JPH0220438B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endless plate made from a manuscript for endless designs. In particular, even if there is a difference in density between the front and rear edges of the original, which should be continuous, the difference in density at the so-called seam, which is the part where the front and rear edges are connected on the endless plate, is eliminated. This is about the endless version that was created.

Traditionally, it has been used as a pattern for building materials (veneer, flooring, wallpaper, etc.), printed clothing, etc.
So-called endless designs (continuously repeated designs) are often used. In order to print such an endless pattern, a manuscript 1 for an endless pattern as shown in FIG. 1 is first prepared. As shown in the figure, such a document 1 has a pattern in which the front end A and the rear end B are continuous. For example, manuscript 1 with a wood grain pattern
When creating an endless pattern, a manuscript for an endless pattern is created by taking a photograph of the grain of the wood, and then redrawing the photograph from the photograph so that the front and rear edges form a continuous pattern. It takes many days for engineers to create it.

Based on the original 1, an endless plate 5 is made by engraving a plate-making cylinder so that its front end A and rear end B are accurately connected as shown in FIG. The line where the front end A and the rear end B are connected is called a seam P.

By the way, such endless design manuscript 1
Electronic plate-making devices for electronically making endless plates 5 have been developed since then, such as the heliocritogram.
K200 type (West Germany; manufactured by Dr. Ing. R, Hell) etc. are known.

To briefly explain the process of making an endless plate 5 from a document 1 using such an electronic plate-making device, the document 1 is mounted on a reading cylinder, scanned by a reading head, and the scanning lines R ₁ ,
Concentration signals S ₁ , S ₂ , S ₃ ... corresponding to R ₂ , R ₃ ...
(see Figure 2), and from the obtained density signal S, plate-making signals T ₁ , T ₂ , T ₃ ... (see Figure 3) are obtained, and this plate-making signal T is sent to the engraving head, and the plate-making signal T is Based on the plate-making cylinder, plate-making images U ₁ , U ₂ , U ₃ ...
An endless plate 5 is made by forming an endless plate 5.

Incidentally, the plate-made images U ₁ , U ₂ , U _{3 .} . . are formed by halftone dots having a depth corresponding to the density. Although the density signal S and the plate-making signal T are shown as analog signals in the figure, they are actually digital signals sampled and digitized in correspondence with the halftone dots of the plate-making image U.

By the way, if there is a density difference Q between the front edge A and the rear edge B of the original 1, the seam P of the endless plate 5
A step in the density gradation occurs at a position corresponding to the seam P, and a printed matter printed with such an endless plate 5 becomes a defective printed matter with a step in density at a position corresponding to the seam P.

In Figures 2 and 3, the concentration difference Q
Although it is displayed in a large size, the concentration difference Q
Even if the value is so small that it cannot be detected by a densitometer, a difference in density gradation will appear visually at the position of the seam P in the actual printed matter. When producing the original 1, it is extremely difficult to prevent the density difference Q from occurring between the leading edge A and the trailing edge B. For example, minute density differences often occur due to uneven development, etc. be. In such cases, corrections are made to the endless plate, the manuscript is rewritten, or the manuscript is corrected and re-produced, but in any case, an extremely large amount of labor and time is required, and a large amount of time is required to make the endless plate. It was becoming a problem.

The present invention was developed to eliminate the drawbacks of the prior art, and is obtained by scanning a document using a document in which a continuous pattern is slightly extended at the front or rear end. The digital density signal obtained by inputting the digital density signal is input into a computer, and the computer corrects the corresponding density signal at the other end using the signal of the extended section. By modifying the density signal so that it gradually converts to , and making an endless plate based on the modified density signal, an endless plate in which the level difference in density gradation at the seam is eliminated can be provided.

The present invention will be explained in detail below with reference to Examples. The embodiment shown here is based on the aforementioned heliocritogram.
This is a K200 type electronic plate making device improved according to the present invention. Therefore, in explaining the present invention,
The parts known as the K200 electronic plate making device will be briefly explained.

