate correction can be performed in detail corresponding to the change in the separation distance.
[0030]
FIG. 7 shows an example of a focus curve acquired in a measurement operation for the measurement points shown in FIG. The focus curve is drawn by plotting the separation distance for each measurement position Xn in the axial direction on coordinates with the horizontal axis as the axial position, and indicates the fluctuation state of the separation distance according to the axial position. Here, the measurement distance is obtained by converting a signal output from the distance sensor into a distance, but in reality, the output signal of the distance sensor is converted into the number of drive pulses of the focus motor, and the number of increase / decrease pulses relative to the reference position is obtained. That is, it is stored in the memory 62 as a position correction amount with respect to the reference position. The position correction amount (the number of increase / decrease pulses) is calculated in consideration of the offset amount between the optical axes of the recording heads 22 and 23 and the center axis of the distance sensor 38, and the measurement value of the linear scale 42.
[0031]
FIG. 8 shows a focus table acquired based on the focus curve shown in FIG. The position correction of the recording heads 22 and 23 is performed every time the traveling units 33 and 34 are moved in the sub-scanning direction after the recording in the main scanning direction is completed. Is obtained by the linear interpolation method from the respective correction amounts at the measurement position Xn and the adjacent measurement position Xn + 1, and stored in the memory 62 as a focus table (position-specific correction information). Note that the number of axial positions at which the correction amount is obtained by the linear interpolation method is determined according to the amount of movement of the traveling unit in the sub-scanning direction when scanning in the main scanning direction is completed. It differs depending on the distance between adjacent measurement positions Xn + 1.
[0032]
FIG. 9 is a flowchart showing a procedure for acquiring the focus table shown in FIG. Here, first, at step 101, the first traveling unit 33 is moved to a predetermined standby position so as not to hinder the measurement operation by the distance sensor 38 of the second traveling unit 34, and then at step 102, the distance sensor 38 The second traveling unit 34 is moved to a position matching the required measurement point (Xn, Ym), and the drum 1 is rotated in step 103 so that the distance sensor 38 faces the required measurement point.
[0033]
In step 104, the distance sensor 38 measures the separation distance from the outer peripheral surface of the drum 1 a predetermined number of times (for example, 10 times) with the distance sensor 38 as a reference position, and performs an operation to calculate the average of the measured values. And stored in the memory 62. Here, the average value is calculated for the measured values (for example, a total of six times) except for the predetermined number of times (for example, two times) on the maximum value side and the minimum value side of the measured values.
[0034]
This distance measurement operation is repeatedly performed until all the predetermined number of measurement points (here, nine points) arranged in the circumferential direction (main scanning direction) of the drum 1 are completed. If it is determined that the measurement has been completed, the measurement of the separation distance for the measurement point in the next column in the axial direction (sub-scanning direction) is performed, and the measurement points in all columns are completed in step 106. If so, the process proceeds to step 107. In step 107, a calculation for converting the separation distance indicated by the output of the distance sensor 38 into the number of pulses for driving the focus motor and obtaining the focus table by the linear interpolation method is performed.
[0035]
Further, as shown in FIG. 4, in this image recording apparatus, the first and second recording heads 22 and 23 can be appropriately recorded at the time of factory adjustment, apparatus installation, or maintenance. Is adjusted, the separation distance is measured for the reference point (X19, Y10) set on the blank surface (non-plate mounting surface) 73 of the drum 1, and the separation of the second recording head 22 is performed. An operation of acquiring the appropriate distance value P2 in advance is performed and stored in the memory 62.
[0036]
FIG. 10 shows an outline of pre-processing performed immediately before recording in the recording unit shown in FIG. At the time of recording, the positions of the recording heads 22 and 23 are corrected such that the distance between the first and second recording heads 22 and 23 with respect to the drum 1 is maintained at the appropriate values P1 and P2, respectively. The variation amount ΔP (correction information at recording) of the separation distance due to the change is considered, and the position correction is performed in a state where the correction amount of the focus table is uniformly corrected by the variation amount ΔP.
[0037]
Specifically, after adjusting the distance sensor 38 to the reference position, the measurement control unit 63 measures the separation distance for the reference point set on the blank surface 73 of the drum 1 to the distance sensor 38. Then, the measured value P thus obtained is compared with an appropriate value P2 (stored in the memory) of the second recording head 23 mounted on the second traveling unit 34 having the distance sensor 38, and the measured value P is compared with the measured value P. A fluctuation value ΔP (recording correction information) is acquired as a difference from the appropriate value P2.
[0038]
In the second recording head 23, as the second traveling unit 34 moves in the axial direction (sub-scanning direction), the focus curve shown in FIG. 7 is translated by an amount corresponding to the variation ΔP. The position is corrected so as to follow the curve, whereby the separation distance is maintained at the appropriate value P2. Also, in the first recording head 22, the separation distance is maintained at the appropriate value P1 by performing position correction so as to follow the focus curve translated in parallel by an amount corresponding to the variation ΔP.
[0039]
FIG. 11 is a flowchart showing the procedure of the pre-recording process shown in FIG. This pre-recording process is performed when the recording plate is removed and attached to the drum 1.
[0040]
First, in step 201, the second traveling unit 34 is moved to the axial measurement position (X19) corresponding to the reference point (X19, Y10) on the blank surface 73 by the distance sensor 38. Here, since the circumferential measurement position (Y10) coincides with the drum standby position, the distance sensor 38 can be directly opposed to the reference point without rotating the drum 1 in particular. Next, at step 202, the separation distance is measured by the distance sensor 38, and then at step 203, the measurement result is stored in the memory 62. In step 204, a calculation for calculating the variation ΔP is performed. In step 205, the position of the first recording head is corrected based on the variation ΔP. 2 The position of the recording head is corrected.
[0041]
FIG. 12 is a flowchart showing a procedure at the time of recording by the recording unit shown in FIG. Here, each time the recording unit in the main scanning direction is completed and the traveling units 33 and 34 are moved in the sub-scanning direction, it is determined whether or not the position correction operation of the recording heads 22 and 23 is necessary by referring to the focus table. .
[0042]
First, in step 301, a printing operation is performed on the printing plate in the main scanning direction. In step 302, when it is determined that there is no command indicating the end of the image data and printing is not finished, step 303 To obtain the correction amount of the next position with reference to the focus table. Then, in step 304, it is determined whether or not the correction process is necessary. Proceeding to 305, the traveling units 33 and 34 are moved to the next recording position, and the recording operation in the next main scanning direction is performed. On the other hand, if the correction processing is necessary, the flow proceeds to step 306 to move the traveling units 33 and 34 to the next recording position, and at step 307 the recording is performed by operating the focus motors 31 and 32 according to the correction amount. After moving the heads 22 and 23, the next recording operation in the main scanning direction is performed.
[0043]
【The invention's effect】
As described above, according to the present invention, since the position correction of the recording head is performed based on the fluctuation state of the correction amount according to the position on the drum, sufficient accuracy for practical use is ensured even in a traveling unit without a distance sensor. Therefore, it is not necessary to separately provide a distance sensor for a plurality of traveling units, and a great effect can be obtained in suppressing an increase in manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a front view showing an entire image recording apparatus according to the present invention; FIG. 2 is a side view of the image recording apparatus shown in FIG. 1; FIG. 3 is a perspective view showing a recording unit shown in FIG. FIG. 5 is a perspective view of the recording unit shown in FIG. 3 viewed from the opposite direction. FIG. 5 is a block diagram showing a main configuration of the image recording apparatus shown in FIG. 1. FIG. FIG. 7 is a diagram showing an example of a focus curve acquired in a measurement operation for the measurement points shown in FIG. 6; FIG. 8 is a focus acquired based on the focus curve shown in FIG. FIG. 9 is a flowchart showing a procedure for acquiring the focus table shown in FIG. 8; FIG. 10 is a diagram showing an outline of position correction of a print head performed immediately before printing in the printing unit shown in FIG. FIG. 11 is a flowchart showing the procedure of the pre-recording process shown in FIG. Flow diagram showing a recording time of the procedure of the recording unit shown in FIG. 3 [Description of symbols]
1 Drum 2 Recording units 22 and 23 Recording heads 31 and 32 Focus motors 33 and 34 Traveling unit 38 Distance sensor 41 Guide rail 44 Cylindrical pipe member 45 Rotating shaft 46 Cover member 54 Linear motor 55 Recording control unit 61 Main control unit ( Arithmetic means)
62 memory (storage means)
63 Measurement control unit A / B Recording plate

