JP7403368B2 - Abnormality detection method for inkjet printing device and its edge sensor - Google Patents

Description

The present invention relates to an inkjet printing device that uses a roll-shaped recording medium such as a web, and a method for detecting an abnormality in an edge sensor for detecting a side edge position of the recording medium in the inkjet printing device.

In an inkjet printing apparatus that uses a web as a recording medium, images are recorded by ejecting ink onto continuous paper, which is recording paper (recording medium) that is unwound from the web and transported. Such an inkjet printing device usually has four recording heads each consisting of first to fourth recording heads that eject K (black), C (cyan), M (magenta), and Y (yellow) inks, respectively. Various types of recording heads are provided, and these first to fourth recording heads are arranged in the conveyance direction of continuous paper.

In such an inkjet printing device, when the continuous paper that is unwound from the web and is conveyed meanderes, the landing position of the ejected ink may be misplaced from the target position, or the multiple colors that should constitute one pixel may be misaligned. The landing positions of the ink may shift from each other, resulting in color misregistration. To deal with this, an edge sensor (also called an "edge sensor") is installed to detect the position of the side edge of the continuous paper being conveyed. Conventionally, a configuration has been known in which the recording head is moved in the width direction of the continuous paper (this is a direction perpendicular to the conveyance direction of the continuous paper, hereinafter referred to as the "paper width direction") based on the detected value of the edge sensor. It is being Additionally, a configuration has been known in the past that corrects image data representing a printing target in order to change the printing position of the image to be printed so as to prevent color shift and the like.

In connection with the inkjet printing device disclosed in this application, the following Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-55570) discloses that an edge sensor (edge sensor) detects the meandering amount MJ caused when continuous paper is conveyed. The predicted waveform data HY is generated based on the measured waveform data HJ of the meandering amount MJ, and the print position of the image is corrected and applied to the print head based on the shift amount SF obtained based on the predicted waveform data HY. A printing device configured as described above is disclosed (see [Summary], paragraph [0031], etc.).

In addition, Patent Document 2 (Japanese Patent Laid-Open No. 2016-104553) below discloses an inkjet recording device that can prevent false detection of sensor failure and suppress decline in productivity due to downtime ( [Summary], paragraphs [0014], [0017], [0019], [0022] to [0024], etc.). In this inkjet recording apparatus, edge sensors 24 are provided for each line head (for each color) to detect the position of the edge of the recording paper for each line head (for each color), and the output of the edge sensor 24 is An abnormal range is set for each value. The outputs of each end sensor 24 are simultaneously grasped, and a failure of the end sensor 24 is determined based on the relationship between the outputs of each end sensor 24. For example, if only the end sensor (K sensor) corresponding to black is within the abnormal range at the abnormal value determination time, it is determined that the K sensor has failed. Further, if all the edge sensors 24 are within the abnormal range at the abnormal value determination time, it is determined that the conveyance position of the recording paper has changed (meandering) or that there is no paper.

Japanese Patent Application Publication No. 2016-55570 Japanese Patent Application Publication No. 2016-104553

As mentioned above, the edge sensor that detects the position of the side edge of the recording paper being conveyed in an inkjet printing device may not be able to provide the correct output value (detected value indicating the position of the side edge of the recording paper) due to the adhesion of dust such as paper dust. may not be possible. In this case, if the print position of the image is corrected based on the output value by modifying print data or adjusting the position of recording means such as a line head, color misregistration or the like will occur. In this way, whether or not an abnormality has occurred in the end sensor due to paper dust or the like cannot be determined from the output value alone. That is, in the inkjet printing device (inkjet recording device) described in Patent Document 2, failure of the edge sensor 24 is determined based on whether the output value of the edge sensor 24 is within the abnormal range. Considering the influence on the output value of the end sensor 24 by .

Therefore, in order to prevent color shift due to meandering of continuous paper on which an image is to be recorded in an inkjet printing apparatus, it is desirable to reliably detect an abnormality in an edge sensor that detects the side edge position of the continuous paper.

A first aspect of the present invention is an inkjet printing device, comprising:
a conveyance mechanism that conveys a long continuous recording medium unwound from a roll recording medium;
a recording unit that includes at least one recording head and records an image by ejecting ink from the at least one recording head onto the continuous recording medium;
The recording unit and the transport mechanism are configured such that an inspection pattern for detecting a deviation of a printing position on the continuous recording medium in the width direction of the continuous recording medium is recorded on the continuous recording medium together with an image to be printed. a recording control unit for controlling;
at least one edge sensor that detects a side edge position of the continuous recording medium;
a correction unit that corrects a print position of an image on the continuous recording medium according to a correction amount according to a value detected by the at least one edge sensor;
an imaging unit that reads the inspection pattern recorded on the continuous recording medium;
and an abnormality detection section that determines whether or not there is an abnormality in the at least one end sensor based on the correction amount and the image of the inspection pattern read by the imaging section.

The second aspect of the present invention is the first aspect of the present invention,
The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If the correction amount is outside a predetermined correctable range, determining that there is an abnormality in the at least one end sensor,
When the correction amount is within the correctable range, it is determined whether or not there is an abnormality in the at least one end sensor based on the image of the inspection pattern read by the imaging unit.

The third aspect of the present invention is the first aspect of the present invention,
The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection unit determines whether or not there is an abnormality in the at least one end sensor based on a temporal change in the correction amount and an image of the inspection pattern.

The fourth aspect of the present invention is the first aspect of the present invention,
The at least one recording head is composed of a plurality of recording heads arranged in the conveyance direction of the continuous recording medium, and the plurality of recording heads are configured to eject inks of different colors, respectively,
The at least one edge sensor includes a plurality of edge sensors each corresponding to the plurality of recording heads, and each of the plurality of edge sensors is configured to detect the continuous recording at the position of the corresponding recording head in the transport direction. configured to detect the side edge position of the medium;
The correction unit corrects the print position of the image on the continuous recording medium according to a plurality of correction amounts each corresponding to a value detected by the plurality of edge sensors,
The abnormality detection unit determines whether or not there is an abnormality in the plurality of end sensors based on the plurality of correction amounts and the image of the inspection pattern read by the imaging unit.

The fifth aspect of the present invention is the fourth aspect of the present invention,
The recording control unit is configured to eject ink from the plurality of recording heads at predetermined intervals from each other in the width direction, so that the plurality of linear patterns extending in the transport direction serve as the inspection patterns. controlling the recording unit and the transport mechanism so as to record on the continuous recording medium;
The abnormality detection unit determines the intervals between the plurality of linear patterns indicated by the image of the inspection pattern read by the imaging unit as an inter-pattern distance, and determines the interval between the plurality of linear patterns based on the plurality of correction amounts and the inter-pattern distance. Determine whether there is an abnormality in the end sensor.

The sixth aspect of the present invention is the fifth aspect of the present invention,
The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If any of the plurality of correction amounts is outside a predetermined correctable range, determining that there is an abnormality in one of the plurality of end sensors,
If all of the plurality of correction amounts are within the correctable range, it is determined whether or not there is an abnormality in the plurality of end sensors based on the inter-pattern distance.

A seventh aspect of the present invention is, in the sixth aspect of the present invention,
The abnormality detection section includes:
If all of the plurality of correction amounts are within the correctable range, but any of the inter-pattern distances is outside a predetermined tolerance range, any of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the plurality of correction amounts are within the correctable range and all of the inter-pattern distances are within the allowable range, it is determined that there is no abnormality in the plurality of edge sensors. do.

An eighth aspect of the present invention is, in the fifth aspect of the present invention,
The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If any of the distances between the patterns is out of a predetermined tolerance range, determining that there is an abnormality in any of the plurality of edge sensors,
If all of the inter-pattern distances are within the allowable range, it is determined whether there is an abnormality in the plurality of end sensors based on the plurality of correction amounts.

A ninth aspect of the present invention is, in the eighth aspect of the present invention,
The abnormality detection section includes:
If any of the inter-pattern distances is within the allowable range, but any of the plurality of correction amounts is out of a predetermined correctable range, any one of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the inter-pattern distances are within the allowable range and all of the plurality of correction amounts are within the correctable range, it is determined that there is no abnormality in the plurality of edge sensors. do.

A tenth aspect of the present invention is the first, fourth, or fifth aspect of the present invention,
The recording control section controls the recording section and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium without the printing position being corrected by the correction section.

An eleventh aspect of the present invention is a transport mechanism that transports a long continuous recording medium unwound from a roll-shaped recording medium, and at least one recording head, and the continuous recording from the at least one recording head. a recording unit that records an image by ejecting ink onto a medium; at least one edge sensor that detects a side edge position of the continuous recording medium; and a correction amount according to a detected value by the at least one edge sensor. Therefore, in an inkjet printing apparatus including a correction unit that corrects a printing position of an image on the continuous recording medium, an abnormality detection method for detecting an abnormality in the at least one edge sensor, comprising:
a recording step of recording an inspection pattern on the continuous recording medium together with an image to be printed by the recording unit for detecting a deviation of a printing position on the continuous recording medium in the width direction of the continuous recording medium;
an imaging step of reading the inspection pattern recorded on the continuous recording medium;
and an abnormality detection step of determining whether or not there is an abnormality in the at least one end sensor based on the correction amount and the image of the read inspection pattern.

