WO2007045404A1

WO2007045404A1 - Method for printing textile printing materials

Info

Publication number: WO2007045404A1
Application number: PCT/EP2006/009911
Authority: WO
Inventors: Rüdiger Oehler
Original assignee: Oehler Ruediger
Priority date: 2005-10-21
Filing date: 2006-10-13
Publication date: 2007-04-26
Also published as: EP1940622A1; DE502006004541D1; EP1940622B1; ATE439236T1; DE102005050915A1

Abstract

The invention relates to a method for printing textile printing materials, especially silk, by sheet-fed offset printing, whereby a sheet of printing material and a sheet of an electrically non-insulating material are printed alternately so that the electrostatic charge occurring during printing of the sheets of printing material between the rubber-covered cylinder and the counter-pressure cylinder of a sheet-fed offset printing machine is eliminated by the sheets of electrically non-insulating material. The invention also relates to a device for printing textile printing materials, comprising means for alternately printing sheets of printing material and sheets of electrically non-insulating material by sheet-fed offset printing, and to the use of such a device for printing textile printing materials.

Description

Process for printing textile substrates

The invention relates to a method for printing textile substrates according to the preamble of claim 1, an apparatus for printing textüer substrates, and a use of such a device for printing textile substrates, in particular of silk.

Textile substrates are typically produced as continuous material on rolls and continuously printed on one or both sides during the unwinding of the roll and the simultaneous rolling on another roll by means of rotating pressure rollers (gravure printing, continuous printing, digital printing, screen printing). Gravure:

Unsuitable due to the color consistency (and their solvents TuIoI and XyIoI) and uneconomical due to enormous pre-cost).

Continuous printing:

Unsuitable, application only in label area (smallest formats).

Digital printing:

Unsuitable, due to the color consistency, no counter pressure possible.

Screen printing:

Unsuitable due to color consistency, poor registration, no counter pressure possible.

A disadvantage of such methods is that in these exact multi-color printing with high registration accuracy is not possible because in multi-color printing with several consecutive rotating pressure rollers through which the substrate passes, a high registration accuracy can not be ensured. For the same reasons, a mirrored backside or counter pressure, which coincides congruently with the front page print, is not possible. As a result, it is not possible with the known methods, for example, posters, flags, pictures and the like made of textile substrate, which viewed in the backlight have a high congruence of the front and back side print, as well as a multi-color printing with high registration accuracy. A higher register accuracy can typically be achieved in sheetfed offset printing, in which, instead of a continuous material, individually cut sheets are printed.

Offset printing is a planographic printing process in which printing and non-printing elements of the printing form lie in one plane. The printing areas of the printing form are wetted by paint, the non-printing ones are not wetted. During printing, a printing plate, or in the case of multi-color printing, a part of the printed image reproducing printing plate is moistened and colored. The ink is transferred from a blanket to the substrate. This transfer process from the plate cylinder on the blanket cylinder on the printing cylinder with substrate is necessary so that no dampening solution reaches the substrate. The offset printing is thus an indirect printing method because it is not printed directly from the printing form to the substrate.

Offset printing has not been used for textile substrates, as due to the use of a blanket for transferring the printing inks and due to the typically electrically insulating properties of the textile substrates used the substrate electrostatically charges, resulting in adhesion of the substrate on the blanket or back pressure. In addition, sheet-fed offset printing in conjunction with textile printing materials causes the problem that the printed sheets warp and / or stick together during drying.

