FR2547556A1 - Labelling machine including a thermographic printing device - Google Patents

Abstract

The invention relates to a labelling machine forming labels by means of thermographic printing. It relates to a labelling machine in which a keyboard 20 permits the input (loading) of data which have to be applied on the labels of a roll. The supply of the printing elements is controlled as a function of the number of elements supplied, of the electrical resistance of each element and of the voltage of the supply battery 26. Application to labelling machines in retail shops.

Description

 The present invention relates generally to printing devices and more specifically to manual labellers comprising thermographic printing devices.

Thermographic printing devices are also known, as well as manual labeling machines comprising such devices. U.S. Patent No. 4,264,396 and United States Patent Application
Numerical United States No. 268,590, filed May 29, 1981, describes examples of such manual labellers having thermographic printing devices.

 Although the devices described in the aforementioned documents allow printing to be formed on a continuous heat-sensitive sheet, they do not include numerous improvements to the device according to the invention. For example, when printing with a thermal printhead, especially with a manual printing device powered by a storage battery, the printing density varies depending on the battery voltage. In addition, since the battery voltage varies with the number of printing elements excited simultaneously, the printing density varies depending on the number of elements that must be excited simultaneously for the formation of the various parts of a character. The temperature to which each printing element is brought when it is excited is also not only a function of the amount of energy transmitted to this element but also of the previous history of this element, i.e. say of the time that has passed since this element was last excited. In known devices, defective printing elements and defective accumulators incorporated in the battery supplying the device can cause printing of defective labels before their detection, and repetitive printing of the same character can cause premature failure of the print head when certain elements of the head are repeatedly excited.

The stepping motors of known devices, used for advancing the continuous sheet of labels in front of the print head, also tend to have only a low limit torque. speed.

 The invention overcomes many disadvantages of known devices.

 It relates to a manual labeling machine having a thermographic printing device which controls the voltage applied to the printing elements and regulates the time during which the elements are excited as a function of the voltage so that a substantially constant amount of energy is applied to the elements and the print density remains substantially constant.

 It also relates to a thermal printing device which measures the resistance of the individual printing elements and regulates the time during which the individual elements are excited as a function of their resistance so that a substantially constant amount of energy is applied to the different elements and that the print density remains practically uniform.

 It also relates to a manual labeling machine having a thermal printing device which regulates the time during which the elements are excited as a function of the time which has elapsed since the printing elements have been excited.

 It also relates to a thermographic printing device which allows the detection of defective printing elements and defective accumulators in the accumulator battery.

 It also relates to a manual labeling machine having a thermographic printing device which automatically shifts the printing of repetitive characters in order to avoid premature wear of the head when repetitive characters are printed.

 It also relates to a manual thermographic printer which can print both alphanumeric characters and stick codes, such as the universal product identification code (UPC) and the article number according to the European standard (EAN).

 It also relates to a manual thermographic labeling machine into which data can be entered either by a keyboard or by coupling to an external computer.

 It also relates to a manual labeler controlled by microprocessor which regulates the time during which the various printing elements are excited as a function of the voltage of the storage battery, of the ambient temperature, of the time elapsed since the various elements have been the resistance of the various elements and any combination of these factors.

 It also relates to a manual labeling machine which comprises a direct current motor controlled by a microprocessor and intended to advance the continuous sheet of labels.

 More specifically, in a preferred embodiment, the invention relates to a manual labeling machine comprising a microprocessor-controlled printing apparatus, in which the microprocessor regulates the printing function so that it compensates for the effect of the various ambient conditions, print head and paper parameters and the characteristics of the particular information to be printed. To this end, the microprocessor monitors the voltage applied to the thermographic printing head and the resistance of each printing element as well as other parameters.

The control of the resistances of the printing elements allows the detection of an element in open circuit or in short-circuit, and allows the calculation of the amount of energy to be transmitted to the different printing elements. The detection of the battery voltage allows the detection of a defective battery and allows the adjustment of the duration during which each print element is energized according to the battery voltage and, if applicable if necessary, depending on the resistance of the printing element so that the printing density is uniform. In addition, the time during which the elements are energized is adjusted as a function of the time that has elapsed since the elements have been energized previously so that the heating and cooling characteristics of the elements are taken into account.

 When repetitive characters such as for example the extreme rods of the universal product identification code are printed, the microprocessor shifts the coded symbols so that the guard rods are printed by different printing elements on different labels. This prevents virtually continuous excitation and premature failure of the printing of the end sticks.

A keyboard as well as a circuit for coupling to a computer, are intended for the introduction of the data into the device, and a DC motor, controlled by microprocessor is used for advancing the continuous sheet in front of the head. 'impression.

Other characteristics and advantages of the invention will be better understood on reading the description which will follow of exemplary embodiments and with reference to the appended drawings in which
Figure 1 is a perspective of a manual labeler produced according to the invention
Figure 2 is a block diagram of the logic control circuit of the thermographic printing apparatus according to the invention
FIG. 3 is a plan view of a thermographic printing head, usable with the printing apparatus according to the invention
FIG. 4 is a block diagram showing an embodiment of an excitation circuit of a print head
Figure 5 is a block diagram of a variant excitation circuit of a print head
FIG. 6 is a graph showing the relationship between the voltage and the time required to obtain an impression of substantially constant density
FIG. 7 is a graph showing the heating and cooling characteristics of a printing element as a function of the time elapsed between successive excitations
Figure 8 is a plan view of the printhead and a label, showing the printing of a stick code as well as the shift of the stick code so that the probability of a premature failure of the head printing is reduced
FIG. 9 is another block diagram of a manual thermographic labeling machine according to the invention, showing the control of the motor for advancing the continuous sheet; and
FIG. 10 represents the use of the labeling machine according to the invention, in a data search and remote programming system.

