MXPA97002843A - Printing method to avoid bleeding between colo - Google Patents

Abstract

The present invention relates to a printing method using an ink jet printer that injects a first color ink and a second color ink onto a printing medium at places defined by an image area having a plurality of pixels, said method inhibiting bleeding between colors between the first color ink and the second color ink, said method comprising the steps of: selecting a first series of pixels in the image area, said first series comprising a series M x N, where M and N integers, define a portion of the first series as a second series of pixels, said second series comprising a series X x Y, where X and Y are integers, said integers X and Y being smaller than said integers M and N, respectively , and at least one of said integers X x Y being greater than 1, examining said pixels within said second series, and altering said pixels within said first series if said pixels examined within said second series substantially all correspond to the first ink of cabbage

Description

PRINTING METHOD FOR AVOIDING BLEEDING BETWEEN COLORS BACKGROUND OF THE INVENTION 1. Field of Invention. The present invention relates to inkjet printers, and, more particularly, to a method for preventing bleeding between colors when using multi-color inkjet printers. 2. Description of the Related Art. Typically, an inkjet printer. of multiple colors includes the structure for selectively injecting an indelible blue, yellow, magenta and / or black ink onto a printing medium such as paper. To provide an improved overall print quality, it is known to use an indelible, pigmented, high surface tension black ink and a blue, yellow and magenta penetrating color ink. The indelible, pigmented black ink of high surface tension tends to penetrate slowly into the paper, resulting in higher optical density of solid black areas, less branching (or dew) of the indelible black ink, and fewer satellites (caused by the breaking of the ink droplet during the flight). Penetrating blue, yellow and magenta inks penetrate more quickly into paper and are used to prevent intercolor bleed between inks of various colors.

A problem that sometimes arises when using a black, pigmented, indeterminable ink of greater surface tension and a penetrating blue, yellow and / or magenta ink is that when such inks are injected onto the paper, the indelible black ink stain, of Higher surface tension and the blue, yellow and / or magenta ink spot of lower surface tension tend to mix. It is believed by the present inventors that a slower drying of the indelible black ink spot, when it is still wet, mixes slightly with the penetrating agents present in the blue, yellow and / or magenta ink stains, which causes The indelible black ink stain placed near the spot of blue, yellow and / or magenta ink penetrates the paper as well. This mixing is most pronounced when printing a solid black area near an area of blue, yellow and / or magenta ink, which causes a visually objectionable print artifact. A known method for inhibiting bleeding between colors is the separate examination of each singular pixel in an image area to determine whether the individual pixel is a black pixel that lies adjacent to a color pixel. If the singular, examined pixel lies adjacent to a color pixel, then a black ink spot (black CYM) of faster drying process is replaced by an indelible black ink spot. Alternatively, if the singular, examined pixel corresponds to a black ink spot on the edge of a substantial black area, then a row of colored spots immediately adjacent to the black area can be removed. It is also known to divide a plurality of pixels that form an image area into a plurality of 2 x 2 cell series. Drops of blue, yellow and / or magenta ink are deposited only on a pair of diagonally adjacent cells, with no more than two drops of ink per cell and no more than three drops of ink per series of 2 x 2. In this way , in essence, the pixels of the image area are printed in a "board" manner that reduces the bleed between colors. What is needed in the matter is an improved method that uses a multi-color inkjet printer that reduces or inhibits intercolor bleed between inks of different colors. SUMMARY OF THE INVENTION The present invention provides a printing method that inhibits bleeding between colors, wherein a portion of an image area is divided into a smaller series of pixels placed within a larger series of pixels. If all the pixels within the smallest series are determined as indelible black pixels, the remaining color pixels within the larger series are altered, such as by removing a portion of the available color pixels within the larger series. The invention comprises, in one form thereof, a printing method using an ink jet printer that injects a first color ink and a second color ink onto a printing medium at locations defined by an image area that it has a plurality of pixels. The method inhibits bleeding between colors between the first color ink and the second color ink. A first series of pixels is selected in the image area, the first series being a series of M x N where M and N are integers. A portion of the first series is defined as a second series of pixels, the second series being a series X x Y where X and Y are integers. The integers X and Y are smaller than the integers M and N, respectively. The pixels within the second series are examined. The pixels within the first series are altered if the pixels examined within the second