US3299804A

US3299804A - Article handling and electrostatic imprinting apparatus and method

Info

Publication number: US3299804A
Application number: US366981A
Authority: US
Inventors: Marlin A Schueler
Original assignee: UNIMARK CORP
Current assignee: UNIMARK CORP
Priority date: 1964-05-13
Filing date: 1964-05-13
Publication date: 1967-01-24
Anticipated expiration: 1984-01-24

Description

Jan. 24,- 1967 M. A. SCHUELER 8 4 ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD v ts-Sh t 1 Filed May 13,1964 6 ghee ee -71 v 3 I I: \\(\1 Q Lg w m 7 I :2 w Lk \E M Q) [l g m 3 q 1 g E "B m j m q q \('\l L r I J 10 m Q INVENTOR.

Martin Aschueler' mvw v AT TOPNEYS Jan. 24, 1967 M. A. SCHUELER 3,299,804 ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD 6 Sheets-Sheet 2 Filed May 13, 1964 INVENTOK Marlin A. Schueler W Maw m A 7' TOR/VEVS Jan. 24, 1967 M. A. SCHUELER 3,299,804

ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD Filed May 13, 1964 6 sheets sheet 5 INVENTOR.

Marlin Aschueler A TTO/PNEYS Jan. 24, 1967 sc u R 3,299,804

ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD File y 1964 e Sheets-Sheet 4 r //////////7&

INVENTOR.

Marlin A. Schueler ATTORNEYS Jan. 24, 1967 M A. SCHUE'LER 3,299,804

ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD Filed May 15, 1964 6 Sheets- Sheet C M M 0( Q T 9 LA INVENTOR. Marl in A, Sc hueler ATTORNEYS Jan. 24, 1967 M. A. SCHUELER 3,299,804

ARTICLE HANDLING AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOD Filed May 13, 1964 6 s-Sheet 6 Q I Q L;

Q) I T 6 9 k INVENTOR.

Marlin A. bchueler BY yM/MQM ATTORNEYS United States Patent 3 299 804 ARTICLE HANDLIhlG AND ELECTROSTATIC IMPRINTING APPARATUS AND METHOI) Marlin A. Schueler, Danville, Calif., assignor to Unimark Corporation, a corporation of California Filed May 13, 1964, Ser. No. 366,981 11 Claims. (Cl. 101-35) This invention relates generally to article handling and printing apparatus, and insofar as the printing step in the apparatus is concerned, it relates to electrostatic printing in which the printing medium is electrostatically deposited on the surface to be printed from a point spaced from said surface. Such electrostatic deposit of material is disclosed in United States Letters Patent No. 3,081,698 of March 19, 1963, issued to Childress et al.

One of the objects of this invention is the provision of improved means for electrostatic printing that insures a more even distribution of the printing medium than heretofore.

Another object of the invention is the provision of improved apparatus for more accurately and more rapidly printing on articles of different thicknesses than heretofore.

A still further object of the invention is the provision of improved apparatus for more rapidly and accurately printing on articles having diiferent surface contours than heretofore.

An added object of the invention is the provision of apparatus that includes conveying means driven by a single source of power, such as a motor, for simultaneously carrying a plurality of rows of articles past a processing station where each of the articles in said rows are processed, such as by printing, by processing units movable with the articles in said rows, and which units are connected with said single source of power and may be selectively deactivated for processing the units in any of said rows for replacement, repairs or maintenance, without stopping the conveying means.

A still further object of the invention is the provision of electrostatic printing apparatus for carrying units to be printed upon past a printing station in orderly succession at uniform time intervals, and which apparatus includes an arrangement whereby the printing medium will not be dispensed where there may be a gap in the orderly succession.

An additional object of the invention is the provision of an improved system in which special carriers are provided for supporting and moving articles to be printed upon, such as apples, eggs, potatoes, avocados, etc., in uniformly spaced relation past a printing station and provision is made at said station for giving each of such articles an electrostatic charge and conducting a surfacedry printing medium in the desired pattern onto the outer surface of each article in an electrostatic field established between a screen spaced from each article, and which screen has a charge opposite to that of said article.

In explanation, a battery of two or more endless carriers for carrying rows of individual articles in uniformly spaced relation, may be provided. Endless rows of printing heads, each having a printing screen, are provided and a common source of power, such as a motor is connected with the carriers and printing heads for simultaneously driving them. The rows of carriers and heads are so arranged that the carriers will register with the pinting heads as the endless rows of carriers and heads are actuated, and at a point in their movement, so the heads and carriers will move together in the same direction at said point. The carriers themselves are each adapted to hold an individual body, such as an apple,

orange, potato, egg, avocado, etc., and means is provided so each head will gently engage each unit at said point in the movement of the carriers and heads, to space the screens on the heads substantially equidistant from the outer surface of each article at said point, and the screen and article are given opposite electrostatic charges at said point so that a printing medium on the screen will be conducted to the surface of the article in the electrostatic field that is established between the oppositely charged items.

In the present invention, any desired row of printing heads may be inactivated, and any one or more of the inactivated heads may be replaced, repaired, refilled or otherwise manipulated While the rest of the apparatus operates normally, including the carrier for the articles.

Provision is made in the present invention for automatically preventing the ejection or dispensing of the printing medium unless an article is in a position to receive it, and means is also provided to prevent injury to the article that is printed upon and to prevent contact between the article and printing screen.

Since with printing screens having over three hundred mesh openings per inch for passage therethrough of the surface-dry printing medium, the medium must be in fine particles that should not be freely discharged into the air, and by the same token, in order to produce uniform printing, it is necessary that the particles are caused to move through the mesh openings. Provision is made in the present apparatus to accomplish these results, and to effect imprinting at a rapid rate.