 The drawings and in particular FIG. 1 represent a manual thermographic labeler controlled by microprocessor according to the invention, bearing the general reference 10. The labeling machine 10 comprises a boltier 12 which supports a roll 14 of labels 12 having an adhesive back and which are supported by a continuous sheet 18. A keyboard 20 is placed on the housing 12 and contains several switches 22 which can be individually controlled by keys so that data can be entered into the label maker. A display device 24 which may be of a liquid crystal or light emitting diode type, is also arranged on the housing so that it allows the operator to observe the data entered and the operating instructions created. by the microprocessor. A storage battery, which can be housed in a removable handle assembly 25, containing a storage battery 26 having an internal resistance 27, transmits the electrical energy necessary to the label maker 10. A trigger 28 is intended to trigger the label printing operation, and a label application roller 30 is used so that it exerts pressure on the adhesive label 16 when it is applied to an article of merchandise.

A label separating member (not shown) is housed in the housing 12 so that it separates the labels 16 from the support sheet 18. Several guide rollers are intended to guide the separate labels 16 towards the front part of the housing, below the application roller 30, and to guide the continuous support sheet towards the rear of the housing, under the roller 14.

 As indicated previously, the labeling machine according to the invention has very great flexibility and allows the printing of alphanumeric characters, as well as of bar codes, in particular the universal product identification code (UPC) and the European number code. of articles (EAN). The type of format, alphanumeric or coded, is easily selected by entering suitable data defining the format and the fonts, via the keyboard 20. The data to be printed, for example a price, data defining a product and other information concerning the product such as the size, the color, etc., is also transmitted via the keyboard 20. In addition, the number of labels to be printed can be entered.

In addition, a data input / output connector 32 can be placed on the housing so that it allows data to be entered into the label maker from an external source such as a remote computer, and that '' allows recharging of the storage battery.

 Referring now to Figure 2 which indicates that the keyboard 20 is coupled to an adapter 40 for coupling to peripheral devices which allows coupling between various input and output devices and a microprocessor 42. A sensor 44 is also coupled to the adapter 40 and it detects a notch or other mark indicating a separation between labels, a trigger switch 46 controlled by the trigger 28 and a motor control circuit 48. In a variant, the upper part of the shape sensor 44 can detect a mark or a mark of a sheet feed wheel 49 which is driven by a motor 50. The motor control circuit is itself controlled by the data from the microprocessor 42 via the adapter 40, and it controls the operation of the motor 50 which can be a stepping motor or a DC motor, the latter being preferable given the characteristics of low torque speed. An acoustic alarm system 52 is also connected to the adapter 40 and is useful for indicating to the operator that there is a real or potential problem. For example, the alarm 52 can be used for the indication of a discharged or defective battery, of a defective print head, of the lack of labels in the label maker or simply for the indication of the fact that data entered into the device have been received. In the latter case, the alarm 52 can be used to give an audible indication each time one of the keys 22 of the keyboard 20 is pressed.

 The display device 24 is coupled to the microprocessor 42 by a display control circuit 54. The display device 24 is used for indicating data transmitted to the microprocessor as well as other messages such as for example request and diagnostic messages originating from the microprocessor. A passive memory 56 is intended to contain permanent data, for example the program determining the operation of the device. The memory 56 can be permanently mounted in the labeling machine 10, or it can be temporarily installed in a socket or the like so that the font and / or the format can be modified by changing the memory 56.

In addition, a direct access memory 58, usable for storing short-term data, for example data entered by the keyboard 20, is arranged with a direct access memory 60 of permanent type, suitable for the conservation of data such as format data. The input-output connector 32 provides communications between the device and an external computer. Printing is carried out by a set 64 with a print head which contains a print head 66 and a circuit 68 for controlling this head, coupled to the adapter 40. An analog-to-digital converter 72 coupled to the adapter 40 detects the battery voltage or the voltage applied to the assembly 64, and gives a digital indication of this voltage to the adapter 40 so that the microprocessor can adjust the time during which the print head is energized by compensating for variations in battery or printhead voltage.

An example of assembly 64 is shown in simplified form in FIG. 3. In the embodiment shown, assembly 64 comprises a circuit 68 for excitation of the print head and the print head 66 disposed on a thin film substrate. A suitable set usable as set 64 is the "Kyocera" print head, manufactured by Kyoto Ceramic Company
Ltd., Japan. The "Kyocera" printhead has a single line of printing elements arranged transversely to the direction of movement of the continuous sheet 14, and it is particularly suitable for a manual labeling machine given the high density of printing elements. printing which constitute the head 66, especially when alphanumeric characters and stick codes are to be printed. A set which is particularly suitable as set 64 comprises 224 printing elements, each having a length of 0.25 mm and a width of 0.11 mm, having a distance between their centers of 0.13 mm. This configuration allows the printing of a practically continuous line.

 Each of the printing elements constitutes a heating element 80 of the resistive type (FIG. 4) which can be individually excited by the circuit 68 which contains a heater excitation transistor 82 for each of the elements 80. A door 84 controls each of the transistors 82 and a data register 86 and a data register 88 control the operation of the doors 84. Thus, when a head with 224 elements is used as head 66, 224 transistors 82 and 224 doors 84 must be arranged, and the registers 86 of input and 88 of data must each have at least 224 stages.

 The input register 86 receives the serial data from a data input line 90 under the control of clock signals applied to a line 92.

When the input register 86 is full, the data is transferred in parallel to the data register 88 under the control of a storage signal applied to the register 88 by a line 94. The input register 86 is then emptied by a reset pulse transmitted to line 96 and new data is transmitted to the input register.

 As the resistive heating elements 80 consume a large current, for example of approximately 50 mA per element, and given the very high density of the elements, for example 80 elements per centimeter, the intensity of the current consumed in the battery 26 of accumulators would be excessive if all the elements 80 were simultaneously excited. For this reason, the transistors 82 are sampled by the gates 84 so that a maximum of a quarter of the transistors 82 can be excited at any time.

 In the embodiment shown in FIG. 4, the sampling is carried out using AND doors with three inputs such as doors 84, and by validating the opening of doors 84 by block.

