Title of Invention

"MULTIPLE COLOR ROUND PAD PRINTING APPASATUS"

Abstract The invention provides for printing multiple colors on curved surfaces. The object of the invention is to provide a fixture mechanism that enables accurate printing of multiple colors on curved surfaces with high repeatability. It economizes time and movement between the printing of multiple colors. It also prints multiple colors on the same machine without unloading. The invention also overcomes elongation of printing on curved surfaces towards the edges. Smudging of the ink by rubbing is also eliminated. The invention ensures correct loading of component to ensure repeatability of printing. The invention provides means for a synchronized motion between the horizontal push cylinders and the pads. The mechanical coupling and synchronized rotary and linear motion mechanisms ensure correct printing with a high accuracy and repeatability.
Full Text The invention relates to a multiple color round pad printing apparatus. More particularly the invention relates to an apparatus for printing multiple colors on curved surfaces.
Background of invention:
Pad printing of substrates with an image, in particular those with curved surfaces have been long known. In the present machines, the source of ink in pad printing system for the printing of an image is a reservoir member having the shape of a cup turned upside down. Such an ink cup is passed over a printing plate or member (cliche) having a top planar surface in which a pattern or image is etched onto, e.g. a line of print. As the cup passes over the pattern in the printing, the pattern is flooded with ink. At the same time a rim or lip of the ink cup acts as a doctor blade and wipes off any excess ink from the image pattern. The ink pattern is then transferred to a flexible silicone pad or transfer member placed in pressure contact with the image. The transfer pad is then removed from contact with the printing plate and placed in pressure contact with the surface to be printing e.g., the surface of a catheter in the case of line printing or the surface of a golf ball in the case of logo printing, and the image is thus transferred to that surface. Meanwhile, the image on the printing plate is again inked. The pad is removed from contact with the surface just printed and returns to its home position for placement in contact again with the inked image on the printing plate. Thus, the image is transferred or pad printed onto the second of the items to be printed. This cycle continues until all the items to be printed with the image have been printed.
In ordinary pad printing machines being used for printing on curved surfaces first the component to be printed is loaded on to a fixture and the pad with image to be printed being lowered so as to touch the surface of the object, thereafter the fixture is pushed outwards by a horizontal push rod cylinder. Due to the pressure applied by the silicon pad from above and horizontal motion of fixture, the component is forced to undergo a
circular- motion. This circular motion accomplishes the required printing on curved surface. However, as the circular motion is purely due to rubbing and considering the inaccuracies of mechanical components, the printing undergoes a slip towards the edges. The result being that, the edges of the image to be printed are elongated. As there is rubbing between the component and the silicon pad the ink also gets smudged at times. Further there is no certainty as to where exactly the circular motion will begin. Thereby the accuracy and repeatability of printing are compromised and the end image on the component lacks reliability.
In order to print more than one color on the same component, after the printing the first color the component was loaded on to another machine to print the second color and so on. Alternatively, an ink cup with the second color was loaded on the machine to print the second color. This takes a lot of time and does not provide accuracy in printing. Further in case of rotary printing repeatability and accuracy are essential. The printing must be such that the different colors don't run into each other.
Objects of the Invention:
In order to overcome the above limitations the invention provides for a system to be used in pad printing devices while printing multiple colors on curved surfaces.
The object of the invention is to provide a system that enables accurate printing of multiple colors on curved surfaces with high repeatability.
Another object of the invention is to economize time and movement between the printing of multiple colors.
Another object of the1 invention is to print multiple colors on the same machine without unloading.
Further object of the invention is to overcome elongation of printing on curved surfaces towards the edges.
It is yet another object of the invention to eliminate smudging of the ink by rubbing.
Another object of the invention is to ensure correct loading of component to ensure repeatability of printing.
To achieve the aforementioned objectives and to print high quality multiple color images on curved surfaces the invention provides means for a synchronized motion between the horizontal push cylinders and the pads. The mechanical coupling and synchronized rotary and linear motion mechanisms ensure correct printing with a high accuracy and repeatability.
Summary of Invention:
A multiple color round pad printing apparatus for printing on curved surfaces comprising
- a plurality of ink cups moving over their respective cliches,
- a plurality of pads to print multiple colors disposed above said ink cups,
- transmission means to move said ink cups and said pads for printing on curved surfaces,
a fixture to hold said curved surface to be printed,
- a first base plate to hold said fixture,
- a pneumatic cylinder connected to said first base plate,
- a second base plate below the first base plate connected to a second pneumatic
cylinder below the first pneumatic cylinder,
- a joining block connected to the first base plate and the second pneumatic
cylinder for supporting and moving said fixture to the required pad,
- an adjustable height mechanism to raise or lower the base plates, and