Claims (4)

A drum around which the recording plate is wound,
A recording head that irradiates the recording plate with light for exposure, and a position correction unit that corrects the position of the recording plate in the optical axis direction, and a plurality of traveling units that can travel in the axial direction of the drum along the same guide rail. ,
A distance sensor mounted on any of the plurality of traveling units to measure a separation distance in an optical axis direction with respect to an outer peripheral surface of the drum;
Storage means for storing position-specific correction information relating to the fluctuation state of the correction amount according to the position on the drum, which is obtained in advance by the measurement operation by the distance sensor,
A recording control unit for causing the recording head to perform recording while correcting the position of the recording head by the position correction unit based on the position-specific correction information stored in the storage unit. apparatus. At the time of recording, measurement control means for causing the distance sensor to measure the separation distance for a reference point set on the outer peripheral surface of the drum,
Calculating means for acquiring recording-time correction information regarding a variation amount of the separation distance caused by an environmental change based on a measurement result of the separation distance by the measurement control means,
2. The image recording apparatus according to claim 1, wherein the recording control unit corrects the position of the recording head based on the recording correction information. The storage unit further obtains an appropriate value relating to the traveling unit including the distance sensor, which is obtained in advance by a measurement operation of the separation distance with respect to the reference point in a state adjusted so that an appropriate image can be recorded. Remember,
The method according to claim 1, wherein the calculating unit compares a measurement value obtained at the time of recording by the measurement control unit with an appropriate value in the storage unit to calculate a variation amount due to the environmental change. 3. The image recording device according to 2. The drum is formed in such a manner that the open portions at both ends of the cylindrical pipe-shaped member are closed by a lid-shaped member having a rotating shaft, and is set on an outer peripheral surface of the drum to acquire the position-specific correction information. 2. The image recording apparatus according to claim 1, wherein the plurality of measurement points are arranged such that a central portion in the axial direction is denser than both end portions in the axial direction of the drum. 3.

Images