Device for aligning stacked sheets into a book

The invention concerns a device (01) for aligning at least along one edge several stacked sheets (09) into a book, while maintaining the serial order of sheets, said device comprising an editing table (11), having on one of its sides, a front stop (13) for aligning the edges of the sheets (09). The invention is characterized in that upstream of the editing table (11) is provided a support plate (02), whereon the sheet (09) can be set into a bound book with non-aligned edges, and is further provided in the device (01), a sheet feeder (08, 04, 06) whereby the sheets can be conveyed from the support plate (02) towards the front stop (13) of the editing table (11), while forming a stream of subjacent webs.

TECHNICAL FIELD

The invention relates to an apparatus for aligning sheets arranged one above the other in a stack in accordance with the preamble of claim1or2.

BACKGROUND OF THE INVENTION

Such apparatuses are used for example, but in no way exclusively, for aligning printed sheets along at least one edge, with sufficient accuracy, one above the other, with the result that the stack can then be trimmed at the edges. In the case of a fair number of printed products, for example notes of value provided with registration numbers, it is necessary, once the sheets have been printed, to maintain the sequence of the sheets in the stack-forming pile.

EP 06 14 840 A1 discloses an apparatus which is designed in the manner of a vibrating table. A supporting table is provided for this vibrating table, lateral stops being arranged on at least two, adjacent sides of the supporting table and it being possible for these stops to come into abutment against the side edges of the sheets. In order to align the stack of sheets arranged one above the other, the stack is set down on the supporting table and the latter is then inclined in the direction of the two stops to the extent where the side edges of the sheets come into abutment against the stops on account of gravitational force. The vibrating table is then made to vibrate in order thus to loosen the stack of sheets and to allow an aligning movement of the individual sheets relative to one another.

DE 68 09 156 U discloses an apparatus which is intended for aligning items of mail and in the case of which an imbricated stream is aligned to form a stack.

U.S. Pat. No. 4,369,959 A discloses an apparatus for aligning an edge of a plurality of sheets arranged one above the other on a supporting table one side of which a leading-edge stop is arranged. The apparatus contains a sheet feeder, by means of which the sheets are conveyed to the leading-edge stop.

DE 42 36 839 A discloses a carrying plate on which the sheets are set down with non-aligned leading edges and are conveyed from the carrying plate to form an imbricated stream with underlap imbrication.

U.S. Pat. No. 4,570,918 A describes a blowing device which blows air between sheets from the trailing edges thereof.

DE 198 27 531 A1 discloses a feeder with two leading-edge stops and a side lay arranged on its table.

SUMMARY OF THE INVENTION

The object of the invention is to provide apparatuses for aligning sheets arranged one above the other in a stack.

The object is achieved according to the invention by the features of claim1.

The advantages which can be achieved by the invention consist, in particular, in that the stack of sheets with non-aligned leading edges, rather than being set down directly on the supporting table, is set down on an upstream carrying plate. The apparatus here contains a sheet feeder, by means of which the sheets set down on the carrying plate are conveyed separately, and in the form of an imbricated stream, to the leading-edge stop of the supporting table. The sheet feeder here is to be designed such that an imbricated stream with underlap imbrication forms, i.e. the leading edge of each sheet is conveyed in each case beneath the respectively preceding sheet, with the result that, rather than the pile having to be restacked from the carrying plate in the direction of the supporting table, the sequence of the sheets is maintained. Since the sheets in each case are individually conveyed to the leading-edge stop and aligned there, a high level of aligning accuracy is achieved. The design of the apparatus may include the use, in slightly modified form, of known sheet feeders as are used for feeding sheets separately into a sheet-printing machine. In order to modify the design of known sheet feeders, a leading-edge stop has to be provided, in particular, on the supporting table, in the plane of which the imbricated stream is conveyed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The production of the apparatus01illustrated inFIG. 1may be based on a conventional sheet feeder as is used for feeding sheets separately into a sheet-printing machine.

Such sheet feeders have a carrying plate02, on the top side of which the sheets09can be set down in a stack03with sheets09in which at least one side edges has not been yet aligned. By means of the suckers04;06and the pressure-exerting foot08with integrated air nozzle, the sheets09are conveyed separately from the stack03in the direction of the supporting table11. The supporting table11here is designed in the manner of a suction-belt table11with circulating suction belts12.

