1. Field of Invention
This invention relates to a staggered full-width array printing system, and particularly to a set of staggered full-width array printbars comprised of die modules and more particularly to a first printbar comprised of a plurality of first die modules, for applying a first color, spaced substantially evenly apart so as to have gaps between each die module and located on a top surface of a first substrate, and a second printbar comprised of a plurality of second die modules, for applying a second color, different from the first color, spaced substantially evenly apart so as to have gaps between each die module and located on a bottom surface of the first substrate.
2. Description of Related Art
In an ink jet printing apparatus, individual drops of ink are ejected from a nozzle such that the droplet of ink travels under its own momentum towards a sheet of paper or other print medium on which drops of ink are intended to fall, with the impact areas overlapping so that they form characters or other marks of desired shape. In the ink jet printing apparatus, a printhead including a printbar with several die modules may be used with a plurality of individual nozzles in which to dispel the ink droplets. Such printheads are scanned across the medium to be marked in order to print the entire page.
Alternatively, with a page-width printhead, the printhead is stationary and dispels ink onto the medium from the top of the medium to the bottom. With a page-width printhead, the printhead will include a full-width printbar with several die modules accurately positioned with respect to each other so that the line of picture elements (pixels) produced by printed droplets from neighboring modules show no seams, and the pixels appear to be produced by one continuous line of uniformly spaced ink drop nozzles. An ink may be deposited onto the print medium one line at a time by the full-width printbar as the paper passes by until full-page images are completed. This type of ink jet printing process uses a single pass method and is known as a “full-width array” printer.
Various methods are known for fabricating full-width array printbars. One method is to form a linear pagewidth printbar by providing end-to-end abutment of fully functional printhead elements (die modules) on a substrate. This type of arrangement is termed buttable or butted. In other words, each of the die modules are positioned joined end to end with respect to each other such that the die modules together make up the print region of the print medium. The die modules are positioned end to end so that the pixels produced by from neighboring modules show no seams, and the pixels appear to be produced by one continuous line of uniformly spaced ink drop nozzles. U.S. Pat. Nos. 5,192,959, 4,999,077, and 5,198,054 disclose processes for forming linear printbars of butted subunits.
Because each of the die modules are positioned joined end to end with respect to each other on a single substrate such that the die modules together make up the print region of the print medium, only one full width printbar is necessary, for example, with a black ink only system. Additional full-width color printbars may be added to enable a highlight or full color printer.
In a multi-color ink jet printing process, several full-width array printbars are used in a printer to deposit different color inks onto a print medium to give full color images. The different color inks comprise, for example, black, cyan, magenta, and yellow inks.
U.S. Pat. Nos. 5,280,308, 5,343,227, and 5,270,738 disclose full color pagewidth printers with four printbars, black, cyan, magenta, and yellow; and U.S. Pat. Nos. 5,192,959, 4,999,077, and 5,198,054 disclose processes for forming linear printbars of butted subunits.
However, in a full-width array printbar with die modules abutted end to end, the joints between successive die modules make it difficult to accurately and precisely print on a print medium. For example, one configuration includes a number of die modules 12 butted together on a substrate 14, as shown in
Another method for fabricating a full-width printbar is to provide same color die modules as two separated printbars. This type of arrangement is referred to as nonbuttable as the die modules of the printbars are not abutting each other. Die modules of the first printbar are spaced substantially evenly apart, creating a gap between each of the die modules. Die modules of the same output color are then located on the second printbar in a spaced apart manner such that they align with the gaps between the die modules on the first printbar. The die modules of the two printbars thus overlap so that the die modules of the two printbars together make up the print region of the print medium, as shown in FIG. 3. The die modules 12 of the first printbar 16 are spaced substantially evenly apart on the first substrate 18 creating gaps 20 between each of the die modules 12. Die modules 12 of the second printbar 17 are also spaced substantially evenly apart on the second substrate 22, but are spaced such that they cover the gaps 20 between the die modules 12 on the first substrate 18. The die modules 12 of the two printbars 16 and 17 overlap.
In other words, the die modules 12 of the two printbars 16 and 17 are staggered to form a checker board pattern, but also overlap each other. For this arrangement, two printbars are required for each color to be printed. Thus, for a four-color printer, for example, eight printbars on eight substrates are required.
With respect to the configuration illustrated in
Alternatively, in order to reduce the space required for the nonbuttable array that requires two printbars 16 and 17 for each color and uses two substrates 18 and 22 as in
However, in the ink jet printer disclosed by Kneezel, as ink is dispersed from the right side up die modules and ink is also dispersed from the upside down die modules, different intensity, brightness, tone, volume, and/or the like of the color ink may result, leading to color distortion.
Thus, a more compact full-width array printer with improved print quality is needed.
A further consideration when designing a pagewidth color printer is the cost and maintenance of the full-width printbars. Reducing the number of required substrates in a printhead would result in fewer parts and less maintenance.
A more compact printer that does not detract from the integrity of the ink printout is needed.
There is a need for a more compact nonbuttable full-width array color printer.
There is also a need to increase the speed of color printers without detracting from the color integrity or uniformity of the image printed.
There is a need for a color printer with nonbuttable full-width array printbars with enhanced colors for printed color images and having a fuller range of colors.
The above and other advantages are achieved by various embodiments of the invention.
In exemplary embodiments, fewer printbars are required for a more compact printer structure.
In exemplary embodiments, the configuration of the printbars may provide enhanced color images.
In exemplary embodiments, the configuration of the printbars may provide greater uniformity of colors.
