JPS6361658B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for producing a printed draw-formed product, and more specifically, the present invention relates to a method for producing a printed draw-formed product, and more specifically, a method for producing a pot-shaped container or cap by drawing from a flat material such as metal. The present invention relates to an improvement in a method of pre-printing the flat material on a portion corresponding to the side surface of the final drawing-formed product, and displaying an error-free printed image in the state of the drawing-formed product. In particular, the present invention relates to a method in which a printing plate is created from a printing original by computer image processing.

Prior Art and Technical Problems of the Invention Drawing forming of surface-treated steel plates such as tinplate and stain-free steel, and metal plates such as aluminum is widely used in the production of so-called seamless cans (two-piece cans), metal caps, and the like. Painting or printing on individual molded bodies after molding requires complicated operations, so it is desirable to paint or print the flat material in advance before drawing.

In this drawing process, the flat metal material undergoes plastic flow and becomes a pot-shaped compact. Considering the plastic flow in the part of the flat material that will become the circumferential side wall of the final drawn body, this part will expand in the height direction of the body and contract in the radial direction. It is confirmed that there is.

Regarding pre-printing on a flat material for drawing, it is necessary to roll a rectangular original in the unfolded state onto a circular plate, taking into consideration the plastic flow of the material mentioned above. A conversion method is known.

In a method called the hand-drawing method, a rectangular transparent document with grid lines is wrapped around the circumferential side wall of a drawn body, and an area corresponding to the image of the document is drawn against an annular developed surface with squares corresponding to the grid lines. Paint by hand to create a plate for the flat material.
However, this method requires the skill of the operator to create the plate, as well as a great deal of cost and time.Moreover, the printed image that is actually reproduced on the circumferential side wall of the drawn product is not accurate. However, the results were still not completely satisfactory.

A technique has already been proposed in which a rectangular manuscript is optically expanded into a ring shape to make a plate.
- Publication No. 11388 describes a method of photographing a rectangular manuscript so that it is shortened in its height direction, wrapping the shortened photograph around a mandle, and photographing it again through a truncated conical mirror placed around it. describes the creation of a plate with an annularly developed image, and Japanese Patent Publication No. 48-23455 describes the preparation of a truncated conical prism with a hole in the center having an inner diameter that is approximately the same as the outer diameter of the can. , it is described that a rectangular original is placed on the inner surface of this hole, and an image of this original is photographed with a camera through the prism and a correction lens to create a plate having an annular surface.

However, these methods not only require troublesome operations and special optical equipment, but also have difficulty reproducing fine halftone dot patterns with high precision due to aberrations in the optical system. Moreover, each time the original of the drawn body changes, a troublesome conversion operation must be performed to create a plate.

Purpose of the Invention Therefore, an object of the present invention is to form an image of a rectangular document into a circular developed surface in fine and precise units of pixels (halftone dots), taking into consideration the influence of plastic flow of the material that occurs during drawing. To provide a method for producing a drawn object, which can be used to make a printing plate, thereby forming a defect-free printed image on the circumferential side wall of the drawn object in exact correspondence with the image of a rectangular original. .

Another object of the present invention is to provide a method for pre-printing a material for drawing forming, in which a planar plate developed into an annular shape from a rectangular printing original is created by digital computer image processing.

Still another object of the present invention is to provide a method for preparing a pre-printing plate for drawing material, in which the above-mentioned conversion process can be quickly performed using a relatively small-capacity computer.

Composition of the Invention According to the present invention, in a method of subjecting a pre-printed material to drawing forming and producing a drawn object having a printed image on the side wall of the formed object, an image to be printed on a document is photoelectrically scanned. , converting the rectangular coordinates into pixel signals on rectangular coordinates, and converting the rectangular coordinates to an annular surface having approximately the same area as the rectangle so as to increase the number of pixels in the circumferential direction and decrease the number of pixels in the radial direction, When increasing the number of pixels, calculate new coordinates of pixels existing in gaps between converted coordinates corresponding to adjacent pixels of rectangular coordinates, read pixel signals on the converted coordinates in order of coordinates, and output to a printing plate. A method is provided, characterized in that the printing plate is used for printing a material.

Effect When a flat material is drawn, a contraction flow occurs in the circumferential direction and an elongation flow occurs in the radial direction in the side wall portion.

In the present invention, the image of a rectangular original is converted into an annular developed surface in pixel units, and this development is performed in consideration of the plastic flow during the drawing process described above. That is, when converting rectangular coordinates to an annular surface with approximately the same area as this rectangle, the number of pixels is increased in the circumferential direction and decreased in the radial direction, and when the number of pixels increases, the rectangular coordinates are The new coordinates of the pixel existing in the gap between the transformed coordinates corresponding to adjacent pixels are calculated.

