JP2012091362A - Image recording apparatus and method for correcting image recording position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus and method for correcting an image recording position that can detect periodical variations of a conveyance state of a recording medium in an especially simple configuration and can achieve quality image recording by correction of the image recording position, wherein the image recording apparatus and the method for correcting the image recording position detects the position of the recording medium and corrects the position where images are formed.SOLUTION: The image recording apparatus for recording images on the recording medium includes: a medium position detection means for detecting the position of the recording medium; a storage means for storing position information of the recording medium detected by the medium position detection means; a correction means for correcting the recording position on the recording medium based on the position information of the recording medium stored in the storage means; and a recording means for recording at a position of the recording medium where the recording position is corrected by the correction means.

Description

  The present invention relates to an image recording apparatus that records an image by fixing ink on a recording medium, and more particularly to an image recording apparatus and an image recording position correction method that detect the position of the recording medium and correct the image recording position.

  2. Description of the Related Art Image recording apparatuses that wind a large amount of paper, film, or the like in a roll shape and record an image on a continuous recording medium are known. For example, an image recording apparatus that records a color image by sequentially ejecting ink of four colors of K (black), C (cyan), M (magenta), and Y (yellow) onto the continuous recording medium.

  Such an image recording apparatus performs image recording while conveying a recording medium at a high speed of, for example, several tens to several hundreds of m / min. Further, the recording medium (continuous paper) on which image recording is performed is cut and discharged for each page. When the recording medium wound in the roll shape as described above is transported and image recording is sequentially performed by the recording heads of a plurality of colors, if the transport position or transport direction of the recording medium fluctuates, the position of each color on which the image is recorded is changed. A slight error occurs and the quality of the recorded image is lowered.

  For example, Patent Documents 1 and 2 have been proposed as inventions that suppress the quality degradation of the recorded image. For example, Patent Document 1 discloses an invention that corrects skew of a recording medium by a mechanical mechanism, obtains a skew angle of continuous paper based on detection results of two line sensors, and the skew angle is a desired angle. By adjusting the roller angle and the nip pressure so as to be as follows, the conveyance direction of the continuous paper is straightened, and the printing position deviation is suppressed.

  Further, Patent Document 2 detects a skew state of a continuous sheet by two photo sensors, calculates a skew amount of a recording medium by a control unit, and based on the skew information, the position of a print head, a light emitting element The color misregistration is corrected by controlling the position and the amount of light.

Japanese Patent Laid-Open No. 2007-70089 JP 2006-91384 A

  A continuous recording medium is usually wound in a roll shape, and the conveyance position changes in a direction perpendicular to the periodic recording medium conveyance direction with the outer periphery of the roll as a cycle, depending on the processing state of the roll and the mounting state of the roll. That is, a periodic fluctuation such as a sine wave is generated instead of being linear.

  However, in the apparatus of Patent Document 1, since the skew of the recording medium is corrected by a mechanical mechanism, the conveyance state of the recording medium that changes slowly and gradually can be corrected, but short cycle fluctuations cannot be corrected. .

  Further, in the apparatus of Patent Document 2, since the skew state of the recording medium is detected and corrected by the two photosensors, only a linear variation can be corrected. It cannot be corrected.

  Further, since correction is performed according to the detected state, a time lag occurs between the detected moment and the time when the correction is applied, and a phase difference occurs with respect to periodic fluctuations, so that appropriate correction cannot be performed.

  The present invention has been made in view of the above problems, and can detect high-quality image recording by detecting periodic fluctuations in the conveyance state of the recording medium and correcting the image recording position with a simple configuration. It is an object to provide an image recording apparatus and an image recording position correction method.

  In order to achieve the above object, an image recording apparatus according to an aspect of the present invention includes a medium position detecting unit that detects a position of a recording medium, and a storage that stores position information of the recording medium detected by the medium position detecting unit. Means, correction means for correcting the recording position on the recording medium based on position information of the recording medium stored in the storage means, and recording means for recording at the position of the recording medium whose recording position has been corrected by the correction means It is characterized by having.

  An image recording position correction method according to another aspect of the present invention includes a medium position detection process for detecting a position of a recording medium, and storage medium position information detected by the medium position detection process. Processing for correcting the recording position on the recording medium based on the recording medium position information stored in the storage means, and recording processing for recording at the position of the recording medium whose recording position has been corrected by this correction processing It is characterized by performing.

