DE102006061341A1 - Method for controlling the transport of ink in an inking system of a printing machine comprises adjusting the temperature of an ink duct roller using a tempering system in the inking system and controlling the temperature - Google Patents

Abstract

Method for controlling the transport of ink in an inking system (6) of a printing machine comprises adjusting the temperature of an ink duct roller (8) using a tempering system in the inking system to a lower value than the temperature of an inking system roller (11) and controlling the temperatures of the ink duct roller and the inking system roller depending on the temperature values. An independent claim is also included for an inking system used in the printing machine. Preferred Features: The temperature difference for tempering the ink duct rollers and the inking system rollers is selected depending on the ink consumption of a pressure mold.

Description

The The invention relates to a method according to the preamble of the claim 1 and a device according to claim 10.

In Offset printing machines often become highly viscous Processed inks. The rheological properties of this Printing inks are referred to as thixotropic, that is the viscosity of the printing inks is minimized, among other things by movement. To the printing ink in the for a high quality print required evenly thin layers of paint of only a few microns thick, therefore, become common relatively expensive inking units with a variety of inking rollers between which the ink is transferred through a cleavage process becomes. The printing ink usually becomes by means of a ink fountain roller from a paint box of dosing influenced taken and the next Inking roller provided in a first color layer. This is usually a squeegee roller, the color layer intermittently from the ink fountain roller decreases, or a film roller, the color layer continuously from the ink fountain roller, and into one of the inking rollers formed color roller train, at the end of one or more Ink rollers for coloring a pressure plate are arranged. In sheetfed offset printing are mostly four inking rollers are used and in web offset printing often only two inking rollers used. Accordingly, the inking rollers divided into ink roller trains.

basics The task of an inking unit is to provide color reliefs that are after a zonal different color output of ink to the printing plate the inking rollers inevitably arise, over a new coloring from the inking rollers as possible Completely to equalize before the next Contact of the inking rollers to the printing plate is done.

There the for a high quality printing suitable color transport in one Multi-roll inking unit depending on the sujet is and a printing unit at the same time for processing a variety of Sujets must be suitable, it is particularly in color works of Offset printing units desirable, To be able to influence the color distribution in the inking unit.

It It has been shown that the color splitting at the outlet of an inking unit nip is dependent on the temperature of the inking rollers involved. A arranged in a color roller train cooled inking roller leads in comparison to the uncooled Condition a thicker layer of paint.

Devices of this kind are for example from the DE 4335097 A1 , of the DE 9316932 U1 and the DE 4202544 A1 known. With the so-called tempering the viscosity of the transported ink is influenced. In this case, tempering devices have become known in almost all places of printing units and inking units.

The tempering can be made possible by means of the inking rollers through-flowing heat-bearing media from the inside. Frequently, temperature sensors are used to detect the surface temperature of inking rollers or cylinders in order to regulate the temperature of the tempering medium accordingly. The location within an inking unit is described by the ink fountain roller on friction rollers to inking rollers. In particular, however, the function of tempering is described for cooling and stabilizing the color transport. In the DE 4335097 A1 is described as a further effect, the reduction of pollution in a printing unit and the associated inking unit. It is not known how the color transport in an inking unit can be influenced by the devices described.

task The invention is a method of operation and an associated inking unit to create in which avoided the disadvantages of the prior art be controlled and the color transport in an inking unit as needed can be.

The Task is procedurally with the features of the patent claim 1 and according to the device with the features of the claim 10 solved.

The According to the procedure of the invention before, that in a tempering of an offset printing unit set the temperature of the ink fountain roller to a lower value is the temperature of the following heatable rollers in the ink roller train.

Preferably this behavior is used in printing sujets with relatively low color guide.

By an increased Temperature difference between ink fountain roller and inking unit, wherein the ink fountain roller has a lower temperature than that Following inking rollers, a higher color density when applying paint on the substrate with otherwise identical operating parameters such as speed, opening of Farbdosierelementen, Hebertakt etc. reached.

This behavior brings straight in the poster or display printing with high demands on the color transfer and the color density in Erschei image on the substrate offers great advantages. Here, a very fast coloring constant is still achieved in the printing process.

The required temperature control can over the Control of individual zones of the distributor roller done. This is a system over a manifold and control valves built.

It exists the possibility over the Farbwerktemperierung within certain limits a color density control to integrate.

in this connection showed in corresponding experiments that by a temperature control according to the invention the ink fountain roller to a constant 27 ° C and a temperature setting the distributor rollers at 13 ° C above the temperature of the ink fountain roller an increase in the Value of the color density of up to 0.30 density values, d. H. around. 30% is achievable.

in the The following will be described with reference to drawings in an embodiment the invention closer explained.