If the number of pixels is not increased in the circumferential direction, the printing plate on the annular developed surface will become a perforated image, and the negative effect of this perforated image will also appear on the printed image on the side wall of the drawn product. This inconvenience can be solved by calculating new coordinates of a pixel existing in a gap between transformed coordinates corresponding to adjacent pixels of rectangular coordinates, and substituting a pixel signal into these new coordinates.

According to the present invention, by reading the pixel signals on the converted coordinates obtained in this way in the order of the coordinates and converting them into a printing plate, a rectangular original can be formed while taking into account the influence of plastic flow of the material that occurs during drawing. image can be made into a printing plate with an annular development surface finely and precisely in pixel units. In addition, by converting each image data of a rectangular document into a circular coordinate, or calculating new coordinates and substituting the converted coordinates, the conversion process can be performed even by a relatively small-capacity computer. become.

Preferred Embodiments of the Invention The present invention will be explained in detail below based on specific examples shown in the accompanying drawings.

In FIG. 1 showing a printed and drawn product, this printed and drawn product 1 consists of a bottom portion 2 and a circumferential side wall portion 3 that is integrally formed with the bottom portion 2 without a seam. is provided with a printing layer 4. In FIG. 2, which shows the circumferential side wall 3 developed, it will be understood that the printed layer 4 has a rectangular shape with a length L and a height H.

In Figures 3-A to 3-C for explaining the manufacturing process of this printed drawing-formed body 1, first, using a printing plate 6 on a flat metal material 5, a printing layer is developed into an annular shape. 7 (Figure 3-A). This annular printed layer 7 has an inner circumferential portion 8 approximately equal to the length L of the rectangular printed layer 4, an outer circumferential portion 9 which is greater than the length L, and a difference D between the outer circumferential radius and the inner circumferential radius. It is smaller than the height H of the rectangular printed layer 4, and the rectangular printed layer 4 and the annular printed layer 7 have substantially the same area. The printed metal material 5a is cut into a circular blank 12 using a combination of a shearing die 10 and a shearing punch 11 in the shearing process shown in FIG. 3-B.
Punch out. Next, in the drawing step shown in FIG. 3-C, the circular blank 12 is sandwiched between a drawing die 13 having a diameter corresponding to the outside diameter of the molded body and a wrinkle presser 14, and the circular blank 12 having an outside diameter corresponding to the inside diameter of the molded body. The drawing punch 15 is pushed in to produce the drawn body 1 shown in FIG. 1.

According to the present invention, a printing plate having an annularly expanded printing image is created from a rectangular printing original as shown in FIG. 2 by digital image processing described in detail below.

In the block diagram of FIG. 4 for explaining the process of this image processing, the apparatus used for this processing is, roughly speaking, a rectangular document 16.
An input scanning mechanism 17 for converting the image into an electrical signal; the pixel signal from the input scanning mechanism 17 is converted from analog to digital and input as a digital pixel signal, and if necessary, correction, cutting, etc. are performed based on this digital pixel signal. , position designation, trimming; editing operations such as compositing, and a well-known plate-making computer 18 capable of outputting digital/analog conversion of digital pixel signals; An output scanning mechanism 20 for manufacturing 19; a recording material 21 for storing data from the computer for plate making 18; and a coordinate system for digital pixel signals from the computer for plate making 18 from rectangular coordinates to annular coordinates having the same area as the rectangular coordinates. It consists of a transformation processing computer 22 for converting and re-inputting pixel signals on the transformed coordinates to the plate-making computer 18.

The input scanning mechanism 17 may be any known input mechanism, for example, one that reads one line of a document in the X-axis direction (main scanning), then shifts the position in the Y-axis direction (sub-scanning) and sequentially reads one line at a time. A cylindrical scanning type or a plane scanning type is used, and the reading operation is performed by detecting reflected or transmitted light using a photomultiplier tube, a phototransistor, a charge coupling device, etc. in general,
For multicolor originals, the colors are separated into cyan, magenta, yellow, and black, and input scanning is performed. Further, the number of scanning lines can be changed between a picture original and a character original. Such devices are widely marketed under the name of scanners and are easily available.

The prepress computer 18 is a central processing unit (CPU) that accepts input/output commands, analyzes them, executes various programs, controls input/output devices, etc.
It is equipped with a terminal device that issues commands to the central processing unit (CPU), and a station that performs image processing and editing, as well as a disk drive used to store the system and various files, and a disk drive used to store the system and various files. Equipped with a magnetic tape device used for backup and restoration. A suitable example of such a prepress computer is one commercially available from Cytecs of Israel as the Response 300 series, but the present invention is not limited thereto, and similar computers may be used. For example, studio
800 series (Crossfield, UK),
Plate-making computers such as the Chromacom system (Rudolf Hell, West Germany), the Page Matsik system (Dainippon Ink & Chemicals), and the Sigmagraph system 2000 (Dainippon Screen Mfg.) may also be used.

