CA1099236A - Device and method for release of labels from label transfer wheels - Google Patents
Device and method for release of labels from label transfer wheelsInfo
- Publication number
- CA1099236A CA1099236A CA303,232A CA303232A CA1099236A CA 1099236 A CA1099236 A CA 1099236A CA 303232 A CA303232 A CA 303232A CA 1099236 A CA1099236 A CA 1099236A
- Authority
- CA
- Canada
- Prior art keywords
- label
- heat transfer
- transfer wheel
- wheel
- release
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65C—LABELLING OR TAGGING MACHINES, APPARATUS, OR PROCESSES
- B65C9/00—Details of labelling machines or apparatus
- B65C9/20—Gluing the labels or articles
- B65C9/24—Gluing the labels or articles by heat
- B65C9/25—Gluing the labels or articles by heat by thermo-activating the glue
Landscapes
- Labeling Devices (AREA)
Abstract
DEVICE AND METHOD FOR RELEASE OF
LABELS FROM LABEL TRANSFER WHEELS
ABSTRACT OF THE DISCLOSURE
Release agents and applicator devices therefor are described for heat transfer wheels which deposit address-bearing labels onto articles being labeled. The release agent applied to the heated surface of the wheel prevents the offset of the printed matter on the wheel surface.
Exemplary of the release agents are the mercapto-functional polysiloxanes.
LABELS FROM LABEL TRANSFER WHEELS
ABSTRACT OF THE DISCLOSURE
Release agents and applicator devices therefor are described for heat transfer wheels which deposit address-bearing labels onto articles being labeled. The release agent applied to the heated surface of the wheel prevents the offset of the printed matter on the wheel surface.
Exemplary of the release agents are the mercapto-functional polysiloxanes.
Description
g~ ;231~i sACKGROUND OF THE INVENTION
This invention relates to article labeling machines, and more particularly, to reIease agents and applicator devices ~or applying release agents upon heat transfer wheels for use with article labeling machines.
Certain automatlc addressing and labeling machines for addressing or labeling arkicles, for example envelopes, utilize a rotatable, heated transer wheel to carry the address-bearing iteml normally referred to as a label, into physical contact with the article being addressed. The addressing or labeling machine incorporates suitable article transport means to bring the articles, one at a time, into operative position with the label transfer wheel.
In some applications, the labels themselves are physically attached to the articles and in this type of application, the labels carry a heat activated adhesive on their underside to enable the labels to be secured to the articles. During the relatively short interval while the label is borne by the label transfer wheel from the label supply point to the point where the label is transferred to the article, the trans~er wheel must heat the label sufficiently to activate the adhesive.
In effecting the aforedescribed transfer and adhesion of the label to articl~s, the heat input to the label supporting pad or surfac~ o~ the tran~fer wheel, which in turn is transmitted ; to the label itseI~, is critical. If too little heat is pro~ided, the label may not adhere to the article. On the other hand, too much heat ~ay result in the label sticking to the heat wheeI, incomplete adhesion o~ the label to the substrate or damage to the labeI.
The address or other label information carried upon the label is frequently printed upon the label with toners or inks which tackify or otherwise activate the ink or toner.
For example, when xerographic printing techniques are used to print label information, the toners used to make the label information visible by well-known xerographic imaging techniques; often tackify when subjected to the heat which activates the adhesive. This causes the label information to offset upon the surface of the heated transfer wheel and thereby causes a ghost image of the label information to appear on at least the next succeeding label. This offset phenomenon is a well-known term and problem charac-teristic of the xerographic art and is defined in the same erms herein. This problem is even more acute because the bare metal heated surface of the heat transfer wheel conkacts the label information side of the label.
_UMM~RY OF ~HE INVENTIOI`I
It is an object of an aspect of this invention to provide an improved article addressing machine.
; 20 It is an object of an aspect of this invention to provide an improved heat transfer wheel for article addressing machines.
It is an object of an aspect of this invention to provide a device and method for preventing the offset of - 25 label information upon the heated surface of heat transfer wheels in article addressing machines.
An object of an aspect of this invention is to ;~ provide a device and me~hod for preventing the offset of label information and improviny the release of address labels having label information printed thereon from the heated bare metal surface of the heat transfer wheel in an article addressing machine.
These and other objects are accomplis~led by applying a film of release agent comprising a polymer having functional groups on the surface of the heat transfer wheel so that there is a film of the release agent on the surface of that portion of the heat transfer wheel which contacts the label, when the label contacts the heat transfer wheel.
~n ~pec~ ~
In accordance with~the piesent invention, there is provided a method of applying labels having heat activated adhesive on one side and printed label information on the other side to a substrate by means of a heat transfer wheel in an article addressing machine comprising forming a film of a release agent for the printed label information on the surface of the heat transfer wheel. In those embodiments where a heated pad is provided on the heat transfer wheel, then the release agent is applied to the surface of the heated pad which contacts the side of the label having printed label information thereon, and as used herein, the -terminology heat transfer wheel encompasses a rotatably mounted base member having at least one heated label transfer pad thereon.
The release agent applied to the heat transfer wheel comprises a polymer having functional groups thereon.
The functional groups include carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof.
The polymer having functional groups is fluid (liquid) at the temperature of the heat transfer wheel.
After the filrn is formed on the surface of the heat transfer wheel, the side of the label having printed label - information thereon contacts the heat transfer wheel to soften or activate the adhesi~e on the other side of the label. Thus, the heat of the heat transfer wheel must be . ' ' ~ "' ~ , suf~icient to so~ten, tacki~y or ac~i~ate ~he a~hesive sufficiently to cause the adhesive to stick to the substrate to which it is appliea. ~any of the inks, toners and/or developers used to print the label information also soften or tackify when heated by the heat transfer wheel. This causes a part of the printed label information to stick to the heat trans~er wheel. A portion of this information remains on the surface of the heat transfer wheel when the label is separated therefrom and applied to the substrateO
This information remaining on the heat transfer wheel prints out on the next subsequent label forming a "ghost" or residual or "offset" image. By applying the film of release agent comprising a polymer having functional groups thereon in , accordance with the present invention, this problem of ; 15 offsetting or printing of a "ghost" or residual image on the next successive label is eliminated.
After the adhesive on the back side of the label, that is, on the side of the label opposite the printed label information, is sufficiently softened by the heat ` 20 supplied h~ the heat transfer wheel so that the adhesive is "active" or sticky enough to adhere to the substrate to which it is to be applied, the adhesive side of the label is ` brought into contact with the substrate and thereafter allowed to cool on the substrate. The heat transfer wheel presses the label having the heated adhesive thereon against the substrate, and the label is released from the heat transfer wheel having the release agent thereon. The label then cools to ambient and the softened adhesive and printed label information hardens, that is, they return to their non-softened state.
9;~:3~
In accordance with another aspect of this invention there is providecl in an article labeling device of the type having a heat transfer wheel for transferring a printed label onto an article, at least a part of said wheel having heating means for contacting and heating the label to activate adhesive on the labeI to enable the label to be secured to the article, the improvement comprising means for metering a release fluid on at least that portion of the wheel which contacts and heats the label. One side of the label contains a heat~softenable adhesive and the other side of the label contains the printed information, both of which are applied to the label prior to contact with the heat transfer wheel. The release fluid metered on the heat transfer wheel must be a fluid which prevents or substan-tially eliminates the "offset" problem discussed above.
Other objects and-features of the invention will be apparent from the following description and drawings.
Figure l is a side elevational view of an address-ing machine incorporating a typical release fluid met0ring device for metering release fluid on the heat transfer wheel in accordance with the present invention, the metering device being out-of-contact with the heat transfer wheel in the illustrated position.
Figure 2 is a side eIevational view of an address-ing machine incorporating a typical release fluid metering device for metering release fluid on the heat transfer wheel wherein the metering device contacts a label transfer g~36 device on the heat transfer wheel in the position illustrated.
