Apparatus and method for printing onto a polymeric web

Abstract

The present invention is directed to a method and apparatus for securely applying print to a web of continuous polymeric film. The web can first travel in a machine direction on a tensioning roller and onto a folding board whereupon the web is divided into first and second partial widths with a cross-section of the web taking on a U-shape or a V-shape. In between the cross-section of these two partial widths a printer can be placed such that the printer prints onto an inner surface of first partial width. Once the printing is complete, the folding of the web can be completed such that an inner surface of the second partial width is in contact with, covers, and protects the printed matter placed onto the first partial width.

Claims

1. A method for securely applying print to a web of continuous polymeric film, the method comprising: the web travelling in a machine direction, the web comprising first and second edges at opposite ends of the web in a cross direction, the cross direction perpendicular to the machine direction, a first tensioning roller in front of a folding board, the first tensioning roller transferring the web onto the folding board, the folding board folding the web, the folding forming a crease into the web in the machine direction prior to completion of the folding, the folding defining a first partial width of the web extending from the crease to the first edge of the web and a second partial width of the web extending from the crease to the second edge of the web, locating a print head between the first and second partial widths of the web, the print head placing printed matter onto an interior surface of the first partial width at a print location on the web, once the printed matter is placed on the first partial width, the folding board collapsing the folded web such that an interior surface of the second partial width is in at least in partial contact with the interior surface of the first partial width, and the second partial width contacting the print location on the first partial width due to completion of the folding.

2. The method of claim 1, further comprising: the folding board forming a cross-section with a V-shape into the web, the first and second partial widths of the web corresponding to first and second legs of the V-shape and the crease corresponding to an apex of the V-shape, and the print head located within the V-shape.

3. The method of claim 2 further compromising: the first and second partial widths equaling an entire width of the web in the cross direction.

4. The method of claim 2 further comprising: the web transferring from the folding board to a set of post folding rollers once the folding is complete.

5. The method of claim 1 further comprising: the web generally flat without any folds in the web prior to the web transferring to the folding board.

6. The method of claim 1 further comprising: a centerline of the web aligned with the crease in the web.

7. The method of claim 1 further comprising: a centerline of the web not aligned with the crease in the web resulting in the first and second edges of the web offset from each other in the cross direction once the folded web is collapsed.

8. The method of claim 1 further comprising: the web comprising more than a single layer.

9. The method of claim 8 further comprising: the web comprising four layers of film.

10. The method of claim 1 further comprising: the printed matter comprising thermal wax print.

11. An apparatus for securely applying print to a web of continuous polymeric film, the apparatus comprising: a first tensioning roller for maintaining tension on the web travelling in a machine direction, wherein the web comprises an upper surface and a lower surface, wherein the web further comprises first and second edges at opposite ends of the web in a cross direction, the cross direction perpendicular to the machine direction, a folding board located downstream of the machine direction from the first tensioning roller, wherein the web transitions from the first tensioning roller to the folding board and the folding board folds the web, wherein the folding forms a crease into the web and a first partial width is defined in the web that extends from the crease to the first edge of the web and a second partial width is defined in the web that extends from the crease to the second edge of the web, and a print head located between the first and second partial widths of the web, wherein the print head prints onto the first partial width at a print location on the web, wherein once the printing is complete, the folding board collapses the folded web such that the upper surfaces of the first and second partial widths are at least in partial contact with each other such that the upper surface of the second partial width contacts the print location.

12. The apparatus of claim 11 wherein: the folding board comprises a V-shaped folding board such that the folding board forms a V-shaped cross-section into the web and the first and second partial widths of the web correspond to first and second legs of the V-shape.

13. The apparatus of claim 12 wherein: the crease in the web corresponds to an apex of the V-shape folding board.

14. The apparatus of claim 13 wherein: the first and second partial widths equal an entire width of the web in the cross direction.

15. The apparatus of claim 14 wherein: a centerline of the web is aligned with the crease in the web.

16. The apparatus of claim 14 wherein: a centerline of the web is not aligned with the crease in the web such that the first and second edges of the web are offset from each other once the folded web is collapsed.

17. The apparatus of claim 11 wherein: the web comprises more than a single layer of film.

18. The apparatus of claim 17 wherein: the web comprises four layers of film.

19. The apparatus of claim 11 wherein: the web transfers from the folding board to a set of post folding rollers.

20. The apparatus of claim 11 wherein: the printed matter comprises thermal wax print.

Description

BRIEF DESCRIPTION OF THE RELATED DRAWINGS

(1) A full and complete understanding of the present invention may be obtained by reference to the detailed description of the present invention and certain embodiments when viewed with reference to the accompanying drawings. The drawings can be briefly described as follows.

