FR2792873A1 - PRINTING METHOD, ON IMPROVED ROTATING PRESS, IMPROVED ROTATING PRESS - Google Patents

Abstract

The present invention relates to a method for printing on a rotary press, a support delivered in the form of a strip (20) from a reel (10), said rotary press comprising a printing unit (2) using , to deposit the ink on said support, a flexible material (8). Said method typically comprises, intermittently, during the movement of said web (20), upstream of said printing unit (2), a deposit of fatty solvent over the entire width of said web (20) to be printed. The present invention also relates to a rotary press which is suitable for carrying out said process.

Description

The present invention relates to a printing process, on press

  rotary, improved, as well as an improved rotary press - modified, in the sense of

  the invention - suitable for implementing said method.

  According to the invention, an improvement is proposed to facilitate the operation of rotary printing presses, in particular the operation of rotary presses used to date in offset printing. Said improvement makes it possible to remedy problems, inevitably encountered, during the use, according to the prior art, of this type of printing equipment. Said improvement is all the more interesting as its field of application is vast: it can be implemented, on any type of rotary press, within the framework of any printing process using, to deposit the ink on the support to printing, a flexible material (of soft consistency) and in particular a rubberized material (such as a blanket, in offset) to print any type of support, conditioned in reels: paper, cardboard

Or other.

  On reading the following description of the invention, the man of the

  profession will understand that to date the scope of application of said invention is mainly that of offset but that in any event said invention is transposable, exploitable, beneficial in any printing context o, for

  deposit the ink on the support to be printed, we use a flexible material.

  A large part of the printing is carried out on rotary presses, which print the support to be printed, such as paper, packaged in reels. Before the end of a support reel during printing, a bonding of the unwinding strip, with the start of a new support reel, is generally carried out by an automatic adhesive device, known per se. A new coil is thus put into service, without stopping the press. Photoelectric cells detect the absence of a strip in the event of the support to be printed being broken and

  then cause the press to stop.

  On an offset press, the media to be printed passes between cylinders

  printing, at least one of which is covered with a rubber called a blanket.

  The ink is deposited on said support by said blanket.

  The main problems, inevitably encountered when using rotary presses (mainly offset, to date) are briefly mentioned below: 1) When pressurizing an offset press (when starting the printing), it relatively frequently happens that the support to be printed, in particular paper, remains stuck on the intervening blanket or on one of the intervening blankets (several blankets can intervene successively in a printing unit and / or two blankets intervene simultaneously for double-sided printing). This causes a rupture of the support strip and a winding of at least part of it around said blanket, mounted on a printing cylinder. Such a winding can have more or less serious consequences, which can range from a simple waste of time to the partial or total destruction of at least one printing cylinder and its accessories. 2) As the press is used, pollution of the printing cylinder (s) carrying a blanket is observed, pollution caused by the deposition, accumulation, of particles which detach from the print media, paper or cardboard. Said deposits cause a gradual deterioration of the print quality and are likely to cause, when they become very large (that they collapse at the edge of the width and interfere

  with the edge of the strip moving), the rupture of said support to be printed.

  3) During the bonding operations, for the commissioning of a new reel, without stopping the press, two other types of difficulties appear: 3a) the support coming from the end of the current reel is, at the level of the bonding joint, superimposed on that from the new coil. At the level of said joint, we are therefore in the presence of two thicknesses of support instead of one. When printing the strip, at this joint, the pressure is temporarily excessive; it is all the more excessive as the paper or cardboard involved is of heavier grammage. This excessive pressure can be

  sufficient to cause delamination of said paper or cardboard (support), that is

  ie a separation of the different layers of fibers constituting it. In such a case, a part of said destratified support is generally wound around one of the press cylinders, while the other can continue its course in the press. If this is the case, the belt not being broken, the press is not automatically stopped by the usual detection devices (rupture of said band) and the consequences of the incident on the mechanical parts of the press can be highly damaging; 3b) when the two successive bands of support are not in perfect alignment, one of the edges of the "new band" (from the new reel) is found in contact with parts of the printing cylinder loaded with particles, dirt, deposited on the edges of the width. We then observe a phenomenon of adhesion of said edge to the cylinder, adhesion phenomenon capable of causing a rupture of the strip and a winding of at least part of it around said cylinder. Such winding, as already indicated in point 1) above, can have more or less serious consequences, ranging from a simple waste of time to the total or partial destruction of at least

  minus a printing cylinder and its accessories.