Figure 3 is an enlarged side elevational view of a typical release fluid metering device in contact with a heat transfer wheel.
Figure 4 is a side elevational view of another typical release fluid metering device in contact with a heat transfer wheel.
DESCRIPTION OF THE 3?R3~FERRED: EMBOD~IMENTS
Referring to Figures 1 and 2 of the drawings, there is shown an exemplary automatic addressing machine 5 incorpo-rating label transfer wheel 10 and the release fluid metering device 80 of the present invention. Addressing machine 5 ~` includes a housing or cover 9, parts of which have beenbroken away in Figures 1 and 2 to show the construction of certain operating components therewithin. Addressing machine 5 has an article supply magazine 12 within which articles to be labeled are stacked, the walls 13 thereof being adjustable to accommodate articles of varying sizes. Article conveyor , 14 is employed to move articles discharged in seriatim from magazine 12, under gate 15 and pinch roller 16, past label transfer wheel 10 where the labels are transferred to the articles. The article conveyor 14 comprises one or more ; endless belts 17, supported by drive and idler rollers 18 and 19 respec-tively. Roller 18 is driven by suitable motor means (not shownl in the direction shown by the solid line arrow in Figures 1 and 2.
Labels are supplied to head 22 of addressing machine 5 from a suitable source, normally in the ~orm of an uncut sheet (not shown) having multiple label rows. Labeling head 22 includes suitable means (not shown) to advance the label Z3i i sheet forward as required to a guillotine type knife 23 which serves to cut the label supply sheet transversely into strips of several labels each. The strips rest in a downwardly inclined chute-like member 24 and are advanced therealong in the direction of transfer wheel 10 by intermittently driven pinch roll pair 25 to knife and anvil pair 26.
Knife and anvil pair 26 cooperate to cut the strip into individual labels which are discharged therefrom onto surface 86 o~ pad or land 30 of transfer wheel 10 as land 30 comes opposite the knife and anvil pair 26 during rotation of wheel 10. From there, wheel 10, which rotates in the directio~ shown by the solid line arrow of Figures 1 and 2, carries the label into physical contact with the articles being labeled as the articles move therebelow on conveyor 14.
It is understood that the several label supply components of labeling head 22 aforedescribed are operated in timed relationship with one another and with transfer wheel 10 and article transport 14 to assure the requisite supply of labels to transfer wheel 10 as required.
To assure the requisite pressure contact between the labels on surface 86 or pad or land 30 of transfer wheel 10 with the articles on transport 14, there is provided opposite transfer wheel 10, a support roller 28 for transport belt 17. Roller 28 is rotated in the direction shown by the solid line arrow in Figures 1 and 2 from the addressing machine motor (not shown). Although it is not always necessary, vacuum is used in the embodiments of Figures 1 and 2 to provide vacuum to land 30 for progressively drawing the ]abels into vacuum at~achment with surface 86 of pad or land 30.
Numeral 75 represents several vacuum lines used in the preferred embodiment illustrated~ The surface of the land, pad or heat transfer wheel which contacts and heats the adhesive on the label may be fabricated from any suitable material including aluminum, anodized aluminum, steel, nickel, copper, beryllium, silver, gold and the like and alloys of the foregoing.
Various labeling devices and their operation including the printing of the labels are well known in the art. Representative of these devices and for the purpose of illustration onl~ are the disclosures of Rod in U.S~
Patent No. 3,894,909 and of Hubbard in U.S. Patent No. 3,660,208, both references being incorporated herein by reference. These references illustrate the elements of labeling devices.
In Rod there is disclosed a label addressing device, and the claims cover an improved label transfer wheel therefor.
The label transfer wheel of Rod includes a disc-like member adapted for rotation, the member having at least one radially projecting land portion or temporarily supporting individual labels thereon while the member turns. The land moves from ` a label receiving position to a label discharge position. The transfer wheel land has at least one vacuum supply channel in the surface thereof extending along the spine of the transfer wheel and a series of closely spaced cross grooves substantially at right angles to the supply channel and in open communication therewith for progressively drawing the labels into vacuum attachment with the surface of said land without buckling thereof.
~n Hubbard there is disclosed a label addressing ; device, and the claims are directed to a heat transfer wheelfor bringing labels having address information thereon into transfer contact with articles to be labeled. The heat transfer 23~
wheel of Hubbard includes a base member adapted ~or rotatable mounting; at least one label kransfer pad having a surface area adapted to support a label thereon; heatiny means for heating the pad surface area including at least one resistance type heater; an energizing circuit for said heater; means for mounting the pad on the base member in insulating relation thereto whereby to minimize loss of heat from the label transfer pad through the base member; means to permit vacuum to be applied to at least a portion of the pad sur~ace area ~` 10 so as to temporarily hold a label on the pad surface area and enable the base member to transport the label into contact with an article to be labeled, and control means for regulating operation of the heating means whereby to maintain the label transfer pad within a predetermined temperature range. The control means include a temperature responsive switching element in heat exchange relation with the label transfer pad and in series with the heater circuit, the switching element being adapted on a predetermined low temperature condition of the label transfer pad to close whereby to energize the heater and on a predetermined high temperature condition of the label transfer pad to open whereby to deenergize the heater; and signal light means to visibly indicate temperature conditions of the label transfer pad, the light means being in parallel circuit relationship with the switching element such that on opening of the switching element, the light means is activated and on closure of the switching elernent, a bypass circuit is established effectively rendering the light means inoperative.
Referring to Figures 1 and 2, during the interval while the label is carried on transfer wheel 10, heat from 3~
label transfer wheel 10 is relied upon to partiall~ melt, soften or tackify t~e heat activated adhesive on the bottom or back of the label where the label is an adhesive label.
It is during this interval that the printed matter partially melts, softens or tackifies, dependiny upon the type of ink, developer, toner and the like used to print information upon the label~ For example, xerographic toners well known in the art tend to tackify during this interval and partially ; adhere or stick to the surface of the heat transfer wheel ` ~ 10 causing "offset". This offset image prints out on subse~uent labels. Appropriate release fluid metered upon the surface of the heat transfer wheel prevents offset. In Figures 1 and 2 a label transfer pad or land of the heat transfer wheel when in contact with the heat transfer wheel meters ; 15 release fluid upon the surface of the pad. The release fluid prevents the sticky or softened print information from adhering ~ to the surface of the pad.
`; Although print wheel 10 having pad or land 30 thereon is illustrated in Figures 1 and 2 and only pad or land 30 contacts release fluid metering roll 80, as shown in Figure 2 when it is adjacent thereto during rotation, the present invention encompasses other common and well known heat transfer wheels including those having no prominent land, for example, a perfectl~ cylindrical wheel. As illustrated in Figure 1, metering roll 80 comprises a shaft 84 adapted for rotation and an outer layer of release fluid impregnated polymer such as silicone rubber covering the shaft. In Figure 1 the surface 86 of pad or land 30 is out-of-contact wi-th metering roll 80. However, as heat transfer wheel 10 rotates and pad 30 engages metering roll 80 which is adapted ~or rotation about , .
shaft 84, as illus-trated in Figure 2, metexing roll 80 rotates from frictional en~ayement with pad 30. This meters release -Eluid impregnated in layer 82 of metering roll 8a upon surface 86 and deposits a ~ilm of release fluid upon surface 86 preparing surface 86 for receiving another label from labeling head 22.
; Metering device 80 must be positioned rela-tive to the heat transfer wheel between the point where the label is deposited upon the article to be labeled and the point where a new label is supplied to the heat transfer wheel~
Although rolls are illustrated in the drawings, other meter-ing devices may be used in metering release fluid upon the heat transfer wheel including the pad or land. These include release fluid impregnated or carrying brushes, pads, wicks or belts, atomizer sprays, doctored rollers carrying release fluid from a sump and the like. Figure 3 is exem-plary of the release fluid impregnated roller where numeral 82 represents a silicone rubber impregnated with a release fluid. Figure 4 is exemplary of a doctored roller 89 mounted upon core 87, for example a silicone rubber roller upon a steel shaft, adapted for rotation relative to heat transfer wheel lOo Doctor blade-88 removes excess release fluid from roll 89. A supply of release fluid 85 is main.
tained in sump 81 and as roll 89 rotates in release fluid 85, release fluid is carried by roll 89 where the excess fluid is remo~ed by doctor blade 88 and release fluid is transferred from roll 89 to surface 85 of heat transfer 10.
