FR2705054A1 - Printing process stamped on a printing machine, such as an offset press, and device for its implementation. - Google Patents

Abstract

The invention relates to a method for the stamped printing of sheets of paper or card on a printing press (1), comprising a press cylinder (3) and a plate cylinder (4) of parallel axes. Prior to passing sheets between the cylinders (3, 4), a thin plate (13) covered with a photopolymer layer is fixed around the plate cylinder (4), on which layer is formed a pattern in relief and inside out, and the plate cylinder (4) is forcibly applied against the press cylinder (3) then, in order to print one face of the sheets (17b) as an impression, each sheet (17b) of paper or card is engaged between the cylinder (3, 4). The invention also relates to a device for the implementation of such a method.

Description

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  The present invention relates to a printing process stamped sheets of paper, cardboard or the like on a printing machine, such as an offset press, and a device for its implementation. It is known to emboss sheets of paper or

  cardboard on typographic presses.

  For this purpose, three embossing devices, described below, are commonly used to form patterns in relief and recessed on

sheets of paper or cardboard.

  A first embossing device comprises a two-roll rotary press of parallel axes between which is engaged a strip of paper or cardboard, and two storage coils on which is wound the paper or cardboard strip downstream and upstream of the press. One of the cylinders has a pattern engraved in relief on its surface and the other

  cylinder may have on its surface the same pattern engraved intaglio.

  The rolls are compressed against each other along their common generator to emboss the engaged web. This device has many disadvantages, including a very high cost, because it is necessary to engrave a different cylinder for each new pattern,

  not to mention that the cost price of a single engraved cylinder is very high.

  As a result, in practice, a uniform embossing of the entire web is performed to use the same engraved cylinder for different uses of the web. Even if partial embossing of the web surface in a particular pattern, i.e., the web has non-embossed locations commonly referred to as "windows" or "reservations", it is very difficult to cut the band accurately because the location on it may vary a few centimeters. However, this division is necessary if we want to apply

  later colors or characters on the embossed sheet.

  So we do not always get an exact superposition of characters and colors with the previously embossed parts and

  reserved of the precut sheet.

  A second embossing device comprises a press with two flat platens, a first platen being fixed and supporting on one side embossed plates, and the second platen being articulated laterally in rotation on the first plate being adapted.to compress

  the plates of the first plate.

  The turntables are fed sheet by sheet, each sheet

  being embossed by the plates engraved during the compression of the plates.

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  The speed of manufacture by this alternative embossing device is much slower (about 1,500 sheets per hour on average) than the previous device, because in the latter, the press is fed by a scrolling strip. The cost price of each embossed sheet is increased. In addition, the second embossing device requires the use of engraved plates of great thickness, for example brass, copper or zinc, whose unit cost is very high. In addition, you must engrave a different plate for each new pattern. Finally, because of the large contact area of the plates, it takes a very great pressure to deeply emboss a cardboard sheet, and often several passages, of the order of six, are necessary to perform the embossing, resulting in a overtime, and a waste of time. The two-deck devices do not usually have enough pressure to achieve in one

  passing a deep embossing of a cardboard sheet.

  A third embossing device comprises a rotary with a cylinder, the cylinder being able to come and compress a plane plate. This device is also fed sheet by sheet, each sheet winding on the upper part of the cylinder, and engaging between the

  lower part of the cylinder and the plate.

  Embossed plates are mounted on the face of the plate which is compressed by the cylinder. The plate performs a horizontal translation movement perpendicular to the axis of the cylinder, in order to

emboss the leaves.

  The speed of manufacture by this alternative device is slightly faster than the previous device (about 2,000 sheets per hour on average), but still significantly slower than by

the first embossing device.

  In addition, surprisingly, the pressure necessary to achieve a deep embossing of a cardboard sheet remains very high, and

  several passages are also necessary to perform the embossing.

  In this device, plates engraved with

  great thickness and consequently very expensive.

  It is known to deposit on a printed sheet or not, a film, such as a gilding or a color. This technique is generally known by the name of "gilding" and is generally carried out using the last two embossing devices, described above, by unrolling the film in front of the embossed plates. The film is deposited on the sheet by hot pressing the two plates or platinum

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  and the cylinder. During the laying of the gilding, the speed of manufacture is further reduced because the presses have to be broken up to change the film reels when they are exhausted, and thus fall at an average speed of manufacture of about 1,200 sheets per hour for the second device and about 1,500 sheets per hour for the third device. In conventional embossing processes, the sheets of paper or board undergo stresses which lead to the formation of "micro-cracks" at the folds of the sheet and to

deformation of its dimensions.

