GB2187583A - Hand-held labelling machine - Google Patents

Abstract

A hand-held labeller, with a thermo graphic print head, senses the position of the web to control the position of the imprints on the web. A circular indexing member having a plurality of position defining indices provides indications representative of the position of the web. Operation of the printing head and data transfer to and from a semiconductor memory are both automatically stopped if the supply voltage drops below a predetermined level. <IMAGE>

Description

GB2187583A 1 SPECIFICATION optical sensor that senses the position of in

dices on the timing disc, and provides a signal Hand-held labeling machine representative of web position. The timing disc includes at least one and preferably more This invention relates generally to printing de- 70 home position indices that defines the bound vices, and more particularly to hand-held label- ary between two successive labels, one or ers utilizing circuitry accurately to determine more position determining indices and a warn the position of the printing web, and to con- ing index disposed adjacent to the label trol the operation of the printing head, preferaboundary defining index that informs the sys bly a thermographic printing head, in response 75 tem that the label boundary is approaching.

to position signals to thereby accurately posi- The indices are sensed by the sensor and tion the imprints on the web. used to provide position indicative signals to Hand-held labelers utilizing thermographic the system for controlling the operation of the printing devices are known. Examples of such printing head.

hand-held labelers are illustrated in our United 80 Because of the precise positioning informa States patents Nos. 4,264,396 and tion provided by the timing disc, manufactur 4,407,692, and United States patent applica- ing tolerances become significant Conse tion Serial No. 485,012 filed April 14, 1953 quently, there is preferably provided an adjust (see British Patent Application No. 2,138,190 ing mechanism for adjusting the angular posi- published October 17, 1984). 85 tion of the timing disc relative to the feed While the devices disclosed in the above- mechanism. This is accomplished by permit- described references do provide a way to ting the disc to be positioned on the shaft make imprints on a thermosensitive web, they driving the disc at a plurality of discrete angu are capable of improvement in certain re- lar positions, each associated with one of the spects. For example, when printing with a 90 home position indices. Such positioning can thermal printing device, particularly with a high be accomplished by providing a plurality of density printing device such as one of the unequally spaced key slots or the like in the devices illustrated in the aforementioned U.S. disc, by providing a single key or spline on Patent No. 4,407,692 and British Patent Ap- the shaft for engaging one of the key slots.

plication No. 2,138,190, it is necessary accu- 95 By making the angular position of each key rately to control the timing of the energization slot slightly different relative o its associated of the various printing elements as a function home position index and positioning indices, of the position of the web. For example, in an adjustment can be readily achieved by po such a system, the web is continuously fed, sitioning the appropriate key slot over the key and the appropriate printing elements must be 100 or spline to provide the desired offset be- energized at the precise time that the portion tween the shaft and the disc.

of the web on which the imprinting is desired The invention will now be described in more is positioned adjacent the printing head. The detail, by way of example, with reference to difficulty of the problem is further com- the drawings, in which:

pounded by the fact that each of the printing 105 FIG. 1 is a perspective view of a hand-held elements has a length and a width of only a labeler constructed in accordance with the few mils. As a result, the position of the web principles of the present invention; or the timing of the energization of the print- FIG. 2 is a system block diagram of the ing elements, must be precisely controlled to logic circuitry controlling the thermographic avoid printing gaps and changes in print den- 110 printing apparatus according to the invention; sity, as well as changes in character shape, FIG. 3 is a plan view of a thermographic particularly when the speed of the web varies print head usable with the printing apparatus as it passes the printing head, as for example, according to the present invention; in the case of a labeler having a hand ad- FIG. 4 is a block diagram illustrating one vanced web. 115 embodiment of the print head driving circuitry; The invention in its various aspects is de- FIG. 5 is a block diagram of an alternative fined in the appended claims to which refer- embodiment of the print head driving circuitry; ence should now be made. FIG. 6 is a block diagram illustrating the po In a preferred embodiment of the invention, sition sensing and printer control circuitry ac there is provided a hand-held labeler utilizing a 120 cording to the invention; microprocessor-based control system that FIG. 7 is a detailed illustration of the timing senses the position of the web and controls disc illustrated in FIG. 6; the operation of the printing head in accorFIG. 8 is a block diagram of the motor dance with the position of the web in order to speed control portion of the control circuitry assure that any imprints are accurately posi- 125 of the invention; tioned on the web, and on any labels cut FIG. 9 is a timing diagram illustrating the from the web. The system employs a precise operation of the motor speed control circuit timing disc that is coupled to the label ad- according to the invention; vancing mechanism. The timing disc coop- FIG. 10 is a logical flow diagram illustrating erates with a sensor, such as, for example, an 130 the operation of the control circuit according 2 GB2187583A 2 to the invention; and terface adapter 40 are a trigger switch 44 FIGS. 11 and 12 illustrate circuitry for pro- that:is controlled by the trigger 28, and a tecting the data stored in the labeler in the control circuit 46 that operates a motor 48 event of a discharged battery and when the that drives a web advancing wheel 49. A de battery is removed. 70 tector 50 senses a mark or index on the web advancing wheel 49, or preferably on a sepa DETAILED DESCRIPTION OF THE PREFERRED rate timing disc 51. The control circuit 46

