Image forming apparatus with a sheet wrapping detection apparatus

Abstract

An image forming machine, such as a copier or a printer, for forming a toner image on a recording sheet includes a developer for forming a toner image on a photoreceptor, the photoreceptor holding the toner image on its surface; a transfer device for transferring the toner image onto the recording sheet; a light emitting device for irradiating a light beam onto the surface of the photoreceptor; a light receive for detecting a reflection of the light beam from the surface of the photoreceptor, and for generating a variable detection signal according to an amount of the reflection of the light beam; a first comparing circuit for comparing a value of the variable detection signal with a first predetermined threshold value, and for generating a first comparison signal; a first judgment circuit for determining whether or not a sheet wrapping jam of the recording sheet on the photoreceptor occurs according to the first comparison signal; a first memory for storing the value of the variable detection signal when the first judgment circuit determines that the sheet wrapping jam occurs; a first calculation circuit for calculating a second threshold value according to the value of the variable detection signal stored in the first memory; a second comparing circuit for comparing the value of the variable detection signal with the second threshold value, and for generating a second comparison signal; and a second judgment circuit for determining whether or not a sheet wrapping jam of the recording sheet on the photoreceptor is solved according to the second comparison signal.

Dependencies are inferred from the claim text.