GB2223040A - Apparatus for decurling paper - Google Patents

Description

2 223 0 4 0 1 APPARATUS FOR DECURLING PAPER This invention is concerned

with apparatus for decurling paper.

In our copending application Nos. 8826698 (Serial (8915591) No.) and (Agents ref. 8204)(Serial No.

there are disclosed paper decurling devices which feed paper through an arched gap, without applied pressure to press the paper, to remove curl from paper as it exits from copying machines, printers and the like, primarily of the type wherein paper may contain moisture which dries unevenly in the presence of heat at an image fusing station of an electrostatic copier or printer. Such decurlers and offsetters are disclosed in our prior applications may also have application to facsimile machines.

However, most commercially available facsimile machines employ a thermal transfer or printing process using treated paper which is smooth, slick, thin and inherently curled by storage in a roll, instead of in sheets. The curl imparted to the paper by virtue of being stored in a roll is mechanical in nature, as distinguished from curl induced by uneven removal of moisture. Therefore, while our prior decurlers and offsetters may be somewhat useful in removing curl mechanically set in paper, the optimum result from the prior devices are recognised when removing curl induced by removal of moisture at a print station.

The present invention contemplates removal of curl from paper exiting an image reproducing machine, such as a copier, printer or facsimile machine which is most advantageously employed in conjunction with such a machine in which paper curl is mechanically induced, as particularly is the case when the paper is stored in a roll.

es a structure Further, the invention contemplat in which, during the decurling of the Daper, it can be shifted laterally so as to cause the ultimate sheet of paper leaving the apparatus to be laterally offset to allow job separation or offsetting.

More particularly, the invention contemplates decurler through which paper is transported from reproducing machine to a receiver, wherein the paper is subject to corrugating pressures or forces such that the tendency of the paper to re-curl upon leaving the apparatus is reduced.

Still more particularly, the invention contemplates such a decurler in which the means for applying corrugating pressure is adapted to be laterally shifted to offset the location at which the de-curled paper is deposited, thereby facilitating job offsetting.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Fig. 1 is a side elevation showing the apparatus of the invention in conjunction with a printing machine; Fig. 2 is a horizontal section on the line 2-2 of Fig. 1; Fig. 3 is a vertical section on the line 3-3 of Fig. 2; Fig. 4 is a fragmentary view on the line 4-4 of Fig. 3; and Fig. 5 is a fragmentary view on the line 5-5 of Fig. 2.

As seen in the drawings, referring first to Fig. 1, a sheet decurler and offsetter D is shown in conjunction with a printing machine F of the type in which a paper supply is provided on a roll R. A typical printing machine is a facsimile machine adapted by telephone communication to print a message or other matter on a strip of paper. In most cases present day facsimile machines employ thin paper which is treated and adapted to receive the image in a thermal transfer process at a print station (PS) as the paper is moved through the printer and engaged by exit rolls 10 for discharge into a receiving tray 11. In the process the strip of paper is cut 1 1 to sheet size at a cutting station (CS) before moving from the exit rolls to the receiver. When the strip is cut the sheet tends to curl because of the inherent set induced in the paper sheet by reason of the fact that is has been stored in a roll. As a result of such curl, sheets entering the receiver do not stack neatly and later handling a copy is a problem.

Also, in the customary use of facsimile machines, jobs or work received are stacked one on the other, as received, including jobs of one or a plurality of sheets. In such cases, the manual separation of jobs is difficult because the paper is curled, thin and slick.

In accordance with the preferred embodiment of the invention both the curl problem and the job separation problem are resolved, but it will be understood that the decurling function and structure need not necessarily be performed with or adapted to perform the job separation or offsetting described herein.

In any case, a sheet of paper is fed by exit rolls 10 to the throat or inlet 12 of the decurler D, and then the sheet is transported by decurler or corrugating means 13 to the receiver 11. The 1 1 k, r details of construction of the decurler or corrugating means 13 and their mode of operation will best be understood by reference to Figs. 2 to 5.

As seen in Figs. 2 and 3 to best advantage, the decurler and corrugating means 13 include an elongated assembly comprising an upper paper guide 14 and a lower decurler form 15 having outwardly divergent flanges forming a sheet entry throat 12. The guide 14 and form 15 are assembled between and suitably integrated with end pieces 16 at opposite ends of the decurler.

Extending horizontally between and through end pieces 16 is a paper feed shaft 17, adapted to be rotatively driven by drive means 18, at one end, and to be longitudinally shifted by an offsetting drive 19, at the other end. Paper feed tires or resilient rings 20 are fixed on the shaft 17 in longitudinally spaced relation. These feed tires extend into an arcuate cavity 21 in the decurler form, and, in accordance with our pending applications referred to above, the arcuate cavity and the drive tires are formed on radii to provide a gap 22 of a dimension in excess of the paper to be decurled. With such a structure a decurling function takes place in the gap as a bending force is applied to 1 the sheet and the sheet is moved through the gap due to friction caused by deflection of the sheet into the arcuate cavity 21 by the tires 20.

