US3911812A

US3911812A - Printing apparatus

Info

Publication number: US3911812A
Application number: US404007A
Authority: US
Inventors: William T Flynn; Erich L Wolf
Original assignee: Reliance Electric Co
Current assignee: Mettler Toledo International Inc
Priority date: 1973-10-05
Filing date: 1973-10-05
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14
Also published as: CA998564A

Abstract

Disclosed is printing apparatus for printing one or more characters on a surface. A plurality of print heads, each having dies for the printing of the individual characters, are movable between a printing position and a rest position. The characters are formed by actuating preselected die character segments mounted in each of the print heads. A pivot assembly mounts the print heads and moves them between the rest and printing position. The pivot assembly includes a plurality of parallelogram pivot arms, each of which mounts a single print head. As the print heads move from the rest position to the printing position, ink is applied to the dies. As the print heads approach the printing position, the parallelogram pivot arms move the print heads in a horizontal plane and urge the heads against the surface.

Description

United States Patent 11 1 1 1 3,911,812

Flynn et al. 1 Oct. 14, 1975 [541 PRINTING APPARATUS 1918,002 1/1974 Knoth....- 101 41 [75] Inventors: William T. Flynn, Perrysburg, Ohio;

Erich L. Wolf, Riverside, Calif. Primary ExaminerEdgar Burr Assistant Examiner-Edward M. Coven [73] Ass1gnee: Reliance Electric Company, Pepper Pike, Ohio 22 Filed: 0a. 5, 1973 [57] ABSTRACT Disclosed is printing apparatus for printing one or [21] Appl' 404007 more characters on a surface. A plurality of print heads, each having dies for the printing of the individ- Cl 197/1 ual characters, are movable between a printing posi- 101/103 tion and a rest position. The characters are formed by [5 1] Int. Cl. 1341,] 7/70 actuating preselected die character segments mounted [58] Field of Search 101/35, 1, 41-44, in each of the print heads. A pivot assembly mounts 101/93 197/ R, 178/30 the print heads and moves them between the rest and printing position. The pivot assembly includes a plu- [56] References Cited rality of parallelogram pivot arms, each of which UNITED STATES PATENTS mounts a single print head. As the print heads move 3,080,813 3/1963 Staub et a1. 101 43 the rest Wsition to the Priming 1305160, ink is 1111693 12/1963 Williams applied to the dies. As the print heads approach the 3,168,863 2/1965 McRae printing position, the parallelogram pivot arms move 3,195,452 7/1965 Stevens the print heads in a horizontal plane and urge the 3,242,855 3/1966 Noll et a1. heads against the surface. 3,625,142 12/1971 Bresler 3,724,369 4/1973 Gery et a1. 101/41 X 9 Claims, 13 Drawing Figures US. Patent Oct. 14, 1975 Sheet 1 of4 3,911,812

fITj'Z- U.S. Patent 0a. 14, 1975 Sheet 2 of 4 3,911,812

US. Patent Oct. 14, 1975 Sheet 3 of4 3,911,812

US Patent 0a. 14, 1975 Sheet 4 of4 3,911,812

PRINTING APPARATUS BACKGROUND OF THE INVENTION This invention relates to printing apparatus and particularly apparatus for printing characters on surfaces, such as the sides of. shipping cartons. In the manufacture of various articles of commerce, it is often desirable to print on labels or on the surfaces of shipping cartons, for examples, identification numbers, weights, or similar characters. In prior art techniques, the shipping containers have often been marked by means of a printed or typed label supplied with an adhesive; by stenciling or hand applying the characters to the shipping container surfaces; or by the printing of the characters directly to the surfaces of the shipping containers. Direct printing apparatus has generally not been suitable for making large characters because of surface variations from container to container. For example, if the containers are moving along a conveyor, many prior art printing apparatus were not suitable because of the close control required in order to insure that the surface is at the correct position adjacent the printing apparatus.

Because of the deficiencies in prior art printing apparatus, it has been difficult to rapidly print large size characters directly on the container surfaces, such that the weight of the container is legible at normal distances.

SUMMARY OF THE INVENTION The present invention is particularly adapted to printing characters, for example, large format weight characters directly on surfaces such as the sides of shipping containers. The apparatus includes a plurality of printing heads which are mounted on a pivot assembly. The pivot assembly includes a plurality of parallelogram pivot arms, each of such parallelogram pivot arms mounting a single print head. Each of the print heads includes a plurality of die segments for the printing of individual characters, for example, weight numerals. The characters are formed by actuating preselected ones of the character segments. Various combinations of seven different segments may be used for forming the digits through 9. The alternative of 16 segments may be arranged for selectively printing the digits, the alphabet, and several other characters. The die segments are mounted to move in the print head between a retracted and an actuated position. A pressurized fluid is supplied to cylinders mounted within the print heads to selectively move the preselected clie segments to their actuated positions. At this time, a main cylinder, which is operatively connected to the pivot assembly, begins to move the print heads from their rest positions toward their printing positions. The die segments engage an inking assembly, which includes a plurality of inking rollers, thereby inking the individual die segments. A cam means insures that only the faces of the actuated die segments are inked and that the ink assembly is moved outwardly of the printheads after the die segments are inked.

In a preferred embodiment, which is subsequently described, the printing apparatus forms a portion of a system in which cartons holding articles are weighed and the weight is subsequently printed on a surface of cartons. A conventional scale having a digital output is used for generating weight signals. The weight signals control and preselect the individual die segments.

The primary object of the present invention is to provide an improved printing apparatus for printing characters on a surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of printing apparatus constructed in accordance with the present invention, with a fragmentary. showing of a carton in a printing position;

FIG. 2 is an elevational view of the printing apparatus shown in FIG. 1;

FIG. 3 is an enlarged, fragmentary elevational view, similar to FIG. 2, and showing the inking operation;

FIG. 4 is a view similar to FIG. 3, showing the printing apparatus. in its printing position;

FIG. 5 is an enlarged, fragmentary elevational view, taken along the line 55 of FIG. 4;

FIG. 6 is an enlarged, fragmentary plan view, showing one of the print rollers, taken along the line 66 of FIG. 4;

FIG. 7 is an enlarged, fragmentary elevational view, taken along the line 77 of FIG. 6; 4

FIG. 8 is an enlarged elevational view with parts broken away, showing a print head in printing position;

FIG. 9 is an enlarged elevational view, taken along the lines 9-9 of FIG. 8;

FIG. 10 is a top view of the print head shown in FIG.

FIG. 11 is a rear view, taken along the line 11-1 1 of FIG. 8;

FIG. 12 is a vertical, sectional view, taken along the line l212 of FIG. 9; and

FIG. 13 is a diagrammatic view showing the numeral characteristics which may be formed from the seven segment print head shown in FIGS. 8-12.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, printing apparatus according to the present invention is generally indicated by the reference numeral 20. The printing apparatus 20 will be described in a system in which cartons containing articles are weighed and the weight is printed on a surface of the carton. A carton 21 having a surface 22 is shown in FIGS. 1 and 2. The printing apparatus 20 includes base members 23, top members 24, a back plate assembly 25, and a front plate assembly 26.

A pair of pillow blocks 27 mount a shaft 28. A lever 29 is fixed adjacent one end of the shaft 28. An air cylinder 30 has a rod 31, which is pivotally connected by a clevis 32 to the free end of the lever 29. A plurality of print head assemblies 34 are mounted on the shaft 28. In the present embodiment, there are four print head assemblies 34-37. Referring to FIG. 3, the print head assembly 37, which is representative of all of the print head assemblies 34-37, includes a pivot block 38 which is pinned to the shaft 28. A top block 39' is spaced from the pivot block 38 by a pair of flexure strips 40 and 41. The pivot block 38, top block 39 and flexure strips 40 and 41 form a parallelogram. This assembly is an important feature of the present invention.

Print heads 42-45 are mounted on the top block 39 of the print head assemblies 34-37, respectively. Referring to FIGS. 8-12, the print head 42 is shown. This print head is representative of all of the print heads 42-45. The print head 42 includes a body 47 which mounts a plurality of air cylinders 48. Each of the air cylinders 48 has a rod 49 which is attached to an individual die segment 50. In the present embodiment, seven die segments 50 are provided in the entire die assembly 51. In a manner well known in the prior art, the seven segment arrangement allows the printing of all of the digits, as shown in FIG. 13. When preselected ones of the rod 49 are extended, the respective die segments 50 are moved from their rest position to their printing positions. Referring to FIGS. 11 and 12, inlet hoses 52, which supply air to the respective air cylinders 48, are operatively connected to the air cylinder 48. A retraction inlet hose 53 communicates with an interior passageway 54 to supply air to the opposite side of the pistons of the air cylinders 48 to retract the die segments 50 from their printing position to'their rest position after the printing operation has been completed. Compressed air is supplied to the retraction inlet hoses 53 through a solenoid operated valve and manifold assembly 55 (FIGS. 1 and 2).

Referring to FIGS. 1 and 2, a bracket assembly 57 mounts a manifold assembly 58 which supplies compressed air to the inlet hoses 52 of the respective print heads 42-45. The manifold assembly 58 includes a plurality of solenoid operated valves 59. In the present embodiment, twenty-eight of the solenoid operated valves 59 are provided. The valves 59 are distributed in four banks of seven each, which are designated 59A, 59B, 59C, and 59D in FIG. 1. The seven valves 59 in the bank 59A are operatively connected through seven inlet hoses 52 to the individual air cylinders 48 in the print head 42. A decoder/driver (not shown) is energized for applying power to predetermined ones of the seven solenoid valve windings of the solenoid valves in, for example, bank 59A. The decoder/driver has a second input connected to the output of a character source, such as a binary coded decimal (BCD) output from an electronic scale. The decoder/driver may be a conventional BCD-to-seven segment decoder/driver which, for example, is commercially available in an integrated circuit. Depending upon the signal applied to the decoder/driver from the electronic scale, preselected ones of the solenoid valve windings are energized to open respective ones of the solenoid valves 59 in the bank 59A. The valves 59 control the delivery of the compressed air or other pressurized fluid to the hoses 52 and the air cylinders 48 and the print head 42. The respective die segments 50 are moved from their rest position to their printing position, as shown in FIG. 12. When the printing step is completed, the energized windings of the solenoid operated valves 59 are discharged and compressed air is furnished through the retract manifold 55, the retraction inlet hoses 53 and the passages 54, thereby moving the die segments 50 from the printing position to the rest position. While the above description has been described with respect to the print head 42, the remainder of the print heads 43-45 operate in a similar fashion. If desired, an additional cylinder arrangement is provided on one or more of the print heads, for example, the print head 45, in order to reproduce a decimal point, in addition to the seven die segments 50. In this particular embodiment, the decimal point is mounted adjacent the print head 45 and is operated by the compressed air system which supplies air to the main drive air cylinder 30. A solenoid operated valve assembly 61 is operatively connected to

air lines

62 and 63 to the main drive air cylinder 30 (see FIG. 1). After the individual solenoid operated valves 59 have been actuated, the drive cylinder solenoid valve assembly 61 is energized and fluid passes through the air lines 63 moving the rod 31 to the left or extended position, as shown in FIG. 1. When this occurs, the shaft 28 is rotated in a counterclockwise direction and the print heads 42-45 begin to rotate in an arcuate path toward the front plate assembly 26 of the printing apparatus 20. The individual preselected die segments 50 have already moved from their rest positions to their printing positions.

An inking assembly, generally indicated by the reference number 65, is pivotally mounted to the top members 24 of the printing apparatus 20. A shaft 66 extends between the top members 24 of the printing apparatus 20 and mount a pair of inking assembly side plates 67 (see FIG. 6). The side plates 67 include overlying flanges 68 which are positioned adjacent the top members 24 and are fastened to the top member 24 by a pair of retaining screws 69. When the retaining screws 69 are released, the entire inking assembly 65 may be rotated outwardly, as indicated in FIG. 2. The pivoting of the entire inking assembly 65 is useful for any type of maintenance work which might be necessary, for example, the changing of one of the ink rollers.

Referring to FIGS. 5-7, a pivot shaft 70 and a stop dowel 71 extend between the side plates 67 of the inking assembly 65. The stop dowel 71 is mounted for eccentric movement with an opening 72.

The pivot shaft 70 mounts U-shaped brackets 74-77. The U-shaped brackets 7477 are mounted on the shaft 70 by spacer sleeves 78 and tension springs 79 (see FIG. 7). The tension springs 79 bias the U-shaped brackets 74-77 in a counterclockwise direction as viewed in FIG. 7. Set screws 80 are provided so that the tension springs 79 may be adjusted, thereby adjusting the resulting forces on the brackets 74-77. This adjusts the rolling forces between ink rollers 83 and the extended die segments 50, thereby adjusting the amount of ink which is applied from the ink rollers 83. This, in turn, controls the contrast of the resultant print on the surface 22.

Each of the brackets 74-77 has a roller shaft 82 spaced from the pivot shaft 70 which mounts an individual inking roller 83. The rollers 83 may be, for example, disposable plastic ink-impregnated rollers.

Each of the brackets 74-77 includes a cam portion 84. Referring to FIG. 5, the print heads 42-45 each has a generally T-shaped configuration in vertical profile. Camming surfaces are defined at the upper side edges of the print heads 42-45 and are engaged by the cam portions 84 of the brackets 74-77 of the inking assembly 65 as the print heads move toward printing position. Referring to FIG. 7, after the preselected ones of the die segments 50 have been actuated and moved from their rest to their printing position, the main drive cylinder 30 is actuated and the print heads 42-45 begin to move in a counterclockwise direction. The extended die segments 50 engage the surfaces of the inking rollers 83, which are being biased downwardly. As inking is completed, the cam portions 84 of the brackets 74-77 engage the camming surfaces 85 of the print heads 42-45. The cam portions 84 and the camming surfaces 85 are so designed that when the inking of the extended die segments 50 is completed, the entire U- shaped brackets 74-77 are pivoted upwardly to the dashed line position indicated in FIG. 7 by the reference number 74A. The inking rollers 83 are maintained in an elevated position during the printing step as shown in FIG. 4. i I

With reference to FIG. 4, as the print heads 42-45 approach the surface 22, the print head assemblies 34-37 initially reach their vertical solid line position. As the shaft 29 continues to rotate, the print head assemblies 34-37 continue to the position indicated in FIG. 4 bythe dashed lines 37A. As mentioned above, the pivot block 38, top block 3 9 and flexure strips or

side members

40 and 41 form a parallelogram. Therefore, before the print heads 42-45 reach the top vertical solid line position as shown in FIG. 4, the extended die segments 50 make contact with the printing surface 22 before the main air cylinder 30 reaches its fully extended stroke. The additional extension of the main cylinder 30, after die segment contact, causes deflection of one of both of the flexure strips 40 and 41. This controls the force which the extended die segments 50 exert upon the printing surface 22 and at the same time enables the individual print heads 42-45 to align its extended die segments 50 to match the contours of the surface 22. It has been found that the parallelogram arrangement is an important feature of the present invention because it places the ink die segments 50 in a correct matching alignment with the surface 22 of the carton 21 during the printing step. In addition, the ability of the print head assembly 37 to flex and maintain the print heads 42-45 in a horizontal plane is important because it allows the print heads a greater degree of horizontal latitude than was true in most prior art devices. This is important because if the printing is being done on the sides of cartons, the surfaces might be slightly concave, convex, or a combination of both conditions. Therefore, the cartons might be slightly spaced from the printing apparatus 20. In most prior art apparatus, these conditions would result in poorly defined printed characters. In addition, the air pressure which extends the die segment cylinders 48 is kept relatively low. This provides a cushioning effect. If the container surface 22 is slightly concave, the cushioning effect insures that the central character will fully strike and print a full character on the surface 22.

After the printing step has been completed, a limit switch 87 is engaged (see FIG. 4). The limit switch 87 switches the valving solenoid in the valve assembly 61 which controls the main drive air cylinder 30 and also switches the valving of the manifold assembly 58. The die segments 50 move from their printing position to their rest or retracted position, before the print head assemblies 34-37 begin to move rearwardly from their printing positions to their rest positions. Retraction of the die segments 50 occurs when air is supplied through the retract manifold 55 to the retract inlet hoses 53. Air enters the passageways 54 and operates the pistons of the die segment air cylinders 48. As the print heads 42-45 move rearwardly, the cam portions 84 of the brackets 74-77 keep the inking rollers 83 from contacting the retracted die segments 50. After the rod 31 of the main drive air cylinder 30 is retracted, a limit switch 88 is engaged and returning apparatus stays in its rest position until the next article has been weighed and the apparatus is again actuated.

It has been found that printing apparatus, according to the present invention, can print up to thirty prints a minute with relatively large weight characters.

What we claim is:

1. Printing apparatus for printing characters on a surface comprising, in combination, at least one pivotally mounted print head assembly mounted on a pivot shaft, said print head assembly having a print head mounted thereon, said print head including a plurality of die segments defining a printing surface and movable between a rest position and a printing position, means for moving preselected ones of said die segments between the rest position and the printing position, inking means for applying ink to said preselected ones of said die segments and means for moving said print head in an arcuate path into printing relationship with such surface, said print head assembly defining a parallelogram comprising a pivot block mounted on said pivot shaft, a top block spaced from said pivot block, and a pair of spaced flexure members extending, in an opposed relationship, between said pivot block and said top block, said print head supported adjacent said top block, whereby said opposed flexure members of said parallelogram deflect upon rotation of the pivot shaft and move the die segments into engagement with a printing surface, said inking means including at least one ink roller mounted adjacent said print head and cam means for moving said ink roller away from said print head after inking is completed.

2. Printing apparatus according to claim 1, wherein said means for moving said print head includes a lever extending radially outwardly from said pivot shaft and a fluid cylinder operatively connected adjacent the distal end of said lever.

3. Printing apparatus, according to claim 1, wherein said inking means includes a horizontal shaft mounted above said print head, a U-shaped bracket mounted on said shaft, said ink roller being pivotally mounted on said bracket and spring means for urging said roller into engaging relationship with said print head.

4. Printing apparatus, according to claim 1, wherein said means for moving selected ones of said die segments comprise a plurality of cylinders mounted in said print head, each of said cylinders being operatively connected to one of said die segments, said cylinders moving said die segments from the rest position to the printing position and means for returning said die segments from the printing position to the rest position.

5. Printing apparatus, according to claim 4, including an air manifold assembly comprising a solenoid operated valve and an air conduit connected to each of said cylinders.

6. Printing apparatus for printing characters on a surface comprising, in combination, a plurality of print head assemblies, each of said print head assemblies including a pivot member, a pair of opposed flexure members extending outwardly from said pivot member, a print head mounted adjacent the outer ends of said flexure members, said pivot member, said flexure members and said print head defining a parallelogram, each of said print heads including a plurality of die segments defining a printing surface and movable between a rest position and a printing position, means for moving preselected ones of said die segments between the rest position and the printing position, inking means for applying ink to said preselected ones of said die segments, said inking means including at least one ink roller and cam means for moving said ink roller away from said print head after inking is completed and means for moving said print heads into printing contact with such surface whereby said moving means rotates said pivot being mounted on said pivot shaft.

8. Printing apparatus, according to claim 6, wherein said cam means includes a cam surface defined by at least one of said print heads and a cam member complementary with such cam surface and operatively connected to said ink roller.

9 Printing apparatus, according to claim 8, including means for urging said ink roller into engaging relationship with said print heads.

Claims

6. Printing apparatus for printing characters on a surface comprising, in combination, a plurality of print head assemblies, each of said print head assemblies including a pivot member, a pair of opposed flexure members extending outwardly from said pivot member, a print head mounted adjacent the outer ends of said flexure members, said pivot member, said flexure members and said print head defining a parallelogram, each of said print heads including a plurality of die segments defining a printing surface and movable between a rest position and a printing position, means for moving preselected ones of said die segments between the rest position and the printing position, inking means for applying ink to said preselected ones of said die segments, said inking means including at least one ink roller and cam means for moving said ink roller away from said print head after inking is completed and means for moving said print heads into printing contact with such surface whereby said moving means rotates said pivot member through an arc, the rotation of said pivot member through said arc serving to begin the movement of said print head in a direction perpendicular to such surface and the flexure of said flexure members serving to carry such preselected ones of said die segments into contact with such surface.

7. Printing apparatus, according to claim 6, wherein said means for moving said print heads includes a horizontal pivot shaft and a fluid cylinder operatively connected to said pivot shaft, said print head assemblies being mounted on said pivot shaft.

9. Printing apparatus, according to claim 8, including means for urging said ink roller into engaging relationship with said print heads.