Abstract:
A receiver for receiving a water-based colorant image transferred by a stamp or the like, including an image receiving structure having a support; an information receiving layer which contains recorded information, such information receiving layer being formed over the support; and a clear hydrophobic protective layer formed over the information receiving layer; and a hydrophilic layer formed over the information receiving layer and selected so as to be able to receive a water-based colorant image.

Description:
FIELD OF THE INVENTION 
     The present invention relates to providing a water-based colorant image on a receiver having an information image. 
     BACKGROUND OF THE INVENTION 
     Heretofore images of high quality have been produced by thermal printers. In a typical thermal printer an image is formed in three passes. First a colorant patch having color such as yellow is placed in transfer relationship with a receiver and then the colorant patch is heated in a pattern corresponding to the yellow portion of an image to be completed. Thereafter, cyan and magenta portions of the image are formed in a similar fashion. The completed color image on the receiver is continuous tone and in many cases can rival photographic quality. 
     In one type of thermal printer which prints colored images, a donor contains a repeating series of spaced frames of different colored heat transferable colorants. Thermal colorant transfer printers offer the advantage of true “continuous tone” density transfer. This result is obtained by varying the energy applied to each heating element, yielding a variable density image pixel in the receiver. The donor is disposed between a receiver, such as coated paper, and a print head formed of, for example, a plurality of individual heating resistors. When a particular heating resistor is energized, it produces heat and causes colorant from the donor to transfer to the receiver. The density or darkness of the printed color colorant is a function of the energy delivered from the heating element to the donor. 
     Under common circumstances after an image is printed, a protective layer of material is coated in order to prevent damage to the image. Commonly-assigned U.S. Pat. No. 5,369,077 teaches that silicone block copolymers are added to the receiver and receiver overcoat to prevent sticking to the colorant patch. Though this effectively protects the image it hurts the ability to affix information carried by a water soluble inks or pigments, for example a rubber stamp mark. Rubber or polymer stamp marks normally consist of water soluble inks or pigments. Images produced using a thermal printing process provide a convenient method for creating images for use as identification, for example as passport and visa pictures and small pictures that are attached to school, job or club applications. When pictures are used for identification purposes, the pictures and the documents to which they are attached may require some type of official stamp. In most cases the stamp is an official seal made of rubber. The rubber stamp is used to apply the official seal to the document and picture. The marking medium is a water soluble ink or pigment that is readily absorbed by the material to which it is applied. In the case of thermal media during the printing process a protective transparent layer is coated that is water resistant thus making the adhesion of a rubber stamp impossible. Commonly-assigned U.S. Pat. No. 5,614,464 teaches the addition of perfluorinated alkyl sulfonamide ester copolymers to improve receiver writeability. This coating on the other hand may help the adherence of water based inks or dyes. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to produce a surface that will accept information carried in a water-based colorant as is the case of a rubber or polymer stamp. 
     The object is achieved by: a receiver for receiving a water-based colorant image transferred by a stamp or the like, comprising:
         (a) an image receiving structure having:
           (i) a support;   (ii) an information receiving layer which contains recorded information, such information receiving layer being formed over the support; and   (iii) a clear hydrophobic protective layer formed over the information receiving layer; and   
           (b) a hydrophilic layer formed over the information receiving layer and selected so as to be able to receive a water-based colorant image.       

