Abstract: A computer-implemented method of communicating message data in a frame of data includes transmitting the frame of data across a communication channel. The frame of data includes the message data, a first 8-bit digital control word, and a second 8-bit digital control word. Each control word has a unique bit pattern and is associated with a different time interval that individually indicates where or when the message data begins or began in the frame of data relative to the time interval's associated control word. At least one of the control words and other data are received. At least some of the other data are identified as the message data based upon receipt of at least one of the control words. Only one of the control words needs to be received to identify the message data from the other data.

Abstract: A method and system to improve the retention of synchronization between the transmitter and receiver of image data across a communication channel. If the control character designating the end of the line of data is corrupted, the receiving system will not recognize that the line of data has ended and will continue as if data is still being received. The corruption of a single bit in the control character will cause the receiver to misinterpret the end of line control word. Since the receiving logic does not realize the transmitter is no longer sending data, erroneous data will be stored in the storage elements. By using an alternate control character as an additional end of line indicator, the receiver will terminate the line of data and will wait for the next start of line control character from the transmitter. Synchronization between the transmitter and receiver across the communication channel is thus maintained.

Abstract: A computer-implemented method of communicating message data in a frame of data includes transmitting the frame of data across a communication channel. The frame of data includes the message data, a first 8-bit digital control word, and a second 8-bit digital control word. Each control word has a unique bit pattern and is associated with a different time interval that individually indicates where or when the message data begins or began in the frame of data relative to the time interval's associated control word. At least one of the control words and other data are received. At least some of the other data are identified as the message data based upon receipt of at least one of the control words. Only one of the control words needs to be received to identify the message data from the other data.

Abstract: A method and apparatus for the transmission of multiple control characters of the same type to a receiver to improve the retention of transmitter to receiver synchronization in a noisy environment having receiver code that is less complex and does not require an increase in the bandwidth of the system since the control codes are already utilized to initiate other functions. Detection of any of the control characters of the same type by the receiver allows the receiver to maintain proper synchronization. The receiver will detect these control signals and anticipate the occurrence of an event within a predetermined time period.

Abstract: A method and apparatus for transmitting and receiving image data and control characters across an interface that is subject to noise for output to a printer. The image data and the control characters are transmitted across the interface to a receiver device. A determination is made as to whether or not a line of image data has been sufficiently transferred to the receiver device and, if the current line of image data has not been sufficiently transferred, there is provided for output to the printer a prior sufficiently received line of image data in replacement of the current line of image data so that the prior line of image data is printed at least twice in succession.

Abstract: A driver IC (60) for a printhead includes a first set of data side input/output pads (62) and a second set of data side input/output pads (63). The driver IC further includes circuitry (100) that can select that data is to be input at the first set of pads and output at the second set of pads.

Abstract: A printhead with a variable exposure width having a plurality of exposure elements defining a given exposure width. A plurality of driver ICs are coupled to the exposure elements, each driver IC including a plurality of registers. A data bus is coupled to the plurality of driver ICs. Circuitry is provided in a first driver IC of the plurality of driver ICs for having data received from the data bus bypass the plurality of registers in the first driver IC to disable unused exposure elements of the plurality of exposure elements, whereby the exposure width can be varied from the given width, and data loading bandwidth is minimized.

Abstract: A method and apparatus for the transmission of multiple control characters of the same type to a receiver to improve the retention of transmitter to receiver synchronization in a noisy environment having receiver code that is less complex and does not require an increase in the bandwidth of the system since the control codes are already utilized to initiate other functions. Detection of any of the control characters of the same type by the receiver allows the receiver to maintain proper synchronization. The receiver will detect these control signals and anticipate the occurrence of an event within a predetermined time period.

