JP4756842B2 - Print position adjusting method and printing apparatus - Google Patents

Description

  The present invention relates to a print position adjusting method and a printing apparatus for adjusting a print position during a printing operation involving a movement of a print head.

  In an inkjet printing apparatus, a configuration is generally known in which a color image can be recorded by ejecting a plurality of colors of ink from ejection openings corresponding to a plurality of colors. In addition, in order to increase the recording speed, a configuration that enables so-called bidirectional recording in which recording is performed during reciprocating scanning of a recording head is also known.

  At the time of ink jet recording in which a color image is recorded as described above, the image quality deteriorates due to the relative misalignment or cause of the discharge ports corresponding to the respective colors. Generally, the configuration to be performed is adopted. In the bidirectional recording, when a positional deviation occurs between the forward scanning and the backward scanning, the image quality deteriorates due to the deviation of the reciprocating recording position.

  2. Description of the Related Art Conventionally, there is known a technique for adjusting a recording position shift caused by a relative position shift between the discharge ports or the recording heads described above, and a positional shift (also referred to as registration) in bidirectional recording. This adjustment is referred to as registration adjustment (or correction) or registration tone (registration correction).

  For example, the registration adjustment technique described in Patent Document 1 reads a pattern recorded by a recording apparatus using a sensor in the apparatus, and adjusts various positional deviations based on the read result. This adjustment technique is called an automatic registration adjustment method because it is a technique that automatically adjusts rather than judging by the user.

  In an inkjet printing apparatus, by using an automatic registration adjustment method as described in Patent Document 1 as described above, accurate position adjustment (registration adjustment) can be performed by a relatively inexpensive detection mechanism. As a result, a printing apparatus with high cost performance can be provided.

Japanese Patent Laid-Open No. 10-329381

  However, in recent years, with further demands for higher image quality of recorded images, ink droplets ejected from the print head have become smaller, and higher accuracy has been required even in automatic registration adjustment systems. With such a request, the following problems have become apparent.

  That is, the influence of the unique situation when the print position adjustment pattern group is recorded cannot be ignored. For example, in a serial scan type ink jet printing apparatus, for print position adjustment by the vibration of the carriage that moves with the print head mounted, the inclination of the paper (printed medium) in the main scanning direction, and the deviation of the paper feed amount and position The density unevenness occurs in the print result of the pattern group. The influence of such density unevenness cannot be ignored in detecting the optimum adjustment value (registration value) of the print position.

  When the ink droplet was not so small as before, the amount of deviation of the landing position of the ink droplet generated under such a unique situation was small compared to the size of the ink dot formed on the paper. The influence on the density of the pattern group for print position adjustment was relatively small. However, as the ink droplets become smaller, the influence of the deviation amount of the landing positions of the ink droplets on the density of the print position adjustment pattern group increases. When the impact of the landing position of the ink droplet is affected, the print position adjustment accuracy cannot be obtained sufficiently.

  As a matter of course, as the ink droplets become smaller, the mechanical accuracy of the mechanical components in the printing apparatus is improved in order to ensure image quality during normal printing. However, a highly accurate configuration that covers even a phenomenon under a specific situation is not preferable from the viewpoint of cost performance.

  On the other hand, adjustment values acquired for print position adjustment (registration adjustment) are continuously used in normal printing. For this reason, this is not a problem that occurs only in a specific situation, but it also affects normal printing.

  The object of the present invention is to avoid the influence of print defects caused by specific disturbances such as vibration during movement of the print head, tilt of the print medium, and misalignment of the print medium at the print position facing the print head. An object of the present invention is to provide a printing position adjustment method and printing apparatus that can perform printing position adjustment with high accuracy.

The print position adjusting method of the present invention is a print position adjusting method for adjusting a print position in movement in a first direction of a print head and a print position in movement in a second direction opposite to the first direction. In the same movement of the head in the first direction, the step of printing the plurality of first print position adjustment patterns and the plurality of first abnormality detection patterns, and the movement of the print head in the same second direction The second print position adjustment pattern is printed with a different amount of deviation for each of the plurality of first print position adjustment patterns, and the same deviation is obtained for each of the plurality of first abnormality detection patterns. Forming a second abnormality detection pattern in a quantity, and the first and second print position adjustment patterns. Measuring optical characteristics of a plurality of print position adjustment patterns and optical characteristics of a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns; and the plurality of print position adjustment patterns Obtaining a print position adjustment value based on a print position adjustment pattern excluding the print position adjustment pattern corresponding to the abnormality detection pattern having an abnormal measured optical characteristic among the patterns. It is characterized by.

A printing apparatus according to the present invention is a printing apparatus that performs printing by moving a print head in a first direction and a second direction opposite to the first direction. In the movement of the print head in the same first direction, , Printing a plurality of first print position adjustment patterns and a plurality of first abnormality detection patterns, and the plurality of first print position adjustment patterns when the print head moves in the same second direction. The second print position adjustment pattern is printed with a different shift amount for each pattern, and the second abnormality detection pattern is printed with the same shift amount for each of the plurality of first abnormality detection patterns. Optical characteristics of a plurality of print position adjustment patterns formed by the printing means and the first and second print position adjustment patterns; Measuring means for measuring optical characteristics of a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns, and the measured optical characteristics of the plurality of print position adjustment patterns are abnormal. Acquiring an adjustment value of a print position based on a print position adjustment pattern excluding the print position adjustment pattern corresponding to the abnormal detection pattern.

