Printing apparatus production method

Abstract

To produce a printing apparatus in which a printing unit is adjusted with high accuracy.SOLUTION: A printing apparatus production method of producing an adjusted printing apparatus from a serial ink jet type printing apparatus before adjustment includes: printing at least two first markers using black ink; and printing at least two second markers using chromatic color ink, where the second markers have a shape in which the chromatic color ink is applied to a region where the black ink is not applied in the first markers in a case where the center positions of the first markers and the second markers coincide with each other; and identifying a position of an inspection pattern on an inspection sheet on the basis of the positions of the markers determined by analysis.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a method for producing a printing apparatus.

Background Art

[0002] Conventionally, a technique for detecting a printing error by scanning a printed medium on which a specific inspection pattern is printed is known. Patent Document 1 discloses a technique for correctly specifying the size, position, and inclination of an adjustment pattern (inspection pattern).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the inspection sheet, inspection patterns for correcting printing errors such as media conveyance deviation (PF deviation, Paper Feed deviation) and dot formation position deviation (Bi-D) caused by relative positional movement during reciprocation in the main scanning direction between the printing unit and the medium are printed. Furthermore, there are cases where it is desired to confirm the presence or absence of nozzle clogging using the inspection pattern. In such cases, the inspection sheet includes an inspection pattern for inspecting nozzle clogging. When the nozzle clogging is not eliminated, the inspection pattern for correcting other printing errors cannot be printed correctly. Therefore, it is desired to reliably detect the inspection pattern for nozzle clogging.

Means for Solving the Problems

[0005] In view of the above problems, the present invention provides a printing apparatus production method for producing an adjusted printing apparatus by causing a printing apparatus before adjustment of a serial inkjet system to print an inspection sheet including an inspection pattern, causing a scanning unit to read the inspection sheet, analyzing the read inspection sheet, and adjusting the printing apparatus before adjustment based on the inspection pattern detected by the analysis. The method includes printing at least two first markers using black ink and printing at least two second markers using colored ink. The second markers are shaped such that when the center positions of the first markers and the second markers are aligned, the colored ink is applied to an area of the first markers where the black ink is not applied. Based on the positions of the markers determined by the analysis, the position of the inspection pattern on the inspection sheet is specified.

Brief Description of the Drawings

[0006]

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Embodiments for Carrying Out the Invention

[0007] (First Embodiment) FIG. 1 is a configuration diagram of the multifunction machine 10 according to the first embodiment. The multifunction machine 10 has a printing function and a scanner function. Note that the multifunction machine 10 may be provided with other functions such as a FAX. The multifunction machine 10 is an example of a printing device. The multifunction machine 10 includes a printing unit 11, a scanning unit 12, a processor 13, a non-volatile memory 14, a UI unit 15, a communication unit 16, and a cleaning unit 17. The printing unit 11 includes a print head 111, a carriage 112, and a transport mechanism 113.

[0008] The multifunction machine 10 of this embodiment is assumed to perform monochrome printing. The print head 111 includes one nozzle row corresponding to black (K) ink and performs printing by a serial inkjet method. The nozzle row includes a plurality of nozzles, and ink is ejected from each nozzle. The ink of each nozzle is supplied from an ink tank (not shown) or the like. By ejecting ink from each nozzle of the print head 111, ink droplets (dots) are formed on the medium (paper).

[0009] The print head 111 is mounted on the carriage 112. The carriage 112 reciprocates along a specific direction under the control of the processor 13. Accordingly, the print head 111 reciprocates in a specific direction. The direction in which the print head 111 reciprocates is referred to as the main scanning direction. The transport mechanism 113 is a device that transports the medium to be printed. The transport mechanism 113 transports the paper in a direction perpendicular to the main scanning direction of the print head 111. Here, the direction perpendicular to the main scanning direction of the print head 111, that is, the direction in which the paper is transported, is referred to as the sub-scanning direction.

[0010] In the nozzle array of the print head 111, a plurality of nozzles are arranged at equal intervals along the sub-scanning direction. By repeating the ejection of ink from the nozzles during the reciprocating movement of the print head 111 and the conveyance of the medium by the conveyance mechanism 113, printing on the medium is performed. The cleaning unit 17 cleans the ink clogging of the nozzles by sucking the ink.

[0011] The scanning unit 12 includes a light source and a light receiving element that receives light from the object to be scanned. In the scanning unit 12 of the present embodiment, a CMOS (Complementary Metal Oxide Semiconductor) line sensor of the CIS (Contact Image Sensor) method is used. As another example, the scanning unit 12 may be a sensor of the CCD (Charge Coupled Device) method. Hereinafter, the arrangement direction of the light receiving elements in the line sensor is referred to as the main scanning direction of the scanning unit 12.

[0012] As shown in FIG. 2, the multifunction machine 10 includes a media table 122 provided with a glass surface 121 on which the object P to be read is placed. That is, the multifunction machine 10 includes a flatbed type scanning device including the scanning unit 12, the glass surface 121, and the media table 122. The scanning unit 12 moves in a direction B perpendicular to the main scanning direction A on the glass surface 121 under the control of the processor 13. Hereinafter, the direction perpendicular to the main scanning direction is referred to as the sub-scanning direction of the scanning unit 12. The scanning unit 12 repeats the reading while moving by a predetermined amount in the sub-scanning direction, thereby reading the entire object P.

