JPS59160709A - Method for measuring area of pattern on printing plate - Google Patents

Abstract

PURPOSE:To eliminate errors owing to the uneven density of a printing plate and to improve considerably the accuracy in measurement by measuring an area rate on the basis of the preliminarily provided blank region and the solid region in the pattern surface. CONSTITUTION:A blank region 17 corresponding to 0% halftone rate is provided over the entire region in the transverse direction of the position in the margin part 14 of a printing plate opposite to the pattern surface on at least one side with respect to the center in the transverse direction of said margin part. The average value of an electrical signal by the region 17 is used as a reference for 0% halftone rate and the electrical signal by the region corresponding to the max. halftone rate in the pattern surface 15 of the printing plate is used as a reference for 100% halftone rate. The electrical signal by the pattern surface is converted to an area rate by using the respective reference values.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a method for measuring a pattern area on a printing plate for offset printing or the like.

[Prior art]

Generally, in order to determine the amount of ink supplied to a printing plate, the pattern surface of the printing plate is divided into multiple zones and the pattern area ratio for each zone is determined. A method has been adopted in which the pattern area of the printing plate is measured based on the electrical signal corresponding to the reflected light.

That is, in the means disclosed in Japanese Patent Application Laid-Open No. 57-73608, the output value of the electric signal from the non-image area is set to a mesh ratio of 0 cm, the output value of the entire image area is set to a mesh ratio of 100 cm, and these are The output value in the middle part is converted to area ratio as a reference, but the maximum output value in the non-image area range is set to 0.
%, and the minimum value among the output values over the entire printing plate is taken as the standard of 100%.

However, in such a method, the printing plate is made by applying a photosensitizer to the surface of an aluminum plate, etc., which has been roughened by grain treatment, and then applying a hair arabic gum solution thereon.
Due to uneven surface concentration due to uneven grain treatment and uneven application of photosensitizer and arabic gum solution,
If the largest chain in the output chain is set as 0% and the smallest chain in the output chain is set as 100%, errors may occur due to non-uniform density, making it difficult to accurately measure the area ratio over the entire surface of the printing plate. It has the disadvantage that it cannot be used.

[Object and structure of the invention]

The present invention has the purpose of fundamentally eliminating the drawbacks of the conventional printing plate, and provides a blank area corresponding to a mesh ratio of 0% in the margin of a printing plate, and calculates the average value of the electrical signal due to the blank area to a mesh ratio of 0%. % standard, and the electric signal from the part corresponding to the highest mesh ratio on the picture surface of the printing plate is the mesh ratio of 100.
By converting the electric signal from the picture surface into an area ratio using each of these reference values, we have created an extremely effective printing plate picture that allows accurate picture area measurement results to be obtained. A method for measuring area is provided.

[Example] Hereinafter, the present invention will be explained in detail with reference to figures showing examples. First, Figure 1, which explains the prerequisites of the present invention, shows the surface density of a printing plate along the vertical direction with a number of samples of 667. Figure 2 shows the number of occurrences N for each concentration level when measured in the horizontal direction. As is clear, the density non-uniformity in the horizontal direction is greater than the density non-uniformity in the vertical direction.

This is due to the manufacturing process of the printing plate, in which a photosensitive agent is applied to a roll-shaped material plate, the material is cut, the image is printed on the raw plate, and then a gum arabic solution is applied. Non-uniform processing pressure and non-uniform coating conditions tend to occur in the lateral direction of the roll, and as a result, while there are relatively few non-uniformities in the center of the printing plate, the left and right edges are symmetrical. This results in non-uniformity.

Therefore, a blank area corresponding to a mesh ratio of 0% is provided over the entire horizontal area of the area corresponding to at least one image relative to the horizontal center in the margin of the printing plate, and the average value of the electrical signals obtained from this area is calculated as the mesh ratio. If there is a peta area corresponding to a mesh ratio of 100% on the picture surface of the printing plate, the electric signal obtained from this area can be used as a reference for the mesh ratio lO・0. The pattern area can be accurately measured even if there is uneven density of Φ. Figure 3 and subsequent figures are diagrams showing practical examples of the present invention based on the above prerequisites. A cross-sectional view of the imaging unit is shown. A lid 2 that can be opened and closed is provided on one side of the dark box 1. After adjusting the position with a guide pin (not shown in the figure), the pattern side is placed on the inside of the dark box 1. When the printing plate 3 is attached and the opening/closing lid 2 is closed, the printing plate 3 is supported in a planar shape V (supported by the transparent plate 4 made of glass or the like and the opening/closing lid 2).