In this demonstrate

1 an overview of an offset printing unit,

2 a schematic representation of a device in a first embodiment of the invention and

3 a schematic representation of a device in a second embodiment of the invention.

In 1 a printing unit for sheetfed offset printing is shown in detail. The printing unit contains a form cylinder 1 , a transfer cylinder 2 and a the substrate transport in sheet travel direction 3 Serving impression cylinder 4 , The transfer cylinder 2 are in a known manner a dampening unit 5 and an inking unit 6 assigned. The production of a printed image on a printed sheet takes place in a printing gap between the transfer cylinder 2 and the impression cylinder 4 , The dampening unit 5 has in addition to a dampening solution and dampening solution rollers and a fountain solution application roller.

The inking unit 6 has a color box 7 , a ductor or ink fountain roller 8th and a squeegee roller 9 , In the color box 7 are still in association with the ink fountain roller 8th Dosing systems not shown here provided. For this purpose, so-called color slides or colorimeters are usually used, which are opposite the ink fountain roller 8th produce a metering gap that can be changed according to the color requirement. The dosing gap is zonal controllable and can be automatically adjusted in conjunction with a so-called color control system on the basis of color density measurements on the sheet.

The lifting roller 9 is provided with a viscoelastic reference and with the help of a non-illustrated drive oscillating alternately against the ink fountain roller 8th and a first transfer roller 10 is hired. The first transfer roller 10 In practice, it is usually designed as a so-called distributor roller. Furthermore, the inking unit has 6 over several further distributor rollers 11 , The distributor rollers 11 are rotatably and adjustably driven axially oscillating. Finally, there are four inking rollers 12 provided by means of which printing ink in the required amount to one on the forme cylinder 1 tensioned pressure plate is applied after this from the dampening unit 5 was moistened.

To create a stationary color transport, the inking unit 6 be filled. Only after all rollers, depending on their arrangement in the compactor and their surface condition including their surface temperature lead a certain color layer on their active surfaces, a stationary color transport can be set. The color transport is considered to be stationary if local nonuniformities of the ink layer thickness exceed the layer thickness differences resulting from the process start.

From the upper distributor roller 11 go two roller trains, each with two more distributor rollers 11 and transfer rollers the ink flow to four inking rollers 12 to lead. The division into roller strands results in a special color flow distribution. Inks of this type can often also be reversed in such a way that a standard configuration, a front-loading configuration or a symmetrical configuration with respect to the color flow distribution can be used during printing.

The inking rollers 12 apply the ink to the printing plate, from which the printed image on the transfer cylinder 2 on the substrate on the impression cylinder 4 is applied.

It is now planned, the distributor rollers 11 the roll compact individually and independently or together with the whole roll train to temper.

The temperature of the inking unit 6 can in a known and here only schematically illustrated manner by flowing through the corresponding whale zen with a temperature control, z. B. according to heated or cooled heat transfer medium, such as. As water, take place.

For this purpose, a Temperiermittelkreislauf with Temperieranschlüssen TF for the ink fountain roller and T1 to T4 for the distributor rollers 11 intended. The Temperiermittelkreislauf is provided with a cooling or heating device for the temperature control. The temperature control is fed by means of feed pumps via appropriately guided lines and the temperature control TF or T1 to T4 the respective rollers axially and removed again.

The actual temperature control for the ink layer on the ink fountain roller can either directly above the detection of properties of the ink or indirectly over the Capture of properties of the temperature control carried out.

To This purpose can be achieved with the help of on the surfaces of the tempered inking rollers directed sensors, the temperature of the inking rollers or the Ink detected and subsequently controlled or regulated.

on the other hand can the control or regulation of the temperature also with the help of control valves under detection of the temperature of the temperature control and the adjustment of this temperature via heating or cooling and a suitable backmixing while the circulation or the control of the flow rates done.

It there is also the possibility by means of an inline density detection and, if necessary, control on the printed sheet on the basis of the measured values obtained indirectly on the temperature control act.

In 2 and 3 schematics are shown, according to which the system can work.

In 2 is a compilation of cutouts according to the already described inking unit 6 shown schematically. For four printing units D1 to D4 are symbols for marking the ink fountain rollers 8th and of friction rollers 11 specified. The ink fountain rollers 8th are joined together by means of a temperature control TF. The distributor rollers 11 In turn, the temperature control system with individual terminals T3 / T4 or with a sum terminal T1 ... T4 are connected.

