JP2001171098A - Ink jet recorder and method for correcting shift of rule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct shift of a rule occurring at the time of bi-directional printing through automatic adjustment while taking account of satellite occurring at the time of image printing. SOLUTION: At a first speed actually used in printing, pattern elements 32', 31' spaced apart by a specified interval x of designated value along the moving direction of a head are reciprocated for printing and, at a sufficiently lower second speed, two pattern elements 32, 31 are reciprocated for printing. For a test pattern printed at the first speed, difference is determined between the detected interval y' of two pattern elements and the specified interval x of designated value and then the widths h1, h2' of the pattern elements printed at the first speed and the widths h1 h2 of the pattern elements printed at the second speed are detected and the difference thereof is determined. The difference of interval is then corrected by the difference of width to obtain a rule adjusting value. Ink ejecting position (timing) is corrected at the time of bi- directional printing based on the rule adjusting value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for forming an image on a recording medium such as plain paper or OHP paper by discharging ink from nozzles of a print head.

[0002]

2. Description of the Related Art As one of output devices such as a computer and a work station, there is known an ink jet recording apparatus which forms an image on a recording medium such as recording paper by discharging ink. This ink jet type recording apparatus usually includes a print head in which nozzle groups for ejecting ink are formed, a carriage mounting the print head and moving in a predetermined direction, and a direction orthogonal to the predetermined direction (recording medium conveyance). And a recording medium transport device that transports the recording medium in the direction (i.e., direction).

When an image is formed on a recording medium, the recording medium being conveyed by the recording medium conveying device is temporarily stopped, and the carriage is reciprocated in the above-mentioned predetermined direction, and the image is recorded on the basis of an image signal carrying image information. Ink from the nozzles to form an image for one band in an image forming area (band area) on the recording medium facing the ink discharge ports of the nozzle group. Next, the recording medium is conveyed by the width of one band and stopped, and again, while the carriage is reciprocated in the above-described predetermined direction, ink is ejected from the nozzle group based on the image signal to form an image on the recording medium. The entire image is formed in a new band area located in the area. By repeating such an operation, an image for one page is formed on the recording medium.

FIG. 1 shows a simple schematic diagram of such an ink jet recording apparatus.

In this ink jet recording apparatus, a plurality of heads each having an ink discharge port 17 are mounted on a carriage 15. The carriage 15 is supported so as to reciprocate in the main scanning direction along a guide (not shown). The reciprocating operation of the carriage 15 is performed by a belt 13 suspended on a pulley 12 driven to rotate by a stepping motor 11. An optical (photo) sensor unit 18 described later is mounted on the carriage 15.

A linear scale 14 is arranged along the scanning direction of the carriage 15, and a slit or the like is detected by a linear scale sensor 16. The linear scale sensor 16 is mounted on the carriage 15. The position (timing) of the ink ejection is managed mainly based on the output of the linear encoder including the linear scale 14 and the linear scale sensor 16. For example, when the carriage 15 passes a certain point on the linear scale 14, the ejection control of the ink is started, and when the carriage 15 passes a specific slit of the linear scale 14, the ejection of each color ink from the ink ejection port 17 is started. Do
Control is performed such that the ink discharge control is terminated at a point when a certain point on the linear scale 14 is passed.

As a problem in performing such ink ejection control, there is a ruled line shift in bidirectional printing. When printing a straight line extending in the direction perpendicular to the scanning direction of the carriage, the output image position when the carriage performs printing in the forward direction (for convenience, right to left) is determined by the position of the ink discharge port 17 and the sheet position, that is, the platen. 2A, the position 21 where the ink is discharged from the ink discharge port 17 does not match the position 22 where the ink actually lands on the paper, as shown in FIG. 2A. When the carriage discharges at the same position as the forward direction when the carriage performs printing in the backward direction (for convenience, from left to right), as shown in FIG. The ink landing position 23 is shifted. Hereinafter, for convenience, the prints in the forward direction and the backward direction are distinguished by the density in the figure.

FIG. 2 (c) is a combination of FIG. 2 (a) and FIG. 2 (b), and the total output image position in the forward and backward directions is d.
Only shifts. This is called ruled line shift in bidirectional printing. The deviation width of the ruled line differs depending on the speed of the carriage that performs printing, and the higher the speed, the larger the deviation width of the ruled line. This ruled line shift can be corrected by shifting the ejection position at the time of backward printing by d toward the negative side in the backward direction as shown in FIG.

