Delivering a Whiter White in Package Printing - MacDermid Graphics ...

0 downloads 83 Views 814KB Size Report
pass. Today's “standard” system often requires the use of multiple white stations on press, or more expensive, refor
Delivering a Whiter White in Package Printing A White Paper

Delivering a Whiter White in Package Printing

Executive Summary

“Digital

MWW is a flexographic printing plate that brings unparalleled print performance to white ink delivery, providing dramatically reduced mottle and improved opacity - all in one pass.”

Digital MWW is a flexographic printing plate that brings unparalleled print performance to white ink delivery, providing dramatically reduced mottle and improved opacity- all in one pass. Today’s “standard” system often requires the use of multiple white stations on press, or more expensive, reformulated inks just to achieve acceptable values. The use of Digital MWW in combination with the LUX® exposure process and the WhiteFXTM ink transfer solution developed by CSW, Inc., allows for dramatic improvements in print quality and reduces overall white ink consumption.

Part I: The Beginning Digital MWW was an outcome of a designed experiment conducted by the combined research departments of MacDermid Graphics Solutions and CSW, Inc. The “White Print Matrix” project was prepared with a technical presentation at FFTA Info*Flex in mind. In conceiving the project, MacDermid and CSW sought to converge the capabilities of LUX® flattop dot technology, advanced surface engineering techniques, and the on-press knowledge for printing background whites. The end result was the experimental outline shown in Table 1. Table 1: Experimental Layout for the White Print Matrix

Delivering a Whiter White in Package Printing

The print layout shown in Figure 1 was selected in order to optimize the efficiency and objectivity of the study. The study was conducted on a 50” wide web press, utilizing four printing decks, three anilox types, and multiple sleeves. The white ink formulation was kept constant, with a closely monitored and maintained viscosity typical for high speed production. Shrinkable polyethylene was chosen for the substrate due to its common use in wide web production. In addition, an overprint of cyan was added to the study in order to evaluate the potential impact of background white on other aspects of the print. Figure 1: Print Layout

The final print layout is shown below in Figure 2. During this study, three different plate and tape hardnesses were evaluated, in addition to three selections of anilox rolls (250, 360 and 550). Four different screening methods were employed on two different types of digital plates, which included LUX® and standard exposure methods.

Delivering a Whiter White in Package Printing

Figure 2: Test Form

The Results After running 270 different combinations, the results were analyzed for optimum mottle and opacity, with a “standard” method as reference. This standard method was a double print white using a medium durometer, conventionally exposed digital plate. It became evident early on that the LUX® exposed plates greatly enhanced the impact of surface screening methodologies, an observation seen in other print applications as well. The pictures shown in Figure 3 highlight the various levels of print quality seen in this study. As shown, the study was indeed effective in including numerous “poor” quality results in addition to remarkably high quality results as well.

Delivering a Whiter White in Package Printing

Figure 3: Comparison of Various Mottle Levels Observed in the White Print Matrix

In addition to the noticeable impact on the white samples alone, the inclusion of the overprint cyan showed what a dramatic impact that the background white can have on other colors as well. Figure 4 shows the same four levels in the presence of the overprint color. Figure 4: Impact of Background White Mottle on Overprint Cyan

Delivering a Whiter White in Package Printing

Overall, significant improvements were noted in both opacity and mottle, but the question remained as to how to select the best of the best. The table below shows the weighted outcome of mottle using values less than 6. It should be noted that white poly has a mottle value less than 1. Out of the 270 scenarios evaluation, a total of 20 samples met the criteria of mottle less than 6. Furthermore, all of these values were obtained with the 250 and 360 anilox rolls, with 60% of the optimized results belonging to the 250 anilox. Table 2: Final Mottle Tabulation MOTTLE

250 ANILOX - 7.2 bcm

360 ANILOX - 5.0 bcm

550 ANILOX - 2.5 bcm

TOTALS

0 - 2.99

OPTIMUM

6

OPTIMUM

3

OPTIMUM

0

9

3 - 5.99

GREAT

6

GREAT

5

GREAT

0

11

6 - 10.99

GOOD

10

GOOD

9

GOOD

0

19

11 - 15.99

BETTER

19

BETTER

11

BETTER

1

31

16 - 19.99

NORMAL

19

NORMAL

9

NORMAL

0

28

20 - 25.99

POOR

18

POOR

16

POOR

1

35

26 - 29.99

BAD

10

BAD

19

BAD

2

31

30+

UNUSABLE

2

UNUSABLE

18

UNUSABLE

86

106

90

270

TOTALS

90

90

Similarly, the opacity values were tabulated and are shown in Table 3. In this case, samples with opacity values greater than 54 were highlighted, yielding a final total of 48 samples. Of these 48, 47 were attributable to the highest volume anilox configuration, with only one sample belonging to another anilox roll selection.

Delivering a Whiter White in Package Printing

Table 3: Final Opacity Tabulation OPACITY

250 ANILOX - 7.2 bcm

360 ANILOX - 5.0 bcm

550 ANILOX - 2.5 bcm

TOTALS

>55

OPTIMUM

4

OPTIMUM

0

OPTIMUM

0

4

54 - 55.9

GREAT

43

GREAT

1

GREAT

0

44

52 - 53.9

GOOD

39

GOOD

23

GOOD

0

62

50 - 51.9

BETTER

4

BETTER

40

BETTER

0

44