In exemplary embodiments, the configuration of the printbars may provide greater integrity of colors.
As used herein, the term “printbar” is used to refer to a single row of a plurality of substantially aligned die modules. The row of die modules is preferably substantially aligned with respect to a line parallel with a top edge of a print medium to be printed upon, i.e., aligned across the width of the print medium. Each of the substantially aligned die modules of a printbar are typically mounted upon a substrate. The substrate for a single printbar may either be continuous or discontinuous.
Although two complementary printbars for each of the four colors, or eight printbars in total (each on its own substrate), is commonly used, an additional set of two printbars, each mounted on respective substrates, for each of possible additional colors, such as, for example, light cyan or light magenta, may be added. Thus, the total number of printbars and substrates may be greater than eight, for example, twelve, or the like. In the configuration of
An advantage of the configuration of the present invention is that the total number of substrates employed is equal to the number of colors to be printed. Specifically, where X represents the total number of colors that can be applied by the printhead, the total number of substrates Y of the printhead in the present invention satisfies the relationship X=Y.
Further, the printhead further comprises at least one ink supply line for each of the X number of different colors that supply a colored ink to the die modules that print that colored ink.
Referring to
For example, the first printbar 27 for magenta 60 has three magenta colored die modules 26 spaced substantially evenly apart located on the top surface 28 of the substrate 30. The associated second printbar 29 for magenta 60 has four magenta colored die modules 32 spaced substantially evenly apart located on the bottom surface 34 of the substrate 30. The evenly spaced die modules 26 on the top surface 28 of the substrate 30 are vertically aligned with the gaps 31 exposed on the bottom surface 34 of the substrate 30. The complementary sets of same output color die modules on each surface of the common substrate are thus aligned so as to cover the gaps between die modules of the associated printbar on the opposite surface of the substrate.
As shown in
Referring to
In an embodiment of the present invention, the configuration of the printbars is varied to improve the resulting print quality. More specifically, the printbars mounted on the substrates are configured such that all die modules for applying a specific color are either upside down or right side up, but not both.
A first embodiment of the invention is shown in
Further, the top surface 70 of the third substrate 76 has die modules 47 with one ink color and the bottom surface 71 of the third substrate 76 has die modules 48 for outputting a different, second color. Here, die modules 47, for outputting cyan ink/toner, are on the top surface 70 of the third substrate 76 and die modules 48 for outputting black ink/toner are located on the bottom surface 71 of the third substrate 76. The next adjacent substrate (i.e., the fourth substrate 78) below the third substrate 76 includes the same color die modules on the top and bottom surfaces as the third substrate 76, i.e., cyan die modules 47 on the top and black die modules 48 on the bottom. Here, each of the die modules on this fourth substrate 78 are staggered with respect to the corresponding same color die modules on the third substrate 76.
In such a configuration, all of the yellow die modules 45 and cyan die modules 47, for example, are located right side up, on the top surface of respective substrates. Thus, the relative location of the discharged main drop 62 and satellite drops 64 may be substantially uniform across the printed page for the yellow and cyan dies. Likewise, all of the magenta die modules 46 and black color die modules 48 are located up side down, on the bottom surface of respective substrates. Thus, the relative location of the discharged main drop 62 and satellite drops 64 may be substantially uniform across the printed page for the magenta and black dies.
Further, with the printbars illustrated in
Other embodiments of this concept showing different orientations of the colors black, yellow, magenta and cyan are shown in
The yellow and magenta die modules may both be used to print a color red. Referring to
In another embodiment of the present invention, the configuration of the printbars on the substrates is varied to improve the resulting print quality. The print quality is improved by preserving the order in which ink is deposited across the page. More specifically, as paper moves past the set of printbars, the color order will be the same across the page.
Referring to
Because die modules of the printbars for each of the colors is located either up side down or right sight up, but not both, the issue of distortion of color due to offset satellite drops of ink is addressed. Further, the colored ink will be printed in a specific order such that color distortion will be avoided.
For example, as discussed above, to print the color red, the yellow and the magenta die modules are used. In this case in any location on the printing region for each die module, yellow will always be printed first, and then magenta. Of course, any number of colors may be added to this embodiment. For example, in a six color printer with reduced number of substrates in an embodiment of this invention, six substrates may be provided. Further, any color order may be used as long as the location of the color (either on the top surface or bottom surface of the substrate, but not both) is consistent.
Referring to
It is envisioned that the embodiments of the present invention may include any number of variations in printbars, such as, for example, printbars with die modules of varying colors, printbars that disperse ink in volumes of varying amounts to effect a better range in colors, and the like.
Further, the described embodiments may be used with any number of printers including thermal ink jet printers and the like. The described embodiments may be used with copiers, facsimile machines, or any equipment in which multiple colors are being printed.
Those skilled in the art will recognize that certain variations and/or additions can be made in these illustrative embodiments. It is apparent that various alternatives and modifications to the embodiments can be made thereto. It is, therefore, the intention in the appended claims to cover all such modifications and alternatives as may fall within the true scope of the invention.
Number | Name | Date | Kind |
---|---|---|---|
4999077 | Drake et al. | Mar 1991 | A |
5192959 | Drake et al. | Mar 1993 | A |
5198054 | Drake et al. | Mar 1993 | A |
5257043 | Kneezel | Oct 1993 | A |
5270738 | Takahashi et al. | Dec 1993 | A |
5280308 | Takahashi et al. | Jan 1994 | A |
5343227 | Hirosawa et al. | Aug 1994 | A |
6352329 | Watanabe et al. | Mar 2002 | B1 |