Inner drum-type multibeam exposure method and inner drum exposure apparatus

An inner drum-type multibeam exposure method comprising the steps of:

• (a) controlling deflection, with light-deflecting means, of at least one of a plurality of light beams, which light beams are respectively independently modulated in accordance with image signals and emitted from a light source side;
• (b) causing the deflection-controlled light beam to be incident at scanning means via one of a reflection portion and a transmission portion which are provided at a sectional optical function member, and causing another of the light beams, which is not deflection-controlled by the light-deflecting means, to be incident at the scanning means via the other of the reflection portion and the transmission portion;
• and
• (c) with the scanning means, scanning for exposure on a recording medium, which is disposed at a support body of an inner drum, while a sub-scanning direction spacing between the plurality of light beams is maintained at a predetermined distance.

An inner drum exposure apparatus comprising:

• a plurality of optical systems at a light source side, for emitting light beams which are modulated in accordance with image signals;
• light-deflecting means disposed on an optical path of at least one of the plurality of light source side optical systems so as to control deflection of a light beam;
• a condensing lens which condenses the light beam that has been deflection-controlled by the light-deflecting means;
• a condensing lens which condenses a light beam emitted from the plurality of light source side optical systems other than the deflection-controlled light beam;
• a sectional optical function member, which is disposed such that a focusing position of the light beam that has been deflection-controlled by the light-polarizing means and a focusing position of the light beam emitted from the plurality of light source side optical systems which is not the deflection-controlled light beam correspond with a reflection portion and a transmission portion which are provided at different positions of the sectional optical function member, the sectional optical function member reflecting at least one of the light beams at the reflection portion and transmitting each other of the light beams through the transmission portion, for specifying an optical path of the light beam emitted from the plurality of light source side optical systems which is not the deflection-controlled light beam and an optical path of the deflection-controlled light beam so as to be incident at scanning means;
• and
• the scanning means, which, while maintaining a predetermined spacing in a sub-scanning direction between the plurality of light beams that have passed along optical paths specified by the sectional optical function member and are incident at the scanning means, focuses the plurality of light beams onto a recording medium disposed at a support body of an inner drum and performs scanning for exposure.

An inner drum exposure apparatus comprising:

• a plurality of optical systems at a light source side, for emitting light beams which are modulated in accordance with image signals;
• light-deflecting means disposed at the plurality of light source side optical systems so as to control deflection of the light beam of at least one of the optical systems;
• a condensing lens which condenses the light beam that has been deflection-controlled by the light-deflecting means;
• a condensing lens which condenses a light beam that has not been deflection-controlled by the light-deflecting means;
• scanning means for performing scanning for exposure;
• and
• a sectional optical function member including a reflection portion and a transmission portion, which sectional optical function member is structured such that the deflection-controlled and condensed light beam is incident at the scanning means via one of the reflection portion and the transmission portion, and the other light beam which has been condensed without being deflection-controlled by the light-deflecting means is incident at the scanning means via the other of the reflection portion and the transmission portion,
• wherein the scanning means, while maintaining a predetermined spacing in a sub-scanning direction between the light beams which are incident from the sectional optical function member, focuses the light beams onto a recording medium disposed at a support body of an inner drum and performs scanning for exposure.