JP2011075439A - Printed matter inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for magnetically inspecting large printed matter at a high speed. <P>SOLUTION: In the printed matter inspecting apparatus, a head unit in which a plurality of magnetic heads are arranged along the axial direction of mounting between rollers of a traveling mechanism is used to control the head unit, in such a way as to move in the traveling direction of the traveling mechanism with the rollers of the traveling mechanism in contact with the large printed matter, and to control the head unit in such a way as to move in a prescribed direction over a plane, in parallel with the large printed matter with the rollers of the traveling mechanism out of contact with the large printed matter, so that the large printed matter is inspected magnetically, on the basis of signal values acquired by the magnetic heads. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed matter inspection apparatus that inspects a large-sized printed matter in which basic unit printing original images are regularly arranged with a blank portion interposed therebetween, and in particular, a printed matter that can perform magnetic inspection of a large-sized printed matter at high speed. It relates to an inspection device.

  2. Description of the Related Art Conventionally, there has been known a printed matter inspection apparatus that inspects a printed matter (hereinafter, referred to as “large format printed matter”) in which a basic print original image is regularly arranged with a blank portion interposed therebetween. For example, Patent Document 1 discloses a printed matter inspection apparatus that detects magnetic characteristics of ink from large-size printed matter that has not been dried with ink.

  In the printed matter inspection apparatus of Patent Document 1, in order to prevent the magnetic head from coming into contact with an undried large-format printed matter, the distance between the magnetic head provided on the large-sized printed matter side of the head unit and the large-sized printed matter is set to a small distance. The large-format printed material is scanned while maintaining the same.

  Further, in the printed matter inspection apparatus disclosed in Patent Document 1, air is blown from the detection surface of the magnetic head toward the large printed matter, thereby correcting the waviness and wrinkles of the large printed matter, and the magnetic head contacting the undried large printed matter. Is preventing.

Japanese Patent No. 4228038

  However, the printed matter inspection apparatus of Patent Document 1 has a problem that it takes a long time to inspect the entire large-sized printed matter.

  Specifically, in the printed matter inspection apparatus of Patent Document 1, since there is one magnetic head built in the head unit, in order to inspect the entire large format printed matter, the entire large format printed matter is scanned with one magnetic head. There was a need. For this reason, the total scanning distance of the head unit becomes long, resulting in a long inspection time.

  Further, when a method of blowing air from the detection surface of the magnetic head toward the large format printed matter, a measurement error of the magnetic head due to a temperature change caused by air blowing becomes a problem. For this reason, conventionally, scanning by the head unit is started after the temperature change of the magnetic head due to the air ejection reaches a thermal equilibrium state, and the time required for the inspection of the entire large-sized printed matter is increased.

  For these reasons, how to realize a printed matter inspection apparatus capable of performing magnetic inspection of large-sized printed matter at a high speed is a major issue. Such a problem is not limited to large-format prints, and is a problem that occurs in the same manner when the entire undried prints are inspected.

  The present invention has been made in order to solve the above-described problems caused by the prior art, and an object of the present invention is to provide a printed matter inspection apparatus capable of performing a magnetic inspection of a large-sized printed matter at high speed.

  In order to solve the above-described problems and achieve the object, the present invention is a printed matter inspection apparatus for inspecting large-sized printed matter in which basic print original images are regularly arranged with a blank portion interposed therebetween. A magnetic head having a mechanism for blowing air to the large-sized printed material; and a traveling mechanism provided with intervals at which a plurality of rollers that roll around an attachment shaft travel on the margin portion that sandwiches the printing original image; A head unit having the traveling mechanism and a plurality of the magnetic heads arranged in the direction of the mounting shaft between the rollers of the traveling mechanism; and the head in a state where the rollers of the traveling mechanism are in contact with the large-sized printed matter. Control is performed to move the unit in the traveling direction of the traveling mechanism, and the head unit is moved to the large-sized mark in a state where the rollers of the traveling mechanism do not contact the large-sized printed matter. A movement control means for performing movement control in a predetermined direction on a surface parallel to the object, and a magnetic inspection means for performing a magnetic inspection of the large-sized printed material based on a signal value acquired by the magnetic head. And

  Further, according to the present invention, in the above invention, the magnetic head has an insensitive area against magnetism in an outer peripheral area on the surface on the large-sized printed material side, and the head unit has the insensitive area when viewed from the traveling direction. A plurality of the magnetic heads are arranged in a staggered manner so as not to exist.

  In the present invention, the head unit further includes a magnetic head moving mechanism that moves the magnetic head parallel to the mounting axis direction while maintaining a relative distance between the plurality of magnetic heads. The movement control means controls movement of the magnetic head by the magnetic head moving mechanism.

  According to the present invention, in the above invention, the magnetic inspection unit includes a storage instructing unit for instructing the storage unit to store the signal value for each magnetic head, and a portion where no magnetic detection is performed from the large format printed matter. Extraction means for extracting the corresponding magnetismless signal value from the signal value for each of the magnetic heads stored in the storage unit, and an approximate curve representing the fluctuation history of the magnetismless signal value extracted by the extraction means Calculation means for calculating for each magnetic head, and correction means for correcting the signal value for each magnetic head stored in the storage unit based on the approximate curve calculated for each magnetic head by the calculation means. And further comprising.

  In the present invention, the plurality of magnetic heads are excited by in-phase signals generated by a single oscillator.

  Further, the present invention is characterized in that in the above invention, a plurality of the head units are arranged.