  The present invention prints a print abnormality detection pattern group in synchronization with printing of a print position adjustment pattern group, and adjusts the print position in consideration of the print result of the print abnormality detection pattern group. High-precision print position by avoiding the effects of print defects caused by specific disturbances such as vibration during movement, tilt of the print medium, and misalignment of the print medium at the print position facing the print head You can make adjustments.

  Hereinafter, embodiments of the present invention will be described.

(Basic configuration example of inkjet printing apparatus)
1 to 4 are views for explaining a basic configuration example of an ink jet printing apparatus to which the present invention can be applied.

  FIG. 1 is a perspective view showing a configuration example of a color ink jet printing apparatus to which the present invention can be applied, and shows a state in which the front cover is removed and the inside of the apparatus is exposed.

  In FIG. 1, 1000 is a replaceable ink jet cartridge, and 2 is a carriage unit that detachably holds the ink jet cartridge 1000. Reference numeral 3 denotes a holder for fixing the ink jet cartridge 1000 to the carriage unit 2. When the cartridge fixing lever 4 is operated after the ink jet cartridge 1000 is mounted in the carriage unit 2, the ink jet cartridge 1000 is pressed against the carriage unit 2 in conjunction with this operation. By this pressure contact, the inkjet cartridge 1000 is positioned, and at the same time, the required signal transmission electrical contact provided on the carriage unit 2 and the electrical contact on the inkjet cartridge 1000 side are connected. Reference numeral 5 denotes a flexible cable for transmitting an electric signal to the carriage unit 2.

  Reference numeral 30 denotes a reflective optical sensor, which is a print position adjustment pattern group (hereinafter also referred to as “adjustment pattern group”) recorded on a sheet (printed medium) in a print position automatic adjustment system (automatic registration adjustment system). ) To detect the recording density. The density of the adjustment pattern group printed on the paper is adjusted by feeding the paper in the sub-scanning direction (arrow Y direction) and moving the carriage to which the optical sensor 30 is attached in the main scanning direction (arrow X direction). Can be detected. The sensor 30 may also be used as a detection unit for detecting the edge of the paper.

  Reference numeral 6 denotes a carriage motor as a drive source for reciprocally scanning the carriage unit 2 in the main scanning direction, and reference numeral 7 denotes a carriage belt for transmitting the power of the carriage motor 6 to the carriage unit 2. Reference numeral 11 denotes a guide shaft extending in the main scanning direction, which supports the carriage unit 2 and guides it so as to be movable in the main scanning direction. Reference numeral 9 denotes a transmissive photocoupler attached to the carriage unit 2, and reference numeral 10 denotes a light shielding plate provided in the vicinity of a predetermined carriage home position. A home position unit 12 includes a recovery system such as a cap member for capping the front surface of the ink jet print head, a suction means for sucking the inside of the cap member, and a member for wiping the front surface of the print head.

  Reference numeral 13 denotes a discharge roller for discharging paper (a medium to be printed). The discharge roller cooperates with a spur roller (not shown) to sandwich the paper and discharges it outside the printing apparatus. A line feed unit 14 conveys a predetermined amount of paper in the sub-scanning direction.

  FIG. 2A is a perspective view showing details of the head cartridge 1000.

  Reference numeral 15 denotes an ink tank containing black (Bk) ink, and 16 denotes an ink tank containing cyan (C), magenta (M) and yellow (Y) inks, which can be attached to and detached from the ink jet cartridge body. It is like that. Reference numeral 17 denotes a connection port on the ink tank 16 side, which corresponds to the ink supply pipe 20 on the ink jet cartridge main body side that introduces each color ink stored in the ink tank 16. Reference numeral 18 denotes a connection port on the ink tank 15 side, which corresponds to an ink supply pipe on the ink jet cartridge main body side into which black ink stored in the ink tank 15 is introduced. Ink can be supplied to the print head 1 held in the ink jet cartridge main body by connecting the connecting ports 17 and 18 to the corresponding ink supply pipes on the ink jet cartridge main body side. Reference numeral 19 denotes an electrical contact portion, which can receive an electrical signal from the control portion of the printing apparatus main body via the flexible cable 5 by connection with the electrical contact portion provided on the carriage unit 2.

  In this example, a print head 1 is used in which a Bk ink discharge section in which nozzles for discharging Bk ink are arranged and a color ink discharge section are arranged in parallel. In the color ink discharge section, nozzle groups for discharging Y, M, and C inks are formed integrally and inline, respectively, and arranged in the Bk nozzle arrangement range.

  FIG. 2B is a schematic perspective view showing the main part of the main part structure of the print head 1 of the head cartridge 1000.

  In the print head 1, a plurality of discharge ports 22 are formed at a predetermined pitch on a discharge port surface 21 facing a sheet with a predetermined gap (for example, about 0.5 to 2.0 mm). An electrothermal converter (such as a heating resistor) 25 for generating thermal energy used for ink ejection is disposed along the wall surface of each liquid passage 24 that communicates with each ejection port 22 and the common liquid chamber 23. It is installed. The head cartridge 1000 of this example is mounted on the carriage 2 so that the ejection ports 22 of the print head 1 are aligned in a direction intersecting the scanning direction of the carriage 2. Based on the image signal or the ejection signal, the corresponding electrothermal converter (hereinafter also referred to as “ejection heater”) 25 is driven to cause the ink in the liquid path 24 to boil. Ink can be ejected from the ejection port 22 by the pressure of the generated bubbles.

