Abstract: A method and a system for optically detecting an empty condition in a toner cartridge has a light reflector placed on an outside surface of a toner cartridge wall. A light source emits light directly or ultimately towards the light reflector and the reflected light is detected by a light detection device if the toner cartridge is sufficiently empty.

Abstract: In an image forming apparatus, a developing device is disposed adjacent to a belt-like photosensitive member. A rotary type developing device has a hollow cylindrical casing rotatable around a shaft having a central portion for rotation. The developing device includes a casing which is rotated in a predetermined direction, and four partitions which divide the casing to make four developing units which extend radially outward from the shaft. A toner storing section or hopper is provided on one side of the developing device, i.e., on a front side of the image forming apparatus, and a toner cartridge is detachable from a top of the hopper, and the toner cartridge is exchanged when an end signal of the toner is detected by a sensor in the casing. The toner hopper is filled by new toner from the toner cartridge, and the toner is carried by conveyor members, which control an amount of the toner in the casing, and a supply roller supplies the toner to a developing roller.

Abstract: An apparatus and method for detecting an empty condition of toner cartridges containing toner for copiers, fax machines, printers and the like is disclosed. The cartridges may be mounted to a rotary developing device. According to one embodiment, when a toner cartridge has been rotatably positioned to a developing position, an empty condition is detected by emitting light into the toner cartridge and detecting the light coming out of its bottom. To accomplish this detection, a light source and a light sensor are fixedly located near a bottom corner of the toner cartridge at the developing position. Light is emitted into the toner cartridge at a predetermined oblique angle with respect to a side wall of the toner cartridge. Light exits out from the bottom wall if a predetermined amount of toner does not exist in the toner cartridge. Due to the oblique angle, the distance between the light source and the light sensor is substantially reduced and provides an accurate measurement.

Abstract: A frequency converter is provided of which a frequency-dividing ratio is arbitrarily altered and retained after a power is turned off. The frequency converter has a programmable counter which outputs a signal having a desired frequency, a non-volatile memory for storing data for setting the frequency-dividing ratio and a control unit for controlling a writing operation of data stored into the non-volatile memory. The programmable counter, the non-volatile memory and the control unit are accommodated in a single package. The frequency converter may comprise a resonator and an oscillating circuit within the package so that the frequency converter can be treated as a single frequency generator such as a quartz-crystal oscillator.

Abstract: An image processing apparatus for image compression and decompression includes a smoothing part for smoothing image data of a reconstructed image by using a smoothing filter selected from among a plurality of smoothing filters having different smoothing effects, an averaging part for producing a set of values of averages of coefficients produced through discrete cosine transformation with respect to a plurality of blocks in the reconstructed image so that a distribution of the averages of the coefficients for a target block is generated, and a selection part for generating a signal to enable the smoothing part to select the smoothing filter by detecting whether or not peak values in the distribution of the averages of the coefficients, generated by the averaging part, appear substantially on a diagonal line of the target block passing a lowest-order position through a highest-order position of the target block.

Abstract: An automatic document feeder (ADF) used with an image processing apparatus, such as copier, has an original table for stacking thereon a plurality of originals to be scanned. A first and second receiving trays are each provided for receiving therein the originals. A first conveying mechanism is provided for conveying the originals from the feeding tray to an original supporting station of the ADF in order from the uppermost original and is able to reverse each of the originals upside down while conveying the same. A second conveying mechanism is provided for conveying a single-sided original from the station to the first receiving tray, without reversing the original upside down, after the scanning of one side of the original has been completed. A third conveying mechanism is provided for removing a double-sided original from the station and then returning the original to the station, while reversing the original upside down, after the scanning of one side of the original has been completed.