EP2993045A2 - Method for feeding ink into a printing machine - Google Patents

Abstract

In a method of feeding ink in a printing machine (1), wherein an inking unit (2) comprises an ink fountain (3) and a roller (4) which together define a storage chamber (5) having a cross-sectional area (6) extending Variegated in vertical direction, a refilling of color in the storage chamber (5) based on a characteristic curve (15), which images the volume of a color supply (7) in the storage chamber (5) as a function of the level height of the ink supply (7) and said Change in the cross-sectional area (6) of the storage chamber (5) taken into account.

Description

The present invention relates to a method for feeding ink in a printing press, wherein an inking unit comprises an ink fountain and a roller, which together define a storage chamber having a cross-sectional area which varies in the vertical direction, wherein refilling of ink into the storage chamber based on a Characteristic curve takes place. Moreover, the present invention relates to a printing machine for carrying out the method.

In offset printing presses, conventional inking units and anilox inking units are used. A conventional inking unit has a paint box with a metering device, which is divided into ink zones. An anilox inking unit has an anilox roller and a squeegee box that work together. For both types of inks, refilling the ink can be done manually or automatically. For manual refilling, the operator may use a spatula to scoop the paint from a can into the ink fountain. For automated refilling, a cartridge can be arranged above the ink fountain, which cartridge is dispensed in a controlled manner as a function of measurement signals from a fill level sensor.

For example, in the DE 100 09 664 A1 a conventional inking described. With this inking unit, the ink consumption is determined and made available to a computer, which uses this data to calculate the color requirements per product unit.

In the DE 10 2013 003 923 A1 For example, a method for supplying ink in an anilox inking unit is described. In this case, the parameters substrate, printing speed and temperature can be taken into account by means of corresponding characteristic curves.

The invention has for its object to provide a further method for supplying color and to create a suitable for performing the method printing machine.

This object is achieved by a method having the features of claim 1 and by a printing machine having the features of claim 10.

In the method for feeding ink in a printing press according to the invention, an inking unit has an ink fountain and a roller, which together define a storage chamber with a cross-sectional area, which cross-sectional area changes in the vertical direction. In the method according to the invention, refilling of ink into the storage chamber takes place on the basis of a characteristic which represents the volume of a supply of ink in the storage chamber as a function of the filling level of the ink supply and takes into account said change in the cross-sectional area of the storage chamber.

In this method, the refilling of the paint can be done manually or automatically. In the case of manual refilling, an indication can be controlled based on the characteristic. The method is suitable for conventional inking and particularly suitable for anilox inking.

In a further development of the method according to the invention there is a non-linear relationship according to the characteristic between the level height and the color volume.

In a further development, a measurement sub-edition is formed by a certain number of sheets of an edition, based on which a color consumption per sheet is calculated programmatically in a computer.

In a further development, on the basis of the calculated ink consumption per arc in the computer, at least one refilling parameter for refilling ink into the storage chamber is programmatically calculated.

In a development, the at least one refill parameter is displayed to the operator on a display.

In a further development, the at least one refill parameter is the sheet number of that sheet of the overlay at which machine refilling must be done at the latest, or is the at least one refill parameter the number of sheets that can still be printed with the ink volume stored in the ink box without refilling.

In a development, the at least one refill parameter is the remaining time during which printing can still be carried out without refilling at a certain printing speed.

In a further development, the at least one refill parameter is a required amount of ink which must be refilled in the ink fountain at the next replenishment.

In a further development, the inking unit is an anilox inking unit, the ink fountain is a squeegee box and the roller is an anilox roller.

The printing machine according to the invention comprises an inking unit and a computer, which comprises a program for carrying out the method according to the invention. The printing machine according to the invention may be an offset printing machine, preferably an offset printing machine for printing on sheets.

Further developments of the invention will become apparent from the following description of exemplary embodiments and the accompanying drawings.

Figur 1:

einen Farbkasten mit einem Start-Füllstand,

Figur 2:

eine Füllstandkennlinie des Farbkastens,

Figur 3:

den Farbkasten mit einem Ist-Füllstand und

Figur 4:

eine ermittelte Füllstandkennlinie.

In this shows:

FIG. 1:

a color box with a start level,

FIG. 2:

a fill level characteristic of the ink fountain,

FIG. 3:

the color box with an actual level and

FIG. 4:

a determined level characteristic.

In FIG. 1 is a detail of a printing machine 1 shown. In the section, an ink fountain 3 and a roller 4 are shown, which are components of an inking unit 2 of the printing machine 1. The inking unit 2 is an anilox inking unit and the roller 4 is an anilox roller. The ink fountain 3 is a doctor blade box with a squeegee 9 and a rear wall 10. In the ink fountain 3, an ink reservoir 7 is stored, which is located in a storage chamber 5, which is bounded by the ink fountain 7 and the roller 4. The rear wall 10 is mounted so as to be adjustable about a swivel joint 11 in order to be able to lift the ink supply 7 by displacement to a level above a cutting edge of the doctor blade 9 by means of the adjustment, which takes place before the start of printing. Above the ink fountain 3, a level sensor 12 is arranged, which is directed to the ink supply 7 in order to measure the level caused by the ink supply 7 level in the ink fountain 3. The level sensor 12 measures the distance between the level sensor 12 and the color surface (color level) and is a non-contact sensor, such as an ultrasonic sensor. The level sensor 12 and a display 13 are connected to an electronic control device 14 which comprises a computer or microprocessor in which a program runs. The controller 14 receives the measurement signals from the level sensor 12 and controls the display 13, which is a touch screen or other screen.

A cross-sectional area 6 of the storage chamber 5 extends perpendicular to the image plane of FIG. 1 , The size of the cross-sectional area 6 changes in the vertical direction because the rear wall 10 and the peripheral surface of the roller 4 do not extend parallel to each other in the vertical direction. The cross-sectional area 6 is the smallest in the region of a constriction between the rear wall 10 and the peripheral surface and, starting from this constriction, becomes larger upward because the rear wall 10 diverges from the peripheral surface.

The reference symbol "M1" denotes a measuring length of the filling level sensor 12 which corresponds to a permissible maximum fill level F1 (cf. FIG. 2 ) of the ink supply 7 corresponds. The reference symbol "M _max " denotes a measuring length which corresponds to a permissible minimum filling level height "F _min " (cf. FIG. 2 ) corresponds. The permissible minimum level height F _min is selected so that the level of the ink supply 7 is always above the cutting edge of the doctor blade 9 in the printing operation. With the filling level decreasing in ink operation due to the ink consumption, the measuring length increases, ie the measured distance between the filling level sensor 12 and the color level of the ink supply 7. From the measured measuring lengths M1, M _max , the level of the filling device F1, F _min calculated. Of course, measuring lengths between M1 and M _max are also measured, and fill levels between F1 and F _{min are} calculated. The maximum fill level F1 is the so-called start level.

In FIG. 2 is a diagram with an abscissa for the filling level and an ordinate for the color volume of the ink supply 7 shown. The characteristic curve 15 in the diagram has been determined by a series of tests, with each measured fill level height-ie, measured measurement length and fill level calculated therefrom-being assigned a different resulting color volume V1, V2. The series of experiments is required to account for the change in cross-sectional area 6. The characteristic curve 15 is stored, for example as a value table, in the computer 8 and is part of the program which runs in the computer 8. By the characteristic curve 15, the relationship between the change in the level height and the color volume change .DELTA.V is mapped.

FIG. 3 shows the arrangement FIG. 1 with a level F2 (cf. FIG. 2 ). With the reduced filling level height F2 corresponds to an enlarged measuring length M2. The difference ΔM between the measuring lengths M1, M2 in FIG. 3 is equal in magnitude to the color volume change ΔV in FIG. 2 ,

In FIG. 4 is the characteristic 15, which in FIG. 2 is shown only schematically, shown in practice-relevant form. The characteristic curve 15 is by stepwise filling of the storage chamber 5 with defined amounts of ink and the reading of the associated Level heights have been determined. Along the curve 15 whose determined curve support points are shown, which may be stored in the form of value pairs in the computer 8.

1. 1. Der Farbverbrauch pro Bogen und der verfügbare Farbvorrat.
2. 2. Die Reichweite bei verfügbarem Farbvorrat.
3. 3. Die Vorhersage des nächsten Nachfüllzeitpunkts (Bogenanzahl und Restlaufzeit).
4. 4. Die Vorhersage der zum nächsten Nachfüllzeitpunkt erforderlichen Nachfüllmenge.

By combining the exact filling height measurement and the characteristic-based information on the available ink supply can be calculated by the computer 8 for a secure production process important information and predictions:

1. 1. The color consumption per sheet and the available ink supply.
2. 2. The range with available color supply.
3. 3. The prediction of the next refill time (sheet count and remaining time).
4. 4. The prediction of the refill quantity required at the next refill time.

The calculator 8 calculates the consumption per sheet as a quotient of the color volume change divided by the number of sheets printed with the color volume difference amount. This number of printed sheets is called a measurement submission and is set. For example, the measurement submission may be set at low area coverage with 1000 arcs and at large area coverage with 300 arcs. In order to improve the prediction results, in the course of printing subsequent to the printing of the measurement sublayer, the decreasing color level may be further measured and the calculated value for color consumption per sheet may be updated. On the basis of the measured after the printing of the measurement part pad level M2 and the characteristic 15 is calculated by the computer 8 of the still available color supply and displayed on the display 13, e.g. on the control panel. The display can be an absolute value in cubic centimeters or as a percentage value and the display can be visualized as a bar chart. At the end of the job, this information is used by the machine operator to assess whether he has to add ink to the ink fountain for a subsequent print job.

The calculation of the range with available ink supply works as follows: The machine operator selects the desired print run height on the control panel. Upon reaching this limit, the printing press stops. 1 automatically. After passing through the measurement sub-edition, the values for the color consumption per sheet and for the color stock still available are available. By the prediction algorithm of the program, which runs in the computer 8, it is determined whether the remaining available ink supply is sufficient to complete the print job before reaching the allowable minimum level height F _min . The range is expressed as the number of printable sheets and is calculated as the quotient of the available ink supply divided by the ink consumption per sheet. On the display 13 can be displayed, for example, that the range is still 4,371 sheets.

The computer 8 makes the prediction of the next Nachfüllzeitpunkts as follows: The prediction algorithm checks on the basis of the preselected number of copies of the print job, with the existing color supply, the edition can be printed without refilling to the end. The difference number of sheets formed from the number of sheets of the preselected number of copies minus the number of sheets of the measuring partial edition must be smaller than the number of sheets of the calculated range. If the available ink supply is smaller than the requirement for the print job, a warning is issued and an indication is made as to which number of sheets of the total print run a refilling must take, so that the permissible minimum fill level height F _{min is} not undershot. For example, with a preselected number of copies of 6,000 sheets, a partial measurement run of 1,000 sheets and a calculated range of 4,371 sheets, the following test would result: 6,000 sheets - 1,000 sheets = 5,000 sheets> 4,371 sheets. A temporary refilling with color is required. The prediction algorithm determines the latest refilling time so that the permissible minimum filling level height F _{min is} not undershot. The refill time can be indicated by an arc number in the run counter of the press or by a time duration. The sheet number is calculated by adding the number of sheets of the already printed measurement sheet to the sheet count of the calculated range. Accordingly, the display 13 indicates to the machine operator at which sheet number the refilling must have taken place at the latest. In the example given, the so-called refill sheet has the sheet number 5.371 (1,000 sheets of the measurement partial edition plus 4,371 sheets of the calculated range). The time of refilling can be done by specifying the refill sheet (sheet number, at which replenishment must be made at the latest) can also be specified by specifying the time, which makes it easier for the machine operator to coordinate his activities with one another. The time is calculated by dividing the calculated range by the print speed. The following information, for example, can be displayed on the display 13. "Refill required in printing unit 2. Sheet number 5.371 - Remaining time 21 minutes 51 seconds". On the display 13, the time of refilling or the remaining time can be displayed by a countdown timer. For reasons of printing technology, it may be expedient to carry out the refilling clearly before reaching the permissible minimum filling level height F _min . For this reason, it may be provided that the filling level height, up to which the range is calculated, can be selected by the machine operator.

The prediction of the refilling quantity required at the time of refilling is calculated in the computer 8 as follows: Depending on the preselected number of copies and the ink requirement, a different amount of ink is required for refilling. If the remaining print is low after the first replenishment, then only the smallest possible but sufficient amount of ink should be topped up in order to minimize the cleaning effort after completion of the print job. If the remaining print is still very large after the first refill, then if possible so much ink should be refilled that the complete print job can be printed to the end. The prediction algorithm contained in the program of the calculator 8 calculates the replenishment amount as follows: The replenishment amount is the product of the color consumption per arc multiplied by the sheet difference calculated from the preselected edition amount minus the refill sheet number. In the given example, where the run length is 6,000 sheets, the refill sheet number is 5,371, and the ink consumption per sheet is 0,1185 cm ³ , a refill amount of 74.5 cm ³ color results according to the formula explained above. This required refill amount is displayed on the display 13.

Vorwahl:

Auflagenhöhe = 6.000 Bogen

Vorwahl:

Messungs-Teilauflage = 1.000 Bogen

Farbvorrat:

518 cm³ = 70 %

Reichweite:

4.371 Bogen

Warnung:

Nachfüllung im Druckwerk 2 erforderlich!

Ab Bogennummer:

5.371

Restlaufzeit:

21 Minuten 51 Sekunden

Erforderliche Nachfüllmenge:

74,5 cm³

In summary, in the case of the exemplary print job with an almost completely filled storage chamber 5, the machine operator, after passing through the measurement partial support, receives the following values on the display 13:

Prefix:

Number of copies = 6,000 sheets

Prefix:

Measurement part pad = 1,000 sheets

Color stock:

518 cm ³ = 70%

Range:

4,371 sheets

Warning:

Refill in printing unit 2 required!

From sheet number:

5371

Remaining time:

21 minutes 51 seconds

Required refill quantity:

74.5 cm ³

Prediction algorithms can also be used in automated refill printing. In the automated refilling by a cartridge, the level sensor 12 with the controller 14 monitors the level height and keeps it constant. If the level drops steadily even though the cartridge has received the command to replenish, the control device 14 or the computer 8 contained therein concludes that the cartridge is empty. A warning message "Cartridge empty" is displayed on the display 13. The warning message "Cartridge empty" activates the prediction algorithm and calculates a prediction, whether the current print job can be finished with the still available color supply. An unnecessary color change can be avoided.

LIST OF REFERENCE NUMBERS

1

press

2

inking

3

paintbox

4

roller

5

storeroom

6

Cross sectional area

7

color stock

8th

computer

9

doctor

10

rear wall

11

swivel

12

level sensor

13

display

14

control device

15

curve

F1

maximum filling level

F2

filling level

F _min

minimum filling level

M1

measuring length

M2

measuring length

M _max

measuring length

.DELTA.M

Measuring length difference

V1

color volume

V2

color volume

.DELTA.V

Color change in volume

Claims (10)

A method of feeding ink in a printing machine (1), wherein an inking unit (2) comprises an ink fountain (3) and a roller (4) which together define a storage chamber (5) having a cross-sectional area (6) extending in the vertical direction wherein replenishment of ink into the storage chamber (6) takes place on the basis of a characteristic curve (15) which images the volume of a color supply (7) in the storage chamber (5) as a function of the fill level of the ink supply (7) and said change the cross-sectional area (6) of the storage chamber (5) taken into account. The method of claim 1, wherein according to the characteristic curve (15) between the filling level and the color volume is a non-linear relationship. The method of claim 1 or 2, wherein by a certain number of sheets of a support, a measurement part pad is formed on the basis of a color consumption per sheet is calculated programmatically in a computer (8). A method according to claim 3, wherein on the basis of the calculated ink consumption per sheet in the computer (8) programmatically at least one refilling parameter for the refilling of ink into the storage chamber (5) is calculated. The method of claim 4, wherein the at least one refill parameter is displayed to the operator on a display (13). The method of claim 4 or 5, wherein the at least one refill parameter is the sheet number of that sheet of the edition at the machine pass refilling must be latest, or the number of sheets that still printed with the in the ink fountain (3) stocked ink volume without refilling can be. The method of claim 4 or 5, wherein the at least one refill parameter is the remaining time during which can be printed at a certain printing speed without refilling. The method of claim 4 or 5, wherein the at least one refill parameter is a required amount of ink, which must be refilled in the next refill in the ink fountain (3). Method according to one of claims 1 to 8, wherein the inking unit (2) is an anilox inking unit, the ink fountain (3) is a squeegee box and the roller (4) is an anilox roller. Printing machine having an inking unit (2) and a computer (8), which comprises a program for carrying out the method according to one of claims 1 to 9.

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