JP4120564B2 - Center position determining apparatus, center position determining method and printing apparatus for optical recording medium - Google Patents

Description

  The present invention relates to a center position determination device, a center position determination method, and a printing apparatus of an optical recording medium (hereinafter also referred to as “optical disk”), and in particular, to an optical recording medium or label recording in a printing apparatus. Center position determining device and center position determining method for determining the center position of an optical recording medium by scanning an optical recording medium tray on which the optical recording medium tray is placed using an optical sensor, and such a center position determining device It is related with the printing apparatus provided with.

  Optical disks such as CD-R and DVD-R have become widespread as recording media for recording various data.

  As the number of data-recorded optical discs increases in each home, workplace, etc., it becomes necessary to write titles on the label surface of the optical disc in order to organize and manage a large number of optical discs. .

  Although the title and the like can be written on the label surface of the optical disk by handwriting, there is a great demand for printing the label neatly, and therefore printing apparatuses capable of label printing of the optical disk are increasing.

In such a printing apparatus, an optical disk is placed on a dedicated disk tray, the optical disk is inserted into the printing apparatus together with the disk tray, and label printing of the optical disk is performed (see, for example, Patent Document 1).
JP 2002-127520 A

  By the way, an optical disk such as a CD-R or DVD-R is usually a circular disk in which an opening for rotation driving is formed at the center, and therefore the above-described label printing of the optical disk is performed with high quality. As one of the conditions, it is required to accurately detect and determine the center position of the optical disk.

  There are roughly two methods for detecting and determining the center position of an optical disc in the prior art.

  The first method is a method of calculating and determining the center position of the optical disc from the coordinates of the four peripheral portions of the optical disc detected by directly scanning the optical disc using an optical sensor.

  The second method uses an optical sensor in the same manner, but does not directly scan the optical disc, but instead of scanning the disc tray on which the optical disc is placed, the disc on the disc tray is determined from the coordinates of a plurality of locations on the disc tray. The center position of the mounting section is calculated, and under the assumption that the optical disk is normally mounted on the disk mounting section, the center position of the disk mounting section is regarded as the center position of the optical disk. This is a method for determining the center position.

  However, among optical discs such as CD-R and DVD-R that have been used recently, there are irregular discs such as a business card size of a substantially rectangular shape or an elliptical shape. Further, the label surface of a recording optical disk that is generally sold is not necessarily completely plain, and there are many cases in which characters, figures, and the like are printed in advance on a part thereof.

  Therefore, in the method of directly scanning the optical disc as in the first method, the center position of the optical disc may not be determined accurately.

  On the other hand, the position and size of the opening formed at the center of the recording optical disk manufactured and sold by various manufacturers with their own quality control vary somewhat. In some cases, the center position of the optical disk cannot be accurately determined even by a method in which only the disk tray is scanned to calculate the center position of the disk mounting portion and this is regarded as the center position of the optical disk.

  An object of the present invention is to provide a center of an optical recording medium capable of more accurately determining the center position of an optical disc such as a CD-R or DVD-R as an optical recording medium for label printing in a printing apparatus. A position determining apparatus, a center position determining method, and a printing apparatus are provided.

According to the optical recording medium center position determining apparatus according to the embodiment of the present invention,
A first scanning in a main scanning direction perpendicular to a printing medium conveyance direction of the printing apparatus, having a disk mounting portion formed as a concave portion for mounting an optical recording medium to be subjected to label printing by the printing apparatus; A vertical bisector that is located on a line and that is detectable by optical scanning and that is a line segment connecting the first and second position markers in the main scanning direction. Is positioned on the second scanning line in the sub-scanning direction parallel to the print medium conveyance direction, and the first and second position indicators arranged so as to pass through the center of the disk mounting portion. The third and fourth position markers that can be detected by optical scanning, and a perpendicular bisector connecting the third and fourth position markers in the sub-scanning direction is placed on the disk. The third portion disposed so as to pass through the center of the portion. A disc tray and a fourth position indicator Beauty,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. An optical sensor having a light receiving portion to
The surface of the optical recording medium mounted on the disk mounting portion is scanned by the optical sensor along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction, and the third sensor is scanned. A vertical bisector of the third scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium positioned on the scanning line and the fourth scanning A vertical bisector of the fourth scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium located on the line. The center position is specified, and the first and second position indicators are scanned by the optical sensor along the first scanning line and the second scanning line in the main scanning direction and the sub scanning direction. And the third and fourth position indicators From the vertical bisector between the first and second position markers identified from the mark and the vertical bisector between the third and fourth position markers, the disc tray Based on the result of specifying the center position, the center distance between the optical recording medium and the center position of the disc tray is calculated, the center distance is compared with a predetermined reference value, and the center distance is When the value is less than a reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the center-to-center distance is greater than or equal to the reference value, the disc mounting A controller for determining the center position of the unit as the center position of the optical recording medium;
It is characterized by having.

  In the above-described configuration of the optical recording medium center position determining apparatus according to the embodiment of the present invention, the predetermined reference value is a scanning result of the optical sensor when the optical recording medium is a circular optical disk. The distance may be equivalent to the distance corresponding to the maximum error between the center position of the optical recording medium specified based on the actual center position of the optical recording medium.

  Specifically, the predetermined reference value may be a value in the range of 0.4 mm to 0.5 mm.

According to the center position determination method of the optical recording medium according to one embodiment of the present invention,
A first scanning in a main scanning direction perpendicular to a printing medium conveyance direction of the printing apparatus, having a disk mounting portion formed as a concave portion for mounting an optical recording medium to be subjected to label printing by the printing apparatus; A vertical bisector that is located on a line and that is detectable by optical scanning and that is a line segment connecting the first and second position markers in the main scanning direction. Is positioned on the second scanning line in the sub-scanning direction parallel to the print medium conveyance direction, and the first and second position indicators arranged so as to pass through the center of the disk mounting portion. The third and fourth position markers that can be detected by optical scanning, and a perpendicular bisector connecting the third and fourth position markers in the sub-scanning direction is placed on the disk. The third portion disposed so as to pass through the center of the portion. A step of placing the optical recording medium to the disk loading portion of the disc tray and a position indicator for beauty 4,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. The surface of the optical recording medium placed on the disk placing portion is scanned along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction by an optical sensor having a light receiving portion that performs Then, the perpendicular bisector of the third scanning line between the two coordinates specified from the coordinates of the one end and the other end of the optical recording medium positioned on the third scanning line And the perpendicular bisector of the fourth scanning line between the coordinates specified from the coordinates of the one end and the other end of the optical recording medium located on the fourth scanning line Specifying the center position of the optical recording medium, and A disk tray is scanned by the optical sensor along the first and second scanning lines in the main scanning direction and the sub-scanning direction, and the first and second position indicators and the third and fourth positions are scanned. From the vertical bisector between the first and second position markers specified from the coordinates of the marker and the vertical bisector between the third and fourth position markers, the disc The process of identifying the center of the tray,
A center-to-center distance between the optical recording medium and the center position of the disc tray each specified based on a scanning result by the optical sensor is calculated, and the center-to-center distance is compared with a predetermined reference value. When the distance is less than the reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the distance between the centers is equal to or greater than the reference value, A process of determining the center position of the disk mounting portion as the center position of the optical recording medium;
It is characterized by having.

  In the above configuration of the optical recording medium center position determination method according to an embodiment of the present invention, the predetermined reference value is a scanning result of the optical sensor when the optical recording medium is a circular optical disk. The distance may be equivalent to the distance corresponding to the maximum error between the center position of the optical recording medium specified based on the actual center position of the optical recording medium.

  Specifically, the predetermined reference value may be a value in the range of 0.4 mm to 0.5 mm.

According to the printing apparatus according to the embodiment of the present invention,
A print medium transport mechanism for transporting the print medium;
A print head on which a plurality of ink discharge portions for discharging ink are formed;
On the first scanning line in the main scanning direction perpendicular to the printing medium conveyance direction, and having a disk mounting portion formed as a concave portion for mounting the optical recording medium as the printing medium to be subjected to label printing The first and second position markers that can be detected by optical scanning, and the perpendicular bisector connecting the first and second position markers in the main scanning direction is the first and second position markers. The first and second position indicators disposed so as to pass through the center of the disk mounting portion, and an optical element positioned on a second scanning line in a sub-scanning direction parallel to the print medium conveyance direction And a vertical bisector connecting the third and fourth position markers in the sub-scanning direction is a third bisector that can be detected by the formula scanning. The third and fourth are arranged to pass through the center. A disc tray and a position indicator, and the disc tray conveyed by the printing medium conveying mechanism with mounted on the disk mounting portion said optical recording medium,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. An optical sensor having a light receiving portion to
A carriage mounted with the print head and the optical sensor and driven in the main scanning direction on the print medium;
The surface of the optical recording medium mounted on the disk mounting portion is scanned by the optical sensor along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction, and the third sensor is scanned. A vertical bisector of the third scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium positioned on the scanning line and the fourth scanning A vertical bisector of the fourth scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium located on the line. The center position is specified, and the first and second position indicators are scanned by the optical sensor along the first scanning line and the second scanning line in the main scanning direction and the sub scanning direction. And the third and fourth position indicators From the vertical bisector between the first and second position markers identified from the mark and the vertical bisector between the third and fourth position markers, the disc tray Based on the result of specifying the center position, the center distance between the optical recording medium and the center position of the disc tray is calculated, the center distance is compared with a predetermined reference value, and the center distance is When the value is less than a reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the center-to-center distance is greater than or equal to the reference value, the disc mounting A controller for determining the center position of the unit as the center position of the optical recording medium;
It is characterized by having.