  The initial mechanical qualities of the sheet are therefore altered and the subsequent operations, in particular cutting, hot stamping and packaging, are made with difficulty because the marking of the printed pattern loses its precision and the friction of the sheet on the sheets.

  different machines vary from sheet to sheet.

  The object of the present invention is to provide a method and a stamped printing device which allows to print on one side, in the surface layer of a sheet, the most diverse patterns at a low cost, with great simplicity and speed, and which avoids the aforementioned disadvantages of the methods of

embossing classics.

  Another object of the invention is to provide a method and a stamped printing device for printing intaglio and

  to trace an ink simultaneously on the same machine to print.

  The present invention relates to a printing process stamped sheets of paper, cardboard or the like, on a printing machine comprising a pressure cylinder and a plate cylinder of parallel axes, characterized in that, previously as the sheets pass between the rolls, a thin plate covered with a photopolymer layer is formed around the plate cylinder on which is formed a pattern in relief and upside down, and the cylinder plate against the pressure cylinder, then to imprint a face of the sheets, we engage each sheet of paper or cardboard

between the cylinders.

  This embossed printing process, unlike the embossing methods already known, allows to print in hollow only the front face or

  back of the sheet which is at the right of the thin plate.

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  Thus, only the first layer or the surface layer of a face of the sheet is deformed during the stamped printing, which

  does not alter or very little initial mechanical qualities of the sheet.

  The risks of "micro-cracks" are also reduced because only the first layer of one side of the sheet is compressed. Not subjected to dimensional deformations, the leaves can be perfectly marked for the subsequent operations and the passage of the leaves on automatic machines is made reliable by the fact

  that the friction of the leaves on the machines remain constant.

  The plate is usually made of steel, aluminum, plastic or

in a mixture of these.

  In order to obtain a pattern in relief on a plate, the following operations are carried out in sequence: a uniform layer of a lacquer based on photosensitive polymer resins is deposited on the plate, a negative mask is deposited on the plate to form the relief pattern and illuminate the photopolymer layer in ultraviolet light

through the mask.

  The unmasked areas of the photopolymer layer polymerize

under sunstroke.

  then, to develop the plate, the unpolymerized resin is dissolved in a selective solvent in a "etcher" and the photopolymer layer is rinsed with water to evacuate the non-insolated zones of the

photopolymer layer.

  According to the present invention, an ink, such as a color or a matt or glossy varnish, is advantageously deposited on the thin plate by means of inking rollers, for intaglio printing and tracing.

  simultaneously a pattern on the leaves.

  The present invention may in particular and advantageously be implemented on an offset press comprising inking rollers, a blanket cylinder constituting the plate cylinder, a second

  plate cylinder and a pressure cylinder.

  Unlike conventional use of the offset press, in the present invention, the blanket cylinder is

  thin plate covered with a photopolymer layer, instead of a blanket.

  To print the leaves, it is not necessary to use

  the plate cylinder of the offset press and the inking rollers.

  To imprint a pattern on leaves, it is thus used, so

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  Quite unexpectedly, an offset press usually intended to be traced

ink.

  Advantageously, prior to the passage of the sheets, is fixed further around the second plate cylinder a printing plate on which is formed a pattern at the place, and then deposited an ink, such as a color or a varnish, on the printing plate with the inking rollers, and the ink is decal on the thin plate, to indent the pattern on the sheets and to simultaneously

color or varnish.

  In a particular embodiment of the invention, each of the two opposite edges of the thin plate covered with a photopolymer layer or of the printing plate is fixed in the jaws of a wedging bar and one mounts each locking bar on the cylinders

blanket or plate holder.

  An ink, such as a color, a varnish or characters, can be traced on the sheets, both before or after printing.

  hollow according to the embossed printing method of the present invention.

  In the same way, a film, such as a gilding or a color, can be deposited by hot pressing on the sheets, both before and after the intaglio printing according to the stamped printing process of the

present invention.

  Advantageously, the intaglio printing takes place in a single passage of each sheet between the cylinders, unlike the devices

embossing known.

  In a particular embodiment of the invention, several identical reproductions of the pattern which are to be printed in the hollow on the sheet are formed in relief on the plate, since pressure is available.

  sufficient to print in one pass all the patterns reproduced.

  During a usual ink decal on sheets using an offset press, the blanket cylinder and the pressure cylinder

barely touch each other.

