Abstract:
Ink jet printing apparatus for forming a plurality of ink images on receivers in response to one or more digital image file(s) each including at least one or more digital images and information indicating the number of ink images to be made. The ink jet printing apparatus includes at least one ink jet print head adapted to deliver ink to the receiver and at least two receiver webs. The ink jet printing apparatus selectively moves one or more receiver webs along a receiver path past the ink jet print head. A control circuitry responsive to the digital image file(s) determines the locations of the ink images to be formed on the two receiver webs in such a manner that minimizes receiver waste. The ink jet printing apparatus actuates the ink jet print head(s) to form ink images on the receiver webs, whereby receiver waste is minimized.

Description:
Reference is made to commonly assigned U.S. patent application Ser. No. 09/182,711, filed Oct. 29, 1998 to Wen et al., entitled “Format Flexible Ink Jet Printing”; U.S. patent application Ser. No. 09/182,351, filed Oct. 29, 1998 to Wen et al., entitled “Large and Small Format Ink Jet Printing Apparatus”, and concurrently filed U.S. patent application Ser. No. 09/209,359 to Wen et al., entitled “Ink Jet Printing Having Format Flexibility and Reduced Receiver Waste”. The disclosures of these related applications are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an ink jet printing apparatus that can provide ink images in different format sizes on receivers in a fashion in which the receiver waste is minimized. 
     BACKGROUND OF THE INVENTION 
     Ink jet printing has become a prominent contender in the digital output arena because of its non-impact, low-noise characteristics, and its compatibility with plain paper. Ink jet printing avoids the complications of toner transfers and fixing as in electrophotography, and the pressure contact at the printing interface as in thermal resistive printing. Ink jet printing mechanisms include continuous ink jet or drop-on-demand ink jet. U.S. Pat. No. 3,946,398, which issued to Kyser et al. in 1970, discloses a drop-on-demand ink jet printer which applies a high voltage to a piezoelectric crystal, causing the crystal to bend, applying pressure on an ink reservoir and jetting drops on demand. Piezoelectric ink jet printers can also utilize piezoelectric crystals in push mode, shear mode, and squeeze mode. EP 827 833 A2 and WO 98/08687 disclose a piezoelectric ink jet print head apparatus with reduced crosstalk between channels, improved ink protection, and capability of ejecting variable ink drop size. 
     U.S. Pat. No. 4,723,129, issued to Endo et al, discloses an electrothermal drop-on-demand ink jet printer which applies a power pulse to an electrothermal heater which is in thermal contact with water based ink in a nozzle. A small quantity of ink rapidly evaporates, forming a bubble which causes an ink drop to be ejected from small apertures along the edge of the heater substrate. This technology is known as Bubblejet™ (trademark of Canon K.K. of Japan). 
     U.S. Pat. No. 4,490,728, which issued to Vaught et al. in 1982, discloses an electrothermal drop ejection system which also operates by bubble formation to eject drops in a direction normal to the plane of the heater substrate. As used herein, the term “thermal ink jet” is used to refer to both this system and system commonly known as Bubblejet™. 
     One advantage of ink jet printing is its capability in printing large-format images. A relatively narrow print head can print a large image on a receiver by scanning across the large printing area in multiple passes. The currently commercial large-format ink jet printers can provide ink images in the widths of 36″ to 62″. In contrast, a thermal resistive printer utilizes a page-wide print head. The colorants are transferred from a donor web to a receiver at the pressure contact interface between the page-wide print head and the receiver. The manufacturing difficulties and cost make it unfeasible for thermal resistive print head to be wider than a double-page size. 
     The advancement of ink jet printing technologies has also opened up opportunities in photographic printing for applications in photo minilabs and photo microlabs. In these environments, the ink jet printing techniques have the advantages of easy image manipulation, compatibility with digital image files, and faster turn-around time. When configured properly, ink jet printers can deliver images with qualities comparable to that of the traditional photographs. The typical photographic formats include 3R (3.5″×5″), 4R (4″×6″), page size (8.5″×11″) etc. For a given width (e.g. 3.5″, 4″, 5″), the image length can also vary (e.g. from 5″ to 12″) from Classic, to HDTV and Panoramic format. 
     In commercial ink jet printing, it is very desirable to have one ink jet printer to print ink images in both large formats (3′×4′) and traditional photographic formats. The service provider can then provide traditional photographs with added digital features and flexibility as well as poster-sizes ink images for displays for home, offices, signage, and graphic art applications. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an ink jet printing apparatus for make ink images in variable and flexible formats while at the same time minimizing the waste of receiver material. In the field of photographic printing, the receiver waste is referred to as paper slugs. The receiver waste is undesirable because it increases the cost of receiver per unit area. Moreover, removing receiver waste increases the operation time and decreases throughput. 