  In the configuration of the printing apparatus according to an embodiment of the present invention, the predetermined reference value is the optical recording specified based on a scanning result by the optical sensor when the optical recording medium is a circular optical disk. The distance may be equivalent to the distance corresponding to the maximum error between the center position of the medium and the actual center position of the optical recording medium.

  Specifically, the predetermined reference value may be a value in the range of 0.4 mm to 0.5 mm.

  The scanning in the main scanning direction by the optical sensor is performed by the driving operation of the carriage, and the scanning in the sub scanning direction parallel to the printing medium conveyance direction by the optical sensor is performed by the disk tray by the printing medium conveyance mechanism. It is good to carry out by this conveyance operation.

  According to the optical recording medium center position determining apparatus, the center position determining method, and the printing apparatus according to the present invention, an optical disk such as a CD-R or a DVD-R as an optical recording medium for label printing in the printing apparatus. The center position of can be determined more accurately. Specifically, both the center position of the optical disk based on the direct scanning of the optical disk and the center position of the disk mounting portion based on the scanning of the disk tray are specified, and it is estimated that the center position of the actual optical disk is close. Is adopted as the center position of the optical disc, so that the center location of the optical disc can be determined more accurately and with high accuracy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of an optical recording medium center position determining apparatus, a center position determining method, and a printing apparatus according to the present invention will be described with reference to the drawings.

  First, a schematic configuration of an ink jet printer which is a main application target of the configuration of the center position determining apparatus and center position determining method of the optical recording medium and the printing apparatus according to the present invention will be described.

  FIG. 1 is a perspective view showing a schematic configuration of a main part in an ink jet printer which is a main application target of the configuration of the center position determining apparatus, center position determining method, and printing apparatus of the optical recording medium according to the present invention.

  A printer 20 as an example of an ink jet printer is driven by a paper stacker 22, a motor (not shown), a conveyance roller 24 that conveys printing paper P as a printing medium, a platen plate 26, a carriage 28, and a carriage motor 30. A traction belt 32 driven by a carriage motor 30 and a guide rail 34 for guiding the carriage 28 are provided.

  The carriage 28 has a print head 36 having a plurality of nozzle rows each including a plurality of nozzles as ink ejection portions arranged along the transport direction (hereinafter also referred to as sub-scanning direction) of the printing paper P. , An optical sensor 41 as a determination device for determining whether or not ink is ejected from each nozzle, and a linear encoder 29 for reading the code plate 33 are mounted.

  A rotary encoder 25 is provided on the shaft of the transport roller 24, and the transport amount of the printing paper P is controlled based on the output of the rotary encoder 25. Accordingly, the position of the carriage 28 in the direction orthogonal to the printing paper conveyance direction (hereinafter also referred to as the main scanning direction) can be detected by the linear encoder 29, and the position of the printing paper P can be detected by the rotary encoder 25. is there. That is, the printer 20 is configured to be able to accurately recognize the relative position between the carriage 28 and the printing paper P based on the output signals of the encoders 25 and 29.

  The printing paper P is fed from the paper stacker 22 by a paper feeding roller (not shown), conveyed by the conveying roller 24, and sent on the surface of the platen plate 26 in the sub scanning direction SS.

  The carriage 28 is pulled by a pulling belt 32 driven by a carriage motor 30 and moves in the main scanning direction MS along the guide rail 34. The main scanning direction MS and the sub scanning direction SS are orthogonal to each other.

  FIG. 2 is a perspective view showing the arrangement of the nozzles and the optical sensor 41 when the print head 36 is viewed from above.

  The print head 36 includes a light black ink nozzle row KL for discharging light black ink, a light magenta ink nozzle row ML for discharging light magenta ink, and a light cyan ink nozzle for discharging light cyan ink. A line CL, a photo black ink nozzle line KP for discharging black ink mainly used for printing natural images, a dark black ink nozzle line KD for discharging dark black ink, and a dark cyan ink are discharged. There are provided a dark cyan ink nozzle row CD for discharging, a dark magenta ink nozzle row MD for discharging dark magenta ink, and a yellow ink nozzle row YD for discharging yellow ink. In this example, the first nozzle # 1 is arranged on the downstream side in the transport direction of the printing paper P.

  The optical sensor 41 mounted on the carriage 28 is disposed on the downstream side in the transport direction from the first nozzle # 1 of the yellow ink nozzle row YD located on the most anti-home position side of the print head 36, and further on the anti-home position side. Has been. In this example, for example, it is provided at a position of 8.58 mm downstream of the first nozzle in the yellow ink nozzle row YD in the transport direction and 51.75 mm on the non-home position side.

  A cleaning mechanism 200 is provided below the print head 36 mounted on the carriage 28 outside the print area within the movement range of the carriage 28 that moves along the guide rail 34. In FIG. 1, the cleaning mechanism 200 shows only the head cap 210, and other configurations are omitted.

  The head cap 210 is a confidential cap and covers the print head 36 when printing is not being performed to prevent the ink in the nozzles from drying. Therefore, the head cap 210 is provided at a standby position of the carriage 28, that is, a so-called home position side. Further, even when the nozzles are clogged, the print head 36 is covered with the head cap 210 and ink is sucked from the nozzles to perform cleaning.

  The optical sensor 41 that determines whether or not ink is ejected from each nozzle will be described in detail later.

  FIG. 3 is a block diagram showing an electrical configuration of the printer 20.

  The printer 20 includes a reception buffer memory 50 that receives a signal supplied from the host computer 100, an image buffer 52 that stores print data, a system controller 54 that controls the operation of the entire printer 20, and a main memory 56. ing.

  The system controller 54 includes a main scanning driver 61 that drives the carriage motor 30, a sub-scanning driver 62 that drives the conveyance motor 31, an optical sensor driver 63 that drives the optical sensor 41, and a head driver that drives the print head 36. 66 is connected.

  The optical sensor driver 63 includes a light amount control unit that can adjust the light emission amount of the light emitting unit 41 a provided in the optical sensor 41, and an output control unit that can adjust the output of the light receiving unit 41 b provided in the optical sensor 41. I have.

  Therefore, for example, it is possible to adjust the light emission amount of the light emitting unit 41a or the output of the light receiving unit 41b so that the output of the light receiving unit 41b that has received the light reflected by the predetermined printing paper becomes a predetermined value. The adjustment is performed by the system controller 54 controlling the optical sensor driver 63.

  A printer driver (not shown) of the host computer 100 determines various parameter values that define the printing operation based on the printing mode (high-speed printing mode, high-quality printing mode, etc.) designated by the user. The printer driver further generates print data for printing based on these parameter values, and transfers the print data to the printer 20.

  The transferred print data is temporarily stored in the reception buffer memory 50. In the printer 20, the system controller 54 reads necessary information from the print data stored in the reception buffer memory 50, and sends a control signal to each driver based on the read information.

  The image buffer 52 stores print data of a plurality of color components obtained by separating the print data received in the reception buffer memory 50 for each color component.

  The head driver 66 reads the print data of each color component from the image buffer 52 in accordance with a control signal from the system controller 54 and drives the nozzle row of each color provided in the print head 36 in accordance with this. The system controller 54 controls each part of the printer 20.

  Further, the print data transferred from the host computer 100 may be print data that has been separated for each color component before transfer from the host computer 100.

  FIG. 4 is an explanatory diagram schematically showing two types of configurations of the optical sensor.

  The optical sensor mounted on the printing apparatus can be used for various purposes. For example, in addition to the use as an optical sensor for ink discharge determination for determining the ink discharge state from the ink nozzles of the print head, it is reflected in the intensity of reflected light such as print pattern detection for Bi-D adjustment. The present invention can be widely used as a printing operation state determination device that determines various operation states of a printing apparatus by detecting the printing state on the surface of the printing medium or the presence or absence of the printing medium.

  The optical sensor mounted on the printing apparatus can also be used as an optical sensor that constitutes a center position determination device for an optical recording medium.

  Here, in order to explain the configuration and operating principle of the optical sensor, the optical sensor will be described as an optical sensor for ink ejection determination for convenience.

  As shown in FIG. 4A, the direction of the light emitting unit 41a is set so that the irradiation light La is irradiated perpendicularly to the surface of the printing paper as a printing medium, as an optical sensor for ink ejection determination. As shown in FIG. 4B, there is a configuration in which the direction of the light emitting portion 41a is set so that the irradiation light 41a is irradiated obliquely with respect to the surface of the printing paper as a printing medium. is there.

  As shown in FIGS. 4A and 4B, the optical sensor 41 for determining whether ink is ejected from the nozzle includes a light emitting unit 41a and a light receiving unit 41b. In the present embodiment, an example is shown in which one light receiving portion for mainly receiving the diffuse reflection component of the reflected light is provided as the light receiving portion 41b. It is good also as a structure which provided another light-receiving part for light-receiving a reflective component.

  The light emitting unit 41a is a light emitting device for irradiating light toward the printing paper. At the time of ink ejection determination, light is emitted toward an area of a printing paper on which a printing pattern including a printing block printed and formed corresponding to each nozzle by ink ejected from the nozzle is to be printed.

  In the normal configuration of the optical sensor 41, when the irradiation light from the light emitting unit is focused on the surface of the print medium, the area on which the printing paper is irradiated by the irradiation light (hereinafter referred to as “spot”). Spots are set so that one print block BL of the print pattern is included therein.

  Details of the print pattern will be described later.