Further, a light source 5 such as a fluorescent lamp facing the transparent plate 4 is connected to the transparent plate 4.
The picture surface of the printing plate 3 illuminated by the above is imaged by a television camera (hereinafter referred to as camera) CAM having solid-state photoelectric conversion elements arranged in a matrix. .

Note that an operation panel 6 is provided above the opening/closing lid 2, and this panel includes a cathode ray tube for display, a group of switches equipped with a lamp for display, a keyboard for inputting codes, and a printer, a magnetic card mechanism, etc. The output device is installed.

FIG. 4 is a diagram showing an imaging situation by the camera CAM, where (4) shows the solid-state photoelectric conversion element group of the camera CAM, and FIG. 4 (03) shows the inner surface of the opening/closing lid 2.

In this case, the solid-state photoelectric conversion elements are arranged in a matrix of 404 rows and 256 columns, and cover the imaging range 11, but the actual imaging range 12 that is actually imaged is The printing plate 3 is mounted within this actual imaging range 12 with its position regulated by a guide plate 13, although the range is not set smaller than this.

Further, the printing plate 3 is provided with a margin 14 around the periphery, and the only part that is actually printed is the picture side 15.
The horizontal width of the pattern surface 15 is L1, the vertical width is H1, and the distance between the guide pin 13 and the bottom edge of the pattern surface 15 is S, but each of these dimensions varies depending on the size of the printing plate 3. There is.

In this example, the pattern side 15 has a width of t and the width zone 2.
Correspondingly, the solid-state photoelectric conversion element group is apparently divided into groups of 8 each in the horizontal direction, and sampling for extracting video signals from the solid-state photoelectric conversion element group is performed. , for each group and sequentially and repeatedly in accordance with the horizontal arrangement order.

In addition, the margin area 14 of the printing plate 3 has a mesh ratio of 0% in offset printing over the entire area corresponding to the pattern surface 15 on the left side with respect to the horizontal center of the margin area 14.
A blank area 17 corresponding to the area is provided.

Alternatively, the blank area 17 may be provided in the upper margin 14 as long as it is within the actual imaging range 12, or may be provided over the entire horizontal area corresponding to the picture plane 15.

FIG. 5 is a block diagram of an electric circuit including the camera CAM. The video signal from the camera CAM undergoes peak value correction in a waveform correction unit WR, which will be described later, and then undergoes analog-to-digital conversion including a sampling and holding circuit. The measured value is converted into a digital signal by an A/D device (hereinafter referred to as ADC), and is stored in the variable memory RAM.

In addition, the contents of the variable memory RAM are read out by a processor CPU such as a microprocessor, and based on this, the processor CPU executes a predetermined operation, and then
After determining the area of each pattern for each zone 21 to Z8 and determining the corresponding ink supply amount for each zone 21 to Z8, the card is sent to the magnetic card mechanism MC and printer P via the interface I/F.
The camera CAM operates based on the synchronization signal from the control signal generator CG.1. The ADC-A/D performs sampling and holding and conversion operations based on similar sampling pulses, and also has a variable memory RA.
A similar addressing signal is given to M, and the outputs of the ADC/A/D are sequentially stored by this.

Note that the processor CPU executes predetermined calculations and control operations according to instructions stored in the fixed memory ROM, but the switch group S via the interface I/F
It operates in response to commands from W and the keyboard KB, and displays the operating status by blinking the lamp group PL via the interface 24'.

In addition, a start signal is given from the processor CPU to the control signal generator CG, and when the camera CAM finishes the imaging operation for one printing plate, an end signal is given from the control signal generator CG to the processor CPU,
In response to this, the processor CPU starts calculation.

