GB2180195A - Using ink drop devices to mark out work - Google Patents

Abstract

An apparatus for marking the surface of an article, (such as a crystal goblet 100) for subsequent cutting, comprises a marking station 14, a turntable 19 for rotating the article at the marking station, ink jet printing means 50 at the marking station for discharging ink onto the article in a direction transverse to the axis of rotation of the article, and a motorised screw 43/44 for moving the printing means (50) in a direction substantially parallel to the axis of rotation of the article. <IMAGE>

Description

SPECIFICATION An apparatus for marking the surface of an article This invention relates two an apparatus for marking the surface of an article.

The invention is particularly concerned with marking a glass article to enable a glass cutterto ac curately cut the surface of the glass to produce so- caljedcutglassorcutcrystal.

Forthe accurate cutting of glass, in particular crystal, it is necessary to mark the piece to be cut with indicia corresponding to a desired pattern. At present, it is necessary to mark the piece by manual means.

It will be appreciated that manually marking crystal is not only relatively slow but is also very boring for the operator marking the glass.

It is an object ofthe present invention to provide an apparatus which permits the automated marking of glass or crystal articles.

The invention therefore provides an apparatus for marking the surface of an article, comprising a marking station, meansfor rotating the article atthe marking station, inkjet printing means at the marking station for discharging ink onto the article in a direction transverse to the axis of rotation of the article, and means for moving the printing means in a direction substantially parallel to the axis of rotation ofthe article.

By providing appropriate controlling means, which is preferably a microcomputer, a pattern of both circular lines as well as spaced apart vertical lines may be marked on the substrate.

The invention will be understood in greater detail from the following description of a preferred emb odimentthereofgiven by way of example only and with reference to the accompanying drawings in which: Figure 1 is perspective view of an apparatus according to the invention: Figure 2 is a perspective detail view of a first part of the apparatus of Figure 2 in a first position of use; Figure 3 is the part of the apparatus of Figure 2 in a second position of use; Figure 4 is a perspective detailed view of a second part ofthe apparatus of Figure 1 in a first position of use; Figure5isthe part ofthe apparatus of Figure 4 in a second position of use; and Figure 6is a plan view a discforuse in theapparatus of Figure 1.

Referring now to the drawings, there is shown an apparatus 10 according to the invention which comprises a fixed housing 11, a carousel 12 mounted for rotation about a vertical axis atop the housing 11, an article centering station 13 and an article marketing station 14.

The housing 11 has various mechanical and hydraulic devices which are necessary for the successful operation ofthe apparatus 10 but which devices will not be described here in any great detail as they will be understandableto those skilled in the art.

The carousel 12 has four sections 15,16,17 and 18, each section 15-18 having a respective set of four turntables 19,20,21 and 22 thereon. The housing 11 contains a motorfor rotating the carousel 12 in a clockwise direction, as viewed in the drawings, and further motors for rotating each set ofturntables 1922 independently of the carousel 12 about respective vertical axes. Each of the turntables 19-22 of a set has an open mouthed pipe 23 the purpose of which will be described later. Each ofthe pipes 23 of a set of turntables is connected by appropriated means to a respective tube 24, the tube 24 being connected to a vacuum pump (not shown).

The purpose of the centering station 13 (Figures 2 and 3) is to centre the article, in this case a circularly symmetrical crystal goblet 100. The centering station 13 is rigidly suspended above the carousel 12 by means of rods 25, the rods 25 supporting a fixed base 26 having a pair of hydraulic rams 27, 28 fixed thereon. Also mounted on the base 26 is a pairofvertical rods 29a, 30a along which are adapted to slide respective guide elements 29,30 fixed to a movable plate 31. The rams 27,28 are attached to the movable plate31 sothat byoperation ofthe ramsthe plate31 may be moved up or down by the elements 29,30 sliding on the rods 29a, 30a. Mounted on the movable plate 31 are four centering devices 32,33,34and 35.Each ofthe devices 32-35 is identical so that the operation of only one of them vizthedevice32will be described.

The device 32 comprises a housing 36 having three equi-angularly shaped toothed flanges 37 mounted thereon for sliding radially ofthe housing 36. Depending from each flange 37 is a vertical leg 38 the free endofwhich leg hasagrommet39thereon.The housing 36 has a hydraulic motor therein which receives hydraulic power via a pipe 24a and which motor serves to move three elements 40 simu ltaneously into and out ofthe housing via respective apertures 41. Each of the elements 40 has a toothed part 42 adapted for engaging with the a respective toothed flange 37 in a manner of a pairofengaging ratchets.Thus, movement ofthe elements 40 causes acorrespondingsliding movementoftheflanges37, resulting in the legs 38 moving simultaneouslytow- ards orawayfrom the axis ofthe pipe 23, which axis is located centrally relative to the housing 36 and legs 38. The hydraulic motor ofthe housing 36 is controlled via pressure sensors (not shown) associated with the legs 38.

The marking station 14(Figures4and 5) comprises a base 40 fixed to the housing 1 which base 40 supports a wall 41 and a cover42. Also mounted on the base 40 is a vertical screw element44 and a pairof vertical guide rods 45,46. A platform 47 is also providedwhich platform has holesthereinto enable the screw element 44 and the guide elements 45, 46to pass therethrough. The hole which enables the screw element 44 to passtherethrough is screw threaded and thus, rotation of the screw element 44 raises or lowers the platform 47 relative to the base 40. Rotation of the screw element 44 is achieved by means of a stepping motor43 housed on the cover 42.Respective guide sleeves 45a, 46a are provided on the platform 47 to slide on the guide rods 45,46.

Mounted on the platform 47 are four print heads 50,51,52 and 53. The print heads are ofthetype man ufactured by American Technologies Limited of Essex House, Bridle Road, Bootle, Merseyside L30 4UE, UK and sold underthe name DominoAmjet.

Essentially, each print head 50-53 comprises a gun body 54 which serves to discharge a stream oftiny drops ofinkofequal size from an ink reservoir (not shown) broken up by ultrasonic oscillation. As the drops are formed, they pass through a charging elec- trode and thus collect variable electrostatic charge.

The drops then pass through a pairofplates 55 which provide a constant high voltage field. The field causes each dropletto be deflected by an amount proportional to the size of its electrostatic charge. If the elecrostatic charge is such that the plates 55 do not produce a deflection, each droplet is collected in a gutter 56 for recycling through the gun body 54.

In the drawings, each print head 50-53 is shown in simple diagramaticform and no specific detail as to how the print heads 50-53 operate will be provided here as such information is available in technical literature supplied by American Technologies Limited.

In use,theapparatus 10functionsasfollowsrin which, it must be appreciated, onlythe movement and operations relating to one turntable, vizturntable 19, will be described. The movement and operations relating to the remaining turntables 20 to 22 ofthe same set are similar and occur simultaneously with those oftheturntable 19.

In Figure 1,the goblet 100 is shown in an inverted condition ontheturntable 19. The goblet 100 is loaded manually onto the turntable 19 but it could be possible to use automatic loading. During loading theturntable 19 its stationary at the location shown in Figure 1, which constituts a loading station.

After an appropriate period oftime has elasped, in otherwordstoallowformanual loadingofthere- maining turntables 20-22 immediately to the left of the turntable 19 as viewed in Figure 1 ofthe drawings, avacuum is created in the goblet 100 by the action ofthe vacuum pump drawing the airtherefrom via the pipe 23. The carousel 15 is now moved 90 in aclockwisedirection untiltheturntable 19is directly below the centering device 32,whereupon the carousel is stopped. The purpose of the vacuum is to prevent the goblet 100 from falling over during movement of the carousel 15.

Air is now allowed to enterthe goblet 100 to enable movement of the goblet 100 on the stationaryturn table 19. The legs 38 are lowered by the action ofthe hydraulic rams 27,28 in lowering the movable plate 31. By means ofthe hydraulic motor and the interac- tion of the toothed parts 42 and the toothed flanges 37,the legs 38 are moved inwardly so that the grommets 39 contact the surface ofthe goblet 100.

Should the goblet 100 be off-centre relative to the pipe23,then the legs 38 will move the goblet 100 and place it centrally relative to the pipe 23. When no further movement ofthe legs 38 is possible, the pres sure sensors activate the hydraulic motorto move the legs 38 away from the goblet 100 and activate the rams 27,28 to raise the movable plate 31.

Avacuum is again applied to the goblet 100, and the carousel 12 is moved 90 in a clockwise direction untii the axis oftheturntable 19, and thus the axis of the goblet 100, is in line with the print head 50 wherein upon the carousel is stopped. With the vacuum still applied, the turntable 19 is activated so as to rotate and the print head 50 is activated to discharge a jet of ink onto the goblet 100 to markthe goblet 100 with a predetermined pattern. The way the pattern is marked on the goblet 100 will be described in more detail below.

The ink is discharged in a direction transverse to and intersecting the axis of rotation ofthe turntable 19. If the ink is discharged continuously, and the print head 50 is maintained at a fixed height relative to the base 40, a circumferential circle is marked on the sur face of globlet 100. If the ink is intermittentlydischar- ged from the print head 50 once or several times per revolutionoftheturntable 19 whilethe print head 50 is slowly raised by the rotation ofthe screw element 44, then one or more vertical lines may be marked.

When the desired pattern has been marked on the goblet 100, the carousel 12 again moves in a clockwise direction to an unloading station which is ata position 90 anticlockwise of that shown in Figure 1 and the goblet 100 is unloaded after the vacuum is removed. The carousel is now moved 90" to the position shown in Figure 1 and a new goblet is placed on the turntable 19 and the cycle is repeated.

Itwill be appreciated during normal operation of the apparatus 10, all ofthe sets ofturntables 19-22 are in use so thatfourgoblets at the centering station 13 are processed simultaneously with the marking of four other goblets at the marking station 14 and the loading and unloadingofothergobletsattheloading and unloading stations.

It is preferred that the apparatus 10 be underthe control of a mirocomputer which monitors and controls all of the events necessaryforthe successful operation of the apparatus 10. In particular, it is preferred that each print head 50-53 be under the control of the microcomputer. In a most preferred embodiment of the invention, the microcomputer may be preprogrammed with a plurality of separate sub programmes forthe control ofthe print heads 50-53.

For example, it would be possible to key into the microcomputerthe product number associated with a particular pattern to be marked on the article which microcomputerwould then operate the print heads and the marking station in an appropriate manner.

Thus, for example, if it were desired to markthe goblet 100 with three concentric rings at specific intervals apart, the microcomputer would control the action ofthe stepping motor 43 causing itto holdthe print head 50 at a particular level relative to the base 40 for a sufficient duration related to the speed of rotation ofthe platform 19to enable inkto bedischar- gedfromthe print head 50 so asto markthe goblet 100 with afirst ring; stopthedischargeofinkfrom the print head 50 and move the print head 50 to the next desired level relative to the base 40 whereupon the discharge ofinkwould bestarted again, andthen repeat these steps again for the third ring. Finallythe print head 50 would be returned to the start level whilethe carousel 12 rotates 90" to bring the cor responding goblet of the next set into position for marking.

If it is desired to additionally markthegloblet 100 with vertical lines at equidistant spaced apart inter vals thefollowing procedure may be followed.

A disc 60 (Figure 6) is contained in the housing 11.

The disc 60, which is preferably metal, has a shaftengaging hole 61 for rotating the disc 60, and a plurality of relatively small holes 62 located in a specific pattern therein. The concentric lines 63-68 shown in the drawing are presentonlyforease ofunderstand- ing the function ofthe disc 60 and are absentfrom the actual disc 60.

The disc 60 preferably has a reflective surface. It will be seen from Figure 6 ofthe drawingsthatthe concentric ring 63 has three holes thereon, the ring 64 has four holes, and soon up to eight holesforthe ring 68. The disc 60 is rotated, preferably underthe control of the microcomputer referrerd to above, at a speed related to the speed of rotation oftheturntable 19.

A beam of light, preferably a laser beam, is shone normally onto the reflective surface of the disc 60.

The laser beam is mounted on a tracking device in the housing 11 so that it is movable radially relative tothe disc60. Thus,the laser beam may be positioned so asto shine,forexample on the ring 64.

A laser beam detector is also mounted on the tracking device so that light which is reflected from the disc 60 is transmitted into the detector. As long as the detector receives reflected light, a signal is sent to the microcomputer which, in turn, stops the discharge of inkfrom the print head 50 during vertical movement of the print head 50.

