JPH03142304A - Measuring instrument for printing plate pattern area rate for offset printing - Google Patents

Abstract

PURPOSE:To improve the operability and the work efficiency and to reduce a failure of work by providing a device main body, a stage, a scanner, a suction device, a supporting means, a driving means, an arithmetic unit, and an output device. CONSTITUTION:A front panel 71 of a measuring instrument main body 70 is formed to a vertical slope, and a stage 74 is arranged in its center, and a printing plate is sucked to the stage 74 by a suction device 38. A scanner 10A incorporating a photoelectric detector is slidably arranged between guide rails 72 and 73. The scanner 10A is moved by driving a scanning rope to linearly scan the printing plate with the photoelectric detector. A keyboard 47 through which the operation of the scanner 10A is designated and inputted, a printer 48 which outputs scanning results of the scanner 10A, a magnetic card output device 100 which writes canning results of the scanner 10A on an inserted magnetic card and outputs it, and a power switch 110 are provided on the panel 71. An arithmetic unit 40 controls the suction device and the driving means to calculate the pattern area rate based on the signal obtained from the detector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for printing printing plates for offset printing presses.
The present invention relates to a picture area ratio measuring device for measuring the area ratio of a picture part).

By the way, as a method for measuring the picture area ratio, in addition to the method of measuring the picture area ratio from a printing plate, there are methods that detect proofs, prints from this machine, reflective originals, transparent originals, etc. Furthermore, there are methods that use this measurement value to check the density of printed matter during operation of the printing press and perform feedback control, and methods that preset the ink supply amount before printing.

However, in a normal printing plate, the pattern on the printing plate is a pattern obtained by arranging a plurality of manuscripts at predetermined positions and printing them. Therefore, when measuring objects other than printing plates and printed matter from this machine, there is a drawback that, after measuring the individual picture area ratios, the measurement data must be compiled based on the layout on the printing plate. On the other hand, if you measure a printing plate or printed matter from this machine, the measurement data can be used immediately, but if you want to obtain al constant data from printed matter from this machine, you cannot measure it after printing has started. Because of this, it becomes a feedback control system that corrects fluctuations due to disturbances during printing. On the other hand, when obtaining constant data from a printing plate, the purpose is to preset the opening degree of the ink adjustment key before starting printing, and to print a non-defective item from the time of starting printing.

Here, an example of a device that measures a printing plate is a device that wraps the printing plate around a tube and rotates it at high speed to measure the average afterimage of each section (for example, Japanese Patent Publication No. 47-4
No. 2205), or one that scans the original plate (printing plate) of an offset printing machine to obtain a pulse corresponding to the area ratio of the image area, and adjusts the ink supply amount using this (for example, Japanese Patent Laid-Open No. 48
-53804), detect and integrate the image lines on the printing plate for each ink adjustment key, detect the amount of reflected light in the non-image area using the auxiliary printing plate, and use the detection signal of the printing plate to detect and integrate the image lines on the printing plate. There is one that calculates the minus sign and converts it to a value corresponding to the area ratio of the image line to adjust the ink amount (for example, Japanese Patent Application Laid-Open No. 49-67714), and another that scans the original vertically and adjusts the ink amount in the width direction of the original. A device that measures the H occupancy of both lines and controls the ink supply amount at the ink source roller section (for example, Japanese Patent Application Laid-Open No. 51-2
No. 505), one in which the total amount of ink is determined by scanning a photoelectric detection device in the vertical direction at a predetermined position in the horizontal direction of the printing surface or plate surface, and the amount of ink is adjusted (for example, Japanese Patent Publication No. 47-47405) There is.

However, since none of these devices that detect printing plates can accurately detect printing plates, they are not practical.

That is, after contact exposure of a transmission film original, the printing plate is normally processed according to the processing steps shown in FIG. 1, which will be described next. Here, the development process (step Sl) of the normally used positive type printing plate removes the photosensitive layer in the areas exposed to light (non-image areas) and desensitizes it (prevents ink from adhering to the surface). However, any unnecessary photosensitive layer that remains in some areas even after the development process is removed by applying an erasing liquid only to those areas (step S3).
.