However, in the case of paper which has been stored in a roll, as indicated above, the paper tends to take a set, so that the bending of the sheet in the decurlinggap may not be fully effective to remove the curl, which is more pronounced or tighter as the diameter of the roll decreases during paper consumption. Decurling of the paper is better assured in the case of the present invention by utilization of corrugating means which include, in conjunction with the feed tires 20, a plurality of ribs 23 spaced lengthwise of the feed rolls 20 and extending arcuately from the region of the paper inlet or throat 12 between the feed tires. In some forms, the corrugating ribs 23 may be formed on or attached to the decurler form 15, in the case that the invention is to be employed without benefit of offsetting jobs.

As shown, however, the decurler is also adapted to offset jobs by longitudinally shifting shaft 17 and ribs 23, together between positions at which sheets are deposited on the receiver in offset,.but overlapped relation to facilitate job separation.

As best seen in Figs 2 and 3, the corrugating 4 k ribs 23 are formed as part of a bar 24 having a dovetailed sliding fit in a groove 25 in the decurler form 15. The ribs 23 are formed as part of the bar and extend arcuately - into the gaps 22, terminating at approximately the vertical center of the feed tires 20. Shaft 17 and bar 24 are interconnected to cause corresponding longitudinal motion by means, as illustrated, of a collar 26 fixed on shaft 17 and rotatably extending into a slot 27 in bar 24.

The drive means 18 for rotating shaft 17 are seen best in Figs. 2 and 4, wherein it will be seen that a drive motor 118 is supported on end member 16 and has a drive shaft connected to a gear 119 for driving a gear 120 connected to shaft 17 by a splined connection 121. Shaft 17 is supported in bearings 116 in end plates 16 for longitudinal sliding and rotary motion. The splined connection causes the rotary motion while permitting longitudinal motion. The longitudinal motion is imparted to the shaft 17 by the offsetting drive means 19 seen in Figs. 1 and 2. A motor 219 is mounted on the end plate 16 and has a pinion 319 engaged with a rotary rack 419 on shaft 17, whereby reversal of motor 219 will shift shaft 17 in opposite directions. As noted above, the corrugating ribs 23 are also shifted with the shaft 17, due to the connection provided by collar 27.

1 Motors 118 and 219 are controlled in a suitable manner. Motor 118 will be energised to feed and decurl sheets at any time that the host machine is operating to produce sheets. On the other hand, when offsetting of jobs is desired, the offsetting motor is controllable by suitable power and directional controls to shift the feed shaft 17 and corrugator member 24 in opposite directions to cause the sheets to be deposited in the receiver in offset relation. In the case that the host machine is oDerable unattended, the host machine would preferably be equipped to sense the start and finish of jobs or the receipt of facsimile transmissions to automatically cause the jobs to be offset.

Referring to Fig. 5, the corrugating method performed by the invention will be seen with greater clarity and in exaggerated proportion. The paper, as it passes through the arcuate cavity 22 between the feed tires 20 and the decurler form 15 is subjected to corrugating forces by being depressed into the spaces between the corrugating ribs 23, because the feed tires are of sufficient diameter to project downwardly past the upper surfaces of ribs 23, but without pressing the paper against the decurler form 15. In addition, the tires 20 and ribs 23 are laterally spaced so as to not press the paper between opposing 1 side faces. Also, to minimize tendency of the deforming pressure on the paper to cause marks or creases in the paper, all side edges of the tires and ridges may be broken or curved.

Because the sheet is forced into the undulated or corrugated shape, sufficient to overcome the curl, the paper does not readily re-assume the curl because of the slightly corrugated set or stress in the paper which resists the curl.

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Claims (5)

CLAIMS:

1. Apparatus for decurling paper exiting from a printing machine with a tendency of the paper to curl, comprising: feed means for moving the paper to a receiver, and means cooperating with said feed means to apply a corrugating pressure to said paper.

2. Apparatus as claimed in claim 1, wherein said feed means includes a plurality of spaced tires to engage the paper transversely of the direction of paper movement, and the means cooperating with said feed means includes a plurality of ribs disposed between said feed tires to deform the paper into the space between said feed tires.

3. Apparatus as claimed in claim 1, said feed means and said means cooperating with said feed means being shiftable transversely of the direction of movement of the paper to offset paper in said receiver, and including means for shifting the same.

4. Apparatus as claimed in claim 1, wherein said feed means includes a plurality of spaced tires to engage the paper transversely of the direction on paper movement, and the means cooperating with said feed means includes a plurality of ribs disposed between said feed tires to deform the paper into the space between said feed tires, said feed tires V_ 1 11 and said ribs being shiftable transversely of the direction of movement of said paper to offset paper in said receiver, and including means for shifting said feed tires and said ribs.

5. Apparatus for printing on paper stored on a roll and supply cut printed sheets to a receiver, including means for feeding the cut sheets to said receiver, and means for applying a corrugating pressure to the sheets during feeding of said sheets to said receiver.

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