  An arbitrary light emitting device such as a light emitting diode, a laser diode, or an incandescent bulb can be used for the light emitting unit 41a. The color of the irradiation light from the light emitting unit 41a is preferably a color that is complementary to the color of the determination target print image such as a print pattern. For example, red illumination light is used to detect a cyan print image, green illumination light is used to detect a magenta print image, and blue illumination light is used to detect a yellow print image. Good.

  When the color of the irradiation light and the color of the print image are in a complementary relationship, an output signal having a higher level can be obtained compared to the case where the color is not so.

  Therefore, in order to obtain a stable output for any color printed image, it is preferable to use a light emitting device whose irradiation light is white.

  The light receiving unit 41b is a photoelectric conversion device that detects reflected light reflected by the print pattern and converts it into an electrical signal. A photodiode, a phototransistor, or the like is preferably used as the light receiving element. Preferably, a light receiving element having good sensitivity characteristics with respect to visible light is used.

  It is desirable that the position of the light receiving portion 41b for mainly receiving the diffuse reflection component is not in the position of regular reflection with respect to the light emitting portion 41a.

  For example, as shown in FIG. 4A, the direction of the light emitting unit 41a is set so that the irradiation light from the light emitting unit 41a is irradiated perpendicularly to the surface of the printing paper as the printing medium, and from the surface of the printing paper. The direction of the light receiving portion 41b may be set so as to detect reflected light reflected obliquely. Alternatively, as shown in FIG. 4B, the direction of the light emitting unit 41a is set so that the irradiation light from the light emitting unit 41a is obliquely irradiated to the surface of the printing paper as the printing medium, and the surface of the printing paper is Alternatively, the direction of the light receiving unit 41b may be set so as to detect reflected light perpendicular to the light receiving unit 41b.

  In particular, in a print medium having a coating layer formed on the surface thereof, such as glossy printing paper, most of the incident light is regularly reflected by the coating layer on the surface, but the light receiving unit 41b is opposed to the light emitting unit 41a. If it is not attached at the regular reflection position, the color of the printing block under the coating layer can also be reliably determined.

  The irradiation light emitted from the light emitting unit 41a is reflected by the printing paper on which the printing block is printed, and the diffuse reflection component of the reflected light reaches the light receiving unit 41b. The light receiving unit 41b generates an electrical signal corresponding to the detected intensity of the reflected light and outputs it as an output signal.

  When the level of the output signal is smaller than a preset threshold value, it is determined that the ink is normally ejected from the nozzle that should form the print block irradiated with the irradiation light from the light emitting unit 41a, and the level of the output signal is determined. Is equal to or greater than the threshold value, it is determined that ink was not normally ejected from the nozzle.

  At this time, for example, the optical sensor 41 detects the level of the output signal from the light receiving unit 41b that detects the reflected light reflected by a predetermined unused printing paper, a printing pattern of each color printed on a predetermined printing medium, or the like. Is adjusted by the light amount control unit of the optical sensor driver 63 controlled by the system controller 54, or the light receiving unit 41b is adjusted by the output control unit of the optical sensor driver 63. The output of has been adjusted.

  When a plurality of light emitting devices are compared, there is an individual difference even if the same white light emitting device is used, and a difference occurs in the output value when a specific print pattern is irradiated.

  Accordingly, the light emitting device is configured by adjusting the light emission amount of the light emitting unit or the output of the light receiving unit by using the actually mounted optical sensor, the actual print medium, and the print pattern printed by the actual ink. It is possible to prevent misjudgment that may occur due to the individual difference between the two, the type of print medium, the type of ink color, and the like.

  Hereinafter, in order to clarify the operation principle of the optical sensor, the contents of the ink ejection inspection using the optical sensor as the optical sensor for ink ejection determination will be described.

  FIG. 5 is an explanatory view schematically showing an example of an inspection pattern printed and formed with one color ink, and FIG. 6 is an explanatory view schematically showing an inspection print block BL constituting the inspection pattern. is there.

  In the ink ejection inspection, first, an inspection pattern is created. This test pattern is a test pattern that is printed and formed for each ink color by a nozzle row that ejects ink of each color. That is, when inspecting the ink ejection states of all the nozzles, inspection patterns corresponding to the number of colors of ink ejected from the nozzle rows of the print head 36 are formed.

  Therefore, in this embodiment, eight inspection patterns are created. Further, N print blocks BL are printed in an inspection pattern when N nozzles are arranged in a single color nozzle row and the N nozzles are inspected.

  The test pattern is composed of a plurality of test print blocks BL formed for each nozzle by the ink ejected from each nozzle, and one print block BL includes a plurality of ink dots PX as shown in FIG. It is formed by.

  Since one printing inspection block BL is formed by printing only with ink ejected from one nozzle, one printing inspection block BL is used for inspection of one nozzle corresponding thereto. FIG. 5 shows an inspection pattern formed by a nozzle row having 54 nozzles.

  This inspection pattern is configured by nine inspection print blocks BL arranged in the main scanning direction (left-right direction) and six in the sub-scanning direction. That is, six inspection print block arrays each including nine inspection print blocks arranged in the main scanning direction are formed in the sub-scanning direction.

  The first-stage inspection print block array located on the most downstream side in the transport direction is printed by the ninth nozzle # 9 to the first nozzle # 1, and the second-stage inspection print block array is the 18th nozzle. Printing is performed from # 18 to No. 10 nozzle # 10. Similarly, the sixth-stage inspection print block array is printed from No. 54 nozzle # 54 to No. 46 nozzle # 46.

  When printing each inspection printing block array constituting the inspection pattern, for example, the carriage 28 is scanned from the left side to the right side in FIG. No. 36, No. 27, No. 18, No. 9 nozzles # 54, # 45, # 36, # 27, # 18, # 9 are ejected to form a predetermined number of dots to form the main print block BL for inspection. Print only the width in the scanning direction. The carriage 28 continues to scan and ejects ink from nozzles # 53, # 44, # 35, # 26, # 17, and # 8, # 53, # 44, # 35, # 26, # 17, and # 8. A dot row or a line is formed by a predetermined number of dots for forming the inspection print block of the second row.

  As described above, each nozzle constituting the nozzle row is grouped into nozzles corresponding to the number of test print blocks arranged in the main scanning direction of the test pattern in order to form sub nozzle groups. Each inspection print block is formed by ejecting ink for each nozzle located in the same order in the sub-scanning direction.

  When the scanning by the carriage 28 from the left side to the right side in FIG. 5 is completed, the printing paper is conveyed by the nozzle pitch in the sub scanning direction. Thereafter, scanning by the carriage 28 is performed from the right side to the left side, and ink is ejected from a predetermined nozzle in the reverse order to the previous scanning to form a dot row or line.

  As described above, an operation for transporting printing paper by the nozzle pitch in the sub-scanning direction, and an operation for performing scanning in the main scanning direction while ejecting ink for each nozzle located in the same order in the sub-scanning direction of each sub-nozzle group. When nine dot rows or lines are formed, an inspection print block is formed. When ink is normally ejected from all the nozzles, an inspection pattern having 54 inspection print blocks is finally printed.

  As can be seen from FIG. 5, the inspection print blocks adjacent to each other in the main scanning direction (left-right direction), for example, the inspection print block formed by the 54th nozzle # 54 and the 53rd nozzle # 53 are used. The formed inspection print block is printed at a position shifted by the nozzle pitch in the sub-scanning direction.

  The dots forming each test print block are formed at equal intervals between the test print blocks adjacent to each other, and no blank portion is generated between the test print blocks.

  In the present embodiment, the conveyance amount in the conveyance of the printing paper executed during each scan of the carriage 28 is the nozzle pitch. However, the conveyance amount is arbitrary, and for example, the conveyance amount is half the nozzle pitch. The number of dots constituting each inspection print block increases, and the density of each inspection print block increases. At this time, the number of dot rows or lines constituting each inspection print block is 18.

  FIG. 7 is an explanatory diagram schematically showing the locus of spots on the inspection pattern during scanning by the optical sensor. As described above with reference to FIG. 5, the inspection print blocks adjacent to each other in the main scanning direction are printed at positions shifted by the nozzle pitch in the sub-scanning direction. In FIG. 7, for simplification, an inspection pattern 71 is shown in a state where the inspection print blocks are arranged and formed in a matrix without any deviation.

  When determining the presence or absence of ink ejection, the optical sensor 41 attached to the carriage 28 (FIG. 1) and the printing paper P are relatively moved, and the optical sensor 41 scans the inspection print block BL.

  At this time, the spot of the irradiation light La (FIG. 4) from the light emitting unit 41a of the optical sensor 41 is sequentially applied to each inspection print block BL as shown by the locus XY in FIG. The reflected light Lb is detected by the light receiving unit 41b, and the presence or absence of ink ejection is determined by comparing the level of the electrical signal output from the light receiving unit 41b with a predetermined threshold according to the detected intensity of the reflected light Lb. The comparison between the output signal level and a predetermined threshold is performed for each inspection print block BL.

  As shown in FIG. 2, when the optical sensor 41 is arranged downstream of all the nozzles of the print head 36, a part of the upstream side of a part of the printing blocks BL on the downstream side is used. In the movement operation of the carriage 28 when printing the printing block BL, scanning by the optical sensor 41 is performed, and at the same time, the presence or absence of ink ejection is determined. On the other hand, unlike the example shown in FIG. 2, when the optical sensor 41 is disposed on the upstream side of the print head 36, the print medium is temporarily moved in the print medium conveyance direction after the printing of all the print blocks BL is completed. After feeding back to the upstream side, the optical sensor 41 performs scanning while transporting the print medium to the downstream side again, and at the same time, the presence or absence of ink ejection is determined.