  To said main problems, it has been proposed, according to the prior art, various solutions, specific, more or less satisfactory. Thus: 1) with reference to problem n 1, which could be described as bonding at start-up, it has been proposed, in the context of know-how, to spray, water, or even silicone water, on the blanket (s) in question. Such water only intervenes at start-up (the blanket (s) not yet being polluted); 2) with reference to problem 2, which could be described as pollution during printing, the printer currently has two technologies (to remove deposits): - either it stops the press and it performs a manual washing of the blanket (s) using an appropriate solvent and / or water, depending on the nature of the deposit; - Either it performs such washing, without stopping the press, thanks to an automatic blanket washing device that is found today on the market. There are in fact two types of such devices: those which rub the blanket with a damp textile substrate and those which rub said blanket with

  a brush or any other equivalent mechanical means.

  These two washing technologies are far from satisfactory.

  In the case of manual washing, there is an obligation to stop the press, which generates, at the same time: a significant waste of paper, during restarting; and a loss of production during the entire cleaning operation. Such a cleaning operation can be relatively long and must be carried out

  on all blanket cylinders in the printing unit.

  Furthermore, such a cleaning operation is not rewarding (it is hardly appreciated by operators, insofar as it is painful, dirty and tedious) and it generates pollution: cleaning substrates, such as rags or sponges, loaded with ink, solvents and various constituents of the support to be printed, on the one hand, and solvents and / or contaminated water, on the other hand, as appropriate,

thereafter, to deal with.

  In the case of the use of automatic washing machines, whatever their

  type, we also face many problems.

  Thus, with the scrubbers using a textile substrate, it is necessary to manage the consumption and the destruction of said substrate (generally a nonwoven). Said washers are also relatively bulky, can cause discomfort in the implementation of printing, require maintenance. Finally, the fact of exerting a friction on the blanket causes abrasion and therefore causes a

greater wear of it.

  Thus, with washers using a brush or any other equivalent mechanical means, it is necessary to manage the cleaning of said brush or of said other means. Said washers are also also relatively bulky, can also cause genes for the implementation of printing and also require maintenance (in particular with reference to the wear of the brush or equivalent means). Their intervention is also responsible for wear, for

abrasion, cleaned blankets.

  These solutions of the prior art, to problem n 2 identified and specified

  above, are therefore not fully satisfactory.

  3) 3a) with reference to problem 3a, which could be described as delamination, no real solution has been proposed. At best, the printer increases the wetting of the plate cylinder (upstream of the blanket cylinder), during bonding. Such wetting is not, however, a solution that suddenly solves the problem ...; 3b) with reference to problem 3b, which could be described as bonding on one of the edges, it has been recommended, in the context of know-how, the application of oil to the edges of the new coil. Such a local application has the effect of neutralizing the consequences of misalignment

  tapes. Its implementation, on an industrial scale, remains delicate.

  Confronted with these various technical problems, to which, to the knowledge of the inventor, there was, according to the prior art, only proposed solutions, distinct, specific, more or less satisfactory vis-à-vis, therefore, of only one of said problems (see above), said inventor currently offers a single original, global, complete and satisfactory solution vis-à-vis all

  said problems. This solution - original intervention of a fatty solvent -

  constitutes the basis of the invention currently claimed.

  Said invention is now described, successively, under its two aspects of method and device. The method of the invention is a method of printing, on a rotary press, a support produced in strip form from a reel. Said rotary press comprises a printing unit using, to deposit the ink on said support, a flexible material. This type of printing process is familiar to those skilled in the art. To date, this mainly involves offset printing which, to deposit the ink on the support, involves a blanket. In general, the improvement within the meaning of the invention is capable of being exploited in any context in which the ink is therefore deposited on the printing medium via a flexible material, and in particular a rubberized material (context limited to date

  to that of offset but undoubtedly called to expand in the future).