  According to the present invention, with respect to periodic fluctuations depending on the roll diameter, the recording medium position for each recording head is calculated from the recording medium position data detected by the medium position detecting means, and it corresponds to a non-linear periodic change. In addition, the present invention provides an image recording apparatus and an image recording position correction method for correcting an image recording position without delay and realizing high-quality image recording.

It is a functional block diagram of the image recording device in the present embodiment. 1 is a configuration diagram of an image recording apparatus centering on a medium transport mechanism in the present embodiment. It is a figure which shows the circuit structure of an image information processing part. (A) is a figure which shows the cross-sectional structure of the recording medium wound by roll shape, (b) is the state by which the recording medium and the paper tube were correctly processed, and were attached to the axis | shaft as designed. (C) is a diagram showing a state in which the recording medium is wound around the paper tube in an inclined manner, and (d) is a diagram in which the inner diameter of the paper tube is large and there is a gap between the shaft and the shaft. FIG. 6 is a diagram illustrating a state in which a recording medium is attached with an inclination with respect to an axis. It is a figure explaining the position correction method of the main scanning direction in this embodiment. It is a flowchart explaining the calculation of a correction value, and the writing process to memory. 6 is a flowchart for explaining position correction and print data generation processing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the following description, as the image recording apparatus of the present embodiment, a fixed line type recording head having a nozzle row length (image recording width) equal to or larger than the width of the recording medium is mounted and conveyed and passes directly below the nozzles. An example of an image recording apparatus that records an image on a recording medium will be described. Note that the image recording apparatus of the present embodiment is not limited to the image recording apparatus of the line type recording head, and other types of image recording apparatuses such as a scanning type can be applied to an inkjet type image recording apparatus. Also good.

FIG. 1 is a functional block diagram of the image recording apparatus according to the present embodiment, and FIG. 2 is a configuration diagram of the image recording apparatus according to the present embodiment, centering on a medium transport mechanism. In the following description, the conveyance direction of the recording medium is the sub-scanning direction, and the direction orthogonal to the sub-scanning direction is the main scanning direction.
The image recording apparatus 1 includes a control unit 2, a recording unit 3, a medium position detecting unit 4, a roll diameter measuring unit 5, a medium conveying mechanism 6, and the like, and a host device 7 is connected via a LAN (Local Area Network) or the like. ing. The host apparatus 7 is a host device such as a personal computer (PC), and transmits job information to the image recording apparatus 1. The job information is information including, for example, a command for instructing execution of recording processing, image data, various control commands, and the like, and is transmitted in a format such as Post Script (registered trademark).

  The image recording apparatus 1 receives the job information transmitted from the host apparatus 7, ejects ink onto the recording medium 8 based on the image data included in the job information, and records an image on the recording medium 8.

  The control unit 2 includes, for example, an MPU (Micro Processor Unit) having a control function and an arithmetic function, a ROM (Read Only Memory) storing a control program, a RAM (Random Access Memory) serving as an MPU work memory, and the like. And at least a non-volatile memory that stores setting values relating to control of the image recording apparatus 1.

  The MPU can control each component of the image recording apparatus 1 by executing a predetermined control program. The control unit 2 includes a storage unit 13 that has a function of processing image information by the image information processing unit 12 and stores data for image recording and the like by executing a predetermined control program by the MPU.

  The image information processing unit 12 develops image data for image recording in the storage unit 13 based on the job information sent from the host device 7. The interface unit 14 is an interface for transmitting / receiving data such as job information and signals to / from the host device 7.

  The storage unit 13 is also used as a RAM. Further, the nonvolatile memory also stores information such as parameters used for recording defect inspection. Note that the image information processing unit 12 can also be configured as a processing circuit (hardware) controlled by the MPU.

  The control unit 2 configured as described above receives the job information transmitted from the host device 7 and executes a predetermined control program, thereby causing the medium transport mechanism 6, the front surface recording unit 3 </ b> A, and the back surface recording unit 3 </ b> B to Then, image recording processing on the recording medium 8 is performed by controlling the medium position detecting unit 4 and the roll diameter measuring unit 5 respectively.

  The medium transport mechanism 6 has a function of transporting the recording medium 8 from the transport upstream side to the downstream side. The medium transport mechanism 6 includes a medium feeding unit 16, a front surface medium support unit 17A, a back surface medium support unit 17B, a drive unit 18, and a medium transport information generation unit 19.

