LITHO STRIP HAVING FLAT TOPOGRAPHY AND PRINTING PLATE PRODUCED THEREFROM

Abstract

The present disclosure provides an aluminium alloy strip for lithographic printing plate supports, which has a rolled-in surface topography on one strip surface. Further, a method is disclosed for manufacturing the aluminium alloy strip and a printing plate for lithographic printing, with a printing plate support made of aluminium alloy. The object of proposing an aluminium alloy strip for lithographic printing plate supports is that it provides a long service life in the printing process and is roughened with less charge support entry. This is achieved in that the surface of the aluminium alloy strip has a mean peak number measured perpendicular to the rolling direction of the aluminium alloy strip.

Claims

1. Use of an aluminium alloy strip for manufacturing lithographic printing plate supports or printing plate for the waterless offset printing, which has a rolled-in surface topography on at least one strip surface, wherein the surface of the aluminium alloy strip has a mean peak number RPc measured perpendicular to the rolling direction of the aluminium alloy strip of ≤50 cm.sup.−1, preferably ≤45 cm.sup.−1 or particularly preferably ≤40 cm.sup.−1, wherein c1=+0.25 μm and c2=−0.25 μm were selected as cutting lines for the RPc measurement and the mean peak number RPc is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein within the measuring areas the arithmetic mean value of the profile parameter RPc perpendicular to the rolling direction is calculated from the profile sections of the areal measurement available per measuring area perpendicular to the rolling direction and the arithmetic mean is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

2. An aluminium alloy strip for lithographic printing plate supports, which has a rolled-in surface topography on at least one strip surface, wherein the aluminium alloy strip has the following composition: 0.02 wt.-%≤Si≤0.50 wt.-%, preferably 0.02 wt.-%≤Si≤0.25 wt.-%, 0.2 wt.-%≤Fe≤1.0 wt.-%, preferably 0.2 wt.-%≤Fe≤0.6 wt.-%, Cu ≤0.05 wt.-%, preferably ≤0.01 wt.-%, Mn ≤0.3 wt.-%, preferably <0.1 wt.-%, particularly preferably ≤0.05 wt.-%, 0.05 wt.-%≤Mg≤0.6 wt.-%, preferably 0.1 wt.-%≤Mg≤0.4 wt.-%, Cr ≤0.01 wt.-%, Zn ≤0.1 wt.-%, preferably ≤0.05 wt.-%, Ti ≤0.05 wt.-%, residual Al and impurities individually maximum 0.05 wt.-%, in total maximum 0.15 wt.-%, the surface of the aluminium alloy strip has a mean peak number RPc measured perpendicular to the rolling direction of the aluminium alloy strip of ≤50 cm.sup.−1, preferably ≤45 cm.sup.−1 or particularly preferably ≤40 cm.sup.−1, wherein c1=+0.25 μm and c2=−0.25 μm were selected as cutting lines for the RPc measurement and the mean peak number RPc is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein within the measuring areas the arithmetic mean value of the profile parameter RPc perpendicular to the rolling direction is calculated from the profile sections of the areal measurement available per measuring area perpendicular to the rolling direction and the arithmetic mean is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

3. The aluminium alloy strip of claim 2, wherein the surface of the aluminium alloy strip has a mean peak height Rp of a maximum of 1.1 μm, preferably 0.45 μm to 1.1 μm and the peak height Rp is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein within the measuring areas the arithmetic mean value of the profile parameter Rp perpendicular to the rolling direction is calculated from the profile sections of the areal measurement available per measuring area perpendicular to the rolling direction and the arithmetic mean is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

4. The aluminium alloy strip of claim 2, wherein the mean contact area portion Smr (c=+0.25 μm) of the surface portions of the surface of the aluminium alloy strip oriented in the rolling direction in % is maximum 5%, maximum 4%, or maximum 3.5%, wherein only the surface portions are taken into account, which follow a Fourier transformation of the surface in the rolling direction and the average contact area portion Smr (c=+0.25 μm) is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein the arithmetic mean value is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

5. The aluminium alloy strip of claim 2, wherein the thickness of the aluminium alloy strip is 0.10 mm to 0.5 mm, preferably 0.10 mm to 0.4 mm.

