Abstract: This invention discloses a developing apparatus wherein a brush of a developing agent is formed on a developing sleeve by a magnetic field of a permanent magnet disposed inside the developing sleeve, and at least the developing sleeve is rotated while the brush is kept in contact with a photosensitive body, thereby developing an electrostatic latent image formed on the photosensitive body. In this apparatus, an agitating member having magnetic ring portions which abut against the developing sleeve and an agitating portion for agitating the developing agent is pivotally disposed in a developing vessel to be parallel to the developing sleeve, and a rotation detecting unit for outputting a signal corresponding to a rotational speed of the agitating member and a residual amount detecting unit for detecting a residual amount of the developing agent in the developing vessel in accordance with an output from the rotation detecting unit are provided.

Abstract: A copying apparatus comprises a document glass, an automatic document feeder that is free to be opened and closed with respect to the document glass, a paper feeding means, means for storing image formed papers and an image forming means. The image forming means is operable in a special paper-passing mode that permits the transfer paper to be ejected into the storing means without having the image formed thereon. The copying apparatus is provided with means for detecting the open and close actions of the automatic document feeder so that an alarm can be issued to remind the operator of the document left on the document glass according to the signal issued by the detecting means after the operation of the image forming means has been completed, and the operation of the alarm means can be inhibited after the operation of the image forming means in said paper-passing mode has been completed.

Abstract: An image forming apparatus having a primary passage extending from a feeding unit which stores sheets up to a discharge tray which receives sheets with images formed thereon through an image forming unit which forms images on the sheet, and a secondary passage for returning each sheet which has been image-formed within the image forming unit to an upstream end of the primary passage from a downstream end thereof to form another image on the already image-formed side of the sheet or on the opposite side thereof. The secondary passage is formed so that in the event of jam or sheet therein, a portion of the secondary passage is exposed to the exterior by means of a guide plate capable of being opened and closed.

Abstract: The present invention relates to a copying machine constructed so as to make maintenance, and the replacement period for components in particular, readily understandable. The apparatus includes a first counter which counts the number of copies reproduced and a second counter which counts the use frequencies of the component whose use frequencies are not countable by said first counter.