Facsimile and static presentation processing – Static presentation processing – Position or velocity determined
Reexamination Certificate
1998-03-16
2001-10-30
Gabriel, Garcia (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Position or velocity determined
C358S001100
Reexamination Certificate
active
06310695
ABSTRACT:
BACKGROUND
The present invention relates to an electronic image registration system for a high-speed printer controller, and more particularly, to a dedicated hardware architecture for performing registration on an image in the form of a continuous stream of rasterized bit-map data. This registration is performed independently of page description language (“PDL”) decoding and image rendering operations performed by the printer controller's graphics processing units.
The printing industry has advanced to the point that printing capabilities are no longer limited by the print engine speeds, but rather by the amount of processing time required by the printer controllers. Furthermore, as the printer controllers move into the field of variable data printing, in which each page map shares a common background or “template”, and at least one set of image data bits changes for each page, the processing and dispatching times of such page-maps become increasingly significant. Therefore, for such printer controllers, it is imperative that the software-driven processing units on these printer controller boards have limited and specialized functions such that the PDL decoding, image processing and bit-map transport operations are performed as quickly and as efficiently as possible.
Therefore, on raster printer controller boards such as these, it is desirable to divide the controller architecture into a number of functional sections where each section is controlled by a dedicated microprocessor, operating in a pipeline fashion, and where each processing section is responsible for a specific functional operation of the raster printer controller.
High-speed printers utilizing these raster printer controllers can be configured to print variable image data on a predefined portion of a pre-printed form, i.e., printing customer addresses on a portion of a mass-mailing advertisement. As these forms are being printed, it is not uncommon that the printed images become misaligned with respect to the area in which they are to be printed on the form. Therefore, an image registration system is required to align or “register” the image with respect to this area on the form in real time. This misalignment of the image can be caused by circumstances such as the paper stretching or deforming, changes in the sizes of paper being used, etc.
One known method of registering the image with the pre-printed form is to mechanically shift the paper or mechanically shift the printing apparatus during the print job such that the image is aligned with the paper. Disadvantages with registering a print job in such a manner are that the mechanical registration can be complicated, imprecise and unreliable.
Another typical method for registering the image with the pre-printed form is to have the rendering units (the processing units which decode the PDL data and build the bit-map of the image from the decoded PDL data) on the printer controller render each image separately, incorporating the registration requirements in each rendering operation. A disadvantage with this method is that it significantly increases the complexity of the rendering operations and thus significantly slows the processing speeds of the rendering units, and in turn, of the printer controller.
Yet another known method for horizontally registering the image with the pre-printed form is to buffer a complete scan-line of the rendered bit-map data in memory and then shift the image as necessary. A disadvantage of this method is that it requires sufficient memory to hold an entire scan-line.
Thus, it is desirable to have a registration system which is performed electronically by the raster printer controller system; which is performed independently of the decoding and rendering operations of the controller board; which requires a significantly small amount of memory; and which is also substantially software independent, resulting in a very fast and reliable real-time registration operation.
SUMMARY OF THE INVENTION
The present invention is an electronic image registration system for a high-speed raster printer controller which comprises dedicated hardware for performing run-time registration, in both the horizontal and vertical directions, on a continuous stream of rasterized bit-map data generated by the rendering units of the raster printer controller. The registration takes place in hardware, between the rendering section of the controller and the print engine, thus allowing the registration to be performed in real-time without slowing the controller's processing speeds.
The dedicated run-time electronic-image registration hardware for the vertical registration of the image comprises a vertical holding register and a vertical counter. The vertical holding register is loaded by a microprocessor and indicates the magnitude of the vertical registration, which in turn indicates a length of delay in scan-line units before the start of the page-map's print cycle after seeing a “top-of-form” signal from the print engine.
The dedicated run-time electronic-image registration hardware for the horizontal registration of the image comprises a barrel-shifter, a data bus coupled to the input port of the barrel-shifter for transmitting the data stream to the barrel-shifter one block of scan-line data at a time, a history (spill-over) register coupled to the output of the barrel-shifter, and a logical adding device having a first addend input port coupled to the output port of the barrel-shifter and a second addend input port coupled to the output port of the history register.
The horizontal and vertical registration systems act upon the current value stored in the horizontal and vertical holding registers. These holding registers are accessible by the CPU via a CPU data bus. These holding registers can be updated by the CPU with new values anytime during run-time operations in response to, for example, an operator activating cursor keys on an operator input device. The operator may be activating the cursor keys on the operator input to align the printed images with respect to a pre-printed form during a production run. Alternatively the horizontal and vertical holding registers could be modified in response to any automated sensing means as is known in the art.
The value of the data in the horizontal holding register is preferably a two's complement binary number indicating the magnitude and direction of the horizontal movement of the image across the width of the printed page (or otherwise referred to as the horizontal registration). Therefore if this value is positive, the horizontal registration will occur in one direction, and if this value is negative, the horizontal registration will occur in the opposite direction.
The horizontal registration operation involves loading a present block of the scan-line data into the barrel-shifter, barrel-shifting the present block a number of bits corresponding to a pre-determined shift count which is derived from the value of the data in the horizontal holding register, isolating the present shifted block of bit-map data and the present spill-over block of bit-map data, transferring the present shifted block to one of the addend inputs of the adding device and transferring the present spill-over block to the history (spill-over) register. The transfer of the present spill-over block to the history register causes the history register to output a previous spill-over block to the other addend input of the adding device; the previous spill-over block being generated by the barrel-shifting and isolating operations performed on the previous block of scan-line data. Thus, the adding device adds the present shifted block to the previous spill-over block to create a present registered block of bit-map data (pixel shifted and aligned) which is sent to the fiber-optic output port for dispatch to the print engine.
The same operation is performed on the next block of scan-line data received by the registration device. Therefore, the next registered block will comprise the sum of this next shifted block of bit-map data
Gauthier Forrest P.
Jovic Dimitrije L.
Gabriel Garcia
Thompson Hine LLP
Varis Corporation
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