This is done using two block validation signals BE1 and BE2 of lines 100 and 102 respectively, and sampling signals ST1 and ST2 of lines 104 and 106 respectively. Each of the block validation signals is transmitted to half of the gates 84 so that half of the gates 84 is validated when the signal
BE1 has a high level and the other half when the signal
BE2 has a high level. The signal ST1 is transmitted to half of the gates 84 which receive the signal BE1 and to half of the gates 84 which receive the signal BE2.

Likewise, the signal ST2 is applied to the doors 84 which do not receive the signal ST1. Thus, since each door must receive a block validation signal and a sampling signal to be able to be opened, only a quarter of the doors 84 can open at some point. The data of register 88 are thus applied to the transistors 82 in four stages so that only a quarter of the transistors 82 can be excited at a given time.

 FIG. 5 shows another embodiment of a printhead excitation mechanism.

This embodiment is analogous to that of FIG. 4, but the input register 86 is divided into several smaller registers, for example seven shift registers 86 ′ with 32 stages in the embodiment shown. This arrangement has the advantage of allowing data to be entered more quickly into the system and thus allowing greater printing speed.

This is due to the fact that each of the seven registers 86 ′ can be supplied in parallel by the seven separate data lines 90 ′. Consequently, the data must be shifted thirty-two times only for the loading of the registers 86 ', while it takes 224 shifts for the loading of the register 86. However, when loading the registers 86', the 224 bits which define each line cannot be transmitted serially in registers 86 ', but the bits must be grouped so that they can be applied to the appropriate registers. This is achieved by taking a bit-over 32 from the data of a line and by applying this bit to the suitable registers with offset 86 ′. For example, when 224 bits are used for the formation of a line, the 32nd, 64th, 96th, 128th, 160th, 192nd, and 224th bits are selected and transmitted to the seven stages of a buffer circuit 108 (FIG. 5). These bits are then applied in parallel to the shift registers 86 '. Then, the 31st, 63rd, 95th, 127th, 159th, 191st and 223rd bits are applied to the buffer circuit 108 and shifted in the registers 86 '. The operation is repeated until the 1st, 33rd, 65th, 97th, 129th, 161st and 193rd bits are loaded into the buffer circuit 108 and transmitted to the registers 86 '. At this time, the seven registers 86 'contain the bits 1-32, 33-64, 65-96, 97-128, 129-160, 161-192 and 193-224. As these data completely define a line, the data registers 86 'can be transferred to a data register such as register 88 (Figure 4) or to several individual data registers 88' (Figure 5). The output signals from flip-flops 88 'can reach several AND gates 84 with three inputs, or any other suitable device intended to limit the number of individual elements which can be excited simultaneously.

 In the embodiment of FIG. 5, the sampling function which limits the number of elements which can be excited simultaneously is ensured by several circuits 83. Each of these contains 32 AND gates with two inputs and one circuit suitable for excitation of the print head-66. Such a system is simpler to some extent than that shown in Figure 4 because AND gates with only two inputs and not three inputs are required.

The use of three sampling signals S1,
S2 and S3 reduce the number of elements that can be energized simultaneously to roughly a third of the total number of printing elements.

In the embodiment of FIG. 5, the sampling signal S1 is applied to the first two and to the last of the circuits 83. The sampling signal S2 is applied to the third and to the fourth of the circuits 83, and the signal S3 to the fifth and sixth of circuits 83. Consequently, a maximum of two print elements out of seven can be excited simultaneously when the sampling signal S2 or S3 is present. In theory, three elements out of seven can be excited when the signal S1 sampling line is present but, in practice, the print line rarely has a length equal to the width of the print head 66 so that it is unlikely that more than half of the total elements of the first and the last of circuits 83 be excited
Although the number of resistive heating elements 80 which can be energized simultaneously is limited, there is some fluctuation in the voltage of the storage battery depending on the number of elements which can be energized given the internal resistance of battery. For this reason, the analog-digital converter 70 (FIG. 2) is used in combination with the adapter 40 and the microprocessor 42 for the adjustment of the time during which each of the resistive elements 80 is energized as a function of the battery voltage.

The amount of heat applied per effect
Joule by the printing elements must remain practically constant when the tension varies so that the printing keeps a constant density. The heat released by the Joule effect in each resistive element is given by the following formula
v2
J = R in which J represents the heat released by effect
Joule in each resistive element, v is the voltage applied to the element, R is the resistance of this element and t represents the time during which the resistive element is excited.

As described above, it is desirable that the amount of heat given off by the Joule effect remains practically constant so that the print density also remains practically constant. Constant heating by Joule effect is thus given by the formula v xt =
R in which K is a constant.

The determination of time t according to the above equation gives the following relation
t = KR
2
v
This relationship is represented by curve 110 in FIG. 6.

 The relationship indicated above is suitable for thermographic printing heads formed on relatively insulated substrates, that is to say for example on glass or ceramic substrates.

However, in the case of the printheads which are not so well insulated or those which can be used in ambient conditions of relatively low temperature, the heating is substantially constant by effect
Joule does not always give optimal results because the head cools relatively quickly during the relatively long period of heating. For example, in the graph in Figure 6, when the voltage is equal to V2, it takes a time equal to T1 to obtain the desired amount of heat by the Joule effect. If the voltage drops to Vl, it takes a longer time T2 for the creation of the same amount of heat by the Joule effect. When the head is well insulated and the amount of heat lost in the time interval between T1 and T2 is low or zero, the print density is not affected. However, if a significant quantity of heat is lost between times T1 and T2, an additional quantity of heat must be supplied so that it compensates for this loss. Consequently, under these conditions, the quantity of heat supplied by the Joule effect must be increased as the printhead tension decreases so that the additional loss is compensated.

A relation which linearly increases the quantity of heat supplied by the Joule effect as a function of time is given by the following relation
2
v = K + Ct
Rxt- where C is a constant proportional to the cooling characteristics of the print head. As the above equation indicates, it is analogous to the equation which provides a constant quantity of heat, apart from the addition of the term Ct so that the quantity of heat added by the Joule effect is a function of the time during which the head must be excited so that the additional heat losses, during the additional time of excitation of the head are compensated. When this equation is represented as a function of t, the following result is obtained
KR
t = kir
v - CR
This relationship is represented by curve 112 in FIG. 6 and, as the latter indicates, when the head used has significant heat losses, the excitation time must be increased from T2 to T3 so that this additional loss is compensated.

