JPH02310053A - Gravure electronic engraving device - Google Patents

Abstract

PURPOSE:To obtain a sharp type on a plate surface by setting a first density value representing a minimum density value required for engraving cells, a second density value representing a minimum density value required for engraving a maximum-size cell, and a minimum cell width value representing a minimum size of cells to be engraved. CONSTITUTION:A function A is used for converting a density value to a cell width value. In the function A, a cell width value is invariantly 0 in the range of a density value lower than a predetermined value C1 or invariantly a maxi mum value W2 in the range of a density value higher than a predetermined value C2, or increases from a minimum value W1 to the maximum value W2 stepwise with the increase of the density value in an intermediate area of a density value of C1 to C2. With respect to a pixel with a density value lower than C1, a cell is not engraved at all. With respect to a pixel with a density value C1, a cell with the cell width W1 is engraved. Thus, only cells W1 or more in cell width exist on a plate surface. With respect to a pixel with a density value higher than C2, a cell with the maximum width W2 is engraved, and a cell area and an in-cell volume are increased as a whole.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a gravure electronic engraving device, and particularly to a gravure electronic engraving device that uses a stylus to create a printing plate for gravure printing by engraving cells corresponding to pixels. .

[Conventional technology]

Currently, two main methods are known for printing plates for gravure printing. One is a method called a corrosion method, in which a plate is formed by subjecting the plate surface to a chemical corrosion treatment. The other method is called an electronic engraving method, in which a plate is formed by scanning cells with a stylus across the printing plate and engraving cells corresponding to pixels. The former requires chemical treatment and has many unstable elements, whereas the latter requires physical treatment and has the advantage of being easy to process.

[Problem to be solved by the invention]

As mentioned above, the electronic engraving method has many advantages because it is a physical process, but it has the problem that the clarity of the printed characters is lower than that of the corrosion method.

In particular, the outlines of the printed characters become unclear, making it impossible to obtain sharp printed characters. This makes small print difficult to read.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a gravure electronic engraving device that can produce clear printed characters on a printing plate using an electronic engraving method.

[Means to solve the problem]

The invention of Section 1 of the present application includes a manuscript input unit that scans a manuscript to input it as a set of pixels with a predetermined resolution and obtains a density value for each pixel, and a plate that engraves cells corresponding to each pixel. an engraving section having a stylus for engraving, a drive device for vibrating the stylus, and a scanning mechanism for scanning the stylus against the printing plate; This function uses a function to convert to a width value to generate a cell width value corresponding to the density value obtained in the manuscript manual section, and then gives this cell width value to the engraving section to engrave a cell of the desired size. an engraving control unit having an engraving control unit; and an apparatus for producing a printing plate for gravure printing by an electronic engraving method, comprising: a first density value indicating a minimum density value necessary for engraving a cell; A second density value indicating the minimum density value necessary for the cell to be engraved and a minimum cell width value indicating the minimum size of the cell to be engraved are set, and the density value is the first density value. If the density value is lower than the second density value, it will generate a cell width value indicating not to engrave any cells; if the density value is higher than the second density value, it will generate a maximum cell width indicating to engrave the largest cell. and when the density value is between the first density value and the second density value, the cell width increases from the minimum cell width value to the maximum cell width value as the density value increases. A function is set to generate a value.

-41 The invention of Section 2 further provides that the density value is the first density value and the second density value.
A function is set in which the cell width value changes in a stepwise manner when the cell width value is between the density value and the cell width value.

[For production]

According to the invention of Section 1 of the present application, if the density value is lower than the first density value, no cells are engraved at all.

Therefore, only cells of a certain size or larger are present on the printing plate, and the sharpness of the outline of the type can be improved. Also, if the density value is higher than the second density value, the largest size cell is engraved. Therefore, the overall cell area and inner cell volume are increased, the amount of ink required during printing is increased, and high density printing is possible.

Further, according to the invention of Section 2 of the present application, when the density value is between the first density value and the second density value, the cell width value is changed in a stepwise manner, so that the printed characters are The size of the constituent cells is limited to several types. Thereby, the clarity of the printed characters can be improved.

〔Example〕

The present invention will be described below based on illustrated embodiments. FIG. 1 is a graph of a function used to convert a density value into a cell width value, which is a feature of the present invention. Before explaining this function, the overall configuration of the gravure electronic engraving apparatus of the present invention will be explained using FIG. This device has a manuscript input section 10.
, an engraving control section 20, and an engraving section 30. The document input section 10 has a document cylinder 11 and a reading head 12 . The document cylinder 11 rotates in the direction of the arrow, and the reading head 12 slides in a direction perpendicular to the plane of the paper. Therefore, if a document is pasted on the circumferential surface of the document cylinder 11, the reading head 12 can scan the surface of the document, and the document can be read by the reading head 12 as a set of pixels with a predetermined resolution. can. In other words, the density value for each pixel constituting the document is obtained.

