JPH0512699B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing preprinted squeeze cans, and more particularly, the production of a printing plate developed on an annular surface from a rectangular original is optically performed. The present invention relates to a method for easily reading image data and writing image data by performing specific synchronous scanning without requiring conversion or coordinate conversion by a computer.

[Prior art]

BACKGROUND ART 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). Painting or printing on individual molded bodies after molding would complicate the operation, so it is desirable to paint or print the flat metal material in advance before drawing. For this reason, currently, DR cans and
Die-cut cans such as DTR cans and PC cans are usually printed on the can material before being formed, that is, in the form of a flat plate.

By the way, since the printing design on the can body is often provided as a rectangular original that is an image of the can body after the can body is made, some kind of process is required to ensure that the printed screen after the can body is faithfully reproduced in the original. It is necessary to perform plate making by converting (transforming) rectangular coordinates into circular coordinates.

In the past, this transformation work was done manually by skilled workers, but recently a special plate-making camera (Tokugan Showa)
59-98903), image data transformation processing by computer (JP-A-61-267053, JP-A-61-267053),
267763, Japanese Unexamined Patent Publication No. 62-93030), etc.

[Problem that the invention seeks to solve]

However, optical conversion methods using cameras, etc. require troublesome operations and special optical equipment, and furthermore, it is difficult to accurately reproduce fine halftone dot patterns 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.

In addition, in image processing methods using computers,
In order to convert a pixel signal on rectangular coordinates into a pixel signal or a group of pixel signals on converted coordinates, complicated program software is required and a computer with an extremely large capacity is required.

Therefore, an object of the present invention is to eliminate the need for troublesome optical conversion operations and coordinate conversion using a large-capacity computer when creating a pre-printed squeeze can plate from a rectangular original. The purpose is to provide a method that can be easily performed without having to do so.

Another object of the present invention is to read image data from a rectangular original by main scanning and sub-scanning, and to write image data by circular scanning and radial scanning in synchronization with the reading of image data for pre-printed squeeze cans. The purpose is to provide a method by which editions are created.

[Means for solving problems]

According to the present invention, a printing plate developed on an annular surface is created from a rectangular original, pre-printing is performed on a can material using this printing plate, and the printed can material is drawn and formed. In the method for manufacturing pre-printed squeeze cans, the image data of a rectangular original is read by main scanning and sub-scanning, the obtained image data is processed as necessary, a planar photoreceptor is used, and the A method for manufacturing a pre-printed squeeze can, characterized in that image data is written on a photoreceptor by a circular scan synchronized with the main scan and a radial scan synchronized with the sub-scan, thereby creating a printing plate. provided.

[Effect]

The present invention combines the reading of image data on a rectangular original by main scanning and sub-scanning, and the writing of image data on a flat photoconductor in a circular scan synchronized with the main scanning and in a radial direction synchronized with the sub-scanning. This is based on the knowledge that converting a rectangular original into an annular original is extremely simple and reliable.

In this specification, main scanning refers to the operation of extracting the image data of a document as a set of pixels in a fixed direction, and sub-scanning refers to the operation of shifting the main scanning in a direction transverse to the main scanning direction (perpendicular direction). . In the present invention, the main scan when reading image data is
Since this is related to circular scanning when writing image data, the main scanning direction for a rectangular original is the circumferential direction when the rectangular original is wrapped around the body of an actual squeeze can, and the sub-scanning direction is The direction is the can height direction in the above state.

Thus, according to the present invention, as long as the main scan during reading and the circular scan during writing are in a synchronous relationship, in other words, one main scan and one circular scan are in a corresponding relationship. As long as the read image data group is accurately converted into a circumferential image data group, and as long as the sub-scanning during reading and the radial scanning during writing are in a synchronous relationship,
A group of circumferential image data is accurately arranged in the radial direction, resulting in an image developed on an annular surface. Note that the above-mentioned circles and circumferences do not refer to strict meanings, but rather relate to the concept of approximate direction and shape.In actuality, when circular direction scanning and radial direction scanning are combined, the It should be understood that it becomes a spiral shape that is infinitely close to a circle, like a groove.

The printing plate made in this way is used to pre-print the can material, and the printed can material is formed into a cup-shaped can body using a combination of a drawing punch and a drawing die. Then, the annular printed image is also narrowed down and a rectangular image is reproduced around the can body. At this time, contraction occurs in the circumferential direction at the outer periphery of the annularly expanded image. Further, this outer peripheral portion may be stretched in the can height direction during drawing forming, but in that case, it is sufficient to increase the pixel density in the radial direction at this outer peripheral portion.

〔Example〕

FIG. 1 is a schematic explanatory diagram of a plate-making system in which the method for manufacturing pre-printed squeeze cans according to the present invention is specifically implemented. As shown in FIG. 1, the plate making system includes a scanner section 10 (original reading section), an image data processing device 11, and a plotter section 12 (display section or writing section).