     In a preferred embodiment of this invention the hydrophilic layer is provided by a gelatin or other material with similar surface properties formulated with the appropriate surfactants so that it can adhere to the clear hydrophobic protective layer. 
     In another embodiment of this invention the hydrophobic protective layer and the hydrophilic layer can be applied from patches on a donor element which also includes patches having colorants for forming the information image. 
     An advantage of the present invention is that the hydrophilic layer can be formed on a receiver which already has received an information image. 
     A feature of the invention is that the hydrophilic layer can readily receive water-based colorant images transferred from a rubber stamp. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a thermal printing apparatus which makes dye images in a receiver in accordance with the present invention; 
         FIG. 2  is a cross-sectional view of a receiver which is used in the apparatus of  FIG. 1 ; 
         FIG. 3  shows a strip of a typical colorant donor element in web format which can be used by the apparatus shown in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of a receiver which is used in the apparatus of  FIG. 1  showing a thermal printer coating assembly coating a receiver structure of the print; 
         FIG. 5  is a front view of a thermal printer with a coating assembly coating a receiver structure of the print; 
         FIG. 6  is a sectional view taken along the lines A—A of  FIG. 5 ; 
         FIG. 7  shows a side view of a rubber stamp applying a stamp image on the surface of the finished print; 
         FIG. 8  shows an image that the rubber stamp of  FIG. 7  has applied to on the surface of the finished print; and 
         FIG. 9  shows a strip of typical colorant donor element in web format having colorant patches, a clear hydrophobic patches and a clear hydrophilic patch. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1  where a thermal printer apparatus  10  employs receivers  12  and a colorant donor element  14  in the form of a web. Receivers  12 , in the form of a sheet is serially fed from a tray  16  to a print position by a conventional sheet feeding mechanism, not shown. The thermal printer apparatus  10  uses a colorant donor element  14  which typically employs a colorant that is a dye. Upon heating dye is transferred to a dye receiving element. However, pigments can also be used and the present invention is equally applicable when the printer apparatus is an ink jet printer. Because in any of these situations, a hydrophilic image from a stamp or the like is transferred to a hydrophilic layer as will be described below. 
     Now referring to  FIG. 2 , the receiver  12  is comprised of an image receiving structure  50  which includes a support  56 . The support  56  can be formed of paper or plastic such as polyethylene terephthlate or polyethylene napthhlate. Alternatively, it can be in the form of a web. Upon each support  56  will be an image receiving layer  60  for receiving colorant from the colorant donor element  14  to form information images. When dye is the colorant a barrier layer  58  is provided to prevent the dye from bleeding into the support  56 . In such a situation the image receiving layer  60  is formed on the barrier layer  58 . 
     Referring back to  FIG. 1 , in operation, a platen  18  is moved into print position by an actuator  20  pressing the receiver  12  against the colorant donor element  14 . Actuators are well known in the field and can be provided by a mechanical linkage, solenoid, and small piston arrangement or the like. The colorant donor element  14 , shown in  FIG. 3  as a web, includes a series of colorant patches. These colorant patches can be cyan, yellow, and magenta  64   a ,  64   b ,  64   c , respectively, and they are sequentially moved into image transferring relationship with the colorant donor element  14 . Each series of colorant patches  64   a-c  is followed by a protective coating patch  66  which is formed of a material that can form a clear hydrophobic protective layer  62 . 
     The colorant donor element  14  is driven along a path from a supply roller  24  onto a take-up roller  26  by a drive mechanism  28  coupled to the take-up roller  26 . The drive mechanism  28  includes a stepper motor which incrementally advances and stops the colorant donor element  14  relative to the receiver  12 . 
     A control unit  30  having a microcomputer converts digital signals corresponding to the desired image from a computer  32  to analog signals and sends them as appropriate to the optical system  38  which modulates the laser beam produced by a laser light source  34 . The laser light source  34  illuminates the colorant donor element  14  and heats such colorant donor element  14  to cause the transfer of colorant to the image receiving layer  60  of the image receiving structure  50 . This process is repeated until an information image is formed on each of the image receiving structures  50 . Alternatively, a plurality of donor resistive elements (not shown) which are in contact with the colorant donor element  14 . When a donor resistive element is energized it is heated which causes colorant to transfer from the colorant donor element  14  to the receiver  12  in a pattern to provide an information image. For a more complete description of this type of thermal printing apparatus reference is made to commonly assigned U.S. Pat. No. RE 33,260. Of course the process has to be repeated using the cyan, yellow and magenta patches  64   a-c  to complete the information image. An additional pass consists of transferring a clear hydrophobic protective layer  62 . 
     Now referring to  FIG. 4 , the image receiving layer  60  of the image receiving structure  50  has received an information image by the transference of the colorant donor element  14  using the thermal printer apparatus  10 . After the colorant donor element  14  has formed the information image, the clear hydrophobic protective layer  62  is transferred using the thermal printer apparatus  10 . As the image receiving structure  50 , exits the thermal printing apparatus  10  in the direction indicated by arrow  69  a hydrophilic mixture  70  such as a layer consisting of gelatin or other material with similar surface properties formulated with the appropriate surfactants such as Alkanol XC, Triton 200 or Aerosol OT is applied to the clear hydrophobic protective layer  62  via an applicator assembly  72  comprised of a reservoir  74 , an applicator  76  and a drive mechanism  78  to form a hydrophilic coating  80 . The applicator  76  can also apply other materials such as the synthetic polymers to provide the clear hydrophilic layer  80  which are selected from the group consisting of polyvinylpyrollidone (PVP), polyester ionomers, polyethylene oxide and copolymers of vinyl alcohol. 
     Now referring to  FIGS. 5 and 6  which show portions of a thermal printer  82  is equipped with an applicator assembly  72 . As the thermal print  84  exits the thermal printer  82  a hydrophilic mixture  70  including gelatin or other material with similar surface properties formulated with the appropriate surfactants is applied to the thermal print  84  via an applicator  76  and drive mechanism  78 . A drive mechanism (not shown) for the thermal printer  82  is used in conjunction with the drive mechanism  78  (see  FIG. 4 ) to drive the thermal print  84  through the applicator  76 . 
     Alternatively, a hydrophilic mixture  70  including gelatin or other material with similar surface properties formulated with the appropriate surfactants is applied to the clear hydrophobic protective layer  62  via an aerosol sprayer to form a hydrophilic coating  80 . 
     Still further in another embodiment, a hydrophilic mixture  70  including gelatin or other material with similar surface properties formulated with the appropriate surfactants is applied to the clear hydrophobic protective layer  62  via a roller to form a hydrophilic coating  80 . 
     Now referring to  FIG. 7 , a thermal print  84  is shown in a side view. A hydrophilic coating  80  has been applied to the clear hydrophobic protective layer  62  of the thermal print  84 . A rubber stamp  88  is used to apply an official seal  92  to the thermal print  84  as shown in  FIG. 8  having an information image  90 . The colorants applied by the rubber or polymer stamp  88  should of course be hydrophilic and they can be for example, dyes or pigments. The inks containing these colorants are well known in the art and are described in U.S. Pat. Nos. 5,672,198 and 4,469,464. 
     In another embodiment the colorant donor element  14 , shown in  FIG. 9  as a web, includes a series of colorant patches  64   a-c . These colorant patches can be cyan, yellow, and magenta  64   a ,  64   b ,  64   c , respectively, and they are sequentially moved into image transferring relationship with the colorant donor element  14 . Each series of colorant patches  64   a-c  is followed by a protective coating patch  66  which in turn is followed by a hydrophilic patch  110 . An additional pass includes transferring a hydrophilic patch  110 . The transferal of the hydrophilic patch  110  creates a clear hydrophilic layer  80  over the clear hydrophobic protective layer  62  of the thermal print  84 . 
     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10 
                 printer apparatus 
               
