DE10157270B4 - Method for operating a rotary printing machine - Google Patents

Abstract

Method for operating a rotary printing press for waterless offset printing, wherein a temperature (T) of a cooperating with an ink jacket surface of a forme cylinder (03) running first cylinder (03) tempered and controlled by a tempering device (18, 19), and wherein the printing ink is transferred from the forme cylinder (03) to a printing material (09) via a second cylinder (07) designed as a transfer cylinder (07), characterized in that to reduce the plucking between the printing ink and the paper having a coating weight of the highest 20 g / m ² running substrate (09) only the forme cylinder (03) is tempered, and that for production speeds (V) in the range of 9 to 14 m / s a temperature (T) of 32 ° C to 37 ° C in the near-surface region of the forme cylinder (03) is adjusted.

Description

The The invention relates to a method for operating a rotary printing press according to the generic term of claim 1.

By JP 62-191 152 a control is known, wherein a cooling of a Roller temperature depending on is switched on or off from the operating state of the printing press. While the production is cooling dependent on from the surface temperature a form cylinder regulated.

The EP 06 52 104 A1 discloses a printing unit for waterless offset printing with various options for controlling the temperature of the surface of cylinders. So z. B. during the preparation for the printing operation preheating, and during printing a constant maintenance in a certain temperature range, a pressure plate on the forme cylinder z. B. at a constant temperature of 28 to 30 ° C, possible.

Also in the literature, z. In Walenski, the web offset printing 1995, is in connection with the waterless offset printing a temperature of the Plate and transfer cylinder as a condition for called the printing of high-quality printing results, with the temperature the pressure plate to 25 to 28 ° C. to be held constant.

In the EP 0 886 578 B1 discloses a printing unit, wherein in a partially enclosed space an inking unit and the ink-carrying cylinder are arranged. In order to avoid cloning on one side and drying out of the printing ink on the other side, the partially enclosed space is kept at a predeterminable temperature and a certain level of atmospheric humidity or concentration of chemical substrates. For example, the entire room is maintained at a set point of 33.8 ° C, a humidity of 75% and / or a concentration of chemicals of 300 ppm.

The DE 197 36 339 A1 discloses a tempering of rollers and / or cylinders of a printing unit in order to make an adjustment of the ink feed rate and / or printing material quality.

Of the Invention is based on the object, a method for operation a rotary printing press for to create the waterless offset printing, which in an effective way ensure high quality printing at high production speeds.

The The object is achieved by the Characteristics of claim 1 solved.

The particular advantages of the invention are that a high print quality and a trouble-free Operation, both at low and at high production speeds is achieved.

Especially the method is suitable for use in waterless offset printing, because in this printing process especially the building up of printing ink and pollution on the color-leading Components is a problem. U. a. can in the absence of dampening solution an increased, and for If necessary, the printing process or the printing inks used too high a temperature occur in the printing unit. Due to the lack of fountain solution, soiling, Paper dust and fibers u. U. not effectively out of the process become.

Building up ink and dirt on one side and toning or clogging the printing plate 04 By "wrong" temperatures on the other hand is effectively reduced, and ideally prevented.

Advantageous it is also that with the method or the device an ideal Adapted to different printing inks and / or substrates can be. By the scheme, a troublesome plucking between color-transmitting Cylinder and printing material effectively prevented or reduced.

In an advantageous embodiment the form cylinder of the printing unit is tempered, without the additional Generation of a gas flow on its surface, but from the form cylinder ago such. B. an introduced into the form cylinder temperature control, Evaporating agent etc .. This accelerated evaporation of color ingredients and premature dehydration can thereby be prevented. Also to a setting of a special room climate and possibly to be provided exhaust air purification are significantly reduced To make demands.

Furthermore is by the process a significant saving of energy over conventional Procedures, wherein, for example, the cylinders each on a single, fixed low temperature are possible.

An embodiment of the invention is illustrated in the drawing and will nä in the following described here.

It demonstrate:

1 a schematic representation of a printing unit for waterless offset printing;

2 a schematic representation of relationships between temperature, tack and production speed;

3 an embodiment of a control scheme;

4 an exemplary setpoint specification a) as a table, b) as a step function c) as a continuous curve.

