CN1348846A - Method for producing gravure cutting data - Google Patents

Abstract

The present invention relates to method of producing gravure carving data, based on the geomtric shape of element contained in printed original manuscript, and within predetermined change range of gravure carving data, select at least one working lattice different from said preset lattice. At first, we select at least one line element in said printed original manuscript, and find out a working lattice within said change range, said lattice is matched in density and/or angle with the selected line element in repeatability. The we select script element in said printed original manuscript, said element and said working lattice are matched with the help of script font-hinting data.

Description

Produce the method for gravure cutting data

The present invention relates to a kind of method that produces gravure cutting data, be used in particular for photogravure roller based on vector printed original and default grid.The invention still further relates to the device that a kind of gravure cutting data that uses described method to produce is carved photogravure roller.

Electronic mechanical forme engraving method has promptly reached higher precision and reliability as far back as the seventies.(for example referring to European patent document EP 0056829 B1) must mate mutually to the grid of the different colours in the four-color process in known method, to avoid producing visible color shift (aberration).

According to known method, when from printed original, producing gravure cutting data (promptly controlling the data that engraving machine is processed photogravure roller) with the digital form storage, at first need generate a high resolution bitmap, be reduced to the mesh-density of printed matter trustee defined subsequently again.

Obviously, when described high resolution bitmap is transformed into the mesh-density of regulation, must accept to occur the consequence of accuracy of repetition loss.This causes occurring trickle line style and font fuzzy or uneven phenomenon, i.e. Moire effect (Moire-Effektes) through regular meeting in practice.In the polychrome printing product, unnecessary colour cast phenomenon can appear on the lines border, owing to used different color grids, so can't avoid the different lines border of corresponding appearance.

Task of the present invention is, a kind of method of the above-mentioned type is provided, and it can realize the highest graphical quality (" sharply distinct ", " color is accurate ") according to meticulous printed original.

The solution of above task is embodied in the characteristic of claim 1.The present invention does not adopt the printing density (mesh-density) of (printed matter the trustee expect or require) regulation simply, but define an excursion around the printing density of defined, and in this scope, obtain a kind of grid with optimum Match according to the geometry that is present in the element in the concrete printed original.

Principle of the present invention is, in the excursion of described (in advance) definition, not to select the meticulousst grid simply, but according to dissimilar (for example repeatability of a bargraphs) of geometry, can combine with described geometry (for example repeated) by adopting sparse slightly grid fully, thereby obtain having the figure of utmost sharpness.Wherein importantly, engraving machine can produce arbitrarily grid (for example 70.65 or 63.88) in principle, and is not only to accept discontinuous tabular value (for example 65,70,90).It is further noted that, adopt the method for the invention, the primary data that does not have resolution limit is had best result of use, in the case, can save high resolution bitmap fully.

Described excursion is a parameter of suitably selecting of the method for the invention.This scope is no more than 1/3 of regulation grid resolution usually, for example can be 20% or littler.It does not need symmetry (for example+/-10%) with respect to the grid numerical value of regulation, but the number range (for example default grid+12%/-8%) of some skews can be arranged.

In first step, can measure the lines element (can adopt simple relatively look-up command to realize) in the printed original according to vector data.For this lines element, can in described excursion, determine a what is called work grid that is complementary with lines geometry (for example width, spacing and/repeatability).According to different results, described work grid can directly use as the engraving grid, perhaps continues to change or revise.The purpose of mating is that site (grid cell) and lines (element) border are sheltered.

Font elements to printed original in next procedure is discerned, and based on the described work grid of existing font hinting Data Matching.That is to say that described font elements (letter with regulation font) moves, extends or tightens, thereby level and vertical fragmentation are sheltered with described work grid in by the defined scope of font hinting data.

In known polychrome printing, be to adopt predetermined grid group operation.If grid mates according to the element of described method step according to printed original for certain color, then therefrom will produce the work grid (for example referring to European patent document EP0056829) of other colors.According to basic thought of the present invention, the work grid of other colors also should be complementary with lines element and font elements.Generally speaking, there is not this situation.So for this reason, the grid of other colors is according to the element of described method and printed original coupling.Situation about can not get rid of is, though can find the grid of optimum Match to a kind of color, but other affiliated color grids but can not obtain enough (promptly in allowing boundary) to be extended, tighten, zooms in or out, thereby obtains receptible on the whole effect.Therefore in order to improve whole structure, perhaps need the color grid of described " optimum Match " is only selected " accurate best ", make other color grids obtain desired matching precision, perhaps return printed original (allowing the graphics process personnel make amendment).

For further improving printing effect, described work grid and live part (for example each brand logo) can be complementary.Also adopt herein and extend or tighten grid geometry work.

Can also be defined at last between each live part, photogravure roller axially on (equaling the direction of feed of engraving member) move small distance." small " distance should be understood to the scope that also should be positioned at above-mentioned grid variation zone less than this distance of spacing between the site.Can guarantee that in this way live part not only has identical quality substantially, and is on all four.That is to say that in each live part, the residual defect of appearance accurately is positioned at identical position, and masked with the same manner.

Within the scope of the invention, can also between different grids, change direction of feed.The meaning of this measure for example is, if when the diverse live part of engraving on the cylinder (for example different trade mark of printing on a bottle), also can be best each live part be realized the printing quality that be complementary.

The input data can be unique data blocks (file) or be divided into different parts.In first kind of situation, engraving adopts no interrupt mode once to finish.In second kind of situation, engraving member can (perhaps must) be done stop of short duration between each data block, so that the grid that changes is set the control parameter.

The method of the invention itself has nothing to do with using which kind of engraving technology.But it is mainly used in the engraving machine (latter has the graver of a vibration) that adopts laser technology and the work of electronic mechanical principle.The formation and the control mode of this engraving machine are that ranks spacing on its direction of feed and point are can be freely regulated apart from (being the grid cell spacing) in inside, unit.

Other advantageous embodiments of the present invention and feature combination in following detailed description and all authority requirement, have been provided.

Employed accompanying drawing is as follows in the explanation of embodiment:

Fig. 1 a, b represent PDL (Post Script) data are carried out the problem definition schematic diagram of grid when handling;

Fig. 2 represents principle schematic of the present invention;

Fig. 3 represents the vertical view of grid cell structure;

Fig. 4 represents that a cylinder surface is divided into the example of different live parts and segmentation;

Fig. 5 represents a pending grid graph example.

Embodiments of the invention

Existing problem during the concise and to the point shown grid of Fig. 1 a and Fig. 1 b is set.(referring to Fig. 1 is a kind of font that adopts the PDL form (in the following description, the synonym of the description of resolution limit is described or do not had to the notion of " PDL " any vector quantization of should be understood to font, lines or other graphical formats) a) to starting point in this example.If, then almost will inevitably produce blooming, because grid does not have or can not be complementary with font elements with a kind of like this font of a kind of desired grid (shown in the represented grid graph of Fig. 1 a) printing.(for example in the gravure process) for example produces the printing effect shown in Fig. 1 b in a kind of halftoning printing process.In the polychrome printing this problem of should be noted in the discussion above that can appear on each color in four looks, and its form of expression has nothing in common with each other.For recurrent lines element, the influence of this problem is especially serious.

Fig. 2 has described the principle of the method for the invention.What suppose printed original 1 employing is PDL form (this form for example generates by a kind of suitable procedure in computer, and can be used as the file use).Contain different font elements 1.1 (being arranged in prospect among the figure) in the described printed original 1, and lines element 1.2 (being arranged in background).Also has the printed matter trustee in addition, for example a grid group 2 (4 different color grids 2.1 to 2.4 are arranged in the present embodiment, be used for 4 kinds of printing-inks) of graphics process person's regulation.

According to the present invention, determine work grid group 4 (described in practice grid computing device 3 is software or software module) with printed original 1 optimum Match by a grid computing device 3.Described work grid group 4 departs to some extent with the printing density and/or the angle of grid group 2.But this departs from and is in the predefined excursion, for example+/-10% (size of excursion is decided with concrete condition, its on the one hand and the printed pattern with 2 generations of predetermined cell group must not compare and reduce quality, must not produce the unnecessary meticulous degree of depth on the other hand.This scope also character with employed printing-ink is relevant, and is relevant with factors such as carrier material and grid fineness).Described work grid under normal circumstances is not equal to common grid (for example ° oblique angle, every centimetre 70 line/40).It can get numerical value (for example ° oblique angle, every centimetre 73.453 line/38.120) arbitrarily.Described work grid can be determined by the relevant lines element of analyzing printed original 1 automatically in principle.For example if there is flagpole pattern, the frequency of the grid 4 of then working will be complementary with the frequency of flagpole pattern, and making the spacing of lines and width need not part " swing " (fluctuation) can reproduce.Can introduce so-called stroke prompting (Stroke-Hinting) information this moment.From this information, can learn, in which kind of boundary and according to which kind of rule, allow spacing and width are changed.

Then calculate (what should spell out is, described gravure cutting data calculator 5 is the same with above-mentioned grid computing device 3, can be one of integration module of a software kit) herein by 5 pairs of described gravure cutting datas 6 of a gravure cutting data calculator.In this process range, described font elements can utilize corresponding font hinting (Font-Hinting) information (corresponding with font) to aim at described work grid group 4 in the case of necessary.

