Abstract: An optical printer head has an array of lenses that project light emitted by an array of LEDs onto a charged photosensitive drum to form a latent image on the drum surface. A resin film adhered to the exposed surfaces of the lenses prevents chemical reaction between nitric acid, formed as a consequence of ozone produced during electric charging of the photosensitive drum, and alkali components on the surfaces of the lenses thereby preventing clouding of the lens surfaces and dimming of the projected light. The resin film has a thickness of 10 to 100 microns and may be formed of polyvinyl chloride, polyethylene terephthalate or polymethyl meta acrylate.

Abstract: An optical printer head that can, at a low cost, prevent the dimming of light at a lens, and an image forming apparatus that uses such an optical printer head are provided. A lens controls light, emitted by LEDs, that is used to irradiate a photosensitive drum. And since the lens is coated with a layer of resin, the resin prevents the occurrence of a chemical reaction between nitric acid, generated as a consequence of the production of ozone, and an alkali component on the surface of the lens, and prevents the dimming of light at the lens.