According to the present invention, the deformation processing computer 2
2, the rectangular coordinates are converted into digital coordinates into an annular surface having approximately the same area as the rectangle, and the new coordinates of the pixels existing in the gaps between the converted coordinates corresponding to adjacent pixels of the rectangular coordinates are calculated, and the plate-making computer The pixel signals on the rectangular coordinates input to 18 are substituted into the corresponding transformed coordinates and new coordinates, and the pixel signals on the transformed coordinates are read in the order of the coordinates and output.

Flowchart 5 to explain this operation
In the figure, first, in step (i), data is read from digital pixel signal data from the plate-making computer 18, and then, in step (ii), data adjacent to the data in the X-axis direction of the rectangular coordinates is read.

Regarding the data read in steps (i) and (ii), in step (iii), the data →' and →' are converted between the rectangular coordinates and the transformed coordinates converted into an annular surface with the same area as the rectangular coordinates. Perform coordinate transformation and record as data '.

In Figures 6-A and 6-B for explaining this coordinate transformation, rectangular coordinates a, b (6th-A
(Figure 6-B) and the corresponding transformed coordinates a', b' (Figure 6-B)
is the formula a' = γ sin θ + O ... (1) b' = γ cos θ + O ... (2) In the formula, a' and b' are respectively rounded integer values, and the radius γ and angle θ in Figure 6-B are And the center O is the following formula θ=2πb/m...(4) The value is determined to satisfy .

At the time of this coordinate transformation, it is necessary to consider the influence of plastic flow during drawing of the flat material.
That is, in the annular surface shown in Figure 6-B, during drawing forming, contraction flow occurs in the circumferential direction and stretching flow occurs in the radial direction, so the number of pixels is increased in the circumferential direction during coordinate transformation. , it is necessary to reduce the number of pixels in the radial direction.

This operation is performed after step (iv) in FIG. That is, first, in step (iv), it is determined whether data adjacent to each other in the X-axis direction of rectangular coordinates are two points of continuous colors. If and are two points of consecutive colors, in step (v), 6-A and 6-B
According to the principle shown in the figure, the angle between ' and ' is increased by a fraction (for example, 1/5) from ', and a new coordinate value ' is calculated.

Next, in step (vi), compare the new coordinate value ``and the transformed coordinate value '', and if ``≠'', record ``'' in step (vii) and substitute the new coordinate value '' to . , in step (v), calculate a new coordinate value corresponding to the new increment of the angle, and continue this articulation in the same way until ′=″.

In step (vi), if '='' for the new coordinate value, step (viii) sets the rectangular coordinate data, and in step (ix), checks whether reading of the rectangular coordinate data has been completed. If it is not completed, new data is read in step (ii) and the above-described operation is repeated. In addition, in step (iv),
If it is determined that the data and are not two points of consecutive colors, then the next data is read.

Thus, according to the present invention, the correspondence between rectangular coordinate values and annular surface transformation coordinate values is easily performed, and
The new coordinates of pixels existing in the gap between the two converted coordinate positions obtained by this correspondence can be easily calculated, and by substituting the pixel signal on the rectangular coordinates to the converted coordinates or even to the new coordinates, the circumference can be calculated. It becomes possible to increase data in this direction in advance. Further, the reduction of the coordinate value in the radial direction is easily performed by making the data of a plurality of coordinate values of the rectangular coordinates correspond to one coordinate value of the converted coordinates (later entered data is stored).

In FIG. 5, if it is determined in step (ix) that reading of the rectangular coordinate data has been completed, in step (x), the vertical pixel coordinate is set to y=1, and in step (), the coordinate Among the converted and stored data, data whose Y coordinate is y is read.

Next, in step ( ), the read data is sorted and stored in ascending order of X coordinate (sort). In step (), it is determined whether or not the recording of the coordinate-transformed data has been completed. If it has not been completed, in step (), y=y+1 is set, the data is read in step, and subsequent operations are performed. Continue.

In this way, the coordinate-converted data is input to the prepress computer 18 in the order in which it was recorded.

According to the present invention, by the operations described above, a pixel signal on rectangular coordinates is made to correspond to a transformed coordinate when the rectangular coordinate is expanded into an annular surface having approximately the same area as this rectangle, and a pixel signal on transformed coordinates or It becomes possible to convert the pixel signals into a group of pixel signals, and to read and output the pixel signals on the converted coordinates in the order of the coordinates.