 Another factor which must be compensated for is the increase in the temperature of a printing element when the latter is successively excited. For example, when a voltage V (FIG. 7) is applied to a printing element, the temperature of the latter rises from ambient temperature Tamb to a temperature sufficient for printing to take place as represented by ia curve 120. When the application of the voltage to the printing element is finished, the latter cools exponentially as represented by curve 122.

When energy is applied to the print element again, its temperature rises again as shown by curve 124. However, if the head is re-energized before the print element has had enough time to cool to room temperature, the peak temperature which is reached at the subsequent excitation of the head is higher than the previous peak temperature. This phenomenon is cumulative, as indicated by the heating and cooling curves 126 and 128, the peak temperature reached in each heating cycle being higher than that which was reached in the previous cycle. When no compensation is provided, the peak temperature may exceed the nominal value set for the printing element (T) and may cause deterioration of the elements
pmax printing.When the amount of energy transmitted to the elements is reduced, the temperature of the heads may not reach the minimum temperature necessary for printing (T). Furthermore, it appears that when
pmin the ambient temperature (Tamb) changes, the peak temperature reached by the printing element also changes. Thus, it is desirable that the excitation time of the printing elements be adjusted as a function of the time elapsed between successive excitations and as a function of the ambient temperature so that the effects of these factors are corrected. Such compensation techniques are described later in the remainder of this specification.

 As the foregoing description indicates, the factors or elements which affect the print density can be separated into two general categories.

The first category includes items relating to the environment in which the printer operates, and it includes items such as' being of the battery, ambient temperature, paper characteristics, the speed at which the paper moves in front of the head, the intimacy of the contact between the paper and the head, and other elements. The second category includes elements which are related to the printed characters, since the characters determine the sequence of excitation of the elements and. the frequency of excitation of these elements. Some elements can fall into both the environment dependent category and the character dependent category.

An example of such an element is the voltage which is both a function of the state of the storage battery (environment) and a function of the number of printing elements which are energized simultaneously (depending on the characters) .

 Although the amount of necessary compensation for the effects of the various elements can be calculated constantly so that the print density remains constant, it has been found that it is convenient to determine necessary factors for compensation for the various elements in advance and keep them in a look-up table. The compensation factors can be kept in a multidimensional consultation table and the suitable compensation factor can be found according to the various elements to be considered. In a variant, the compensation factors can be kept in a series of consultation tables with a single variable, each containing the compensation factors for a single element. In this case, an overall compensation can be obtained by a series of individual steps.

 For example, in the case of voltage compensation, the times required to obtain a satisfactory impression at various voltages can be calculated or determined empirically. Given the large number of factors that affect the heating and cooling characteristics of a print head, the empirical approach is more direct since the print characteristics can be easily measured and stored.

 Since various elements which control the print density can be separated into character-dependent and environment-dependent elements, they can be treated separately so that the character generator circuit can operate independently of the condition compensation circuit. the environment and vice versa. This is advantageous since it allows modifications to the character generator circuit without affecting the environment compensation circuit and vice versa. In addition, a separate circuit can be used for controlling the sheet feed motor 50 so that the motor control function is independent of the print control and environmental factor compensation circuit.

 It is therefore desirable that the data determining the printed characters be created before the actual printing of the characters, since this allows the determination of all the compensation factors dependent on the characters before the actual printing of a character or group of characters. Thus, in the case of the print head of the type used in the embodiment considered, the printing of a label can be determined in the form of 100 lines of 224 points each. Thus, the information to be printed is determined by data defining the individual characters to be printed which are found in a look-up table defining the various characters. The data thus found determines those of the 224 elements (if any) which must be excited for each of the 100 lines to be printed. In addition to determining those of the 224 elements which must be excited in each of the 100 lines, the duration for which the elements must be excited must also be determined. For example, this duration is a function of the time which has elapsed since each of the excited elements has been excited previously and of the number of elements which must be excited simultaneously in each line. According to these factors, data determining the excitation time or the heating time is kept for each line of dots. For example, one byte of memory is sufficient for determining the heating time for each line, especially when stick codes are being printed because the same elements are always excited during the printing of the code and consequently the essential parameter affecting the excitation time is the number of elements which are excited simultaneously. In the case of alphanumeric characters in which different printing elements are excited when different parts of the character are printed, the previous history or the time since each element was excited the last takes more importance and information may be necessary for the determination of the excitation time. For example, different parts of a line may have different heating times, due to different previous behaviors, and this requires additional information for the determination of the various times of heater. Furthermore, the circuit must be more complex than that shown in FIGS. 4 and 5 when more than three or four different heating times are required for each line. In an extreme case, individual control of each of the printing elements may be necessary.

 The condition of the battery is one of the most important conditions for the environmental factors that affect the printing characteristics. As a result, the battery voltage is controlled by the analog-to-digital converter 70 under various conditions. Thus, the battery voltage can be controlled under open circuit conditions, under load or in both cases. A suitable load for controlling the tension is the motor 50 for advancing the sheet since it represents, for the battery, a more constant charge than the print head -64. Depending on the state of the battery, time correction factors proportional to the battery voltage can be obtained by solving one of the Joule heating equations described above or by empirical determination. once obtained, can be kept in a consultation table according to the battery voltage in open circuit or the battery voltage under load so that the corrections of the heating time imposed by the variations of the state of the battery are obtained.

 When an accumulator battery discharges, the voltage which it gives does not vary significantly but on the contrary its internal resistance 27 increases. This value can vary from a fraction of an ohm in the case of a well-charged battery to a few ohms in the case of a battery close to the discharged state. It has been found that the value of the internal resistance 27 can be easily measured and that this value constitutes a convenient means for compensating the heating time as a function of the state of the battery. For example, the value of the internal resistance 27 can be obtained by measuring the voltage between the terminals of the battery assembly 25 in the absence of charge or under a low charge such as the microprocessor 42 and the associated equipment, as well as under high load, such as the motor 50 or the head 64, or both. Once the intensities of the currents consumed at low load and at high load are known and once the voltage difference across the terminals of the assembly is known 25 of the battery under low charge, the value of the internal resistance 27 can be easily calculated. For example, when the intensity of the current from the battery under a light load is 100 mA and when the voltage across the battery 25 is 12.6 V, if the voltage across the terminals drops to 10.6 V when the current is brought to 1.1 A under high load, the drop of 2 V due to the increase of the current of 1 A indicates that the value of the internal resistance 27 is 2 ohms.

