Patent ID: 6121994
Filing Date: 2000-09-19
Classification: B41J,G06K

Abstract:
An image forming apparatus comprising:(a) a photosensitive member;(b) exposure means comprising a light emitting element array which has a plurality of light emitting elements provided in the main scanning direction to the moving direction of the photosensitive member, a switching element array having a plurality of switching elements arranged so that a switching element is connected to each of said light emitting elements, a first group of leads, dividing said switching element array into a first group made of the switching elements for a first order and a second group made of the switching elements for a second order, the first group of leads made of a first gate line for the first order and a second gate line for the second order such that a plurality of switching elements in one switching element group are connected for every one divided switching element group, a second group of leads, connecting said switching elements of the first gate line and the second gate line to each other and dividing said switching element array into the first group and the second group made of the switching elements for the first order and the switching elements for the second order, respectively, the second group of leads made of a plurality of source lines commonly connected to a source terminal of a plurality of switching elements in one switching element group for every divided one switching element, a capacitor which charges electrical signals from said second group of leads via said switching elements and a simultaneous light emitting circuit for causing light to emit from said light emitting array simultaneously, thereby causing to discharge said capacitor simultaneously, said exposure means for executing exposure to said photosensitive member by the simultaneous light emission from said light emitting element array; and(c) drive means for applying a plurality of scan signals for a first time to said first group of leads in order and then to gate terminals of switching elements on the gate line to which the scan signals for each of said first group of leads is in an ON state, causing to charge the capacitor with voltage signals of a first polarity corresponding to image information from the second group of leads in this ON state period and to operate said simultaneous light emitting circuit in order to discharge said capacitor simultaneously, and successively for applying the scan signals for a second time to said first group of leads in order and then to the gate terminals of switching elements on the gate line to which the scan signals for each of said first group of leads is in the ON state, causing to charge a capacitor with voltage signals of a second polarity from the second group of leads in this ON state period and to operate said simultaneous light emitting circuit in order to discharge said capacitor simultaneously.