Patent Publication Number: US-3878782-A

Title: Imprinting machine and method of operation

Description:
1451 Apr. 22, 1975 United States Patent 1191 Coffelt [5 IMPRINTING MACHINE AND METHOD OF 3.537.393 11/1970 101/235 OPERATION FOREIGN PATENTS OR APPLICATIONS Germany 101/244 3 6 9 H 2 6 oo 6 3 t S S k k um 93 m4 fi.m O h S. m pk 6 DH R 0 t. n e V n l. 6  
 Primary E.\&#39;aminerRobert E. Pulfrey Assistant E.\&#39;amt&#39;ner--William Pieprz Agent, or FirmAlbert L. .leffers; Roger M.  
 v. w H 0 t t A 3 7 9 l 3 8 H r n. m A3 0 N .L P F n. FA NH 22 Rickert ABSTRACT An imprinting machine, and method of operation thereo f, in which work members, such as cartons or labels, or the like, which are to be printed are fed L ,1 7 57 433 munm w l. l 4 M B63. 2 M 0 M 7 1 .3 .a W32 5 t 3 4 2 &#34;n U m/ w M m 7 n W J m mfis mSw .l f C lo WM Mk U [F .H H m 5 55 through the machine with the machine having a rotary printing head, preferably heated, and a transfer, or printing, ribbon disposed between the printing head [56] References Cited UNITED STATES and the workpiece. The printing head rotates continu- PATENTS ously and is moved to and from imprinting position by a fluid cylinder. The advancing of the ribbon is synchronized with rotation of the head and takes place only when the printing head moves to printing position, thus conserving the ribbon and causing ribbon advance only when necessary. The ribbon is advanced by means of a stretch belt connected to the print head and the ribbon wind-up spool which is drawn tight to advance the ribbon when the head is moved to the imprinting position.  
 5 Claims, 7 Drawing Figures m.mm m .m unuug &#34;n&#34; L &#34;uv &#34;rh u a m y mm h t a s mw mc n mmn ommmm mulmmoo SBKBSMTRCFCG 92379 2344009 455556666666 999999999999 HHHHHHHHHHH 52 73 2220 IMPRINTING MACHINE AND METHOD OF OPERATION The present invention relates to an imprinting machine and to a method of operation thereof and is particularly concerned with a high speed hot imprinting machine.  
  Imprinting machines for imprinting labels, boxes, cartons and the like, are known but, heretofore. have presented certain problems. Many of the machines are of the start and stop type with the printing head moving intermittently and some are the type in which the printing head reciprocates to and from printing position. while in others the feed of the ribbon which carries the imprinting material is not synchronized with the printing operation.  
  With the foregoing in mind, a primary objective of the present invention is the provision of an imprinting machine, and a method of operation thereof, in which the drawbacks referred to above are eliminated.  
  Another object of the present invention is the provision of an imprinting machine of simplified construction which will operate extremely rapidly.  
  Still a further object is the provision of an imprinting machine that carries out an imprinting operation only when a workpiece, such as a carton, label, or the like is advanced into the machine.  
  Still another object of the present invention is the provision of an imprinting machine having a rotary printing head and wherein the ribbon feed takes place only while the printing head is rotating and imprinting simultaneously.  
 BRIEF SUMMARY OF THE INVENTION According to the present invention. a drive shaft is mounted in the frame of the machine and is continuously driven in rotation. Extending in the same plane as the drive shaft, and positioned above the drive shaft, is a printing shaft supported in a bracket which is pivotally attached at one end to the frame of the machine so that the printing shaft can be tilted relative to the drive shaft in the plane of the shafts. At the one end the printing shaft carries a gear which meshes with another gear on the drive shaft and these gears remain in mesh in all tilted positions of the printing shaft. At the end of the printing shaft opposite the aforementioned gears, is a printing head which has the type face, or the like, thereon which is to be imprinted. The tilting of the printing shaft is accomplished by an air cylinder connected to the support frame of the printing shaft which can be reversibly energized for tilting the printing shaft up and down in the machine.  
