JP2994690B2 - Image recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus using a multi-head.

[Conventional technology]

With the spread of computers and communication devices, digital image recording using an inkjet or thermal transfer recording head as an image recording apparatus has been rapidly spreading. In an image recording apparatus using a recording head, a multi-head in which a plurality of image recording elements are integrated is generally used in order to improve a recording speed. For example,
In a recording head of the ink jet system, a multi-nozzle head in which a plurality of nozzles are integrated is generally used, and a thermal head of a thermal transfer system generally includes a plurality of heaters.

However, it is difficult to uniformly manufacture a multi-head image recording element, and the characteristics of each image recording element vary to some extent. For example, in the ink jet type multi-head, there is a variation in the shape of the nozzle, and in the thermal transfer type multi-head, there is a variation in the shape, the resistance value, etc. of the heater. The non-uniformity of the characteristics among the image recording elements results in non-uniform dot sizes and densities recorded by the image recording elements, which eventually causes density unevenness in the recorded image. To cope with this problem, various methods have been proposed for obtaining a uniform image by correcting a signal applied to each image recording element. For example, in a multi-head 31 in which the recording elements 30 are arranged as shown in FIG. 2A, when the input signals to the respective image recording elements are made uniform as shown in FIG. When such density unevenness occurs, the input signal is corrected and a large input is applied to the image recording element in the low density part and a small input is applied to the image recording element in the high density part as shown in FIG. . In the case of a recording system capable of modulating the dot diameter or dot density, the dot diameter to be recorded by each image recording element is modulated according to the input.

For example, the driving voltage or pulse width applied to each piezo element is changed in a piezo ink jet, and the driving voltage or pulse width applied to each heater in a thermal transfer method is changed according to an input signal, and the dot diameter or dot by each recording element is changed. The density is made uniform, and the density distribution is made uniform as shown in FIG. When it is impossible or difficult to modulate the dot diameter or the dot density, the number of dots is modulated in accordance with the input signal, so that the image recording element in the low density portion prints many dots in the high density portion. The printing element prints a small number of dots to make the density distribution uniform as shown in FIG. 2 (e).

This correction amount is obtained, for example, as follows. As an example, a case in which density unevenness of a multi-head of 256 nozzles is corrected will be described.

It is assumed that the density unevenness distribution when printing with a certain uniform image signal S is as shown in FIG. First, to determine the concentration OD ₁ ~OD ₂₅₆ in the portion corresponding to each nozzle, the average concentration Ask for. Next, ▲ ▼ / OD _n is calculated.

If such relationship between the value and the image density OD of the image signal S is of FIG. 4, in order to make the density of OD _n by correcting the signal S to the ▲ ▼ is the S Should be corrected. For this purpose, the image signal may be subjected to table conversion as shown in FIG. In FIG. 5, a straight line A is a straight line having a slope of 1.0, and the input is output without any conversion. On the other hand, B has a slope, And the output signal when the input signal S is input is α · S.

Accordingly, if the head is driven after performing a table conversion as shown in FIG. 5B on the image signal corresponding to the n-th nozzle, the density of the portion printed by this nozzle becomes ▲
It becomes equal to ▼. If such processing is performed for all nozzles, density unevenness is corrected, and a uniform image is obtained. That is, unevenness can be corrected by previously obtaining data indicating what kind of table conversion should be performed on an image signal corresponding to which nozzle.

The density unevenness can be corrected by the above-described method. However, in this method, even if the unevenness can be corrected once, if the density unevenness subsequently changes, it is necessary to change the correction amount for the input signal. In the case of an ink jet head, it is often observed that the concentration distribution changes due to deposition of ink from the ink near the ink discharge port or foreign matter from the outside as the ink jet head is used. Further, even in the case of a thermal transfer head, each heater may be deteriorated or deteriorated, and the density distribution may be changed.

In such a case, there is a problem in that the density unevenness correction becomes insufficient with the initially set input correction amount, so that the density unevenness gradually becomes conspicuous with use.

For this reason, as disclosed in Japanese Patent Application No. 1-107744 (Japanese Patent No. 2,854,318), the applicant has provided a density unevenness reading section in the image recording apparatus, and periodically reads out the density unevenness distribution to obtain the density unevenness. A method to recreate the correction data was proposed. According to this method, even if the density unevenness distribution of the head changes, the correction data is re-created in accordance with the change, so that a uniform image without unevenness can always be maintained.

FIG. 6 shows an example of a density unevenness reading head used in such a method, where 1 is a recording paper on which an unevenness measurement pattern is printed,
2 is a lamp, 3 is a photodiode, 4 and 5 are lenses,
Reference numeral 6 denotes a movable density unevenness reading head on which these are mounted. By scanning the density unevenness reading head 6 having such a configuration, the unevenness distribution is read, and unevenness correction data is created again.

The light of the lamp 2 is converted into parallel light by the lens 4 and the recording paper 1
The upper unevenness measurement pattern is irradiated. The reflected light enters the photodiode 3 through the Apachiya 7 of the lens 5 and the aperture d _0. Light incident at this time the photodiode 3 is light of d ₁ of the circumference of the unevenness measurement pattern. Accordingly, the one obtained by averaging the unevenness pattern of the range of d ₁ has been detected. By scanning such a density unevenness reading head 6, unevenness of the unevenness measurement pattern is detected.

From this detection result, the value of ▲ / OD _n is recalculated for 256 nozzles as described above and the unevenness correction data is rewritten, so that a uniform image without unevenness can always be obtained.

In this work, in general, it is actually difficult to obtain an image without any unevenness by one operation, and it is usually necessary to repeat the work several times until an image without unevenness is obtained. In particular, a sufficient unevenness correction effect can be obtained by confirming with the image that the obtained unevenness correction data has sufficiently performed unevenness correction and then ending the work. Next, the configuration of an image recording apparatus that rewrites the above-described unevenness correction data will be described.

First, the image reading section will be described with reference to the schematic perspective view of FIG.

In FIG. 7, reference numeral 60 denotes a document reading head, which reads a document S by sliding on a pair of guide rails 61, 61 '. The document S is placed downward on a transparent glass (not shown) provided on the scanning portion of the document reading head 60. An original reading head 60 is a light source 62 for illuminating the original, and a lens 6 for forming an original image on a photoelectric conversion element group such as a CCD.
It is composed of 3 grades. Reference numeral 64 denotes a flexible bundle of conducting wires for supplying power to the light source 62 and the photoelectric conversion element and transmitting image signals and the like from the photoelectric conversion element.

The document reading head 60 is fixed to a driving force transmitting unit 65 such as a wire for main scanning (B and E directions). The driving force transmitting section 65 in the main scanning direction is stretched between pulleys 66 and 66 ', and is moved by the rotation of a pulse motor 67 for main scanning. Due to the rotation of the pulse motor 67 in the direction of arrow A, the document reading head 60 moves in the direction of arrow B while
The row information of the document S orthogonal to the direction is read by the number of bits corresponding to the photoelectric conversion element group.

After the required width of the document S has been read, the main scanning pulse motor 67 rotates in the direction opposite to the arrow A. As a result, the original reading head 60 moves in the direction E and returns to the initial position. Reference numerals 68, 68 'denote carriages, and guide rails 69, 69' for the sub-scanning (D) direction substantially orthogonal to the main scanning direction B.
Slide up. The carriage 68 'is fixed by a fixing member 70 to a driving force transmission unit 72 for the sub-scanning (D) direction such as a wire stretched over the pulleys 71, 71'.

After the main scanning B is completed, the pulley 71 is driven by a sub-scanning drive source (not shown) such as a pulse motor or a servomotor.
Rotates in the direction of arrow C and moves a predetermined distance (the same distance d as the read image width in the main scanning B direction), and the carriages 68 and 6 move.
8 'is sub-scanned in the direction of arrow D and stopped. Here, the main scanning B is started again. By repeating the main scanning B, the return E in the main scanning direction, and the sub-scanning D, the entire original image area can be read.

The read image signal is sent to an image forming unit after being subjected to color correction processing such as logarithmic conversion, UCR, masking, and color balance adjustment.

 Next, the image forming unit shown in FIG. 8 will be described.

The image forming section employs a drop-on-demand type ink jet recording head.

In FIG. 8, a recording material 40 wound in a roll shape is conveyed in a 44 direction by being sandwiched and rotated by a feeding roller 43 via conveying rollers 41 and 42. Guide rails 46 and 47 are placed in parallel across the recording material 45, and a recording head unit 49 mounted on a carriage 48 scans right and left.

