Electronic information, recorded and magnetically stored so as to be processed as software by a central processing unit "CPU" of a computer, must be identified for visual recognition, to allow a human to know the relevance of that information. Such identification by indicia relating to the information, is typically a legend imprinted on a label adhesively secured to a particular portion of the exterior surface of a diskette's substantially rigid rectangular protective cover, referred to as a "casing". The casing is formed by sealing a pair of opposed thin-walled front and rear sidewalls in spaced-apart relationship, along their peripheral edges, the spacing being sufficient to accommodate an electronic data storage disk and a pair of opposed foamed synthetic resinous pads on either side thereof.
The diskette is inserted in a slot in the CPU to be "read". The diskette may also be used in a disk drive means operatively connected with the CPU, or in some other processing unit of a computer. The casing non-removably encases the storage disk, specifically a flexible "floppy" disk of coated synthetic resinous material, which disk is rotatably disposed for rotation about a central transverse or z-axis of the diskette, if the diskette is said to be planarly disposed in the x-y plane, the x-axis being the longitudinal axis, and, the y-axis the vertical.
The lower portion of the casing is referred to as the "label portion" upon which the label is to be adhesively secured; and, the upper portion is referred to as the "slidable gate portion". Each portion is inwardly off-set from the remaining surface portion, referred to as the "uncovered portion" of the exterior surface of the casing. The term "uncovered portion" is used because the "label portion" is to be covered by a label, and the "slidable gate portion" is partially covered by a slidable gate, which is spring-loaded and reciprocably disposed along the upper edge of that portion. The label portion extends over about 60% of the area on one side, referred to herein as the "front label portion" of the diskette, and over about 15% of the area of the other side, referred to as the "rear label portion". The front sidewall of the diskette is said to lie in the vertical x-y plane.
As will presently be apparent, details of the construction of a "standard" 9 cm or three and one-half inches (3.5") substantially square diskette (it is slightly longer or higher along the y-axis than it is wide along the x-axis) are relevant because of the extent to which the construction permits protection of the storage disk from a high temperature heat source, in a heating zone, in which a labeled diskette is to be placed.
This invention is specifically related to a method for removing a conventional label applied to the label portion of the casing with an adhesive, most typically a pressure-sensitive adhesive, and to a device in which the diskette is directly heated, preferably only across its label portion, before the label is manually removed, hence referred to as a "de-labeling means" or "de-labeler".
Much effort has been devoted to the problem of positioning and adhesively securing a single label on a "standard" 9 cm diskette accurately. Though apparatus is now available which can execute such a labeling task satisfactorily, the cost of such labeling of diskettes is prohibitive. Such apparatus is used by producers of software who record and label thousands of sets of diskettes, each set containing from one to a dozen diskettes, or more.
An analogous problem arises with respect to labels secured with a pressure sensitive adhesive ("PSA") similar to those used for labels on diskettes, in those instances where the original labels on casings for 44-Meg and 88-Meg removable cartridges, and casings for other media such as film, cards of various types, cigars, chocolate candies and myriad "notions" sold over the counters of stores. The common feature shared by such casings is that they are geometrical bodies, symmetrical about two axes, and present at least one relatively large surface, front or rear, to which a label is non-removably adhered.
It will be appreciated that with diskettes and removable cartridges, the casing is typically a synthetic resinous material which is itself a poor heat conductor, and facilitates the task of removing the label with a storage medium encased within. In other instances, for example with chocolates, the casing is empty when the label is to be removed.
New, that is "blank" diskettes, whether formatted or not, are sold by most manufacturers without being labeled. Blank diskettes are usually packaged in lots of 10 (ten) or more, in a box of stiff, heavy paper. Also packed in the box, is a folded, large sheet of paper, coated with a release agent, to which blank labels, suitably colored and lined, are releasably adhered. Various other types of imprinted labels are available for use in particular fields of endeavor (say, business accounting) to identify various documents routinely generated in that field. Such labels normally employ some type of indicia conventionally used with a preselected system of identification for various purposes in the field of business accounting.
Identification of the software is typically imprinted on a label by one who plans to use the diskettes (hereafter, the "user") for a particular application. The user of the blank discs labels each disk as it is recorded with information which is to be retrieved, amplifying details of the identification chosen for describing the information on the label, before it is manually positioned and secured within the label portion of the casing.