Conventionally, as a means for correcting the deviation of the ruled line, a method of printing a ruled line adjustment pattern as a predetermined test pattern and manually inputting correction information by the user in accordance therewith, a method of printing a ruled line adjustment pattern, and There is a method in which a ruler line adjustment pattern is read by a photo sensor unit (18 in FIG. 1) attached to the printer and automatically adjusted.

As a conventional technique, an example of the automatic adjusting means will be described below.

As shown in FIG. 3, horizontal a (dot) × vertical b
The (dot) rectangular pattern elements 31 and 32 are printed in the same band in the forward direction and the backward direction by separating the ink discharge positions by an instruction value x (dot) of the linear scale interval. In this example, a is about 10 dots and x is 48
A dot size is assumed. Thereby, a parallel line pattern in which the center position of the pattern element is x dots away is obtained. In the illustrated example, the right pattern element 31 is printed in the forward direction, and the left pattern element 32 is printed in the backward direction.

FIG. 4A is a schematic diagram showing the state of this printing as viewed from the front of the carriage (from the direction of viewing the cross section of the paper).
It is. In the figure, 14 is a linear scale, 17 is an ink ejection port, 19 is a paper position (platen), 31 is an output image (pattern element) in the forward direction, and 32 is an output image (pattern element) in the backward direction. In the case of the pattern shown in FIG. 3, the interval between the pattern elements printed at the designated linear scale interval x (dot) is actually x for the reason described in FIG.
It becomes y (dot) smaller than (dot).

For this reason, the shift width xy (dot) is stored, and when printing in the backward direction, the xy (dot) backward direction (negative side) is printed.
By starting printing from a position shifted to the above, it is possible to align the ruled line.

The distance y (dot) between the pattern elements can be read by a photo sensor unit 18 attached to the carriage 15 or the like.

As a practical test pattern, taking into account the reading error of the optical sensor and the like, a plurality of prints are continuously printed as shown in FIG. 5, and the average value of correction values obtained from each parallel line pattern is obtained. May be used as the final correction value.

[0016]

However, as a problem of the automatic ruled line adjustment, there is a mistake in reading the optical sensor by the satellite. That is, after the ink is ejected from the head, the ink droplet draws a parabola, so that the ink dot 61 is formed at the actual ink landing point as shown in FIG. A small ink dot 62 is formed at a position slightly away from the ink dot. In this specification, the ink dots 61 are called main drops, and the ink dots 62 are called satellites.

Therefore, when a pattern element as shown in FIG. 3 is printed, the satellite actually scatters outside the downstream side in the scanning direction of the pattern element as shown in FIG. When such a pattern element is actually detected by the optical sensor, as shown schematically in FIG. 8, the center position of the actual pattern is obtained from the pattern interval y (dot) (a) assuming that there is no satellite. It is slightly shifted inward (b). Therefore, if the new pattern interval is (y ′ (dot)), y> y ′. Therefore,

(Xy) <(xy '), and the ruled line correction width is shifted. As described above, since the ink ejection position is shifted to the downstream side in the carriage scanning direction from the theoretical value, even if the correction is performed, as shown in FIG.
There is a problem in that the ruled line is shifted visually.

The present invention has been made in view of such a background, and a ruled line shift generated by bidirectional printing is automatically adjusted to take into account a satellite (described later) generated at the time of image printing and the like. It is an object of the present invention to provide an ink jet recording apparatus capable of adjusting an image so that a ruled line is visually matched, and a ruled line deviation correcting method thereof.

[0020]

An ink jet recording apparatus according to the present invention discharges ink from a plurality of nozzles of a print head while moving the print head along the recording medium to form an image for one band on the recording medium. In an ink jet recording apparatus for recording an entire image on a recording medium by repeating an operation of recording, transporting the recording medium by a predetermined amount and recording an image of the next one band, the print head moves by the print head. A test pattern printing means for printing at least two pattern elements separated by a predetermined distance along a direction by a predetermined value by forward printing and backward printing, respectively, and detecting the pattern elements while moving along a head moving direction Detecting means for determining an interval between the two pattern elements and a size of a satellite. A ruled line for calculating a ruled line adjustment value for adjusting a ruled line deviation between bands in bidirectional printing based on the actual pattern element interval and satellite size detected by the pattern detection means and the indicated value. An ink ejection position (timing) during bidirectional printing based on the adjustment value calculation means and the calculated ruled line adjustment value;
And an ink discharge position correcting means for correcting

That is, a test pattern capable of measuring the size of a satellite is printed and read by a sensor.
A ruled line adjustment value is calculated based on the value obtained therefrom. As a result, it is possible to correct a ruled line shift due to a satellite during bidirectional printing.

