WO2013175492A2

WO2013175492A2 - Pad printing machine

Info

Publication number: WO2013175492A2
Application number: PCT/IN2013/000227
Authority: WO
Inventors: Suresh TAKLE
Original assignee: Takle Suresh
Priority date: 2012-04-04
Filing date: 2013-04-04
Publication date: 2013-11-28
Also published as: WO2013175492A3

Abstract

A pad printing machine is disclosed. The pad printing machine includes at least one roller, a belt, at least a pair of pulleys and a printing pad. The at least one roller has at least one image etched on a surface thereof. The etched surface is provided with ink supply. Length of the belt is in multiples of cross-sectional perimeter of an article. The printing pad is disposed on a length of the belt that coincides with a print cycle. The reproduction of the etched image/s on the article is carried out by: rotary motion between the printing pad and the at least one roller thereby transferring the etched image/s from the at least one roller to the printing pad in the form of an inked image/s; and rotary motion between the printing pad and the article thereby transferring the inked image/s from the printing pad to the article.

Description

PAD PRINTING MACHINE

FIELD OF THE DISCLOSURE

The present disclosure relates to systems and methods used for printing. Particularly, the present disclosure relates to a pad printing machine.

BACKGROUND

Printing is a process of reproducing text and images, generally with ink. Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. Pad printing process includes a rotary pad printing process. A rotary pad printing process is used for printing a variety of cylindrical and conical articles such as bottles, buckets, barrels, pen barrels, cosmetic containers arid the like.

Generally, a rotary pad printing process includes an article to be printed, an etched image roller and a silicon pad. An etched image roller and a silicon pad are cylindrical in shape. Image to be printed on an article is etched on a cylindrical face of an etched image roller. Ink is deposited in the etched surface of ah etched image roller and thereon transferred to a silicon pad through rotary movement of the etched image roller and the silicon pad. An etched image roller and a silicon pad rotate in opposite directions. Ink transferred on a silicon pad is subsequently deposited on an article. The deposition occurs through rotary movement of a silicon pad and an article in opposite directions (concept similar to transfer of ink from an etched image roller to a silicon pad). Although, prior art rotary pad printing processes are useful for printing a variety of cylindrical and conical articles; the prior art rotary pad printing processes have certain drawbacks. For example, the size of a silicon pad is dependent on parameters including number of colors, diameter of article to be printed, print area, idle time between printing and non-printing cycles and the like. Further, a single cylindrical silicon pad is suitable only for a set of above-mentioned parameters. Consequently, the size and/or shape of a silicon pad is required to be modified if any one of the above parameters is changed.

Besides, once a silicon pad is cast of a particular size and shape, it cannot be modified without deteriorating its ink transfer capabilities. Therefore, in prior art rotary pad printing methods a new silicon pad is required to be casted, if any of the above-mentioned parameters is changed. Accordingly, the prior art rotary pad printing methods are inflexible in this respect.

Also, a silicon pad is expensive. Therefore, cost of a silicon pad and a new mould to cast the silicon pad is of important consideration each time a new silicon pad is to be cast. Yet another drawback of the prior art rotary pad printing methods is that, as diameter of article to be printed, number of colors and/or print area increases, the dimensions of a silicon pad is required to be increased in order to accommodate increased parameters. Consequently, the cost of a silicon pad and a mould increases, thereby rendering the method redundant for certain articles, number of colors and/or print areas. Also, proper handling of a large silicon pad is difficult in a factory environment. In addition, the foot print of a rotary pad printing machine for such increased parameters is so large that the machine occupies extensive area of a work shop floor.

Accordingly, there is a need of a pad printing machine that is cost effective. Also, there is a need of a pad printing machine that accommodates a range of diameters of cylindrical articles to be printed. Further, there is a need of a pad printing machine that transfers multiple inks/images on to an article to be printed in a single pass.

OBJECTS

Some of the objects of the present disclosure which at least one embodiment herein satisfies are as follows:

It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.

One object of the present disclosure is to provide a pad printing machine that is cost effective.

Another object of the present disclosure is to provide a pad printing machine that accommodates a range of diameters of cylindrical articles to be printed.

Still another object of the present disclosure is to provide a pad printing machine that transfers multiple inks/images on to an article to be printed in a single pass. Yet another object of the present disclosure is to provide a pad printing machine that minimizes operational cost of printing.

One more object of the present disclosure is to provide a pad printing machine that facilitates both single color printing and multi color printing.

Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.

