Abstract:
A simple and convenient apparatus and method for producing stamps using a photo polymer. A sandwich is constructed which includes a first ridged UV clear panel, a translucent sheet having a negative image, a first cover sheet, a pair of spacers framing the image, a quantity of liquid photo polymer filling the area over the image and between the spacers, a substrate film over the photo polymer filling, a second cover sheet, and a second ridged UV clear panel. The sandwich is held together by clamps and is placed over a raised UV window in a UV window box to selectively harden the photo polymer. Following initial hardening, excess photo polymer is washed away, the hardened photo polymer is immersed in an exposure mixture and placed over the UV window for final hardening. The raised UV window allows easy assembly of the sandwich and clearance for the clamps.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to making rubber stamps and in particular to an improved method for making rubber stamps from a photo polymer. 
         [0002]    Rubber stamps are commonly used for business, personal, and hobby uses. Businesses and individuals commonly use return address stamps to simplify providing a return address on mail. Businesses often use stamps to date stamp incoming mail, or to stamp a preliminary draft of a letter or document accordingly. Stamps are also commonly used to place decorative images on cards, letters, or envelopes. 
         [0003]    While stamps have long been available, custom stamps have required special ordering, and are often limited in content to common text or images selected from a catalog. Such stamps were neither quickly available, or adaptable to an individual&#39;s interests. More recently, stamps have been made at home or in small offices using a photo polymer and a UV light apparatus, but unfortunately, known UV light apparatus results in awkward and sometimes difficult handling of materials. In particular, known UV lights are housed in boxes having a flat surface for assembling and for laying a clamped assembly against. The flat surface does not allow easy grasping and room for the clamps. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention addresses the above and other needs by providing a simple and inexpensive apparatus and method for producing stamps using a photo polymer. A sandwich is constructed over a raised UV window in a UV window box, which sandwich includes a first UV clear panel, a translucent sheet having a negative image, a first cover sheet, a pair of spacers on opposite sides of the image, a quantity of liquid photo polymer filling the area over the image and between the spacers, a substrate film over the photo polymer filling, a second cover sheet, and a second UV clear panel. The sandwich is held together by clamps and is placed over the raised UV window to selectively harden the photo polymer. Following initial hardening, excess photo polymer is washed away, the hardened photo polymer is immersed in an exposure mixture and placed over the UV window for final hardening. The raised UV window allows easy assembly of the sandwich and clearance for the clamps. 
         [0005]    In accordance with one aspect of the invention, there is provided a method for producing a stamp. The method includes assembling a sandwich using steps of creating a negative image on a translucent sheet, placing a first UV clear panel on a horizontal surface, placing the translucent sheet on the first clear panel with the negative image facing upright, placing a first cover sheet over the translucent sheet, placing spacers on the first cover sheet positioned on opposite sides of the negative image, pouring a photo polymer over the first cover sheet between the spacers, placing a substrate film over the photo polymer with a rough side of the substrate film against the photo polymer and a smooth side of the substrate film away from the photo polymer, placing a second cover sheet over the substrate film, placing a second UV clear panel over the second cover sheet, and clamping the two UV clear panels together to form the sandwich. A partially hardened photo polymer is created by the steps of flipping the sandwich, positioning the sandwich over a raised UV window of a UV window box, turning on a UV light under the UV window for a first period of time, flipping the sandwich, positioning the sandwich over the raised UV window, and turning on the UV light for a second period of time to complete partial hardening of the photo polymer. The stamp is prepared for final hardening by steps of removing the clamps from the UV clear panels, removing the UV clear panels, removing the second cover sheet, removing the substrate sheet, washing the photo polymer with a water and detergent mixture, brushing the photo polymer to remove non-hardened photo polymer material, rinsing the washed photo polymer material, repeating the washing and rinsing until a stamp image is clear, placing the partially hardened photo polymer face down in a container containing a water and exposure powder mixture, placing the container containing the hardened photo polymer over the raised UV window and turning on the UV light for a third period of time to complete hardening of the photo polymer. The completed stamp is provided by the steps of removing the fully hardened photo polymer from the container, drying the fully hardened photo polymer; and trimming the fully hardened photo polymer to produce the stamp. 