The scanner section 10 consists of a reading head 13 and a cylindrical document support member 14.
A rectangular original 15 is wrapped around the outer peripheral surface of the document 4. Further, the document support member 14 rotates in the direction of arrow A in FIG. 1 when reading the document, and the reading head 13 rotates in the direction of arrow B (the axial direction of the document support member 14).
Move to. Therefore, the reading head 13 scans the rectangular original 15 in the vertical direction (main scanning direction) and the horizontal direction (sub scanning direction).
Read the entire area. The reading head 13 is rotated vertically by one rotation of the document support member 14.
Lines are read (main scanning), then shifted in the horizontal direction (sub-scanning) and sequentially read one line at a time.

The reading head 13 uses a photomultiplier tube, a phototransistor, a charge coupling device, etc., and detects reflected or transmitted light. Such a reading head 13 can easily read analog information of an image in units of pixels or halftone dots. Generally, in a multicolor original, 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.

Image data signals read by the reading head 13 are inputted to the image data processing device 11 at any time, and the image data signals are inputted to the image data processing device 11 as needed, and the image data signals are input to the image data processing device 11 at any time.
Editing operations such as transformation, character generation, masking, cutting, position specification, trimming, and compositing are performed.
However, here, it is not necessary to process the pixel signals of the image data into rectangular coordinates, and there is no need to convert the coordinates from rectangular coordinates to annular coordinates having the same area. Specifically, the plate-making processing apparatus is commercially available as the Response 300 series from Cytec in Israel, but the present invention is not limited to this, and similar devices may be used. For example, the Studio 800 series (Crossfield, UK), the Chromacom system (Rudolf Hell, West Germany), the Pagematik system (Dainippon Ink & Chemicals), the Sigmagraph system 2000 (Dainippon Screen Manufacturing), etc. can be used.

The image data signal processed for plate making is output to a plotter section 12, which is composed of a writing head 16 and a printing plate support plate 17. A plate-making photosensitive film 18 and a flat recording material are attached to the plate supporting plate 17 on its flat surface facing the writing head 16. When writing image data, the printing plate support disk 17 rotates in the direction of arrow C about the center point O in FIG. 1, and the writing head 16 moves in the radial direction (in the direction of arrow D in FIG. 1). That is, the printing plate support plate 17 is of a circular scanning type with respect to the writing head 16, and by this feature, the object of the present invention is achieved.

The writing head 16 can scan the photosensitive film 18 circumferentially and radially, and can write over the entire area of the photosensitive film 18. writing head 16
When the printing plate support plate 17 rotates once, one line is written in the annular direction, and then one line is sequentially written in the radial direction. Here, the rotational speed of the printing plate support plate 17 is determined by the rotation speed of the above-mentioned scanner section 10.
The rotational speed of document support member 14 is synchronized with the rotational speed of document support member 14, whereby the circumferential scan of write head 16 is synchronized with the longitudinal main scan of read head 13. On the other hand, the radial movement speed of the write head 16 is synchronized with the axial movement speed of the read head 13 of the plotter section 12, and the write head 16
The radial scanning of the reading head 13 is synchronized with the lateral sub-scanning of the reading head 13.

In the plate making method configured as described above, the image data read by the scanner unit 10 is transferred to the plotter unit 12 without computer processing such as coordinate conversion.
sent to. On the other hand, since the plotter section 12 employs a circular scanning method, an annular image is directly recorded on the photosensitive film 18, and a printing plate can be easily created. Furthermore, with the conventional camera photographing method, if the document changes, it is necessary to make complicated settings again. However, in the method for manufacturing pre-printed squeeze cans of the present invention, even if the reading position of the reading head 13 of the scanner section 10 is changed, it is easy to do so by correcting the position of the writing head 16 of the plotter section 12 using the image data processing device 11. can be dealt with.

The recording method of the photosensitive film 18 is silver salt photography, dry silver recording, electrophotography, electrostatic recording, photopolymer recording, negative or positive photoresist recording, and dichromate gelatin plate making. There are various methods utilizing electrolytic recording, discharge breakdown recording, energizing heat-sensitive recording, heat-sensitive recording, pressure-sensitive recording, inject recording, and the like.

The writing head 16 is of a fly spot tube type, an optical fiber tube type, or a multi-needle electrode type. Among these various recording methods, the laser recording method is used to create plates because it has the advantage of concentrating optical energy in a minute area on the order of a wavelength, scanning a wide range of light beams, and being able to turn on and off quickly. It is preferable to use As a laser light source, a He-Ne laser, an Ar laser, a He-Cd laser, etc. are used.

In the present invention, the pixel density can vary over a wide range as desired, but generally speaking, the pixel density is between 12 and 12.
It is desirable to use within the range of 100 dots/mm.
Among these, it is desirable to set the dots in the range of 12 to 14 dots/mm in the case of pictures, and in the range of 36 to 100 dots/mm in the case of letters.

Such scanner section 10 and plotter section 12
By configuring the printing plate, a printing plate having an annular development surface can be created with fineness and precision in units of pixels or halftone dots or more.