More specifically, the ink jet recording apparatus of the present invention discharges ink from a plurality of nozzles of the print head while moving the print head along the recording medium to form an image for one band on the recording medium. In an ink jet recording apparatus for recording an entire image on a recording medium by repeating an operation of recording, transporting the recording medium by a predetermined amount and recording an image of the next one band, the print head moves by the print head. A test pattern printing means for printing at least two pattern elements separated by a predetermined distance along a direction by a predetermined value by forward printing and backward printing, respectively, and detecting the pattern elements while moving along a head moving direction Pattern detecting means for determining a distance between the two pattern elements and a width of each pattern element. A ruled line adjustment value calculating means for calculating a ruled line adjustment value for adjusting a ruled line deviation between bands during bidirectional printing based on the detection result of the pattern detecting means, and a bidirectional line based on the calculated ruled line adjustment value. An ink discharge position correcting means for correcting an ink discharge position (timing) at the time of printing, wherein the ruled line adjustment value calculating means has a first speed used for actual printing and a second speed sufficiently lower than this; The first and second test patterns are printed by operating the test pattern printing means, and the test pattern printed at the first speed is subjected to the second test pattern.
A difference (hereinafter, referred to as an interval difference) between the detected interval of the pattern elements and the predetermined interval of the indicated value is obtained, and the width of the pattern element printed at the first speed and the second The width of a pattern element printed at a speed is detected, a difference (hereinafter, referred to as a width difference) is obtained, and a value obtained by correcting the interval difference with the width difference is used as a ruled line adjustment value.

[0023] The second speed is preferably such that no satellites are formed.

[0024] A means may be provided for further correcting the determined width difference according to the first speed. This allows
The calculation can be performed in consideration of the apparent ruled line shift caused by the satellite during the actual printing at the first speed. In other words, if the satellite becomes larger than a certain extent, the satellite will affect the ruled line deviation due to appearance, so rather than completely canceling the existence of the satellite, it is better to add the effect to the ruled line adjustment value to some extent, It works in the direction to eliminate the ruled line deviation. Actually, the size of the satellite varies depending on the magnitude of the first speed. Therefore, it is desirable to determine a coefficient for correcting the width difference according to the first speed experimentally or empirically.

According to the method of correcting ruled line misalignment of an ink jet recording apparatus according to the present invention, ink is ejected from a plurality of nozzles of a print head while a print head is moved along a recording medium, and an image for one band is recorded on the recording medium. In an ink jet recording apparatus that records the entire image on the recording medium by repeating the operation of transporting the recording medium by a predetermined amount and recording the image of the next one band, a ruled line between bands during bidirectional printing is used. A method of correcting misalignment, wherein the print head prints at least two pattern elements separated by a predetermined interval at a designated value along a head moving direction by forward printing and backward printing, respectively, Based on the output of a sensor that detects the pattern element while moving along the moving direction, the two pattern elements Septum and determining a magnitude of the satellite, the pattern interval of the actual pattern elements detected by the detection means and the satellite size,
Calculating a ruled line adjustment value for adjusting a ruled line shift between bands during bidirectional printing based on the designated value; and determining an ink ejection position during bidirectional printing based on the calculated ruled line adjustment value. (Timing) is corrected.

More specifically, in the method of correcting a ruled line shift of an ink jet recording apparatus according to the present invention, ink is ejected from a plurality of nozzles of a print head while moving the print head along the recording medium, and the ink is ejected onto the recording medium. In an ink jet printing apparatus that prints an entire image on a recording medium by repeating an operation of recording an image of the band, conveying the recording medium by a predetermined amount, and recording an image of the next one band, This is a method of correcting a displacement of a ruled line between bands at the time of printing. At a first speed used in actual printing, at least two pattern elements separated by a predetermined interval along a head moving direction by an indicated value are forwarded. Printing by directional printing and backward printing, and at a second speed, which is sufficiently lower than the first printing speed, at a designated value along the head moving direction. Printing at least two pattern elements separated by an interval by forward printing and backward printing, respectively, and for a test pattern printed at the first speed, the detected intervals of the two pattern elements; Detecting a predetermined interval of the indicated value and obtaining a difference (hereinafter referred to as an interval difference); a width of a pattern element printed at the first speed and a pattern printed at the second speed; Detecting the width of the element and calculating the difference (hereinafter referred to as the width difference); setting the corrected value of the interval difference by the width difference as a ruled line adjustment value; Correcting the ink ejection position (timing) during bidirectional printing based on the information.