A wickiny assembly is shown in ~.S. Patent No. 3,884,181 and U~S. Patent No. 3,79g,401~ Typical ofEset preventing fluid supply rolls and belts are disclosed in Canadian Patent 1,066,352 3~
Lassigned to the instant a~siynee.
Metering devices may be continuously rnaintained in contact with the surface of the heat contact wheel or there may be intermittent contact. Suitable camming devices (not shown) may be used to provide the intermikt~nt contact.
When the release fluid metering device is a roll adapted for rotation, the roll may be activated (rotate) due to frictional contact with the heat transfer roll as in Figure 2, or it may be driven by a motor (not shown~ or by the power drive of the labeling device.
The heat transfer wheels generally have bare metal surfaces which contact the lab~ls bearing printed information.
The softened or tackified print information has an increased tendency to stick to the bare m~tal. In accordance with the present invention only certain classes of release fluids applied to the bare metal surfaces reduce or eliminate the tendency of the softened or tackified print information to adhere to the bare metal surfaces. These are polymeric materials having functional groups thereon. The functional groups are generally carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof. Common release agents such as mineral oil and silicone oil (polydimethyl siloxane~ do not reduce or eliminate the offset problem and do not prevent the printed information from sticking or adhering to the bare metal surface of the heat transfer wheel.
In certain embodiments (not shown~ the heat transfer wheel can also be used to fix or fuse the printed information to the label substrate, for example, when the printed information is xero~raphic toner deposited upon -the label.
~he release fluid or agent prevents the toner ~rom adheriny . .
;23~i or sticking to the surface of the heat tr~nsEer wheel as descrihed above. In this embodiment, the heat transfer wheel serves as a heated surface to fix or fuse the print informa-tion on one side of the label substrate and to so~ten or tackify the adhesive material on the other side of the label substrate.
The polymeric fluids are operable in accordance with the present invention for metering on the surfaces of hea~
transfer wheels to form a film thereon only when the appro-priate functionality is present in the fluid. The polymericfluid, which has a suitable release function for the printed information on the label when the ink or toner is softened, forms an interfacial barrier between the metal or other material of the surface of the heat transfer wheel and the outer layer of the same fluid release material. In accord-ance with the present invention, ~his characteristic is foun~
in polymeric fluids which contain~ for example, such chemically reactive functional groups as carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and the like, - 20 and combinations thereof. These fluids are described in Canadian Serial No. 227,634, filed May 23, 1975, and assigned to the instant assignee.
The present invention encompasses polymeric fluids which are characterized by the above-described properties and which have the necessary functionality. By use of the term "functionality", is meant any material which is characterized by chemically reactive functional groups such as, for example, carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and the like, which interact with the surface of the heat transfer wheel. Such compounds or materials having the $unctionality are generally organic, but in certain cases compounds generally designated as inorganic materials may also be included in the class of materials which are operable ln accordance with the teachings o~ the present invention. Organosiloxane polymers, yenerally designated as inorganic polymers because of siloxane backbone structure comprising alternate silicon and oxygen atoms in the backbone, belong to that class of polymeric fluids which are operable in accordance with the present invention, as long as they contain the chemically reactive functional groups capable of interacting with the fuser member surface to ~orm a thermally stable in-terfacial barrier. The backbone polysiloxane chain itself (-Si-O-Si-O-)n is inorganic in nature, and because of this polysiloxane chain it is characteristically thermally and chemically stable. However, it may also be considered organic in nature because of the hydrocarbon content of the polymers.
The organic substituted polysiloxane derivatives, for example, the alkyl-substituted polyorganosiloxanes, havin~ the appropriate chemically reactive functionality have been found particularly useful in accordance with the present invention.
A typical polysiloxane is of the dialkyl type having the general formula:
~ ¦ C~3 whe~ein R represents a "spacer" group pendant from the polymer backbone and X representa a functional group. In preferred Z~6 embodiments R is an alkyl moiety h~ving about 1-8 carbon atoms, typically a propyl group (-C~2-CH2-CH2-). For a typical polymer having a one mole percent func~ional content, there is 1 a moiety for every 99 b's. If the functional group content is 2 mole percent, there is an average of 2 a moieties for every 98 b moieties. In a preferred embodiment, when a is an integer from about 1 to about 3, b may be an integer ~rom about 50 to about 600.
The R spacer groups may all be similar, for example, methyl, ethyl or propyl, or they may be mixtures of alkyl groups, for example, mixutres of propyl and butyl, or ethyl and propyl, and the like. In addition, t'ne R spacer group may be a straight chain, or it may be branched. The typical molecule shown in the general formula above comprises methyl groups substituted on the Si atoms in non-spacer group sites.
However, these non-spacer group sites may typically comprise general alkyl groups from about l to 6 carbons and mixtures thereof. Other groups may be substituted at these sites by one skilled in the art as long as the substituted groups do not interfere with the functional groups designated in the general ~ormula by X. The -R-X groups may be randomly positioned in the molecule to provide the functional groups critical in the release agents, processes and devices of the present invention. X, which represents the critical functional groups, is typically carboxy, hydroxy, epoxy, amino, isocyanate, mercapto or thioether. Alternatively or in addition, the functional groups (X) may be located on spacer groups (R) at terminal sites on the molecule, i.e., the molecule may be "end-capped" by the functional groups.
Other fluids whlch have been found operable in accordance with the present invention include those polymers which are fluid at operating temperatures and which have the designated functionality. For example, polyethylene polymers having any of the above-described functional groups, polypropylene having any of the above-described functional groups, polyisobutylene having any of the above-described functional groups, and the like, may be used in accordance with the present invention. Other examples of organic polymers which may be used in accordance with the present invention are the vinyl polymers having ~unctional groups, for example, polystyrene with carboxylic groups, polystyrene with amino groups, polystyrene with hydroxyl groups, and the like. Other homopolymers and copolymers may also be used, for example, copolymers of ethylene and acrylic acid, eth,vlene and methacrylic acid, propylene and acrylic acid, propylene and methacrylic acid, isobutylene and acrylic acid, isobutylene and methacrylic acid, ethylene and acrylamide, ethylene and methacrylamide and homopolymers and copolymers of 2-cyanoethyl acrylate.
Other polymeric fluids having chemically reactive functional groups which may be used in accordance with the present invention, are those materials which have the above-described characteristics when metered or coated upon a heat transfer wheel surface, examples of which are f~nctional group-substituted biphenyls and functional group-substituted polyphenyl ethers, for example, functional groups such as carboxy, hydroxy, epoxy, amino, isocyanate, thioether and mercapto.
Although concentrations of functional groups in the polymeric fluids greater than 10 mole percent may be utilized in accordance with the present inventi~n, there .
~3~23~
~enerally is no ~dv~n~aye in utilizing concen~ra~ions higher than 10 mole percent. Functional groups in concentrations even as low as about 0.2 functional groups per molecule on average have produced suitable results. To treat the surface of a heat transfer wheel by applying at least one polymeric fluid containing chemically reactive functional groups, one skilled in the art can adjust the concentration o-f the ~ functionality of the polymeric fluids to provide optimum ; release of the softened or tackified printed label information.
As used herein, "printed label in~ormation" refers to the print or toner or other visible colorin~ material or pigment on the surface of the label substrate. "Label substrate" refers to the paper, plastic, film or other material bearing the information and is distinguished from the article substrate to which ~he label is adhered, applied or secured.
