JPS6251857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-speed stacking device for paper or foam paper stored in folded form (hereinafter referred to as folded paper). More particularly, the present invention relates to a high speed stacking apparatus that provides positive control over the sheets to fold the folded sheets back into place after they pass through a printing station.

A major problem conventionally encountered in stacking folded sheets at high speeds is the difficulty of refolding the sheets along the creases created during paper manufacture. By moving the folded sheet from its storage tray through the print station and form tractor feed mechanism, the effect of the sheet crease is eliminated and the sheet is not folded along its original fold lines as it is fed toward the sheet receiving tray. This problem is particularly acute when the printing station undergoes incremental feeding in which the paper is stopped for printing and then moved for printing the next line or block. Also, friction and electrostatics during feeding adversely affect paper movement, resulting in sporadic delays and paper jams.

Efforts have been made to provide stacking mechanisms for refolding sheets along their original fold lines or edges. Some devices provide a long free-fall path from the paper release point to the paper receiving tray.
Other devices have used flipper devices that force the free-falling paper back and forth to fold the paper along the fold lines. Additionally, various deflection means have been used to initiate the refolding action of the paper. Regarding these, U.S. Patent No.
Nos. 4,054,283 and 1,856,972 show flipping devices, US Pat. Nos. 3,514,096 and 3,255,662 show deflection devices along stacked walls. With the exception of devices that utilize flippers, each stacker allows the sheets to fall freely as they are restacked in the stacking tray. Although flipper devices provide very precise folding, they are very expensive due to the number of mechanisms required and their inertial speed limitations.

The main object of the present invention is to provide a device for more precisely controlling the movement of successive folded sheets at high speed by restricting the degrees of freedom as they enter the stacking tray. be.

Another object of the present invention is to provide a high speed stacking device for folding sheets along their original folds by using the inertia of the sheets to apply a driving force to refold them along inner and outer folds in a stacking tray. It is to be.

Another object of the invention is to provide free loops in the free-falling portion of the paper to maintain its flexibility during the folding operation so as to allow folding to occur along the original inner and outer fold edges. To provide a stacking device that provides

The above object is to provide a pair of guide surfaces at the paper release point from the paper feed tractor to facilitate folding of the incoming folded paper along the original inner and outer fold lines; This is achieved by keeping the distance between the sheet and the receiving surface of the folding stack smaller than the dimension between the folding lines of the sheet. The alternating inner and outer folds of the paper are folded back and the paper is rolled against the top of this refolded stack to align it precisely with each fold. As such, release of the sheet from its guideway takes place above the receiving surface. The receiver is arranged such that the inner edge of the stack is further away from the release point than the center thereof and the stack receiver tray and the guide for the inner edge are tilted to propel the inner edge along the vertical guide means. A tray is formed.

By making the distance between the release point and the top surface of the paper stack smaller than the distance between the fold lines, the force of the paper delivered against the top surface of the stack is applied to its inner folds without lifting the paper. the paper toward the back plate of the stacker and then push and roll the paper in the opposite direction to properly refold the outer folds. In order to maintain the distance between the top surface of the stack and the release point within desired limits during the stacking operation, a position sensing device for this top surface is provided and controls the height control motor.

Next, embodiments of the present invention will be described with reference to the drawings. The term "infold" or inner crease as used in this description refers to the fold of folded paper that is in contact with the stacked paper alignment surface.
"Outhold" or outer fold refers to the fold opposite the inner fold.

Folded paper 10 in the form of a web is advanced from a supply source (not shown) by a pair of form tractors 13 and 14 and threaded between a reciprocating print head 11 and platen 12 and deflector plate 16 and It is released at the release point 15 between the tractor door 17. Pins 18 around each tractor 13 and 14 engage feeding openings in the edges of the paper 10 to feed the paper 10. A stationary arched support member 19 is additionally provided to support the paper 10 between the tractors 13 and 14 and a ramp 20 directs the paper over the top of the deflection plate. The tractors 13 and 14 are slidable on a square shaft 21 according to the width of the sheet and are fixed by a release clamp 22. Shaft 21 is driven by a suitable motor or drive source (not shown). The number of arch-shaped support members 19 can be increased or decreased depending on the manner in which paper is supported.

Folded sheets 10 are fed toward a stacker, which has stacking alignment panels 30 and stacking trays 31. The alignment panel 30 is supported by a frame 32 and is tilted approximately 15 degrees from the vertical axis. This is frame 3
2 to the deflection plate 16 and serves as a support against which the infolds of the folded sheets 10 come into contact as they are stacked. The alignment panel or plate 30 is provided with ribs 33 that contact the paper. Although the tilt of the alignment panel may range from 5 DEG to 25 DEG, it has been found that a tilt of about 15 DEG is preferred. alignment panel 30
Although the ribs are provided, a plurality of rod members, linear members, or slots may be provided instead of the ribs. It is desirable to minimize friction between the folded portion of the paper and this alignment panel during free fall. The alignment panel 30 is fitted with a screw 34 which is directly connected to a motor 37 and rotatably supported by guide members 35 and 36 on the rear side of the alignment panel 30. This screw is rotated in both directions by a motor 37 mounted on the underside of the frame 32 by an adapter bracket 38.