  In this printing context, on a rotary press, with the use of a flexible material for depositing the ink on the printing medium, according to the invention, it is typically proposed to deposit, intermittently, solvent bold over the entire width of the strip to be printed, when the said strip is scrolled; this deposition being carried out on said strip upstream of the printing unit. Said fatty solvent is deposited over the entire width of the moving strip, upstream of the printing unit, between said printing unit and the system for feeding the latter with said support strip to be printed. Said fatty solvent can be deposited on the front or / and on the back of said strip intended to be printed, generally on the front only or on the front / back. In fact, all

cases are possible.

  In the context of an advantageous variant, the printing is carried out on both sides and the fatty solvent is deposited on the two faces of the strip in movement. The improvement, object of the present invention, is based on the original concept of the use of the printing medium, itself, to convey a solvent for cleaning the cylinder (s) of the printing unit (more particularly printing cylinder (s), offset blanket cylinder (s)), to constitute itself a cleaning tool; said support behaving like a sponge capable of at least partially returning the solvent, with which it has been impregnated upstream, during its successive passages between the cylinders of the printing unit. With reference to problem no. 2 mentioned above, said printing medium advantageously replaces rags, sponges, textile substrates, brushes or equivalent mechanical means which should be brought into play according to the prior art, in a very quite unexpected. Indeed, the printing supports, paper in particular, being relatively fragile and scrolling materials, on the rotary presses, generally very taut, it was by no means acquired in advance that they could be used, successfully (without breakage) for transport (cleaning) liquid. However, it has proved quite possible

have this function performed.

  With reference to said problem No. 2, the deposition of fatty solvent, according to the invention, is carried out, discontinuously, at will, when it turns out

  necessary and of course, without stopping the machine.

  For an optimization of the expected cleaning, the fatty solvent is advantageously deposited over a length of the strip (in movement) at least equal to the circumference of the (first) printing cylinder called to contact said strip. Said cylinder can be single or the first of n cylinders (n, integer, greater than or equal to 2) which intervene one after the other, in the

printing group.

  The intervention of the fatty solvent, according to the invention, when the press is pressurized (when printing starts) avoids any break in the strip of printing support and therefore also makes it possible to avoid the problem n 1,

mentioned above.

  Similarly, those skilled in the art will have understood that said intervention of the fatty solvent, according to the invention, is beneficial, during the bonding operations, for the commissioning of a new coil, and this with reference to

  problems 3a and 3b, mentioned above.

  The deposit of fatty solvent according to the invention therefore proves to be the remedy

  unique, effective, to said problems 1, 2 and 3 mentioned above.

  It is, as indicated above, advantageously implemented: a) at start-up, to eliminate the risk of sticking to the blanket; b) at the same time or immediately after bonding, to avoid the risks of delamination and sticking. In the context of this variant of the method of the invention, the deposition of fatty solvent is carried out on the moving strip, at the end of a support coil to be printed, at the same time as or just after, the joining, by bonding , from said end of said reel and from the start of the next reel. Said deposit, upstream of the bonding joint is advantageously extended to at least cover said bonding joint. It is advantageously extended downstream of said bonding joint so that said fatty solvent is deposited on either side of said joint; c) during drawing to automatically carry out an intermediate blanket wash; d) at the end of the draw to automatically carry out cleaning

full of said blankets.

  A person skilled in the art will know how to optimize the intervention of the fatty solvent for the purposes of the invention, in particular in terms of quantity, in terms of length of impregnated strip (see above, the reference to the circumference of the cylinders called to contact said strip. ) and timing. Thus, it turns out to be particularly expedient to use said fatty solvent, during a change of coil by bonding (solution or problem n 3), in an amount such that it also ensures the

  cleaning the blanket (s) (solution to problem 2) ...

  We have spoken indifferently of printing cylinders and blanket cylinders insofar as, as already indicated, the context of the invention is

  mainly that of offset, while being in no way limited to it.

  In order to deposit fatty solvent, within the meaning of the invention (intermittently, on the moving strip, over the entire width (width) of said strip), various technologies can be used. Said fatty solvent can in particular be deposited by spraying or by direct application, using at least one brush or roller. Advantageously, the width of said deposit is

  adjustable, adaptable according to the width of the material to be printed.

  Advantageously, said deposit is implemented by spraying, at

  using at least one spray nozzle.