 When the range of values of the internal resistance 27 for this type of battery used in the labeling machine 10 is known, the necessary heating time can be calculated according to the value of the resistance 27 or it can be determined empirically. After determination, the heating time correction factors, determined from the resistor 27, can be kept in a look-up table and used for compensation of the heating times according to the state of the battery.

 The battery control not only provides information for determining the factors for correcting the heating time but also allows the easy detection of a defective accumulator in a battery comprising several. For example, once the voltage per accumulator and the number of accumulators in the battery are known, the voltage of the battery is known, when it operates properly. As a result, in the event of an accumulator failure, the battery voltage drops from the accumulator voltage, and the change can be easily detected so that a warning can be given. For example, in the case of a nickel-cadmium type storage battery, the voltage is approximately 1.25 V per storage battery. When an accumulator discharges completely to the point of reversing, the voltage drop can be easily detected and the operator can be informed before deterioration of the battery. For example, the voltage measurement carried out for the detection of an inverted accumulator is carried out under open circuit conditions or when the microprocessor 42 and the associated elements constitute the only load, since the load of the microprocessor is so low that it corresponds approximately at open circuit conditions.

 Since the resistance of the individual printing elements is also important in determining the amount of heat supplied by the Joule effect during excitation, it is desirable that the resistance of each of the printing elements is known. The resistance can be easily measured by circulating a current of low intensity, less than the current necessary for obtaining a print, in each of the printing elements, so that its resistance is measured. The measurement can be carried out either by circulating a current of known intensity in each element and by measuring the voltage across the element so that its resistance is calculated, or by mounting a known resistance in series with one of the wires supply of the print head and measurement of the voltage across the known resistance when each of the elements is excited. Such a measure has two functions.

It gives the values of the resistances which can be used for the heating equation by Joule effect or in the value of the heating time or in the consultation table for correction of the heating times.

When extreme precision is required, the individual resistances of the elements can be used but, if not, an average resistance of all the elements can be used instead.

Second, when maximum and minimum limits are determined for the resistance of each printing element, an open circuit or shorted element can be isolated and the operator can be informed of this phenomenon.

 Other factors that affect the print density are the ambient or substrate temperature, the characteristics of the thermographic paper used for the continuous sheet, the speed of the paper moving in front of the print head and the pressure exerted between the head and paper. These factors can also be offset if necessary. For example, the temperature of the substrate can be measured with a thermistor, the output signal of which is transmitted to an analog-digital converter which can itself be used for addressing suitable locations in a substrate temperature consultation table containing suitable values for heating time or correction factors depending on the temperature of the substrate. If necessary, a stop characteristic can interrupt the printing function when the head becomes excessively hot Paper speed and pressure of contact between the head and the paper can also be measured, and suitable corrections can be extracted from the look-up tables. The characteristics of various types of thermal paper can also be kept in a look-up table and achieved manually by transmitting the type of paper that is used, using the keyboard 20 or otherwise.

 As indicated above, the labeling machine according to the invention allows the printing of bar codes as well as alphanumeric characters. When printing the bar codes, the sticks forming the code are preferably printed longitudinally, along the sheet. , transversely or perpendicular to the direction of the length of the print head 66 (FIG. 8). The code shown in Figure 8 is a universal product identification code, but the device according to the invention can print any stick code, including the European identification code by article number and other codes. However, as the universal product code is a common code, it is used for illustrative purposes.

The universal product identification code
UPC contains both stick codes and numbers (Figure 8). The zero to the left of the stick code indicates that the item to which the code is attached is a product (and not a coupon that normally has the number 5). Ten human readable digits are located below the code and represent the value of the coded sticks that are just above the digits. For example, the first five digits identify a manufacturer and the last five a product. A series of extreme or guard rods, longer than the rods identifying the manufacturer and the product, = are placed to the left and right of the numbers identifying the manufacturer and the product and indicate to the analysis circuit the beginning and the end of the These guard bars are always the same for the type of code used, regardless of the manufacturer and product identification information contained in the code.

 Since the guard bars are always the same when a series of labels is printed, printing these bars requires that the same elements are always energized. This causes faster wear of the elements that print the guard bars than of the elements that print the manufacturer and product identification codes because these codes are variable.

Consequently, according to another important characteristic of the invention, the position relative to the head 66 according to which the code is printed varies periodically so that different printing elements 80 of the head 66 are used for printing the guard bars. Such movement is indicated by the broken arrows in Figure 8 and can be achieved in various ways. For example, the offset can be achieved by loading additional zeros before or after the information loaded in the input registers 86 (Figure 4) or 86 '(Figure 5). The offset can be carried out at various times such as for example after the printing of each batch of labels, each time the label maker is switched on, after the printing of each sheet, or even randomly.

Among the various possible times for changing the code, moving the code after each batch or each time the machine is powered up, seems preferable.

 Although various types of motors, including stepping motors, can be used as the sheet feed motor 50, it has been found that a DC motor is particularly useful as the motor 50, in part because good torque characteristics at low speed. However, when using a DC motor, a circuit for adjusting the speed and position of the DC motor shaft is necessary.

To this end, it has been found that it is advantageous to use a separate microprocessor, such as the engine control processor 130, inside the engine control circuit 48. This arrangement has two advantages. First, it frees the microprocessor 42 for the execution of its functions of printing control and compensation of the ambient conditions, and then it gives a greater flexibility of realization and operation by the independence of the function of motor control of the print control and environmental compensation functions. The various elements necessary for the implementation of the print control and compensation functions are not shown in FIG. 9 for reasons of clarity. However, it should be noted that the microprocessor 42 of FIG. 9 must be coupled to elements which are identical or analogous to the elements represented in FIG. 2 so that they perform the printing function.