The modes in which the release agents of the present invention are utilized are those wherein the coating or film is continuously or intermittently applied to the surface of the heat transfer wheel. The polymeric fluid having ` 20 functional groups therein may be applied to the heat transfer wheel by any of the standard or conventional methods or devices ~ known to those skilled in the art, and include application by `~ brushes, by spraying, by metering from a sump, by application from a wiper blade or wiper comprising the polymeric fluid having the functional groups therein, by applying from a suitable sump, by applying from a wick, by padding, and the like.
The polymeric release material may also be applied in the form of a solid which becomes fluid at opera-ting temperatures, for example, a block of the polymer having 23~
suitable functional groups may rub against the heated surface oE the heat transfer wheel to apply a film of the polymer on the heat transfer wheel. The polymeric release agent may also be applied in conjunction with a cutting or dilution agent with which it is miscible, that is, as two or more miscible components. ~n example of this embodiment is a mixture of the polydimethylsiloxane having functional mercapto groups attached to a propyl spacer group mixed with the polydimethylsiloxane (silicone oil) with which it is miscible and which acts as a dilution agent. The release agents or fluids of the present invention may also be applied as a single component to provide both the interfacial barrier and the release surface.
The fluid must be applied in an amount sufficient to cover the surface with at least a continuous low surface energy film in order to provide the heat transfer wheel with a surface which not only releases the printed label information heated by the wheel or pad thereon but also with an amount which will prevent the printed information from contacting the surface of the fuser member. Generally, in accordance with the objects of the present invention, the amount sufficient to cover the surface must be that amount which will maintain a thickness of the fluid in a range of submicron to microns and is preferably from about 0.5 micron to about lO microns in thickness.
The polymeric fluids having chemichlly reactive functional groups which are applied to the heat transfer wheel must not be curahle to the extent that they Eorm a soli~l or gel at operating temperatures for reasonable periods oE time.
The reasonable time is dependent upon khe labeling volume q~:Z3~6 of the device, and a reasonable period of time is at least about 200 hours and may be l,ooo to ~,ooo hours or longer.
The operating temperatures may vary from about 40C -to about 500~C, the preerred operating ranc;e being ~he amount of heat necessary to soften or tackify the adhesive on the label sufficiently 50 that it will adhere to a substrate.
The present invention may be used on the heat trans-fer wheel regardless of the type of ink, toner, pigment or other colored material used to provide the printed label information. However, it is especially useful when the printed label information on the side ofthe label adjacent the surface of the heat trans~er wheel is a heat softenable or heat-tackifiable coloring or printing material such as xerographic toner. Typical toners available for this pur-pose are well known in the ark. For example, a copolymerized mixture of styrene or a blend of styrene monologs with 10-40 percent (by weight) of one or more methacrylate esters selected from the group consisting of ethyl, propyl and butyl methacrylates as described in U.S.
Z0 Patent No. 3,079,342 may be used. Typical toner materials include gum copal, gum sandarac, rosin, asphaltum~
pilso~ite, phenol formaldehyde resins, rosin-modified phenol formaldehyde resins, methacrylic resins, polystyrene resins, polypropylene resins, epoxy resins, polyethylene resins and mixtures thereof. Among other patents describ-ing thermoplastic electroscopic toner compositions which are used to provide printed label information are U.S.
Patent ~o. 2~659,670 to Copley; U.S. Patent No. 7,754,408 to ~andrigan; U~S. Patent No. 3,079,342 to Insalaco; U.S.
Patent Reissue No. 25,136 to Carlson and U.S. Patent Wo.
This invention relates to article labeling machines, and more particularly, to reIease agents and applicator devices ~or applying release agents upon heat transfer wheels for use with article labeling machines.
Certain automatlc addressing and labeling machines for addressing or labeling arkicles, for example envelopes, utilize a rotatable, heated transer wheel to carry the address-bearing iteml normally referred to as a label, into physical contact with the article being addressed. The addressing or labeling machine incorporates suitable article transport means to bring the articles, one at a time, into operative position with the label transfer wheel.
In some applications, the labels themselves are physically attached to the articles and in this type of application, the labels carry a heat activated adhesive on their underside to enable the labels to be secured to the articles. During the relatively short interval while the label is borne by the label transfer wheel from the label supply point to the point where the label is transferred to the article, the trans~er wheel must heat the label sufficiently to activate the adhesive.
In effecting the aforedescribed transfer and adhesion of the label to articl~s, the heat input to the label supporting pad or surfac~ o~ the tran~fer wheel, which in turn is transmitted ; to the label itseI~, is critical. If too little heat is pro~ided, the label may not adhere to the article. On the other hand, too much heat ~ay result in the label sticking to the heat wheeI, incomplete adhesion o~ the label to the substrate or damage to the labeI.
The address or other label information carried upon the label is frequently printed upon the label with toners or inks which tackify or otherwise activate the ink or toner.
For example, when xerographic printing techniques are used to print label information, the toners used to make the label information visible by well-known xerographic imaging techniques; often tackify when subjected to the heat which activates the adhesive. This causes the label information to offset upon the surface of the heated transfer wheel and thereby causes a ghost image of the label information to appear on at least the next succeeding label. This offset phenomenon is a well-known term and problem charac-teristic of the xerographic art and is defined in the same erms herein. This problem is even more acute because the bare metal heated surface of the heat transfer wheel conkacts the label information side of the label.
_UMM~RY OF ~HE INVENTIOI`I
It is an object of an aspect of this invention to provide an improved article addressing machine.
; 20 It is an object of an aspect of this invention to provide an improved heat transfer wheel for article addressing machines.
It is an object of an aspect of this invention to provide a device and method for preventing the offset of - 25 label information upon the heated surface of heat transfer wheels in article addressing machines.
An object of an aspect of this invention is to ;~ provide a device and me~hod for preventing the offset of label information and improviny the release of address labels having label information printed thereon from the heated bare metal surface of the heat transfer wheel in an article addressing machine.
These and other objects are accomplis~led by applying a film of release agent comprising a polymer having functional groups on the surface of the heat transfer wheel so that there is a film of the release agent on the surface of that portion of the heat transfer wheel which contacts the label, when the label contacts the heat transfer wheel.
~n ~pec~ ~
In accordance with~the piesent invention, there is provided a method of applying labels having heat activated adhesive on one side and printed label information on the other side to a substrate by means of a heat transfer wheel in an article addressing machine comprising forming a film of a release agent for the printed label information on the surface of the heat transfer wheel. In those embodiments where a heated pad is provided on the heat transfer wheel, then the release agent is applied to the surface of the heated pad which contacts the side of the label having printed label information thereon, and as used herein, the -terminology heat transfer wheel encompasses a rotatably mounted base member having at least one heated label transfer pad thereon.
The release agent applied to the heat transfer wheel comprises a polymer having functional groups thereon.
The functional groups include carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof.
The polymer having functional groups is fluid (liquid) at the temperature of the heat transfer wheel.
After the filrn is formed on the surface of the heat transfer wheel, the side of the label having printed label - information thereon contacts the heat transfer wheel to soften or activate the adhesi~e on the other side of the label. Thus, the heat of the heat transfer wheel must be . ' ' ~ "' ~ , suf~icient to so~ten, tacki~y or ac~i~ate ~he a~hesive sufficiently to cause the adhesive to stick to the substrate to which it is appliea. ~any of the inks, toners and/or developers used to print the label information also soften or tackify when heated by the heat transfer wheel. This causes a part of the printed label information to stick to the heat trans~er wheel. A portion of this information remains on the surface of the heat transfer wheel when the label is separated therefrom and applied to the substrateO
This information remaining on the heat transfer wheel prints out on the next subsequent label forming a "ghost" or residual or "offset" image. By applying the film of release agent comprising a polymer having functional groups thereon in , accordance with the present invention, this problem of ; 15 offsetting or printing of a "ghost" or residual image on the next successive label is eliminated.