6. The aluminium alloy strip of claim 2, wherein the aluminium alloy strip has a work hardened state.

7. A method for manufacturing the aluminium alloy strip for lithographic printing plate supports of claim 2, in which a rolling ingot is cast from an aluminium alloy for lithographic printing plate supports, before the hot rolling of the rolling ingot is optionally preheated or homogenised, the rolling ingot is hot-rolled into a hot strip and the hot strip is then cold-rolled to the final thickness with or without intermediate annealing, wherein a work roll is used in the last cold rolling pass, which has an average roughness Ra according to DIN ISO 4287 of less than 0.18 μm, preferably less than 0.17 μm or preferably at most 0.15 μm.

8. The method of claim 7, wherein a work roll is used in the last cold rolling pass which has a mean roughness Ra according to DIN ISO 4287 of at least 0.07 μm, preferably at least 0.10 μm.

9. The method of claim 7, wherein the degree of unrolling in the last cold rolling pass is at least 20%, preferably at least 30%.

10. The method of claim 7, wherein the degree of unrolling in the last cold rolling pass is a maximum of 65%, preferably a maximum of 60%.

11. A printing plate for lithographic printing having a printing plate support made from an aluminium alloy, in particular manufactured from the aluminium alloy strip of claim 2, wherein at least the surface of the printing plate support facing the imaging layer after the electrochemical roughening of the printing plate support has an average contact area portion Smr (c=+0.25 μm) of the surface portions oriented in the rolling direction less than 5%, less than 4.5%, or at most 4%, wherein only the surface portions resulting after a Fourier transformation of the surface in the rolling direction are taken into account and the average contact area portion Smr (c=+0.25 μm) is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein the arithmetic mean value is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

12. The printing plate of claim 11, wherein at least the surface of the printing plate support facing the imaging layer after the electrochemical roughening of the printing plate support is a ratio of the mean peak height to the mean trough depth Rp/Rv of a maximum of 0.45, preferably a maximum of 0.4 and the mean peak height Rp and the mean trough depth Rv are determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein within the measuring areas the arithmetic mean value of the profile parameters Rp and Rv perpendicular to the rolling direction is calculated from the profile sections of the areal measurement available per measuring area perpendicular to the rolling direction and wherein the arithmetic mean value is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

13. The printing plate of claim 11, wherein after the electrochemical roughening of the printing plate support, at least the surface facing the imaging layer has a mean peak height Rp of less than 1.2 μm, at most 1.1 μm or at most 1 μμm and the peak height Rp is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein within the measuring areas the arithmetic mean value of the profile parameter Rp perpendicular to the rolling direction is calculated from the profile sections of the areal measurement available per measuring area perpendicular to the rolling direction and the arithmetic mean is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

14. The printing plate of claim 11, wherein at least the surface of the printing plate support facing the imaging layer achieves an aspect ratio of the surface texture Str in accordance with DIN EN ISO 25178 of at least 50% after electrochemical roughening with a charge support entry of at least 500 C/dm.sup.2 and the aspect ratio of the surface texture Str is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein the arithmetic mean value is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

15. The printing plate of claim 14, wherein at least the surface of the printing plate support facing the imaging layer achieves an aspect ratio of the surface texture Str according to DIN EN ISO 25178 of at least 20% after electrochemical roughening with a charge carrier entry of at least 400 C/dm.sup.2 and the aspect ratio of the surface texture Str is determined from an optical areal measurement of three measuring areas of at least 4.5 mm×4.5 mm with a confocal microscope having a lateral measuring point spacing of 1.6 μm or less, wherein the arithmetic mean value is calculated from the three measuring areas for the parameter, wherein the measurement data preparation is carried out by a shape adjustment with a second order polynomial (F-filter) and a Gaussian filter with λc=250 μm as waviness filter without filtering of the fine roughness.

16. A printing plate for waterless offset printing comprising a printing plate support manufactured from the aluminium alloy strip of claim 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The invention is explained further by means of embodiments. Reference is made to this end to the following tables and the drawing. In the drawing

[0054] FIGS. 1-4 show measuring surfaces of optically measured comparison litho strips, which were electrochemically roughened with different charge carrier entries in a false colour representation of the height values;

[0055] FIGS. 5-8 show measuring surfaces of optically measured litho strips according to the invention, which were electrochemically roughened with different charge carrier entries in a false colour representation of the height values; and

[0056] FIG. 9 shows a material proportion curve in the form of an Abbott curve for determining the contact area portion Smr (c).