         [0006]    In accordance with another aspect of the invention, there is provided apparatus for producing a stamp. The apparatus includes a UV window box and a sandwich. The UV window box includes a housing, a raised UV window on a top surface of the housing above the UV light, at least one UV light residing in the housing under the raised UV window, a power source electrically connected to the UV light, and a timer controlling the connection of the power source to the UV light. The sandwich includes a first UV clear panel, a translucent sheet bearing a negative image, a first cover sheet residing over the translucent sheet, a pair of spacers residing on opposite sides of the negative image over the first cover sheet, a volume of a liquid photo polymer residing over the first cover sheet and between the spacers, a substrate film residing over the liquid photo polymer, a second cover sheet residing over the substrate film, a second UV clear panel residing over the second cover sheet, and clamps holding the UV clear panels together. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0007]    The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
           [0008]      FIG. 1  shows apparatus and materials according to the present invention for producing photo polymer stamp pads. 
           [0009]      FIG. 2  is a cross-sectional view of an Ultra Violet (UV) window box according to the present invention taken along line  2 - 2  of  FIG. 1 . 
           [0010]      FIG. 3A  describes a method according to the present invention for producing the photo polymer stamp pads. 
           [0011]      FIG. 3B  concludes the method according to the present invention for producing the photo polymer stamp pads. 
       
    
    
       [0012]    Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
         [0014]    Apparatus and materials according to the present invention for producing photo polymer stamp pads are shown in an exploded view in  FIG. 1  and a cross-sectional view of an Ultra Violet (UV) window box  10  according to the present invention taken along line  2 - 2  of  FIG. 1  and a sandwich  11  is shown in  FIG. 2 . The UV window box  10  includes a housing  10   a  containing at least one UV light  32 , and preferably containing two approximately 15 watt UV lights. A raised UV window  12  in the housing  10   a  is provided to allow UV light to escape. The raised UV window  12  has a length L between approximately four inches and approximately seven inches long and preferably approximately six inches, and a width W between approximately two inches and approximately four inches and preferably approximately three inches. The raised UV window  12  includes upward extending sides  36  which support the sandwich  11  having a height H between approximately ½ inches and approximately one inch above a top surface  38  of the housing  10   a,  and preferably approximately 0.7 inches above the top surface  38  of the housing  10   a.  This positioning above the top surface  38  advantageously provides space for the clamps  34  as well as facilitating the assembly, placement, and removal of the sandwich  11  from the raised window  36 , for example, provides space for a user&#39;s fingers between the sandwich  11  and the top surface  38 . The raised UV window  12  may include a clear glass cover or a cover made from any material which is transparent to UV light, or may be an opening with no cover. 
         [0015]    A timer  30  controls power provided to the UV light  32  by a cord  28  and plug  26 . A sandwich  11  is held together by clamps  34  and rests on the window  12  for timed exposure to UV light. Raising the window  12  allows space for the clamps  34  on the sandwich  11  to clear the top surface of the box  10  when the sandwich  11  is residing on the raised UV window  12 . The sandwich  11  has a top surface  11   a  and a bottom surface  11   b.    
         [0016]    During initial phases of producing a photo polymer stamp, materials are stacked to form the sandwich  11  preferably including, from bottom to top, a first clear panel  14   a,  a translucent sheet  16  having a negative image, a first cover sheet  18   a,  spacers  20 , a substrate film  24 , a second cover sheet  18   b,  and a second clear panel  14   b.  The clear panels  14   a,    14   b  should be sufficiently ridged to transfer the force from the clamps  34  to the photo polymer so that the thickness of the resulting stamp is controlled, for example, is the same thickness as the spacers  20 . The panels  14   a  and  14   b  are preferably glass panels, but may be any ridged panel which is transparent, or sufficiently transparent to UV light. The negative on the translucent sheet  16  blocks UV light to create the stamp. The image may be hand drawn or computer generated, or any image which blocks UV light. The specific translucent sheet material used is selected for the type of printer used, for example, an ink jet printer or a laser printer. The cover sheets  18   a  and  18   b  may be any smooth transparent film. 
         [0017]    The spacers  20  provides a volume for a liquid photo polymer  22  to be poured over the negative  16  and determine the thickness of the stamp produced from the photo polymer. An example of a suitable spacer is ¼ cm thick plastic. The spacers should be longer than the longest desired stamp, and are preferably approximately seven cm long, and approximately one cm wide. An example of a suitable liquid photo polymer  22  is  140  polymer made by Ideal in Piscataway, New Jersey. 
