Background Of The Invention

The invention disclosed herein relates to a device for preventing the ends of sheet media supported on a sheet media holding and/or stacking apparatus from curling into each other, particularly for a stacking apparatus used with a sheet media handling apparatus which operates on sheet media fed from a roll thereof, such as apparatus for cutting and/or printing, plotting or otherwise recording or reproducing an image or images on the sheet media.

Sheet media draped over a media stacker bar tends to curl, as shown in Fig. 1, particularly when fed and cut from a roll. When the edges of the sheet medium curl into contact with each other or over each other, or otherwise interact with each other, that tends to off balance the curled sheet medium itself as well as any stack of sheet media underlying the curled sheet medium. Off balancing a sheet medium or stack may cause not only the particular off-balanced sheet medium to fall off the stacker bar, but also the entire stack of sheet media stacked on the bar to fall.

The invention disclosed herein provides a simple and inexpensive means to prevent such media curling. Objects And Summary Of The Invention It is an object of the invention disclosed herein to improve holding and/or stacking of sheet media in sheet media handling apparatus.

It is another object of the invention to prevent the edges of sheet media from curling into each other when supported by a stacker bar of a sheet media holding or stacking device. It is another object of the invention to provide a simple and inexpensive device which prevents the edges of sheet media from curling into each other when supported by a stacker bar of a sheet media holding or stacking device.

In accordance with the invention, a separator or deflector is suspended from an elongated supporting element or stacker bar over which the sheet media is draped such that the ends of sheet media supported by the stacker bar are

positioned on opposite sides of the deflector, which prevents the sheet media edges from contacting or overlaying each other.

In the illustrated embodiment, the deflector is a solid sheet of relatively rigid or stiff material which extends below the stacker bar a sufficient distance to prevent the edges of the sheet media supported by the stacker bar from curling below the deflector. In the preferred embodiment, the deflector is a thin sheet of solid aluminum or solid plastic, e.g., Kydex plastic. "Solid" is meant relative to the sheet media, so that the deflector sheet may have holes in it or may be perforated or screen-like or grid-like, and yet prevent the sheet medium from passing through the deflector sheet. The deflector may be connected to the stacker bar in any suitable manner.

The above and other objects, advantages, features and aspects of the invention will be more readily perceived from the following description of the preferred embodiments thereof and the accompanying drawings. Brief Description Of The Drawings

The invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like numerals refer to like or corresponding parts, and in which:

Fig. 1 shows a conventional sheet media stacker bar with a sheet medium suspended therefrom with the edges of the sheet medium curled into each other; Fig. 2 is a rear perspective view, partly broken away, of printing apparatus and media stacking apparatus which incorporates a curl deflector according to the invention; and

Fig. 3 is a side perspective view of an improved stacker bar and the curl deflector according to the invention depicted in Fig. 2 suspended from the stacker bar.

Description Of The Preferred Embodiments

Sheet media holding and stacking apparatus according to the invention is illustrated in the accompanying drawings for holding and stacking sheet media from a printing apparatus which prints on sheet media fed from a roll, cuts the

printed-on sheet medium and deposits the cut sheet medium on a stacker bar. However, the inventive holding and stacking apparatus and the curl deflector may be used with other types of sheet media handling apparatus.

Referring to Fig. 2, sheet media holding and stacking apparatus 10 (referred to simply as "stacking apparatus") is depicted supported by a printer 12 to receive sheet media (one of which 14 is illustrated supported by the stacking apparatus 12) cut by a cutting wheel 16, also supported by printer 12, after the printer has printed a desired image or images on respective sheet media. Stacking apparatus 10 is described in detail in application Serial No. (attorney docket No. HID-226), titled DUAL EDGE CONTACT MEDIA STACKER, filed on the same date as this application. Printer 12 is described in detail in application Serial No. 07/919,666 filed on July 24, 1992 titled "THERMAL STRIP MODE PRINTER COMPONENTS AND SUBASSEMBLIES". The disclosures of those two applications are incorporated herein by reference. Stacking apparatus 10 includes a supporting element or stacker bar 18 over which the sheet media are draped after being cut by cutting wheel 16 mounted on printer 12. Stacking apparatus 10 also includes a curl deflector 50 according to the invention. The stacker bar 18 is horizontally supported movable between a non- loading (first) position not shown in Fig. 2, and a media stacking (second) position at the rear of printer 12, as shown in Fig. 2.