After the adhesive on the back side of the label, that is, on the side of the label opposite the printed label information, is sufficiently softened by the heat ` 20 supplied h~ the heat transfer wheel so that the adhesive is "active" or sticky enough to adhere to the substrate to which it is to be applied, the adhesive side of the label is ` brought into contact with the substrate and thereafter allowed to cool on the substrate. The heat transfer wheel presses the label having the heated adhesive thereon against the substrate, and the label is released from the heat transfer wheel having the release agent thereon. The label then cools to ambient and the softened adhesive and printed label information hardens, that is, they return to their non-softened state.
9;~:3~
In accordance with another aspect of this invention there is providecl in an article labeling device of the type having a heat transfer wheel for transferring a printed label onto an article, at least a part of said wheel having heating means for contacting and heating the label to activate adhesive on the labeI to enable the label to be secured to the article, the improvement comprising means for metering a release fluid on at least that portion of the wheel which contacts and heats the label. One side of the label contains a heat~softenable adhesive and the other side of the label contains the printed information, both of which are applied to the label prior to contact with the heat transfer wheel. The release fluid metered on the heat transfer wheel must be a fluid which prevents or substan-tially eliminates the "offset" problem discussed above.
Other objects and-features of the invention will be apparent from the following description and drawings.
Figure l is a side elevational view of an address-ing machine incorporating a typical release fluid met0ring device for metering release fluid on the heat transfer wheel in accordance with the present invention, the metering device being out-of-contact with the heat transfer wheel in the illustrated position.
Figure 2 is a side eIevational view of an address-ing machine incorporating a typical release fluid metering device for metering release fluid on the heat transfer wheel wherein the metering device contacts a label transfer g~36 device on the heat transfer wheel in the position illustrated.
Figure 3 is an enlarged side elevational view of a typical release fluid metering device in contact with a heat transfer wheel.
Figure 4 is a side elevational view of another typical release fluid metering device in contact with a heat transfer wheel.
DESCRIPTION OF THE 3?R3~FERRED: EMBOD~IMENTS
Referring to Figures 1 and 2 of the drawings, there is shown an exemplary automatic addressing machine 5 incorpo-rating label transfer wheel 10 and the release fluid metering device 80 of the present invention. Addressing machine 5 ~` includes a housing or cover 9, parts of which have beenbroken away in Figures 1 and 2 to show the construction of certain operating components therewithin. Addressing machine 5 has an article supply magazine 12 within which articles to be labeled are stacked, the walls 13 thereof being adjustable to accommodate articles of varying sizes. Article conveyor , 14 is employed to move articles discharged in seriatim from magazine 12, under gate 15 and pinch roller 16, past label transfer wheel 10 where the labels are transferred to the articles. The article conveyor 14 comprises one or more ; endless belts 17, supported by drive and idler rollers 18 and 19 respec-tively. Roller 18 is driven by suitable motor means (not shownl in the direction shown by the solid line arrow in Figures 1 and 2.
Labels are supplied to head 22 of addressing machine 5 from a suitable source, normally in the ~orm of an uncut sheet (not shown) having multiple label rows. Labeling head 22 includes suitable means (not shown) to advance the label Z3i i sheet forward as required to a guillotine type knife 23 which serves to cut the label supply sheet transversely into strips of several labels each. The strips rest in a downwardly inclined chute-like member 24 and are advanced therealong in the direction of transfer wheel 10 by intermittently driven pinch roll pair 25 to knife and anvil pair 26.
Knife and anvil pair 26 cooperate to cut the strip into individual labels which are discharged therefrom onto surface 86 o~ pad or land 30 of transfer wheel 10 as land 30 comes opposite the knife and anvil pair 26 during rotation of wheel 10. From there, wheel 10, which rotates in the directio~ shown by the solid line arrow of Figures 1 and 2, carries the label into physical contact with the articles being labeled as the articles move therebelow on conveyor 14.
It is understood that the several label supply components of labeling head 22 aforedescribed are operated in timed relationship with one another and with transfer wheel 10 and article transport 14 to assure the requisite supply of labels to transfer wheel 10 as required.
To assure the requisite pressure contact between the labels on surface 86 or pad or land 30 of transfer wheel 10 with the articles on transport 14, there is provided opposite transfer wheel 10, a support roller 28 for transport belt 17. Roller 28 is rotated in the direction shown by the solid line arrow in Figures 1 and 2 from the addressing machine motor (not shown). Although it is not always necessary, vacuum is used in the embodiments of Figures 1 and 2 to provide vacuum to land 30 for progressively drawing the ]abels into vacuum at~achment with surface 86 of pad or land 30.
Numeral 75 represents several vacuum lines used in the preferred embodiment illustrated~ The surface of the land, pad or heat transfer wheel which contacts and heats the adhesive on the label may be fabricated from any suitable material including aluminum, anodized aluminum, steel, nickel, copper, beryllium, silver, gold and the like and alloys of the foregoing.
Various labeling devices and their operation including the printing of the labels are well known in the art. Representative of these devices and for the purpose of illustration onl~ are the disclosures of Rod in U.S~
Patent No. 3,894,909 and of Hubbard in U.S. Patent No. 3,660,208, both references being incorporated herein by reference. These references illustrate the elements of labeling devices.
In Rod there is disclosed a label addressing device, and the claims cover an improved label transfer wheel therefor.
The label transfer wheel of Rod includes a disc-like member adapted for rotation, the member having at least one radially projecting land portion or temporarily supporting individual labels thereon while the member turns. The land moves from ` a label receiving position to a label discharge position. The transfer wheel land has at least one vacuum supply channel in the surface thereof extending along the spine of the transfer wheel and a series of closely spaced cross grooves substantially at right angles to the supply channel and in open communication therewith for progressively drawing the labels into vacuum attachment with the surface of said land without buckling thereof.
~n Hubbard there is disclosed a label addressing ; device, and the claims are directed to a heat transfer wheelfor bringing labels having address information thereon into transfer contact with articles to be labeled. The heat transfer 23~
wheel of Hubbard includes a base member adapted ~or rotatable mounting; at least one label kransfer pad having a surface area adapted to support a label thereon; heatiny means for heating the pad surface area including at least one resistance type heater; an energizing circuit for said heater; means for mounting the pad on the base member in insulating relation thereto whereby to minimize loss of heat from the label transfer pad through the base member; means to permit vacuum to be applied to at least a portion of the pad sur~ace area ~` 10 so as to temporarily hold a label on the pad surface area and enable the base member to transport the label into contact with an article to be labeled, and control means for regulating operation of the heating means whereby to maintain the label transfer pad within a predetermined temperature range. The control means include a temperature responsive switching element in heat exchange relation with the label transfer pad and in series with the heater circuit, the switching element being adapted on a predetermined low temperature condition of the label transfer pad to close whereby to energize the heater and on a predetermined high temperature condition of the label transfer pad to open whereby to deenergize the heater; and signal light means to visibly indicate temperature conditions of the label transfer pad, the light means being in parallel circuit relationship with the switching element such that on opening of the switching element, the light means is activated and on closure of the switching elernent, a bypass circuit is established effectively rendering the light means inoperative.
Referring to Figures 1 and 2, during the interval while the label is carried on transfer wheel 10, heat from 3~
label transfer wheel 10 is relied upon to partiall~ melt, soften or tackify t~e heat activated adhesive on the bottom or back of the label where the label is an adhesive label.
It is during this interval that the printed matter partially melts, softens or tackifies, dependiny upon the type of ink, developer, toner and the like used to print information upon the label~ For example, xerographic toners well known in the art tend to tackify during this interval and partially ; adhere or stick to the surface of the heat transfer wheel ` ~ 10 causing "offset". This offset image prints out on subse~uent labels. Appropriate release fluid metered upon the surface of the heat transfer wheel prevents offset. In Figures 1 and 2 a label transfer pad or land of the heat transfer wheel when in contact with the heat transfer wheel meters ; 15 release fluid upon the surface of the pad. The release fluid prevents the sticky or softened print information from adhering ~ to the surface of the pad.