The invention is therefore based on the object to develop an improved method for printing textile substrates, with a high registration accuracy is achieved and even smaller runs can be produced economically. The object is achieved in a method of the type mentioned fact that alternately a sheet substrate and preferably in its dimensions to the dimensions of the sheet of the printing material corresponding sheet is printed from an electrically non-insulating material, so that during the printing of the sheet From electrostatic charge occurring between the blanket cylinder and impression cylinder of a sheet-fed offset printing machine is eliminated by the sheet of electrically non-insulating material. As a result, wrinkling of the sheet of substrate is prevented by electrostatic charging. Another advantage that results from the alternate printing of sheet of substrate and sheet of electrically non-insulating material is that the so-called delivery of the printed sheet can be set to a delivery pile much more accurate to the format of the sheet. Without the sheets of electrically non-insulating material, an electrostatic charge would build up between the sheets of printing material even when the sheet is laid out onto the output stack if the sheets of printing material strike one another in the delivery. In extreme cases, it may happen that the sheet of substrate despite open gripper are not designed and run back into the sheetfed offset press, which can lead to significant damage to the machine. Due to the alternating printing and thus also laying sheets of substrate and sheet of electrically non-insulating material, this is effectively prevented.

Due to the alternating printing of the textile substrate and the electrically non-insulating material, the entire print run can be driven stable and without wrinkling and wave formation of the textile substrate. In this case, first sheet are prepared, which stacked in alternation both sheets of the substrate, as well as in their dimensions preferably include the dimensions of the sheet of the printing material corresponding arc of an electrically non-insulating material. Both the substrate and the electrical non-insulating material are initially wound, for example, as endless material on rolls. The rolls are handled simultaneously and the unwound strips of material are brought together. The printed sheets are then first cut from the merged endless material by means of a roller cross cutter and then cut to the exact dimensions required for printing on all sides and stacked alternately, so that each sheet is a sheet of the electrically non-insulating material and vice versa. The sheets of substrate and of electrically non-insulating material are preferably alternately stacked before all-round cutting, so that cutting the sheet of substrate and made of electrically non-insulating material takes place simultaneously. The stacks are then stored until printing at a constant humidity of preferably at least 50%, whereby static charges of the printed sheets are prevented. The sheets are then printed alternately, so that one sheet of printing material and one sheet of the electrically non-insulating material is printed one after the other.

The inventive method has over the prior art has the advantage that the static charges of the textile substrate are eliminated by the alternate printing of the textile substrate and the electrically non-insulating material, whereby the textile substrate stability in sheet travel and wrinkling is prevented. In addition, the alternating supply of textile substrate and electrically non-insulating material in the entire manufacturing process, in particular between blanket cylinder and impression cylinder in the sheetfed offset press, eliminates electrostatic charges, which improves sheet travel and handling of the textile substrate. If the sheets alternately stacked stored before and after printing, may be due to lying between the sheets of substrate sheet of electrically non-insulating Material form or receive no electrostatic charges, which, for example, improves the necessary before printing separation of the sheet and also the delivery of the printed sheet from the sheetfed offset press.

According to an advantageous embodiment of the method according to the invention it is provided that the sheets of substrate and of an electrically non-insulating material are alternately stacked before printing and fed from a common feed pile from a sheetfed offset printing machine. The sheets of electrically non-insulating material which are alternately stacked between the sheets of printing material prior to printing in the feed stack prevent electrostatic charging of the sheet fed to one another on the sheet-fed offset printing press, the so-called following sheet. Without the laid in the feed stack between the sheet substrate made of electrically non-insulating material run at most 50 sheets of substrate trouble-free from feed pile, as charged by the friction of the already retracted sheet remaining piling so that the subsequent sheet only as so-called oblique sheet or Follow as a so-called double bow or do not even break the pile. The alternating stacking of the sheets of printing material and electrically non-insulating material according to the invention on a common feed stack effectively solves this problem.

According to a further advantageous embodiment of the method according to the invention it is provided that the sheets are alternately stacked after printing on a common delivery stack, so that follows a printed sheet of electrically non-insulating material on the delivery stack of each printed sheet substrate. By displaying the printed sheets on a common delivery stack, the delivery can be adjusted much more accurately to the format of the sheets. Without the between the bow Printed sheet designed sheet of electrically non-insulating material would build up an electrostatic charge between the sheets of substrate even when the delivery when the sheets of substrate at the display strip on each other. In extreme cases, it may happen that the sheet of substrate despite open gripper are not designed and run back into the sheetfed offset press, which can lead to significant damage to the machine. By alternating printing and thus outputting sheets of substrate and sheet of electrically non-insulating material, this is effectively prevented.

