Abstract: A two-drum copying machine having rotatable memory and transfer drums in which an optical path between an object point on the memory drum and an image point on the transfer drum is arranged obliquely with respect to the optical axis of a lens focusing light reflected from the object point onto the image point. A rotatable mirror is first set in a position to reflect light from an original to be copied onto the memory drum. After the memory drum has been rotated through one complete revolution and an image of the original formed thereon, a light source is turned on to project light directly onto the memory drum to illuminate the image. The mirror is then rotated out of the optical path to open the optical path through the lens between the object and image points. In a preferred embodiment, the sum of the angles of incidence and reflection of light at the object point is set to be twice the angle formed between the optical path and the optical axis of the lens.

Abstract: A copying machine of the type in which an original image is formed as a visible image on a first drum and the visible image from the first drum is transferred as a secondary original image to a second drum from which multiple copies are made. A single lens system is used both to transfer the image from the original document to the first drum and transfer repeatedly the image on the first drum to the second drum thereby greatly reducing the number of optical components required in the system.

Abstract: A copying apparatus and method in which a single image of an original is utilized to form plural copies without degradation of the copy quality. A single rotatable drum is provided which has first and second photosensitive surfaces formed thereon. The image of the original is first scanned in response to which a latent image is formed the first photosensitive surface. This image is developed to form a primary toner image. As the drum is rotated through 180.degree., the primary toner image is repeatedly transferred to the second photosensitive surface so as to form repeatedly, upon developing, secondary toner images which are transferred to recording sheets. The same optical system is utilized for illuminating the first photosensitive surface with an image of the original and for transferring the primary toner image onto the second photosensitive surface.

Abstract: A zoom lens for a copying system capable of both magnification and reduction of the image of an original to be copied in which the overall lens system may be miniaturized but yet various aberrations such as distortion are well corrected for. The lens includes a first lens group having a negative focal length and a second lens group having a positive focal length disposed in that order from the object side of the lens system. The distance between the first and second lens groups is variable while the distance between the object surface and the image surface is maintained constant. Movement of the first lens group serves primarily to maintain constant the distance between the object and image surfaces while the movement of the second lens group serves mainly to provide a variator effect.

Abstract: A variable magnification type copying system in which original can be duplicated with different magnification factors. Front and rear group lens systems are slidably mounted relative to one another upon front and rear frames which together make up a housing which is slidably mounted in the perpendicular direction upon a magnification unit frame. A stepping electric motor is mounted upon a plate which is rigidly coupled to the housing and slidably movable therewith. A pinion gear engaged with a pinion gear directly upon the output shaft of the motor is engaged with a rack of the rear frame. An L-shaped lever has a first end having a first cam follower held into abutment with a first cam rotatably mounted upon the output shaft of the motor and a second end connected to slidably move the front lens group by the front frame. A second cam is in abutment with a second cam follower upon the magnification unit to move the housing in the perpendicular direction.

Abstract: An achromatic objective lens having an aperture ratio of about 1:12 and a viewing angle of about .+-.1.degree. for use in an astronomical telescope is disclosed. The lens uses conventionally available optical materials matched to produce optimum compensation of various aberrations.

Abstract: A telephoto lens system comprises four lenses which are, in order from the object, a positive lens, a negative lens, a positive lens each having a stronger curvature surface directed to the object, and the final lens is a negative meniscus lens concave to the object. The inter-lens distances are progressively larger from the object side of the system.