In this way, the temperature of the ink fountain rollers 8th completely independent of the temperature of the distributor rollers 11 be set.

When Controlled variable can the return temperature be used of the temperature control.

In 3 is a section of the already described inking unit 6 shown schematically for a single printing unit. Again there are symbols to indicate a ink fountain roller 8th and of friction rollers 11 specified. The ink fountain roller 8th is connected by means of a Temperiermittelanschlusses TF via a control valve RF to a temperature control T. A first upper friction roller 11 In turn, by means of a Temperiermittelanschlusses T1 via a further control valve R1 to the temperature control T is connected. connected to individual terminals T3 / T4 or to a summing terminal T1 ... T4. Two further distributor rollers 11 are connected by Temperiermittelanschlüssen T3 / T4 via a further control valve R3 to the temperature control T.

Also in this arrangement, the temperature of the ink fountain roller 8th completely independent of the temperature of the distributor rollers 11 be set. As a controlled variable, the return temperature of the temperature control can be used. The temperature of the ink fountain roller 8th can be done by means of the control valve RF to a flow rate control.

The inking unit 6 is operated as follows:
About the squeegee roller 9 gets a color flow from the ink fountain roller 8th to the first distributor roller 11 transported. The ink fountain roller 8th and the distributor roller 11 are tempered. They are flowed through independently of each other by means of temperature control, with appropriate devices to feed this and circulate. The Temperiermedienströme or Temperiermedientemperaturen in the ink fountain roller 8th and the or the distributor rollers 11 are independently controllable with respect to both the amount and the temperature of the tempering medium. Therefore, at the ink fountain roller 8th a different temperature level than at the or the distributor rollers 1 ,

The color flow in the inking unit 6 depending on the temperature levels at the ink fountain roller 8th or the distributor rollers 11 then as follows:
When tempering the ink fountain roller 8th to a lower temperature level compared to the temperature level of the distributor roller or distributor rollers 11 the flow of color from the ink fountain roller 8th over the lifter roller 9 to the distributor roller 11 strengthened. As a result, by appropriate control of the temperature control in an undersupplied compactor, z. B. in subjects that require only small amounts of ink in certain colors, are supplied at the same setting the color metering relatively more ink. This will always be a sufficiently large amount of ink on the inking rollers 12 provided to saturate the printing areas of the printing plate with ink.

To improve a control possibility of a sensor for detecting color layer thicknesses can be provided. Here, the ink layer thickness z. B. on the first distributor roller 11 detected. Depending on the ink requirement on the printing form then the ink layer thickness can there by the control mechanisms described by means of the temperature of the ink fountain roller 8th and the distributor roller or the distributor rollers 11 be changed relative to each other. Process-dependent changes can then be easily readjusted.

By reversing and increasing the temperature difference between the ink fountain roller according to the invention 8th and the rollers of the inking unit 6 a color flow improvement and thus an increase in the color density in ink application to the substrate are achieved with otherwise the same operating parameters. Thus, a strong quality improvement is achieved especially when printing large-scale, color-intensive images with high demands on the color transfer or the color density in the appearance on the substrate. This continues to be a very fast coloring constant in the printing process.

The required temperature control can be controlled by individual zones of the temperature-controlled inking rollers 11 respectively.

It finally exists even the possibility about the inking unit according to the invention in limited scope a novel method of color density control to integrate.

For this will be inline during of the printing process and within the printing press or offline outside the printing process on devices outside the printing press the Printed sheet measured in terms of its color density printed per color. Based on the measured values, it is determined if too much ink, sufficient Printing ink or too little ink applied to the sheet has been.

In the event that too little ink was applied, the control device of the tempering system can be influenced so that the temperature level at the ink fountain roller 8th is lowered by a defined amount. This will make more ink in the inking unit 6 promoted and produced a saturation of the ink supply on the sheet.

In the event that too much ink was applied, the control of the tempering system can be influenced so that the temperature level at the ink fountain roller 8th is raised by a defined amount. This will reduce the amount of ink in the inking unit 6 promoted and a reduction in the ink supply to the sheet to the necessary degree.

The required temperature differences between the ink fountain roller 8th and the temperature-controlled inking rollers 11 can be stored as curves in the prepress, inking system or machine control.

The parameters are the area coverage of the image to be printed and the ink consumption determined thereby, the type of printing ink, the general temperature level in the inking unit 6 , the density level in the respective print image, the temperature level of the ink in the ink fountain 7 , a limit temperature for the operation of ink fountain 7 and dosing systems, the speed of the printing press and possibly other printing parameters in question.