EMBODIMENT responds to data received from the micropro Referring now to the drawing, with particular cessor 42 and controls the operation of the attention to FIG. 1, there is shown a thermo- 75 web advancing motor 48, which may prefera graphic microprocessor-controlled hand-held la- bly be a D.C. motor. An audible alarm 52 is beler according to the invention, generally also connected to the peripheral interface designated by the reference numeral 10. The adapter 40, and is useful for indicating to the labeler 10 includes a housing 12 that supports operator that a problem or potential problem a roll 14 of adhesive backed labels 16 that 80 exits. For example, the audible alarm 52 may are supported on a backing web 18. A key- be used to indicate a discharged or faulty bat board 20 is disposed on the housing 12 and tery, a faulty print head, that the labeler is out contains a plurality of individually operable key of labels, a jam, or may simply be used to switches 22 for entering data into the labeler. indicate that data entered into the device has A display 24, which may be a liquid crystal or 85 been received. In the latter case, the audible light emitting diode display, is also disposed alarm 52, can be used to provide an audible on the housing to permit the entered data and indication each time one of the key switches microprocessor-generated prompting instruc22 on the keyboard 20 is depressed.

tions to be viewed by the operator. A battery The display 24 is coupled to the micropro pack, which may be contained in a removable 90 cessor 42 via a display driver 54. The display battery pack-handle unit 25 containing a bat- 24 is used to display data being inputted into tery 26 having an internal resistance 27, pro- the microprocessor as well as other messages vides electrical power for the labeler 10. A such, for example, prompting and diagnostic trigger 28 is provided to initiate the label messages generated by the microprocessor. A printing operation, and a label applying roller 95 read-only memory (ROM) 56 is provided for is used to apply pressure to the adhesive storing permanent Data, such as the program backed label 16 when the label 16 is being defining operation of the device. The read-only applied to an article of merchandise. A label memory 56 may either be permanently in stripper (not shown) is contained within the stalled in the labeler 10, or may be removably housing 12 to separate the labels 16 from the 100 installed in a socket or the like to permit the backing strip 18. A plurality of guide rollers font and/or format to be changed by changing are provided to guide the separated labels 16 the memory 56. In addition, a randomaccess to the forward portion of the housing beneath memory (RAM) 58, usable for storing short the label applying roller 30, and to guide the term data, such as data entered via the key backing strip to the rear of the housing be- 105 board 20, is provided, as is a non-volatile ran neath the roll 14. dom-access memory (NVRAM) 60, suitable for As previously stated, the labeler according storing data such as format data. The inpu to the invention is quite versatile and is t/output connector 32 provides communi capable of printing alphanumerics, as well as cations between the device and an external bar codes including the Universal Product 110 computer. Printing is accomplished by a print Code (UPC) and the European Article Number head assembly 64 that contains a print head (EAN). The type of format, whether alphanu- 66 and print head driver 68 coupled to the meric or bar code, is readily selected by en- peripheral interface adapter 40. An analog-to tering the appropriate format and fonts defin- digital converter 70 coupled to the peripheral ing data via the keyboard 20. The data to be 115 interface adapter 40 senses the battery vol printed, for example, price, product defining tage or the voltage applied to the print head data and other information about the product assembly 64, and provides a digital indication such as the size, color, etc. is also entered via of that voltage to the peripheral interface the keyboard 20. In addition, the number of adapter 40 so that the microprocessor may labels to be printed may be entered. Also, a 120 adjust the time that the print head is energized data input/output connector 32, may be pro- to compensate for variations in battery or vided on the housing to permit data to be print head voltage.

entered into the labeler by an external source, One example of the print head assembly 64 such as, a remotely-located computer, and to is illustrated in simplified form in FIG. 3. In the permit the battery 26 to be charged. 125 illustrated embodiment, the print head as Referring to FIG. 2, the keyboard 20 is sembly 64 contains the print head driver 68 coupled to a peripheral interface adapter (PIA) and the print head 66 disposed on a thin film which provides an interface between varisubstrate. The print head has a single line of ous input and output devices and a micropro- print elements disposed transverse to the di cessor 42. Also coupled to the peripheral in- 130 rection of travel of the web 18, and is parti- 3 GB2187583A 3 cularly suitable for use in a hand-held labeler one of the strobe signals in order to be fully because of the high density of the print ele- enabled, only one-fourth of the gates 84 are ments that make up the print head 66, parti- enabled at any given time. Thus, the data cularly if both alphanumerics and bar codes from the data register 88 is applied to the are to be printed. One print head assembly 70 heater driver transistors 82 in four steps, so particularly usable as the print head assembly that no more than onefourth of the transis 66 employs 224 printing elements that are tors 82 may be energized at a given time.