Next, after washing with water (step S4) and drying (step S5), a surface preparation liquid is applied to the entire printing plate (step S6).
) and then performs puff drying to dry the printing plate surface so that no leveling liquid remains on the printing plate surface (step S7). These surface smoothing treatments and puff drying are preparation steps for the burning (high-temperature heating) treatment, and then the burning treatment (step S8)
By doing this, the printing durability of the printing plate can be improved by 2 to 3 times.

Finally, a so-called gumming treatment (step 510
) to complete the printing plate processing process. In such processing steps, burning treatment is extremely effective for improving the printing durability of printing plates, but at 250' C~
Since the printing plate is heated at a high temperature of 300 @ C (7), as a result, a normal printing plate based on a hard aluminum plate will undergo thermal deformation, and even after cooling, it will be permanently deformed and the flatness of the plate surface will deteriorate. It gets worse. Therefore, if the amount of reflected light is detected to determine the picture area ratio from such a printing plate, the amount of reflected light will not only change depending on the picture area ratio but also change depending on the degree of unevenness and misalignment of the printing plate. Accurate detection accuracy cannot be obtained and the ink supply amount cannot be set correctly.

In addition, in places where a large number of printing machines of various types are maintained, it is common for many types of printing plates to be processed in the printing plate process, and the pattern area ratio meter from the printing plate is Rather than being integrated with the printing machine at the printing site, it is used integrated with the printing plate line at the printing plate site, and one All-in-one
It is desirable to measure data for ink conditioning of multiple printing presses with one installation. Therefore, an object of the present invention is to provide a quick picture area measurement device that satisfies such requirements, and is particularly easy to operate, improves work efficiency, and reduces work errors, and is easy to install and use. The idea is to reduce the space required for the work area.

This invention will be explained below.

In this invention, as shown in FIG. 2, a printing plate 20 is fixedly mounted below the movable charge detection devices 10 arranged in a row, and the charge detection device 20 is used to detect the charge using a conveying device to be described later. By moving the device 10, detection scanning of the printing plate 20 is performed linearly.

Therefore, the printing plate 20 used here has a rectangular or other shaped calibration mark 23 attached to the grip J of the printing plate 22 (the grip 21 or a portion that does not adversely affect printing). The calibration mark 23 has been fixed as the mark, or the solid part in the drawing area is fixed as the mark, and the non-printing area (At sand opening part) 2 is
4 and the drawing area (picture area) 25.

Further, the photoelectric detection device 10 is equipped with a pair of parallel cylindrical fluorescent lamps 11 and 12 that can form a linear irradiation surface, and the intermediate portion of the fluorescent lamps 11 and 12 is shown in FIG. SO, Sl, S2. ...
..., Sn photoelectric detectors 13 are provided. Therefore, the circuit configuration of this photoelectric detector (SO to Sn) is
As shown in the figure, there is a font diode PD that receives the opposite light from the printing plate 20 and converts it photoelectrically, and an operational amplifier O that uses this output as one input (the other input is grounded).
P, and a resistor R and a capacitor C connected between the input and output of this operation 1 widening device OP. The structure of the photoelectric detector 13 (SO to Sn) is as shown in FIGS. 5(A) and 5(B), in which a photodiode PD for photoelectric detection is attached to the upper end of a cylindrical shielding box 14. A slit 15 is provided at its lower end to receive and enter reflected light. Thus, it wraps around the slit 15 portion of the shielding box 14, shields the fluorescent lamps 11 and 12, and protects the printing plate 20.
A light-shielding box 17 is provided with a slit 16 at the bottom for receiving anti-fJJ light. Further, a partition plate 18 is provided between the detection part of the calibration mark 23 of the shielding box 14 and the part for detecting the pattern to partition the optical path.

Here, the actual configuration of such a photoelectric detection device 10 is shown in FIGS. 6(A), (B), and (C). Guide rails 72 and 73 are provided at the upper and lower ends, respectively, and the center of the front panel 71 has a rectangular shape f for mounting the printing plate 20.
Ma's stage 74 is arranged. In addition, print version 2
0 is positioned by pins 75 to 78 and is suctioned to stage 74 by suction device 38. Further, the stage 74 is made of a porous sheet or a plate having a large number of small holes.

