JPH0358890A - Gravure printing method - Google Patents

Abstract

PURPOSE:To utilize the merits of both an etched printing plate and a machine- engraved printing plate, enhance stability of tone and obtain a well-balanced printed matter with good reproduction properties of fines lines of characters or the like, by making at least one printing plate by etching and making other printing plate by machine engraving. CONSTITUTION:Registering of a printing plate made by machine engraving and a printing plate made by etching is carried out by a method wherein assemblage of original films 9 for one cylinder is carried out by changing the position of the original film on the side of a gripper end 10 and on the side of a tail end 11, and controlling only the tail end 11 inwards or outwards along the axial direction of the cylinder, whereby the desired plate is made. As a result, a well-balanced printed matter with high accuracy of registering and favorable reproduction properties of fine lines can be obtained.

Description

[Detailed description of the invention] Industrial application field> The present invention provides a multicolor gravure printing method in which printing is performed using a plurality of plates that are a combination of a plate formed by m@engraving and a plate formed by etching. Regarding.

<Conventional technology> The Clavia printing method prints -M with richer and stronger gradation than other printing methods, and the printing speed is fast, making it suitable for magazines with large circulations, weekly magazines, etc. It is a printing method. The method of making the gravure printing plates used in this gravure printing method can be roughly divided into two methods: etching and mechanical engraving. This mechanical engraving method is now becoming mainstream because the reproducibility of the tone is stable, and the number of work steps is small, making the platemaking time short.

Furthermore, conventionally, a method of performing gravure printing using a mesh-resolved image such as a silk positive or a mesh negative for planography or letterpress is shown in Japanese Patent Publication No. 58-21259, for example, and Alternatively, a method of using a mesh positive for letterpress as a manuscript for mechanical engraving plate making, optically or electrically poking the halftone dots of the mesh positive, and then creating a gravure printing plate by mechanical engraving is also disclosed. Showa 56-1
This method is disclosed in Japanese Patent Application Laid-open No. 61167 and Japanese Patent Application Laid-open No. 126668/1983. <Problems to be Solved by the Invention> By the way, when performing gravure printing, gravure printing plates formed by mechanical engraving have poor fine line resolution compared to gravure printing plates formed by etching. When gravure printing is performed using a printing plate, it is said that parts that require fine line resolution cannot be reproduced well, such as Japanese characters used in the main text of magazines (usually printed in a black plate). There is a problem.

On the other hand, when reproducing a pattern, the ink version generally tightens the entire image,
In other words, it serves to give the image sharpness,
If the resolution is insufficient, there is also the problem that sufficient sharpness cannot be obtained for, for example, hair.

In addition, to make a plate by etching, a photosensitive sheet for plate (
(carbon tissue, pigment film, etc.), the conventional gravure method uses positives made of continuous gradations, and the method uses positives or mesh negatives (hereinafter referred to as halftones) for planography or letterpress printing. There is a gravure method, but most recent gravure uses the net gravure method, so to explain the process using the net gravure method, first, there is the process of printing a gravure screen on a photosensitive sheet (carbon tissue, pigment film, etc.). , a step of printing a halftone plate on the photosensitive sheet for printing,
Furthermore, if necessary, a process of sandwiching and printing a sales promotion sheet between the photosensitive sheet for plates and the halftone plate is performed, and then a gravure cylinder is etched through the photosensitive sheet for plates to obtain a gravure printing plate. It is.

In such an etching method, the cell 12 has a prismatic or cylindrical shape in the most shadow part, as shown in FIG. 6, and the volume of the cell can be made sufficiently large.

On the other hand, when a gravure printing plate is shaped by a-machine engraving, the shape of the engraved cells 13 is approximately pyramidal, as shown in FIG. The surface area of this cell is small in the light portion, and gradually increases from the intermediate tone portion to the shadow portion. In this case, the surface area of the cells cannot exceed a certain size because even the portion corresponding to the deepest part of the document must be independent as a cell of the gravure printing plate. This means that since the cell has a pyramidal shape, the cell molten area in the shadow portion is smaller than the cell molten area obtained by etching. That is, this means that a gravure printing plate obtained by mechanical engraving has a smaller amount of ink in the shadow area than a gravure printing plate obtained by etching.

Therefore, when a gravure printing plate in such a mechanical engraving method is used, the amount of ink tends to be insufficient especially in the shadow area. This ink shortage tendency is particularly noticeable in areas where the three colors of yellow, red, and eye should overlap, as a result of the accumulation of insufficient ink amounts, resulting in a noticeable ink shortage as a whole. Prints tend to lack depth in the shadow areas.

