JP2932500B2 - Gravure printing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gravure printing method for multicolor printing which is printed on a plurality of plates.

<Conventional technology> A gravure printing method is generally suitable for printing magazines, weekly magazines, etc. with a large number of copies due to the fact that the printing method is richer and stronger in gradation than other printing methods, and the printing speed is high. It is. The method of making a gravure printing plate used in this gravure printing method is roughly classified into a forming method by etching and a forming method by mechanical engraving.
Plates formed by mechanical engraving are more stable in tone reproducibility than plates formed by etching, and the number of working steps is shorter and the plate making time is shorter. is there.

Further, conventionally, a method of performing gravure printing using a halftone decomposed image such as halftone positive or halftone negative for lithographic printing is disclosed in, for example, Japanese Patent Publication No. 58-21259, and for lithographic printing. Alternatively, a method of producing a gravure printing plate by mechanically engraving a halftone dot of this halftone positive optically or electrically using a halftone positive for letterpress as an original in a mechanical engraving plate making process is also disclosed in Japanese Patent Application Laid-Open No. H10-163,086. This is disclosed in JP-A-56-161167 and JP-A-57-126668.

<Problems to be Solved by the Invention> By the way, in performing gravure printing, a gravure printing plate formed by mechanical engraving has a poorer resolution of fine lines than a gravure printing plate formed by etching. When gravure printing is performed using a plate, it is not possible to properly reproduce parts that require fine line resolution, such as Japanese characters used in the text of magazines (usually printed on a Sumi plate). There is a point.

On the other hand, in the reproduction of a pattern, the Sumi plate generally plays a role of giving the entire pattern, that is, giving the pattern a sheer-sharpness. If the resolution is insufficient, there is a problem that sufficient sharpness cannot be obtained with, for example, hair.

In addition, as a method of making a plate by etching, a conventional gravure method using a positive made of continuous tone shading as a method using a resist such as carbon tissue,
There is a halftone gravure method using a halftone positive or halftone negative for lithographic or letterpress printing (hereinafter referred to as halftone printing). However, most recent gravure uses a halftone gravure method. First, a step of printing a gravure screen on a photosensitive sheet for a plate (carbon tissue, pigment film, etc.), a step of printing a halftone on the photosensitive sheet for the plate, and, if necessary, a step between the photosensitive sheet for the plate and the halftone print. And a baking step with a diffusion sheet or the like in between, and then etching a gravure cylinder through the photosensitive sheet for plate to obtain a gravure printing plate.

In such an etching method, at the most shadowed portion, as shown in FIG. 9, the shape of the cell 12 is a prism or a column, and the volume of the cell can be sufficiently increased.

On the other hand, when the gravure printing plate is formed by mechanical engraving, the shape of the engraved cell 13 is substantially pyramidal as shown in FIG. The surface area of the cell is small in the light portion, and gradually increases from the intermediate adjustment toward the shadow portion. In this case, since the cells corresponding to the gravure printing plate need to be independent even in the portion corresponding to the shadow portion of the original, the surface area of the cells cannot be made larger than a certain size. This means that the cell volume in the shadow portion is smaller than the cell volume obtained by etching because the cell shape is a pyramid shape. That is, this means that the gravure printing plate obtained by mechanical engraving has a smaller amount of ink in the shadow portion than the gravure printing plate obtained by etching. Therefore, if a gravure printing plate in such a mechanical engraving method is used, the ink amount particularly in the shadow portion tends to be insufficient. And this shortage of ink amount,
In particular, in the portion where the three colors of the key, red, and eye should overlap, as a result of the accumulation of the insufficient ink amount, the insufficient ink amount appears remarkably, resulting in a printed matter lacking in the thickness of the shadow portion as a whole. Tends to.

Therefore, an object of the present invention is to take advantage of both the mechanical engraving method and the etching method, to obtain good resolution of characters and fine lines, to obtain tone stability and sharpness of a pattern, and to reduce the number of working steps. It is an object of the present invention to provide a printing method. However, as a problem to be solved, if a printing plate formed by mechanical engraving and a printing plate formed by etching are mixed and printed, misregistration is caused, resulting in unsightly printing.
The present invention has solved this problem of misregistration.

<Means for Solving the Problems> In order to solve the above-mentioned problem of misregistration, the present invention relates to registration of a plate formed by mechanical engraving and a plate formed by etching. 1) A photosensitive sheet for a plate during an etching process Is performed by changing the thickness of the grip plate between the first and second times. 2) When a film original plate is printed on the plate photosensitive sheet during the etching process, a spacer is placed between the plate of the second and subsequent transfer surfaces and the film original plate. 3) When printing the film original in the mechanical engraving process onto the photosensitive film for mechanical engraving, the spacer is placed between the holding plate and the film original only on the surface corresponding to the first transfer in the etching process. Is performed in the following manner.

The means for solving the above problems of the present invention will be described in detail.

The present invention relates to a gravure printing method using a plurality of plates, wherein at least one plate is formed by etching, and the remaining plates are formed by mechanical engraving, and the plate formed by etching is formed by mechanical engraving. The gravure printing method is characterized in that the register of the plates is adjusted by the following method.

1) When mainly forming a printing gravure plate, it is common to lay out 4 to 6 pages in the circumferential direction of the plate and 4 to 6 pages in the axial direction. Film masters are often grouped in units of four pages. However, when a plate is formed by etching, it is usual that the carbon tissue or the pigment film is disassembled twice or three times and transferred to a cylinder for forming the plate. To make it easier to understand, a description will be given of the case of 16 pages in the double division transfer, as shown in FIG.
A page of carbon tissue or pigment film is transferred twice in the circumferential direction, two by two. Strictly speaking, it must divide exactly at 180 ゜ of 360 ゜ of the circumference. However, in normal transfer, as shown in FIG.
Since the second transfer and the second transfer are performed as shown in FIG. 2, the positional relationship between the first transfer and the second transfer as shown in FIG. Not divided into If all the plates are to be etched, the other plates are similarly misaligned, so that they are in register. When a plate formed by mechanical engraving and a plate formed by etching are combined as in the present method, the plate formed by mechanical engraving is electrically divided into two parts, so that 180 ° is exactly produced. However, according to the present invention, as shown in FIG. 1, the thickness adjusting film 4 is provided at the first transfer so as to make the difference of the second time at the first time at the time of transfer, so that the film is formed exactly by 180 ° and machine-engraved. Match the position with the plate,
It is an object of the present invention to provide a gravure printing method in which a register is set at the time of printing.

2) The thickness of the holding plate at the time of the first transfer in the above 1) was adjusted with a thickness adjusting film. However, when the film original (positive film) is baked on a carbon tissue, only the carbon for the second transfer is used. As shown in FIG. 6, the thickness adjustment film 4 is sandwiched between the tissue holding plate and the blank portion of the film master (a portion of the register pin hole, etc.), and the first transfer is performed as before. Fig. 3, 2nd and Fig. 2 provide a gravure printing method which is performed as smoothly as shown in Fig. 2 so as to make an accurate 180 ° alignment with the plate formed by the mechanical engraving so that the register can be registered at the time of printing. Things.

3) The above 1) and 2) provide a method of adjusting the positional relationship of the plate formed by etching with the plate formed by mechanical engraving, and adjusting the plate so as to be in register when printed.
Conversely, in the invention described in the section, the positional relationship of the plate formed by mechanical engraving is adjusted to the plate formed by etching.

The plate formed by etching is not exactly divided into 180 ° by the ordinary transfer method as described in 1) above. This deviation is adjusted when printing a photosensitive film for mechanical engraving during the process of mechanical engraving.

Normally, a photosensitive film for printing an original used for mechanical engraving is a continuous polyester or lith-type photographic emulsion coated on a white polyester base containing opaque titanium white and scanned by reflection. At the time of printing the film master on the photosensitive film for the mechanical engraving machine, only the surface corresponding to the first transfer in the etching process, as shown in FIG. (A part such as a hole), and baking is performed with the thickness adjusting film 4 interposed therebetween. After that, development is performed by a photographic film automatic developing bar, which is a normal process, and then a register pin is used on a document drum of a machine engraving bar. Paste the original for mechanical engraving, scan and read the reflected light in proportion to the size of the halftone dot, convert it to a current value, move the diamond needle according to the current, engrave on the cylinder making the plate, etching it is formed by etching It is intended to provide a gravure printing method in which the positional relationship with the printing plate is adjusted so that the register is obtained when printing is performed.

<Action> By registering the plate formed by etching and the plate formed by mechanical engraving of the present invention, a plurality of plates incorporating the advantages of both the plate formed by etching and the plate formed by mechanical engraving are obtained. A gravure printing method using a plate becomes possible.

<Example> The present invention will be described in detail using an example.

Embodiment 1 In the gravure printing method of the present invention, for example, a plurality of gravure printing plates composed of four colors of yellow (Y), red (M), eye (C), and dark (BK) are used. The plate making method of the gravure printing plate is roughly classified into a forming method by etching and a forming method by mechanical engraving. In the present invention, among the plurality of gravure printing plates described above, a printing plate mainly for printing a character is etched by a printing method. , And the remaining key plate, red plate, and eye plate are formed by mechanical engraving. In the present embodiment, only the stencil plate is formed by etching, but a part of the remaining stencil plate may be formed by etching in addition to the stencil plate. Here, a forming method by etching and a forming method by mechanical engraving will be described.

There are a conventional method, a net gravure method, and the like as a forming method by etching. When the conventional method is described, first, a carbon tissue is adhered to a gravure screen and printing is performed. As a result, the portion corresponding to the white line of the screen is baked, and a cross-linked hardening line is formed on the gelatin surface of the tissue, and the black square portion of the screen is not hardened because light does not reach. Next, when a continuous tone positive is printed on the tissue, the squares of the resulting photosensitive material are hardened thinly or thickly according to shading. Then, when transferring the baked carbon tissue to the cylinder twice by using a transfer machine manufactured by Walter, the first time, a 0.20 mm polyester film was provided as the thickness adjusting film 4 as shown in FIG. Transfer, a second transfer without a thickness control film as shown in FIG. 2, then develop the cylinder, then erosion the surface with ferric chloride solution to further increase the press life This is a method of making a plate by chrome plating.

On the other hand, the forming method by mechanical engraving uses an apparatus such as that sold under the name of Heliocrisograph of Hell Co., and uses a continuous tone negative using a white opaque base as an original, scans it, and shades it. Is converted into an electric signal to finely vibrate the diamond needle in the engraved part, and engraving the surface while rotating the cylinder to make a plate.

The above-described plate making methods are well-known except for the register adjustment method in the transfer of the etching method. If the base of the carbon tissue used for forming the plate by etching is paper, it easily expands and contracts, which may cause misregistration with the plate formed by mechanical engraving. Therefore,
It is preferable to use a pigment film having a polyester base (for example, an auto film manufactured by Auto Type Co., Ltd.) in place of the carbon tissue.

Using the gravure printing plate for four colors obtained as described above, gravure printing was performed with four color inks of red, red, eye and sumi. The tone of the pattern was stable by the plate formed by the machine engraving method. While obtaining the character, it is possible to reproduce characters with good resolution by the plate (Sumi plate) formed by the etching method, and also to obtain sufficient sharpness of the pattern, and to obtain good balance as a whole Was able to print the printed matter.