     A further object of the present invention is to provide an ink jet printing apparatus that can effectively provide prints with ink images in traditional photographic formats as well as large formats. 
     Another object of the present invention is to provide an ink jet printing apparatus that can effectively provide ink images in small and large formats in a fashion that maximizes receiver usage. 
     These objects are achieved by ink jet printing apparatus for forming a plurality of ink images on receivers in response to one or more digital image file(s) each including at least one or more digital image(s) and information indicating the number of ink images to be made, comprising: 
     a) at least one ink jet print head adapted to deliver ink to the receiver; 
     b) means for providing at least two receiver webs; 
     c) moving means for selectively moving one or more receiver webs along a receiver path past the ink jet print head; 
     d) control means responsive to the digital image file(s) for determining the locations of the ink images to be formed on the two receiver webs in such a manner that minimizes receiver waste; and 
     e) means coupled to the control means for actuating the ink jet print head to form ink images on the receiver webs, whereby receiver waste is minimized. 
     ADVANTAGES 
     An advantage of the present invention is that multiple ink image sizes can be provided by one ink jet printing apparatus. The printed ink images can be cut to the desired dimensions by two receiver cutters. The format of the prints with ink images can include the traditional photographic sizes and large format sizes. 
     Another advantage of the present invention is that the ink images can be printed on a plurality of ink receivers of different widths to facilitate maximum receiver usage thereby minimizing the waste of receiver material. The receivers of different widths can be simultaneously or separately transported by a receiver transport mechanism to respective printing positions. 
     A further advantage of the present invention is that the printing throughput is increased by printing a plurality of ink images in long printing passes. Furthermore, ink images of different formats can be printed without changing the receiver supplies and thereby also reducing operation time. 
     Yet another advantage of the present invention is that a time delay is provided after the printing of ink images and before the printed receivers are cut to proper sizes and stacked in a print tray, thereby permitting proper drying of the ink images. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial perspective of an ink jet printing apparatus in accordance with the present invention; 
     FIG. 2 is a partial top view of the ink jet printing apparatus of FIG. 1; 
     FIG. 3 shows a receiver transport configuration for printing ink images on a wide receiver web; 
     FIG. 4 shows a receiver transport configuration for simultaneously printing ink images on a narrow and a wide receiver webs; 
     FIG. 5 shows a receiver transport configuration for printing ink images on a narrow receiver web; 
     FIG. 6 shows the configuration of the transmission system for printing ink images on a wide receiver web; 
     FIG. 7 shows the configuration of the transmission system for simultaneously printing ink images on a narrow and a wide receiver webs; 
     FIG. 8 shows the configuration of the transmission system for printing ink images on a narrow receiver web; 
     FIG. 9 shows a layout of ink images and the receiver waste when the ink images are formed only on the wide receiver web but not on the narrow receiver web; 
     FIG. 10 shows a layout of ink images formed on the wide and the narrow receiver webs and how receiver waste is minimized; and 
     FIG. 11 shows a flow chart of the operational steps for minimizing receiver waste in the ink jet printing apparatus in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is described with relation to an ink jet printing apparatus that can provide ink images in different size formats on receivers. 
     A partial perspective and a partial top view of an ink jet printing apparatus  10  in accordance with the present invention are shown in FIG.  1  and FIG.  2 . For clarity, only the essential components in the ink jet printing apparatus are shown for illustrating the invention. 
     Referring to FIGS. 1 and 2, an ink jet printing apparatus  10  comprises a computer  20 , a film scanner  21 , a compact disk (CD) drive  22 , control electronics  25 , print head drive electronics  30 , a plurality of ink jet print heads  40 , a display panel  45 , receiver transport mechanism  55 , and print head transport mechanism  65 . The display panel  45  has a touch-sensitive screen that can display information or receive input from a user or an operator. The ink jet printing apparatus  10  also includes a right frame housing  75  and a left frame housing  76 . 
     The computer  20  receives a digital image file from a film scanner by scanning a photographic film (e.g. 35 mm, Advanced Photo System, slide film, etc.), or from a CD such as Picture CD, Photo CD, CD-ROM or DVD through the CD Drive  22 . The digital image can also be transferred from a digital network or from a digital camera. Information about the digital images and printing modes of these images can be received from the display panel  45 . 
