US 6,856,428 B1 · Black text printing from page description languages

Abstract

A technique for printing black text on a colored background, in which the graphics are broken down into three categories: text, polygons (also referred to as line drawing or vectors), and images (also referred to as bitmaps or raster data) when the incoming graphic information is a Page Description Language (PDL) data file (e.g. Adobe Postscript-PS- or Hewlett-Packard PCL). If the object is not a text object, it is processed in a normal manner. If the object is a text object, a determination is made if the color of the object is black. If the object is not a black text object, it is processed in a normal manner. If the object is a black text object, special processing and rasterization techniques are applied. Thus, the invention exploits to advantage the fact that it is possible in most PDL instances to treat black text differently from other black objects.

Claims26

Dependent claims

A method for compensating for color plane misregistration comprising the steps of:

providing a data file of incoming graphic information that includes a plurality of object categories, wherein one of said object categories is text objects;
determining if an object within said incoming graphic information is a text object, wherein if said object is not a text object it is processed in a normal manner;
if said object is a text object, determining color of said text object;
wherein, if said text object is not black, it is processed in a normal manner;
and
wherein, if said text object is black, applying selected processing to said object;
wherein said selected processing comprises a black text overprint mechanism;
whereby gaps resulting from misregistration are filled with a background color.

5 more elements

A method for printing black text on a colored background, comprising the steps of:

providing a data file of incoming graphic information that includes a plurality of object categories, wherein one of said object categories is text objects,
determining if an object within said incoming graphic information is a text object, wherein if said object is not a text object it is processed in a normal manner;
if said object is a text object, determining color of said text object;
wherein, if said text object is not black, it is processed in a normal manner;
and
wherein, if said text object is black, applying selected processing to said object;
wherein said wherein said selected processing comprises:
a black text overprint mechanism for a PCL language interpreter, in which each color is represented by three components:
c, m, and y;
in which each color is encoded on four bytes for convenience, where the k-byte is unused until a final conversion of cmy to cmyk, immediately before physical printing;
and
in which the expression c,m,y,k(b) is a cmyk value of a background 5 immediately before text is to be rendered;
the expression c,m,y,k(d) is a color that results from combining a source with a background according to a predefined function F;
and the expression c,m,y,k(t) is a cmyk value of a temporary color;
wherein:
c,m,y(d)=F(c,m,y(s);c,m,y(b))
if said black text overprint mechanism is disabled;
and wherein:
if (object to be rendered is text and color is black:
c=m=y=255)
{
if (background color is not white-either c or m or y is not 0)
{
c,m,y,k(t) = c,m,y,k(b)
if(k(b) = 255)
c,m,y,k(b) = 255,255,255,0
c,m,y,k(d) = F(black text(source),c,m,y,k(b))
if (destination is process black)
c,m,y,k(d) = c,m,y(t),255
}
else
{
c,m,y,k(d) = F(black text(source),c,m,y,k(b))
}
}
if said black text overprint mechanism is enabled.

33 more elements

An apparatus for printing black text on a colored background from a data file of incoming graphic information that includes a plurality of object categories, wherein one of said object categories is text objects, comprising:

means for determining if an object within said incoming graphic information is a text object, wherein if said object is not a text object it is processed in a normal manner;
if said object is a text object, means for determining color of said text object;
wherein if said text object is not a black text object, it is processed in a normal manner;
and
means for applying selected processing to said object if said object is a black text object;
wherein said selected processing comprises:
a black text overprint mechanism for a PCL language interpreter, in which each color is represented by three components:
c, m, and y;
in which each color is encoded on four bytes for convenience, where the k-byte is unused until a final conversion of cmy to cmyk, immediately before physical printing;
and
in which the expression c,m,y,k(b) is a cmyk value of a background immediately before text is to be rendered;
the expression c,m,y,k(d) is a color that results from combining a source with a background according to a predefined function F;
and the expression c,m,y,k(t) is a cmyk value of a temporary color;
wherein:
c,m,y(d)=F(c,m,y(s);c,m,y(b))
if said black text overprint mechanism is disabled;
and wherein:
if (object to be rendered is text and color is black:
c=m=y=255)
{
if (background color is not white-either c or m or y is not 0)
{
c,m,y,k(t) = c,m,y,k(b)
if(k(b) = 255)
c,m,y,k(b) = 255,255,255,0
c,m,y,k(d) = F(black text(source),c,m,y,k(b))
if (destination is process black)
c,m,y,k(d) = c,m,y(t),255
}
else
{
c,m,y,k(d) = F(black text(source),c,m,y,k(b))
}
}
if said black text overprint mechanism is enabled.

32 more elements

Dependencies are inferred from the claim text.

Black text printing from page description languages

Life of this patent

Black text printing from page description languages

Life of this patent

Abstract

Claims26