said ink cups moving over their respective cliche plates to ink images on them and said pads picking up images from their respective cliche plates and transferring them to the curved surface to be printed.
Brief description of Accompanying Figures.
Figure 1 shows mechanically synchronized motion for single color printing. Figure 2 shows the system for two color pad printing.
Figure 3 shows the steps involved in printing the two colors as per the instant invention
Figure 4 shows the two ink cups holding two colors along with their respective cliche plates.
Figure 5 shows the two pads mounted on the transmission means.
Figure 6 shows the front and side view of the machine as defined by the instant invention.
Detailed description of invention:
The invention will be described for two color printing on curved surfaces by way of an example. However the instant invention can also be applied to multiple colors.
Figure 1 shows rotary pad printing mechanism for single color printing. Figure shows a fixture (4) connected to a pneumatic cylinder (5) by a rod (6). The fixture (4) has a shaft on which component to be printed (8) is loaded. A pinion (3) in mesh with rack (2) is mounted on the fixture. When pneumatic cylinder (5) pushes the fixture (4) outward on
base plate (7), the pinion in mesh with the rack also rotates. Rotation of the pinion thereby rotates the shaft on which the component is loaded. The pad (1) with an imprint of the image to be printed is lowered onto the component while rotation to accomplish the printing on curved surface.
Figure 2 shows the system for two color printing on curved surfaces in accordance to the instant invention. In addition to the system of figure 1, an additional pneumatic cylinder (10) is placed below the first pneumatic cylinder (5). Cylinder (10) has a corresponding base plate (13). The upper base plate (7) rests on a joining block (9) that is connected to the pneumatic cylinder rod (11) of cylinder 2. Thus movement of rod (11) in one direction moves the upper base plate (7) and thereby the fixture (4) along with the component to be printed (8), positioning it under the second pad for the second color printing. Movement of the rod (11) in other direction positions the upper base plate (7) and therefore the component (8) under the first pad again. Also movement of upper pneumatic rod (6) in one direction rotates the component in one direction for printing the first color and movement of the rod in the other direction returns the component to its home position.
Figure 3 shows the steps involved in printing two colors on a component according to the present invention. Step 1, shows both rods completely extended. The fixture (4) along with the component to be printed (8) is below the first pad. In step 2, rod 1 of upper pneumatic cylinder moves outwards thereby causing the pinion to rotate which in turn rotates the component in contact with pad 1. Step 3, shows the completion of first color printing under pad 1. Rod 1 of upper cylinder is in the home position. Step 4, shows the movement of the second rod of lower pneumatic cylinder moving towards home position. This movement also moves the upper base plate towards the second pad. At the same time rod 1 of the upper cylinder extends outwards again thereby returning the component to its home position. Step 5, shows the upper base plate under pad 2 and ready for the start of printing. Step 6 shows the second color printing being carried out under pad 2. The upper rod moves towards home thereby rotating the pinion and therefore the component to be printed. Step 7 shows the completion of the second color printing with
both cylinder rods at their home position. After this stage both rods extend again simultaneously to take position shown in step 1. The next component can now be loaded and the procedure repeated.
In case of three color printing the steps 4 to 7 will be repeated with the lower pneumatic cylinder positioning the upper base plate and thereby the component to be printed under the third pad.
Figure 4 shows the two ink cups holding two different colors, along with their respective cliche plates. The ink cups are connected to a transmission means by a lever mechanism and a block. Both ink cups are connected to the same transmission means and therefore move simultaneously over the cliche plates. The transmission means can be any known transmission means such as a pneumatic cylinder.
Figure 5 shows the two pads connected to the same block. The block in turn is connected to the same transmission means as the ink cups. The ink cups and pads thus move simultaneously. The two pads are disposed above their respective cliche plates. They move simultaneously, picking up images from the cliche plates and then moving forward to transfer the image on to the component on which printing is to be done.
Figure 6 shows the front and side views of the pad-printing machine according to the instant invention. The front view shows the two pads disposed above the two cliche plates Also the adjustable table height mechanism (15) is shown below the base plate (13). The mechanism (15) allows the height of the base plate to be raised to accommodate different size components on which printing is to be done. The side view of the machine shows the ink cups and pads connected to the same transmission means. Thus movement of the transmission means in one direction moves the pads over the component to be printed and the ink cups over the end of the cliche plate that has the image to be printed. The pads then move downwards to transfer the image to the component. Depending on under which pad the fixture with the component is that color printing takes place. Movement of the transmission means in the other direction moves the pads over the inked
image and the cups to other end of the cliche plate. The pads then move down to pick up the image and the process is repeated till both the colors are printed.