Therefore, the scanning device 1 has a box-like concave structure and has the above-mentioned photoelectric detection device 10 built in between the guide rails 72 and 73.
0A is slidably disposed.

Note that the printing plate 20 is connected to the scanning device 10A and the stage 74.
It is designed to be inserted between the scanning device 1 and the scanning device 1.
By moving 0A in the M and N directions shown in the figure by driving the scanning lobe 31, the photoelectric detection device 10 disposed inside and below the photoelectric detection device 10 scans the printing plate 20 in a line. Further, near the side of the stage 74 on the front panel 71, there is an operation input device, such as a keyboard 47, for specifying the operation of the scanning device 10A, and a printer for outputting the results of scanning by the scanning device 10A on printed paper. 48
A magnetic card output device 100 and a power switch 110 are provided for writing the results of scanning by the scanning device 10A onto an inserted magnetic card and outputting the result for use in the next offset printing process. The panel arrangement of the magnetic card output device 100 is as shown in FIG. 7, with a card closet n101 for inserting a magnetic card, and a closet n101 for outputting a magnetic card written with predetermined data. A card output 102 provided above, a mode changeover switch 103 for changing the operation mode (check, normal, print), and an output mode (magnetic card only, printer only, magnetic card and printer dual h). An output changeover switch 104 for switching and a lamp 105 for indicating normal operation or malfunction are provided. The internal structure of the magnetic card output device 100 is as shown in FIG. It is transported in such a way that it is caught in the Limit switches SW2 and SW3 are placed above the rubber roller 107.
According to the detection timing, after predetermined data is written by the magnetic head 108, the magnetic card 106 is removed from the exit 102.
is now output.

Further, a rotary encoder 36 for detecting the position of the scanning device 10A is attached to the rotating shaft of the drive roller 91, and a printing plate 2 mounted on the lower part of the stage 74 is attached.
A suction device 38 consisting of a suction pump or the like for adsorbing zero is provided.

On the other hand, arithmetic processing unit 4 calculates the picture area ratio from the detection signal.
0 is the detection fJ from the photoelectric detector 13 at the beginning shown in FIG.
Amplifying circuit 41 (AO
~An), a multiplexer 42 that selects and outputs the signal from this amplifier circuit 41 according to a program of arithmetic processing, an AD converter 43 that converts the output of this multiplexer 42 into a digital signal, and a CPU (microprocessor). 44, a ROM (read only memory) 45 and a RAM (random access memory) 46 as storage devices, a keyboard 47 for inputting data and other necessary numerical values W, and a printer 48 for printing out the results of arithmetic processing. , a magnetic card output device 100 that outputs calculation results on a magnetic card, the AD converter 43 and the CP
Input/output control device 49 that controls input/output with U44 and others
It is composed of an input/output control device 49, a CPU 44, and an RO
The M45, RAM 46, keyboard 47, printer 48, and magnetic card output device 100 are interconnected via a bus. Further, the output of the rotary encoder 36 is input to the CPU 44 via a reading circuit 50 and a bus.

In such a configuration, a photoelectric detector 10 detects the amount of light reflected from the printing plate 20. If the relative positional relationship between the fluorescent lamps 11 and 12 and the printing plate 20 to be detected is set as follows, the detection error due to 11!1 t'h on the printing plate surface caused by burning process etc. can be reduced. Can be done. In other words, the above "relative positional relationship" refers to the first
As shown in FIG. More preferably, the printing plate 20 is set as a reference position away from the fluorescent lamps 11.12 by a distance M (X) in the range of 0.4 to 0.6 times, so that the printing plate 20 is equidistant from the two fluorescent lamps 11.12. The photoelectric detector 10 is set on the printing plate 2 so that the detection area is the periphery P of the position on the printing plate, and the photoelectric detector 10 is set so as to receive only the reflected light from the detection area P.
This refers to the optimal positional relationship for measurement when installed facing 0.