  According to the present invention, a magnetic head having a mechanism for blowing air to a large-sized printed material and a traveling mechanism in which a plurality of rollers that roll around an attachment shaft travel on a blank portion that sandwiches a printing original image. And a head unit in which a plurality of magnetic heads are arranged in the mounting axis direction between the rollers of the traveling mechanism, and control for moving the head unit in the traveling direction of the traveling mechanism in a state where the rollers of the traveling mechanism are in contact with the large format printed matter. And controlling the movement of the head unit in a predetermined direction on a plane parallel to the large-sized printed material while the roller of the traveling mechanism is not in contact with the large-sized printed material, and the magnetic of the large-sized printed material based on the signal value acquired by the magnetic head. Since the inspection is performed, the large-sized printed matter can be obtained by increasing the area of the area that can be detected by one scan by the head unit. An effect that it is possible to shorten the time required for the inspection of the body.

  Further, according to the present invention, the magnetic head has a magnetic insensitive region in the outer peripheral region on the surface of the large size printed matter, and the head unit includes a plurality of the magnetic heads so that there is no insensitive region when viewed from the running direction. Since the staggered arrangement is provided, there is an effect that it is possible to eliminate the scanning leakage area due to the insensitive area. Further, if the magnetic head is arranged so as to be movable corresponding to an arbitrary area, it is possible to perform scanning while avoiding an area that does not require measurement.

  According to the invention, the head unit further includes a magnetic head moving mechanism that moves the magnetic head in parallel with the mounting axis direction while maintaining a relative distance between the plurality of magnetic heads. Since the movement of the magnetic head is controlled, the large-sized printed matter can be inspected without moving the head unit in the direction orthogonal to the traveling direction.

  In addition, according to the present invention, an instruction to store a signal value for each magnetic head in the storage unit is given, and a magneticless signal value corresponding to a portion where there is no magnetic detection from the large-format printed matter is stored for each magnetic head stored in the storage unit. The magnetic head is extracted from each of the signal values, and an approximate curve representing the fluctuation history of the extracted signal value without magnetism is calculated for each magnetic head, and the magnetic head stored in the storage unit based on the approximate curve calculated for each magnetic head The signal value for each magnetic head is corrected for each magnetic head even if there is a different temperature change for each magnetic head in the interval from the start of scanning to the end of scanning. There is an effect that can be obtained.

  Further, according to the present invention, since the plurality of magnetic heads are excited by the in-phase signal generated by the single oscillator, the influence of the magnetic flux generated by the predetermined magnetic head is applied to the other magnetic heads. By preventing this, the magnetic head can be arranged adjacently.

  Further, according to the present invention, since a plurality of head units are arranged, the time required for the inspection of the entire large-sized printed matter can be shortened by increasing the area of the region that can be detected by one scan. There is an effect that can be.

FIG. 1 is a diagram showing an outline of a printed matter inspection method according to the present invention. FIG. 2 is an external view of the printed matter inspection apparatus according to the present embodiment. FIG. 3 is a block diagram illustrating the configuration of the printed matter inspection apparatus according to the present embodiment. FIG. 4 is a diagram illustrating a magnetic head and a circuit related to the magnetic head. FIG. 5 is a diagram showing the configuration of a head unit in which the magnetic head is fixed. FIG. 6 is a diagram showing a configuration of a head unit in which the magnetic head is movable. FIG. 7 is a diagram showing a procedure for correcting the signal value acquired by the magnetic head. FIG. 8 is a flowchart illustrating a processing procedure executed by the printed matter inspection apparatus. FIG. 9 is a diagram illustrating an example of a large-sized printed material. FIG. 10 is a diagram illustrating a printing unit inspection apparatus including a plurality of head units.

  Exemplary embodiments of a printed matter inspection method according to the present invention will be described below in detail with reference to the accompanying drawings. In the following, a description will be given of a case where the printed matter inspection apparatus to which the printed matter inspection method according to the present invention is applied targets a large format printed matter. Can do.

  In the following, the outline of the printed matter inspection method according to the present invention will be described with reference to FIGS. 1 and 9, and then an embodiment of the printed matter inspection apparatus to which the printed matter inspection method according to the present invention is applied will be described with reference to FIGS. This will be described using.

  First, an outline of the printed matter inspection method according to the present invention will be described. FIG. 1 is a diagram showing an outline of a printed matter inspection method according to the present invention. In the figure, only a part of the printed matter inspection apparatus 10 to which the printed matter inspection method according to the present invention is applied is shown. Also, (A) in the figure shows an overhead view of the printed matter inspection apparatus 10, (B) in the figure shows a view of the head unit 11 viewed from the large-sized printed matter 100 side, and (C) in the same figure. FIG. 4 shows views of the head unit 11 as seen from the positive direction of the Y axis.

  As shown in FIGS. 1A and 1B, the printed matter inspection method according to the present invention has one feature in that a large-size printed matter 100 is magnetically inspected using a head unit 11 having a plurality of magnetic heads 11a. There are features. Further, the head unit 11 includes a pair of rollers 11b that rolls with a mounting axis in a direction perpendicular to the traveling direction 200 of the head unit 11, that is, a direction parallel to the Y axis in FIG. Is provided.

  When magnetic inspection is performed, the roller 11b travels on a blank portion (portion where there is no ink) of the large-sized printed matter, so that a minute gap (for example, 150 μm) between the lower surface of the magnetic head 11a and the large-sized printed matter 100 is provided. Hold.

  The head unit 11 is connected to the X-axis movable part 3a via the Z-axis movable part 2c which can be moved in the direction 5c (the positive and negative directions of the Z-axis in the figure) by the Z-axis drive motor 1c. Has been.