The user of the diskettes, may be an individual who will use only one or two diskettes at a time; or, a `small user` who will use only a few diskettes, perhaps as many as a couple of dozen at a time; or, a `large user` who may use several thousand at a time. A large user typically identifies diskettes by imprinting appropriate identifying indicia on a paper label, indelibly, with conventional permanent inks. Also identified, are usually the name of the creator of the software, the manufacturer, and distributor or other purveyor of the diskette, each of whom for simplicity, is hereafter referred to as the "seller".
The single label is adhesively secured with its major indicia-bearing portion on the label portion of the front side wall, and, a minor color-coded bottom marginal portion on the rear ("wrap-around label"). Some labels having only a major indicia-bearing portion (and no color-coded bottom marginal portion) are secured only in the label portion and do not extend around the bottom edge of the casing. Besides identification indicia, the label often also carries a warning that the software is protected by copyright, with the expectation that the imprinted label will remain on the diskette for its entire useful life, taking into consideration how difficult it is to remove a label from a diskette.
It is in the best interest of the seller of the software that the label, once adhered to the diskette's synthetic resinous casing, be non-removably adhered to the exterior surface thereof, so that the diskette may be manually handled a very large number of times without a significant risk that the label will be delaminated while the diskette is in use in the CPU; and also that the diskette may be stored essentially indefinitely without fear of having the label come off due to aging or oxidation of the adhesive bonding the label to the exterior surface of the casing. For durability, the casing is typically made from high impact styrene (HIPS), high density polyethylene (HDPE), or propylene (PP), appropriately filled with fillers, stabilized against degradation by heat and light with stabilizers, and colored with dyes or pigments.
Further, a seller who wishes to be remembered by the user, has no reason to want to remove a readily visible, identifying label from its substrate diskette.
These very reasons result in users, and particularly large producers of software, providing labels which are adhesively secured so tenaciously with a water-insoluble adhesive composition, that the high difficulty of removing the labels effectively thwarts any serious attempt to do so.
Particularly with casings of HDPE and PP, the logical way to remove a label would be to use a solvent since HDPE and PP are substantially insoluble even in commonly available aggressive solvents. Solvents such as acetone or methylisobutyl ketone (and `finger nail polish remover`), xylene(s), toluene, tetrahydrofuran (THF), and many others, would appear to be able to penetrate through the paper and quickly dissolve the adhesive sufficiently to loosen it. However, even if the sidewalls were sealed (in most diskettes they are not) in fluid-tight relationship at their respective perimeters, and also sealed around the edges of a corner window in which a slide is movable to ensure that data on the storage disk will not be erased, there is an open circular central aperture about 2.7 cm (1.0625") in diameter, in one (rear or reverse) sidewall, through which solvent would enter the casing if the label was dipped in a bath of solvent. The lower portion of the periphery of the aperture is well below the upper edge of the indicia-bearing portion of the label (viewed with the slidable window as being the upper edge of the diskette). Solvent leaking into the casing around the periphery of the aperture will destroy the storage disk. The aperture is open for a metal driven disk about 2.5 cm in diameter (0.984") and about 2 mm (0.075") thick, upon which driven disk the storage disk is mounted for rotation about a central transverse axis (z-axis).
Clearly, the use of solvents known to dissolve the adhesive, do not lend themselves for use in this application because the diskette cannot be dipped into the solvent.
To avoid dipping a diskette, it has been bathed with a solvent, but this requires swabbing the label with solvent for too long a time. Most adhesives in current use are neither easily nor speedily dissolved at room temperature (20.degree. C.) by such solvents. If the casing is solvent-sensitive, a portion of the casing is also dissolved.
Bathing or swabbing a diskette is successful only if used to remove residual adhesive, to `finish clean` a diskette. Thus swabbing has been used to finish clean a diskette after the label has been laboriously scraped away with a sharp edge. (see article in IBM Users Forum; GO IBMNEW).
In any case, an attempt to bathe a label on the diskette sufficiently long with a suitable organic solvent, adequately to dissolve the adhesive, is both, too time-consuming and too frustrating to be justifiable. In practice, the relatively low cost of a diskette results in the old, labeled diskette being discarded as waste.
Since so much effort is devoted to labeling a diskette, whether it has been manually labeled, or labeled with a sophisticated apparatus for doing so, it appears incongruous then, to seek to remove the label. But removing an existing imprinted label is highly desirable if a diskette is to be recycled.