Therefore, the photoelectric detection device 10 in such a relative positional relationship
The effect of light transmission and reception between the printing plate 20 and the printing plate 20 will be explained. By the way, since the fluorescent lamps 11 and 12 are linear light sources, their illuminance is inversely proportional to the distance from the light source. In other words, in the case of a point light source, it is inversely proportional to the square of the distance from the light source, so in the case of a point light source, it can be thought that the point light sources are gathered in a line to form a linear light source, and the illuminance of a certain surface is If an integral calculation is performed assuming that the illuminance is the sum of the contributions of all point light sources, the illuminance is inversely proportional to the distance from the light source. On the other hand, the illuminance of a surface that is not perpendicular to the projected light beam is sin θ times the illuminance of the surface that is perpendicular to the projection light beam, where θ is the angle between the surface and the perpendicular surface. therefore,
The illuminance ■ in the detection area P in Fig. 10 is 1 (X)-A-X/ (K2+X2), where A is a proportionality constant.
...(1). Now, place the printing plate 20 at the predetermined position
If the positional deviation due to unevenness on the surface of the printing plate 20 is ΔXO, then in the above equation (1),
There is a difference in illuminance corresponding to the difference between the value when Xo and the value when the X amount is XO+ΔXO, and a measurement error corresponding to the difference occurs. By the way, the illuminance 1 (X) is a function that reaches its maximum value at <X-K as shown in Fig. 11,
Near the maximum value, illuminance 1 for the same position shift ΔXO
The change in (X) becomes smaller. Therefore, if the printing plate 20 is installed at the position of X- and the detection is performed with the detector 10 that detects the detection area P, IFI scanning with good particle size can be performed even if the printing plate 20 has unevenness. Can be done.

Also, 0.8K<X<1.2, that is, 0.4×2K<
Even in the range of X<0.6X2, the characteristics are almost linear, and a high particle size of 1ll11 is possible.

The operation of such a configuration will be explained with reference to the flowchart of FIG. 12.

When the printing plate 20 is placed on the stage 74 via the bins 75 and 76 and the power switch 110 is turned on (step Sl), the suction device 38 is activated and the printing plate 20 is moved onto the stage 74.
At the same time, the fluorescent lamps 11 and 12 are turned on, and the printing machine number and, for example, front printing or back printing in the case of a blanket-to-blanket type printing machine, are entered from the keyboard 47 (step S2). Further, the mode changeover switch 103 and the output changeover switch 104 are set to desired positions. By these input data, ROM
The data set in 45 is set. This R
AM46 or ROM45 data includes version size (
For example, 1310mm x 1050mm, 1160ml x
940mm), number of ink adjustment keys (e.g. 32,
50 pieces,...), key spacing (e.g. 30++s,
40 m, -), the distance between the key and the edge of the plate (for example, 5111% 10 lllm-).

), the distance #I between the printing effective area and the edge of the plate (for example, 22 degrees from top to bottom, 20 from left to right, 20 from left to right, . . . -), and the like. Accordingly, the use range of the photoelectric detector 13 (Sl-3k in FIG. 3), the spacing and number of ink adjustment keys, etc. are set (step S3), and when magnetic data is used, the magnetic card 106 is inserted into the insertion slot 101. The motor 93 is driven by pressing the measurement start switch, and the scanning device 10A slides in the M direction or N direction in FIG. 6(B) via the drive roller 91 and the scanning rope 31. The photoelectric detection device 10 built into the scanning device 10A detects and scans the surface of the printing plate 20. Further, the magnetic card 106 inserted into the insertion slot 101 is taken into the magnetic head 108 via a rubber roller 107. Note that the scanning position of the photoelectric detection device 10 is detected by the rotary encoder 36, and the scanning position of the photoelectric detection device 10 is detected by the rotary encoder 36.
The signal is sent to the PU 44, and the timing of the detection position and detection scanning movement are matched. Here, the irradiated light from the fluorescent lamps 11 and 12 in the photoelectric detection device 10 passes through the slit 16 and reaches the printing plate 20 (or stage 74), and the reflected light passes through the slit 16 again, and then passes through the shielding box 1.
The light reaches the photodiode PD through the slit 15 of No. 4, and is converted into an amount of electricity corresponding to the amount of light. Note that the charge detector SO in FIG. 3 detects changes in the amount of light from the light source (fluorescent lamps 11 and 12) due to power supply voltage, ambient temperature, etc., and the changes are corrected in subsequent data processing. In addition, the photoelectric detector SO detects the non-image area 24 and the calibration mark 23 in order to calibrate the upper and lower limits of the amount of reflected light, and the photoelectric detector Sk detects only the detector output within the printing effective area as data. It is used to incorporate as. Note that the photoelectric detector for performing the calibration is not limited to the SO shown in FIG. 3, but can be freely selected depending on the calibration position.