A printing press, in particular a rotary printing press, has a printing unit 01 on which at least one inking unit 02 , one a printing form 04 carrying cylinder 03 , z. B. a form cylinder 03 , as well as an impression cylinder 06 having ( 1 ). The printing unit 01 is as a printing unit 01 designed for offset printing and points between the forme cylinder 03 and the impression cylinder 06 another cylinder 07 , z. B. a transfer cylinder 07 with a lift 08 on its outer surface. The transfer cylinder 07 forms with the impression cylinder 06 in a print-on position on a substrate 09 , z. B. a printing material web 09 , a bruise 11 , The impression cylinder 06 can another transfer cylinder 06 a non-designated further printing unit, or a non-printing ink leading impression cylinder 06 , z. As a steel or a satellite cylinder, be.

The printing form 04 may be sleeve-shaped or as one (or more) pressure plate 04 be executed, which is fastened or suspended with their ends in at least one narrow, not exceeding a width in the circumferential direction of 3 mm, channel (indicated in FIG 1 ). Likewise, the elevator 08 on the transfer cylinder 07 sleeve-shaped or as (at least one) blanket 08 be executed, which is also attached and / or tensioned in at least one channel. Is the blanket 08 designed as a multi-layered metal blanket, the channel is also designed with the above-mentioned maximum width.

The inking unit 02 has a paint supply 12 , z. As a paint tray with fountain roller or lifter, or a chamber doctor blade with ink supply, and at least one of the form cylinder 03 in a pressure-on position engagable roller 13 , z. B. an applicator roll 13 on. The ink is in the example of the paint supply 12 about as an anilox roller 14 executed roller 14 , the roller 13 , the form cylinder 03 and the transfer cylinder 07 on the substrate 09 transported. It can also be a second, with the anilox roller 14 and the form cylinder 03 co-acting applicator, not shown 13 be arranged.

The printing unit 01 is designed as a so-called "printing unit for waterless offset printing" (dry offset "), ie that in addition to the supply of ink no further supply of a dampening solution for the formation of" non-printing "areas is required printing form 04 omitted, which otherwise in the so-called "wet offset" the non-printing parts on the printing form 04 prevents it from accepting printing ink. In waterless offset printing, this is achieved through the use of special inks and the special design of the surface on the printing form 04 reached. So z. As a silicone layer in waterless offset printing take over the role of assignable with dampening hydrophilic range of wet offset, and the printing plate 04 prevent the color pickup.

Generally, the non-printing areas and the printing areas of the printing form become 04 achieved by the formation of areas of different surface tensions when interacting with the ink.

Around sound-free, d. H. without the non-printing areas as well Accept ink and possibly even clog, print, it requires an ink that in its speed (measured as tack value) is set so that due to the surface tension difference between printing and non-printing parts on the plate a flawless Separation can take place. Since the non-printing sites preferably is formed as a silicone layer, for this purpose, a printing ink with one opposite the wet offset much higher tackiness needed.

The tackiness For example, according to "The Web Offset Printing", Walenski 1995, the resistance with which the ink of the film split in one Nip or during transfer the ink in the print zone between cylinder and substrate and counteracts. It usually becomes in roller systems, z. In a "tack-o-scope" or a "tackmeter".

Since the tack of the ink changes with temperature, in practice, the operation of the printing press becomes the cylinder 03 ; 07 or the inking unit 02 cooled and maintained at a constant temperature to avoid toning for changing operating conditions during printing.

The tack of the ink affects ne However, the separation of printing and non-printing areas also the strength of a plucking in the interaction of a color-guiding cylinder 03 ; 07 with the substrate 09 , Especially if the substrate 09 As uncoated, low-density newsprint paper with very good absorbency, ie open-pored and with a very short break-up time, is executed, the risk of loosening of fibers or dust caused by picking increases. This danger is but z. B. also used in web offset printing lightly coated or lightweight, coated paper grades with a coating weight of z. B. 5 - 20 g / m ² , in particular 5 - 10 g / m ² or even less before. Overall, the temperature is particularly suitable for uncoated or coated papers with a coating weight of less than 20 g / m ² . For coated papers, the method may u. U. be advantageous if it is found that the stroke is "pulled off" by increasing speed from the paper (at least partially).

To a plucking or building up on the blanket and the printing plate 04 To keep as low as possible, trying to produce the ink for the intended use and the expected operating conditions as possible at the lower limit of the speed and use.