               
                   
                 12 
                 receiver 
               
               
                   
                 14 
                 colorant donor element 
               
               
                   
                 16 
                 tray 
               
               
                   
                 18 
                 platen 
               
               
                   
                 20 
                 actuator 
               
               
                   
                 24 
                 supply roller 
               
               
                   
                 26 
                 take-up roller 
               
               
                   
                 28 
                 drive mechanism 
               
               
                   
                 30 
                 control unit 
               
               
                   
                 32 
                 computer 
               
               
                   
                 34 
                 laser light source 
               
               
                   
                 38 
                 optical system 
               
               
                   
                 50 
                 image receiving structure 
               
               
                   
                 56 
                 support 
               
               
                   
                 60 
                 image receiving layer 
               
               
                   
                 62 
                 hydrophobic protective layer 
               
               
                   
                  64a 
                 cyan patch 
               
               
                   
                  64b 
                 yellow patch 
               
               
                   
                  64c 
                 magenta patch 
               
               
                   
                 66 
                 protective coating patch 
               
               
                   
                 69 
                 arrow 
               
               
                   
                 70 
                 hydrophilic mixture 
               
               
                   
                 72 
                 applicator assembly 
               
               
                   
                 74 
                 reservoir 
               
               
                   
                 76 
                 applicator 
               
               
                   
                 78 
                 drive mechanism 
               
               
                   
                 80 
                 hydrophilic coating 
               
               
                   
                 82 
                 thermal printer 
               
               
                   
                 84 
                 thermal print 
               
               
                   
                 88 
                 rubber stamp 
               
               
                   
                 90 
                 information image 
               
               
                   
                 110  
                 hydrophilic patch