FIG. 6 is a block diagram of the waveform correction unit WR, and FIG. 7 is a waveform diagram showing the waveforms of each part in FIG. 6. In FIG. The signal waveform corresponding to a sufficiently large area is shown on the left, and the signal waveform corresponding to a solid area with a small area is shown on the right. If the solid area of the same size is made into a sphere, the video signal shown by the solid line in the same figure (,) can be obtained. The upper p1 falls with the same fall time as the nu, but the peak value e1 corresponds to the light reflectance of the solid part.
It has become.

On the other hand, the video signal corresponding to a solid area with a small area falls at a peak value e2, which is smaller than the peak value e1, because it falls before it rises sufficiently due to the transient characteristics of the camera CAM. 0 However, the input terminal I in FIG.
When the video signal (a) is applied to the output terminal OUT, the output signal shown in FIG. Ru.

That is, as shown in FIG. 6, in this case, the rise time t
The first and second delay circuits D Ll and D L2 having the same delay time are connected in series, and the delay circuit DL1 delays the video signal (a) applied to the input terminal IN and outputs it. (b) and is further delayed by the delay circuit DL2 to output (C).

Further, the input of the delay circuit DL1, that is, the video signal (,), and the output (c) of the delay circuit DL2 are connected to the first adder A.
D D 1 adds and obtains the output /d), and then subtractor S
In the subtracter SUB, the output (b
) is amplified to twice the voltage by amplifier A, and the output <d) is subtracted from it, so subtraction is performed at the ratio of 2:1, and the output (e) is obtained.

The output (e) is given to the second adder ADD2 via the variable gain amplifier VAG, where it is added to the output (b), so the gain of the variable gain amplifier VGA is set to 1. For example, output ff) is obtained.

Note that the output (f) includes waveform distortion due to arithmetic processing, but if high frequency components are removed in the transmission system after the output terminal 0TJ-T, the waveform becomes as shown by the broken line in Fig. 7, The wave corresponding to a solid part with a sufficiently large area and the wave corresponding to a solid part with a small area have the same wave height value e30. Therefore, regardless of the size of the area, the wave corresponding to the solid part A high-value video signal can be obtained, and measurement errors can be eliminated. Note that the delay circuit DL1. The delay time of DL2 may be determined within the range of 0.5 to 1.5 times the rise time t depending on the waveform correction situation.
The gain may also be determined depending on the waveform correction situation.

71i: So, the same is true even if the amplifier A is omitted and a coefficient multiplier multiplied by 0.5 is inserted on the output side of the adder ADDt.
Depending on the situation, the variable gain amplifier VGA may be omitted.

FIG. 8 is a block diagram of the control signal generator CG, in which the clock pulse from the clock generator CLG is divided, and the synchronizing signal generator SG generates the horizontal synchronizing signal H8 and the vertical synchronizing signal VS. Along with black, a 3-bit counter CT is provided corresponding to the number of elements in the horizontal direction in each group of solid-state photoelectric conversion elements in FIG. Q
, Q I/ to XX11.1// are generated and fed to a digital comparator CP.

Note that the counter CT starts a new count after being reset by the horizontal synchronizing signal H8K. is to be repeated.

On the other hand, like the counter CT, a 3-bit frame address counter FAC is provided, and counts the vertical synchronizing signal V'S, and counts the vertical synchronizing signal V'S from \o, o, o/' to q1+1,1.
A count output of /7 is given to the comparator CP, and when the two outputs match, the comparator CP sends out a comparison output, which is then given to the horizontal address color HAC and ADC-A/D. .

The frame address counter FAC is reset in response to a start signal from the processor CPU and starts a new count, and when the count output reaches a full count of '1, 1.1', , and sends an end signal to the processor CPU.

For this reason, the solid-state photoelectric conversion element group of the camera CAM shown in FIG. Then, frame scanning is repeated according to the vertical synchronization signal VS, and the video signal from each solid-state photoelectric conversion element is extracted in the same way as in the standard television system, and sent to the ADC-A/D via the waveform correction unit WR. given to.