series substantially correspond to the first color ink. An advantage of the present invention is that bleeding between colors is inhibited. BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned features and advantages of this invention, and the manner of obtaining them, will become more apparent and the invention will be better understood with reference to the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. , wherein: Figures 1A, IB and 1C are graphic illustrations showing the alteration of pixels in a portion of an image area by the use of a method of the present invention to inhibit bleeding between colors; Figures 2A, 2B and 2C are graphic illustrations showing a different alteration of the pixels in a portion of an image area by using a method of the present invention to inhibit bleeding between colors; Fig. 3 is a flow diagram illustrating one embodiment of the overall logic of the printing method of the present invention; and Figure 4 is a flow chart illustrating a mode of the logic used to examine the image area of the printing medium on which the ink is injected. The corresponding reference characters indicate corresponding parts through all the various views. The exemplifications set forth herein illustrate a preferred embodiment of the invention, in one form, and such exemplifications are not construed as limiting the scope of the invention in any way. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, and more particularly to Figures 1 and 2, respective graphic illustrations representing the alteration of the pixels in a portion of an image area using a method of the present invention are shown for inhibit bleeding between colors. The method is employed when using an inkjet printer that injects a first color ink (such as an indelible black ink) and a second color ink (such as a blue, yellow or magenta ink) onto a printing medium in places defined by an image area having a plurality of pixels. The image area can be represented by a bitmap stored in a memory. In this way, it is possible to associate a plurality of bits in the bitmap with a plurality of corresponding pixels that represent image data for the various colored inks that are injected onto the printing medium. The method of the present invention inhibits the intercolor bleed between the first color ink and the second color ink in a manner described below.

Figures 1A-1C and Figures 2A-2C show alternative graphic representations of pixels, which can be altered by using the method of the present invention. With each of the graphic illustrations shown in Figures 1-C and Figures 2A-2C, the image area represented by the bitmap stored in the memory is selectively divided into a plurality of series of pixels, the series being of uniform size. For example, in the embodiment shown in Figures 1A-1C and Figures 2A-2C, the image area is divided into a plurality of 6 x 6 series that overlap each other, as will be described below. For ease of exposure, the reference numbers 1-6 have been placed along the upper left side of the series shown in Figures 1A-1C and 2A-2C. In this way, the pixel in the upper left corner of each series is placed in position 1.1. A first or super series of pixels in the image area is defined by pixels 1.1 to 6.6. The first series has an amplitude dimension M and a height dimension N as shown in Figures 1C and 2C, the values of M and N being integers. In the particular embodiment shown, the integer values M and N are each equal to 6; however, other integer values are also possible for the variables M and N. The integer values M and N are preferably between 3 and 10, and more preferably are both equal to the integer value 6. In addition, the integer values M and N can be equal or different from each other, in such a way that the first series of pixels is square or rectangular. The first series is represented in the bitmap as image data associated with pixels 1.1 to 6.6. The image data represent color spots to be printed on the printing medium such as indelible black (K), yellow (Y), magenta (M), and blue (C). The blue, yellow and magenta stains can be placed adjacent to the indelible black spots (K) and thus result in bleeding between colors. To inhibit bleeding between colors, a second series of pixels is defined within a portion of the first series of pixels. In the embodiment shown, the second series of pixels is a series of 2 x 2 which is centrally located within the first series of pixels. The second series of pixels is thus placed in places 3.3; 3,4; 4.3; and 4.4. The second series of pixels also has the dimensions X and Y (Figures 1C and 2C), where X and Y are integers. The integers X and Y are smaller than the integers M and N, respectively, and are equal to 2 in the modality shown. It will be appreciated that the variables X and Y may be the same or different from each other, such that the second series of pixels may be square or rectangular. The pixels within X x Y or second series of pixels are examined to determine whether the image data corresponding thereto correspond to the first color ink (e.g., the indelible black ink). If substantially all the pixels within the second series correspond to the first color ink, then the pixels within the first series, exclusive of the pixels within the second series, are altered in a particular way. Alternatively, the pixels within the first series, exclusive of the pixels within the second series, may be altered if a certain percentage of the pixels examined within the second series correspond