DD276455A1 - LIFTING COLOR FOR QUICK-LAYING ROLL ROTATION PRINTING MACHINES - Google Patents

Abstract

The invention relates to a lifting inking unit for high-speed web-fed rotary printing presses with a liftable in the lift mode between a ink fountain and a transfer roller roller. The invention has for its object to interpret the influence of Farbuebertragung the ink supply system so that can be driven with optimum adaptation of the ink metering to the ink needs of the printing plate and the Speicherkapazitaet the Farbverreibsystems and with sufficient dynamic behavior of the lift roller with maximum machine speed. According to the invention, the object is achieved in that the drive means for the lifter cam gear is an electric motor and that a control device for speed control of the electric motor is provided. Fig. 1

Description

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In the known lift inking the Heberkurvenschei.be a gear drive through the main drive shaft of Printing machine driven with a fixed gear ratio. Accordingly, the Hebertaktziihl - a change

single lifter stroke corresponds to a single revolution of the lifter cam - in the same, ratio wio the

Plate cylinder speed. Connected to the relatively low dynamic limit of the vibrating squeegee roller gives us a

upper limit speed for the mileage of the printing press.

When determining the constant speed ratio n _H / n _O z, it must be ensured that, on the one hand, at the upper limit of the

provided speed range for the printing plate cylinder, the dynamic behavior of the vibrating lifting roller is met (upper limit of the speed ratio) and on the other hand, no discernible periodic color depletion in the pressure occurs (lower limit).

As an alternative to the discontinuous lifting inking unit is the continuous working inking unit for

high-speed rotary presses have been developed.

However, this inking unit is extremely sensitive in setting and indifferent in the color guide. Besides, it is in Difference to the squeegee unit not able to color dampening emulsion from the Farbverrelbsystem in the color box

attributed what u. a. with lack of too much building of the color-dampening emulsion on the inking rollers and thus necessary interruptions of the production for the purpose of washing «may be connected.

The specific disadvantages of the film inking unit * led to the development of the combined lift film inking unit, for example

a convertible lift / film inking unit - see published patent application DE 3008980. Here, the printer has to decide before processing a print job, whether at full machine speed with the film inking unit or at reduced

Machine speed is printed with the elevator inking unit. A disadvantage is the expense associated with the pivoting mechanism and the adjusting device. In movie mode, it remains

the disadvantages listed above. In lift mode is because of inevitably connected to the machine drive

Actuator of the lift cam disc an optimal adjustment of the color dosage to the order-dependent color requirement not

possible and the machine speed is limited by the dynamic limit of the lifting roller.

Object of the invention

The aim of the invention is to further develop a lifting inking unit for high-speed roll Rotat'onsdruckmaschinen so that machine speeds can be driven above an associated with the dynamic limit of the elevator inking upper limit speed insofar as the quality requirements for color printing allow.

Explanation of the essence of the invention

Dor invention is the object of the influencing variables of color transfer of the ink supply system of a Heberforbwerkes designed so that with optimum adaptation of the ink metering to the ink needs the printing plate and the storage capacity of the Farbverreibsystems .sowie can be driven with sufficient dynamic behavior of the pivotable lifting roller with a maximum machine speed ,

According to the invention the object is achieved in that the drive means for the lifter cam gear is an electric motor for continuous rotational movement and that a control device for speed control of the electric motor is provided. The control device comprises a first measuring member for measuring the printing plate cylinder speed, a generator for the drive speed of the lifter cam gear, a summing element for the signal of the first measuring element and the signal of the encoder, a second measuring element for Messon the drive speed of the Heberkurvengetriebesm, a comparison element for the signal of the summing and the signal tfas second measuring element, a regulator and an actuator.

By means of the control device for speed control of the drive means for the Heberkurvengetriebe electric motor «is the ratio of the drive speed of the Heberkurvengetriebes to the speed of the pressure plate cylinder adjustable and constantly adjustable with changes in the speed of Dpjckplattenzylinders. In an embodiment of the invention, the drive means for the lift curve / igetriebe certain electric motor is a three-phase asynchronous and the actuator is a frequency converter. This allows the combination of the advantages of regulated DC motors mi ¹ ; the unpretentiousness of three-phase short-circuit motors.

