Abstract: A copier for recording images of plural documents on recording sheets. The copier includes: a scanner for reading the images of the documents by photoelectrically converting the images so as to obtain image data corresponding to the images; a document feeder for sequentially feeding the documents to the scanner; a memory for storing the image data, including plural data compression/expansion circuits for compressing and expanding the image data, a selector for selecting one of the plural data compression/expansion circuits, and a memory member for storing the image data compressed by the selected one of the plural data compression/expansion circuits; a printer for forming images, corresponding to the selected image data from the memory, on the recording sheets; and a controller circuit for generating memory data overflow signals when a remaining area of the memory member is not more than a predetermined value.

Abstract: An image forming apparatus includes an image carrier for forming an image thereon; a sheet feeding device for feeding a recording sheet to the image carrier to transfer the image onto the recording sheet; a reversing device for reversing the recording sheet on one side of which the image has been transferred and then which has been fixed, at a conveyance path in the reversing device and for feeding the recording sheet onto the image carrier to form another image on a rear side of the recording sheet; a detection device provided between the conveyance path and the image carrier for optically detecting an amount of skew or an mount of shift of the recording sheet. The apparatus further includes controller for judging the amount of skew or the amount of shift to be malfunctional when the amount of skew or the amount of shift exceeds a predetermined value, and for modifying image forming conditions thereafter.

Abstract: An image recording apparatus, such as a copying machine and a printer. The image recording apparatus includes: a reading section for scanning an image on a document and generating image signals corresponding to the image; a memory for storing the image signals; an image formation processing section for forming an image on a transfer sheet according to the image signals; a sheet feeding section for holding the transfer sheet and feeding the transfer sheet to the image formation processing section; a sheet discharging section for discharging the transfer sheet outside the image recording apparatus; and a setting section for selecting one of a one-side copying mode, when only an image on one-side of the document is formed on one-side of the transfer sheet, and a two-side copying mode, when images on both sides of the document are formed on respective sides of the transfer sheet.

Abstract: An image recording apparatus includes a memory for storing an image information of each page; an image forming device for recording an image onto a recording sheet for each page on the basis of the image information in the memory; a recording sheet conveyor for conveying a recording sheet to the image forming device to record an image on one side thereof, and after that, conveying again the recording sheet to the image forming device to record an image on another side thereof, with no recording sheet being stacked during conveyance, and the recording sheet being conveyed along a specified conveyance path, and a predetermined maximum number of recording sheets can exist within the specified conveyance path.

Abstract: An image forming apparatus wherein a recording medium stored in a storage device is first detected by a detection device and the recording medium is abutted against a second paper feed roller, the second paper feed roller being driven by a controller for feeding the abutted recording medium to an image forming unit, at the timing at which the tip of an image in the image forming unit is in accord with the tip of the recording medium for each of the size of the recording medium.

Abstract: An image forming apparatus wherein a recording medium stored in a storage device is first detected by a detection device and the recording medium is abutted against a second paper feed roller, the second paper feed roller being driven by a controller for feeding the abutted recording medium to an image forming unit, at the timing at which the tip of an image in the image forming unit is in accord with the tip of the recording medium for each of the size of the recording medium.

Abstract: An image density reading apparatus in which an image of a document is irradiated by a light source and a density signal is generated from an image light reflected from the image. In the apparatus, there is an amplifier for amplifying a density signal on the basis of an amplifying gain and a signal processor for processing the amplified density signal in accordance with a predetermined processing algorithm to output a gain control signal. The amplifier is provided with a switch for changing a gain in response to the gain control signal.

Abstract: An image forming apparatus in which when a brake sensor detects a holding frame of exposure light source which moves in the backward direction, the movement of exposure light source is braked and reversed in the forward direction so that a density reference plate and a document are exposed by the exposure light source and patch image obtained by the exposure of the density reference plate is utilized for controlling the toner density. The duration of braking time which is started by turn-on of the brake sensor is previously set in accordance with the magnification of reproduction. The duration of braking time is increased as the magnification of reproduction is set greater.

Abstract: A temperature controller wherein breakage of a thermistor whose resistance decreases with increase in temperature of a member to be heated is detected by watching whether a voltage dependent upon the resistance of the thermistor is increased or not after a predetermined period of time. A heater for heating the member is turned off when the breakage of the thermistor is detected.

Abstract: The invention provides an image forming apparatus capable of performing an ordinary copy mode, whereby the entire surface of a document is scanned by an image reader to copy the entire surface on a copy sheet, and a serial page copy mode, whereby first and second half portions of the document are separately scanned to copy each half portion on a separate copy sheet. In the apparatus, copy sheets of different sizes are fed from a plurality of cassettes each storing a copy sheet of a predetermined size or a manual feed tray. There is provided a memory for memorizing a serial copy sheet size to be fed from the manual feed tray. When the serial page copy mode is selected in the manual feed mode, the image reader is controlled to separately scan the first and second half portions of the document on the basis of the serial copy sheet size.

Abstract: An aluminum oxynitride refractory of a sufficiently high nitrogen content is produced efficiently and inexpensively by a method which comprises mixing alumina of Bayer Process with aluminum dross and electrically fusing the resultant mixture in an electric furnace.