SUMMARY

In accordance with one aspect of the present disclosure, a pad printing machine is disclosed. The pad printing machine includes at least one roller, a belt, at least a pair of pulleys and a printing pad. The at least one roller has at least one image etched on a surface thereof. The etched surface is provided with ink supply. The belt is adapted to facilitate reproduction of the etched image/s on at least one article. The length of the belt is in multiples of cross- sectional perimeter of the article. The at least a pair of pulleys is adapted to hold the belt in tension. The at least a pair of pulleys includes a primary driving pulley and a secondary driven pulley. The primary driving pulley has a diameter bigger than the secondary driven pulley. The printing pad is disposed on a length of the belt that coincides with a print cycle. The printing pad is adapted to reproduce the etched image/s on the article, wherein the reproduction of the etched image/s on the article is carried out by: rotary motion between the printing pad and the at least one roller thereby transferring said etched image/s from said at least one roller to the printing pad in the form of an inked image/s; and rotary motion between the printing pad and the article thereby transferring the inked image/s from the printing pad to the article.

In one embodiment of the present disclosure, the pad printing machine further includes a drive shaft, a primary gear, a printing roller gear and an article gear. The drive shaft is adapted to facilitate mounting of the primary driving pulley thereon. The primary gear is mounted on the drive shaft. The printing roller gear adapted to be engaged with the primary gear. The printing roller gear is functionally coupled to the at least one roller. The printing roller gear adapted to rotate the at least one roller in a direction opposite to that of the primary driving pulley. The article gear is adapted to be engaged with the primary gear. The article gear is functionally coupled to a fixture. The fixture is adapted to hold the article. The article gear is adapted to rotate the article in a direction opposite to that of the primary driving pulley.

Typically, the pad printing machine further includes an ink supplying mechanism adapted to supply ink to the etched surface. The ink supplying mechanism includes an ink tray, a blade and an ink outlet means. The ink tray is used for supplying ink to the etched surface. The blade is used for wiping out excess ink from the at least one roller. The ink outlet means is for removing the excess ink.

Additionally, a pulley adjustment mechanism is adapted to facilitate longitudinal movement of the secondary driven pulley. Typically, the at least one roller is adapted to configure longitudinal movement perpendicular to the belt for facilitating the at least one roller to be in contact with a length of the printing pad for a specified duration.

The number of multiples of the belt may be dependent on number of print cycles and number of idle cycles.

In one embodiment, the belt is a timing belt.

Further, the at least a pair of pulleys is timing pulleys.

Typically, the printing pad is disposed on the belt by means of casting.

In one embodiment, the printing pad is disposed on the length of the belt continuously.

Alternatively, in another embodiment, the printing pad is disposed on the length of the belt intermittently.

Furthermore, the printing pad is of silicon.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The disclosure will now be explained in relation to the non-limiting accompanying drawings, in which: FIGURE 1 illustrates a perspective view of a pad printing machine in accordance with one embodiment-;

FIGURE 2 illustrates a front view of the pad printing machine of FIGURE 1;

FIGURE 3 illustrates a tqp view of the pad printing machine of FIGURE 1; and

FIGURE 4 illustrates an enlarged view of an image transfer unit of the pad printing machine FIGURE 1.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The disclosure will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. The description hereinafter, of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The present invention provides a pad printing machine for facilitating transfer of 2-D images onto a 3-D object. 3-D objects include a variety of cylindrical and conical articles such as bottles, buckets, barrels, pen barrels, cosmetic containers and the like. Printing operation performed by a pad printing machine of the present disclosure is cost effective. Further, a pad printing machine of the present disclosure does not require significant changes in it for accommodating changes in number of colors, diameter of article to be printed, print area, idle time between printing and non-printing cycles and the like. Furthermore, a pad printing machine of the present disclosure requires comparatively low foot print area and thereby requiring less space for its installation.

Referring to Figures 1 to 4, a pad printing machine 100 is disclosed, in accordance with one embodiment. The pad printing machine 100 includes a plurality of rollers 102, a belt 104, a primary driving pulley 106, a secondary driven pulley 108, a printing pad 110, an article 112, a pulley adjustment mechanism 114, a drive shaft 116 (illustrated in Figure 2), a primary gear 118 (illustrated in Figure 2) for the priihary driving pulley 106, an article gear 120 (illustrated in Figure 2) for the article 112 and a printing roller gear 122 (illustrated in Figure 2) for the plurality of rollers 102.

The drive shaft 116 is rotated by a geared, motor. The primary driving pulley 106 and the primary gear 118 are mounted on the drive shaft 116. In one embodiment, the primary driving pulley 106 is a timing pulley. The primary gear 118 engages with the printing roller gear 122 to rotate the plurality of rollers 102. The plurality of rollers 102 is mounted on the same shaft as the printing roller gear 122. The plurality of rollers 102 rotates in a direction opposite to that of the primary driving pulley 106.

