Abstract: A method for memory write-back provides a memory access controller and then generates a write-back pattern in the memory access controller. The write-back pattern is then written back into a memory starting at a predetermined address location and continuing for a predetermined length of the addressing space of the memory.

Abstract: A printing apparatus comprises a memory storing a lookup table comprising tokens for converting image data having a first dots per inch (dpi) to image data having a second dpi. The printing apparatus comprises a processor configured to access the lookup table to convert an image having the first dpi to the second dpi, and a print engine configured to print the converted image at the second dpi.

Abstract: A printing apparatus comprises a processor comprising registers, and a memory configured to store image data. The processor is configured to load portions of the image data into the registers and perform toner explosion compensation on the portions of the image data loaded in the registers, excluding image data loaded in boundary positions in the registers.

Abstract: A printing system comprises a memory configured to store image data representing an image. The printing system comprises a processor configured to perform a first digital halftone process on a first portion of the image and a second digital halftone process on a second portion of the image.

Abstract: A method for image processing loads a cache line width column of image data into a data cache. The cache line width column of image data is then processed to enhance the image data; and the enhanced image data is then outputted.

Abstract: A method for image processing includes generating a pixel window of image data and determining whether the pixel window-is stable or unstable. Image enhancement values are then obtained from a look up table for stable windows when the window is stable, and image enhancement values are obtained from a look up table for unstable windows when the window is unstable. An enhanced target pixel value is then output according to the obtained look up table image enhancement value.

Abstract: An image processing method and device for processing multiple rows of pixels of an image simultaneously with a single instruction. The processing includes selecting a pixel window having a plurality of pixels of an image spanning across multiple rows and columns, building vertical and horizontal load registers to include the plurality of pixels of the selected pixel window, and simultaneously processing selected pixels of the plurality of pixels included in the vertical and horizontal load registers using a single instruction, wherein the vertical and horizontal load registers are shifted when the selected pixels are processed. Accordingly, a method and device for efficient processing of an image is provided.

Abstract: A laser printer for Braille that obviates the need for embossing mechanisms and specialized paper. A laser printer for Braille according to the present teachings increases an amount of a toner that adheres to an area of a paper that corresponds to the Braille element. The increased amount of toner yields a printed Braille element that may be read by touch.

Abstract: A laser printer includes a light source, a photosensitive drum, an oscillating mirror, a beam detector, and a control circuit. The light source shines a light beam towards the oscillating mirror, which reflects the light beam towards the photosensitive drum. The beam detector detects light reflected from the oscillating mirror. A reflected light beam hits the beam detector twice in each period of the oscillating mirror. The time interval between detected beams is used to determine the maximum mechanical deflection angle of the oscillating mirror. In an alternate embodiment, two beam detectors are used to detect light reflected from the oscillating mirror and determine its maximum mechanical deflection angle.

Abstract: A video controller includes a video block that connects to the print control engine and one laser driver. The video block includes a direct memory access (DMA) block, a video processor, a waveform generator including pattern and multiple pulse mode modulation, a frequency synthesizer, configuration registers, and a data bus. The frequency synthesizer connects to the waveform generator. The configuration registers connect to the DMA block, video processor and the waveform generator. The data bus, operative to carry bus control signals, connects the DMA block, video processor, waveform generator, and the configuration registers.

Abstract: A digital circuit generates very precise varying clock frequencies for applications that can tolerate a small degree of jitter but require exact longer term frequencies, e.g. a video clock for a laser printer. Some subpixel jitter is acceptable, but the overall pixel rate remains exact and consistent. In some applications, the jitter may be desirable to smear the EMI spectrum. For example, if the high frequency input clock is modulated, the edges of the video clock will also be modulated yet remain within the jitter and frequency specification.

Abstract: Reset circuitry for an integrated circuit is presented. An internal oscillator produces an oscillating signal upon power-up of the integrated circuit. The internal oscillator is not dependent on signals generated outside the integrated circuit. An electro-static discharge blocker circuit receives an external reset signal generated outside the integrated circuit. The electrostatic discharge blocker circuit utilizes the oscillating signal to perform electro-static discharge blocking for the external reset signal to produce an internal reset signal.

Abstract: The invention provides an architecture and method for implementing a programmable I/O interface. The primary function provides a generic reconfigurable interface for serial communications between a laser printer controller and the print mechanism. The design also supports vertical page synchronization (top of page detection).

Abstract: The video data is parallel processed allowing for extremely fast video processing or a greatly reduced clock requirement for the video processing circuit. In operation, each video channel reads from main memory. This allows each video channel to track the laser directly. The Parallel video processor receives non-columnar pixel data, such as rows. The videoprocessor may support printers of any width without significantly increasing the size of the system.

Abstract: A scanning control circuit includes a direct memory access controller (DMA), a video processor, and a video signal generator. A frequency synthesizer connects to the video signal generator. Configuration registers bidirectionally connect to the DMA, video processor, the video signal generator and the frequency synthesizer. A data bus electrically connects the DMA and the configuration registers.

Abstract: A digital circuit generates very precise clock frequencies for applications that can tolerate a small degree of jitter but require exact long term frequencies, e.g. a video clock for a laser printer. Some subpixel jitter is acceptable, but the overall pixel rate remains exact and consistent. In some applications, the jitter may be desirable to smear the EMI spectrum. For example, if the high frequency input clock is modulated, the edges of the video clock will also be modulated yet remain within the jitter and frequency specification.

Abstract: The software on the host machine examines a pixel, either alone or in relation to adjacent pixels. Based on the image data contained in the pixel or group of pixels, a multi-bit value is generated that can be used by the printing device to easily reproduce the necessary detail of the original pixel. The multi-bit value also contains print engine control parameters to handle items such as toner miser mode, toner explosion, edge roll off, etc. The multi-bit value can be generated algorithmically by using a lookup table or by some combination of these methods.

Abstract: A method and apparatus for printing data on a print medium is disclosed. The apparatus is configured to format print data to pixel data, the pixel data including pixel values; identify a grid of pixels having a predetermined pattern of pixel values; obtain predetermined pcode grid from memory for the identified grid of pixels; and send the predetermined pcode grid to controller circuit for printing.

Abstract: A method and apparatus for generating and controlling volume of a speaker of an appliance is disclosed. The appliance includes an IC chip connected to an amplifier subsystem. The IC chip includes a square-wave audio signal generator, a counter, a register, a comparator, and an AND gate. Theses components of the IC chip are used to generate modulated audio frequency square-wave signal. The modulated audio frequency square-wave signal having pulses, each pulse has a width determined by the volume control value. The modulated audio frequency square-wave signal is sent from the IC chip to the amplifier subsystem on a single connection. At the amplifier subsystem, the modulated audio frequency square-wave signal is integrated over, filtered, and amplified to drive a speaker to produce the desired sound. By adjusting the volume control value, the widths of the pulses, thus the volume of the produced sound can be controlled.

Abstract: A device for individually processing each color component of a serial analog signal from a color scanner. The device includes a multiple-channel-image-capture circuit comprising an analog front end/digitizer having a plurality of channels operable to process an analog-color signal with one channel for each color component of the analog-color signal, a register, and an analog-to-digital converter operable to output a digital signal responsive to the analog-color signal, and a controller operable to control the color component processing by the plurality of input channels such that each color component of a serial analog-color signal is individually processed. Each input channel of the analog front end/digitizer may include a programmable circuit operable to modify a color component of the color signal in response to a value stored in the register related to the color component.