  The most suitable sequences of said deposit are chosen, taking particular account of the properties of the printing medium used. Thus, an automatic spraying trigger can be perfectly synchronized with the end of the gluing cycle, which guarantees a minimum waste of paper and

  perfect repeatability of the operation.

  The fatty solvent deposited is obviously capable of penetrating the

  print media pores, exert a cleaning action and non

  adhesion, while remaining compatible with all the packing materials of the different rollers and cylinders of a rotary press. It is advantageously a fatty solvent of the type of solvents marketed to date for the automatic washing of offsets blankets. Thus, do we recommend, in particular, the use, according to the process of the invention, of mixtures of organic solvents, marketed by the company ANCHOR under the trade names

"A 310" and "Turbo Autowash HHNP".

  Considering the above remarks and the examples appended to the

  present description, the skilled person will not fail to grasp all the advantages

  of the process of the invention. Some of these are listed below: the implementation of the process does not entail a high operating cost: the consumption of solvent is low and no consumable other than solvent and water is used. Water is mentioned here, to the extent that it is in fact in no way excluded from the scope of the invention, to involve, independently or not of the fatty solvent, water. Said water can advantageously take the same circuit (see below) as said fatty solvent. It can also be routed and delivered by other means. In any event, its intervention, from time to time, is particularly appropriate to get rid of mineral substances, kaolin type, which have detached from the support to be printed; - The implementation of said method causes neither pollution of the printing unit, nor pollution of the system supplying said group with printing medium, nor additional pollution, in general. In fact, the detergents, solvent, water and residues are eliminated by the strip. In the case of a dryer rotary press, the said solvents are completely evaporated and treated automatically by the post-combustion system of the installation. There is no risk of explosion, given the small amount of solvent involved. In the other cases, the small quantity of solvent impregnating the printing medium limits the quantity of residues entrained by the strip; which does not cause dirt on the folder organs. The density of said residues does not require any particular treatment, the recycling of the printing medium can be carried out in a conventional manner; the print quality remains constant throughout the print run; - production is greatly facilitated due to the elimination of the risk of sticking of the printing medium to the blanket, when the rotary press is pressurized - the printing medium lubricated by the solvent exerts, thanks to a slight sliding during the crushing of the blanket, a tiny friction but sufficient to clean it perfectly; - thanks to the principle stated above, the life of blankets is extended; - The energy cost of washing the blanket, according to the invention, by the printing medium, is much lower than that of manual or automatic washing of the prior art; - the process makes it possible to reduce the number of washing stations to be installed on the machine, which reduces the cost of the investment and the amount of

solvent used.

  We now propose to describe the invention in its device aspect The device of the invention, which is suitable for implementing the method described above, comprises a rotary press of the prior art with which it is associated means suitable for intermittent solvent deposition

  bold, on the entire width of the scrolling strip, for its printing.

  Said rotary press comprises, conventionally, a printing unit (including at least one plate cylinder and a blanket cylinder, associated, in offset) and, upstream thereof, a system for feeding it with a continuous web of the printing medium conditioned in reels. Said system comprises at least one unwinder, which ensures the unwinding of the reel and the transmission of the unwound tape to the printing unit. It also advantageously comprises, arranged downstream of said unwinder, a debtor. Such a debtor is a regulator of the tension of the printing medium delivered. He delivers

  said support at a constant rate.

  Typically, according to the invention, it is associated with said rotary press, means for depositing, intermittently (at will), a fatty solvent over the entire width of the strip to be scrolled. Said means are positioned downstream of the feed system of said rotary press (system comprising a decoiler and advantageously a decoiler and a debtor) and upstream of the group

printing of it.

  The printing medium, impregnated at this level with said fatty solvent, can develop the beneficial actions described above, while limiting the

maximum pollution generated.

  The means involved in the deposition of the solvent may in particular consist of at least one brush or roller. Advantageously, these are means which are suitable for spraying said fatty solvent. Thus, said means advantageously comprise at least one spray nozzle, arranged above and / or below the strip put to run and more advantageously still several spray nozzles on two booms, arranged respectively above and at below said strip. The said nozzle (s) must be suitable for spraying the fatty solvent over the entire width of the strip. It (s) is (are) connected (s) to a device for supplying said

  oily solvent and subject to control means.