According to these methods, the same operation and effects as those of the above-described device can be obtained.

[0028]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 15 is a schematic control block diagram of the plotter according to the embodiment of the present invention. The plotter according to the present embodiment includes a CPU 151 that controls the entire apparatus and an R that stores a control program and various data in a nonvolatile manner.
An OM 152 and a RAM 15 used as a work area used for processing by the CPU 151 and a temporary storage area for data.
3, a head controller 154 that sends an image signal carrying image information to the print head to control the ejection of ink from each nozzle, and a paper transport unit 15 that transports recording paper (paper).
5, a photo sensor 156 for detecting an image printed on recording paper, a clock unit 157 for counting the number of clocks based on a predetermined signal sent from the photo sensor 156 based on an instruction from the CPU 151, An operation unit 158 for performing various settings is provided. In the present embodiment, the clock counted by the clock unit 157 is a clock having a constant frequency higher than a signal obtained from the linear scale sensor 16 obtained at a normal printing speed.

FIG. 16 is a schematic diagram of a photosensor provided in the plotter of the present embodiment. The photo sensor 156 of the present embodiment is the same as the photo sensor unit 18 shown in FIG.
Is provided on the carriage 15. The photo sensor 156 is a so-called reflection type photo sensor having a light emitting unit 161 and a light receiving unit 162. Recording paper 16
3, the ruled line adjustment pattern described with reference to FIG. 3 and the like is printed. The light emitted by the light emitting unit 161 is applied to the recording paper 16.
2 and is received by the light receiving section 162. In this configuration, while scanning the carriage 15 at a predetermined speed, the position of each pattern element of the ruled line adjustment pattern on the recording paper 163 is detected by detecting the amount of reflected light in the non-printing portion and the printing portion. The photosensor 156 is configured so that the higher the density of the image, the higher the output potential.

FIG. 17 is a diagram showing an example of the output signal waveform of the photo sensor 156. The vertical axis in FIG. 17 shows the output potential [E] of the photosensor 156, and the horizontal axis shows time [T].
Is taking. The potential E2 is a threshold voltage, a portion higher than this is a signal from a printing portion, and a portion lower than this is a signal from a recording paper portion. T1 is a point where the white paper portion changes to a print portion during scanning, and T3 is a boundary point where the print portion changes to a white paper portion. The image portion between T1 and T3 corresponds to the width of the pattern element of the ruled line adjustment pattern.

The clock unit 7 of the present embodiment has an ASIC (Ap
Application Specific IC) and mainly detects T1 when detecting a ruled line adjustment pattern.
The intermediate point T2 between T1 and T3 is treated as the detection timing of the ruled line adjustment pattern. However, it is also possible to detect the width of the pattern element by setting the detection timing of the pattern element to T1 and T3 by setting the clock section 157 of the CPU 151.

When the CPU 151 sends an instruction to the clock unit 157 to count, the clock unit 157 looks at the output signal of the photosensor 156 based on the instruction and counts the clock from the intermediate point T2 of a certain pattern element. Start,
The counting ends at the midpoint of the next pattern element. The count result, that is, the interval between the pattern elements is detected with a resolution smaller than one dot. The same applies to the width of the pattern element. The count result is sent to the CPU 151. The CPU 151 performs correction, which will be described later, based on the transmitted count number and the scan speed of the carriage.

FIG. 10 shows a change in satellite (particularly a change in size) depending on the printing speed. The size of the satellite generated at the time of pattern printing increases as the speed of the carriage for printing increases (c). When the speed is low, the value becomes smaller (b), and when the speed is further reduced, the value decreases to a level that can be neglected to some extent during sensor detection (a).

Based on this, the ruled line adjustment pattern (FIG. 3) is printed at two speeds, the carriage speed used in actual bidirectional printing and a sufficiently low speed which is not affected by satellites. Measure the width.