DETAILED DESCRIPTION

[0057] The litho strips, the measuring surfaces of which are shown in FIG. 1-8, were produced from a rolling ingot made of an aluminium alloy with the following composition:

0.02 wt.-%≤Si≤0.50 wt.-%, preferably 0.02 wt.-%≤Si≤0.25 wt.-%, 0.2 wt.-%≤Fe≤1.0 wt.-%, preferably 0.2 wt.-%≤Fe≤0.6 wt.-%,
Cu ≤0.05 wt.-%, preferably ≤0.01 wt.-%,
Mn ≤0.3 wt.-%, preferably <0.1 wt.-%, particularly preferably ≤0.05 wt.-%, 0.05 wt.-%≤Mg≤0.6 wt.-%, preferably 0.1 wt.-%≤Mg≤0.4 wt.-%,

Cr ≤0.01 wt.-%,

[0058] Zn ≤0.1 wt.-%, preferably ≤0.05 wt.-%, Ti ≤
0.05 wt.-%,
residual Al and impurities individually at most 0.05 wt.-% in total at most 0.15 wt.-%.

[0059] The manufacture by casting a rolling ingot, homogenising the rolling ingot at 450 to 610° C. for at least 1 h, hot rolling the rolling ingot to a hot strip with a thickness of approx. 2-7 mm and cold rolling of the hot strip with or without intermediate annealing to final thickness.

[0060] In the last cold rolling pass, in the litho strips according to the invention of FIGS. 5-8 a work roll is used, the surface topography of which has an arithmetic mean roughness Ra in accordance with DIN ISO 4287 of less than 0.18 μm, preferably a maximum of 0.17 μm or a maximum of 0.15 μm. The mean trough depth Rv of the surface of the work rolls of the embodiments according to the invention was max. 1.2 μμm.

[0061] The comparison litho strips in FIGS. 1-4, on the other hand, were cold-rolled with a work roll in the last cold rolling pass, which has an arithmetic mean roughness Ra of 0.22 μμm-0.25 μμm. At a maximum of 1.6 μm, the mean trough depth Rv was also higher than in the work rolls to be used according to the invention. The sheets produced in this way were electrochemically roughened in HCl as electrolytes with various charge carrier entries from 400 C/dm.sup.2 to 800 C/dm.sup.2.

[0062] The height values of the optically measured measuring surface areas are shown in FIGS. 1-8 in false colours, wherein depressions are assigned grey to black colour shades and elevations assigned light grey to white grey tones. With the human eye, differences can already be detected on the measuring surface areas shown in this way in the not roughened state. Thus, the litho strips according to the invention show a significantly less structured surface in the rolling direction. This effect becomes stronger with increasing roughening. Further measurements were carried out on litho strips of the embodiments a, b, c, d and m as well as the comparative examples f, g, h, which had aluminium alloy compositions according to Table 1.

[0063] All measured values Rp, RPc, Rv, Ra, Smr and Str of the embodiments and comparative examples were optically measured on three measuring surface areas of the size 4.5 mm×4.5 mm with a confocal microscope and determined with analysis software (Digital Surf MountainsMap®). The measuring surface areas were randomly arranged on the strips and the printing plate supports in a DIN A4 sized area. The corresponding points on the strips were free of surface damage. The arithmetic mean of the three measuring surface areas for each parameter was calculated, wherein within the measuring surface areas the profile parameters perpendicular to the rolling direction Rp, RPc, Rv, Ra were calculated as arithmetic mean values. The measurement data was prepared by means of a shape compensation with a second order polynomial (F filter). A Gaussian filter with λc=250 μm was used as a waviness filter. The fine roughness was not filtered.

[0064] The litho strips a, b, c, d and m were manufactured identically by the above-mentioned method starting with the casting of a rolling ingot, homogenisation of the rolling ingot, hot rolling of the rolling ingot and cold rolling of the hot strip at the end thickness with intermediate annealing (H18) and without intermediate annealing (H19).

[0065] The resulting thicknesses, material conditions and arithmetic mean roughness values Ra of the surfaces of the resulting litho strips are specified in Table 1. The different roller topographies used for the last cold rolling pass can be found in Table 7.

[0066] The litho strips according to the invention were therefore cold-rolled in the last cold rolling pass with a work roll with a roller surface, which according to Table 7 had an arithmetic mean roughness Ra of 0.11 μm to 0.17 μm, with the indicated degree of unrolling. The mean trough depth Rv was measured with less than 1.2 μμm. At 40% to 55%, the degree of rolling was in the range of at least 20% according to the invention. Furthermore, the degree of rolling was also below 60% or below 65% at a maximum of 55%, so that good surface properties were achieved with the lowest possible number of roll passes.