Use of the suckers04;06, of the stop07, of the pressure-exerting foot08and of the suction belts12results in the sheets09being conveyed from the carrying plate02in the direction of the supporting table11in the form of an imbricated stream with underlap imbrication. Arranged at the rear end of the supporting table11, as seen in the conveying direction of the sheets09, is a leading-edge stop13, against which the leading edges of the sheets09are conveyed by the advancement movement of the suction belts12and are aligned in the process. The alignment of the sheets09on the leading-edge stop13here is assisted by the inclination of the supporting table11in the direction of the leading-edge stop13, since the weight-induced forces acting on the sheets09are divided up into a horizontally acting and a vertically acting component in accordance with the angle of inclination of the supporting table11. In order for it to be possible to vary the weight-induced forces acting on the sheet09, it is thus particularly advantageous if it is possible to change the angle of inclination of the supporting table11.

Continuous feeding of the sheets09from the stack03on the carrying plate02, a stack14of sheets09arranged one above the other forms on the supporting table11, the leading edges of these sheets being aligned on the leading-edge stop13in each case. The sequence of the sheets09here is maintained on account of the underlap imbrication of the imbricated stream.

The sheet09which is to be aligned has to be pushed in beneath the stack14of already aligned sheets09. In this case, the thicker the stack14already is, the higher are the weight-induced forces which act on the sheet09which is to be aligned in each case. In order to prevent those frictional forces between the stack14and the top side of the sheet09to be aligned in each case which counteract the aligning movement of the sheet09which is to be aligned in each case from becoming inadmissibly high, it is possible to provide on the apparatus01a blowing means16, which blows air, in particular ionized air, from the trailing edge of the aligned sheet09, between the respectively foremost sheet09of the imbricated stream and the stack14. As a result, an air cushion is thus formed between the stack14and the next sheet09which is to be aligned in each case, and the friction is reduced correspondingly.

FIG. 2illustrates a second exemplary embodiment of an apparatus21in a perspective view as seen obliquely from above. The apparatus21has a carrying plate22, on the top side of which it is possible to set down a stack23of sheets29with non-aligned leading edges. Arranged above the carrying plate22is a suction means24which can be displaced along three axes and of which the suction cups26can be brought into abutment against the top side of the respectively uppermost sheet29of the stack23. By virtue of a corresponding conveying movement of the suction cups26, the respectively uppermost sheet29of the stack23can be raised up individually and conveyed in the direction of the supporting table27. The suction means24here executes a conveying movement, with the result that the sheets29are consequently conveyed from the stack23in the direction of the supporting table27in an imbricated stream with underlap imbrication.

The supporting table27is designed as a suction-belt table27with suction belts28(seeFIG. 3), with the result that, following separation on the top side of the supporting table27, the sheets29are conveyed in the direction of a leading-edge stop31and are aligned by abutment against the same.

The leading-edge stop13;31can be adjusted to the shape of the leading edge of the sheets09;29, in particular in convex, concave or sloping form.

Continuous conveying of the sheets29with underlap imbrication on the supporting table27results in the formation of a stack32of sheets29with their leading edges aligned in each case on the leading-edge stop31. In order to assist the sheet29which is to be aligned in each case in being conveyed beneath the stack32, a blowing device33is provided, this having a multiplicity of blowing nozzles from which it is possible to blow ionized air into the region between the stack32and the respectively foremost sheet29of the imbricated stream which is to be aligned.

In order for it also to be possible to align the side edges of the sheets29in the apparatus21, there is provided a side-edge stop34, which can be adjusted to the format of the sheets29and against which the side edges of the sheets29can be brought into abutment and thus aligned. In order to assist the aligning movement of the sheets29on the side-edge stop34, a further blowing device36is provided, by means of which it is possible to blow ionized air, from that side of the sheets29which is located opposite the side-edge stop34, between the stack32and the respectively lowermost sheet29which is to be aligned.

FIG. 3illustrates the apparatus21in a further perspective view from beneath, it being possible, once again, to see the various components of the apparatus21.

FIG. 4illustrates the apparatus21with its various components in a view from above.

LIST OF DESIGNATIONS