  For example, for a pressure cylinder of length equal to about 1 meter, and having a crushing width of about 10 mm, a pressure equal to 20 kg / cm 2 is exerted between the blanket cylinder and the pressure cylinder. 'that is to say a pressure force equal to

about 20 KPa.

  To print hollow leaves, this pressure is generally doubled.

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  The present invention also relates to a printing device stamped with sheets of paper or cardboard for the implementation of the method described above, characterized in that it comprises a pressure cylinder, a plate cylinder , a thin plate covered with a photopolymer layer in which a pattern is formed in relief and upside down, means for fixing the plate around the plate cylinder and adjustment means for applying the cylinder

  plate holder against the pressure cylinder.

  Advantageously, the embossed printing device comprises in

in addition to the inking rollers.

  To better understand the invention, will be described below, by way of purely illustrative and non-limiting, an embodiment shown in the accompanying drawing in which the single figure is a schematic side view of the device. stamped printing

the present invention.

  The figure represents an offset press 1 comprising a frame 2 in which a pressure cylinder 3 is mounted, articulated in rotation about parallel axes, a blanket cylinder constituting a first plate cylinder 4, a second cylinder carrying plate 5 and two driving rollers 6. In the vicinity of the upper part of the plate cylinder 5 is mounted an inking assembly 7. The ink set 7 comprises a plurality of inking rollers 7a and a lever 7b adapted to put the inking rollers 7a are in contact with the upper part of the plate cylinder 5. The inking rollers 7a contain ink, such as matt or glossy colors or varnishes. A moistener assembly 8 is in the vicinity of a side portion of the platen cylinder 5. The moistener assembly 8 comprises damping rollers 8a and a lever 8b adapted to put the rollers in contact with each other.

  moisturizers 8a with the lateral part of the plate cylinder 5.

  Generally, the wet rollers 8a contain water.

  Two levers 9 and 10 make it possible respectively to move the blanket cylinder 4 and the plate cylinder 5 in the vertical direction in order to adjust the bearing pressure between these two cylinders and the

pressure cylinder 3.

  The blanket cylinder 4 and the plate cylinder 5 each comprise two blocking bars 11 and 12 respectively.

  Shim bars 11 and 12 have jaws.

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  A thin plate 13 covered with a photopolymer layer in which a pattern is formed in relief and upside down, is fixed around the

  blanket cylinder 4 in the jaws of the wedging bars 11.

  During the usual use of the offset press 1, a blanket, not shown in the figure, is fixed around the blanket cylinder 4 in place of the thin plate 13, in order to achieve a

double decal of the ink.

  A thin plate 14 covered with a photopolymer layer in which a pattern is formed in relief and at the location, is fixed around the plate cylinder 5 in the jaws of the clamping bars 12. This thin photopolymer plate 14 can be replaced. by a printing plate on which is formed a planar pattern and at the location having a more sensitive and more ink receptive printer part which is a greasy liquid, and a non-printer more receptive part to the water which is liquid

  skinny. In this case, it is necessary to use the moistener assembly 8.

  A guide mat 15 is wound around the drive rolls 6, and comprises three gripping members 16 regularly spaced, such as clamps, in which is clamped the downstream end of a printed sheet 17a. The printed sheets 17a are driven by the gripping members 16 by rotation of the driving rollers 6

around their axis.

  A gripping member 18, such as a gripper, is mounted on the surface of the pressure cylinder 3 and said gripping member 18 can

  tighten the downstream end of a sheet 17b not yet printed.

  A sensor 19 is mounted slightly upstream of the pressure cylinder 3 in the vicinity of the place where the downstream end of the sheet 17b

  not yet printed is clamped by the gripping member 18.

  A margin table 20, slightly inclined relative to the horizontal, is upstream of the pressure cylinder 3. The upstream end of the margin table 20 is at a level slightly higher than that of its downstream end, which facilitates the translational movement of the sheets 17b to the pressure cylinder 3. For this purpose, the margin table 20 comprises drive belts not shown in the figure. A locating tab 21 serves as a stop for the sheet 17b and measures its placement so that the pattern of the plate 13 is superimposed

  perfectly with the pattern already printed on sheet 17b.

  A feeder 22 is mounted on the frame 2 in the vicinity of the upstream end of the margin table 20. The feeder 22 has two members

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  sucker 22a, able to move in horizontal translation between a first stop position, in which the two suction members 22a respectively grip the downstream end and the center of a sheet 17b on the top of a stack of sheets stored on a vertically sliding plate (24), and a second stop position, in which the sheet 17b is deposited on the upstream portion of the margin table 20. The feeder 22 further comprises a lever 22b adapted to engage the organs

Suction cup 22a with the battery 23.