FIGS. 11 (a) and 11 (b) show the state of the pattern measurement as viewed from the front of the carriage similarly to FIG. 4. FIG. 11 (a) shows the pattern at a low speed which is not affected by the satellite. FIG. 11B shows a print at the speed used in actual bidirectional printing. The widths of the pattern elements 32 and 31 printed at a low speed are h1 and h2, respectively, and the pattern elements 3 printed at the speed used in actual bidirectional printing are used.
The widths of 2 ′ and 31 ′ are h1 ′ and h2 ′, respectively. 11 (a) and 11 (b), the difference between the sensor reading values caused by satellites during bidirectional printing is as follows.
H2'-h2 (dot) in the forward direction, h1 'in the backward direction
−h1 (dot). Since the distance y '(dot) between the patterns detects the center value of the output print pattern, the effect of the satellite on the sensor read value generated when the ruled line adjustment pattern is printed at the bidirectional printing speed (that is, the satellite). Error value)

{(H1 '+ h2')-(h1 + h2)}
/ 2 (dots). Therefore, the ruled line adjustment value (correction value) actually obtained
Is

X− [y ′ + ｛(h1 ′ + h2 ′) − (h
1 + h2)｝ / 2] (dot). The number of dots of the ruled line adjustment value obtained in this way is not limited to an integer value, but may be a decimal value. Further, in the present embodiment, the ink ejection timing can be set with a resolution of less than one dot in accordance with such a decimal value.

In addition, in consideration of the adjustment pattern to be printed for calculating the error value in FIG. 11 and the reading error of the optical sensor, etc., a plurality of printing patterns are printed as shown in FIG. You may ask.

FIG. 12 is a schematic diagram of a straight line bidirectionally printed using the ruled line adjustment values obtained by the above method.
It can be seen that the main drops of the dots at the boundary between the straight line printed in the forward direction and the straight line printed in the backward direction are aligned on a straight line. This assumes a case where the satellite is detected by the photo sensor, but is less noticeable to human eyes.

As described above, in the present embodiment, ruled line adjustment can be performed by determining a ruled line correction value that matches the main drop of the forward and backward dots at the boundary of a straight band.

Next, a second embodiment of the present invention relates to automatic adjustment of ruled lines when the bidirectional printing speed is faster than in the first embodiment and the satellite is also noticeable (visible) to humans. An example is shown. Also in the second embodiment, the control block diagram of FIG.
Only the control of the PU 151 is performed.

As described above, when the printing speed is increased, the size of the satellite is increased as shown in FIG. 10C. In an extreme case, the satellite may be generated twice. In such a state, if ruled line correction is performed by the method as in the first embodiment, the ruled lines appear to be out of alignment due to the satellite because the main drops are aligned as shown in FIG. Would. In such a case, when adjusting the ruled line, it is more appropriate to adjust the ruled line position in such a direction that the main drop and the satellite are aligned with each other, rather than aligning the main drop in the forward direction and the main drop in the backward direction. The printed ruled lines appear to match the appearance.

As a method of obtaining such an adjustment value, an error value due to an actually measured satellite is used.

{(H1 '+ h2')-(h1 + h2)}
/ 2 (dot) is multiplied by a coefficient α,

X− [y ′ + α × ｛(h1 ′ + h2 ′) −
The ruled line correction value is calculated as (h1 + h2)｝ / 2] (dot).

However, the size of the satellite depends on the printing speed and the like, and the final judgment on whether or not the ruled lines match is left to human recognition. Therefore, the coefficient α is determined in advance by experiment for each printing speed. It is a positive value smaller than the set one.

Note that α × ｛(h1 ′ + h2 ′) − (h1
+ H2) It is also conceivable to calculate the ruled line correction value using｝ / 2 (dot) itself as a complete constant for each printing speed. However, in such a case, since external factors such as environmental temperature are ignored, a ruled line correction value is calculated based on a value obtained by multiplying an error value due to a satellite actually read from the optical sensor by a coefficient α. It is more desirable to do.

FIG. 14 is a schematic diagram of a vertical straight line when bidirectional printing is performed using ruled line correction values obtained by the ruled line correction value calculation method according to the second embodiment.

That is, the printing position is shifted in a direction such that the main drop and the satellite are slightly aligned from the state where the main drops of the dots in the forward direction and the backward direction at the boundary of the straight band are completely matched. By determining the ruled line correction value in this way, the ruled line adjustment is performed in accordance with human recognition (look).

