Abstract:
An ink cartridge or inkpad for use in a hand stamp in which the cartridge is made up of two parts. There is a frame portion and a central removed portion or well. Ink is deposited into the well and absorbed by the foam stamping member and the frame portion. In a first embodiment the central removed portion is reinserted back into the cartridge to provide additional ink storage medium and to impart structural strength to the stamping member. A trim ring supports the stamping member and locks the stamping member and ink cartridge into the stamp mount. This minimizes the mess associates with inking inkpads and also minimizes ink loss due to evaporation and drying. It also reduces the inventory of ink cartridges required by a stamp manufacturer as the cartridges are stored dry and the desired color ink is only placed in the ink cartridge when the stamp is manufactured for the user.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
   This invention relates to hand stamps and more particularly to a hand stamp that is received by the user as a self-contained pre-inked hand stamp that does not require the use of a separate stamp inkpad. 
   Most conventional stamps require manufacturing a stamping member from rubber or other flexible material. The stamping member is mounted on a handle that is grasped by the user. The stamping member is placed into contact with ink, usually contained in an inkpad. The inked stamping member is then pressed against the surface onto which the stamp image is to be transferred. Repetition of the stamping process required that the stamping member be pressed against the inkpad each time an image is to be transferred. This is a disadvantage to the user as it requires extra time for each re-inking step and slows down the stamping process if many stampings are to be done. It also requires the use of a separate inkpad that must be periodically re-inked. 
   An improved stamp was developed. This used a stamping member made from a permeable foam material that allowed ink to pass through the stamping member. The ink was held within the stamp and allowed to gradually ooze onto the stamping member. This eliminated the need for a separate stamp inkpad. 
   This type of stamp pad is illustrated in U.S. Pat. No. 5,942,312 issued to Venkataraman et al. This patent discloses a pre-inked thermoplastic foam which has open cells in the area that is designed to transfer ink and closed or sealed cells in the area which is designed to be impermeable to ink. The inkpad is pre-inked before the image is formed on the thermoplastic material. Thus if there is a problem with the image, the entire pad including the ink, is wasted. Furthermore there may be difficulties in forming an image on a pre-inked pad as it may be messy or require special handling due to the ink in the pad. 
   Hand stamp users preferred the ease and convenience of the pre-inked stamps. A separate inkpad with its inherent mess was no longer required. The stamp manufacturers now had the problem of creating the image on the foam stamp surface and pre-inking the stamp so that it was ready for use by the user. An improvement to creating the image on the stamp foam surface is illustrated in U.S. Pat. No. 5,858,298 issued to Leo Humal. This patent discloses a method to make the image on the surface of a porous thermoplastic material by heat sealing portions of the surface to define the image. In order to use the thermoplastic stamp surface, it is necessary to provide an ink cartridge with a supply of ink against the porous thermoplastic stamp material. One approach to pre-inking the stamp was to use a pre-inked cartridge. The pre-inked cartridge was shipped to the stamp manufacturer in a sealed airtight bag. The stamp manufacturer would cut the bag, carefully remove the pre-inked cartridge, place it in contact with the porous thermoplastic stamp surface, and allow the ink from the cartridge to migrate through the porous stamp surface. This generally took up to one hour for the ink migration to occur so that the stamp could be used. Thus the process was time consuming. The process was also still messy in that the cartridge had to be carefully removed, usually using tweezers or gloves. 
   Yet another problem was the large inventory of pre-inked cartridges required to be carried by the stamp manufacturer. A different size cartridge is required for each stamp size. In addition, each color offered must be stocked for all of the stamp sizes. This resulted in a large number of pre-inked cartridges being held in inventory. 
   Applicant&#39;s invention addresses and solves the problems of the prior art devices. It also has several advantages over the prior devices. The invention comprises a new and improved ink cartridge that is received into the hand stamp. The ink cartridge and foam stamping member are mounted in the hand stamp by means of a trim ring. The foam stamping member is made of a porous foam material. There are ink impermeable portions and open portions on the foam stamping member that define an image. A non-inked (dry) ink cartridge having a center portion removed is provided. The ink cartridge is placed on the backside of the foam stamping member in the trim ring. The proper color ink is then poured into the removed center portion of the ink cartridge. The ink migrates into the foam stamping member and the ink cartridge. The center portion that was removed from the ink cartridge is reinserted. The trim ring is then inserted into the hand stamp which is ready for printing. In an alternate arrangement, the foam stamping member is provided with a second layer of ink absorbing foam material that rapidly absorbs ink when it is poured into the removed center portion of the ink cartridge. 