FIG. 5 shows an endless pattern original 10 used in the present invention. In this manuscript 10, the front edge A and the rear edge B have a continuous pattern as in the conventional manuscript 1, and furthermore, the pattern at the front end is formed to extend longer than the conventional manuscript 1 at the rear edge B. ing. That is, the pattern in section AC and the pattern in section BD are the same pattern, and the two same patterns are formed in duplicate. In this embodiment, the length of the section BD, which is longer than the conventional one, corresponds to the number of samples (n = 200 in this embodiment, which is always constant regardless of the diameter of the plate-making cylinder, etc.). It has a long length.

The document 10 thus obtained is mounted on a reading cylinder 11 (see FIG. 10) for reading the density, and is scanned and read by a reading head equipped with a photoelectric converter, sampled, and A/D converted. The concentration signals W ₁ , W ₂ , W ₃ shown in FIG.
get... Although each signal is shown as an analog signal in FIGS. 6, 7, and 8 for ease of understanding, each signal is actually a digital signal. Here, the scanning line in Figure 5
V ₁ , V ₂ , V ₃ . . . The densities of the upper symbols correspond to the density signals W ₁ , W ₂ , W ₃ . . . respectively. The number of samplings from the front edge A to the rear edge B of the original 10 is determined based on the diameter of the plate-making cylinder to be made, and in this example, a plate-making cylinder with a diameter of 510 (m/m) is used for plate making, and the sampling number in that case is determined based on the diameter of the plate-making cylinder to be made. The number N is 2265, and the sampling number N matches the number of engraving halftone dots per line. The sampling number n of the section BD is designed to be constant 200 as described above.

Further, in this embodiment, the density signal W is an 8-bit digital signal.

The density signal W obtained in this manner is input to a computer to perform correction calculations. As shown in FIG. 7, this correction calculation uses the density signal of the extended section BD to correct the density signal of the corresponding section AC. In other words, the signal in section AC in the corrected concentration signal X _k is:
On the front end A side, the density value of the section BD is set, and on the end C side, the density value is set as the density value of the section AC, and the correction calculation is performed such that the density value of the section BD is gradually converted into the density value of the section AC.

In this embodiment, such conversion correction operations are performed proportionally to distance. That is, let the i-th density value from the front end A be X _k,i .

[X _k,i = W _k,i ×i/n+W _k,(N+i) ×n−i/n X _k,(i−1) =X _k,i (i=2, 4, 6, 8 . . . n)] to obtain the corrected concentration signal (X _k,i ). In this way, when the ratio of a certain point in AC is i/n, the ratio of the corresponding point in BD is (ni)/n, and the calculation is performed so that the sum of the ratios becomes 1.

The reason why calculations are performed only for even numbers of i is to obtain high calculation speed.

In this way, the interval AC of the concentration signal W _k , that is,
W _k,1 ~ _{W k,o} is the signal of section B ~ D, that is, W _k,N+1 ~
W _k,N+o and others, i.e. W _k,o+1 ~ _{W k,N}
As is, the corrected concentration signal X _k,1 ~
Get X _k,N .

The modified concentration signal X obtained in this way
is converted into a plate-making signal Y synchronized with the timing of plate-making, and this plate-making signal Y is sent to the engraving head after processing such as D/A conversion. The plate-making image Z is formed by engraving in the shape of halftone dots, and the endless plate 15
get. What is particularly noteworthy here is that even if there is a density difference Q between the front end A and the rear end B in the density signal W, there is a difference in density between the front end A and the rear end B in the corrected density signal There is no difference, and as a result, the difference in density gradation in the endless plate or printed matter is eliminated.

Next, the present electronic plate making apparatus will be explained in detail based on a block diagram.

As shown in FIG. 10, the reading cylinder 11 is loaded with an endless pattern original 10, which is formed by extending the pattern by a required length from the conventional original as described above. The reading head is moved while rotating the reading cylinder 11, and the reflected light from the original 10 is photoelectrically converted by the photoelectric converter 20 to obtain a density signal. The obtained signal is sent to the A/D converter 21, which performs sampling, 10-bit A/D conversion, etc.

The serial 10-bit digital concentration signal obtained in this way is sent to the serial/parallel converter 2.
The signal is inputted into the 10-bit/8-bit converter 23 and converted into a density signal having 8 bits, that is, 256 density levels.

