Abstract: An image forming apparatus includes an image bearing member; a charging member for electrically charging the image bearing member; developing means for developing with a developer an electrostatic latent image formed on the image bearing member, the developing means having a developer carrying member for carrying the developer, wherein a gap is formed between the developer carrying member and the image bearing member; bias voltage applying means for applying a bias voltage to the developer carrying member, wherein the bias applying means applies an AC bias when the electrostatic latent image is developed, wherein the developing means is capable of collecting the developer fro the image bearing member, and an amplitude of an AC bias voltage applied to the developer carrying member by the bias applying means when the the developer is collected, is larger than that when the the electrostatic latent image is developed.

Abstract: An image forming apparatus including a movable image bearing member, a charging member disposed opposed to the image bearing member, a transfer member for transferring a toner image from the image bearing member onto a recording material, and potential control means far changing a potential gradient on the image bearing member at a position corresponding to an end of the recording material in a direction opposite from a charge polarity of the toner with respect to a direction opposite from a movement direction of the image bearing member.

Abstract: An image forming apparatus has an image forming unit and a film-heat-type fuser over which a sheet with an unfixed toner image passes and on which are positioned a first temperature-measuring device centered on the fuser so that a sheet always passes over that device and a second temperature measuring device disposed away from the center so that large sheets will pass over the second temperature measuring device and small sheets will not pass over the device when being conveyed correctly. The device also has a temperature control mechanism, a sheet size detector and throughput control, so that the throughput control changes throughput when the sheet size detector determines that a small sheet is being conveyed and the difference between the temperatures of the first and second temperature measuring devices is less than a predetermined value as the sheet passes over the fuser.

Abstract: An image forming apparatus includes an image bearing member; a charging member for electrically charging the image bearing member; developing means for developing with a developer an electrostatic latent image formed on the image bearing member, the developing means having a developer carrying member for carrying the developer, wherein a gap is formed between the developer carrying member and the image bearing member; bias voltage applying means for applying a bias voltage to the developer carrying member, wherein the bias applying means applies an AC bias when the electrostatic latent image is developed, wherein the developing means is capable of collecting the developer fro the image bearing member, and an amplitude of an AC bias voltage applied to the developer carrying member by the bias applying means when the the developer is collected, is larger than that when the the electrostatic latent image is developed.

Abstract: An image forming apparatus including a movable image bearing member, a charging member disposed opposed to the image bearing member, a transfer member for transferring a toner image from the image bearing member onto a recording material, and potential control means far changing a potential gradient on the image bearing member at a position corresponding to an end of the recording material in a direction opposite from a charge polarity of the toner with respect to a direction opposite from a movement direction of the image bearing member.

Abstract: The present invention provides an image forming apparatus, which has a roller-shaped image bearing member bearing a toner image thereon, and a transferring roller pressure-contacted with the image bearing member for transferring the toner image on the image bearing member to a transferring material, a radius of the transferring roller being 12 mm or less, wherein r/R<0.4 where r is the radius of the transferring roller, and R is the radius of the image bearing member.

Abstract: An image forming apparatus has an image forming unit and a film-heat-type fuser over which a sheet with an unfixed toner image passes and on which are positioned a first temperature-measuring device centered on the fuser so that a sheet always passes over that device and a second temperature measuring device disposed away from the center so that large sheets will pass over the second temperature measuring device and small sheets will not pass over the device when being conveyed correctly. The device also has a temperature control mechanism, a sheet size detector and throughput control, so that the throughput control changes throughput when the sheet size detector determines that a small sheet is being conveyed and the difference between the temperatures of the first and second temperature measuring devices is less than a predetermined value as the sheet passes over the fuser.

Abstract: A semiconductor laser is caused to emit laser light continuously on a plurality of scanning lines prior to image formation in a laser printer. An electric current to be applied is controlled so that the detected light quantity from the semiconductor laser becomes equal to the desired light quantity. The light quantity detected during pulsed emission with the applied current is used as the desired light quantity for APC which is performed at a space between sheets when a non-image area is scanned. Alternatively, laser light is emitted on a plurality of lines before the start of printing when printing of multiple pages is to be performed in a laser beam printer, to perform light quantity control. Then, laser light is emitted during scanning of a nonimage area between pages, to perform light quantity control. When light quantity control is performed between sheets, a value obtained by correcting an error between the quantities of light in both types of light quantity control is set as the desired light quantity.