[0013] In the present embodiment, it is assumed that the relative position of the object P and the scanning unit 12 changes as the scanning unit 12 moves with respect to the placed object P. However, as another example, the relative position may change by conveying the medium in the sub-scanning direction by the conveyance mechanism 113 with respect to the fixed scanning unit 12.

[0014] The processor 13 includes a RAM, a CPU, etc. The non-volatile memory 14 stores various data and programs. The processor 13 can execute the programs stored in the non-volatile memory 14. The UI unit 15 includes an input unit for receiving user input and a display unit for displaying various information to the user. The communication unit 16 communicates with external devices such as a PC or a tablet terminal connected by wired communication, wireless communication, etc.

[0015] In the multifunction machine 10 of this embodiment, the printing unit 11 prints an inspection pattern on a medium. Here, the inspection pattern is an image in which a predetermined pattern is shown at a predetermined position. The multifunction machine 10 can scan the inspection sheet on which this inspection pattern is printed and perform image analysis to adjust the control content of the printing unit 11. Examples of the adjustment include correction of media conveyance deviation (PF deviation, Paper Feed deviation) and correction of dot formation position deviation (Bi-D) caused by relative positional movement during reciprocation in the main scanning direction between the printing unit 11 and the media. Note that the object of adjustment only needs to be adjustable based on the inspection pattern, and is not limited to the embodiment. For example, in this embodiment, the inspection pattern also includes a nozzle inspection pattern for checking the presence or absence of nozzle clogging. When it is detected from the nozzle inspection pattern that nozzle clogging has occurred, cleaning by the cleaning unit 17 is performed as an adjustment of the printing unit 11.

[0016] The processor 13 of this embodiment includes a print control unit 131, a scan control unit 132, a detection unit 133, and an adjustment unit 134 as a functional configuration for adjusting the settings of the printing unit 11 using the inspection pattern. The functions of the print control unit 131, the scan control unit 132, the detection unit 133, and the adjustment unit 134 are realized by the processor 13 reading and executing the programs stored in the non-volatile memory 14. That is, hereinafter, the processes described as being executed by the print control unit 131, the scan control unit 132, the detection unit 133, and the adjustment unit 134 are the processes executed by the processor 13.

[0017] The printing control unit 131 controls the printing unit 11. The scanning control unit 132 controls the scanning unit 12. The detection unit 133 detects a predetermined marker or inspection pattern in the scanned image. The detection unit 133 further performs matching by comparing the detected marker and inspection pattern with the corresponding reference marker and reference pattern respectively. It should be noted that the reference marker and reference pattern referred to in the matching process are assumed to be stored in the non-volatile memory 14 in advance. The adjustment unit 134 adjusts the settings of the printing unit 11 based on the detection result by the detection unit 133.

[0018] FIG. 3 is a diagram showing an example of an inspection sheet. The print head 111 prints an inspection pattern on the inspection sheet 200 under the control of the printing control unit 131. In the inspection sheet 200, among the sides parallel to the main scanning direction, the side printed first is referred to as the upper side, and the other side is referred to as the lower side. Also, among the sides parallel to the sub-scanning direction, when the inspection sheet 200 with the upper side positioned upward is viewed from the front, the right side is referred to as the right side, and the other side is referred to as the left side.

[0019] On the inspection sheet 200, a nozzle inspection pattern 210 for checking the presence or absence of nozzle clogging and other inspection patterns 221 to 223 are printed. The nozzle inspection pattern 210 is a pattern for checking the presence or absence and degree of nozzle clogging. The other inspection patterns 221 to 223 are patterns for adjusting control contents such as the above-mentioned medium conveyance deviation and dot formation position deviation.

[0020] On the upper part of the inspection sheet 200, a plurality of nozzle markers 231 to 238, which are markers for specifying the positions of the nozzle inspection patterns 210, are printed. In the vicinity of the nozzle inspection pattern 210, a plurality of position and inclination markers 251 to 254 for correcting the position and inclination of the nozzle inspection pattern 210 are printed. Also, in the vicinity of the other inspection pattern 221, a plurality of position and inclination markers 261 to 264 for specifying the position of the other inspection pattern 221 are printed. Similarly, position and inclination markers 271 to 276 are printed in the vicinity of the other inspection patterns 222 and 223. The image data of these nozzle markers 231 to 238, the nozzle inspection pattern 210, the other inspection patterns 221 to 223, and the position and inclination markers 251 to 254, 261 to 264, 271 to 276 are assumed to be pre-stored in the non-volatile memory 14. As another example, these image data may be stored in an external device and transmitted from the external device to the multifunction machine 10.

