Packaging machine with thermal imprinter and method

• US 5,371,521 A
• Filed: 04/01/1992
• Issued: 12/06/1994
• Est. Priority Date: 04/01/1992
• Status: Expired due to Fees

• Current Assignee: Automated Packaging Systems Incorporated (Sealed Air)
• Original Assignee: Automated Packaging Systems Incorporated (Sealed Air)
• Inventors: Wehrmann, Rick S.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): Tran, Huan
• Application Number:
  US07/861,597
• Time in Patent Office: 979 Days
• Field of Search: 346/134, 346/136, 346/76 PH, 53/459, 53/469, 53/477, 400/120, 400/611, 400/614, 101/228, 226/113
• US Class Current: 347/171
• CPC Class Codes: B65B 61/025 for applying, e.g. printing, code or date marks on material prior to packaging

Abstract

A thermal transfer printing apparatus for printing an elongate continuous web of items. The apparatus comprises a frame structure having an imprinter mounted thereon. A plurality of idlers supports the web of items and defines a path of travel for the web. A segment of the path of travel is adjacent the imprinter and its print head. A rockable arm is connected to the frame structure and contacts the web along a top surface of the web at two locations. A first of the locations is upstream of the print head and a second of the locations is downstream of the print head. The arm is connected to the frame structure about a pivot point and rocks about this pivot point during operation of the apparatus in a manner similar to a "teeter-totter." A stepper motor drives two drive rollers thereby advancing the web. When a selected item is in a proper printing position within the segment of the path of travel adjacent the imprinter, air cylinders actuate a nip and the print head against the drive rollers to maintain proper tension within the selected item. The rockable arm then rocks about its pivot point and the stepper motor drives the drive rollers to pull the selected item past the print head so that the item may be imprinted.

Claims

1. A thermal transfer printing apparatus for printing an elongate web comprising:

a. a frame structure;

b. an imprinter mounted on the frame structure including a print head;

c. the imprinter including a transfer material supply reel for supplying transfer material;

d. the imprinter also including a transfer material take-up reel for taking up transfer material after it is used;

e. a plurality of idlers carried by the structure for guiding such web and defining a path of travel for such web, a segment of the path of travel being adjacent the imprinter and the print head;

f. a rockable arm assembly connected to the frame structure, the arm assembly being adapted to contact the web along a surface of the web at two locations, a first of the locations being upstream of the print head along the path and a second location being downstream of the print head along the path, the arm assembly being rockable during operation of said apparatus to pull a portion of such web through said segment and past the print head;

g. a stepper motor connected to the frame structure;

h. drive rollers driven by the stepper motor for controlling advance of the web through said segment; and

,

i. a nip connected to the imprinter, the nip and print head being cooperable with the drive rollers to isolate such web portion in a proper printing position relative to the print head and the rockable arm assembly, the nip and print head further cooperating with the drive rollers as well as the rockable arm assembly to maintain proper tension within such web portion during operation of the apparatus.

2. The apparatus of claim 1 wherein the imprinter is pivotally mounted on the frame structure.

3. The apparatus of claim 1 wherein the supply reel and take-up reel each are isolated within the imprinter by protective ground plane shielding.

4. The apparatus of claim 1 wherein the imprinter further includes sensing means for sensing indicia on such web portion during rocking of said arm to control operation of the imprinter.

5. A thermal transfer printing apparatus for printing an elongated web comprising:

a. a frame structure;

b. an imprinter mounted on the frame structure including a print head;

c. a transfer material supply reel connected to the imprinter for supplying transfer material, the supply reel being isolated from the print head by a protective ground shield to protect the imprinter from static electricity;

d. a transfer material take-up reel connected to the imprinter for taking up such transfer material after it is used, the take-up reel being isolated from the print head by a protective ground shield to protect the imprinter from static electricity;

e. structure defining a path of travel for the web and for supporting the web during operation of the apparatus, a segment of the path of travel being adjacent the print head; and

,

f. structure for advancing the web along the path of travel.

6. The apparatus of claim 5 wherein the imprinter is pivotally mounted on the frame structure.

7. A thermal printing apparatus for printing an elongated web comprising:

a. a frame structure;

b. an imprinter including a print head, the imprinter being pivotally mounted on the frame structure thereby providing easy access to the imprinter for service and maintenance;

c. other structure carried by the frame structure defining a path of travel for the web and for supporting the web during operation of the apparatus, a segment of the path of travel being adjacent the imprinter and the print head; and

,

d. a releasable clamp means is operatively interconnectable between the imprinter and the frame structure for securing the imprinter in an operation position for printing work pieces, the clamp means being releasable to permit the imprinter to be pivoted to a service and maintenance position.

8. For use with a packaging machine including a housing and frame structure, the machine being of a type with which a web in a form of a chain of pre-opened bags is fed from a supply to a load station for loading the bags with products sequentially and one at a time to form packages, an improved imprinting system comprising:

a. components connected to the structure and delineating a path of web travel through the machine;

b. a teeter-totter movably connected to the structure, the teeter-totter being positioned along a section of the path and carrying certain of said components;

c. an imprinter positioned along said section of the path;

d. film feed arresting means for selectively preventing the feed of the web both to and from said section; and

e. power means operably connected to the teeter-totter for moving the teeter-totter and thereby causing said certain components to move a portion of such web disposed in said section relative to the imprinter as the arresting means prevents web feed to and from said section.

9. The system of claim 8 wherein at least one of said components is rotatable and connected to a rotation control means and said at least one of said components frictionally engages such web portion in said section to control the rate of movement of such web portion past the imprinter.

10. An improved packaging machine having web supply and bag loading stations connected to a housing and frame structure comprising:

a. a plurality of rolls connected to the housing and frame structure and establishing a path of web travel;

b. a web imprinter positioned along the path and including structure for selectively imprinting a section of a web as such web section is moved relative to the imprinter;

c. certain of said rolls establishing spaced accumulator loops of variable length portions of such web respectively positioned along the path upstream and downstream from the imprinter; and

d. motive means for shifting at least some of said certain rolls to move such web section relative to the imprinter as the imprinter is operated, such section movement being accomplished by reducing the length of such web portion in one of said loops by a given amount while concurrently increasing the length of such web portion in another of said loops by an amount equal to said given amount.

11. The machine of claim 10 wherein the motive means includes a pivotally mounted teeter-totter carried by the structure and said at least some of the certain rolls are carried by the teeter-totter.

12. The machine of claim 10 wherein a section feed rate control means is provided and comprises a pair of said rolls positioned on either side of said web and gripping the web therebetween and a rotation, rate control mechanism operably connected to at least one of the rolls of the pair.

13. An improved packaging machine comprising:

a. a housing and frame structure;

b. a web supply support carried by the structure;

c. bag positioning and opening mechanism carried by the structure and delineating a loading station;

d. elements operably connected to the structure and delineating a path of web travel from the support to the station;

e. an imprinter carried by the structure and positioned along a section of the path;

f. at least two of said elements being carried by the imprinter;

g. a pair of said elements being respectively arranged with said at least two elements in opposed sets, the elements of the opposed sets being positioned on opposite sides of the path;

h. opposed set clamping means operatively connected to the sets and adapted to selectively cause the sets to clamp a portion of a web in the path section between the elements of each set;

i. two other of the elements being a spaced pair of loop-establishing elements respectively positioned along the path upstream and downstream of the path section, the loop-establishing elements being positioned to establish upstream and downstream variable path length loop portions of the path;

j. loop size control means carried by the structure and operably connected to loop-establishing elements for increasing the path length of one of the loop portions a given amount while concurrently reducing the path length of the other of the loop portions an amount equal to the given amount; and

,

k. reverse web motion arresting means carried by the structure and positioned along the path at a location downstream from the loop-establishing elements and upstream from the station to clamp a web and prevent retractive web motion toward the loop portions as the loop size control means is operated to shift the loop-establishing elements.

14. The machine of claim 13 wherein at least a majority of the elements are rolls.

15. The machine of claim 13 wherein a path length adjustment mechanism is positioned along the path between said section and the station and is adapted to adjust the path length between the section and the station for adjusting the length of a web run between the section and the station whereby a bag to be loaded and a web portion to be imprinted may be concurrently registered respectively in the station and in the section.

16. The machine of claim 13 wherein the opposed set clamping means comprises a pair of air cylinders.

17. The machine of claim 13 wherein one of the elements of one of the sets is a print head.

18. The machine of claim 13 wherein the loop size control means includes a pivotally mounted teeter-totter which rotatably supports the loop-establishing elements and a power means selectively to effect pivotal movement of the teeter-totter.

19. The machine of claim 18 wherein the power means is an air cylinder.

20. The machine of claim 13 wherein at least one of the elements is a feed roll and wherein the arresting means is a drive mechanism connected to the feed roll for selectively causing and preventing feed roll rotation.

32. The imprinter of claim 20 wherein the housing includes transversely disposed end walls and wherein one of the end walls carries an imprinter control panel.

21. A packaging machine comprising:

a. a housing and frame structure having web supply and packaging stations;

b. motor driven feed rolls carried by the structure near the packaging station for pulling a web to feed it from the supply station along a path of travel to the packaging station;

c. a control carried by the structure,

the control being adapted to sense a desired positioning of a packaging portion of the web at the packaging station and to emit a motor control signal when a desired positioning has been achieved;

d. the control being connected to the feed roll motor drive to cause the motor to terminate web feed in response to a motor control signal;

e. an imprinter assembly carried by the structure and positioned along the path upstream from the feed rolls, the assembly including imprinter control electronics connected to the control;

f. the assembly including at least two stepper motor driven roll elements and at least two clamp elements, each of the roll elements being paired with a corresponding one of the clamp elements to provide a plurality of web section control sets, the elements of each set being disposed on opposite sides of the path;

g. clamp means operatively connected to each of the control sets selectively to effect relative movement of the elements of each set from a web clamped, section feed control position to a spaced position permitting free web feed therebetween when the feed rolls are operating;

h. the electronics including an enablement means connected to the control and responsive to motor control signals, the enablement means being adapted to enable imprinter assembly operation in response to such signals; and

,

i. the electronics being connected to the clamp means and adapted to actuate the clamp means to shift the elements of each set from their spaced to their feed control positions after enablement in response to receipt of a motor control signal.

22. The machine of claim 21 wherein one of the clamp elements is a print head.

23. The machine of claim 21 wherein the control includes a spark gap detector.

24. The machine of claim 21 wherein a path length adjustment mechanism is positioned along the path between the assembly and the station and is adapted to adjust the path length between the section and the packaging station for adjusting the length of a web run between the assembly and the packaging station whereby a bag to be loaded and a web portion to be imprinted may be concurrently registered respectively in the packaging station and adjacent the assembly.

25. The machine of claim 21 wherein the opposed set clamp means comprises a pair of air cylinders.

26. The machine of claim 21 wherein the machine comprises multiple imprinter assemblies mounted in a juxtaposed relationship.

27. The machine of claim 21 wherein loop delineating elements are carried by the structure and positioned along the path to delineate a pair of accumulator loops, one of which is upstream of and the other of which is downstream of the assembly.

28. The machine of claim 27 wherein a loop size control means is interposed between the loop delineating elements and the structure.

29. The machine of claim 28 wherein the loop size control means includes a pivotally mounted teeter-totter which rotatably supports the loop-establishing elements and a power means selectively to effect pivotal movement of the teeter-totter.

30. An imprinter for use with a packaging machine or the like comprising:

a. a housing of generally rectangular solid configuration having a transverse dimension and a lengthwise dimension substantially greater than its transverse dimension;

b. the housing having generally flat side walls each adapted to be juxtaposed against a like imprinter whereby a plurality of such imprinters may be operated in coordinated fashion on a workpiece;

c. the housing a base adapted to be positioned adjacent a workpiece path of travel when the imprinter is in use;

d. a print head mounted in the housing near the base and having a transverse dimension only slightly smaller than the transverse dimension of the housing;

e. foil supply and take-up reel supports mounted in the housing at supply and take-up locations and spaced further from the base than the print head when the imprinter is in use, the supports being adapted to receive spools of foil at spaced locations, such foil being of a width substantially equal to the transverse dimension of the print head;

f. a reel drive mounted within the housing at a location offset from the supports;

g. narrow drive transmission means having portions interposed between each reel location and respective slightly spaced side wall portions, the drive transmission means being operatively interconnected to the drive and the support for take-up of foil;

h. electronics mounted in the housing further from the base than the drive and the supports;

i. the supports, the print head and other structure defining a foil path of travel from the supply location to the take-up location and including a path section along the base; and

,

j. static electric shielding interposed between the path and the electronics.

31. The imprinter of claim 30 wherein the housing has a vertical dimension when the base is horizontal which is substantially greater than both the housing lengthwise and transverse dimensions.