An advantageous embodiment of the method according to the invention provides that the printed sheets of the printing material and the printed sheets of the electrically non-insulating material are stacked alternately at a constant humidity of preferably at least 50% dried. The alternating stacking prevents the sheets of the printing material from sticking together during drying, since this prevents ink from being deposited on the back of the sheets of printing material, so that blocking or sticking of the sheets to each other is avoided. In addition, in a multi-color printing, the subsequent printing operations are simplified, since then again from the top starting a sheet can be printed after another, so again in turn an arc of the substrate and a sheet of electrically non-insulating material are printed. Due to the special drying of the colors at constant, relatively high humidity, dents and distortion of the textile substrate are prevented. The constant humidity of 50% also contributes to a uniform drying possible without edge distortion of the bow. It prevents too fast drying of the sheet edges, which would otherwise lead to a plate-shaped distortion of the sheet, and thus helps to maintain the registration accuracy. Furthermore, a prevents static loading of the sheets, which otherwise leads to considerable difficulties in sheet travel with a high reject rate.

Another advantageous embodiment of the method according to the invention provides that the drying time is at least 24 h. During the drying time, the sheets are left alone and not transported, moved or processed. This is followed by each printing in a multi-color printing a corresponding drying time. Due to the long drying time at constant, high humidity, edge distortion of the printed sheets is prevented, whereby a high registration accuracy is achieved with multi-color printing and with an additional, mirror-inverted backside printing a high level of congruence. In addition, at a relatively high humidity of at least 50%, the inks dry slowly, improving color reproduction. In addition, the brilliance of the printing material recurs due to the slow drying, which improves the impression of quality, especially when printing on silk. The relatively high humidity also effectively prevents electrostatic charging of the sheet from the substrate, which improves the processability, for example, in a multi-color printing or subsequent backside printing, as well as the separation of the sheets of the printing material and the sheet of electrically non-insulating material after completion of the print.

A particularly advantageous embodiment of the method according to the invention provides that the sheets of the printing material and the sheets of electrically non-insulating material are exactly cut before printing by means of a four-sided angle section. Due to the all-round, exact cutting, especially in connection with the long drying at constant humidity, a high register accuracy is achieved in multi-color printing, and a high level of coverage with the front side pressure in mirror-reversed back pressure, which is of particular importance for posters, flags and similar printed textiles, which can be viewed in backlight, for example.

Preferably, the sheets are cut alternately stacked. In order to obtain a register-accurate front and / or backside printing, the format difference between the individual sheets may not exceed 1 to 2 mm. This is achieved by cutting the sheets of stock together with the sheets of electrically non-insulating material, such as paper, in relatively small stacks with a low stack height. The cutting of the sheet of substrate with inserted sheet of electrically non-insulating material is preferably carried out on a plan cutter. Without the lying between the sheet of substrate sheet of electrically non-insulating material no such accurate orientation of the substrate is possible, creating format differences of up to 5 mm. By already inserted in the cutting between the sheets of substrate sheets of electrically non-insulating material of the substrate is stabilized and can not be so low when cutting in the stack, or can not be pressed together as much during the pre-pressing and section as otherwise this occurs when cutting a stack exclusively of textile substrate.

An additional advantageous embodiment of the method according to the invention provides that the sheets of the printing material and the sheets of electrically non-insulating material are stored before printing at a constant humidity of at least 50%. Due to the constant air humidity already during the storage of the printing sheet prepared for printing, it is ensured that the printed sheets do not warp. The level of humidity has been chosen so that an electrostatic charge of the printing material is effectively prevented. This will improve the quality of the print and the handling improved with the press sheets during oppression, as well as reduces the rejects. The humidity during storage of the unprinted printed sheets and the subsequent drying on the printing is preferably identical, so that the printed sheets are exposed to a constant humidity throughout the process, whereby a marginal distortion of the printed sheets is reduced and the dimensional accuracy and the registration accuracy is increased.

