WO2016062951A2

WO2016062951A2 - Method for printing common elements and at least one personalised element on a strip of paper

Info

Publication number: WO2016062951A2
Application number: PCT/FR2015/052796
Authority: WO
Inventors: Christian ROUVEROT
Original assignee: Sego
Priority date: 2014-10-20
Filing date: 2015-10-19
Publication date: 2016-04-28
Also published as: FR3027251A1

Abstract

The invention relates to a method for printing on strips of paper in rolls, comprising successively: inkjet printing of at least one personalised element on the strip of paper; offset heatset printing of common elements on the strip of paper; heat-drying of the strip of paper. The invention further relates to a printing line (10) for carrying out the method.

Description

Title: Common Element Printing Process and at Least One Custom Element on a Paper Tape

Technical field of the invention

The present invention relates to the technical field of rotary offset printing with thermal dryer on roll paper. More particularly, the present invention relates to the technical field of rotary offset printing with thermal paper dryer in coil for large-print documents comprising common elements and at least one customized element.

State of the art

The printing of large circulation documents such as newspapers, magazines, catalogs, etc. is often done by groups of presses from rolled paper strips. For this, the roll paper is unrolled by means of an unwinder and then passes between a cylinder (the blanket) and a roll (counter-pressure) of each of the offset printing units, each printing group. printing a color. After passing through the different groups of presses, the paper web passes through a dryer to dry the ink suitable for the thermal drying offset process, also known by its English name offset heatset.

This whole process makes it possible to print elements that are common to all the output documents.

Finally, once dried, the strip of paper passes through a cooler for cooling and then in a folder-cutting machine to shape the notebooks that will form the finished or semi-finished documents ready to be broached or distributed.

Customization may be provided to print personalized elements on the paper strip, such as a name, a sign, an address, a number for the numbered copies, etc. These custom elements can help with distribution or give more value to the print.

The printing of custom elements is done by inkjet printing at very high speed. The ink used for inkjet printing in this case is based aqueous. This is why the printing is done after the paper web has been dried and before the folder-cutter because the wetting of the paper during printing by the offset presses could alter the printing of the custom elements made in the printing press. the water-based ink. Generally, the inkjet printer is disposed above the cooler, and in particular on its first cylinder.

Despite the ease of realization of such customization, the overall print quality of these elements is not always up to expectations. Indeed several problems can arise during the complete cycle of printing of the common and personalized elements.

The addition of an inkjet printer in the printing line comprising groups of presses modifies the passage of the paper strip which requires recalibration of the printing line, in particular of the folder-cutting machine, when we go from printing with and without inkjet and vice versa. In addition, this modification by the addition of an inkjet printer can degrade the intrinsic reliability of the print line which has been specially optimized without taking into account this addition.

The paper strip is generalization carried on floating edge of the last group of presses to the dryer and the dryer to the folder-cutting machine, that is to say that the edges of the paper strip are not guided all along of the printing process. As a result, the paper web may shift before arriving at the inkjet printing station. This results in imprecision in the position of the custom elements on the paper web.

Moreover, because the paper web is successively and repetitively wet and dried as it passes through the rotary groups and the dryer, the paper web undergoes deformations: elongation during the wetting phases, shrinkage during drying phases. This results in a pleating where the custom elements have to be printed which then alters the quality of the inkjet printing.

Because the hydrophobic ink used for rotary printing comprises a solvent, this solvent evaporates as it passes through the dryer and surrounds the surface of the paper web as it exits, resulting in the formation of a layer of paper. air polluted by solvent residues around it. The presence of this layer of air Polluted can deteriorate the quality of inkjet printing because the projected water-based ink must pass through this layer of polluted air.

In addition, the area between the dryer and the folder-cutting machine, that is to say where the cooler is located, is a dust-laden area due to the different treatments that the paper web has undergone. These dusts come to foul print heads and oven of the inkjet printer thus increasing the frequency of their maintenance. This zone is also, because it is located near the dryer, at a high temperature that can degrade the functionalized inkjet printer.

Finally, this zone is generally very confined, that is to say that the space provided between the dryer, the cooler and the folder-cutting machine is very small. The arrangement of the inkjet printer at this location further reduces the present space for the operators to intervene on the print line to do so in good conditions. Presentation of the invention

An object of the present invention is therefore to overcome at least one of the disadvantages of the state of the art described above.