Therefore, an object of the present invention is to incorporate the advantages of both mechanical engraving and etching methods, and to achieve good resolution of characters and fine lines.
The objective is to provide a gravure printing method that achieves stability in tone and sharpness of the image, and requires fewer work steps.In particular, there are issues that need to be solved: If you print with a mixture of different printing plates, the registration will be off and the result will be unsightly. The present invention solves this problem of misregistration.

<Means for Solving the Problems> In order to solve the above-mentioned problem of misregistration, the present invention eliminates the alignment of the plates formed by mechanical engraving and the plates formed by etching when the film originals are assembled into one cylinder. ,
This is done by changing the position of the original film plate between the gripper side and the gripper end, adjusting only the gripper end inward or outward in the axial direction of the cylinder, and then performing plate making.

<Detailed Description of the Invention> The means for solving the above problems of the present invention will be described in further detail. The present invention relates to a gravure printing method using a plurality of plates, in which at least one plate is formed by etching, and the remaining plates are formed by mechanical engraving, and the plate formed by the etching and the mechanical engraving are formed. This is a gravure printing method characterized by aligning the registered plates using the following method.

Mainly when forming a publication gravure plate, 4 to 6 pages are printed in the circumferential direction of the plate, and 4 to 6 pages are printed in the axial direction.
This is usually done by laying out the page. Original film versions are often organized into four-page units. However, when shaping the plate by etching, the photosensitive film for the plate, such as carbon tissue or pigment film (a film-based film instead of the base of carbon tissue), is divided into two or three times in the circumferential direction. The plate is transferred to a cylinder to form a shape, or the film original plates are assembled into one cylinder for the plate, printed onto one sheet of carbon tissue or pigment film, and transferred to the cylinder forming the plate at one time.

The present invention is a method for avoiding the fan out phenomenon when transferring a large-sized plate photosensitive sheet to a plate cylinder in one go. When the printing pressure is applied, the difference between the beginning and the end of printing is like a fan, and the end of printing is 0.5 to the left and right.
This phenomenon occurs when the photosensitive film for printing plates is transferred to a cylinder for printing plates. As shown in FIG. 4, the photosensitive plate sheet 8 is transferred to the cylinder 5 by applying pressure with the transfer roller 4 while applying water 7. Figure 5 shows ran
This is an emphasized explanatory plan view of a state where an out phenomenon has occurred, and the gripper end 11 is spread out in a fan shape with respect to the gripper side 10 of the plate film 9. When all plates are formed by etching, the same fan out phenomenon occurs between each color plate, so the registration is correct, but when a plate formed by mechanical engraving and a plate formed by mechanical etching are mixed. A problem arises in which the position is misaligned.

In the present invention, as shown in FIG. 1, a film original plate for a double plate formed by etching is attached to a mount film.

The original plate for the plate formed by mechanical engraving is fano.
Since it has nothing to do with the ut phenomenon, paste it in the normal position of the Taigi film as shown in Figure 3. By doing this, even if a fan out phenomenon occurs during transfer, the plate formed by etching will be in register with the plate formed by mechanical engraving. On the other hand, if the etching is not adjusted and the mechanical engraving is carried out, the original film for the plate to be shaped by the mechanical engraving is pasted onto a mount film as shown in FIG.

This is to adjust the position of the film original plate in anticipation of the fan out phenomenon occurring in the plate formed by etching. At this time, the film original plate for the plate formed by etching is pasted in the usual position as shown in FIG.

<Operation> By aligning the plates formed by etching and the plates formed by mechanical engraving according to the present invention, a plurality of plates that incorporate the advantages of both the plates formed by etching and the plates formed by mechanical engraving can be created. This makes it possible to use a gravure printing method using a printing plate. Examples> The present invention will be explained in detail using examples.

Kazumi "L Example" A one-color photographic manuscript is scanned by a color scanner into Kiaka 2 Eye. I output a color-separated lithographic paper for the four colors of black and white. After performing the necessary retouching work on this net negative, a net positive for planography was obtained from a reversal process. These net positives were arranged according to a predetermined layout and pasted on transparent film in units of four pages, and for the blackboards, Japanese text was pasted through phototypesetting. In this case, the font size was 8 points and included kanji with many strokes. The thus obtained net positive was printed onto a PS plate, which is a printing plate for offsetting, and a proof print was made by an offset printing method. With this proof,
We checked the tone, color scheme, text, etc.

Next, film masters (net positives) were assembled and pasted onto the film base for each color plate, that is, one plate cylinder at a time. At this time, the black plate, which is shaped using mechanical engraving, is attached as shown in Figure 1, and the black plate is shaped using mechanical engraving. Aka version. The eye version is pasted as shown in Figure 3. The distance to the inside of the butt of the mouth is 0.15 mm on each side, totaling 0.
It was set to 3 mm. This distance varies depending on the type of photosensitive plate plate and transfer pressure. The maximum is about 0.5 mm. A plate cylinder is formed by using the film original plates that are assembled and pasted into each cylinder.

The original film for the black and red 7-eye plates formed by mechanical engraving is a photosensitive film (manufactured by Oriental Photo Industry Co., Ltd.,
It was closely exposed to light (trade name: Lumilite) and developed to obtain a net negative. This is a negative reflection type. This is attached to the original cylinder of a mechanical engraving device called Heliocryschograph (trade name) made by Hell, inputs a net negative image, electrically points the wire points, and then outputs it. This was mechanically engraved onto a gravure cylinder using an engraving needle, to obtain a gravure printing plate having pyramid-shaped cells. In this case, there were three gravure printing plates formed by A-machine engraving: a clear plate, a red plate, and an eye plate. On the other hand, the printing version of the ink version, which uses etching to form precepts, was obtained as follows.

First, a gravure screen was closely printed on the pigment film to form a latent image that formed a dot for supporting the doctor blade. After removing this gravure screen, a net positive for a black plate was closely printed on the same pigment film. The pigment film, in which the gravure screen was baked and the mesh positive for the black plate was baked twice as described above, was transferred to a gravure cylinder, developed with hot water, and etched with chloride solution. A gravure printing plate was obtained.

Using the four-color gravure printing plate obtained in the above manner, yellow, red, and red. Ai. When we performed gravure printing with four-color ink, the registration between the machine-engraved version and the etched version was good, and the pattern from light to shadow on the machine-engraved version was good. Stable key. Red.
A well-balanced tone reproduction of the eye, a good reproduction of the characters on the plate formed by the 7-inch process, and a printed matter with sufficient resolution were obtained. 1 unit and 1 The same film original plate as in Example 1 above was used. When attaching film masters to the film base for each color plate, that is, one plate cylinder at a time, the film master plate for engraving machine (Ki, Aka , for the Eye version) is pasted as shown in Figure 2. The distance by which the butt of the mouth was shifted outward was 0.15 mm on each side, for a total of 0.3 mm. The original version of the clothing film (for sumi version) that is shaped by etching is the third
Pasted as shown. A plate cylinder is formed by using the film original plates assembled and pasted into each cylinder in this way.

The following mechanical engraving and etching methods were carried out in the same manner as in Example 1 above to obtain a gravure printing plate.

Using the four-color gravure printing plate obtained as described above, gravure printing was performed with four-color ink of yellow, red, eye, and black. Good registration with the formed plate, stable key from light to shadow of the machine-engraved plate. Red,
A printed matter was obtained that had well-balanced tone reproduction of the eye, good reproduction of the characters on the plate formed by enoching, and sufficient resolution.

<Effects of the Invention> In the gravure printing method of the present invention, at least one plate is formed by enoching, and the other plates are formed by mechanical engraving, so the advantages of both are taken advantage of, and the stability of the tone is excellent. Moreover, a well-balanced printed matter with good reproducibility of fine lines such as characters can be obtained.

Furthermore, prints with good registration accuracy can be obtained between the etched version and the mechanically engraved version.

[Brief explanation of drawings]

Figure 1 is a plan view of assembled film original plates used for plates formed by mechanical engraving, Figure 2 is a plan view of assembled film original plates used for plates formed by mechanical engraving, and Figure 3. 4 is a partial cross-sectional view showing a transfer sheet, and FIG. 5 is an emphasized explanation of a state in which a fan out phenomenon has occurred in a transferred plate sheet. A plan view, FIG. 6a is an explanatory diagram showing the shape of cells of a gravure printing plate formed by the enoching method,
Figure 6b shows the A-AI! FIG. 7a is an explanatory diagram showing the cell shape of a gravure printing plate formed by a mechanical engraving method, and FIG. 7b is an explanatory diagram of the BB cross section thereof. l...Film base 2...Pictures for each page 3...Register mark 4...Transfer roller 5.
・・Cylinder 6・Gripping plate 7・
...Water shower 8,9...Photosensitive sheet for plate l
O... Photosensitive sheet for plate holding side 11... Photosensitive sheet for plate holding end l2, l3...
・Cell patent application Representative of Toppan Printing Co., Ltd. Kazuo Suzuki Figure 1 Figure 2 Figure 6 (a) Figure 7 (a Figure 7 (b+

Claims (1)

[Claims] (1) In a gravure printing method using a plurality of plates in which at least one plate is a combination of a plate formed by mechanical engraving and a plate formed by etching, the plate formed by mechanical engraving and the plate formed by etching are used. When assembling the film master into one cylinder, the registered plate is adjusted.
A gravure printing method characterized by changing the position of the original film plate between the gripper side and the gripper end, and adjusting only the gripper end inward or outward in the axial direction of the cylinder for plate making.