JP2006192642A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus capable of simultaneously performing a plurality of adjustments by one printing by using one printing mode without changing the printing mode during printing, and capable of making the amount of carrying of recording media necessary for finishing the adjustment to be only the amount of carrying of the recording media of the adjustment pattern most necessary for the amount of carrying of the recording media among the patterns for adjustment arranged in the printing chart for the adjustment. <P>SOLUTION: In the inkjet recording apparatus, by using a recording head equipped with a plurality of groups of nozzles consisting of a plurality of the nozzles, the recording head is scanned for a plurality of times on the recording media during carrying the recording media to correspond to different groups of the nozzles on the same scanning region on the recording media, and an image is formed by forming dots with the ink delivered from the nozzles. In a method for the adjustment characterized by that the image formed by the scanning at a first time and the image formed by a scanning after the first time complement with each other, a plurality of adjustment patterns are arranged to a sheet of the printing chart for the adjustment to correspond to respective adjustment patterns with a sheet of the printing mask. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inkjet image recording apparatus that forms an image on a recording medium by ejecting ink.

2. Description of the Related Art As an output device such as a computer or a workstation, an ink jet image recording apparatus that forms an image on a recording medium by ejecting ink is known. This ink jet image recording apparatus includes a recording head in which nozzles for discharging normal ink are formed, a carriage on which the recording head is mounted and reciprocatingly scanned in a predetermined direction, and a recording medium in a direction perpendicular to the predetermined direction. And a recording medium transport device.

When an image is formed on the recording medium, the recording medium being conveyed by the recording medium conveying device is temporarily stopped, and the nozzle outlet (ink discharge) of the recording medium is scanned while reciprocating the carriage in the predetermined direction. An image for one band is formed in a portion located in the image forming area facing the exit. Thereafter, the recording medium is transported by a width corresponding to one band, stopped, ink is ejected from the nozzles based on the image signal while the carriage is reciprocated in the predetermined direction, and the image forming area of the recording medium is discharged. An image is formed at a newly located portion. By repeating such an operation, an image is formed on the recording medium.

In an image recording apparatus that ejects ink, such as the ink jet type image recording apparatus, after recording for the nozzle width, the operation of conveying the recording medium for the nozzle width and recording for the nozzle width again is repeated. Therefore, there is a problem that when the paper conveyance amount for the nozzle width is large, a gap is generated in the dot at the joint of the band, and when it is small, the dot overlaps. Also, during multi-pass printing, dot misalignment occurs with respect to the target pixel, resulting in image unevenness.

Further, in an image recording apparatus that ejects ink, such as the above-described ink jet type image recording apparatus, a dot is formed due to variations in the position and orientation of nozzles formed in a recording head provided, and variations in the amount of ink discharged. However, image deviation such as density change and color change occurs.

Further, in an image recording apparatus that ejects ink, such as the ink jet type image recording apparatus, a carriage that is mounted with a recording head and reciprocally scans in a predetermined direction may tilt, and the nozzle rows formed in the recording head Is inclined in a certain direction with respect to the ideal state, and during printing, the dots are displaced from the pixel of interest, resulting in image unevenness.

However, the characteristics of the recording head have a predetermined tolerance. In addition, the recording medium conveying apparatus has a predetermined tolerance. For this reason, conventionally, adjustment is performed by printing an adjustment pattern corresponding to each of a plurality of types of adjustment items, and setting a correction value based on information obtained from the printing result. Recently, the resolution of an ink jet recording apparatus has become finer, and the adjustment can be made finer.

Conventionally, when printing an adjustment pattern corresponding to each of a plurality of types of adjustment items, it has been necessary to set a print mode corresponding to each of the adjustment items. After printing an adjustment pattern corresponding to one adjustment item, there is a problem that the print mode must be switched to print an adjustment pattern corresponding to another adjustment item.

In order to solve the above problems, the present invention uses a recording head including a plurality of nozzle groups each including a plurality of nozzles, and the recording head scans the recording medium a plurality of times when the recording medium is transported. An inkjet recording apparatus that forms an image by forming dots with ink ejected from a nozzle corresponding to different nozzle groups in the same scanning region, and an image formed by the first scan and after the first scan In the adjustment method characterized in that the images formed by scanning of each other complement each other, a plurality of types of adjustment patterns are arranged on one adjustment print chart, and each adjustment pattern is supported by one print mask. It is characterized by.