  The X-axis movable part 3a is controlled to move on the X-axis guide 2a in the direction 5a (the positive and negative directions of the X-axis in the figure) by the X-axis drive motor 1a. The X-axis guide 2a is connected to the Y-axis movable part 3b, and the Y-axis movable part 3b is moved on the Y-axis guide 2b in the direction 5b by the Y-axis drive motor 1b (see FIG. The movement is controlled in the positive and negative directions of the Y axis.

  That is, the head unit 11 is provided so as to be movable along the X axis, the Y axis, and the Z axis shown in FIG. For example, when scanning the large format printed matter 100 in the traveling direction 200 shown in the figure, the Y coordinate is fixed and the head unit 11 is moved until the roller 11b comes into contact with the large format printed matter 100 at the X coordinate scanning start position. Lower. Then, the head unit 11 is caused to travel in the traveling direction 200 by changing only the X coordinate.

  Subsequently, when the scanning end position of the X coordinate is reached, the head unit 11 is lifted to separate the roller 11b from the large size printed matter 100. Then, the X coordinate is returned to the travel start position while changing the Y coordinate of the head unit 11, the head unit 11 is lowered, and the next scanning is started.

  Here, the large-sized printed material 100 to be inspected will be described with reference to FIG. FIG. 9 is a diagram illustrating an example of the large-sized printed material 100. The figure shows a large-format printed material 100 on which a total of 20 (4 × 5) printing original images 101 are printed, with four columns from A to D in the X direction and five rows from 1 to 5 in the Y direction. ing. In addition, a blank portion where no ink is printed is provided between the outer peripheral portion of the large format printing unit 100 and each print original 101.

  Then, as described above, when scanning in the X direction, for example, the head unit 11 is lowered at the left end of the first row in the figure to start scanning of the first row and to the right end of the first row. When the scanning is completed, the head unit 11 is raised. If a mechanism for shifting the position of the magnetic head 11a in the Y direction is provided in the head unit 11, the scanning of the first row is performed a plurality of times by repeating the procedure of shifting the magnetic head 11a for scanning. Is also possible. When all the scans of the first row are completed, the head unit 11 is lowered at the left end of the second row while the head unit 11 is raised, and the scan of the second row is started.

  Returning to FIG. 1, description will be made for (B) and after in FIG. 1. As shown in FIG. 1B, when the head unit 11 is viewed from the large-sized printed product 100 side, the plurality of magnetic heads 11a are arranged in a direction orthogonal to the traveling direction 200, that is, in the Y-axis direction in FIG. Yes. Note that variations in the arrangement of the magnetic head 11a will be described later. Further, the magnetic head 11a can be moved in the head unit 11, but this point will also be described later.

  FIG. 1B shows that six holes are provided on the surface of the magnetic head 11a on the large-format printed material 100 side. These holes are used for air blowing to the large-sized printed material 100. It is a spout. The air blown onto the large-sized printed material 100 is compressed air supplied from a compressor (not shown).

  Specifically, as shown in FIG. 1C, the undulations and wrinkles of the large-sized printed material 100 are corrected by blowing air from the ejection port in the direction 300. Thereby, the space | interval of the magnetic head 11a and the large format printed matter 11a can be kept appropriate. In addition, air is guide | induced to a jet nozzle via the flow paths 11c, such as a tube and a pipe.

  As described above, in the printed matter inspection method according to the present invention, a plurality of magnetic heads 11 a arranged in a direction orthogonal to the traveling direction are provided for the head unit 11, and the large-sized printed matter 100 is scanned using the head unit 11. It was decided.

  Therefore, a wider range of magnetic information can be obtained in a single scan than when a single head unit is used. For this reason, the number of scans can be reduced, and the inspection time required for the entire large-sized printed material 100 can be shortened.

  The conventional magnetic inspection apparatus employs a single head unit. When a plurality of AC bias type magnetic heads are provided in the head unit, the magnetic heads are affected by magnetic flux leaking from adjacent magnetic heads. This is because the signal value to be acquired is disturbed and a measurement error occurs.

  For this reason, in the printed matter inspection method according to the present invention, the magnetic head 11a can be adjacently arranged by devising the excitation method of the magnetic head 11a. Details of this point will be described later.

  Further, in the conventional magnetic inspection apparatus, since the scanning by the head unit 11a is started after the temperature change of the magnetic head 11a due to the air ejection is in thermal equilibrium, the time required for the magnetic inspection is accumulated due to accumulation of waiting time. .

  For this reason, in the printed matter inspection method according to the present invention, the above-described waiting time is made unnecessary by performing a predetermined correction process on the signal value acquired by the magnetic head 11a. It will be described later.

  Below, the Example about the printed matter inspection apparatus to which the printed matter inspection method based on this invention demonstrated using FIG. 1 and FIG. 9 is applied is described.

  First, the external appearance of the printed matter inspection apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 2 is an external view of the printed matter inspection apparatus 10 according to the present embodiment. As shown in the figure, the printed matter inspection apparatus 10 is provided with a base plate 21 on which the large-sized printed matter 100 is placed.

  The base plate 21 is made of a non-magnetic material such as glass processed so that the upper surface is flat. And the clamp mechanism 22 and the clamp mechanism 23 which fix the edge | side which large format printed material opposes are provided in the both sides of the base plate 21, respectively.