Other objects and advantages will be obvious from the description and drawings.

In the drawings, FIG. 1 is a side elevational view of a printing apparatus embodying the present invention.

FIG. 2 is an enlarged, side elevational view of a portion of the apparatus shown in FIG. 1.

FIG. 3 is an enlarged, cross-sectional view taken along line 33 of FIG. 1.

FIG. 4 is a side elevational view of the portion shown in FIG. 3.

FIG. 5 is a fragmentary cross-sectional view taken generally along line 5-5 of FIG. 2.

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 5.

FIG. 7 is an enlarged, part sectional, part elevational view of one of the printing heads, broken in length.

FIG. 8 is a cross-sectional view of the full length of a printing head, taken along line 8-8 of FIG. 7.

FIG. 9 is a top plan view of the porton shown in FIG. 7.

FIG. 10 is a top plan view of one of the article holders on the conveyor.

FIG. 11 is a view taken along line 1111 of FIG. 10.

FIG. 12 is a side-elevational view of the holder of FIG. 10.

FIG. 13 is a top plan view of a slightly different form of holder.

FIG. 14 is a cross-sectional view taken along line 1414 of FIG. 13.

Referring to FIG. 1, the numeral 1 generally designates a horizontally elongated stationary frame 1 having horizontally extending and horizontally spaced, parallel side frame members 2 positioned in side-by-side relation supported on legs 3. A pair of horizontal parallel end shafts 4,5 are rotatably supported on the frame at the opposite ends of frame members 2, the shaft 4 being at the feed end of the machine, and shaft 5 at the discharge end thereof. A pair of endless chains 6, (FIGS. 2, 3, 4) extend over conventional pairs of sprocket wheels on said shafts 4, 5.

Secured to chains 6 are supports 7 of non-conductive electrical insulation material, which supports, in turn, carry article-holding and positioning holders, designated 8.

These holders may be of any suitable shape, and in the present instance are of electrical conductive material having convergently downwardly extending side walls 9' and an open bottom except for a bottom strip 10. One of the sides of the holder may be open on its trailing side to enable greater variation in the lengths of the articles held in the cup while definitely locating the leading end of each article, and the convergently downwardly extending lateral sides will center the article relative to the path of travel thereof.

Thus, each holder is generally of relatively shallow funnel shape with the two lateral sides projecting horizontally at a right angle to the third side, This description applies to the upper run of the conveyor, since the articles to be printed on are carried by the holders that are on said upper run. The chains 6 and holders 8 make up the conveyor, which is generally designated 11.

Parallel tracks or rails 12 (FIG. 3) slidably support the upper runs of the chains 6, and a horizontally extending, yieldable electrical conductor 13 (FIGS. 2, 3) is supported by non-conductive supports 14 on one of the rails 12 in a position below the upper run of the conveyor for slidably engaging the lower surfaces of a bottom strip 10 on each holder at the printing station. Cond-uctor 13 is thus insulated from the frame of the machine and a source of direct current potential 16 is connected at one end to the screws in the printing heads, and the other end is connected with conductor 13, as will be explained later in more detail.

Referring to FIG. 5, one pair of opposed horizontally extending, vertically disposed stationary plates or frame members 17 is shown, and relatively closely alongside one of the plates of this pair is indicated one plate 17' of a second corresponding pair. FIG. 1 shows the near side of one of what may be a battery of two or more machines, or a single machine, each alike, but with shafts 4, 5 being common to the several conveyors 11, and being operatively connected with a single source of power.

The vertically disposed, spaced, opposed

frame unembers

17, 17 of each pair thereof (FIG. 5) are respectively secured to frame 2 by bolts 18 (FIG. 2) that extend through vertical slots 19 in said plates, to permit vertical adjustment of the

frame members

17, 17 relative to frame 2. As mentioned above, plates or

frame members

17, 17 are stationary when in adjusted positions.

The description hereinafter will be restricted to one pair of opposed frame member 17, except where there is reason to mention frame members 17', since each of the units incorporating a pair of such frame members is similar.

The frame members 17 rotatably support a horizontal shaft 20 (FIGS. 1, 2) that extends transversely thereof and which shaft may also rotatably extend through plates 17' of additional units.

Secured on shaft 20 between opposed frame members 17 is a pair of horizontally spaced, vertically disposed, opposed, horizontally elongated plates (FIGS. 1, 2). The shaft 20, being rotatable in bearings carried by frame members 17 will support plates 25 for rocking about the axis of shaft 20, and shaft 20 is positioned at a point intermediate the ends of plates 25 to facilitate rocking of the plates and the elements carried thereby.

Shaft 20 is supported by plates 17 adjacent to the forward ends thereof. The words forward, forwardly, rear, and rearwardly are used with reference to the direction of movement of the upper run of conveyor 11, which moves in a forward direction from right to left as seen in FIGS. 1, 2.

The rear end portions of plates 25 extend slantingly upwardly from shaft 20, while the forward end portions forwardly of shaft 20 extend substantially horizontally when the apparatus is in a printing position.

A horizontal shaft 27 (FIG. 2) extends between and is rotatably supported by plates 25 at their forward ends,

and two pairs of

corresponding sprocket wheels

28, 29 are respectively secured on

shafts

20, 27.

Sprocket chains 30 connect the sprocket wheels 28 with sprocket wheels 29, and the forward shaft 27 is journalled for rotation in conventional adjustable bearing blocks 31 to provide a take-up for chains 30. It should be noted that there is a separate shaft 27 for each opposed pair of plates 17, 17'..

A plurality of cylindrical units generally designated 32 have the printing heads thereon, and said units are carried by the pair of chains 30'at equally spaced points therealong, and said units project outwardly of the endless chains 30 in a'vertical plane parallel with and intermediate the vertical planes in which the chains are disposed. Thus, when the forward end portions of plates 25 are horizontal, the units 32 carried by the lower horizontally elongated runs of chains 30' will move parallel with and over the holders 8 that are carried by the upper run of conveyor 11, and the spacing between the units 32 is the same as the spacing between holders 8.

The units 32 on the lower runs of chains 30 move in the same direction as the upper run of conveyor 11, and at the same speed, and the heads and holders are in register with each other along said runs, which is accomplished as follows.

A horizontal shaft 34 (FIG. 1) parallel with shaft 20 is rotatably carried by plates 17 adjacent to the rear ends of plates 17, and a sprocket wheel 35 is secured thereto on one end of said shaft,

A sprocket chain 36 connects sprocket wheel 35 with a sprocket wheel 37 secured on a shaft 38 that, in turn, is rotatably supported at its ends in bearings carried by the side frame members 2. A second sprocket wheel 39 is secured on shaft 38 and the latter is connected by a chain 40 with a sprocket wheel 41, which, in turn, is secured on a shaft 42 driven by motor 43.

Shaft 38 has a bevel gear 47 (FIG. 1) secured thereon, the teeth of which mesh with the teeth of a bevel gear 48 that is secured on a shaft 49.

Shaft 49 is disposed intermediate side frame members 2 and is supported for rotation in bearings on suitable cross plates 50 (FIG. 3) that connect said side frame members 2.

The shaft 49 (FIG. 1) extends from bevel gear 48 to the end-shaft 5 that is at the discharge end of the frame of the machine. A bevel gear 51 on shaft 49 at the said discharge end of the machine meshes with a bevel gear 52 on shaft 5.

By the above arrangement, motor 43 will drive the conveyors 11 on one or a battery of units.

The rear ends of plates 25 that mount the sprockets and chains supporting the units 32, project upwardly (FIG. 2) and a spacer and connecting bar 53 that functions as a handle are adapted to be manually grasped by the hand of an operator to swing the rear end of the mounting means or plates 25 downwardly. The positions of the units 32 relative to the shaft 20 are such that the units will swing upwardly relative to conveyor 11 when said handle is moved downwardly.

Shaft 34 carries a dog-clutch member 54 (FIG. 5) that is splined on shaft 34 for reciprocable movement on the latter toward and away from the other clutch member or plate 55 that, in turn, is rotatably supported on shaft 34 for being driven by the clutch member 54 when the

members

54, 55 are connected as seen in FIG. 5, said

members

54, 55 have the conventional dogs that interengage automatically when member 54 is moved toward member 55, and which dogs move out of engagement with each other when member 54 is moved on shaft 34 away from clutch member 55.

A sprocket wheel 56 is rigid with clutch member 55, and this sprocket wheel is connected by a chain 57 with a sprocket wheel 58 (FIG. 1) secured on shaft 20.

By the above arrangement it will be seen that the units 32 will be actuated, for movement, together with the conveyor 11 when the

clutch members

54, 55 are in engagement, but immediately upon disengagement of the clutch members the units 32 will be stationary and inoperative, although the movement of the conveyors will continue.

A vertically extending bar 59 (FIGS. 5, 6) is adjacent to an axial extension 60 (FIG. 5) of clutch member 54 and has a clevis 61 at its lower end, the arms of which clevis extend to opposite sides of said extension 59 and are pivotally connected thereto (FIG. 6). Said bar 59, in turn, is pivotally supported on a pivot 63 that is rigid with a portion of frame 1 (FIGS. 5, 6). The bar 59 swings in a vertical plane extending transversely of the machine; hence, when the upper end of said bar, as seen in FIG. 5 is swung counterclockwise, the clevis 61 will move to the right, or counterclockwise, to disengage the dogs on member 54 from the clutch plate 55.

A roller 64 (FIG. 5) is supported on the upper end of the bar 59, which roller extends into a vertically extending slot 65 formed in a vertically disposed plate 66 that rigidly connects plates 25. The upper end portion 67 of slot 65 extends at an angle to the vertical portion. When the plates 25 are swung downwardly and roller 64 enters the angularly extending portion 67, the bar 59 will automatically be swung counterclockwise and the

clutch member

54, 55 will be disengaged.

Rearwardly of the plate 66 is a vertically extending plate 69 (FIG. 2) that is regularly supported at its lower end on a cross frame member 70 that, in turn, rigidly connects the side plates 17 rearwardly of sprocket wheel 35. This plate 69 is formed with a vertically extendnig, but slightly forwardly inclined slot 73.

A cross bar 74 extends between and is carried by the rear end portions of the plates 25 that mount the row of cylinders 32. This cross bar 74 extends through slot 73 and when bar 74 is at the upper end of slot 73 the upper and lower runs of the endless row of units 32 are horizontally extending (FIG. 2) so as to be parallel with the upper run of conveyor 11.

Pivotally secured at 75 (FIG. 2) to plate 69 at a point about midway between the upper and lower ends of slot 73, but to the rear side thereof, is a latch bar 76. The forward side of the latch bar 76 at its lower end is formed with a notch 77 providing a downwardly directed shoulder 78. The lower end of said latch bar is biased forwardly by a spring 79.

When bar 74 is moved to the lower end of slot 73, upon downward swinging of the rear ends of plates 25, the bar 74 will cause the lower end of the latch bar 76 to swing rearwardly until the bar 74 enters notch 77, at which time the shoulder 78 at the upper end of the notch will engage over the bar 74 to hold the row of cylinders 32 elevated and inactive. Since the clutch will automatically have been disengaged, the cylinders 32 will be stationary and inoperative, although the row may manually be moved longitudinally thereof.

When the upper end of the latch bar 76 is moved forwardly, the bar 74 will be released and the units 32 will again be moved since the

clutch members

54, 55 will automatically be re-engaged.