  The frame of the machine carries a ribbon supply reel and a ribbon take-up reel and the ribbon is guided therebetween and across beneath the printing head and in spaced relation thereto when the printing head is in retracted position. Directly opposed to the printing head is a pressure roller and, when the printing head is advanced downwardly, the head engages the back of the ribbon and presses the ribbon against a workpiece passing therethrough, with the workpiece being, in turn, pressed against the pressure roller. The printing head is preferably heated and this causes material carried by the ribbon on the side facing the workpiece to be transferred thereto. The printing shaft and printing head rotate continuously but up and down movement of the printing shaft and printing head is under the control of a detector which detects the movement of a workpiece into working position.  
  The foregoing objects as well as still other objects and advantages of the present invention will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:  
  FIG. I is a perspective view looking in at a printing machine according to the present invention from the front.  
  FIG. 2 is a perspective view similar to FIG. I, but looking in at the machine from the back.  
  FIG. 3 is a side view of the machine. looking in from the right side of FIG. I and the left side of FIG. 2, and partly broken away.  
  FIG. 4 is a somewhat schematic front view of the machine.  
  FIG. 5 is a sectional view indicated substantially by line 5-5 on FIG. 3.  
  FIG. 6 is a schematic view showing the printing head and the heaters therefor and the thermostat mounted on the side of the printing head which controls the supplyof energy to the heaters.  
  FIG. 7 is a schematic representation of a control circuit for the imprinter according to the present invention.  
 DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings somewhat more in detail, and with particular reference to FIGS. 1 to 5, the printer comprises a frame 10 adapted for supporting the unit when used by itself and also for supporting the unit when the unit is placed in line to cooperate with other machinery.  
  A drive shaft 12 is rotatably mounted in frame 10 and is adapted for being connected to a source of driving power, such as a motor, or such as a drive member of a machine with which the imprinter is placed in line. Drive shaft 12 carries a drive gear 14 and this gear meshes continuously with another gear l6,&#39;which is mounted on a printing shaft 18. Printing shaft 18 is supported by a bracket structure 20, which at the end thereof adjacent gears 14 and 16 is pivotally connected to main frame 10 as by pivot means 22.  
  At the end of shaft 18 opposite gear 16 there is a printing head 24&#39; which, as will best be seen in FIG. 1, is somewhat flattened on the sides and on one face carries type or the like, generally indicated at 26, and which is the material, or legend, or symbol, or the like, which is to be imprinted on a work member.  
  The bracket 20, intermediate the ends thereof, is pivoted as at 28 to a yoke 30 extending upwardly to above bracket 20 and connected to the ram 32 of a double acting air motor having a cylinder 34 to the ends of which are connected air conduits 36 and 38.  
  Also carried by the main frame, as on a spindle 40, as a ribbon supply reel 42 about which a ribbon 44 is wound. Also carried by main frame 10 is another spindle 48 on which a ribbon take-up reel 50 is rotatably mounted.  
  The ribbon passes downwardly from supply reel 42 and over a first guide roller 52 and then extends horizontally across beneath printing head 24 and about a second guide roller 54 and then vertically upwardly to take-up reel 50. Wire ribbon guides 56 and 58 assist in guiding the ribbon to and from the guide rollers 52 and 54. The ribbon 44 is in spaced reiation to the printing head 24 when the printing head is in an upper, retracted position but passes closely above a pressure roller 60 which is in the same vertical plane as printing head 24.  
 - As will best be seen in FIG. 3, pressure roller 60 is mounted on a bracket 62 that can be vertically adjusted in the machine as by the threaded adjusting screw 64 and clamped in adjusted position as by clamp screw means 66. By providing for the adjustability of pressure roller 60 various thicknesses of workpieces can readily be accommodated for.  
  FIG. 3 will also show an adjustable stop screw 68 which is provided to limit downward movement of printing head 24 when motor 34 is energized to thrust yoke 30 in the downward direction.  