In a further embodiment of the invention, a single control device for speed control of the electric motor for driving control of all lifting cam gear (5) of a printing unit or a printing machine is designed. 8eim setting the conditions for continuous pressure is first by means of the encoder for the drive speed of the lifting cam gear, the Hubertaktzahl - a lifter stroke corresponds to one revolution of the cam of the lifting cam gear - has been set in a defined ratio to the speed n _O z de ι plate cylinder. Since the ratio n _H / n _O z is kept constant by the control device for regulating the speed of the drive of the lifting cam gear, the lifting cycle number n _{H increases} in the same ratio as the printing plate cylinder rotational speed n _O z ·

If the pressure plate cylinder speed n _O z be further increased, so by means of the encoder door to reduce the drive speed of the lift curve of the speed ratio n _H / n _O z because of the dynamic limit of the elevator inking, ie, the number of attributable to a single Hebertaktperiode pressure cylinder revolutions increases. As can be seen from the above-mentioned equation of determination, the amount of ink supplied per squeeze-stroke period increases proportionally-that is, the ink supply remains adapted to the color requirement. The adjustment limit is exceeded when a recognizable or for the respective print order unacceptable color variation occurs within the attributable to a single Hebertaktperiode printing sequence.

, Dor particular advantage of the invention further development of the Heberfarbwerkee is the ability to realize by targeted adjustment of the ratio Πη / ποζ the Hubertaktzahl to printing plate cylinder speed for a variety of print jobs a high mileage of the rotary web press with satisfied quality criteria. In addition, in the range of reduced machine speed, it is possible to meet the highest demands on the uniformity of the ink application on the printing plate.

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The invention is not abandoned by the fact that the control device for speed control of the drive means for dns lift curves driven drives electric motor realized a limit control that keeps constant from speed ratio n _H / n _DZ until reaching the associated with the dynamic limit of the lift roller limit value for the Hebertaktzahl and, moreover, by keeping the speed of the stroke constant, the speed ratio n _H / n _{M is} decreased. The invention is also transferable to lift dampeners.

embodiment The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing shows Fig. 1: the schematic representation of a lift inking unit with an inventive arrangement for driving and for

Speed control of the lift curve transmission, Fig. 2: the schematic representation of a control loop for speed control of the lift curve drive.

The siphon has an ink fountain 1 arranged on a continuously drivable ink fountain roller 2 and a in Lifting operation between this and a subordinate - not shown - Farbverreibsystem feeding color Transfer roller 3 vorschwenkbare lift roller 4. The pivoting movement of the lifting roller 4 is over Lifting cam gear 5 continuously drivable. According to the invention, the drive means for the lifting cam gear 5 is an electric motor for continuous rotational movement, in

This embodiment, a Drehstromaiynchronmotor 6. The control device for speed control of

Drehstromasynchronmotors - known per se and according to the invention for speed control of the three-phase asynchronous motor β

used, comprises a first measuring member 7 for measuring the pressure plate cylinder speed, an encoder 8 for Antriebsdrenzahl the lifting cam gear 5, a summing member 9 for the signal of the first measuring element 7 and the signal of the encoder 8, second measuring element 10 for measuring the driving speed of the lifting cam gear 5, a Comparative element 11 for the sign of the

Summier 9 and the signal of the second measuring element 10, a controller 12 for the speed and one as an actuator

certain electronic frequency converter 13.

In a known embodiment of the frequency converter 13, the functional units control part 13.1 and Power section 13.2 provided. The management section 13.2 contains the components Mains rectifier, DC intermediate circuit and Inverter. The Control part 13.1 realized in a known manner in cooperation with the power section 13.2, the three-phase change spun

with controllable output frequency, whereby to ensure a constant magnetic flux in the

Drehstromasynchronmotor in the preferred control range of the output frequency at the same time kept the ratio U _s / fs constant When setting the continuous pressure conditions, first by means of the encoder 8 for the drive speed n _H of Lifting cam gear 5, the drive speed n _H in a defined ratio to the speed n _{DZ of} the printing plate cylinder,

for example, in the ratio 1: 5, has been set. Since this speed ratio by the control device for

Speed control of the drive of the Heberkurvengctriebes 5 is kept constant, grows when starting the Printing press the Hebertaktzahl n "in the same ratio as the plate cylinder speed n _O z. After reaching the Dynamic limit of the lifting roller 4 is a further increase of the printing plate cylinder speed n _O j with reduction dus Rotational ratio n _H / n _DZ possible. With the encoder 8 for the input speed n _{H of} the lift cam 5

For example, a speed ratio n _H / n _0Z of 1: 7 is set, that is, the number of pressure cylinder revolutions occurring on a single lifter stroke period increases from 5 to 7, and the mileage of the printing press may be exceeded

Exceeding the dynamic limit of the squeegee roller 4 can be increased by a maximum of 20%. The adjustment limit is! then exceeded if an identifiable or unacceptable for the respective print job Color variation occurs within the printing sequence attributable to a single lifter clock period. By a targeted adjustment of the speed ratio n ₍₍ / n _oz can, taking into account for the respective Drucktiuftrag

valid quality criteria a high mileage of the printing press can be realized.