The primary gear 118 and the printing roller gear 122 have same module. Pitch circle diameter (PCD) of the primary gear 118 is selected such that a range of diameters of cylindrical articles to be printed can be accommodated. PCD of the printing roller gear 122 is same as the diameter of the article 112 to be printed. Also, engaging with the primary gear 118 is the article gear 120. PCD of the article gear 120 is same as the diameter of the article 112. An article holding fixture (not shown) is mounted on the same shaft as the article gear 120. The article gear 120 is continuously engaged with the primary gear 118. Therefore, once held on the fixture, the article 112 rotates continuously. The article 112 rotates in a direction opposite to that of the primary driving pulley 106. The article 112 is a 3-D object including but not limited to a variety of cylindrical and conical articles such as bottles, buckets, barrels, pen barrels, cosmetic containers and the like.

The belt 104 is mounted on the primary driving pulley 106 and the secondary driven pulley 108. The belt 104 is held in tension by the primary driving pulley 106 and the secondary driven pulley 108. In another embodiment, the belt 104 is held in tension by more than two pulleys. In one embodiment, the belt 104 is a timing belt. The printing pad 110 is disposed on the belt 104. In one embodiment, the printing pad 110 is disposed on the belt 104 by means of casting. However, the present disclosure is not limited to any particular method or device used for disposing the printing pad 1 10 on the belt 104. In one embodiment, the printing pad 110 is of silicon. The printing pad 110 is attached to the length of the belt 104 which coincides with the print cycle only, and not attached to a length of the belt 104 which coincides with idle cycle of the machine. In other words, the printing pad 110 is attached to the region of the belt 104 which is used to transfer ink from the printing roller 102 to the article 112 only. Selectively attaching the printing pad 110 to the belt 104 reduces cost of equipment. The printing pad 110 may, therefore, be attached continuously or intermittently to the belt 104.

The diameter of the primary driving pulley 106 is greater than that of the secondary driven pulley 108. The difference in diameters creates point contact of the printing pad 110 with the plurality of rollers 102 and/or the article 112. The secondary driven pulley 108 is an idle rotating pulley. The secondary driven pulley 108 is provided with the pulley adjustment mechanism 114 such that the belt 104 can be tensioned by adjusting the location of the secondary driven pulley 108. In one embodiment, the pulley adjustment mechanism 114 is adapted to provide longitudinal adjustment for adjusting the tension of the belt 104. Also, this longitudinal adjustment assists in accommodating belts of various lengths.

The height of the belt 104 and of the print pad 110 is such that it accommodates necessary print area. Length of the belt 104 is dependent on various parameters including number of colors, container change over time gap, diameter of article to be printed etc. Length of the belt 104 is calculated at the surface of printing. The length of the belt 104 is in multiples of cross- sectional perimeter of the article 112. In one embodiment, when the article 112 is cylindrical then the length of the belt 104 is in multiples of circumference of the article 112 to be printed. The number of multiples depends on number of print cycles and number of idle cycles.

Belt length calculation example:

If diameter of cylindrical article to be printed is 100mm, then circumference of the cylindrical article to be printed is 314mm. Therefore, belt length may be 628mm (2x), 942mm (3x) or 1256mm (4x) and the like.

Referring to Figure 4, an ink supplying mechanism 150 is disclosed. The ink supply mechanism 150 is adapted to supply ink to the surface of the at least one image etched on the surface of the roller 102. The ink supply mechanism 150 includes an ink tray 124, a blade 126, an ink outlet means 128 and ink 130. The ink tray 124 supplies the ink 130 to the etched surface. The blade 126 is adapted for wiping out excess ink from the roller 102. In one embodiment, the blade 126 is a doctor blade. However, the present invention is not limited to any particular type of blade described. The ink outlet means 128 removes excess ink from the roller 102 to outside.

In use, the article 112 is held in the fixture and is rotated continuously. The belt 104 is rotated between the primary driving pulley 106 and the secondary driven pulley 108. The printing pad 110 on the tensed belt 104 picks up ink/image(s) from the plurality of rollers 102 by means of rotary motion between the printing pad 110 and the plurality of rollers 102. More specifically, rotary motion between the printing pad 110 and the plurality of rollers 102 facilitates transferring of the etched image/s from the plurality of rollers 102 to the printing pad 110 in the form of an inked image/s. Subsequently, the inked image(s) is transferred from the printing pad 110 to the article 112, by means of rotary motion between the printing pad 110 and the article 112 and thereby transferring the inked image/s from the printing . pad 110 to the article 112. Then, the printed article 112 is removed from the fixture.