Attached to the screw by a transfer nut is a stacking tray 31. This tray has a composite surface consisting of a first tray section 40 and a second tray section 41, which forms a perpendicular surface to the alignment panel 30, and a curved transition section 42 joining them. . The first tray portion 40 is lower than the remaining surface portions to accommodate the stacking of the inner folds. The curved transition portion 42 limits the stacking to the inner and outer edges and prevents additional stacking from occurring at the corners of the stack. Stacking occurs when paper folds are not immediately refolded to their previous thickness. While the stacking height is changing, the stacking tray 31 is guided by a bar member 43 attached to the frame 32. The top surface of the stacking tray 31 or the top surface of the stacked sheets and the release point 1
5 is important in producing a reliable stacking operation. The motor 37 is therefore controlled by the height control circuit 45 and the stack height sensing device in order to keep said distance within the required distance with a tolerance of about 1 to 3 cm. The stack height sensing device includes a light source 46 and a light detection device 47 arranged to sense diagonally across the receiving surface. Other sensing devices can be used instead.

In order to prevent the motor from being energized and lowering the tray due to a momentary interruption of the light beam by an incoming sheet that is properly stacking, the height control circuit 45 provides a take advantage of the delay. However, once this delay has passed, the motor is activated to lower the stacking tray.
When the printing device is stopped, the trays are overloaded.
It can be lowered by the ride switch. When the printing operation is restarted after an interruption or stop of the printing operation, the motor 37 raises the tray 31 until interruption of the light beam occurs and then lowers the tray 31 by a fixed step amount. This operation allows for paper removal or for responding to changes in the stack condition during the standstill state.

The paper is moved to release point 1 by tractors 13 and 14.
5, the paper or web is directed downwardly toward tray 31. The height of the tray is adjusted such that the distance from the release point to the paper receiving surface is less than the length of the form but greater than half the length of the form. The paper is first fed long enough by the tractor so that the leading edge of the paper can be manually fed into the tray and folded along the original fold lines in its original folding direction. After this, the stacking device operates independently.

The height of the tray is adjustable by changing the position of the light source 46 and light detection device 47 on either side of the alignment panel 30 to accommodate forms of various lengths. Arrangements must be made so that the distance from the stack to the release point is less than the length of the form so that the descending paper exerts a pressing force, like a drilling action, on the upper surface of the stack. .

As the sheets enter the stacker from the release point, they naturally stack from the outer folds to the inner folds. This is because the outer fold is not subjected to forces during feeding that tend to bend it in the opposite direction. On the other hand, the inner folds are subjected to forces that tend to bend them back while passing through the tractor. This action eliminates the memory effect of folds in the paper that tend to fold back, and the portion of the paper following the inner folds does not tend to fold back toward the outer folds. By bringing the receiving surface of the tray or the top of the stack sufficiently close to the tractors 13 and 14 and the tractor door 17, the paper is forced against the deflection plate 16 and this begins to tend to bend the paper outward. As the tractor continues to push the paper, outward bending of the paper is encouraged toward the outer fold edge. By making the lower edge 4 of the truck door 17 circular, the paper is bent outward and bent. As the tractor continues to push the paper, the paper rolls over the already stacked papers. When the outer fold reaches the top of the stack, the paper begins to curl toward the inner edge.
The folding operation is then repeated for the next outward fold. The deflection plate 16 provides a guiding action to evoke a memory effect that, in combination with maintaining control of the form paper by the tractors 13 and 14 and the tractor door 17, tends to bend the paper along its original fold lines; Additionally, as the paper is pushed towards the stack it begins to undergo a transitional bend which ensures some rolling flexibility. If the stacking tray is not configured to have two heights, the folded edges on both sides will stack higher than the center, resulting in a stacking surface with the inner and outer edges higher than the center. It has a plate shape.

The stacking device described above can be modified in several ways. Such modifications or variations include moving the tray by, for example, fluid means or belt and chain drive means. Also, the means for inputting sheets into the stacking device could be a pressure or friction roller means instead of a tractor wheel. Also, instead of providing ribs on the stacked alignment panels, they may be coated with a low coefficient of friction material.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a folding paper stacking mechanism according to the present invention, and FIG. 2 is a line 2--2 in FIG. 1.
The figure which shows the cross section of the said mechanism along. 10...Folding paper, 11...Printing head, 1
2...Platen, 13, 14...Form tractor, 15...Release point, 31...Stacking tray, 40
...First tray part, 41...Second tray part, 42
... Curved transition portion, 16... Deflection plate, 30... Alignment panel.

Claims (1)

[Scope of Claims] 1. A device for refolding and stacking folded sheets that have been alternately folded along inner folding edges and outer folding edges, wherein the inner folding edges come into contact when the sheets are folded and stacked. an alignment means for aligning the folded edges with each other; a paper receiving tray provided with a paper receiving surface adjacent to and movable along the alignment means; and on the paper receiving surface. drive means for pushing said sheet along an onward path to a sheet release point; and driving means for pushing said sheet at said sheet receiving surface upon contact by a transitional bend as described below with a sheet which has passed said sheet release point. stationary guiding means having a curved surface projecting toward the outer folding edge to guide the paper toward the outer folding edge; When the edge contacts the alignment means, it is directed towards the outer fold edge so as to cause the paper to move through a transitional bend towards the outer fold edge by contacting the paper past the paper release point. a stationary deflection means having a curved surface protruding from the sheet receiving tray; A folding paper stacking device comprising control means for controlling the movement of a receiving tray.