With respect to the toning of the non-printing areas on the printing form 04 In addition to the tack of the printing ink, the relative speed during the detachment process, ie when the printing ink is split or detached, plays a decisive role.

The printing ink generates at higher production speed V (corresponds to the surface speed of the printing cylinder ( 03 ); 07 or the conveying speed of the printing substrate 09 , measured z. In m / s) in the nip both between roll 13 and the printing form 04 of the forme cylinder 03 as well as between the printing form 04 of the forme cylinder 03 and the elevator 08 on the transfer cylinder 07 greater tear-off forces. The lower the relative speed, z. As the intended production speed V is, the higher the speed of the ink to choose to prevent cloning at lower production speeds V. Otherwise, the wrong choice for poor print quality or during startup leads to increased paper waste and high maintenance.

Increases the dynamic speed with increasing production speed V, so there is usually a stronger plucking on the substrate 09 and increased buildup of soiling and ink on the printing form 04 , This has complications and an increased maintenance frequency, z. B. frequent washing of the surfaces, when the tack was designed for a lower or middle range of the production speed V.

This problem, which is currently not solvable even by a special choice of printing ink, has been recognized in its context and has been solved by the method and the control device described below. With the method and the device in each area for the production speed V plucking and the associated introduction of fibers and dust in the printing unit 01 avoided or reduced. At the same time, for each production speed V, toning of the printing form takes place 04 forged and achieved a high print quality.

One or more of the color-guiding components, such. B. in an advantageous embodiment of the form cylinder 03 as a color-guiding component 03 , or / and the printing ink itself, is tempered as a function of the production rate V. The temperature T is not kept constant for all production _speeds V in a specific temperature range, as otherwise customary in waterless offset printing, but has different setpoint values T _SO1 for different production _speeds . The temperature T is regulated as a function of the production speed V such that the tack of the printing ink at any desired production speed V is within a predefinable window of tolerable tack values. For a higher production _speed V is an increased setpoint T _SOll for the temperature T of the corresponding component 03 or the ink selected.

An example for the dependencies of the relations between the temperature T and the tack (tack value) as well as between the production speed V and the tack (tack value) is in 2 shown schematically. Regardless of the size and the scale graduation for the tack values, this decreases with increasing temperature T and increases with increasing production speed V. The two curves for the temperature T and the production speed V each represent only a single curve of an entire family of curves. The curve of the temperature T represents the dependence of the tack value at a constant production speed V, while conversely, the curve for the production speed V represents a curve for a constant temperature T.

A suitable for printing tack (tack value) is in the "printing area" from Tackwerten, ie in a window _Δ Z. The boundaries of the window _Δ Z are formed id R. soft, ie at sub bzw.- exceeded deteriorates Quality not abrupt but gradually. However, the tack values for the respective printing ink determined, for example, by paint manufacturers are dependent on the measuring device used and the method, so that the dependency and the window _{ΔZ are} off 2 for different methods and measuring devices must be converted into each other accordingly.

The example in 2 shown values show the dependencies only schematically by means of a single representative for the respective crowd curve. However, the values for a suitable window _ΔZ are based, e.g. For example, to test results on an "Inkomat" from the company Prüfbau They are to be transmitted in a different manner to be determined according to the above dimensions.

Also, the tearing behavior described above, in addition to the tack value, may also depend on the radius of curvature of the cooperating surfaces, so that when the cylinder is considerably larger than the present case 03 ; 07 , ie with a circumference of about 800 to 1,200 mm, even the desired window _Δ Z for the tack value can easily move.

The trouble-free printing in waterless offset printing window _Δ Z for the tack is z. B. between 6 and 8.5, in particular between 7 and 7.8. When reducing the tack, increased toning occurs in the "tone range", increased plucking and increased buildup on the cylinders when enlarged in a "pluck-build" area 03 ; 07 on.

The method is based on the control principle that for the intended, imminent, or current production _speed V as a _reference variable, a specific desired value T _SOll or maximum value T _MAX for the temperature T of the component 03 or the ink is assigned as the output size.

This can, as in 3 exemplified, carried out by means of a timing chain, wherein z. B. a control device 16 the production speed V is supplied as a reference variable in the control device 16 based on a stored context 17 between the production _speed V and the setpoint T _SOll for the temperature T, the required setpoint value T _SOll or a maximum value T _MAX not to be exceeded is determined and as the _reference variable of a control device 18 is supplied. This control device 18 keeps the temperature T of the component 03 or the ink as a controlled variable over a controlled system 19 at the target value T _SOll constant, or brings them to the target value T _SOll or ensures that the temperature T does not exceed the maximum value T _MAX . As temperature T of a component 03 is preferably the temperature T in the near-surface region of the component 03 in particular to understand the temperature T of a cooperating with the ink jacket surface.