At last, described gravure cutting data 6 is transferred to a mechanical engraving machine 7, is used to make photogravure roller 8.Obviously, must guarantee on the structure principle of described engraving machine 7 to carve with grid arbitrarily.In other words, the feeding of angular speed of photogravure roller 8 (the perhaps operating frequency of graver) and engraving member step widely must be carried out the high accuracy adjusting with any number.

What Fig. 3 represented is a typical structure example of grid cell 9.1 to 9.13, the situation that it for example is equivalent to a mechanical engraving machine when carrying out sculpting operation on the photogravure roller surface.Used following parameter (x=is axial, and u=is circumferential) in the example below:

The centre-to-centre spacing of the grid cell between two engraving row of wx=

The centre-to-centre spacing of the grid cell between two engraving row of wu=

Two of dx=side by side the spacing of grid cell in same engraving is capable

Fig. 4 represents that a photogravure roller surface is divided into different graphic, the example of the promptly different live parts trade mark of different size (as have);

N1=treats engraving pattern (live part) in dimension of picture 1

N2=treats engraving pattern (live part) in dimension of picture 2

Suppose that each live part N1.i is identical with N2.i (i=1-6):

N1.1＝N1.2＝N1.3＝N1.4＝N1.5＝N1.6

N2.1＝N2.2＝N2.3＝N2.4＝N2.5＝N2.6

Used following naming system in addition:

N1x, the width of N2x=live part:

N1x_mm, N2x_mm=are the width of the live part of unit mensuration with mm;

The N1x_ unit, N2x_ unit=with the number of spacing wx is the width of the live part measured of unit;

N1u, the height of N2u=live part:

N1x_mm, N2x_mm=are the height of the live part of unit mensuration with mm;

The N1x_ unit, N2x_ unit=with the number of spacing wu is the height of the live part measured of unit;

The width of X=cylinder:

X_mm=is the width of the cylinder of unit mensuration with mm;

X_ unit=with the number of spacing wx is the width of the cylinder measured of unit;

The girth of U=cylinder:

U_mm=is the girth of the cylinder of unit mensuration with mm;

U_ unit=with the number of spacing wu is the cylinder girth that unit measures;

X1=cylinder segmentation 1

X2=cylinder segmentation 2

Grid circulation among Fx (Ni)=in the axial direction live part Ni, unit: mm

The grid circulation of Fu (Ni)=in the live part Ni that makes progress in week, unit: mm

Fx1, the chrominance component of fu1=patterned grid

Fx2, the white color component of fu2=patterned grid

The task of the explanation institute foundation of following examples is: live part N1 and N2 are carved respectively six times with the highest graphical quality.Live part N2 wherein with 2/3 ratio less than live part N1.Also stipulated a grid group as shown in Figure 2, the final effect of described work grid group should be similar to the effect of this grid group.Therefore two centre-to-centre spacing wx and wu that carve between row or the engraving row have been provided.

Lattice structure (lines element) is as shown in Figure 5 for example arranged in printed original.Owing to have the live part N1 and the N2 of different sizes, so can obtain four kinds of structural change repetitive rate Fx (N1), Fu (N1), Fx (N2), Fu (N2) altogether from concrete lattice structure geometry, the border that structure repeats to change must be sheltered with described work grid.

Say that in principle the greatest common factor (G.C.F.) ggT between repetitive rate Fx of described structure (N1) and Fu (N1) and Fx (N2) and the Fu (N2) (english abbreviation is the gcd=greatest common factor (G.C.F.)) is determined.Because (because two live parts have different sizes and be not easy mutual coupling with regard to its sizes) in the present embodiment, being used to regulate the spacing wx of best effort grid circulation and the modification of wu is very restricted, so according to a preferred embodiment, at first cylinder surface is divided into two segmentation x1 and x2 (data block), because on this segmentation is positioned at axially, so can adopt different work grids to carve.These two (being respectively homogeneous) segmentation x1 itself and x2 can separately fully handle (and similar mutually).So segmentation x1 is only quoted in following explanation.

In next procedure, must (wx wu) compares with the network of a greatest common factor (G.C.F.) ggT and a live part (as N1.1).If this greatest common factor (G.C.F.) ggT is consistent with network or the latter's integral multiple, but end process process then, and need not to change wx and wu.But this situation can not appear usually, so to spacing wx and the necessary change of wu, make that greatest common factor (G.C.F.) ggT and the spacing wu on u direction is masked on the one hand, on the other hand in greatest common factor (G.C.F.) on the x direction and wx masked (on the meaning at module operation) promptly until reaching an integral multiple.(for example, if Fu=0.5mm and wu=0.11mm then must change spacing wu, just to obtain four sites or just obtain five sites on circulation Fu.) as boundary condition, what should consider is that this change can only change in specific boundary (excursion), so that realize the similitude of desired and default grid subsequently.If described numerical value can reach coupling, then can finish described process, that is to say that wu and wx mate (this in practice coupling is very little) according to desired size.

If can not reach coupling, then to select to have the more frequency overlap of high duplication, thereby reduce not Lay effect and fluctuation.Result as this process is new wu and a wx value of output.

The size N1x_mm of available live part and N1u_mm are divided by new spacing wu and the wx that measures at this moment.Thereby can obtain size N1x_ unit, N1u_ unit (can produce grid pattern on its basis).If since with mm be unit size can not with integer by spacing wu and wx except, and produced a mark of the spacing of grid cell, then can be compensated by height or the width that changes grid cell subsequently.

Described recess engraving data calculator is at first put other graphic elements of live part in order according to the work grid that is calculated.Wherein use known (developing) " font hinting " and " stroke prompting " method by Adobe company.

If what relate to is that a kind of single color printing production or described network are not used in the common ink printing, but is used for the special ink printing, then can carries out gridding to whole printed original this moment and handle.Otherwise need calculate the coupling of all relevant colors grids, and carry out mutual balance where necessary (being that all colours grid must mate).If being used for the method step of all colours grid is identical in principle, then repeat no more.

Because in example shown in Figure 4, not only in the axial direction, and upwards some live parts are carved, so the coupling of the above spacing wx and wu may cause occurring undesirable " defect propagation " (adding up) in week.This defective can be compensated by remodifying spacing wx and wu.In this case, do not need to carry out again gridding certainly, only need be to the shape of grid cell (small rut) make amendment (extension/deflation).

For the problem of unlikely generation grid combination erroneous matching between different colors, equally also can revise spacing dx.To insert very little correction spacing (roughly less than 1-2%) this moment.

Though this step can change the metric size in the figure, the change in size that in press takes place after being significantly smaller than is for example because paper shrinks the variation that takes place.

Engraving machine obtains following information at this moment: have the grid file of cylinder segmentation x1 of affiliated spacing wu and wx and the correction value of being measured; Have the grid file of cylinder segmentation x2 of affiliated spacing wu and wx and the correction value of being measured.

The present invention can adopt multiple mode to be changed.Can insert correction value in any stage in principle, both not only under the situation of coupling lines and font elements, and under the situation of the quantity of the size of having considered live part on the cylinder surface and live part and structure, carry out.For example a kind of favourable scheme is that the live part that needs punching press is subsequently carried out small coupling (for example by inserting an additional feeding step) in punch line.Do not require through all described stages all the time in addition yet.

In sum, identifiable be by the invention new may, particularly the machine-building by photogravure roller can provide high-quality print product.This technology can adopt the mode of full-automatic or manual intervention to carry out.

Claims (10)

1. produce the method for gravure cutting data (6), be used in particular for photogravure roller based on vector printed original (1) and default grid (2), feature of the present invention is, geometry according to the element that comprises in the printed original, in a predefine excursion of gravure cutting data (6), select at least a work grid (4) that is different from described default grid (2).

2. the method for claim 1, it is characterized in that, at first select at least one lines element in described printed original (1), and obtain a kind of work grid in described excursion, this grid is being complementary with the repeatability of the lines element selected aspect density and/or the angle.

3. method as claimed in claim 2 is characterized in that, described work grid considers that additionally stroke prompting (Stroke-Hinting) data mate.

4. as claim 2 or 3 described methods, it is characterized in that select font elements in described printed original (1), this element and described work grid mate by font hinting (Font-Hinting) data.

5. as the described method of any one claim in the claim 1 to 4, it is characterized in that, the geometry of grid on line direction and/or direction of feed that belongs to the different colours printing-ink extended or tightened, thereby aim at selected lines element.

6. as the described method of any one claim in the claim 1 to 5, it is characterized in that, from described printed original (1), select at least two live parts, and described work grid is by extra extension or the described live part of deflation coupling.

7. method as claimed in claim 6 is characterized in that, described gravure cutting data (6) mates according to a size of photogravure roller, and its mode is the extra feeding step of inserting between each live part.

8. as the described method of any one claim in the claim 1 to 7, it is characterized in that the gravure cutting data that is used for described photogravure roller is divided into the segmentation with different operating grid on direction of feed.

9. as the described method of any one claim in the claim 1 to 8, it is characterized in that described excursion is print thickness and/or angle≤1/3, particularly≤1/5.

10. use the gravure cutting data of method generation according to claim 1, the device that photogravure roller is carved, it is characterized in that, have in the axial direction one can the freely regulated amount of feeding, on line direction, have one can freely regulated grid cell at interval.

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