Example 2 A color photo manuscript was scanned with a color scanner (Y),
Color separation for four colors of red (M), eye (C), and sumi (BK) was performed to output a net negative for lithographic printing. After performing the necessary retouching work on the screen negative, a screen positive for planographic printing was obtained by reversal processing. This mesh positive was arranged according to a predetermined layout and was pasted on a transparent film, and Japanese characters by typesetting were pasted for the Sumi version. In this case, the size of the character was 8 points, and a number with a large number of strokes was included. The screen positive thus obtained was printed on a PS plate, which is a plate material for offset, to produce a proof print by an offset printing method. With this proof printing, the tone, color scheme, characters and the like were confirmed.
Next, among the net positives, the three colors of yellow, red and eye were exposed to a photosensitive film (Lumilite, trade name, manufactured by Oriental Photo Industry Co., Ltd.) and developed to obtain a net negative. This is a reflection type negative. This is a Heliocrissograph (product name) manufactured by Hell
Attached to the original cylinder of a mechanical engraving device called
A halftone negative image was input, halftone dots were blurred electrically, and then mechanically engraved on a gravure cylinder with an engraving needle at the output unit to obtain a gravure printing plate having pyramidal cells. In this case, there were three gravure printing plates formed by mechanical engraving, i.e., yellow (Y), red (M), and eye (C).
On the other hand, with regard to the printing plate, a gravure printing plate was obtained by an etching method as follows. First, a gravure screen was closely adhered to a pigment film and a latent image for forming a dent for supporting a doctor blade was formed. After removing the gravure screen, a net positive for a stencil was closely adhered to the same pigment film. As shown in FIG. 6, only the surface corresponding to the second transfer of the second transfer is a thickness adjusting film between the film original (mesh positive film) 7 and the holding plate 5 of the pigment film 3 when the mesh positive is printed in close contact. 4 (about 0.15m
m) was performed. The pigment film obtained by baking the gravure screen and baking the net positive for the Sumi plate twice as described above is transferred to a gravure cylinder, developed with hot water, and etched with a ferric chloride solution to perform gravure. A printing plate was obtained.

Using the gravure printing plate for four colors obtained as described above, gravure printing was performed with four color inks of red, red, eye, and sumi. It has a stable tone reproduction with good balance of keys, reds and eyes, good reproduction of characters of the plate formed by etching and sufficient resolution, and a printed matter with good registration is obtained.

Example 3 A lithographic net negative for color separation of four color images of color (Y), red (M), eye (C), and sum (BK) was output from a color photo original using a color canner. After performing the necessary retouching work for the screen negative, a screen positive for planographic printing was obtained by reversal processing. This mesh positive is arranged according to a predetermined layout and pasted on a transparent film,
For the Sumi version, Japanese characters by typesetting were pasted. In this case, the size of the characters was 8 points, and also included kanji with many strokes. The screen positive thus obtained was printed on a PS plate, which is a plate material for offset, to produce a proof print by an offset printing method. With this proof printing, the tone, color scheme, characters and the like were confirmed.
Next, among the net positives, for three colors of yellow, red, and eye, a photosensitive film (manufactured by Oriental Photography Co., Ltd., through a matte sheet for diffusing light)
(Trade name: Orinapeque) and exposed to light to develop a substantially continuous tone negative with blurred halftone dots. This is a reflection type negative.

When printing on the photosensitive film, only the surface corresponding to the first transfer of the plate by etching, as shown in FIG. 8, the net positive 7, the surface mat-like sheet 15, and the photosensitive film 14 Positioning between the mat-shaped sheet 15 and the margin of the photosensitive film 14 (such as register pin holes) with a thickness adjustment film (0.15 mm) 4 in close contact exposure, and the positional relationship with the plate formed by etching Was adjusted. Except for the first transfer, the thickness adjusting film 4 in FIG. 8 was removed and exposure was performed in close contact.

This is attached to a manuscript cylinder of a machine engraving device called Heliocrissograph (trade name) manufactured by Hell, and after inputting a negative image, mechanically engraving the gravure cylinder with the engraving needle of the output unit, A gravure printing plate having pyramidal cells was obtained. In this case, there were three gravure printing plates formed by mechanical engraving: yellow (Y), red (M), and eye (C). On the other hand, for the Sumi plate, etching was performed in substantially the same manner as in Example 2, but gravure printing was carried out by a normal method without using the thickness adjusting film 4 of the present invention when the net positive was closely adhered to the pigment film. Got a version.

Using the gravure printing plate for four colors obtained as described above, gravure printing was performed with inks of four colors, i.e., red, red, eye, and smear. In the light part, moire was not conspicuous, and there was no roughness. Thus, a gravure print having a sufficient thickness of the print density in the halftone portion to the shadow portion and having a good tone over the entire portion from the light portion to the shadow portion was obtained. Furthermore, the reproducibility of the characters of the printed matter thus obtained is also good. It had a sufficient resolution.

<Effect of the Invention> In the gravure printing method of the present invention, since at least one plate is formed by etching and the other plate is formed by mechanical engraving, both advantages are utilized, and the tone stability is excellent,
In addition, a well-balanced printing section with good reproducibility of fine lines such as characters can be obtained.

In addition, printed matter with good registration accuracy of the plate formed by etching and the plate formed by mechanical engraving can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a transfer state of the present invention, FIG. 2 is a partial sectional view showing a second transfer state, FIG. 3 is a partial sectional view showing a first transfer state, and FIG. FIG. 5 is a development view of a plate cylinder, FIG. 6 is a partial cross-sectional view showing a state in which a carbon tissue or a resist film of the present invention is adhered and baked, and FIG.
FIG. 7 is a partial cross-sectional view showing a situation in which the photosensitive film of the present invention is being closely adhered, and FIG. 8 is a partial cross-sectional view showing a situation in which the photosensitive film corresponding to Example 3 is being closely adhered.
9a is an explanatory view showing the shape of a cell of a gravure printing plate formed by an etching method, FIG. 9b is an AA cross-sectional explanatory view thereof, and FIG. 10a is a gravure printing plate formed by a mechanical engraving method. FIG. 10b is an explanatory view showing the shape of the cell, and FIG. 1 ... transfer roller 2 ... cylinder 3 ... photosensitive sheet for plate (carbon tissue, pigment film, etc.) 4 ... thickness adjustment film 5 ... holding plate 6 ... picture by page 7 ... film original plate (bon 8) Glass 9 Light source 10 Optical device 11 Register pin 12 Cell 13 Cell 14 Photosensitive film 15 Matte sheet

Claims (3)

(57) [Claims] In a gravure printing method using a plurality of plates in which a plate formed by mechanical engraving and a plate formed by etching are combined, at least one plate is formed by etching. Transfer is performed a plurality of times in the circumferential direction, but the positional relationship shifts between the first and second times,
Since the circumference is not precisely divided equally, the registration of the plate formed by the mechanical engraving and the plate formed by the etching is performed. A gravure printing method, wherein the gravure printing method is performed differently between the first and second times. 2. In a gravure printing method using a plurality of printing plates in which a printing plate formed by mechanical engraving and a printing plate formed by etching are combined, at least one printing plate is used. Transfer is performed a plurality of times in the circumferential direction, but the positional relationship shifts between the first and second times,
Since the circumference is not exactly divided equally, the registration of the plate formed by the mechanical engraving and the plate formed by the etching is performed when the film original is printed on the photosensitive sheet for the plate during the etching process. A gravure printing method, wherein a gravure printing method is performed by placing a spacer between a plate holding a surface and a film master. 3. A gravure printing method using at least one plate formed by combining a plate formed by mechanical engraving and a plate formed by etching, wherein the plate is formed by etching. Transfer is performed a plurality of times in the circumferential direction, but the positional relationship shifts between the first and second times,
Without precisely dividing the circumference into equal parts, the registration of the plate formed by the mechanical engraving and the plate formed by the etching is performed by printing the film master during the mechanical engraving process onto the photosensitive film for mechanical engraving. A gravure printing method characterized in that a gravure printing method is carried out by placing a spacer between a holding plate and a film master on only the surface corresponding to the first transfer in the inside.