  Further, the area irradiated with the printing paper by the light emitted from the light emitting unit 41a of the optical sensor 41 is a circular spot on the printing paper, but in this embodiment, the inspection printing block BL is included in the spot. Spots are set to include one.

  FIG. 8 is a graph showing the relationship between the output signal level and the determination threshold in determining whether or not ink is ejected.

  When there is a nozzle from which ink is not ejected due to clogging, the printing block corresponding to the nozzle among the inspection printing blocks BL formed on the printing paper is a blank printing block BLa in which ink is not dropped.

  When the printing block irradiated by the spot of the irradiation light emitted from the light emitting unit 41a of the optical sensor 41 is the blank printing block BLa, the intensity of the reflected light Lb detected by the light receiving unit 41b of the optical sensor 41 increases. The output signal level converted according to the detected intensity of the reflected light Lb increases.

  On the other hand, when the printing block irradiated by the spot is a normal printing block BLb printed normally, the intensity of the reflected light Lb detected by the light receiving unit 41b decreases, so that it depends on the detected intensity of the reflected light Lb. The output signal level to be converted is lowered.

  That is, the output signal level VL when the spot formed by the light emitting unit 41a scans the blank printing block BLa is a relatively high value, and the output signal level V0 when the spot scans the normal printing block BLb is relatively high. A low value.

  Therefore, as shown in FIG. 8, by setting the determination threshold Vth between the output signal level VL corresponding to the blank print block BLa and the output signal level V0 corresponding to the normal print block BLb, the output signal By comparing the level with the determination threshold value Vth, it is possible to determine whether or not ink is ejected from each nozzle.

  The hardware operation when determining whether or not to discharge ink as described above is as follows.

  The determination unit 54 a of the system controller 54 (FIG. 3) compares the output signal level from the optical sensor 41 with a determination threshold value Vth that is set in advance and stored in the main memory 56 in order to determine the presence or absence of ink ejection. .

  When the output signal level is smaller than the threshold value Vth, the print block included in the spot is a normal print block printed normally, and ink is normally ejected from the nozzle used for printing the print block. Is determined. On the other hand, when the output signal level is larger than the threshold value Vth, the printing block included in the spot is a blank printing block in which ink has not been dropped, and ink is normally discharged from the nozzle used for printing the printing block. It is determined that the ink is not discharged.

  The printer 20 has a configuration in which one printing block is included in a region where the printing paper is irradiated by the irradiation light from the light emitting unit 41a, that is, the output of the linear encoder 29 and the output of the rotary encoder 25. The relative position between the carriage 28 and the printing paper can be recognized, and the relative position between the optical sensor 41 provided on the downstream side of all the nozzles in the transport direction and each nozzle is accurately adjusted and recognized in advance. It shall be.

  Therefore, when a blank print block in which ink has not been dropped is detected as a result of scanning the inspection print block by the optical sensor 41 by the scanning operation of the carriage 28 in order to determine the presence or absence of ink ejection. Based on the outputs of the linear encoder 29 and the rotary encoder 25, it is possible to identify the nozzle corresponding to the blank print block as an abnormal nozzle in which ink ejection is not normally performed.

  When an abnormal nozzle that does not eject ink normally is identified, flushing or the like is performed only on the abnormal nozzle to restore it to a good state, or other dots that should be originally formed by the abnormal nozzle It is also possible to form and print using this nozzle.

  FIG. 9 is a graph showing the relationship between the light reception output signal waveform of the optical sensor and the determination threshold.

  As described above, when the printing block irradiated by the spot of the optical sensor is a normal printing block BLb printed normally, the intensity of the reflected light Lb detected by the light receiving unit 41b decreases, and thus the detected reflection is detected. The output signal level converted according to the intensity of the light Lb decreases. Therefore, the output signal level V0 when the spot scans the normal printing block BLb becomes a relatively low value, and the received light output signal waveform varies with this output signal level V0 as a reference level.

  On the other hand, when the printing block irradiated by the spot of the optical sensor is the blank printing block BLa, the intensity of the reflected light Lb detected by the light receiving unit 41b of the optical sensor 41 increases, so the intensity of the detected reflected light Lb The output signal level converted in response to rises. Therefore, the output signal level VL when the spot formed by the light emitting portion 41a scans the blank print block BLa is a relatively high value, and the peak of the maximum value VL is present in the received light output signal waveform as shown in FIG. As observed.

  Therefore, normally, by setting the determination threshold Vth between the output signal level V0 serving as the reference level and the output signal level VL serving as the peak level, the sensor light reception output signal level and the determination threshold Vth are set. In comparison, the presence or absence of ink ejection at each nozzle can be determined.

  In addition, when using what has the reverse output characteristic as what is assumed in this embodiment as an optical sensor, or the whole circuit including the optical sensor is assumed in this embodiment. When using a sensor with output characteristics opposite to that of the sensor, the signal level of the sensor light reception output is high when the intensity of the reflected light detected is small, and the signal level of the sensor light reception output is high when the intensity of the reflection light is large. Becomes lower.

  As described above, the optical sensor mounted on the printing apparatus is not limited to the use as an optical sensor for ink ejection determination, but is used for detecting the intensity of reflected light such as print pattern detection for Bi-D adjustment. It can be widely used as a printing operation state determination device for determining various operation states of the printing apparatus by detecting the reflected printing state of the surface of the printing medium or the presence or absence of the printing medium, and further, the center of the optical recording medium It can also be used as an optical sensor constituting the position determining device.

  FIG. 10 is a plan view showing the form of a standard optical disc.

  A standard form of an optical disc such as a CD-R or DVD-R is a circular optical disc 81 having a diameter of 120 mm as shown in FIG. 10A (not shown), and is driven to rotate at the center. An opening 81a is provided. This standard form of the optical disk 81 is the most widely used form of optical disk.

  Further, as a standard form optical disc having a relatively small recordable data capacity, a single-size optical disc 82 having a diameter of 80 mm as shown in FIG.

  The two types of optical disks 81 and 82 shown in FIGS. 10A and 10B are circular optical disks having different diameters but having a constant radius over the entire circumference.

  In each home, workplace, etc., optical discs have recently been widely used as recording media for recording various data. However, as the number of optical discs on which data has been recorded increases, In order to organize and manage a large number of optical discs, it becomes necessary to write titles on the label surface of the optical discs.

  In response to the demand for beautifully printing a label when describing a title or the like on the label surface of the optical disk, printing apparatuses capable of label printing of the optical disk are increasing.

  In a printing apparatus capable of label printing on an optical disk, the optical disk is usually placed on a dedicated disk tray, and the optical disk is inserted into the printing apparatus together with the disk tray to perform label printing on the optical disk.

  FIG. 11 is a plan view (a) and a cross-sectional view (b) showing the structure of the disc tray on which the optical disc is placed. FIG. 11B is a cross-sectional view taken along the cutting plane AA ′ shown in FIG.

  The disc tray 110 is a flat plate tray formed by molding a resin material or the like, and a first circular recess 110a as a first disc placement portion for placing the optical disc 81 is formed on the upper surface. A second circular recess 110b as a second disk mounting portion for mounting a single-size optical disk 82 is further formed at the center of one circular recess 110a.

  When performing label printing of the optical disc 81, the optical disc 81 is placed on the first circular recess 110a, and when performing label printing of the optical disc 82, the optical disc 82 is placed on the second circular recess 110b. Then, the optical disc 81 or the optical disc 82 is inserted into the printing apparatus together with the disc tray 110, and label printing is executed.

  FIG. 12 is a perspective view illustrating an example of a state when label printing is performed by inserting the optical disk placed on the disk tray into the printing apparatus.

  In this example, the disc tray 110 on which the optical disc 81 is placed is inserted as indicated by an arrow (1) from the front side of the printing apparatus, and the disc tray 110 is fed back into the printing apparatus by the printing medium transport mechanism of the printing apparatus. After determining the center position of the optical disk, label printing is performed while transporting the disk tray 110 by a predetermined transport amount from the label printing start position in the print medium transport direction as indicated by the arrow (2).

  Contrary to this example, the disc tray 110 on which the optical disc 81 is placed is inserted from the back side of the printing apparatus, and the disc tray 110 is moved into the printing apparatus by the printing medium conveyance mechanism of the printing apparatus in the printing medium conveyance direction. After transporting and determining the center position of the optical disk, label printing may be performed while transporting the disk tray 110 by a predetermined transport amount from the label printing start position in the print medium transport direction.

  As described above, when performing label printing on an optical disk, it is necessary to determine the center position of the optical disk in advance before starting printing in order to perform label printing at an accurate position.

  The method for determining the center position of the optical disk in the existing printing apparatus can be broadly divided into a method for directly detecting the optical disk and calculating and determining the center position of the optical disk, and a method for detecting the disk tray on which the optical disk is placed and detecting the disk tray. There is a method in which the center position is calculated, and the center position of the optical disk is determined by regarding the center position of the disk tray as the center position of the optical disk.

  Hereinafter, the two methods for determining the center position of the optical disc will be described. In either method, an optical sensor is used to detect an optical disk or a disk tray.

  FIG. 13 is a graph (a) showing a sensor light reception output when detected by directly scanning an optical disk with an optical sensor, and a side sectional view (b) showing the state.

  Here, it is assumed that the disc tray is molded of black resin, and the label surface of the optical disc is processed into a surface form having a relatively higher reflectance than the disc tray.

  As shown in FIG. 13B, when the optical sensor 41 is scanned from the one end to the other end by the optical sensor 41, the first circular recess 110a of the disc tray is scanned. While the optical sensor scans the surface of the disk tray 110 around the optical disk 81, the intensity of the reflected light from the surface of the disk tray 110 is small, so that the sensor light reception output has a relatively small signal level V1. .

  The irradiation spot 10 of the optical sensor 41 moves to the one end E1 of the optical disk 81 located on the scanning line, and the area irradiated by the spot 10 shifts from the disk tray 110 surface to the label area surface of the optical disk 81. Then, since the intensity of the reflected light from the surface of the optical disc 81 becomes larger than the intensity of the reflected light from the surface of the disk tray 110, the sensor light reception output rises to a signal level V3 that is larger than the signal level V1.

  Thereafter, while the irradiation spot 10 of the optical sensor 41 irradiates the surface of the label area of the optical disc 81, the sensor light reception output remains constant at the signal level V3, but the spot 10 is positioned on the scanning line of the optical disc 81. When moving to one end P1 of the transparent or semi-transparent portion near the central opening 81a, the intensity of the reflected light from the surface of the optical disc 81 decreases, and the sensor light reception output decreases to the signal level V2.

  Further, when the irradiation spot 10 of the optical sensor 41 moves to the central opening 81a of the optical disk 81, the spot 10 irradiates the surface of the disk tray 110, so that the sensor light reception output further decreases to the signal level V1.

  The irradiation spot 10 of the optical sensor 41 irradiates a region up to the other end portion P2 of the transparent or translucent portion in the vicinity of the central opening 81a located on the scanning line across the central opening 81a of the optical disc 81. Then, the intensity of the reflected light from the surface of the optical disc 81 increases, and the sensor light reception output increases to the signal level V2.

  Further, when the irradiation spot 10 of the optical sensor 41 passes through the other end P2 of the transparent or translucent portion near the central opening 81a located on the scanning line of the optical disc 81 and moves to the label area surface, the sensor The light reception output rises to a signal level V3 that is higher than the signal level V2.

  After that, when the irradiation spot 10 of the optical sensor 41 passes through the other end E2 of the optical disk 81 located on the scanning line and irradiates the surface of the disk tray 110, the sensor light reception output again reaches the signal level V1. descend.

  As described above, as a result of directly scanning the optical disk 81 by the optical sensor 41, the signal waveform shown in FIG.

  Therefore, first, in order to detect the position E1 where the irradiation spot 10 of the optical sensor 41 starts to irradiate the surface of the label area of the optical disk 81 and the position E2 where the irradiation ends, the signal level V2 and the signal level V3 A threshold value Vthd is set, and a position E1 where the signal waveform of the sensor light reception output first passes the threshold value Vthd and a position E2 where the signal waveform passes last are specified.

  Then, when the midpoint C1 between the one end E1 and the other end E2 is calculated from the coordinates of the one end E1 and the other end E2 of the optical disc 81 located on the scanning line by the optical sensor, The center of the optical disk is located on the scanning line connecting the one end E1 and the other end E2 of the optical disk 81, that is, on the perpendicular bisector of the locus of the irradiation spot 10.

  Therefore, the scanning lines of the optical sensor are set in the main scanning direction and the sub-scanning direction in the printing apparatus, respectively, and two vertical lines connecting the one end and the other end of the optical disc 81 detected in each scanning line. When the intersection point between equal lines is calculated, the intersection point is the center of the optical disc.

  As described above, in the present embodiment, when an optical sensor having an output characteristic opposite to that assumed in the present embodiment is used, or the entire circuit including the optical sensor is used in the present embodiment. When using a sensor with output characteristics opposite to the expected one, the signal level of the sensor light reception output is high when the detected reflected light intensity is low, and the sensor light reception when the reflected light intensity is high. The output signal level is lowered. Therefore, in that case, the graph of FIG. 13A is a signal waveform that is inverted up and down with respect to the median value of the sensor light reception output.

  FIG. 14 is an explanatory diagram schematically showing a process of determining the center of the optical disc. In FIG. 14, in order to make the drawing easier to see, the scanning line by the optical sensor is drawn largely shifted from the center of the optical disk.

  In the manner described with reference to FIG. 13, first, the optical sensor 41 is scanned by the optical sensor 41 along the main scanning direction scanning line SCN1, and one side end of the optical disk 81 positioned on the main scanning direction scanning line SCN1. The coordinates of the portion Q11 (MX1, MY3) and the other end Q12 (MX2, MY3) are detected, and the one end Q11 (MX1, MY3) and the other end Q12 (MX2, MY3) are connected. The coordinates of the midpoint C1 (MX, MY3) of the line segment are calculated.

  Also, the optical sensor 41 similarly scans the optical disk 81 along the sub-scanning direction scanning line SCN2 orthogonal to the main scanning direction scanning line SCN1, and one side of the optical disk 81 positioned on the sub-scanning direction scanning line SCN2 The coordinates of the end Q21 (MX3, MY1) and the other end Q22 (MX3, MY2) are detected, and the one end Q21 (MX3, MY1) and the other end Q22 (MX3, MY2) are detected. The coordinates of the midpoint C2 (MX3, MY) of the connecting line segment are calculated.

  Then, a vertical bisector connecting the one end Q11 (MX1, MY3) and the other end Q12 (MX2, MY3) of the optical disk on the main scanning direction scanning line SCN1, and scanning in the sub scanning direction. When the intersection coordinates of the perpendicular bisector connecting the one end Q21 (MX3, MY1) and the other end Q22 (MX3, MY2) of the optical disk on the line SCN2 are specified, the intersection is This is the center C (MX, MY) of the optical disc 81, and this is determined as the center of the optical disc 81. The determined coordinates of the center position of the optical disc 81 are used as a reference for position control during label printing.

  Note that the scanning of the main scanning direction scanning line SCN1 and the scanning of the sub scanning direction scanning line SCN2 may be performed first, and are in no particular order. The scanning by the optical sensor 41 along the main scanning direction scanning line SCN1 is performed by driving the carriage on which the optical sensor 41 is mounted in the main scanning direction, and the optical sensor along the sub scanning direction scanning line SCN2. In the scanning by 41, the carriage on which the optical sensor 41 is mounted is stopped at any position in the main scanning direction, and the disc tray 110 is moved in the sub scanning direction, that is, the printing medium conveying direction by the printing medium conveying mechanism of the printing apparatus. By moving to.

  By the way, most of the optical disks such as CD-R and DVD-R that are widely used have the form of the circular optical disk shown in FIG. 10, but the forms of the recent optical disks are diversified. There are various types of deformed optical discs.

  FIG. 15 is a plan view showing an example of a modified optical disk.

  The irregularly-shaped discs that have been used recently include, for example, various forms such as a substantially rectangular optical disc having a business card size shown in FIG. 15 (a) and an elliptical optical disc shown in FIG. 15 (b). As long as there is no hindrance to the rotational drive for reading, the optical disk can be formed in an arbitrary form.

  In addition, even in the case of a standard circular optical disk, the label surface of a recording optical disk that is generally sold is not necessarily completely plain, and there are many cases in which characters, figures, and the like are preprinted in part.

  When the optical disk to be printed with a label is an irregular optical disk other than a circle, if the method of directly scanning the optical disk with an optical sensor as described above is used to determine the center position of the optical disk, Since the center of the optical disc is not always located on the perpendicular bisector connecting the ends of the two points detected in step 1, the center position of the optical disc may not be determined accurately.

  In addition, when characters, figures, etc. are printed in advance on a part of the label surface of the optical disk to be printed, the optical disk is directly scanned by the optical sensor as described above in order to determine the center position of the optical disk. If the method is adopted, the signal waveform of the sensor light-receiving output is disturbed due to the influence of characters or figures printed on the label surface, and the two end portions of the optical disk positioned on the scanning line are accurately specified. As a result, the center position of the optical disc may not be determined accurately.

  Therefore, as a second method that can be applied to various types of optical discs, an optical sensor is similarly used. However, instead of directly scanning the optical disc, the center of the optical disc is scanned by scanning the disc tray on which the optical disc is placed. There is a way to determine the position. In this method, the coordinates of the center position of the disk mounting portion of the disk tray are calculated from the coordinates of a plurality of positions (usually four positions) on the disk tray detected by scanning the disk tray on which the optical disk is mounted. This is a method of determining the center position of the optical disc by regarding the center position of the disc placement portion as the center location of the optical disc under the assumption that the disc is normally placed on the disc placement portion.

  FIG. 16 is a plan view showing the configuration of the disc tray used in the center position determining device and the center position determining method for determining the center position of the optical disc by scanning the disc tray.

  The disk tray 111 used in the center position determining apparatus and the center position determining method for determining the center position of the optical disk by scanning the disk tray is a main scanning of the optical sensor in the main scanning direction orthogonal to the print medium transport direction of the printing apparatus. The vertical bisector of two position markers located on the direction scanning line TSCN1 and connecting the two position markers in parallel to the main scanning direction scanning line TSCN1 is a disk placement portion 111a of the disk tray 111. Two position indicators 111X1 and 111X2 arranged so as to pass through the center of the optical sensor, and two optical sensors positioned on the scanning line TSCN2 in the sub scanning direction of the optical sensor in the sub scanning direction parallel to the print medium conveyance direction. A vertical bisector that is a position marker and connects the position markers in parallel to the sub-scanning direction scanning line TSCN2 And two position indicator 111Y1,111Y2 which are arranged to pass through the center of the disk mounting portion 111a of Kutorei 111, and a.