Referring to Fig. 2, the stacker bar 18 is elongated in a first direction (parallel to the Y-axis) and is supported horizontally. The stacker bar 18 includes two edges 21 and 22 extending horizontally parallel to the first direction and spaced apart laterally with respect to the first direction. The edges 21 and 22 are positioned to contact a sheet medium 14 draped over the stacker bar 18. In the embodiment depicted in Figs. 2 and 3, the stacker bar 18 is of trapezoidal shape and includes a horizontal surface 25 (see Fig. 3) and two spaced generally downwardly sloping surfaces 26 and 27 which intersect the surface 25 at opposed ends thereof along lines which define edges 21 and 22 as sharp edges.

Referring to Fig. 2, the stacking apparatus 10 also includes a clamping system which includes three leaf springs 30 located at the media loading position of the stacker bar 18, which position is shown in Fig. 2, and three other leaf springs not shown in Fig. 2 located at the non-loading position of the stacker bar 18. The leaf springs 30 press the sheet medium being loaded onto stacker bar 18 and any sheet media thereunder draped over stacker bar 18 against edge 22 when the stacker bar is in its sheet media loading position shown in Fig. 2, and the other leaf springs press any sheet media draped over stacker bar 18 against edge 21 when the stacker bar is in its non-loading position. Further details of stacking apparatus 10 are described in said application Serial No. (HID-226).

The media curl deflector 50 prevents curling of sheet media draped over stacker bar 18 so that the free edges of the sheet media do not come into contact with each other, or overlap each other, or otherwise interact with each other. As shown in Fig. 3, the edges of sheet medium 14 curl into the deflector 50 which prevents them from curling into each other. As shown in Fig. 3, the deflector 50 is sufficiently stiff so as not to substantially bend under the curling action of sheet medium 14 (and any sheet media in a stack thereof on stacker bar 18). As described in said application Serial No. (HTD-226), the stacker bar 18 is moved between a non-loading position and a media loading position, and deflector 50 is suitably attached to the stacker bar 18 to move therewith. In the embodiment illustrated in Figs. 2 and 3, the stacker bar 18 has a central slot 52 (Fig. 3) therein which receives therein one end of the curl deflector 50. The curl deflector 50 is secured in slot 52 by any means suitable in view of the materials of which the stacker bar and the curl deflector are made, for example, by an adhesive, welding, fasteners, etc. The stacker bar is preferably made of aluminum.

As described above, the curl deflector 50 is a thin sheet of relatively rigid or stiff solid material, i.e., solid relative to the sheet media. The deflector sheet may be completely solid (on a macroscopic level), have holes in it, be perforated, and may be a screen or a grid, etc. The deflector 50 may also be formed by rods or slats which perform substantially the same function as a sheet. The deflector sheet

is relatively rigid or stiff relative to the sheet media so that the sheet media do not appreciably bend the deflector sheet. A completely solid sheet is preferred for aesthetics and because a solid sheet tends to be stiffer than a perforated sheet, screen or grid of the same thickness. The lower edges of the curl deflector 50 are rounded for safety reasons.

The deflector 50 is shown to be a planar sheet of uniform thickness. However, deflector 50 may be formed by a non-planar sheet which may be of non- uniform thickness. Also, while a single deflector 50 is shown, more than one may be provided if, for example, it is desired to space the edges of the media further apart.

While the invention has been described and illustrated in connection with preferred embodiments, many variations and modifications as will be evident to those skilled in this art may be made without departing from the spirit and scope of the invention. The invention as set forth in the appended claims is thus not to be limited to the precise details of construction set forth above as such variations and modifications are intended to be included within the spirit and scope of the invention as defined in the appended claims.