The carriage 48 has four color heads 49Y, 49M, 49C, and 49Bk of yellow, magenta, cyan, and black, on which four color ink tanks are arranged. Each head is a multi-nozzle head with 256 nozzles.
The recording material 45 is intermittently fed by the print width of the recording head 49. When the recording material 45 is stopped, the recording head 49 scans in the P direction and ejects ink droplets according to the image signal.

As described above, the color image is formed by performing the color correction processing after reading the document and then performing the ink discharge according to the image signal.

Further, a density unevenness reading head 50 is arranged to face the recording surface of the recording material 45. The configuration of the density unevenness reading head 50 is the same as that shown in FIG. Record head 49
After the test pattern is printed, the recording material 45 is fed in the direction 44 by the feed roller 43, and the test pattern passes under the density unevenness reading head 50. During this passage, the density unevenness reading head 50 reads the density unevenness.

The recording head 49 is a so-called bubble jet type recording head which causes a state change such as film boiling in the ink by thermal energy, and discharges the ink from a discharge port toward a recording material using generated bubbles. In this recording head 49, the size of the heating resistor (heater) provided in each ejection port is much smaller than that of a piezoelectric element used in a conventional ink jet recording apparatus. It is possible to obtain a high-quality recorded image, and has features such as high speed and low noise.

Next, an image data processing section for correcting the density unevenness of each recording head of the image forming section will be described with reference to the block diagram of FIG.

For the sake of simplicity, in the following description, processing for one head will be described. To get a full-color image,
Similar processing may be performed on the color head.

In FIG. 9, reference numeral 101 denotes image data read by the image reading unit in FIG. 7, reference numeral 102 denotes an image processing unit which performs processes such as logarithmic conversion, masking, UCR, and color balance adjustment, and reference numeral 103 denotes an image signal after image processing. Reference numeral 104 denotes a ROM in which the unevenness correction table is stored. 105 is an image signal after unevenness correction, 106 is 2
A digitizing circuit, 107 is a binarized image signal, 108 is a head driving circuit, 109 is a head driving signal, 110 is a multi-nozzle recording head, and is one of 49Y, 49M, 49C, and 49Bk in FIG. Equivalent to one. Reference numeral 111 denotes a density unevenness reading head, which corresponds to 50 in FIG. 112 is uneven reading signal, 113 is RAM, 1
15 is a CPU, 116 and 118 are unevenness correction signals, 117 is unevenness correction RAM
It is.

The image-processed signal 103 is output to the unevenness correction table ROM 104
Is converted so as to correct the unevenness of the recording head. As shown in FIG. 10, the unevenness correction table ROM 104 has 61 correction straight lines in which the inclination from Y = 0.70X to Y = 1.30X is different by 0.01 when the input image signal is X and the output image signal is Y, The correction straight line is switched according to the unevenness correction signal 118. For example, when a signal of a pixel to be printed by a nozzle having a large dot diameter is inputted, a correction straight line having a small inclination is selected, and when a nozzle having a small dot diameter is selected, a correction straight line having a large inclination is selected to correct the image signal.

The non-uniformity correction RAM 117 stores a correction straight line selection signal necessary for correcting non-uniformity of each nozzle. That is, a non-uniformity correction signal having 61 types of values from 0 to 60 is stored for 256 nozzles, and a non-uniformity correction signal 118 is output in synchronization with an input image signal.

The corrected image signal 105 corrected by the selected straight line is
A binarization circuit 106 using a dither method, an error diffusion method, etc.
After being converted into a value, it is input to the head drive circuit 108. The head drive circuit 108 outputs a drive pulse suitable for the head according to the binary signal, and performs image recording using the recording head 110.

By performing such processing, the print duty is reduced by the nozzles in the portion where the recording head density is high, and the print duty is raised by the nozzle in the thin portion. As a result, the density unevenness of the recording head is corrected, and a uniform image is obtained.

However, when the density unevenness pattern of the recording head changes with use, the unevenness correction signal becomes inappropriate,
Density unevenness occurs on the image. In such a case, the unevenness correction data is rewritten in the unevenness correction signal rewriting mode.

In the unevenness correction data rewriting mode, the following operation is performed.

First, an unevenness correction table is generated by a control signal (not shown).
All the ROMs 104 are straight lines with a slope of 1.0, and no unevenness correction is performed. Subsequently, a test pattern for non-uniformity correction is output from a signal source (not shown) and is recorded by the recording head 110 for three lines. Here, a uniform halftone of 50% duty is used as the test pattern.