  That is, when the operator places the large-sized printed material 100 on the base plate 21, the positioning mechanism 24 adjusts the position of the large-sized printed material 100 in the front-rear direction and the rotation angle viewed from above, and the clamping mechanism 22 and the clamping mechanism. 23, the blank portion provided in the outer peripheral portion of the large-sized printed material 100 is fixed while being pulled. As a result, the large-sized printed material 100 is placed at a specified position along the upper surface of the base plate 21.

  Further, the head unit 11 described in FIG. 1 is provided above the base plate 21. The display / operation unit 25 includes a display unit such as a display and an operation unit such as a dial or a button. The display / operation unit 25 inputs an instruction to the printed matter inspection apparatus 10 or displays an inspection result by the printed matter inspection apparatus 10. To do.

  Next, the internal configuration of the printed matter inspection apparatus 10 will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration of the printed matter inspection apparatus 10 according to the present embodiment. In the figure, the case where the head unit 11 includes two magnetic heads 11a is illustrated, but the number of magnetic heads 11a may be three or more. Further, in the same figure, the description of the movable mechanism shown in FIG. 1 is omitted.

  As shown in FIG. 1, the printed matter inspection apparatus 10 includes a head unit 11, a control unit 12, a storage unit 13, and an air compressor 14. The head unit 11 further includes at least two magnetic heads 11a. The control unit 12 includes a movement control unit 12a, a magnetic information storage instruction unit 12b, an approximate curve calculation unit 12c, and a correction processing unit 12d. And a magnetic inspection unit 12e. And the memory | storage part 13 memorize | stores the magnetic information 13a. The compressed air sent out from the air compressor 14 is guided to each magnetic head 11a via a flow path 11c such as a tube or a pipe shown in FIG. 1C (refer to the broken line arrow in the figure).

  The head unit 11 is a unit that holds a plurality of magnetic heads 11a, and based on an instruction from the movement control unit 12a of the control unit 12, the relative position with respect to the large-sized printed material 100 to be inspected is shown in FIG. , Y axis direction and Z axis direction are changed. Similarly, based on an instruction from the movement control unit 12a, the air ejection from the magnetic head 11a is started and stopped. The detailed configuration of the head unit 11 will be described later with reference to FIGS. 5 and 6.

  The magnetic head 11a is an AC bias type magnetic detection head, and includes a detection surface, that is, a detection head provided on the large print 100 side, and a cancel head that is adjacent to the detection head and separated from the large print 100. Composed. Further, an air outlet is provided on the detection surface of the magnetic head 11a.

  Here, the configuration of the magnetic head 11a and the configuration of the head unit 11 will be described with reference to FIGS. FIG. 4 is a diagram showing the magnetic head 11a and a circuit related to the magnetic head 11a. 1A is a bottom view of the magnetic head 11a, FIG. 1B is a side view of the magnetic head 11a, and FIG. 1C is a circuit diagram of the magnetic head 11a. Each figure is shown.

  As shown in FIG. 4A, an air outlet 41 is provided on the lower surface of the magnetic head 11a. In addition, a detection region 42 capable of magnetic detection exists at the center of the lower surface. That is, the area other than the detection area 42 is a magnetic insensitive area.

  Here, the width 43 in the Y-axis direction of the magnetic head 11a is, for example, 16 mm, and the width 42 in the Y-axis direction of the detection region 42 is, for example, 10 mm. In the present embodiment, the case where the magnetic head 11a having the insensitive area on the outer peripheral portion of the detection surface is mainly described. However, the magnetic head 11a having the insensitive area minimized may be used.

  As shown in FIG. 4B, a counter electrode core 45 is provided inside the magnetic head 11a. Further, air is blown in the direction 300 toward the large-sized printed material 100 from the ejection port 41 provided on the lower surface of the magnetic head 11a.

  As shown in FIG. 4C, the plurality of magnetic heads 11a (one for each of 1CH, 2CH, and 3CH in the figure) are excited based on an in-phase AC signal generated by a single oscillator 501. Is done. Thus, by exciting each magnetic head 11a with the in-phase signal, interference between the magnetic heads 11a due to leakage magnetic flux from the adjacent magnetic head 11a can be prevented. Therefore, even when the magnetic head 11a is provided adjacently, highly accurate magnetic detection is possible.

  As shown in the figure, a cancel head 45 a and a detection head 45 b are formed on the counter electrode core 45. Specifically, in the upper block 45aa of the counter electrode core 45, the cancel head primary coil 45ab is wound around the excitation drive circuit 502 side pole, and the cancel head secondary coil 45ac is wound around the amplification circuit 503 side pole. Thus, a cancel head 45a is configured.

  Further, in the lower block 45ba of the counter electrode core 45, the detection head primary coil 45bb is wound around the excitation drive circuit 502 side pole, and the detection head secondary coil 45bc is wound around the amplification circuit 504 side pole. A head 45b is configured. The primary coil 45ab for cancellation head and the primary coil 45bb for detection head wound around the upper block 45aa and the lower block 45ba are connected in series, and the secondary coil 45ac for cancellation head and the secondary coil for detection head are connected. The coil 45bc is connected in parallel.

  The AC reference signal generated by the oscillator 501 is input to the excitation drive circuit 502. The excitation drive circuit 502 adds a predetermined excitation signal to the reference signal and then cancels the primary coil 45ab for the cancel head. And it supplies with electricity to primary coil 45bb for detection heads. Thereby, an alternating magnetic field is generated. The cancel head secondary coil 45ac and the detection head secondary coil 45bc detect a change in an alternating magnetic field due to the approach of a magnetic body or the like.