The component 03 or the ink can by means of a conventional control device 18 For example, a cooling and / or heating unit, a Temperiermittelkreislauf, via variation of a Temperiermittelstromes, u. U. also by blowing appropriately tempered or sized in its flow gas / air flow or other common methods as a controlled system 19 be brought to the appropriate temperature T as a controlled variable. Because the printing unit 01 In waterless offset printing, among other things because of the lack of cooling effect of the dampening solution usually heated more than desired, is in this case as a controlled system 19 only a cooling device 19 to provide for the temperature, which the component 03 or the ink on the production _speed V corresponding setpoint T _SOll leads or holds on this. In this case, each production _speed V can also be _assigned the maximum value T _MAX for the temperature T instead of a setpoint value T _SOll , which is determined by means of the control device 18 monitored and adhered to.

The information about the desired and / or the current production speed V can, for example, manually by input via a with the control device 16 operatively connected input unit 21 take place and possibly in the further course of the values of a machine control 22 be matched. It is advantageous, instead of a manual input, to enter the data for the desired and / or current production speed V from a program sequence of the machine control on which the production is based 22 refer to.

The control device 16 and the control device 18 can be summarized structurally and in the machine control 22 or the structural design of the controlled system 19 be integrated.

In a simplified embodiment, instead of the control device 16 also the possibility of specifying the desired value T _SOll or the maximum value T _MAX as a _reference variable for the control device 18 be made in another way, for example by means of manual dialing. In this case as well, the selection of the setpoint T _SOll or of the maximum value T _MAX, for example, made by the printer, is an above-mentioned relationship 17 , possibly in the form of a table.

4 shows an example and schematically a context 17 as stated in a rule scheme according to 3 in or for the control device 16 as table a), as a section-wise defined step function b) or as a continuous, monotonically increasing function c) can be stored in a memory unit, not shown, or a computer. For printing inks of different "basic consistency", for example of different manufacturers or different composition, different contexts can arise from each other 17 be deposited. This also applies to different colors of the printing ink.

Depending on the component to be tempered, z. B. the form cylinder 03 , the transfer cylinder 07 , the color supply 12 , the roller 13 , the roller 14 as a color-guiding component 03 ; 07 ; 12 ; 13 ; 14 , or the ink itself, such a table may have different values.

In an advantageous embodiment, by means of the method and the device of the forme cylinder 03 of the printing unit 01 tempered, since this effectively meets both the requirement of sound-free printing on one side, and the reduction or, on the other hand, the avoidance of picking on the other side with minimal effort. In contrast to the tempering of the inking unit 02 finds the temperature of the forme cylinder 03 both near the printing form 04 , as well as in sufficient proximity to the substrate 09 co-acting pressure point 11 ,

The form cylinder 03 becomes in the case of a non-steady connection 18 ( 4 , b)), for example, in a lower region of the production speed V, z. B. between 1 to 4 m / s, to a temperature T of about 20 to 25 ° C, in particular from 21 to 23 ° C tempered. For greater production _speeds V out of the temperature T is assigned a higher setpoint T _SOll or maximum value T _MAX , which for example, for production _speeds V of 4 to 6.5 m / s between 26 and 31 ° C, in particular at 27 to 29 ° C. For production speeds V, which more than z. B. 6.5 m / s, for example, setpoint values T _SOll and maximum values T _MAX for the temperature T of the forme cylinder 03 assigned, which are greater than 30 ° C. If, for example, the production _speed V is 6.5 to 11 m / s, a setpoint T _SOll or maximum value T _MAX in the range of, for example, 30 to 37 ° C is assigned. In finer subdivision, production speeds V of 6.5 to 9 m / s z. B. a range of 30 to 35 ° C and for production _speeds V of 9 to 14 m / s a target value T _SOll or maximum value T _MAX of about 32 to 37 ° C, z. B. 34 to 36 ° C, or assigned to greater than or equal to 35 ° C. For even higher production speeds V, even higher values for the temperature T can be assigned. It can the present range of 1 to 14 m / s in less, z. B. in only two or three stages, or else in more stages, each with a temperature T to be assigned. It may also be advantageous to use the relationship as a continuous function as exemplified in FIG 4c) to deposit.

