LINERLESS LABEL PRINTER WITH BURST ELEMENT
BACKGROUND AND SUMMARY OF THE INVENTION
In the printing of linerless labels in roll or web form it is of course necessary to separate the individual labels from each other prior to or after discharge of the printed labels from the printer. This is typically done by cutting using an automatic cutter (such as shown per se in U.S. patent 5,638,104), by using a serrated edge and manually tearing the labels along the serrated edge, or by providing perforations or like lines of weakness between labels and tearing at the perf lines, with or without an aid such as a tear off bar or edge. None of these techniques is ideal, especially in high use situations (such as UPS) and when using conventional linerless labels (such as shown in U.S. patents 3,354,588, 5,358,281 , 5,292,713 and 5,324,078, the disclosures of which are hereby incorporated by reference herein) and particularly thermal linerless labels. For example while the utilization of perforations is normally better than the other techniques, tearing of the labels themselves, or bursts that are not clean (e.g. ragged edges), often occur.
According to the invention a linerless label printer, method of handling linerless labels, and a web or roll of linerless labels, are provided which overcome the problems associated with existing techniques. Linerless labels are simply and effectively substantially cleanly separated from each other by using a particularly configured assist element at the printer discharge opening, preferably in conjunction with a particular configuration of the lines of weakness between the labels in a series of labels being handled and imaged by the printer.
According to one aspect of the present invention there is provided: A label printer comprising: A housing having an interior and a discharge opening. A print element within the housing. A mechanism which can hold linerless labels in a web or roll within the housing. And, a blunt protrusion mounted adjacent the discharge opening positioned to allow a linerless label discharged from the discharge opening to be brought into contact therewith prior to separation from other labels. The blunt protrusion preferably simulates a human knuckle. In the preferred embodiment the blunt protrusion or "knuckle" has a substantially semi-circular cross-section at a portion thereof distal from the printer housing. The distal portion of the protrusion may have a
diameter of between about .4-.6 inches (about 1 -1.5 cm), e.g. about .5 inches, and may have either a hemi-cylindrical or hemi-spherical configuration, and where hemi- cylindrical typically a length substantially parallel to or along the discharge opening of about .4-1 inches (1 -2.5 cm). The blunt protrusion is typically either of metal or hard plastic and preferably is of, or coated by, a non-stick material. For example the knuckle may be coated with silicone or polytetrafluoroethylene, or may be plasma coated, such as shown in U.S. patent 5,375,752. With such a coating or construction there is little chance that the pressure sensitive adhesive from the linerless labels will stick to the knuckle. The printer may be of any conventional type, such as a thermal printer, having a thermal print element. Exemplary types of printers are shown perse in U.S. patents 5,560,293 and 4,784,714, the disclosures of which are hereby incorporated by reference herein. The mechanism which can hold the linerless label in a roll configuration in the printer may be a spool, shaft, or other conventional device for this purpose, and may mount the label roll for rotation about an axis substantially parallel to a central axis of the discharge opening.
According to another aspect of the present invention there is provided a web or roll of linerless labels, comprising: A plurality of linerless labels in series, each label having a top imagable surface having adhesive release material thereon, and a bottom having pressure sensitive adhesive. Lines of weakness separating the series of labels into individual labels. And, a substantially central slit provided in each the line of weakness, the slit being at least about one half inch long. The roll preferably further comprises edge slits provided in the line of weakness at side edges of the label. While the lines of weakness may be score lines, fold lines, or crease lines, etc., preferably they are perforation lines having conventional regular length and form perforations. Each of the slits is preferably at least twice as long as each perforation defining the perforation lines, and each slit extends cleanly through the linerless label material and has sharp terminations at the ends thereof.
According to another aspect of the present invention there is provided a method of handling linerless labels in a web or roll with individual in series labels separated by lines of weakness with a substantially central slit in each line of weakness, utilizing a printer having a discharge opening and a blunt protrusion adjacent thereto, comprising: (a) Imaging the linerless labels with the printer, (b) After imaging a label, discharging the label from the printer through the discharge opening. And, (c) pulling the label into
contact with the blunt protrusion at the substantially central slot so as to substantially clearly burst the label from a following label at the line of weakness therebetween.
Preferably the lines of weakness also include slits at the edges of the labels, and also (c) is preferably practiced so that the slits at the edges facilitate substantially clean bursting of the label from a following label. Also, while under some situations a series of imaged labels may be retained in the printer, preferably (b) takes place substantially immediately after the label is imaged in (a). Normally (c) is practiced manually, and (a) thermally, and the method is preferably practiced using the linerless label rolls as described above. It is the primary object of the present invention to provide a simple, functional, and cost effective printer, roll of linerless labels, and method for handling linerless labels, that provide a substantially clean burst of connected labels so that they separate substantially without tearing, fraying, or ragged edges. This and other objects will become clear from a detailed description of the invention and from the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic perspective view of an exemplary linerless label printer according to the present invention with a part of the housing cut away for clarity of illustration; FIGURE 2 is a perspective view of a roll of linerless labels according to the present invention; and
FIGURE 3 is a schematic detail perspective view of a knuckle and labels according to the present invention showing a clean burst of the labels facilitated by the knuckle.
DETAILED DESCRIPTION OF THE DRAWINGS
FIGURE 1 schematically illustrates an exemplary printer 10 according to the present invention. The printer 10 includes a housing 11 with a print element 12, preferably a thermal print element, and a discharge opening 13 in an end wall 14 of the housing 11. The opening 13 has a central axis and the imaged linerless labels, shown schematically at 15 in FIGURE 1 , are discharged therefrom. The print element 12 is in the interior 16 of the housing 11 , as is a mechanism 17 which can hold linerless labels
4 in a web or roll for movement into operative association with the print element 12. The mechanism 17 may be -- as shown in FIGURE 1 -- a spool or shaft for mounting a roll of labels 15 for rotation about an axis 19 substantially parallel to the discharge opening 13. Any suitable conventional structures (such as shown in U.S. patents 5,540,369, 4,784,714, 5,560,293, and 5,417,783) may be provided for feeding the labels 15 from the mechanism 17 to the print head 12, and then to be discharged out opening 13.
The printer 10 described above may be entirely conventional. According to the invention, a blunt protrusion or knuckle 21 is attached to the housing 11 adjacent opening 13 and positioned so that the labels 15 may be easily moved (e.g. manually) into contact therewith. The protrusion 21 is preferably of metal or hard plastic and is composed of or coated by a non-stick material, such as a plasma coating (as in U.S. patent 5,375,752), or coated with silicone or Teflon®.
The protrusion 21 may be attached to the housing 11 in any suitable conventional manner, either substantially permanently (e.g. by welding), or readily removably (e.g. with screws). Attachment to the wall 14 of housing 11 is most convenient. The protrusion 21 may be readily removable so as to allow attachment of different sizes and/or shapes of protrusions 21 , or to allow adjustment of the position of a protrusion 21 with respect to the opening 13.
One desirable exemplary form of a protrusion 21 according to the invention is seen in more detail in FIGURE 3. The protrusion 21 has a proximate portion 23 attached to the wall 14, and a distal portion 24. The distal portion 24 has a substantially semi-circular cross-section, with a diameter 35 of preferably between about .4-.6 inches (about 1-1.5 cm). The distal portion 24 may have a substantially hemispherical shape, or -- as seen in FIGURE 3 - a substantially hemi-cylindrical shape, with a length 26 substantially parallel to the opening 13 and the lines of weakness 27 (hereafter described) in the material of the labels 15. The length 26 is preferably about the length of the line of weakness substantially central slit 28 (hereafter described) or at least about .5 inches, normally about .75 inches or more. The edges 29 may be sharp or rounded. The surfaces 30 at the top and bottom of the protrusion 21 (assuming a substantially horizontal discharge of labels 15 though opening 13) may be flat, or curved, or bulging.
The protrusion 21 is most effective when used with linerless labels 15 having the construction illustrated in the drawings. As seen in FIGURE 2 the labels 15, initially usually in roll form as seen at 32 in FIGURE 2, have a paper substrate 33 with an
adhesive release material (such as silicone) coating 34. Conventional linerless labels are disclosed in U.S. patents 5,292,713, 5,324,078, 5,354,588 and 5,358,281 , the disclosures of which are incorporated by reference herein. Indicia 35 of any suitable type is imaged on the top of a label 15 with the print element 12 (e.g. thermally). The bottom of each label 15 has a pressure sensitive adhesive 36 that will not stick to release material 34. The adhesive 36 may be permanent or removable or repositional. Lines of weakness 27 separate the substrate web which defines the roll 32 into the individual labels 15. The lines of weakness may be score lines, crease lines, or the like, but preferably are regular length and form perforation pert lines, as shown in the drawings. The substantially central slit 28 is a through extending elongated opening in the substrate 34, preferably at least about 1/2 inch long, and at least twice as long as any pert of the perforation line 27. The slit 28 is positioned to be readily movable into engagement with the protrusion 21 , as seen schematically in FIGURE 3.
In the preferred embodiment the roll 32 also has edge slits 38 at the edges 39 of the labels 15. The slits 38 also are each at least about twice as long as the perfs making up the lines of weakness 27, e.g. at least about .4 inches (1 cm) in length and right at (or immediately adjacent) the edges 39.
In the practice of an exemplary method of the invention, using the printer 10 and roll 32 of linerless labels 15, the leading label (15A in the drawings) is imaged by the print element 12 and then discharged through opening 13, to the position seen in
FIGURE 1. The label 15A is then manually grasped by an operator, and pulled up (the preferred direction, but down if the knuckle 21 is below opening 13) so that the slit 28 engages the rounded distal portion 24 of the blunt protrusion 21. This causes a "snap" burst or separation of the label 15A from the next label 15B in series (see FIGURE 3), causing a substantially clean, not ragged or torn, separation between labels 15A and 15B (see FIGURE 3), facilitated by the edge slits 39, if employed. The edge slits 39 are particularly desirable for wide labels 15. The next label 15B is then in position for imaging, and the procedure is repeated.
It will thus be. seen that according to the present invention an effective, simple, and inexpensive printer with novel attachment, method of handling linerless labels, and roll or web of linerless labels, are provided. The while the invention has been disclosed in what is presently the preferred embodiment thereof it is it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent machines, methods and products included within the spirit and scope of the appended claims.