  The medium feeding unit 16 rotatably supports a shaft 9 shown in FIG. 2 on a stand (not shown), and holds the recording medium 8 wound around the paper tube 10 on the shaft 9. The recording medium 8 is, for example, paper or film, is a continuous paper having a predetermined width, and is formed in a roll shape. Further, the medium feeding unit 16 applies a constant tension to the recording medium 8 by applying a load to the rotation of the recording medium 8 wound in a roll shape according to an instruction from the control unit 2, and the recording medium 8 being conveyed. Prevent slack.

The drive unit 18 includes a power source, for example, a motor and a roller. The drive unit 18 is driven by an instruction from the control unit 2 and rotates the roller to convey the recording medium 8.
The front surface medium support portion 17A and the back surface medium support portion 17B are rotatable cylindrical members that are in close contact with the recording medium 8 and rotate in conjunction with the conveyance of the recording medium 8. Further, the front surface medium support portion 17A and the rear surface medium support portion 17B are provided opposite to the corresponding front surface recording portion 3A and back surface recording portion 3B, and stabilize the position and posture of the recording medium 8 during the recording process. Let

  The medium conveyance information generation unit 19 is constituted by, for example, a rotary encoder, and is provided on the back surface medium support member 17B as shown in FIG. The medium conveyance information generation unit 19 generates a pulse signal corresponding to the rotation amount of the back surface medium support member 17B, that is, the conveyance amount (movement amount) of the recording medium 8, and transmits the pulse signal to the control unit 2.

  For example, K (black), C (cyan), M (magenta), and Y (yellow) recording heads 20-1 to 20-4 are disposed in the front surface recording unit 3A. These recording heads 20-1 to 20-4 are arranged substantially parallel to the sub-scanning direction in the order of K, C, M, Y from the upstream side of the conveyance path of the recording medium 8. Similarly, recording heads 20-5 to 20-8 for each color of K, C, M, and Y are disposed in the back surface recording unit 3B, and K, C, M from the upstream side of the conveyance path of the recording medium 8 are disposed. , Y are arranged in substantially parallel to the sub-scanning direction.

  Each recording head 20-1 to 20-8 has a resolution of 300 dpi, for example. When the front surface recording unit 3A and the back surface recording unit 3B receive an instruction to execute a recording process from the control unit 2, the recording medium 8 is recorded at a predetermined timing in synchronization with the pulse signal generated by the medium conveyance information generating unit 19. Perform the recording process above.

  That is, the front surface recording unit 3A and the back surface recording unit 3B eject inks of respective colors K, C, M, and Y from a plurality of nozzles in the recording heads 20-1 to 20-8, respectively, and thereby record the recording medium 8. Images, characters, etc. are recorded on the top.

  On the other hand, the medium position detection unit 4 is composed of a one-dimensional sensor such as a line sensor camera or a contact image sensor, and receives light reflected from the recording medium 8 from a light source built in the sensor or provided separately. Then, the photoelectrically converted electrical signal is transmitted to the control unit 2. The control unit 2 determines the main scanning direction position of the recording medium 8 from the received electrical signal, the image information processing unit 12 determines the image forming position corresponding to the main scanning direction position of the recording medium 8, and the surface recording The image data is transmitted to the unit 3A and the back surface recording unit 3B.

  The medium cutting unit 28 cuts the recording medium 8 on which the recording process has been performed into a standard paper size such as A4, A3, letter, tabloid, or a predetermined size in accordance with an instruction from the host apparatus 7.

  The medium discharge unit 29 has a pair of rollers that are driven to rotate, and discharges the cut recording medium 8 to the outside of the apparatus. Further, the medium recovery unit 30 aligns the stacked recording media 8 that have been cut to a predetermined size, and holds them in a stacked state.

  The roll diameter measuring unit 5 measures the radius of the roll paper that gradually decreases as the recording medium 8 is conveyed. The roll diameter measuring unit 5 uses, for example, a sensor capable of measuring a distance by a laser. The roll diameter measuring unit 5 is composed of an encoder attached to the shaft 9 of the medium feeding unit 16, and roll paper is calculated from the rotational speed of the shaft 9 and the conveyance speed of the recording medium 8 measured by the medium conveyance information generating unit 19. The radius may be calculated.

  Next, FIG. 3 is a diagram showing a circuit configuration of the image information processing unit 12 described above. The conveyance speed calculation unit 22, the write pointer control unit 23, the read pointer control unit 24, the calculation unit 25, the memory 26, and the recording data. The generation unit 27 is configured.

  The conveyance speed calculation unit 22 receives the pulse signal generated and transmitted by the medium conveyance information generation unit 19 described above, and calculates the conveyance speed of the recording medium 8. The light pointer control unit 23 receives the data on the conveyance speed from the conveyance speed calculation unit 22 and also receives the data on the radius of the roll paper around which the recording medium 8 is wound from the roll diameter measurement unit 5. Then, the length of one round of the roll paper is calculated using the data of the conveyance speed and the radius of the roll paper, the write pointer Pw which is the write address of the write pointer control unit 23 is set, and the position information to the memory 26 is set. The write address is used.

  Further, the read pointer control unit 24 sets a read address (read pointer Pr) according to path length data based on the arrangement positions of the recording heads 20-1 to 20-8 described later, and the position information written in the memory 26. Read processing is performed.

The recording data generation unit 27 performs position correction processing of the image data transmitted from the host device 7 based on position data (hereinafter, referred to as position correction data) B1 to B8 read from the memory 26, and records the image data. It is a circuit that outputs to the heads 20-1 to 20-8.
Next, changes in the position in the main scanning direction caused by the processing accuracy of the recording medium 8 wound in a roll shape will be described with reference to FIG.

  FIG. 4A is a diagram showing a cross-sectional configuration of the recording medium 8 wound in a roll shape. As described above, the recording medium 8 is attached to the paper tube 10 fixed to the shaft 9 rotatably supported. It is wound. FIG. 5B shows a state where the recording medium 8 and the paper tube 10 are correctly processed and attached to the shaft 9 as designed.

  On the other hand, FIG. 3C shows a state in which the recording medium 8 is wound around the paper tube 10 at an angle. Note that the radius of the roll paper as the recording medium 8 at this time is R, and the maximum shift amount in the main scanning direction due to the winding inclination is X. In this case, the position in the main scanning direction of the recording medium 8 transported inside the image recording apparatus 1 varies with the amplitude of the distance X when the roll paper advances one revolution (2πR).

  FIG. 4D shows a state in which the inner diameter of the paper tube 10 is large and there is a gap between the shaft 9 and the recording medium 8 is attached to the shaft 9 with an inclination. At this time, the radius of the roll paper as the recording medium 8 is R, and the maximum deviation amount in the main scanning direction due to the winding inclination is X. In this case as well, as in the case described with reference to FIG. 5C, the position in the main scanning direction of the recording medium 8 conveyed inside the image recording apparatus 1 is the distance X when the roll paper advances one revolution (2πR). Fluctuates with amplitude.

  FIG. 5 shows the arrangement positions of the respective components of the image recording apparatus 1 provided on the conveyance path of the recording medium 8, and the cyclic positional deviation state of the recording medium 8 in the sub-scanning direction with respect to the arrangement positions. Show. Note that a path P on the conveyance path of the recording medium 8 shown in the figure indicates the path of the edge position of the recording medium 8 in the main scanning direction.

  Further, T shown in the figure is a design target position, and indicates a path through which the edge position of the recording medium 8 should pass. Further, the path P shown in the figure is an example in which the actual edge position of the recording medium 8 is plotted, and the average value of the path P is derived from the installation of the roll paper and the like from the design target position T. It is a value offset by A shown in the figure. The path P includes a fluctuation component of an amplitude X and a period of 2πR because the roll diameter period varies due to the processing of the roll paper described with reference to FIG.

Next, the position correction process of the image data in the main scanning direction by the image information processing unit 12 will be described.
The medium position detection unit 4 detects the position of the recording medium at the same cycle as the recording process by the recording heads 20-1 to 20-8. For example, when the conveyance speed V of the recording medium 8 is 565 mm / s and the printing resolution is 300 dpi, the printing cycle t is obtained by the following equation (1).

The detection cycle by the medium position detection unit 4 is the same as the printing cycle t and is 150 μs.
When the maximum roll radius Rmax allowed by the medium feeding unit 16 is 686 mm, the memory 26 needs to have an address space represented by the following expression (2).
Therefore, as the memory 26 in this case, for example, a memory having a 64K address space is used.

  The conveyance speed calculation unit 22 receives the above-described encoder pulse from the medium conveyance information generation unit 19 and calculates the conveyance speed V. The data of the conveyance speed V is transmitted to the write pointer control unit 23.