However, the sampling operation in ADC-A/D is as follows:
It is regulated by the comparison output of the comparator CP, and the count output when the 3-bit frame address counter FAC counts the first frame is 'Xo, o, o'', so the count output of the counter CT is Sl 6 ,0
．． 0// Since r comparison output is generated every time 0//, in the first frame, υ is indicated by the O mark in Figure 4.
Only the video signal from the solid-state photoelectric conversion element shown is ADC-A.
0 sampled by /D and converted into a digital signal, and in the second frame, the count output of the frame address counter FAC is 'o, o.

1'', so the count output of the counter CT becomes もQ
, Q , 1 // A comparison output is generated every time, and only the video signal from the solid-state photoelectric conversion element on the right side of the part indicated by the circle in FIG.
D is converted into a digital signal, and similarly, the third
In the frames to the 8th frame, each of the frames shown in FIG.
), the video signals from the third to eighth solid-state photoelectric conversion elements are sequentially converted into digital signals by the ADC-A/D. The photoelectric conversion element group is subjected to horizontal scanning in the same way as in the standard pre-vision system, but since the operation of converting the video signal to a digital signal does not require the response speed of the ADC-A/D to be low, the 8-frame one is used. Group light during scanning.

The scanning is performed every 8 times for the horizontal row of electrical conversion elements, and the entire scanning is completed by scanning 8 frames.

However, the same applies to continuous conversion into digital signals depending on the response speed of the ADC-A/D.

On the other hand, it is reset by the horizontal synchronization signal H3, and
A horizontal address counter HAC that counts the comparison output of the comparator CP and a vertical address counter VAC that is reset by the vertical synchronizing signal VS and counts the horizontal synchronizing signal H8 are provided. In this example, the horizontal address counter HAC generates a 6-bit count output, the vertical address counter VAC generates an 8-bit count output, the lower bits represent the 3-bit count output generated by the frame address counter FAc, and the lower bits represent the count output of the horizontal addressing signal IIAC. bits, the count output of the vertical address counter VAC is combined as the upper bits, and is given to the variable memory RAM as a total of 17 bits of addressing signal AD.
The output of the A/D is stored as a measurement value in the variable memory RAM according to the arrangement shown in FIG.

Variable memo') The measured value stored in the RAM is read out from the data bus DB in accordance with the address designation of the processor CPU via the address bus AB, as shown in Fig. 5, and is read out by the processor CPU's calculation based on this measured value. , the pattern area of each zone 21 to Z8 into which the pattern surface 15 is divided is determined.

Figure 9 is a diagram showing the contents stored in each memory RAM and ROM, and the figure shows a variable memo! JRAM, Figure (B) shows the contents of fixed memory ROM, variable memo! JRAM is
Measurement data area E12 for storing measured values; Calibration data area E2 for storing calibrated data; Attendance buffer area E3 used for temporary storage of input/output; Data processing area for temporarily storing data required during data processing. It is divided into a working area E4, a main routine working area E5, which temporarily stores data required when executing the main routine. ,)Also,
The fixed memory ROM is a main routine area E1 that stores the main routine. , subroutine area E that stores subroutines, i=, input/output format area E13 that stores data that determines the format of human output, 66 dimensions in FIG. 4(B), H, S, z,
Printing plate 3 that handles the number of divisions of zones 21 to Z8, etc.
A model data area E14 is stored for each type of , a calculation constant area E15 is stored with various calculation constants, and a correction table used when calibrating non-uniform illuminance using a calibration plate with uniform reflectance is stored. correction table area E1
6. Conversion table area E for solid color that stores the conversion table for solid color used when converting area ratio to ink supply amount
17. Mesh conversion table area EI8 that stores a mesh conversion table used in similar cases, and water amount conversion table area E19 that stores a water amount conversion table used for determining the amount of water supplied to the plate cylinder according to the area ratio. It is divided into two parts.

FIG. 10 is a comprehensive flowchart showing the control and calculation operations by the processor CPU. After the power is turned on, each part is initialized, and then a uniform light reflectance is set in place of the printing plate 3. Calibrate uneven illuminance, etc. using the calibration plate provided.

