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US 2005/0031386 A1Published application
Image-forming device
AssigneeBrother Kogyo Kabushiki Kaisha
InventorsYasushi Fujiwara, Seiichi Senda, Takehiro Masuda
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Abstract
In a fixing portion, a heating roller and a pressure roller are provided. An angle of separation θ (°), the temperature THR (° C.) of the surface of the heating roller, the diameter DPR (mm) of the pressure roller, and the width WNIP (mm) of a nip part are set to satisfy the following inequality: 114≦0.55 THR−2.36 θ−1.59 DPR+8.62 WNIP≦144.
Claims26
An image-forming device comprising:
- an image-forming portion that forms a visible image on an A4-size recording paper by using developer, the recording paper having four sides, the four sides including a pair of opposite first sides and a pair of opposite second sides that are longer than the first sides;
- and
- a fixing portion,
- the fixing portion including:
- a heating roller having a central axis and a rigid peripheral surface around the central axis, the peripheral surface being heated to a temperature THR (° C.);
- and
- a pressure roller having a central axis and a resilient layer around the central axis, the central axis of the pressure roller being parallel to the central axis of the heating roller, the pressure roller having a diameter DPR (mm), the pressure roller being pressed against the heating roller to allow the resilient layer to be compressed by the rigid surface of the heating roller, thereby causing the resilient layer of the pressure roller to deform and follow the shape of the surface of the heating roller, a nip part being defined as an area of contact between the heating roller and the pressure roller, the heating roller and the pressure roller rotating to convey the recording paper in a recording paper conveying direction through the nip part, the nip part having an upstream end and a downstream end in the recording paper conveying direction, the heating roller and the pressure roller conveying the recording paper through the nip part from the upstream end to the downstream end with a leading edge of the recording paper being one of the first sides, thereby causing the visible image to be fixed on the recording paper, the heating roller and the pressure roller discharging the recording paper fixed with the visible image from the downstream end of the nip part in a discharging direction, the heating roller having a width WNIP (mm) at the nip part between the upstream end and the downstream end, an angle of separation θ (°) being defined within a plane orthogonal to the central axis of the heating roller and being formed between the discharging direction and a tangent to the heating roller at the downstream end of the nip part,
- the temperature THR (° C.), the angle of separation θ (°), the diameter DPR (mm), and the width WNIP (mm) satisfying the following inequality:
- 114≦0.55 THR−2.36 θ−1.59 DPR+8.62 WNIP≦144.
6 more elements
An image-forming device comprising:
- a casing having a top surface;
- an image-forming portion that is provided inside the casing and that forms an image on the recording paper;
- a discharge roller that discharges, in a discharge-roller discharging direction, the recording paper which has been formed with an image by the image-forming portion;
- and
- a stacking portion having a stacking surface that faces upwardly and that receives thereon sheets of recording paper discharged by the discharge roller,
- the stacking surface having a first end that is positioned below the discharge roller and a second end that is downstream of the first end in the discharge-roller discharging direction, the stacking surface being connected to the top surface via the second end, the top surface extending in the discharge-roller discharging direction from the second end of the stacking surface,
- the stacking portion having a crest that protrudes upwardly at a position between the first end and the second end, the crest protruding upwardly, a first part of the stacking surface defined between the first end and the crest being slanted upwardly toward the crest, an angle within a range of greater than or equal to 20 degrees and smaller than or equal to 55 degrees being formed between the first part and a horizontal direction.
4 more elements
Dependencies are inferred from the claim text.