each 10 mils long and 4.4 mils wide, and An alternative embodiment of the print head spaced on 5.2 mil centers. Such a configura- driving mechanism is illustrated in FIG. 5. The tion permits a virtually continuous line to be 75 embodiment illustrated in FIG. 5 is similar to printed. the one illustrated in FIG. 4, except that the Each of the printing elements constitutes a input register 86 is broken up into a plurality resistive heating element 80 (FIG. 4) that is of smaller registers, for example, seven 32 individually energizable by the print head driver stage shift registers 86' in the illustrated em circuitry 68 which contains a heater driver 80 bodiment. Such an arrangement has the ad transistor 82 for each of the printing elements vantage that it permits data to be entered 80. A gate 84 controls each of the heater more rapidly into the system, thereby permit driver transistors 82, and an input register 86 ting a faster printing speed. This occurs be and a data register 88 control the operation of cause each of the seven shift registers 86' the gates 84. Thus, if a 224-element head is 85 can be fed in parallel from said seven separate used as the print head 66, 224 driver transis- data lines 90'. Consequently, the data need be tors 82 and 224 gates 84 must be provided, shifted only 32 times to load the registers and the input register 86 and the data register 86% as opposed to the 224 shifts required to 88 must each have at least 224 stages. load the input register 86. However, when The input register 86 receives data serially 90 loading the shift registers 86' the 224 bits from a data input line 90 under the control of defining each line cannot be fed serially into clock signals applied to a clock line 92. When the shift registers 86% but the bits must be the input register 86 is full, the data is trans- grouped so that they may be applied to the ferred in parallel to the data register 88 under appropriate registers. This is accomplished by the control of a latch signal applied to the 95 taking every 32nd bit from the data defining a data register 88 by a line 94. The input regis- line, and applying it to the appropriate one of ter 86 is then reset by a reset pulse applied the shift registers 86'. For example, if 224 to the reset line 96, and new data is supplied bits are used to define a line, the 32nd, 64th, to the input register. 96th, 128th, 160th, 192nd and 224th bits Because the resistive heating elements 80 100 are selected and applied to seven stages of a draw a substantial amount of current, for buffer 108 (FIG. 5). These bits are then ap example, approximately 50 milliamps per ele- plied in parallel to the shift registers 86'. Next, ment, and because of the extreme density of the 31st, 63rd, 95th, 127th, 159th, 191st the elements, for example, approximately 200 and 223rd bits are applied to the buffer 108 elements per inch, the current drain on the 105 and shifted to the registers 86'. The process battery 26 would be excessive if all of the is repeated until the first, 33rd, 65th, 97th, elements 80 were turned on simultaneously. 129th, 161st and 193rd bits are loaded into For this reason, the heater driver transistors the buffer 108 and supplied to the registers 82 are strobed by the gates 84 so that no 86'. At this point, the seven registers 86' more than one-fourth of the heater drivers 82 110 contain the bits 132, 33-64, 65-96, 97-128, may be energized at any one time. 129-160, 161-192 and 193-224. Since this In the embodiment illustrated in FIG. 4, the data completely defines a line, the data from strobing is accomplished by utilizing three in- the registers 86' can be transferred to a data put ANO gates as the gates 84, and by en- register, such as the data register 88 (FIG. 4), abling the gates 84 in blocks. This is accom- 115 or to a plurality of individual data registers 88' plished by providing two block enable signals (FIG. 5). The output of the data register 88' BE1 and BE2 on lines 100 and 102, respec- can be applied to a plurality of threeinput AND tively, and strobes ST1 and ST2 on lines 104 gates 84, or to any suitable device for limiting and 106, respectively. Each of the block ena- the number of individual elements that can be ble signals is connected to one-half of the 120 simultaneously energized.

gates 84 so that one-half of the gates 84 are In FIG. 5, the strobe function that limits the enabled when the BE1 signal is high, and the number of elements that can be simultane other half are enabled when the BE2 signal is ously energized is provided by a plurality of high. The ST1 signal is applied to one-half of circuits 83. Each of the circuits 83 contains the gates 84 receiving the BE 1 signal and to 125 32 two-input ANO gates and appropriate driv one-half of the gates 84 receiving the BE2 ing circuitry for driving the print head 66.

signal. Similarly, the ST2 signal is applied to Such a system is somewhat simpler than the the gates 84 not receiving the ST1 signal. system illustrated in FIG. 4 because only two Thus, since it is necessary for each gate to input AND gates, rather than three-input AND receive one of the block enable signals and 130 gates, are required. By providing three strobe 4 GB2187583A 4 signals S1, S2 and S3, the number of printing inches in diameter, and because of the precise elements that can be simulataneously ener- tolerances required, the use of electro-deposi gized is restricted to approximately one-third ted nickel provides a convenient way to fabri of the total number of print elements. cate the disc. The thickness of the disc 51 is In the embodiment illustrated in FIG. 5, the 70 nominally 3 mils, but may vary from 2 mils to strobe signal S1 is applied to the first two 4 mils.

and the last one of the circuits 83. The strobe As is illustrated in FIG. 6, the disc 51 is signal S2 is applied to the third and fourth mounted on the same shaft (shaft 141) as is ones of the circuits 83, and the strobe signal the web advancing wheel 49 and rotates S3 is applied to the fifth and sixth ones of the 75 therewith to form a shaft encoder. In the illuscircuits 83. Consequently, no more than two trated embodiment, the wheel 49 rotates one out of seven printing elements may be simul- third of a revolution each time a complete la taneously energized when either the strobe bel is fed. Three home position indices in the signal S2 or the strobe signal S3 is present. form of three apertures 142, 144 and 146 are Theoretically, as many as three out of seven 80 provided in the disc 51. In the illustrated em elements may be energized when the strobe bodiment, three home position indices are signal S1 is present, but in practice, the line provided because the disc 51 rotates one of print is seldom as wide as the width of the third of a revolution each time a label is fed; print head 66, and consequently, it is unlikely however, it should be understood that if the that more than one-half of the total elements 85 advancing mechanism were modified such that in the first and last ones of the circuits 83 the disc 51 rotated at a different rate, the would be energized. number of home position indices would have The control circuit 46 (FIG. 6) includes a to be changed accordingly. For example, if the control processor 130 that includes a read- disc 51 rotated one fourth of a revolution only memory (ROM) 132 that may be located 90 each time a label was fed, a disc with four either on the same integrated circuit as the home position indices would be used.

control processor 130 or in a separate pack- Following each of the apertures 142, 144 age. The various components required to carry and 146 is a plurality of position defining in out the print control function are not shown in dices in the form of a plurality of apertures or FIG. 6 for purposes of clarity; however, it 95 slots 148, 150 and 152, respectively (FIG. 7), should be understood that the microprocessor which accurately define the position of the la 42 of FIG. 6 must be coupled to components bel with respect to the printing head. Al that are the same or analogous to the compo- though the position defining indices 148, 150 nents shown in FIG. 2 to provide the printing and 152 can be referred to as either apertures function. The control processor 130 controls a 100 or slots, or by other terminology they will be motor drive/brake circuit 134 that selectively referred to as slots in the following descrip applies energizing or dynamic braking currents tion for purposes of clarity in order to better to the motor 48. An analog-to-digital conver- distinguish them from the home position aper ter 136 measures the back EMF of the motor tures 142, 144 and 146. A warning track is 48 when it is coasting, and applies a digital 105 provided ahead of each of the home position representation of the back EMF to the control indices in the form of three widened areas processor 130 in order to provide an indica- 154, 156 and 158.

