JPS5847356B2 - rotogravure printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotogravure printing apparatus, and more particularly to a multipage rotogravure printing apparatus in which page or double page size printing plates are printed on separate page or double page gravure printing plates. .

In currently used rotogravure printing, plates to be printed for multiple pages, e.g. pages 16, 20, 24, 28, are laid out and then etched or engraved onto the surface of a cylinder; Used in direct or offset printing to produce pagination.

After being printed, the multi-page printed paper is cut vertically and horizontally, folded, and assembled in a predetermined manner to create signatures.

The quires may be stapled together along one edge, as in a book, or left unbound.

The individual page plates are etched or carved into the surface of the cylinder so that the individual pages are in the correct order when the book is folded up and collated.

Therefore, the printed images of the valley-printed book of multiple page sizes are printed and become one page of the collated printed matter6. Providing a rotogravure cylinder for printing multiple pages representing the printed matter; Etching or engraving the cylinder is expensive, laborious, and inflexible.

Final plate page ordering must be performed before engraving or engraving onto the rotogravure cylinder can begin.

When engraving is done on a printing cylinder, changing one page often removes all etchings on all pages etched on that cylinder and requires re-plating. be.

Changes that would be desirable to make are often not made because of the time and expense involved.

Because of the expense and cheapness of preparing cylinders and the difficulty of making changes, rotogravure printing has been largely limited to long runs where a significant number of copies are printed without changes.

This was true even though rotogravure printing is very superior compared to other printing methods.

In addition to the expense of rotogravure printing, many of the problems that make rotogravure printing less flexible result from etching or etching multiple pages of printed content onto the surface of the rotogravure cylinder. arise.

In other types of multi-page printing, such as letterpress printing,
Difficulties similar to those described above have been overcome by utilizing page-sized printing plates.

The content to be printed is first created on a printing plate, and multiple such printing plates are loaded onto a printing drum.

However, in both lithography and letterpress printing, the method used to supply ink to the plate on a drum and to transfer the inked image from the printing drum to the receiving web is similar to the ink in rotogravure printing. The supply and transfer methods are completely different.

In letterpress printing, the image rises from the surface of the printing plate.

Ink is applied to the raised surface of the image,
Ink from this raised surface is transferred to the member being printed.

Because the image is raised in letterpress printing, any disturbance to the surface of the cylinder or drum, such as by the edge of the printing plate or by mounting elements for the printing plate, must be at the same level as the raised image surface or not. Unless there are taller protrusions on the surface of the cylinder or drum, printing will not be adversely affected.

Images in lithography are formed on the surface of a printing plate, cylinder or drum.

This is done by applying ink to the area of the surface where the image is applied and treating the surface to retain the ink for printing.

Lithographic inks are thick and viscous and hold up well when processed.

During printing, ink is transferred from such locations to the member being printed.

The ink is thick and viscous, and the unprocessed areas repel the ink, so there is no problem with ink being transferred from other areas.

Even if any amount of lithographic printing ink adheres to the area below the south face of the printing plate, the ink will not be transferred during printing due to its viscosity and density.
In lithographic printing, disturbances to the cylinder or drum surface, such as by the edge of the printing plate or by the mounts, have no adverse effect on the printing.

The rotogravure image is etched or engraved into the surface of the cylinder as described above.

Such etching forms shallow recesses on the surface of the cylinder.

In rotogravure printing, these recesses are filled with printing ink.

The cylinder is passed through a highly fluid ink tank,
Or such ink is darkened.

The ink is removed from the surface of the cylinder by the doctor blade but remains in the four parts.

Ink from the recesses is transferred to the surface of the member to be printed when that surface is brought into contact with the surface of the cylinder.

Unlike letterpress or lithography, in rotogravure printing the ink is deposited on and below the surface of the cylinder.

In order to apply ink to the recesses in the surface of the rotogravure cylinder, or to allow the cylinder to pass through the ink tank and under the doctor, it was previously possible to perform rotogravure printing using a removable page-sized printing plate. It could not be used for cylinders.

One of the problems that precludes the use of such printing plates is that they can be held in a fixed position on the cylinder during printing, and at the same time individual printing plates can be attached and removed. It is difficult to attach a plurality of printing plates to a cylinder so that the plates can be attached and detached.