FIG. 11 shows the test pattern for correction.
1 is a recording paper, and 200 is a recording pattern for three rows.

The test pattern recorded by the recording head 110 passes under the density unevenness reading head 111.
The density unevenness reading head 111 reads the density unevenness.

At the time of reading, two edges of the signal are detected when the recording paper changes from a white background to the recording pattern 200 and conversely, when the recording pattern changes to the white background again. This 2
Of the read signal sandwiched between
The signals for the pixels are sampled, and these are read data corresponding to each nozzle.

Assuming that these data are R ₁ , R ₂ ... R ₂₅₆ , R _{1 to} R ₂₅₆ are temporarily stored in the RAM 13 and then subjected to the following arithmetic processing by the CPU 115.

These data are Subjected to become operational, it is converted into density signals C _n.

Next, average density Ask for.

Subsequently, how much the density corresponding to each nozzle deviates from the average density is calculated as follows.

ΔC _n = C / C _n Next, a signal correction amount ΔS _n according to ΔC _n is obtained by ΔS _n = K × ΔC _n . Here, K is a coefficient determined by the gradation characteristics of the head. For example, if the gradation characteristic is linear, K
= 1, but otherwise, if the value of K is set in the range of about 0.6 to 1.4, the number of work repetitions can be reduced. Subsequently, a selection signal of a correction straight line to be selected according to ΔS _n is obtained, and a non-uniformity correction signal having 61 values of
The unevenness correction RAM 117 for six nozzles is stored.

For example, when ΔS _n = 1.1 Since the density of this nozzle is 1 / 1.1 of the average density, a non-uniformity correction signal for selecting a correction straight line having an inclination of 1.1 is stored in the RAM 117. That is, the correction data is such that a correction straight line having a slope equal to ΔS _n is selected for each nozzle.

A gamma straight line is selected for each nozzle based on the unevenness correction data created in this way, and the unevenness in density is corrected.

[Problems to be solved by the invention]

In this way, it is possible to rewrite the unevenness correction data at any time, but there are the following problems.

In ink jet recording, when ink is absorbed by paper, it is absorbed while spreading (bleeding) in the horizontal direction. Therefore, when a test pattern as shown in FIG. 11 is printed, the printing width of the first row is a value slightly larger than the width of 256 nozzles. Therefore, by setting the sub-scanning amount of the paper to a value slightly larger than the width of 256 nozzles, the next line of each line is made inconspicuous.

However, the amount of spread of the recording width differs depending on the amount of ink to be printed. When a large amount of ink is printed, the amount of spread is large, and when the amount of ink is small, the amount of spread is small.

On the other hand, the test pattern for creating unevenness correction data is 50
It is not limited to the print duty of%. A print duty of about 80% is desirable for creating unevenness correction data suitable for dark originals, and about 30% for thin originals. This is because the gradation characteristics of the head are not necessarily linear, so that even if correction is performed at a certain density, a slight unevenness may remain at another density. Therefore, it is necessary to change the print duty of the test pattern according to the user's request.

When the sub-scanning amount of the paper is set to be optimal when the printing duty is 50%, printing a test pattern with a duty of 80% increases the spread width. The density at the joint increases.
When creating unevenness correction data with such a pattern,
Data is generated that selects a γ straight line having a small inclination with respect to the end nozzle. When such data is actually copied, there is a problem that the end of each line becomes thin and the next line becomes white streaks.

Conversely, when actual copying is performed using unevenness correction data created with a test pattern having a low printing duty, there is a problem that the next line of each line becomes a black stripe. Further, the same problem as described above occurs depending on the type of the recording material. Accordingly, the present invention has been made to solve the above-described problem, and it is possible to obtain a uniform image in which the next image is not noticeable even if the printing duty of the test image or the recording material changes. It is intended to provide a device.

[Means for solving the problem]

An image recording apparatus according to claim 1 of the present invention uses a recording head in which a plurality of image recording elements for discharging ink are arranged, and discharges ink onto a recording material to record an image. A main scanning unit that relatively scans the recording head and the recording material along a main scanning direction different from the arrangement direction of the image recording elements; and A sub-scanning unit that relatively scans in a sub-scanning direction different from the scanning direction, and repeating the scanning by the main scanning unit and the scanning by the sub-scanning unit, and recording by the recording head during the scanning in the main scanning direction. Test pattern recording means for recording a test pattern in which a predetermined pattern to be performed is made adjacent in the sub-scanning direction,
Correction data for making the density distribution of the plurality of image recording elements of the recording head uniform based on the density distribution of a predetermined area of the test pattern, the correction data corresponding to the plurality of image recording elements; And a control unit for changing the amount of sub-scanning by the sub-scanning unit when recording the test pattern in accordance with the type of recording material on which the test pattern is to be recorded. .