Thus, when the position information output from the rotary encoder 36 matches the edge position information of the printing plate set during the program, the amount of reflected light from the printing plate 20 is detected by the photoelectric detection device 10 (step S4), and the multiplexer 42
The detection data selected and output according to the program is AD
After being converted into digital data by the converter 43, it is input to the register of the C'P U 44 via the input/output control circuit 49 and the bus (step S5). When the data input for the portion corresponding to one ink adjustment key is completed (step S6), data is transferred from the register of the CPU 44 to the RAM.
46 (step S7). At this time,
The detection data of the calibration mark 23 and the amount of light from the light source are also processed in the same way. In this way, the output from each photoelectric detector 13 is selectively outputted by the multiplexer 42, and A
After D conversion, it is stored in the address of RAM 46 corresponding to the detection target (calibration mark, pattern, light source).
Rather than storing detection data once, multiple scans are repeated and stored. This makes it possible to reduce the influence of noise-based errors. Then, it is determined whether the number of all ink adjustment keys has been captured or not (step S8), and if the capture is completed, the calibration and light source light amount are corrected by arithmetic processing of the data in the RAM 46 after the completion of 111, and the total amount of light is corrected. Determine the pattern supply area, area ratio, and pattern area ratio for each ink adjustment key (step S9
). In this case, the detection data corresponding to the ink adjustment key is processed in the ROM 45 in accordance with the already set printing machine number.
Alternatively, this can be done by selectively using data such as the width and number of ink adjustment keys stored in the RAM 46. The picture area and area ratio thus determined are output from the printer 48 and the magnetic card output device 100 according to the selected mode of the output changeover switch 104 (step 510).

Here, an example of the contents of the data written on the magnetic card is shown in the first example.
3, and an example of the print is shown in FIG. 14. Note that the mode changeover switch 103 is in the normal mode at the time of the above measurement, and when it is switched to the check mode after 71-1 and the output magnetic card is inserted into the insertion slot 101, the data on the magnetic card is automatically transferred. Read and check whether there are any writing errors. However, if there is no mistake, the normal lamp 105 is lit, and if there is a mistake, the incorrect lamp 105 is lit, so in this case, the magnetic card is 11j times
When set to 1, rewriting is performed automatically.

As described above, according to the apparatus of this embodiment, regardless of differences in printing plate process or differences in printing plate brands, lots, and sizes,
In addition, it is possible to accurately measure the pattern area without being affected by thermal deformation distortion of the printing plate caused by burning processing, etc., and the #1 constant is compatible with the width and number of ink adjustment keys that differ depending on the type of printing machine used. I can do it. Therefore, a measuring device is not required for each printing machine, and only one device needs to be installed on the printing line.Also, because the measurement is from the printing plate, it can be used to measure holes, patterns, etc. from transparent originals (film originals), etc. It is not necessary to process measurement data regarding the layout of the printing plate, and the desired position between the printing plate and the detection device is not easily affected by mechanical errors of the device or deformation of the printing plate, so the device is simple, inexpensive, and highly accurate. It is possible to measure a high degree of Furthermore, in-line automatic measurement on the printing plate line is also possible, and the work load of the 8F1 standard is small. Therefore, image area measurement data can not only improve the operating rate of the printing press by presetting the ink adjustment key at the start of printing, and also have the effect of reducing defective prints, but also can be used to improve the quality of special color ink. Estimation of fi amount,
It can be applied in a variety of fields, such as reducing fuel consumption by optimizing the setting of off-wheel dryers.