  FIG. 3 is a schematic diagram for explaining the reflective optical sensor 30.

  The reflective optical sensor 30 includes a light emitting unit 31 and a light receiving unit 32. Light 35 emitted from the light emitting unit 31 is reflected by the paper (print medium) 8, and the reflected light 37 is detected by the light receiving unit 32. The detection signal of the light receiving unit 32 is transmitted as information on the electric board of the printing apparatus. In order to detect the density of the adjustment pattern group printed on the paper 8 to be equal to the human appearance, the light incident angle and the reflection angle are made different to detect irregularly reflected light.

  In this example, for the purpose of adjusting the print position (registration adjustment) for all the print heads responsible for discharging the inks of C, M, Y, and K, the light emitting unit 31 has a white LED or a three-color LED. And a photodiode having sensitivity to visible light is used for the light receiving unit 32. In addition, when detecting the density of a print image corresponding to the relationship between two print positions to be aligned, if two print positions with different inks are to be aligned, a color with high detection sensitivity can be selected and emitted. It is preferable to use a three-color LED for the light emitting portion 31.

  The optical sensor 30 does not need to detect an absolute value of density, and has a performance that can detect a relative density difference for each pattern (hereinafter also referred to as “patch”) belonging to the adjustment pattern group. That's fine. Regarding the stability of the detection system in the optical sensor 30, it is sufficient that the optical sensor system has such a degree of stability that does not affect the detected density difference until the detection of each patch of the adjustment pattern group. The sensitivity adjustment of the optical sensor 30 is performed, for example, by moving the optical sensor 30 to a non-printed portion of the paper, and adjusting the current of the LED as the light emitting unit 31 so that the detection level becomes the upper limit at the moving position, or a detection amplifier Do this by adjusting the gain. Such sensitivity adjustment is not essential, but it is desirable to improve the detection accuracy by improving the S / N ratio.

  The resolution of the sensor 30 is desirably a resolution that can detect an area smaller than the print area of one adjustment pattern group. In multi-pass printing, when two adjustment pattern groups are printed so as to be adjacent to each other in a direction orthogonal to the main scanning direction, the print width in the sub-scanning direction is reduced according to the number of passes. The resolution of the sensor 30 is limited. Further, the number of print passes (print width) may be determined from the resolution of the sensor 30.

  FIG. 4 is a schematic block diagram of a control system in the printing apparatus.

  In FIG. 4, the CPU 100 executes control processing of the operation of the printing apparatus, data processing, and the like. The ROM 101 stores programs such as those processing procedures, and the RAM 102 is used as a work area for executing these processes. Ink is ejected from the print head 1 by the CPU 100 supplying drive data (image data) and drive control signals (heat pulse signals) of the heating elements 25 to the head driver 1A. The CPU 100 controls the carriage motor 103 for driving the carriage in the main scanning direction via the motor driver 103A, and the P.C. The F motor 104 is controlled via the motor driver 104A.

  Further, as will be described later, the CPU 100 executes print position adjustment processing (registration adjustment processing) using the optical sensor 30. The function of this adjustment process can also be provided on the host device 200 side.

(Example of basic print position adjustment)
Next, an example (similar to the prior art) of basic print position adjustment (registration adjustment) will be described. In this example, two print positions at the time of forward scanning and backward scanning of a predetermined print head are set as alignment targets.

  First, a print head to be aligned is selected, and the print head is used to print the first adjustment pattern group by forward scanning in the main scanning direction, and then overlap the first adjustment pattern group. In addition, the second adjustment pattern group is printed by the backward scanning in the main scanning direction. In each of the first and second adjustment pattern groups, for example, a plurality of 10 mm square patches are arranged in the main scanning direction, and the patches corresponding to each other in the first and second adjustment pattern groups are printed so as to overlap each other. Is done. In the combination of patches printed so as to overlap each other, the print position of one set of patches is shifted by one dot at the time of forward scanning and the time of backward scanning, and the other one set of patches is at the time of forward scanning and backward scanning The print position is shifted by 2 dots, and the print position of the other set of patches is shifted by 3 dots during forward scanning and backward scanning. In this way, the print positions during forward scanning and backward scanning in each set of patches are shifted by one dot.

  In the printing process of these adjustment pattern groups, for example, the same adjustment pattern group is used as the first and second adjustment pattern groups. After the first adjustment pattern group is printed by forward scanning, the second adjustment pattern group is printed by backward scanning. Print the adjustment pattern. When printing the second adjustment pattern, the ink ejection timing from the print head is adjusted, and the print position during forward scanning and backward scanning of each set of patches as described above in units of one dot. Shift by different amounts. Normally, printing a plurality of sets of patches shifted by one dot unit is sufficient for detecting the print position adjustment value. In that case, for example, an adjustment pattern group shifted in units of one dot is created in advance, and the configuration can be simplified by printing it.

  Next, each patch is read by the optical sensor 20 as the carriage moves.

  That is, while moving the carriage at a constant speed, the density of each patch, that is, the density of each patch printed by the forward scanning and the backward scanning as described above, is read by the optical sensor 20, and the detected value is a circuit. Transmit to the processing unit on the substrate. In the processing section, the detection signal of the optical sensor 20 is A / D converted and stored as a patch density value. The reason for scanning the optical sensor 20 at a constant speed is to stabilize the posture of the carriage to ensure reading accuracy, and to perform spatial filtering on each patch simultaneously by reading while moving.