   OBJECTS AND ADVANTAGES 
   Thus it is an object of the present invention to provide an ink cartridge for a hand stamp with a recess area that allows the stamp manufacturer to pour the ink into a recess. This allows a predetermined quantity of ink to be dispensed into the ink cartridge. 
   Another object is to provide an ink cartridge that has a center removed portion that is removed for depositing the ink onto the ink cartridge and reinserted after the ink has been absorbed into the ink cartridge and foam stamping member. 
   An advantage of the ink cartridge is that it allows the stamp manufacturer to inventory fewer ink cartridges as a separate ink cartridge is no longer required for each color stamp. The reason is that the desired color ink is poured into the ink cartridge just prior to use. 
   Yet another object is to provide a foam stamping member having a porous layer attached to the foam stamping member to increase the rate of flow of ink into the stamp member and thereby decrease the time it takes to complete assembly of the finished hand stamp. A related advantage of this increased flow rate is it allows the use of a porous ink cartridge having its center portion removed. 
   These and other objects and advantages will be apparent from reviewing the following Description of the Drawings and Description of the Preferred Embodiment. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front elevation view of the assembled stamp separated from the bottom cover. 
       FIG. 2  is a front exploded view of the hand stamp with the inventive ink cartridge. 
       FIG. 3  is a front exploded view in cross section of the hand stamp with the inventive ink cartridge. 
       FIG. 4  is a front view of the assembled stamp partially in cross section to illustrate the orientation of parts and means for fastening the entire stamp together. 
       FIG. 5  is an end view of the stamp mount. 
       FIG. 6  is a top plan view of the moveable shield. 
       FIG. 7  is a top plan view of the stamp frame. 
       FIG. 8  is an end view of the stamping member. 
       FIG. 9  is a cross section view of the trim ring taken along line  9 — 9  of  FIG. 2 . 
       FIG. 10  is a top plan view of the ink cartridge with a center portion removed. 
       FIG. 11  is a top plan view of the removed center portion. 
       FIG. 12  is a perspective view of the trim ring retaining the foam stamping member and the ink cartridge with the removed portion exploded therefrom. 
       FIG. 13  is a top plan view of an alternative ink cartridge with a plurality of portions removed. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Turning to  FIG. 1  there is illustrated a hand stamp  10  having the inventive ink cartridge of the present invention. The stamp  10  is commonly referred to a self inking hand stamp as it does not require the use of a separate inkpad that is not a part of the hand stamp  10 . Although the disclosure describes one type of self inking hand stamp, other types of self inking hand stamps are also available, although all operate similarly. There is a handle cover  12  designed to be grasped by the user. The handle cover  12  is mounted over a stamp frame  14 . A pair of nubs or protrusions  16  on the stamp frame  14  engages receiving holes in a bottom cover  18  to snugly retain the stamp frame  14  in the cover  18  when it is to be stored. 
     FIGS. 2 and 3  clearly illustrate the various parts and assembly of the stamp. The stamp frame  14  has a handle at an upper portion  22  with a central passageway  24 . The handle cover  12  is adapted to be slipped over the handle  20  to cover the central passageway  24 . A portion of the upper portion  22  is cut out to form a shoulder  26 . The handle has a lower portion  28  that has a pair of retainer plates  30  along each of its longest sidewalls. The retainer plates  30  hold two arms of a double wishbone spring member  32 . The other two arms of the wishbone spring member extend downward toward a bottom opening  34  of the stamp frame  14 . 
   A moveable shield  36  is dimensioned to be received within the bottom opening  34  of the lower portion  28  of the stamp frame  14 . The moveable shield  36  has a shield opening  38  that is aligned with the central passageway  24  in the stamp frame  14 . The moveable shield  36  has upstanding walls  40  that have a height sufficient to protrude below the bottom opening  34  when the shield is assembled into the lower portion  28 . There is a ledge  42  (see  FIG. 6 ) extending around the circumference of the shield  36 . The ledge  36  contacts the lower ends of the spring member  32 . In its normal non printing position, the moveable shield  36  is in contact with the surface that is to be imprinted with an image. If a downward force is applied to the handle  20  the ledge  42  pushes upward against the spring member  32  causing the moveable shield  36  to move upward resulting in printing the image as will be more fully described later. 