[0021] The nozzle markers 231 to 238 are arranged at predetermined relative positions based on the nozzle inspection pattern 210 so as to have a known positional relationship with respect to the nozzle inspection pattern 210. Specifically, the nozzle markers 231 to 234 are printed in the left region 241 on the upper side and the left side (end side) of the nozzle inspection pattern 210. The nozzle markers 234 to 238 are printed in the right region 242 on the upper side and the right side (end side) of the nozzle inspection pattern 210.

[0022] Both the left region 241 and the right region 242 are arranged on the left - right direction of the inspection sheet 200, closer to the ends than the nozzle inspection pattern 210 and the other inspection patterns 221 - 223. That is, all of the nozzle markers 231 - 238 are printed closer to the ends than the nozzle inspection pattern 210 and the other inspection patterns 221 - 223 in the left - right direction of the inspection sheet 200. In this way, by arranging each of the nozzle markers 231 - 238 at the end sides, the accuracy of position detection using the nozzle markers 231 - 238 can be improved. Note that the nozzle markers 231 - 238 do not necessarily have to be printed closer to the ends than each of the position inclination markers 251 - 254, 261 - 264, 271 - 276.

[0023] For the nozzle inspection pattern 210, four position inclination markers 251 - 254 are arranged at different positions respectively. Specifically, the position inclination markers 251 - 254 are arranged at the vertices of a rectangle with the main scanning direction and the sub - scanning direction as two sides outside the nozzle inspection pattern 210. In this way, the four position inclination markers 251 - 254 are arranged to form a rectangle with a known size.

[0024] And the relationship (relative position relationship) between the position of the position inclination marker 251 and the upper - left vertex of the nozzle inspection pattern 210 is preset. Therefore, the processor 13 can perform pattern detection of the nozzle inspection pattern 210 using the position of the position inclination marker 251 as a reference.

[0025] The relative position relationship (relative positional relationship) between the position of the position and inclination marker 251 and the upper left vertex of the nozzle inspection pattern 210 is preset. Therefore, the processor 13 can perform pattern detection of the nozzle inspection pattern 210 using the position of the position and inclination marker 251 as a reference. Furthermore, as described above, based on the sizes of the four rectangular position inspection markers and the size of a known rectangle, the processor 13 can identify the presence or absence of distortion, inclination, etc. in the scanned image and perform appropriate correction. Similarly, position and inclination markers 271 to 276 are arranged around the other inspection patterns 221 to 223, and based on these, the other inspection patterns 222 and 223 can be detected and appropriately corrected.

[0026] FIG. 4 is an explanatory diagram of a nozzle row and nozzle markers 231 to 238. In the present embodiment, the nozzle markers 231 to 238 all have a double-ring shape and are of the same size and the same shape.

[0027] As described above, the nozzle markers 231 to 238 are printed separately in the left region 241 and the right region 242 of the inspection sheet 200. Furthermore, each of the nozzle markers 231 to 238 is printed by a specific nozzle group. In the present embodiment, the plurality of nozzles 301 included in the nozzle row 300 of the print head 111 are divided into four nozzle groups (first nozzle group 311 to fourth nozzle group 314), and one nozzle marker in the left region 241 and one nozzle marker in the right region 242 are printed by the same nozzle group.

[0028] In this embodiment, the plurality of nozzles 301 are divided into four nozzle groups: a first nozzle group 311, a second nozzle group 312, a third nozzle group 313, and a fourth nozzle group 314. Each nozzle group includes nozzles that are different from each other. In this embodiment, among the 16 nozzles, the 1st to 4th nozzles are included in the first nozzle group 311, the 5th to 8th nozzles are included in the second nozzle group 312, the 9th to 12th nozzles are included in the third nozzle group 313, and the 13th to 16th nozzles are included in the fourth nozzle group 314. Although some nozzles can belong to multiple nozzle groups, it is better that there are no nozzles that commonly belong to multiple nozzle groups as in this embodiment.

[0029] Then, by each nozzle group, one nozzle marker in the left region 241 and one nozzle marker in the right region 242 are printed. Hereinafter, a combination of one nozzle marker in the left region 241 and one nozzle marker in the right region 242 printed by the same nozzle group is referred to as a marker set.

[0030] In this embodiment, first, the nozzle markers 231 and 238 are printed by the first nozzle group 311. Subsequently, the paper is fed, and the nozzle markers 232 and 237 are printed by the second nozzle group 312. Subsequently, the paper is fed, and the nozzle markers 233 and 236 are printed by the third nozzle group 313. Subsequently, the paper is fed, and the nozzle markers 234 and 235 are printed by the fourth nozzle group 314.

[0031] In the following, for convenience of explanation, the nozzle markers 231 and 238 printed by the first nozzle group 311 are referred to as the first A marker and the first B marker, respectively, and these are referred to as the first marker set. Also, the nozzle markers 232 and 237 printed by the second nozzle group 312 are referred to as the second A marker and the second B marker, respectively, and these are referred to as the second marker set. Also, the nozzle markers 233 and 236 printed by the third nozzle group 313 are referred to as the third A marker and the third B marker, respectively, and these are referred to as the third marker set. Also, the nozzle markers 234 and 235 printed by the fourth nozzle group 314 are referred to as the fourth A marker and the fourth B marker, respectively, and these are referred to as the fourth marker set.