A further advantageous embodiment of the method according to the invention provides that the sheets of the printing material and the sheets of the electrically non-insulating material after printing the front and the subsequent drying on its back can be printed.

An advantageous embodiment of the method according to the invention provides that the sheets of printing material and the sheets of electrically non-insulating material are manually turned in front of the backside printing. Preferably, the sheets of substrate and the sheets of electrically non-insulating material are alternately stacked turned. By the example, stacked on the output stack between the sheet of substrate sheet of electrically non-insulating material, the stability of the arc is reinforced when turning. Without the sheets of electrically non-insulating material stacked between the sheets of substrate, a precisely aligned stack could not be achieved. If the sheets, for example, after printing the front side alternately spent consecutively on a common output stack, it can be lifted directly to turn a stack from the output stack and turned.

Another advantageous embodiment of the method according to the invention provides that the back pressure is mirror-inverted relative to the front side print, so that a congruent print image is generated in the backlight. According to an advantageous embodiment of the method according to the invention, the sheets are stacked after the one- or two-sided printing alternately stacked to a final format exactly. For the so-called final trimming of the finished printed sheets, the same specifications apply as for trimming before printing. Without the sheets of electrically non-insulating material alternately stacked between the sheets of printing material, the printed sheets of printing material can not be cut so precisely. By the final trimming of the alternately stacked sheets, a format accuracy of 1 to 1, 5 mm can be achieved, so that the printed sheet can then be applied, for example, to a prefabricated Belpe exactly fit.

According to an advantageous embodiment of the method according to the invention, the printing substrate comprises silk, in particular acetate silk or a polyester with back acrylate coating.

According to another advantageous embodiment of the method according to the invention, the electrically non-insulating material comprises paper. The paper preferably has a basis weight of 90 g / m ² offset paper, 1.1 vol. On.

According to a further advantageous embodiment of the method according to the invention, the wiping water used are free of alcohol additives. By dispensing with alcohol additives, the surface of the textile substrate is not attacked. This achieves a more brilliant color reproduction.

An advantageous embodiment of the method according to the invention provides that the humidity during drying and / or cutting is constantly 50%. An additional advantageous embodiment of the method according to the invention provides that the sheet of electrically non-insulating material as Vorlaufmateria! is used for setting up the machine for sheet travel and setting up the printing plates.

Another particularly advantageous embodiment of the method according to the invention provides that the color and tone values are adapted to match the color reproduction on the printing substrate, the corrected color and tone values preferably being below the standard values of a linearly running gradation curve. The peculiarity of the color and tonal corrections lies in the fact that due to the textile structure of the printing material metrologically no constant result can be achieved and the values can not be corrected by densitometric measurements.

The invention further relates to a device for printing textile substrates, which comprises means for alternately printing sheets of substrate and sheets of electrically non-insulating material in sheet-fed offset printing. The device according to the invention allows the implementation of the method according to the invention described above and thus allows to take advantage of the method.

According to an advantageous embodiment of the device according to the invention, this means for storing the prepared for printing, preferably alternately stacked sheets and / or means for drying the preferably alternately stacked printed sheet at a constant humidity of preferably at least 50%.

According to another advantageous embodiment of the device according to the invention, this means for all-round, exact cutting of the preferably alternately stacked sheets before printing. In this case, the all-round cropping is carried out in a multi-color printing only before the first printing process, and at a back page printing only before printing the front.

According to an additional advantageous embodiment of the device according to the invention, this means for all-round, exact cutting of preferably alternately stacked sheets after printing.

The invention also includes a use of the above-described apparatus for printing textile substrates.

The invention will now be explained in more detail with reference to exemplary embodiments. Show it:

Fig. 1 is a schematic representation of the sequence of a method according to the invention, as well

2 is a schematic representation of the cutting of sheets of printing material according to the prior art,

Fig. 3 is a gradation curve for dyeing and

Levels correction when printing on textile substrates.