Abstract: A product and process for an LED printhead used in electrophotographic printing that generates an exposure clock on the printhead for the LEDs. The present invention provides a high-speed interface that transmits print data that has been modified, or corrected, using the corresponding unique printhead brightness data as the base reference source data to the printhead boards. The corrected print data is then applied to the LED drivers that expose each LED simultaneously and uniquely. A non-linear clock is applied to the LED drivers as the reference clock to create the unique LED on time circuit. An Exposure RAM stores the data as parallel 8-bit data. A LATCH code received at an ASIC converts the Exposure RAM data into a serial bit stream. The preferred embodiment employs a 60 MHz clock, however, it should be readily apparent that numerous other clocking speeds can be employed.

Abstract: Increasing the linearity of elements within a printhead by applying a coarse electronic adjustment to rearrange the electronic printing of data into the proper pixel line and then applying a fine electronic adjustment to reduce the bow error to fraction of a pixel line. Delays of exposure control signals are used by the fine electronic adjustment to correct linearity by a fraction of a pixel line. The delays can be repeated to multiply the number of delays available and increase the linearity resolution. The delays can also be averaged between odd and even rows of elements to increase apparent resolution.

Abstract: The invention adjusts the calibration of each light emitting element, such as a light emitting diode (LED) by storing data representative of the difference between a linear or non-linear characteristic of the LED. In a printer or copier, a print engine uses LEDs to form a latent image on a photosensitive member. A linear regression identifies the differences between the slope of the individual LED and the average LED. A further, non-linear regression identifies the curvature of the individual LEDs. The differences in linear slope and/or curvature are stored and used to correct the calibration of each LED when the LED is recalibrated during operation and in response to a global calibration signal, GREF.

Abstract: A method and apparatus for the transmission of multiple control characters of the same type to a receiver to improve the retention of transmitter to receiver synchronization in a noisy environment having receiver code that is less complex and does not require an increase in the bandwidth of the system since the control codes are already utilized to initiate other functions. Detection of any of the control characters of the same type by the receiver allows the receiver to maintain proper synchronization. The receiver will detect these control signals and anticipate the occurrence of an event within a predetermined time period.

Abstract: A method and apparatus for increasing the linearity of elements within a printhead by applying a coarse electronic adjustment to rearrange the electronic printing of data into the proper pixel line and then applying a fine electronic adjustment to reduce the bow error to fraction of a pixel line. Delays of exposure control signals are used by the fine electronic adjustment to correct linearity by a fraction of a pixel line. The delays can be repeated to multiply the number of delays available and increase the linearity resolution. The delays can also be averaged between odd and even rows of elements to increase apparent resolution. The first embodiment employs digital circuitry to provide the fine adjustment of pixel data that is partially located on the interface board and partially located on the printhead substrate. This reduces the amount of circuitry placed within the ASICs on the printhead substrate.

Abstract: A product and process for an LED printhead used in electrophotographic printing that generates an exposure clock on the printhead for the LEDs. The present invention provides a high-speed interface that transmits print data that has been modified, or corrected, using the corresponding unique printhead brightness data as the base reference source data to the printhead boards. The corrected print data is then applied to the LED drivers that expose each LED simultaneously and uniquely. A non-linear clock is applied to the LED drivers as the reference clock to create the unique LED on time circuit. An Exposure RAM stores the data as parallel 8-bit data. A LATCH code received at an ASIC converts the Exposure RAM data into a serial bit stream. The preferred embodiment employs a 60 MHz clock, however, it should be readily apparent that numerous other clocking speeds can be employed.

Abstract: An operatory light fixture having a touchless switch operatively connected to a lamp disclosed. The touchless switch is constructed to detect a user's hand when positioned in a command location relative to the touchless switch and to respond thereto by operating the lamp. In a preferred embodiment, the touchless switch is an active infrared-type switch, comprising means for emitting infrared light toward a command location, means for detecting infrared light reflected from an object such as a hand which is positioned at or near the command location, and relay means responsively connected to the detection means and operatively connected to the lamp. In another preferred embodiment, the touchless switch includes means for discriminating a true signal produced by placement of an object such as a user's hand at the command location, from randomly occurring fluctuations in light intensity in the operatory environment.