If other conditions exist, eg. As printing inks with significantly different properties, a substrate 09 which has a different surface texture from uncoated newsprint paper and / or a completely different picking behavior, the values of the relationship may deviate significantly from the stated values. Common to the solution, however, is still the regulation of the temperature T of the forme cylinder 03 depending on the production _speed V, such that it has a higher target values T _SOll or maximum values T _MAX in a range of higher production _speeds V than for a range of lower production _speeds V. The plucking is thus _{prevented by} means of the method and the device color leading cylinder 03 ; 07 and the substrate 09 diminished and ideally almost prevented.

For high production speeds V, z. B. from 6.5 m / s, it is of particular advantage that the temperature T in contrast to previous solutions Values of 30 ° C and set larger becomes. Only then can the plucking and the associated fouling for high Production speeds V are effectively prevented.

If a rotary printing machine with high production speeds V, z. B. with 6.5 m / s and more, it is also possible in an embodiment, not shown, to dispense with the aforementioned regulation of the temperature T as a function of the production rate V, and in principle a temperature of the component 03 , in particular of the forme cylinder 03 , or a maximum value T _MAX contrary to previous practice to a temperature T of greater than 30 ° C, z. B. to provide a temperature T of 32 to 37 ° C.

With the temperature of the forme cylinder 03 , in particular the temperature of the printing form 04 on its side facing away from the printing ink, to above 30 ° C in the high speed of the production speed V Tonnies printing is possible in comparison to the previous practice, without the printing forme 04 is added with printing ink without printing areas leading too little or too much color, and without fibers and / or dust from the printing substrate 09 over the transfer cylinder 07 in the printing unit 01 is introduced. An expense which a separate temperature of the forme cylinder 03 (low temperature) and in addition the transfer cylinder 07 (Higher temperature) with it, is advantageously by the present choice of the temperature T for the forme cylinder 03 avoided. In addition, a high cost of housings, air conditioning and exhaust air cleaning is avoidable, as he, for example, in convective cooling of the inked, outwardly directed side of the printing form 04 is required. The form cylinder 03 In an advantageous embodiment, therefore, can be flowed through by a Temperiermittelstrom, which is controllable either in its mass flow or in an advantageous manner over its temperature.

For during the Startup possibly lower production speeds V is at Adherence to certain time intervals and the right choice of Time for the pre-run or the connection of the temperature, with increasing Production speed V and associated heating never an outside of the desired or given tack value.

01

printing unit

02

inking

03

Cylinder, Form cylinder, component

04

Printing form, printing plate

05

06

Impression cylinder, transfer cylinder

07

Cylinder, transfer cylinder, component

08

Elevator, blanket

09

substrate, printing material

10

11

bruise

12

Ink pumping, component

13

Roller, Application roller, component

14

Roller, Anilox roller, component

15

16

control device

17

context

18

control device

19

Controlled system, cooling device

20

21

input unit

22

machine control

T

temperature

T _target

setpoint for the temperature

T _MAX

maximum value for the temperature

V

production speed

.DELTA.Z

window the tack / pressure range

Claims (2)

Method for operating a rotary printing machine for waterless offset printing, wherein a temperature (T) of an envelope surface of a cylinder acting as an impression cylinder ( 03 ) executed first cylinder ( 03 ) tempered and by means of a tempering ( 18 . 19 ), and wherein the printing ink from the forme cylinder ( 03 ) via a transfer cylinder ( 07 ) executed second cylinder ( 07 ) on a substrate ( 09 ), characterized in that in order to reduce the plucking between the printing ink and the printing substrate (as a paper having a coating weight of at most 20 g / m ²⁾ ( 09 ) only the forme cylinder ( 03 ) and that for production speeds (V) in the range of 9 to 14 m / s a temperature (T) of 32 ° C to 37 ° C in the near-surface region of the forme cylinder ( 03 ) is set. A method according to claim 1, characterized in that a flow or the connection of the tempering ( 18 . 19 ) and a sequence for increasing the production speed (V) before and / or within the scope of a starting operation of the rotary printing press in such a way that a range (.DELTA.Z) of predetermined tack values for the tack of the printing ink is not left.