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1. Field of the Invention
The present invention relates to a method of printing, and in particular, to a method of printing a borderless image onto a medium.
2. Description of the Related Art
When a printing apparatus prints an image on a medium, the size of the image printed is generally limited by a printable area. The printable area is usually defined by the printing apparatus and is limited by the medium chosen. The limitation is due to the fact that different printers have different medium tolerances, such as placement tolerance and width tolerance. As a result, each medium will have blank borders, which the printing apparatus will bypass during printing, even when the image to be printed has the same aspect ratio as that of the medium. Depending on the printing apparatus, the width of the blank borders ranges from 2 mm to 5 mm. In other words, while a majority of the medium is used, part of the medium is left blank. Not only are these borders undesirable to look at when left blank, a considerable amount of the potentially printable image data is sometimes left out of the image printed on the medium.
Accordingly, there is a need for a method of printing borderless images on media. In one form, the invention provides a method of printing a borderless image from original image data on a medium having medium dimensions and at least one medium tolerance. The method comprises the acts of determining a ratio between two dimensions of the original image data, and determining a sum between the at least one medium tolerance and one of the medium dimensions. Thereafter, the method comprises the acts of stretching one of the image dimensions to at most equal to the sum, and stretching the other image dimension based on the ratio and the increased image dimension.
In another form, the invention provides a method of printing a borderless image from original image data on a medium having medium dimensions, and at least one medium tolerance. The method comprises the acts of determining a ratio between two dimensions of the original image data, and matching one of the image dimensions of the original image data with one of the medium dimensions and one of the at least one medium tolerance. The method also comprises of the acts of stretching the image data based on the matched dimension, and stretching the other image dimension based on the ratio and the stretched image data.
In yet another form, the invention provides a printing apparatus adapted to print a borderless image from original image data onto a medium having medium dimensions and at least one medium tolerance. The printing apparatus comprises a ratio transformer to determine a ratio between two dimensions of the original image data, and to determine a sum between the at least one medium tolerance and one of the medium dimensions. The printing apparatus also comprises an image transformer to stretch one of the image dimensions to at most equal to the sum, and to stretch the other image dimension based on the ratio and the increased image dimension.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.
In the drawings:
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings.
Once a borderless print option has been selected, the original image is queued for processing or transforming before being printed. Initially, the transformation involves a controller 112 determining the dimensions of the original image, and determining an image aspect ratio using the dimensions of the original image. Specifically, the controller 112 includes a transformer 116 that manipulates the image data. For example, a ratio transformer 117 determines the image aspect ratio using the measured dimensions of the original image. Thereafter, the original image is stretched in an image transformer 118 according to the image aspect ratio determined and the medium parameters retrieved. Specifically, one of the original image dimensions, such as the width of the original image, is then stretched or increased in the image transformer 118 so that the stretched image dimension sufficiently covers a width sum of the corresponding medium width and the width tolerance associated with the selected medium. Using the determined image aspect ratio, the medium dimensions retrieved from the memory 108 and the width sum, the remaining image dimension is similarly stretched or proportionally increased. In this way, the stretched image keeps the same image aspect ratio, thus not distorting the image. The transformation process is detailed hereinafter.
The transformation process to produce a borderless copy specifically requires that the original image be stretched slightly in order to accommodate size and positional tolerances in the printing process. That is, the image stretching is used to insure the printed image goes to or beyond all medium dimensions and all tolerances. In this way, the transformation process and thus the printing process will cover the entire medium, and therefore yield a borderless copy of the original image.
The initial act in a borderless image stretching or transformation process is to increase the width of the original image sufficiently to cover the entire width of the medium including the tolerances on medium placement and medium dimensional tolerance. A typical medium placement tolerance is approximately ±1 mm, while a typical medium dimensional tolerance on the width is approximately ±2 mm. As a result, to completely include the width tolerance, the width of the original image can be increased horizontally by a sum of all the tolerances, 4 mm in the example. However, in order to reduce an ink overspray buildup on a side waste ink area, a width increment less than the sum of all the tolerances is generally chosen, for example, 3 mm. That is, the width of the original image is only transformed or incremented by the width increment amount, generally less than the sum of all the tolerances. Although the chosen width increment amount is less than the sum of all the tolerances, other transformations, increments, or stretching amounts can also be used depending on the printing apparatus requirements. However, the 3-mm width increment is generally acceptable because most printing medium tolerances, especially photo medium tolerances, are better than what the printing apparatus specifies.
Furthermore, in order to maintain the proportions or the aspect ratios of the original image, the other medium dimension of the original image such as the length is also proportionally stretched or transformed. Specifically, the other image dimension is stretched by a product between the image aspect ratio and the stretched image dimension. For example, if the width and the length of an image are 215.9 mm and 279.4 mm, respectively, the image aspect ratio between the length and the width is therefore 279.4/215.9=1.2941. If the width increment is 3 mm, the stretched image will have a width of (215.9 mm+3 mm)=218.9 mm. Thereafter, the length of the image is proportionally stretched to (218.9 mm×1.2941)=283.28 mm to maintain the original image aspect ratio.
Referring back to
The tolerated medium length is typically less than the length of a stretched image. That is, when comparing the length of the stretched image with the tolerated medium length at a comparator 119, a length difference or a medium delta is obtained. As a result, the medium delta is cropped or removed from the stretched image at the image transformer 118. For the example discussed, the stretched image has length of 283.28 mm, the tolerated medium length is 282.4 mm, and the medium delta is therefore 0.88 mm. Consequently, 0.88 mm of the stretched image length is cropped off. Column 220 of table 200 lists a plurality of crop amounts for different types of media. More specifically, the “Crop from Image Length” column 220 lists an amount of the “image stretched size” to be cropped by the image transformer 118 from the top of a stretched image before formatting for printing. The amount of cropping keeps the resultant printed image centered on a nominally sized medium and minimizes excessive ink overspray into the horizontal borderless waste ink areas. Also, the cropping is taken at the top of the stretched image to keep the center of the stretched image as close as possible to the center of the nominal medium. The “Printed Size” column 224 lists a resultant size of a formatted print image to be sent to the printing apparatus 100 after the cropping is performed.