  Further, the disc tray 111 is a plate-like tray formed by molding a resin material or the like, similar to the disc tray 110 in FIG. 11 except that the two sets (four pieces) of position markers are disposed. A first circular recess 111a for mounting the optical disc 81 is formed on the upper surface, and a second circular recess for mounting a single-size optical disc 82 further on the center of the first circular recess 111a. A portion 111b is formed.

  In the method of determining the center position of the optical disc by scanning the disc tray, the optical disc 81 is placed on the disc placement portion 111a of the disc tray 111 with the position indicator and inserted into the printing apparatus. The disk tray 111 is scanned to detect each position mark, the coordinates of the center position of the disk mounting portion 111a are calculated from the coordinates of each position mark, and the coordinates are regarded as the coordinates of the center position of the optical disk. Determine the center position.

  A specific process for determining the center position of the optical disc by scanning the disc tray is as follows. First, the optical tray 41 scans the disk tray 111 along the main scanning direction scanning line TSCN1, and the first position indicator 111X1 and the second position indicator of the disk tray 111 located on the main scanning direction scanning line TSCN1. 111X2 X coordinates (main scanning direction coordinates) TX1, TX2 are detected, and the X coordinate TX = (TX1 + TX2) / 2 of the midpoint of the line segment connecting the first position mark 111X1 and the second position mark 111X2 Is calculated. For the first position mark 111X1 and the second position mark 111X2 located on the main scanning direction scanning line TSCN1 and the coordinates of their midpoints, not only the X coordinate but also the Y coordinate (sub-scanning direction coordinate) is detected. However, the Y coordinate of each position is omitted here because it is not necessary to calculate the coordinates of the center position of the disk mounting portion 111a.

  On the other hand, the optical sensor 41 similarly scans the disk tray 111 along the sub-scanning direction scanning line TSCN2 orthogonal to the main scanning direction scanning line TSCN1, and the disk tray 111 positioned on the sub-scanning direction scanning line TSCN2 is scanned. The Y coordinates TY1, TY2 of the third position indicator 111Y1 and the fourth position indicator 111Y2 are detected, and the Y coordinate TY of the midpoint of the line segment connecting the third position indicator 111Y1 and the fourth position indicator 111Y2 = (TY1 + TY2) / 2 is calculated. For the third position indicator 111Y1 and the fourth position indicator 111Y2 located on the sub-scanning direction scanning line TSCN2 and the coordinates of their midpoints, not only the Y coordinate but also the X coordinate may be detected and calculated. However, the X coordinates of these positions are omitted here because they are not necessary for calculating the coordinates of the center position of the disk mounting portion 111a.

  A vertical bisector connecting a first position indicator 111X1 and a second position indicator 111X2 on the main scanning direction scanning line TSCN1, and a third position indicator 111Y1 and the second position indicator on the sub-scanning direction scanning line TSCN2. When the intersection coordinates with the vertical bisector connecting the four position markers 111Y2 are specified, the intersection is the center of the disk loading portion 111a of the disk tray 111.

  The coordinates of the center position of the disk mounting portion 111a are the X coordinate TX = (TX1 + TX2) / 2 of the midpoint of the line segment connecting the first position indicator 111X1 and the second position indicator 111X2, and the third position. This is a combination of the Y coordinate TY = (TY1 + TY2) / 2 of the midpoint of the line segment connecting the marker 111Y1 and the fourth position marker 111Y2.

  Therefore, as described above, the X coordinates TX1, TX2 of the first position mark 111X1 and the second position mark 111X2 of the disc tray 111 positioned on the main scanning direction scanning line TSCN1, and the sub scanning direction scanning line TSCN2 By detecting the Y coordinates TY1, TY2 of the third position indicator 111Y1 and the fourth position indicator 111Y2 of the disc tray 111 located at the position, the coordinates of the center position of the disc mounting portion 111a can be calculated.

  Then, the coordinates of the center position of the disk mounting portion 111 a are regarded as the coordinates of the center position of the optical disk 81 and determined as the center of the optical disk 81. The determined coordinates of the center position of the optical disc 81 are used as a reference for position control during label printing.

  As in the case of directly scanning the optical disk 81, the scanning of the main scanning direction scanning line TSCN1 and the scanning of the sub scanning direction scanning line TSCN2 may be performed first, and are in no particular order. The scanning by the optical sensor 41 along the main scanning direction scanning line TSCN1 is performed by driving the carriage on which the optical sensor 41 is mounted in the main scanning direction, and the optical sensor along the sub scanning direction scanning line TSCN2. In the scanning by 41, the carriage on which the optical sensor 41 is mounted is stopped at a position within the range of the X coordinate corresponding to the width of the third position indicator 111Y1 and the fourth position indicator 111Y2 in the main scanning direction, and printing is performed. This is performed by moving the disc tray 110 in the sub-scanning direction, that is, in the print medium conveyance direction by the print medium conveyance mechanism of the apparatus.

  In the above method for determining the center position of the optical disk by scanning the disk tray, the center of the optical disk 81 is determined regardless of the form of the optical disk, so that the coordinates of the center position of the optical disk 81 can be specified relatively accurately. .

  However, the position and size of the opening formed in the center of a recording optical disk such as CD-R, DVD-R, etc., which are manufactured and sold by various manufacturers with their own quality control, Since there is a variation, as described above, when only the disk tray is scanned to calculate the center position of the disk mounting portion and this is regarded as the center position of the optical disk, it is between the actual center position of the optical disk. It is possible that a gap will occur.

  Eventually, in the method of directly scanning the optical disk 81, it is possible to determine a relatively accurate center position, but when a deformed optical disk other than a standard circular optical disk is used, the center position of the actual optical disk A large deviation may occur between the determined center position and the method of scanning the disk tray 111 is determined as the actual center position of the optical disk due to variations in the position and size of the opening of the optical disk. Although a slight deviation may occur between the center position and the center position, a relatively accurate center position can be determined even when a deformed optical disk other than the standard circular optical disk is used. Both methods have advantages and disadvantages.

  However, in optical disc label printing, if there is a slight deviation in the determined center position of the optical disc, the deviation appears twice in the label printing result.

  FIG. 17 is a plan view showing an example of the relationship between the determined deviation of the center position of the optical disc and the deviation of the label printing result.

  In this example, it is assumed that label printing is performed with a margin of 0.5 mm across the entire periphery of the label surface of the optical disk. Therefore, when the center position of the actual optical disc completely coincides with the determined center location of the optical disc and the deviation of the center location is 0 mm (X), the margin of the peripheral edge of the label surface in any part of the optical disc The width is 0.5 mm.

  However, for example, when the center position of the actual optical disk and the determined center position of the optical disk deviate by 0.1 mm in either direction (Y), the margin width at the periphery of the label surface of the optical disk is maximum. 0.6 mm, minimum 0.4 mm. Furthermore, when the center position of the actual optical disk and the determined center position of the optical disk are shifted by 0.3 mm in either direction (Z), the margin width at the periphery of the label surface of the optical disk is a maximum of 0. 8 mm, minimum 0.2 mm.

  That is, in optical disc label printing, the discrepancy between the determined center position of the optical disc and the actual optical disc center position is twice as large in the printed label, which is very noticeable visually. Determination of the center position of is required to be performed more accurately.

  Therefore, the optical recording medium center position determining apparatus, center position determining method, and printing apparatus according to the present invention take advantage of both the method of directly scanning the optical disk and the method of scanning the disk tray, and eliminate the disadvantages. Depending on the configuration, the center position of the optical disk as the label printing target is determined.

  Specifically, both the center position of the optical disk based on direct scanning of the optical disk and the center position of the disk mounting portion based on scanning of the disk tray are calculated, and the center position of the optical disk and the center position of the disk mounting portion are calculated. And the center position of the optical disk calculated based on the direct scanning of the optical disk is determined as the center position of the optical disk when the center distance is less than a predetermined reference value. When the center-to-center distance is equal to or greater than a predetermined reference value, the center position of the disk mounting portion calculated based on the scanning of the disk tray is determined as the center position of the optical disk.

  The optical disk center position determination based on the direct scanning of the optical disk can usually determine the optical disk center position more accurately than the optical disk center position determination based on the disk tray scanning, while characters on a part of the label surface, When an optical disk on which figures or the like are printed in advance is used, or when a deformed optical disk other than a circular optical disk is used, the center position of the optical disk to be determined deviates greatly from the actual center position of the optical disk, and the disk tray In many cases, the accuracy is lower than the determination of the center position of the optical disk based on the scanning.

  Therefore, in the optical recording medium center position determining apparatus, the center position determining method, and the printing apparatus according to the present invention, as described above, the center position of the optical disk calculated by the two methods and the center of the disk mounting portion are calculated. When the center-to-center distance is calculated and the center-to-center distance is less than a predetermined reference value, the center position of the optical disk calculated based on the direct scanning of the optical disk is employed, and the center-to-center distance is When the value is equal to or greater than a predetermined reference value, the center position of the disk mounting portion calculated based on the scanning of the disk tray is adopted as the center position of the optical disk.

  As described above, by selectively adopting the center position of the optical disk calculated by the two methods, the center position of the optical disk can be determined more accurately and accurately.

  Hereinafter, an example of a specific process for determining the center position of the optical disc by the center position determining apparatus, the center position determining method, and the printing apparatus of the optical recording medium according to the present invention will be described.