         [0018]    The cover sheets  18   a  and  18   b  prevent material from becoming stuck to the clear panels  14   a  and  14   b,  and are not a necessary element of the sandwich  11 . 
         [0019]      FIG. 3A  describes a method according to the present invention for producing the photo polymer stamp pads. The method includes transferring liquid photo polymer to a small bottle for easier handling and allowed to settle for a settling time of preferably at least about five hours to allow bubbles to escape from the liquid photo polymer at step  40 , create a stamp design on a computer at step  42 , print a negative of the design on a translucent sheet at step  44 , cutting away excess sheet material away around the negative design at step  46 , place a first clear panel over a horizontal surface, preferably on the raised UV window  12 , at step  48 , place the negative design, face up, on the first clear panel at step  50 , placing a first cover sheet over negative at step  52 , smoothing out the first cover sheet at step  54 , positioning spacers on opposite sides of negative design at step  56 , pouring liquid photo polymer over the negative design between the spacers at step  58 , placing a substrate film over the photo polymer, rough side down and smooth side up at step  60 , placing a second cover sheet over the substrate film at step  62 , placing a 2nd clear panel over the second cover film at step  64 , clamping the clear panels together in a biased closed manner to make a sandwich at step  66 , flipping the sandwich and position the sandwich over the raised UV window  12  with the negative image face down at step  68 , and turn on UV lights for a first period of time of preferably about  15  seconds at step  70 . 
         [0020]      FIG. 3B  concludes the method according to the present invention for producing the photo polymer stamp pads. The remaining steps include flipping the sandwich and positioning the sandwich back over the UV window with the negative image face up at step  72 , turning on the UV light for a second period of time of preferably about 60 seconds to complete partial hardening of the photo polymer at step  74 , removing the clips at step  76 , removing the clear panels at step  78 , removing the second cover sheet at step  80 , removing the substrate film and the negative at step  82 , washing the hardened photo polymer in a detergent water mixture at step  84 , brushing the hardened photo polymer to reveal an image at step  86 , remove the spacers at step  88 , rinsing the hardened photo polymer at step  90 , if the image is not clear, repeating washing and rinsing at step  92 , remove the first cover sheet at step  94 , placing the hardened photo polymer, negative face down, in a water and post exposure powder mixture at step  96 , placing the container, solution, and hardened photo polymer over the UV window, turning on the UV light for a third period of time of preferably about 60 seconds to compete hardening the photo polymer at step  100 , drying the hardened photo polymer at step  102 , and cutting away excess hardened photo polymer material at step  104 . 
         [0021]    The method of  FIG. 3A and 3B  may be altered to skip step  50  and to form the sandwich with the negative design placed face down over the second cover film after step  62 , and the resulting sandwich may be placed on the raised UV window without flipping. In either case, the sandwich is placed over the raised UV window with the negative image face down for the first hardening step and face up for the second hardening step 
         [0022]    While most users are likely to create a negative image on a translucent sheet using a computer, the negative image may also be created by drawing, a photographic process, a copying machine, or any other method allowing a UV light blocking negative image to be created on a UV translucent sheet. 
         [0023]    The spacers preferably remain attached to the hardened polymer while washing the hardened photo polymer to make holding easier during washing, and to somewhat protect the hardened photo polymer from tearing or warping, but the spacers may be removed before washing. 
         [0024]    An example of a suitable post exposure powder, in particular for use with I-Series photo polymer made by Ideal, is iPXC-A post exposure powder. Preferably, iPXC-B post exposure powder is added to the iPXC-A post exposure powder to reduce or eliminate tacking on the surface of the rubber. 
         [0025]      25 ] In all cases, terms describing clear, translucent, or any other characteristic referring to the ability of light to pass through a material, is herein assumed to refer to the ability of UV light to pass through a material. Further, while a method using a UV window box  10  (See  FIGS. 1 and 2 ) was described above, any UV light source may be used as long as the exposure of the liquid photo polymer  22  to the UV light is controlled. The times recited for exposure to UV light assume new materials. When old materials are used, for example, old exposure liquids, a longer UV exposure may be required. Further, the first exposure time and the second exposure time may be adjusted to adjust the depth of the solid image, and a longer first exposure time will result in a deeper image. 
         [0026]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.