  Here, the secondary coil 45bc for the detection head detects a change in the alternating magnetic field due to the magnetic ink printed on the large size printed matter 100. However, the secondary coil 45ac for the cancel head is separated from the large size printed matter 100 because it is separated from the large size printed matter 100. Does not detect magnetic field changes.

  Therefore, the difference between the signal obtained by amplifying the output from the cancel head secondary coil 45ac by the amplifier circuit 503 and the signal obtained by amplifying the output from the detection head secondary coil 45bc by the amplifier circuit 504 is the differential amplifier circuit 505. By inputting to, a magnetic signal based on the output of the cancel head 45a can be acquired.

  The output from the cancel head secondary coil 45ac is fed back to the excitation drive circuit 502 via the amplifier circuit 503. This is because the output of the cancel head secondary coil 45ac to be used as a reference is affected by the temperature difference between the channels, the temperature fluctuation of the compressed air supplied from the air compressor 14 with time, and the individual difference of the magnetic head 11a. This is to prevent variation from channel to channel.

  That is, by feeding back the output of the cancel head secondary coil 45ac to the excitation drive circuit in each channel, the output amplitude of the cancel head 45a can always be a predetermined constant value. Thereby, the output amplitude of the cancel head 45a can be made the same over all the channels.

  As described above, since each magnetic head 11a is excited in the same phase based on the AC reference signal generated by the single oscillator 501, the magnetic heads 11a are arranged adjacent to each other. However, the influence of the alternating magnetic field generated by the other magnetic head 11a can be eliminated, and high-precision magnetic detection can be performed.

  In addition, since the output amplitude of the cancel head 45a is made the same over all channels by feeding back the output of the cancel head 45a for each magnetic head 11a, the detection is based on the temperature difference between the magnetic heads 11a and the individual difference of the magnetic head 11a. Variation in values can be prevented.

  Next, the configuration of the head unit 11 will be described with reference to FIGS. FIG. 5 is a diagram showing a configuration of the head unit 11 in which the magnetic head 11a is fixed. 2A shows the case where the magnetic heads 11a having the smallest dead area are arranged, and FIG. 2B shows the case where the magnetic heads 11a having the dead area are arranged in a staggered manner. (C) shows the arrangement variations of the rollers 11b.

  As shown in FIG. 5A, when using the magnetic head 11a having a minimal dead area, the magnetic heads 11a may be arranged adjacent to each other in the Y-axis direction of the head unit 11. In this way, when the head unit 11 is moved in the traveling direction 200 to scan the large size printed matter 100, a wider range of magnetic information can be obtained by one scan.

  Here, the interval 51 between the pair of rollers 11b provided so as to travel in the traveling direction 200 is adjusted to a width that allows each roller 11b to pass on the margin between the printing original images 101 printed on the large-sized printed material 100. ing. The width 52 of each roller 11b is adjusted to be smaller than the width of the margin.

  On the other hand, as shown in FIG. 5B, when the magnetic head 11a having the insensitive area on the outer peripheral portion of the detection surface (see FIG. 4A) is used, the traveling direction 200 When viewed from the side, the magnetic heads 11a are arranged in two rows in a staggered arrangement in the mounting axis direction (Y-axis direction in the figure) so that there is no dead area between the detection areas 42 in the adjacent magnetic heads 11a. And it is sufficient. Thereby, even if each magnetic head 11a has a dead area, the head unit 11 having a continuous detection area 42 can be obtained.

  By doing in this way, even if it is a case where the magnetic head 11a which has a dead area on a detection surface is used, a wider range of magnetic information can be acquired by one scan, without producing a detection omission area.

  5A and 5B show the head unit 11 having one set of rollers 11a, the head unit 11 having a plurality of sets of rollers 11a may be configured. For example, as shown in FIG. 5C, three sets of rollers 11a can be arranged. Thus, if a plurality of sets of rollers 11a are arranged, it is possible to prevent a pitching operation (rotating operation around the Y axis) when the head unit 11 moves in the traveling direction 200.

  Also, as shown in FIG. 5, when a plurality of magnetic heads 11a are fixed in the head unit 11, one line of large-sized printed material (for example, (1, A), ( 1, B), (1, C), and (1, D))), the number of magnetic heads 11a covering the position range to be measured in the Y-axis direction may be provided.

  FIG. 5 shows the case where a plurality of magnetic heads 11a are fixed in the head unit 11. However, the head unit 11 may be configured such that the magnetic head 11a is movable in the Y-axis direction. Therefore, hereinafter, the head unit 11 in which the magnetic head 11a is movable will be described with reference to FIG.

  FIG. 6 is a diagram showing the head unit 11 in which the magnetic head 11a is movable. Note that (A) in the figure shows a case where two magnetic heads 11a arranged at a predetermined interval in the Y-axis direction are moved, and (B) in the figure shows three magnets arranged in a staggered manner. Each of the cases where the head 11a is moved is shown.

  As shown in FIG. 6A, the two magnetic heads 11 a are fixed to the movable portion 52 so that the distance between the detection regions 42 has a predetermined width 51. The movable portion 52 is driven by a motor (not shown) and controlled to move in a direction 53 that is the negative direction of the Y axis and a direction 54 that is the positive direction of the Y axis.

  The motor that drives the movable unit 52 operates in accordance with an instruction from the movement control unit 12a illustrated in FIG. Then, the head unit 11 moves in the traveling direction 200 while fixing the position of the movable portion 52 in the Y-axis direction, and when performing the next scanning, the position of the head unit 11 in the Y-axis direction is fixed, Only the movable part 52 is shifted along the Y axis.

  For example, as shown in (A-1) of FIG. 6, in the first scan for a predetermined printing original image 101, the magnetic information of the area indicated by the oblique lines in FIG. 6 is acquired by the two head units 11a. The Then, when the second scanning is performed by shifting only the movable portion 52 in the positive direction of the Y axis while the position of the head unit 11 in the Y axis direction is fixed, a hatched line in FIG. Magnetic information of the area indicated by is acquired.

  As described above, even when the magnetic head 11a has a dead area, the magnetic information over the entire print original 101 printed on each line of the large format printing unit 100 without changing the position of the head unit 11 in the Y-axis direction. Can be obtained. 6A illustrates the case where two magnetic heads 11a are used, the number of magnetic heads 11a may be three or more.

  As shown in FIG. 6B, the three magnetic heads 11a arranged in a staggered manner are provided in the movable portion 52a of the head unit 11, and the movable portion is the same as in the case shown in FIG. It is also possible to move 52a in the direction 53 or the direction 54. 6B illustrates the case where three magnetic heads 11a are used, the number of magnetic heads 11a can be any number of two or more.

  Returning to the description of FIG. 3, the control unit 12 will be described. The control unit 12 is a processing unit that performs processing such as movement control and air ejection control of the head unit 11, correction processing of magnetic data acquired from the magnetic head 11a, and magnetic inspection processing using the magnetic data after the correction processing.

  The movement control unit 12a is a processing unit that performs movement control of the head unit 11 by instructing the motors (1a, 1b, and 1c) illustrated in FIG. The movement control unit 12a also performs movement control of the movable part (52 or 52a) in the head unit 11 shown in FIG. Note that the movement control unit 12a also issues a blow start instruction or a blow stop instruction for air jetted from each magnetic head 11a supplied with compressed air from the air compressor 14 toward the large-sized printed material 100.

  The magnetic information storage instruction unit 12b is a processing unit that instructs to store the magnetic data acquired by each magnetic head 11a in the storage unit 13 as the magnetic information 13a. The magnetic information 13a stored in the storage unit 13 is used by the approximate curve calculation unit 12c.

  The approximate curve calculation unit 12c is a processing unit that reads the magnetic information 13a stored in the storage unit 13 and performs a process of calculating a base curve corresponding to a non-magnetic portion of the variation curve representing the variation of the time-series signal value. . Specifically, if the temperature of the magnetic head 11a does not change in the scanning section (section from the scanning start position to the scanning end position), the signal value corresponding to the non-magnetized portion should be constant. In this case, the base curve is a straight line parallel to the time axis.

  However, in the case where air is blown from the detection surface of the magnetic head 11a toward the large-sized printed matter, there is usually a difference between the temperature of each magnetic head 11a and the temperature of the ejected air. A predetermined time is required until the temperature change of the magnetic head 11a due to the ejection reaches a thermal equilibrium state. Furthermore, the temperature of the compressed air supplied from the air compressor 14 may change over time due to a temperature rise of the air compressor 14 or the like. Therefore, the shape of the base curve described above is not a straight line. If such a base curve can be obtained, it is possible to obtain a signal value from which the influence of the temperature change is eliminated by performing correction for subtracting the base curve from the fluctuation curve.

  For this reason, the approximate curve calculation unit 12c calculates the base curve as an approximate curve using a multidimensional function. Then, the correction processing unit 12d acquires a correction signal value excluding the influence of the temperature change by subtracting the approximate curve calculated by the approximate curve calculation unit 12c from the fluctuation curve of the magnetic information 13a.

  Subsequently, the magnetic inspection unit 12e performs magnetic inspection by comparing the correction signal value received from the correction processing unit 12d with a reference signal value prepared in advance. The storage unit 13 is a storage unit configured by a storage device such as a hard disk drive or a non-volatile memory, and the magnetic information 13a includes the identifier of the magnetic head 11a, information such as the X and Y coordinates during scanning, and the magnetic head 11a. Is information including the acquired signal value.

  Next, an outline of processing performed by the above approximate curve calculation unit 12c and the correction processing unit 12d will be described with reference to FIG. FIG. 7 is a diagram showing a procedure for correcting the signal value acquired by the magnetic head 11a. In addition, in the same figure, the fluctuation graph of the signal value obtained by scanning each printing original picture 101 in the 1st line of the large format printed matter 100 shown in FIG. 9 is illustrated. Further, in the same figure, for easy understanding of the explanation, a fluctuation graph that varies in a complicated manner corresponding to the magnetic ink pattern is simplified.

  As shown in FIG. 7A, the signal value acquired by the magnetic head 11a varies according to the scanning distance. Here, if magnetism is detected at one location of each print original 101, a peak value 72 as a magnetic signal is obtained for each of the four print originals 101. Each peak value 72 is detected in a state of being added to the base curve 71 corresponding to the non-printed portion.

  Note that a point 73 shown in the figure represents a point where the slope of the base curve 71 becomes 0, that is, a point where the thermal equilibrium state is reached. Conventionally, the head unit 11 waits until such a thermal equilibrium state is reached and scans by the head unit 11. Was done. However, when waiting for the thermal equilibrium state, the time required for magnetic inspection of the entire large-sized printed material 100 is increased. In particular, when a plurality of magnetic heads 11a are provided in the head unit 11, the waiting time of each magnetic head 11a also differs. For this reason, it is necessary to determine the waiting time according to the magnetic head 11a having the longest waiting time, and the time required for the magnetic inspection is likely to increase.