     The digital image file in the computer  20  can include a plurality of digital images. Each digital image can include several color planes such as yellow, magenta, cyan, and black. The digital image file includes the desired image format to be printed on a narrow ink receiver  49  and a wide ink receiver  50 , for each digital image. The image format includes the formats well known in the art such as 3″×5″ (3R), 4″×6″ (4R), high definition TV (HDTV), or panorama. The digital image file includes the number and the preferred sequence of the ink images to be printed. For example, a digital image file can be obtained by scanning a roll of 24 exposure 35 mm photographic film using the film scanner  21 . A double prints and an index print can be requested by the customer. In this example, there are 49 ink images to be printed. The preferred sequence is often preferably the chronicle sequence when the photographs were taken. The digital image file can also include information such as the time, the location, the scene, exposure conditions, annotations etc. related to each digital image. The digital image file can also include large format digital images such as 11″×17″, 3′×4′, 4′×5′, and other poster sizes. The width of the ink image can span substantially the full width of the narrow ink receiver  49  or the wide ink receiver  50 . The ratio of the length to the width of the print having an ink image is referred as the aspect ratio. A user or an operator can input information such as above to be included in the digital image file using the display panel  45 . The user can also input information about the annotation that he or she wants to appear on the ink images. 
     After receiving the digital image file(s), the computer  20  performs image processing on each individual digital image. As it is well known in the art, the image processing can include re-sizing, tone scale and color calibration, halftoning, swath cutting, and so on. Annotation information will be composed into the digital images as well. In the present invention, a plurality of digital images often need to be composed into a large digital image file. In this way, the ink jet print heads  40  can print a portion from each of several different ink images as the ink jet print heads  40  scan along print head scanning direction  70  in one printing pass. 
     As described below, the computer  20  analyzes the total number of ink images to be printed for each print job and maximizes the packing efficiency of the ink images on both the narrow ink receiver  49  and the wide ink receiver  50  such that receiver waste is reduced. Those skilled in the art will appreciate, although a plurality of ink jet print heads are preferred, a single ink jet print head that prints one or several color inks can also be used, especially if it is aligned across the print width  92 . A print job is typically requested by one customer and can contain one or more digital image files. 
     The receiver transport mechanism  55  in the ink jet printing apparatus  10  can move the narrow ink receiver  49  and the wide ink receiver  50  along a first receiver path  60 . The term receiver path means that the receivers  49  and  50  can be moved to a position where ink images  80  and  90  can be formed by the ink jet print heads  40 . The narrow ink receiver  49  and the wide ink receiver  50  are provided, in the form of a web, by a narrow receiver roll  56  and a wide receiver roll  57  that are wound around a shaft  58 . Receiver sensors (not shown) are provided in positions adjacent to the first receiver path  60  for detecting the lead edges of the narrow ink receiver  49  and the wide ink receiver  50 . Such sensors send signals to the control electronics  25  defining the positions of the lead edges. The receiver transport mechanism  55  is controlled by the control electronics  25 . As shown in FIG. 1, the narrow receiver roll  56  and the wide receiver roll  57  can be easily loaded and off-loaded for receiver change-over for loading new receiver rolls or receiver rolls of different widths. However, the presence of the narrow and wide receiver rolls can satisfy most of the printing needs at different formats. The frequency for receiver change-over is reduced and the printing throughput is therefore increased. For example, the width of the wide receiver roll  57  can range from 17″, 20″, 36″ to 42″; the width of the narrow receiver roll  56  can range from 3.5″, 4″, 8″, 10″. A user or operator of the ink jet printing apparatus  10  can provide a user input to the display panel  45  representing the receiver width  59  of the wide ink receiver  50  on the wide receiver roll  57  as well as similar information on the narrow receiver roll  56 . The computer  20 , in response to this receiver width  59 , composes digital images and operates the position of the ink jet print heads  40  to form ink images  80  and  90 . These images  80  and  90  are properly positioned on the narrow ink receiver  49  and the wide ink receiver  50  to minimize receiver waste. 
     As shown in FIGS. 3,  4  and  5 , the narrow ink receiver  49  and the wide ink receiver  50  can be moved simultaneously or separately, depending on the specifics of the applications, by the receiver transport mechanism  55 . In particular, the narrow ink receiver  49  and the wide ink receiver  50  are respectively driven by capstan rollers (not shown) through capstan rollers  605  and  625  and pinch rollers (not shown). The transport of the narrow ink receiver  49  and the wide ink receiver  50  is actuated by the transmission system  600  under the control of the control electronics  25 . Details of the operation of the transmission system  600  are shown in FIGS. 6-8. 
     FIG. 6 shows the transmission system  600  that drives either or both capstan rollers  605  and  625 . The transmission system  600  as will be described has a plurality of selectively engagable gears for moving one or more receiver webs separately or simultaneously. A motor  615  is mounted to the transmission housing  601 . A motor shaft  620  is mounted to a transmission housing  601  and keyed to the motor  615 . A driving gear  630  that is mounted on the motor shaft  620  can be driven by the motor  615 , in either clockwise or counterclockwise directions. An idler shaft  610  is also mounted to the transmission housing  601 . Gears  635 ,  640 ,  645 , and  650  are mounted to idler shaft  610 . Gears  635  and  640  are in constant mesh with gear  630  and can rotate about the shaft  610 . The gears  635  and  640  are adapted to be slid transversely along shaft  610  under the control of a solenoid and a shift lever (not shown) under the control of the control electronics  25 . Gears  645  and  650  are transversely retained on shaft  610  but are also free to rotate on shaft  610 . 
     In FIG. 6, teeth  665  of gears  635  and  645  are disengaged whereas the teeth  665  of gears  640  and  650  are engaged. When the motor  615  drives the gear  630 , the gear  645  remains stationary while gear  650  rotates. The gear  650  drives the output gear  660  which further drives the capstan roller  605  for moving the wide ink receiver  50 . 
     FIG. 7 shows the transmission system  600  wherein the gear  635  has been moved transversely by the solenoid (not shown) so that the teeth  665  of the gears  635  and  645  and the gears  640  and  650  are both engaged. Two pairs of gears are now rotated at the same angular velocity under the control of the control electronics  25 . The gear  645  drives the output gear  655  which is keyed to the capstan roller  625  for moving the narrow ink receiver  49 . Simultaneously, the gear  650  drives the output gear  660  which further drives the capstan roller  605  for moving the wide ink receiver  50 . 
     FIG. 8 shows the transmission system  600  except now gear  635  has been moved transversely by the solenoid and the shift lever (not shown) so that the teeth  665  of the gears  635  and  645  are engaged and the teeth  665  of the gears  640  and  650  are disengaged. The gears  635  and  645  now rotate with the same angular velocity. The gear  645  drives the output gear  655  which is keyed to the capstan roller  625 . Only the narrow ink receiver  49  is transported. 
     The ink jet printing apparatus  10  also includes ink reservoirs (not shown) for providing colored inks to the ink jet print heads  40 . The ink jet printing apparatus  10  can also include print heads and ink reservoirs for printing and storing other color inks such as black, green, red, orange, gold, as well as inks of the same color but of different concentrations such as light cyan and light magenta inks. 
     The computer  20  can contain one or more digital image files each including at least one digital image. The computer  20  controls the print head drive electronics  30  according to the digital image file(s) to actuate and thereby cause the ink jet print heads  40  to print color images on the narrow ink receiver  49  and the wide ink receiver  50 . During printing, the print head drive electronics  30  produces signals corresponding to image data from one or more than one digital image files. Each digital image file can include a plurality of digital images. A plurality of ink images (such as duplicates) can also be printed corresponding to each digital image, as defined in the digital image file or by user input to the computer  20  via display panel  45 . 
     The ink jet print heads  40  can be a unitary structure or each print head can be separate for printing colored inks. Each ink jet print head  40  includes a plurality of ink nozzles and associated ink drop activators for delivering different color ink drops to the narrow ink receiver  49  and the wide ink receiver  50 . The ink jet print heads  40  can be narrow print heads that print across the narrow ink receiver  49  and the wide ink receiver  50  in a raster or swath fashion. The ink drop ejection can be actuated from the ink nozzles by the ink jet activation means well known in the art, for example, piezoelectric actuators or thermal electric actuators. The ink jet print heads  40  are transported by the print head transport mechanism  65  along the guiding rail  67  under the control of the control electronics  25 . The ink jet print head  40  is connected with a flexible connector  68 . The flexible connector  68  houses the electric data cables from the print head drive electronics  30  to the ink jet print heads  40  and the ink lines that supply color inks to the ink jet print heads  40 . The ink jet print heads  40  scans and prints in print head scanning direction  70  across the first receiver path  60  in one printing pass. The narrow ink receiver  49  and the wide ink receiver  50  are moved along the first receiver path  60 . The next pass is subsequently printed. The ink jet print heads  40  can print either in one direction or bidirectionally. In operation, they are moved across the receiver in each pass. In a bidirectional mode, they are not returned to a home position, but are traversed in a direction opposite to the first pass. 
     In accordance with the present invention, still referring to FIGS. 1 and 2, the ink jet printing apparatus  10  also includes a first receiver cutter  100  and a second receiver cutter  220 . The first receiver cutter  100  and the second receiver cutter  220  are actuatable by the control electronics  25 . The first receiver cutter  100  is preferably a cutting wheel, which is commonly in large-format ink jet printers. The second receiver cutter  220  preferably has two spaced apart and parallel blades so that in operation it will cut off the border in between two sequential images at each cut. Those skilled in the art will appreciate that the arrangement can be made so that the distance between blades is adjustable. The first receiver cutter  100  is movable across the narrow ink receiver  49  and the wide ink receiver  50  along the first cutting direction  105  under the control of control electronics  25 . The control electronics  25  can vary the width of the prints and the length of the prints can also be varied by operating the cutters  100  and  220 . 
     A receiver transport shelf  145  is provided at the exit end of the first receiver path  60  for sorting the large and small format prints. On the receiver transport surface  146  of the receiver transport shelf  145 , there is provided a plurality of rotatable cone-shaped rollers  150 . A receiver registration plate  147  is positioned against the outside edge of the receiver transport surface  146 . The receiver registration plate  147  is moved up and down by a platen transport mechanism  165 . The cone-shaped rollers  150  are oriented such that the ends of larger-diameter are pointed toward the receiver registration plate  147 . When actuated, as described below, these cone-shaped rollers  150  can transport an ink image set  110  along the second receiver path  160  while aligning the ink image set along the receiver registration plate  147 . 
     The receiver registration plate  147  is disposed adjacent to the receiver transport shelf  145  and movable by the receiver platen mechanism  165  between a first blocking position (shown in FIGS. 4 and 5) for printing small-format images to a second unblocking position (shown in FIG. 3) for printing large-format images. The cone-shaped rollers  150  are rotated by a motor (not shown) which is under the control of platen transport mechanism  165 . After the narrow ink receiver  49  and the wide ink receiver  50  are cut by the first receiver cutter  100 , the receivers having the ink image  112  and the ink image set  110  drop onto the receiver transport surface  146  (shown in FIG.  4 ). The platen transport mechanism  165  causes the cone-shaped rollers  150  to register the receiver against the receiver registration plate  147  and advance the receiver to the second receiver cutter  220  where the prints  240  are cut to desired sizes. The prints  240  are then placed into print tray compartments  255  of the print tray  250 . 
     FIGS. 3 and 6 show the receiver transport configuration when a large format ink image  79  is in the process of being printed. When a large format ink image  79  of full receiver width  59  is to be printed as defined by a digital image file and the user input, the receiver registration plate  147  is moved down by a platen transport mechanism  165 . The wide ink receiver  50  carrying the large format ink image  79  is transported passing the receiver transport shelf  145 . The wide ink receiver  50  large format ink image  79  can then be wound to a roller (not shown) or dropped to a large receiver tray similar to the commercial large format ink jet printers. It should be noted that the ink jet printing apparatus  10  can print a single digital image on the wide ink receiver  50  as a large format ink image as described above. 
     FIGS. 2,  4  and  7  show the receiver transport configuration when a plurality of small-format ink mages are in the process of being printed. The narrow receiver roll  56  and the wide receiver roll  57  are first transported simultaneously to printing positions by the receiver transport mechanism  55  under the control of the control electronics  25 . The configuration of the transmission system  600  is shown in FIG.  7 . 
     Ink images  78 ,  80  and  90  corresponding to these digital images can be conveniently defined to be the same as the formats corresponding to silver halide photographs such as 3.5″×5″ (3R), 4″×6″ (4R), high definition TV (HDTV) (4″×7″), or panorama (4×11.5″). In the present invention, the two dimensions of the ink images  78 ,  80  and  90  are referred as the print width  92  and the print length  93  (as shown in FIG.  2 ). Preferably, the ink images  78 ,  80  and  90  that are distributed across the first receiver path  60  will have the same print width  92 . The ink images  78 ,  80  and  90  are distributed on the narrow ink receiver  49  and the wide ink receiver  50  to minimize the unprinted area ( 946  in FIG. 9) to reduce waste. For ink images  80  and  90  of the same print width  92 , the print length  93  can vary depending on the specific format of each ink image. For example, the print width  92  of the ink images  80  and  90  can be 4″. The 4R, HDTV, and panoramic formats require the print lengths  93  to be 6″, 7.5″, 10″, 11″ and 12″, respectively. 
     Still referring to FIGS. 2,  4  and  7 , after the set of small-format ink images  78 ,  80  and  90  are printed across the first receiver path  60 , the narrow ink receiver  49  and the wide ink receiver  50  are cut by the first receiver cutter  100  along the first cutting direction  105  to form ink image  112  and ink image set  110 . The ink images  80  and  90  preferably have the same print width  92 . Since borderless prints are often desired for simulating the traditional photograph, the image borders can be cut off along the side of the print lengths of the ink images  80  and  90 . Although not shown, the image borders can be dropped to a slug container. The ink images  80  and  90  in an ink image set  110  can be separated by unprinted areas across the first receiver path  60 . Furthermore, separation marks can also be printed by the ink jet print heads between the ink images  80  and  90 . The separation masks can be encoded to carry the information about the length of the ink image following the separation mark along a second receiver path  160  which is perpendicular to the first receiver path  60 . 
     When small format ink images  80  and  90  are printed, according to the digital image file and the user input, the receiver registration plate  147  is moved up by the platen transport mechanism  165 . After the first receiver cutter  100  performs its cutting operation, the ink image set  110  is formed on the receiver. The ink image set  110  is shown to include a plurality of ink images  170 ,  180 ,  190 . The ink image set  110  transferred onto receiver transport shelf  145 . The upward positioned receiver registration plate  147  limits the movement of the ink image set  110  in the direction of the first receiver path  60 . The cone-shaped rollers  150  are actuated by the platen transport mechanism  165  to move the ink image set  110  along the second receiver path  160 . The platen transport mechanism  165  is under the control of the control electronics  25 . As described above, the cone-shaped rollers  150  drive the ink image set  110  to be aligned to the receiver registration plate  147  during the movement along the second receiver path  160 . If needed, the ink image set  110  can be moved back and forth relative to the second receiver path  160  to move the ink image set  110  to be in contact with the receiver registration plate  147 . The ink image set  110  is transported by the cone-shaped rollers  150  to a receiver cutter device  200 . The receiver cutter device  200  includes a receiver detector  210  and a second receiver cutter  220 . 
     As the ink image set  110  is moved through the receiver cutter device  200 , the receiver detector  210  detects the lead edge of the ink image set  110 . The receiver detector  210  can also detect the unprinted area, separation arks, or borders between the ink images  170 ,  180 , and  190 . The receiver detector sends signals to control electronics  25  which sends a receiver position signal further to computer  20 . The computer  20  calculates the border positions of the ink images  170 ,  180 ,  190  of the ink image set  110 . The computer  20  then controls the control electronics  25  to actuate the second receiver cutter  220  to sequentially cut the ink image set  110  to remove portions of the receiver between the printed ink images  170 - 190  as waste and forms the prints  240 . The waste or slug is dropped into a slug container  230 . In this way, separate prints  240  having ink images of a desired size are formed in response to a digital image file. The prints  240  are placed and stacked in a print tray  250 . The print tray  250  can include a plurality of print tray compartments  255 , each of which can be used to store a group of prints  240 . It is often desired to store the prints  240  from the same customer or prints of the same format size in the same print tray compartment  255 . 
     In accordance with the present invention, as described above, an ink image set  110  comprising a plurality of ink images  170 - 190  are first formed before individual prints  240  are prepared and stacked. A delay time is therefore provided after the printing operation and the stacking operation. This delay time provides extra time for the ink images  80 ,  90 ,  170 - 190  to dry on the wide ink receiver  50 , which is beneficial for minimizing image artifacts related to insufficient drying. 
     Another advantage in accordance with the present invention is in the long printing pass length that can span across both the narrow ink receiver  49  and the wide ink receiver  50 . As it is well known in the art, a long printing pass increases the duty cycle of ink jet printing and thereby increasing the printing throughput. 
     FIGS. 5 and 8 show the receiver transport configuration when small-format ink mages are in the process of being printed on the narrow ink receiver  49 . The narrow receiver roll  56  is first transported to a printing position by the receiver transport mechanism  55  under the control of the control electronics  25 . The configuration of the transmission system  600  is shown in FIG.  8 . 
     An ink image  49  is first printed by the ink jet print heads  40 . The receiver registration plate  147  is moved up by the platen transport mechanism  165 . After the first receiver cutter  100  performs its cutting operation, an ink image  112  is formed on the receiver. The ink image  112  is transferred onto receiver transport shelf  145 . The upward positioned receiver registration plate  147  limits the movement of the ink image  112  in the direction of the first receiver path  60 . The cone-shaped rollers  150  are actuated by the platen transport mechanism  165  to move the ink image  112  along the second receiver path  160 . The cone-shaped rollers  150  drive the ink image  112  to be aligned to the receiver registration plate  147  during the movement along the second receiver path  160 . The ink image  112  is transported by the cone-shaped rollers  150  to a receiver cutter device  200 . 
     As the ink image  112  is moved through the receiver cutter device  200 , the receiver detector  210  detects the lead edge of the ink image  112 . The receiver detector sends signals to control electronics  25  which sends a receiver position signal further to computer  20 . The computer  20  calculates the border positions of the ink image  112 . If needed, the computer  20  then controls the control electronics  25  to actuate the second receiver cutter  220  to cut the borders of the ink image  112 . The waste or slug is dropped into a slug container  230 . In this way, separate prints  240  having ink images of a desired size are formed in response to a digital image file. The prints  240  are placed and stacked in a print tray  250 . 
     One advantage of the present invention is the reduction of receiver waste by optimally distributing ink images on both the narrow and wide ink receivers. FIG. 9 illustrates such receiver waste when ink images are formed only on a wide ink receiver  50 . For a specific example, the receiver width  59  can be 37″ for the wide receiver web  50 . A plurality of ink image sets  900 ,  910 ,  920 ,  930 , and  940  can be formed on the wide receiver web. As described above, an image border may exist between two adjacent ink image sets and the image border can be cut off as slugs by the first receiver cutter  100 . Each ink image set includes one or more ink images  905  and  943 . The ink images are in 4R size, that is, the print length  93  is 6″ and the print width  92  is 4″. An eighth inch image border  907  can also be provided between the neighboring ink images  905  in each ink image set  900  through  940 . The image borders  907  will be cut off by the second receiver cutter  220 , also as described above. For the receiver width  59  of 37″, there can be a maximum of 6 4″ ink images distributed across the first receiver path  60 . 
     In the exemplary configurations described above, there is a minimal amount of receiver waste (1″ out 37″ in an ink image set) when six 4R ink images  905  are printed in each ink set ( 900 - 930 ). In other words, receiver waste can be minimized when a print job requires the printing of a multiple of six ink images. Examples of these include 24 or 36 single or double 4R prints. Receiver waste is greatly increased, when a print job has a number of ink images not divisible by  6 . For example, as shown in FIG. 9, a 25 th  ink image needs to be formed on a fifth ink image set  940 . This 25 th  ink image can be an extra image the customer has shot on a 24-frame photographic film or an index print containing thumbnail images for a 24-frame photographic film. This situation results in a large unprinted receiver area  946 , as shown clearly in FIG.  9 . Principally, this unprinted receiver area  946  can be printed by the next print job. But in a microlab, the ink jet printing apparatus often receives one print job at one time. Receiver usage optimization is often not possible because a fast turn-around is often required for each customer. In summary, the unprinted receiver area  946  results in a large receiver waste. 
     FIG. 10 shows how receiver waste is minimized when ink images formed on the wide ink receiver  50  and the narrow ink receiver  49 . In addition to the wide receiver roll  57 , a narrow receiver roll  56  is provided. Still using the example described above, the narrow ink receiver  49  supplied from the narrow receiver roll  56  has a width of 6″ or slightly wider that is suitable for containing one 4R (4″×6″) ink image. With the narrow ink receiver, the extra ink images (ink image on the narrow receiver web  980 ) can now be printed on the narrow ink receiver. It is understood that the ink image on the narrow receiver web  980  can be chosen as one of the 25ink images to be printed so that when the ink images are transported along the second receiver path  160  and cut by the second receiver cutter  220 , the prints  240  can be stacked in an order desired by the customers. The large amount of receiver waste in the unprinted receiver area  946  (in FIG. 9) by using the wide ink receiver alone is now eliminated. 
     Furthermore, the ink image on the narrow receiver web  980  and the ink images  905  in the first to fourth ink image sets  900 - 930  are formed in a plurality of digital image  1000  by the computer  20  so that the images can be printed in the same printing pass on both the narrow ink receiver  49  and the wide ink receiver  50  simultaneously. As it is well known in the art, longer printing passes are also beneficial for increasing printing throughput. 
     In FIGS. 9 and 10, 4R (4″×6″) ink images and a particular receiver width are used to illustrate the receiver waste and how it can be minimized. It is understood, however, that the receiver waste generally exist for ink images in other formats such as 3.5″×5″ (3R), high definition TV (HDTV) (4″×7″), panorama (4×11.5″), A size (8.8″×11″). Likewise, the minimization of receiver waste can also be generalized in accordance to the present invention. Furthermore, a print job can have more than one format size in one (or a batch of) digital image file(s). The receiver configuration can be tailored to optimize the receiver usage at each format. For example, a 3R print job can be printed with a 5″ wide narrow receiver web and a wide receiver web. In addition, more than one narrow receiver webs can be provided in parallel to the wide ink receiver  50 . For example, one narrow receiver web for 3R format ink images and another for 4R format ink images. 
     FIG. 11 shows a flow chart of the operational steps for minimizing receiver waste in the ink jet printing apparatus in accordance with the present invention. In box  1110 , the digital image file(s) are input to the computer  20 . Next, in box  1120 , the computer  20  determines the receiver configuration such as the number of receiver webs loaded on the ink jet printing apparatus  10  and the width of each ink receiver. In some cases, a receiver web of different width may be loaded for the optimal receiver usage or other customer needs. As described above, more than one narrow ink receiver  49  may be available. 
     In box  1130 , a question is asked whether the receiver usage can be optimized over more than one print job? The answer is yes when more than one print jobs are requested at this time and when there is unprinted receiver area  946  in the last print job. The unprinted receiver area from the last print job is determined in box  1140 . Following box  1140  or if the answer to the question in box  1130  is NO, the number of ink image sets to be printed on the wide receiver web is calculated in box  1150 . These ink image sets will occupy the wide ink receiver in an efficient fashion, for example, the ink image sets  900 ,  910 ,  920  and  930  in FIG.  10 . As discussed above, ink images of different print lengths can be included in the ink image sets. Next, in box  1160 , the computer  20  calculates the number of ink images (e.g. the ink image on the narrow receiver web  980  in FIG. 10) to be printed on the narrow receiver web. In box  1170 , the computer  20  sequences all ink images to be printed on the narrow and the wide receiver webs in that print job. The desirable sequence of the ink images can be made according to the definitions in the digital image file. In box  1180 , the computer processes the digital images corresponding to these ink images according to the sequence to form a plurality of images  1000 . As described above, proper image borders are designed between ink images within an ink image set as well as between ink image sets. 
     In box  1190 , the ink images in the print job are printed by the ink jet print heads  40  under the control of the print head drive electronics  30  according to a plurality of digital images sent from the computer  20 . Finally, in box  2000 , the prints carrying these printed ink images are stacked in the desirable sequence in print tray compartments  255 . 
     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
     Parts List 
       10  ink jet printing apparatus 
       20  computer 
       21  film scanner 
       22  CD drive 
       25  control electronics 
       30  print head drive electronics 
       40  ink jet print heads 
       45  display panel 
       49  narrow ink receiver 
       50  wide ink receiver 
       55  receiver transport mechanism 
       56  narrow receiver roll 
       57  wide receiver roll 
       58  shaft 
       59  receiver width 
       60  first receiver path 
       65  print head transport mechanism 
       67  guiding rail 
       68  flexible connector 
       70  print head scanning direction 
       75  right frame housing 
       76  left frame housing 
       78  ink image 
       79  large format ink image 
       80  ink image 
       90  ink image 
       92  print width 
       93  print length 
     Parts List (con&#39;t) 
       100  first receiver cutter 
       105  first cutting direction 
       110  ink image set 
       112  ink image 
       145  receiver transport shelf 
       146  receiver transport surface 
       147  receiver registration plate 
       150  cone-shaped roller 
       160  second receiver path 
       165  platen transport mechanism 
       170  ink image 
       180  ink image 
       190  ink image 
       200  receiver cutter device 
       210  receiver detector 
       220  second receiver cutter 
       230  slug container 
       240  print 
       250  print tray 
       255  print tray compartment 
       600  transmission system 
       601  transmission housing 
       605  capstan roller 
       610  idler shaft 
       615  motor 
       620  motor shaft 
       625  capstan roller 
       630  driving gear 
       635  gear 
     Parts List (con&#39;t) 
       640  gear 
       645  gear 
       650  gear 
       655  output gear 
       660  output gear 
       665  teeth 
       900  first ink image set 
       905  ink images 
       907  image border 
       910  second ink image set 
       920  third ink image set 
       930  fourth ink image set 
       940  fifth ink image set 
       943  mismatched ink image 
       946  unprinted receiver area 
       980  ink image on the narrow receiver web 
       1000  a plurality of digital images 
       1110  Input digital image file(s) 
       1120  Determining or setting receiver configuration 
       1130  Can receiver usage be optimized over more than one print job? 
       1140  Determine the unprinted receiver area from the last print job 
       1150  Calculating the number of ink image sets to be printed on the wide receiver web 
       1160  Calculating the number of ink images to be printed on the narrow receiver web 
       1170  Sequence the ink images to be printed on the narrow and the wide receiver webs 
       1180  Processing the digital images according to the sequence to form a plurality of images 
     Parts List (con&#39;t) 
       1190  Printing ink images according to a plurality of digital images 
       2000  Stacking the ink image prints in a desirable sequence