Light scanning apparatus and image forming apparatus

A light scanning apparatus comprising:

• a deflector configured to deflect a light flux to scan a scanned surface;
• and
• an imaging optical element including an optical surface and configured to guide the light flux from the deflector to the scanned surface,
• wherein a first cross section is a section including a first deflection point on the deflector and being perpendicular to an optical axis of the imaging optical element, and a first marginal ray is a ray on a side closer to the first deflection point in the first cross section, the first marginal ray being included in an on-axis light flux reflected by the optical surface after being deflected at the first deflection point,
• wherein the light scanning apparatus is configured to cause the first marginal ray to travel toward a position spaced apart from the first deflection point in a sub-scanning direction by 4 mm or more in the first cross section, and
• wherein a width of the on-axis light flux on the first cross section in the sub-scanning direction is smaller than a width of the on-axis light flux on the optical surface in the sub-scanning direction.