A method shown schematically in FIG. 1 proceeds as follows:

In a first method step 1, the data for the print template are processed. In method step 2, the printed sheets are prepared by, for example, an unwrapped on a roll endless fabric supplied as well as a likewise delivered as endless, electrically non-insulating material, such as paper unrolled and merged, and cut by means of, for example, a roll cross cutter to sheet. Since the blank by means of the roller cross cutter, especially for a multi-color printing with high registration accuracy and a mirror-inverted backside printing with high congruence is not accurate enough, the sheets are in pairs, in small stacks, where alternately a sheet substrate is on a sheet of electrically non-insulating material, all sides for example, cut by means of a plan cutter.

In method step 3, the sheets of the printing material as well as the sheets of the electrically non-insulating material are stored alternately stacked at a constant atmospheric humidity of 50%.

In method step 4, the printing device is set up, whereby initially preferably not the expensive printing material but for example sheets of the electrically non-insulating material or of another suitable auxiliary material are used for setting up.

In process steps 5 and 6, the printed sheets are printed, wherein from the feed stack alternately a sheet substrate (step 5) and a sheet of the electrically non-insulating material (step 6) is printed.

This is done until all printed sheets of a stack are printed (step 7). The sheets are laid out alternately stacked on a common delivery stack.

If a stack is completely printed, it is dried in process step 8 at a constant atmospheric humidity of 50% for at least 24 h, whereby during drying, in turn, the sheets of printing material are stored on the sheet of the electrically non-insulating material.

If a further color has to be applied, for example in the case of a multicolor print (step 9), the process steps 5 and 6 are again carried out with a different color after drying.

If, in addition, the reverse side is to be printed mirror-inverted congruently with the front side (step 10), the sheets lying alternately on a common stack are first turned in pairs in step 11, in small stacks, and then again in a further process step 4 with the printing device set up the one-sided printed sheet. Subsequently, the method steps 5, 6, 7, 8 and optionally the method step 9 are repeated until the desired printed image is printed on the front and back.

The method ends in method step 12.

The production of posters consisting of double-sided printed silk sheets will be described in detail below.

The printing material is preferably made of acetate silk or polyester fabric with back acrylate coating. The offset printing inks used for textile printing are specially tailored to the material used. moreover is dispensed with the use of alcohol-containing additives in fountain solution, as this attacks the surface of the substrate, whereby the color impression is falsified. In addition, a dusting powder is used.

First of all, a check of the digital print templates for their usability takes place in prepress. Necessary requirements are, for example, a resolution of at least 350 dpi and that these are open files. The term open files means that an adjustment of the data color values with respect to a gradation correction can be made. For the adaptation to the abovementioned printing materials, a color and tone value correction is carried out in accordance with a gradation curve shown in FIG. Depending on the printed image, additional manual retouching is necessary, for example, a special adaptation of skin tones and technical raster gradients.

The substrate is typically produced and delivered in rolls of about 400-500 m / roll as raw material. To prepare the substrate additionally paper is required, which is also produced and delivered as roll goods to 3500 m / roll. The substrate and the paper are combined in a roll cross cutter and cut to the desired length section, so that in the result stacked on a pallet in alternation sheets of substrate and paper lie. The offset paper preferably has a basis weight of 90 g / m ² , with a volume of 1.1, which thus corresponds to the volume of the textile substrates and thus leads to a uniform printing of the printing press.

The cut sheets are then cut on a planer with a four-sided angle cut again exactly to the exact print format. In this case, both the sheet of the substrate, as well as the sheet of paper as well as the installation of the printing press required flow sheet tailored. The four-sided angle cut ensures both high registration accuracy in multi-color printing as well as high registration accuracy of the front and back with mirror-inverted backside printing. Preferably, the sheets are cut alternately stacked. In order to obtain a register-accurate front and / or backside printing, the format difference between the individual sheets may not exceed 1 to 2 mm. This is achieved by cutting the sheets of stock together with the sheets of paper in relatively small stacks with a low stack height.

