Back to results
US 6,687,469 B2Granted
Image forming apparatus having an end offset avoiding mode based on sheet size
AssigneeCanon Kabushiki Kaisha
InventorRyouta Takane
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeCanon Kabushiki Kaisha
InventorRyouta Takane
Estimating the term…
An image formation controlling device controls, on the basis of the width of a recording sheet on which previous image formation has been effected and a detected temperature at the longitudinal end portions of the heater, the heat fixing operation in the next image forming operation, and having an end offset avoiding mode for inhibiting the image forming operation until the detected temperature drops below a preset reference temperature when the width of a recording sheet used in the next image forming operation is broader than the width of the recording sheet on which the previous image formation has been effected and the detected temperature is higher than the reference temperature. Also provided is a performance priority mode for executing the image forming operation without inhibiting the image forming operation during the end offset avoiding mode thereof and the end offset avoiding mode selectively changeable over.
An image forming apparatus comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
Drawings are temporarily unavailable. Open the PDF at USPTO
With means for controlling the fixing temperature: specially for the axial heat partition
Characterised by the copy material, e.g. postcards, large copies, multi-layered materials, coloured sheet material: characterised by the format or…
Paper: non-standard format
Structural features of the fixing device: heating belt
Term ended 17 Dec 2022 (estimated)
1. Field of the Invention
The invention relates to an image forming apparatus provided with image formation controlling means for controlling a heat fixing operation for an unfixed toner image.
2. Description of Related Art
FIG. 1 is a vertical cross-sectional illustration showing an example of the construction of a laser printer as an example of an image forming apparatus to which the present invention is applied.
FIG. 2 is a flowchart showing an embodiment of the control procedure by the image formation controlling means of the present invention.
FIG. 3 is a flowchart showing another embodiment of the control procedure by the image formation controlling means of the present invention.
Before some embodiments of the present invention will hereinafter be described in detail with reference to the drawings, the structure of an image forming apparatus will be schematically described with a laser printer taken as an example thereof.
In a laser printer 10 shown in FIG. 1, image information sent to the printer 10 from the outside of the printer 10 is imaged as light-modulated information on the photosensitive drum 12a of an unfixed image forming portion 12 by a writing-in optical portion 11, and the light spot thereof is reciprocally scanned in the axial direction of the photosensitive drum 12a, whereby an electrostatic latent image corresponding to the formed image is formed on the photosensitive drum 12a. A toner is supplied from a developing device 12b to the electrostatic latent image on the photosensitive drum 12a, whereby an unfixed toner image is formed thereon. On the other hand, in the lower portion of the image forming apparatus, there are disposed recording sheets P stored in a feed cassette 13 or a feed tray 14, and design is made such that the recording sheets P in the feed cassette 13 or the feed tray 14 are drawn out by a feed roller 13a or 14a, and are fed to the transferring portion of the above-described photosensitive drum 12a in timed relationship by registration rollers 15.
In the transferring portion, the unfixed toner image on the photosensitive drum 12a is transferred onto the recording sheet P, and the recording sheet P now bearing the unfixed toner thereon is transported toward a fixing device 16. The fixing device 16 is provided with a fixing roller 16a as the aforedescribed heater as shown in FIG. 4 or 5, and the unfixed toner on the recording sheet P is heated and fused by the heat fixing operation of the fixing roller 16a and as the result, the toner image is fixed on the recording sheet P. The recording sheet P on which the toner image has been fixed by such a heat fixing operation is delivered onto a delivery tray 17 in the upper portion of the image forming apparatus.