to the first color ink. For example, depending on the particular application and / or the selected sizes of the first and second series of pixels, the pixels within the first series may be altered if at least about 50%, 75%, or 90% of the pixels examined within the second series correspond to the first color ink. Referring to figure IB, a method is shown to alter the pixels within the first series, exclusive of the pixels within the second series. In this mode, the pixels of the second series (ie 3.3 pixel locations); 3,4; 4.3; and 4.4) correspond to indelible black ink spots (K) which are injected onto the printing medium. Since all the pixels of the second series correspond to the indelible black ink, the remaining pixels of the first series are altered by removing the selected pixels from the remaining pixels of the first series as pixels available for printing. The reference letter "R" indicates those pixels that have been removed as pixels available for printing. For ease of viewing and discussion, the remaining pixels of the first series have not been labeled with the corresponding ink colors (for example, in pixel places 1,2 and 1,4). As it is apparent, the pixels that are removed as pixels available for printing form a "board" pattern around the second series of pixels. Referring now to Figure 1C, there is shown a graphic illustration of the pixels corresponding to the color spots that are actually printed on the printing medium after the pixel alteration is carried out according to the illustration of figure IB . The blue, yellow and magenta spots are injected onto the printing medium in a board manner that is complementary to the removed pixels shown in Figure IB. Some of the blue, yellow and magenta spots are placed immediately adjacent to the indelible black ink spots within the second series of pixels. However, it has been found that although some of the spots may lie immediately adjacent to the indelible black area within the second series, the bleeding between colors is inhibited by the reduction in the number of remaining color spots within the first series. Referring now to Figure 2B, another method is shown for altering the pixels within the first series, exclusive of the pixels within the second series. The removed pixels are labeled "R", and the remaining pixels within the first series of pixels are not labeled for ease of discussion and visualization. In the embodiment shown in Figure 2B, all the pixels within the second series of pixels correspond to the indelible black ink spots (K). The pixels within the first series, exclusive of the pixels within the second series, are altered by removing all the pixels within the first series that are placed adjacent to the second series, as indicated by the pixels marked with the letter of reference "R". This provides a zone of separation between the indelible black ink spots within the second series and the blue, yellow, and magenta spots within the first series, and thereby inhibits bleeding between colors. Referring now to Figure 2C, a graphic representation of the pixels corresponding to the ink spots that are actually printed on the printing medium are shown after some of the pixels within the first series are removed as shown in the figure 2B. The pixels placed immediately adjacent to the indelible black pixels (K) of the second series do not contain image data therein, and therefore no blue, yellow, or magenta ink is deposited at the corresponding places on the printing medium. This zone of separation between the indelible black pixels of the second series and the color pixels printed within the first series inhibits a bleed between colors. As can be seen in Figure 1C, the indelible black pixels that are placed within the first series of pixels, but outside the second series of pixels (e.g., pixel location 6,6), need not be altered. That is, the bleed between colors does not occur between the indelible black pixels placed within the second series nor any of the remaining indelible black pixels placed within the first series. According to the above, such indelible black pixels remaining within the first series do not need to be removed as available pixels for printing. Another aspect of the present invention is that the remaining pixels within the first series may not be altered if the number of blue spots, yellow or magenta is determined to be such that bleeding between colors is not likely to result. That is, after the pixels of the second series are examined as to whether or not the image data in them corresponds to substantially all of the indelible black pixels, a determination can be made as to whether a predetermined percentage of the remaining pixels within of the first series corresponds to blue, yellow and / or magenta ink. If the percentage of the remaining pixels within the first series, exclusive of the pixels within the second series, does not correspond to the blue, yellow or magenta ink spots, the amount of colored ink spots that are injected onto the medium of Printing around the second series of ink spots may not be of sufficient magnitude to result in bleeding between colors. According to the above it may not be necessary to remove the available pixels for printing within the remaining pixels of the first series, as shown in Figures IB and 2B. In the modes shown, the remaining pixels within the first series are not altered unless approximately 50% of the remaining pixels within the first series correspond to blue, yellow or magenta ink spots.

However, it will be appreciated that the remaining pixels within the first series may not be altered unless a different percentage of pixels corresponds to blue, yellow or magenta ink spots, such as 70% or 80%. With respect to the graphic illustrations shown in Figures 1A-1C and 2A-2C, it may also be desirable for certain applications to alter the pixels within the first series, exclusive of the pixels within the second series, depending on the particular color of the the pixels within the first series. For example, if the pixels within the first series, exclusive of the pixels within the second series, correspond basically to blue or magenta ink spots that are to be injected onto the printing medium, it may be desirable to alter the pixels within the first series using the depletion board manner as shown in Figures 1A-1C. Alternatively, if the pixels within the first series, exclusive of the pixels within the second series, correspond basically to yellow ink spots that are to be injected onto the printing medium, it may be desirable to alter the pixels within the first series as shown in Figures 2A-2C in such a manner that the pixels adjacent to the second smaller series are exhausted. Referring now to Figure 3, there is shown a flow diagram illustrating one embodiment of the overall logic of the printing method of the present invention. First, a series of pixels M x N is selected within the image area (block 20). In essence, this consists of superimposing a series of predetermined dimensions M x N on the bitmap stored within the memory having image data stored therein, corresponding to the various color inks that are to be applied on the medium of Print. A series of X x Y is defined within each series M x N, as described above with reference to figures 1 and 2 (block 22). The X x Y series can be located centrally within the M x N series, but it can also be placed in the M x N series in another way. For the particular series of pixels within the selected M x N image area , a variable "Z" is assigned to it. The variable Z thus represents the position of the series M x N within the image area. In block 24, the Z value is set to 1 for the first selected series. In block 26, the selected particular series M x N, designated by the variable Z, is examined. This consists in the examination of the pixels within the series X x Y (or second series) in the series M x N (Z = 1) to determine if all the pixels in it correspond to indelible black image data (decision block 28). If the result is NO (line 30), a decision is made as to whether a particular Z series is being examined in the last series within the image area (decision block 32). If the series is the last to be examined within the image area (line 34), then the method ends at 36. On the other hand, if the series examined is not the last series to be examined (line 38), then the value of Z it is examined in block 26. The new series Z corresponds to a series representing a set of different associated pixels within the image area of the bitmap. Since the series M x N moves to a new place within the bitmap, the series X x Y also moves to the new place within the map. The M x N series and the X x Y series each retain their relative dimensions as they move from one place to another in the bitmap. In addition, the X x Y series is placed in the same relative location within the M x N series. If the pixels within the X x Y series are examined and all are found as indelible black pixels (line 42), then it is taken a decision of whether a predetermined percentage within the Z series and outside the X x Y series are blue, yellow and / or magenta pixels (decision block 44). If there is a percentage of pixels smaller than the default (for example 50%) within the remaining pixels of the Z series (line 46), then control passes to decision block 32 as described above. On the other hand, if there is a percentage of pixels blue, yellow or magenta greater than the default within the remaining pixels of the Z series (line 48), then the blue, yellow and / or magenta pixels within the Z series and outside of the the series X x Y are altered as described above with reference to either of the figures IB or 2B (block 50). After the color pixels within the Z series have been altered, the control passes through the line 52 to the decision block 32, as described above. Fig. 4 is a flow diagram illustrating a mode of the logic used to examine the image area of the printing medium on which the ink is injected. The image area is represented by a bitmap in a memory having corresponding image data therein. First, a series X x Y is defined within each series M x N as described above. The series M x N and the series X x Y can be rectangular or square. In addition, the series X x Y can be located centrally, or located in a different way to the central one, within the series M x N (block 60). With reference to the following description, it should be understood that the series X x Y maintains its position within and in relation to the series M x N major. After the series X x Y is - II defines within the series M x N, the series X x Y is placed in the upper left corner of the image area (block 62). Thus, in relation to the series shown in Figure 1A, the two upper rows and the two left columns are placed essentially outside the bitmap at this point in time. The series X x Y is then examined for all indelible black pixels (block 64). In block 66, the blue, yellow, and magenta spots that are placed within the M x N series and outside the X x Y series are altered if appropriate (such as when determining if a predetermined percentage of the pixels placed outside of the X x Y series are CYM pixels). Accordingly, a determination is made as to whether the series X x And it is placed in the last column (decision block 68). In general, this means that the pixels of the X x series And (or second series) would be placed on the right edge of the bitmap that defines the image area. If the series X x And it is not placed in the last column (line 70), then the series X x Y (together with the series M x N) moves over a pixel or column to the right (block 72). The control then passes back to block 64 where the X x Y series is examined again for all indelible black. If the series X x Y is placed on the right edge of the bitmap and the result of the decision block 68 is YES (line 76), then a determination is also made whether the X x Y series is placed in the last row from the area of ima? ren (decision block 78). If the series X x Y is placed both in the last column and in the last row (line 80), then the method ends in 82. Alternatively, if the series X x Y is placed in the last column, but not in the the last row (line 84), then the series M x N and the series X x Y move down one row or pixel and the series X x Y is placed on the left edge of the image area (block 86). The control then passes back to block 64 via line 74. Although this invention has been described in terms of a preferred design, the present invention may be further modified within the spirit and scope of this disclosure. Accordingly, this application seeks to cover any variation, use or adaptation of the invention by the use of its general principles. Furthermore, this application attempts to cover such deviations from the present disclosure as long as they fall within the known or customary practice in the matter to which this invention pertains and which fall within the limits of the appended claims.

Claims (40)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property. A printing method using an ink jet printer that injects a first color ink and a second color ink onto a printing medium at locations defined by an image area having a plurality of pixels, inhibiting said method the bleeding between colors between the first color ink and the second color ink, said method comprising the steps of: selecting a first series of pixels in the image area, said first series comprising a series M x N, where M and N are whole; defining a portion of the first series as a second series of pixels, said second series comprising a series X x Y, where X and Y are integers, said integers X and Y being smaller than said integers M and N, respectively, and being minus one of said integers X x Y greater than 1; examining said pixels within said second series; and altering said pixels within said first series if said pixels examined within said second series correspond substantially all to the first color ink. The method according to claim 1, characterized in that said alteration step comprises the removal of a portion of available pixels within said first series on which a drop of ink can be deposited, said disposable pixels being removed in a board manner. The method according to claim 1, characterized in that said alteration step comprises the removal of at least a portion of available pixels within said first series on which a drop of ink can be deposited, said available pixels comprising all said pixels within said pixels. of said first series that are placed adjacent to said second series. The method according to claim 1, characterized in that it comprises the additional step of determining whether a predetermined percentage of said pixels within said first series, exclusive of said pixels within said second series, correspond to the second color ink, said step of altering said determination step and occurring only if said pixels within said first series corresponding to the second color ink are greater or equal to said predetermined percentage. The method according to claim 4, characterized in that said predetermined percentage is 50 percent. 6. The method according to claim 1, characterized in that said selecting step comprises associating said first series with a predetermined location on the image area, and comprising the additional steps of: associating said first series with a different predetermined location on the image area; and repeating said steps of examining an alteration. The method according to claim 6, characterized in that said second association step comprises the movement of said first series a distance of one pixel in a predetermined direction. The method according to claim 1, characterized in that said integers M and N are between 3 and 10, and said integers X and X are between 2 and 4. The method according to claim 8, characterized in that said integers M and N equal to 6 and said integers X and Y equals 2. The method according to claim 1, characterized in that said integer M equals said integer. N. The method according to claim 1, characterized in that said integer X equals said integer Y. 12. The method according to claim 1, characterized in that said altered pixels comprise pixels corresponding to locations on the printing medium on which injects the second color ink. The method according to claim 1, characterized in that the second color ink is selected from a blue, magenta and yellow ink. 14. The method according to claim 1, characterized in that the first color ink is an indelible black ink. The method according to claim 1, characterized in that said alteration step depends on a number of pixels within the first series corresponding to the second color ink. 16. A printing method using an ink jet printer that injects a first color ink and a second color ink onto a printing medium at locations defined by an image area having a plurality of pixels, inhibiting said method the bleeding between colors between the first color ink and the second color ink, said method comprising the steps of: selecting a first series of pixels in the image area, said first series comprising a series M x N, where M and N are whole; defining a portion of the first series as a second series of pixels, said second series comprising a series X x Y, where X and Y are integers, at least one of said integers X and Y being smaller than said integers M and N, respectively; examining said pixels within said second series; and altering said pixels within said first series, exclusive of said pixels within said second series, if at least about 50 percent of said pixels examined within said second series correspond to the first color ink. The method according to claim 16, characterized in that said alteration step is carried out if at least about 75 percent of said pixels examined within said second series correspond to the first color ink. The method according to claim 16, characterized in that said alteration step is carried out if at least about 90 percent of said pixels examined within said second series correspond to the first color ink. The method according to claim 16, characterized in that said alteration step comprises the removal of a portion of available pixels within said first series on which a drop of ink can be deposited, said disposable pixels being removed in a board manner. 