tion of the speed of the motor 48 to the When no labels are being printed, one of control processor 130. The detector 50 in- the home position defining apertures 142, cludes a light source, such as, for example, a 110 144, or 146 is aligned with the sensor 50.

light emitting diode 138 and a light sensitive Each of the apertures 142, 144, and 146 is device such as a photodetector 140 disposed sufficiently wide to permit some backlash in on opposite sides of the timing disc 5 1. The the web and drive train to occur without caus detector 50 serves to detect indices formed ing an opaque area of the disc 51 to be de as a series of light contrasting marks such as 115 tected by the sensor 50. This prevents the opaque and transparent portions on the disc motor 48 from hunting in an attempt to keep 51. Preferably, the indices are fabricated as a one of the home position apertures aligned series of apertures about the periphery of the with the sensor 50. The size of the apertures disc 51 which are used to indicate to the 142, 144 and 146 is also selected to permit system the position of the disc 5 1, and conany slack in the web 18 to be taken up be sequently, the position of the web 18 as it is fore one of the position defining indices is advanced by the advancing wheel 49. Al- moved into alignment with the detector 50.

though, an optical system is used to detect The width of the position defining slots the position of the disc 51, other systems 148, 150 and 152 and the width of the areas may also be used. 125 between the position defining slots is selected The timing disc 51 is illustrated in greater such that the distance between the detection detail in FIG. 7. The disc illustrated in FIG. 7 of successive edges of the slots 148, 150 is fabricated from an opaque material. Because and 152 corresponds to a web movement of the relatively small size of the disc 5 1, for that is equal to an integral multiple of the example, on the order of approximately 1.25 130length of the print elements 80. For example, GB2187583A 5 when a printing head such as the previously indicates to the microprocessor 42 that the described printing head 66 is used, the dis- motor is up to speed and the web is posi tance between the detection of adjacent tioned to accept printing at the printing posi edges of the slots 148, 150 and 152 corre- tions defined by the selected print format.

sponds to a web travel that is equal to an 70 As the motor 48 continues to rotate, the integral multiple of 10 mils (the length of the transitions between the slots 148 and the print elements 80). In the timing disc 51 illus- opaque areas disposed therebetween are de trated in FIG. 7, the integral multiple has been tected by the photodetector 140, and signals selected to be equal to two, thus providing a representative of the transitions are applied to web travel of 20 mils between the detection 75 the control processor 130. The control pro of successive edges of the slots 148, 150 cessor 130 responds to the transitions and and 152. As a result, the position of the web generates a position pulse signal and applies it 14 is defined in 20 mil increments. to the microprocessor 42 each time a transi The width of each of the warning tracks tion occurs. The position signals are counted defined by the widened areas 154, 156 and 80 by the microprocessor 42 in order to deter 158 must be made wide enough to permit the mine the position of the label with respect to warning tracks to be distinguished from the the print head 66. When the print head 66 is areas between the position defining slots. In positioned over a print area on the label, as the embodiment illustrated in FIG. 7, the width defined, for example, by the print format, the of the areas 154, 156 and 158 is selected to 85 entered data is printed on the labels 16. The be approximately twice as wide as the widths process continues with the microprocessor 42 of the areas separating the slots 148, 150 receiving position pulse signals from the con and 152. This provides a warning track having trol processor 130 until the entered data is a width that corresponds to approximately printed on one or more print areas of the four times the length of the printing elements 90 labels 16.

80, or approximately 40 mils. The width of As the printing process continues, the tim the areas 154, 156 and 158 is selected such ing disc 51 continues to rotate until the warn that the areas 154, 156 and 158 can be ing track defined by the widened area 154 is readily distinguished from the narrower areas detected. The widened area 154 is detected separating the slots 148, 150 and 152, and 95 by the control processor 130 when the length although in the embodiment illustrated in FIG. of time that an opaque area is being detected 7, the widened areas 154, 156 and 158 have by the photodetector 140 exceeds the length been selected to be approximately twice as of time between the transition pulses gener wide as the areas separating the slots 148, ated by the slots 148 by a predetermined 150 and 152, other widths may be used. 100 amount. Once it has been determined that a In operation, when the labeler is not printing warning track such as the area 154 has been a label, one of the home position defining in- detected, the microprocessor is conditioned to dices, for example, the aperture 142 is aligned respond to the next transition by rendering the with the detector 50. When the trigger switch motor drive/brake circuit 134 operative to 44 (or other manually operable switch) is de- 105 brake the motor 48. Thus, when the leading pressed, the microprocessor 42 (FIG. 6) is- edge of the aperture 144 is detected, a brake sues a start motor command to the control signal is applied to the motor drive/brake cir processor 130 which in turn renders the mo- cuit 134 to cause the motor drive/brake cir tor drive/brake circuit 134 operative to ener- cuit 134 to shunt the armature winding of the gize the motor 48. The light-emitting diode 110 motor 48 to thereby dynamically brake the 138 is also enabled. When the motor 48 is motor 48. The motor 48 continues to coast energized, the timing disc 51 is rotated in the for a short distance until the aperture 144 is direction shown by the arrows in FIGS. 6 and aligned with the detector 50, and the printing 7. As the motor rotates, any slack present in process is terminated. If it is desired to print the web 18 and any backlash in any of the 115 another label, the trigger switch 44 is again web advancing mechanism is taken up while a depressed and another label is printed as the portion of the aperture 142 is still aligned disc 51 is advanced until the aperture 146 is with the detector 50. The motor 48 continues aligned with the detector 50.