Next, after mounting the printing plate 3, using the keyboard KB or switch group SW, measure each dimension shown in ) in Fig. 4.
After giving l-I, S, t, the number of divisions of zones Z1 to zB, etc. from the data input process "K, and performing one measurement as described above using the circuit shown in Fig. 5," the sum calculation described later is performed. The same operation is repeated for each printing plate 3 for each color until "Measurement for N colors completed" becomes YES.

If the printing plate 3 used for separate printing is to be continuously measured, the steps from "Moodata Manual" are repeated if the first measurement is YES, but if this is NO, the series of operations is completed.

FIG. 11 is a flowchart showing the details of -Calibration, in which the lighting of the light source 5 is checked by the light source o K, /1, and if YES, the calibration execution display is displayed on the cathode ray tube CRT. Replace the printing plate 3 with a calibration plate with uniform light reflectance 11, and the turtle is ready.
If ``is YES,'' image the calibration plate with the camera CAM, obtain the measured value using the circuit shown in Figure 5, and store the measured value in the measurement data area l1z1%. Then, a correction value is obtained from the 9 correction tables in the correction table area ELS and stored in the calibration data area "E2".

FIG. 12 is a flowchart showing the details of the "data input process", in which the printing plate 3 is mounted by "electronic data input", and the six dimensions shown in FIG. When the zones z1 to Z, the number of C divisions, etc. are given, these contents are displayed on a cathode ray tube (CRT) in units, and the data for each color is displayed manually by IVc and by cis inch group S.
If you input the color of printing plate 3 from W or keyboard KB, it will be determined whether all the colors of printing plate 3 have been sequentially installed or not by inputting electrolytic color, and the N unit will continue until the result is YES. After repeating the steps from ``Display'' onward, if ``Input all colors?'' is YES, the input data for each color will be displayed on the cathode ray tube CRT by ``Data input confirmation display'', and the staff member who confirmed this will display the input data in the switch group SW. In response to operating the CR key, set the electrical input OK tt to YES.

FIG. 13 is a flowchart showing the details of "1 measurement", in which the CRT displays that the printing plate 3 has been correctly mounted according to the 1 printing plate setting instruction, and then
Check whether the opening/closing lid 2 is completely closed using a door switch, etc., and if it is completely closed, the first plate is set.) OK' is YES9, and the measurement value for the printing plate 3 is measured. Store in Taelya//E%.

Figure 14 is a flowchart showing the details of ``calculation''.
/E, ts and then compare the value of the measurement data area "El" X with the value of the calibration data area "E2" and update and store the subtracted value in the measurement data area "El'
B. Correct the measured values for printing plate 3.

Next, one maximum value A is selected from among the N measurement data areas //E%t, and data corresponding to the area corresponding to the maximum mesh rate is obtained, and then a blank area is selected from the measurement data area El. 17 data were extracted, the average value B of the Qi blank area was calculated by the calculation, and the Qi A
When the mesh ratio is 100 and B is 0%, the value of the measurement data area "El6" is converted to the area ratio, and the value is integrated for each "same vertical address" formed by each column of the solid-state photoelectric conversion element group I. After doing that, 1 for each sea/z1 to z8.
Perform integration for each zone.

Next, find the maximum value for each zone for each integral value.
Accordingly, calculate the water supply amount from the water amount conversion table in the water amount conversion table area E19.
0 Next, for each zone 21 to Z8, it is determined whether there is a peta part in that zone, and if the answer is YES, the ink supply amount is determined from the peta conversion table in the peta conversion table area EI7. If the determination result is No, the ink supply amount is determined from the mesh conversion table in the mesh conversion table area E18.

In addition, the above operation is repeated as long as "Is all zones completed?" is NO, and if it is YES, the calculation constant area E
The ink supply amount and water supply amount are multiplied by the coefficient read from ig to perform color-based correction, paper-side correction, and output form-based correction.