In both the first embodiment and the second embodiment, since the reflectance of light differs depending on the type of paper, optical adjustment is performed before executing automatic ruled line adjustment so that an appropriate amount of light can be obtained. It is necessary to adjust the light amount of the sensor light emitting unit. Regarding this light amount adjustment, a manual type and an automatic type can be considered,
Since it is assumed that the ruled line shift correction method is automatic, it is desirable that the method be automatic. As a method of automatic light amount adjustment, before printing the ruled line adjustment pattern, the light emitting unit is turned on on the recording paper on which the pattern is to be printed, and the light amount of the light emitting unit is adjusted so that the potential of the light receiving unit becomes E1 (V) in FIG. Should be performed.

While the preferred embodiment of the present invention has been described above, various modifications and changes are possible. For example,
In FIG. 3, the widths of the pattern elements of the ruled line adjustment pattern and the intervals between the pattern elements are exemplified. However, the present invention is not limited to these values. , Any size is fine. Also, the plotter has been described as an example, but the present invention can be similarly applied to any inkjet recording apparatus such as a printer and a facsimile machine.

[0053]

According to the present invention, automatic adjustment of ruled lines can be performed without being affected by satellites, and an output image in which ruled lines match can be obtained even in bidirectional printing.

In addition, for a satellite generated during printing, the ruled line can be adjusted in a form most suitable for human recognition (look), and an output image in which the ruled line matches can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a plotter according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the occurrence and correction of ruled line deviation during reciprocating printing in a conventional ink jet recording apparatus.

FIG. 3 is a schematic diagram of a ruled line adjustment pattern (test pattern) for detecting a deviation amount of a ruled line deviation.

FIG. 4 is a diagram for explaining an actual printing state and a corrected printing state of the ruled line adjustment pattern in FIG. 3;

FIG. 5 shows the ruled line adjustment pattern of FIG. 3 continuously printed;
FIG. 9 is a diagram showing a ruled line adjustment pattern in which a reading error of the optical sensor and the like are taken into account.

FIG. 6 is an enlarged view showing a positional relationship between a main drop of a print dot and a satellite.

FIG. 7 is a diagram illustrating a state of a satellite generated when a ruled line adjustment pattern is printed.

FIG. 8 is a schematic diagram showing a state where satellites are not generated and present when a ruled line adjustment pattern is printed.

FIG. 9 is a diagram for explaining erroneous adjustment of a ruled line shift due to generation of a satellite.

FIG. 10 is a diagram for explaining a relationship between a generated satellite size and a printing speed.

FIG. 11 is a diagram for explaining a mechanism of occurrence of erroneous adjustment of a ruled line shift in FIG. 9;

FIG. 12 is a diagram illustrating dot positions and output images after ruled line correction according to the first embodiment.

FIG. 13 is a diagram illustrating a dot position and an output image when main dots are aligned with each other in the second embodiment of the present invention.

FIG. 14 is a diagram illustrating a dot position and an output image after ruled line correction according to the second embodiment of the present invention.

FIG. 15 is a control block diagram of the plotter according to the first embodiment of the present invention.

FIG. 16 is a diagram showing a schematic configuration of the photosensor of FIG.

FIG. 17 is a waveform diagram showing an output signal of the photo sensor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Stepping motor 12 ... Pulley 13 ... Carriage drive belt 14 ... Linear scale 15 ... Carriage 16 ... Linear scale sensor 17 ... Inkjet head 18 ... Optical (photo) ) Sensor unit 19 ・ ・ ・ Platen 21 ・ ・ ・ Ink ejection position 22 ・ ・ ・ Outward output image 23 ・ ・ ・ Return output image 31,32 ・ ・ ・ Pattern element 61 ・ ・ ・ Main drop of output dot 62 ・..Output dot satellite 151... CPU 152... ROM 153... RAM 154... Head control unit 155... Paper transport unit 156.・ Operation unit 161 ・ ・ ・ Photo sensor light emitting unit 162 ・ ・ ・ Photo sensor light receiving unit 163 ・ ・ ・ Recording paper

Claims (5)