Without lying between the sheet of substrate sheet of electrically non-insulating material no such accurate orientation of the substrate is possible because the applied on a support table 1 to a saddle 2 sheet of substrate 5 otherwise during cutting, as shown in Fig. 2, by a pressing beam 3 and a knife 4 are significantly compressed, creating format differences of up to 5 mm. By the present invention already when cutting between the sheets of substrate inserted sheet of electrically non-insulating material of the substrate is stabilized and can not be so low when cutting in the stack, or can not be pressed together so much during the pre-pressing and the cut, as otherwise occurs when cutting a stack exclusively of substrate.

The printed sheets prepared for printing are then stored at a humidity of at least 50%. With lower air humidity, there are considerable static charges and warping of the printed sheets, as a result of which it is no longer possible to achieve optimum print quality with regard to scrap and register accuracy. The preparation of the printing press and the auxiliaries is largely as in the usual offset printing, with a complete color change is performed on the specially produced textile dyes. To apply the dusting powder, a powder apparatus is used which is preferably adjusted to grain size 30 and a powder quantity of 99% (stage 2 Grafixapparat).

The printing machine is set up initially by means of 90 g paper sheets, with which the registration accuracy is set. Subsequently, about 100 sheets of the substrate are printed for fine adjustment.

Now, the desired edition is printed, whereby in each case a sheet of the printing material and a sheet of paper are printed alternately. It should be noted that twice the number of copies required is printed because the paper sheets are printed as well. By printing the substrates and the paper sheet in alternation, the static charge of the substrate is eliminated, given the substrate stability in sheet travel and prevents wrinkling of the substrate.

The printed sheets (substrate and paper) are stacked for drying after printing. The stack height is preferably depending on the area coverage at most 80 cm, otherwise lock the lower arc. The printed sheets are stacked for at least 24 h at a relative humidity of 50% constant dried without further processing. Due to the constant humidity of 50% and the resting of the material during drying, a low material distortion and in particular in a subsequent backside or counterpressure a high registration accuracy is achieved. Due to the driers in the ink, the stack temperature increases, the sheets are suitable only after dropping the stack temperature to ambient temperature for further processing. The drying time is strongly dependent on Print motif or from the area defined by the print motif area coverage. With high area coverage, the drying time can be up to 48 hours. The drying of the colors is mainly by oxidative drying and is specially adapted to the printing of silk, for example. Too fast drying causes the overlay to become blocked or the paper sheets to stick to the silk material. In addition, if too fast drying the paint would only dry superficially and lead to significant problems in further processing (scrubbing and lubrication). The constant humidity of 50% is very important here, as during rapid climatic changes a significant delay of the material occurs and also strong electrical charges occur that make a second printing process impossible and also lead to considerable difficulties in further processing.

The stack temperature in the stack center can be monitored and controlled automatically, for example manually, or by means of a temperature sensor or the like. It is also important to ensure that no moisture of the ink is more noticeable.

For a subsequent tailor-made backside printing, also known as counterpressure, the sheets are turned manually. Pile turner or the like can not be used due to the lability of the signatures.

The press is re-set up for counter-pressure according to the procedure described above. It is important to ensure that the drawing brand must be changed. The subsequent counterpressure is in turn carried out as described above, wherein alternately an arc of the printing substrate and a sheet of paper is printed. For further processing, the printed sheets are fanned out and inserted in a vibrating table by hand. By means of a cutting machine adjusted to the desired final format, final cuts are made in small layers of maximum 5 cm height each. Depending on the strips to be used, on which the cut-to-size printing material is to be mounted as a poster, a bleed allowance must be set. For example, this is 10 mm for angle strips and 12 mm for round strips.

The printed sheets are set after the final trimming and the printing stock and paper sheets are separated. The sheets of paper used as interleaf sheets are no longer used and are rejected.

In a subsequent quality control, the color reproduction is visually inspected, since the printing material used no metrological color control is possible.