I Claim:
1. A multiple color round pad printing apparatus for printing on curved surfaces comprising:
- a plurality of ink cups moving over their respective cliches,
- a plurality of pads to print multiple colors disposed above said ink cups,
- transmission means to move said ink cups and said pads for printing on curved surfaces,
- a fixture to hold said curved surface to be printed,
- a first base plate to hold said fixture,
- a pneumatic cylinder connected to said first base plate,
- a second base plate below the first base plate connected to a second pneumatic
cylinder below the first pneumatic cylinder, - a joining block connected to the first base plate and the second pneumatic cylinder for supporting and moving said fixture to the required pad, an adjustable height mechanism to raise or lower the base plates, and said ink cups moving over their respective cliche plates to ink images on them and said pads picking up images from their respective cliche plates and transferring them to the curved surface to be printed.
2. An apparatus for multiple color round pad printing on curved surfaces as claimed in claim 1 wherein said fixture has a rack and pinion arrangement.
3. An apparatus for multiple color round pad printing on curved surfaces as claimed in claim 1 wherein said second base plate is placed below said first base plate, said joining block separating the two base plates.
4. An apparatus for multiple color round pad printing on curved surfaces as claimed in claim 1 wherein said pads and ink cups are connected to the same transmission means.
5. An apparatus for multiple color round pad printing on curved surfaces substantially as and herein described with reference to the accompanying drawings.

Documents:

116-del-2003-abstract.pdf

116-del-2003-claims.pdf

116-del-2003-complete specification (granded).pdf

116-del-2003-correspondence-others.pdf

116-del-2003-correspondence-po.pdf

116-del-2003-description (complete).pdf

116-del-2003-description (provisional).pdf

116-del-2003-drawings.pdf

116-del-2003-form-1.pdf

116-del-2003-form-19.pdf

116-del-2003-form-2.pdf

116-del-2003-form-5.pdf

116-del-2003-pa.pdf


Patent Number 196888
Indian Patent Application Number 116/DEL/2003
PG Journal Number 40/2008
Publication Date 03-Oct-2008
Grant Date 23-Mar-2007
Date of Filing 14-Feb-2003
Name of Patentee RAHOUL RAI
Applicant Address PLOT NO 44/45, SECTOR 18, GURGAON, HARAYANA,INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 RAHOUL RAI PLOT NO 44/45, SECTOR 18, GURGAON, HARAYANA,INDIA.
PCT International Classification Number B40J 3/407
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA