JPH0829588B2 - Synchronous transport method for continuous printed matter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for synchronously transporting continuous prints in a defect detection system for prints continuously printed on roll paper.

(Technical background of the invention and its problems) In general, it is difficult to detect spotted ink scattering, printing defects such as doctor stripes, and defects such as dust adhesion when printing continuously at high speed. For this reason, a method is adopted in which the machine is stopped at the beginning or the end of winding to perform a visual inspection of only a small portion, or a visual inspection is performed by causing a strobe to emit light in synchronization with the roll paper feed speed. . However, due to non-exhaustive inspection and oversight of inspectors, defective products may be mixed inside, often causing problems. Therefore, there is a demand for the development of a high-speed defect detection system that can be used during operation. For example, the applicant has provided an automated defect detection method for printed matter such as the printed matter defect detection method disclosed in Japanese Patent Application No. 59-077300. Is becoming more common.

FIGS. 5 (A) and 5 (B) are diagrams for explaining the method for detecting print defects in the printed matter. The printed matter 1 continuously printed on the roll paper is designed such that a printing defect is detected by a printing defect detection device in a process continuous with the printing process or in a rewinding process. FIG. 1A shows the relationship between the printed matter 1 and the detection units 6A and 6B of the printing defect detection apparatus. The printed matter 1 and the detection unit 6A that is housed in the box and has its light-receiving surface facing the printed matter 1 are shown. 6B and 6B, and a control box 63 for receiving a detection signal from the detection units 6A and 6B and discriminating a printing defect. Then, FIG. 2B shows that the same patterns P1, P2, ... Are continuously printed on the printed matter 1 at a constant print pitch, and flow in the direction indicated by the arrow to be output. That is, P1 and P2 are printed on the same pattern.
The pair of detection units 6A and 6B are arranged with an appropriate interval with respect to the printed matter 1, and the pair of detection units 6A and 6B are arranged at positions displaced by one pitch or a few pitches in the pattern printing. There is. Therefore, the color sensor elements in the pair of detection units 6A and 6B are placed right above the portions of the same pattern,
As shown in FIG. 7B, the color sensor elements of the detection units 6A and 6B are located right above the same patterns P1 and P2. Under such an arrangement, the portions of the same pattern P1 and P2 of the printed matter 1 are irradiated with light from the pair of detection units 6A and 6B using a light source including visible light, respectively, and the above-mentioned patterns P1 and P2 are irradiated. The reflected light from the pair of detection units 6A
And 6B to receive light, calculate the difference voltage for red, green, and blue of the corresponding color sensor element between the pair of detection units, and compare the difference voltage with a preset set voltage to obtain a printed matter. It is made possible to detect the defect of.

In the printing defect detection method as described above, the portions of the same pattern are measured by a pair of detection units placed at positions shifted by one pitch or several pitches of printing, and the differential voltage between the pair of detection units is measured. Because we are comparing
The arrangement pitch of the pair of detection units must be an integral multiple of the printing pitch of the two patterns. However, continuous printed matter is printed at a constant pitch,
This printing pitch may change slightly due to the expansion and contraction of paper due to humidity, etc., and the change in tension during winding.
This amount of change may increase as continuous printing progresses. Therefore, in the printing defect detection method as described above, if the printed matter 1 is conveyed at the same pitch, the pair of detection units as described above cannot detect two portions having the same pattern, and the detection value There is a problem that the print defect cannot be detected by comparison.

FIG. 4 shows a printed matter 1 continuously printed on a conventional roll paper.
It is a figure showing an example of. In the figure, in the print column of this printed matter 1, the same patterns P1, P2, P3, P4, P11, P12, P13, P14, P21,
P22, P23, ... Are continuously printed at a constant print pitch PP. On the other hand, the printed matter 1 has a register mark PM1 for a printing machine, which is used for printing alignment such as multicolor printing on the printing machine.
PM2, PM3, ... Pitch CP corresponding to one rotation of the plate cylinder of the printing machine
Each pattern is printed at a predetermined position outside the printing column (in this case, four patterns are printed in one pitch CP), and this pitch CP is an integer multiple of the printing pitch PP of the pattern (in this case, 4
Double). Further, for example, synchronization register marks M1, M2, M3, M4, M1 used for alignment in a cutting machine or a packaging machine.
1, M12, M13, M14, M21, M22, M23, ... Are printed in the corners of each pattern for each of the above patterns. Furthermore, this printed matter 1
Is the print density check mark OM for confirming the density of this print.
1 and an all-color mark OM2 indicating a color sample of all colors used for this printing are also printed at a predetermined position (on the same line as the register mark PM for the printing press) outside the printing margin.
The register mark PM for the printing machine is printed, for example, by making the four colors used for this printing into four fine line segments, and each line segment is clearly printed. Also, the registration mark M for synchronization
Is a color in which each color used for printing the pattern P is overlapped during multicolor printing, and is printed with a line segment thicker than the four line segments of the register mark PM for the printing press.

Therefore, if the synchronization register mark M can be accurately detected, it is possible to accurately detect the deviation of the printing pitch PP of each pattern as described above. However, the synchronization register mark M is used for multicolor printing. The color may fade or the position may shift at the end due to printing misalignment, etc., and the line segment is thick and unclear. Therefore, only the synchronizing register mark M is detected to accurately determine the position of each pattern. Is extremely difficult to detect.
On the other hand, each line segment of the register mark PM for the printing machine is finely and clearly printed, and the above-mentioned pitch is provided at a predetermined position.
Since the CP is printed while maintaining a predetermined relative position with respect to the design, the relative position with the design does not change even if there is a deviation in the printing pitch as described above. Therefore, if the register mark PM for the printing press can be accurately detected, the deviation of the printing pitch for each pitch CP, that is, for each of the four patterns in this case can be accurately detected. However, as described above, other marks such as the density check mark OM1 and the all-color mark OM2 are also printed on the same line in the length direction of the printed matter 1 outside the printing margin of the printed matter 1 in addition to the register mark PM for the printing press. However, it is difficult to scan the outside of the printing area where the register mark PM for the printing machine is printed and to accurately detect each line segment of the register mark PM for the printing machine by distinguishing it. Also, in order to distinguish this printing machine register mark PM from other marks, if there is another margin different from the above position, it may be printed there, but in order to eliminate waste of paper at the time of printing. In addition, there is no margin other than the margin, and there is a problem that the printing pitch cannot be accurately detected.

(Object of the Invention) The present invention has been made under the circumstances as described above, and an object of the present invention is to print the continuous printed matter when detecting a printing defect of the continuous printed matter using a printing defect detection device. To provide a method for synchronously conveying a continuous printed matter capable of automatically detecting a printing defect by detecting a pitch and synchronizing the conveyance pitch of the continuous printed matter with an arrangement pitch of a printing defect detection unit of a printing defect detection device. It is in.

(Summary of the Invention) The present invention relates to a synchronization register mark printed at a predetermined position of each pattern of a printed matter in which the same pattern is continuously printed at a constant printing pitch, and the same in the length direction of the printed matter outside the printing column of the pattern. A register mark for a printing machine, which is printed on the line at an integer multiple of at least two times the printing pitch of the pattern and out of phase with the register mark for synchronization, and the register mark printed outside the printing margin of the pattern. At the same pitch as the pitch interval of the printing machine register mark on the same line as the printing machine register mark, and conveys a printed matter having a printing defect detection register mark printed in the same phase as the synchronizing register mark,
In detecting the presence or absence of a printing defect, the registration mark for synchronization is read by a scanning head of the mark to detect the registration mark for printing defect separately from other marks, and the printing is performed based on the detection signal. The conveyance pitch of the printed matter is adjusted so that the scanning register of the pair of printing defect detection register marks arranged at the pitch intervals of the printing machine register marks can detect the machine registration marks in synchronism with each other. is there.

(Embodiment of the Invention) The present invention has a printing defect detection register mark printed with a thin and clear line segment at a predetermined position of a margin portion of a column on which a register mark PM for a printing machine is printed. By detecting the print defect detection register mark separately from other marks, the position of each pattern can be accurately detected.

As shown in the external view of an example of the continuous printed matter used in the present invention of FIG. 1 (A), the pattern P of the pattern P is printed on the same line in the longitudinal direction of the printed matter 1 outside the printing margin of the pattern of the continuous printed matter 1. Between the printing pitch PP which is 4 times the printing pitch PP, one printing machine register mark PM, density check mark OM1, all-color mark OM2, etc., along with a printing defect detection register mark SM at a predetermined position in the margin. The print pattern is printed, and the print pattern has the above pitch over the entire sheet length of the print 1.
Printed continuously and repeatedly with CP. Further, a synchronization register mark M is printed at the corner of each pattern P. Here, for example, as shown in the enlarged view of the pattern P1 in FIG. 1D, the print defect detection register mark SM1 is in a direction orthogonal to the flow direction of the printed matter 1 within the width of the synchronization register mark M1. A line segment having a width narrower than that of the above-mentioned synchronization register mark M1 is printed on the outside of the print area of the register mark SM, and this print defect detection register mark SM also has the same pitch CP as the register mark PM for the printing press.
And is continuously printed in the same phase as the synchronization register mark M. Then, as described above, other marks are also printed in the column in which the print defect detection register mark SM is printed. When this column is scanned, the same figure (B) is displayed.
As shown in, the print defect detection register mark SM and other marks are detected, and it is not possible to detect only the print defect detection register mark SM only by scanning this column. Therefore, as shown in FIG. 6C, the corner of the pattern is scanned to detect the synchronization register mark M, and FIG.
By ANDing the signal shown in FIG. 8C with the signal shown in FIG. 7C, only the printing defect detection register mark SM is synchronized with the synchronization register mark M, so that it is distinguished from other marks. It can be detected accurately. By generating a gate signal based on the detected print defect detecting register mark SM, the specific mark PM1a can be detected from the register marks PM for the printing press shown in FIG.

With reference to FIGS. 2 (A) to 2 (E) showing the registration mark synchronization detection characteristics and FIG. 3 showing the configuration of a printing defect detection apparatus showing an application example of the present invention, the continuous printed matter of the present invention will be described below. The synchronous transport method of will be described.

In the printing defect detecting apparatus 9 for carrying out the method for synchronously conveying continuous printed matter of the present invention shown in FIG. 3, the continuously printed printed matter 1 is transferred to the in-feed roll 81, the tension pickup 80, the compensator roll 5 and the out-feed roll 82. It is designed to be rolled up and transported. A synchronization register mark / scanning head (SHC) 4C for detecting the synchronization register mark M is provided in the middle of the conveyance path.
A pair of printing machine register mark scanning heads (SHA) 4A and (SHB) 4B for detecting the printing defect detection register mark SM and the printing machine register mark PM are provided. Here, as shown in FIGS. 2 (A) and 2 (C), in synchronization with the detection of the synchronization register mark M by the synchronization register mark scanning head (SHC) 4C, the print defect detection is performed. The scanning heads (SHB) 4B and (SHC) 4C are spaced by an integral multiple of the pitch CP (in this case, 1 pitch CP) so that the registration mark / scanning head 4B detects the registration mark SM for printing defect detection. Are arranged. On the other hand, the pair of print mark detecting register mark scanning heads 4A and 4B are arranged at positions displaced by one pitch CP, for example. When the print defect detection device 9 starts the print defect detection from the pattern P1 in which the synchronization register mark M1 is printed at the corner of the pattern, FIG. 2 (A).
As shown in, the sync register mark scanning head (SHC) 4C reads the sync register mark M1, generates one pulse signal, and sequentially outputs M2, M3, M4, M11, M12, M13, M14, M21, …
One pulse signal is generated for each reading. Since the register mark / scanning head (SHC) 4C for synchronization and the register mark / scanning head (SHB) 4B for printing defect detection are arranged in synchronization with each other as described above, The register mark / scanning head (SHB) 4B is a register mark SM for printing defect detection.
When the column in which is printed is scanned, only the printing defect detection register mark SM that is synchronized with the pulse signal can be detected among the signals as shown in FIG. Here, a clock pulse CL as shown in FIG. 8E is generated in synchronization with the detection signal of the mark SM. The pulse number of the clock pulse CL is set in advance so as to correspond to the time lag when the scanning head (SHA) 4A reads the specific mark PM1a among the marks SM1 and PM1. Then, the gate signal G is generated at the same time when the counting of the clock pulse CL is completed. That is, FIG. 2 (C),
As shown in (E) and (F), when the scanning head (SHB) 4B reads the mark SM2, the clock pulse CL2
Occurs, and the gate signal G2
Occurs. By this gate signal, a pair of register mark scanning heads (SHA) 4A and (S
HB) 4B detects specific marks PM1a and PM2a from register marks PM1 and PM2 for the printing press. So this particular mark
If PM1a and PM2a can be detected in synchronism with each other, a control unit (not shown) determines that the conveyance pitches of the two patterns P1 and P11 are in synchronism. Here, since the time width of the gate signal G has a time width wider than each line segment of the register mark PM for the printing press, it is possible to specify the print deviation and the conveyance deviation within this time width. Mark of
PM1a and PM2a can be detected synchronously.