 The control of the DC motor 50 can be achieved by an open loop or closed loop control assembly. However, in all cases, given the digital nature of the motor control processor 130, it is convenient to adjust the speed and the torque of the motor 50 by applying a pulse width modulated signal to the motor 50. for example, the processor 130 can transmit excitation pulses to the motor at a constant frequency and vary the width of the pulses so that the speed or the torque of the motor varies. Alternatively, pulses of variable frequency and constant width may be used, but the use of pulses of variable width and constant frequency has been determined empirically as preferable in the embodiment shown however, this may not be always the case.

 In an overall example, the microprocessor 42 transmits an order to a motor control processor 130 indicating to the latter that the motor must be started. At this time, the processor 130 transmits the pulses of suitable width to the motor 50. The latter drives a tachometer 132 which creates pulses whose frequency is proportional to the speed of the motor 50. Although various types of tachometers can be used as the tachometer 132, for example magnetic type tachometers, it has been found that it is convenient to use a light beam switching tachometer which comprises a perforated or slotted wheel placed between a light source, such as a photoemissive diode, and a photosensitive sensor which creates tachometric pulses. These pulses are applied to the processor 130, preferably via a peripheral coupling adapter, such as the adapter 40. The pulses are processed by the processor 130 which Then creates a label position signal and transmits it to the microprocessor 42 so that it indicates the position of the label relative to the print head. print start which indicates to the microprocessor 42 that a label area which can be printed is under the print head, is also created by the processor 130 under the control of the tachometric pulses. The start-of-print signal can be on two levels, that is to say it can have a high level when a printable zone is present under the print head and low when a non-suitable zone at printing is present. The paper position signal can be simply a consistent reproduction of the tachometer output signal 132, or a multiple or submultiple of the frequency of the tachometer signal. In a variant, the processor 130 can count the pulses of the tachometer and transmit a paper position signal representative of the number of tachometric pulses that have been counted during the advance of a particular label. The processor 130 also cooperates with the upper part of the shape sensor 44 for determining the position of the upper part of a label, this detector noting a mark such as a notch or a mark printed on the continuous sheet 14, indicating the separations between the individual labels 16, so that a position reference is thus available for the assembly.

 As described above, the motor 50 can be controlled in open loop or in closed loop. When using an open loop, the characteristics of the motor 50 must be determined empirically or in another way so that the width of the excitation pulses which must be applied to the motor 50 is determined to obtain the desired characteristic of speed or torque. These pulse width values can be kept in a look-up table, for example in a passive memory 134 which can be placed inside or outside the processor 130. A large amount of information on widths d The pulses can be kept in memory 134 so that it allows very sophisticated control of the motor. Such data may include data allowing a progressive increase in the speed of the motor when it is started up for the first time. maintaining a constant printing speed, then gradually reducing the motor speed when printing has been completed. Thus, the information determining the pulse width which gives the necessary printing speed must be preserved, as well as the sequence of pulse widths which gives the initial progressive increase and the final progressive reduction in speed when the printing is complete.

 In the case of an open loop system as described above, the pulses of the tachometer 132 are simply used for position information, but in the case of a closed loop system, they are also used for the control of engine speed. In the case of a closed loop, the information on the width of the pulses used for the speed control is not memorized, but the frequencies of the tachometric pulses which correspond to the various motor speeds are kept in memory 134. When the motor speed must be adjusted, the frequency of the tachometric pulses is determined and compared with the frequency corresponding to the desired speed kept in the passive memory 134.

According to this comparison, the processor 130 adjusts the width of the excitation pulses of the motor 50 until the frequency of the pulses of the tachometer 132 corresponds to that which is kept in the passive memory 134. As in the case of an open loop, the progressive increase in speed, the maintenance at constant speed and the progressive reduction in speed can be obtained by memorizing the frequencies for the various operating phases, in the passive memory 134.

 Since the motor 50 receives voltage pulses as shown in FIG. 7, its speed can be determined by measuring the voltage or the electromotive force created by the motor between the voltage pulses. This can be achieved using an analog-digital converter such as the converter 136, used for sampling the voltage (forced back electromotive) created by the motor 50 between the pulses applied to it. Since the counterelectromotive force of an engine is related to the speed at which this engine rotates, this counterelectromotive force gives an indication of the speed of the engine 50 and eliminates the need for the use of a tachometer such as the tachometer 132 in a closed loop. When the counter electromotive force is used for adjusting the motor speed in a closed loop, the analog-digital converter 136 samples the counter electromotive force created by the motor 50 at periodic intervals and gives a digital representation of the voltage sampled at processor 130 (or at another microprocessor such as microprocessor 42 when no motor control processor is used, as in the case of FIG. 2). This digital representation is then compared with stored digital representations of the voltage, corresponding to various desired operating speeds, and the width (or frequency) of the pulse applied to the motor 50 is adjusted until the counterelectromotive force created by the motor 50 corresponds to one of the digital representations of the voltage. As in the previously described case of a closed loop, the progressive increase in speed, its maintenance at constant value and its progressive reduction can be obtained by preserving digital representations of the various voltages (counter-electromotive forces) necessary for the various phases of operation, in passive memory 134.

 As the labeling machine according to the invention can provide data processing, it can be used for data collection and for receiving data from a remote source such as a central computer 138 (FIG. 10) which can be coupled to the label maker 10 by a suitable coupling circuit 140.

For example, one type of use of the label maker according to the invention for data collection includes storing the number of labels of various types which were printed when the labels were applied to goods. This information can later be read by a computer 138 via the coupling circuit 140 which is connected to the connector 32. This information can be an aid for inventory management by indicating to the central computer 138 the type and quantity of goods which have been labeled and sold on the sales surfaces. In addition, an operator making the inventory can manually enter data determining the nature and the quantity of goods in stock in the labeling machine according to the invention in order to collect inventory data which is intended to be subsequently transmitted to the central computer 138 In addition, the computer 138 can be used for the transmission of data to the label maker 10, this data corresponding to the information to be printed on the labels as well as the number of labels printed
This reduces the likelihood of error due to incorrect entry of data by an operator, and can allow the operator to apply the labels to merchandise items without having to enter data at all.