`; Although print wheel 10 having pad or land 30 thereon is illustrated in Figures 1 and 2 and only pad or land 30 contacts release fluid metering roll 80, as shown in Figure 2 when it is adjacent thereto during rotation, the present invention encompasses other common and well known heat transfer wheels including those having no prominent land, for example, a perfectl~ cylindrical wheel. As illustrated in Figure 1, metering roll 80 comprises a shaft 84 adapted for rotation and an outer layer of release fluid impregnated polymer such as silicone rubber covering the shaft. In Figure 1 the surface 86 of pad or land 30 is out-of-contact wi-th metering roll 80. However, as heat transfer wheel 10 rotates and pad 30 engages metering roll 80 which is adapted ~or rotation about , .
shaft 84, as illus-trated in Figure 2, metexing roll 80 rotates from frictional en~ayement with pad 30. This meters release -Eluid impregnated in layer 82 of metering roll 8a upon surface 86 and deposits a ~ilm of release fluid upon surface 86 preparing surface 86 for receiving another label from labeling head 22.
; Metering device 80 must be positioned rela-tive to the heat transfer wheel between the point where the label is deposited upon the article to be labeled and the point where a new label is supplied to the heat transfer wheel~
Although rolls are illustrated in the drawings, other meter-ing devices may be used in metering release fluid upon the heat transfer wheel including the pad or land. These include release fluid impregnated or carrying brushes, pads, wicks or belts, atomizer sprays, doctored rollers carrying release fluid from a sump and the like. Figure 3 is exem-plary of the release fluid impregnated roller where numeral 82 represents a silicone rubber impregnated with a release fluid. Figure 4 is exemplary of a doctored roller 89 mounted upon core 87, for example a silicone rubber roller upon a steel shaft, adapted for rotation relative to heat transfer wheel lOo Doctor blade-88 removes excess release fluid from roll 89. A supply of release fluid 85 is main.
tained in sump 81 and as roll 89 rotates in release fluid 85, release fluid is carried by roll 89 where the excess fluid is remo~ed by doctor blade 88 and release fluid is transferred from roll 89 to surface 85 of heat transfer 10.
A wickiny assembly is shown in ~.S. Patent No. 3,884,181 and U~S. Patent No. 3,79g,401~ Typical ofEset preventing fluid supply rolls and belts are disclosed in Canadian Patent 1,066,352 3~
Lassigned to the instant a~siynee.
Metering devices may be continuously rnaintained in contact with the surface of the heat contact wheel or there may be intermittent contact. Suitable camming devices (not shown) may be used to provide the intermikt~nt contact.
When the release fluid metering device is a roll adapted for rotation, the roll may be activated (rotate) due to frictional contact with the heat transfer roll as in Figure 2, or it may be driven by a motor (not shown~ or by the power drive of the labeling device.
The heat transfer wheels generally have bare metal surfaces which contact the lab~ls bearing printed information.
The softened or tackified print information has an increased tendency to stick to the bare m~tal. In accordance with the present invention only certain classes of release fluids applied to the bare metal surfaces reduce or eliminate the tendency of the softened or tackified print information to adhere to the bare metal surfaces. These are polymeric materials having functional groups thereon. The functional groups are generally carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof. Common release agents such as mineral oil and silicone oil (polydimethyl siloxane~ do not reduce or eliminate the offset problem and do not prevent the printed information from sticking or adhering to the bare metal surface of the heat transfer wheel.
In certain embodiments (not shown~ the heat transfer wheel can also be used to fix or fuse the printed information to the label substrate, for example, when the printed information is xero~raphic toner deposited upon -the label.
~he release fluid or agent prevents the toner ~rom adheriny . .
;23~i or sticking to the surface of the heat tr~nsEer wheel as descrihed above. In this embodiment, the heat transfer wheel serves as a heated surface to fix or fuse the print informa-tion on one side of the label substrate and to so~ten or tackify the adhesive material on the other side of the label substrate.
The polymeric fluids are operable in accordance with the present invention for metering on the surfaces of hea~
transfer wheels to form a film thereon only when the appro-priate functionality is present in the fluid. The polymericfluid, which has a suitable release function for the printed information on the label when the ink or toner is softened, forms an interfacial barrier between the metal or other material of the surface of the heat transfer wheel and the outer layer of the same fluid release material. In accord-ance with the present invention, ~his characteristic is foun~
in polymeric fluids which contain~ for example, such chemically reactive functional groups as carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and the like, - 20 and combinations thereof. These fluids are described in Canadian Serial No. 227,634, filed May 23, 1975, and assigned to the instant assignee.
The present invention encompasses polymeric fluids which are characterized by the above-described properties and which have the necessary functionality. By use of the term "functionality", is meant any material which is characterized by chemically reactive functional groups such as, for example, carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and the like, which interact with the surface of the heat transfer wheel. Such compounds or materials having the $unctionality are generally organic, but in certain cases compounds generally designated as inorganic materials may also be included in the class of materials which are operable ln accordance with the teachings o~ the present invention. Organosiloxane polymers, yenerally designated as inorganic polymers because of siloxane backbone structure comprising alternate silicon and oxygen atoms in the backbone, belong to that class of polymeric fluids which are operable in accordance with the present invention, as long as they contain the chemically reactive functional groups capable of interacting with the fuser member surface to ~orm a thermally stable in-terfacial barrier. The backbone polysiloxane chain itself (-Si-O-Si-O-)n is inorganic in nature, and because of this polysiloxane chain it is characteristically thermally and chemically stable. However, it may also be considered organic in nature because of the hydrocarbon content of the polymers.
The organic substituted polysiloxane derivatives, for example, the alkyl-substituted polyorganosiloxanes, havin~ the appropriate chemically reactive functionality have been found particularly useful in accordance with the present invention.
A typical polysiloxane is of the dialkyl type having the general formula:
~ ¦ C~3 whe~ein R represents a "spacer" group pendant from the polymer backbone and X representa a functional group. In preferred Z~6 embodiments R is an alkyl moiety h~ving about 1-8 carbon atoms, typically a propyl group (-C~2-CH2-CH2-). For a typical polymer having a one mole percent func~ional content, there is 1 a moiety for every 99 b's. If the functional group content is 2 mole percent, there is an average of 2 a moieties for every 98 b moieties. In a preferred embodiment, when a is an integer from about 1 to about 3, b may be an integer ~rom about 50 to about 600.
The R spacer groups may all be similar, for example, methyl, ethyl or propyl, or they may be mixtures of alkyl groups, for example, mixutres of propyl and butyl, or ethyl and propyl, and the like. In addition, t'ne R spacer group may be a straight chain, or it may be branched. The typical molecule shown in the general formula above comprises methyl groups substituted on the Si atoms in non-spacer group sites.
However, these non-spacer group sites may typically comprise general alkyl groups from about l to 6 carbons and mixtures thereof. Other groups may be substituted at these sites by one skilled in the art as long as the substituted groups do not interfere with the functional groups designated in the general ~ormula by X. The -R-X groups may be randomly positioned in the molecule to provide the functional groups critical in the release agents, processes and devices of the present invention. X, which represents the critical functional groups, is typically carboxy, hydroxy, epoxy, amino, isocyanate, mercapto or thioether. Alternatively or in addition, the functional groups (X) may be located on spacer groups (R) at terminal sites on the molecule, i.e., the molecule may be "end-capped" by the functional groups.
Other fluids whlch have been found operable in accordance with the present invention include those polymers which are fluid at operating temperatures and which have the designated functionality. For example, polyethylene polymers having any of the above-described functional groups, polypropylene having any of the above-described functional groups, polyisobutylene having any of the above-described functional groups, and the like, may be used in accordance with the present invention. Other examples of organic polymers which may be used in accordance with the present invention are the vinyl polymers having ~unctional groups, for example, polystyrene with carboxylic groups, polystyrene with amino groups, polystyrene with hydroxyl groups, and the like. Other homopolymers and copolymers may also be used, for example, copolymers of ethylene and acrylic acid, eth,vlene and methacrylic acid, propylene and acrylic acid, propylene and methacrylic acid, isobutylene and acrylic acid, isobutylene and methacrylic acid, ethylene and acrylamide, ethylene and methacrylamide and homopolymers and copolymers of 2-cyanoethyl acrylate.