According to a second aspect of the present invention, there is provided an image recording apparatus which controls the duty of a test pattern recorded by the test pattern recording means in place of the control means of the first aspect, and Control means for changing the amount of sub-scanning by the sub-scanning means when printing is performed in accordance with the duty of the test pattern.

〔Example〕

Hereinafter, embodiments of the image recording apparatus of the present invention,
This will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.
In FIG. 1, portions having the same functions as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 121 denotes a test pattern generation circuit that generates a test pattern signal 126 having a density level corresponding to a control signal 125 from a CPU 115, and 120 denotes a switch that selectively switches between a normal image signal 105 and a test pattern signal 126. CPU
Switching is performed by a selection signal 124 from 115. Reference numeral 131 denotes a print duty selection unit for selecting the print duty of the test pattern, 132 denotes a print duty selection signal, 134 denotes a sub-scanning pulse motor, and 133 denotes a drive signal for the sub-scanning pulse motor 134.

In the above configuration, in the unevenness correction data rewriting mode,
First, the print duty of the test pattern is selected by the print duty selection means 131. The print duty is set to about 80% when priority is given to correcting unevenness in high density areas, and to about 30% when importance is attached to low density areas. The CPU 115 receives the selection signal 132 from the print duty selection unit 131 and sends a corresponding control signal 125 to the test pattern generation circuit 121. The test pattern generation circuit 121 generates a print duty test pattern signal 126 according to the control signal. The switch 120 selects the image signal 103 during normal copying, but selects the test pattern signal 126 during non-uniformity correction data rewriting mode.

Further, the CPU 115 drives the sub-scanning pulse motor 134 with the driving signal 133 having the number of pulses corresponding to the print duty selection signal 132, and performs sub-scanning of the test pattern. At this time, when the print duty of the test pattern is high, the sub-scan feed amount is increased to prevent overlapping of the next line due to ink bleeding, and when the print duty is low, the feed amount is reduced. According to experiments, when using a recording head with 400 dpi and 256 nozzles, the print duty is 15-20 μm at 30% and 80%.
Good results were obtained with a slight change in the feed amount.

As described above, by using the test pattern obtained with the sub-scan feed amount corresponding to the print duty, it is possible to create accurate unevenness correction data. An image is obtained.

Next, another embodiment of the present invention will be described. This embodiment corresponds to the fact that the amount of ink bleeding changes when the recording paper changes.

FIG. 12 is a block diagram showing this embodiment, in which parts having the same functions as in FIG. In the drawing, reference numeral 135 denotes a recording paper detection unit, and 136 denotes a recording paper signal.

The recording paper detection unit 135 detects the type of recording paper used. As the detection method, a known method such as an optical detection unit is used, but a method set by a user may be used.

The CPU 115 changes the sub-scan amount at the time of test pattern printing according to the type of recording paper.

For example, since the amount of bleeding is large on OHP paper, the sub-scanning amount is increased as compared with the case of normal recording paper. In the case where an ink absorbing layer is provided on a transparent substrate to absorb ink and an image is observed from the transparent substrate side, the sub-scanning amount is increased for the same reason.

By doing so, it is possible to create unevenness correction data from which a good image with no streaks can be obtained even if the recording material changes.

Next, still another embodiment of the present invention will be described. In this embodiment, the sub-scanning amount is changed in consideration of both the print duty of the test pattern and the type of the recording material.

FIG. 13 is a block diagram showing this embodiment. Parts having the same functions as in FIG. In the figure, the CPU 115 stores the relationship between the print duty and the optimal sub-scan amount for each type of recording material, and performs sub-scanning with the optimal number of sub-scan pulses in consideration of both the recording material and the print duty. The pulse motor 134 is driven.

In this embodiment, since the sub-scanning amount is determined in consideration of both the print duty of the test pattern and the type of the recording material, it is possible to create unevenness correction data with higher accuracy than the previous embodiment. it can.