  To avoid clogging of such spray nozzles, it is strongly recommended to spray compressed air at the end of each spraying of fatty solvent. Said nozzles may also be suitable for a

  water spray (see above).

  The spraying technique that can be used in the

  framework of the present invention is perfectly mastered by the skilled person.

  Drilled blocks can allow the distribution of different controlled fluids (solvent, water, compressed air). Solenoid valves adapted to the various fluids and to the frequencies used can make it possible to route said fluids to the spray nozzles on demand. With such a method, it is possible to pass through each nozzle, successively or simultaneously, from 1 to 3 different fluids. These solenoid valves can be managed by a PLC

  programmable or any other industrial computer-based system.

  It may thus be perfectly possible to program automatic sprays, a first, at the start of the printing process, then others synchronized at the end of the bonding cycles of two successive coils ... Furthermore, the device of the invention advantageously comprises, in a manner known per se, at its system for supplying the printing unit with the printing support strip (at its unwinder) an automatic device for securing by gluing two coils, used

  successively. Such devices are known per se.

  Considering the above remarks, the extreme simplicity of the means necessary for implementing the very advantageous method of the invention is achieved. It is proposed to list below, in no way limitative, advantages of the device of the invention, incorporating at least one spray nozzle: - it does not include a movable member and its maintenance is therefore very simple; - its adjustment is easy. There is no need to readjust its positioning; the problems of obturation of the nozzles can almost be reduced to nil by the quality of filtration of the intervening fluids and this also thanks to the self-cleaning cycle with compressed air, carried out at the end of each spraying; - The small footprint of said device allows its implementation, easy, on all types of machines; - it can possibly be installed and deposited with great ease, if this proves to be really necessary for possible interventions on the machine; - a priori, it does not interfere with the operator, during plate or blanket change operations; - its mounting on a press in operation is extremely easy and requires only a very short downtime; - its use is very simple and therefore requires only a very short teaching period; - its use brings an extremely important driving comfort; - such a device is versatile. It is likely to intervene in

contexts other than offset.

  It is understood that the list of advantages of the invention, also analyzed

  both in terms of process and device, is impressive.

  It is now proposed to describe said invention, in its two aspects, with reference to the single appended figure. On this, there is shown schematically a rotary press of the invention. This includes, from upstream to downstream, conventionally; a system 1 for supplying a printing group 2 with a strip 20 of printing medium to be printed; - said printing unit 2; - a drying oven 3;

- a cooler 4.

  Said system 1 comprises an unwinder 1a and a debtor 1b. Said unwinder contains an automatic securing device 6 by gluing the

  coils used successively 10,10 '.

  10 shows the spool of printing support in progress (during printing). Said coil 10 delivers the tape 20. The

  coil 10 ', new, will intervene when said coil 10 is exhausted.

  Said printing unit 2 comprises two plate cylinders 2a and 2a '

  and two blanket cylinders 2b and 2b '. The intervening blankets 8 have been represented symbolically (not on a scale). For the consideration of the said

figure man

  of the trade has already understood that the printing in question is a recto offset printing

  back. 5 shows a tape breakage detection cell 20.

  Typically, it intervenes, on either side of said strip 20, at the outlet of the debtor 1b, spray nozzles 30. They are capable

  to impregnate with fatty solvent the front and back of said strip 20, at will.

  The impregnation is advantageously implemented: - at the start of printing (with reference to problem n 1) - with each change of reel 10 (with reference to problems n 3a, 3bet2); and - at the end of printing (in reference to problem 2); It can also be implemented during printing, at any

  moment (with reference to problem 2).

  It is implemented without stopping the running of the strip 20. It causes a certain waste of support to be printed but avoids many problems which are reflected, them, by a greater waste of paper, by

  printing stops or even breakage.

  The presently claimed invention is illustrated by Examples 1 and 2 below, more specifically by Examples 1b and 2b, below, Examples 1a and 2a illustrating the prior art. Considering these comparative examples,

  a person skilled in the art will not fail to grasp the whole interest of the invention.

  Example 1a (Prior Art) A two-sided offset printing is carried out, in a conventional manner, with 9 reels of paper 10 km long each successively on a 16-page web press (comprising an unwinder with automatic gluing system of successive reels , a debtor and 4 color printing units), operating at a speed of 25,000 copies per hour, for a print run of 150,000 copies. The paper used is coated paper, with a grammage of 90 g / m2 and a width of 960 mm. The nth reel is automatically, at the unwinder, secured to the (n-l) th, by gluing. The following performances are recorded - Number of stops (s) generated by sticking to the blanket 1 during start-up (problem 1): - Number of stops (s) necessary for manual cleaning 2 of the blankets (problem # 2): - Time required for each manual cleaning of the 15 min blankets: - Time required for manual passage of the strip in 10 min the machine and restart (at each restart): - Waste generated during each bonding: 100 notebooks * - Waste generated during each start-up: 200 notebooks * - Time required for final blanket washing: 20 min Total time lost during this draw: 1 h ** Total run time: 7 h * The skilled person n '' is aware that each bonding (at each reel change) and each (re) start causes a waste of print media (here paper) and that a notebook of said print media has a length corresponding to a revolution of the cylinder print (here 600 nm) ** We can estimate at 3000 FF the cost of this loss of time (3000 FF

  corresponding to the hourly printing rate).

  Example 1b (Invention) Printing is carried out with the same material, under the same conditions (on the same rotary press, operating at the same speed, for the same printing, on the same printing medium), with however intervention according to the invention, each time the coil is changed, a fatty solvent. Said fatty solvent, the nature of which is specified below, is uniformly sprayed, under the conditions indicated below, on either side of the 960 mm in width of the strip of paper put on to pass. It is sprayed from 10 spray nozzles, distributed uniformly on two booms, arranged 54 mm above and below

  of the media scrolled. Said spray nozzles are of the H 1 / 8th type -

  VVII-001, sold by the company SPRAYING EMANI SYSTEM (USA).

  Characteristics of the spraying according to the invention: Solvent: mixture of organic solvents, sold under the name "A 310" by the company ANCHOR; Spraying of the solvent: the said solvent is sprayed for 0.8 s, under a pressure of 1.6 bar, which delivers 0.8 dl on each spraying. Given the speed of movement of the paper, said 0.8 dl are distributed over a length of 3.3 m of paper (this length corresponds to 5.5 revolutions of the blankets, it is symmetrically distributed on either side of the bonding joint). Self-cleaning of the spray nozzles: at the end of each spraying of solvent, compressed air is delivered through the nozzles for 2 times 1 s,

  with a pause of 0.5 s between each time.

  The following performances are recorded - Number of stops (s) generated by the blanket gluing 0 during start-up (problem n 1): - Number of stops (s) necessary for manual cleaning 0 of the blankets (problem n 2): - Time required for cleaning the blankets: 0 - Time required for the manual passage of the strip in 10 min the machine and at start-up (during the single start-up) - Waste generated during each bonding: 100 notebooks - Waste generated during each start-up: 200 notebooks - Time required for final washing: 0 Total time lost during this draw: 0 Total run time: 6 h By implementing the process of the invention, a economy, in production time of 1 hour, which corresponds to a substantial savings in production cost (see above). As a percentage, the gain of

  production is around 14.3%. The print quality remains constant.

  Finally, we save 600 notebooks, that is to say, we consume, in

  percentage, 0.375% less paper.

  Example 2a (Prior Art) The same type of offset printing is implemented (on a 16-page rotary press operating at the speed of 20,000 copies per hour, (slightly slower than in examples 1a and 1b), for a 150,000 copies), in

  using coated paper, a weight of 200 g / m2 and a width of 960 mm.

  20 coils 4.5 km long each are used successively of said paper, the

  going from one reel to the next by automatic gluing.