Furthermore, since data regarding the area of the image can be written on a magnetic card, the work can be automated by sending this magnetic card to the next offset printing process. Furthermore, since the magnetic card is small, it can be easily attached to the printing plate after measurement, making it easy to handle, and the large amount of stored information makes it useful for storage for repeated work.

As explained above, according to the present invention, the shape of the device is vertical, and the input device and output device are provided on the front panel, which improves operability and increases work efficiency. It has the advantage of reducing the equipment space.

Furthermore, since the scanning device is moved relative to the printing plate, the work area required for the movement of the printing plate is reduced.

[Brief explanation of the drawing]

Figure 1 is a flowchart showing the printing plate processing process;
The figure shows the positional relationship between the movable photoelectric detection device and the printing plate according to the present invention, Figure 3 shows the state of detection scanning by the photoelectric detection device, and Figure 4 shows the configuration of detection elements in the photoelectric detection device. A circuit diagram showing an example, FIGS. 5(A) and (B) are a side view and a front view showing a schematic configuration of a photoelectric detection device, and FIGS. 6(A), (B), and (C) are measurements according to the present invention. A front view, a plan view, and a side view showing an example of the external configuration of the device, FIG. 7 is a diagram showing an example of the panel arrangement of the magnetic card output device, FIG. 8 is a diagram of its internal structure, and FIG. 9 is a calculation according to the present invention. A block diagram showing an example of the configuration of a processing device, FIG. 10 is a diagram for explaining the optimal relative positional relationship between a printing plate and a fluorescent lamp, and FIG. 11 is a diagram showing the relationship between distance X and illuminance to provide that explanation. Garden, 12th
FIG. 13 is a flowchart showing an example of the operation of the apparatus according to the invention, FIG. 13 is a diagram showing an example of data writing on a magnetic card according to the invention, and FIG. 14 is a diagram showing an example of printing by the printer according to the invention. 10... Photoelectric detection device, 11.12... Fluorescent lamp, 1
3... Photoelectric detector, 14... Shielding box, 15.16.
...Slit, 17...Shading box, 18...Partition plate,
20... Printing plate, 21... Bite, 22... Bite bottom, 23... Calibration mark, 24... Non-double line area, 25... Printing area (Printing H motion area), 36...
・Rotary encoder, 38... Suction device, 40...
- Arithmetic processing unit, 41... Amplifier circuit, 42... Multiplexer, 43... AD converter, 44... CPU
, 45...ROM. 47...Keyboard, 48...Printer, 4...
- Input/output control device, 50...Reading circuit, 71...Front panel, 72.73...Guide rail, 74...
Stage, 75-78... Bin, 100... Magnetic card output device, 101... Card insertion slot, 102...
・Card exit, 103...mode changeover switch, 10
4...Output selector switch, 110...Power switch.

Claims (1)

[Scope of Claims] A device for measuring picture area ratio from a printing plate for offset printing, comprising: a device main body having a vertically inclined front panel; and a large number of through holes provided on the front panel. A stage made of a flat plate, a light source for irradiating light onto a printing plate for offset printing placed on the stage while being regulated by a light shielding member, and a photoelectric detection device for detecting reflected light from the printing plate for offset printing. a suction device provided in the device main body to suction and fix the printing plate for offset printing through the through-hole of the stage; and a suction device that supports the scanning device so as to be slidable on the front panel. a support means for driving the scanning device to slide the scanning device with respect to the front panel; an input device provided on the front panel for inputting an instruction for measuring the picture area ratio; It has a function of controlling the suction device and the driving means based on an instruction inputted by an input device, and calculating a picture area ratio of the printing plate for offset printing based on a signal obtained from the photoelectric detector. A printing plate pattern area ratio measuring device for offset printing, comprising: a calculation device; and an output device provided on the front panel and outputting a calculation result of the calculation device.