After the original image has been incremented, stretched, transformed, and cropped to obtain the print image, the printing apparatus 100 can queue the image for printing. Assuming a printing apparatus having a printing resolution of 1/600″ per pel, the printing process generally starts at 0.5 mm or 12 pels before the nominal top edge of the medium, and 1 mm or 24 pels before the nominal left edge of the selected medium. Of course, other starting top edge pels and left edge pels can also be used depending on the printing apparatus, and the associated medium placement tolerances on the printing apparatus. That is, if the placement tolerance and the dimensional tolerance on a different printing apparatus are different, the starting top edge pels and the starting left edge pels will be different.
The controller 112 also generates a plurality of formatter codes in a formatter 120 and sends those codes to the printing apparatus 100 with the cropped image for printing. In one embodiment, the formatter 120 receives a stretched and cropped image with a length greater than the length of the chosen medium. For example, if the chosen medium is a letter size which has the dimensions of 8.5″×11″ (215.9 mm×279.4 mm), the formatter 120 will receive a formatted image that has a length of 11″+3 mm, and will generate formatter codes of a printing image with a length of 11″+3 mm.
In some embodiments, the processing unit 104 and its functions described are implemented in a combination of firmware, software, hardware, and the like. To be more specific, as illustrated in
Referring back to
When the printing apparatus 100 starts to print adjacent the top edge of the medium, a first group of the color print head nozzles 136 and a second group of the monochrome nozzles 140 are activated to spray ink onto the medium. Positioned beneath the top edge of the medium and these groups of print head nozzles 136, 140 is an absorbent pad or ink gutter to contain and to absorb any ink that is sprayed off the medium.
When printing portions 408 and 412 of the medium 400, the CMY print head generally uses a first number, for example 80 or nozzle 0 to nozzle 79, of the available 160 color nozzles 136. Meanwhile, the K print head 140 generally uses a second number, for example 160 black nozzles or nozzle 160 to nozzle 239 of nozzle column 316 and nozzle 480 to nozzle 559 of nozzle column 320, of the available 640 monochrome nozzles 140 to print. Therefore, a number of color nozzles and monochrome nozzles are not used during the printing process or the initial swaths around the top and bottom edges of the medium 400. Since a reduced number of the available nozzles are used, the printing controller 124 will control the medium feeding or advancing differently in a feeder 144, detailed hereinafter. As described, the number of the color nozzles per color used during the initial swaths is about half of the number of the monochrome nozzles, or 1-to-2 ratio. Furthermore, the number of CMYK nozzles used during the initial swaths is typically about half of all of the available nozzles. In this way, a shingling mode as is known by those of skill in the art can be used to print both borderless and bordered images. Thus, the printing apparatus 100 can provide a consistent print quality in both printing modes.
As the nozzles 136, 140, pass portion 408, the printing apparatus 100 will start to print in portion 404. During this passage, the printing apparatus 100, or the printing controller 124 will transition from using a subset of nozzles 136, 140 covered by the absorbent pad 324 to using, if needed, all the nozzles 136, 140. The transition specifically begins when a plurality of the leading nozzles 136, 140 positioned over by the absorbent pad 324 start printing on the portion 408 of
When printing with the color and photo print heads 128, all 80 color nozzles and all 80 photo nozzles covered by the absorbent pad 324 can be used to print the portion 408 of the medium 400 because the color and photo print heads 128 have a 1-to-1 head size ratio.
When the portion 412 is being printed, the printing process is similar. Specifically, when the portion 412 moves onto the print head 128 to be printed, the printing is delayed until the print head 128 is using the nozzles 136, 140 over the absorbent pad 324. Initially, when the portion 412 is about to reach the region of the pad 324, the feeder 144 changes the medium feed amounts from full advancing to a fraction of full advancing amount. Using CMYK with a 1200 dpi resolution and eight pass printing scheme as an example, the paper feed amounts in dots of the 1200 dpi resolution will change from a normal 37/41 dots sequence to the borderless 7/11 dots sequence. The smaller paper feed amounts can then be used to print the rest of the page.
To vertically align between print heads, if the absorbent pad 324 is large enough, the same absorbent pad 324 can be used. In this way, the controller 124 can continue to use C, M, and Y nozzles 0 to 79 and K nozzles 160 to 239 regardless of vertical alignment. On the other hand, the nozzles used in the nozzle columns can be changed to align the print heads so that the nozzles used are covering the same raster line of the image being printed. For example K nozzles 158 to 237 could be used instead of 160 to 239.
The image is subsequently stretched. Specifically, one of the original image dimensions, such as the width of the original image, is then stretched or increased at block 624 so that the stretched image dimension sufficiently covers the width sum as described earlier. Using the image aspect ratio determined at block 610, the medium dimensions retrieved from the memory 108 and the width sum, the second or the remaining image dimension is similarly stretched or proportionally increased at block 628. In this way, the stretched image keeps the same image aspect ratio, thus not distorting the image. Specifically, the other image dimension is stretched by a product between the image aspect ratio and the stretched image dimension at block 628. After the original image has been proportionally stretched in both dimensions, a medium delta as defined earlier is obtained at block 632 from the length of the stretched image and the medium tolerance in a manner discussed. The medium delta is then subtracted or cropped from the stretched image at block 636. The resulting image data is then formatted at block 640 for printing.
Various features and advantages of the invention are set forth in the following claims.