[0032] Furthermore, in the present embodiment, the printing unit 11 prints two nozzle markers included in the same marker set in the same pass. That is, the printing unit 11 prints the first A marker and the first B marker in the same pass, and prints the second A marker and the second B marker in the same pass. Furthermore, the printing unit 11 prints the third A marker and the third B marker in the same pass, and prints the fourth A marker and the fourth B marker in the same pass. Thereby, it is possible to prevent the positions of the two nozzle markers in the same marker set from shifting in the sub-scanning direction due to different passes.

[0033] Also, in the present embodiment, the printing unit 11 prints all the markers (the first A marker, the first B marker, the second A marker, the second B marker, the third A marker, the third B marker, the fourth A marker, the fourth B marker) in the same row, that is, at equal positions in the sub-scanning direction. Thereby, the range occupied by each nozzle marker on the inspection sheet 200 can be reduced.

[0034] The detection unit 133 detects the nozzle markers 231 to 238. Here, the processing of the detection unit 133 will be described. The detection of the nozzle markers 231 to 238 is performed by pattern matching with the image data (reference markers) of the nozzle markers stored in the non-volatile memory 14 in advance. In the pattern matching, the detection unit 133 sets a range of a predetermined number of pixels based on the upper left vertex as a comparison region in the scanned image, and compares with the reference marker in each comparison region while shifting the comparison region pixel by pixel.

[0035] Specifically, the detection unit 133 compares the pixel values (luminance) of the corresponding pixels in the comparison region and the reference marker. Then, the detection unit 133 obtains the total value of the absolute values of the differences of the respective pixel values (luminance) obtained by the comparison. In the case of a perfect match, theoretically, the total value of the differences becomes zero. The detection unit 133 obtains a match rate based on the total value of the differences. The match rate is a value that is 100% when the total value of the differences is zero and becomes smaller as the total value of the differences increases. Then, the detection unit 133 detects the comparison region where the match rate is maximum as the range of any one of the nozzle markers 231 to 238, and specifies the center of this range as the nozzle marker position.

[0036] The detection unit 133 of the present embodiment specifies the position of the nozzle inspection pattern 210 by triangulation using two nozzle markers included in the marker set. In this way, by using the nozzle markers arranged in the left region 241 and the right region 242, the distance between the markers becomes relatively large, so that the detection accuracy of the nozzle inspection pattern 210 can be improved.

[0037] If one marker set is detected, the position of the nozzle inspection pattern 210 can be specified based on the positional relationship between the two nozzle markers included in the detected marker set. However, if nozzle clogging has occurred in any of the plurality of nozzles 301, the nozzle markers cannot be printed correctly. Therefore, the multifunction device 10 of the present embodiment prints a plurality of marker sets using each nozzle group. As a result, even if nozzle clogging has occurred in any of the nozzle groups, if the marker set is printed correctly by another nozzle group, the nozzle inspection pattern 210 can be detected.

[0038] However, since all the nozzle markers are of the same size and the same shape, the detection unit 133 cannot determine which of the eight nozzle markers the detected nozzle marker is. Therefore, in the present embodiment, the printing position of each nozzle marker is determined at a position such that the distance between the two nozzle markers included in each marker set (marker-to-marker distance) becomes a unique length. Therefore, the detection unit 133 can determine which nozzle marker has been detected based on the marker-to-marker distance.

[0039] FIG. 5 is a diagram showing the marker-to-marker distances for all combinations of the nozzle markers in the left region 241 and the nozzle markers in the right region 242. These marker-to-marker distances are registered in the non-volatile memory 14 in association with the corresponding two nozzle markers. In the present embodiment, the first A marker, the second A marker, the third A marker, and the fourth A marker are arranged at positions 3, 5, 8, and 12 from the left side, respectively, and the first B marker, the second B marker, the third B marker, and the fourth B marker are arranged at positions 42, 46, 49, and 51 from the left side, respectively. As a result, the marker-to-marker distance between the first A marker and the first B nozzle marker is 48.

[0040] In addition, the marker-to-marker distance between the second A marker and the second B marker is 44, the marker-to-marker distance between the third A marker and the third B marker is 38, and the marker-to-marker distance between the fourth A marker and the fourth B marker is 30. These marker-to-marker distances are different from the marker-to-marker distances of any other two nozzle markers. For example, the marker-to-marker distance between the third A marker and the first B marker is 43, which is equal to the marker-to-marker distance between the first A marker and the third B marker. Thus, the marker-to-marker distance between two nozzle markers other than the marker set corresponding to each nozzle group may be equal to the marker-to-marker distance between the other two nozzle markers.

[0041] As described above, in this embodiment, the marker-to-marker distance between the two nozzle markers included in each marker set on the inspection sheet 200 is defined as a unique length. More specifically, the marker-to-marker distance between the two nozzle markers in each marker set is made different from the marker-to-marker distances of any other two nozzle markers. Thereby, the detection unit 133 can determine which nozzle marker has been detected based on the marker-to-marker distance.