The write pointer control unit 23 increments the address every time the medium position data is written at a cycle of 150 μs. The write pointer control unit 23 receives the roll radius information R from the roll diameter measurement unit 5 and the conveyance speed information V from the conveyance speed calculation unit 24. The write pointer is expressed by the following equation (3). If this value is exceeded, the write pointer is reset (“0”).

As a result, the memory 26 forms a ring buffer corresponding to one round of the roll diameter, and medium position data for one cycle corresponding to the roll diameter is held in the memory 26.
The read pointer control unit 24 manages pointers Pr1 to Pr8 indicating medium position correction data B1 to B8 corresponding to the recording heads 20-1 to 20-8, and a pointer of Pr9 indicating the same position as the write pointer.

The medium position data L0 read out by the pointer Pr9 is data that is past one roll paper from the medium position data L1 detected by the medium position detector 4. The calculation unit 25 calculates the medium position data L to be written in the memory 26 from the past medium position data L0 and the newly detected medium position data L1, using the following equation (4).

  Note that K is a preset constant. By setting K to a small value, it follows a steep roll diameter variation, but becomes sensitive to noise, and by setting K to a large value, it changes gently. . When K is set to 0, L = L1, and the value detected by the medium position detection unit 4 is written in the memory 26 as it is without the influence of the value detected in the past.

  The read pointer control unit 24 determines each recording head 20 based on the physical distances d1 to d8 between the recording heads 20-1 to 20-8 and the medium position detecting unit 4 in the conveyance path of the recording medium 8 and the address indicated by the write pointer. The pointers corresponding to -1 to 20-8 are calculated.

The pointers Pr1 to Pr4 are calculated by the following equation (5) because the recording heads 20-1 to 20-4 are located upstream of the medium position detection unit 4 on the transport path.

Further, since the recording heads 20-5 to 20-8 are positioned downstream of the medium position detection unit 4 on the transport path, the pointers Pr5 to 8 are calculated by the following equation (6).

  Further, when the calculated values of the pointers Pr1 to 8 are less than 0 or exceed the maximum address of the ring buffer calculated by the write pointer control unit 23, the maximum address value of the ring buffer is added or subtracted to determine which pointer Is also calculated to indicate the address in the ring buffer.

  Next, the processing operation of the image information processing unit 12 shown in FIG. 3 will be described using the above calculation formula and the flowchart shown in FIG.

  First, the write pointer control unit 23 sets the write pointer Pw to “0”, and the read pointer control unit 24 sets the read pointer Pr9 to “0” (step (hereinafter referred to as S) 1). That is, the write pointer control unit 23 and the read pointer control unit 24 perform initial setting of each pointer.

  Next, medium position information is acquired from the medium position detector 4 (S2). That is, the drive unit 18 is driven, the recording medium 8 is fed from the medium feeding unit 16, and the leading end position of the recording medium conveyed on the conveyance path is detected. Specifically, the edge position of the recording medium 8 conveyed on the conveyance path is detected by a sensor provided in the medium position detection unit 4. The edge position data is a.

  Next, data b is read from the memory 26 (S3), a write value is calculated from the data b and the position data a, and the calculation result is written to the memory 26 (S4). That is, new medium position data to be written in the memory 26 is calculated from the past medium position data L0 and the newly detected medium position data L1 by using the calculation formula (4) by the above-described arithmetic unit 25.

  Next, the write pointer control unit 23 acquires roll diameter data c from the roll diameter measurement unit 5, further acquires medium conveyance speed information d from the medium conveyance information generation unit 19, and obtains the maximum address from the data of c and d. Is calculated (S5 to S7). That is, the maximum address e required for the memory 26 is calculated using the above-described calculation formula (3).

  Next, the write pointer Pw and the read pointer Pr9 are incremented (+1), the pointer value f is obtained (S8), and the pointer value f is compared with the value of the maximum address e (S9). Here, when the pointer value f is larger than the maximum address e (S9 is YES), the write pointer Pw and the read pointer Pr9 are reset. In this first process, the pointer value f is smaller than the maximum address e (S9 is NO). ), It is determined whether the printing process is completed (S10).