  Therefore, in the printed matter inspection apparatus 10 according to the present embodiment, scanning is performed without waiting for the thermal equilibrium state, and the signal values acquired by the plurality of magnetic heads 11a are corrected for each magnetic head 11a, whereby each magnetic head. It was decided to remove the influence of thermal fluctuation from 11a.

  Specifically, as shown in FIG. 7B, a signal value variation graph is divided into a threshold value L and a threshold value H that is larger than the threshold value L, and a signal that is equal to or higher than the threshold value L and lower than or equal to the threshold value H. Only the value (hereinafter referred to as “extracted signal value”) is extracted. Then, as shown in FIG. 7C, an approximate curve 74 that approximates the fluctuation of the extracted signal value is calculated.

  Here, the approximate curve 74 can be calculated by, for example, regression analysis, and is calculated as a secondary curve to a seventh curve. In terms of accuracy, a quadratic curve is sufficient. Further, the calculated approximate curve 74 corresponds to the base curve 71 shown in FIG.

  The threshold value L and the threshold value H are set in advance so as to include such a fluctuation range by obtaining an average of the fluctuation range of the base curve 71 from an experiment or the like. Further, when calculating the approximate curve 74 based on the extracted signal value, the distribution state of the extracted signal value with respect to the approximate curve 74 once calculated is analyzed, and at both ends of the non-magnetic region sandwiched between the threshold value L and the threshold value H. The approximate curve 74 may be calculated again using only the extracted signal values distributed in the vicinity of the approximate curve 74 after removing the distributed magnetic signal values. In this case, for example, an extracted signal value in a range of ± 1σ or ± 0.5σ can be used for the approximate curve 74. Here, σ represents a standard deviation.

  Then, as shown in FIG. 7C, if the approximate curve 74 is calculated by the approximate curve calculation unit 12c, the correction processing unit 12d calculates the approximate curve from the variation graph shown in FIG. A process of subtracting the value of 74 is performed. Thereby, the signal value from which the influence of the temperature fluctuation is eliminated can be obtained (see FIG. 7D).

  Next, a processing procedure executed by the printed matter inspection apparatus 10 shown in FIG. 3 will be described with reference to FIG. FIG. 8 is a flowchart illustrating a processing procedure executed by the printed matter inspection apparatus. In FIG. 9, the original print 101 group ((n, A), (n, B), (n) in the n-th line (n is 1 to 5 in the case of FIG. 9) of the large-sized printed material 100 shown in FIG. The processing procedure in the case of scanning (n, C) and (n, D)) is shown. Further, in the figure, the processing procedure relating to the start and end of the air ejection is omitted.

  As shown in FIG. 8, the movement control unit 12a positions the head unit 11 on the nth row of the large-sized printed material 100 (step S101). Further, the movement control unit 12a positions each magnetic head 11a to the initial value in the head unit 11 (step S102).

  Subsequently, the printed matter inspection apparatus 10 stores the signal value acquired by the magnetic head 11a in the storage unit 13 while moving the head unit 11 in the X direction (for example, the positive direction of the X axis shown in FIG. 1). (Step S103).

  Then, it is determined whether or not scanning of the last column (in the case of FIG. 9, (n, D)) has been completed (step S104). If scanning of the last column has been completed (step S104, Yes), an approximation is performed. The curve calculation unit 12c calculates an approximate curve of a baseline (see the base curve 71 shown in FIG. 7A) in the signal value variation graph (step S105). In addition, when the determination condition of step S104 is not satisfied (step S104, No), the processing after step S103 is repeated.

  Subsequently, the correction processing unit 12d corrects the signal value with the approximate curve calculated in Step S105 (Step S106), and the magnetic inspection unit 12e performs a magnetic inspection with the corrected signal value (Step S107). Then, it is determined whether or not the magnetic head 11a is at the end position in the head unit 11 (step S108). If it is at the end position (step S108, Yes), the process is ended.

  On the other hand, when the magnetic head 11a is not at the end position in the head unit 11 (step S108, No), after positioning the magnetic head 11a to the next position in the head unit 11 (step S109), the steps after step S103 are performed. Repeat the process.

  In actual operation, the head unit 11 is controlled to move to the scanning start position of the next scanning immediately after the last row (n, D) scanning is completed. The processing of the signal value acquired by is performed in parallel.

  By the way, although the printed matter inspection apparatus 10 provided with the one head unit 11 was demonstrated so far, it is good also as comprising the printed matter inspection apparatus 10 provided with the several head unit 11. FIG. Therefore, hereinafter, the printed matter inspection apparatus 10 including the plurality of head units 11 will be described.

  FIG. 10 is a diagram illustrating a printed matter inspection apparatus 10 including a plurality of head units 11. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals. In the following description, differences from the printed matter inspection apparatus 10 shown in FIG. 1 will be mainly described.

  The printed matter inspection apparatus 10 shown in FIG. 10 is different from FIG. 1 in that a plurality of head units 11 (11A and 11B in the figure) are provided on the X-axis movable portion 3a. Specifically, as shown in FIG. 10, the head unit 11 </ b> A and the head unit 11 </ b> B are arranged at a predetermined interval in the Y-axis direction in the X-axis movable unit 3 a. Thus, by providing a plurality of head units 11, a larger area can be scanned with a smaller number of scans, and magnetic inspection can be performed at high speed.

  As shown in FIG. 10, the head unit 11A and the head unit 11B are independently controlled to move in the Z-axis direction. That is, the head unit 11A is used for the X-axis via the Z-axis movable portion 2c that can be moved in the direction 5c (the positive and negative directions of the Z-axis in the same figure) by the Z-axis drive motor 1c shown in FIG. It is connected to the movable part 3a.

