Image forming apparatus with conveyance and exposure control

An image forming apparatus comprising:

• a laser unit for exposing an image bearing member according to image information to form a latent image on said image bearing member;
• a conveying roller for conveying a sheet to a transferring portion;
• and
• a top sensor for detecting the sheet conveyed by said conveying roller, which is disposed between said transferring portion and said conveying roller;
• and
• a judging device for judging whether or not it is possible to start exposure by said laser unit before a leading edge of the sheet conveyed by said conveying roller reaches said top sensor after the leading edge of the sheet passes through said conveying roller;
• and
• a control device for controlling so that the sheet conveyed by said conveying roller is stopped at a judging position between said conveying roller and said top sensor until it is determined that it is possible to start exposure by said laser unit,
• wherein said conveying roller again conveys the sheet stopped at the judging position, based on the judgment of the judging device, and said laser unit starts to expose the latent image on said image bearing member based on a detection of the sheet conveyed from said judging position, by said top sensor.

An image forming apparatus comprising:

• exposing means for exposing an image bearing member according to image information to form a latent image on said image bearing member;
• conveying means for conveying a sheet to a transferring portion;
• and
• sheet detecting means for detecting the sheet conveyed by said conveying means, which is disposed between said transferring portion and said conveying means;
• and
• control means for judging whether or not it is possible to start exposure by said exposing means before a leading edge of the sheet conveyed by said conveying means reaches said sheet detecting means after the leading edge of the sheet passes through said conveying means and for controlling said conveying means to temporarily stop the sheet at a judging position, if it is not possible to start exposure by said exposing means when the leading edge of the sheet conveyed by said conveying means reaches said judging position, and to again convey the stopped sheet when exposure is started, and for controlling said conveying means to continue to convey the sheet without stopping it if it is already possible to start exposure by said exposing means when the leading edge of the sheet conveyed by said conveying means reaches said judging position.