The adjustment method is characterized in that a plurality of types of adjustment patterns are arranged in the scanning direction of the recording head on a single adjustment print chart, and a single print mask corresponds to each adjustment pattern.

As described above, a plurality of types of adjustment patterns are arranged in the scanning direction of the recording head on a single adjustment print chart, and the print mode can be changed during printing by corresponding to each adjustment pattern with a single print mask. It is possible to perform multiple types of adjustments at the same time with one printing mode without changing it, and the conveyance amount of the recording medium required to complete the adjustment can be adjusted using the adjustment printing chart. Only the conveyance amount of the recording medium having the adjustment pattern that requires the most conveyance amount of the recording medium in the pattern can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that the order of colors shown in the embodiments is merely an example and does not limit the present invention.

With reference to FIG. 1, a plotter as an example of the ink jet image recording apparatus of the present invention will be described.

FIG. 1 is a perspective view showing a schematic configuration of a plotter.
The plotter 10 includes a platen 14 on which a recording medium 12 conveyed in the direction of arrow A is placed. Two scanning rails (guide rails) 16 are spanned above the platen 14 in parallel to the platen 14. A carriage 20 that reciprocates in the directions of arrows B and C (directions orthogonal to the direction of arrow A) by a motor (not shown) and a belt 18 is attached to the scanning rail 16 via a slide bearing (not shown). Yes.

The carriage 20 is equipped with four recording heads 22K (black), 22C (cyan), 22M (magenta), and 22Y (yellow) having ink discharge ports (nozzle outlets, not shown) for discharging ink. Has been. In front of the ink ejection opening is an image forming area 23 where an image is formed. Ink is ejected from the ink ejection port to a portion of the recording medium 12 located in the image forming area 23, whereby an image is formed in this portion.

In a corner of the movable range of the carriage 20 away from the image forming area 23, ink is forcibly sucked from the nozzles, and the ink supply path and nozzles formed on the recording head 22 are cleaned and recorded. A recovery device 30 is provided that changes the ink discharge state of the head 22 to the initial discharge state.

In forming an image on the recording medium 12 such as roll paper, the recording medium 12 is placed on the platen 14 and a part of the outer peripheral surface is exposed from an opening (not shown) formed in the platen 14. The recording medium 12 is conveyed by rotating the conveying roller 24 by a motor (not shown) while the recording medium 12 is sandwiched between the conveying roller 24 and the pinch roller 26 that presses both ends of the recording paper 12 from above. The carriage 20 is reciprocated in the directions of arrows B and C above the recording medium 12 to generate image signals carrying image information transmitted from the head control unit (not shown) to the recording heads 22K, 22C, 22M, and 22Y. Based on this, ink is ejected from the nozzles, and an image is formed on the portion of the recording medium 12 located in the image forming area 23. During the image forming operation, when it becomes necessary to suck ink from the nozzles in order to clean the nozzles, the carriage 20 is moved above the recovery device 30. When the image formation is completed, a cutter (not shown) mounted on the carriage 20 is ejected to a predetermined position, and the recording medium 12 is cut into a predetermined size.

The recovery device 30 includes four rubber caps 32K, 32C, 32M, and 32Y that detachably cover the outlets of the nozzles of the four recording heads 22K, 22C, 22M, and 22Y. One end of a tube (not shown) is connected to each cap 32K, 32C, 32M, 32Y, and the other end of the tube is connected to a suction pump (not shown). The four caps 32K, 32C, 32M, and 32Y are fixed to the cap base 32.

FIG. 17 illustrates the outline of the configuration of the control system of the ink jet recording apparatus.
When the CPU 106 receives print information from the host apparatus 101, the CPU 106 performs control of each part of the recording apparatus, data processing, and the like. The ROM 103 stores a processing program relating to each processing procedure, and the RAM 105 is used for executing the processing procedure. Based on the control program stored in the CPU 106 and the ROM 103, the recording information received from the host apparatus 101 is processed using a peripheral unit such as the RAM 105, and processing such as conversion into recording data is executed. The CPU 106 also outputs print data and drive control signals to the recording head control circuit 107. The recording head control circuit 107 drives the recording head 108 based on the input drive data.

  The CPU 106 controls a carriage motor 111 for reciprocating the carriage 20 and a transport motor 112 for transporting a recording medium by a motor driving unit 110.

An outline of multi-pass printing will be described with reference to the multi-pass schematic diagram of FIGS.
FIG. 2 is a print completion drawing, and 33 shows print dots.