20. The method according to claim 16, characterized in that said alteration step comprises the removal of at least a portion of available pixels within said first series onto which a drop of ink may be deposited, said disposable pixels comprising all said pixels within said first series that are deposited adjacent to said second series. The method according to claim 16, characterized in that it comprises the additional step of determining whether a predetermined percentage of said pixels within said first series, exclusive of said pixels within said second series, correspond to the second color ink, said step of altering said determination step and occurring only if said pixels within said first series corresponding to the second color ink are greater or equal to said predetermined percentage. 22. The method according to claim 21, characterized in that said predetermined percentage is 50 percent. The method according to claim 16, characterized in that said selection step comprises associating said first series with a predetermined location on the image area, and comprising the additional steps of: associating said first series with a different predetermined location on the area of image; and repeating said steps of examining an alteration. The method according to claim 23, characterized in that said second association step comprises moving a distance said first series of a pixel in a predetermined direction. The method according to claim 16, characterized in that said integers M and N are between 3 and 10, and said integers X and Y are between 2 and 4. 26. The method according to claim 25, characterized in that said integers M and N equals to 6 and said integers X and Y equal to 2. 27. The method according to claim 16, characterized in that said integer M equals said integer N. 28. The method according to claim 16, characterized in that said integer X equals to said integer Y. 29. The method according to claim 16, characterized in that said alteration step depends on a number of pixels within the first series corresponding to the second color ink. 30. A printing method using an ink jet printer that injects an indelible black ink and at least one additional color ink onto a printing medium at locations defined by an image area having a plurality of pixels, inhibiting said method the bleeding between colors between the indelible black ink and the at least one additional color ink, said method comprising the steps of: selecting a first series of pixels in the image area, said first series comprising a series M x N, being M and N integers; defining a portion of the first series as a second series of pixels, said second series comprising a series X x Y, where X and Y are integers, the integers X and Y being smaller than said integers M and N, respectively; said second series being centrally located within said first series; examining said pixels within said second series; and altering said pixels within said first series, exclusive of said pixels within said second series, if said pixels examined within said second series correspond substantially all to the indelible black ink. The method according to claim 30, characterized in that said alteration step comprises the removal of a portion of available pixels within said first series on which a drop of ink can be deposited, said disposable pixels being removed in a board manner. 32. The method according to claim 30, characterized in that said alteration step comprises the removal of at least a portion of available pixels within said first series onto which a drop of ink can be deposited, said available pixels comprising all said pixels within said pixels. of said first series that are placed adjacent to said second series. 33. The method according to claim 30, characterized in that it comprises the additional step of determining whether a predetermined percentage of said pixels within said first series, exclusive of said pixels within said second series, corresponds to the at least one additional color ink, said alteration stage depending on said determining step and occurring only if said pixels within said first series corresponding to the at least one additional color ink are greater than or equal to said predetermined percentage. 34. The method according to claim 33, characterized in that said predetermined percentage is 50 percent. The method according to claim 30, characterized in that said selection step comprises associating said first series with a predetermined location on the image area, and comprising the additional steps of: associating said first series with a different predetermined location on the area of image; and repeating said steps of examining an alteration. 36. The method according to claim 35, characterized in that said second association stage comprises the movement of said first series a distance of one pixel in a predetermined direction. 37. The method according to claim 30, characterized in that said integers M and N are between 3 and 10, and said integers X and X are between 2 and 4. 38. The method according to claim 37, characterized in that said integers and N equals to 6 and said integers X and Y equals 2. 39. The method according to claim 30, characterized in that the at least one additional color ink comprises at least one blue, magenta and yellow ink. 40. The method according to claim 30, characterized in that said alteration stage depends on a number of pixels within the first series corresponding to the second color ink.