These density values are sequentially given to the engraving control unit 20 in time series. The engraving control unit 20 converts this density value into a cell width value indicating the size of the cell to be engraved, as will be described in detail later.
This is given to the engraving section 30.

The engraving section 30 includes an engraving cylinder 31, a stylus 32 for engraving cells, and a drive device 33 for vibrating the stylus 32. A diamond needle 32a is provided at the tip of the stylus 32, and the entire stylus 32 vibrates around a fulcrum 32b. therefore,
The plate surface of the engraving cylinder 31 can be engraved with the tip of the diamond needle 32a. Engraving cylinder 31
rotates in the direction of the arrow, and the stylus 32 slides in a direction perpendicular to the plane of the paper. Therefore, the diamond needle 32a can be scanned with respect to the printing plate, and cells can be engraved at positions corresponding to each pixel forming the manuscript.

Figure 3 shows one engraved cell. FIG. 5(a) is a cross-sectional view perpendicular to the printing plate, and FIG. 6(b) is a view seen from above the printing plate. When viewed from above, it has a rhombic shape with diagonal lengths of X and y, as shown in FIG. 2(b). Here, the length
The direction is the rotation axis direction of the engraving cylinder = 7-31, and the direction of the length y is the engraving cylinder 31
Corresponds to the circumferential direction of The size of this cell is determined by the center position of the vibration of the stylus 32. Figure 4(a)
As shown in (b), compared to the case where the stylus 32 vibrates around the position shown by the broken line in the figure, the stylus 32 vibrates around the position shown by the broken line in the figure as shown in (b). When vibrating, the cells formed become larger. Therefore, when engraving a cell corresponding to a pixel with a large density value, the center of vibration of the diamond needle 32a is vibrated close to the plate surface to engrave a large cell, and a cell corresponding to a pixel with a small density value is engraved. In this case, if the center of vibration of the diamond needle 32a is moved away from the plate surface and the diamond needle 32a is vibrated to engrave small cells, cells corresponding to the density distribution of the original can be formed. The vibration of the stylus 32 is controlled by a drive 33. Drive device 3
3 is actually composed of a solenoid or the like, and is driven by a current corresponding to the cell width value given from the engraving control section 20.

Now, the operation of the engraving control section 20, which is a feature of the present invention, will be explained. In this embodiment of the apparatus, the density values provided by the read head 12 range from 0 to 100%. The engraving control unit 20 converts the density value given in this range into a cell width value, and supplies the drive device 33 with a current corresponding to this cell width value. The drive device 33 vibrates the stylus 32 at a center position that matches the applied current. In the end, cells of the size specified by the cell width value are engraved on the printing plate. In the graph shown in FIG. 1, the vertical axis indicates the density value (%) inputted by the engraving control section 20, and the horizontal axis indicates the cell width value (μm) outputted by the engraving control section 20. Further, a function A indicated by a solid line indicates a function used in the device according to the present invention, and a function B indicated by a dashed-dotted line indicates a function used in a conventional device.

With the conventional device, as is clear from the graph, the concentration value is 0.
As the cell width value increases from % to 100%
Function B that increases sequentially from m to the maximum cell width value
was used to convert density values to cell width values. In such an apparatus, as mentioned above, the problem with the prior art is that the clarity of the printed characters formed on the printing plate is reduced. A feature of the present invention is that function A is used instead of function B to perform the conversion.

The characteristics of function A are as follows.

(1) In a region where the density value is lower than the predetermined straight line C1, the cell width value is always 0.

(2) In a region where the density value is higher than the predetermined value C2, the cell width value is always the maximum value W2 (150 μm in this example).

(3) In the intermediate region between the density values 01 and 02, the cell width value changes stepwise and increases from the minimum @W1 to the maximum value W2 as the density value increases.

The C1 value is generally in the range of 10 to 60%, and the C2 value is 4.
Set so that C1<C2 in the range of 0 to 90%, and
The l value is approximately in the range of 30 μm to 150 μm, and W2@ is,
Maximum cell width at inter-cell pitch used ~ W1+10
Good character reproduction is possible when set to a range of approximately μm. In particular, the good plate making results shown in Figure 5(b) are as follows: C1 value = 40±10%, C2 value -60±1
0%, Wl value = 110 ± 30 μm, W2 value = 150 μm
It is obtained when each is set to . Note that the curve in the figure is used when engraving with an inter-cell pitch of 125 μm, but the pitch is 100 μm.

In the case of 185 μm, a corresponding curve will be used.