FIG. 3 shows a printing procedure for printing FIG. 2 and an example of 4-pass printing. In this figure, A indicates the paper feed direction, B and C indicate the reciprocating scanning direction of the recording head 22, and D indicates the paper feed amount at one time. Circles 1 to 4 correspond to print dots printed on the recording paper using the nozzle circles 1 ′ to 4 ′ of the recording head 22. First, as shown in (a), paper is fed by D, and the printing dot circle 1 is driven using the nozzle circle 1 '. Next, after the paper is again fed by D as shown in (b), the print dot circles 1 and 2 are driven using the nozzle circles 1 'and 2'. Similarly, the paper feed D is repeated as shown in (c) to (f), and the print dot circle 1 is obtained by using the nozzle circles 1 'to 4' by one carriage scan for this one paper feed. ~ I will type in round 4 sequentially. Then, printing is completed in (g), and the image of FIG. 2 is formed.

In this example, four-pass printing is used. In multi-pass printing, an image is formed by n times of feeding, and an image is formed by carriage operation several times for one line without performing n-pass printing or paper feeding. There is multi-pass printing.

The paper feed amount adjusting method of the ink jet recording apparatus according to the present invention will be described with reference to FIGS. 4, 5, 6, 7, 8, 9, and 10.

FIG. 4 shows a proper print image, and FIG. 5 shows a state in which the paper feed amount is shifted. In both figures, 34 is the first pass image and 35 is the second pass image. Circles 1 and 2 are printed dot circles 1 and 2 that are printed using the nozzle circles 1 'and 2' shown in FIG. 3, respectively. Corresponds to 2. X0 and X1 indicate the shift amounts in the paper feed direction of the first pass image 34 and the second pass image 35, respectively. In FIG. 4 where the paper feed amount is appropriate, X0 = 0. However, when the paper feed amount is shifted, a shift amount is generated in the paper feed direction by X1 as shown in FIG.

Normally, as shown in FIG. 5, when the paper feed amount is not appropriate, a completed image is a dirty image due to black streaks or white streaks between lines. However, since the output resolution of the current ink jet recording apparatus is very fine, it is very difficult to determine an appropriate value even if the deviation is compared between the first pass and the second pass. Furthermore, it is difficult to confirm the paper feed state in a state where n-pass overprinting is performed in normal n-pass printing.

Therefore, when the shift amount X3 in the paper feed direction is seen in the first pass image 34 and the fourth pass image 36 as shown in FIG. 6, the shift amount is enlarged. Circles 1 and 4 correspond to the printing dot circles 1 and 4 that are driven using the nozzle circles 1 'and 4' shown in FIG. 3, respectively. At this time, when the amount of deviation X1 in FIG. 5 is compared with the amount of deviation X3 in FIG. 6, it is enlarged three times, and X3 = X1 × 3.

Although FIGS. 4 to 6 show the deviation of the paper feed amount by the print dots, the deviation of the paper feed amount can be expressed by a surface by using the paper feed amount confirmation print mask 37 of FIG. Here, the print mode is assumed to be 8-pass printing. In this print mask 37, a comparison area 38, a reference area 39, and a character print area 40 are provided. In this description, the comparison area 38 is divided into eight for simplification. However, the number of divisions is not limited to this, and an appropriate number for confirming the paper feed amount is desirable. Normally, the deviation of the paper feed amount is confirmed by the images of the comparison area 38 and the reference area 39, and the character print area 40 is used for outputting a correction value, which will be described later. When the print mask 37 is used to print the pattern 41 for confirming the deviation of the paper feed amount, the reference area 39, the character print area 40, and a part of the comparison area 38 are printed in the first pass as in the print procedure 42. Then, printing is not performed in the second to seventh passes, and printing is performed so as to complement the portion not printed in the first pass in the comparison area 38 in the eighth pass, and the paper feed amount confirmation pattern 41 is completed.

In FIG. 8, when the paper feed amount confirmation pattern 41 is printed using the print mask 37, if the paper feed amount is an appropriate value, the comparison area 38 becomes a uniform pattern (solid) as indicated by 43. When the paper feed amount is shifted, a uniform pattern is not formed in the comparison area 38 as shown in 44, and white stripes appear. When the print mode is 8-pass printing, and the paper feed amount deviation amount is X1, the paper feed amount deviation amount in the comparison area 38 formed by the first pass image 45 and the eighth pass image 46 is X7 = X1. Since it is enlarged to x7, it can be easily confirmed that a uniform pattern is not formed in the comparison region 38 and white stripes appear.