[0042] FIG. 6 and FIG. 7 are explanatory diagrams of the detection process of the marker set. For example, as shown in FIG. 6, assume that the first and second nozzles and the fifth to twelfth nozzles are clogged. In this case, as shown in FIG. 6, half of the first A marker and the first B marker are printed. Also, the second A marker, the second B marker, the third A marker, and the third B marker are not printed. The fourth A marker and the fourth B marker are printed normally. And in the matching by the detection unit 133, as shown in FIG. 6, the matching rate is 50% for the first A marker and 49% for the first B marker. The matching rates of the second A marker, the second B marker, the third A marker, and the third B marker are all 0%. The matching rate of the first A marker is 99%, and the matching rate of the first B marker is 98%. When the recognition accuracy (threshold value) available for the position detection of the nozzle inspection pattern 210 is set to 60% or more, the available marker set is only the fourth marker set.

[0043] In this case, the detection unit 133 can obtain the marker-to-marker distance 30 based on the detection positions of the two nozzle markers. As shown in FIG. 7, the marker-to-marker distance becomes 30 only for the fourth marker set of the fourth A marker and the fourth B marker. Therefore, the detection unit 133 determines that the detected nozzle markers are the fourth A marker and the fourth B marker based on the marker-to-marker positions.

[0044] Next, a production method of the multifunction machine 10 as a printing apparatus will be described. In the production method of the present embodiment, the multifunction machine 10 after adjustment (completed) is produced by performing adjustment using an inspection pattern on the multifunction machine 10 before adjustment (incomplete). Here, in the incomplete multifunction machine 10, mechanical parts and electrical parts are assembled and can perform a printing operation, but the adjustment related to printing has not been performed. By the production method, the adjustment related to printing is performed, and a completed product of the multifunction machine 10 is obtained. Note that the production method may be performed as a part of the production process in a factory or may be performed after installation of the incomplete multifunction machine 10 at the customer site.

[0045] The production method includes an inspection sheet printing process and an inspection sheet reading process. FIG. 8 is a flowchart showing the inspection sheet printing process. FIG. 9 is a flowchart showing the inspection sheet reading process. As shown in FIG. 8, in the inspection sheet printing process, first, paper is fed to the multifunction machine 10 by the user (step S100). Next, various markers of the inspection sheet 200 are printed by the printing unit 11 of the incomplete multifunction machine 10 (step S102), and various inspection patterns of the inspection sheet 200 are printed by the printing unit 11 (step S104). Note that the printing of the various markers and the various inspection patterns is performed in order from the top of the paper along the sub-scanning direction in accordance with the conveyance of the medium while the print head 111 moves in the main scanning direction. Thereby, the printing of the inspection sheet is completed.

[0046] Next, with reference to FIG. 9, the inspection sheet reading process will be described. The inspection sheet is set on the glass surface 121 by the user, and a user operation for starting the scan is performed. In response to this, the scan control unit 132 starts driving the scan unit 12 and reads the upper part of the inspection sheet 200 (step S200). Here, the upper part is a preset range that includes the positions of the nozzle markers 231 to 238, and is a preset range in the sub-scanning direction of the scan unit 12.

[0047] Next, the detection unit 133 detects the nozzle markers in the left area 241 in the scan image obtained in step S200 (step S202). Specifically, the detection unit 133 detects the nozzle markers in the left half range of the scan image read in step S200. Subsequently, the detection unit 133 detects the nozzle markers in the right area 242 in the scan image obtained in step S200 (step S204). Specifically, the detection unit 133 detects the nozzle markers in the right half range in the main scanning direction of the scan image read in step S200.

[0048] Next, in step S206, the detection unit 133 determines whether at least one or more nozzle markers have been detected in each of the left area 241 and the right area 242 (step S206). Note that the detection unit 133 determines that a nozzle marker has been detected when the matching rate is equal to or higher than a threshold value (for example, 60%).

[0049] If one or more nozzle markers cannot be detected in at least one of the left area 241 and the right area 242 (N in step S206), the process is aborted. In this case, since there is a possibility that the inspection sheet is upside down or the front and back are reversed, the processor 13 notifies the user of an error in the UI unit 15.

[0050] If one or more nozzle markers are detected in either the left region 241 or the right region 242 (Y in step S206), the detection unit 133 calculates the distance between markers for all combinations of the nozzle markers in the left region 241 and the nozzle markers in the right region 242 (step S208).

[0051] Next, the detection unit 133 checks whether there is a marker - to - marker distance with a unique length among the calculated distances. For example, in the example described with reference to FIGS. 4 and 5, the distances 48, 44, 38, and 30 are unique lengths. If a marker - to - marker distance with a unique length is obtained, the two detected nozzle markers are determined to be a marker set associated with the unique length. If there is no marker - to - marker distance with a unique length (N in step S210), the detection unit 133 cannot detect the nozzle markers and cannot detect the nozzle inspection pattern 210, so the process is aborted.