  FIG. 18 is an explanatory view schematically showing an example of a scanning process of the optical disk and the disk tray by the printing apparatus according to the center position determining apparatus and the center position determining method of the optical recording medium according to the present invention.

  In the optical recording medium center position determination apparatus, the center position determination method, and the printing apparatus according to the present invention, the determination of the center position of the optical disk based on the direct scanning of the optical disk and the determination of the center position of the optical disk based on the scanning of the disk tray. Since both are performed, the disc tray on which the optical disc as the label printing target is placed uses the disc tray shown in FIG. 16 as an example, that is, the disc tray 111 provided with two sets (four pieces) of position indicators. Then, scanning with an optical sensor is performed in a state where, for example, the optical disk 81 is mounted on the disk mounting portion 111a.

  First, the path (1) including the scanning line in the sub-scanning direction is scanned to detect the Y coordinate TY1 of the third position indicator 111Y1.

  Next, the path (2) including the scanning line in the main scanning direction is scanned to detect the X coordinates TX1 and TX2 of the first position mark 111X1 and the second position mark 111X2.

  Further, the path (3) including the scanning line in the sub scanning direction is scanned, and the Y coordinates MY1, MY2 and the fourth position indicator 111Y2 of the one end and the other end of the optical disk positioned on the scanning line are displayed. The Y coordinate TY2 is detected.

  Finally, the path (4) including the scanning line in the main scanning direction is scanned to detect the X coordinates MX1 and MX2 of the one end and the other end of the optical disk positioned on the scanning line, respectively.

  Note that the above-described scanning order is an example, and the order of scanning is arbitrary as long as the four positions of the optical disk and the four position markers on the disk tray can be detected. The scanning by the optical sensor 41 along the main scanning direction scanning line is performed by driving the carriage on which the optical sensor 41 is mounted in the main scanning direction, and the optical sensor along the sub scanning direction scanning line. In the scanning by 41, the carriage on which the optical sensor 41 is mounted is stopped at a position within the range of the X coordinate corresponding to the width of the third position indicator 111Y1 and the fourth position indicator 111Y2 in the main scanning direction, and printing is performed. This is performed by moving the disc tray 110 in the sub-scanning direction, that is, in the print medium conveyance direction by the print medium conveyance mechanism of the apparatus.

  If the optical sensor detects the coordinates of the four positions of the optical disk and the four position indicators of the disk tray, the calculation of the center position of the optical disk based on the coordinates of the four positions of the optical disk and the coordinates of the four position marks of the disk tray Based on this, the center position of the disk mounting portion 111a is calculated.

  First, the X coordinate MX = (MX1 + MX2) / 2 of the center position of the optical disc 81 is sub-scanned from the X coordinates MX1, MX2 of the one end and the other end of the optical disc 81 located on the scanning line in the main scanning direction. The Y coordinate MY = (MY1 + MY2) / 2 of the center position of the optical disc 81 is calculated from the Y coordinates MY1 and MY2 of the one end and the other end of the optical disc 81 located on the direction scanning line, respectively. The center position (MX, MY) = ((MX1 + MX2) / 2, (MY1 + MY2) / 2) of the optical disk based on direct scanning is calculated.

  On the other hand, from the X coordinates TX1, TX2 of the first position mark 111X1 and the second position mark 111X2 of the disk tray 111 located on the scanning line in the main scanning direction, the X coordinate TX = ( TX1 + TX2) / 2 is determined from the Y coordinates TY1, TY2 of the third position indicator 111Y1 and the fourth position indicator 111Y2 of the disc tray 111 located on the scanning line in the sub-scanning direction. Coordinates TY = (TY1 + TY2) / 2 are calculated, and the center position (TX, TY) = ((TX1 + TX2) / 2, (TY1 + TY2) / 2) of the disk mounting portion 111a based on the scanning of the disk tray 111 is calculated. To do.

  The calculation order of the center position (MX, MY) of the optical disk based on the direct scanning of the optical disk and the center position (TX, TY) of the disk mounting portion 111a based on the scanning of the disk tray 111 is arbitrary.

After calculating the center position (MX, MY) of the optical disk based on direct scanning of the optical disk and the center position (TX, TY) of the disk mounting portion 111a based on scanning of the disk tray 111, the distance between these two center positions is calculated. Center distance D = ((MX−TX) ² + (MY−TY) ² ) ^1/2 is calculated.

  Then, the calculated center distance D is compared with a predetermined reference value Dref. When the center distance D is less than the reference value Dref (D <Dref), the center position of the optical disk based on the direct scanning of the optical disk (D <Dref). MX, MY) is determined as the center position of the optical disc, and when the center-to-center distance D is equal to or greater than the reference value Dref (D ≧ Dref), the center position of the disc mounting portion 111a based on the scanning of the disc tray 111 ( (TX, TY) is determined as the center position of the optical disk.

  Although the value of the predetermined reference value Dref is arbitrary, when the optical disk is a circular optical disk, a distance corresponding to the maximum error between the center position of the optical disk calculated based on direct scanning of the optical disk and the actual center position of the optical disk; Equivalent values are recommended. If the calculated center-to-center distance D is a value greater than that, the optical disk placed on the disk placement portion 111a of the disk tray 111 is pre-printed with characters, figures, etc. on part of the label surface. In addition, there is a high possibility that the optical disk is a deformed optical disk other than a circular optical disk, and the center position (TX, This is because it is estimated that (TY) is closer to the actual center position of the optical disc.

  The specific value of the predetermined reference value Dref may be a value in the range of 0.4 mm to 0.5 mm, such as 0.5 mm, 3/180 inch≈0.4 mm, for example.

  Note that the operation of the center position determining apparatus, center position determining method, and printing apparatus of the optical recording medium according to the present invention is controlled by a system controller 54 as a control apparatus, and necessary calculations are performed.

  As described above, in the optical recording medium center position determining apparatus, the center position determining method, and the printing apparatus according to the present invention, the center position (MX, MY) of the optical disk and the scanning of the disk tray 111 based on the direct scanning of the optical disk. The center position (TX, TY) of the disk mounting portion 111a based on the above is calculated, and one of the coordinates estimated to be close to the center position of the actual optical disk is adopted as the center position of the optical disk. Therefore, the center position of the optical disc can be determined more accurately and with high accuracy.

  In the above embodiment of the optical recording medium center position determining apparatus, center position determining method, and printing apparatus according to the present invention, the disc tray 111 having the first to fourth position indicators 111X1, 111X2, 111Y1, and 111Y2. However, as long as the position mark is arranged in association with the center position of the disk mounting portion and can be detected by optical scanning, any position mark can be adopted.

  The arrangement of the position markers is not limited to the arrangement of the four first to fourth position markers 111X1, 111X2, 111Y1, and 111Y2. For example, the X coordinate (main scanning direction coordinate) of the center position of the disk mounting portion. , Two position indicators indicating Y coordinates (sub-scanning direction coordinates) may be arranged on the main scanning direction scanning line and the sub-scanning direction scanning line, respectively. When such two position indicators are arranged, the main scanning direction scanning line and the sub-scanning direction scanning line passing over the two position indicators are scanned by the optical sensor, so that the disc is immediately loaded. The center position of the part can be detected and specified.

  Also, as the form of the position mark, a position mark made of paint applied to a predetermined position on the disk tray, a position mark made of a small piece member fixed to a predetermined position on the disk tray, and an opening opened to a predetermined position on the disk tray Arbitrary forms such as a position marker made up of parts can be adopted.

  The optical recording medium center position determining apparatus, the center position determining method, and the printing apparatus according to the present invention are not limited to inkjet printers, and are capable of label printing of optical disks such as CD-R and DVD-R as optical recording media. In general, the present invention can be applied to a center position determining apparatus and a center position determining method for determining the center position of an optical recording medium, and a printing apparatus including such a center position determining apparatus. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating a schematic configuration of a main part in an inkjet printer that is a main application target of a configuration of a printing operation state determination system, a printing operation state determination method, an optical sensor adjustment system, and an optical sensor adjustment method according to the present invention. . 3 is a perspective view showing the arrangement of nozzles and optical sensors 41 when the print head is viewed from above. FIG. 2 is a block diagram illustrating an electrical configuration of a printer 20. FIG. It is explanatory drawing which shows typically the normal structure of the optical sensor for printing operation state determination. It is explanatory drawing which shows typically an example of the pattern for a test | inspection printed and formed with the ink of one color. It is explanatory drawing which shows typically the printing block BL for a test | inspection which comprises the pattern for a test | inspection. It is explanatory drawing which shows typically the locus | trajectory of the spot on the pattern for a test | inspection at the time of the scanning by an optical sensor. It is a graph which shows the relationship between the output signal level and determination threshold value in determination of the presence or absence of ink discharge. It is a graph which shows the relationship between the light reception output signal waveform of an optical sensor, and a determination threshold value. It is a top view which shows the form of a standard optical disk. 2A and 2B are a plan view and a cross-sectional view showing a structure of a disc tray on which an optical disc is placed. It is a perspective view which shows an example of the mode at the time of inserting the optical disk mounted in the disk tray in a printing apparatus, and performing label printing. It is the graph (a) which shows the sensor light reception output when it detects by directly scanning the optical disk with an optical sensor, and the side sectional view (b) which shows the mode. It is explanatory drawing which shows typically the process of determining the center of an optical disk. It is a top view which shows the example of the form of a deformed optical disk. It is a top view which shows the structure of the disc tray used in the center position determination apparatus and center position determination method which determine the center position of an optical disk by the scanning of a disk tray. It is a top view which shows an example of the relationship between the shift | offset | difference of the center position of the determined optical disk, and the shift | offset | difference of a label printing result. FIG. 3 is an explanatory diagram schematically illustrating an example of a scanning process of an optical disc and a disc tray by a printing apparatus and a center position determination device and a center position determination method of an optical recording medium according to the present invention.

