Optical scanning device, laser diode driver and image forming apparatus having shift register to receive a shift signal

A laser diode driver comprising:

• a plurality of light emission control terminals each connected with a corresponding one of N light emitting elements of a semiconductor laser, N being a natural number equal to or more than two;
• a detection signal receiving terminal configured to receive a detection signal output from an optical sensor of the semiconductor laser;
• and
• a shift register comprising:
• a plurality of output ports each configured to output a light emission signal for controlling light emission from a corresponding one of the N light emitting elements;
• and
• an input port configured to receive a shift signal, the shift register being configured to, each time receiving the shift signal via the input port, shift a specific output port from one output port to another in sequence among the plurality of output ports and output the light emission signal via the specific output port,
• wherein each of the plurality of light emission control terminals is configured to switch a state of the corresponding light emitting element between a light emitting state and a turned-off state, based on the light emission signal received from a corresponding one of the plurality of output ports of the shift register.

An image forming apparatus comprising:

• a photoconductive body:
• a controller;
• and
• a scanning unit connected with the controller via a signal line, the scanning unit comprising:
• a semiconductor laser comprising N light emitting elements, N being a natural number equal to or more than two;
• an optical system configured to convert light emitted by each of the N light emitting elements into a beam;
• a deflector configured to deflect the beam received through the optical system;
• and
• a shift register comprising:
• a plurality of output interfaces each configured to output a light emission signal for controlling light emission from a corresponding one of the N light emitting elements;
• and
• an input interface configured to receive a shift signal from the controller via the signal line, the shift register being configured to, each time receiving the shift signal from the controller via the input interface, shift a specific output interface from one output interface to another in sequence among the plurality of output interfaces and output the light emission signal via the specific output interface, thereby controlling light emission from each of the N light emitting elements.