  Thereafter, the print condition for the patch having the lowest density among the patches is adopted as the optimum resist adjustment value. However, depending on how the offsets (print position shifts) of the first and second adjustment pattern groups are given, the print condition for the patch having the highest density may be adopted as the optimum resist adjustment value, or may be adjacent. In some cases, an optimum registration adjustment value may be obtained by performing interpolation / calculation processing on a plurality of patches positioned at a position based on print conditions.

(Differences between the print position adjustment example according to the present invention and the basic print position adjustment example)
Next, differences between the print position adjustment example of the present invention and the basic registration adjustment example described above will be described. Also in this example, two print positions at the time of forward scanning and backward scanning of a predetermined print head are set as alignment targets. Details of the print position adjustment example according to the present invention will be described later.

  In the automatic print position adjustment (automatic registration adjustment) of this example, during the same scanning, a registration adjustment pattern group as a first set of adjustment pattern group and a print abnormality detection pattern group as a second set of adjustment pattern group Is printed. The first set of adjustment pattern groups corresponds to a combination of the first and second adjustment pattern groups in the basic print position adjustment example described above. In the main scanning direction, printing is performed so that the patch portions in the first and second sets of pattern groups are arranged, and in the sub-scanning direction, printing is performed so that the patch portions in the first and second sets of pattern groups are adjacent to each other. To do.

  Then, using the optical sensor 30 mounted on a main scanning member such as a carriage as shown in FIG. 3, the optical sensor 30 is scanned so as to pass over the printed adjustment pattern groups, and each set of adjustment patterns. Detect the optical properties (density) of the patch part in the county.

  As will be described later, the optical characteristics of each patch portion in the second set of adjustment pattern groups are acquired by scanning the optical sensor 30 on the second set of adjustment pattern groups (abnormality detection pattern groups). Then, the optical characteristics for each patch portion are compared with the average of the optical characteristics. If there is a patch portion (hereinafter also referred to as “abnormal patch portion”) having an optical characteristic whose difference from the latter average optical characteristic is larger than a predetermined threshold value, an ink droplet is printed at the print position of the abnormal patch portion. It is determined that the landing position deviation of has occurred. Then, the patch portion in the first set of adjustment pattern groups printed at the same time as the abnormal patch portion is not used for calculation of the resist adjustment value, and other patch portions in the first set of adjustment pattern groups are used. A resist adjustment value is calculated.

(Example of print position adjustment according to the present invention)
Next, an example of print position adjustment in the embodiment of the present invention will be described more specifically. Also in this example, two print positions at the time of forward scanning and backward scanning of a predetermined print head are targeted for alignment, and as described above, the resist adjustment pattern group is printed as the first set of adjustment pattern groups. The print abnormality detection pattern group is printed as the second set of adjustment pattern groups.

  FIG. 5 is an explanatory diagram of the print format of the adjustment pattern group in this example. In this example, in order to simplify the description, a case will be described in which an adjustment pattern group is printed by reciprocal bidirectional printing using eight adjacent nozzles 202 in the recording head 201. Naturally, the pattern group printed by the ink droplets 203 ejected from such a small number of nozzles is not suitable for density detection because it is small. In actual use, such printing is performed in the nozzle row direction.

  Among the eight nozzles 202, the above-described first and second adjustment pattern groups are printed as the first set of adjustment pattern groups A by the upper four nozzles. That is, the first adjustment pattern group is printed during forward scanning, and the second adjustment pattern group is printed during backward scanning. Further, an abnormality detection pattern group, which will be described later, is printed as a second set of adjustment pattern group B by the lower four nozzles.

  6A to 6C are schematic diagrams of patch portions in the first set of adjustment pattern group A. FIG.

  In the patch portions of FIGS. 6A to 6C, the dots drawn with white circles are ink dots that are formed on the print medium during forward scanning in order to print the first adjustment pattern group A1. The dots drawn with black circles are ink dots formed on the print medium during the backward scan in order to print the second adjustment pattern group A2. 6A to 6C, monochrome dots are used for convenience of explanation. However, in the present embodiment, each dot is formed by ink ejected from the same print head and does not correspond to the color or darkness of the dot.

  FIG. 6A is an explanatory diagram of patch portions in which the print positions of the first and second adjustment pattern groups A1 and A2 are matched among the plurality of patch portions in the first set of adjustment pattern group A. FIG. FIG. 6B is an explanatory diagram of a patch portion where the print positions of both are slightly shifted, and FIG. 6C is an explanatory diagram of a patch portion where the print positions of both are further shifted.

  The first set of adjustment pattern group A in this example is set so that the print position shift of the first and second adjustment pattern groups A1 and A2 becomes large, and therefore the density of the entire print portion is lowered. Yes. That is, in FIG. 6A, the area factor covered by the dots is about 100%. As shown in FIGS. 6B and 6C, as the print position is shifted, the first adjustment pattern group A1 dots (outlined dots) formed during the forward scanning and the second dots formed during the backward scanning. The overlap of the dots (black dots) of the adjustment pattern group A2 increases, and an area that is not printed, that is, an area that is not covered by the dots spreads.