An appropriate correction value can be easily determined by printing the paper feed amount check pattern 41 several times by arbitrarily changing the paper feed amount correction value of the main body for adjusting the paper feed amount using the print mask 37. . For correction value +1, the paper feed amount is added by Y1. FIG. 9 shows a case where the correction value is changed between +2 and −2. Reference numeral 47 denotes a correction value switching position. Reference numeral 48 denotes a portion where the correction value is 0, and the pattern 41 is uniform, indicating that the paper feed amount is already an appropriate value without adding the correction value. In this case, the current state may be left as it is. On the other hand, 49 is a portion where the correction value is +1, and the pattern 41 is uniform. At present, the paper feed amount is shifted by Y1 when no correction is applied. In this case, the correction value of the main body is set to +1. That is, if the main body side is set so as to add the paper feed amount by Y1, the paper feed amount can always be an appropriate value in the subsequent printing. In this way, by continuously printing the confirmation pattern while switching the correction value, it is possible to easily determine the appropriate value of the paper feed amount.

Also, when the amount of misalignment is confirmed by 8-pass feeding and an appropriate correction value is found, when the actual printing mode is 4-pass printing, the value measured in 8-pass is doubled, and in 16 passes When printing, a half value can be obtained by calculation, and an optimum paper feed amount correction can be made in any printing pass.
Also, with this adjustment method, the number of paper feeds between the first printing and the last printing is not limited to eight passes, and can be changed depending on the correction accuracy of the main body. Further, the maximum number of times does not need to be the upper limit of the number of main body printing passes.

Such confirmation printing can be easily confirmed by visual observation, but a sensor capable of measuring density can be attached to a carriage or the like to scan the printing area and automatically determine the optimum value by density comparison.

In addition, in the adjustment method of the present invention, when adjustment is performed by complementing the first print image and the last print image, printing in the middle of the carriage operation is unnecessary, so only paper feeding is performed and the carriage operation is omitted. By doing so, the printing time can be shortened.

Next, a method for adjusting the print head inclination (hereinafter referred to as slant) of the ink jet recording apparatus according to the present invention will be described with reference to FIGS.

FIG. 10 shows a proper print image, and FIG. 11 shows a state where the slant is displaced. In this figure, A indicates the paper feed direction, and B and C indicate the reciprocating scanning direction of the recording head 22. 10 and 11 are images in which one dot line is printed by one-pass printing, 51 is a first-pass image, and 52 is a second-pass image. By checking the joint between the images of the first pass and the second pass at the portion E in the figure, it can be determined whether the slant is appropriate or not. If the slant is not appropriate as shown in FIG. 11, the dots will be displaced from the target pixel during printing, resulting in image unevenness.

FIG. 12 is a slant confirmation print image. In the joint between the first pass image and the second pass image in E in the figure, the recording head 22 is moved to the proper position 53 by checking which direction the second pass image is inclined with respect to the first pass image. On the other hand, it is possible to determine which is inclined. More precisely, by measuring the length a of the 1-dot line in the figure and the shift amount b of the joint between the images of the first pass and the second pass, how much the recording head 22 is tilted with respect to the proper position. The amount of inclination α can be obtained.

FIG. 13 shows an example of a slant adjustment method. The carriage 20 on which the recording head 22 is mounted is fixedly supported on the translator 54 by a rotating shaft, and the other is supported by a spring 55. The length of the spring 55 can be adjusted by rotating the eccentric roller 56 and changing the position where the carriage 20 abuts. When the eccentric roller 56 abuts the carriage 20 at the position (1), the length of the spring 55 is the longest. Conversely, when the eccentric roller 56 abuts the carriage 20 at the position (5), The length of the spring 55 is the shortest. An appropriate slant position can be determined by operating the eccentric roller 56 and adjusting the length of the spring 55 from the slant inclination direction or the inclination amount α obtained from the slant confirmation print image of FIG.

Normally, the paper feed amount adjustment method described above must be performed in a different printing mode, that is, eight-pass printing and the slant adjustment method is different from one-pass printing. However, as shown in FIG. 14, in the paper feed amount confirmation print mask 37 of FIG. 7, a print mask in which a part of the character print region 40 that does not directly affect the paper feed amount confirmation is assigned to the slant confirmation region 56. By using 57, two kinds of adjustments, paper feed amount adjustment and slant adjustment, can be performed at the same time without changing the print mode during confirmation printing.

