Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
1999-10-19
2001-10-02
Ellis, Christopher P. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S243000
Reexamination Certificate
active
06296245
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a device for picking and feeding a single sheet at a time from a ream accommodated in a tray, preferably though not exclusively suitable for being used in the field of printers, and in particular provided with improvements with respect to devices with similar characteristics developed previously.
In further detail, the device of the invention is of the type comprising a tray containing a ream consisting of a plurality of sheets; a main rotating, feeding roller, and at least one auxiliary roller arranged adjacent to the feeding roller, wherein the tray is normally at a distance from the main feeding roller and is suitable for moving in order to cyclically bring the ream into contact with the latter, so that the sheets of the ream are separated one at a time and fed along a path in a feeding direction conforming to the direction of rotation of the main feeding roller, and wherein furthermore the auxiliary roller is suitable for cooperating with the main feeding roller, by rotating in contact with the sheets thus separated from the ream but in the opposite direction to their feeding direction along the path, to prevent the separating from the ream and the feeding along this path of double sheets by said main feeding roller.
BACKGROUND OF THE INVENTION
A feeding device integrated in an ink jet printer, with the purpose of picking and feeding the sheets from a tray along a printing path towards an ink jet printhead with which the printer is provided, and having substantially the characteristics specified above, is described in an European patent application previously filed by the Applicant and published with No. EP 0 873 876.
In detail, in this previous device, the tray is arranged according to a substantially vertical orientation, so that the sheets of the ream rest and are aligned, through the effect of their weight, against a back wall of the tray. In particular, the sheets are aligned against this back wall along the respective front edges, by means of which the sheets access the printing path. During the approach motion of the tray to the main feeding roller, the front edges of the sheets travel a predetermined path, along which they come into contact with the auxiliary roller, which in turn, being connected in the rotation to the same members that control the movement of the tray, rotates jointly with the approach motion of the latter.
Accordingly this device has the non-negligible drawback that the sheets of the ream can crumple and bend, or even just become deformed, local to their front edge, by coming into contact and sliding against the auxiliary roller, while it rotates, with the risk of accordingly compromising the regular picking of one sheet at a time from the ream and its correct feeding along the printing path by means of the main feeding roller.
In addition, there is the further drawback that the possible crumplings of the front edge produce interference and slide against the printhead, thus dirtying the sheets and/or at any rate causing visible defects thereon, liable to have a negative influence on the quality of printing obtainable using the printer.
Also, the above-mentioned device uses a monodirectional bushing, also called free wheel, for controlling the line feed motion of the sheets during their printing, its function being to connect in rotation a main feeding gear, in turn made revolve by a main motor, with a main feeding roller in contact engagement with the sheets for feeding them along the printing path, only when the main feeding gear rotates in a predetermined direction, leaving it free to rotate with respect to the main feeding roller, when the main feeding gear rotates in the opposite direction.
This solution has the drawback that when the main feeding gear stops at the end of each elementary rotation defining the pitch of the line feed motion of the sheets, the feeding roller tends by inertia to advance at an angle beyond the feeding gear, even though only to a very small extent, determining an error in the line feed motion pitch. As a result, this error, accumulating with other successive ones, may significantly reduce the quality of printing obtainable on the sheets, especially when the dot printing produced with the ink jet head is of the high definition type, and accordingly requires, for best results, the line feed motion of the sheets to be extremely precise, in order to permit the depositing of the droplets ejected by the ink jet head with absolute exactness on the sheets.
SUMMARY OF THE INVENTION
The object of this invention is therefore to produce a device for feeding a single sheet at a time from a ream of sheets contained in a tray, which overcomes the limitations and drawbacks described above and present in previously developed devices, such as in particular the one described in the afore-mentioned patent application filed by the Applicant.
This object is achieved by the device for the feeding of single sheets from a tray having the characteristics defined in the main claim.
REFERENCES:
patent: 4135804 (1979-01-01), Schoppe et al.
patent: 5255903 (1993-10-01), Parsons et al.
patent: 5326091 (1994-07-01), Giacometto et al.
patent: 5358230 (1994-10-01), Ikemori et al.
patent: 5863036 (1999-01-01), Tanaka et al.
De Ambrogio Attilio
Donnis Gian Paolo
Banner & Witcoff , Ltd.
Bower Kenneth W
Ellis Christopher P.
Olivetti Tecnost S.p.A.
LandOfFree
Device for the picking and feeding of sheets from a ream does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for the picking and feeding of sheets from a ream, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for the picking and feeding of sheets from a ream will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2571025