This construction provides a shaft 20 that tiltably mounts the row of units 32, and a shaft 34 includes the clutch for engaging and disengaging the units 32 with respect to the source of power without stopping the conveyors 11, thus enabling the printing or discontinuance of printing without stopping the delivery of fruit to the discharge point, and it further enables servicing the units 32, as desired, without stopping the operation of the remainder of the machine. Obviously, only a single row machine may be used where a relatively small volume of articles are to be printed upon.

Insofar as the printing operation is concerned, it is undesirable that the printing powder, which may be sufficiently free to pass through a 325 line screen, should be ejected into the atmosphere in the event a fruit body or other article carried by the conveyor is not in a position to receive it. As already stated, and as will be hereafter explained, more in detail, the cylinders each carry a printing head, and each head has a printing screen.

It should be mentioned here that the air gap in which the electrostatic powder carrying lines of force are estahlished by the potential differential is relatively small, and if it is substantially increased there will be no discharge.

Referring to FIGS. 2, 7,. 8, the sprocket chains 30 carrying the units 32 are clearly indicated, and on one of the inner sides of one of the stationary plates 17 is a cam track 81 (FIG. 2) that is adapted to support a roller 82 that, in turn, is secured to and that projects laterally from the lower cylinder 83 of each unit 32. The lower cylinder 83 of each unit 32 is a vertically reciprocable cylinder within an upper cylinder 84, and both cylinders are tubular.

The structure of the units 32 is the same, and said units will be described in the position shown in FIGS. 7, 8 which may be substantially a printing position in which the printing head is on the lower end of each lower cylinder 83.

In the upper run of the endless row, the units 32 are inverted with respect to the positions thereof as shown in FIGS. 7, 8.

The upper cylinder 84 has a head or closure 85 at its upper end, to which the pair of chains 30 are connected, and a vertical shaft 88 rotatably extends through said head 85 centrally thereof, which shaft projects above head 85 and has a horizontally disposed relatively thin sprocket wheel 89 secured to its upper end. The lower end of shaft 88 is of reduced diameter as at 90, and slidably projects into a vertically disposed upwardly opening recess 91 formed in the upper enlarged end 92 of a rotary shaft 93 in cylinder 84.

An upper clutch member 94 is secured by a pin to the lower end portion of shaft 88 against a downwardly facing shoulder 95. The clutch member 94 at its lower portion is shown in elevation for clarity, as is the portion of the lower clutch member adjacent to the engaging surfaces of the two. Extending around and partially over the clutch member 94 is a cylindrical element 96 having 6 a radially inwardly projecting flange 97 at its upper end. Said flange extends slightly over clutch member 94, and a radially outwardly directed flange 98 at its lower end that, in turn, is seated in a recess formed in the inner upper corner of the lower cylinder 83 of the unit 32.

A lower clutch member 100 is threadedly secured to the upper end of the head 92 of the lower shaft 93, which nut is :against a lock washer 99 that, in turn, is against the inner race of a ball bearing 104. The bearing 104, in turn, is seated against an upwardly facing shoulder formed around head 92 of shaft 93.

The outer race of bearing 104 (FIG. 2) is held between a split ring 102 seated in a radially opening recess formed in the upper end of the lower cylinder 83, and an upwardly facing shoulder formed in the inner side of said lower cylinder.

Upper and lower bearings 105 carried by the cylinder 83 adjacent to its ends, reciprocably support the lower cylinder 83 within the upper cylinder 84.

A helical spring 101 reacts between head 85 of the upper cylinder 84 and the flange 98 on the member 96 to yieldably urge the lower cylinder 83 downwardly, and to also yieldably urge the shaft 88 in a direction in which the hub of sprocket wheel 89 is against the head 85 of the upper cylinder.

A printing head, generally designated 106 is carried on the lower end of the lower cylinder 83. Said printing head has a cylindrical lower end 107 coaxial with shaft 93, and which lower end 107 is connected by a horizontal radially inwardly directed wall 108 with the lower end of a tubular portion 109, that, in turn, is pinned or otherwise suitably connected at its upper end with the lower cylinder 83 at a point spaced well above the terminating lower end of said cylinder 83. The outer surface of the tubular portion 109 is of the same diameter as the maximum outer diameter of lower cylinder 83.

A collar 110 is threadedly secured on the lower end of the cylinder 84 having a radially inwardly directed flange around its lower edge engaging the lower end edge of said upper cylinder 84. This collar is split to provide a vertical passageway 111 (FIG. 7) in one side that is adapted to be positioned to pass the shaft 112 that supports roller 82 on the lower cylinder 83. A spacer is around said shaft 112 and spaces the roller from the lower cylinder, and space 111 in collar 110 is sufficient to pass the spacer. A vertical slot 103 formed in the side of upper cylinder 84 opens outwardly of the lower end of said cylinder, and the shaft 112 and its spacer are reciprocable in said slot. Thus, when the collar is rotated until the open ended slot 111 in its side is in register with slot 103 the lower cylinder and its assembly may be freely slipped out of the upper cylinder 84. When the collar is rotated so slot 103 is out of alignment with slot 111, the collar will prevent the separation of the

cylindrical portions

83,84.

A 'ball bearing 113 is secured around a reduced diameter lower end portion of shaft 93 and against a downwardly facing shoulder on said shaft. The lower end portion of shaft 93 is vertically drilled and tapped for a screw member 114 that, in turn, is coaxial with shaft 93 and that is threadedly secured at its upper end in a threaded recess formed in the lower end of shaft 93.