(2) FIG. 1A provides a plan view of a continuous web 106 of polymeric film.

(3) FIG. 1B provides a cross-sectional view of the continuous web 106 of FIG. 1A, the polymeric film having nominal thickness.

(4) FIG. 2 provides a front perspective view of a web printing system 100.

(5) FIG. 3 provides a side perspective view of web printing system 100 of FIG. 2.

(6) FIG. 4A provides a cross-sectional view of web 106 and a printer 102 of web printing system 100 of FIG. 2 taken from cutting plane C-C. Folding board 108 is not shown in the figure for ease of illustration.

(7) FIG. 4B provides a cross-sectional view of web 106 of the web printing system 100 of FIG. 2 taken from cutting plane D-D.

DETAILED DESCRIPTION OF THE INVENTION

(8) The present disclosure illustrates several embodiments of the present invention. It is not intended to provide an illustration or encompass all embodiments contemplated by the present invention. In view of the disclosure of the present invention contained herein, a person having ordinary skill in the art will recognize that innumerable modifications and insubstantial changes may be incorporated or otherwise included within the present invention without diverging from the spirit of the invention. Therefore, it is understood that the present invention is not limited to those embodiments disclosed herein. The appended claims are intended to more fully and accurately encompass the invention to the fullest extent possible, but it is fully appreciated that certain limitations on the use of particular terms are not intended to conclusively limit the scope of protection.

(9) Referring initially to FIGS. 1 and 2, plan and cross-sectional views of a continuous web of polymeric film 106 is disclosed. Because web 106 is of nominal thickness, its thickness is shown merely by a single line in the drawings. In certain embodiments, web 106 can comprise a single layer and in further embodiments web 106 can comprise multiple layers of polymeric film. Web 106 can also comprise a collapsed tube of polymeric film formed via a blown film extrusion process. Although not shown, web 106 may also comprise a C-folded polymeric film formed from a slit collapsed tube of polymeric film as known in the art. In further embodiments, web 106 can comprise a web which has undergone a certain amount of steps of being converted into polymeric bags, such as side-sealed drawstring trash bags or wave-cut bottom sealed trash bags.

(10) In certain embodiments, web 106 can be formed from various classes of polyethylene polymers, such as low density polyethylene (LDPE), linear low density polyethylene (LLPDE), and high density polyethylene (HDPE). However, various other types of polymers may be used to form web 106, such as various types of nylon, PET, and polypropylene.

(11) As further shown in FIGS. 1A and 1B, continuous web 106 can have first and second edges 114 and 116 defined at opposite edges along a cross direction of web 106. Also shown by FIG. 1A, centerline A can extend along a machine direction of web 106. As mentioned above, in certain embodiments of the present invention, continuous web 106 can be C-folded. In addition, the C-folded web can have each side of the C-fold hemmed such that a partial width along each edge 114 and 116 of web 106 comprises four layers of film. As further shown by FIG. 1B, web 106 can also have an upper surface 107a and a lower surface 107b.

(12) Now turning to FIGS. 2 and 3, front and side perspective views of a first embodiment of the present invention, web printing system or apparatus 100, is disclosed. As shown in the figures, web printing system 100 can include a printer or print head 102 with a printer frame 104 holding printer 102 in place adjacent to a folding board 108. Web printing system 100 can further include a pre-printing tensioning roller 110 located in front of or upstream of folding board 108 and printer 102. Downstream from folding board 108 and on an opposite side of printer 102 from first tensioning roller 110 can be a set of post folding rollers 112.

(13) In certain embodiments of the present invention and as shown in FIGS. 2 and 3, folding board 108 can be a V-shaped folding board. As shown in the figures, V-shaped folding board 108 can have an apex 124 at the intersection of the two legs of the V-shape. Continuous web 106, traveling in the machine direction, in at least certain embodiments, can pass onto folding board 108 after moving from pre-printing tensioning roller 110.

(14) As continuous web 106 passes over folding board 108, a cross section of web 106 can be formed into a V-shape by board 108 so that first and second partial widths 106a and 106b of web 106 correspond to first and second legs of a V-shape, as shown by FIG. 4A. Additionally, a crease 118 can be formed in web 106 due to the web passing over apex 124 of board 108.

(15) As further shown by FIGS. 4A and 4B, first partial width 106a can extend from first edge 114 to crease 118. Additionally, second partial width 106b can extend from second edge 116 to crease 118 of web 106. Furthermore, as shown by FIG. 4A, first partial width 106a can have an interior surface 126 and second partial width 106b can have an interior surface 128 located within the V-shape. Web 106 can be folded such that upper surface 107a of web 106 corresponds to inner surfaces 126 and 128 and outer surface 107b corresponds to the outer side of the V-shape.

(16) In certain embodiments, the V-shaped cross section in web 106 can be formed such that apex 124 of the V-shape folding board 108 is centered between the first and second edges 114 and 116 of web 106 at centerline A as shown in FIG. 1A. In further embodiments, as shown in FIGS. 4A and 4B, web 106 can be placed off-center of apex 124 so that the V-shaped cross-section is offset from centerline A of web 106.

(17) As best shown by FIG. 4B, when centerline A of web 106 is placed off-center of apex 124, partial widths 106a and 106b of web 106 are offset from each other once folding of web 106 is complete. This off-centering of web 106 also results in first and second edges 114 and 116 of web 106 being separated from each other once the folding of web 106 is complete. In contrast to this result, if centerline A is aligned with apex 124 of folding board 108, first and second edges are aligned with and proximate to each other once the folding of web 106 is complete.

(18) Printer 102 can be located along the web at the point where V-shaped cross-section is formed in web 106, in between first and second partial widths 106a and 106b and adjacent to upper surface 107a, as depicted in FIGS. 2, 3 and 4A. In at least certain embodiments, printer 102 can be proximate to the interior surface 128 of second partial width 106b. Furthermore, at least in certain embodiments, printer can be an inkjet printer or a thermal wax printer. Printer 102 can be oriented such that printer's 102 ink stream is generally perpendicular to interior surface 128 of second partial width 106b. As web 106 passes printer 102, printed matter 122 can be placed onto interior surface 128 of web 106 from printer 102.

(19) Once printed matter 122 is applied to web 106, web 106 can fully transition off of folding board 108 and move towards post-folding rollers 112. FIG. 4B shows a cross section of web 106 taken from cutting plane D-D of FIG. 2 once folding board 108 has completely folded web 106. FIG. 4B illustrates a gap between partial widths 106a and 106b; however, this is merely for ease of illustration. It is contemplated for thin polymeric films as utilized with the invention, that the surfaces of partial widths 106a and 106b will be substantially in contact with each other.

(20) As mentioned above, FIG. 4B shows web 106 once folding of web 106 is complete. FIG. 4B further shows that interior surfaces 126 and 128 of partial widths 106a and 106b are brought towards each after folding other such that inner surfaces 126 and 128 are at least in partial contact with each other. Furthermore, with upper surface 107a spanning the width of web 106, partial width 106a of upper surface 107a is placed into at least partial contact with partial width 106b of upper surface 107a when web 106 is completely folded.

(21) As addressed above and illustrated by FIGS. 4A and 4B, web 106 can be placed on folding board 108 off-center such that fold 118 is not centered in the cross direction of web 106. As a result, partial widths 106a and 106b are unequal such that second edge 116 of web 106 extends past first edge 114 once folding is complete. Once folding of web 106 is completed, print matter location 122 on interior surface 128 of second partial width 106b can be covered by and in contact with the interior surface 126 of first partial width 106a.

(22) Partial width 106a covering printed matter 122 can be advantageous as web 106 undergoes further processing, especially when printer matter 122 comprises thermal wax print. Applicant has identified that when thermal wax printed matter 122 is not covered by the folded web 106, a certain amount of the printed matter 122 can detach from web 106 and onto downstream converting mechanisms, such as post-folding rollers 112. The buildup on such rollers can then detach from the rollers and mark over subsequent printed matter 122 on continuous web 106. Eventually, the buildup can interfere with the advancement of web 106 past post-folding rollers 112. The covering of printed matter 122 on second partial width 106b by first partial width 106a protects printed matter 122 and keeps printed matter 122 from being obscured and detaching from print location 122 and attaching onto processing equipment such as post-folding rollers 112.

(23) The specific embodiments depicted herein are not intended to limit the scope of the present invention. Indeed, it is contemplated that any number of different embodiments may be utilized without diverging from the spirit of the invention. Therefore, the appended claims are intended to more fully encompass the full scope of the present invention.