The twelfth aspect of the present invention is the eleventh aspect of the present invention,
The at least one recording head is composed of a plurality of recording heads arranged in the conveyance direction of the continuous recording medium, and the plurality of recording heads are configured to eject inks of different colors, respectively,
The at least one edge sensor includes a plurality of edge sensors each corresponding to the plurality of recording heads, and each of the plurality of edge sensors is configured to detect the continuous recording at the position of the corresponding recording head in the transport direction. configured to detect the side edge position of the medium;
The correction unit corrects the print position of the image on the continuous recording medium according to a plurality of correction amounts each corresponding to a value detected by the plurality of edge sensors,
In the recording step, a plurality of linear patterns extending in the transport direction are formed as the inspection patterns by ejecting ink from the plurality of recording heads at predetermined intervals from each other in the width direction. recorded on a continuous recording medium,
In the abnormality detection step, an interval between the plurality of linear patterns indicated by the image of the read inspection pattern is determined as an inter-pattern distance, and the distance between the plurality of edge sensors is determined based on the plurality of correction amounts and the inter-pattern distance. The presence or absence of an abnormality in is determined.

Other aspects of the present invention will be clear from the above aspects of the present invention as well as the description of the embodiments and modifications thereof, which will be described later, so their description will be omitted.

In a first aspect of the present invention, the side edge position of a continuous recording medium on which an image to be printed is recorded by ejection of ink from at least one recording head in a recording unit is detected by at least one edge sensor; The printing position of the image on the continuous recording medium is corrected according to the correction amount according to the value detected by at least one edge sensor. As a result, even if the continuous recording medium is meandering, the meandering can be compensated for by correcting the printing position, thereby eliminating misregistration caused by the meandering of the continuous recording medium when printing with an inkjet printing device, and color correction when printing color images. Although the deviation is suppressed, if there is an abnormality in the edge sensor, the print position of the image cannot be corrected to compensate for the meandering of the continuous recording medium. Therefore, an inspection pattern for detecting the deviation of the print position in the width direction of the continuous recording medium on the continuous recording medium is recorded on the continuous recording medium together with the image to be printed, and the correction amount and the inspection pattern according to the detected value are recorded on the continuous recording medium together with the image to be printed. Based on the image, it is determined whether there is an abnormality in the end sensor. As a result, it is possible to detect an abnormality of the end sensor that cannot be detected only by the detection value (or the correction amount corresponding thereto) by the end sensor based on the inspection pattern image. Therefore, according to the first aspect of the present invention, it is possible to more reliably detect an abnormality in an edge sensor used to suppress misregistration and color misregistration due to meandering of paper than in the past.

According to the second aspect of the present invention, if the amount of correction according to the value detected by the end sensor is outside a predetermined correctable range, it is determined that there is an abnormality in the end sensor. Even if the correction amount is within the correctable range, the presence or absence of an abnormality in the end sensor is determined based on the image of the inspection pattern. This provides the same effect as the first aspect of the invention.

According to the third aspect of the present invention, the presence or absence of an abnormality in the edge sensor is determined based on the temporal change in the correction amount according to the detected value by the edge sensor and the image of the inspection pattern. The same effect as in the first aspect can be obtained.

In a fourth aspect of the present invention, the recording section includes a plurality of recording heads arranged in the conveyance direction of the continuous recording medium, and the plurality of recording heads are configured to eject ink of different colors from each other. A plurality of edge sensors are provided respectively corresponding to the plurality of recording heads, and each of the plurality of edge sensors is arranged on the side of the continuous recording medium at the position of the corresponding recording head in the transport direction. It is configured to detect the edge position, and the printing position of the image on the continuous recording medium is corrected according to a plurality of correction amounts corresponding to the detection values by the plurality of edge sensors. According to the fourth aspect of the present invention, in such a configuration, the presence or absence of an abnormality in the plurality of end sensors is determined based on the plurality of correction amounts and the image of the inspection pattern read by the imaging section. , thereby obtaining the same effect as the first aspect of the present invention.

According to the fifth aspect of the present invention, by ejecting ink from a plurality of printheads that eject ink of different colors from each other at predetermined intervals in the width direction of a continuous print medium, continuous printing is possible. A plurality of linear patterns extending in the conveying direction of the recording medium are recorded on the continuous recording medium as inspection patterns. In addition, the intervals between the plurality of linear patterns indicated by the image of the inspection pattern read from the continuous recording medium by the imaging unit are determined as inter-pattern distances, and a plurality of correction amounts are calculated according to the detection values by the plurality of edge sensors. The presence or absence of an abnormality in the plurality of end sensors is determined based on the distance between the patterns. This provides the same effect as the first aspect of the invention.

According to the sixth aspect of the present invention, the inspection pattern is recorded on the continuous recording medium with the print position corrected by the correction section, and a plurality of correction amounts are determined in accordance with detection values by the plurality of edge sensors. If any of the plurality of end sensors is out of the predetermined correctable range, not only is it determined that there is an abnormality in one of the plurality of end sensors, but also all of the plurality of correction amounts are within the correctable range. Even if it is within the range, the presence or absence of an abnormality in the plurality of edge sensors is determined based on the inter-pattern distance in the inspection pattern image read from the continuous recording medium. This provides the same effect as the first aspect of the invention. In addition, since the inspection pattern image consists of multiple linear patterns of different colors and is recorded on the continuous recording medium with the printing position corrected by the correction section, all of the multiple correction amounts are When the correction is within the correctable range, it is possible to easily visually recognize the presence or absence of an abnormality in the plurality of end sensors.

According to the seventh aspect of the present invention, when any one of the plurality of correction amounts corresponding to the detection values by the plurality of end sensors is out of a predetermined correctable range, the plurality of end portions It is determined that one of the sensors has an abnormality, and all of the multiple correction amounts are within the correctable range, but one of the inter-pattern distances in the inspection pattern image read from the continuous recording medium is predetermined. If the error is outside the allowable range, it is determined that there is a possibility of an abnormality in one of the plurality of edge sensors, and all of the plurality of correction amounts are within the correctable range, and , when all of these inter-pattern distances are within the allowable range, it is determined that there is no abnormality in the plurality of end sensors. This provides the same effect as the sixth aspect of the present invention. In addition, since it is possible to determine that there is a possibility of an abnormality with respect to the plurality of end sensors without conclusively stating that there is an abnormality, it is possible to make an alternative judgment as to whether or not there is an abnormality. Compared to the case where continuous recording media meander, problems such as color shift due to meandering can be dealt with more flexibly.

According to the eighth aspect of the present invention, the test pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit, and the distance between patterns in the test pattern image read from the continuous recording medium is determined by the correction unit. Not only is it determined that there is an abnormality in one of the plurality of edge sensors when the distance is outside the allowable range, but even if all of the distances between the patterns are within the allowable range, The presence or absence of an abnormality in the plurality of end sensors is determined based on a plurality of correction amounts corresponding to the values detected by the plurality of end sensors. This provides the same effect as the first aspect of the invention. In addition, since the inspection pattern image consists of multiple linear patterns with different colors and is recorded on a continuous recording medium with the printing position corrected by the correction unit, it is possible to detect abnormalities in the plurality of edge sensors. The presence or absence can be easily recognized visually.

According to the ninth aspect of the present invention, if any of the inter-pattern distances in the inspection pattern image read from the continuous recording medium is out of the allowable range, there is an abnormality in one of the plurality of edge sensors. If it is determined that all of the distances between the patterns are within the allowable range, but one of the multiple correction amounts corresponding to the values detected by the multiple edge sensors is outside the correctable range. It is determined that there is a possibility that there is an abnormality in one of the plurality of edge sensors, all of the distances between the patterns are within the allowable range, and all of the plurality of correction amounts are corrected. If it is within the possible range, it is determined that there is no abnormality in the plurality of end sensors. This provides the same effect as the seventh aspect of the present invention.

According to the tenth aspect of the present invention, since the inspection pattern is recorded on the continuous recording medium without the printing position being corrected by the correction unit, meandering of the continuous recording medium is only detected by the edge sensor. It is also reflected in the inspection pattern image read from the continuous recording medium. Also in the tenth aspect of the present invention, the presence or absence of an abnormality in the edge sensor is determined based on the inspection pattern image and the correction amount according to the detected value by the edge sensor, thereby achieving the first aspect of the present invention. You can get the same effect as the situation.

According to the eleventh aspect of the present invention, the same effects as the first aspect of the present invention can be obtained.

According to the twelfth aspect of the present invention, the same effects as the fifth aspect of the present invention can be obtained.

Since the effects of other aspects of the present invention are clear from the description of the effects of the above aspects of the present invention and the effects of the following embodiments and modifications thereof, their explanations will be omitted.

1 is a schematic diagram showing the configuration of an inkjet printing apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the hardware configuration of a control unit in the first embodiment. FIG. 3 is a plan view for explaining the configuration of a recording section including an edge sensor in the first embodiment. FIG. 3 is a side view showing the configuration of an end sensor in the first embodiment. FIG. 3 is a diagram for explaining the arrangement position of the JI pattern in the first embodiment. FIG. 3 is a diagram for explaining the configuration of a JI pattern in the first embodiment. FIG. 3 is a diagram for explaining sensor abnormality due to adhesion of dust such as paper powder. It is a figure which shows the JI pattern image when the distance between JI patterns shows an abnormal value. 3 is a flowchart showing print control processing in the first embodiment. It is a flowchart which shows the sensor abnormality detection process in the said 1st Embodiment. It is a flow chart which shows sensor abnormality detection processing in a 2nd embodiment of the present invention. It is a flowchart which shows print control processing in a 1st modification. It is a flowchart which shows sensor abnormality detection processing in a 2nd modification. It is a flowchart which shows sensor abnormality detection processing in a 3rd modification. It is a flowchart which shows sensor abnormality detection processing in a 4th modification.