The screw member has an annular, radially outwardly projecting flange 115 that is tight against the lower side of the inner race of bearing 113 and an eccentrically positioned neck 116 projects below said flange having a genenally ball-like head 117 at its lower end, also eccentrically positioned relative to the axis of shaft 93. The neck 116 and head 117 are integral with the screw member 114.

A horizontal pin or shaft 118 extends transversely across, and is secured at its ends, to the lower end of the lower cylindrical portion 83 slightly above the level of wall 108 and ball bearings on shaft 118 r-otatably support a brush mount 120 (FIG. 7) for oscillatory movement of a mohair brush 123 that is cemented to the lower convex surface of a backing plate 124 with the bristles of said brush projecting outwardly and following the cylindrical curvature of a radius developed about the axis of shaft 118. Said brush mount 120 is formed with a pair of spaced opposed plates 125 that are at opposite sides of the ball-like head 117 on screw member 114, and which plates are above the shaft 118. The backing plate 124 is provided with an upwardly extending shank 126 that is rectangular in cross section. The upper end of said shank is removably secured by a set screw 127 within a downwardly opening flat sided recess formed in a downward extension of the mount 120 that projects below the shaft 118.

The ball bearings mounting shaft 118 are designated 119.

Secured to one of side plates 25 at the level of the sprocket wheel 89 is a rack 128 (FIG. 2) the teeth of which are vertical and relatively long, with well rounded outer ends. As the lower run of the chains move from right to left, as seen in FIG. 2, the teeth of the sprocket wheel 89 at the upper end of each of the units 32 will engage the teeth of said rack and will cause rotation of the

shafts

88, 93, and said teeth on the sprocket wheel will remain in engagement with the teeth of the rack during any vertical movement of the sprocket up or down. However, in the event the cylinder 83 and the printing head thereon are lowered, due to there being no article, such as indicated at 130 in FIG. 2, to be printed upon, the printing head, and lower sprocket wheel 89, cylinder 83 will automatically move downwardly a sufiicient distance to disengage the teeth of sprocket wheel 89 from rack 128 and the actuation of the brush 123 would cease until the teeth of the sprocket wheel 89 were again in engagement with the rack 128.

The printing powder that is used in the present invention is dry, or at least the particles are surface-dry, and a supply there-of is held in the enlarged lower end of the printing head 106, which head is removably secured to the lower cylindrical section 83 by a pin 82, and a sealing washer may be positioned between the upper edge of tubular portion 109 and a downwardly facing shoulder on the lower cylinder. 1

The lower end of the enlarged portion 107 of the lowermost portion of unit 32 is open, and an annular non-conductive ring 133 is threadedly secured to said lower end, which ring is formed with radially inwardly projecting flange 134 extending below and across the lower edge of said portion 107. Between flange 134 and the portion 107 is a non-conductive NYLON screen 135 that is cemented or otherwise suitably secured to the lower side of a circular, non-conductive plate 136, that, in turn, is :below a circular disc 137. A cylindrical member 138 is clamped by flange 134 of ring 133 between the assembly of discs 136, 137 and screen 135 and the wall 108 of the printing head, the said wall being recessed at 139 to position the cylindrical member 138 and to hold it concentric with the cylindrical wall 107 of the printing head and coaxial with shaft 93.

The screen 135 is stopped out by a suitable agent except for the design, printing or coating to be transferred to articles 130, and the discs 136, 137 are formed with registering openings exposing the portion of the screen having the unobstructed mesh openings. Brush 123 is adapted to rapidly sweep back and forth across the upper side of the portion of the screen 135 that is so exposed to not only force the printing powder through the mesh openings in said screen, but to evenly distribute the powder on the exposed portion of the screen.

Flange 134 itself may serve to space the upper surfaces of the articles from the screen, but in addition, soft resilient, compressible, non-conductive pads 132 of foam or sponge rubber at opposite sides of the portion of each screen that has the unobstructed mesh openings, will prevent any injury to the articles 130, and will also function to space the screen from said articles, although in any even-t this spacing is maintained substantially constant at a distance to insure the most elficient deposit of powder on the article.

From the foregoing description, it will be seen that the articles 130 will be charged with either a negative or positive charge from voltage source 16 and the brush mount will have the opposite charge, and when the article and the screen are brought into opposition with each other at their closest point (which is where the teeth of rack 128 and the teeth of sprocket wheel 89 are in engagement) the brush 123 will be rapidly actuated to sweep back and forth across the upper portion of screen 135 that carries the unobstructed mesh openings defining the design and the powder will be conducted onto the adjacent surface of each article 130, where it will remain adhered by residual electrostatic force until fixed on the surface of each article.

The cylindrical member 138 is formed with recesses 140 (FIG. 8) in opposite sides thereof opening to the upper disc 137 which openings are positioned to permit the powder around the member 138 to pass into the space in which the brush oscillates, but the member will function as a baffle to check the bodily movement of the powder in the enlarged lower end of each unit 32 when the units move horizontally and upwardly to the upper run of chains 30, and then down again to the lower run.

Each of the units 32 will follow the same path and the retraction and extension of the lower cylinder and printing head thereon will be the same at the same points along said path of travel.

When the units are inverted, as they will be when moving along the upper run of their endless path, and when they are substantially horizontal at the horizontal ends of said path, the cylinders 83 may be in extended positions under the influence of the spring 101 that is in each unit 32. However, when the units start moving downwardly toward the upper row of holders of conveyor 11, the roller 82 that is connected with the lower cylinder 83 of each unit 32 will engage the cam track 81, and the cylinder 83 will be retracted, thus compressing spring 101, which also will result in moving

shafts

88, 93 in the same direction as the lower cylinder 83. The movement of the

shafts

88, 93 is due to the engagement between the upper portion of clutch 94 with the flange 97 of the spring engaged member 96, (FIG. 2).

The upper surface or edge of cam track 81 on which the cam follower or roller 82 rides from right to left as seen in FIG. 2 is formed with a gradual downwardly inclined dip 149 leading toward the printing station 148, resulting in a downward extension of the lower cylinder 83, and as the yieldable members or pads 132 on the lower side of each printing head 106 engage each article 130, the pads will be slightly compressed until the desired spacing between the screen 135 and the surface of article 130 opposed thereto is reached, and at or just before this point is reached, the gear 89 at the upper end of the unit will engage the teeth of the rack 128 and the brush 123 will relatively rapidly sweep back and forth across and in engagement with the upper surface of the screen 135 where the open mesh design has been formed. The article 130 and brush 123 have been oppositely charged at a sufiicient voltage to establish an electrostatic field between said screen and the surface of the articles that will immediately carry the powder across the gap between the screen and said surface and to deposit said powder onto said surface in exactly the same design as that of the open mesh portion of the screen.

This space between the screen and articles and the voltage are such that no arcing will occur.

After the powder in the desired design has been deposited on each article, the conveyor 11 carries the articles below a fixing station generally designated 150 (FIG. 1) where a fixing agent is ejected onto the previously deposited powder to fix it against removal.

A discharge nozzle 153 (FIG. 1) is supported over each row of articles 230 as they pass from below the printing heads 106 after having been printed upon. Preferably an atomized spray of the fixing agent is ejected onto the powder that has been deposited on each article as the article passes below the nozzle. Suitable liquid pres sure and air lines may lead to each of the nozzles. In FIG. 1 an air pressure line 154 extends to each nozzle for atomizing and ejecting a liquid mixture supplied to the nozzle through lines 155, 156, and a valve 157 (FIG. 3) in line 154 may be actuated by a cam 158 on shaft 49, and a cam follower 159 to cause ejection of the atomized liquid mixture onto each article 130 as each article passes below the nozzle.

Where the conveyor 11 carries the articles past the nozzle at a relatively high rate of speed, a valve controlling the ejection of the air and liquid may be continuously open, but closed only when the conveyor 11 and printing heads are inoperative. The spacing between the holders 8 is quite slight, and it is obvious that where they move past the spray nozzles upwardly of two hundred a minute, or even less, there is no necessity for closing the pressure lines to the nozzles between the passage of each holder and article 130 past each nozzle.

Referring to FIGS. 13, 14 in which modified holders, similar to holders 8 are shown, these are generally designated 143 and each is nonconductive and has downwardly and inwardly tapered side walls adapted to substantially center an object in the holder over and in engagement with a fiat spiral electrically conductive spring 145 that is connected at its lower end with a conductor 146 secured to and projecting below the lower end of the holder.

This conductor 146 is adapted to slidably engage conductor 13 that is shown in other views, so that an article held in the holder will receive a charge of electricity.

The chains 144 substantially correspond to the chains carrying the holders 8.

Spring 145 is readily compressible under a relatively light weight object so that the article or object therein will always be supported on the walls of the holder.

I claim:

1. Apparatus for marking articles comprising:

(a) a row of article supports, each adapted to support thereon an article to be marked;

(b) a row of powder supports, each adapted to contain a body of marking powder;

(c) row supporting means respectively supporting said rows for movement longitudinally thereof in separate paths of travel, and means connected with said rows for so moving them;

(d) guide means for successively guiding such article support and each powder support into registration with each other, at a point in said paths;

(e) each powder support including a stencil screen on which each body of powder is adapted to be supported and which screen is in spaced opposed relation to each article support when they are in registration with each other at said point;

(f) an electrical circuit in which said article and powder supports are operatively connected at said point for establishing an electrical potential therebetween;

(g) powder spreading means supported on each powder support for movement into engagement with the powder to be supported on the latter and with each screen and across the latter for substantially uniformly distributing such powder on said screen and for forcing the powder through the mesh openings in said screen;

(h) driving means including driving and driven elements movable from an inoperative position out of driving relation to each other to an operative position in which said driving and driven means are in driving relation, and vice versa, for so moving said powder spreading means when said driving and driven means are in said operative position and for discontinuing said movement when said driving and driven means are in said inoperative position;

(i) said driven means being responsive to movement into said operative position only under the influence of an article on an article support at said point as said article support moves past said point whereby said powder spreading means will be inoperative in the absence of an article on an article support at said point.

2. In apparatus as defined in claim 1:

(j) means for so operatively connecting said powder supports and said article supports in said circuit at said point only upon movement of said powder supports and said article supports therepast;

(k) said article supports each being of non-conductive material including a yieldable conductor yieldably engageable with each article when the latter is carl'l6d by each article support.

3. Apparatus for marking articles comprising:

(a) a row of article carriers, each adapted to carry an article to be marked;

(b) a row of powder carriers, each adapted to carry a body of marking powder for marking said articles;

(c) separate row supporting means for respectively supporting said rows for simultaneous movement of the pair of rows longitudinally thereof one over the other for a finite distance in separate paths for successive movement of each article carrier and one of said powder carriers into vertically spaced, registering relation along said paths;

(d) means for electrostatically transferring powder from each body of powder onto an article, when such body is carried by each powder carrier and such article is in each article support and when said rows are so moved in said paths;

(e) single power means operatively connected with said rows of carriers for simultaneously moving them 'in said paths at the same rate of speed;

(-f) means supporting one of said row sulpporting means for bodily movement thereof away from the other of said row supporting means and back again to its original position prior to such movement;

(g) means actuated by said bodily movement of said one of said row supporting means for automatically disconnecting the row of powder carriers from said single power means upon such bodily movement of said one of said row supporting means away from the other and for automatically reconnecting the said row of powder carriers with said power means upon a reverse bodily movement of said one of said row supporting means back to its original position relative to the other row supporting means.

4. The method of marking discrete articles of different vertical thicknesses that comprises the steps of (a) moving a row of said articles in spaced relation in one direction in a path extending longitudinally of said row and supporting said articles from below during such movement with their lowermost sides at a uni-form predetermined level whereby the upper surfaces of said articles will be at different levels according to'the different thicknesses of said articles;

(b) moving a body of marking powder downwardly into uniformly spaced relation above and into alignment with successive articles at a point in said path during movement of each article past said point and while.

the lower side of each article is at said predetermined level;

(c) transferring powder from the body spaced above an article at said point onto said upper surface of such article by connecting said body and the article spaced therebelow in an electrical circuit providing electrostatic lines of force across the space between them to conduct said powder from the body at said point for deposit onto the upper surface of the article therebelow, and then (d) adhering the powder so deposited on said upper surface against accidental removal therefrom, and

(e) physically forcing powder from such body into said lines of force when said body is in alignment with an article at said point.

5. The method of marking discrete articles of different vertical thicknesses that comprises the steps of:

(b) moving a row of separate bodies of marking powder longitudinally thereof in the same direction as the movement of said row of articles and at the same rate of speed and in a position spaced above said row of articles with each of said bodies in vertical alignment with one of said articles;

(c) moving each of said bodies downwardly at a point in said path to a uniform spaced position above the upper surface of the article in vertical alignment therewith while the underside of such article is at said predetermined level, and during said movement of said rows of articles and bodies in said same direction;

(d) transferring powder from each body at said point to the article therebelow across the space between them, and during movement of said rows in said same direction, by connecting each body and the article spaced therebelow in an electrical circuit providing electrostatic lines of force across said space to conduct said powder from each body at said point for deposit thereof onto the upper surface of said article, and then,

(e) adhering the powder so deposited onto said upper surface to the latter against accidental removal therefrom.

6. The method as defined in claim that includes the step of:

(f) physically urging powder from said body into said lines of force when a body is in vertical alignment with an article at said point.

7. Apparatus for marking articles comprising:

(a) a horizontally extending row of article carriers, each adapted to support thereon an article to be marked;

(b) power means operatively connected with said article carriers for simultaneously and continuously moving them longitudinally of said row in one direction past a predetermined point;

(c) a horizontally extending row of powder carriers, each adapted to carry a body of marking powder for marking said articles;

(d) supporting means supporting said row of powder carriers spaced above and substantially parallel with said row of article carriers with each of said powder carriers in said row vertically aligned and vertically spaced over one of said article carriers and with the article adapted to be supported thereon;

(e) means operatively connecting said powder carriers with said power means for simultaneously and continuously moving said powder carriers in a straight line longitudinally of the row thereof in the same direction as the direction of movement of said row of article carriers and at the same rate of speed as that of the latter; 7

(f) each of said powder carriers including a powder supporting screen having mesh openings facing and spaced from the article carrier and articles therebelow through powder of said body is adapted to be moved for conduction across the space between said screen and articles therebelow for deposit onto said article when the latter is on one of said article carriers;

(g) means at said point for establishing an electrostatic field in the space between each screen and an article on an article carrier that is therebelow for conducting the powder to move through the mesh openings in each screen onto one of said articles;

(h) means for moving each powder carrier including the screen carried thereby toward the article carrier and article thereon, at 'said point to a position in which the screen of each carrier is substantially uniformly spaced above the upper surface of the article on the article carrier that is therebelow;

(i) a yieldable, relatively soft pad of resilient electrical insulation material on said carrier adjacent to opposite edges of each screen for engaging the article on the article carrier therebelow and for uniformly spacing said powder carriers from the articles therebelow at said point free from injury to said articles.

8. In apparatus as defined in claim 7:

(j) powder moving means carried by each powder carrier in a position over the screen in each of said powder carriers and in engagement with the screen therebelow supported for movement with each screen longitudinally of said row of powder carriers and for movement downwardly at said point with each screen;

(k) and means to move said powder moving means relative to the screen in engagement therewith at said point for moving powder on said screen through the mesh openings of the latter upon said movement.

9. Apparatus for marking articles, comprising:

(a) a row of article carriers, each adapted to carry an article to be marked;

() separate row supporting means for respectively sup porting said rows of article carriers and powder carriers for movement of each of said rows longitudinally thereof in the same direction in separate paths and in positions relative to each other for successive movement of each article carrier and each powder carrier into spaced, registering relation at a point along their paths;

(d) means for electrostatically transferring powder at said point from each body of powder onto an article when said body and article carrier and a powder carrier to said registering spaced relation of said carriers;

(e) single power means connected with said row of article carriers and said row of powder carriers for effecting the aforesaid movement thereof to and past said point;

(f) said separate row supporting means including a pair of frame members respectively carrying said row of article carriers and said row of powder carriers for said movement of each row longitudinally thereof and relative to the frame member carrying each row;

(g) said means supporting one of said rows for bodily movement away from the other of said rows comprising pivot means pivotally connecting said pair of frames at a point adjacent to one of the ends of said rows for swinging the frame member carrying said powder carriers away from the other frame member, said row of powder carriers and the frame member carrying the same being swingable as a unit about said pivot means;

(h) each of said rows comprising one of the longitudinally extending rows of an endless conveyor that includes endless chains respectively connected to said row of article carriers and said row of powder carriers;

(i) said pivot means being a shaft, and coaxial sprocket wheels, carried by said shaft over which one of the ends of each of said endless conveyors extends;

(j) said power means being connected with said shaft for rotating the latter including said sprocket wheels, whereby the endless chain carrying said article supports may continue movement of said article carriers when said row of powder carriers is swung away from said row of article carriers.

10. In apparatus as defined in claim 9:

(k) clutch means on said shaft releasably connecting the sprocket wheel carrying said row of powder carriers with said shaft for actuation of the powder carriers for movement thereof by said single source of power;

(1) means connected with said clutch means and with the frame member carrying said powder carriers automatically actuateable for disconnecting said clutch means to permit free rotation of the sprocket over which the chain supporting the powder carriers extends, whereby the endless conveyor that includes said powder carriers will be stationary when said clutch means is disconnected. 11. In apparatus for electrostatically marking articles with a marking powder, the improvement that comprises:

(a) a container having a powder supporting section provided with a stencil screen comprising one wall of said container, a portion of said screen being perforated for passage of said marking powder therethrough;

(b) spacing and positioning means on said container for engagement with the article to be printed upon, and for spacing said portion of said screen a predetermined distance from the surface of said article in a position opposed to said surface;

(c) means for establishing an electrical potential between said portion and said surface when said portion of said screen is at said predetermined distance from and in opposed relation to said surface of said article, for conducting powder on said portion onto said surface when powder is in said section;

(d) yieldable means carried by said container for yieldably holding said portion of said screen at said predetermined position relative to the surface of said article when such article is supported in a position to be engaged by said spacing means;

(e) means for positioning an article for engagement by said spacing means;

(f) said container including a tubular body and said section being tubular and in slidable telescopic coaxial relation to said tubular body with said section projecting from said tubular body, and said screen being in the projecting outer end of said body;

(g) said yieldable means being a spring reacting between said tubular body and said section, urging said tubular section in a direction outwardly of said tubular body; and

(h) said means supporting said container for its movement along said path being connected with said tubular body and being restricted to movement in a fixed path against movement in a direction transversely thereof and the axis of said tubular body and said tubular member being at a right angle to said last mentioned path, whereby said section may yield toward said last mentioned path upon the outer end thereof engaging an article.

References Cited by the Examiner UNITED STATES PATENTS 1,784,912 12/1930 Scott.

2,484,671 10/ 1949 Bauman.

3,081,698 3/ 1963 Childress et al.

3,202,092 8/ 1965 Childress.

3,202,093 8/ 1965 Childress.

3,218,967 11/ 1965 Childress.

3,228,326 1/1966 Childress 10l114 ROBERT E. PULFREY, Primary Examiner. DAVID KLEIN, Examiner.

E. S, BURR, Assistant Examiner.

Claims

1. APPARATUS FOR MARKING ARTICLES COMPRISING: (A) A ROW OF ARTICLE SUPPORTS, EACH ADAPTED TO SUPPORT THEREON AN ARTICLE TO BE MARKED; (B) A ROW OF POWDER SUPPORTS, EACH ADAPTED TO CONTAIN A BODY OF MARKING POWDER; (C) ROW SUPPORTING MEANS RESPECTIVELY SUPPORTING SAID ROWS FOR MOVEMENT LONGITUDINALLY THEREOF IN SEPARATE PATHS OF TRAVEL, AND MEANS CONNECTED WITH SAID ROWS FOR SO MOVING THEM; (D) GUIDE MEANS FOR SUCCESSIVELY GUIDING SUCH ARTICLE SUPPORT AND EACH POWDER SUPPORT INTO REGISTRATION WITH EACH OTHER, AT A POINT IN SAID PATHS; (E) EACH POWDER SUPPORT INCLUDING A STENCIL SCREEN ON WHICH EACH BODY OF POWDER IS ADAPTED TO BE SUPPORTED AND WHICH SCREEN IS IN SPACED OPPOSED RELATION TO EACH ARTICLE SUPPORT WHEN THEY ARE IN REGISTRATION WITH EACH OTHER AT SAID POINT; (F) AN ELECTRICAL CIRCUIT IN WHICH SAID ARTICLE AND POWDER SUPPORTS ARE OPERATIVELY CONNECTED AT SAID POINT FOR ESTABLISHING AN ELECTRICAL POTENTIAL THEREBETWEEN; (G) POWDER SPREADING MEANS SUPPORTED ON EACH POWDER SUPPORT FOR MOVEMENT INTO ENGAGEMENT WITH THE POWDER TO BE SUPPORTED ON THE LATTER AND WITH EACH SCREEN AND ACROSS THE LATTER FOR SUBSTANTIALLY UNIFORMLY DISTRIBUTING SUCH POWDER ON SAID SCREEN AND FOR FORCING THE POWDER THROUGH THE MESH OPENINGS IN SAID SCREEN; (H) DRIVING MEANS INCLUDING DRIVING AND DRIVEN ELEMENTS MOVABLE FROM AN INOPERATIVE POSITION OUT OF DRIVING RELATION TO EACH OTHER TO AN OPERATIVE POSITION IN WHICH SAID DRIVING AND DRIVEN MEANS ARE IN DRIVING RELATION, AND VICE VERSA, FOR SO MOVING SAID POWDER SPREADING MEANS WHEN SAID DRIVING AND DRIVEN MEANS ARE IN SAID OPERATIVE POSITION AND FOR DISCONTINUING SAID MOVEMENT WHEN SAID DRIVING AND DRIVEN MEANS ARE IN SAID INOPERATIVE POSITION; (I) SAID DRIVEN MEANS BEING RESPONSIVE TO MOVEMENT INTO SAID OPERATIVE POSITION ONLY UNDER THE INFLUENCE OF AN ARTICLE ON AN ARTICLE SUPPORT AT SAID POINT AS SAID ARTICLE SUPPORT MOVES PAST SAID POINT WHEREBY SAID POWDER SPREADING MEANS WILL BE INOPERATIVE IN THE ABSENCE OF AN ARTICLE ON AN ARTICLE SUPPORT AT SAID POINT.