Such a system eliminates the need for pre-printing of the labels, as is sometimes done using a stationary office printer and avoids the need for physical transport of the labels from the printer to the goods so that the possibility of applying labels on bad articles is reduced.

 Of course, various modifications can be made to the devices which have just been described only by way of nonlimiting examples without departing from the scope of the invention.

Claims (10)

 1. Manual labeling machine, characterized in that it comprises a case (12) having a handle intended to be grasped by hand, the bolt holder comprising a device for supporting a roll (14) of reserve labels, comprising a composite continuous sheet in which labels temporarily adhere to a support strip, a device (64) for printing a label at a printing position, a device for peeling the printed label so that it separates from the backing strip, a label applying device (30) placed near the peeling device, a device (49) for advancing the sheet so that a printed label is peeled off from the backing strip at the level of the peeling device and that the printed label advances in the position for applying the label relative to the application device, another label advancing in the printing position, a device (20) for introducing selected data to print, device (64) c including a thermographic printing head (66) having a plurality of printing elements which can be individually energized and supplied by an electric power source so that an impression is formed on a thermographic label at the printing position, a device selective excitation of the predetermined print elements, a device for detecting the voltage applied to the print head (66), a device for determining the resistance of the print elements (80) of the print head , and a device controlled by the voltage applied to the print head and by the resistance of the printing elements (80) and intended to modify the time during which the various printing elements are excited as a function of the resistance of the print element and print head tension.  2. Manual labeling machine, characterized in that it comprises a housing (12) having a handle intended to be gripped by hand, the housing having a device for supporting a label reserve roll comprising a composite sheet having labels temporarily adhering to a carrier tape, a device (64) for printing a label at a printing position, a device for peeling the printed label so that it separates from the carrier tape carrier, a label application device (30) placed near the peeling device, a device (49) for advancing the continuous sheet so that the printed label is removed from the carrier strip at the peeling device and that the printed label advances in the application position relative to the label application device, another label advancing in the printing position, a device (20) for inputting selected data to be printed, the device (64 ) including a print head thermographic ion (66) having a plurality of printing elements (80) which can be individually energized, supplied by an electric power source so that a thermographic label is printed at the printing position, a selective excitation device d predetermined printing elements (80) for predetermined time intervals, a device intended to give a digital indication representative of the excitation sequence of each of the printing elements, a device intended to keep this digital indication, and a digital device controlled by the stored digital indications and intended to modify the predetermined time intervals as a function of the stored digital indication.  3. Label maker ma nue 1 1 e, characterized in that it comprises a bolt holder (12) having a handle intended to be gripped by hand, the bolt holder comprising a device for supporting the label reserve roll comprising a sheet continuous composite with labels temporarily adhering to a support strip, a label printing device (64) at a printing station, a device for peeling the printed labels so that they separate from the support strip, a label application device (30) placed near the peeling device, a continuous sheet advance device (49) so that a printed label is removed from the carrier strip at the peeling and the printed label advances in the application position relative to the label application device, another label advancing to the printing station, a device (20) for introducing selected data to be printed, the device printing (64) including ant a thermographic printing head (66) placed at the printing station, the printing head having several thermographic printing elements (80) intended to be individually excited and arranged in a straight line arrangement transverse to the direction moving the continuous sheet and supplied by the electric power source so that a thermographic label is printed at the printing station, a device for the selective excitation of predetermined elements having a predetermined relationship in space with each other with respect to each other so that they form a predetermined pattern in the form of a bar code, and a device for selectively exciting different predetermined elements (80) having the same predetermined spatial relationship with respect to each other so that the same design in the form of a bar code is formed on the continuous sheet at a location laterally distant from the first predetermined design of bar code.  4. Manual labeling machine, characterized in that it comprises a housing (12) having a handle intended to be gripped by hand, the bolt maker having a device for supporting a label reserve roll comprising a continuous composite sheet having labels temporarily adhering to a support strip, a device (64) for printing a label at a printing position, a device for peeling the printed label so that it separates from the support strip, a label application device (30) placed near the peeling device, a continuous sheet advance device (49) so that a printed label is peeled off from the support strip at the device peeling and that the printed label advances in the application position relative to the label application device and that another label advances in the printing position, a device (20) for introducing selected data to be printed, the printing device (64) A device comprising a thermographic printing head (66) having a plurality of printing elements (80) which can be individually selected and which are supplied by an electric power source so that a thermographic label is printed on the printing device. printing, a device for applying an excitation voltage by the source of electrical energy to the print head (66), a device for selectively exciting predetermined printing elements (80), a device for detecting the voltage applied to the print head and for forming a digital representation of this voltage, and a digital device controlled by the digital representation formed by the voltage detection device and intended to determine the duration during which the various print elements must be energized depending on the voltage applied to the print head.  5 Manual labeling machine, characterized in that it comprises a bolt case (12) having a handle intended to be gripped by hand, the case having a device for supporting a roll of reserve labels in the form of a continuous strip composite having labels temporarily adhering to a support strip, a device (64) for printing a label at a printing position, a device for separating the printed label by peeling from the support strip, a device (30) for label application placed near the peeling device, a device (49) for advancing the continuous sheet so that a printed label is peeled off from the support strip at the peeling device and as the printed label advances in the application position relative to the label application device, another label advances in the printing position, a device (20) for introducing selected data to be printed, the device (64 ) impr ession comprising a thermographic printing head (66) having several elements intended to be individually excited and supplied by an electrical energy source so that a thermographic label is printed in the printing position, the electrical energy source comprising a battery accumulators (26), the labeling machine further comprising a device for applying an excitation voltage from the battery to the print head (66), a device for selective excitation of predetermined printing elements (80) , and a device for detecting the voltage produced by the storage battery, intended to give an indication when the voltage of the battery falls below a predetermined level.  