When the paper feed amount adjustment and slant adjustment are performed in two printing modes of 8-pass printing and 1-pass printing, the paper feed amount confirmation pattern 41 is first printed by changing the correction value as shown in FIG. When the paper feed amount confirmation printing 59 is completed, the slant confirmation printing 60 must be performed by switching the printing mode from the 8-pass printing to the 1-pass printing at the printing mode switching position 58. However, the slant confirmation area 56 of the print mask 57 shown in FIG. 14 makes it possible to form one dot line for slant confirmation in one pass even with 8-pass printing, so printing is performed at the print mode switching position 58. Slant adjustment can be performed with 8-pass printing without switching modes. Since there is only one type of printing mode used for printing once, there is no need for a switching time required for changing the printing mode, and the printing time can be shortened.

In the second embodiment, the configuration of the main body is the same as that of the first embodiment. The same applies to the paper feed amount adjustment method, the slant adjustment method, and the confirmation print mask 57 to be used.
Normally, the paper feed amount adjustment method and the slant adjustment method cannot be performed on the same scan, so the two types of images, the paper feed amount confirmation print 59 and the slant confirmation print 60, must be arranged side by side in the paper feed direction. The total printing length for confirmation printing becomes longer. However, as shown in FIG. 16, two types of images, a paper feed amount confirmation print 59 and a slant confirmation print 60, are arranged side by side in the scanning direction of the print head on a single adjustment print chart. The total printing length can be shortened, the amount of paper required for confirmation printing can be saved, and the printing time can be shortened at the same time.

Further, the present invention is not limited to the two types of adjustments of paper feed amount adjustment and slant adjustment, and by preparing corresponding print masks, the type of adjustment and the number of adjustments can be freely set.

The present invention relates to an ink jet image recording apparatus that forms an image on a recording medium by ejecting ink from nozzles formed on a print head.

The perspective view of the inkjet plotter which concerns on this invention Schematic diagram of completed printing in multi-pass printing Example of printing procedure for printing Fig. 2 in 4-pass printing Paper feed amount appropriate printing image The paper feed amount is misaligned The paper feed amount deviation is enlarged Paper feed amount confirmation print mask, paper feed amount confirmation pattern and printing procedure When the paper feed amount confirmation pattern is printed using the paper feed amount confirmation print mask, the normal print image and the paper feed amount are misaligned. Paper feed amount appropriate correction value confirmation printing Slant proper print image Slant is misaligned Slant confirmation printing Slant adjustment method Paper feed amount and slant check printing mask Paper feed amount and slant confirmation printing (arranged in the paper feed direction) Paper feed amount and slant confirmation printing (arranged in the head scanning direction) Configuration diagram of control system of inkjet recording apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plotter 12 Recording medium 14 Platen 16 Scanning rail 18 Belt 20 Carriage 22 Recording head 23 Image formation area 24 Conveyance roller 26 Pinch roller 30 Recovery device 32 Cap 33 Print dot 34 First pass image 35 Second pass image 36 Fourth pass image 37 Paper feed amount confirmation print mask 38 Comparison area 39 Reference area 40 Character print area 41 Paper feed amount confirmation pattern 42 41 printing procedure using 37 43 Paper feed amount appropriate image 44 Paper feed amount misaligned image 45 1 pass Eye image 46 8th pass image 47 Correction value switching position 48 Paper feed amount confirmation print image 49 when correction value 0 is an appropriate value 49 Paper feed amount confirmation print image 50 when correction value +1 is an appropriate value Confirmation print end position 51 First pass image 52 Second pass image 53 Proper slant position 54 Translator 55 Spring 5 Eccentric roller 57 the sheet feeding amount and slant confirmation printing mask 58 slant confirmation area 59 paper feed amount verify print 60 slant confirmation printing

Claims (2)

Using a recording head having a plurality of nozzle groups each consisting of a plurality of nozzles, the recording head scans the recording medium a plurality of times during conveyance of the recording medium, and associates different nozzle groups with the same scanning area on the recording medium. An inkjet recording apparatus that forms an image by forming dots with ink ejected from the nozzle,
In the adjustment method characterized in that the image formed by the first scan and the image formed by the scan after the first scan complement each other, a plurality of types of adjustment patterns are arranged on one adjustment print chart. An ink jet recording apparatus that corresponds to each adjustment pattern with a single printing mask. 2. The adjustment method according to claim 1, wherein a plurality of types of adjustment patterns are arranged in a scanning direction of the recording head on a single adjustment print chart, and a single print mask corresponds to each adjustment pattern. Inkjet recording apparatus.

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