Another problem is that ink builds up on the edges of the plates or in the gaps between the plates, resulting in undesired printing of the image, and as the edges of the plates pass under the doctor blade, the ink is removed. This may cause scattering or wear of the printing plate.

These and other problems that have hindered the use of printing plate units to perform rotogravure printing are overcome by the apparatus of the present invention.

According to the present invention, a printing plate for rotogravure printing is provided with a non-flexible backing member made of a magnetic material for mounting and holding a rotogravure printing plate in a fixed position on a magnetic cylinder; During rotogravure printing, the printing plate receives the printing ink in such a way that the image formed by the ink-receiving recesses on the surface of the printing plate is transferred to the ink-receiving surface on which the printing plate is rotogravure-printed. A rotogravure printing plate used for rotogravure printing is obtained, on which the recessed portions are formed.

When the printing plate is wrapped around a magnetic cylinder and attracted by magnetic air, the cylinder printing plate becomes a solid unit, much like if the image to be printed were etched or engraved directly onto the cylinder surface. Become.

The cylindrical plate forms a sturdy, integral unit because the ink image receiving member is brought into close contact with the cylindrical plate to produce properly aligned, high-quality prints. This is very important.

At the same time, one or more printing plates can be removed and replaced when one or more pages need to be changed.

This is very important because it allows such changes to be made without etching or carving the entire cylinder.

The time required for changes is greatly reduced and the costs involved are also significantly reduced.

Long run printing requiring the conversion of one or more printing plates during printing is also practical.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Referring first to FIG. 2, the printing plate 2 has a backing member 4 made of a magnetic material, such as steel, and a surface made of a material suitable for etching or engraving.

As the most commonly used surface material on rotogravure printing cylinders, copper has been found to be a particularly suitable material for etching or engraving surfaces.

Press plate 2 when handling or etching plate 2.
The printing plate 2 must have sufficient thickness so that it does not become distorted.

At the same time, the printing plate must not be so thick that it is impossible to match the curvature of the printing plate to the outer circumference of the magnetic cylinder.

Approximately 0.0 mm to perform etching or engraving. O051cr
/L (0.002 inch), about 0
．． Approximately 0 overall thickness with a copper surface not much thicker than 0.0076 crn (0.003 in.)
．． Not much thinner than 0.0203CrI'L (0.008 inch), about 0.0305crI
It has been found that printing plates not much thicker than L(0.0].2 inches) are satisfactory.

As best shown in FIG. 2, the copper surface 6 of the printing plate 2 is etched or engraved to form four parts 8, 11, 12.

The dimensions and depths of these four parts are shown enlarged in FIG.

In the practice of the present invention, the recesses are etched or carved in a conventional manner and with conventional dimensions, with the dimensions of those recesses measured in microns, and the opening size and depth determined according to the lightness and darkness of the tone to be printed at a particular point. It changes.

The surface 6 of the printing plate 2 can be etched or engraved when the printing plate 2 is flat, and then the printing plate 2 can be bent to match the curvature of the outer circumference of the magnetic cylinder. Once bent together, the copper surface 6 can be etched or engraved.

After etching, the surface of the printing plate 20 is plated with chrome to make the printing plate durable for long-term use.

As shown in FIG. 3, the printing plate 2 shaped according to the curvature of the cylinder 100 is brought into contact with the magnetized surface of the cylinder 10 by bringing the backing member 4 into contact with the magnetized surface of the cylinder 10. It is held tightly by being rolled up facing up.

The dimensions of the printing plate 2 can be varied depending on the dimensions of what is to be printed.

The printing plate 2 is matched to the surface of the cylinder 10.

Therefore, when the printing plate 2 is loaded onto the surface of the cylinder 100, the printing plate 2 covers the surface of the cylinder 100, which would otherwise receive a smeared ink image.

The plate 20 dimensions are preferably I-page sized so that during rotogravure printing, adjacent edges of the plate 2 contact the member receiving the ink image during one printed page.

Bending the printing plate 2 and magnetically fixing it to the surface of the magnetic cylinder 10 so that the page is printed from top to bottom, bottom to top, or side to side depending on the page layout of the member to be printed. I can do it.

In any case, as shown in FIG. 3, the leading and trailing edges of adjacent printing plates across the cylinder in the axial direction form a certain angle, for example, 5 degrees, with respect to the axis of rotation of the cylinder 100. Shaped or cut.

As will be explained in more detail below, for some rotogravure printing the adjacent edges of the printing plate 2 can be filled with filling elements 13 (FIG. 4).

Compatible with the material of the printing plate 2 and cylinder 10, not soluble in printing ink, resistant to abrasion, non-porous, can be applied as a thick fluid or glue, and cures flat and smooth, such as an epoxy resin. Fast drying materials are suitable for use as filler materials.

As shown in FIGS. 5 and 6, the magnetic cylinder 10 to which a plurality of printing plates 2 are magnetically attached can be used for direct rotogravure printing (FIG. 5) or offset rotogravure printing (
(Fig. 6).

First, referring to FIG. 5, a magnetic cylinder 10 to which a printing plate 2 is magnetically attached is attached to a frame 20 of a rotogravure printing press and rotated in the direction indicated by the arrow.

An impression cylinder 22 having a surface 24 made of a resilient material such as rubber is mounted on the frame 20 and rotated in the direction indicated by the arrow.

A web 26 of paper-like material is fed between the printing plate 2 and the impression cylinder 22 on the cylinder 10 in the direction shown by the arrow.

While the web 26 moves between the printing plate 2 and the impression cylinder 22, ink from the recesses facing the web of the printing plate 2 is transferred to the web 26 and printed on the web 26 to form the desired image. form an image of

In order to reduce the pressure exerted on the resilient surface of the impression cylinder 22 under the printing plate 20 gap during printing, that part can be cut down.

In the embodiment shown in FIG. 5, the magnetic cylinder 10 passes through an ink bath 28 while rotating in the direction indicated by the arrow.

The ink adhering to the surface of the printing plate 20 is removed by the doctor 30, leaving ink only in the recesses 8, IL12, etc.

The ink is removed from the surface of the printing plate 20, and the recesses 8, 10, 12 are
In the embodiment shown in FIG. 5, the doctor blade 30 which leaves ink in the gaps between printing plates 20 also acts to leave ink in the gaps unless the gaps are filled with filler material 13.

The ink left in the gaps not filled with filler transfers the ink image from the printing plate 2 to the web 26 when the web 26 contacts the gap in the printing plate.

Due to the dimensions of the printing plate and the location of the gaps between the pages, the ink images printed by the gaps are cropped from the pages if those pages are to be cropped.

As mentioned above, the gaps in the printing plate can be filled with filler material 13 to eliminate the gaps, thereby eliminating the printing of images of the gaps.

In this case, there is no need for trimming.

In the embodiment of offset rotogravure printing shown in FIG. 6, the magnetic cylinder 10 is attached to the frame of the printing press 32 and rotated in the direction indicated by the arrow.

A transfer cylinder 34 and an impression cylinder 38, covered by an offset 1 blanket 36, are mounted on the frame 32 and rotated in the direction shown by the arrow.

A web 40 of paper-like material is fed between the blanket 36 and the impression cylinder 38 above the transfer cylinder 36.

In the offset rotogravure printing machine shown in FIG.
When the cylinder 10 and the printing plate 2 pass under the doctor 44, the ink is removed from the surface of the printing plate 20.

When the cylinder 10 rotates, the recesses 8, 11, 12 of the printing plate 2
The ink inside is transferred to the blanket 36 of the transfer cylinder 34.
The web 40 on the impression cylinder 38 is transferred to the blanket 36.
The force is transferred from the blanket 36 to the web 40 upon contact with the web 40.

As shown in FIG. γ, in the embodiment of offset printing shown in FIG.
It is better to cut off the part facing the gap between.

In this case, it is not necessary to fill those gaps with the filler 13 shown in FIG. 4 or the like.

In FIG. 7, the blanket 36 is cut off in the axial direction of the cylinder 10, as indicated by reference numeral 50, and in the circumferential direction of the cylinder 100, as indicated by reference numeral 52.

The cutout 50 can be slightly angled to match the angle of the leading and trailing edges of the printing plate 2, and be wide enough to accommodate the edges of the printing plate that are bent during printing. can have.