  Thereafter, the above processing (S10 is NO, S2 to S10) is repeated, the corresponding past position data b is read from the memory 26, and the position data a detected by the medium position detection unit 4 is used to calculate the above formula ( In step 4), new medium position data is written in the memory 26. Therefore, by repeating the above processing, for example, the position data of the path P shown in FIG. Further, the route is updated to the path P based on the new position data detected by the medium position detection unit 4 according to the calculation formula (4).

  During this time, the judgment of comparing the pointer value f with the value of the maximum address e is also executed (S9). For example, when the pointer value f exceeds the maximum address e (S9 is YES), the write pointer Pw and the read pointer Pr9 are set. Reset is performed (S11). That is, the write pointer Pw is set to “0”, the read pointer Pr9 is set to “0”, and the above processing is repeated.

  During this time, image data is transmitted from the host device 7 to the memory 26, and recording data generation processing is performed by the recording data generation unit 27. FIG. 7 is a flowchart for explaining the above processing. When image data is acquired from the host device 7 (step (hereinafter referred to as ST) 1), image data for each of the recording heads 20-1 to 20-8 is generated ( ST2). That is, in the present embodiment, recording heads 20-1 to 20-4 for each color of K (black), C (cyan), M (magenta), and Y (yellow) are used for the front surface recording unit 3A, and the back surface The recording unit 3B uses recording heads 20-5 to 20-8 for each color of K, C, M, and Y, and generates image data for each of the recording heads 20-1 to 20-8 for each color. .

  Next, the read pointers Pr1 to Pr8 for each of the recording heads 20-1 to 20-8 are calculated (ST3). This calculation is performed according to the above formulas (5) and (6). For example, since the recording heads 20-1 to 20-4 are located upstream of the medium position detection unit 4 on the transport path, the formula ( 5) is used to calculate the corresponding read pointers Pr1-Pr4. Further, since the recording heads 20-5 to 20-8 are located downstream of the medium position detection unit 4 on the transport path, Expression (6) is used and corresponding read pointers Pr5 to Pr8 are calculated. The

  Next, the correction position data (B1 to B8) is read from the memory 26 for each of the recording heads 20-1 to 20-8 (ST4). That is, the read pointer control unit 24 reads the correction position data indicated by the calculated addresses of the read pointers Pr1 to Pr8 in the memory 26 and offsets the recording position in the main scanning direction (ST5).

  For example, based on the output address of the read pointer Pr1, the correction position data B1 is read from the memory 26, and the output position of the recording head 20-1 with respect to the recording data is offset. By this processing, the recording head 20-1 shifts the recording position in the main scanning direction of the recording medium 8 immediately below the recording head 20-1 by B1 (offset), and records an image at an accurate position on the recording medium 8. (ST6).

  Similarly, the recording head 20-2 also reads the correction position data B2 from the memory 26 based on the output address of the read pointer Pr2 (ST4), and offsets the output position of the recording head 20-2 with respect to the recording data (ST5). ). By this processing, the recording head 20-2 shifts the recording position in the main scanning direction of the recording medium 8 immediately below the recording head 20-2 by B2 (offset), and records an image at an accurate position on the recording medium 8. (ST6).

  In the same manner, for the recording heads 20-3 to 20-8, the corrected position data B3 to B8 are read from the memory 26 based on the output addresses of the corresponding read pointers Pr3 to Pr8, and the corresponding recording head 20- The output position with respect to the recording data 3-20-8 is offset, and the recording position in the main scanning direction of the recording medium 8 immediately below the corresponding recording head 20-3-20-8 is shifted by B3-B8 (offset). Image recording can be performed at 8 accurate positions.

  Thereafter, the above process is repeated until the printing process is completed (ST7 is NO, ST1 to ST7), and the image data recording process to the recording medium 8 is performed.

  On the other hand, recording processing of position data in the memory 26 based on the flowchart of FIG. 6 is also performed, and recording data generation processing by the recording data generation unit 27 based on the position data in the memory 26 that is sequentially updated. Is done. Therefore, the recording heads 20-1 to 20-8 offset the recording positions by B1 to B8 according to the main scanning direction position of the recording medium 8 immediately below the recording head, respectively, so that the main scanning with respect to the recording medium 8 is performed. Image recording can be performed at an accurate position in the direction.

  Thereafter, when the printing process ends (YES in S10 and YES in ST7), the writing process of the position data to the memory 26 and the recording data generating process by the recording data generating unit 27 are ended, and the printing process is ended.

