Image forming apparatus having fixing means error detection
AssigneeCanon Kabushiki Kaisha
InventorsYoshihiko Suzuki, Shokyo Koh
Life of this patent
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Abstract
An image forming apparatus includes image forming means for forming an unfixed image on a recording material; a fixing device for heat-fixing the unfixed image on the recording material, the fixing device including a heater for heating the unfixed image, the heater being controlled at a predetermined temperature during a fixing operation, and a temperature detecting element for detecting the temperature of the heater, wherein power supply to the heater is started after production of image formation start signal; and a discriminating device for discriminating an error in the fixing device on the basis of the temperature of the heater a predetermined period after start of power supply to the heater.
Claims48
An image forming apparatus comprising:
- image forming means for forming an unfixed image on a recording material after receiving an image formation start signal;
- fixing means for heat-fixing the unfixed image on the recording material during a fixing operation, said fixing means including a heater for heating the unfixed image, said heater being controlled at a predetermined temperature during the fixing operation, and wherein power supply to said heater is started after production of the image formation start signal;
- a temperature detecting element for detecting the temperature of said heater;
- and
- abnormal condition detecting means for detecting an abnormality in accordance with an output of said temperature detecting element after the image formation start signal and before arrival of the recording material at said fixing means, and for producing an abnormality signal only when the abnormality is detected under circumstances where the output of said temperature detecting element upon start of the electric power supply to said heater indicates a temperature not higher than a predetermined level.
An image forming apparatus, comprising:
- image forming means for forming an unfixed image on a recording material after receiving an image formation start signal;
- fixing means for heat-fixing the unfixed image on the recording material during a fixing operation at a fixing position, said fixing means including a resistance heater, the temperature of which is elevatable from ambient temperature at receipt of the image formation start signal to a fixing temperature before the recording material reaches the fixing position, said resistance heater being controlled at a predetermined temperature during the fixing operation, and wherein power supply to said heater is supplied only after production of the image formation start signal;
- a temperature detecting element for detecting the temperature of said heater;
- and
- discriminating means for discriminating whether said fixing means is in order, in accordance with a comparison between a predetermined level and an output of said temperature detecting element at a time when the recording material reaches a predetermined position, and before the recording material enters said fixing position, wherein a malfunction output signal is generated when said fixing means is not in order.
An image forming apparatus, comprising:
- image forming means for forming an unfixed image on a recording material after receiving an image formation start signal;
- fixing means for heat-fixing the unfixed image on the recording material during a fixing operation, said fixing means including a heater for heating the unfixed image, said heater being controlled at a predetermined temperature during the fixing operation, wherein power supply to said heater is started after production of the image formation start signal;
- a temperature detecting element for detecting the temperature of said heater;
- and
- discriminating means for discriminating an abnormality of said fixing means in accordance with an output of said temperature detecting element, wherein said discriminating means effects its discriminating operation both in a period after input of an image formation start signal and before start of feeding of the recording material and in a period after start of the feeding of the recording material and before arrival of the recording material at said fixing means, and said discriminating means discriminates abnormality of said fixing means before start of feeding of the recording material and discriminates abnormality of power supplied to said fixing means after start of feeding of the recording material.
Dependencies are inferred from the claim text.