For this purpose, the present invention proposes a method of printing a rolled paper web successively comprising:

- the inkjet printing of at least one custom item on the paper strip;

thermal offset printing of common elements on the paper web;

- Thermal drying of the paper web. Thanks to this process, the quality of inkjet printing could be improved. Indeed, performing inkjet printing before printing with the presses has the following advantages:

the addition of the inkjet printer upstream of the rotary printing line makes it possible to overcome the need for calibration of the latter, in particular of the folder-cutting machine, when it is desired to switch from inkjet and non-inkjet printing, in other words, inkjet printing has no influence on the register; the paper strip is printed by inkjet at the exit of the unwinder, the risks of offset of the paper strip are therefore reduced the more accurate inkjet printing;

the strip of paper is printed by ink jet while it has not yet been wetted or dried, so there is no risk of printing on folds that would have formed, printing inkjet is not influenced by the hygrometry at the exit of the drying, by the layer of polluted air forming around the paper band, the presence of dust;

- Moreover, the inkjet printing is done directly on the blank paper; the inkjet printer is not likely to be degraded by the presence of dust or high temperature; and

the area between the spool and the first rotating group is generally less congested and thus allows the intervention of the operators on the inkjet printer easier, the fact that the drying is performed after the inkjet printing allows to benefit from an additional drying of the water-based ink used for inkjet printing, which also makes it possible to achieve an optimal printing speed without the risk of staining.

Thus, contrary to the teaching of the state of the art, providing inkjet printing before passing through the groups of presses does not reduce the quality of the inkjet printing but on the contrary the improved.

Other optional and non-limiting features are as follows.

In a particular embodiment, the printing method further comprises drying the paper web directly after the inkjet printing, and wherein the inkjet printing is performed with the aid of an aqueous ink.

Alternatively or additionally, the transport of the paper web is carried out on floating board.

Those skilled in the art will appreciate that these features can be combined. The present invention also proposes a printing line comprising successively in the running direction of a strip of paper:

- an inkjet printer for printing at least one custom item on a roll of paper tape; - a rotary printer for thermal drying offset printing of common elements on the paper web; and

- a main dryer to dry the ink deposited on the paper strip. This print line provides the same benefits as those described above. Other optional and non-limiting features are as follows.

In a particular embodiment, the print line further comprises an auxiliary dryer disposed between the inkjet printer and the rotary printer to at least partially dry the ink deposited on the paper web by the printer. Inkjet printer before passing the paper tape through the printer.

Alternatively or additionally, the printing line comprises a silicone group. Alternatively or additionally, the rotary printer comprises at least one printing unit.

drawings

Other objectives, characteristics and advantages will appear on reading the following detailed description with reference to the drawings given for illustrative and non-limiting purposes, among which:

FIG. 1 is a flowchart schematizing the various steps of the method according to the invention;

FIG. 2 is a diagram illustrating a printing line according to the invention enabling the method of FIG. 1 to be implemented.

Description

A method for printing large-size documents from a web of reel paper, in which common elements and at least one custom element are printed, is described below with reference to FIG.

It will be understood throughout this presentation the terms "common element" as a print item that must appear on each of the documents. A common element is in particular the content of documents intended to inform the future reader, such as an article for newspapers or magazines, a presentation of products for catalogs, etc.

It will be understood throughout this presentation the terms "custom item" as a print item that should not appear on all documents. Such an element appears only on a subgroup of documents, or even a single document. A personalized element can be for example a title (such as Mr, Mrs, Miss, Doctor ...), a name, a name, a sign, an address, an identifier, etc.

This process successively comprises:

- the inkjet printing of at least one custom item on the paper strip;

- rotary printing of common elements on the paper web;

drying the paper web.

Inkjet printing involves ejecting drops of ink to the paper strip. The drops are loaded or not. The drops can be deflected by the application of an electrostatic field or by an air jet. Usable inks generally include a dye dissolved in a solvent (often water giving a water-based ink). Other usable inks include solid pigments carried by a transparent and easily evaporable fluid. Inks may still be conductive inks composed of metal particles or conductive polymers.

Thermally-drying offset printing consists in passing the paper web between a roll and a roll, the roll forming the blanket conventionally formed by a rubbery material receiving ink from a plate cylinder (the printer form ) and transferring it to the paper, the paper guide roller acting as a back-pressure roll. Another roller serves to transfer the ink to the plate cylinder. An example of such printing is offset printing using the repulsive properties of two liquids: water and a hydrophobic ink.

Rotary printing generally requires at least one printing unit. By the term "printing group" will be understood throughout the present disclosure a set of cylinders and rollers described above allowing printing the paper strip in one color (for example black, magenta, cyan or yellow). Black and white printing requires only one print group printing in black. Color printing usually requires four print groups, each for a color (cyan, magenta, yellow, and black)

The ink used is thermosechant (in English and in the jargon of the printing "heatset"), that is to say that it dries heat unlike inks drying by oxidation. Thus, such inks require drying after being applied to the paper web.

Drying the paper web after rotary printing allows solvent evaporation of the ink used to fix the ink on the paper web.

The method may further include the auxiliary drying of the paper web directly after inkjet printing. Thus the ink used for inkjet printing is dried twice, first before offset printing and a second time after offset printing.

The method may further include guiding the paper web from the roll to rotary printing, i.e., to the first printing unit. The guiding of the paper web can be carried out using at least one set of rollers guiding the paper web. In this case, the inkjet printing is preferably performed against one of these rollers serving as a support for stabilizing the inkjet printing.

The method may further include cooling the paper web after drying following rotary printing.

The method may also include folding and / or cutting the paper web to form notebooks in the chosen format. The folding and / or cutting is done at the end, that is to say after drying and cooling if the latter is provided.

The transport of the paper web along the print line is generally carried out on a floating board.

The method may further comprise the siliconization of the paper before folding and / or cutting and after drying and optionally cooling.

A print line for printing common items and at least one custom item on a roll paper web is described hereinafter with reference to FIG. The print line 10 includes in the order of scrolling the paper web

8:

an inkjet printer 3 for printing at least one personalized item on the paper strip 8;

a rotary printer 4 for printing common elements on the paper strip 8; and

a main heat dryer 5 for drying inks deposited on the paper web 8 by the rotary printer 4.

The rotary printer 4 generally consists of at least one printing unit 41. Each printing unit 41 comprises rolls and rollers between which the paper web passes when it is printed. Each printing group 41 allows the printing of a color (black, magenta, cyan, yellow). For black-and-white printing, only one print group 41 for black printing is sufficient. For color printing, the print line 10 includes four (magenta, cyan, yellow, and black) four (adding black) printing groups 10, or more.

The print line 10 may comprise a unwinder 1 upstream of the ink jet printer and receiving a paper spool 9 for the unwinding of the paper strip 8.

The print line 10 may also include an auxiliary dryer 31 disposed between the ink jet printer 3 and the rotary printer 4 to dry the ink deposited by the inkjet printer 3 before the passage of the ink jet. paper web 8 in the rotary printer 4. The auxiliary dryer 31 can be integrated with the inkjet printer 3.

The printing line 10 may also comprise a guiding system 2 of the paper web disposed between the reel 9 and the rotary printer 4. In particular, the guiding system 2 may comprise sets of rollers guiding the web of paper. In this case, the inkjet printer 3 is preferably disposed on a stationary roller near the guide system 2. More particularly, the print heads of the inkjet printer 3 are then arranged facing the fixed roll near the guiding group so that the roll serves to support the paper web 8 at the time of its inkjet printing. This allows stabilization of the inkjet printing. The print line 10 may further comprise a cooler 6 disposed after the main heat dryer 5.

The printing line 10 may further comprise a folder-cutting machine 7 for folding and / or cutting the paper web 8. The folder-cutting machine 7 is arranged after the main heat dryer 5 and the cooler 6 if the latter is planned.

The printing line 10 may also include a group of siliconizer 71, preferably positioned between the cooler 6 and the folder-cutter 7.

Claims

claims

A method of printing a rolled paper web successively comprising:

- the inkjet printing of at least one custom item on the paper strip;

thermal offset printing of common elements on the paper web;

- Thermal drying of the paper web.

The printing method according to claim 1, further comprising drying the paper web directly after inkjet printing, and wherein the ink jet printing is performed using a aqueous ink.

The printing method according to claim 1 or claim 2, wherein the transport of the paper web is carried out on a floating edge.

4. Printing line (10) comprising successively in the running direction of a strip of paper:

an ink jet printer (3) for printing at least one custom item on a rolled paper web;

- a rotary printer (4) for thermally drying offset printing of common elements on the paper web; and

a main heat dryer (5) for drying the ink deposited on the paper strip.

The printing line (10) according to claim 4, further comprising an auxiliary dryer (31) disposed between the ink jet printer (3) and the rotary printer (4) for drying at least partially the ink deposited on the paper web by the ink jet printer (3) before the paper web passes through the rotary printer (4).

The printing line (10) of claim 4 or claim 5, further comprising a silicone group (71).

7. Printing line (10) according to one of claims 4 to 7, in the rotary printer (4) comprises at least one printing unit (41).