The characteristic curves can be used in the presetting or the production control of the press via the control console for use in the respective inking unit 6 be retrieved. Likewise, the characteristics can be stored in the temperature control and by means of the machine control in connection with the respective color setting on each inking unit 6 be retrieved.

• 1. Vorwählen einer Temperierkennlinie entsprechend der vorliegenden Vorstufendaten
• 2. Regeln der Temperierung während eines Druckauftrages
• 3. Beobachten des Färbungsverhaltens am Druckbogen ggf. durch Dichtemessung oder Messung von Farbschichtdicken auf Farbwerkswalzen
• 4. Anpassen bzw. optimieren der Temperiereinstellungen in kleinen Schritten
• 5. Temperatur der Farbkastenwalze soll möglichst konstant gehalten werden
• 6. Abspeichern der durch die veränderten Einstellungen neu gewonnenen Kennlinie
• 7. Abspeichern der Kennlinie in Verbindung mit den Auftragsparametern des abgearbeiteten Druckauftrages
• 8. Aufrufen der gespeicherten Kennlinie bei Wiederholung des Auftrages oder bei Ausführung eines ähnlichen oder gleich parametrierten Auftrages

To adapt the method and the device to the mechanical conditions, a work cycle of the following type can be selected:

• 1. Preselect a tempering characteristic according to the present pre-stage data
• 2. Control the temperature during a print job
• 3. Observing the dyeing behavior on the printing sheet, if necessary by density measurement or measurement of ink layer thicknesses on inking rollers
• 4. Adjust or optimize the temperature settings in small steps
• 5. Temperature of the ink fountain roller should be kept as constant as possible
• 6. Save the new characteristic obtained by the changed settings
• 7. Save the characteristic curve in conjunction with the job parameters of the processed print job
• 8. Calling up the stored characteristic when the job is repeated or when executing a similar or parameterized job

In this context, it is important and efficient for the order processing that the starting temperature of the ink in the ink fountain is detected at the start of printing. This may be via a sensor, if necessary contactless by means of an infrared sensor respectively. For the best possible adjustment, the printing ink can be preheated prior to printing. It should be noted that the color dosing systems in the ink fountain 7 with the ink fountain roller 8th interact hyd rodynamic effects of printing ink attack. Therefore, the ink must not be too tough, so that build up too high pressures and thus mechanical displacement, change the color dosage or lead to leakage of the ink from the ink fountain. This is an important base parameter for the exit temperature and the control limits of the ink fountain roller temperature 8th ,

After the start of the print job is attempted in the context of the method according to the invention, the temperature in the ink fountain 7 by means of temperature control of the ink fountain roller 8th keep as constant as possible. As a result, a uniform color is achieved over the surface of the print, at the same time the ink supply is kept so high that a sufficient saturation of the printed image on the sheet is possible. A change in the tempering characteristic is therefore to be made in small steps in order to avoid disturbances of the coloring in its uniformity over the surface of the sheet.

The inventive method for temperature control is exemplified in the specified scope. Adjustments in the context of the principle of compared to other inking rollers cooler ink fountain roller are therefore within the scope of the method and the associated device possible.

1

plate cylinder

2

transfer cylinder

3

transport direction

4

Impression cylinder

5

dampening

6

inking

7

paintbox

8th

Ink fountain roller

9

vibrator roller

10

distributor roller

11

distributor rollers

12

Inking rollers

TF

tempering Ink fountain roller

T1

tempering distributor roller

T2

tempering distributor roller

T3

tempering distributor roller

T4

tempering distributor roller

T

Temperature System

RF

control valve

R1

control valve

R2

control valve

R3

control valve

Claims (19)