Claims (3)

1. Lifting inking unit for high-speed rotary printing presses with a arranged on the ink fountain continuously drivable ink fountain roller and a lifting operation between this and a subordinate inking rollers ink feeding transfer roller pivotable lift roller, the drive of the ink fountain roller speed adjustable and the pivoting movement of the lift roller via a cam mechanism is continuously driven CHARACTERIZED IN THAT the driving means for the lifting cam gear (5) is an electric motor (6) for continuous rotary motion and that one of a first measuring member (7) for measuring the rotational speed (n _DZ ) of the printing plate cylinder, an encoder (8) for the Drive speed (n _H ) of the lifting cam gear (5), a Summiergiied (9) for the signal of the first measuring element (7) and the signal of the encoder (8), a second measuring element (10) for measuring the drive speed (n _H ) of the lifting cam gear (5), a comparator (11) f for the signal of the summing element (9) and the signal of the second measuring element (10), a controller (12) and an actuator (13) existing control device for speed control of the electric motor (6) is provided, wherein the ratio of the drive speed (n _H ) of the lever cam mechanism (5) to the speed (n _D z) of the printing plate cylinder adjustable and boi changes in the speed (n _DZ ) of the printing plate cylinder is constantly controllable. 2. Lifting inking unit according to claim 1, characterized in that the drive means for the Heberkurvengetriebe (5) certain electric motor (6) is a three-phase asynchronous motor and the actuator (13) is a frequency converter. 3. Lifting inking unit according to claim 1, characterized in that a control device for speed control of the electric motor (6) for driving control of all Heberkurvengetriebe (5) of a printing unit or a printing machine is designed. For this 2 pages drawings Field of application of the invention The invention relates to a squeegee for sctviellaufende web-fed rotary printing machines with a arranged on a color box continuously drivable ink fountain roller and a siphon between this and a subordinate inking rollers feeding ink transfer roller pivoting squeegee roller, the drive of the ink fountain roller is drehzahleinstellbar and the pivoting movement of the squeegee on a Cam mechanism is continuously driven. Characteristic of the known state of the art As is known, the lifting roller performs a swinging motion. In turn, it lays down to the ink fountain roller and the ersto ink transfer roller ati, over the entire width of the vibrator roller, a narrow color strip of thickness s _M , the length I _H (corresponds to the machine printing width) and dor width b _{H is} transmitted. The Farbverreibsystem per Hebordakt (Hoberschwingung) zuzugo fed amount of ink corresponds to the volume of the transferred from the vibrating roller color strip. With fixed ink layer thickness s _H , the amount of ink supplied is the color stripe width b _H proportional (disturbing influences vemachläcsigt). For the absolute value of the color stripe width bn applies , ..
b _H = U _D with the circumference Uo of the ink fountain roller, the ratio n _o / n _O z of the speed of the ink fountain roller to the speed of the pressure plunger cylinder, the ratio n _H / n _{02 of} the speed of the lifter cup to the speed of the printing plate cylinder and the duty ratio Atn / tn of the lifter roller (ratio of Touch time to the period of the lifter cycle period). As can be seen from this equation of determination, the quantity of ink supplied to the inking unit with a single stroke changes proportionally to the speed ratio ηχ / ποζ. This means that, neglecting speed-dependent stoiches at each speed ratio n _H / n _w, the ink feed per squeeze-stroke period is exactly matched to the color requirement per squeeze-stroke period. However, with the number of printing cylinder rotations attributable to a single lifter clock period, the likelihood of color variations in the print image of the printing sequence attributable to the single stroke rate port increases - an effect of the discontinuous ink transfer from the ink fountain roller to the inking system at the inking unit. This so-called color depletion which occurs periodically with the Hobertaktperiody depends on the ratio of the flow rate to the storage amount of the ink in Farbverreibsystem, the flow amount of the printing plate, the ink and the substrate depends and the storage amount is a constant of the Farbverreibsystems. It follows that the speed ratio limit n ₍ | / noz) associated with detectable color depletion may be different for different print jobs.