Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorKohei Koshida
Life of this patent
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Abstract
An image forming apparatus includes a plurality of loop detecting sensors which detect various levels of loops formed on a recording material; and a controlling device which selects a specific one out of the loop sensors in accordance with information on the recording material, and then, switches a conveyance speed of a fixing roller pair in response to a detection signal output from the specific sensor, so as to control in such a manner as to keep the loop of the recording material within a constant range, the controlling device selecting the loop detecting sensor for detecting a loop of a level in accordance with the information on the recording material, so as to perform a loop keeping control for the recording material in response to the detection signal output from the selected loop detecting sensor.
Claims12
An image forming apparatus comprising:
- a transfer portion which transfers a unfixed image borne by an image bearing member onto a recording material;
- a fixing device which fixes the unfixed image transferred at the transfer portion onto a recording material;
- a controlling device which controls a recording material conveyance speed of the fixing device so as to form a loop of the recording material between the transfer portion and the fixing device in a first mode which keep the loop of the recording material within a first range and in a second mode which keep the loop within a second range, a level of the loop within the second range is smaller than a level of the loop within the first range;
- wherein after a leading end of the recording material reaches the fixing device, the controlling device controls the recording material conveyance speed of the fixing device in the first mode, and before a rear end of the recording material reaches the transfer portion, the controlling device controls the recording material conveyance speed of the fixing device in the second mode.
An image forming apparatus comprising:
- a transfer portion which transfers a unfixed image borne by an image bearing member onto a recording material;
- a fixing device which is able to switch a conveyance speed of the recording material and fixes the unfixed image transferred at the transfer portion;
- first and second loop detecting devices which detect respectively different levels of loops formed on the recording material between the transfer portion and the fixing device, the level of the loop detected by the second loop detecting device is smaller than a level of the loop detected by the first loop detecting device;
- and
- a controlling device which controls a recording material conveyance speed of the fixing device in response to a detection result from the loop detecting device, so as to keep the loop of the recording material within a constant range;
- wherein after a leading end of the recording material reaches the fixing device, the controlling device controls the recording material conveyance speed of the fixing device in response to a detection result of the first loop detecting device, and before a rear end of the recording material reaches the transfer portion, the controlling device controls the recording material conveyance speed of the fixing device in response to a detection result of the second loop detecting device.
Dependencies are inferred from the claim text.