The pixel signals on the converted coordinates are supplied to the output scanning mechanism 20 in coordinate order, and a printing plate or block copy is created. The output scanning mechanism 20 may be any scanning recording method known per se, such as silver halide photography, dry silver recording, electrophotography, electrostatic recording, negative or positive photoresist recording, or photopolymer recording. Various methods can be adopted, such as diazo photography, dichromate gelatin plate making, electrolytic recording, discharge breakdown recording, current thermal recording, heat recording, pressure sensitive recording, and inkjet recording. Also, the scanning methods include mechanical scanning such as cylindrical scanning, rotating disk scanning, helix cylindrical scanning, belt type plane scanning, multi-needle electrode plane scanning;
Electron tube scanning systems such as a fly spot tube type, optical fiber tube type, and multi-needle electrode tube type; or solid state scanning systems such as a multi-needle electrode head type are used.

Among these various recording methods, the present invention has the advantages of concentrating optical energy in a minute area on the order of a wavelength, scanning a wide range of light beams, and quickly turning on and off the original. It is preferable to use a laser recording method for reading and printing. As a laser light source,
He--He laser, Ar laser, He--Cd laser, etc. are used.

In the present invention, the pixel density in the rectangular coordinates and the final transformed coordinates can be varied over a wide range as desired, but generally speaking, it is desirable to use within the range of 12 to 100 dots/mm; However, in the case of patterns, the range of 12 to 14 dots/mm,
In the case of letters and characters, it is desirable that the range is 36 to 100 dots/mm.

The output scanning mechanism 20 allows cyan, magenta,
Yellow and black plates can be produced directly and used for printing materials, or negatives can be produced once and then reverse baked to produce printing plates.

Effects of the Invention According to the present invention, when a digital pixel signal of a rectangular original is converted into a pixel signal of converted coordinates by coordinate conversion to an annular surface, the rectangular coordinates are converted to an annular surface having approximately the same area as the rectangle in the circumferential direction. Coordinate transformation is performed to increase the number of pixels and decrease the number of pixels in the radial direction,
When increasing the number of pixels, new coordinates of pixels that exist in the gap between converted coordinates corresponding to adjacent pixels of rectangular coordinates are calculated, taking into account the influence of plastic flow of the material that occurs during drawing. The image of a rectangular original can be made into a printing plate with an annular development surface finely and precisely in pixel units. This has the advantage that a defect-free printed image can be formed, and for each image data of a rectangular original,
By performing the circular coordinate transformation or by calculating new coordinates and substituting these transformed coordinates, there is an advantage that the transformation process can be performed even by a relatively small-capacity computer.

Furthermore, it prevents the effects of camera photography and development processing on images, such as image blurring and changes in density, making it possible to perform pre-printing with excellent fidelity and reproducibility on the drawing material, as well as to improve the quality of the plate. It becomes possible to significantly reduce the number of steps and processing time required for production.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a printed and drawn product;
The figure is an expanded view showing the circumferential side wall of the printed and drawn body shown in Figure 1, and Figures 3-A to 3-C illustrate the manufacturing process of the printed and drawn body shown in Figure 1. 4 is a block diagram for explaining the image processing process, and FIG. 5 is a flowchart for explaining the coordinate conversion operation and rewriting from rectangular coordinates to converted coordinates. 6-A and 6-B are diagrams for explaining coordinate transformation from rectangular coordinates to an annular surface. 1 is a printing drawn product, 2 is a bottom portion, 3 is a circumferential side wall portion, 4 is a printing layer, 5 is a metal material, 6 is a printing plate,
7 is a printed layer developed in an annular shape, 8 is an inner periphery, 9 is an outer periphery, 10 is a shearing die, 11 is a shearing punch,
12 is a blank, 13 is a drawing die, 14 is a wrinkle presser, and 15 is a drawing punch.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a drawn body having a printed image on the side wall of the formed body by subjecting a pre-printed material to drawing forming, in which an image to be printed on a document is photoelectrically scanned to determine rectangular coordinates. Convert the rectangular coordinates to the above pixel signal, transform the rectangular coordinates to an annular surface with approximately the same area as the rectangle, and increase the number of pixels in the circumferential direction and decrease the number of pixels in the radial direction. When increasing, the new coordinates of the pixels that exist in the gap between the converted coordinates corresponding to adjacent pixels of the rectangular coordinates are calculated, the pixel signals on the converted coordinates are read in the order of the coordinates, and output to the printing plate, and this printing A method characterized by using a plate for printing material.