If however, light is not reflected from the disc 60, and this wi l l occu r when the beam passes through one ofthe holes 61 in the ring 64, a signal is sentto the microcomputer which in turn activates the print head 50 to discharge ink onto the goblet 100. The dur ation of discharge ofthe inkwiil last onlyforas long as light is not reflected from the disc 60, which duration, it will be appreciated, is relatively short.Thus only a few drops of inkwill be discharged from the print head 50 to leave a dot mark on the goblet 100 at that location.Asthere arefourholes in the ring 64 and as the speed of rotation ofthe goblet 100 is related to the speed of rotation ofthe disc 60, vertical movementofthe print head 50will result in fourvertical lines being marked on the goblet 100 equidistant from each other. The discharge ofinkfromthe print head 50 for marking rings on the goblet 100 is independent ofthe laser beam signal to the computer, and it will be appreciated that it is not necessaryto stopthe discharge ofinkfrom the print head 50when the print head is stationary as the discharge of ink from the print head 50forthe purpose of marking rings on the goblet 100 will be coincident with the marking ofthegoblet l00forthepurposeofavertical line.

If itis desired to markthe goblet 100 with sixvertical lines equidistant from each other, then the laser beam is tracked radially outwards relative to the disc 60 so that it is positioned above the concentric ring 66.

Itis preferred that the inkwhich is discharged onto the goblet 100 should dry immediately. It has been foundthatinksold byAmericanTechnologiesLimited underthe code "DA 10 Black Ink" is suitablefor this purpose.

In order to warn the operator of the apparatus 10 that the carousel 12 is about to move, it is desirable that a strobe light 70 be provided which, underthe control of the microcomputer, will flash just priorto the movement of the carousel.

Sometimes, during the course of manual inspection ofthe goblet prior to marking it by means ofthe apparatus 10 a flaw is detected in the glass which, if the glass was cut at the location of the flaw, would elimitatetheflawthereform.

Thus, at the manual inspection stage, it is preferable to manually mark a detected flaw with a suitable marker. When this marked goblet arrives at the centering station 13, a detector 80 may be used to detect such a mark. Each of the turntables 19-22 has a respective detector 80 associated therewith at the centering station 13. When the goblet arrives at the centering station 13,the detector 80 is activated and the turntable 19 is rotated to rotate the goblet in front of the detector 80. The detector 80 may be of a well known type which has the ability to sense the presence of a mark on the goblet. Underthe direction of the microcomputer, the orientation of the flawed goblet may be arranged atthe centering station 13 such that when the flawed goblet arrives at the marking station 14, ink is discharged so as to coincide with the manually placed mark on the flawed goblet which, later, atthecutting stage, has the flaw removed therefrom to leave an unblemished cut glass goblet.

This invention is not limited by orto the specific embodiment described which can undergo considerable variation without departing from the scope of the invention.

Claims (11)

1. An apparatus for marking the surface of an article, comprising a marking station, means for rotating the article at the marking station, inkjet printing means at the marking station for discharging ink onto the article in a direction transverse to the axis of rotation ofthe article, and means for moving the printing means in a direction substantially parallel to the axis of rotation of the article.

2. An apparatus according to claim 1, further comprising an article loading station and conveyor means fortransporting the article to the marking station from the loading station.

3. An apparatus according to claim 2, wherein the means for rotating the article at the marking station comprises a turntable.

4. An apparatus according to claim 3, wherein the turntable is carried by the conveyor means, the art- icle being loaded on the turntable at the loading station.

5. An apparatus according to claim 4,furtherincluding a centering station intermediate the loading station and the marking station, the centering station comprising means to centre an article relative to the axis of rotation of the turntable while the conveyor means is temporarily halted.

6. An apparatus according to claim 5, wherein the centering means comprises a plurality of members symmetricaily disposed and movable radially relat ive to the axis of rotation ofthe turntable for engaging the outer surface ofthe article.

7. An apparatus according to claim 4,5 or 6, further including vacuum means for maintaining the article on the turntable during movement ofthe article by the conveyor means to the marking station and during rotation ofthe article ofthe marking station.

8. An apparatus according to claim 7,whereinthe vacuum means comprises a pipe extending to the centre ofthe turntable from the opposite side to that which supportsthe article, and meansforsupplying vacuum to the pipe.

9. An apparatus according to any one of claims 2 to 8, wherein the conveyor means comprises a carousel.

10. An apparatus according to any preceding claim, wherein the apparatus is adapted to ac commodate a plurality of articles for simultaneous processing at the or each station.

11. An apparatus, substantially as described herein with reference to the accompanying drawings