Other polymeric fluids having chemically reactive functional groups which may be used in accordance with the present invention, are those materials which have the above-described characteristics when metered or coated upon a heat transfer wheel surface, examples of which are f~nctional group-substituted biphenyls and functional group-substituted polyphenyl ethers, for example, functional groups such as carboxy, hydroxy, epoxy, amino, isocyanate, thioether and mercapto.
Although concentrations of functional groups in the polymeric fluids greater than 10 mole percent may be utilized in accordance with the present inventi~n, there .
~3~23~
~enerally is no ~dv~n~aye in utilizing concen~ra~ions higher than 10 mole percent. Functional groups in concentrations even as low as about 0.2 functional groups per molecule on average have produced suitable results. To treat the surface of a heat transfer wheel by applying at least one polymeric fluid containing chemically reactive functional groups, one skilled in the art can adjust the concentration o-f the ~ functionality of the polymeric fluids to provide optimum ; release of the softened or tackified printed label information.
As used herein, "printed label in~ormation" refers to the print or toner or other visible colorin~ material or pigment on the surface of the label substrate. "Label substrate" refers to the paper, plastic, film or other material bearing the information and is distinguished from the article substrate to which ~he label is adhered, applied or secured.
The modes in which the release agents of the present invention are utilized are those wherein the coating or film is continuously or intermittently applied to the surface of the heat transfer wheel. The polymeric fluid having ` 20 functional groups therein may be applied to the heat transfer wheel by any of the standard or conventional methods or devices ~ known to those skilled in the art, and include application by `~ brushes, by spraying, by metering from a sump, by application from a wiper blade or wiper comprising the polymeric fluid having the functional groups therein, by applying from a suitable sump, by applying from a wick, by padding, and the like.
The polymeric release material may also be applied in the form of a solid which becomes fluid at opera-ting temperatures, for example, a block of the polymer having 23~
suitable functional groups may rub against the heated surface oE the heat transfer wheel to apply a film of the polymer on the heat transfer wheel. The polymeric release agent may also be applied in conjunction with a cutting or dilution agent with which it is miscible, that is, as two or more miscible components. ~n example of this embodiment is a mixture of the polydimethylsiloxane having functional mercapto groups attached to a propyl spacer group mixed with the polydimethylsiloxane (silicone oil) with which it is miscible and which acts as a dilution agent. The release agents or fluids of the present invention may also be applied as a single component to provide both the interfacial barrier and the release surface.
The fluid must be applied in an amount sufficient to cover the surface with at least a continuous low surface energy film in order to provide the heat transfer wheel with a surface which not only releases the printed label information heated by the wheel or pad thereon but also with an amount which will prevent the printed information from contacting the surface of the fuser member. Generally, in accordance with the objects of the present invention, the amount sufficient to cover the surface must be that amount which will maintain a thickness of the fluid in a range of submicron to microns and is preferably from about 0.5 micron to about lO microns in thickness.
The polymeric fluids having chemichlly reactive functional groups which are applied to the heat transfer wheel must not be curahle to the extent that they Eorm a soli~l or gel at operating temperatures for reasonable periods oE time.
The reasonable time is dependent upon khe labeling volume q~:Z3~6 of the device, and a reasonable period of time is at least about 200 hours and may be l,ooo to ~,ooo hours or longer.
The operating temperatures may vary from about 40C -to about 500~C, the preerred operating ranc;e being ~he amount of heat necessary to soften or tackify the adhesive on the label sufficiently 50 that it will adhere to a substrate.
The present invention may be used on the heat trans-fer wheel regardless of the type of ink, toner, pigment or other colored material used to provide the printed label information. However, it is especially useful when the printed label information on the side ofthe label adjacent the surface of the heat trans~er wheel is a heat softenable or heat-tackifiable coloring or printing material such as xerographic toner. Typical toners available for this pur-pose are well known in the ark. For example, a copolymerized mixture of styrene or a blend of styrene monologs with 10-40 percent (by weight) of one or more methacrylate esters selected from the group consisting of ethyl, propyl and butyl methacrylates as described in U.S.
Z0 Patent No. 3,079,342 may be used. Typical toner materials include gum copal, gum sandarac, rosin, asphaltum~
pilso~ite, phenol formaldehyde resins, rosin-modified phenol formaldehyde resins, methacrylic resins, polystyrene resins, polypropylene resins, epoxy resins, polyethylene resins and mixtures thereof. Among other patents describ-ing thermoplastic electroscopic toner compositions which are used to provide printed label information are U.S.
Patent ~o. 2~659,670 to Copley; U.S. Patent No. 7,754,408 to ~andrigan; U~S. Patent No. 3,079,342 to Insalaco; U.S.
Patent Reissue No. 25,136 to Carlson and U.S. Patent Wo.
2,788,288 to ~heinfrank et al.
In the following examples, silicone rubber rolls are impregnated with fluids and inserted in a system similar to that shown in Figures 1 and 2. The fluid-impregnated roll is similar to the roll designated by numeral 80 in Figure 3.
Address labels on a paper substrate are printed xerographically, and the printed label information thereon is a heat-softenable toner similar to the toner described above and designated by the trade designation Xerox 660 Toner. Xerox is a registered trademark of Xerox Corporation.
The xerographically printed labels are placed in a labeling device similar to the one shown in Figures 1 and 2.
The labels have a heat-softenable adhesive backing for securing them to articles. Paper envelopes are passed under the bare metal heat transfer wheel having a copper-surfaced pad thereon, and the labels having softened adhesive backings are secured to the paper envelopes.
In tests run without a release fluid and without a release fluid metering device, there was offsetting of the printed label information (toner) upon the heat transfer wheel, and the offset image was transferred from the wheel to the next successive label.
In tests run ~-ith a metering device as shown in Figure 3 impregnated with silicone oil, there is offsetting of the printed label information (toner) upon the heat transfer wheel even though silicone oil (non-functional polydimethyl siloxane) is metered on the wheel and formed a film thereon. This offset image (toner) on the wheel was then transferred to the next successive label and appeared as a ghost image thereon.
, :
In tests run with ~ metering device as shown in Figure 3 impregnated with a poly~imethyl siloxane having mercapto groups attached to a propyl spacer group, there was no offsetting of the printed label information (toner) upon the bare metal of the heat transfer wheel. The mercapto-functional polydimethyl siloxane had a molecular weight of 14,000, a viscosity of 275 centistokes, and a sulfur content of 0.18 sulfur groups/molecule. No "ghost" images appeared upon successive labels which contacted the heat transfer wheel.
In another example, conditions were identical except the mercapto-functional polydimethyl siloxane was diluted by adding 3 parts by volume Xerox Fuser Oil (poly-dimethyl siloxane). The sulfur content of the blend was 0.04 sulfur groups or atoms per molecule and the viscosity was 160 centistokes. There was no offset of the printed label ` upon the bare metal surfaced heat transfer wheel.
; As used herein, "offset" or "offsetting" is the transfer of printed label information (toner) from one substrate to another substrate and more specifically, from the substrate to which it is affixed as printed label information, for example, a label, to the surface of the heat transfer wheel. When printed label in~ormation (toner) contacts the heated heat transfer wheel, the toner liquifies, softens, tackifies or becomes molten, and in this state it has a tendency to split, part of the printed label information (toner) remaining on the label substrate and part of it transferring to the surface of the heat transfer wheel. This is known as "hot offset". Splitting of -the printed label information (toner) occurs when the cohesive forces holding ' ;23~
the viscous toner mass together, is less than the adhesive forces tending to offset it to a contacting surface such as heated transfer roll. Release failure occurs when there is a splitting of the image when the toner is softened and is sufficiently sticky to adhere to the surface of the heated transfer wheel which results in a partial or ghost image on the next label, producing what is referred to as an offset image.