  A carriage 25 provided with a stop 25a is directly above the part of the belt 15 which is suspended between the two cylinders

Training 6.

  The printed sheets 17a are deposited in the carriage after being released by the gripping members 16 when the latter

  arrive at the vertical of the abutment 25a.

  A guiding means 26 is mounted under the lower portion of the belt 15 to support and guide the leaf 17a until it is clear.

  still deposited in the carriage 25.

  The operation of the device according to the invention is as follows: The feeder 22 grasps a sheet 17b on the stack 23 of sheets and deposits it on the margin table 20. The sheet 17b is driven onto the margin table 20 by means of belts drive to the locating cleat 21. Then, the sheet 17b is clamped by the gripping member 18 when the sensor 19 detects the presence of the downstream end of the sheet 17b in the vicinity of said gripping member 18. The cylinder pressure 3 then drives, in rotation about its axis, the sheet 17b which is engaged between the pressure cylinder 3 and the blanket cylinder 4 on which the thin plate 13 covered with a photopolymer layer has previously been mounted . The sheet is intaglio printed, and optionally ink is transferred there during its passage between the rolls. Then the printed sheet 17a is gripped by a gripping member 16 mounted on the belt 15 wound around the two driving rollers 6. The driving rollers 6, by rotation about their axis, cause the printed sheet 17a to the vertical of the carriage 25 o the printed sheet 17a is released by the body of

  gripping 16 when it is vertical to the abutment 25a.

  In a variant not illustrated, it is possible to use. an offset press comprising a plurality of blanket cylinders 4, a plurality of plate cylinders 5 and / or a plurality of inking rollers 7 cooperating with

the same pressure cylinder 3.

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  In another variant not illustrated, it is possible to use a printing machine comprising only a pressure cylinder and a plurality of plate cylinders on which inking rollers can

possibly apply.

  In yet another variant not illustrated, it is possible to use a printing machine comprising a single pressure cylinder cooperating on the one hand with a blanket cylinder and a plate cylinder for the ink decal, and on the other hand, with a plate cylinder for

intaglio printing.

  Although the invention has been described in connection with a particular embodiment, it is obvious that it is in no way limited thereto, and that many variations and modifications can be made to it without

  however, out of his frame or his mind.

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Claims (7)

  A stamped printing process of sheets of paper or cardboard on a printing machine (1) comprising a pressure cylinder (3) and a plate cylinder (4) with parallel axes, characterized in that, prior to the passage of the sheets between the rolls (3, 4), a thin plate (13) covered with a photopolymer layer is formed around the plate cylinder (4) on which is formed a relief pattern and upside down , and the plate cylinder (4) is applied against the pressure cylinder (3) by force, then to imprint one side of the sheets (17b), each sheet (17b) of paper or cardboard between the cylinders (3,4).   Stamped printing process according to Claim 1, characterized in that an ink, such as a matte or glossy color or varnish, is deposited on the thin plate (13) by means of inking rollers. (7), for intaglio printing and simultaneously tracing the pattern on leaves.   3. Embossed printing method according to any one of   Claims 1 and 2, characterized in that the printing machine is an offset press (l).   The embossed printing method according to claim 3, wherein the offset press (1) comprises a second plate cylinder (5) characterized in that, prior to the passage of the sheets, is fixed further around said second cylinder plate holder (5) a printing plate (14) on which a pattern is formed at the location, and then an ink, such as a color or a varnish, is deposited on the printing plate (14). ) by means of the inking rollers (7) and the ink is transferred to the thin plate (13) to impress the pattern and   tracing the ink simultaneously on one side of the sheets.   5. Embossed printing method according to any one of   preceding claims, characterized in that each of the   two opposite edges of the plate (13, 14) in jaws of wedging rods (11, 12) and each wedging bar (11, 12) is mounted on the cylinders (4,5).   6. Printing device embossed with sheets of paper or cardboard, for the implementation of the method according to any one of   preceding claims, characterized in that it comprises a   pressure cylinder (3), a plate cylinder (4), a thin plate (13) covered with a photopolymer layer on which a pattern is formed in relief and upside down, fastening means (11) of the plate 2705054 thin (13) around the plate cylinder (4) and adjusting means (9) for applying the plate cylinder (4) against the cylinder of pressure (3).   7. Embossed printing device according to claim 6, characterized in that it further comprises inking rollers (7).