US3495821A

US3495821A - Transport device and method

Info

Publication number: US3495821A
Application number: US728108A
Authority: US
Inventors: Donald E Raterman
Original assignee: Multigraphics Inc
Current assignee: AB Dick Co
Priority date: 1968-05-10
Filing date: 1968-05-10
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17
Also published as: BE732434A; DE1923869B2; GB1257498A; DE1923869C3; DE1923869A1

Description

United States Patent 3,495,821 TRANSPORT DEVICE AND METHOD Donald E. Raterman, Mount Prospect, Ill., assignor to Addressograph-Multigraph Corporation, Mount Prospect, III., a corporation of Delaware Filed May 10, 1968, Ser. No. 728,108

Int. Cl. B65h 5/06 US. Cl. 271-51 5 Claims ABSTRACT OF THE DISCLOSURE As imaged sheets exit from the fixing section of electrostatic copying equipment, they must be engaged and forwarded into the receiver, and this occurs normally before the image, comprised of a thermoplastic resin, is fully set. In order to prevent tracking of the resin image by the rollers which feed the sheet out, there is provided one or more porous rollers which are impregnated with silicone oil and which are the only members in contact with the imaged surface of the sheet at this point.

BACKGROUND OF THE INVENTION This invention relates to the delivery of copies, especially from electrostatic copying machines, and is addressed to the problem of tracking which sometimes arises when the thermoplastic resinous image is not fully set as the sheet encounters the pull-out rollers which take it from the usual fixing station and place it in the receiver. If the image is still soft or semi-liquid, a portion of the image material may be picked up on the surface of the feed-out rollers and transferred therefrom to background portions of the same sheet or other sheets where no image is desired.

It will be recognized that in certain respects the problem is associated with the speed of machine operation. At low operational speeds the fusing can be accomplished at lower heat levels since the thermoplastic resinous material comprising the image is permitted a longer time in the heating station to come up to its fusing temperature. As the speed of the machine is increased, the temperature of the heating station must be increased in order to compensate for the decreased time the copy sheet spends under the influence of heat. At the greater speeds, and hence increased heat levels, the image tends to remain in a softened condition after it leaves the fusing station at the time the rollers move into contact with the image so that offset will occur. On the other hand, if some means could be devised for preventing the offset in a simple and economical way, the speed and output of the machine need not be limited in this respect and substantial increases could, in many cases, be effected.

Heretofore the image sheet has been fed from the fixing station by means of lightly contacting, relatively impositive feed rollers wherein non-opposed frictional tire portions arranged in staggered relationship deflect the sheet in a slightly wavy configuration, and thereby use the resilience of the sheet to maintain a delicate driving contact with the tires. This arrangement has proved quite satisfactory, but, as the speed of the equipment is increased and also the heat levels, it has been found that even this light contact is sufiicient to cause some track ing because of the softer condition of the image when it reaches the rollers and the higher temperature of the rollers.

It will be recognized, of course, that it is important for accurate paper handling to have the rollers as close to the fixing section as possible so as to maintain control over the sheet. When, as is commonly the case,. the fixing station is of the heat fusing type, this proximity results in an elevated temperature of the rollers which tends to maintain any imaging material which they pick up in a softened condition for ready transfer to surfaces where 1t 18 unwanted.

It would, moreover, be beneficial if the rollers could engage the sheet in a more positive manner to insure a uniform motion through and out of the fixing section of the copier. This is especially the case where heat fusing is used and where, if the sheet overstays its time in the fixer, there is a possibility of charting.

BRIEF DESCRIPTION OF INVENTION According to the present invention, a very simple and exceedingly effective solution to these problems has been discovered. The pull-out rollers are arranged to engage the sheet in a light pressure nip to provide a rather positive feed, and the roller or rollers engaging that surface of the sheet which carries the image are of a porous character and impregnated with silicone oil. It has been found that virtually no image material is picked up by the impregnated rollers, although the image may still be soft and tacky when it encounters them, and consequently the speed of operation of the whole machine can be substantially increased.

DESCRIPTION OF THE DRAWINGS The embodiments of this invention have been illustrated diagrammatically in the accompanying drawings, but it is to be expressly understood that said drawings are for purposes of illustration only and are not to be taken as a definition of the limits of the invention, reference being had to the appended claims for this purpose. In the drawings,

FIGURE 1 is a diagrammatic side elevation of a portion of an electrostatic copier illustrating the invention;

FIGURE 2 is an elevation to a larger scale of the pull-out rollers taken substantially on line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged detail perspective illustrating the improved roller of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawing, the fusing section of the copying machine is indicated at 11, and includes a heating element 13 energized by a source 15 of electrical energy, a reflector 17, and a conveyor 19 upon which the sheets of paper S are carried past the heating apparatus, image face up.

The pull-out roller assembly is designated 21 and comprises a pair of fixed side members 23, 23 which provide rotatable mounting for a lower roller 25, and an upper roller 27, the latter made up of a shaft 29 carrying two sheet contact cylinders 31. The cylinders 31 are arranged for light contact with the surface of roller 25 and form therewith a nip to receive and positively move forward a sheet introduced between them. Suitable means (not shown) of a conventional nature are provided for driving the rollers 23 and 25 at the surface speed of sheets S as they issue from the fuser section 11. The rollers 25 and 27 cooperate to forward the sheets S in turn to the receiver 33.

As previously indicated, the cylinders 31 are of porous material of any of various sorts. Materials which are substantially rigid have been found to be most suitable for the present application. One which has been found particularly useful is powdered bronze, sintered and compressed to form a porous metal body similar to that used in the manufacture of self-lubricating bearings. It will be understood, however, that any porous body of suitable metallic or plastic material can be used for this purpose.

The porous body is then impregnated with a liquid that prevents the adhesion of the softened resin to the surface of the cylinder. The liquid in the cylinder comes to the Feb. 17, 1970 D. E. RATERMAN 3,495,821

TRANSPORT DEVICE AND METHOD Filed May 10, 1968 5l/V7Z'RED POROUS METAL lNP/PEGA/A TED W/T/l S/L lCO/VE OIL "DONALD EZRATERMAN 1N VE'N'TOR 801; L. 60L 05mm AT TOR/81E)