Patent ID: 9268250
Filing Date: 2016-02-23
CPC Classification: G03G

Claim Text:
1. An image forming apparatus for performing laser exposure to form a latent image on a photoconductor, the image forming apparatus comprising: a laser light source; a driving circuit configured to supply drive current to the laser light source in accordance with an image pulse signal depending on a dot pattern of the latent image; a current adjustment portion configured to increase or decrease an amount of bias current, the bias current being supplied as a part of the drive current to the laser light source; a pulse width expansion portion configured to expand a pulse width of the image pulse signal supplied to the driving circuit; a state detection portion configured to obtain state data indicating a state related to light emission start characteristics of the laser light source; and an adjustment control portion configured to set, based on the state data, a value of the bias current and an amount of expansion of the pulse width in such a manner that laser light emission occurs in a period of time having a length equal to a length of a pulse width of each pulse in the image pulse signal, wherein the adjustment control portion sets the value of the bias current and the amount of expansion of the pulse width in such a manner that the amount of expansion of the pulse width is greater than an amount of adjustment of a laser light emission time based on settings of the value of the bias current, and wherein the adjustment control portion sets, as the amount of expansion of the pulse width, a period of time that has a length of “m” times longer than a unit amount of expansion of the pulse width where “m” is an integer equal to or greater than 1, and further, has a greatest length among lengths equal to or smaller than a required period of time for the drive current supplied to the laser light source to increase from zero to a preset value of an amount of light emission, and sets the value of the bias current in a manner to compensate a difference between the amount of expansion and the required period of time.