[0052] If there is a marker - to - marker distance with a unique length (Y in step S210), the detection unit 133 selects the marker set with the longest marker - to - marker distance (step S212). Next, the detection unit 133 specifies the position of the nozzle inspection pattern 210 based on the detection positions of the two nozzle markers included in the marker set selected in step S212 (step S214). The relative positional relationship between the two nozzle markers in all marker sets (four marker sets in the examples of FIGS. 4 and 5) and the nozzle inspection pattern 210 is preset. Then, by referring to this positional relationship, the detection unit 133 specifies the position (range) of the nozzle inspection pattern 210 based on the detection positions of the two nozzle markers.

[0053] In this way, in the present embodiment, since the detection unit 133 specifies the position of the nozzle inspection pattern 210 using the marker set with the longest marker - to - marker distance, the position of the nozzle inspection pattern can be specified more accurately.

[0054] Next, the detection unit 133 detects the nozzle inspection pattern 210 by reading the position specified in step S214 (step S216). Next, the adjustment unit 134 adjusts the nozzle 301 based on the detection result of the nozzle inspection pattern 210 (step S218).

[0055] Specifically, the adjustment unit 134 causes the cleaning process of the nozzle 301 to be executed according to the matching result between the nozzle inspection pattern 210 and a reference pattern preset corresponding to the nozzle inspection pattern 210. Specifically, when the matching rate with the nozzle inspection pattern is equal to or higher than a first threshold value, the adjustment unit 134 determines that cleaning is not required. When the matching rate is less than the first threshold value and equal to or higher than a second threshold value, the adjustment unit 134 causes the cleaning unit 17 to perform low-intensity cleaning. Also, when the matching rate is less than the second threshold value, the adjustment unit 134 causes the cleaning unit 17 to perform high-intensity cleaning. Here, the second threshold value is a value smaller than the first threshold value, and when the cleaning intensity is high, the suction force becomes larger compared to when the intensity is low. When the degree of nozzle clogging is large, the nozzle inspection pattern 210 cannot be printed accurately, so the matching rate becomes low. Therefore, in this way, the adjustment unit 134 performs nozzle cleaning with an intensity corresponding to the matching rate, that is, an intensity corresponding to the nozzle clogging situation.

[0056] Subsequently, while using the position inclination markers 261 to 274, the processor 13 reads the other inspection patterns 221 to 223 to perform other adjustment processes (step S220). In the other adjustment processes, the processor 13 generates adjustment parameters for the printing unit 11 based on the detection results of the other inspection patterns 221 to 223 and stores them in the non-volatile memory 14. Thus, the adjustment of the multifunction machine 10 is completed, and the production of the completed multifunction machine 10 is completed.

[0057] As described above, even when nozzle clogging occurs in some nozzles, the multifunction machine 10 of the present embodiment can surely detect a nozzle inspection pattern. Further, by making the shapes of the nozzle markers for detecting the nozzle inspection pattern the same size and the same shape, the matching process can be speeded up. Further, by making the distance between the markers in each marker set a unique length, it is possible to determine which marker set the two detected nozzle markers belong to.

[0058] A first modification of the first embodiment will be described. In the first embodiment, each nozzle group includes different nozzles, but one nozzle may be included in a plurality of nozzle groups. For example, the first to fifth nozzles may be included in the first nozzle group, the fifth to ninth nozzles may be included in the second nozzle group, the ninth to thirteenth nozzles may be included in the third nozzle group, and the twelfth to sixteenth nozzles may be included in the fourth nozzle group.

[0059] As a second modification, in the present embodiment, a plurality of nozzles are divided into four nozzle groups, and four marker sets are printed on the inspection sheet. However, the number of divisions of the nozzles is not limited to the embodiment. The plurality of nozzles may be divided into two or more nozzle groups, and two or more marker sets may be printed. That is, the plurality of nozzles may be divided into three nozzle groups, and three marker sets may be printed. The plurality of nozzles may be divided into five or more nozzle groups, and five or more marker sets may be printed.

[0060] (Second Embodiment) Next, the multifunction machine 10 according to the second embodiment will be mainly described with respect to the differences from the multifunction machine 10 according to the first embodiment. The print head 111 of the multifunction machine 10 according to the second embodiment includes nozzle rows corresponding to four types of colored inks of CMYK (C: cyan, M: magenta, Y: yellow, K: black), and performs printing by an inkjet method.

[0061] Figure 10 is an explanatory diagram of nozzle arrays of respective colors and nozzle markers in the second embodiment. In the second embodiment, on the inspection sheet 200, similarly to the first embodiment, the first nozzle markers 281 to 288 are printed with K ink. Further, the second nozzle markers 291 to 298 made of composite black are printed with C ink, M ink, and Y ink. The first nozzle markers 281 to 284 and the second nozzle markers 291 to 294 are printed in the left region 241. The first nozzle markers 285 to 288 and the second nozzle markers 295 to 298 are printed in the right region 242.

[0062] The first nozzle markers 281 to 288 are an example of the first marker, and the second nozzle markers 291 to 298 are an example of the second marker. Also, the second nozzle markers 291 to 298 may be markers printed with at least one chromatic marker.

[0063] The first nozzle markers 281 to 288 made of K ink are all in the shape of a double ring with no ink applied to the center, and are markers of the same size and the same shape. Also, the second nozzle markers 291 to 298 made of chromatic ink are all markers of the same size and the same shape, with a black-filled circle arranged at the center and a ring arranged around it. The second nozzle marker 291 formed with chromatic ink is a marker shaped such that when the center position coincides with the first nozzle marker 281 printed with K ink, the area where ink is applied does not overlap with the first nozzle marker 281.

[0064] Note that the second nozzle marker 291 only needs to be shaped such that when the center position coincides with the first nozzle marker 281 printed with K ink, ink is applied to the area where no ink is applied to the first nozzle marker 281, and is not limited to the embodiment. For example, the second nozzle marker 291 may have a portion overlapping with the first nozzle marker 281. For example, the second nozzle marker 291 may be a triangular double ring.

[0065] Also in this embodiment, the plurality of nozzles included in each color nozzle row are divided into three nozzle groups: the first nozzle group to the fourth nozzle group. Then, by the K ink of the first nozzle group 321, the first nozzle marker 281 (first A marker) and the first nozzle marker 288 (first B marker) are printed. Further, by the C ink, M ink, and Y ink of the first nozzle group 321, the composite black second nozzle markers 291 and 298 are printed. Hereinafter, the second nozzle markers 291 and 298 are referred to as the fifth A marker and the fifth B marker, respectively, and these are referred to as the fifth marker set. Similarly, by the K ink of the second nozzle group 322, the first nozzle marker 282 (second A marker) and the first nozzle marker 287 (second B marker) are printed. Then, by the C ink, M ink, and Y ink of the second nozzle group 322, the composite black second nozzle markers 292 and 297 are printed. Hereinafter, the second nozzle markers 292 and 297 are referred to as the sixth A marker and the sixth B marker, respectively, and these are referred to as the sixth marker set.

[0066] By the K ink of the third nozzle group 323, the first nozzle marker 283 (third A marker) and the first nozzle marker 286 (third B marker) are printed. Then, by the C ink, M ink, and Y ink of the third nozzle group 323, the composite black second nozzle markers 293 and 296 are printed. Hereinafter, the second nozzle markers 293 and 296 are referred to as the seventh A marker and the seventh B marker, respectively, and these are referred to as the seventh marker set. By the K ink of the fourth nozzle group 324, the first nozzle marker 284 (fourth A marker) and the first nozzle marker 285 (fourth B marker) are printed. Then, by the C ink, M ink, and Y ink of the fourth nozzle group 324, the composite black second nozzle markers 294 and 295 are printed. Hereinafter, the second nozzle markers 294 and 295 are referred to as the eighth A marker and the eighth B marker, respectively, and these are referred to as the eighth marker set.

[0067] In this embodiment, the printing unit 11 prints two nozzle markers included in the same marker set in the same pass. Further, the printing unit 11 prints all the marker sets at the same position in the same row, that is, in the sub-scanning direction.

[0068] Furthermore, the 5A marker and the 5B marker are printed at positions that are a certain distance to the left of the 1A marker and the 1B marker, respectively. Similarly, the 6A marker and the 6B marker are printed at positions that are a certain distance to the left of the 2A marker and the 2B marker, respectively. Furthermore, the 7A marker and the 7B marker are printed at positions that are a certain distance to the left of the 3A marker and the 3B marker, respectively, and the 8A marker and the 8B marker are printed at positions that are a certain distance to the left of the 4A marker and the 4B marker, respectively.

[0069] FIG. 11 is a diagram showing the distance between markers. FIG. 11(a) shows the distance between the markers of the first nozzle markers 281 to 288 printed with K ink. FIG. 11(b) shows the distance between the markers of the second nozzle markers printed with colored ink. Also in this embodiment, it is assumed that the marker sets of the first to fourth marker sets all have a unique marker-to-marker distance. Then, as shown in FIG. 11(b), for the second nozzle markers 291 to 298 of composite black as well, it is assumed that the marker sets of the fifth to eighth marker sets all have a unique marker-to-marker distance.

[0070] That is, the distance between the two first-nozzle markers in each of the first to fourth marker sets is different from the distance between any other two first-nozzle markers formed by K ink. Also, the distance between the two second-nozzle markers in each of the fifth to eighth marker sets is different from the distance between any other two second-nozzle markers formed by colored ink. Thereby, the detection unit 133 can determine which nozzle marker has been detected based on the distance between the markers. Note that, as in the case of the distance between the markers of the first marker set and the fourth marker set, among markers with different shapes, there may be cases where the distances between the markers are equal.

[0071] Furthermore, in the present embodiment, the detection unit 133 detects the first-nozzle markers 281 to 288 formed by K ink, obtains the distance between the markers from the detection results, and when a unique length is obtained, detects the nozzle inspection pattern 210 based on the unique length. Then, when the detection unit 133 can detect the nozzle inspection pattern 210 based on the first-nozzle markers 281 to 288 formed by K ink, the detection and matching processes for the second-nozzle markers 291 to 298 formed by colored ink are not performed. On the other hand, when the detection unit 133 cannot detect the nozzle inspection pattern 210 based on the first-nozzle markers 281 to 288 formed by K ink, the detection unit 133 detects the second-nozzle markers 291 to 298 formed by colored ink and obtains the distance between the markers from the detection results. Then, when a unique length is obtained, the detection unit 133 detects the nozzle inspection pattern 210 based on the unique length. Thereby, the nozzle inspection pattern 210 can be detected efficiently.