   A stamp mount  44  has upper and lower portions  46  and  48  respectively. There is an opening  50  passing through the stamp mount  44 . The opening  50  is also in alignment with the central passageway  24  and shield opening  38 . At the top of the stamp mount  44  are a pair of flexible latches  52  with barbs or catches  53 . There is also a plurality of catch openings  54  where the upper and lower portions join together. To assemble the stamp mount  44  to the stamp frame  14 , the upper portion  46  of the stamp mount  44  is inserted through the shield opening  38  and then into the bottom opening  34 . The flexible latches  52  flex inwardly to allow the upper portion  46  of the stamp mount  44  to pass through the upper portion  22  of the stamp frame  14 . Once the barbs  53  pass over the shoulder  26 , the flexible latches  52  spring outwardly to lock the stamp mount  44  to the stamp frame  14 . The moveable shield  36  is also retained between stamp mount  44  and the stamp frame  14 . The moveable shield is allowed slight vertical movement against the spring member  32 . As can be seen all three pieces, the stamp mount  44 , the moveable shield  36  and the stamp frame  14  are all held together by means of integrally formed latches and receiving openings without the need for any external fasteners. Oftentimes, the hand stamp  10  is supplied with the frame  14 , shield  36  and stamp mount  44  assembled. 
   Opposite the opening  50  in the stamp mount  44  is an open bottom  56 . This is adapted to receive a trim ring  68  that retains an ink cartridge or inkpad  60  and a porous foam stamping member  62 . The ink cartridge or inkpad  60  is preferably made of a porous foam material that absorbs and retains a thick printing ink. 
   The ink cartridge or inkpad  60  is more fully illustrated in  FIGS. 10–12 . The ink cartridge or inkpad  60  has a frame portion  63   a  and a removed central portion  65  creating an opening or well  63   b  within the frame portion  63   a . The removed central portion  65  is carefully cut from the cartridge  60  so that its walls are smooth so that the central portion  65  can be reinserted into the well  63   b . The ink cartridge or inkpad  60  is preferably made of a porous foam material that will absorb and retain ink. 
   The porous foam stamping member  62  has a printing side  64  and a non-printing side  66 . The stamping member  62  is prepared for printing an image by placing the image to be reproduced onto a clear plastic film. The image is normally comprised of black and white areas. The clear plastic film with the image on it is applied to the printing side  64  and the stamping member  62  is placed in a sealed light box with the printing side  64  pressed against a clear glass or plastic member. A xenon light is placed in the light box opposite the printing side  64  and energized for a predetermined time. The rays from the light cause a chemical reaction on the foam stamping member wherever there were white image areas. This causes a color change and seals what were the white areas resulting in areas that are non-permeable to the ink. The rays do not penetrate the black image areas and thus no reaction occurs on the printing side  64  of the foam stamping member  62  directly behind the black image areas. These areas remain unsealed and thus ink permeable. There are other methods available to form the image on the foam stamping member. The important point is that there are ink permeable and ink impermeable areas to define the image. 
   In the preferred embodiment the foam stamping member  62  has a thin foam layer  61  attached to it as seen in  FIG. 2 . The foam layer  61  is porous and absorbent so that it readily absorbs ink. The foam layer  61  is preferably manufactured from the same material as the cartridge  60 . The foam layer  61  is necessary when the frame  63   a  is made of a non porous material. Otherwise the ink will puddle in the well  63   b  and not be absorbed quickly enough into the stamping member  62 . 
   Once the image is formed on the printing side  64 , the foam stamping member  62  is placed with the image and printing side  64  down, into the trim ring  68 . The trim ring  68  has a plurality of catches or clips  70  disposed about its upper edge. The bottom of the trim ring  68  is substantially open with the exception of a small shelf  72  around the bottom of the trim ring  68 . The stamping member  62  is dimensioned to be received snugly within the trim ring  68  with the printing side  64  extending slightly below the bottom of the shelf  72 . The frame portion  63   a  of the non-inked ink cartridge  60  is then placed on top of the foam layer  61  of the stamping member  62  as seen in  FIG. 12 . A quantity of ink sufficient to fill the well  63   b  of the selected color ink is poured into the well or central removed portion  63   b . The number of impressions that the stamp will make before re-inking is necessary is determined by the amount of ink poured into the well  63   b . Filling the well  63   b  to the top insures the maximum number of impressions. 
   In the preferred embodiment the ink saturates the cartridge  60 , the foam layer  61  on the foam stamping member  62  and then, over time, the ink will also saturate the stamping member  62 . The foam layer  61  assists in the flow of ink from the well  63   b  into the stamping member  62  by providing an additional porous ink storage layer above the stamping member  62 . If time was of no concern, the foam layer  61  can be eliminated and the ink in the well  63   b  will eventually soak into the stamping member  62  and the cartridge  60 . However, if no foam layer is used, the frame  63   a  will have to be made of a non porous material or the frame  63   a  will leak ink. If no foam layer  61  is used, it may take several hours for the ink to saturate the stamping member  62 , compared to about twenty minutes by using the foam layer  61 . 
   The size of the well  63   b  is determined by the amount of ink that is necessary to saturate the stamping member  62  and ink cartridge  60 . The dimensions of the well  63   b  are calculated to equal the volume of ink. Thus, when the ink is poured into the well  63   b , it is poured to the desired level in the well  63   b  and allowed to saturate the ink cartridge  60  and stamping member  62 . 
   Once a portion of the ink has been absorbed by the layer  61  and the frame portion  63   a , the removed portion  65  from the ink cartridge is then reinserted into the well  63   b . This serves two functions. First, the removed portion  65  assists in absorbing the ink so that more ink can be stored extending the life of the hand stamp before re-inking. Second, the removed portion  65 , when reinserted, adds structural strength to the ink cartridge  60  which supports the stamping member  62 . This provides strength to the backside of the stamping member  62  when making impressions so that clear and uniform images are transferred. 
   In the alternative embodiment illustrated in  FIG. 13 , the ink cartridge  60  has a plurality of removed portions or openings  74 . These are illustrated as circular cut-out portions in this alternate embodiment, although other various configurations such as squares, rectangles or other geometric shapes will also work. Between adjacent removed portions are structural ribs  76 . These ribs  76  provide structural strength to the ink cartridge  60  during stamping so that the portions cut from the cartridge  60  to create the removed portions  74  are not re-inserted prior to using the cartridge  60 . The combination of ribs  76  made of the cartridge material and the removed portions  74  store approximately the same amount of ink as the preferred embodiment wherein the removed portion  65  is re-inserted into the well  63   b . This is due to the fact that the cartridge material absorbs about seven times its weight in ink. Furthermore the structural ribs  76  quickly absorb ink while the remaining ink in the removed portions  74  is absorbed into the foam layer  61 . This keeps from flowing into the outer edges of the cartridge and overflowing into the edges of the stamping member  62 . 
   The trim ring  68 , with the stamping member  62  and ink cartridge  60  positioned within it, is placed as a unit into the open bottom  56  of the stamp mount  44 . The several catches  70  are received in locking relationship in the catch openings  54  in the stamp mount  44 . This locks the trim ring  68  into the stamp mount  44 . The ink cartridge  60  is in intimate contact with the layer  61  on the stamping member  62 . The ink does not flow through the non-permeable areas but flows through the ink permeable areas to print the image. Once a stamping member  62  is saturated with ink, it is always ready for immediate use as long as there is ink in the stamping member  62 . When the ink is used up or dries out, the stamping member  62  can be re-inked. The handle cover  12  is removed, and ink can be injected through the opening  50 , through the central passageway  24  and into the ink cartridge  60 . Alternatively, the ink cartridge  60  can be removed and refilled or replaced. 
   In an alternative embodiment the ink cartridge  60  is actually made of two different materials. The frame portion  63   a  is made of a non porous material such as cork or plastic. When the well  63   b  is filled with ink, the frame  63   a  retains the ink within the well  63   b  until it saturates the stamping member  62  and the layer  61  (if present). Then the removed portion  65  is inserted into the well  63   b . The removed portion  65  can be made from an absorbent material such as layer  61  or can be made from a non absorbent material such as cork or plastic. This embodiment will not function as well as the preferred embodiment as it will not absorb ink as quickly nor will it store nearly as much ink as the preferred embodiment. Furthermore, a foam layer  61  is necessary as the frame  63   a  is non porous and will keep the ink within the well  63   b.    
   When the user wants to use the stamp  10  to print an image onto an image receiving surface, the user grasps the stamp  10  by the handle cover  12 . The stamp is removed from the bottom cover  18 . This exposes the stamping member  62 . However the moveable shield  36  protrudes below the bottom of the stamp mount  44  which retains the stamping member  62  above the image receiving surface. The user pushes down on the handle cover  12 , which in turn forces the stamp frame  14  downward. The moveable shield  36  contacts the image receiving surface which pushes against the moveable shield  36 . The moveable shield  36  overcomes the force of the spring member  32  and moves upward into the stamp frame  14 . The printing surface  64  contacts the image receiving surface and ink transfers from the ink permeable areas on the stamping member  62  to the image receiving surface. 
   Thus there has been provided a hand stamp with an improved ink cartridge that fully satisfies the objects and advantages set forth herein. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.