FIG. 5 shows a comparison between the plate production results obtained by the apparatus of the present invention and the plate production results obtained by the conventional apparatus. Figure (a),
(b) Both manuscripts use the same character ``%''; (a) is the printing type created by the conventional device (using function B), and (b) is the printed text created by the invention. Print type on a printing plate created by the device (using function A)
shows. If you observe both from a little distance from the paper,
It can be seen that the type in figure (b) is clearer than the type in figure (a). This is because the function A has three characteristics as described above. This 3
Each of these features is thought to have the following effects.

(1) For pixels with density values up to 01, no cells are engraved. Then, when the density value becomes 01, a cell with a cell width W1 is engraved. As a result, for pixels whose density value is less than 01, cells with a cell width less than W1 are not engraved. Therefore, only cells with a size equal to or larger than the cell width W1 exist on the printing plate, and the sharpness of the outline of the printed characters can be improved. In the type shown in FIG. 5(a), small cells are formed in the outline of the type, resulting in a blurred outline. On the other hand, in the same figure (b)
Because such small cells are not formed in typeface, clear outlines are obtained.

(2) For pixels whose density value is higher than 02, a cell with the maximum width W2 is engraved. Therefore, the overall cell area and inner cell volume are increased, the amount of ink during printing is increased, and printing with high density becomes possible. Figure 5(b)
The printed characters have a higher density than the printed characters shown in Figure (a).

(3) For pixels with density values between 01 and 02,
The cell width changes in steps. Therefore, the size of the cells that make up the typeface is limited to several types.

This improves the clarity of the printed characters. The type shown in Figure 5 (a) has cells of various sizes mixed together, but the type shown in Figure 5 (b) is composed of cells of only a few different sizes, which improves the clarity of the type as a whole. are doing.

The present invention has been described above based on an illustrative embodiment, but in short, the key point of the present invention is to convert a density value into a cell width value using a function having the above-mentioned characteristics.
The present invention is not limited to the embodiment using the function A shown in the figure.

〔Effect of the invention〕

As described above, according to the gravure electronic engraving device of the present invention,
If the density value is lower than the first density value, no cells are engraved. Therefore, only cells of a certain size or larger are present on the printing plate, and the sharpness of the edge portions of the type can be improved. Also, if the density value is higher than the second density value, the largest size cell is engraved. Therefore, the overall cell area and cell internal volume are increased, the amount of ink during printing is increased, and printing with high density becomes possible. Furthermore, the density value is the first density value and the second density value.
Since the cell width value is changed in a stepwise manner when the density value is between the density value of . Thereby, the clarity of the printed characters can be improved.

[Brief explanation of drawings]

FIG. 1 is a graph showing a function used to convert a density value into a cell width value in a gravure electronic engraving device according to an embodiment of the present invention, and FIG. The overall configuration of the device, Figure 3 shows one cell engraved by the device shown in Figure 2, and Figure 4 shows the second cell.
A diagram showing the vibration state of the stylus in the device shown in the diagram,
FIG. 5(a) is a diagram showing type characters engraved by the conventional apparatus, and FIG. 5(b) is a diagram showing type characters engraved by the apparatus of the present invention. 10. Manuscript input section, 11. Manuscript cylinder, 12.
...Reading head, 20...Engraving control section, 30...
Engraving section, 31...Engraving cylinder, 32...Stylus, 32a...Diamond needle, 32b...Fully point, 3
3... Drive device. Applicant's agent Hiroshi Shimura! l! Yukaku Zuto

Claims (2)

[Claims] (1) A manuscript input section that scans the manuscript to input it as a set of pixels with a predetermined resolution and obtains the density value for each pixel; a stylus, a drive device that vibrates the stylus, and a scanning mechanism that scans the stylus with respect to the plate surface;
and a function that converts the density value of a pixel into a cell width value indicating the size of the cell to be engraved, to generate a cell width value corresponding to the density value obtained in the original input unit. and an engraving control unit having a function of engraving a cell of a desired size by giving this cell width value to the engraving unit, and an apparatus for producing a printing plate for gravure printing by an electronic engraving method. a first density value indicating the minimum density value necessary for the cell to be engraved; a second density value indicating the minimum density value necessary for the largest cell to be engraved; and a cell to be engraved. and a minimum cell width value indicating the minimum size of the density value, and if the density value is lower than the first density value, a cell width value indicating that the cell is not engraved at all is generated, and the density value is If the density value is higher than the second density value, a maximum cell width value indicating engraving of the largest cell is generated, and the density value is the difference between the first density value and the second density value. In the gravure electronic device, the function is set so as to generate a cell width value that increases from the minimum cell width value to the maximum cell width value as the density value increases. engraving equipment. (2) In the gravure electronic engraving device according to claim 1, when the density value is between the first density value and the second density value,
A gravure electronic engraving device characterized in that a function is set in which a cell width value changes in a stepwise manner.