Not surprisingly, a seller will consider recycling its diskettes, only if there was a practical method for recovering an essentially "clean" diskette. Recycling once-used diskettes becomes particularly attractive in some not-so-unusual circumstances. For example, when a software program is found to have a "bug", or, the old program has been updated with a new program, and the former made obsolete, there may be several thousand diskettes, or sets thereof, which would be scrapped if they could not be economically recycled.
It will be evident that there can be a strong economic incentive for a seller to reuse the labeled diskettes of the no-longer-saleable diskettes, by the simple expedient of superposing a new identification label over the old. However, even if great care is exercised to position another label precisely over the first, it is difficult to hide the fact that a first label lies beneath the second.
In addition to corporate sellers of software, whether large entities or small, there are many individuals and organizations who use hundreds of diskettes for some specific project or projects, and each diskette is carefully labeled for obvious reasons. When one of the projects, or all the projects come to an end, and there is no reason to save the labeled diskettes, it is highly desirable that they be reused, not only from the standpoint of saving the cost of purchasing virgin diskettes, but also from that of conservation, to avoid dumping them to a landfill, incinerating, or otherwise disposing of the "used" diskettes.
Another occasion to recycle diskettes presents itself when a small user finds he has collected a multiplicity of diskettes on which data are recorded, but which he does not need to store. Much as the user would like to re-use those diskettes, the impracticality of delaminating the old labels from the casing of the diskette, and the unsightly result of superimposing a new label over the old, results in the labeled diskettes being discarded.
Most purchasers of software do not want to purchase software which is sold in an overtly "used" diskette even if they are well aware that a properly "recycled" diskette is of no less quality than a fresh, new or `virgin` diskette.
Because, to date, the labels cannot be removed by any practical method without damaging the recording medium within the casing of the diskette, or the casing itself, those who wished to reuse or `recycle` a labeled diskette for any one of the foregoing reasons, inter alia, either placed a second label over the first, or painstakingly scraped the printed label off the casing of the diskette. Even scraping a label off is not satisfactory because much, if not most of the adhesive remains on the casing, causing a fresh label to be warily or non-planarly readhered on the casing.
On the assumption that one is not averse to recycling a diskette and re-identifying it by a second label superimposed on the first, it will be evident that re-using the diskette for successive documents, each of which are correspondingly identified with new labels, successively superimposed one upon the last preceding one, will soon result in a thickness which will not permit the diskette to be slidably inserted in its slot in the CPU. Even if the slot was able to accommodate a diskette with multiple labels laminated one upon another and to the casing of the diskette, most users of diskettes have a marked aversion to re-using diskettes with multiple overlaid labels, if for no other reason, because of the peculiar aesthetics which are inculcated in PC (Personal Computer) users.
Finally, in view of the fact that the manufacturers of 5.25" floppies, 3.5" diskettes and other magnetic devices for storing data, usually caution against storing such devices in a hot room, users are careful to avoid exposing diskettes to heat. It is well known that diskettes are heat-sensitive. Yet, it is heat, precisely applied for a short time, which provides the solution to the problem. Moreover, a preferred device in which the diskette(s) can be heated, is simple in construction, the basic structural and control elements of the device being well known in the art of toasters for toasting slices of bread and the like. The simple construction of such a device, whether for cleaning only one diskette at a time, or plural diskettes at a time, in a batch operation, or cleaning a multiplicity of diskettes continuously, makes the de-labeler of this invention the key to recycling already-labeled diskettes.
A continuous diskette heater is constructed with the same principles in mind as in a continuous toaster for slices of bread which must be toasted to the "just right" color without being overly darkened or charred.
This invention is directed to a practical solution to the problem of removing a label, which is non-removably adhesively secured to a "standard" diskette with a thin layer of heat-sensitive adhesive, without damaging either the casing of the diskette or the storage disk on which data is to be magnetically stored, and more specifically to the problem of cleanly parting the label from the surface of a diskette without leaving a substantial amount of adhesive on the surface of the diskette. The best solution to the problem is to remove the label when the adhesive bond has been vitiated sufficiently to cause viscous deformation of the adhesive layer, to cause adhesive failure where the adhesive exhibits a higher degree of elastic response or rubbery behavior, so that the label can be parted cleanly from the surface of the label portion of the casing.