Abstract: A device for measuring a luminance of a fluorescent screen of a cathode ray tube includes a photoelectric conversion device for receiving light from the fluorescent screen and converting the light to electrical energy, an integral device for integrating the electrical energy, a measurement device for measuring the glowing interval time of the cathode ray tube, and a control device for controlling the integral device so as to integrate the electric energy for a general integral time corresponding to the interval time. Also, this device has a calculation device for calculating an offset integrated electrical energy corresponding to a bias component of the photoelectric conversion device, another calculation device for calculating a true integrated electrical energy by subtracting the offset integrated electrical energy from the measured general integrated electrical energy.

Abstract: A sheet feed arrangement is provided in an image forming apparatus such as a printer or the like and is comprised of a sheet cassette for accommodating a plurality of sheet materials, a feed roller assembly disposed above the sheet cassette for feeding the sheet materials sheet by sheet by contacting with an upper surface of a topmost sheet of the sheet materials accommodated in the sheet cassette, and a tiltable guide plate disposed downstream from the feed roller assembly in a direction of feed of the sheet materials for guiding the sheet materials. The guide member can tilt together with the feed roller assembly so that an end portion of the guide member may be introduced in or removed from an inner end portion of the sheet cassette. The sheet feed arrangement is further comprised of a sheet lifting mechanism disposed below the sheet cassette for listing end portions of the sheet materials when the sheet materials are fed from the sheet cassette.

Abstract: A camera system being comprised of a camera and an external device is disclosed. The external device is detachably mounted on the camera which memorizes a program or data necessary for executing a program therein.When the external device is mounted on the camera, they are connected electrically with each other and communicate therebetween in order to read a program or data memorized in the external device into a memory means provided in the camera. The camera is controlled according to the program designated by the external device.

Abstract: The present invention relates to a copying apparatus capable of executing various copying operations. The copying apparatus has a first key for designating a format of an original document to be copied and a second key for designating a format of a copy to be formed and forms the image of the original document on a copy sheet in the designated format.