  Further, the head unit 11B is for the X-axis via the Z-axis movable portion 2c that can be moved in the direction 5d (the positive and negative directions of the Z-axis in the same figure) by the Z-axis drive motor 1c shown in FIG. It is connected to the movable part 3a. The X-axis movable portion 3a is controlled to move on the X-axis guide 2a in the direction 5a (the positive and negative directions of the X-axis in the same figure) by the X-axis drive motor 1a. In conjunction with the movement of the movable portion 3b, movement on the Y-axis guide 3aa is controlled in the direction 5b (the positive and negative directions of the Y-axis in the figure).

  Further, the Y-axis guide 3aa for guiding the movement of the X-axis movable part 3a in the Y direction slides in the recesses of the pair of slide rails 6a, thereby moving the slide rail 6a on the direction 5a (shown in the figure). Move in the positive and negative directions of the X axis). In addition, in FIG. 10, although the both-support mechanism which hold | maintains the guide 3aa for Y axes with the one set of slide rail 6a was shown, it is good also as a cantilever mechanism which abbreviate | omitted one slide rail 6a.

  As described above, in the printed matter inspection apparatus 10 shown in FIG. 10, a plurality of head units 11 are provided in parallel and controlled to move independently in the Z-axis direction. Therefore, as a result of moving the X-axis movable part 3a in the Y-axis direction, the head unit 11 protruding from the large-sized printed material 100 can continue to be scanned by other head units 11 without being lowered to the large-sized printed material 100. it can.

  In addition, although FIG. 10 demonstrated the case where the two head units 11 were provided, it is good also as providing the three or more head units 11. FIG. For example, if the head unit 11 is provided for each line of the large-sized printed material 100, all the lines of the large-sized printed material 100 can be inspected at one time by one scan.

  As described above, in this embodiment, after using a head unit in which a plurality of magnetic heads are arranged in the mounting axis direction between the rollers of the traveling mechanism, the rollers of the traveling mechanism are in contact with the large format printed matter. The head unit is controlled to move in the traveling direction of the traveling mechanism, and the head unit is moved in a predetermined direction on a plane parallel to the large-sized printed matter while the rollers of the traveling mechanism are not in contact with the large-sized printed matter. The printed matter inspection apparatus is configured to perform a magnetic inspection of a large-sized printed matter based on the signal value acquired by the head. Therefore, by increasing the area of the region that can be detected by one scan by the head unit, the time required for the inspection of the entire large-sized printed matter can be shortened.

  As described above, the printed matter inspection apparatus according to the present invention is useful for magnetic inspection of large-format printed matter, and is particularly suitable for reducing the time required for magnetic inspection.

DESCRIPTION OF SYMBOLS 10 Printed product inspection apparatus 11 Head unit 11a Magnetic head 11b Roller 11c Flow path 12 Control part 12a Movement control part 12b Magnetic information storage instruction part 12c Approximation curve calculation part 12d Correction processing part 12e Magnetic inspection part 13 Storage part 13a Magnetic information 14 Air compressor

Claims (6)

A printed matter inspection apparatus for inspecting large-format printed matter in which basic print original images are regularly arranged with a blank portion in between,
A magnetic head having a detection region for detecting magnetism of the large-sized printed material and a mechanism for blowing air to the large-sized printed material;
A mounting shaft is provided in a direction perpendicular to the traveling direction when traveling on the large-sized printed matter, and a plurality of rollers that roll around the mounting shaft travel on the margin portion that sandwiches the printing original image. A provided traveling mechanism;
A head unit in which a plurality of magnetic heads are arranged adjacent to each other in a direction parallel to the mounting shaft direction between a plurality of rollers in the traveling mechanism;
Movement control means for performing control to move the head unit in the vertical direction close to the inspection surface of the large-sized printed material, and in the vertical direction and horizontal direction of the original print,
A printed matter inspection apparatus comprising: magnetic inspection means for performing a magnetic inspection of the large-sized printed matter based on a signal value acquired by the detection region in the magnetic head. The magnetic head is
It has a magnetic insensitive area on the outer periphery of the detection area,
The head unit is
A plurality of magnetic heads are arranged in a staggered manner so that the insensitive area in a predetermined magnetic head and the detection area in another magnetic head adjacent to the magnetic head overlap with each other in the traveling direction. The printed matter inspection apparatus according to claim 1. The head unit is
A magnetic head moving mechanism for moving the magnetic head parallel to the mounting axis direction while maintaining a relative distance between the plurality of magnetic heads;
The movement control means includes
The printed matter inspection apparatus according to claim 1, wherein the movement of the magnetic head by the magnetic head moving mechanism is controlled. The magnetic inspection means includes
Storage instruction means for instructing the storage unit to store the signal value for each magnetic head;
Extraction means for extracting from each signal value for each magnetic head stored in the storage unit a signal value without magnetism corresponding to a portion where there is no magnetic detection from the large-sized printed material;
Calculating means for calculating, for each magnetic head, an approximate curve representing a fluctuation history of the signal value without magnetism extracted by the extracting means;
And a correction unit that corrects each signal value for each magnetic head stored in the storage unit based on the approximate curve calculated for each magnetic head by the calculation unit. Item 4. The printed matter inspection apparatus according to item 1, 2 or 3. The plurality of magnetic heads are
The printed matter inspection apparatus according to claim 1, wherein the printed matter inspection apparatus is excited by an in-phase signal generated by a single oscillator.   The printed matter inspection apparatus according to claim 1, wherein a plurality of the head units are arranged.

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