In addition, in the R final track, the ink supply amount is determined as the rotation of the ink fountain key that determines the ink supply amount to the ink roller in the printing machine, and the water supply amount is determined as the rotation speed of the water base roller. , recorded on a magnetic card or sent out as a printout by a printer PT,
Displayed on a cathode ray tube CRT.

The "thickest value" in Figure 14 is obtained by focusing on the maximum mesh ratio and multiple data in the vicinity of the maximum mesh ratio, and finding the intermediate value among these or the average value of these. It is preferable if it is used.

FIG. 15 shows the characteristics of the correction table stored in the correction table area Ei6, which is a logarithmic function curve.
Accurate measurement results can be obtained by determining the calibration value and correction value from the characteristic correction table shown in FIG. can.

In other words, the light reflectance of the solid area is RloG) mesh ratio OQ
If R6 is the light reflectance of - The ratio a of each measurement value under the amount of irradiation light is constant and is expressed by the following equation.

A 9Ro /A 1Rtoo =Ro /R+oo
=a °5"il) Also, equation (1) is expressed as X"'2.
It is shown by y and t.

Here, if we apply an arbitrary amount of irradiation light to the printing plate with only the solid area and obtain the measured value of a", then RO"
``Rloo-IL'', the measured value n obtained from a printing plate with only 0% mesh ratio is an''j.

Therefore, the following equation holds.

ノOgxo Logs】00 70 71(1,)= -to
ga noga -tOg&-toga'' toga = 1 (3) However, V O+ These numbers correspond to the printed version.

Therefore, no matter what the amount of irradiation light is, if you calculate the correction value for the measured value of the solid area and the measured value of the mesh ratio of 0% from the correction table shown in FIG. 15, and then calculate the difference between the two, Accurate values can be obtained even under an unrestricted amount of irradiation light.

The correction table shown in Figure 15 can also be created by calculating the above formula, but it can be done by preparing two types of test plates with slightly different light reflectances, varying the amount of irradiated light, and plotting the measured values of the amount of reflected light. Figure 16 shows the valley conversion table area E 17 + i”.
l Indicates the characteristics of the conversion table stored in 1g, where A corresponds to the conversion table for solid and B corresponds to the conversion table for mesh, and the integrated area ratio α corresponding to the pattern area for each zone Z+-Zs. is shown on the horizontal axis, and the corresponding pot key device K is shown on the vertical axis.

In other words, during printing, the amount of ink supplied to the solid area of the printing plate is increased to make the solid area clear after printing, but the amount of ink supplied to the low mesh area other than the solid area is reduced. It is necessary to prevent the ink from "extruding", and according to the experimentally determined characteristics shown in FIG.
By modifying the pot key device K every 8, good printing results can be obtained.

FIG. 17 shows the characteristics of the conversion table stored in the water amount conversion table area E19, with the integrated area ratio α taken on the horizontal axis and the corresponding water supply amount W taken on the vertical axis. Accordingly, the amount of water supplied to each zone 21 to z8 is determined so that the ink adhesion state of the printed matter is good.

In other words, if the amount of water supplied is large, the amount of ink adhering to the printing plate 3 will be reduced, and the printed pattern will become lighter. On the other hand, if the amount of water supplied and the amount of ink supplied are both dog, an emulsification phenomenon will occur due to the mixing of the two, making the peripheral boundaries of the printed pattern unclear, so the amount of water supplied is determined by the area ratio. It is necessary to make it appropriate according to α,
If the water supply amount W is determined based on the experimentally determined characteristics shown in FIG. 17, good printing results can be obtained.

However, the characteristics shown in Figures 16 and 17 are
They differ depending on various printing conditions, and it is only necessary to select the optimum characteristics according to the conditions.

