It is known to arrange a xerographic printing machine with a retracting stripper baffle to strip the body of the paper sheet from the fuser roll. This baffle, when cold, can cause differential gloss marks on the print between the solid baffle areas and the areas where the stripper fingers need to penetrate through the baffle. This differential gloss is caused mostly by the heat transfer from the hot image disposed on the paper sheet to the colder baffle surface.
Thus, there is a need for an improved fuser stripper baffle.
In a first aspect of the invention, there is described a fuser stripper baffle comprising a multiplicity of protruding fingers, the multiplicity of fingers arranged to strip a paper sheet from a proximate fuser roll, each finger of the multiplicity of fingers forming a protruding distal stripping end and an adjacent upper distal end stripping surface, the distal end stripping surface forming a multiplicity of stepped surfaces, the multiplicity of stepped surfaces extending in an axial direction with respect to an included spanwise direction.
In a second aspect of the invention, there is described a printing machine including a fuser stripper baffle, the fuser stripper baffle comprising a multiplicity of protruding fingers, the multiplicity of fingers arranged to strip a paper sheet from an included proximate fuser roll, each finger of the multiplicity of fingers forming a protruding distal stripping end and an adjacent upper distal end stripping surface, the distal end stripping surface forming a multiplicity of stepped surfaces, the multiplicity of stepped surfaces extending in an axial direction with respect to an included spanwise direction.
Briefly, a fuser stripper baffle exit minimizes differential gloss marks due to paper contacting the fuser exit baffle. Portions of paper that touch the baffle cool differently than portions that don't, resulting in differential gloss in the paper path or spanwise direction. The exit baffle contains a series of axial-direction steps or plateaus in its upper surface, such that the highest step is nearest the fuser roll, while the lowest plateau is furthest from the roll. This reduces the surface area of the fuser stripper baffle exit that contacts the surface of the paper sheet as the paper sheet is stripped from the fuser roll. The paper thus touches the exit baffle for the minimum amount of time, thus minimizing the heat transfer to the baffle. This minimizes differential cooling effects which, in turn, minimizes differential gloss.
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As shown, the baffle finger 10.n is arranged to strip a paper sheet 30 from a proximate fuser roll 50. The finger 10.n forms a protruding distal stripping end 9 and an adjacent upper distal end stripping surface 21. The distal end stripping surface 21 forms a multiplicity of three (3) stepped surfaces or plateaus respectively numbered 13, 15 and 17. With cross-reference to
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In one embodiment, the printing machine 500 comprises a copy machine.
In one embodiment, the printing machine 500 comprises a network printer.
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Thus, in one alternate embodiment, N equals a value less than 7 such as, for example, 6.
Further, in another alternate embodiment, N equals a value greater than 7 such as, for example, 8.
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In summary, in accordance of the present invention, the amount of transfer, and the amount of gloss differential, is substantially reduced by stepping the stripping surface of the stripper baffle to reduce the area in contact with the image on the sheet. This rejection in heat transfer results in a reduced differential gloss on the image. Currently the steps or plateaus are extruded into the aluminum baffle and the openings for the stripper fingers are machined into the extrusion. The geometry of the steps is designed such that the paper as it is stripped from the fuser roll does not have a stub point.
Thus, there is proposed an exit baffle geometry that minimizes differential gloss marks due to paper contacting the fuser exit baffle. Portions of paper that touch the baffle cool differently than portions that don't, resulting in differential gloss in the paper path or spanwise direction. In accordance with the present invention, the exit baffle contains a series of axial-direction steps or plateaus in its upper surface, such that the highest step is nearest the fuser roll, while the lowest plateau is furthest from the roll. This ensures that the paper exiting the fuser rides only on the highest or nearest step, thereby touching the exit baffle for the minimum amount of time, thus minimizing the heat transfer to the baffle. This minimizes differential cooling effects which, in turn, minimizes differential gloss.
Thus there has been described the first aspect of the invention, namely, the fuser stripper baffle 20 comprising a multiplicity of protruding fingers 10.1 through 10.7, the multiplicity of fingers 10.1 through 10.7 arranged to strip a paper sheet 30 from a proximate fuser roll 50, each finger 10.n of the multiplicity of fingers 10.1 through 10.7 forming a protruding distal stripping end 9 and an adjacent upper distal end stripping surface 21, the distal end stripping surface 21 forming a multiplicity of stepped surfaces 13, 15 and 17, the multiplicity of stepped surfaces 13, 15 and 17 extending in an axial direction 32 with respect to an included spanwise direction 31.
In one embodiment, the fuser stripper baffle 20 comprises exactly seven (7) fingers 10.1 through 10.7.
In one embodiment, the fuser stripper baffle 20 comprises exactly three (3) stepped surfaces 13, 15 and 17.
Also, there has been described the second aspect of the invention, namely, the printing machine 500 including the fuser stripper baffle 20, the fuser stripper baffle 20 comprising a multiplicity of protruding fingers 10.1 through 10.7, the multiplicity of fingers 10.1 through 10.7 arranged to strip a paper sheet 30 from an included proximate fuser roll 50, each finger 10.n of the multiplicity of fingers 10.1 through 10.7 forming a protruding distal stripping end 9 and an adjacent upper distal end stripping surface 21, the distal end stripping surface 21 forming a multiplicity of stepped surfaces 13, 15 and 17, the multiplicity of stepped surfaces 13, 15 and 17 extending in an axial direction 32 with respect to an included spanwise direction 31.
In one embodiment, the printing machine 500 comprises a copy machine.
In one embodiment, the printing machine 500 comprises a network printer.
The table below lists the drawing element reference numbers together with their corresponding written description:
While various embodiments of a fuser stripper baffle and a printing machine including the same, in accordance with the present invention, are described above, the scope of the invention is defined by the following claims.
Number | Name | Date | Kind |
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6782228 | Rasch et al. | Aug 2004 | B1 |