to rotate until the trailing edge of the aperture Also, although the timing disc 51 is shown 142 is detected by the detector 50. At this 120 in conjunction with a motor driven advancing point, all slack in the system has been taken mechanism, it may also be used in conjunction up and the motor 48 is up to operating with a hand or manually operated advancing speed. mechanism. In such an event, even though the When the trailing edge of the aperture 142 signals provided by the timing disc 51 would is detected by the detector 50, the amplitude 125 not be used to control a motor, the position of the signal applied by the photodetector signals would still be used to indicate to the to the control processor 130 changes. microprocessor when a printable area is be The control processor 130 responds to this neath the print head, and cause printing to be change by issuing a start print command to initiated when such an area ispresent.

the microprocessor 42. The start print signal 130 As previously stated, the timing disc 51 6. GB2187583A 6 provides very accurate information defining the ments of the disc 51 relative to the zero de position of the web. However, in order to gree position may be readily attained. Other make use of the accurate position signals pro- adjustments may be achieved by altering off vided by the timing disc 5 1, it is necessary to sets between the keyways 1, 2 and 3. For compensate for manufacturing tolerances pre- 70example, a 2' adjustment by spacing the sent in the web advancing mechanism and in keyway captioned 3 by 124' from the keyWay the positioning of the print head 66. Conse- captioned 1, and by spacing the keyway cap quently, in accordance with another aspect of tioned 2 by 118' from the keyways captioned the present invention, there is provided a way 1 and 3. In general, any offset may be to alter the angular position of the timing disc 75 achieved by appropriately spacing the key 51 with respect to the angular position of the ways 1 and 3 by the total desired positive web advancing wheel 49. Various other key- and negative offset added to 120'. If equal ing means could be used to affix the disc 51 positive and negative offsets are desired, such to the shaft. For example, a slot could be equal positive and negative offsets may be provided on the shaft, and slot engaging 80 achieved by dividing the remainder of the members could be provided on the disc. Al- 360' are between the keyways captioned 2 ternatively, the shaft could be provided with a and the keyways captioned 1 and 3.

plurality of keys or keyslots, and the disc 51 Although various types of motors, including provided with a single keyslot or slot engag- stepping motors, are usable as the web ad ing member. Other variations could be used. 85 vancing motor 48, it has been found that a In the illustrated embodiment, this is accom- D.C. motor is particularly useful as the web plished by mounting the timing disc 51 on a advancing motor 48, partly because of its keyed shaft and providing a plurality of offset good low speed torque characeristics. How keysiots on the disc 5 1. Each of the offset ever, when a D.C. motor is used, it is neces keyslots is associated with one of the home 90 sary to provide circuitry for controlling the position indices 142, 144 and 146 and is off- speed of the motor shaft. In the present em set therefrom by the amount of adjustment bodiment, the motor speed control is provided required. Thus, any required adjustment may by the control processor 130. As previously be obtained by positioning the appropriate slot discussed, the control processor 130 receives on the key of the shaft. 95 signals representative of the back EMF gener For example, in the timing disc illustrated in ated by the motor 48 when it is coasting, and FIG. 7, three keyways captioned 1, 2 and 3 adjusts the drive signal applied to the motor are shown. The angular' displacement between 48 to thereby maintain the speed of the mo the keyways 1 and 3 is nominally 122', while tor 48 substantially constant.

the angular displacement between the key- 100 Referring to FIG. 8, the motor 48 is driven ways 1 and 2, and 2 and 3 is nominally 119'. by the motor drive/brake circuit 134 which This compares with a 1200 angular displace- includes a transistor drive circuit 170 that ap ment between the leading edges of the aper- plies an energizing potential to the motor 48 tures 142, 144 and 146, and permits a 1' when a run signal is received from the control adjustment of the disc 51 relative to the web 105 processor 130. An interlock circuit prevents advancing wheel 49 and the detector 50. both the run and brake signals from being If for example, the keyway designated by applied to the drive/brake circuit 134 simulta the numeral 1 were keyed to the shaft 141 neously in the event of a microprocessor or by a key 160, the trailing edge of the aperture other malfunction. The motor drive/brake cir 142 will lead the center line of the key 160 110 cuit 134 also includes a dynamic braking cir by approximately 2'. The 2' offset shall be cuit 172 that shunts the armature of the mo called the minus 1' position. If the keyway tor 48 to provide dynamic braking when a captioned by the numeral 3 is keyed to the brake signal is received from the control pro key 160, because the keyways 1 and 3 are cessor 130. A comparator 174 is connected spaced by 122', the trailing edge of the aper- 115 to the motor 48 and serves to compare the ture 144 will lead the center of the key 160 back EMF generated by the motor 48 when it by 4', thus resulting in a positive 2' shift in is coasting with a reference voltage. A sampl the position of the positioning slots with re- ing gate 176 couples the output of the com spect to the minus 1' position. Adding 2' to parator 174 to the control processor 130.

minus 1' results in positive 1', so this posi- 120 The run signal applied to the drive circuit tion can be considered the plus 1' position. If 170 includes a series of pulses which cause the keyway captioned by the numeral 2 is the drive circuit 170 to energize the motor 48 keyed to the key 160, the disc 51 will have at periodic intervals. The back EMF generated been rotated a total of 122' plus 119' or by the motor 48 between drive pulses is sam 241' relative to its position when keyed to 125 pled by the comparator 174 and the sampling keyway number 1, thus resulting in a positive gate 176, which operate as an analog-todigital 1' shift in the position of the positioning slots converter, to indicate to the control processor relative to the minus 1' position. Thus, this 130 whether the back EMF generated by the position becomes the zero degree position, motor 48 is greater than or less than the ref- and positive and negative 1 degree adjust- 130erence voltage applied to the comparator 174.