The configurations shown in FIGS. 3, 5, and 8 can be selected arbitrarily as long as they achieve equivalent functions, and the number of solid-state photoelectric conversion element groups and the number of printing plates 3 in FIG. The mounting situation and the number of divisions of zones 21 to z8 may be determined depending on the situation, and in FIGS. 10 to 14, unnecessary steps can be omitted or the order can be changed according to the conditions. etc., the present invention includes various [
[Effects of the Invention] As is clear from the above explanation, according to the present invention, since the area ratio is measured based on the blank area provided in advance and the solid area within the picture surface, Errors are eliminated and according to the actual measurement results,
In the past, an error of 17 yen was caused for an area ratio of 100 cm, and an error of about +7 tchi for an area ratio of 0 cm, whereas in the present invention, an error of about -2 to +4 coefficient, an area ratio of Oq.
6, the error is about ±1%, which greatly improves the measurement accuracy. In addition, the blank area can be left as fabric, and no special processing is required, making it easier to produce printing plates. A remarkable effect can be obtained in measuring the pattern area of various printing plates.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the non-uniformity of density on a printing plate, Figures 3 and onwards show examples of the present invention, Figure 3 is a sectional view of the imaging section, and Figure 4 ■ is a diagram of the camera. A front view showing a group of solid-state image sensors, FIG. The figure is a waveform diagram showing the waveforms of each part in Figure 6, Figure 8 is a block diagram of the control signal generator, Figure 9 (B) is a diagram showing the stored contents of the variable memory, and Figures (, B) are fixed Diagram showing the contents stored in memory, 1st
Fig. 0 is a general flowchart showing the control and calculation operations of the processor, Fig. 11 is a flowchart showing details of "calibration", Fig. 12 is a flowchart showing details of "A data input processing", and Fig. 13 is a flowchart showing details of "one measurement". Figure 14 is a flowchart showing the details of 1 operation.
The low chart, FIG. 15 is a diagram showing the characteristics of the correction table, and FIGS. 16 and 17 are diagrams showing the characteristics of the conversion table. 1...Dark box, 2...Open/close lid, 3...Printing plate, 4...Transparent plate, 5...Light source, 14...Margin area, 15...・Picture surface, 17...Blank area, 21~z8...Zone, CAM@aφ・Camera (TV camera), converter), R'AM...Variable memory (memory), CPU ...Enthusiasm processor. Patent Applicant Komori Printing Machinery Co., Ltd. Agent Masaki Yamakawa (and 1 other person) 9 (A) (B) Figure 10 Figure 11 Figure 15 y Figure 16 (01o) Figure 17 ('/e) Procedure Written amendment (voluntary) 1. Indication of the case 1982 Patent Application No. 35151 2, Name of the invention Method for measuring the area of a printing plate 3, t) Person who makes a li correction Relationship with the case Patent Applicant 5, Subject of amendment (1) Specification Column for Detailed Description of the Invention (2) Drawing 6 Contents of Amendment (1) Page 4 of the Specification, Line 2 [Figure 1 shows... ” shall be amended as follows. [Figure 1 shows that multiple horizontal lines are set at equal intervals on the surface of the printing plate, the surface density is measured by setting measurement points at equal intervals for each horizontal line, and the measured values are averaged for each horizontal line. The average density value for each horizontal line is calculated, and the frequency N of occurrence of this is shown, indicating the average density distribution in the vertical direction on the printing plate. In addition, in FIG. 2, a plurality of vertical lines were set in the same manner as described above, measurements were made in the same way, and the measured values were averaged for each vertical line to obtain the average density value for each vertical line. This shows the frequency N of occurrence of this, and shows the average density distribution in the lateral direction on the printing plate. Therefore, (2) Figures 1 and 2 are amended as shown in the attached sheet. Fig. 1 U, 3U tJ, (1 Fig. 2

Claims (1)

[Claims] In the method of irradiating a light beam onto the surface of a printing plate and measuring the picture area of the printing plate based on an electric signal corresponding to the reflected light, the picture surface of at least one side of the printing plate with respect to the horizontal center in the margin area of the printing plate; A blank area corresponding to a mesh ratio of 0% is provided over the entire horizontal direction of the corresponding part, and the average value of the electrical signal from the blank area is used as a reference for the mesh ratio of 0%, and the maximum mesh ratio on the picture surface of the printing plate is set. A method for measuring a picture area of a printing plate, characterized in that an electrical signal from an area corresponding to the area is used as a reference for a mesh ratio of 100, and the electrical signal from the picture surface is converted into an area ratio using each of the reference values.