  The intended purpose of the first set of adjustment pattern group A is to reduce the area factor as the print positions during forward scanning and backward scanning shift greatly from each other. The print density strongly depends on the area factor. Therefore, the increase in the unprinted area has a greater influence on the overall density than the density increase due to the overlapping of dots.

  FIG. 7 is an explanatory diagram of the second set of adjustment pattern group B as the print abnormality detection pattern group.

  In this example, the adjustment pattern group B is configured in a lattice pattern so that the print density decreases when the ink droplet does not land at a predetermined position on the print medium. This adjustment pattern group B is a combination of a first adjustment pattern B1 printed during forward scanning and a second adjustment pattern B2 printed during backward scanning. In the case of this example, the lattice-shaped adjustment pattern group B is distributed to the first and second adjustment pattern groups B1 and B2 in raster units. The method of allocating the adjustment pattern group B to the first and second adjustment pattern groups B1 and B2 is not specified only for each raster unit as in this example, and may be any unit such as a column. Further, the adjustment pattern group B itself is not limited to a lattice shape. In short, it is sufficient that the print density changes when the ink droplet does not land at a predetermined position on the print medium.

  The relative positional relationship between the first and second adjustment pattern groups B1 and B2 is fixed in all of the plurality of patch portions in the second set of adjustment pattern groups B. When there is no deviation in the print positions of the first and second adjustment pattern groups B1 and B2, dots are formed in the black square portions in FIG. 7 to obtain a predetermined print density. On the other hand, when the print positions are shifted, the print density changes (decreases in this example) according to the degree of the shift. Accordingly, each patch portion in the second set of adjustment pattern group B is individually reflected in the print position shift of the first and second adjustment pattern groups B1 and B2 when the patch portions are printed. become.

  FIG. 8 is an explanatory diagram of a print example of the first set and the second set of adjustment pattern groups A and B. FIG.

  In the case of this example, nine patches (a) to (i) are printed along the main scanning direction, and the upper side of each patch is the patch portion of the first set of adjustment pattern group A. The lower side is the patch portion of the second adjustment pattern group B.

  After printing the adjustment pattern group, the optical characteristics of the adjustment pattern groups A and B for each patch (a) to (i) are acquired by scanning the optical sensor 20 on the adjustment pattern group. . Then, the average of the optical characteristics of the patch portions of the adjustment pattern group B in each patch (a) to (i) is calculated, and the average optical characteristics are compared with the individual optical characteristics of the patch portions of the adjustment pattern group B. To do. If there is a patch portion (hereinafter also referred to as “abnormal patch portion”) having an optical characteristic whose difference from the former average optical characteristic is larger than a predetermined threshold, an ink droplet is printed at the print position of the abnormal patch portion. It is determined that the landing position deviation of has occurred. The patch portion of the adjustment pattern group A printed at the same time as the abnormal patch portion is not used for calculating the registration adjustment value.

  When it is determined that the landing position deviation has occurred in a part of the abnormal patch part, as described later, without using the optical characteristic data of the patch part of the adjustment pattern group A printed simultaneously with the abnormal patch part, Using the optical characteristic data of other patch portions in the adjustment pattern group A, a resist adjustment value is calculated. On the other hand, if it is determined that the landing position deviation has occurred in the entire area of the abnormal patch portion, the registration adjustment value is set in the same manner as in the above case (when it is determined that the landing position deviation has occurred in a part of the abnormal patch portion). In addition to the calculation method (hereinafter also referred to as “first calculation method”), as will be described later, a method of calculating the resist adjustment value by correcting the optical characteristics of the adjustment pattern group A with the optical characteristics of the adjustment pattern group B (Hereinafter, also referred to as “second calculation method”) can be selected.

  FIG. 9 is a diagram for explaining the first and second calculation methods.

(First calculation method)
The white circles in FIG. 9C indicate the measurement data of the optical characteristics of each patch part in the adjustment pattern group B, and the patch part P1 is an abnormal patch part. The white circles in FIGS. 9A and 9B indicate the measurement data of the optical characteristics of each patch part in the adjustment pattern group A, and DA-1 is the optical characteristic data of the patch part corresponding to the abnormal patch part P1. is there.

  PA in FIG. 9A is a resist adjustment value calculated using measurement data of optical characteristics of other patch portions without using the optical property data DA-1 corresponding to the abnormal patch portion P1. PA ′ in FIG. 9B is a registration adjustment value calculated using the optical characteristic data DA-1 corresponding to the abnormal patch portion P1. The registration adjustment value PA ′ calculated without considering the influence of the landing position deviation in the abnormal patch portion P1 is different from the actual registration adjustment value, and there is a possibility that high-precision registration adjustment cannot be performed. Therefore, in this example, the registration adjustment value PA is calculated without using the optical characteristic data DA-1 in consideration of the influence of the landing position deviation in the abnormal patch portion P1. Thereby, a highly accurate registration adjustment value can be calculated.

(Second calculation method)
A polynomial approximate curve CA ′ (x) in FIG. 9B is calculated from optical characteristic measurement data (including data DA-1) of each patch portion in the adjustment pattern group A. Similarly, a polynomial approximate curve CB (x) in FIG. 9C is calculated from the measurement data of the optical characteristics of each patch portion in the adjustment pattern group B. Here, x is a variable indicating a position in the main scanning direction. Further, the approximate curve of the measurement data of the adjustment pattern group A not including the data DA-1, that is, the registration adjustment curve in which the influence of the landing position deviation is reduced is CA (x) (FIG. 9A).

The resist adjustment curve CA (x) can be calculated by the following equation (1).
CA (x) = CA ′ (x) −CB (x) (1)

  The resist adjustment curve A (x) is a continuous change characteristic curve, and the printing condition of the patch portion showing the minimum value or the maximum value is set as the optimum alignment condition. In this way, by adjusting the optical characteristic data of the first set of adjustment pattern group A using the optical characteristics acquired from the second set of adjustment pattern group B, the resist adjustment value that reduces the influence of the landing position deviation. Can be calculated.

(Other examples of adjustment pattern group B)
As the second set of adjustment pattern group B, an adjustment pattern group is used in which, when the landing position is shifted in either the main scanning direction or the sub-scanning direction, the density varies depending on the degree of the shift. be able to.

  As shown in FIG. 10, the adjustment pattern group B of this example includes a pattern portion X (B) whose density changes due to a deviation of the landing position in the main scanning direction (X direction), and a landing position in the sub scanning direction (Y direction). Pattern portion Y (B) in which the density changes due to the deviation. The pattern portion X (B) is a combination of the first adjustment pattern group X (B1) printed at the time of forward scanning and the second adjustment pattern group X (B2) printed at the time of backward scanning. . The relative positional relationship between these adjustment pattern groups X (B1) and X (B2) is fixed in all of the plurality of patch portions in the second set of adjustment pattern groups B. Similarly, the pattern portion Y (B) is a combination of the first adjustment pattern group Y (B1) printed during forward scanning and the second adjustment pattern group Y (B2) printed during backward scanning. Is. The relative positional relationship between these adjustment pattern groups Y (B1) and Y (B2) is also fixed in all of the plurality of patch portions in the second set of adjustment pattern groups B.

  Using such an adjustment pattern group B, as in the case described above, the patch portion where the landing position deviation has occurred is determined as an abnormal patch portion. In the case of this example, a patch portion in which a landing position deviation of a predetermined threshold value or more occurs in either the main scanning direction or the sub-scanning direction is determined as an abnormal patch portion. That is, a patch portion in which a deviation of the landing position of a predetermined threshold value or more in either pattern portion X (B) or X (Y) is determined as an abnormal patch portion.

  FIG. 11 is an explanatory diagram of a patch portion on which the pattern portion X (B) is printed. The patch portion in FIG. 11A is a patch portion where the print positions of the first and second adjustment pattern groups X (B1) and X (B2) are aligned. The patch portion in FIG. 11B is a patch portion where the print positions of both are slightly shifted, and the patch portion in FIG. 11C is a patch portion where the print positions of both are further shifted. Thus, the density of the pattern portion X (B) changes due to the deviation of the landing position in the main scanning direction.

  Also in this example, similarly to the case described above, when it is determined that the landing position deviation has occurred in a part of the abnormal patch portion, the adjustment pattern group A printed at the same time as the abnormal patch portion is described later. The resist adjustment value is calculated using the optical characteristic data of other patch portions in the adjustment pattern group A without using the optical characteristic data of the patch portion. On the other hand, if it is determined that the landing position deviation has occurred in the entire area of the abnormal patch portion, the registration adjustment value is set in the same manner as in the above case (when it is determined that the landing position deviation has occurred in a part of the abnormal patch portion). In addition to the calculation method (hereinafter also referred to as “first calculation method”), as will be described later, a method of calculating the resist adjustment value by correcting the optical characteristics of the adjustment pattern group A with the optical characteristics of the adjustment pattern group B (Hereinafter, also referred to as “second calculation method”) can be selected.

  In the first calculation method, as described above, the optical characteristic data of other patch portions in the adjustment pattern group A is used without using the optical characteristic data of the patch portion of the adjustment pattern group A printed at the same time as the abnormal patch portion. A registration adjustment value is calculated using the data. Thereby, a highly accurate registration adjustment value can be obtained.

  On the other hand, in the second calculation method, the optical characteristic data of the adjustment pattern group A is corrected using the optical characteristics acquired from the adjustment pattern group B. In the case of this example, polynomial approximate curves BX (x) and BY (x) are calculated from measurement data of optical characteristics in the X direction and Y direction in each patch portion of the adjustment pattern group B. Here, x is a variable indicating a position in the main scanning direction. The adjustment pattern group A is greatly affected by the displacement of the landing position in the X direction or the Y direction according to the pattern. In the case of the adjustment pattern group A as shown in FIG.

When the adjustment pattern group A is easily affected by the landing position deviation in the X direction, the registration adjustment curve CA (x) in which the influence of the landing position deviation in the X direction is reduced can be calculated by the following equation (2). it can. CA ′ (x) is a polynomial approximation curve calculated from optical characteristic measurement data (including data DA-1) of each patch portion in the adjustment pattern group A as shown in FIG. 9B described above.
CA (x) = CA ′ (x) −BX (x) (2)

Further, when the adjustment pattern group A is easily affected by the landing position deviation in the Y direction, the registration adjustment curve CA (x) in which the influence of the landing position deviation in the Y direction is reduced is calculated by the following equation (3). be able to.
CA (x) = CA ′ (x) −BY (x) (3)

  As described above, in the second calculation method, the resist adjustment value in which the influence of the landing position deviation is reduced by correcting the optical characteristic data of the adjustment pattern group A using the optical characteristic acquired from the adjustment pattern group B. Can be calculated.

(Still another example of adjustment pattern group B)
As the second set of adjustment pattern group B, a pattern group for printing the same patches as the patches in the first set of adjustment pattern group A can be used. However, the print timings are set so that the print positions of the same patch in the adjustment pattern groups A and B are different.

  12A shows measurement data of optical characteristics of patches (a) to (h) in the adjustment pattern group A, and FIG. 12B shows patches of the patches (a) to (h) in the adjustment pattern group B. The measurement data of optical characteristics is shown. In the case of this example, the patches of the adjustment pattern groups A and B printed at the same position are shifted by 3 patches. For example, the former patch (a) and the latter patch (f) are printed at the same position. . Therefore, data having different phases can be acquired as the optical characteristic data of the adjustment pattern groups A and B. If there is no abnormality, both data should have the same value with different phases. However, when the landing position deviation of the ink droplet occurs, a difference occurs between the data of both.

  FIG. 12 shows a case where a landing position deviation occurs in the patch (f) of the adjustment pattern group A and the patch (c) of the adjustment pattern group B printed at the same timing. It can be determined from the comparison with the patch (f) of the corresponding adjustment pattern group B that the landing position deviation has occurred in the former patch (f), and the landing position deviation has occurred in the latter patch (c). The occurrence can be determined from a comparison with the patch (a) of the corresponding adjustment pattern group A.

  When calculating the registration adjustment value from the optical characteristic data of the adjustment pattern group A in FIG. 12A, the data of the patch (f) in which the landing position deviation has occurred is not used, but instead of the adjustment pattern group B. The data of patch (f) is used. As a result, it is possible to obtain a registration adjustment value that eliminates the effect of landing position deviation.

  Note that the method of making the print positions of the same patches different in the adjustment pattern groups A and B is not limited to the above-described example and is arbitrary, and these patches may be associated with each other. Further, the patches of the adjustment pattern group B are not necessarily the same as the patches of the adjustment pattern group A, and are not necessarily the same as the number of patches of the adjustment pattern group B. In short, it is only necessary that the patches of the adjustment pattern group B can be used in place of the patch data of the adjustment pattern group A in which the landing position deviation occurs because both patches have a predetermined relationship.

(Other)
In the example described above, the first adjustment pattern group A1 in the first set of adjustment pattern group A is printed by one forward scan (one pass) of the print head 201, and the second adjustment pattern group A2 is Printing was performed by one backward scanning (one pass) of the print head 201. Similarly, each of the first and second adjustment pattern groups in the second set of adjustment pattern group B was printed by one forward scan (one pass) and one backward scan (one pass).

  However, each adjustment pattern group may be printed using different nozzles by a multi-pass method of two or more passes.

  FIG. 13 is an explanatory diagram of a multi-pass method in which each adjustment pattern group is printed by two passes.

  For example, in the adjustment pattern group A1 in the first set of adjustment pattern group A, half of the area is printed using the nozzles 202-1 and 202-2 at the first forward scanning, and the nozzle 202- at the second forward scanning. The remaining half of the area is printed using 5,202-6. In the adjustment pattern group A2, half of the area is printed using the nozzles 202-1 and 202-2 during the first backward scanning, and the remaining areas are printed using the nozzles 202-5 and 202-6 during the second backward scanning. Half of the area is printed. Similarly, the first and second adjustment pattern groups in the second set of adjustment pattern group B are printed by the main scanning and the backward scanning twice. In this way, when printing is performed by two passes, the print area of each adjustment pattern group is halved as compared with the case of printing by one pass as shown in FIG.

The number of passes for printing the adjustment pattern group may be set according to the resolution of the sensor 30, or the resolution of the sensor 30 may be determined according to the number of passes. Further, by printing the adjustment pattern groups A and B so as to be adjacent to each other, it is possible to reduce the influence of the inclination of the nozzle during the scanning of the carriage.
Further, by printing the adjustment pattern groups A and B during the same scan, when a specific landing position deviation occurs in one scan, it is possible to obtain a resist adjustment that avoids the influence of the landing position deviation. When such a specific landing position deviation occurs, in order to efficiently detect the landing position deviation amount, the impact on the adjustment pattern groups A and B due to the landing position deviation may be approximately the same. desirable. Therefore, it is desirable that the density of the adjustment pattern groups A and B printed during the same scanning in the multi-pass method be approximately the same.

  Further, the print position to be adjusted in the present invention is not limited to the print position at the time of forward scanning and at the time of backward scanning as described above. For example, the print position by different print heads that eject different or the same kind of ink can be adjusted.

It is explanatory drawing of the basic structural example of the inkjet printing apparatus which can apply this invention. 1A is an exploded perspective view of a head cartridge in the ink jet printing apparatus of FIG. 1, and FIG. 2B is an enlarged perspective view of an ejection portion in the head cartridge. It is a schematic diagram of the optical sensor mounted in the inkjet printing apparatus of FIG. It is a block block diagram for demonstrating the control system of the inkjet printing apparatus of FIG. It is explanatory drawing of an example of the printing format of the adjustment pattern group in this invention. (A) is an explanatory diagram of a patch whose print position is matched, (B) is an explanatory diagram of a patch whose print position is slightly shifted, and (C) is an explanatory diagram of a patch whose print position is further shifted. It is explanatory drawing of the print pattern of the 2nd set of adjustment pattern group in this invention. It is explanatory drawing of the example of a print of the 1st set and 2nd set of adjustment pattern group in this invention. It is explanatory drawing of the measurement data of the adjustment pattern group in this invention. It is explanatory drawing of the other example of the adjustment pattern group in this invention. 10A is an explanatory diagram of a patch in which the print position of the adjustment pattern in FIG. 10 is matched, FIG. 10B is an explanatory diagram of a patch whose print position is slightly shifted, and FIG. 10C is a print position that is further shifted. It is explanatory drawing of a patch. It is explanatory drawing of the measurement data of the further another example of the adjustment pattern group in this invention. It is explanatory drawing of the other example of the print format of the adjustment pattern group in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Print head 2 Carriage unit 8 Medium to be printed 30 Reflection type optical sensor 31 Light emission part 32 Light reception part 35 Irradiation light 37 Reflection light 100 CPU
101 ROM
102 RAM
200 Host device 201 Print head 202 Nozzle A First set of adjustment pattern group (print position adjustment pattern group)
A1, A2 adjustment pattern (position adjustment pattern)
B Second set of adjustment pattern group (print abnormality detection pattern group)
B1, B2 Adjustment pattern (abnormality detection pattern)

Claims (6)

A print position adjustment method for adjusting a print position in movement in a first direction of a print head and a print position in movement in a second direction opposite to the first direction ,
Printing the plurality of first print position adjustment patterns and the plurality of first abnormality detection patterns in the same movement of the print head in the first direction;
In the same movement of the print head in the second direction, a second print position adjustment pattern is printed with a different amount of shift with respect to each of the plurality of first print position adjustment patterns, and the plurality of first print position adjustment patterns is printed. Printing a second abnormality detection pattern with the same amount of deviation for each of the abnormality detection patterns;
Optical characteristics of a plurality of print position adjustment patterns formed by the first and second print position adjustment patterns, and a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns. Measuring optical properties; and
Of the plurality of print position adjustment patterns, a print position adjustment value is obtained based on the print position adjustment pattern excluding the print position adjustment pattern corresponding to the abnormality detection pattern having an abnormal measured optical characteristic. And a process of
A print position adjusting method comprising: A print position adjustment method for adjusting a print position in movement in a first direction of a print head and a print position in movement in a second direction opposite to the first direction ,
Printing the plurality of first print position adjustment patterns and the plurality of first abnormality detection patterns in the same movement of the print head in the first direction;
In the same movement of the print head in the second direction, a second print position adjustment pattern is printed with a different amount of shift with respect to each of the plurality of first print position adjustment patterns, and the plurality of first print position adjustment patterns is printed. Printing a second abnormality detection pattern with the same amount of deviation for each of the abnormality detection patterns;
Optical characteristics of a plurality of print position adjustment patterns formed by the first and second print position adjustment patterns, and a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns. Measuring optical properties; and
Acquiring print position adjustment values based on the optical characteristics of the plurality of print position adjustment patterns corrected based on the optical characteristics of the plurality of abnormality detection patterns;
A print position adjusting method comprising: The plurality of print position adjustment patterns and the plurality of abnormality detection patterns are printed side by side in the movement direction of the print head,
3. The print position adjustment method according to claim 1, wherein the print position adjustment pattern and the abnormality detection pattern are printed adjacent to each other in a direction that intersects a moving direction of the print head. The abnormality detection pattern is a pattern having different optical characteristics when the print position is shifted in the direction of movement of the print head or in the direction intersecting with the direction of movement of the print head and when the print position is not shifted. The print position adjusting method according to claim 1, wherein the print position is adjusted. A printing apparatus for performing printing by moving a print head in a first direction and a second direction opposite to the first direction ,
In the same movement of the print head in the first direction, a plurality of first print position adjustment patterns and a plurality of first abnormality detection patterns are printed, and the print head moves in the same second direction. The second print position adjustment pattern is printed with a different amount of deviation for each of the plurality of first print position adjustment patterns, and the same deviation is obtained for each of the plurality of first abnormality detection patterns. Printing means for printing the second abnormality detection pattern in an amount;
Optical characteristics of a plurality of print position adjustment patterns formed by the first and second print position adjustment patterns, and a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns. Measuring means for measuring optical properties;
Of the plurality of print position adjustment patterns, a print position adjustment value is obtained based on the print position adjustment pattern excluding the print position adjustment pattern corresponding to the abnormality detection pattern having an abnormal measured optical characteristic. To get and
A printing apparatus comprising: A printing apparatus for performing printing by moving a print head in a first direction and a second direction opposite to the first direction ,
In the same movement of the print head in the first direction, a plurality of first print position adjustment patterns and a plurality of first abnormality detection patterns are printed, and the print head moves in the same second direction. The second print position adjustment pattern is printed with a different amount of deviation for each of the plurality of first print position adjustment patterns, and the same deviation is obtained for each of the plurality of first abnormality detection patterns. Printing means for printing the second abnormality detection pattern in an amount;
Optical characteristics of a plurality of print position adjustment patterns formed by the first and second print position adjustment patterns, and a plurality of abnormality detection patterns formed by the first and second abnormality detection patterns. Measuring means for measuring optical properties;
Obtaining means for obtaining an adjustment value of a print position based on optical characteristics of the plurality of print position adjustment patterns corrected based on optical characteristics of the plurality of abnormality detection patterns;
A printing apparatus comprising:

Images