7 GB 2 187 583A 7 If the back EMF is less than the reference time 5T; however, if the back EMF is higher voltage, the next run pulse is generated by than the reference voltage, no run pulse will the control processor 130 again to energize be generated at time 5T, as is illustrated in the motor 48. If the back EMF generated by FIG. 9. Rather, the back EMF will be sampled the motor 48 is greater than the reference 70 during a subsequent sampling interval 188 voltage, indicating that the speed of the motor prior to the time 6T, and if the back EMF has is excessive, the next run pulse is eliminated, dropped below the reference voltage, another and the motor is allowed to coast. During the run pulse 190 will be generated at the time coasting period the back EMF is measured at 6T. The process will be repeated at periodic periodic intervals until it drops below the ref- 75 intervals with the run pulses being eliminated erence voltage, at which point another run as required to maintain the speed of the mo pulse is generated. The speed of the motor tor 48 substantially constant.

may be adjusted by adjusting the reference Referring now to FIG. 10, when the labeler voltage. is initially energized, the parameters in the mi- The run pulse generation and back EMF 80 croprocessor 42 and the control processor 46 sampling is illustrated in greater detail in FIG. are initialized, and the control processor 46 is 9. Referring to FIG. 9, the back EMF is sam- conditioned to initiate the feeding of the web pled during a first sampling period 179 occur- upon receipt of a start pulse from the micro ring during a portion of the time interval rang- processor 42. Upon receipt of a start pulse, a ing from zero to T. If the back EMF is less 85 clock in the control processor 46 is reset to than the reference a run pulse, as illustrated zero. Subsequently, a separate timer is up by the pulse 180 is generated during the time dated to indicate how many times the control interval between T and 2T. The duration of processor clock has been reset. This provides the pulse 180 is controlled by the clock (not an indication of how long the motor 48 has shown) in the control processor 130, and is 90 been running. If the time exceeds a predeter preferably on the order of 500 microseconds mined limit, the run timer times out, the motor to 1 millisecond. No sample is taken during is stopped and braked, and the control pro the time interval between T and 2T because cessor 46 is conditioned to await the next such a sample would be meaningless because start pulse. A signal may also be sent to the all that would be measured would be the am- 95 audio alarm 52 to indicate a jam. If no time plitude of the pulse 180. out occurs, the detector 50 is sampled to de After the run pulse 180 has been termitermine whether a start print bdge (first opa nated at the time 2T, the drive to the motor que edge after home position aperture, FIG. 7) 48 is also terminated; however, the termina- has been encountered. If the edge has been tion of the drive to the motor 48 results in a 100 detected, a start print pulse is sent to the transient across the armature winding of the microprocessor 42, and the condition of the motor 48. Consequently, the voltage across motor is checked, as is described later. If the the motor 48 is not immediately sampled be- edge passed previously, the timing disc is cause it is not representative of the back EMF checked for a position index. If a position in- being generated by the motor. Instead, the 105 dex is detected, a position pulse is sent to sampling is delayed until a sampling period the microprocessor 42. If no index is de 182 that follows the time 2T by a time inter- tected, the timing disc is checked for the val sufficient to allow the transient to die presence of the warning track (widened opa down. It has been determined that delaying que area, FIG. 7). The widened area can be the sampling period 182 for approximately 110 readily determined by the length of time it is 300 microseconds following the termination of aligned with the sensor 50. When the end of a run pulse allows enough of the transient to the warning track is detected, the motor is die down to permit an accurate reading of the stopped, the brake is turned on for a predet back EMF of the motor 48 to be made; how- ermined time interval, and the control proces- ever, the delay time is dependent on the size 115 sor is conditioned to await the next start mo and inductance of the motor, as well as other tor command.

factors, and other values may be used de- The purpose of the abovedescribed steps pending on the particular components used. is to determine the position of the timing disc, The sampling is done under the control of the and hence the position of the label during the sampling gate 176 which is enabled during 120 printing cycle. In addition to determining the the sampling period 182 and other sampling position of the label, the speed of the motor periods by the microprocessor 130. must be determined. In the logic diagram illus If the back EMF measured during the sampl- trated in FIG. 10, the motor speed check is ing period 182 is too low, another run pulse made subsequent to each position check.

184 is generated during the time interval be- 125 Thus, if the run timer has not timed out, and tween 3T and 4T, and the back EMF is again the end of the warning track has not yet been sampled during a sampling period 186 occur- detected, a motor speed check is made. This ring prior to the time 5T. If the back EMF is accomplished by first checking the motor to during the sampling period 186 is again too see if it is on or off. If the motor is off, the low, another run pulse will be generated at 130 system waits until a sampling period is GB2187583A 8 reached. When the sampling period is applies a signal to the microprocessor 42 and reached, the back EMF is checked to deter- to the control processor 46 in order to put mine motor speed. The result of the check, the processors in a reset condition to prevent indicating whether the motor speed is too fast erratic operation thereof. In addition, the com or too slow, is stored. If the motor is on, no 70 parator 200 applies a disabling signal to the speed check can be made, and the motor is RAM 58 and the NVRAM 60 to prevent data turned off. from being written onto or erased from the After the back EMF hps been checked, or RAMs. A disabling signal is also applied to after the motor has been turned off, the sys- the print head 64 to clamp the print head tem waits for the processor clock to reach 75 driver 68 to thereby prevent energization of time T, that is, the next time at which a run the print head 66. Thus, the RAMs and the pulse can be generated. When the time T is print head are effectively protected from erra reached, the stored result is checked to deter- tic operation of the microprocessors.