Next, the concentration signal is sent to the channel selectors 25 and 27.
The signal is input to the engraving curve corrector 26 via the engraving curve corrector 26, where the signal is subjected to signal processing such as negative/positive conversion and gradation correction as required, and then input to the computer. Channel selector 25 and 2
7 is linked, and as shown in the same figure, 1 to 7 are linked.
Up to eight channels are provided, so that a plurality of reading heads and a plurality of engraving heads are operated in parallel to produce, for example, a large number of horizontally repeating designs at the same time. However, since this configuration is well known in the Heliocritiograph K200 type mentioned above, a description thereof will be omitted.

The density signal W outputted via the channel selector 27 is inputted to the CPU 35 via a CPU input register A30 and a CPU data input interface (I/F) 31. Then, the CPU 35 performs the correction calculation as shown in FIG. 7 and its explanation as described above to obtain the corrected density signal X, and the obtained density signal
Memory - storage device 4 via input register B37
0 and stores it in the storage device 40.

In addition, in this embodiment, the output signal X of the CPU 35 includes a signal of the extended section BD due to the design, and therefore, the storage device A 40 stores N+n pieces of data per scanning line. ,
The memory device 40 is configured so that only N pieces of data are read from the beginning and the n pieces of data that are no longer needed are erased from the storage device 40.

An address signal for storing the density signal X in the storage device 40 is generated from the write address counter 65 and input to the storage device 40 via the R/W address switch 67.

The address signal when the plate-making signal Y is read from the storage device 40 is generated from the read address counter 66 in accordance with the read sample pulse generated in synchronization with the rotation of the plate-making cylinder 45, and is generated by the R/W address switch 67. The data is input to the storage device 40 via. In this way, the plate making cylinder 45
The recorded density signal X is read out from the storage device 40 in accordance with the rotation of the plate making signal Y, so that the read plate making signal Y becomes a signal that is substantially continuous between each scanning line.

The plate-making signal Y is input to the D/A converter 42 and converted into an analog signal corresponding to the density value of each halftone dot, and then sent to the engraving head 43 and sent to the plate-making cylinder 4.
Carve 5 into a step shape. By thus engraving the pattern of the original 10 on the plate-making cylinder 45 to form the plate-making image Z, it is possible to obtain the book endless plate 15 with no step in density gradation at the seam P.

On the other hand, when the cylinder circumference size setter 50 sets the circumference size of the plate-making cylinder 45 to be plate-made (510 mm in this embodiment), that value is input to the calculator A51, and from the set value, one circumference is set. Number of dots per line N (2265 in this example)
Calculate.

This calculated value N is sent to the CPU via register C52.
35, and 1 circumference 1 in the above correction calculation
This is used as the number N of halftone dots per line.

In addition, N-1 is also calculated in the calculator A51, and this value N-1 is sent to the calculator B6 via the register D60.
1 is input.

This arithmetic unit B61 has a read/write (R/W) indicating the read mode and write mode of the storage device A40.
W) A signal is being input. Arithmetic unit B61 is R/
When W signal is in write mode, N-1+200=N+
199 is calculated to output N-1 in the read mode, and the output signal is input to the comparison circuit 63 via the register E62.

This comparison circuit 63 includes an R/W address switch 6.
The address signal from register E62 is also input, and the address signal is compared with the output signal from register E62.
When the value of the address signal and the output signal of register E match, a stop signal is sent to each counter 65 and 66 to stop counting of the counter. That is, in the write mode, when the write address counter 65 counts sequentially from 1 and the value reaches N+199, the comparison circuit 63 agrees with the output value of the register E62, and the write address is output from the comparison circuit 63. A stop signal is input to the address counter 65, and the write address counter 65 stops counting. Therefore, the storage device 40 has 0
Write addresses from 1 to N+199 are sequentially input, and N+200 sample values are sequentially stored. Also, in the read mode, read addresses from 0 to N-1 are sequentially input to the storage device 40 in the same way, and N sample values are sequentially output.