  The following performances are obtained: - Number of stops (s) generated by the bonding to the blanket 0 during start-up (problem n 1): - Number of stops (s) generated by the winding of the paper 1 around the blanket during gluing (problems no 3, due to the thickness of the paper): - Time required for the mechanical repair of the 1 hr machine (resynchronization of the cylinders): - Number of stops (s) required for manual cleaning of the blankets 3 (problem 2): - Time required for each manual cleaning of the 15 min blankets: - Time required for the manual passage of the strip in 10 min the machine and for restarting, each restarting - Waste generated during each collage: 100 notebooks Waste generated during each start-up: 200 notebooks - Time required for final washing: 20 min Total time lost during this draw: 2 h 45 min * Total run time: 10 h 15 min * We can estimate at 8250 FF the cost of this loss of time (3000 FF corresponda nt at the hourly printing rate) Example 2b (Invention) Printing is carried out with the same equipment, under the same conditions (on the same rotary press, operating at the same speed, (20,000 copies / hour), for the same print run, on the same print medium) as what was described above in Example 2a. However, each time the coil is changed, under the conditions described in Example 1b, the fatty solvent, as also defined in said Example 1b. Said solvent is sprayed on both sides for 0.7 s, under a pressure of 1.6 bar; which delivers 0.26 dl on each spray. Said 0.26 dl are distributed over a length of 2.33 m of paper. This length corresponds to 3.8 revolutions of the blankets, it is symmetrically distributed on either side of the bonding joint. A self-cleaning sequence of the spray nozzles is used, after each spraying of solvent, as described in Example 1b. The following performances are recorded Number of stops (s) generated by the sticking to the blanket 0 during start-up (problem n 1): - Number of stops (s) generated by the winding of paper 0 around the blanket during bonding (problems n 3): - Time required for mechanical repair of the 0 machine (re-synchronization): Number of stops necessary for cleaning the 0 blankets (problem n 2): - Time required for cleaning the blankets: 0 - Time required for the manual passage of the tape in 10 min the machine and restarting, during the single start - Waste generated during each bonding: 100 notebooks - Waste generated during of the single start-up: 200 notebooks - Time required for final washing: 0 Total time lost during this draw: 0 Total run time: 7 h 30 min By implementing the method of the invention, there is therefore a saving , in production time of 2 h 45 min, which corresponds to a substantial saving it in production cost (see above). As a percentage, the

  production gain is around 27%. The print quality remains constant.

  Finally, we save 800 notebooks, that is to say, we consume

  percentage, 0.5% less paper.

Claims (11)

  1. A method of printing on a rotary press, a support delivered in the form of a strip (20) from a reel (10), said rotary press comprising a printing group (2) using, to deposit the ink on said support, a flexible material (8), said method being characterized in that it comprises, intermittently, during the running of said strip (20), upstream of said printing unit (2), a deposit of fatty solvent over the entire width of said strip (20) to be printed.   2. Method according to claim 1, characterized in that said support is printed on both sides and in that said fatty solvent is deposited on both sides of the running tape.   3. Method according to one of claims 1 or 2, characterized in that it   this is an offset printing process.   4. Method according to any one of claims 1 or 3,   characterized in that said fatty solvent is deposited by spraying or by   application using at least one brush or roller.   5. Method according to any one of claims 1 to 4, characterized   in that said fatty solvent is of the type of solvents marketed for washing automatic blanket offsets.   6. Method according to any one of claims 1 to 5, characterized   in that said fatty solvent is deposited over a length at least equal to the circumference of the (first) printing cylinder (2b, 2b ') called to contact said band (20).   7. Method according to any one of claims 1 to 6, characterized   in that said deposition of fatty solvent is carried out on the moving strip (20), at the end of a roll of support to be printed, at the same time or just after, the joining, by gluing, of said end of said roll and from the start of the next reel. 8. Method according to claim 7, characterized in that said solvent   grease is deposited on either side of the bonding joint of the two successive coils.   9. Rotary press suitable for implementing a process   printing device according to any one of claims 1 to 8, comprising a   printing unit (2) and a system (1), unwinder (la) with or without debtor (lb), for supplying said printing unit (2) with a continuous strip (20) of the printing medium packaged in reels (10,10 '), characterized in that it further comprises, positioned downstream of said supply system (1) and upstream of said printing unit (2), means (30) for intermittently depositing a fatty solvent over the entire width of said strip (20), scrolled. 10. Rotary press according to claim 9, characterized in that said means (30) for intermittently depositing said fatty solvent,   comprise at least one spray nozzle, arranged above and / or   below said scrolled strip (20), advantageously several spray nozzles on two booms, arranged respectively above and below said scrolled strip; the said nozzle (s) being connected to a device   supply of said fatty solvent and subject (s) to control means.   11. Rotary press according to one of claims 9 or 10, characterized   in that said supply system comprises an automatic device for   joining (6) by gluing, of the two coils (10,10 '), used successively.