[Claims] An ink is ejected from a plurality of nozzles of a print head while a print head is moved along a recording medium to record an image for one band on the recording medium, and the recording medium is conveyed by a predetermined amount. In an ink jet recording apparatus for recording an entire image on a recording medium by repeating an operation of recording an image for the next one band, the print head is separated from the head by a predetermined distance at a designated value along a head moving direction. A test pattern printing means for printing at least two pattern elements by forward printing and backward printing, respectively; and a sensor for detecting the pattern elements while moving along the head moving direction. Pattern detection means for determining the interval and the size of the satellite, and the actual pattern detected by the pattern detection means A ruled line adjustment value calculating means for calculating a ruled line adjustment value for adjusting a ruled line shift between bands in bidirectional printing based on the spacing between elements and the size of the satellite and the indicated value; An ink jet recording apparatus comprising: an ink ejection position correcting unit that corrects an ink ejection position (timing) during bidirectional printing based on a value. 2. A method in which a print head is moved along a recording medium, ink is ejected from a plurality of nozzles of the print head to record an image for one band on the recording medium, and the recording medium is conveyed by a predetermined amount. In an ink jet recording apparatus for recording an entire image on a recording medium by repeating an operation of recording an image for the next one band, the print head is separated from the head by a predetermined distance at a designated value along a head moving direction. A test pattern printing means for printing at least two pattern elements by forward printing and backward printing, respectively; and a sensor for detecting the pattern elements while moving along the head moving direction. A pattern detecting means for obtaining an interval and a width of each pattern element; A ruled line adjustment value calculating means for calculating a ruled line adjustment value for adjusting a ruled line displacement between bands at the time of writing; An ejection position correcting unit, wherein the ruled line adjustment value calculating unit operates the test pattern printing unit at a first speed used for actual printing and at a second speed sufficiently lower than the first speed. A second test pattern is printed, and for the test pattern printed at the first speed,
A difference (hereinafter, referred to as an interval difference) between the detected interval between the two pattern elements and the predetermined interval of the indicated value is obtained, and the width of the pattern element printed at the first speed and the second An ink jet printing apparatus, wherein a difference from the width of a pattern element printed at a speed of 2 (hereinafter referred to as a width difference) is obtained, and a value obtained by correcting the interval difference by the width difference is used as a ruled line adjustment value. . 3. An ink jet recording apparatus according to claim 2, further comprising means for further correcting said calculated width difference according to said first speed. 4. A printing head is moved along a recording medium to discharge ink from a plurality of nozzles of the printing head to record an image of one band on the recording medium, and convey the recording medium by a predetermined amount. In an ink jet recording apparatus for recording an entire image on a recording medium by repeating an operation of recording an image for the next one band, a method for correcting a ruled line displacement between bands in bidirectional printing, the method comprising: A step of printing at least two pattern elements separated by a predetermined distance at a designated value along the head moving direction by a head by forward printing and backward printing, respectively, the pattern elements moving along the head moving direction; Determining the distance between the two pattern elements and the size of the satellite based on the output of the sensor for detecting Calculating a ruled line adjustment value for adjusting a ruled line displacement between bands during bidirectional printing based on the actual pattern element spacing and satellite size detected by the pattern detection means and the designated value. Correcting the ink ejection position (timing) at the time of bidirectional printing based on the calculated ruled line adjustment value. 5. A print head is moved along a recording medium, ink is ejected from a plurality of nozzles of the print head to record an image of one band on the recording medium, and the recording medium is conveyed by a predetermined amount. In an ink jet recording apparatus for recording the entire image on a recording medium by repeating an operation of recording an image for the next one band, a method of correcting a ruled line displacement between bands in bidirectional printing, Printing at least two pattern elements separated by a predetermined distance along a head moving direction at predetermined intervals along a head moving direction by forward printing and backward printing, respectively, at the first speed used for printing; At a second speed which is sufficiently lower than the speed, at least two pattern elements separated by the predetermined distance by the indicated value along the head moving direction are printed in the forward direction, respectively. A step of printing a direction printing, the test pattern image printed by the first speed,
Detecting a detected interval between the two pattern elements and a predetermined interval of the indication value, and calculating a difference between the detected intervals (hereinafter, referred to as an interval difference); and determining a difference between the pattern elements printed at the first speed. Obtaining a difference between the width and the width of the pattern element printed at the second speed (hereinafter, referred to as a width difference); and obtaining a ruled line adjustment value obtained by correcting the interval difference with the width difference. Correcting the ink discharge position (timing) at the time of bidirectional printing based on the obtained ruled line adjustment value.