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

<1. First embodiment>
<1.1 Overall configuration>
FIG. 1 is a schematic diagram showing the configuration of an inkjet printing apparatus 10 according to a first embodiment of the present invention. This printing device 10 includes a paper feeding section 202 that unwinds and supplies recording paper (hereinafter also simply referred to as "paper") 5 as a long continuous recording medium from a web of paper as a roll-shaped recording medium; 5 into the printing mechanism 200; a plurality of support rollers 204 which transport the paper 5 inside the printing mechanism 200; A recording unit 205 that performs printing, a drying unit 206 that dries the paper 5 after printing, a second driving roller 207 that outputs the paper 5 from inside the printing mechanism 200, and a winding up of the paper 5 after printing. The paper winding section 208 is also provided. The first drive roller 203, the support roller 204, and the second drive roller 207 constitute a conveyance mechanism for moving the paper 5. The recording unit 205 has first to fourth recordings that eject K (Black), C (Cyan), M (Magenta), and Y (Yellow) inks, respectively. Head rows 205k, 205c, 205m, and 205y are included. Furthermore, the printing mechanism 200 includes an imaging unit 209 configured using an image sensor such as a CCD or CMOS. The imaging unit 209 captures an image of the printed paper 5, and the data obtained by the imaging is sent to the control unit 100.

<1.2 Configuration of control section>
FIG. 2 is a block diagram showing the hardware configuration of the control section 100 in the inkjet printing apparatus 10. The control section 100 includes a main body 11, an auxiliary storage device 12, a display section 14, and an operation section 15. The main body 11 includes a CPU 111, a memory 112, a disk interface section 113, a display control section 115, an input interface section 116, an image processing section 117, a print execution control section 118, an imaging control section 119, and a network interface section 120. . The CPU 111, memory 112, disk interface section 113, display control section 115, input interface section 116, image processing section 117, print execution control section 118, imaging control section 119, and network interface section 120 are interconnected via the system bus. It is connected. The auxiliary storage device 12 is connected to the disk interface section 113. The display unit 14 is connected to the display control unit 115 . The input interface section 116 is connected to the operation section 15 including a keyboard, a mouse, and the like. A network 3 is connected to the network interface unit 120, and the control unit 100 is connected to a host device or the like via this network 3. The auxiliary storage device 12 is a magnetic disk device or the like. The display unit 14 is a liquid crystal display or the like. The display unit 14 is used to display information desired by the operator. The operation unit 15 is used by an operator to input instructions to the inkjet printing apparatus 10.

The auxiliary storage device 12 stores a print control program 17 for generating print data from input data received via the network 3 and causing the printing mechanism 200 to print an image represented by the print data. As will be described later, the printing mechanism 200 includes first to fourth edge sensors 25k that detect the side edge positions of the paper 5 as a long continuous paper (more generally, a continuous recording medium) to be conveyed. 25c, 25m, and 25y are provided, and a sensor abnormality detection program 18 for detecting abnormality in these end sensors 25k, 25c, 25m, and 25y is also stored in the auxiliary storage device 12. The CPU 111 realizes various functions of the inkjet printing apparatus 10 by reading the print control program 17 and the sensor abnormality detection program 18 stored in the auxiliary storage device 12 into the memory 112 and executing them. Memory 112 includes RAM (Random Access Memory) and ROM (Read Only Memory). The memory 112 functions as a work area for the CPU 111 to execute the programs 17 and 18 described above.

Under the control of the CPU 111 that executes the print control program 17, the image processing unit 117 generates print data in bitmap format by performing rasterization processing on submitted data written in a page description language. The print execution control unit 118 functions as an interface for the CPU 111, which executes the print control program, to control each unit of the printing mechanism 200. The imaging control unit 119 functions as an interface for the CPU 111 that executes the print control program to control the imaging unit 209 that captures the image recorded on the paper 5 by the recording unit 205.

<1.3 Configuration of recording section>
FIG. 3 is a plan view for explaining the configuration of the recording unit 205 in this embodiment. As shown in FIGS. 1 and 3, the recording unit 205 stores K (black), C (cyan), M (magenta), and Y (yellow) colors arranged in the conveying direction of the paper 5. It is composed of print head rows (inkjet head rows) 205k, 205c, 205m, and 205y. Each recording head row 205x (x=k, c, m, y) is composed of a plurality of recording heads 21 arranged in two rows in a staggered manner, and is arranged in the paper width direction perpendicular to the conveyance direction of the paper 5. It is extending. These plural recording heads 21 are arranged over the entire width of the paper 5.

As shown in FIG. 3, each recording head 21 includes a large number of nozzles (ink ejection units) 20 arranged in the paper width direction. Each nozzle 20 of each print head 21 in the K color print head row 205k discharges K color ink, each nozzle 20 of each print head 21 in the C color print head row 205c discharges C color ink, Each nozzle 20 of each print head 21 in the M color print head row 205m discharges M color ink, and each nozzle 20 of each print head 21 in the Y color print head row 205y discharges Y color ink.

As shown in FIGS. 1 and 3, end sensors 25k, 25c, 25m, and 25y are provided corresponding to the recording head rows 205k, 205c, 205m, and 205y, respectively. Each edge sensor 25x (x=k, c, m, y) is conveyed relative to the corresponding recording head row 205x so as to be able to detect the side edge position of the paper 5 at the position in the conveying direction of the corresponding recording head row 205x. are arranged closely in the direction. In the following, when referring to one end sensor without distinguishing among the end sensors 25k, 25c, 25m, and 25y, this will be indicated by the symbol "25".

FIG. 4 is a side view showing the configuration of the end sensor 25 in this embodiment. As shown in FIG. 4, the edge sensor 25 includes a light emitting element 251 and a light receiving element 252 facing each other with a gap therebetween, and is arranged so that one end of the paper 5 being conveyed passes through the gap. ing. The light emitting element 251 emits light toward the light receiving element 252 over a range of length Le in the width direction of the paper (hereinafter, the range of length Le in the width direction of the paper is referred to as the "emission range", and is denoted by the same symbol "Le"). ). The light receiving element 252 receives the light emitted from the light emitting element 251 that is not blocked by the edge of the paper 5, and outputs a signal having a value corresponding to the amount of received light. Therefore, the value of the output signal of the edge sensor 25 corresponds to the detected value (detection result) of the side edge position of the paper 5. Note that the configuration of the edge sensor 25 in this embodiment is not limited to the configuration shown in FIG. 4, and may be one that can detect the side edge position of the paper 5 being conveyed and output a signal indicating the side edge position. Other configurations may also be used.

<1.4 JI pattern configuration>
In the inkjet printing apparatus 10 according to the present embodiment, ink is ejected from each recording head array 205x (x=k, c, m, y) to the paper 5 conveyed within the printing mechanism 200, so that the paper is An image to be printed represented by the data (hereinafter referred to as "target image") is recorded on the paper 5. At this time, in addition to the target image, an image for monitoring and controlling the printing operation (hereinafter referred to as "inspection control image") is also printed on the paper 5.

FIG. 5 is a diagram for explaining the arrangement position of a JI (Jet Inspection) pattern for monitoring color misregistration in printing, and FIG. 6 is a diagram for explaining the configuration of the JI pattern. In this embodiment, printing is performed page by page on paper 5 as a continuous paper conveyed within the printing mechanism 200, and as shown in FIG. It is printed close to the start position mark 301. As shown in FIG. 6, the JI pattern image 302 includes a linear pattern 32k to be printed with K color ink ejected from the first print head row 205k, and a C color ink ejected from the second print head row 205c. A linear pattern 32c to be recorded with M color ink ejected from the third print head row 205m, and a linear pattern 32m to be recorded with Y color ink ejected from the fourth print head row 205y. It is composed of a linear pattern 32y to be formed. These four linear patterns 32k, 32c, 32m, and 32y eject ink from the first to fourth recording head rows 205k, 205c, 205m, and 205y at predetermined intervals in the paper width direction, respectively. This is recorded on the paper 5 as a JI pattern image 302. In the JI pattern image 302 recorded on the paper 5 by printing without color shift, these four linear patterns 32k, 32c, 32m, and 32y extend in the transport direction and are arranged at equal intervals in the paper width direction.

<1.5 Detection of abnormality in end sensor>
As described above, in the inkjet printing apparatus 10, in order to suppress color shift etc. caused by the continuous paper 5 being conveyed in a meandering manner, an edge sensor is provided to detect the position of the side edge of the paper. A configuration that moves the recording head in the paper width direction based on the detection result (hereinafter referred to as a "recording head movement configuration") and modification of image data representing the printing target to change the position of the image to be printed based on the detection result. A configuration (hereinafter referred to as an "image data modification configuration") that does this is conventionally known. The inkjet printing apparatus 10 according to the present embodiment also uses detection values (hereinafter also referred to as "sensor detection values") SEk, SEc, SEm, and SEy obtained by the first to fourth end sensors 25k, 25c, 25m, and 25y, respectively. The printer is equipped with either a recording head moving configuration or an image data correcting configuration in order to prevent color misregistration, etc., and an edge sensor is provided so that meandering of the paper 5 is compensated for by the recording head moving configuration or image data correcting configuration. Based on the detection result of 25x, the positions of the target image and the inspection control image (hereinafter referred to collectively as "printed image") are shifted in the paper width direction (x=k, c, m, y). The details of these configurations in this embodiment are the same as those in the prior art and are well known, so their explanation will be omitted. In the following, we will discuss an abnormality (hereinafter referred to as "sensor abnormality") in which the edge sensor 25, which is used in this embodiment to prevent color shift due to meandering of the paper 5, cannot correctly detect the position of the side edge of the paper 5. explain. In the following, for convenience of explanation, it is assumed that the position of the printed image is shifted in the paper width direction based on the detection result of the edge sensor 25 by the image data correction configuration.

As can be seen from the configuration of the edge sensor 25 shown in FIG. 4, when the side edge 5se of the portion of the paper 5 that passes through the gap between the light emitting element 251 and the light receiving element 252 in the edge sensor 25 is within the light emitting range Le. , the end sensor 25 outputs a signal indicating the position of the side end 5se (hereinafter referred to as "side end position") as a detected value. However, if the side edge 5se is outside the light emitting range Le, the detection value output from the edge sensor 25 at that time does not indicate the side edge position of the paper 5, but rather indicates the position of both ends of the light emitting range Le. It will indicate either. Therefore, in this embodiment, a range of detected values corresponding to a predetermined range excluding both ends of the light emitting range Le is set in advance as the detectable range Rd. When the detected value output from the end sensor 25 is within the detectable range Rd, it can be basically considered that the end sensor 25 is operating normally. As described later, in this embodiment, the amount of shift in the position of the print image in the paper width direction (hereinafter referred to as "image position correction amount" or simply "correction amount") is calculated based on the detected value by the edge sensor 25, and printing is performed. During execution, the position of the printed image is shifted at predetermined time intervals according to the correction amount according to the detected value (this shift in the position of the printed image compensates for meandering of the paper (color misalignment due to meandering, etc.) (hereinafter also referred to as "correction for meandering compensation"). However, when the detected value of the edge sensor 25 is outside the detectable range Rd, the image position correction amount calculated based on the detected value of the edge sensor 25 is outside the correctable range.

Therefore, in the present embodiment, a correctable range Rc corresponding to the detectable range Rd is set in advance, and whether or not the correction amount calculated based on the detected value by the end sensor 25 is outside the correctable range Rc is determined in advance. Accordingly (x=k, c, m, y), it is determined whether or not the sensor is abnormal (details will be described later).

In addition, if dust such as paper powder is attached to the end sensor 25, the light emitted from the light emitting element 251 and to be received by the light receiving element 252 is blocked by the dust, so that the end sensor 25 can detect the dust. The value may be different from the value indicating the side edge position of the paper 5. Further, in this case, even if the side edge 5se of the paper 5 is outside the light emitting range Le, the detection value output from the edge sensor 25 may be within the detectable range Rd.

FIG. 7 is a diagram for explaining such a sensor abnormality caused by adhesion of dust such as paper dust. FIG. 7 shows temporal changes in the detected value SEc by the edge sensor 25c disposed close to the second print head row 205c that ejects C color (cyan) ink. In FIG. 7, the numerical values attached to the horizontal axis indicate each detection time of the edge sensor 25c that detects the side edge position at predetermined time intervals, using the time interval as a unit. In this example, the paper 5 is conveyed in a meandering manner within the printing mechanism 200, and the detected value by the edge sensor 25c is expected to change as shown by the dotted line in FIG. However, as shown in FIG. 7, paper dust adheres to the end sensor 25c after time 3 and before time 4, so that the detected value remains constant after time 12 and does not change. Therefore, after this time 12 has elapsed, the end sensor 25c is in a state where an abnormality has occurred.

As mentioned above, an abnormality (sensor abnormality) that occurs in the end sensor 25 due to the adhesion of dust such as paper powder is determined by whether the detected value is outside the detectable range Rd (if the correction amount is outside the correctable range Rc). It cannot be detected by simply checking whether there is a However, such a sensor abnormality can be detected based on the previously described JI pattern image 302 (FIGS. 5 and 6) recorded on each page of the paper 5. Detection of a sensor abnormality using the JI pattern image 302 of such a sensor abnormality will be described below.

Regardless of whether a sensor abnormality occurs because the side edge 5se of the paper is outside the light emitting range Le or when a sensor abnormality occurs due to dust such as paper dust adhering to the edge sensor 25, the edge Since the detected value by the sensor 25 does not indicate the position of the side edge of the paper 5, correction for meandering compensation cannot be performed correctly. In other words, it is not possible to correctly shift the image position to prevent color shift and the like. Therefore, as shown in FIG. 3, linear patterns 32k, 32c, 32m, and 32y are recorded by the first to fourth recording head rows 205k, 205c, 205m, and 205y, which are arranged at mutually different positions in the transport direction. In the JI pattern image 302, the position of any one of the linear patterns 32k, 32c, 32m, and 32y is shifted from its original position. Here, as shown in FIG. 6, based on the linear pattern 32k (hereinafter referred to as "K color linear pattern") recorded by the first recording head row 205k, the K color linear pattern 32k and the fourth recording head row The distance between the linear pattern 32y (hereinafter referred to as "Y color linear pattern") recorded by 205y (hereinafter referred to as "K-Y pattern distance") is indicated by the symbol "Dy", and the distance between the K color linear pattern 32k and The distance between the linear pattern (hereinafter referred to as "M color linear pattern") 32m recorded by the third recording head row 205m (hereinafter referred to as "K-M pattern distance") is indicated by the symbol "Dm", and the K color The distance between the linear pattern 32k and the linear pattern (hereinafter referred to as "C color linear pattern") 32c recorded by the second recording head row 205c (hereinafter referred to as "KC pattern distance") is denoted by the symbol "Dc". shall be shown as Hereinafter, the K-Y pattern distance Dy, the K-M pattern distance Dm, and the KC pattern distance Dc will be collectively referred to as "JI pattern distance." Note that the distance between the side edge of the paper 5 and the K color linear pattern 32k is indicated by the symbol "Dk".

If there is no sensor abnormality in any of the end sensors 25k, 25c, 25m, 25y (if there is no abnormality in any of the end sensors 25k, 25c, 25m, 25y), that is, the end sensors 25k, 25c, 25m . As shown in FIG. 6, three linear patterns 32k, 32c, 32m, and 32y are lined up at equal intervals within a predetermined tolerance range, as shown in FIG. The inter-pattern distances Dc, Dm, and Dy satisfy the following formulas (1) and (2).
Dc≒(1/3)Dy…(1)
Dm≒(2/3)Dy…(2)

On the other hand, if a sensor abnormality occurs in any of the end sensors 25k, 25c, 25m, or 25y (if any of the end sensors 25k, 25c, 25m, or 25y has an abnormality), the JI pattern The distances Dc, Dm, and Dy do not satisfy at least one of the above formulas (1) and (2). For example, if a sensor abnormality occurs in the second end sensor 25c due to adhesion of paper dust as shown in FIG. ), and the intervals are not equal within a predetermined tolerance range, so the above formula (1) is not satisfied. At this time, the position of the C-colored linear pattern 32c in the JI pattern image 302 is significantly shifted compared to when no sensor abnormality occurs. Therefore, even if there is a sensor abnormality that cannot be detected using only the detection value from the end sensor 25, such as a sensor abnormality caused by adhesion of paper dust, etc., this can be detected by checking the distances Dc, Dm, and Dy between the JI patterns. can do.

In addition, in the following, when the expression "no sensor abnormality has occurred" is used without specifying any of the end sensors 25k, 25c, 25m, 25y, this expression will be replaced by "the end sensors 25k, 25c, 25m, 25y," and the expression "a sensor abnormality has occurred" was used without specifying any of the end sensors 25k, 25c, 25m, and 25y. In this case, this expression means "a sensor abnormality has occurred in one of the end sensors 25k, 25c, 25m, and 25y."

On the other hand, it may not be possible to determine whether a sensor abnormality has occurred (presence or absence of an abnormality in the end sensor) by simply checking the distances Dc, Dm, and Dy between the JI patterns. For example, there is a case where all or part of the linear patterns 32k, 32c, 32m, and 32y cannot be read satisfactorily due to a malfunction in the imaging unit 209. Alternatively, there is a case where all or part of the linear patterns 32k, 32c, 32m, and 32y cannot be printed satisfactorily due to a malfunction in the recording unit 205.

Even if it is not possible to determine whether a sensor abnormality has occurred by simply checking the JI pattern distances Dc, Dm, and Dy as described above, any of the sensor detection values SEk, SEc, SEm, and SEy can be detected. If it is outside the range Rd, that is, if any of the correction amounts (image position correction amounts) CAk, CAc, CAm, CAy corresponding to the sensor detection values SEk, SEc, SEm, SEy is outside the correctable range Rc. For example, it can be determined that a sensor abnormality has occurred.

In addition, even if it appears that there is no abnormality in the distances Dc, Dm, and Dy between JI patterns, there is a possibility of sensor abnormality in cases where the correction amounts CAk, CAc, CAm, and CAy vary over time. It can be determined that there is a sex.

<1.6 Print control processing and sensor abnormality detection processing>
In this embodiment, the control unit 100 is configured so that an operating system (hereinafter abbreviated as "OS") having a process management function operates when the CPU 111 executes a predetermined program. Then, as described later, the print control program 17 and the sensor abnormality detection program 18 are read from the auxiliary storage device 12 to the memory 112 and executed as applications by the CPU 111 using the functions provided by this OS. , print control processing, and sensor abnormality detection processing are two processes that operate in parallel to each other. Note that this OS provides system functions for synchronization, data exchange, and sharing among a plurality of processes running on the CPU 111.

FIG. 9 is a flowchart showing print control processing realized by the CPU 111 executing the print control program 17 in this embodiment. In the inkjet printing apparatus 10 according to the present embodiment, in order to perform printing based on input data, the control unit 100 generates print data according to the procedure shown in FIG. The control section 208 is controlled, etc. (see FIGS. 1 and 2). For this purpose, the CPU 111 first reads the print control program 17 from the auxiliary storage device 12 into the memory 112 and executes it as an application under the management of the OS. As a result, the print control process shown in FIG. 9 is activated as one process, and the CPU 111 operates as described below according to the print control program 17.

First, the image processing unit 117 is controlled to perform rasterization processing on input data provided from the outside via the network 3, thereby generating print data in bitmap format (step S12). The image represented by this print data includes an inspection control image including the JI pattern image 302 in addition to the target image, which is the image to be printed represented by the input data (see FIGS. 5 and 6).

Thereafter, print execution control for printing the image represented by the generated print data is started (step S14). Specifically, in order to record an image represented by print data (a print image consisting of a target image and an inspection control image) on paper 5, in addition to recording section 205, paper feeding section 202, drive rollers 203 and 207, and drying section 206 are used. , the image capturing section 209, and the operation of controlling the paper winding section 208 are started (see FIG. 1). As a result, the target image and the inspection control image are recorded by the recording unit 205 on the paper 5 that is unwound and conveyed from the paper feeding unit 202, and the recorded images are read by the imaging unit 209. The recorded paper 5 is wound up by the paper winding section 208. Furthermore, the side edge positions of the paper 5 being conveyed within the recording unit 205 are detected by edge sensors 25k, 25c, 25m, and 25y. Furthermore, with the start of such print execution control, sensor abnormality detection processing, which will be described later, is started (see FIG. 10). That is, under the management of the OS, the sensor abnormality detection program 18 is read from the auxiliary storage device 12 to the memory 112 and executed as an application. As a result, the sensor abnormality detection process shown in FIG. 10 is activated as a separate process that operates in parallel to the print control process.

When the printing execution control and sensor abnormality detection processing are started in this way, the detection values obtained by the edge sensors 25k, 25c, 25m, and 25y that detect the side edge positions of the paper 5 under the printing execution control, The sensor detection values SEk, SEc, SEm, and SEy are acquired (step S16), and based on these sensor detection values SEk, SEc, SEm, and SEy, a correction amount (image position correction amount) that compensates for the meandering of the paper 5 is determined. ) CAk, CAc, CAm, and CAy are calculated, respectively (step S18). Next, the image position is shifted in the paper width direction according to the calculated correction amounts CAk, CAc, CAm, and CAy (step S22). That is, at a position corresponding to each end sensor 25x in the transport direction, the position of the print image is shifted in the paper width direction according to the correction amount CAx (x=k, c, m, y).

Thereafter, it is determined whether the sensor abnormality detection process started in step S14, which is a process that operates in parallel with the print control process, has ended (step S24).

As a result of the determination in step S24, if the sensor abnormality detection process has not been completed, the process advances to step S26 to determine whether or not the printout of the generated print data has been completed, that is, the printout represented by the print data. It is determined whether recording of the image on the paper 5 has been completed. As a result of the determination, if the printout of the print data has not been completed, the process returns to step S16. Thereafter, unless the sensor abnormality detection process is completed, steps S16 to S26 are repeatedly executed until the printout of the print data is completed.

While steps S16 to S26 are being repeatedly executed, if it is determined in step S24 that the sensor abnormality detection process has been completed, or if it is determined in step S26 that the printout of the print data has been completed, the print Execution control is stopped (step S28). As a result, the recording section 205, paper feeding section 202, drive rollers 203, 207, drying section 206, imaging section 209, and paper winding section 208 stop operating, and printing of the print data is completed. Furthermore, if the sensor abnormality detection process is continuing at this point (the sensor abnormality detection process is in operation), the sensor abnormality detection process is stopped.

Next, post-processing is executed according to the sensor information set in the sensor abnormality detection process (step S29), and then the print control process is ended. Details of this sensor information and post-processing will be described later.

FIG. 10 is a flowchart showing sensor abnormality detection processing realized by the CPU 111 executing the sensor abnormality detection program 18. When this sensor abnormality detection process is started as described above as a separate process that operates in parallel with the print control process, the CPU 111 operates as described below according to the sensor abnormality detection program 18.

First, the JI pattern image 302 is acquired from among the print images read from the paper 5 by the imaging unit 209 under print execution control started in the print control process (step S102) (see FIGS. 5 and 6). Next, distances Dc, Dm, and Dy between JI patterns are calculated from the acquired JI pattern image 302 (step S104) (see FIGS. 6 and 8).

Next, in the print control process, correction amounts (image position correction amounts) CAk, CAc, CAm, and CAy calculated from the sensor detection values SEk, SEc, SEm, and SEy are obtained (step S106). That is, when the correction amounts CAk, CAc, CAm, and CAy are calculated in the print control process (step S18 in FIG. 9), these are shared by the sensor abnormality detection process and the print control process in the memory 112. In step S106, the correction amounts CAk, CAc, CAm, and CAy are acquired from this shared memory. However, the correction amounts CAk, CAc, CAm, CAy obtained here are the correction amounts CAk, CAc calculated from the sensor detection values SEk, SEc, SEm, SEy obtained at relatively short predetermined time intervals in the print control process. , CAm, CAy (see FIG. 7), the correction is calculated from the sensor detection values SEk, SEc, SEm, SEy obtained at the time when the printed image including the JI pattern image 302 is read or at the time closest thereto. The quantities CAk, CAc, CAm, and CAy.

Thereafter, it is determined whether any of the acquired correction amounts CAk, CAc, CAm, and CAy is outside the correctable range Rc (step S108). As a result of this determination, if any of these correction amounts CAk, CAc, CAm, CAy is outside the correctable range Rc, the correction amount CAx (x is k, c, The identification information ID of the end sensor 25x corresponding to either of m or y) and the status value ST2 indicating sensor abnormality are set as sensor information (step S116), and the sensor abnormality detection process is ended.

On the other hand, if it is determined in step S108 that none of the correction amounts CAk, CAc, CAm, and CAy are outside the correctable range Rc, the process advances to step S110, and the distance between the JI patterns calculated in step S104 is It is determined whether any of Dc, Dm, and Dy is outside the allowable range. As a result of this determination, if all of the JI pattern distances Dc, Dm, and Dy are within the allowable range, the process advances to step S118.

In step S118, the possibility of sensor abnormality is examined in consideration of the presence or absence of an abnormality in the temporal change of the correction amounts CAk, CAc, CAm, and CAy, and the mutual comparison between the correction amounts CAk, CAc, CAm, and CAy. As mentioned earlier, when paper powder adheres to the end sensor 25, the correction amounts CAk, CAc, CAm, and CAy are within the correctable range Rc, so it is impossible to determine whether the end sensor 25 is abnormal. It's not easy. However, at the stage of step S118, since it has been confirmed in the previous step S110 that the distance between the JI patterns does not fall outside the allowable range, the meandering correction based on the output of the end sensor 25 is performed normally. It is possible to infer that. Therefore, the end sensor 25 that behaves even slightly abnormally in step S118 can be considered to have a high probability of being abnormal. Therefore, in step S118, the correction amounts CAk, CAc, CAm, and CAy are checked for a predetermined period of time, and an unnatural fluctuation is found in any of the correction amounts CAx (x is one of k, c, m, and y). If so, it is determined that there is an abnormality in the correction amount CAx, and the process proceeds to step S120. In step S120, the identification information ID of the corresponding end sensor 25x and the status value ST1 indicating the possibility of sensor abnormality are set as sensor information, and the sensor abnormality detection process is ended. The unnatural fluctuation in the correction amount CAx includes an example in which the fluctuation in the correction amount CAx within a predetermined period of time is unnaturally large/small. Further, as shown in FIG. 3, the printing mechanism 200 in this embodiment includes a plurality of edge sensors 25k, 25c, 25m, and 25y, so some of the edge sensors 25x (x is k, c, m, y) is unnaturally different from the correction amount CAz of the other end sensor 25z (z is any one of k, c, m, y, and z≠x). It is also possible to determine that there is an abnormality in the correction amount CAx of the part of the end sensor 25x.

If it is determined in step S118 that there is no abnormality in the correction amounts CAk, CAc, CAm, CAy, the process proceeds to step S122, where the status value ST0 indicating sensor normality is set as sensor information, and the process returns to step S102.

At the time of execution of step S118 described above, the image 302 of the JI pattern has been recorded on the paper 5 with the print position corrected in step S22 before that. Then, the control unit 100 as an abnormality detection unit determines whether the determination result in S110 (whether or not the distance between JI patterns is outside the allowable range) and the determination result in S118 (which of the correction amounts CAk, CAc, CAm, CAy) It is determined whether the end sensor 25 is normal (step S122) or there is a possibility of an abnormality (steps S120, S112). It's coming down.

While steps S102 to S110, S118, and S122 are repeatedly executed, if it is determined in step S108 that any of the correction amounts CAk, CAc, CAm, and CAy is outside the correctable range Rc, the sensor It is determined that an abnormality has occurred (it is determined that there is an abnormality in any of the end sensors 25k, 25c, 25m, 25y), and the correction amount CAx (x is k, c, m , y) and the status value ST2 indicating sensor abnormality are set as sensor information (step S116), and the sensor abnormality detection process is ended.

Further, while repeatedly executing steps S102 to S110, S118, and S122, if it is determined in step S110 that any of the JI pattern distances Dc, Dm, and Dy is out of the allowable range, Considering that all of the correction amounts CAk, CAc, CAm, and CAy were determined to be within the correctable range Rc in the immediately preceding step S108, it is not determined that the sensor is abnormal, but that a sensor abnormality has occurred. It is determined that there is a possibility, and the identification information ID of the end sensor 25x corresponding to the JI pattern distance Dx (x is one of c, m, or y) that is out of the allowable range and the possibility of sensor abnormality are shown. The state value ST1 is set as sensor information (step S112), and the sensor abnormality detection process is ended.