In this way, per scanning line, N+200 sample values are stored during writing.
At the time of reading, N sample values are read and 200 sample values used for correction are erased.

Although one embodiment of the present invention has been described in detail above, an application example of the present invention will be described below.

In the above embodiment, the density signal of the section BD is used to correct the signal of the section AC, but conversely, the signal of the section AC is used to correct the signal of the section BD. It's okay. Also, since the density signals of adjacent scanning lines are very fine between the scanning lines, the density signals are almost the same, so it may be corrected using the density signals of the adjacent scanning lines (for example, the density signals of the W _k section BD (configured to correct the signal in interval AC of W _{k+1 using the signal of W k+1} ).

Since the present invention has the above configuration, it has excellent effects as shown below.

That is, in the prior art, when creating a manuscript for endless designs, a density difference often occurs between the front edge and the rear edge, and the problem of such density difference could not be solved in the production of the manuscript. According to the present invention, even if the original has a density difference,
In this endless plate, the difference in density before and after the seam has been eliminated, and it is therefore possible to obtain printed matter without any difference in density.

Moreover, in order to obtain the endless plate of the present invention without such a difference in density, it is necessary to form a pattern that overlaps with the rear end (or front end) by slightly extending it from the conventional manuscript, and to form the overlapping design a little longer than that of the conventional manuscript. Since it is only necessary to make a plate based on a signal corrected using the density signal of , plate making can be done at almost no cost compared to conventional endless plates, and the time and labor required for plate making are essentially the same. The present invention has many excellent practical effects.

[Brief explanation of drawings]

Figures 1 to 4 explain the prior art.
The figure is a plan view of a conventional endless pattern manuscript,
The figure is an explanatory diagram of the density signal obtained by scanning the original in Figure 1, Figure 3 is an explanatory diagram of the plate-making signal obtained from the density signal of Figure 2, and Figure 4 is an explanatory diagram of the plate-making signal obtained from the density signal of Figure 2.
FIG. 3 is a perspective view of a prepress cylinder in which a prepress image is formed based on the prepress signal shown in the figure. Figures 5 to 10 show an embodiment of the present invention. Figure 5 is a plan view of an endless pattern manuscript used in the present invention, and Figure 6 is a diagram obtained by scanning the manuscript shown in Figure 5. FIG. 7 is an explanatory diagram of a density signal, FIG. 7 is an explanatory diagram of a corrected density signal, FIG. 8 is an explanatory diagram of a plate-making signal obtained from the corrected density signal of FIG. 7, and FIG. This figure is a perspective view of the endless plate on which a plate-making image is formed based on the plate-making signal shown in FIG. 8, and FIG. 10 is a block diagram of the electronic plate-making apparatus. 10... Original, 15... Endless plate, 20... Photoelectric converter, 21... A/D converter, 22... S/P converter, 23... 10 bit/8 bit converter, 25, 2
7... Channel selector, 26... Engraving curve corrector, 30, 37... Register, 31, 36... Interface, 35... CPU, 40... Storage device,
42...D/A converter, 43...Engraving head, 45...
Plate making cylinder, V...Scanning line, W...Density signal, X...Corrected density signal, Y...Plate making signal, Z...Plate making image.

Claims (1)

[Claims] 1. The front end A and the rear end B are continuous patterns, and the rear end B has a pattern with a section AC of the required length.
An endless plate made by an electronic plate making device from a manuscript 10 for an endless design that is continuously extended as a BD, and plate-making images Z ₁ , Z ₂ , Z formed on the plate surface of the endless plate. ₃ ... are the corresponding scanning lines V ₁ , V ₂ ,
The plate-making image Z, which is engraved into a halftone dot shape based on V ₃ ... and corresponds to the section AC, is [the i-th density from the end A of the section AC on the original 10]
×(i/n) + [i-th density from end B of section BD on document 10]×(ni-i)/n [Here, n is the number of samples in section BD. i is 0 at end A, end B, n at end C, end D, and A ~
A variable that sequentially increases from 0 to n depending on the distance between C and B to D. ] is formed based on the concentration of
The plate-making image Z corresponding to CB is a section on the manuscript 10.
An endless version characterized by being formed based on the density of the CB design.