6. Manual labeller, characterized in that it comprises a bolt-holder (12) having a handle intended to be gripped by hand, the bolt-maker having a device for supporting a label reserve roll comprising a continuous composite strip having labels temporarily adhering to a support strip, a device (64) for printing a label at a printing position, a device for separating the printed label by peeling from the support strip, a device (30 ) label application placed near the peeling device, a device (49) for advancing the continuous sheet so that a printed label is separated from the support strip by peeling at the peeling device and that the the printed label advances in the application position relative to the label application device, another label advances in the printing position, a device (20) for introducing selected data to be printed, the printing device ( 64) comprising a thermographic printing head (66) having a plurality of printing elements intended to be individually selected and supplied by an electric power source so that a thermographic label is printed at the printing position, a device intended .applying an excitation voltage from the electric power source to the print head (66), a device controlled by the selected data and intended to selectively excite the predetermined printing elements as a function of the data, a device intended to give an indication which is a function of the number of printing elements (80) which are to be energized simultaneously at a given time, and a device intended to determine the time during which the individual printing elements (80) are to be excited, the device for determining this duration being controlled by the aforementioned indication so that it regulates said duration during which the printing elements must be energized as a function of the number of printing elements (80) that are energized simultaneously.  7. Manual labeling machine, characterized in that it comprises a housing (12) having a handle intended to be gripped by hand, the housing having a device for supporting a label reserve roll comprising a continuous composite sheet having labels temporarily adhering to a support strip, a device (64) for printing a label at a printing position, a device for separating the printed label by peeling from the support strip, a device (30 ) label application placed near the peeling device, a device (49) for advancing the continuous sheet so that a printed label is separated from the support strip at the peeling station, and that the printed label advances in the application position relative to the label application device, another label advancing in the printing position, a device (20) for inputting selected data to be printed, the printing device (64) comprising a head of thermographic printing (66) having a plurality of printing elements (80) intended to be individually energized by an electric power source so that a thermographic label is printed in the printing position, an application device an excitation voltage from the electrical power source to the print head (66), a device for selectively exciting predetermined print elements (80) according to the selected data, an individual device for determining the resistance of each of the individual print elements (80) in the print head, and a device for providing an indication when the resistance of any of the print elements (80) is not included in a predetermined range of resistances.  8. Manual labeling machine, characterized in that it comprises a housing (12) having a handle intended to be grasped by hand, the bolt maker having a device for supporting a label reserve roll including a continuous composite sheet having labels temporarily adhering to a support strip, a device (64) for printing a label at a printing position, a device for separating the printed label by peeling from the support strip, a device (30 ) label application placed near the peeling device, a device (49) for advancing the continuous sheet so that the printed label is separated from the carrier strip by peeling at the peeling device and that the printed label advances to the application position relative to the label application device and advances another label to the printing position, a device (20) for inputting selected data to be printed, the printing device Ssion (64) comprising a thermographic printing head (66) having a plurality of printing elements (80) which can be selected individually and which are supplied by an electric power source so that a thermographic label is printed at the position printing device, a device (130) coupled to the data input device and intended to electrically process the selected data and to excite the individual printing elements (80) according to a predetermined sequence which is itself determined by the data selected so that data is printed on the labels, the feed device comprising a direct current motor (50) electrically connected to the processing device, a tachometer (132) connected to the direct current motor and the processing device so that '' it gives a tachometric signal representative of the speed of the DC motor to the processing device, the latter comprising a device intended for applying er electrical pulses to the DC motor (50) so that the latter advances the sheet.  9. Manual labeling machine, characterized in that it comprises a housing (12), having a handle intended to be gripped by hand, the housing having a device for supporting a label reserve roll comprising a continuous composite sheet to which labels temporarily adhere to a carrier sheet, a device (64) for printing a label at a printing position, a device for separating the printed label by peeling from the carrier strip, a device (30) for label application placed close to the peeling device, a device (49) for advancing the continuous sheet so that a printed label is separated from the support strip by peeling at the peeling device and that the printed label advances in the application position relative to the label application device, another label advances in the printing position, a device (20) for introducing selected data to be printed, the device for i printing (64) comprising a thermographic printing head (66) having a plurality of printing elements (80) which can be individually selected and which are supplied by an electric power source so that a thermographic label is printed at the position printing device, a device (130) coupled to the data input device and intended to electrically process the selected data and to excite the individual printing elements (80) in a predetermined sequence which is itself determined by the data selected so that data is printed on the label, the feed device comprising a direct current motor (50) electrically coupled to the processing device, the latter comprising a device for applying electrical pulses to the direct current so that the latter advances the sheet, and a device coupled to the direct current motor and to the processing device and intended to determine er the counter-electromotive force created by the DC motor between the electrical pulses applied to it, and to give a signal representative of the speed of the DC motor to the processor as a function of the counter-electromotive force.  10. Manual labeling machine, characterized in that it comprises a case (12) having a handle intended to be gripped by hand and a device for supporting a label reserve roll comprising a continuous composite sheet on which labels temporarily adhere to a carrier tape, a label printing device (64) at a printing position, a device for separating the printed label by peeling off the carrier tape, a device (30) for applying a label placed from the peeling device, a device (49) for advancing the sheet so that the printed label is separated from the support strip by peeling at the peeling device and the printed label advances in label application position relative to the label application device, another label advancing to the printing position, a device (20) for inputting selected data to be printed, the printing device (64) including a head thermographic printing unit (66) having a plurality of printing elements (80) which can be selected individually and which are supplied by the electric power source so that a thermographic label in the printing position is printed, a device (130 ) connected to the data input device (20) and intended to electrically process the selected data and to excite the individual printing elements (80) according to a predetermined sequence which depends on the selected data so that data is printed on the label, the advance device (49) comprising a signaling device electrically connected to the processing device so that it transmits a signal representative of the position of the label, this signaling device comprising a device intended to form a representative signal a label area which can be printed, the processing device comprising a device controlled by this zone signal e which can be printed and forming a device for controlling the print head so that it places the data on the label.