mine whether the motor speed was too slow. In order to prevent the loss of data from a If the motor speed had been too slow, the 80 non-volatile read-only memory such as the motor is turned on, the control processor NVRAM 60, a back-up battery, such as, for clock is reset to zero, the run time is updated example, a lithium battery 210 (FIG. 12), is to include the time accumulated by the pro- provided. The use of a lithium battery for such cessor clock during the last cycle, and the a purpose is particularly advantageous because cycle is repeated. If the speed of the motor 85 such batteries have a relatively long shelf life, was not too slow, the motor is not turned on on the order of approximately ten years. How before the processor clock is reset to zero ever, if the lithium battery were used to and the run timer updated. In the event that power the NVRAM for extended periods of the motor was previously on, and no back time, it would become discharged relatively ra EMF check was made and stored, it is as- 90 pidly. Therefore, some means must be pro sumed that the motor speed was not too vided to prevent the back-up battery 210 slow, and the processor clock is reset to zero from discharging prematurely. Thus, when the without turning on the motor. Because the labeler is turned on, the NVRAM 60 is pow motor is now off, a speed check can be read- ered from the main battery, such as the bat ily made during the next cycle. 95 tery 26; however, some provision must be As previously discussed, the labeler accord- provided to power the NVRAM 60 when the ing to the invention is a hand-held labeler that labeler is stored in an off condition for an is powered by a battery. As in the case of all extended period of time.

batterypowered devices, the voltage applied to In the hand-held labeler according to the in the various circuits drops as the battery disvention, the labeler circuits are powered by charges, and may even reach zero when the the battery 26 which is connected to a vol battery is completely discharged or is re- tage regulator 212 via an on- off switch 214 moved. Such voltage variations can cause se- (both not shown in FIG. 2). The regulator 212 rious problems. For example, when the vol- provides a regulated voltage, for example, 5.6 tage applied to a microprocessor drops below 105 volts, to the labeler circuits whenever the on a predetermined level, the operation of the mi- off switch 214 is closed. Under these condi croprocessor becomes erratic. When this oc- tions, the output voltage of the regulator 212 curs, the erratic signals from the microproces- is applied to the NVRAM 60 by means of a sor can alter or erase the data stored in the blocking diode 216, and the NVRAM 60 is various memories. The processor can also 110 powered by the battery 26 via the switch cause damage to the print head, for example, 214, the regulator 212 and the diode 216 by continuously energizing one or more of the whenever the labeler is operating. A diode printing elements. In addition, when a non- 211 isolates the battery 210 from the rest of volatile RAM, such as the NVRAM 60, is the circuitry under these conditions because used, a drop or loss of battery voltage can 115 the voltage applied to the NVRAM 60 is cause the data stored in the NVRAM to be higher than the voltage of the battery 210, lost. and the diode 211 is reverse biased.

Thus, in accordance with another aspect of When the labeler is turned off, the output the present invention, there is provided a cir- voltage of the regulator 212 is zero, and con cuit (FIG. 11) that monitors the voltage pro- 120 sequently, if the labeler is stored for an appre duced by the main battery, such as, the bat- ciable length of time, the back-up battery 210 tery 26, and protects the various memories will eventually discharge if the regulator 212 and the print head in the event of a low bat- were relied on to power the NVRAM 60.

tery condition, and in the event that the bat- Therefore, in accordance with another impor- tery is removed. This is accomplished by a 125 tant aspect of the present invention, there is comparator 200 that compares the voltage at provided an auxiliary circuit that powers the the battery 26 with a low battery voltage ref- NVRAM 60 even when the labeler is off. The erence. In the event that the voltage provided auxiliary circuit includes a Zener diode 218 by the battery 26 drops below the low bat- that is coupled to the battery side of the tery reference potential, the comparator 200 130switch 214 by a resistor 220. The junction of 9 GB2187583A 9 the resistor 220 and the Zener diode 218 is to said labeler means for printing on a label at'L coupled to the NVRAM 60 by another block- a printing position, means for peeling the ing diode 222. Thus, when the switch 214 is printed label from the backing strip, label ap open, the NVRAM 60 is powered by the aux- plying means disposed adjacent the peeling iliary circuit. As in the case when the switch 70 means, means for advancing the web to peel 214 is on, the diode 211 isolates the battery a printed label from the backing strip at the 210 from the rest of the circuitry as long as peeling means and advance the printed label the battery 26 is present and active. By mak- into label applying relationship with the label ing the voltage of the Zener diode 218 lower applying means and to advance another label than the output voltage of the regulator 212, 75 into the printing position, means for entering for example, 4.2 volts, interaction between selected data to be printed, the printing the two circuits is eliminated. For example, means including a thermographic print head when the switch 214 is closed, the voltage having a plurality of individually selectable print appearing at the cathode of the blocking diode elements powered by the source of electrical 222 is greater than the voltage appearing at 80 energy for printing on a thermographic label at its anode. This reverse biases the diode 222 a printing position, means coupled to said and prevents currents from flowing from the data entering means for electrically processing regulator 212 into the Zener diode 218 and the selected data and energizing the individual discharging the battery 26. When the switch print elements in a predetermined sequence 214 is open, the blocking diode 216 is re- 85 determined by the selected data to print data verse biased, thus preventing the labeler cir- on the label, means for monitoring the voltage cuitry from discharging the batteries 26 and provided by the source of electrical energy for 210. If the battery 26 is removed, or be- preventing the operation of the thermographic comes discharged, the diode 211 becomes print head when the voltage drops below a forward biased and the NVRAM 60 is pow- 90 predetermined level.

ered by the battery 211. Under these condi- 2. A hand held labeling machine as recited tions, the diodes 216 and 222 isolate the bat- in claim 1, further including memory means tery 211 from all of the labeler circuitry other coupled to said processing means, wherein than the NVRAM 60. said processing means and said memory Thus it is seen that the hand-held labeler 95 means cooperate to transfer data there described includes a system for precisely between, wherein said voltage monitoring sensing the position of the web, for adjusting means is operative to prevent the transfer of the position of the web relative to the printing data between said processing means and said device with great accuracy, and for controlling memory means when the voltage drops below the energisation of the printing elements in 100 the predetermined level.

accordance with the web position in order to

Claims (6)

1. position the imprints on the web with this - CLAIMS accuracy. The web

   position sensing system is Amendments to the claims have been filed, particularly usable with a thermographic print- and have the following effect:

   ing device, and minimises the possibility of 105 Claims 1-
2. 2 above have been deleted or damage to the printing device. The web posi- textually amended.

   tioning device positions the web to an accu- New or textually amended claims have been racy of a few mils and provides a ready posi- filed as follows:

   tioning adjustment that is also accurate to 1. A hand-held labeling machine comprising within a few mils. The web can be readily 110 a housing having a manually engageable repositioned with an accuracy of a few mils to handle, the housing having means for holding compensate for manufacturing tolerances. The a label supply roll of a composite web having system controls the printing device to com- labels releaseably adhered to a backing strip, pensate for variations in the speed of the means for connecting a source of electrical web, and is usable with hand advanced and 115 energy to said labeler, means for printing on a motorised web advancing mechanisms. label at a printing position, means for peeling Obviously, many modifications and variations the printed label from the backing strip, label of the present invention are possible in light applying means disposed adjacent the peeling_ of the above teachings. Thus, it is to be un- means, means for advancing the web to peel derstood that, within the scope of the ap- 120 a printed label from the backing strip at the pended claims, the invention may be practiced peeling means and advance the printed label otherwise than as specifically described above. into label applying relationship with the label applying means and to advance another label CLAIMS into the printing position, means for entering 1. A hand-held labeling machine comprising; 125selected data to be printed, the printing a housing having a manually engageable means including a thermographic print head handle, the housing having means for holding having a plurality of individually selectable print a label supply roll of a composite web having elements powered by the source of electrical labels releaseably adhered to a backing strip, energy for printing on a thermographic label at means connecting a source of electrical energy 130 a printing position, means coupled to said GB2187583A 10 data entering means for electrically processing handle, the housing having means for holding the selected data and energizing the individual a label supply roll of a composite web having print elements in a predetermined sequence labels releasably adhered to a backing strip, determined by the selected data to print data means for connecting a source of electrical on the label, means for preventing erratic op70energy to said labeler, means for printing on a eration of said processing means including label at a printing position, means for peeling means for monitoring the voltage provided by the printed label from the backing strip, label the source of electrical energy and for pre- applying means disposed adjacent the peeling venting the operation of the processing means means, means for advancing the web to peel when the voltage drops below a predeter- 75 a printed label from the backing strip at the mined level. peeling means and advance the printed label 2. A hand-held labeling machine as recited into label applying relationship with the label in claim 1, further including memory means applying means amd to advance another label coupled to said processing means, wherein into the printing position, means for entering said processing means and said memory 80 selected data to be printed, the printing means cooperate to transfer data there- means including a thermographic print head between, wherein said voltage monitoring having a plurality of individually selectable print means is operative to prevent the transfer of elements powered by the source of electrical data between said processing means and said energy for printing on a thermographic label at memory means when the voltage drops below 85 a printing position, means coupled to said the predetermined level. data entering means for electrically processing
3. 3. A hand-held labeling machine as recited the selected data and energizing the individual in claim 1 or 2, wherein said monitoring print elements in a predetermined sequence means is operative to disable said print head determined by the selected data to print data when the voltage drops below the predeter- 90 on the label, means for preventing damage to mined level. said thermographic print head in the event of
4. 4. A hand-held labeling machine comprising erratic operation of said processing means re a housing having a manually engageable sulting from low voltage operation including handle, the housing having means for holding means for monitoring the voltage provided by a label supply roll of a composite web having 95 the source of electrical energy and preventing labels releaseably adhered to a backing strip, the operation of the thermographic print head means for connecting a. source of electrical when the voltage drops below a predeter energy to said labeler, means for printing on a mined level.

   label at a printing position, means for peeling 7. A hand-held labeling machine as recited the printed label from the backing strip, label 100 in claim 6, further including memory means applying means disposed adjacent the peeling coupled to said processing means, wherein means, means for advancing the web to peel said processing means and said memory a printed label from the backing strip at the means cooperate to transfer data there peeling means and a - dvance the printed label between, wherein said voltage monitoring into label applying relationship with the label 105 means is operative to prevent the transfer of applying means and to advance another label data between said processing means and said into the printing position, means for entering memory means when the voltage drops below selected data to be printed, the printing the predetermined level.

   means including a thermographic print head having a plurality of individually selectable print Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd, Cid 8991685, 1987.

   elements powered by the source of electrical Published at The Patent Office, 25 Southampton Buildings, energy for printing on a thermographic label at London, WC2A 1 AY, from which copies may be obtained.

   a printing position, means including memory means coupled to said data entering means for electrically processing the selected data and energizing the individual print elements in a predetermined sequence determined by the selected data to print data on the label, means for preventing erroneous alteration of data stored in said memory means including means for monitoring the voltage provided by the source of electrical energy and disabling said memory means when the voltage drops below a predetermined level.
5. 5. A hand-held labeling machine as recited in claim 4, wherein said monitoring means is operative to disable said print head when the voltage drops below the predetermined level.
6. 6. A hand-held labeling machine comprising a housing having a manually engageable