Explanation of symbols

10 Irradiation area (spot)
20 Printer 22 Paper stacker 24 Paper feed roller (conveyance roller)
25 Rotary encoder 26 Platen plate 28 Carriage 29 Linear encoder 30 Carriage motor 31 Carriage motor 32 Traction belt 33 Code plate 34 Guide rail 36 Print head 41 Optical sensor 41a Light emitting part 41b Light receiving part 50 Reception buffer memory 52 Image buffer 54 System controller 54a Determination Unit 61 Main scanning driver 62 Sub scanning driver 63 Optical sensor driver 66 Head driver 71 Print pattern 81 Optical recording medium (optical disk)
81a Optical disk opening 82 Single size optical disk 83 Business card size approximately rectangular optical disk 84 Elliptical optical disk 100 Host computer 110 Disk tray 110a, 110b Disk loading section 111 Disk tray 111a, 111b Disk loading section 111X1, 111X2, 111Y1, 111Y2 Position Mark 120 Printer main body 200 Cleaning mechanism 210 Head cap BL Printing block BLa Blank printing block BLb Normal printing block CD Dark cyan ink nozzle row CL Light cyan ink nozzle row KD Black ink nozzle row KL Light black ink nozzle row KP Photo black ink nozzle row MD Dark magenta ink nozzle row ML Light magenta ink nozzle row YD Yellow ink nozzle row La Projected light Lb Reflected light M Output signal level of the output signal level VL normal printing blocks in the main scanning direction P printing paper SS sub-scanning direction Vth determination threshold V0 blank printing block (peak of the light reception output signal)

Claims (10)

A first scanning in a main scanning direction perpendicular to a printing medium conveyance direction of the printing apparatus, having a disk mounting portion formed as a concave portion for mounting an optical recording medium to be subjected to label printing by the printing apparatus; A vertical bisector that is located on a line and that is detectable by optical scanning and that is a line segment connecting the first and second position markers in the main scanning direction. Is positioned on the second scanning line in the sub-scanning direction parallel to the print medium conveyance direction, and the first and second position indicators arranged so as to pass through the center of the disk mounting portion. The third and fourth position markers that can be detected by optical scanning, and a perpendicular bisector connecting the third and fourth position markers in the sub-scanning direction is placed on the disk. The third portion disposed so as to pass through the center of the portion. A disc tray and a fourth position indicator Beauty,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. An optical sensor having a light receiving portion to
The surface of the optical recording medium mounted on the disk mounting portion is scanned by the optical sensor along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction, and the third sensor is scanned. A vertical bisector of the third scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium positioned on the scanning line and the fourth scanning A vertical bisector of the fourth scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium located on the line. The center position is specified, and the first and second position indicators are scanned by the optical sensor along the first scanning line and the second scanning line in the main scanning direction and the sub scanning direction. And the third and fourth position indicators From the vertical bisector between the first and second position markers identified from the mark and the vertical bisector between the third and fourth position markers, the disc tray Based on the result of specifying the center position, the center distance between the optical recording medium and the center position of the disc tray is calculated, the center distance is compared with a predetermined reference value, and the center distance is When the value is less than a reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the center-to-center distance is greater than or equal to the reference value, the disc mounting A controller for determining the center position of the unit as the center position of the optical recording medium;
An apparatus for determining the center position of an optical recording medium, comprising:   The predetermined reference value includes a center position of the optical recording medium specified based on a scanning result by the optical sensor and an actual center position of the optical recording medium when the optical recording medium is a circular optical disk. The center position determining apparatus for an optical recording medium according to claim 1, wherein the distance is equivalent to a distance corresponding to a maximum error of the optical recording medium.   3. The optical recording medium center position determining apparatus according to claim 2, wherein the predetermined reference value is a value in a range of 0.4 mm to 0.5 mm. A first scanning in a main scanning direction perpendicular to a printing medium conveyance direction of the printing apparatus, having a disk mounting portion formed as a concave portion for mounting an optical recording medium to be subjected to label printing by the printing apparatus; A vertical bisector that is located on a line and that is detectable by optical scanning and that is a line segment connecting the first and second position markers in the main scanning direction. Is positioned on the second scanning line in the sub-scanning direction parallel to the print medium conveyance direction, and the first and second position indicators arranged so as to pass through the center of the disk mounting portion. The third and fourth position markers that can be detected by optical scanning, and a perpendicular bisector connecting the third and fourth position markers in the sub-scanning direction is placed on the disk. The third portion disposed so as to pass through the center of the portion. A step of placing the optical recording medium to the disk loading portion of the disc tray and a position indicator for beauty 4,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. The surface of the optical recording medium placed on the disk placing portion is scanned along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction by an optical sensor having a light receiving portion that performs Then, the perpendicular bisector of the third scanning line between the two coordinates specified from the coordinates of the one end and the other end of the optical recording medium positioned on the third scanning line And the perpendicular bisector of the fourth scanning line between the coordinates specified from the coordinates of the one end and the other end of the optical recording medium located on the fourth scanning line Specifying the center position of the optical recording medium, and A disk tray is scanned by the optical sensor along the first and second scanning lines in the main scanning direction and the sub-scanning direction, and the first and second position indicators and the third and fourth positions are scanned. From the vertical bisector between the first and second position markers specified from the coordinates of the marker and the vertical bisector between the third and fourth position markers, the disc The process of identifying the center of the tray,
A center-to-center distance between the optical recording medium and the center position of the disc tray each specified based on a scanning result by the optical sensor is calculated, and the center-to-center distance is compared with a predetermined reference value. When the distance is less than the reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the distance between the centers is equal to or greater than the reference value, A process of determining the center position of the disk mounting portion as the center position of the optical recording medium;
A method for determining the center position of an optical recording medium.   The predetermined reference value includes a center position of the optical recording medium specified based on a scanning result by the optical sensor and an actual center position of the optical recording medium when the optical recording medium is a circular optical disk. 5. The method for determining the center position of an optical recording medium according to claim 4, wherein the distance is equivalent to a distance corresponding to a maximum error of the optical recording medium.   6. The method of determining a center position of an optical recording medium according to claim 5, wherein the predetermined reference value is a value in a range of 0.4 mm to 0.5 mm. A print medium transport mechanism for transporting the print medium;
A print head on which a plurality of ink discharge portions for discharging ink are formed;
On the first scanning line in the main scanning direction perpendicular to the printing medium conveyance direction, and having a disk mounting portion formed as a concave portion for mounting the optical recording medium as the printing medium to be subjected to label printing The first and second position markers that can be detected by optical scanning, and the perpendicular bisector connecting the first and second position markers in the main scanning direction is the first and second position markers. The first and second position markers disposed so as to pass through the center of the disk mounting portion, and an optical element positioned on a second scanning line in the sub-scanning direction parallel to the print medium conveyance direction And a perpendicular bisector connecting the third and fourth position indicators in the sub-scanning direction is a third half and a fourth position indicator that can be detected by the formula scanning. The third and fourth are arranged to pass through the center. A disc tray and a position indicator, and the disc tray conveyed by the printing medium conveying mechanism with mounted on the disk mounting portion said optical recording medium,
A light emitting unit that emits irradiating light to the scanning object, and reflected light reflected on the surface of the scanning object is received and detected, and a light reception output signal having a value corresponding to the intensity of the reflected light is converted and generated. An optical sensor having a light receiving portion to
A carriage mounted with the print head and the optical sensor and driven in the main scanning direction on the print medium;
The surface of the optical recording medium mounted on the disk mounting portion is scanned by the optical sensor along the third and fourth scanning lines in the main scanning direction and the sub-scanning direction, and the third sensor is scanned. A vertical bisector of the third scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium positioned on the scanning line and the fourth scanning A vertical bisector of the fourth scanning line between the coordinates specified from the coordinates of one end and the other end of the optical recording medium located on the line. The center position is specified, and the first and second position indicators are scanned by the optical sensor along the first scanning line and the second scanning line in the main scanning direction and the sub scanning direction. And the third and fourth position indicators From the vertical bisector between the first and second position markers identified from the mark and the vertical bisector between the third and fourth position markers, the disc tray Based on the result of specifying the center position, the center distance between the optical recording medium and the center position of the disc tray is calculated, the center distance is compared with a predetermined reference value, and the center distance is When the value is less than a reference value, the center position of the optical recording medium is determined as the center position of the optical recording medium, and when the center-to-center distance is greater than or equal to the reference value, the disc mounting A controller for determining the center position of the unit as the center position of the optical recording medium;
A printing apparatus comprising:   The predetermined reference value includes a center position of the optical recording medium specified based on a scanning result by the optical sensor and an actual center position of the optical recording medium when the optical recording medium is a circular optical disk. The printing apparatus according to claim 7, wherein the printing apparatus has a value equivalent to a distance corresponding to the maximum error.   The printing apparatus according to claim 8, wherein the predetermined reference value is a value in a range of 0.4 mm to 0.5 mm.   The scanning in the main scanning direction by the optical sensor is performed by the driving operation of the carriage, and the scanning in the sub scanning direction parallel to the printing medium conveyance direction by the optical sensor is performed by the disk tray by the printing medium conveyance mechanism. The printing apparatus according to claim 7, wherein the printing apparatus performs the conveyance operation.

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