Cut-outs 50, 52 are arranged on the printing plate so that when printing plate 2 on cylinder 10 contacts blanket 36, the gap between printing plates 20 does not contact blanket 36, but rather is spanned by the cut-out portion of blanket 36. Reprinted to version 2.

Therefore, ink that may accumulate in the gaps is not transferred to the blanket 36.

This prevents ink from the gap image from the printing plate 2 on the magnetic cylinder 10 from transferring to the blanket 36 of the transfer cylinder 34, and such a gap image from being printed on the web 40.

In the present invention, the printing plate 2 is held at a fixed position on the magnetic cylinder 10 by the magnetic attraction between the magnetic cylinder 10 and the magnetic backing member 6.

The valley printing plate is held on the cylinder 10 independently of the other printing plates.

Therefore, individual printing plates can be attached and removed without interfering with other printing plates on the cylinder 10.

When the gap between adjacent printing plates is filled with filler, replacing the printing plate involves removing the filler and the printing plate to be replaced, inserting a new printing plate, and filling the gap with filler again. do.

By removing and replacing individual printing plates without removing other printing plates, the content of the image to be printed can be partially changed.

Such partial changes in content are very important in newspapers, magazines, etc. where small changes in content are made between editions for distribution to different regions.

When the printing plate 2 of the invention is used in a rotogravure printing press, the leading and trailing edges are cut or formed at an angle, for example about 5 degrees.

Place printing plate 2 into cylinder 1 with minimum gap between printing plates 2
The angled leading and trailing edges are parallel and all plates are cut at the same angle so that they can be assembled around the 0.

The side edges of the printing plate are parallel to each other, and when it is attached to the magnetic cylinder 10, it is in the rotation direction of the cylinder 100.
The side edges of the printing plate are cut off.

The angular positioning of the leading and trailing edges of the plate 2 on the cylinder 10 prevents the doctor from being shocked when the cylinder 10 rotates and the gap passes under the doctor.

The doctor can be placed at an angle to the cylinder 10 rather than at an angle to the edge of the printing plate.

This arrangement is particularly important when the gap between adjacent edges is not filled with filler material, since it prevents ink splatter and doctor blade wear.

If the gap is filled, uneven wear of the doctor blade on the printing surface formed by the printing plate surface and the filling material surface is prevented, especially when long rotogravure printing is carried out. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a printing plate used in the present invention, and Fig. 2 shows ink receiving recesses formed by etching or engraving in the surface of a printing plate for rotogravure printing. 3 is a perspective view of a rotogravure printing cylinder in which the printing plates shown in FIGS. 1 and 2 are attached, and FIG. FIG. 3 is an enlarged view along the line 4-4 of FIG. 3 showing an embodiment filled with material, FIG. Figure 7 is a perspective view of an undercut blanket roll used as a transfer roll in the embodiment shown in Figure 6; 2...Printing plate, 4...Backing member, 6...
...Surface, 8, IL12...Ink holding recess, 10. ．． ．． ．． ．． ．． Magnetic cylinder, 22...-
・Impression cylinder, 24...Elastic surface, 26, 40...
... Web, 28, 42 ... Ink tank, 30,
44...Doctor 34...Transfer cylinder.

Claims (1)

[Claims] 1. A rotogravure printing machine having a magnetic cylinder, an impression cylinder, and a printing plate that is magnetically attached to the magnetic cylinder and shaped to match the surface of the cylinder. A rotogravure printing machine characterized in that the valley edges of the valley printing plate extending in the axial direction of the cylinder are parallel to each other and arranged at an angle of about 5 degrees with respect to the axis of the cylinder. . 2. Form a plurality of longitudinal cut-off portions and a plurality of circumferential cut-off portions in the same area as the seam between the printing plates on the elastic surface of the impression cylinder, and form a plurality of longitudinal cut-off portions in the same area as the joint between the printing plates, and form a plurality of cut-off portions in the circumferential direction. extends the entire length of the resilient surface and has a width sufficient to cover the longitudinal seam of the printing plate, and each circumferential cutout extends over the entire circumference of the resilient surface. and having a width sufficient to cover the circumferential seam of the printing plate, the cut-off portion being of a width sufficient to cover the circumferential seam of the printing plate, such that the cut-off portion is 2. A rotogravure printing press according to claim 1, wherein ink transfer at the seam is minimized by aligning with the seam and minimizing pressure at the seam.