In the scanner section 10, a rectangular original 15 is scanned.
is attached to the cylindrical document support member 14, but the present invention is not limited thereto. For example, when a rectangular original 15 is attached to a flat fixed support plate as shown in FIG. 2, the reading head 13 of the scanner section 10 is reciprocated in the vertical direction (vertical direction) to perform main scanning. Good too. The reading head 13 reads one line or two lines in the main scanning direction each time it reciprocates in the vertical direction, and then shifts in the horizontal direction (sub-scanning) to sequentially read one line at a time.

On the other hand, the write head 16 of the plotter section 12
As shown in FIG. 3, spiral scanning is performed on a fixed photosensitive film surface 18 with an arbitrary point as the center, and main scanning and sub-scanning can be performed.
In this case, one line in the main scanning direction is written each time the write head 16 makes one revolution, and the write head 16 moves in the radial direction (sub-scanning direction) during one revolution.

In the scanner section 10 and plotter section 12, the writing head 16 is synchronized so that it makes one revolution every time the reading head 13 scans one line in the vertical direction (main scanning direction), and the reading head 16 rotates once every time the reading head 13 scans one line in the vertical direction (main scanning direction). The sub-scans of the head 13 and the write head 16 are synchronized.

In such a configuration, the prepress system is configured so that the reading head 13 only reads a rectangular original as shown in FIG. You can write images. As a result, the plate-making system can easily create an accurate annular development printing plate from a rectangular original without performing image conversion processing.

Metal materials for cans include untreated steel sheets (black plates), various surface-treated steel sheets, such as tin-plated steel sheets (tinplate), galvanized steel sheets, aluminum-plated steel sheets, nickel-plated steel sheets, chrome-plated steel sheets, etc.; electrolytic chromic acid treatment. Electrolytically treated steel plates such as steel plates; chemically treated steel plates such as phosphoric acid and/or chromic acid treated steel plates, light metal plates such as aluminum, or composites thereof, etc. are used.

The thickness of the base metal material varies depending on the final dimensions of the container and the type of material, but it is generally desirable to be in the range of 0.1 to 0.5 mm, particularly 0.2 to 0.35 mm.

For metal materials, paints with excellent processability and corrosion resistance, such as epoxy-phenol paints, epoxy-aminoplast paints, etc., are applied prior to printing.
Epoxy-acrylic paint, epoxy-vinyl paint, etc. can be applied, and the surface to be printed can be provided with a whiting paint made by blending titanium oxide or the like with the above-mentioned paint.

Printing can be performed by any printing method such as lithographic printing, offset printing, screen printing, gravure printing, letterpress printing, intaglio printing, electrophotographic printing, etc. using a plate manufactured by the method described above, and the printing ink is Any printing ink or ultraviolet curing ink known per se may be used.

In order to obtain a drawn can, the above-described printed metal material is punched out into a shape such as a disk, and subjected to one-stage or multi-stage drawing between a drawing punch and a drawing die. The total drawing ratio, expressed as the ratio of the material diameter to the bottom diameter of the drawn container, is generally 1.2 to 3.0, especially 1.3.
It is desirable that it be in the range of 2.9 to 2.9.

According to the present invention, when the can undergoes plastic flow due to drawing by the method described above, the annular developed printed image appears on the outer peripheral surface of the can as an accurate rectangular original image.

〔Effect of the invention〕

As explained above, according to the method for manufacturing a pre-printed squeeze can according to the present invention, image data of a rectangular original is read in the main scanning direction and the sub-scanning direction, the obtained image data is data-processed, and Using a plate, image data is written on the photoreceptor by circular scanning synchronized with the main scanning and radial direction scanning synchronized with the sub-scanning with the photoreceptor facing a writing means, thereby printing. By creating a printing plate, the image of the rectangular original is written on the printing plate more accurately than the unit of image or halftone dot, and pre-printing with excellent reproducibility on the drawing material is possible. Furthermore, since image conversion processing and the like are not performed in the plate making system, the number of steps and processing time required to create a plate can be significantly reduced, and printing plates can be easily created.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a plate-making system for manufacturing a pre-printed squeeze can according to the present invention, and FIG. FIG. 3 is an explanatory diagram showing a writing mode in a plate-making system for manufacturing a pre-printed squeeze can according to the present invention. 10...Scanner section, 11...Image data processing section, 12...Programter section, 13...Reading head, 14...Document support member, 15...Rectangular original, 16...Writing head, 17...Printing Plate support plate, 18...photosensitive film.

Claims (1)

[Claims] 1. A printing plate developed into an annular surface is created from a rectangular original, pre-printing is performed on a can material using this printing plate, and the printed can material is drawn and formed. In the manufacturing method of pre-printed squeeze cans, which consists of reading the image data of a rectangular original by main scanning and sub-scanning, processing the obtained image data as necessary, using a flat photoreceptor, A method for manufacturing a pre-printed squeeze can, characterized in that image data is written on a photoreceptor by circular scanning synchronized with the main scanning and radial scanning synchronized with the sub-scanning, thereby creating a printing plate. .