[0067] The arithmetic mean roughness value Ra of the roller surface of the work roll in the last cold rolling pass of the comparison strips was between 0.22 μm and 0.25 μm. At a maximum of 1.6 μm, the mean trough depth Rv was also significantly higher than in the work rolls used according to the invention.

[0068] In the manufacture of the embodiments according to the invention, contrary to the previous opinion of the experts, a stable production process has been shown without disruptions occurring during cold rolling due to slippage between the cold rolling and the litho strip to be rolled.

[0069] First differences between the comparison strips and the litho strips according to the invention were found in the arithmetic mean roughness values Ra of the litho strips a, b, c, d and m according to the invention. At 0.09 μm to 0.11 μm, these were significantly below the values of the comparison examples f, g and h with approx. 0.19 μm. These values of the arithmetic mean roughness value Ra perpendicular to the rolling direction result from the provision of a roller surface, which has an arithmetic mean roughness value Ra of less than 0.18 μm.

[0070] The aluminium strips a, b, c, d and m according to the invention also showed, as shown in Table 2, mean peak numbers RPc measured perpendicular to the rolling direction of significantly less than 50 cm.sup.−1. The comparison strips with a mean number of peaks RPc of more than 68 cm.sup.−1 were, on the other hand, significantly above the results of the aluminium strips according to the invention.

[0071] At a maximum of 0.74 μmμm, the mean peak height Rp in the aluminium alloy strips according to the invention was also significantly below the mean peak heights Rp of the comparison strips, which had at least 0.88 μm as the mean peak height Rp, wherein the low mean peak height Rp is attributed to the lower trough depth Rv of the roller surface.

[0072] The mean contact area portion Smr (c=+0.25 μμm) of the surface portions oriented in the rolling direction was significantly lower in the embodiments according to the invention. FIG. 9 shows by way of example how the contact area portion Smr (c) can be determined from a material proportion curve in the form of an Abbott curve for a value c. The value c=0 results as can be seen in FIG. 9 with a material proportion of 100%. The c-value is read on the Z-axis, which corresponds to a height value of the surface topography. To determine the contact area portion Smr (c) the intersection point of the material proportion curve is determined with the straight line Z=c and the corresponding material proportion is read on the X axis.

[0073] In order to determine the mean contact area portion Smr (c=+0.25 μm), as explained above, optical measurement results are subjected to a roughness measurement of a Fourier transformation and only the surface portions oriented in the rolling direction are back-transformed. From the back-transformed surface data, a material proportion curve, as shown in FIG. 9 and a value for the contact area portion Smr (c=+0.25 μm) is determined. From the contact area portions Smr (c=+0.25 μm) determined on three measuring surfaces of the surface portions oriented in the rolling direction the arithmetic mean was then calculated to determine the mean contact area portion Smr (c=+0.25 μm).

[0074] The mean contact area portions Smr (c=+0.25 μm) of the surface portions of the aluminium alloy strips according to the invention oriented in the rolling direction were at a maximum of 3.79% significantly below 5%. While the contact area portion Smr (c=+0.25 μm) of the surface portions of the comparison strips oriented in the rolling direction was at least 8.09% more than twice as high as the maximum measured mean contact area portion Smr (c=+0.25 μm) of the surface portions of the aluminium strips according to the invention oriented in the rolling direction.

[0075] The printing plate supports manufactured from aluminium strips according to the invention showed a significantly improved service life in printing when using “development on press” coatings compared to the comparative examples. This is attributed to the differences in the surface topography. It is assumed that the same also applies to printing plates for waterless offset printing.

[0076] The properties of the aluminium strips in electrochemical roughening were tested with HCl as electrolyte, wherein different charge support entries were used. The concentration of the electrolyte was 6 g HCl per litre and 1 g/L Al.sub.3+ in the form of AlCl.sub.3 at 25 to 30° C. with a current density of 20 A/dm.sup.2 and alternating current.

[0077] FIGS. 1-8 have already shown that the charge carrier entry causes small depressions shown in black in the figures, which increase in number with increasing charge carrier entry. At the same time, electrochemical roughening also has effects on other surface parameters of the aluminium alloy strip surface, which is facing the imaging coating of the printing plate.

