Patent Application
20090007809
The present invention relates to making rubber stamps and in particular to an improved method for making rubber stamps from a photo polymer.
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.
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'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.
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.
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.
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.
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:
Corresponding reference characters indicate corresponding components throughout the several views of the drawings.
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.
Apparatus and materials according to the present invention for producing photo polymer stamp pads are shown in an exploded view in
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 11a and a bottom surface 11b.
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 14a, a translucent sheet 16 having a negative image, a first cover sheet 18a, spacers 20, a substrate film 24, a second cover sheet 18b, and a second clear panel 14b. The clear panels 14a, 14b 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 14a and 14b 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 18a and 18b may be any smooth transparent film.
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.
The cover sheets 18a and 18b prevent material from becoming stuck to the clear panels 14a and 14b, and are not a necessary element of the sandwich 11.
The method of
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.
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.
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.
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
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.