[0072] Figs. 12 and 13 are explanatory diagrams of the marker set detection process. For example, as shown in Fig. 12, it is assumed that the second A marker, the second B marker, the fourth A marker, and the fourth B marker are detected. In this case, as the marker-to-marker distances, 39, 46, and 32 are obtained. Among these, since the unique lengths are 46 and 32, it is determined that the second marker set and the fourth marker set corresponding to these are detected. Note that for the two marker sets, it is possible to determine which is the second marker set and which is the fourth marker set from the positional relationship between the two sets. Then, using the second marker set with the longest marker-to-marker distance, the nozzle inspection pattern 210 is detected. In the example shown in Fig. 12, the seventh A marker and the seventh B marker are also printed, but since the second marker set and the fourth marker set are detected, these markers are not detected.

[0073] Note that the other configurations and processes of the multifunction machine 10 according to the second embodiment are the same as those of the multifunction machine 10 according to the first embodiment.

[0074] A modification of the second embodiment will be described. As shown in Fig. 14, the print head 111 includes one nozzle row for K ink and one nozzle row for CMY color inks. When having such a print head 111, the nozzle row is divided into a first nozzle group 331, a second nozzle group 332, and a third nozzle group 333. The first nozzle group 331 includes the first to fourth nozzles for K ink and four nozzles for Y ink. The second nozzle group 332 includes the fifth to eighth nozzles for K ink and four nozzles for M ink. The third nozzle group 333 includes the ninth to twelfth nozzles for K ink and four nozzles for C ink.

[0075] Then, the first A marker and the first B marker are printed with the K ink of the first nozzle group 331. Subsequently, the second A marker and the second B marker are printed with the K ink of the second nozzle group 332, and the third A marker and the third B marker are printed with the K ink of the third nozzle group 333. On the other hand, the fourth A marker and the fourth B marker are printed with the Y marker of the first nozzle group 331, the M marker of the second nozzle group 332, and the C marker of the third nozzle group 333.

[0076] The above embodiments are examples for implementing the present invention, and various other embodiments can also be adopted. For example, various modifications and changes are possible within the scope of the gist of the present invention described in the claims, such as applying a modification of a certain embodiment to other embodiments.

[0077] Furthermore, the present invention is also applicable as a program or method executed by a computer. Also, it may be realized as a single device as described above, or may be realized by using components provided in a plurality of devices, and includes various aspects. Also, it can be appropriately changed, such as part being software and part being hardware. Furthermore, the invention is also established as a recording medium for a program that controls the system. Of course, the recording medium for the program may be a magnetic recording medium, a semiconductor memory, or any recording medium developed in the future, and can be considered in exactly the same way.

Explanation of Reference Numerals

[0078] 10... Multifunction device, 11... Printing unit, 12... Scanning unit, 13... Processor, 24... Non-volatile memory, 15... UI unit, 16... Communication unit, 17... Cleaning unit, 131... Printing control unit, 132... Scanning control unit, 133... Detection unit, 134... Adjustment unit

Claims

1. A method for producing a printing apparatus, which causes a printing apparatus before adjustment of a serial inkjet system to print an inspection sheet including an inspection pattern, causes a scanning unit to read the inspection sheet, analyzes the read inspection sheet, and adjusts the printing apparatus before adjustment based on the detected inspection pattern, thereby producing an adjusted printing apparatus, comprising: printing at least two first markers using black ink; printing at least two second markers using colored ink; the second marker having a shape in which the colored ink is applied to an area where the black ink is not applied in the first marker when the center positions of the first marker and the second marker are made to coincide; specifying the position of the inspection pattern on the inspection sheet based on the positions of the markers determined by the analysis.

2. The method for producing a printing apparatus according to claim 1, wherein, in the analysis, the position of the inspection pattern on the inspection sheet is specified based on the distance between two of the first markers detected on the inspection sheet or the distance between two of the second markers.

3. The method for producing a printing apparatus according to claim 1, wherein, in the analysis of the inspection sheet, when two of the first markers can be detected, the second marker is not detected.

4. The method for producing a printing apparatus according to claim 1, wherein the second marker is printed in composite black.

5. the first marker having a double-ring shape with no ink applied to the center; The method for producing a printing apparatus according to claim 1, wherein the second marker has a shape of a circle with ink applied to the center and a ring arranged around the circle.

6. The method for producing a printing apparatus according to claim 1, wherein the first marker and the second marker are printed at equal positions in the sub-scanning direction. Claim 7 The inspection pattern includes a nozzle inspection pattern indicating the clogging state of the nozzle, The method for manufacturing a printing apparatus according to claim 1, wherein adjustment of the printing apparatus includes cleaning the nozzle with an intensity corresponding to the clogging state of the nozzle.

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