[0078] Printing plate supports manufactured from the electrochemically roughened aluminium strips showed significant differences in terms of the mean contact area portion Smr (c=+0.25 μm) of the surface portions oriented in the rolling direction, as can be seen in Table 4. The printing plate supports according to the invention has significantly lower mean contact area portions Smr (c=+0.25 μm) of the surface portions oriented in the rolling direction, which decreased even further, in particular with very high charge carrier entry at 700 C/dm.sup.2 or 800 C/dm.sup.2. Similar behaviour was also shown in the comparison strips, albeit at a much higher level. Overall, the mean contact area portion Smr (c=+0.25 μm) of the surface portions oriented in the rolling direction are not reduced below the 4% limit by the electrochemical roughening of the comparison strips. The aluminium strips according to the invention also showed a ratio Rp/Rv of a maximum of 0.45, wherein most of the values were below 0.41. As expected there was a very low dependency on the charge carrier entry during electrochemical roughening. The comparison examples were significantly above these values. A value of 0.43 at 400 C/dm.sup.2 and 500 C/dm.sup.2 charge carrier entry could only be measured in comparative example f.

[0079] However, the printing plate supports according to the invention manufactured from the test strips a, b, c, d and m showed a ratio Rp/Rv of 0.40 to 0.34 from 600 C/dm.sup.2 and thus a significantly lower Rp/Rv ratio than in the comparison strips. The surface topographies of the printing plate supports according to the invention were thus designed to be even flatter than in the case of printing plate supports manufactured from the comparison strips. The examinations of the aspect ratio of the surface texture Str after electrochemical roughening showed significant differences. The aspect ratio Str is a measure of the isotropy of the roughened surface. The value Str reaches 100% when the surface is completely isotropic. While the printing plate supports a, b, c, d and m produced from test strips according to the invention can already provide an aspect ratio of the surface texture Str of at least 20% or at 500 C/dm.sup.2 of at least 50% at 400 C/dm.sup.2, the comparison strips only show an aspect ratio of the surface texture Str of at least 20% at 700 C/dm.sup.2.

[0080] It follows from this that the aluminium strips according to the invention can provide isotropically roughened surfaces with less charge support entry and can thus be processed more economically into printing plates. At the same time, the printing plates according to the invention also provide a longer service life for printing plates with very thin imaging coatings.

TABLE-US-00001 TABLE 1 Composition of the test strips in wt.-%, residual Al, unavoidable impurities individually max. 0.05 wt.-%, in total max. 0.15 wt.-%, arithmetic mean roughness Ra defined in DIN EN 10049 perpendicular to the rolling direction, state H18 with intermediate annealing, state H19 without intermediate annealing during cold rolling. Test Thickness Ra Composition in wt.-%, strips State [mm] [μm] Si Fe Cu Mn Mg Cr Zn Ti a Inv. H18 0.37 0.11 0.08 0.37 0.001 0.004 0.20 0.001 0.012 0.005 b Inv. H19 0.37 0.09 0.08 0.43 0.001 0.040 0.28 0.001 0.012 0.006 c Inv. H19 0.275 0.10 0.08 0.43 0.001 0.040 0.27 0.001 0.011 0.005 d Inv. H18 0.274 0.11 0.09 0.45 0.002 0.042 0.28 0.001 0.011 0.006 m Inv. H19 0.37 0.11 0.08 0.43 0.001 0.041 0.28 0.001 0.013 0.007 f Comp. H18 0.275 0.19 0.09 0.38 0.001 0.002 0.20 0.000 0.014 0.008 g Comp. H19 0.275 0.19 0.09 0.44 0.001 0.042 0.28 0.001 0.012 0.008 h Comp. H18 0.275 0.19 0.09 0.43 0.001 0.041 0.28 0.001 0.011 0.008

TABLE-US-00002 TABLE 2 Surface measurements of aluminium alloy strips after rolling, mean peak height Rp, mean peak number RPc defined in DIN EN ISO 4287 and DIN EN 10049 with calibrated optical roughness measurement system, Smr with calibrated optical Roughness measurement system defined in DIN EN ISO 25178. Smr Test Rp RPc c = +0.25 μm strips [μm] [cm.sub.-1] [%] a inv. 0.65 35.2 3.45 b inv. 0.65 12.9 2.00 c Inv. 0.69 9.4 1.73 d Inv. 0.73 20.5 2.78 m Inv. 0.74 34.3 3.78 f Comp. 0.88 68.4 8.09 g Comp. 1.32 92.3 11.47 h Comp. 1.06 74.4 9.32

TABLE-US-00003 TABLE 3 Mean peak height Rp defined in DIN EN ISO 4287 on the roughened printing plate support depending on the charge carrier entry for electrochemical roughening in HCl. Roughening in HCl - charge carrier entry [C/dm.sup.2] Not roughened 300 400 500 600 700 800 Test strips Rp [μm] a Inv. 0.65 0.73 0.77 0.95 0.95 1.01 1.03 b Inv. 0.65 0.65 0.78 0.76 0.82 0.88 0.93 c Inv. 0.69 0.71 0.74 0.86 0.86 0.90 0.97 d Inv. 0.73 — 0.80 0.86 0.92 1.01 1.01 m Inv. 0.74 0.75 0.79 0.86 0.89 0.92 1.06 f Comp. 0.88 0.89 1.09 1.08 1.19 1.25 1.26 g Comp. 1.32 1.36 1.37 1.41 1.41 1.49 1.49 h Comp. 1.06 1.06 1.14 1.23 1.33 1.29 1.32

TABLE-US-00004 TABLE 4 Contact area portion Smr at c = +0.25 μm in % in accordance with DIN EN ISO 25178 on roughened printing plate support depending on the charge carrier entry for electrochemical roughening in HCl. Roughening in HCl - charge carrier entry [C/dm.sup.2] Not roughened 300 400 500 600 700 800 Test strips Smr at c = +0.25 μm [%] a Inv. 3.45 2.52 2.32 2.87 2.15 2.02 1.43 b Inv. 2.00 1.36 0.73 0.74 0.60 0.63 0.34 c Inv. 1.73 1.99 1.68 1.70 1.18 0.77 0.66 d Inv. 2.78 — 1.87 1.57 1.55 1.56 0.86 m Inv. 3.78 2.70 2.25 1.92 1.81 1.10 1.20 f Comp. 8.09 8.06 7.67 6.51 6.37 5.81 4.16 g Comp. 11.47 10.22 11.14 9.96 8.52 8.57 6.07 h Comp. 9.32 8.88 8.67 8.08 7.63 6.69 4.88

TABLE-US-00005 TABLE 5 Ratio Rp/Rv in each case defined in DIN EN ISO 4287 on the roughened printing plate support depending on the charge carrier entry for electrochemical roughening in HCl. Roughening in HCl - charge carrier entry [C/dm.sup.2] Not Test roughened 300 400 500 600 700 800 strips Rp/Rv a Inv. 1.04 0.44 0.39 0.44 0.39 0.38 0.38 b Inv. 1.33 0.35 0.39 0.34 0.34 0.34 0.34 c Inv. 1.53 0.45 0.38 0.38 0.36 0.35 0.35 d Inv. 1.38 — 0.41 0.37 0.40 0.38 0.37 m Inv. 1.39 0.45 0.38 0.38 0.38 0.35 0.38 f Comp. 1.24 0.49 0.43 0.43 0.47 0.46 0.46 g Comp. 2.50 0.69 0.56 0.55 0.55 0.57 0.54 h Comp. 2.14 0.71 0.58 0.58 0.56 0.50 0.48

TABLE-US-00006 TABLE 6 Aspect ratio of the surface texture Str in accordance with DIN EN ISO 25178 on the roughened printing plate support depending on the charge carrier entry for electrochemical roughening in HCl. Roughening in HCl - charge carrier entry [C/dm.sup.2] Test Not roughened 300 400 500 700 strips Str [%] a Inv. 1.70 3.50 21.60 65.70 83.60 b Inv. 1.60 5.60 70.10 82.90 83.10 c Inv. 1.50 1.90 54.60 74.00 82.90 d Inv. 1.80 — 32.10 76.20 82.60 m Inv. 1.90 2.10 49.80 73.70 84.20 f Comp. 1.20 1.50 2.90 58.20 79.30 g Comp. 1.20 1.60 2.00 3.20 27.10 h Comp. 1.40 1.40 1.80 2.10 67.20

TABLE-US-00007 TABLE 7 Arithmetic mean roughness Ra of the roller surface in accordance with DIN ISO 4287. Degree of unrolling of last Test strips Ra [μm] cold rolling pass a Inv. 0.15 − 0.17 40 − 55 b Inv. 0.11 − 0.13 40 − 55 c Inv. 0.11 − 0.13 40 − 55 d Inv. 0.13 − 0.15 40 − 55 m Inv. 0.15 − 0.17 40 − 55 f Comp. 0.22 − 0.25 40 − 55 g Comp. 0.22 − 0.25 40 − 55 h Comp. 0.22 − 0.25 40 − 55