Patent Application
20090185213
The present disclosure relates to digital printing and particularly printing on cut sheets by electrostatic or xerographic processes and more particularly to such printing where it is required within a single job or among multiple jobs to print the page images on different sheet sizes. Such complex printing is available on recent digital print engines having multiple sheet feeders and digital front ends (DFE) capable of processing the page images of the desired different sizes.
Digital print engines of the electrostatic or xerographic type commonly have the page images processed on an endless photoreceptor belt formed of a single piece seamed to provide an endless loop. The endless photoreceptor belt is then typically driven over a pair of spaced rollers to provide a moving flat surface for transferring the page images to the individual media sheets. Typically, the length of the seamed belt is selected so there is maximum usage of the belt when printing the most likely sized images, for example maximizing belt usage for A4 sized images.
In such a print engine, the number of sheets of a given size which may be loaded onto the endless belt is thus a function of the length of the belt minus the width of the belt seam and the dimensions of the individual developed images to be placed on the belt. Where print jobs, such as multiple jobs or a single job employing sheets of a different size are executed, the media sheets of different sizes are thus intermixed on the flat surface of the belt during printing. Because of the different dimensions of the sheets of different sizes, the entire surface of the belt may not be utilized. Thus, it has been desired to provide a way or means of maximizing the usage of the photoreceptor belt in a digital print engine and yet maintain the flexibility of concurrent printing of page images employing different sheet sizes.
The present disclosure addresses the above described problem and provides a method of scheduling the feeding of sheets into a digital print engine for placement on a photoreceptor such as a photoreceptor belt in a manner which maximizes the usage of the photoreceptor belt for the image sizes employed in the print job. One version of the method addresses the print job situation in circumstances where multiple jobs are printed concurrently by feeding sheets of different sizes into the print engine from the feeders and intermixing the page images on the photoreceptor belt for concurrent printing of multiple jobs requiring different image and sheet sizes. A second version of the method addresses the type of print job having a single document employing page images requiring different sizes of media sheets for printing of the document and thus feeding of different size sheets into the print engine and intermixing; and, images of different sizes are concurrently placed on the photoreceptor belt. The method of the present disclosure continuously inquires as to whether a different combination of page images of different sizes that may be scheduled on the photoreceptor belt in order to maximize the usage thereof and includes any new jobs entered into the user job request during the printing process.
Referring to
Referring to the lower view of
Referring to
If the determination at step 30 is negative, the system again proceeds to step 26 to choose a single print job.
However, if the determination at step 30 is affirmative, the system proceeds to step 32 and inquiries if there are any new print jobs. If the determination at step 32 is affirmative, the system recycles to step 22. The determination at step 32 is also made if a single print job is chosen at step 26, and if the determination at step 22 has been found to be negative.
From step 32, the system proceeds to step 34 and queries whether there are enough output stations. If the answer in step 34 is affirmative, the system proceeds to step 36 and prints. However, if the determination at step 34 is negative, the system returns to step 26.
Referring to
If the inquiry at step 46 is answered in the negative, the system proceeds to inquire at step 48 as to whether there is a sheet buffer; and, if not, the system proceeds as if the determination at step 46 were affirmative and at step 50 feeds pages with the plural sheet sizes to the print engine. However, if the determination at step 48 is affirmative, the system proceeds to step 52 and feeds the pages with plural sheets sizes to the print engine to maximize belt usage by using the sheet buffer to hold sheets that are out of order. The system then proceeds to step 54 to merge the sheets in the appropriate order and then to step 56 to output the sheets of the document sequentially to an output station. The system proceeds from step 50 also to step 56 to output the sheets appropriately.
The present disclosure thus describes a unique and novel method for enabling a digital print engine of the type having an endless photoreceptor belt to print jobs which require print sheet media of different sizes, either within a single document or from multiple print jobs requiring sheets of different sizes. The page images are intermixed on the flat portion of the photoreceptor belt if intermixing will maximize the belt usage. If intermixing is employed, the print sheets are subsequently arranged in the proper combinations or order for outputting from the print engine to an output station. The disclosure thus describes a method which maximizes the usage of the photoreceptor belt irrespective of the dimensions of the sheets of different sizes by mixing the page images where such mixing would result in greater utilization of the surface of the photoreceptor belt.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