On the other hand, if the specific marks PM1a and PM2a detected by the pair of registration mark scanning heads (SHA) 4A and (SHB) 4B for printing defect detection are displaced as described above and cannot be detected synchronously, By moving the compensator roll 5 shown in FIG. 3 up and down, and adjusting the sheet length between the pair of print defect detecting register marks / scanning heads 4A and 4B, the pair of print defect detecting register marks.・ The scanning heads 4A and 4B have specific marks PM1a and
The PM2a can be detected synchronously, and the conveyance pitch of the pattern of the printed matter 1 can be synchronized with the arrangement pitch of the pair of print defect detecting register mark scanning heads 4A and 4B.

As shown in FIG. 3, the corresponding patterns P1 and P11 of the printed material 1 which are conveyed in synchronization as described above are obtained by transmitting the light emitted from the light source 61 through the optical fiber 62 in the X, Y, Z-axis precision. Bearing 7
The pair of detection units 6A and 6B as described above are supported by the projection unit, and the reflected light is measured by the pair of detection units 6A and 6B. The print defect detecting section 60, which has a color sensor element built in via 62, detects portions having the same pattern as each other, whereby the print defect is detected as described above.

Here, as described above, the printed matter 1 conveyed in synchronization with the four patterns between the pitches CP is
By comparing P1 and P11, P2 and P12, P3 and P13, P4 and P14, printing defects will be detected.
The print deviation between CPs is slight, and as described above, the deviation can be absorbed and synchronized within the pulse signal CL width of the gate signal G. When the printed matter 1 is conveyed by one pitch CP and a print defect is detected, the next print defect detection register marks SM2 and SM3 are detected by the pair of scanning heads 4A and 4B as described above, and Further, the conveyance pitch is synchronized, and the print defects are detected by comparing the patterns P11 and P21 as described above. Then, thereafter, the above-described synchronous conveyance and the print defect detection operation are repeated for the entire sheet length of the continuous print product 1, whereby the print defect can be accurately detected over the entire continuous print product 1.

(Modification of the Invention) In the above-described embodiment, an example in which four patterns are printed in one pitch CP has been shown, but the number is arbitrary.
Further, in the above-mentioned embodiment, the arrangement interval between the synchronization register mark scanning head (SHC) 4C and the print defect detection register mark scanning head (SHB) 4B is the pitch C.
Although it is an integral multiple of P, the arrangement interval is arbitrary as long as it is an integral multiple of the printing pitch PP.

(Effects of the Invention) As described above, when the method for synchronously conveying continuous printed matter according to the present invention is used, the printing pitch of the continuous printed matter is detected and the conveying pitch of this printed matter is synchronized with the arrangement pitch of the detection unit of the printing defect detection device. By doing so, it becomes possible to automatically and accurately detect the printing defect of the continuous printed matter by using the printing defect detection device.

[Brief description of drawings]

FIG. 1 (A) is a diagram showing an example of a printed matter continuously printed on roll paper used in the present invention, and FIGS. 1 (B) and (C).
2 (A) to 2 (H) are diagrams showing the register mark synchronization detection characteristics, FIG. 1 (D) is an enlarged view of a part of the printed matter, and FIG. 3 is a print defect detection showing an application example of the present invention. Device configuration diagram,
FIG. 4 is an external view of a conventional continuous printed matter, and FIGS. 5 (A) and 5 (B) are diagrams for explaining a printing defect detection method of the printed matter. 1 ... Printed matter, 4A, 4B, 4C ... Register mark / scanning head, 5 ... Compensator roll, 6A, 6B ... Detection unit, 9 ... Printing defect detection device.

Claims (1)

[Claims] 1. A registration mark for synchronization printed on a predetermined position of each pattern of a printed matter in which the same pattern is continuously printed at a constant printing pitch, and a pattern of the pattern on the same line in the length direction of the printed matter outside the printing column of the pattern. A register mark for a printing machine, which is printed at an integer multiple of at least 2 times the printing pitch and in a phase different from that of the synchronizing register mark, and the register for the printing machine, which is printed outside the printing margin of the pattern. A printed matter having a printing defect detection register mark printed on the same line as the mark at the same pitch as the printing machine register mark pitch and in the same phase as the synchronization register mark is conveyed to determine whether there is a printing defect. When detecting the print defect detection register mark by detecting the synchronization register mark with the scanning head of the mark, the print defect detection register mark is detected separately from other marks. Transport of the printed matter so that the scanning mark of the printing machine register mark can be synchronously detected by the scanning heads of the pair of printing defect detection register marks arranged at the pitch intervals of the printing machine register mark. A method for synchronously transporting a continuous print, characterized by adjusting a pitch.