In addition, if it is determined in step S118 that any of the correction amounts CAk, CAc, CAm, CAy is abnormal while steps S102 to S110, S118, and S122 are repeatedly executed, the step immediately before that Considering that the distances Dc, Dm, and Dy between the JI patterns calculated in S110 are all determined to be within the allowable range, it is not determined that there is a sensor abnormality, but there is a possibility that a sensor abnormality has occurred. The identification information ID of the end sensor 25x corresponding to the correction amount CAx (x is one of k, c, m, or y) that is determined to be abnormal and the state indicating the possibility of sensor abnormality. The value ST1 is set as sensor information (step S120), and the sensor abnormality detection process is ended.

It is assumed that the sensor information set in steps S112, S116, S120, and S122 is stored in an area of the memory 112 that is shared by the sensor abnormality detection process and the print control process, that is, a shared memory. (See step S29 in FIG. 9) (This also applies to other embodiments and modifications described later). Therefore, the post-processing in step S29 in the print control process is performed using the sensor information set by the sensor abnormality detection process.

As the post-processing (step S29 in FIG. 9) executed in the print control process, the following process may be performed. However, in this embodiment, the process is not limited to these processes, and even if the process is different from these processes or includes other processes in addition to these processes, the state values ST0 to ST0 included in the sensor information Appropriate processing according to ST2 may be performed.
(1) When the sensor information includes a status value ST2 indicating a sensor abnormality, the end sensor 25x specified by the identification information ID included in the sensor information is not used, but is placed before and after the end sensor 25x. The detected value of the edge sensor 25x is predicted by interpolation or the like from the detected value of the edge sensor 25x. In the subsequent print control process, the predicted values are used instead of the values detected by the edge sensor 25x to calculate the correction amounts CAk, CAc, CAm, and CAy (steps S16 and S18 in FIG. 9).
(2) When the sensor information includes a status value ST1 indicating the possibility of a sensor abnormality, a function is implemented to supplement the user's judgment regarding the sensor abnormality as a warning. For example, warning information indicating that there is a possibility of sensor abnormality in the end sensor 25x specified by the identification information ID included in the sensor information is notified to the user by voice or display.
(3) If the sensor information includes a status value ST2 indicating a sensor abnormality or a status value ST1 indicating the possibility of a sensor abnormality, automatic cleaning or flushing to recover from a chipped nozzle should be performed every predetermined amount of print output. The printing mechanism 200 is controlled accordingly.
(4) If there is an end sensor 25x among the end sensors 25k, 25c, 25m, and 25y in which a sensor abnormality occurs more than a predetermined frequency, identify that end sensor 25x based on sensor information, and Warning information indicating that the sensor 25x may be malfunctioning is notified to the user by voice or display.
(5) If the sensor information includes a status value ST0 indicating that the sensor is normal, post-processing may be omitted, but it indicates that the end sensors 25k, 25c, 25m, and 25y are operating normally. The log information may be accumulated in the control unit 100.

<1.7 Effects>
According to the present embodiment as described above, any one of the correction amounts (image position correction amounts) CAk, CAc, CAm, CAy calculated from the sensor detection values SEk, SEc, SEm, SEy is out of the correctable range Rc. In addition to determining whether the JI pattern distances Dc, Dm, or Dy are outside the allowable range (steps S108 and S110 in FIG. 10), the results of both determinations are Based on this, a sensor abnormality is detected. In the conventional technology, in which a sensor abnormality was detected only based on the detected value by the edge sensor, the edge sensor could not correctly detect the side edge position of the paper due to dust such as paper dust adhering to the edge sensor. Even if the correction for meandering compensation was not performed appropriately, it was not possible to detect that a sensor abnormality had occurred. On the other hand, according to the present embodiment, since the detected value SEx by one of the end sensors 25x (x is one of k, c, m, and y) is within the detectable range Rd, the correction amount CAx is corrected. Although it is within the possible range Rc, if the detected value SEx is not a correct value due to dust such as paper dust adhering to the end sensor 25x, the distance Dx between the JI patterns will be out of the allowable range. , This makes it possible to detect sensor abnormalities. In this way, an abnormality in the edge sensor (sensor abnormality) that detects the position of the side edge of the paper 5 in order to prevent color shift due to meandering of the paper can be detected more reliably than in the past.

Further, according to the present embodiment, when a sensor abnormality occurs, the JI pattern recorded on the paper 5 indicates that at least one of the inter-JI pattern distances Dc, Dm, and Dy is deviated from the normal position. This can be easily confirmed visually by observing the pattern image.

Furthermore, according to the present embodiment, not only is one of two types of sensor information indicating whether or not a sensor abnormality is set, but also when there is a possibility of a sensor abnormality although it cannot be determined that the sensor is abnormal. Sensor information indicating the possibility of such sensor abnormality is set (step S112 in FIG. 10). As a result, problems such as color shift due to meandering of the paper 5 can be dealt with more flexibly than in the case where a binary judgment is made as to whether or not there is a sensor abnormality. Therefore, it is possible to take more appropriate measures according to the sensor information obtained regarding the sensor abnormality.

Furthermore, according to the present embodiment, when sensor abnormality cannot be reliably determined only by determination based on the distance between JI patterns, the image can be imaged by taking into account temporal changes and mutual comparison of sensor correction values CAk, CAc, CAm, CAy. The possibility of any abnormality in the position correction amount CAx is determined (step S118 in FIG. 10). This allows decisions to be made based on more factors, allowing for more flexibility.

<2. Second embodiment>
In the first embodiment, in the sensor abnormality detection process, any one of the correction amounts (image position correction amounts) CAk, CAc, CAm, and CAy calculated from the sensor detection values SEk, SEc, SEm, and SEy is within the correctable range. It is determined whether or not they deviate from Rc, and as a result of the determination, if all of these correction amounts CAk, CAc, CAm, and CAy are within the correctable range Rc, the JI pattern distances Dc, Dm, It is determined whether any of Dy is outside the allowable range (steps S108 and S110 in FIG. 10). However, as shown in FIG. 11, it is not necessary to determine whether any of the correction amounts CAk, CAc, CAm, and CAy is outside the correctable range Rc. FIG. 11 is a flowchart showing sensor abnormality detection processing when such a configuration is adopted. In FIG. 11, the same step numbers are assigned to the same parts of the sensor abnormality detection process as in the sensor abnormality detection process (FIG. 10) in the first embodiment. As can be seen by comparing FIG. 11 with FIG. 10, in the sensor abnormality detection process of FIG. 11, step S108, which constitutes the sensor abnormality detection process in the first embodiment, is deleted. Further, if the determination in step S110 is "Yes", the process immediately moves to step S116 in which sensor information indicating sensor abnormality is set. The other parts are the same as the sensor abnormality detection process in the first embodiment.

<3. Modified example>
<3.1 First modification example>
In the first embodiment, in the sensor abnormality detection process (FIG. 10), the correction amounts (image position correction amounts) CAk, CAc, CAm, CAy and the JI pattern distances Dc, Dm, Based on Dy, it is determined whether the end sensors 25k, 25c, 25m, and 25y are operating normally, but if any of these correction amounts CAk, CAc, CAm, and CAy is out of the correctable range Rc. If so, it is determined that a sensor abnormality has occurred without considering the distances Dc, Dm, and Dy between the JI patterns (steps S108→S116 in FIG. 10). These correction amounts CAk, CAc, CAm, and CAy are calculated from the sensor detection values SEk, SEc, SEm, and SEy in the printing control process (FIG. 9) (steps S16 and S18 in FIG. 9). Therefore, in the print control process, sensor abnormality may be detected based on the correction amounts CAk, CAc, CAm, CAy calculated from the sensor detection values SEk, SEc, SEm, SEy. FIG. 12 is a flowchart showing print control processing when such a configuration is adopted. In FIG. 12, the same step numbers are assigned to the same parts of the print control process as in the print control process (FIG. 9) in the first embodiment. As can be seen by comparing FIG. 12 with FIG. 9, in the print control process of FIG. 12, steps S20 and S25 are added to the print control process of the first embodiment (FIG. 9), and other parts are is the same as the print control process in the first embodiment. In the second embodiment, the print control process shown in FIG. 12 may be used instead of the print control process shown in FIG. 9.

Hereinafter, an inkjet printing apparatus employing the print control process shown in FIG. 12 will be described as a first modification. Note that in this modification, the configuration other than the print control process is the same as that of the first embodiment, so the same or corresponding parts are given the same reference numerals and the explanation will be omitted. However, the sensor abnormality detection process shown in FIG. 10 may be modified to correspond to the print control process shown in FIG. 12. For example, in the flowchart of FIG. 10, if step S116 is deleted and it is determined in step S108 that any of the correction amounts CAk, CAc, CAm, CAy is outside the correctable range Rc, the sensor information settings are changed. The sensor abnormality detection process may be terminated without being performed.

Also in the inkjet printing device according to this modification, in order to perform printing based on input data, the CPU 111 first reads the print control program 17 from the auxiliary storage device 12 to the memory 112 under the management of the OS described above. and run it as an application. As a result, the print control process shown in FIG. 12 is activated as one process, and the CPU 111 operates as follows according to the print control program 17 in this modification, that is, according to the procedure shown in FIG. 12.

First, in steps S12 to S18, in the same manner as in the first embodiment (FIG. 9), print data is generated, print execution control is started, sensor abnormality detection processing is started (sensor abnormality detection processing process is started), Acquisition of sensor detection values SEk, SEc, SEm, SEy, and calculation of correction amounts (image position correction amounts) CAk, CAc, CAm, CAy based on these sensor detection values SEk, SEc, SEm, SEy are performed. Thereafter, unlike the first embodiment, it is determined whether any of the calculated correction amounts CAk, CAc, CAm, CAy is outside the correctable range Rc (step S20). As a result of this determination, if all of these correction amounts CAk, CAc, CAm, and CAy are within the correctable range Rc, the process advances to step S22, and step S22 of the print control process in the first embodiment is performed. Processing similar to ~S29 is performed.

On the other hand, as a result of the determination in step S20, if any of these correction amounts CAk, CAc, CAm, CAy is outside the correctable range Rc, it is determined that a sensor abnormality has occurred, and the correctable range is The identification information ID of the end sensor 25x corresponding to the correction amount CAx (x is one of k, c, m, or y) that deviates from Rc and the status value ST2 indicating sensor abnormality are set as sensor information (step S25) and proceeds to step S28. The subsequent processes (steps S28 and S29) are similar to the print control process in the first embodiment.

In this modification as described above, in order to compensate for the meandering of the paper 5, the correction amounts CAk, CAc, CAm, CAy are calculated based on the sensor detection values SEk, SEc, SEm, SEy acquired at predetermined time intervals. Each time, it is determined whether these correction amounts CAk, CAc, CAm, CAy are outside the correctable range Rc (steps S16 to S20). As a result of this determination, if any of these correction amounts CAk, CAc, CAm, CAy is out of the correctable range Rc, the end sensor 25x corresponding to the correction amount CAx that is out of the correctable range Rc. The identification information ID and the status value ST2 indicating sensor abnormality are set as sensor information, and print execution control and sensor abnormality detection processing are stopped (step S28). Thereafter, the above-mentioned post-processing is executed according to the set sensor information (step S29), and the print control process ends. Therefore, according to this modification, in addition to obtaining the same effects as the first embodiment, it is possible to quickly detect the occurrence of a sensor abnormality and perform post-processing in accordance with the sensor abnormality.

<3.2 Second modification example>
In the first and second embodiments described above, the correction amounts (image position correction amounts) CAk, CAc, CAm, CAy calculated from the sensor detection values SEk, SEc, SEm, SEy and the JI pattern image 302 are Sensor abnormality can be detected more reliably based on the distances Dc, Dm, and Dy between the JI patterns. To detect this sensor abnormality, the sensor abnormality detection process shown in FIG. 10 is used in the first embodiment, and the sensor abnormality detection process shown in FIG. 11 is used in the second embodiment. However, the sensor abnormality detection processing that can be used to detect sensor abnormality is not limited to that shown in FIGS. 10 and 11, and the sensor abnormality detection process is Other sensor abnormality detection processes may be used as long as they can be detected reliably. For example, the sensor abnormality detection process shown in FIG. 13 may be used instead of the sensor abnormality detection process shown in FIGS. 10 and 11.

As can be seen by comparing FIG. 13 with FIG. 10, in the sensor abnormality detection process in FIG. 13, step S115 is added to the sensor abnormality detection process in FIG. 10 (the sensor abnormality detection process in the first embodiment). The other parts are the same as the print control process shown in FIG. In the sensor abnormality detection process shown in FIG. 13, unlike the sensor abnormality detection process shown in FIG. In addition, it is determined whether any of the JI pattern distances Dc, Dm, and Dy is outside the allowable range (step S115). As a result of this determination, if all of the JI pattern distances Dc, Dm, and Dy are within the allowable range, then the correction amount CAx (x is one of k, c, m, and y) that is outside the correctable range Rc. ) and the status value ST1 indicating the possibility of sensor abnormality are set as sensor information (step S114), and the sensor abnormality detection process ends. On the other hand, as a result of the determination in step S115, if any of the JI pattern distances Dc, Dm, Dy is outside the tolerance range, the JI pattern distance Dx (x is k, c , m, y) and the status value ST2 indicating sensor abnormality are set as sensor information (step S116), and the sensor abnormality detection process ends.

In this way, in the sensor abnormality detection process shown in FIG. If both conditions are satisfied, it is determined that a sensor abnormality has occurred (step S116), and if only one of the conditions is satisfied, it is not determined that a sensor abnormality has occurred. It is determined that there is a possibility of sensor abnormality (step S114), and if neither condition is satisfied, it is determined that the sensor is normal (step S112).

Even when the sensor abnormality detection process described above is adopted, abnormalities in the edge sensor that detects the side edge position of the paper 5 (sensor abnormality) can be detected more reliably than before to prevent color misalignment due to meandering of the paper. can be detected, and the same effects as in the first embodiment can be obtained.

<3.3 Third modification example>
The sensor abnormality detection process shown in FIG. 14 may be used instead of the sensor abnormality detection process shown in FIG. 13 in the second modification. Hereinafter, an inkjet printing apparatus that performs sensor abnormality processing shown in FIG. 14 will be described as a third modification. FIG. 14 is a flowchart showing sensor abnormality detection processing in this modification. In FIG. 14, the same step numbers are given to the same parts of the sensor abnormality detection process as in the sensor abnormality detection process in the second modification (FIG. 13).

As can be seen by comparing FIG. 14 with FIG. 13, in the sensor abnormality detection process of FIG. 14, step S115 in the sensor abnormality detection process of FIG. 13 is deleted, and the other parts are the same as the sensor abnormality detection process of FIG. The same is true.

As shown in FIG. 14, in the sensor abnormality detection process in this modification, if it is determined in step S108 that any of the correction amounts CAk, CAc, CAm, CAy is out of the correctable range Rc, the sensor It is determined that an abnormality has occurred, and the process advances to step S116. In step S108, it is determined that all of the correction amounts CAy, CAm, CAc, and CAk are within the correctable range Rc, but in step S110, any of the JI pattern distances Dc, Dm, and Dy is out of the allowable range. If it is determined that the sensor is abnormal, it is determined that there is a possibility that a sensor abnormality has occurred, and the process proceeds to step S114. In step S108, it is determined that all of the correction amounts CAy, CAm, CAc, and CAk are within the correctable range Rc, and in step S110, all of the JI pattern distances Dc, Dm, and Dy are within the allowable range. If it is determined that the sensor is abnormal, it is determined that no sensor abnormality has occurred (the sensor is normal), and the process advances to step S112.

<3.4 Fourth modification example>
The sensor abnormality detection process shown in FIG. 15 may be used instead of the sensor abnormality detection process shown in FIG. 14 in the third modification. Hereinafter, an inkjet printing apparatus that performs sensor abnormality processing shown in FIG. 15 will be described as a fourth modification. FIG. 15 is a flowchart showing sensor abnormality detection processing in this modification. In FIG. 15, the same step numbers are assigned to the same parts of the sensor abnormality detection process as in the sensor abnormality detection process in the third modification (FIG. 14).

As can be seen by comparing FIG. 15 with FIG. 14, in the sensor abnormality detection process in FIG. 15, steps S108 and S110 in the sensor abnormality detection process in the third modification are replaced with steps S109 and S111, respectively. The other parts are the same as the sensor abnormality detection process in the third modification.

As shown in FIG. 15, in the sensor abnormality detection process in this modification, if it is determined in step S109 that any of the JI pattern distances Dc, Dm, Dy is outside the allowable range, the sensor abnormality is detected. It is determined that this has occurred, and the process advances to step S116. Although it is determined in step S109 that all of the JI pattern distances Dc, Dm, and Dy are within the allowable range, in step S111, any of the correction amounts CAy, CAm, CAc, and CAk is out of the correctable range Rc. If it is determined that there is a sensor abnormality, it is determined that there is a possibility that a sensor abnormality has occurred, and the process proceeds to step S114. In step S109, it is determined that all of the JI pattern distances Dc, Dm, and Dy are within the allowable range, and in step S111, all of the correction amounts CAy, CAm, CAc, and CAk are within the correctable range Rc. If it is determined that the sensor is abnormal, it is determined that no sensor abnormality has occurred (the sensor is normal), and the process proceeds to step S112.

<3.5 Other variations>
In the first and second embodiments described above, not only the print position of the target image but also the print position of the JI pattern image 302 is shifted in accordance with the correction of the image position to compensate for meandering of the paper 5 (steps in FIG. 9). As a result, when the edge sensors 25k, 25c, 25m, and 25y correctly detect the side edge position of the paper 5, the JI pattern recorded on the paper 5 even if the paper 5 meanders. The linear patterns 32k, 32c, 32m, and 32y in the image 302 are maintained at their normal positions. However, the linear patterns 32k, 32c, 32m, and 32y in the JI pattern image 302 are recorded on the paper 5 by ejecting ink from specific nozzles 20 in the recording head rows 205k, 205c, 205m, and 205y, respectively. You can also do this. That is, the JI pattern image 302 of the print image may be recorded on the paper 5 by the recording head arrays 205k, 205c, 205m, and 205y without performing correction for meandering compensation (image data correction). . In this way, the positions of the linear patterns 32k, 32c, 32m, and 32y in the JI pattern image 302 recorded on the paper 5 will shift from their normal positions in accordance with the meandering of the paper 5. Therefore, in this case, a sensor abnormality can be detected by comparing the amount of deviation of the positions of the linear patterns 32k, 32c, 32m, and 32y from their normal positions with the sensor detection values SEk, SEc, SEm, and SEy.

In the first and second embodiments described above, the image position correction to compensate for the meandering of the paper 5 is performed by correcting the image data representing the printing target (image data correction configuration). , the recording head may be moved in the paper width direction (recording head moving configuration). Further, instead of moving the recording head in the paper width direction, the paper 5 may be moved in the paper width direction.

In the first and second embodiments described above, the linear pattern 32y to be recorded with Y color ink and the M color ink are used as inspection patterns capable of detecting a printing position shift in the paper width direction in order to detect a sensor abnormality. A JI pattern is used, which is composed of a linear pattern 32m to be recorded with C color ink, a linear pattern 32c to be recorded with C color ink, and a linear pattern 32k to be recorded with K color ink. (FIGS. 5 and 6), patterns that can be used as inspection patterns are not limited to this JI pattern. Instead of this JI pattern, inspect other patterns that can detect the misalignment of the printing position on the paper 5 (for example, the chart that can detect the direction and amount of misalignment of the paper 5 described in Japanese Patent Application Laid-open No. 2015-182364). It can also be used as a pattern.

In the sensor abnormality detection processing (FIGS. 10, 11, and 13) in the first and second embodiments and modifications described above, the presence or absence of an abnormality in the end sensor 25x (x=k, c, m, y) is indicated. The status value can take three status values: a status value ST0 indicating that the sensor is normal, a status value ST1 indicating the possibility of a sensor abnormality, and a status value ST2 indicating a sensor abnormality (see steps S112, S114, and S116). ), instead of this, the sensor may be configured to take only two status values: a status value indicating that the sensor is normal and a status value indicating that the sensor is abnormal. In this case, the process in step S114 is the same as step S116.

5...Paper (continuous recording medium)
10... Inkjet printing device 17... Printing control program 18... Sensor abnormality detection program 21... Recording head 20... Nozzle 25... Edge sensor 25k, 25c, 25m, 25y... Edge sensor 32k, 32c, 32m, 32y... Linear pattern 100...Control unit 111...CPU
200... Printing mechanism 205... Recording section 205k, 205c, 205m, 205y... Recording head row 209... Imaging section 302... JI pattern image (image of inspection pattern)
Le...Light emission range Dc, Dm, Dy...Distance between JI patterns

Claims (16)

a conveyance mechanism that conveys a long continuous recording medium unwound from a roll recording medium;
a recording unit that includes at least one recording head and records an image by ejecting ink from the at least one recording head onto the continuous recording medium;
The recording unit and the transport mechanism are configured such that an inspection pattern for detecting a deviation of a printing position on the continuous recording medium in the width direction of the continuous recording medium is recorded on the continuous recording medium together with an image to be printed. a recording control unit for controlling;
at least one edge sensor that detects a side edge position of the continuous recording medium;
a correction unit that corrects a print position of an image on the continuous recording medium according to a correction amount according to a value detected by the at least one edge sensor;
an imaging unit that reads the inspection pattern recorded on the continuous recording medium;
An inkjet printing apparatus, comprising: an abnormality detection section that determines whether or not there is an abnormality in the at least one edge sensor based on the correction amount and the image of the inspection pattern read by the imaging section. The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If the correction amount is outside a predetermined correctable range, determining that there is an abnormality in the at least one end sensor,
2. The apparatus according to claim 1, wherein when the correction amount is within the correctable range, the presence or absence of an abnormality in the at least one edge sensor is determined based on an image of the inspection pattern read by the imaging unit. Inkjet printing equipment. The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The inkjet printing apparatus according to claim 1, wherein the abnormality detection unit determines whether or not there is an abnormality in the at least one end sensor based on a temporal change in the correction amount and an image of the inspection pattern. The at least one recording head is composed of a plurality of recording heads arranged in the conveyance direction of the continuous recording medium, and the plurality of recording heads are configured to eject inks of different colors, respectively,
The at least one edge sensor includes a plurality of edge sensors each corresponding to the plurality of recording heads, and each of the plurality of edge sensors is configured to detect the continuous recording at the position of the corresponding recording head in the transport direction. configured to detect the side edge position of the medium;
The correction unit corrects the print position of the image on the continuous recording medium according to a plurality of correction amounts each corresponding to a value detected by the plurality of edge sensors,
The inkjet printing device according to claim 1, wherein the abnormality detection unit determines whether or not there is an abnormality in the plurality of edge sensors based on the plurality of correction amounts and the image of the inspection pattern read by the imaging unit. . The recording control unit is configured to eject ink from the plurality of recording heads at predetermined intervals from each other in the width direction, so that the plurality of linear patterns extending in the transport direction serve as the inspection patterns. controlling the recording unit and the transport mechanism so as to record on the continuous recording medium;
The abnormality detection unit determines the intervals between the plurality of linear patterns indicated by the image of the inspection pattern read by the imaging unit as an inter-pattern distance, and determines the interval between the plurality of linear patterns based on the plurality of correction amounts and the inter-pattern distance. The inkjet printing apparatus according to claim 4, wherein the inkjet printing apparatus determines whether or not there is an abnormality in the edge sensor. The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If any of the plurality of correction amounts is outside a predetermined correctable range, determining that there is an abnormality in one of the plurality of end sensors,
The inkjet printing apparatus according to claim 5, wherein when all of the plurality of correction amounts are within the correctable range, it is determined whether or not there is an abnormality in the plurality of edge sensors based on the distance between patterns. The abnormality detection section includes:
If all of the plurality of correction amounts are within the correctable range, but any of the inter-pattern distances is outside a predetermined tolerance range, any of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the plurality of correction amounts are within the correctable range and all of the inter-pattern distances are within the allowable range, it is determined that there is no abnormality in the plurality of edge sensors. The inkjet printing device according to claim 6. The recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium with the printing position corrected by the correction unit,
The abnormality detection section includes:
If any of the distances between the patterns is out of a predetermined tolerance range, determining that there is an abnormality in any of the plurality of edge sensors,
The inkjet printing apparatus according to claim 5, wherein when all of the inter-pattern distances are within the allowable range, it is determined whether or not there is an abnormality in the plurality of edge sensors based on the plurality of correction amounts. The abnormality detection section includes:
If any of the inter-pattern distances is within the allowable range, but any of the plurality of correction amounts is out of a predetermined correctable range, any one of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the inter-pattern distances are within the allowable range and all of the plurality of correction amounts are within the correctable range, it is determined that there is no abnormality in the plurality of edge sensors. The inkjet printing device according to claim 8. Claims 1 and 4, wherein the recording control unit controls the recording unit and the transport mechanism so that the inspection pattern is recorded on the continuous recording medium without the printing position being corrected by the correction unit. , or the inkjet printing device according to 5. The method includes a conveyance mechanism that conveys a long continuous recording medium unwound from a roll-shaped recording medium, and at least one recording head, and ink is ejected from the at least one recording head onto the continuous recording medium to form an image. a recording unit for recording; at least one edge sensor for detecting a side edge position of the continuous recording medium; and an image recording unit for recording images on the continuous recording medium according to a correction amount according to a detected value by the at least one edge sensor. An abnormality detection method for detecting an abnormality in the at least one end sensor in an inkjet printing apparatus including a correction unit that corrects a printing position, the method comprising:
a recording step of recording an inspection pattern on the continuous recording medium together with an image to be printed by the recording unit for detecting a deviation of a printing position on the continuous recording medium in the width direction of the continuous recording medium;
an imaging step of reading the inspection pattern recorded on the continuous recording medium;
An abnormality detection method, comprising: an abnormality detection step of determining whether or not there is an abnormality in the at least one end sensor based on the correction amount and the read image of the inspection pattern. The at least one recording head is composed of a plurality of recording heads arranged in the conveyance direction of the continuous recording medium, and the plurality of recording heads are configured to eject inks of different colors, respectively,
The at least one edge sensor includes a plurality of edge sensors each corresponding to the plurality of recording heads, and each of the plurality of edge sensors is configured to detect the continuous recording at the position of the corresponding recording head in the transport direction. configured to detect the side edge position of the medium;
The correction unit corrects the print position of the image on the continuous recording medium according to a plurality of correction amounts each corresponding to a value detected by the plurality of edge sensors,
In the recording step, a plurality of linear patterns extending in the transport direction are formed as the inspection patterns by ejecting ink from the plurality of recording heads at predetermined intervals from each other in the width direction. recorded on a continuous recording medium,
In the abnormality detection step, an interval between the plurality of linear patterns indicated by the image of the read inspection pattern is determined as an inter-pattern distance, and the distance between the plurality of edge sensors is determined based on the plurality of correction amounts and the inter-pattern distance. The abnormality detection method according to claim 11, wherein the presence or absence of an abnormality in is determined. In the recording step, the test pattern is recorded on the continuous recording medium with the printing position corrected according to the plurality of correction amounts,
The abnormality detection step includes:
determining that there is an abnormality in one of the plurality of end sensors when any one of the plurality of correction amounts is outside a predetermined correctable range;
13. The method according to claim 12, further comprising the step of determining whether or not there is an abnormality in the plurality of end sensors based on the inter-pattern distance when all of the plurality of correction amounts are within the correctable range. Anomaly detection method. In the abnormality detection step,
If all of the plurality of correction amounts are within the correctable range, but any of the inter-pattern distances is outside a predetermined tolerance range, any of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the plurality of correction amounts are within the correctable range and all of the inter-pattern distances are within the allowable range, it is determined that there is no abnormality in the plurality of edge sensors. The abnormality detection method according to claim 13. In the recording step, the test pattern is recorded on the continuous recording medium with the printing position corrected according to the plurality of correction amounts,
The abnormality detection step includes:
determining that there is an abnormality in one of the plurality of end sensors when any of the distances between the patterns is outside a predetermined tolerance range;
13. The abnormality according to claim 12, further comprising the step of determining whether or not there is an abnormality in the plurality of end sensors based on the plurality of correction amounts when all of the inter-pattern distances are within the allowable range. Detection method. In the abnormality detection step,
If any of the inter-pattern distances is within the allowable range, but any of the plurality of correction amounts is out of a predetermined correctable range, any one of the plurality of edge sensors It is determined that there is a possibility that there is an abnormality,
If all of the inter-pattern distances are within the allowable range and all of the plurality of correction amounts are within the correctable range, it is determined that there is no abnormality in the plurality of edge sensors. The abnormality detection method according to claim 15.

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