The present invention is not limited to the ink jet recording system, but is also applicable to a fusion type or sublimation type thermal transfer recording system. The present invention can be similarly applied to a multi-head recording method having a plurality of recording elements.

In the above-described embodiment, the number of dots is corrected as a method for correcting density unevenness. However, the dot diameter may be corrected by modulating the voltage or pulse width of a head drive pulse.

In the above-described embodiment, an image recording apparatus having an image reading unit and an image forming unit has been described. However, a printer that does not have an image reading unit and that inputs an image signal from a computer or the like and outputs an image may be used. The present invention can be similarly implemented.

Further, in the above-described embodiment, a dedicated density unevenness reading head is provided for reading a test pattern, but may be used also as a reading head for reading a document.

〔The invention's effect〕

As described above, according to the present invention, in printing a test pattern for creating data for correcting density unevenness of a print image caused by variation in characteristics of each print element of a print head, the duty of the test pattern By recording a test pattern in which the occurrence of the next streak is suppressed even when the type of the recording material or the like changes, correction data corresponding to each image recording element can be appropriately created, and density unevenness can be reduced. A good recorded image can be obtained by reduction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an image recording apparatus according to the present invention, FIGS. 2 to 5 are explanatory diagrams for explaining density unevenness correction, and FIG. 6 is a detail of a density unevenness reading head. 7 and 8 are schematic perspective views showing an image reading section and an image forming section, respectively. FIG. 9 is a block diagram showing a conventional image recording apparatus, and FIG. 10 explains a non-uniformity correction table ROM. 11 to 13 are block diagrams showing another embodiment of the present invention. 104: Unevenness correction table ROM 110: Recording head 111: Density unevenness reading head 117: Unevenness correction RAM 121: Test pattern generation circuit 131: Print duty selection unit 134: Sub-scanning pulse motor 135: Recording Paper detector

Claims (4)

(57) [Claims] An image recording apparatus for recording an image by ejecting ink onto a recording material using a recording head having a plurality of image recording elements for ejecting ink, wherein the recording head and the recording material are Main scanning means for relatively scanning along a main scanning direction different from the arrangement direction of the image recording elements, and the recording head and the recording material are relatively moved in a sub-scanning direction different from the main scanning direction. Sub-scanning means for scanning, and repeating the scanning by the main scanning means and the scanning by the sub-scanning means, a predetermined pattern to be recorded by the recording head during the scanning in the main scanning direction in the sub-scanning direction Test pattern recording means for recording test patterns adjacent to each other along the density, density based on density distribution of a predetermined region of the test pattern, and Correction data creating means for creating correction data for making the distribution uniform, corresponding to the plurality of image recording elements; and an amount of sub-scanning performed by the sub-scanning means when the test pattern is recorded. An image recording apparatus, comprising: control means for changing a pattern according to a type of a recording material on which the pattern is recorded. 2. An image recording apparatus for recording an image by discharging ink onto a recording material using a recording head having a plurality of image recording elements for discharging ink, wherein the recording head and the recording material are Main scanning means for relatively scanning along a main scanning direction different from the arrangement direction of the image recording elements, and the recording head and the recording material are relatively moved in a sub-scanning direction different from the main scanning direction. Sub-scanning means for scanning, and repeating the scanning by the main scanning means and the scanning by the sub-scanning means, a predetermined pattern to be recorded by the recording head during the scanning in the main scanning direction in the sub-scanning direction Test pattern recording means for recording test patterns adjacent to each other along the density, density based on density distribution of a predetermined region of the test pattern, and Correction data creating means for creating correction data for making the distribution uniform, corresponding to the plurality of image recording elements, and controlling the duty of a test pattern recorded by the test pattern recording means, An image recording apparatus, comprising: control means for changing the amount of sub-scanning performed by the sub-scanning means when printing is performed in accordance with the duty of the test pattern. 3. The correction data creating means determines an end of the test pattern on the basis of a predetermined level of density based on a result of reading the density of the test pattern, and determines the determined test pattern. Generating the correction data by determining an area recorded in a specific main scan based on both ends of the recording head and specifying the density of the determined area and the positions of a plurality of image recording elements of the recording head. The image recording apparatus according to claim 1, wherein: 4. The image recording device according to claim 1, wherein said image recording element is a thermal energy generating means for generating thermal energy, and causes a state change of the ink due to heat, and discharges the ink based on the state change. 3. The image recording apparatus according to any one of 3.