The plurality of rollers 102 facilitates multi-color printing on the article 112. In one embodiment, the plurality of rollers 102 is adapted to configure longitudinal movement perpendicular to the belt 104. The movement enables the plurality of rollers 102 to be in contact with a length of the printing pad 110 for a specified duration. The specified duration being time required to transfer ink from the plurality of rollers 102 to the printing pad 110. Therefore, multiple inks/images may be transferred on to the printing pad 110 through plurality of printing rollers. Subsequently, these multiple inks/images are transferred on to the article 112 in a single pass of the belt 104.

In one embodiment, the pad printing machine 100 of the present disclosure utilize rotary pad printing method. Although, the present embodiment of the present disclosure is described in conjunction with the plurality of rollers 102, the pad printing machine 100 of the present disclosure can also be effectively used in conjunction with a single roller. The single roller is adapted to facilitate single color printing on an article to be printed.

TECHNICAL ADVANCEMENTS AND ECONOMICAL SIGNIFICANCE

The technical advancements offered by the present disclosure which add to the economic significance of the disclosure include the realization of:

• a pad printing machine that is cost effective;

• a pad printing machine that accommodates a range of diameters of cylindrical articles to be printed;

• a pad printing machine that transfers multiple inks/images on to an article to be printed in a single pass;

• a pad printing machine that minimizes operational cost of printing; and

• a pad printing machine that facilitates both single color printing and multi color printing; Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment to achieve one or more of the desired objects or results.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

Claims

A pad printing machine comprising: at least one roller having at least one image etched on a surface thereof, said surface provided with ink supply;

a belt adapted to facilitate reproduction of said etched image/s on at least one article, wherein length of said belt is in multiples of cross-sectional perimeter of said article;

at least a pair of pulleys adapted to hold said belt in tension, said at least a pair of pulleys comprising a primary driving pulley and a secondary driven pulley, wherein said primary driving pulley has a diameter bigger than said secondary driven pulley; and

a printing pad disposed on a length of said belt that coincides with a print cycle, said printing pad adapted to reproduce said etched image/s on said article, wherein said reproduction of said etched image/s on said article is carried out by:

o rotary motion between said printing pad and said at least one roller thereby transferring said etched image/s from said least one roller to said printing pad in the form of an inked image/s; and

o rotary motion between said printing pad and said article thereby transferring said inked image/s from said printing pad to said article.

The pad printing machine as claimed in claim 1 , further comprising:

• a drive shaft adapted to facilitate mounting of said primary driving pulley thereon;

• a primary gear mounted on said drive shaft;

• a printing roller gear adapted to be engaged with said primary gear, said printing roller gear functionally coupled to said at least one roller, said printing roller gear adapted to rotate said at least one roller in a direction opposite to that of said primary driving pulley; and

• an article gear adapted to be engaged with said primary gear, said article gear is functionally coupled to a fixture, said fixture adapted to hold said article, wherein said article gear is adapted to rotate said article in a direction opposite to that of said primary driving pulley.

The pad printing machine as claimed in claim 1, further comprising an ink supplying mechanism adapted to supply said ink to said etched surface, said ink supplying mechanism comprising:

• an ink tray for supplying ink to said etched surface;

• a blade for wiping out excess ink from said at least one roller; and

• an ink outlet means for removing said excess ink.

4. The pad printing machine as claimed in claim 1, further comprising a pulley adjustment mechanism adapted to facilitate longitudinal movement of said secondary driven pulley.

5. The pad printing machine as claimed in claim 1, wherein said at least one roller is adapted to configure longitudinal movement perpendicular to said belt for facilitating said at least one roller to be in contact with a length of said printing pad for a specified duration.

6. The pad printing machine as claimed in claim 1, wherein number of multiples of said belt is dependent on number of print cycles and number of idle cycles.

7. The pad printing machine as claimed in claim 1, wherein said belt is, a timing belt.

8. The pad printing machine as claimed in claim 1, wherein said at least a pair of pulleys is timing pulleys.

9. The pad printing machine as claimed in claim 1, wherein said printing pad is disposed on said belt by means of casting_*

10. The pad printing machine as claimed in claim 1, wherein said printing pad is disposed on said length of said belt continuously.

11. The pad printing machine as claimed in claim 1, wherein said printing pad is disposed on said length of said belt intermittently . The pad printing machine as claimed in claim 1, wherein said printing pad is of silicon.