Ricoh Company, Ltd.

Tetsuro Tatebe

Takashi Michiyoshi

An exposure device, which emits light according to a gray level of image data, includes plural light emitting element lines arranged at different positions in a sub scanning direction, a number of the light emitting element lines being a number of bits representing a number of gray levels. Each of the light emitting element lines includes plural light emitting elements arranged in a line in a direction parallel to a main scanning direction, the light emitting elements numbers of layers of organic electro-luminescence light emitting elements being the same. The numbers of layers of the organic electro-luminescence light emitting elements laminated in the light emitting element lines, which are arranged at different positions in the sub scanning direction, are different from each other.

Exposure device and image forming apparatus

A PWM signal generating circuit, printer, and PWM signal generating method are described. The PWM signal generating circuit includes: a single counter configured to count values expressed in N bits; and at least one arithmetic device configured to generate a PWM signal, each of the at least one arithmetic device including a pulse width data storage unit for storing N-bit pulse width data representing a pulse width of the PWM signal to be generated, and an adder for calculating a carry value from a most significant bit obtained when adding the count value and the pulse width data. A signal having a level corresponding to the carry value is output at every change in the count value so that the PWM signal having the pulse width of the pulse width data is generated.

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Osaka, Japan

Tetsuro Tatebe