As described above, according to the image recording apparatus 1 of the present embodiment, the recording position in the main scanning direction of the recording medium 8 by the setting position of the roll paper as the recording medium 8 is offset, resulting from the processing accuracy of the roll paper itself. A good image can be formed on the recording medium 8 by performing position correction corresponding to the position fluctuation in the main scanning direction of the roll paper outer shape cycle.
The memory 26 is empty until the roll paper as the recording medium 8 completes the first round. Meanwhile, the recording data generation unit 27 may use the output value L1 of the medium position detection unit 4 instead of the read values B1 to B8 from the memory 26.

  In the description of the above embodiment, the image recording apparatus adopting the ink jet recording method is described. However, the image recording apparatus can be applied to a method other than the ink jet method, for example, the image forming position correction in the main scanning direction in the electrostatic recording method. can do.

  The description of the present embodiment is an example of the present invention, and some elements may be deleted from the overall configuration shown in the image recording apparatus 1 of the present embodiment. You may combine suitably.

DESCRIPTION OF SYMBOLS 1 ... Image recording device 2 ... Control part 3 ... Recording part 3A ... Front surface recording part 3B ... Back side recording part 4 ... Medium position detection part 5 ... Roll diameter measurement part 6 ... Media transport mechanism 7 ... High-level device 8 ... Recording medium 9 ... Axis 10 ... Paper tube 12 ... Image information processing unit 13 ... Storage unit 14 ... Interface unit 16 ... Media feed Feed unit 17A... Medium support unit for front surface 17B... Medium support unit for back surface 18 .. Drive unit 19 .. Media conveyance information generation unit 20-1 to 20-8. ..Write pointer control unit 24..Read pointer control unit 25..Calculation unit 26..Memory 27..Record data generation unit 28..Medium cutting unit 29..Medium ejection unit 30..Medium recovery unit

Claims (10)

Medium position detecting means for detecting the position of the recording medium;
Storage means for storing position information of the recording medium detected by the medium position detection means;
Correction means for correcting the recording position on the recording medium based on the position information of the recording medium stored in the storage means;
Recording means for recording at a position of the recording medium whose recording position has been corrected by the correcting means;
An image recording apparatus comprising:   2. The image recording according to claim 1, wherein new position information detected by the medium position detection unit is calculated from the position information stored in the storage unit, and the calculation result is stored in the storage unit. apparatus.   A plurality of the recording means are provided with a predetermined interval for each color, and the correction means corresponds to an arrangement position of the plurality of recording means based on position information of the recording medium stored in the storage means. The image recording apparatus according to claim 1, wherein position information is read and a recording position on the recording medium is corrected.   The correction means reads position information corresponding to the recording position of the recording medium from the storage means in which position information of the recording medium is sequentially stored, and performs a main scanning on the recording position of the recording data based on the position information. The image recording apparatus according to claim 1, wherein the image recording apparatus corrects the direction.   The position information stored in the storage means is a portion of the roll paper around which the recording medium is wound, the diameter of the roll paper is measured by the measurement means, and the circumference of the roll paper is based on the measured value. The image recording apparatus according to claim 1, wherein the image recording apparatus is calculated. Medium position detection processing for detecting the position of the recording medium;
A storage process for storing in the storage means the position information of the recording medium detected by the medium position detection process;
Correction processing for correcting the recording position on the recording medium based on the positional information of the recording medium stored in the storage means;
A recording process for recording at a position of the recording medium whose recording position has been corrected by the correction process;
An image recording position correction method comprising:   7. The image recording according to claim 6, wherein new position information detected by the medium position detection process is calculated from the position information stored in the storage unit, and the calculation result is stored in the storage unit. Position correction method.   A plurality of the recording means are provided with a predetermined interval for each color, and the correction processing corresponds to an arrangement position of the plurality of recording means based on position information of the recording medium stored in the storage means. 8. The image recording position correcting method according to claim 6, wherein position information is read and the recording position on the recording medium is corrected.   The correction process reads position information corresponding to the recording position of the recording medium from the storage means in which position information of the recording medium is sequentially stored, and performs a main scanning on the recording position of the recording data based on the position information. The image recording position correction method according to claim 6, 7 or 8, wherein the image recording position is corrected in a direction.   The position information stored in the storage means is a portion of the roll paper around which the recording medium is wound, the diameter of the roll paper is measured by the measurement means, and the circumference of the roll paper is based on the measured value. The image recording position correction method according to claim 6, wherein the image recording position correction method is calculated.