  The take up spindle 50 is provided with a drive pulley 70 and mounted on shaft 18 behind printing head 24 is a pulley 72. There is entrained about these two pulleys a resilient drive belt 74 which may be of rubber-like material, or which may be in the form of a coil spring. The length of belt 74 is so selected that when the printing head 24 is retracted to its upper position as illustrated in FIG. 3, the drive belt does not drive ribbon take-up reel 50. However, when the printing head is moved downwardly into printing position by the fluid motor, the belt 74 is drawn taut into driving relation with pulleys 72 and 70 and does cause rotation of ribbon take-up reel 50. By this arrangement, the ribbon take-up reel is only driven when the printing head is lowered into printing position so that the use of ribbon is quite economical with the ribbon only advancing when it is necessary during a printing operation.  
  Since the machine is adapted to operate at relatively high speed, it is of advantage to prevent the supply reel 42 from turning too much while it is also desirable to retain the ribbon taut between the reels 42 and 50. To this end, an adjustable drive brake arrangement 76 is associated with reel 42 and supplies sufficient drag thereto to permit feeding of the ribbon from reel 42, while preventing reel 42 from running ahead at any time.  
  In a machine of the nature disclosed herein it is advisable for the printing material, which is on the side of ribbon 44 which faces away from the printing head, to he heat sensitive and to this end the printing head 24, as shown in FIG. 6, comprises heater means 78, preferably electrically operable, and connected in circuit with a thermostatic element 80 and also carried by the printing head. In this manner, the temperature of the printing head can be closely controlled.  
  As will best be seen in FIG. 3, the connection tothe thermostatic element and heating means, is accomplished by way of the double slip ring arrangement 82 mounted on shaft 18 and which is engaged by brushes, one of which is indicated at 84 in FIG. 3. The wires leading from the slip rings to the thermostatic element and heating means can be taken along the shaft in a groove or inside the shaft and then connected to the heating means and thermostatic element by wires.  
  Also carried on drive shaft 12 is a cam 90 which is employed in connection with controlling the machine as shown in FIG. 7. Cam 90 will be seen to control a limit switch LS1 which closes on a contact 92 when cam-90 is in one position and on a contact 94 when cam 90iis in another position.  
  Contact 94 is connected through a first solenoid S1 with power line Ll, while contact 94 is connected through a sccond solenoid S2 with power line L1. The solenoids pertain to a self-centering air valve 96 which is connected via the aforementioned conduits 36 and 38 with the opposite ends of air cylinder 34 for causing reciprocation of ram 32 which is connected to the aforementioned yoke 30.  
  The blade of limit switch LS1 is connected with a contact 98 pertaining to a limit switch LS2, the blade of which is connected to power line L2 and which blade normally rests on a contact 100. When a work member, indicated at 102, approaches working, or printing, position, the blade of limit switch LS2 will be moved into engagement with contact 98 and this will supply energy to limit switch LS1 which will move between contacts 92 and 94 in conformity with the rotated position of cam and thereby controlling the up and down movement of the printing head during continued rotation thereof.  
  It will be apparent that as soon as a workpiece moves out of the range of switch LS2, the up and down movement of the printing head will be interrupted. Normally, for a single workpiece there will be a single downward movement of the printing head, although it is conceivable for a long ribbon-like workpiece consisting, perhaps, of interconnected labels, that the up and down movement of the printing head would be substantially continuous. In any case, the cam 90 is so oriented on the printing shaft 18 relative to the printing head that the up and down movement of the printing head takes place in the proper timed relationship to the operation of the remainder of the machine and to the movement of workpieces in the space between printing head 24 and pressure roller 60.  
  It will be evident that the machine of the present invention is capable of operating at high speed and that it can be adjusted to accept relatively thick work members and relatively thin work members; that it can be operated independantly; or it can be seen in line with another machine.  
 It will be evident that the adjustments impart flexibility to the machine and permit the aforementioned high speed operation thereof in a reliable manner.  