After the quality control, the individual posters printed on both sides can be packed according to the existing orders. Preferably, the individual posters are rolled individually or in larger quantities together with intermediate paper sheets, which serve the scuff protection, and welded watertight in bags. This is particularly important because water droplets affect the surface of the substrates used and there is a ding. The bags are then placed in corrugated boxes to prevent bruising and damage to the substrate and loading during transport.

The invention is particularly applicable industrially in the field of textile printing.

Claims

claims

1. A process for printing textile substrates, in particular of silk, in sheetfed offset printing, characterized in that alternately a sheet of substrate and a sheet of an electrically non-insulating material is printed, so that during the printing of the sheet of substrate between blanket cylinder and impression cylinder a sheetfed offset printing machine occurring electrostatic charge is eliminated by the sheets of electrically non-insulating material

2. The method according to claim 1, characterized in that the sheets of substrate and of an electrically non-insulating material are alternately stacked before printing.

3. The method according to claim 1 or 2, characterized in that the sheets are alternately stacked after printing on a common delivery stack.

4. The method according to any one of the preceding claims, characterized in that the printed sheets of the printing material and the printed sheets of the electrically non-insulating material are stacked alternately at a constant humidity of preferably at least 50% dried.

5. The method according to claim 4, characterized in that the drying time is at least 24 h.

6. The method according to any one of the preceding claims, characterized in that the sheets of the printing material and the sheets of the electrically non-insulating material are accurately cut before printing by means of a four-sided angle section.

7. The method according to claim 6, characterized in that the sheets are cut alternately stacked.

8. The method according to any one of the preceding claims, characterized in that the sheets of the printing material and the sheets are stored from the electrically non-insulating material before printing at a constant humidity of at least 50%.

9. The method according to any one of the preceding claims, characterized in that the sheets of the printing material and the sheets are printed from the electrically non-insulating material after printing the front side and the subsequent drying on its back.

10. The method according to claim 9, characterized that the sheets of the printing material and the sheets of electrically non-insulating material are manually turned before the backside printing.

11. The method according to claim 10, characterized in that the sheets of substrate and the sheets of electrically non-insulating material are alternately stacked turned.

12. The method according to any one of claims 9 to 11, characterized in that the back pressure against the front side printing is mirror-inverted, so that in the backlight a congruent print image is generated.

13. The method according to any one of the preceding claims, characterized in that after the one- or two-sided printing, the sheets are stacked alternately stacked to a final format exactly.

14. The method according to any one of the preceding claims, characterized in that the printing material comprises silk, in particular acetate silk or polyester with back acrylate coating.

15. The method according to any one of the preceding claims, characterized in that the electrically non-insulating material comprises paper.

16. The method according to claim 15, characterized that the offset paper has a basis weight of 90 g / m ² with a 1.1 volume.

17. The method according to any one of the preceding claims, characterized in that the mop water used are free of alcohol additives.

18. The method according to any one of the preceding claims, characterized in that the humidity during drying and / or cutting is constant 50%.

19. The method according to any one of the preceding claims, characterized in that the sheet of electrically non-insulating material is used as a feedstock for the setup process of the machine for sheet travel and the setting up of the printing plates.

20. The method according to any one of the preceding claims, characterized in that for adjusting the color reproduction of the substrate an adjustment of the color and tone values, wherein the corrected color and tone values are preferably below the normal values of a linear gradation curve.

21. An apparatus for printing textile substrates, comprising means for alternately printing sheets of substrate and sheets of electrically non-insulating material in sheet-fed offset printing.

22. The apparatus of claim 21, comprising means for storing the prepared for printing, preferably alternately stacked sheet at a constant humidity of preferably at least 50% and / or means for drying the preferably alternately stacked printed sheet at a constant humidity of preferably at least 50% ,

23. Device according to one of claims 21 or 22, comprising means for all-round, exact cutting of the preferably alternately stacked sheets before printing.

24. Device according to one of claims 21, 22 or 23, comprising means for all-round, exact cutting of the preferably alternately stacked sheet after printing.

25. Use of a device according to one of claims 21 to 24, for printing textile substrates.