While the invention has been described with respect to preferred embodiments, it will be apparent that certain modifications and changes can be made without departing from the spirit and scope of the invention, and therefore, it is intended that the foregoing disclosure be limited only by the claims appended hereto.
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: .
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In the following examples, silicone rubber rolls are impregnated with fluids and inserted in a system similar to that shown in Figures 1 and 2. The fluid-impregnated roll is similar to the roll designated by numeral 80 in Figure 3.
Address labels on a paper substrate are printed xerographically, and the printed label information thereon is a heat-softenable toner similar to the toner described above and designated by the trade designation Xerox 660 Toner. Xerox is a registered trademark of Xerox Corporation.
The xerographically printed labels are placed in a labeling device similar to the one shown in Figures 1 and 2.
The labels have a heat-softenable adhesive backing for securing them to articles. Paper envelopes are passed under the bare metal heat transfer wheel having a copper-surfaced pad thereon, and the labels having softened adhesive backings are secured to the paper envelopes.
In tests run without a release fluid and without a release fluid metering device, there was offsetting of the printed label information (toner) upon the heat transfer wheel, and the offset image was transferred from the wheel to the next successive label.
In tests run ~-ith a metering device as shown in Figure 3 impregnated with silicone oil, there is offsetting of the printed label information (toner) upon the heat transfer wheel even though silicone oil (non-functional polydimethyl siloxane) is metered on the wheel and formed a film thereon. This offset image (toner) on the wheel was then transferred to the next successive label and appeared as a ghost image thereon.
, :
In tests run with ~ metering device as shown in Figure 3 impregnated with a poly~imethyl siloxane having mercapto groups attached to a propyl spacer group, there was no offsetting of the printed label information (toner) upon the bare metal of the heat transfer wheel. The mercapto-functional polydimethyl siloxane had a molecular weight of 14,000, a viscosity of 275 centistokes, and a sulfur content of 0.18 sulfur groups/molecule. No "ghost" images appeared upon successive labels which contacted the heat transfer wheel.
In another example, conditions were identical except the mercapto-functional polydimethyl siloxane was diluted by adding 3 parts by volume Xerox Fuser Oil (poly-dimethyl siloxane). The sulfur content of the blend was 0.04 sulfur groups or atoms per molecule and the viscosity was 160 centistokes. There was no offset of the printed label ` upon the bare metal surfaced heat transfer wheel.
; As used herein, "offset" or "offsetting" is the transfer of printed label information (toner) from one substrate to another substrate and more specifically, from the substrate to which it is affixed as printed label information, for example, a label, to the surface of the heat transfer wheel. When printed label in~ormation (toner) contacts the heated heat transfer wheel, the toner liquifies, softens, tackifies or becomes molten, and in this state it has a tendency to split, part of the printed label information (toner) remaining on the label substrate and part of it transferring to the surface of the heat transfer wheel. This is known as "hot offset". Splitting of -the printed label information (toner) occurs when the cohesive forces holding ' ;23~
the viscous toner mass together, is less than the adhesive forces tending to offset it to a contacting surface such as heated transfer roll. Release failure occurs when there is a splitting of the image when the toner is softened and is sufficiently sticky to adhere to the surface of the heated transfer wheel which results in a partial or ghost image on the next label, producing what is referred to as an offset image.
While the invention has been described with respect to preferred embodiments, it will be apparent that certain modifications and changes can be made without departing from the spirit and scope of the invention, and therefore, it is intended that the foregoing disclosure be limited only by the claims appended hereto.
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Claims (19)
1. In an article labeling device of the type having a heat transfer wheel for transferring a printed label onto an article, at least a part of said wheel having heating means for contacting and heating the label to activate adhesive on the label to enable the label to be secured to the article, the improvement comprising means for metering a release fluid on at least that portion of the wheel which contacts and heats the label.
2. The device of Claim 1 further comprising a sump containing release fluid and means for conveying the release fluid from the sump to the wheel.
3. The device of Claim 2 wherein the means for conveying release fluid to the wheel is a wick.
4. The device of Claim 2 wherein the means for conveying release fluid to the wheel is a metering roll.
5. The device of Claim 1 wherein the means for metering is a roller impregnated with release fluid.
6. The device of Claim 5 wherein the release fluid comprises mercapto-functional polysiloxane fluid and the heat transfer wheel to which the fluid is applied has a bare metal surface.
7. A method of applying labels having heat activated adhesive on one side and printed label information on the other side to a substrate by means of a heat transfer wheel in an article addressing machine comprising:
(a) forming a film on the surface of the heat transfer wheel, said film being a release agent for the printed label information and comprising a polymer having functional groups thereon, said polymer being fluid at the temperature of the heat transfer wheel;
(b) contacting the side of the label having printed label information thereon with the heat transfer wheel having the release agent thereon to soften the adhesive;
(c) applying the adhesive side of the label to a substrate while the adhesive is softened; and (d) allowing the adhesive to cool.
(a) forming a film on the surface of the heat transfer wheel, said film being a release agent for the printed label information and comprising a polymer having functional groups thereon, said polymer being fluid at the temperature of the heat transfer wheel;
(b) contacting the side of the label having printed label information thereon with the heat transfer wheel having the release agent thereon to soften the adhesive;
(c) applying the adhesive side of the label to a substrate while the adhesive is softened; and (d) allowing the adhesive to cool.
8. The method of Claim 7 comprising continuously applying the polymer on the heat transfer wheel to maintain a film of the release agent thereon.
9. The method of Claim 7 wherein the reactive functional groups of the polymer are selected from the group consisting of carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof.
10. The method of Claim 7 wherein the polymer comprises polydialkyl siloxane having functional groups selected from the group consisting of carboxy, hydroxy, epoxy, amino, isocyanate, thioether, mercapto and combinations thereof.
11. The method of Claim 10 wherein the functional groups are substituted on the alkyl moiety of the dialkyl polysiloxane.
12. The method of Claim 7 further comprising a blend of the polymeric fluid having functional groups and at least one dilution agent which is miscible therewith.
13. The method of Claim 12 wherein the dilution agent is polydimethyl siloxane.
14. The method of Claim 7 wherein the heat transfer wheel has a bare metal surface.
15. The method of Claim 14 wherein the surface of the heat transfer wheel comprises copper.
16. The method of Claim 7 wherein the printed label information is thermoplastic electroscopic resin deposited on the label.
17. The method of Claim 7 wherein the polymer having reactive functional groups comprises a polysiloxane having the general formula:
wherein R represents an alkyl group pendant from the silicon atom, X represents a mercapto Group, a is an integer from 1 to 3 and b is an integer from 50 to 600.
wherein R represents an alkyl group pendant from the silicon atom, X represents a mercapto Group, a is an integer from 1 to 3 and b is an integer from 50 to 600.
18. The method of Claim 17 wherein the alkyl group has 1 to 8 carbon atoms.
19. The method of Claim 14 wherein the surface of the heat transfer wheel comprises aluminum.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US80259877A | 1977-06-02 | 1977-06-02 | |
| US802,598 | 1997-02-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099236A true CA1099236A (en) | 1981-04-14 |
Family
ID=25184172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA303,232A Expired CA1099236A (en) | 1977-06-02 | 1978-05-12 | Device and method for release of labels from label transfer wheels |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1099236A (en) |
| GB (1) | GB1603065A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10147753A (en) * | 1996-01-30 | 1998-06-02 | Ricoh Co Ltd | Method and apparatus for thermally activating heat-sensitive tacky adhesive label |
-
1978
- 1978-05-12 CA CA303,232A patent/CA1099236A/en not_active Expired
- 1978-05-30 GB GB2394178A patent/GB1603065A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1603065A (en) | 1981-11-18 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |