Patent Application
20130141757
The present invention is directed to duplex printing. In particular, the present invention is directed to methods and apparatuses for selectably controlling the order in which surfaces (the front and back sides of a duplex sheet) are sent to a multi-printhead duplex printer for printing thereby.
To overcome image quality issues in certain thermal duplex printers, the surface order delivery needs to vary in an irregular fashion, e.g., side A, side B, side B, side A. This irregular delivery sequence reduces the amount of contact between printed sheet surfaces and the drive roller. The drive roller typically comprises an aggressive texture for better feed control, however, it also compromises printable media surfaces and can deteriorate image quality. This method is inconsistent with the surface delivery mechanism from the Microsoft Windows driver, which always delivers rendered surfaces in a repeated and alternating “side A, side B” order (but which can start with either side). The central issue which needs to be resolved is how surfaces (the front and back sides of a duplex sheet) can be selectively delivered to a duplex printer that is capable of initially printing either side of a media sheet before printing the other side of the sheet. Certain software does not face this issue because both the front and back surfaces of a duplex sheet are individually available for selection prior to the delivery of the sheet print commands to the printer. Thus, there is a need in the art for a new printing architecture that implements a novel caching mechanism within the print driver. These changes are required to achieve the irregular surface delivery pattern that is required to obviate image quality issues.
A preferred embodiment of the present invention comprises a printing method including generating print image data for a first logical page of a duplex print job which logical page can be considered as the first page in an ordered sequence of pages in a final composition. A position of a receiver media in a printer is determined with respect to one of two printheads in the printer. A second logical page of the print job can be determined to be printed next in the printer before printing the first logical page of the print job, which is based on the step of determining where the receiver media is positioned in the printer. The first logical page of the print job then must be temporarily stored while generating print image data for the second logical page of the print job. The second logical page of the print job is then printed followed by printing the first logical page. The step of determining the position of the receiver media comprises determining which one of the printheads is capable of printing on the receiver media without retracting the receiver media. Retracting of the receiver media can be necessary if the media is positioned near one printhead and it is intentionally moved near the other printhead. If the print job comprises a plurality of even and odd numbered pages, then each of a plurality of pairs of the even numbered pages is printed consecutively, as well as the plurality of pairs of the odd numbered pages. The even numbered pages are printed using one of the two printheads and the odd numbered pages use the other printhead. The position of the receiver media can be determined by querying the printer which directs the printer to respond. A hard disk can be used for temporary storage of a printed page, which typically exists on a computer system connected to the printer. The first and second logical pages of the print job are printed on opposite sides of a sheet of receiver media.
Another preferred embodiment of the present invention comprises a method wherein image data is generated for a logical first page of a print job and for a logical second page of the print job. These are stored for later access. The position of a receiver media in a printer is determined with respect to one of two printheads. A print job is started in duplex format using either printhead, including printing the logical second page of the print job before printing the logical first page of the print job. The image data for the logical first page and the image data for the logical second page are each accessible for printing first on the printer. The position of the receiver media in the printer is based on which one of said two printheads is capable of directly printing on the receiver media without retraction of the receiver media. Only one of the printheads is used for printing the even numbered pages and the other for the odd numbered pages.
Another preferred embodiment of the present invention comprises a printing method wherein image data is generated for a logical first page of a print job and is stored. A position of a receiver media in a printer is determined with respect to one of two printheads. If a logical second page of the print job is required for starting the print job, then image data for the logical second page of a print job must be generated. Then the print job is started by printing the logical second page of the print job on a first side of print media, then accessing and printing the logical first page of the print job on a second side of the media. With a sufficient number of pages in the print job, alternating between printing a pair of logically numbered even pages and printing a pair of the logically numbered odd pages is undertaken. The same storage device can be used to store the logical second page of the print job and the logical first page of the print job. The printer can be a bidirectional printer such that it responds to printer queries sent from a connected computer system.
Another preferred embodiment of the present invention comprises a program storage device readable by a computer, tangibly embodying a non- transitory program of instructions executable by the computer to perform any of the method steps just described or various combinations of the method steps described above.
Other embodiments that are contemplated by the present invention include tangible, non-transitory computer program products, readable storage media, computer readable media, and program storage devices tangibly embodying or carrying a program of instructions, or storing computer programs, readable by machine or a processor, for having the machine or computer processor execute instructions or data structures stored thereon. Such tangible, non-transitory computer readable media can be any available media that can be accessed by a general purpose or special purpose computer. Such computer-readable media can comprise physical computer-readable media such as RAM, ROM, EEPROM, and other solid state electronic storage devices, and CD-ROM, DVD, or other optical storage media such as optical disk storage, optical tape, machine readable bar codes, or magnetic storage media such as magnetic disk storage (such as a floppy disk), magnetic tape, or other magnetic storage devices, for example. Any other media or physical device that can be used to carry or store software programs which can be accessed by a general purpose or special purpose computer are considered within the scope of the present invention.
These, and other, aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention and numerous specific details thereof, is given by way of illustration and not of limitation. For example, the summary descriptions above are not meant to describe individual separate embodiments whose elements are not interchangeable. In fact, many of the elements described as related to a particular embodiment can be used together with, and possibly interchanged with, elements of other described embodiments. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. The figures below are intended to be drawn neither to any precise scale with respect to relative size, angular relationship, or relative position nor to any combinational relationship with respect to interchangeability, substitution, or representation of an actual implementation.
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.
With reference to
In addition to the employing the Microsoft Universal Printer Driver architecture in modified printer driver embodiments described herein, a Microsoft Language Monitor 108, 208 has been implemented for each printer and is installed at the time of Printer Driver installation. The Language Monitor is responsible for (in most cases) building and sending USB command requests to, and for handling USB command responses from, the printer. Microsoft describes, in part, Language Monitors as follows
“Language Monitors are user-mode DLLs that serve two purposes:
They provide a full duplex communications path between the print spooler and bidirectional printers that are capable of providing software-accessible status information.
They add printer control information, such as commands defined by a printer job language, to the data stream.” (see http://msdn.microsoft.com/en-us/library/ff556450(VS.85).aspx)
Prior to sending each page of a document, a Page Info header structure is sent to the print spooler 204 indicating which page of the document is being sent as well as whether or not the page is simplex or duplex. This is a feature that was added to the print driver for the KODAK D4000 Duplex Photo Printer. This is later retrieved from the print spooler by the Language Monitor and is used to set up the printer appropriately. Interacting with software hooks provided by Microsoft to enable programmers to design custom plug-ins, the present Renderer Plug-In builds a print command and sends it to the print spooler. The Renderer Plug-In then applies the appropriate filters and image banding operations to the data created by the Renderer 202 and then spools out the rendered page (surface) data to the print spooler, three bytes (RGB) at a time, until the entire surface has been processed. The result of this process is that both the print command and a fully rendered, 8-bit RGB-interleaved page surface is transmitted to the print spooler as a rastered bit map. In parallel, the Language Monitor retrieves both the print command and associated image data and ultimately sends this to the bidirectional printer 206.
Rather than writing the entire rendered surface to the print spooler, a temporary file name will be constructed, and the rendered page surface data 103 will be written 102 to a temporary file 109, 209. The print command structure will be enhanced to include the name of the temporary file that was written. The result is that only the Page Info header and the enhanced command structure (see
Now including reference to
When a Page Info header is received and ready to be processed 104, and the printer is in a quiescent state, the printer will be queried as to the location of the paper position with respect to one of two thermal print heads in the printer 105. At that point, the Language Monitor will possess the knowledge of which surface (side) of the following sheet is required to be sent first. The surface to be sent first corresponds to the print head at which the paper is positioned. This avoids unnecessary retraction and repositioning of the media sheet with respect to the print heads and also avoids compromising the media surface by additional rolling contact with the textured feed roller.
a. Simplex sheet
If the Page Info header portion 351 indicates that the sheet is to be printed simplex, the Set Print Parameter Command will be built appropriately. This sets the parameter that signifies on which side the sheet should be printed.
Since the back side of a simplex sheet is laminated automatically, only data for a single surface data needs to be sent. Then the Print Command and the enhanced print command structure will be read from the print spooler. The Language Monitor will read the surface data from the temporary cached file 109, 209 and transmit the Print Command followed by the surface data to the printer. Once the commands and image data have been successfully consumed by the printer, the Language Monitor will delete the temporary file for that surface.
b. Duplex sheet
If the Page Info header portion 351 indicates that the sheet is to be printed duplex, the Set Print Parameter Command will be built appropriately (based upon the heuristic that determines which thermal head will be used and which media side must be printed upon next). There are now two possible scenarios:
Scenario 1: The next surface required is the next logical page of the document. The next logical page of the document is the next lowest page number (after the current page number) of the document in its completed printed form, which logical page number sequence might not reflect the print sequence in which the pages were printed. In this case, the print command and the enhanced print command structure will be read from the spooler. The Language Monitor will read the surface data from the temporary cached file and transmit the Set Print Parameter Command followed by the Print Command followed by the surface data to the printer 106. Once the commands and image data have been successfully consumed by the Printer, the Language Monitor will delete the temporary file for the surface. Then this process repeats with the second surface of the Duplex sheet.
Scenario 2: The next surface required is the page after the next logical page of the document. We refer to the next logical page as the “first page” and the page after that as the “second page.” In this case, the print command and the enhanced print command structure will be read from the spooler. Then, the Language Monitor caches this enhanced print command information (as a function separate from the page surface image data) and waits until the next page (second page) print command is available to be read from the Spooler, i.e. after the
Renderer finishes generating the second page image surface. Thus, image data for two surfaces are cached and the Language Monitor selects which is sent first to the printer. Then, the Set Print Parameter Command will be transmitted to the printer. The Language Monitor will read the second surface image data (second page) from the temporary file and then send the print command followed by the second surface image data to the printer 107. Then, the Language Monitor reads the temporary cached information (first page) and sends the print command followed by this first surface image data to the printer.
After the commands and image data have been successfully consumed by the printer, the Language Monitor will delete the temporary files for both surfaces of the duplex sheet.
Error detection and recovery
With this caching scheme, there are five new error conditions that need to be accounted for:
1. Rendering Plug-In, the temporary filename cannot be constructed.
2. Rendering Plug-In, the temporary file cannot be written. In either of these cases, the print spooler needs to be informed that the Rendering failed. The user will observe this as a failure to print their jobs.
3. Language Monitor, in the case of duplex where the second surface of the sheet is required to be printed first, but is never received. After the first surface is received, a timer will be initiated that will be cleared when the second surface arrives. If the timer expires prior to receiving the second surface, and new error will be generated and sent to the print spooler.
4. Language Monitor, temporary files cannot be read. If the files cannot be opened or if their image data is corrupted or incomplete, a new error will be generated and sent to the print spooler.
5. User cancellation of jobs. In the current architecture, the print spooler removes all of the rendered surfaces that are no longer required. That is because the rendered data co-exists with the page meta data within the print spooler. In the proposed architecture, this is not the case. To eliminate these older cached temporary files, the Language Monitor will examine the time stamps of the active jobs and delete any outdated previously rendered files from the temporary directory.
Output from host computer 10 is typically presented on a video display 52, which may be communicatively connected to the computer 10 via the display interface device 24. Internally, the computer 10 contains components such as CPU 14 and computer-accessible memories, such as read-only memory 16, random access memory 22, and a hard disk drive 20, which may retain some or all of the image data, page surface data, cached page data, commands, print documents, character data, and programming referred to herein, including a language monitor, print spooler, plug-ins, renderers, and other rendering engines. The phrase “computer-accessible memory” is intended to include any computer-accessible data storage device, whether volatile or nonvolatile, electronic, magnetic, optical, or otherwise, including but not limited to, floppy disks, hard disks, Compact Discs, DVDs, flash memories, such as USB compliant flash drives, for example, and ROMs, and RAMs. The CPU 14 communicates with other devices over a data bus 12. The CPU 14 executes software stored on, for example, hard disk drive 20 as described above. In addition to fixed media such as a hard disk drive 20, the host computer 10 may also contain computer-accessible memory drives for reading and writing data, such as page print image data, from and to removable computer-accessible memories. This may include a CD-RW drive 30 for reading and writing various CD media 42 as well as a DVD drive 32 for reading and writing to various DVD media 40. The printer 50, such as described herein, is a dye diffusion thermal transfer printer bidirectionally connected to a printer interface device 26 for communicating with processor 14 over data bus 12. However, the printer 50 should not be considered as limited only to this type. Printer 50 can record images on a tangible surface using a variety of known technologies including, but not limited to, conventional four color offset separation printing, other contact printing such as silk screening can be performed, or dry electrophotography, other thermal printing technology, drop on demand ink jet technology, and continuous inkjet technology, or any combination of the above is represented as printer 50. The connection between the thermal printer 50 and the printer interface device 26 serves as a two way communication channel between the printer and the host computer. The printer 50 includes a supply of receiver media, typically in rolled form, and preferably includes an exit tray for holding a plurality of printed receiver media sheets. Printer 50 typically incorporates memory sufficient to store print data for a plurality of pages of a print job. Additional information can be stored for each type and size of media, including a finish of media, for example. The printer preferably includes selectable printing options such as duplex and simplex printing. These selectable options can be controlled by user input to the computer system via the mouse 44 or keyboard 46 illustrated, and as confirmed by a convenient graphical user interface on video display 52. A digital scanner 6 or other image capture device such as a digitizing tablet or a camera can be communicatively connected to the computer 10 through, for example, the USB interface device 34 to transfer image from the scanner 6 to the computer's hard disk drive or other connected memory devices. Finally, the computer 10 can be communicatively connected to an external network 60 via a network connection device 18, thus allowing the computer to access digital objects and media assets from other computers, devices, or data-storage systems communicatively connected to the network.
A collection of print documents, and/or media assets can reside exclusively on the hard disk drive 20, compact disc 42, DVD 40, or on remote data storage devices, such as a networked hard drive accessible via the network 60, or on other local memory devices such as a thumb drive. A collection of digital objects and documents can also be distributed across any or all of these storage locations. A collection of digital objects and documents may be represented by a database that uniquely identifies individual digital objects (e.g., such as a print job) and their corresponding location(s).
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
U.S. patent application Ser. No. 13/______, entitled “Printer Driver Caching Architecture” filed concurrently herewith is assigned to the same assignee hereof, Eastman Kodak Company of Rochester, NY, and contains subject matter related, in certain respect, to the subject matter of the present application. The above-identified patent application is incorporated herein by reference in its entirety. Reference is made to commonly assigned, co-pending U.S. patent applications: Ser. No. 13/300,183 filed Nov. 18, 2011, entitled “System For Maintaining Proper Page Sequence While Reducing Printer Artifacts”; Ser. No. 13/300,251 filed Nov. 18, 2011, entitled “Printing Method For Maintaining Proper Page Sequence While Reducing Printer Artifacts”; Ser. No. 13/300,282 filed Nov. 18, 2011, entitled “Method For Maintaining Proper Page Sequence While Reducing Printer Artifacts”; Ser. No. 13/300,313 filed Nov. 18, 2011, entitled “Printing System For Maintaining Proper Page Sequence While Reducing Printer Artifacts”; the disclosures of which are incorporated herein by reference in their entireties.