Method for controlling the color transport in an inking unit ( 6 ) of a printing machine, preferably an offset printing press, with a ink fountain roller ( 8th ), a lift ( 9 ) or film roll, other inking rollers ( 11 ), here also distributor rollers are provided, and inking rollers ( 12 ), with at least the ink fountain roller ( 8th ) and several or all of the inking rollers ( 11 ) are coupled to a tempering system (T), characterized in that in at least one inking unit ( 6 ) the temperature of the ink fountain roller ( 8th ) is set to a lower value than the temperature in the roller train of the inking unit by means of the temperature control system (T) ( 6 ) of the ink fountain roller ( 8th ) closest to horizontal inking roller or rollers ( 11 ) and that the temperatures of the ink fountain roller ( 8th ) and the closest to it temperable inking roller or rollers ( 11 ) are controlled independently of each other to predetermined temperature values. A method according to claim 1, characterized in that the temperature of the temperature-controlled inking rollers ( 11 ) is carried out so that on all inking roller ( 11 ) sets a uniform temperature level. A method according to claim 1 or 2, characterized in that the adjustment of temperature differences between respective ink fountain rollers ( 8th ) and the associated temperature-controlled inking rollers ( 11 ) in the different inking units ( 6 ) of a multi-color printing machine is independent of each other. A method according to claim 1 to 3, characterized in that the temperature difference to the temperature of ink fountain rollers ( 8th ) and associated temperable inking rollers ( 11 ) is preselected depending on the ink consumption of an applied printing form. A method according to claim 1 to 4, characterized in that the temperature difference between the ink fountain roller ( 8th ) and associated temperable inking rollers ( 11 ) as a function of the ink layer thickness on one or more temperature-controlled inking rollers ( 11 ) is set. A method according to claim 5, characterized in that the ink layer thickness on one or more of the ink fountain roller ( 8th ) in the roller train nearest inking rollers ( 11 ) is detected metrologically. A method according to claim 1 to 6, characterized in that a color control by Mes solution of one or more color density values of printing inks printed on a printing sheet and change of the temperature difference between the ink fountain roller ( 8th ) and one or more temperature-controlled inking rollers ( 11 ) in the inking unit ( 6 ) whose color has detected a deviation from the target value. A method according to claim 7, characterized in that when metrological detection of a too low color density value of a printing ink on a printed sheet in the corresponding inking unit ( 6 ) the temperature difference between the ink fountain roller ( 8th ) and one, several or all temperature-controlled inking rollers ( 11 ) or that the temperature level of the ink fountain roller ( 8th ) at a constant temperature level of the inking rollers ( 11 ) is reduced. A method according to claim 7, characterized in that at metrological detection of a high color density value of a printing ink on a printed sheet in the corresponding inking unit ( 6 ) the temperature difference between the ink fountain roller ( 8th ) and one, several or all temperature-controlled inking rollers ( 11 ) or that the temperature level of the ink fountain roller ( 8th ) at a constant temperature level of the inking rollers ( 11 ) is increased. A method according to claim 1 to 9, characterized in that temperature differences between the temperature of the ink fountain roller ( 8th ) and the temperature-controlled inking rollers ( 11 ) can be stored as characteristic curves at least as a function of the areal coverage of the ink to be transferred and / or of the chromaticity and / or the density level of the image to be printed and / or further printing technology parameters. Method according to claim 10, characterized in that that the characteristics of the temperature differences in the default the printing press or in the printing process control of the printing press are automatically or manually retrievable. Method according to claim 10 or 11, characterized that the characteristics of the temperature differences during the printing process control the press are customizable and that the changed Characteristic values with regard to printing parameters or order data storable and for new print jobs are available. Inking unit ( 6 ) with a ink fountain roller ( 8th ), a lift ( 9 ) or film roll, other inking rollers ( 11 ), in particular friction and transfer rollers, and inking rollers ( 12 ), wherein at least the ink fountain roller ( 8th ) and a part or all of the inking rollers ( 11 ) and / or transfer rollers are coupled to a temperature control system (T) for carrying out the method according to claim 1, characterized in that the ink fountain roller ( 8th ) an independent of the tempering (T1 to T4) of the other temperature-controlled inking rollers ( 11 ) is assigned to controllable tempering (TF). Inking unit according to claim 13, characterized in that in a multi-color printing machine each ink fountain roller ( 8th ) of the respective inking units ( 6 ) one independent of the tempering (TF) of the other ink fountain rollers ( 8th ) is assigned to controllable tempering (TF). Inking unit according to claim 12, characterized in that the tempering device (TF) of a ink fountain roller ( 8th ) of an inking unit ( 6 ) is connected by means of an independently controllable control valve (RF) with a central temperature control (T). Inking unit according to claim 12, characterized in that the tempering devices (TF) of the ink fountain rollers ( 8th ) of the inking units ( 6 ) of a multicolor printing machine by means of a common temperature control circuit (T) independently of the tempering (T1 to T4) of the other temperature-controlled inking rollers ( 11 ) is connected to the tempering system (T). Inking unit according to one of the preceding claims, characterized in that one or all of the temperature-controlled inking rollers ( 11 ) are formed as distributor rollers. Inking unit according to one of the preceding claims, characterized in that the temperature control medium circuit (T) has control technology with a device for carrying out ink layer thickness measurements on inking unit rollers ( 11 . 12 ) is linked. Inking unit according to one of the preceding claims, characterized characterized in that the temperature control circuit (T) control technology with a device for recording color density values on one Linked sheet is.