  It might be noted that the precise ribbon position laterally in the machine can be accomplished by adjustment of the wire ribbon guides 56 and 58, as by availing of screws 104 by means of which the ribbon guides can be locked in adjusted positions.  
  The machine according to the present invention is relatively inexpensive to construct, and, as mentioned, is quite reliable in operation and will operate reliably at high speed. The machine is particularly conserving of ribbon because the ribbon only moves while the printing head is in printing position and does not rotate when the printing head is in retracted position.  
  Modifications may be made within the scope of the appended claims.  
 What is claimed is:  
  1. In an imprinter; a frame, a rotary printing head and a pressure member in radially opposed relation in said frame, means in said frame for advancing said printing head toward said pressure member into printing position and for retracting said printing head away from said pressure member into idle position, ribbon supply means operable to supply a ribbon into the space between said printing head and pressure member which will imprint on a workpiece disposed between the ribbon and said pressure member when said printing head is advanced into printing position, feed means for feeding said ribbon in the circumferential direction of said printing head when the printing head is advanced into printing position, said ribbon supply means includes means for rotatably supporting a ribbon supply reel on said frame on one side of said pressure member, said ribbon feed means being disposed in said frame on the other side of said pressure member, a ribbon wound up on the supply reel and leading therefrom to said feed means, first means for driving said print head in rotation continuously, and second means for driving said feed means only while said printing head is advanced into printing position, and a bracket, a printing shaft journaled in said bracket and having said printing head mounted on one end thereof, pivot means pivotally connecting the end of said bracket opposite the print head to said frame and said means for advancing and retracting said printing head comprising a reversible actuator connected between said frame and an intermediate point of said bracket, said feed means including a take up reel rotatable in said frame and to which said ribbon is connected, a pulley on said printing shaft, a pulley connected to said take up reel, and a stretch belt entrained about said pulleys, movement of said printing head into printing position drawing said belt tight to cause driving of said take up reel.  
  2. An imprinter according to claim 1 in which said ribbon supply means comprises a supply reel rotatable in said frame and from which said ribbon leads, and a drag brake connected to said supply reel.  
  3. An imprinter according to claim 1 in which said reversible actuator includes a double acting fluid motor having a reciprocable ram, and a yoke connected to said ram and pivotally connected between said frame ing in unison with said printing head and operable to&#39; actuate said switch means to cause said printing head to advance during one part of a revolution thereof and to retract during the remaining part of a revolution thereof.  
  5. In an imprinter; a frame, a rotary printing head and a pressure member in radially opposed relation in said frame, means in said frame for advancing said printing head toward said pressure member into printing position and for retracting said printing head away from said pressure member into idle position, ribbon supply means operable to supply a ribbon into the space between said printing head and pressure member which will imprint on a workpiece disposed between the ribbon and said pressure member when said printing head is advanced into printing position, feed means for feeding said ribbon in the circumferential direction of said printing head when the printing head is advanced into printing position, said ribbon supply means includes means for rotatably supporting a ribbon supply reel on said frame on one side of said pressure member, said ribbon feed means being disposed in said frame on the other side of said pressure member, a ribbon wound up on the supply reel and leading therefrom to said feed means, first means for driving said print head in rotation continuously, and second means for driving said feed means only while said printing head is advanced into printing position, and a bracket, a printing shaft journaled in said bracket and having said printing head mounted on one end thereof, pivot means pivotally connecting the end of said bracket opposite the print head to said frame and said means for advancing and retracting said printing head comprising a reversible actuator connected between said frame and an intermediate point of said bracket, said ribbon supply means including a supply reel rotatable in said frame on one side of said pressure member, said feed means including a take up reel rotatable in the frame on the other side of said pressure member, ribbon guide means between said reels and said pressure member guiding the ribbon in a horizontal path which is spaced from said printing head when the latter is in retracted position, a pulley connected to said take up reel, a pulley on said printing shaft, and a stretch belt entrained about said pulleys which tightens up when said printing head is advanced to printing position.